LIBRARY
UNIVERSITY OF CALIFORNIA
DAVIS
RICHTER'S ORGANIC CHEMISTRY
VOLUME II OF THIS WORK INCLUDES THE CARBOCYCLIC
AND VOLUME III. THE HETEROCYCLIC SERIES
ORGANIC CHEMISTRY
OR
:HEMISTRY OF THE CARBON COMPOUNDS
BY
VICTOR VON RICHTER
EDITED BY PROF. R. ANSCHUTZ AND PROF. G. SCHROKTER
VOLUME I
CHEMISTRY OF THE ALIPHATIC SERIES
NEWLY TRANSLATED AND REVISED FROM THE GERMAN EDITION
(AFTER PROF. EDGAR F. SMITH'S THIRD AMERICAN EDITION)
BY
PERCY E. SPIELMANN, PH.D., B.Sc., F.I.O, A.R.C.SC.
LONDON
KEGAN PAUL, TRENCH, TRUBNER & CO., LTD
PHILADELPHIA: P. BLAKISTON'S SON & CO.
1922
LIBRARY
FIRST EDITION .... 1915
SECOND EDITION (REVISED) 1919
SECOND IMPRESSION . . 1921
THIRD IMPRESSION . . 1922
Printed in Great Britain by Butler & Tanner, Frame and London
PREFACE TO THE FIRST ENGLISH
EDITION
A COMPARISON between the present work, the latest edition of the
German original, and the last American translation, will show that
while the German text-book has been faithfully followed, modifications
have been introduced which will be regarded, it is hoped, in the light
of solid improvement. Certain statements have been corrected or
modified, changes which have usually been indicated, and a great
number of minor alterations have been made in the marshalling of
facts and the setting out of formulae with the object of a more logical
sequence and a clearer emphasis of the point under discussion.
References to German literature have been retained with the
object of preserving to the student the advantages of the origin of the
book; the English references will be otherwise readily obtainable
by him.
I take great pleasure in expressing my gratitude to Mr. W. P.
Skertchly, F.I.C., not only for assistance in the more mechanical part
of the translation, but also for the careful way in which he has read
through the proofs.
Furthermore, to Mr. A. J. Greenaway, Sub-Editor of the Journal
of the Chemical Society, I offer my most cordial thanks for his valued
advice on certain doubtful points of nomenclature.
:
PERCY E. SPIELMANN.
NDON, 1915.
N.B. — The Publishers beg to explain that a year's delay has
occurred in the production of this volume (announced for the autumn
of 1914), owing to Dr. Spielmann's employment on important work
connected with explosives for the Government.
K. P. T. T. & Co., LTD.
PREFACE TO THE SECOND ENGLISH
EDITION
NOTWITHSTANDING the depletion of students from the many Technical
Institutions as a result of the late war, a second edition of the first
volume of this text-book has been called for — a gratifying recognition
of its continued and increasing usefulness.
As inevitable to the first production of a book of this character,
with its innumerable formulae and figures, a certain number of mis-
prints had crept in, and a careful search for these has been made.
The need of such rectifications must not deter me from paying a
tribute to the printers, Messrs. Clowes and Sons, for the care and success
with which they have carried through so complicated a piece of type
setting ; while to the Publishers is due acknowledgment for much
that was of assistance in my share of the work of production.
It is believed that, in its revised form, this volume will be found to
meet all the requirements of the daily expanding class of chemical
students, on whose services will depend so important a share in the
scientific foundation of the firm establishment and success of British
Industry.
PERCY E. SPIELMANN.
LONDON, 1919.
PREFACE TO THE THIRD AMERICAN
EDITION
IN presenting this translation of the eighth German edition of
v. Richter's " Organic Chemistry " the writer has little to add to what
has previously been expressed in the prefaces to the preceding American
editions of this most successful book. The student of the present
edition will, however, very quickly discover that the subject-matter,
so ably edited by Professor Anschiitz, is vastly different from that
given in the earlier editions. Indeed, the book has sustained very
radical changes in many particulars, and certainly to its decided
advantage. The marvellous advances in the various lines of synthetic
organic chemistry have made many of the changes in the text abso-
lutely necessary, and for practical reasons it has seemed best to issue
this new edition in two volumes.
Eminent authorities, such as Profs, v. Baeyer, E. Fischer, Waitz,
Claisen, and others, have given the editor the benefit of their super-
vision of chapters relating to special fields of investigation in which
they are the recognized authorities.
The translator here acknowledges his great indebtedness to his
publishers, P. Blakiston's Son & Co., for their constant aid in his work,
as well as to Messrs. Wm. F. Fell & Co., for the care they have taken
and the skill they have displayed in the composition of what will
generally be admitted to be a difficult piece of typography.
E. F. SMITH.
PREFACE TO THE SECOND AMERICAN
EDITION
THE present American edition of v. Richter's " Organic Chemistry "
will be found to differ very considerably, in its arrangement and size,
from the first edition. The introduction contains new and valuable
additions upon analysis, the determination of molecular weights,
recent theories on chemical structure, electric conductivity, etc.
The section devoted to the carbohydrates has been entirety rewritten,
and presents the most recent views in regard to the constitution of
vm
PREFACES
this interesting ^roup of compounds. The sections relating to the
trimethylene, tetramethylene, and pentamethylene series, the fur-
furane, pyrrol, and thiophene derivatives, have been greatly enlarged,
while the subsequent chapters, devoted to the discussion of the
aromatic compounds, are quite exhaustive in their treatment of special
and important groups. Such eminent authorities as Profs. Ostwald,
von Baeyer, and Emil Fischer have kindly supervised the author's
presentation of the material drawn from their special fields of
investigation.
The characteristic features of the first edition have been retained,
so that the work will continue to be available as a text-book for
general class purposes, useful and reliable as a guide in the preparation
of organic compounds, and well arranged and satisfactory as a refer-
ence volume for the advanced student as well as for the practical
chemist.
The translator would here express his sincere thanks to Prof. v.
Richter, whose hearty co-operation has made it possible for him to
issue this translation so soon after the appearance of the sixth German
edition.
E. F. SMITH.
PREFACE TO THE FIRST AMERICAN
EDITION
THE favourable reception of the American translation of Prof, von
Richter 's " Inorganic Chemistry " has led to this translation of the
" Chemistry of the Compounds of Carbon," by the same author. In
it will be found an unusually large amount of material, necessitated
by the rapid advances in this department of chemical science. The
portions of the work which suffice for an outline of the science are
presented in large type, while in the smaller print is given equally
important matter for the advanced student. Frequent supplementary
references are made to the various journals containing original articles,
in which details in methods and fuller descriptions of properties, etc.,
may be found. The volume thus arranged will answer not only as
a text -book, and indeed as a reference volume, but also as a guide
in carrying out work in the organic laboratory. To this end numerous
methods are given for the preparation of the most important and the
most characteristic derivatives of the different classes of bodies.
E. F. SMITH.
ABBREVIATIONS
A. . < » . Liebig's Annalen der Chemie. Spl. — Supplementband.
A. chini. phys. . . Annales de chemie et de physique.
Am. .... American Chemical Journal.
Anorg. Ch. . . . Richter-Klinger, Lehrbuch der anorganischen Chemie.
Richter-Smhh, Text-book of Inorganic Chemistry.
Arch. exp. Path. . . Archiv fur experimentelle Pathologic und Pharmakologie.
Arch. ges. Phys. . . Archiv fur die gesammte Physiologic.
[a]D .... Specific optical rotation.
B Berichte der deatschen chemischen Gesellschaft.
R = Referate.
Bp. .... Boiling point. Bp10 = Boiling point at 10 mm. pressure of
mercury.
Bull. soc. chim. . . Bulletin de la socie'te chimique de Paris.
C. .... Chemisches Centralblatt.
Ch. Ztg. . . . Chemiker-Zeitung.
C.r. .... Comptes rendus des stances de 1'Academie des sciences.
D. . . . Density, specific gravity, D20= Sp. gr. at 20° C.
A1, A2, A3, etc. . . Denotes the position of a double linkage in a carbon chain,
reckoned from the C-atom i, 2, 3, etc. to the next
higher member.
D. R. P. . . . Deutsches Reichspatent.
Gaz. chim. ital. . . Gazetta chimica italiana.
F. Hd-w. . . . Fehling's Handworterbuch fur Chemie.
. Jahresbericht fur die Fortschritte der Chemie.
J. Chem. Soc. . . Journal of the Chemical Society.
J. pr. Ch.t or y. pr. Ch.
N. F. . . . Journal fur praktische Chemie. Neue Folge.
L. Hdw. . . . Ladenburg's Handworterbuch filr Chemie.
M. . . . Monatshefte fiir Chemie.
Pharm. Centr. . . Pharmaceutische Centralhalle.
Phil. Mag. . . . Philosophical Magazine.
Pogg. A., or Wied. A. . Annalen der Physik und Chemie, published by Poggendorf ;
or new series, published by Wiedemann.
R SteB.
R. Meyer's J. . Richard Meyer's Jahrbuch der Chemie.
Wied. A. . .See Pogg. A.
Wien. Monaish. . Monatsheft fiir chemie (Vienna).
Z. . Zeitschrift fiir Chemie.
Z. anal. Ch. . . Zeitschrift fiir analytische Chemie.
Z. angew. Ch. ' . Zeitschrift fiir angewandte Chemie.
Z. anorg. Ch. . Zeitschrift fiir anorganische Chemie.
Z. Elcctroch. . . Zeitschrift fiir Electrochemie.
Z. Kryst. . . Zeitschrift fur Krystallographie und Mineralogie.
Z.fhys.Ch. . • • Zeitschrift fiir physicalische Chemie.
Z. physiol. Ch* . . Hoppe-Seyler's Zeitschrift fur physiologische Chemie.
CONTENTS
INTRODUCTION
PAG*
Determination of the Composition of Carbon Compounds ..... 2
Determination of the Molecular Formula ..... . . 9
18
42
• 43
60
. 61
. . 65
68
The Chemical Constitution of the Carbon Compounds
The Nomenclature of the Carbon Compounds .
Physical Properties of the Carbon Compounds .
Heat of Combustion of Carbon Compounds .
Action of Heat, Light, and Electricity upon Carbon Compounds
The Direct Combination of Carbon with other Elements .
Classification of the Carbon Compounds . .
I. FATTY COMPOUNDS, ALIPHATIC SUBSTANCES
OR METHANE DERIVATIVES, CHAIN OR
ACYCLIC CARBON DERIVATIVES .... 69
I. HYDROCARBONS .... 69
A. Saturated or Limit Hydrocarbons, Paraffins, Alkanes, Marsh Gas or Methane
Hydrocarbons ........... 69
B. Unsaturated Hydrocarbons. I. Olefines or Alkylenes, 79; 2. Acetylenes or
Alkines, 85 ; 3. Diolefines, 90; 4. Olefine Ace'ylenes, 91 ; 5. Diacetylenes,
91 ; 6. Triolefines '.......... 91
II. HALOGEN DERIVATIVES OF THE HYDROCARBONS 91
OXYGEN DERIVATIVES OF THE METHANE
HYDROCARBONS .... 98
III. THE MONOHYDRIC ALCOHOLS AND THEIR
OXIDATION PRODUCTS . 100
I. Monohydric Alcohols, 100. A. Saturated Alcohols, Paraffin Alcohols . . 109
B. Unsaturated Alcohols, 123. I. Olefine Alcohols, 123; 2. Acetylene
Alcohols, 125 ; 3. Diolefine Alcohols . . . . . .125
Alcohol Derivatives. I. Simple and Mixed Ethers, rz$ ; 2. Esters of
the Mineral Acids, 130; 3. Sulphur Derivatives of the Alcohol
Radicals ........... 142
4. Selenium and Tellurium Compounds ...... 148
;. Nitrogen Derivatives of the Alcohol Radicals ..... 148
Phosphorus Derivatives of the Alcohol Radicals . . . . 173
I:
xii
CONTENTS
7. Alkyl Derivatives of Arsenic, 175 ; 8. Antimony, 179 ; 9. of Bismuth,
179; 10. of Boron, 180; n. of Silicon, 180 j 12. of Germanium .
13. Tin Alkyl Compounds .........
14. Metallo-organic Compounds ........
2. Aldehydes, and 3. Ketones .........
2 A. Aldehydes of the Saturated Series .......
j „ Halogen Substitution Products of the Saturated Aldehydes
Peroxides of the Aldehydes .......
2. Ethers and Esters of Methylene and Ethylidene Glycols . •
3. Sulphur Derivatives of the Saturated Aldehydes . . •
4. Nitrogen Derivatives of the Aldehydes . . . . •
2B. Olefine Aldehydes
2C. Acetylene Aldehydes
3A. Ketones of the Saturated Series .......
1. Halogen Substitution Products of the Ketones •
2. AlUyl Ethers of the Ortho-ketones
3. Ketone Halides .........
4. Ketone Bisulphites and Sulphoxylates
5. Sulphur Derivatives of the Saturated Ketones ....
6. Nitrogen Derivatives of the Ketones .....
3B. Olefine and Diolefine Ketones .......
3C. Acetylene Ketones
4. Monobasic Carboxylic Acids . . . . . . .
A. Monobasic Saturated Acids
Derivatives of the Fatty Acids
1. Esters of the Fatty Acids
2. Acid Halides of the Fatty Acids
3. Acid Anhydrides
4. Acid Peroxides . .
5. Thio-Acids
6. Acid Amides .
7. Acid Hydrazides
8. Acid Azides
9. Fatty Acid Nitriles
10. Amide Chlorides
11. Imide Chlorides .
12. Imido-Ethers
13. Thiamides
14. Thio-imido-Ethers
15. Amidines .
16. Hydroxamic Acids
17. Hydroximic Acid Chlorides
18. Nitrolic Acids ......
19. Amidoximes or Oxamidines ....
20. 21. Hydroxamic Oxime ; Nitrosoximes .
22, 23. Hydrazidine and Hydrazo-oxime
24. Ortho-fatty Acid Derivatives
Halogen Substitution Products of the Fatty Acids
B. Oleic Acids, Olefine Monocarboxylic Acids
C. Acetylene Carboxylic Acids .....
D. Diolefine Carboxylic Acids
PACK
181
182
183
189
191
201
203
204
208
210
214
2I5
216
224
225
225
225
225
226
228
232
232
235
265
265
269
271
273
273
274
278
278
278
281
281
281
281
282
282
282
283
283
2So3
284
284
284
284
290
302
305
IV. DIHYDRIC ALCOHOLS OR GLYCOLS, AND
THEIR OXIDATION PRODUCTS . . 306
I. Dihydric Alcohols or Glycols ......... 307
Glycol Derivatives , . . . .316
1. Alcohol Ethers of the Glycols . . .. . . .316
2. Esters of the Dihydric Alcohols 319
3. 1 hio-Compounds of Ethylene Glycols ..... 324
4. Nitrogen Derivatives of the Glycols ... . 327
CONTENTS xiii
2. Aldehyde-Alcohols, 337 ; Nitrogen-containing Derivatives of the Aldehyde-
Alcohols ............ 339
3. Ketone-Alcohols or Ketols, 340 ; Nitrogen-containing Derivatives of the
Ketone-Alcohols ........... 344
4. Dialdehydes ............ 346
5. Ketone-Aldehydes, or Aldehyde-Ketones ....... 348
6. Diketones, 348 ; Nitrogen-containing Derivatives of the Dialdehydes, Alde-
hyde-Ketones and Diketones ........ 353
7. Alcohol- or Hydroxy-acids ......... 356
A. Saturated Hydroxymonocarboxylic Acids, 362 ; o- Hydroxy-acids, 362 ;
/3-Hydroxycarboxylic Acids, 369 ; 7- and 0-Hydroxy-acids, 371 ;
Sulphur Derivatives of the Hydroxy-acids, 376 ; Nitrogen Derivatives
of the Hydroxy-acids, 378 ; Amino-Fatty Acids, 385 ; Dipeptides
and Polypeptides ......... 390
B. Unsaturated Hydroxy-acids, Hydroxy-olefine Carboxylic Acids . . 397
8. Aldehyde-acids, 400 ; Nitrogen Derivatives of the Aldehyde-acids . . . 402
9. Ketonic Carboxylic Acids . . . . . . . . . . 406
A, Saturated Ketone Carboxylic Acids. I. o-Ketonic Acids, 407 ; Nitrogen
Derivatives of the o-Ketonic Acids, 409. II. |8-Ketonic Acids, 410 ;
Acetoacetic Acid, 410 ; Nitrogen Derivatives of 0-Ketonic Acid,
419 ; Halogen Substitution Products of the 0-Ketonic Esters, 420.
III. 7-Ketonic Acids, 421 ; Nitrogen Derivatives of the 7-Ketonic
Acids, 423. IV. 8-Ketonic Acids 424
B. Unsaturated Ketonic Acids ; Olefine Ketonic Acids .... 425
CARBONIC ACID AND ITS DERIVATIVES . . 425
Chlorides of Carbonic Acid, 430 ; Sulphur Derivatives of Ordinary Carbonic
Acid 431
Amide Derivatives of Carbonic Acid, 435 ; Carbamide Urea, 438 ; Ureides,
441 ; Hydrazine-, Azine-, and Azido-Derivatives of Carbonic Acid, 446 ;
Sulphur-containing Derivatives of Carbamic Acid and of Urea . . . 448
Guanidine and its Derivatives ......... 454
Nitriles and Imides of Carbonic and Thiocarbonic Acids, 459 ; Oxygen Deriva-
tives of Cyanogen, their Isomerides and Polymerides, 460 ; Halogen Com-
pounds of Cyanogen and its Polymers, 465 ; Sulphur Compounds of
Cyanogen, their Isomers and Polymers, 466 ; Cyanamide and the Amides
of Cyanuric Acid, 47 1 ; Ketenes ........ 474
10. Dibasic Acid, Dicarboxylic Acids ........ 476
A. Paraffin Dicarboxylic Acids, 476 j Oxalic Acid and its Derivatives, 480 ;
Nitriles of Oxalic Acid, 484 ; the Malonic Acid Group, 487 ; Carbon
Suboxide, 488 ; Ethylene Succinic Acid Group, 491 ; Nitrogen-
containing Derivatives of the Ethylene Succinic Acid Group, 496 ;
Halogen Substitution Products of the Succinic Acid Group, 499;
Glutaric Acid Group, 501 ; Group of Adipic Acid and Higher
Normal Paraffin Dicarboxylic Acids ...... 5°4
B. Olefine Dicarboxylic Acids, 507 ; Fumaric Acid, 509 ; Maleic Acid,
510; The Isomerism of Fumaric and Maleic Acids, 512; Itaconic
Acid, 515; Citraconic Acid, 516; Mesaconic Acid . . .516
V. TRIHYDRIC ALCOHOLS : GLYCEROLS AND
THEIR OXIDATION PRODUCTS . . 523
1. Trihydric Alcohols, 524. A. Glycerol Esters of Inorganic Acids, 529. B.
Glycerol Fatty Acid Esters, Glycerides, 530; Glycerol Ethers, 531;
Nitrogen Derivatives of the Glycerols ....... 533
2. Dihydroxy- Aldehydes 533
3. Dihydroxy-Ketones (Oxetones) 534
4. Hydroxy-Dialdehydes 535
5. Hydroxy- Aldehyde Ketones » . 536
xiv CONTENTS
PACK
6. Hydroxy-Ketones ........... 536
7. Dialdehyde Ketones 537
8. Aldehyde Diketones 537
9. Triketones 537
10. Dihydroxy-monocarboxylic Acids, 538; Monoamino-hydroxy-carboxylic Acids,
540 ; Monoamino-thio-carboxylic Acids, 541 ; Diamino-monocarboxylic
Acids, 542 ; Dihydroxy-olefine Monocarboxylic Acids .... 543
11, 12. Aldo-hydroxy-carboxylic Acids, and Hydroxy-keto-carboxylic Acids . 543
13. Aldehydo-ketone Carboxylic Acids -545
14. Diketo-carboxylic Acids .......... 546
15. Monohydroxy-dicarboxylic Acids.
A. Monohydroxy- Paraffin Dicarboxylic Acids . . . 548
Hydroxymalonic Acid Group
Hydroxysuccinic Acid Group
Aminosuccinic Acids
Hydroxyglutaric Acid Group
549
551
553
558
B. and C. Hydroxy-olefine Carboxylic Acids and Hydroxy-olefine Dicar-
boxylic Acids .......... 560
1 6. Aldodicarboxylic Acids. A. /3-Aldodicarboxylic Acids, 561. B. 7-Aldodi-
carboxylic Acids ........... 561
17. Ketone-dicarboxylic Acids, 562 ; Ketomalonic Acid Group, 562 ; Nitrogen
Derivatives of Mesoxalic Acid, 563 ; Ketosuccinic Acid Group, 564 ;
Nitrogen Derivatives of Oxalacetic Acid, 567 ; Ketoglutaric Acid Group,
568 ; Olefine- and Di-olefine-Ketone Dicarboxylic Acids . . . 571
Uric Acid Group: Urei'des or Carbamides of Aldehyd- and Keto-Mono-
carboxylic Acids, 572 ; Urei'des or Carbamides of Dicarboxylic Acids, 575 ;
Diureides, 580 ; Oxidation of Uric Acid, 584 ; Synthesis of Uric Acid, 585 ;
Conversion of Uric Acid into Xanthine, Guanine, Hypoxanthine and
Adenine, 587 j Synthesis of Heteroxanthine, Theobromine, and Paraxan-
thine 590
18. Tricarboxylic Acids : A. Saturated Tricarboxylic Acids, 592 ; B. Olefine
Tricarboxylic Acids .......... 594
VI. TETRAHYDRIC ALCOHOLS AND THEIR
OXIDATION PRODUCTS ... 595
1. Tetrahydric Alcohols .......... 596
2. Trihydroxyaldehydes ; 3. Trihydroxyke tones 597
4. Hydroxytriketones ........... 597
5. Tetraketones ......... . 597
6. Trihydroxy-monocarboxylic Acids ..... . 598
7. Dihydroxyketo-monocarboxylic Acids '. 598
8. Hydroxydiketo-carboxylic Acids .... 598
9. Triketo-monpcarboxylic Acids . . . . . . \ . 598
10. Dihydrpxy-dicarboxylic Acids : A. Malonic Acid Derivatives, 599 ; B.
Succinic Acid Derivatives, 599 ; Synthesis of Racemic Acid, 601 j C.
Glutaric Acid Derivatives, 605 ; D. Adipic Acid Derivatives and Higher
Homologues .......... 606
11. Hydroxy-keto-dicarboxylic Acids . . . 607
12. Diketone Dicarboxylic Acids , 607
13. Hydroxytricarboxylic Acids 6IO
14. Ketone Tricarboxylic Acids .' 612
15. Tetracarboxylic Acids : A. Paraffin Tetracarboxylic Acids,' 613 ;' B. Olefine
Tetracarboxylic Acids $j*
CONTENTS
XV
VII. THE PENTAHYDRIC ALCOHOLS OR PEN-
TITOLS AND THEIR OXIDATION PRODUCTS. 615
I. Pentahydric Alcohols, Pentitols .
2. Tetrahydroxyaldehydes, Aldopentoses
3. Tetrahydroxymonocarboxylic Acids
4. Trihydroxydicarboxylic Acids^ .
5. Dihydroxy-ketone Dicarboxylic Acids
6. Triketone Dicarboxylic Acids
7. Dihydroxytricarboxylic Acids
;
615
616
619
621
621
621
621
622
VIII. HEXA- AND POLY-HYDRIC ALCOHOLS
AND THEIR OXIDATION PRODUCTS . 622
I A. Hexhydric Alcohols, Hexahydroxyparaffins, Hexitols
622
2 A.
Heptahydric Alcohols .......... 624
Octahydric Alcohols 625
Nonohydric Alcohols .......... 625
Penta-, Hexa-, Hepta-, and Octo-TTydroxyaldehydes and Ketones . . 625
Pentahydroxyaldchydes, and 3A. Pentahydroxyketones, Hexoses, Dextroses
(Glucoses), Monoses 626
Aldohexoses 631
3 A. Ketohexoses 635
2 B. Aldoheptoses j 2 C. Aldo-octoses ; 2 D. Aldononoses .... 637
The synthesis of Grape-sugar or d-Dextrose, and of Fruit-sugar or d-Fructose. 637
A. The Space-Isomerism of the Pentitols and Pentoses, the Hexitols and
Hexoses ........... 639
B. The Space-Isomerism of the Simplest Hexitols and the Sugar-Acids, the
Aldohexoses and the Gluconic Acids ...... 641
Derivation of the Space-formula for d-Dextrose or Grape-sugar . . 643
Derivation of the Configuration of d-Tartaric Acid .... 646
4. Hexaketones . . . . . H . . . . . 647
5. PolyhydroxymoHocarboxylic Acids ........ 647
A. Pentahydroxycarboxylic Acids ........ 647
B. Hexose Carboxylic Aeids, Hexahydroxymonocarboxylic Acids
C. Aldoheptose Carboxylic Acids, Heptahydroxycarboxylic Acids
D. Aldo-octose Carboxylic Acids, Octohydroxycarboxylic Acids
6. Tetrahydroxy- and Pentahydroxy-Aldehyde Acids
7. Monoketotetrahydroxycarboxylic Acids
8. Polyhydroxydicarboxylic Acids : A. Tetrahydroxydicarboxylic Acids, 652
B. Pentahydroxydicarboxylic Acids
9. Tctraketodicarboxylic Acids
10. Triketo-tricarboxylic Acids
1 1 . Hydroxyketotetracarboxylic Acids
12. Diketotetracarboxylic Acids
Appendix : Higher Polycarboxylic Ethyl Este;s
651
<5'
652
652
652
655
655
6.S5
£55
656
656
CARBOHYDRATES
656
A. Disaccharides ; Saccharobioses 657
B. Trisaccharides ; Saccharotrioses . . * . • • • • . 66l
C. Polysaccharides, 66 1 ; Nitrocellulose! 6^4
zvi CONTENTS
PAGX
ANIMAL SUBSTANCES OF UNKNOWN CONSTITUTION 665
Proteins, Albumins, 666 ; a Monamino-monocarboxylic Acids, 666 ; b Mon-
amino-dicarboxylic Acids, 666 ; c Hydroxamino-, Thioamino-, Diamino,
Imino-Acids 667
A. Glucoprote'ins ............ 671
B. Phosphoprotei'ns ........... 672
C. Gelatin (Derivatives of Intercellular Materials) 673
D. Haemoglobins, 674 ; Chlorophyll .... . 675
E. Biliary Substances ........ . 676
F. Unorganized Ferments or Enzymes .... . 677
INDEX , , 679
A TEXT-BOOK
OF
ORGANIC CHEMISTRY
INTRODUCTION
WHILST inorganic chemistry was developed primarily through the
investigation of minerals, and was in consequence termed mineral
chemistry, it may be said that the development of organic chemistry
was due to the study of products resulting from the alteration of plant
and animal substances. About the close of the eighteenth century
Lavoisier demonstrated that, when the organic substances present in
vegetable and animal organisms were burned, carbon dioxide and
water were always formed. It was this chemist also who showed that
the component elements of these bodies, so different in properties,
were generally carbon, hydrogen, oxygen, and, especially in animal
substances, nitrogen. Lavoisier further gave utterance to the opinion
that peculiarly constituted atomic groups, or radicals, were to be
accepted as present in organic substances ; whilst the mineral sub-
stances were regarded by him as the direct combinations of single
elements.
As it seemed impossible, for a long time, to prepare organic bodies
synthetically from the elements, the opinion prevailed that there
existed an essential difference between organic and inorganic sub-
stances, which led to the use of the names Organic Chemistry and
Inorganic Chemistry. The prevalent opinion was, that the chemical
elements in the living bodies were subject to other laws than those in
the so-called inanimate nature, and that the organic substances were
formed in the organism only by the intervention of a peculiar vital
force, and that they could not possibly be prepared in an artificial
way.
One fact sufficed to prove these rather restricted views to be un-
founded. The first organic substance artificially prepared was urea
(Wohler, 1828). By this synthesis chiefly, to which others were soon
added, the idea of a peculiar force necessary to the formation of organic
compounds was contradicted. All further attempts to separate
organic substances from the inorganic (the chemistry of the simple
and the chemistry of the compound radicals, p. 18) were futile. At
present we know that these do not differ essentially from each other ;
VOL. i. B
2 ORGANIC CHEMISTRY
that the peculiarities of organic compounds are dependent solely on
the nature of their essential constituent, Carbon ; and that many sub-
stances belonging to plants and animals can be prepared artificially
from the elements. Organic Chemistry is, therefore, the chemistry of
the carbon compounds. Its separation from the chemistry of the other
elements is necessitated only by practical considerations, on account
of the very great number of carbon compounds (about 120,000 : see
M. M. Richter's Lexikon der Kohlenstoffverbindungen), which far
exceeds those of all other elements put together. No other possesses
in the same degree the ability of the carbon atoms to unite with one
another to form open and closed rings or chains. The numerous
existing carbon nuclei in which atoms or atomic groups of other
elements have entered in the formation of organic derivatives have
arisen in this manner.
The impetus given to the study of the compounds of carbon has not
only brought new industries into existence, but it has caused the rapid
development of others of like importance to the growth and welfare
of the nation.*
The advances of organic chemistry are equally important to the
investigation of the chemical processes in vegetable and animal
organisms, a section of the subject known as Physiological Chemistry.
DETERMINATION OF THE COMPOSITION OF CARBON
COMPOUNDS
ELEMENTARY ORGANIC ANALYSIS
Most carbon compounds occurring in the animal and vegetable
kingdoms consist of carbon, hydrogen, and oxygen, as was demonstrated
by Lavoisier, the founder of organic elementary analysis. Many, also,
contain nitrogen, and on this account these elements are termed
Organogens,\ whilst sulphur and phosphorus are often present. Almost
all the elements, non-metals and metals, may be artificially introduced
as constituents of carbon compounds in direct union with carbon.
The number of known carbon compounds is exceedingly great (see
above). The general procedure, therefore, of isolating the several
compounds of a mixture, as is done in inorganic chemistry in the
separation of bases from acids, is impracticable, and special methods
have to be devised. The task of elementary organic analysis is to
determine, qualitatively and quantitatively, the elements of a carbon
compound after it has been obtained in a pure state and characterized
by definite physical properties, such as crystalline form, specific
gravity, melting point, and boiling point. Simple practical methods
for the direct determination of oxygen do not exist ; its quantity is
usually calculated by difference, after the other constituents have been
found.
* Wirthschaftliche Bedeutung chemischer Arbeit, von H. Wichelhaus, 1893.
t This word is retained here from the German, but is not in general use in
English chemical language. (Translator's note.)
DETERMINATION OF CARBON AND HYDROGEN
DETERMINATION OF CARBON AND HYDROGEN
The presence of carbon in a substance is shown by its charring when
ignited out of contact with air. In general its quantity, as also that of
the hydrogen, is ascertained by combustion. The substance is mixed
in a glass tube with copper oxide and heated, or the vapour of the
substance is passed over red-hot copper oxide. The cupric oxide gives
up its oxygen and is reduced to metallic copper, whilst the carbon burns
to carbon dioxide, and the hydrogen to water. In quantitative
analysis, these products are collected separately in special apparatus,
and the increase in the weight of the latter determined. Carbon and
hydrogen are always simultaneously determined in one operation.
The details of the quantitative analysis are fully described in the text-
books of analytical chemistry.* It is only necessary here, therefore,
to outline the methods employed. Liebig' s name is especially associ-
ated with the elaboration of these methods (Pogg. A. 1831, 21, i).
Usually the combustion is effected by the aid of copper oxide or fused and
granulated lead chromate in a tube of hard glass, fifty to seventy centimetres long
(depending upon the greater or less volatility of the organic body). Substances
which burn with difficulty should be mixed with finely divided cupric oxide,
finely divided lead chromate, or with cupric oxide to which potassium bichromate
has been added.
The combustion tube is drawn into a point, and the contracted end given a
bayonet-shape (Liebig), or it is open at both ends (Glaser, A. Suppl. 7, 213).
Cloez has also suggested the use of an iron tube (Z. anal. Ch. 2, 413).
The tube is placed in a suitable furnace, which formerly was heated by a char-
coal fire, but at present gas is usually employed (A. W. Hofmann, A. 90, 235 ; 107,
37; Erlenmeyer, Sr., A. 139, 70; Glaser, I.e.; Anschutz and Kekule, A. 228,
301 ; Fuchs, B. 25, 2723). Recently electric heating has been adopted with
success (comp. B. 39, 2263).
When the tube has been charged, the open end is attached to an apparatus
designed to collect the water produced in the combustion. The substances used
to retain the moisture are :
1. A U-tube filled with carefully purified calcium chloride, which has been
dried at 180° C.
2. Pure, concentrated sulphuric acid contained in a specially designed tube,
or pumice fragments, dipped in the acid, and placed in a U-tube (Mathesius,
Z. anal. Ch. 23, 345).
3. Pellets of glacial phosphoric acid, contained in a U-tube. The vessel
intended to receive the water is in air-tight connection with the apparatus
designed to absorb the carbon dioxide. For the latter purpose a Liebig potash
bulb was formerly employed, but later that of Geissler came into use ; and very
many other forms have been recommended (B. 24, 271 ; C. 1900, 1, 1240).
U- tubes, filled with granulated soda-lime, are substituted for the customary
bulbs (Mulder, Z. anal. Ch. 1, 2).
When the combustion is finished, oxygen free from carbon dioxide is forced
into or drawn through the combustion-tube, air being substituted for it later, with
the precaution that the pieces of apparatus serving to dry the oxygen and air are
filled with the same material which was used for absorbing the water produced
by the combustion. As soon as the entire system is filled with air, the pieces of
apparatus employed for absorbing the water and carbon dioxide are disconnected
and weighed separately. The increase in weight of the apparatus in which the
water is collected represents the water resulting from the combustion of the
* Anleitung zur Analyse organischer Korper, J. Liebig. 2. Aufl. 1853.
Quantitative chemische Analyse, R. Fresenius. 6. Aufl., Bd. 2. Chemische
Analyse organischer Stoffe, von Vortmann. Die Entwicklung der organise hen
Elementaranalyse, M. Dennstedt, 1899.
4 ORGANIC CHEMISTRY
weighed substance, and the increase in the other the quantity of carbon dioxide.
Knowing the composition of water and carbon dioxide the quantity of carbon
and hydrogen contained in the burnt substance can readily be calculated in
percentage.
Fig. i represents one end of a combustion furnace of the type devised by
Kehult and Anschiitz (A. 228, 301). In it lies the combustion tube V. This is
connected with a Klinger calcium chloride tube, A \ B is a Geissler potash-bulb,
joined to a U-tube, C, one limb of which is filled with pieces of stick potash, and
the other with calcium chloride. G represents mica plates, which permit of a
careful observation of the flame. £ is a section of the iron tube (Modification,
C. 1903, 1, 609) in which the combustion tube V rests; T a side clay cover
placed over the mica strips ; D a clay cover for the top. R is the gutter into
which the gas-pipe, bearing the burners, is placed, and from which it can be
removed for repair, etc.
FIG. i.
Fig. i also shows, above the combustion tube, the anterior portion of a similar
tube V1, provided with a Bredt and Posth (A. 285, 385) calcium chloride tube A1,
in which the movement of a drop of water enables the analyst to determine the
rapidity of the combustion. B1 is a U-tube filled with soda-lime and provided
with ground-glass stoppers. C1 is a similar tube, rilled one-half with soda-lime
and one-half with calcium chloride.
Instead of oxidizing the organic substance with the combined oxygen of cupric
oxide or lead chromate, the method of Kopfer may be employed, in which platinum
black is made to carry free oxygen to the vapours of the substance. A simpler
combustion furnace may then be employed.
This method has been perfected by Dennstedt * and his co-workers. In his
" rapid combustion method " the substance is introduced into a small tube and
vapourized therefrom into a slow stream of oxygen. At the same time a more
rapid current of the gas is sent round the small containing tube and over the
heated contact substance (thin strips of platinum foil), so that the vapour of the
compound to be combusted is always in the presence of a large excess of oxygen,
f c£?mPanymS lllustration (FiS- 2) indicates clearly the arrangement (B. 33,
* Dennstedt, Anleitung zur vereinfachten Elementar-analyse, 2. Aufl.
Hamburg, 1906.
DETERMINATION OF CARBON AND HYDROGEN 5
Dudley recommends that the substance be placed in a boat and burned in a
platinum tube containing granular manganese dioxide in the anterior part (B. 21,
3172). Or the substance may be combusted in a drawn-out copper tube (C. 1898.
2,305).
Methods for the complete combustion of solid carbon compounds have been
worked out by W. Hempel, Krocker, as well as by Zuntz and Frentxel (B. 30, 202,
380, 605), by which the substance is completely burned in oxygen under pressure
io an autoclave.
Gaseous bodies can be analysed according to the usual gas analysis methods,
either with Bunsen's * apparatus, or with Hempcl' s,] when great accuracy is not
required. The volume of the gas or mixture of gases is measured after each
successive reaction with potassium hydroxide solution, fuming sulphuric acid,
alkaline pyrogallic acid and ammoniacal cuprous chloride. These reagents absorb
respectively carbon dioxide, the so-called heavy hydrocarbons (defines, acetylene,
aromatic hydrocarbons of the CnHfrt_t series), oxygen and carbon monoxide.
The gaseous residue, which may consist of nitrogen, hydrogen and methane, is
either exploded with oxygen and the contraction in volume measured both before
and after absorption of the carbon dioxide formed ; or else the two combustible
gases may be separately dealt with, the hydrogen being absorbed by paladium
FIG. 2.
black and the methane being led over incandescent platinum. A complete
separation of the ethylene hydrocarbons from those of the benzene series has
often been attempted, but the results have not been satisfactory.
When nitrogen is present in the substances burned, its oxides are sometimes
produced, which have to be reduced to nitrogen. This may be effected by con-
ducting the gases of the combustion over a layer of metallic copper filings, or a
roll of copper gauze placed in the front portion of the combustion tube. The
latter, in such cases, should be a little longer than usual. The copper, which has
been previously reduced in a current of hydrogen, often includes some of the gas
which, on subsequent combustion, would yield water. To remedy this, the copper
after reduction is heated in an air-bath or, better, in a current of carbon dioxide
or to 200° in a vacuum. Its reduction by the vapours of formic acid or methyl
alcohol is more advantageous ; this may be done by pouring a small quantity of
these liquids into a dry test tube and then suspending in them the roll of copper
heated to redness ; copper thus reduced is perfectly free from hydrogen.
It is generally unnecessary to use a copper spiral when the combustions are
carried out in open tubes.
If the substance contains chlorine, bromine or iodine, copper halides are formed,
which, being volatile, would pass into the calcium chloride tube. In order to
avoid this a spiral of thin copper, or better, silver foil is introduced into the front
* Bunsen, Gasometrische Methoden, 2. AufL Braunschweig, 1877.
t Hempel, Gasometrische Methoden, Braunschweig, 1900. Winkler, Ga*»
analyze, Freiberg, 1901.
6 ORGANIC CHEMISTRY
part of the tube. When the organic compound contains sulphur a portion of the
latter will be converted into sulphur dioxide (during the combustion with cupric
oxide), which may be prevented from escaping by introducing a layer of lead
peroxide (Z. anal. Ch. 17, i). Or lead chromate may be substituted for the cupric
oxide, which would convert the sulphur into non-volatile lead sulphate. In the
combustion of organic salts of the alkalies or alkaline earths, a portion of the
carbon dioxide is retained by the base. To prevent this and to expel the CO2,
the substance in the boat is mixed with potassium bichromate or chromic oxide
(B. 13, 1641).
An organic substance, containing nitrogen, sulphur, chlorine or bromine, can
be analysed by Dennstedt's method (see above, Fig. i). It is mixed with pure
lead peroxide and placed in a boat of special shape in the front part of the tube.
The temperature is then raised to about 320°. The nitrogen, sulphur, and halogens
are held back in the form of lead compounds, whilst the carbon and hydrogen pass
away as carbon dioxide and water, and are estimated in the usual way.
When carbon alone is to be determined this can be effected, in many instances,
in the wet way, by oxidation with chromic acid and sulphuric acid (Messinger,
B. 21, 2910 ; compare A. 273, 151).
DETERMINATION OF NITROGEN
In many instances, the presence of nitrogen is disclosed by the
odour of burnt feathers when the compounds under examination are
heated. Many nitrogenous substances yield ammonia when heated with
alkalies (or, better still, with soda-lime). A simple and very delicate test
for the detection of nitrogen is the following : the substance is heated
in a test tube with a small piece of sodium or potassium, or, when the
substance is explosive, with the addition of dry soda. Potassium
cyanide is produced, accompanied perhaps by a slight detonation.
The residue is treated with water ; to the filtrate, ferrous sulphate
containing a ferric salt is added, and then a few drops of potassium
hydroxide ; the mixture is then heated, and finally an excess of hydro-
chloric acid is added. An undissolved, blue-coloured precipitate
(Prussian blue), or a bluish-green coloration, indicates the presence
of nitrogen in the substance examined.
Nitrogen is determined quantitatively : (i) as nitrogen, by the
method of Dumas ; (20) as ammonia, by the ignition of the material
with soda-lime (method of Will and Varrentrap) ; (zb) as ammonia,
by heating the substance with sulphuric acid according to the direc-
tions of Kjeldahl.
i. Dumas' Method. — The substance, mixed with cupric oxide, is burned in a
tube of hard glass in the anterior end of which is a layer of metallic copper which
serves for the reduction of the oxides of nitrogen. The tube is filled with
carbon dioxide, obtained by heating either dry, primary sodium carbonate or
magnesite, contained in the posterior and closed end of the tube. It can also be
filled from a carbon dioxide apparatus of the type recommended by Kreusler
(Z. anal. Ch, 24, 440), in which case an open tube is used. A more practicable
method of procedure consists in evacuating the tube, previous to the combustion,
by means of an air-pump, and filling each time with carbon dioxide (A. 233, 330,
note) ; or the air may be removed by means of a mercury pump (Z. anal. Ch. 17,
409).
When the combustion is ended, excess of carbon dioxide is employed to sweep
all the nitrogen from the combustion tube into the graduated tube or azotometer,
which may have one of a variety of forms (Zulkowsky, A. 182, 296 ; B. 13, 1099 ;
Schwarz, B. 13, 771 ; Ludwig, B. 13, 883 ; H. Schiff, B. 13, 885 ; Staedel, B. 13,
2243 ; Groves, B. 13, 1341 ; Ilinski, B. 17, 1348). The potassium hydroxide in
the graduated vessel absorbs all the disengaged carbon dioxide, and only pure
nitrogen remains.
DETERMINATION OF NITROGEN 7
Given the volume Vt of the gas, the barometric pressure p and the vapour-
pressure s of the potassium hydroxide (Wullner, Pogg. A. 103, 529; 110, 564) at
the temperature t of the surrounding air, the volume V0 at o° and 760 mm. may be
easily deduced :
.
G =
760 (1+0-003665*)
ight of i
ght in gra
VX£-*)
ultiply V0 by 0*0012507, the weight of I c.c. of nitrogen at o° and 760 mm., and
the product will represent the weight in grams of the observed volume of nitrogen :
760 (1+1-0036650
from which the percentage of nitrogen in the substance analysed can easily be
calculated.
Instead of reducing the observed gas volume V, from the observed barometric
pressure and the temperature at the time of the experiment, to the normal pressure
of 760 mm. and the temperature of o° (" N.T.P."), the reduction may be more
readily effected by comparing the observed volume of gas or vapour with the
expansion of a normal gas- volume (100) measured at 760 mm. and o°. For this
purpose the equation V0=V.^^ is employed, in which v represents the changed
normal volume (100). The gas-volumometer recommended by Kreusler (B. 17,
30) and Winkler (B. 18, 2534), or the Lunge nitrometer (B. 18, 2030 ; 23, 440 ;
24, 1656, 3491 ; /. A . Muller, B. 26, R. 388) will answer very well for this purpose.
Or the nitrogen may be collected in a gas-baroscope, and its weight calculated from
the pressure of a known constant volume of nitrogen (B. 27, 2263).
Frankland and Armstrong conduct the combustion in a vacuum, and dispense
with the layer of metallic copper in the anterior portion of the tube. If any nitric
oxide is formed it is collected together with the nitrogen, and is subsequently
removed by absorption (B. 22, 3065).
Consult Hempel (Z. anal. Ch. 17, 409) ; E. Pfluger (ibid., 18, 296) ; and
Jannasch and V. Meyer (A. 233, 375), for methods by which carbon, hydrogen,
and nitrogen are determined simultaneously.
See Gehrenbeck (B. 22, 1694) when nitrogen and hydrogen are to be estimated
simultaneously, in cases where the carbon was determined in the wet way, as by
Messinger's method.
For the simultaneous determination of carbon and nitrogen, see Klingemann
(A. 275, 92).
2. Will and Varrentrap's Method. — When most nitrogenous organic com-
pounds (nitro-derivatives excepted) are ignited with alkalies, all the nitrogen
is eliminated in the form of ammonia gas. The weighed, finely pulverised sub-
stance is mixed with about 10 parts soda-lime, and placed in a combustion tube
about 30 cm. in length, which is then filled with soda-lime. At the open end of
the tube there is connected a bulb apparatus, containing dilute hydrochloric acid.
The anterior portion of the tube in the furnace is first heated, then that containing
the mixture. In order to carry all the ammonia into the bulb, air is passed through
the tube, after the fused-up end has been broken. The ammonium chloride in the
hydrochloric acid is precipitated with platinic chloride, as ammonium-platinum
chloride (PtG4 . 2NH4C1); the precipitate is then ignited, and the residual Pt
weighed ; i atom of Pt corresponds to 2 molecules of NH3 or 2 atoms of nitrogen.
Or, having employed a definite volume of acid in the apparatus, the excess
after the ammonia absorption may be determined volumetrically, using fluorescein
or methyl orange as an indicator.
Generally, too little nitrogen is obtained by this method, because a portion of
the ammonia undergoes decomposition. This is avoided by adding sugar to the
mixture of substance and soda-lime, and by avoiding heating the tube too strongly
(Z. anal. Ch. 19, 91). Further, the tube must be filled with soda-lime as com-
pletely as possible (Z. anal. Ch. 21, 278).
The method of Will and Varrentrap is made more widely applicable by the
addition of reducing substances to the soda-lime. Goldberg (B, 16, 2549) recom-
mends a mixture of soda-lime (100 parts), stannous sulphide (100 parts), and sulphur
(20 parts) ; this he considers especially advantageous in estimating the nitrogen
of nitro- and azo-compounds. For nitrates, Arnold (B. 18, 806) employs a mixture
of soda-lime (2 parts), sodium thiosulphate (i part), and sodium formate (i part).
8 ORGANIC CHEMISTRY
3. Kjeldahl's Method.— The substance is dissolved by heating it with con-
centrated sulphuric acid. This decomposes the organic matter and converts the
nitrogen into ammonia. After the liquid has been diluted with water and cooled,
and a small quantity of potassium permanganate has been added, the ammonia
is expelled from it by boiling with sodium hydroxide (Z. anal. Ch. 22, 366). This
method is well adapted for the determination of the nitrogen of plants and animal
substances (compare urea). When the nitrogen in nitro- and cyanogen compounds
is to be estimated, sugar must be added ; and in the case of nitrates, benzoic acid.
The addition of mercury or mercuric oxide is highly advantageous (B. 18, R.
199, 297 ; 29, R. 146). Pyridine and quinoline cannot be analysed by this
method (B. 19, R. 367, 368).
The Kjeldahl method for the determination of nitrogen has rapidly come into
favour on account of the simplicity of the operation and of the apparatus, and of
the possibility to carry out a number of determinations simultaneously. A large
number of modifications of the method have been proposed to render it generally
applicable (B. 27, 1633, 28, R. 937 ; C. 1898, 2, 312).
NOTE. — The nitrogen of nitro- and nitroso-compounds can be determined
indirectly with a standardized solution of stannous chloride. The latter converts
the groups NO2 and NO into the amide group, and is itself converted into an
equivalent quantity of stannic chloride. This can be determined by titrating
the excess of stannous salt with an iodine solution (Limpricht, B. 11, 40).
DETERMINATION OF THE HALOGENS, SULPHUR, AND
PHOSPHORUS
Qualitative Analysis : Substances containing chlorine, bromine and
iodine burn with a flame having a green-tinged border. The following
reaction is exceedingly delicate. A little cupric oxide is first ignited
on a platinum wire, then some of the substance to be examined is
placed upon it, and the whole is heated in the non-luminous gas flarne,
which is coloured an intense greenish-blue if a halogen is present.
A more definite test is to ignite the substance in a test tube with burnt
lime (free from halogens), dissolve the mass in nitric acid, and then
to add silver nitrate to the filtered solution.
The presence of sulphur can frequently be detected by fusing the
substance with potassium hydroxide ; potassium sulphide results,
which produces a black stain of silver sulphide on a clean piece of
silver ; or by heating the substance with metallic sodium and testing
the aqueous filtrate for sodium sulphide with sodium nitro prusside :
if present, a purple-violet coloration is produced. When testing for
sulphur and phosphorus, the substance is oxidized with a mixture of
potassium nitrate and potassium carbonate ; the resulting sulphuric
and phosphoric acids are sought for by the usual methods.
Quantitative Analysis : A hard glass tube, closed at one end, and about
33 cm. in length, containing a mixture of tlie substance with ch'orinc- free lime, is
heated. After cooling, its contends are dissolved in dilute nitiic acid, the solution
is filtered and silver i_itrate is addtd to precipitate the halogen.
The decomposition is easier if ircte?.d cf lime a mixture of lime with \ part
sodium carbonate, or i part sodium cz.rboz9.te with 2 parts potassium nitrate is
employed ; and in the case of sutetMic?s vc!atL%,'ng \vith difficulty, a platinum
or porcelain crucible, heated over a ges lamp, can be used (Vclhatd, A. ISO, 40 ;
Scheff, A. 195, 293). With compounds crn':air'rg icdme, iodic acid may form,
which, after solution of the mass, may be reduced by sulphurous acid. The
volumetric method of Volhard (A. 190, i) for estimating halogens, employing
ammonium thiocyanate as indicator, is strongly to be recommended in place of
the customary gravimetric method.
DETERMINATION OF THE MOLECULAR FORMULA 9
The same decomposition can also be effected by ignition with iron, ferric oxide,
and sodium carbonate (E. Kopp, B. 10, 290).
The substances containing the halogens may also be burned in oxygen. The
gases are conducted ever platini/ed quartz sand, and the products collected in
suitable solutions (Zulkowsky, B. 18, R. 648).
The substances may be buiued in a current of oxygen, and the products con-
ducted through a layer of pure granular lime (or soda-lime) raised to a red heat.
Later, the lime is dissolved in dilute nitric acid, and the halogens, the sulphuric
acid and the phosphoric acid may then be estimated. Arsenic may be determined
similarly (Brugelmann, Z. anal. Ch. 15, 1 ; 16, i). Satier recommends collecting
the sulphur dioxide, formed in the combustion of the substance, in hydrochloric
acid containing bromine (ibid. 12, 178). See also the simultaneous estimation of
halogens and sulphur in the presence of carbon and hydrogen, by Dennstedt's
method (p. 4).
To determine sulphur and the halogens by the method suggested by Klason
(B. 19, 1910), the substance is oxidized in a current of oxygen charged with
nitrous vapours, and the products of combustion are conducted over rolls of
platinum foil. Consult Poleck (Z. anal. Ch. 22, 171) for the estimation of the
sulphur contained in coal gas.
A method of frequent use for the determination of the halogens,
sulphur, and phosphorus in organic bodies is that of Carius (Z. anal.
Ch. 1, 240 ; 4, 451 ; 10, 103) ; Linnemann (ibid. 11, 325) ; Obermeyer
(B. 20, 2928).
The substance, weighed out in a small glass tube, is heated together
with concentrated nitric acid and silver nitrate to 150-300° C. in a
sealed tube, and the quantity of the resulting silver haloid (B. 28, R.
478, 864), sulphuric acid, and phosphoric acid determined. The
furnace of Babo (B. 13, 1219) is especially adapted for heating the
tubes. The results by this method are not always reliable (A. 223, 184).
The following method is more generally applicable for the estima-
tion of sulphur and the halogens : the substance is carefully heated in
a nickel crucible with a mixture of sodium and potassium carbonates
and sodium peroxide. After having been melted, the product of re-
action is dissolved in water and acidified with hydrochloric acid con-
taining bromine ; the sulphur is then precipitated as barium sulphate
(B. 28, 427 ; C. 1904, 2, 1622, etc.).
In many instances, the halogens may be separated by the action of
sodium amalgam on the aqueous solution of the substance, or by that
of sodium on the alcoholic solution. The quantity of the resulting
salt is determined in the filtered liquid (Kekule, A. Suppl. 1, 340;
comp. C. 1905, 1, 1273 ; B. 39, 4056).
Sulphur and phosphorus can often be estimated by the wet method.
The oxidation is effected by means of potassium permanganate and
alkali hydroxide, or with potassium bichromate and hydrochloric acid
(Messinger, B. 21, 2914).
DETERMINATION OF THE MOLECULAR FORMULA*
The results of elementary analysis are expressed as the percentage
composition of the substance thus examined ; then follows the deter-
mination of the molecular formula.
We arrive at the simplest ratio in the number of elementary atoms
* Die Bestimmung des Moleculargewichts in theoretischer und practischer
iehurig, von K. Windisch, 1892.
,
to ORGANIC CHEMISTRY
contained in a compound, by dividing the percentage numbers by the
respective atomic weights of the elements.
Thus, the analysis of lactic acid gave the following percentage composition :—
Carbon ........ 4°'° Per cent-
Hydrogen ....... 6-6 ,,
Oxygen ....... 53*4 » (bY difference)
lOO'O
Dividing these numbers by the corresponding weights (C = 12, H =i, O = iC)..
the following quotients are obtained : —
3.3 = ,
Therefore, the ratio of the number of atoms of C, H, and O, in lactic acid, is as
3-3 : 6'6 : 3-3, or i : 2 : i. The simplest atomic formula, then, would be CH2O ;
however, it remains undetermined what multiple, if any, of this formula expresses
the true composition. The lowest formula of a compound, by which is expressed
the ratio of the atoms of other elements to those of the carbon atoms, is an
empirical formula. Indeed, we are acquainted with different substances having
the empirical formula CH2O, for example, formaldehyde, CHaO; acetic acid,
CaH4O2; lactic acid, C3H6O3; dextrose, C,HltO6, etc.
With compounds of complicated structure, the derivation of the
simplest formula is, indeed, unreliable, because various formulae may
be deduced from the percentage numbers on account of the possible
errors of observation. The true molecular formula, therefore, can
only be ascertained by some other means. Three courses of procedure
are open to us. First, the study of the chemical reactions, and the
derivatives of the substance under consideration ; second, the deter-
mination of the vapour density of volatile substances ; and third, the
examination of certain properties of the solutions of soluble substances.
(i) Determination of the Molecular Weight by the Chemical Method
This is applicable to all substances, but does not invariably lead to
definite conclusions. It consists in preparing derivatives, analysing
them and comparing their formulae with the supposed formula of the
original compound. The problem becomes simpler when the sub-
stance is either a base or an acid. Then it is only necessary to prepare
a salt, determine the quantity of metal combined with the acid, or of
the mineral acid in union with the base, and from this to calculate
the equivalent formula. A few examples will serve to illustrate this.
The silver salt of lactic acid may be prepared (the silver salts are easily obtained
pure, and generally crystallize without water) and the quantity of silver in it
determined ; 54-8 per cent, of silver will be found. As the atomic weight of
silver == 1077, the amount of the other constituent combined with one atom of
Ag in silver lactate, may be calculated from the proportion —
54'8 : (ioo - 54-8) : : 1077 : x
x — 89-0.
Granting that lactic acid is monobasic, that in the silver salt one atom of hydrogen
is replaced by silver, it follows that the molecular weight of the free (lactic) acid
must = 89 + i = 90. Consequently the simplest empiric formula of the acid,
CHaO = 30, must be tripled. Hence, the molecular formula of the free acid is
c.H.o. = 90 : ^
C3 =36 . . . 40-0
H,= 6 ... 67
0,=48 . . . 53-3
9O lOO'O
DETERMINATION OF THE MOLECULAR WEIGHT n
In studying a base, the platinum double salt is usually prepared. The con-
stitution of these double salts is analogous to that of ammonium-platinum chloride
— PtCl4 . 2(NH,HC1) — the ammonia being replaced by the base. The quantity of
platinum in the double salt is determined by ignition, and calculating the quantity
of the constituent combined with one atom of Pt (195*2 parts). From the number
found, six atoms of chlorine and two atoms of hydrogen are subtracted, and the
result is then divided by two ; the final figure will be the equivalent or molecular
weight of the base.
Or, the substance is subjected to reactions of various kinds, e.g. the substitu-
tion of its hydrogen by chlorine. The simplest formula of acetic acid, as described
above, is CH2O. By substitution three acids can be obtained from acetic acid.
These, upon treatment with nascent hydrogen, revert to the original acetic acid.
They are —
C2H3C1O2 — Monochloracetic Acid,
C2H2C12O2— Dichloracetic Acid, and
C2HC13O2 — Trichloracetir. Acid.
Consequently, there must be three replaceable hydrogen atoms in the acid.
This would lead us to the formula C2H4O2 for it. (Comp. also Ladenburg : Die
Theorie der aromatischen Verbindungen (1876), p. 10.)
Knowing the molecular value of an analysed compound, it will
often be necessary to multiply its empirical formula to obtain one which
will express the number of atoms contained in the molecule. This
will be the empirical molecular formula.
(2) Determination of the Molecular Weight from the Vapour
Density
This method is limited to those substances which can be volatilized
without undergoing decomposition. It is based upon the law of
Avogadro, according to which equal volumes of all gases and vapours at
like temperature and like pressure contain an equal number of molecules.
The molecular weights are, therefore, the same as the specific gravities.
As the specific gravity is compared with H = I, and the molecular
weights with H2 = 2, we ascertain the molecular weights by multiplying
the specific gravity by 2. Should the specific gravity be referred
to air = i, then the molecular weight is equal to the specific gravity
multiplied by 28-86 (since air is 14-43 times heavier than hydrogen).
Molecular Weight. Specific Gravity.
Air — 14-43 i
Hydrogen . . . H2 = 2 i 0-0693
Oxygen . . . O2 = 3174 I5'&7 -riodo
Water .... H2O = 17-87 8-93 0*622
Methane . . . CH4 = 15-97 7-98 o'553
Experience has shown that the results arrived at by the chemical
method and those obtained from the vapour density — are almost
always identical. If a deviation should occur, it is invariably in con-
sequence of the substance undergoing decomposition, or dissociation,
in its conversion into vapour.
Two essentially different methods are employed in determining the
vapour density. According to one, by weighing a vessel of known
capacity filled with vapour, the weight of the latter is ascertained —
method of Dumas and oi Bunsen; in accordance with the other, a weighed
quantity of substance is vaporized and the volume of the resulting
vapour determined. In the latter case the vapour volume may be directly
12
ORGANIC CHEMISTRY
measured— methods of Gay-Lussac and A. W. Hofmann t or it may be
calculated from the equivalent quantity of a liquid expelled by the
vapour— displacement methods. The first three methods, of which a
fuller description may be found in more extended text-books,* are
seldom employed at present in laboratories, because the method of
V. Meyer, which is characterised by simplicity in execution, affords
sufficiently accurate results for all ordinary purposes.
Method of Victor Meyer. — Determination of vapour density by displacement of air
(B. 11, 1867, 2253). A weighed quantity of substance is vaporized in an enclosed
space, and the volume of air which it displaces is measured. Fig. 3 represents the
apparatus constructed for this purpose. It consists of a narrow glass tube, ending
in a cylindrical vessel, A . The upper, somewhat enlarged opening, B, is closed with
an india-rubber stopper. A short capillary side tube, C, conducts the displaced
air into the water- bath, D. The substance is weighed out in a small glass tube
provided with a stopper, and is vaporized in A, the
escaping air being collected in the eudiometer, E. The
vapour-bath, used in heating A, consists of a wide
glass cylinder, F (B. 19, 1862), f whose lower, some-
what enlarged end, is closed and filled with a liquid
of known boiling point. The liquid employed is
determined by the substance under examination ; its
boiling point must be above that of the latter.
Some of the liquids in use are water (100°), xylene
(about 140°), aniline (184°), ethyl benzoate (213°),
amyl benzoate (261°), and diphenylamine (310°).
The vapour density, S, equals the weight of the
vapour, P (the same, naturally, as the weight of the
substance employed), divided by the weight of an
equal volume of air, P' —
•4
i c.c. of air at o° and 760 mm. pressure weighs
0-001293 gram. The air volume Vt, found at the
observed temperature is under the pressure p — s, in
which p indicates the barometric pressure and s the
tension of the aqueous vapour at temperature t. The
weight then would be —
P'= 0-001293.
i -f 0-00367^ 760 "
Consequently the vapour density sought is—
o-oo367/)76o
=s)'
FIG. 3.
0-001293
The displaced air may be collected in the gas-baroscope
(compare p. 7). (B. 27, 2267.)
V. Meyer's method yields results that are sufficiently
accurate in practice, because in deducing the molecular
weight from the vapour density, relatively large numbers are considered and
the little differences do not come into consideration. A greater inaccuracy
may arise in the method of introducing the substances into the apparatus
because air is apt to enter the vessel. L. Meyer (B. 13, 991), Piccard (B. 13,
1080), Mahlmann (B. 18, 1624), and V. Meyer and Biltz (B. 21, 688) have
suggested various devices to avoid this source of error. To test the liability to
decomposition of the substance at the temperature of the experiment, a small
* Consult Handworterbuch der Chemie, Ladenburg, Bd. 8, 244.
t It is simpler to make the reduction to 760 mm. o° by comparison with a
normal volume (p. 7).
DETERMINATION OF THE MOLECULAR WEIGHT 13
>rtion of it may be heated in a glass bulb drawn out to a long point (B. 14,
[466).
Substances boiling above 300* are heated in a lead-bath (B. 11, 2255). Porce-
i vessels are used when the temperature required is so high as to melt glass,
id the heating is then carried out in a Perrot's gas oven (B. 12, 1112). Where air
affects the substances in vapour form, the apparatus is filled with pure nitrogen
(B. 18, 2809 ; 21, 688). If the substances under investigation attack porcelain,
tubes of platinum are substituted for the latter, which are enclosed in glazed
porcelain tubes, and then heated in furnaces (B. 12, 2204 ; Z. phys. Ch. 1, 146 ;
B. 21, 688). This form of apparatus allows of the simultaneous determination
of temperature (B. 15, 141 ; Z. phys. Ch. 1, 153).
For modifications in displacement methods of determining the density of gases,
consult V. Meyer (B. 15, 137, 1161, 2771); Langer and V. Meyer, Pyrotechnische
Untersuchungen, 1885; Crafts (B. 13, 851; \\, 356; 16, 457). For air-baths
and regulators see L. Meyer (B. 16, 1087 ; 17, 478).
Modifications of the displacement method, adapted for work under reduced
pressure, have been proposed by La Coste (B. 18, 2122), Schatt (B. 22, 140, with
bibliography ; B. 27, R. 604), Eyckmann (B. 22, 2754), V. Meyer and Demulh
(B. 23, 311) ; Richards (B. 23, 919, note), Ncuberg (B. 24, 729, 2543).
For further methods see Nilson and Pettcrsson (B. 17, 987 ; 19, R. 88 ; J.
pr. Ch. 83, i) ; Biltx (B. 21, 2767).
(3) Determination of the Molecular Weight of Substances when in
Solution
i. By Means of Osmotic Pressure. — According to the theory of
solutions developed by van 't Hoff (Z. phys. Ch. 1, 481; 3, 198;
B. 27, 6),* chemical substances, when in dilute solution, behave as
though they were in the form of a gas or vapour ; so that the laws of
Boyle and Gay-Lvssac, and the hypothesis of Avogadro, apply also to
dilute solutions. We know that the gas particles exert pressure, and it is
also true that the particles of compounds, when dissolved, exert a pres-
sure, which is directly expressed or shown by osmotic phenomena, and
hence it is termed osmotic pressure. This pressure is equal to that
which would be exerted by an equal amount of the substance, if it
were converted into a gas, and occupied the same volume, at the same
temperature, as the solution. Solutions containing molecular quan-
tities of different substances exert the same osmotic pressure. It is,
therefore, possible, as in the case of gas pressure, to deduce directly the
molecular weight of the substance in solution from its osmotic pressure.
Pfeffer has determined osmotic pressure by means of artificial cells having
semi-permeable walls. If suitably modified, this method promises to be of wide
applicability (Ladenburg, B. 22, 1225).
The plasmolytic method of de Vries for the determination of osmotic pressure,
is based upon the use of living plant-cells, in place of which Hamburger employed
red blood corpuscles (Z. physik. Ch. 2, 415 ; 14-, 424).
The molecular weight is most simply calculated by the general formula for
gases : pv «= RT, in which R represents a constant, and T the absolute tempera-
ture, calculated from — 273*. If this equation is also to include the hypothesis
of Avogadro (that the molecular weights of gases or dissolved substances occupy
the same volume at like temperature and pressure), then molecular quantities
of the substances must always be taken into consideration. The constant equals
84000 for gram-molecular weights (2 grams hydrogen, or 3174 grams oxygen)
* See Ostwald's Grundriss der allgemeinen Chemie, 2. Aufl. 1890; Lotha*
Meyer-Rimbach Grundziige der theoretischen Chemie, 4. Aufl. 1907.
i4 ORGANIC CHEMISTRY
at the temperature o° (or 273°), and the pressure (gas or osmotic pressure) of
76 cm. of mercury.
p . v = 84000 . T.*
where v represents the volume corresponding to the gram-molecular weight
TVT
(y = — ,in which a is the weight in grams of i c.c. of the gas, or dissolved sub-
stance, contained in i c.c. of the solution). After substitution the formula reads :
p. 13-59 x — = 84000 (273 -f t),
with the four variables p, M, a and t. If three of these be given the fourth
can be calculated. Consequently, the molecular weight M is found from the
formula —
a . 84000(273 + t) = a . 618(273 + Q .
p.*3'59 P
2. From the Lowering of the Vapour Pressure or the Raising of the Boiling
Point. — The lowering of the vapour pressure of solutions is closely connected
with osmotic pressure. Solutions at the same temperature have a lower
vapour pressure (/') than the pure solvent (/), and consequently boil at a
higher temperature than the latter. The lowering in pressure (f—ff) is in pro-
portion to the quantity of the substance dissolved (Wullner), according to the
equation *—j- =k g, in which k represents the " relative lowering of the vapour
pressure " ( ^ ) *or * Per cent- solutions, and g their percentage content.
If the lowering be referred not to equal quantities, but to molecular quantities
of the substances dissolved, it is found that equi-molecular solutions (those con-
taining molecular quantities of the different substances in equal amounts in
the same solvent) show equal lowering — the molecular vapour pressure lowering
is constant : —
M-fcC-C
M. — f~~ *"
Again, on comparing the relative lowering of vapour pressure in different
solvents, it will be found also that they are equal, if equal amounts of the sub-
stances are dissolved in molecular quantities of the solvent. In its broadest
sense the law would read : The lowering of vapour-pressure is to the vapour-
pressure of the solvent (/) as the number of molecules of the dissolved body («)
is to the total number of molecules (n -f N) : —
/-/'
G —
Substituting ^ and ^ (g and G represent the weight quantities of the sub-
stance and the solvent ; m and M are their molecular weights), for n and N, the
molecular weights, can readily be calculated.
F. M. Raoult (1887) discovered these relationships and put them forward
as being empirical. Soon after van 't Hoff (Z. phys. Ch. 3, 115) deduced them
theoretically from the osmotic pressure. • They are only of value for substances
non- volatile as compared with the solvent, or for such as volatilize with difficulty,
and show the same abnormalities as are observed with osmotic pressure and
depression in the freezing point.
The methods for the determination of vapour pressure are yet too little known
and primitive in their nature to be applied in the practical determination of
molecular weights (B. 22, 1084 ; Z. phys. Ch. 4, 538). Far more simple and
exact is the determination of the rise in the boiling point, which corresponds with
ihis(Beckmann, Z. phys. Ch. 4, 539 ; 6, 437 ; 8, 223 ; 15, 656 ; B. 27, R. 727 ;
28, R. 432).
* R = -^-; p = 1033 = 76 x 13-59 (sp. gr. of mercury) ; v = 22196 = 31-74
0-001430 (wt. of i c.c. of oxygen). R = IO33X22i96
273
DETERMINATION OF THE MOLECULAR WEIGHT 15
Method of Beckmann.— A tube, A (Fig. 4), is employed as the boiling
vessel, and is provided with two side tubes tl and tz. The substance under
examination is introduced through tl ; a condenser, N, is attached to t« and a
calcium chloride tube may be inserted at M. Garnets or fragments of platinum
are introduced into the
main tube, followed by
the solvent, and finally
the opening is closed
by a differential ther-
mometer (Beckmann,
Z. physik. Ch. 51, 329),
of which the bulb must
be completely covered
by the liquid. The boil-
ing tube is surrounded
with an air-bath consist-
ing of a mica cylinder,
g, and two glass-wool
plugs, hl and hz. When
dealing with liquids of
high boiling point the
air-bath may be re-
placed by a vapour-
bath made of glass or
porcelain, which is
charged with the same
liquid as that which is
employed as the solvent; otherwise the boiling tube may be heated directly on
an asbestos netting, LD, over a micro-burner. The boiling point of the pure
solvent is first read, and then again after a known quantity of the solute has
been introduced down the tube t. A rise of temperature is observed, and should
be taken after each of several successive additions of weighed quantities of the
solute.
A modification of the apparatus has been devised by Beckmann (Z.
physik. Ch. 44, 161) based on that of Sakurai and Landsberger (B. 31, 458 ; 36,
1555). In this form, the temperature of the solution is raised by passing into it
the vapour of the solvent, whereby continuous readings can be taken of the
boiling point of the solution of a constant weight of solute in an increasing quantity
of solvent. 5. Arrhenius has deduced a formula for the molecular rise in boiling
point, which is perfectly analogous to that of van 'tHoffioithe molecular depression
of the freezing point. The molecular rise is expressed by d=o-Q2 . — , in which
T represents the absolute boiling point, and w the heat of evaporation of the
solvent. Upon dissolving i gram-molecule of a substance, i.e. if the molecular
weight of the body is m, then m grams of it in 100 grams of solvent, the boiling
point will be raised d° ; upon dissolving p grams of the substance in 100 gr. of
solvent the rise \rill be d x° whence dt =d . — ; from which
FIG.
m = p. -j-
where
p = the weight (in grams) of the substance, dissolved in 100 grams of the
solvent,
(T2\
= 0'02. — 1,
dj= observed rise in boiling point.
The molecular rise of the boiling point in the case of ether is 2i'i°, of
chloroform 36-6°, and of acetic acid 25-3°.
3. From the Depression of the Freezing Point.— The mole-
cular weights of dissolved substances are accurately and readily
16 ORGANIC CHEMISTRY
deduced from the depression of the freezing points of their solutions.
Blagden in 1788, and Rudorff in 1861, found that the depression of
the freezing points of crystallizable solvents, or substances (as water,
benzene, and glacial acetic acid) is proportional to the quantity of
substance dissolved by them. The later researches of Coppet (1871),
and especially those of Raoult (1882), have established the fact that
when molecular quantities of different substances are dissolved in the
same amount of a solvent, they show the same depression in their
freezing points (Law of Raoult). If / represents the depression pro-
duced by p grams of a substance dissolved in 100 grams of the solvent,
the coefficient of depression - will be the depression for i gram of
substance in 100 grams of the solution.* The molecular depression is
the product obtained by multiplying the depression coefficient by
the molecular weight of the dissolved substances. This is a constant
for all substances having the same solvent : —
Raoult's experiments show the constant to have approximately
the following values : for benzene, 49 ; for glacial acetic acid, 39 ; for
water, 19. When the constant is known, the molecular weight is calcu-
lated as follows : —
M.cf
A comparison of the constants found for different solvents will disclose the
fact that they bear the same ratio to each other as the molecular weights— that
consequently the quotient obtained from the molecular depressions and molecular
weights is a constant value of about 0*62. It means, expressed differently, that
the molecule of any one substance dissolved in 100 molecules of a liquid lowers
the point of solidification very nearly o'62°.
These empirical laws, discovered by Coppet and Raoult, have been theoretically
deduced byGuldberg (1870) and van "t Hoff (1886) from the diminution of vapour
pressure and of osmotic pressure. The constant C is obtained for the various
T*
solvents, from the formula 0*02 — , where T indicates the absolute temperature
of solidification of the solvent, and w is its latent heat of fusion. In this way
van 't Hoff calculated the constants for benzene (53), acetic acid (38-8), and water
1 8 '9 (see above).
The laws just described can only be employed in their simple form
in the case of indifferent or but slightly chemically active substances.
Salts, strong acids, and bases (all electrolytes) behave unexpectedly
in that the depressions of freezing point, the change in osmotic pressure,
and the lowering of vapour pressure as found experimentally are all
greater than their calculated values ; the electrolytic dissociation
theory of Arrhenius (Z. phys. Ch. 1, 577, 631 ; 2, 491 ; B. 27, R. 542)
accounts for this by the assumption that the electrolytes have separated
into their free ions. However, even the indifferent bodies exhibit
many abnormalities — generally the very opposite of the ordinary.
These seem to be due to the fact that the substances held in solution
had not completely broken up into their individual molecules. The
•Arrhenius (Z. phys. Ch. 2, 493) expresses the content of solutions by the
weight in grams of the substances contained in TOO c.c. of the solution.
DETERMINATION OF THE MOLECULAR WEIGHT 17
most accurate results are obtained by operating with very dilute
solutions, and by employing glacial acetic acid as solvent. This dis-
sociates solids most readily.
Various forms of apparatus suitable for the above purpose,
and methods of working have been proposed by Auwers (B. 21,
711), Hotteman (B. 21, 860), Hentschel (Z. phys. Ch. 2, 307), Beck-
mann (Z. phys. Ch. 2, 638), Eykmann (Z. phys. Ch. 2, 964), Klobu-
kow (Z. phys. Ch. 4, 10), and Baumann and Fromm (B. 24, 1431).
Method of Beckmann. — A thick walled test tube, 2-3 cm. in
diameter, to which a side tube has been fused (Fig. 5), is partially
filled with 10-15 gm. of solvent, weighed to the nearest gram.
A platinum stirrer is inserted, which terminates at its upper
end in a platinized or enamelled iron ring. The freezing tube
is then closed with a stopper carrying a Beckmann thermometer
(p. 15). Above the iron ring of the stirrer is fixed a small
electromagnet, which is energized by the accumulators A at
periods determined
by the metronome
M. The stirrer is
thus kept continu-
ously in motion,
whilst the injurious
effect of the atmo-
spheric moisture is
avoided. The lower
part of the freezing
tube is fixed by
means of a cork
inside a wider tube
in order to prevent
a too rapid fall of
temperature when
the apparatus is
plunged into a
beaker containing a
freezing mixture.
When the solvent
chosen is acetic acid (solidifying about 16*) cold water may be employed ; for
benzene (solidifying about 5°), ice- water is suitable. The freezing
point of the solvent is then determined, by cooling it to 1-2° below
its solidifying point and then starting crystallization by stirring, or
by the introduction of scraps of platinum foil or by " inoculation "
with a crystal of the substance forming the ?olute. The thermometer
then suddenly rises a little, and the freezing point is taken to be that
at which the mercury remains constant for a little while. After
allowing the mass to thaw, a carefully weighed quantity of the solid
to be examined is introduced down the side tube, and allowed to
dissolve. The freezing point of the solution is then determined in
a similar manner to that just described (B. 28, R. 412 ; C. 1910,
I. 241 ; II. 361 ; Z. phys. Ch. 40, 192 ; 44, 169).
Eykmann's Method (A. 273, 98) requires phenol as the solvent
(melting about 38°), whereby considerable simplification is possible.
Its molecular depression is greater than that of benzene, and has
been calculated theoretically as being 76 (p. 16). Fig. 6 represents
the form of apparatus, which consists of a flask with two tubulures,
in one of which a thermometer is fixed, and over the other is placed
a ground-glass cap.
The investigations of Paterno and others show, contrary to earlier
observations, that when benzene is employed as the solvent the
carbon derivatives mostly yield normal results ; the exceptions being the
alcohols, phenols, acids, oximes, and pyrrole (B. 22, 1430 and Z. phys. Ch. 5, 94 ',
B. 27, R. 845 ; 28, R. 974)-
VOL. I. Q
FIG. 0.
i8 ORGANIC CHEMISTRY
Naphthalene may also be used for determinations of this kind ; van 't Hoff
gives its depression constant as being about 70 (B. 22, 2501 ; 23, R. i ; 24,
Consult B. 28, 804 for a method of determining molecular weights from the
decrease in solubility.
For the determination of molecular weight from molecular solution-volume, see
B. 29, 1023.
THE CHEMICAL CONSTITUTION OF THE CARBON COMPOUNDS
Early Theories. — The opinion that the cause of chemical affinity resided in elec-
trical forces was first expressed in the commencement of the last century, when the
remarkable decompositions of chemical bodies through the agency of the electric
current were discovered. It was assumed that the elementary atoms possessed
different electrical polarities, and that the elements were arranged in a series accord-
ing to their electrical behaviour. Chemical union depended on the equalization of
different electricities. The dualistic idea of the constitution of compounds was
a necessary consequence of this hypothesis. According to it, every chemical
compound was composed of two groups, electrically different, and these were
further made up of two different groups or elements. Thus, salts were viewed
as combinations of electro-positive bases (metallic oxides), with electro-negative
acids (acid anhydrides), and these, in turn, were held to be binary compounds of
oxygen with metals and non-metals. With this as basis there was constructed
the electro-chemical, dualistic theory of Berxelius, which almost exclusively domi-
nated chemical science in Germany until the beginning of 1860.
The principles predominating in inorganic chemistry were also applied to
organic substances.^ It was thought that in the latter complex groups (radicals)
played the same role as that of the elements in inorganic chemistry. Organic
chemistry was defined as the chemistry of the compound radicals (Liebig, 1832),
and led to the chemical-radical theory, which flourished in Germany simultaneously
with the electro-chemical theory. According to this view, the object of organic
chemistry was the investigation and isolation of radicals, in the sense of the
dualistic idea, as the more intimate components of the organic compounds, and
by this means they sought to explain the constitution of the latter. (Liebig
and Wbhler, Ueber das Radical der Benzoesaure, A. 3, 249 ; Bunsen, Ueber die
Kakodylverbindungen, A. 31, 175 ; 37, i ; 42, 14 ; 46, i.)
In the meantime, about 1830, France contributed facts not in harmony with
the electro-chemical, dualistic theory. It had been found that the hydrogen in
organic compounds could be replaced (substituted) by chlorine and bromine,
without any important change in the character of the compounds. To the electro-
negative halogens was ascribed a chemical function similar to electro-positive
hydrogen. This showed the electro-chemical hypothesis to be erroneous.
The dualistic idea was superseded by a unitary theory. Laying aside all the
primitive speculations on the nature of chemical affinity, the chemical compounds
began to be looked upon as being constituted in accordance with definite funda-
mental forms — types — in which the individual elements could be replaced by
others (early type theory of Dumas, nucleus theory of Laurent) . Dumas, however,
distinguished between chemical types and mechanical types. He considered
substances to have the same chemical type, to be of the same species, when they
possessed the same fundamental properties, e.g. acetic and chloracetic acids.
Like Regnault, he considered that they were of the same mechanical type, belonged
to the same natural family, when they were related in structure but showed
a different chemical character, e.g. alcohol and acetic acid. At the same time, the
dualistic view on the pre-existence of radicals was refuted.
The correct establishment of the ideas of equivalent, atom, and molecule (Laurent
and Gerhardt) was an important consequence of the typical unitary idea of
chemical compounds. By means of it a correct foundation was laid for further
generalization. The molecule having been accepted as a chemical unit, the
study of the grouping of atoms in the molecule became possible, and chemical
constitution could again be more closely examined. The investigation of the
reactions of double decomposition, whereby single atomic groups (radicals or
residues) were preserved and could be exchanged (Gerhardt) ; the important
discoveries of the amines or substituted ammonias by Wurtz (1849), and Hofmann
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 19
(1849) ; the epoch-making researches of Williamson and Chancel (1850), upon
the composition of ethers ; and the discovery of acid-forming oxides by Gerhardt
(1851), — led to a " type " explanation of the individual classes of compounds.
Williamson referred the alcohols and ethers to the water type. A . W. Hofmann
deduced the substituted ammonias from ammonia. The " type " idea found
its culmination in the type theory of Gerhardt (1853), which was nothing more than
an amalgamation of the early type or substitution theory of Dumas and Laurent
with the radical theory of Berzelius and Liebig. The molecule was its basis, in
which a further grouping of atoms was assumed. The conception of radicals
became different ; they were no longer regarded as atomic groups that could
be isolated and compared with elements, but as molecular residues which remained
unaltered in certain reactions.
Comparing the carbon compounds with the simplest inorganic derivatives,
Gerhardt referred them to the following principal fundamental forms or
types ;—
C11 Hk> H)
H/ H/u H N
H\
H/
Hydrogen. Hydrogen Water. H
Chloride. Ammonia.
From these they could be obtained by substituting the compound radicals
for hydrogen atoms. All compounds that could be viewed as consisting of two
directly combined groups were referred to the hydrogen and hydrogen chloride
types, e.g. :
C,H5} C,Hd} CN} C.H.J C,H,0}
Ethyl Ethyl Cyanogen Ethyl Acetyl
Hydride. Chloride. Hydride. Cyanide. Chloride.
It was customary to refer all those bodies derivable from water by the replace-
ment of hydrogen, to the water type :
C,H,O}O> C,H.}O C,H.O}O
Alcohol. Acetic Acid. Ethyl Ether. Acetic Anhydride.
Associated types were included with the principal types. Thus, with the
fundamental type g| were arranged, as subordinates, the types ^£J * j; with
the water type ^ JO that of ** JS, etc.
All derivatives of ammonia were referred to the ammonia type :
CH,
H
H
CH8) C2H,0) c
N CH.N HN C°JN
CH8 H)
Methyl-amine. Trimethyl-amine. Acetamide. Cyanic Acid.
The types of Gerhardt were chemical types, as he himself expresses it : " Mes
types sont des types de double decomposition." It is thus understood that he
included the type with that of
These types no longer possessed their early restricted meaning. Sometimes
a compound was referred to different types, according to the transpositions
the formula was intended to express. Thus aldehyde was referred to the hydrogen
or water type ; cyanic acid to the water or ammonia type :
The development of the idea of polyatomic radicals, the knowledge that the
hydrogen of carbon radicals could be replaced by the groups OH and NH2, etc.,
contributed to the further establishment of multiple and minted types (Williamson,
Odling, Kekule) :
20 ORGANIC CHEMISTRY
Compound Types :
C1H\ H.
C1HJ H,
O.
-1
ir
C
O CO'
Ethylene Chloride. H) H2f
Ethylene Carbamide.
Glycol.
Mixed Types:
/H) HN
\Ht\Ot (Hi
j H,} |H}O
c.H.2} <W»}» C.H.O'}*
H2j°« HJO HJO
Chlorhydrin. Oxamic Acid. Amido-acetic Add.
The presentation of these multiple and mixed types depended on the poly atom*?
radicals of two or more type-molecules, il one may so name them, becoming united
into one whole — a molecule. Upon comparing these typical with the structural
formulae employed at present, we observe that the first constitute the transitional
state from the empirical, unitary formulae to those of the present day. The latter
aim to express the kind of grouping of the atoms in the molecule.
The next step was the expansion of the Gerhardt type to the —
H)
Marsh-gas type **|c by Kekult, 1856 (A. 101, 204).
Hj
Recent Views. — A year later Kekult (1857) in a communication, "Ueber
die sog. gepaarten Verbindungen und die Theorie der mehratomigen Radicale "
(A. 104, 129), indicated the idea of types by the assumption of a peculiar function
of the atoms — their atomicity or basicity (valence). This he supposed to be the
cause of the types of Gerhardt.
As early as 1852 Frankland had enunciated similar views in regard to the
elements of the nitrogen group (A. 85, 329 ; 101, 257 ; Frankland, Experimental
Reseaches in Pure, Applied, and Physical Chemistry, London, 1871, p. 147).
Kolbe concurred with these ideas (compare his derivation of the organic com-
pounds from the radical carbonyl C2 and carbon dioxide CaO4 — Kolbe' s Lehrbuch
der organischen Chemie, 1858, Bd. I. p. 567). The reason that they did not
exert greater influence upon the development of theoretical chemistry is mainly
due to the fact that the notions of the relations of equivalent weight and atomic
weight were not clearly defined by either of these two investigators.
In his assumptions Kekule rather returned to Dumas' mechanical types than
to the double decomposition types of Gerhardt. The distinction between the
type H| and jjf as drawn by Gerhardt did not exist for Kekule. The latter, in
1858, said, " It is necessary in explaining the properties of chemical compounds
to go back to the elements which compose these compounds." He continues :
" I do not regard it as the chief aim of our time to detect atomic groups which,
owing to certain properties, may be considered radicals and thus to include the
compounds under certain types, which in this way have scarcely any other signi-
ficance than that of type or example formula. I am rather of the opinion that
the generalization should be extended to the constitution of the radicals them-
selves, to the determination of the relation of the elements among themselves,
and thus to deduce from the nature of the elements both the nature of the radicals
and that of their compounds " (A. 106, 136).
The recognition of the quadrivalence of the carbon atoms and the power they
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 21
possessed of combining with each other, accounted for the existence and the
combining value of radicals ; also, for their constitution (Kekule, I.e., and Couper,
A. ch. phys. [3] 53, 469). The type theory, consequently, is not, as sometimes
declared, laid aside as erroneous ; it has only found generalization and ampli-
fication in a broader principle — the extension of the valence theory of Kekule
and Couper to the derivatives of carbon.
Whilst formerly it was the custom to consider in addition to entpiricaliormulx,
representing merely an atomic composition of the molecule, also rational formulae
(Berzelius), which in reality were nothing more than reaction formulae adopted
to explain to a certain degree the chemical behaviour of derivatives of carbon.
Kekuld now spoke of the manner of the union of the atoms in the molecule, by know-
ledge of which the constitution of the carbon compounds may be determined
(constitutional formula). Lothar Meyer next introduced the phrase "linking of
the carbon atoms." The expression structure (structural formula;) originated with
Butlerow.
An application of the valency theory, which has been remarkably fruitful, is
the Kekule benzene theory. Here for the first time there was assumed to be present
in a carbon compound a closed carbon-chain, a ring consisting of six carbon atoms.
The rather singular stability of the aromatic bodies is due to the presence of this
" benzene ring." Korner applied these views to pyridine and deduced the pyridine
ring ; and in recent years numerous other ring-systems have been suggested and
substantiated.
Theory of Chemical Structure of Carbon Compounds. Theory of
Atomic Linking, or the Structural Theory.
Constitutional or structural formulae are based upon the following
principles, which have been deduced from experiment and repeatedly
confirmed : —
1. The carbon atom is quadrivalent. The position of. carbon in the
periodic system gives expression to this fact. One carbon atom can
combine at the most with four similar or dissimilar univalent atoms or
atomic groups :
CH4 CF4 CC14
Methane. Carbon Tetrafluoride. Carbon Tetrachlorid«.
CH3C1 CH3NH2 CH,C12 CHC18
Methyl Chloride. Methylamine. Dichloromethane. Chloroform.
In a few compounds, such as carbon monoxide CO, the isonitriles or carbyl-
amines R'-N=C (A. 270, 267) ; and fulminic acid HO-N=C (A. 280, 303) carbon
behaves as a bivalent element.
2. The four units of affinity of carbon are equal, i.e. no differences
can be discovered in them when they form compounds. If one of the
four hydrogen atoms in the simplest hydrocarbon, CH4, be replaced
by a univalent atom or univalent atomic group, each mono-substitution
product will appear in but one modification. The four hydrogen
atoms are similarly combined, consequently it is immaterial which of
them is replaced.
CHSC1 CHjOH CH8NH,
Chlorome thane. Methyl Alcohol. Methylamine.
are known in but one modification each (p. 29).
3. The carbon atoms can unite with each other. When two carbon
atoms combine the union can occur in three ways :
(a) The two carbon atoms unite with a single valence each, leaving
the atomic group, 5=C — C==, with six free valences.
22 ORGANIC CHEMISTRY
(6) The two carbon atoms unite with two valences each, constitu-
ting an atomic group, =C=C=, with four free valences.
(c) Two carbon atoms are united by three valences,
group— C=C— has but two uncombined valences.
In the first case the union of the two carbon atoms is single, in the
second case double, and in the third case triple. Carbon atoms can
combine with themselves to a greater degree than the atoms of any
other elements. This gives rise to carbon nuclei, and carbon skeletons,
which form either open or closed chains or rings. The uncombined
valences of the carbon nuclei can saturate or take up atoms of other
elements or other atomic groups. This explains th« existence of the
innumerable carbon compounds.
This mutual union is indicated, according to the recommendation
of Couper, by lines. These formulae represent the internal construction
of the compounds, and are known as structural formula :
H OH
I !
H— C— C— H
H H
Ethyl Alcohol.
H H OH
I I I
C=0 H— C— C=O
I I
H H
Formaldehyde. Acetic Acid.
Such structural formulae have been deduced, by the help of the valency
theory, from reactions which result in the building up and the breaking down
of carbon compounds. They express clearly the relations between the bonds,
which, in the main, determine the behaviour of the substance. Those atoms
within the molecule which are bound most directly to each other exercise the
greatest influence on one another. But it must not be supposed that atoms,
unconnected directly by bonds, exert no mutual influence; such structural
formulas give no information of their relative distances apart in space. In the
study of reactions where halogen atoms are substituted for hydrogen in the
molecule, it is immediately apparent that such replacement takes place with
varying facility. This is specially obvious in the case of the aromatic substances
(see Volume II). Further, the carboxyl group reacts with different degrees of
acidity varying with the individual acid. Reactions, in which the loss of some
atoms causes a single bond to become a multiple one, or the formation of a ring
complex, and where intra-molecular atomic migration (see p. 36) takes place,
obviously depend on the mutual influence of atoms unconnected directly by
bonds, as shown in the structural formulae.
Kekulis valency theory explains clearly the function of the main bonds in
our structural formulae, but does not deal with the subsidiary action of the
various atoms on one another in the molecule. And yet one cannot go so far
as to say that in each atomic constellation which constitutes a molecule, every
atom exerts a chemical influence on every other. But so much can be asserted,
that each atom contained in the molecule of a chemical compound is bound to
each other atom in that molecule. To illustrate such attractions diagrammati-
cally, it would be necessary to draw a network of interatomic bonds in every
atomic formula. The greater or lesser strength of the bond could be indicated
by a thicker or finer line. If such a diagram were examined at a certain distance,
only the thick lines — Bonds of the First Order — would be seen clearly, i.e. practi-
cally the same in appearance as the structural formula ordinarily represented.
In many cases it can be deduced from the behaviour of the substance that
the Bonds of the Second Order exert an influence of negligible strength.
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 23
An external sign of the presence of such subsidiary valency — bonds of appreci-
able influence — is found in the absence of such chemical reactions as might be
expected to take place by analogy with others. Another exists in the relative
ease with which a group of atoms can be split off, which indicates the pre-
existence in the original molecule of such a group held together by these
second-order bonds.
Saturated and Tlnsaturated Compounds. — Saturated carbon com-
pounds are those in which only singly bound carbon atoms occur.
They cannot be united by more valences unless the carbon chain is
broken up. Unsaturated compounds are those in which doubly or
triply bound carbon atoms exist. As a single union is sufficient to
link carbon atoms together, a pair of carbon atoms with double union
can take up two additional valence units, if one of the double bonds
becomes broken, for this purpose, leaving the other to avoid destruc-
tion of the chain, e.g. :
H
I
H— C— H
II + 2H =
H— C— H H-
Ethylene.
II
Ethane.
Two carbon atoms, trebly linked, can tak« up four valences. The
dissolution of the triple union may proceed step by step, whereby it
may first be changed to a double linkage and then to a simple union :
H
C— H 2H H— C— H 2H H— C— H
C— H H— C— H H— C— H
The unsaturated compounds, by the breaking down of their double
and triple unions and the addition of two or four univalent atoms,
pass into saturated compounds.
This same behaviour is observed with many other compounds containing
carbon and oxygen, doubly combined, =C=O (aldehydes and ketones) or double
and triple union of carbon and nitrogen, =C=N— C=N (acid nitriles, imides,
oximes). They are in the same sense unsaturated ; by the breaking down of
their double or triple union they change to saturated compounds in which the
polyvalent atoms are linked by a single bond to each other :
H H
H-C=O C=N
H-C-OH | H-C-NH,
H— C— H + 2H - H— C— H + 4H - I
H-C-H I H-C-H
HI H !
H H
Acetaldehyde. Ethyl Alcohol. Acctonitrile. Ethylamine.
A second class of unsaturated carbon compounds exists, where the carbon
atom itself and alone must be looked on as being unsaturated. (A. 298, 202.) For
example :
=C=O =C=N.CaH5 -C=N.OH
Carb»n Ethyl Carbylamine Fu'minic Acid.
Mono-ide. and homologues.
24 ORGANIC CHEMISTRY
Eadicals, Eesidues, Groups. — The assumption of the existence
of radicals, capable of existing alone and playing a special rdle in mole-
cules, has long been abandoned (B. 35, 1196). The structural formulae
assign no especially favourable position to one atom over another in
the molecule. Radicals are atomic groups, chiefly those containing
carbon, which in many reactions remain unaltered and pass from one
compound into another without change. In this category must also
be included the uni-, di-, tri-, and polyvalent atomic complexes, which
remain when atoms or atomic groups are imagined to be removed from
saturated bodies. By such gradual abstraction of hydrogen, methane
yields the following radicals, having different valences : —
CH, — CH, j=CH, — CH
Methane, Methyl, Methylene, Methenyl or Methine,
saturated. univalent radical. divalent radical. trivalent radical.
If such radicals are isolated from existing compounds, e.g. the
halogen derivatives, then two of them unite to form a molecule :
CH,I CH3
-f- 2Na «= I + 2NaI
CH3I CH8
CH,I, CH,
CH,I, CHa
CHCl, CH
+ 6Na = HI + 6NaCl
CHCl, CH
Or, an atomic rearrangement may occur with the production of a
molecule of the same number of carbon atoms :
CHCl, CH, CH
+ 2Na= H
CH, CH,
+ 2Na = H +2NaClandnot |
CH,
The expressions residue and group are similar to radical. They
are chiefly applied to inorganic radicals, e.g. :
— OH water residue or Hydroxyl group,
— SH hydrogen sulphide residue or Hydrosulphide group,
— NH, ammonia residue or Amido group,
=NH Imido group,
— NO, Nitro group,
— NO Nitroso group.
Homologous and Isologous Series. — Schiel, in 1842 (A. 43, 107; 110, 141),
directed attention to the phenomenon of homology, giving as evidence the alcohol
radicals, and was followed shortly after by Dumas, who observed it in the fatty
acids. Gerhardt introduced the terms homologous and isologous series, and showed
the role these series played in the classification of the carbon derivatives. It
was the theory of atomic Unking that first disclosed the cause of homology.
The different kinds of linkages between the carbon atoms shows
itself most plainly among the hydrocarbons. By removing one atom
of hydrogen from the simplest hydrocarbon, methane, CH4, the remaining
univalent group, CH8, can combine with another, yielding CH3— CH3,
or C2H«, ethane or dimethyl. Here, again, a hydrogen atom may be
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 25
replaced by the group CH8, resulting in the compound CH3 — CH2— CH3,
propane. The structure of these derivatives may be more clearly
represented graphically :
H H
H— C— C— H
I I
H H
By continuing this chain-like union of the carbon atoms, there
arises an entire series of hydrocarbons :
CH8— CH,— CHa— CH, CH8— CH2— CH2— CHt— CH,, etc.
C4H10 C6Hia
Such a series of bodies of similar chemical structure and corre-
sponding in chemical characters is known as a homologous series.
The composition of such an homologous series can be expressed by
a general empirical or rational formula. The series formula for the
marsh gas or methane hydrocarbons is CMH2«+2»
Each member differs from the one immediately preceding and the
one following by CH2. The phenomenon of homology is therefore
due to the linking power of the quadrivalent carbon atoms.
On the configuration of the carbon chain, see C. 1900, II. 28, 664,
1256, and Volume II., Cycloparaffins.
In addition to the homologous series of the saturated marsh-gas
type, there are a large number of other such series, of which the simplest
are those of the monohydroxy-alcohols, the aldehydes and mono-
car boxy lie acids.
CnH2n+20 CMHanO CnH8nOt
CH4O Methyl Alcohol CH3O Formaldehyde CH2O2 Formic Acid
CSH6O Ethyl Alcohol C2H4O Acetaldehyde C2H4O2 Acetic Acid
C3H8O Propyl Alcohol C8H6O Propionaldehyde C,H6O2 Propionic Acid
C4H10O Butyl Alcohol C4H8O Butyraldehyde C4H8Oa Butyric Acid
etc. etc. etc.
Carbon compounds, chemically similar, but differing from each other in com-
position by a difference other than wCHs, e.g. the saturated and unsaturated
hydrocarbons, form isologous series, according to Gerhardt :
C2H8 ...... CaH4 ...... C2Ha
C8H8 ...... C8H8 ...... C8H4
Isomerism : Polymerism ; Metamerism ; Chain or Nucleus Iso-
merism ; Position or Place Isomerism. — The view once prevailed
that bodies of different properties must necessarily possess a different
composition. The first hydrocarbons showing that this opinion was
erroneous were discovered in 1820.
Liebig, in 1823, demonstrated that silver cyanate and fulminate were identical.
In 1828 Wohler changed ammonium cyanate to urea, and in 1830 Berzelius estab-
lished the similarity of tartar ic acid and racemic acid.
Berzelius, in 1830, designated as isomers (i<rofjL€prj<>, composed of
similar parts) bodies of similar composition but different in properties.
A year later he distinguished two kinds of isomerism, viz. : isomerism of
26 ORGANIC CHEMISTRY
bodies of different molecular ma.ss—j>olymerism ; and bodies of like
molecular mass — metamerism.
Numerous isomeric carbon derivatives were discovered in rapid
succession ; hence, an answer to the question as to what causes iso-
meric phenomena acquired importance for the development of organic
chemistry. The deeper insight into the structure of carbon compounds,
which was gradually attained, gave rise in consequence to a further
division of metameric phenomena.
The expression metamerism was employed to designate that kind of
isomerism which is due to the homology of radicals held in combina-
tion by atoms of higher valence. If the homologous radicals are
joined by polyvalent elements, then those compounds are metameric,
in which the sum of the elements contained in the radicals is the
same (H may be viewed as the simplest radical) :
/-» TT N QJJ \
Hl^ is metameric with CH*K
Ethyl Alcohol. Methyl" Ether.
C,H7]
}O is metameric with >O
H) CH,|
Propyl Alcohol. Ethyl-Methyl
Ether.
C2H6) CH.l
H N is metameric with CH 3 }N
HI HI
Ethylamine. Dimethylamine.
C3H:
CH
H N is metameric with CH, N and CH3}N
H H) CHS|
Propylamine. Ethyl Methyl- Trimethyl-
amine. amine.
The constitution of the radicals in this division was disregarded,
the type formulae were sufficiently explanatory. We have recognized
the power of the quadrivalent carbon atoms to unite in a chain-like
manner as the cause of homology, and to this cause may be attributed
other phenomena of isomerism, which are not properly included under
metamerism.
In deducing the formulae of the five simplest hydrocarbons of the
homologous series CnH2n+2, the formula for ethane, CH3.CH3, was
developed from that of methane, CH4, and that of propane CH3.CH2.CH3
from the formula of ethane C2H6. In the case of propane intermediate
and terminal carbon atoms are distinguished. The former are attached
on either side to two other carbon atoms, still possessing two valency
units which are saturated by two hydrogen atoms. The terminal
carbon atoms of the chain are linked to three hydrogen atoms.
With the next member of the series we observe a difference. Above
(p. 24), the fact that a hydrogen of the terminal methyl group of
propane was replaced by methyl was the only condition considered.
This led to the formula CH3.CH2.CH2.CH3. However, the CH3-group
might replace a hydrogen atom of the intermediate CH2-group, and
CH..CH.CH,
then the result would be the formula . In this hydro-
CH
carbon there is a branched carbon chain. The hydrocarbon with a
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 27
continuous chain is termed normal butane ; its isomer is isobutane,
i.e. isomeric butane.
Theoretically, by a similar deduction, the two butanes
CH,— CH,— CH,— CH, CH,CH(CH,),
Normal Butane. Isobutane.
yield three isomeric pentanes which are actually known.
CH,
CH,.CH8.CH2.CH2.CH, CH3.CH.CHa.CH, H,C— C— CH,
Normal Pentane.
CH, CH,
Isopentane. Pseudopentane
Tetramethyl Methane.
The number of possible isomers increases rapidly with the increase
in carbon atoms (B. 27, R. 725 ; 33, 2131).
The origin of isomerism in the homologous paraffins, as in so many
other cases, is the different constitution of the carbon chain. The
isomerism caused by a difference in linking, by the different structure
of the carbon nucleus or the carbon chain, is termed nucleus or chain
isomerism.
The investigation of the substitution products of the paraffin hydro-
carbons brings to light another kind of isomerism. The principle of
similarity of the four valences of a carbon atom (p. 21) renders logical
and possible but one monochloro-substitution product of methane and
ethane. The same consideration which heretofore recognized the
possibility of two methyl substitution products of propane (the two
butanes possible by theory) leads to the possibility of two monochloro-
propanes, dependent upon whether the chlorine atom has replaced the
hydrogen of a terminal or intermediate carbon atom :
CH,.CH,.CH,C1 CH,.CHC1.CH,
Normal Propyl Chloride. Isopropyl Chloride.
If two hydrogen atoms of one of the carbon atoms of propane
be replaced by an oxygen atom, the following case of isomerism
arises :
CH3.CHa.CHO CH,.CO.CH8
Propyl Aldehyde. Acetone.
In the case of the two known chloropropanes, and also in the case
of propyl aldehyde and acetone, the cause of the isomerism is not due
to difference in constitution of the carbon chain, but to the different
position of the chlorine atoms with reference to the oxygen atoms of
the same carbon chain. Isomerism, induced by the different arrange-
ment or position of the substituting elements in the same carbon chain,
is designated isomerism of place or position.
The intimate relationship of the two varieties of isomerism is appa-
rent from the derivation of the ideas of nucleus or chain isomerism and
place or position isomerism.
Recent Views on the Structural Jheory. — The theory of
atomic linking not only revealed an insight into the causes of the
innumerable isomeric phenomena, but predicted unknown instances
28 ORGANIC CHEMISTRY
and determined their number in a very definite manner. In many
cases isomeric modifications, possible by theory, were discovered at a
later period. For certain isomers, however, at first few in number,
the structural formulas deduced from their synthetic and analytical
reactions were insufficient, inasmuch as different compounds were
known, to which the same structural formula could be given. The
greatest similarity in reactions indicative of the structure was com-
bined with complete difference in physical properties of the com-
pounds belonging in this class. The tendency at first was to designate
such bodies physical isomers, meaning thereby an aggregation of
varying complexes of chemically similar molecules.
The following groups of such isomers have been well investigated :
HO.HC.CO2H
1. The four symmetrical dihydroxysuccinic acids : , the
HO.HC.COjH
ordinary or dextro-tartaric acid, and racemic acid, which were proved
to be isomeric in 1830 by Berzelius (see p. 25), and laevo-tartaric and
the inactive or meso-tartaric acids which were added later, through
Pasteur's classic researches.
CH.COjH
2. The two symmetrical ethylene-dicarboxylic acids : \\ , fu-
maric and maleic acid. CH.CO2H
3. The three a-hydroxypropionic acids: CH3.CH(OH).CO2H—
inactive lactic acid of fermentation, sarcolactic acid, and laevo-lactic
acid, which was added later.
Substances are included among these compounds, which when
liquefied, either by fusion or solution, rotate the plane of polarization
either to the right or left. The direction of deviation is indicated by
prefixing " dextro " or " laevo " to the name of the bodies thus acting.
Such carbon compounds are " optically active " (p. 54), in contra-
distinction to the other almost innumerable derivatives which exert no
influence on polarized light and are " optically inactive " or "inactive."
A direct synthesis of optically active carbon compounds has not
yet been achieved (see asymmetric synthesis, p. 55), although optically
inactive bodies have been synthesized. Pasteur discovered methods
by means of which the latter can be resolved into their components,
which rotate the plane of polarization to an equal degree but in
opposite directions. Upon splitting sodium-ammonium racemate into
sodium-ammonium laevo- and dextro-tartrates, Pasteur observed that
the crystals of these salts showed hemihedrism ; that they were as an
object to its mirror-image ; and that equally long columns of equally
concentrated solutions of these salts, at the same temperature, deviated
the plane of polarized light to an equal degree in opposite directions.
In 1860 Pasteur expressed himself as follows upon the cause of these phenomena
--upon molecular asymmetry : " Are the atoms of the dextro-acid grouped in the
>rm of a nght-handed spiral, or are they arranged at the angles of an irregular
trahedron or are they distributed according to some other asymmetric arrange-
We know not. Undoubtedly, however, we have to do with an asymmetric
arrangement, the images of which cannot mutually cover each other. It is not
less certain that the atoms of the laevo-acid are arranged in opposite order." In
>73y. Wtslicenus added the following comment to the evidence of similar
e m the optically inactive lactic acid of fermentation and the optically
<wtave sarcolactic acid : " Facts compel us to explain the difference of isomeric
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 29
molecules of like structural formula by a difference in arrangement of the atoms
in space." How the space configuration of the molecules of carbon compounds
was to be represented was answered almost simultaneously and independently of
each other by van 't Hoffand Le Bel (1874) (B. 26, R. 36), by the introduction
of the hypothesis of the asymmetric carbon atom. This hypothesis is the basis
of the chemistry of space or stereo-chemistry of the carbon atom.
The hypothesis of an asymmetric carbon atom * is designed to
explain optical activity and the isomerism of optically active carbon
compounds.
Whilst the theory of atomic linkage abstains from any representa-
tion of the spacial arrangement of the atoms in a molecule, experience
gathered from the investigation of simple carbon compounds shows
that definite spacial relations do not harmonize with actual facts.
Assuming that the four valences of a carbon atom act in a plane and
in perpendicular directions upon each other, the following possible
isomers for methane are evident : —
No isomers of the types CHgR1 and
Two „ „ „ CH2(Ri)2, CH2RiR», CHR*(Ri)2,
Three „
Methylene iodide, for example, should appear in two isomeric modifications
H H
I i
I— C— I and H— O— I
i i
However, two isomers of a single disubstitution product of
methane have never been found ; consequently, it is very improbable
that the four affinities of a carbon atom are disposed in the manner
indicated above. The carbon atom models of Kekulc represent the
carbon atom as a black sphere and the quadrivalence of it by four
needles of equal length and firmly attached to the sphere, which
Baeyer has called axes. These needles are not perpendicular to each
other, nor do they lie in the same plane, but are so arranged that
planes placed about their terminals produce a regular tetrahedron
(Z. f . Ch. (1867) N. F. 3, 216). Van 't Hoff's generalizations are based
upon this model, about which fundamental considerations will be more
fully developed in the following pages.
On the assumption that the affinities of a carbon atom are directed
towards the summits of a regular tetrahedron, in the centre of which is
the carbon atom, there would be no imaginable isomers coinciding
* Pasteur : Recherches sur la dissymetrie moleculaires des produits organiques
naturels. Lesons de chimie professees en 1860. Paris, 1861. Vgl. Ostwalti's
Klassiker der exacten Wissenschaften, Nr. 28 : Ueber die Asymmetr-ie bei
natiirlich vorkommenden organischen Verbindungen, von Pasteur. Uebersetzt
und herausgegeben von M. und A. Ladenburg. J. H. van 't Hoff : Dix annees
dans 1'histoire d'une theorie, 1887. K. Auwers : Die Entwickelung der Stereo-
chemie, Heidelberg, 1890. A. Hantzsch : Grundriss der Stereochemie, Breslau,
1893. C. A. Bischoff : Handbuch der Stereochemie, 1893, together with,
Materialien der Stereochemie, 1904. Werner: Lehrbuch der Stereochemie,
1904.
30 ORGANIC CHEMISTRY
withCH2(R1)2, CH2R1R2, CHR^R^but a case such asCHR^Ra or
the more general CR1R2R3R4 — an isomeric phenomenon of peculiar
nature — might be predicted. A carbon atom of this description — one
that is connected with four different univalent atoms or atomic groups
— van 't Hoff has designated an asymmetric carbon atom, proposing to
represent it by an italic C. It is often indicated by a small
star.
If a compound contains an asymmetric carbon atom we can
conceive of its existence in two isomeric modifications, the one being
an image of the other :
*
These spacial arrangements are more fully understood by the aid of the models
suggested by Kekutt, van 't Hoff, and others, than by their projection upon the flat
surface of paper. Van 't Hoff introduced tetrahedron models in which the solid
angles were coloured ; this was to represent and indicate different radicals. They
lack this advantage, possessed by the Kekult model, that the carbon atom has
entirely disappeared from the model. It must be imagined as being in the centre
of the tetrahedron, and in projections of these models (see above) the radicals are
united to each other by lines, the latter, however, not in any sense representing
a chemical union.
In the left tetrahedron the successive series RXR2R3 proceeds in a
direction directly opposite to that of the hand of a watch, whilst in
the right tetrahedron the course coincides with that of the hand. The
two figures cannot, by rotation, be by any means brought into the
same position, — that is, in a position to cover each other completely, —
any more than the left hand can be made to cover the right, or a
picture its image or reflection.
The Isomerism of Optically Active Carbon Compounds. — The
cause of optical activity, in the opinion of van 't Hoff and of Le
Bel, is the presence of one or several asymmetric carbon atoms in the
molecule of every optically active body. It is obvious that two mole-
cules which only differ in that the series of atoms or atomic groups
attached to an asymmetric carbon atom differ successively in order of
arrangement, which therefore are identical in chemical structure,
must be very similar in chemical properties. However, those physical
properties, upon which the opposite successive series of atoms or
atomic groups in union with asymmetric carbon exerts an influence,
e.g. the power of deviating the plane of polarized light, must be equal
in value, but opposite. The union of two molecules identical in
structure, having equal but opposite rotatory power, gives rise to a
molecule of an optically inactive polymeric compound.
Compounds containing an Asymmetric Carbon Atom. — tf-Hydroxy-
propionic acid, CH3— *CHOH.CO2H, is an example of a compound
containing one asymmetric carbon atom. It exists in two optically
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 31
active, structurally identical, but physically isomeric modifications, and
one optically inactive, structurally identical polymeric form :
Dextro-lactic Acid.
(Sarcolactic Acid.)
OH
C— H +
H,C C02H
OH
H— C
HOaC CH,
{(+) ^-Lactic Acid (
— ) /-Lactic Acid
Laevo-lactic Acid.
} °<
The following compounds also contain one asymmetric carbon
atom : —
Leucine ........ C4H,*CH(NH2)CO2H
Malic Acid ....... CO2H.CHa.*CH(OH)CO2H
Asparagine ....... CONH2CH2.*CH(NH2)CO2H
MandelicAcid ...... C6H5.*CHOH.CO2H
Each of the preceding bodies is known in two optically active and
one optically inactive modifications.
Compounds containing Two Asymmetric Carbon Atoms. — The relations
are more complicated when two asymmetric carbon atoms are present.
The simplest case would be that in which similar groups are in
union with the two asymmetric carbon atoms. The one half of the
molecule would then be constructed chemically exactly like the other
half. The four isomeric dihydroxysuccinic acids belong in this group.
This group of tartaric acids has become of the greatest importance in
the development of the chemistry of optically active carbon derivatives.
They were the first to be most carefully investigated chemically,
optically, and crystallographically, and were employed by Pasteur in
the development of methods for resolving the optically inactive com-
pounds into their optically active components (p. 56), Their im-
portance was further increased by the fact that they were brought
into an intimate genetic relation with fumaric and maleic acids — two
isomeric bodies which will be considered in the next section, (p. 34).
When a carbon compound contains two asymmetric carbon atoms,
united to similar groups, then a fourth compound becomes possible in
addition to the three isomeric modifications which a compound con-
taining only one asymmetric carbon atom is capable of forming. If
the groups linked to one asymmetric carbon atom, viewed from the
axis of union of the two asymmetric carbon atoms, show an opposite
successive arrangement to that of the other asymmetric carbon atom,
ORGANIC CHEMISTRY
an inactive compound results, due to an intramolecular or internal
compensation; the action due to the one asymmetric atom upon
polarized light will be cancelled by an equal but opposite action
caused by the other asymmetric carbon atom.
The hypothesis of the asymmetric carbon atom gave the first and,
indeed, the only satisfactory explanation for the occurrence of four
isomeric symmetrical dihydroxysuccinic acids, which are represented
as follows : —
—Off
HO
CO8H
H C— OH
CO,H
(i) Dextro-tartaric Acid. (2) Laevo-tartaric Acid. (3) Inactive or Meso-tartaric Acid.
Dextro-tartaric Acid + L»vo-tartaric Acid=(4) Racemic Acid.
It is seen that the two independent rotating systems are in contact
with one another at one angle of the tetrahedrons through a single
carbon bond.
An excellent example of the formation of a meso-form during the
purification of two optical antipodes, is supplied by laevo-alanyl-
dextro-alanine. It is itself optically active, but loses water, giving
rise to the meso-form of alanine anhydride (C. 1906, II. 59) :
CH,
/-Alanyl-r-alanine.
HOOC— C
H,C H
NH
I
C— CO
/\
H CH,
COC)C-
HN
I
C— C
H8C H
Meso-alanine Anhydride.
The possibilities of isomerism in carbon compounds containing
more than two asymmetric carbon atoms — a condition observable with
the polyhydric alcohols, their corresponding aldehyde alcohols, and
ketone alcohols (the simplest sugar varieties), as well as with their
oxidation products, will be more elaborately discussed under these
several groups of compounds.
Geometrical Isomerism, Stereoisomerism in the Ethylene Deriva-
tives (Alloisomerism),—Two carbon atoms, singly linked to eacl?
other, whose valences are not required for mutual union, and which are
united to other atoms or atomic groups, may be considered as being
able to rotate independently of each other about their axis of union
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 33
/. Wislicenus assumes, however, that the atoms or atomic groups
combined with these two carbon atoms exercise a "directing
influence" upon each other until finally the entire system has passed
into the "favourable configuration" or the "preferred position." It
follows from this assumption that, in ethane derivatives in which asym-
metric carbon atoms are not present, structurally identical isomers
cannot occur. When the van 't Hoff tetrahedron models are employed
for demonstration the two systems, capable of independent rotation
about a common axis, are found to touch one another through a single
carbon bond situated at one of the angles (comp. the projection-
formula of the tartaiic acids, p. 32).
A different state prevails where the carbon atoms are doubly linked.
The double union, according to van yt Hoff, prevents a free and inde-
pendent rotation of the two systems and space-isomers are possible.
The tetrahedron models represent this double union in such a
manner that two tetrahedra have two angles in common and are in
contact along a common edge. The frequent and notable differ-
ences in chemical behaviour of this class of isomers are to be attri-
buted to the greater or less spacial distance of the atomic groups,
which determine the chemical character.
Compounds having the general formulae abC=Cab or abC=Cac,
may exist in two isomeric modifications. In one instance groups of like
name are directed towards the same side — according to /. Wislicenus
the "plane symmetrical configuration" — or they are directed towards
opposite sides — then they have according to the same author the
central or axially symmetrical configuration. Baeyer suggests for this
form of asymmetry the term " relative asymmetry " in contradistinction
to the kind of asymmetry which substances with asymmetric carbon
atoms show ; the latter he prefers to call " absolute asymmetry"
The structurally symmetrical ethylene-dicarboxylic acid is the
most striking example of this class of isomerism. It exists in two
isomeric modifications, known as fumaric and maleic acids, both of
which have been very carefully investigated. Maleic acid readily
passes into an anhydride, hence the plane symmetrical configuration is
ascribed to it ; fumaric acid does not form an anhydride, so that the
axial symmetrical configuration is given to it, in which the two carboxyl
groups are as widely removed from each other as possible. In projec-
tion formulae and in structural formulae, to which there is given a
spacial meaning, the configuration of these two acids would be
represented in the following way : —
HC.C02H t * / \ H.C02H
CO^H
MaleTc Acid. Fumaric Acid.
Plane Symmetrical Configuration. Central or Axially Symmetrical Configuration.
VOL. I. D
HC.CO,H HO*C'<fH
o V v «=
34 ORGANIC CHEMISTRY
The isomertsm of mesaconic and citraconic acids, (CH3)(CO2H)
C=CH(CO2H), is of the same class ; the first acid corresponds to
fumaric acid and the second to maleic acid. Further examples of the
class are :
Crotonic and Isocrotonic Acids . . . £H8CH: CHCO2H
Angelic and Tiglic Acids .... CH..CH: : C(CHJCO2H.
Oleic and Elaidic Acids .... C,H17CH : CH.C7Hj4.CO,H.
Erucic and Brassidic Acids .... C8HlyCJi . (^ti.^^ti^^U^ti.
The two a-Chlorocrotonic Acids . . CH3.CH : CC1.CO2H,
jS-Chlorocrotonic Acids . . CH.,.CC1 : CH.COaH.
Tolane Dichlorides . . . C6HBCC1 : CC1C6H6.
Dibromides . . . C«H6CBr : CBrC,H6.
" o-Dinitrostilbenes .... NOa[2]CflH4[i]CH : CH[i]C§H4[2]NO,.
Cinnamic and Allocinnamic Acids . . C6H6.CH : CHCO2H.
The two a-Bromocinnauiic Acids . . CtH6.CH : CBrCOaH.
fl-Bromocinnamic Acids . . C,H6.CBr : CHCOaH.
," .I 5mm«icAcids HO[2]C.H4[i]CH:CH.COaH,etc.
Isomeric phenomena of this kind Michael designates as allo
isomerism, without suggestion as to its cause. When a body passes
into a more stable modification upon the application of heat, Michael
prefixes " allo " to the name of the more stable form ; thus, fumaric
acid is allomaleic acid (B. 19, 1384).
Fumaric and maleic acids are placed at the head of this class of
isomeric phenomena not only because they have been most thoroughly
investigated, but chiefly because the two optically inactive dihydroxy-
tartaric acids bear to them an intimate genetic relation (p. 31). Kekutt
and Anschtitz showed that fumaric acid was converted into racemic
acid, and maleic acid into mesotartaric acid by potassium permanganate.
This conversion harmonizes entirely with the van 't Hoff-Le Bel
conception of these four acids ; indeed, it might have been predicted.
These relations will be more fully elaborated in the discussion on the
acids. In studying maleic and the alkyl-malei'c acids, it will be further
discussed whether or not it is required by configuration that maleic
acid and its homologues should have a structure quite different from
that of fumaric acid. The relations are similar in the case of the cou-
maric acids (Vol. II.).
Baeyer considers that the isomerism of the saturated or carbocyclic compounds
bears a definite relation to the stereoisomerism of the ethylene derivatives, as will
be more fully explained when the hexahydroxyphthalic acids (Vol. II.) are
described. The same author maintains that the simple ring-union of carbon atoms
viewed from a stereochemical standpoint has the same signification as the double
union in open chains. Therefore, stereoisomerism in the carbon compounds
with double union would appear merely as a special case of isomerism in simple
ring-unions. Baumann applied this idea to saturated heterocyclic compounds —
to the polymeric thioaldehydes (q.v.).
Baeyer suggested the introduction of a common symbol for all geometrical
isomers, such as the Greek letter r. "The addition of an index will assist
the ready expression of the kind of isomerism. In the case of compounds which
contain absolute asymmetric carbon atoms, the signs -\ can be employed.
Thus the expressions
Dextro-tartaric Acid = r -j- -f )
Lsevo-tartaric Acid =r jTartaric Acid
Mesotartaric Acid = r H — |
can be understood without special explanation." In the case of relative asym-
metry in unsaturated compounds and saturated rings, Baeyer proposes to use the
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 35
terms cis and trans. Maleic acid = r*19- cl- or briefly F518 ethylene-dicarboxylic
acid, while fumaric acid = rcis- trans ethylene-dicarboxylic acid.
Further considerations on the space-configuration of the ethylene
and polymethylene derivatives lead to a broadening of the scope
and to the correction of the law, that an asymmetric carbon atom must
be present in every optically active compound (see above, p. 30).
Optical activity can occur even in the absence of an asymmetric carbon
atom in the ordinary sense, if the atoms are attached to a carbon skeleton
in such a way in space, that there is no plane of symmetry present — the
object and its mirror-image do not correspond. This is found, for
instance, in hexahydrohexahydroxybenzene, which exists in two enan-
tiomorphic optically active forms, as d- and /- inositol :
H
HO
rf- and /- Inositol.
Another example is found in d- and /- methyl-cyclohexylidene-acetic
acid,
CH, COOH HOOC CH.
2X \ /CH,— CHt. |
>c=c* *c=c< \c*
\—
Ht— CH/ x \ \:H,— CH/I
H H H
in which the CH3 and H, COOH and H, attached to the *C atoms must
lie in planes at right angles to each other as required by the condition of
asymmetry (Aschan, B. 35, 3389 ; Marckwold and Meth, B. 39, 1171).
The particularly ready formation of carbocyclic and heterocyclic
compounds when five or six carbon atoms take part in the ring forma-
tion, is also a result of the position of the atoms in space. This aspect
of stereochemistry will be considered in the introduction to the carbo-
cyclic compounds, and there also to the heterocyclic bodies, as well as
in the discussion of the cyclic carboxylic esters, or lactones, the cyclic
acid amides or lactams, the anhydrides of dibasic acids, etc.
Hypotheses Relating to Multiple Unions of Carbon. — The multiple
unions of carbon are so important in stereochemical considerations,
that there has been a large amount of research into the nature of this
union as well as attempts to represent it. All investigations in this
direction demonstrate how difficult it is at present to understand so
obscure a force as chemical attraction or affinity from a mechanical
point of view. Despite the demand and necessity that may exist for
the introduction of hypotheses dealing with the mechanics of multiple
linkage the views so far presented are in many essentials contradictory,
and not one has won general recognition for itself. See Baeyer (B. 18,
2277 ; 23, 1274) ; Wunderlich (Configuration organischer Molecule,
Leipzig, 1886) ; Lessen (B. 20, 3306) ; Wislicenus (B. 21, 581) ; V.
Teyer (B. 21, 265 Anm. ; 23, 581, 618) ; V. Meyer und Rieche (B. 21,
Mey
36 ORGANIC CHEMISTRY
946); Auwers (Entwicklung der Stereochemie, Heidelberg, 1890),
pp. 22-25 ; Naumann (B. 23, 477) ; Brilhl (A. 211, 162, 371) ; Deslisle
(A. 269, 97) ; Skraup (Wien. Monatsh. 12, 146) ; /. Thiele (A. 306, 87 ;
319, 129) ; Erlenmeyer, jun. (A. 316, 43 ; J. pr. Ch. [2] 62, 145) ;
Vorlaender (A. 320, 66) ; Hinrichsen (A. 336, 168).
Stereochemistry of Nitrogen. — Isomeric phenomena of nitrogen-containing
compounds of like chemical structure, which could not be ascribed to the same
cause as prevailed in carbon compounds, led to the application of stereochemical
views to the nitrogen atom. There appeared to be an absolute nitrogen asymmetry
corresponding to the absolute carbon asymmetry, of which examples were cited by
Le Bel in the unstable, optically active modification of methyl ethyl propyl
isobutyl ammonium chloride (C. r. 112, 724 ; B. 32, 560. 722, 988, 1409, 3508 ;
33, 1003 ; C. 1900, II. 77 ; C. 1900, I. 26, 179 ; 1901, II. 206, 409, etc.).
The relative asymmetry, due to the doubly-bound carbon atom, is seen in the
isomerism of the oximes (Hantzsch and Werner; comp. also W attach, A. 332,
337), of the hydroxamic acids (Werner), and of the aromatic diazotates, diazo-
sulphonic acids and diazocyanidcs (Hantzsch).
Stereochemistry of Tin: C. 1900, II. 34. Stereochemistry of Sulphur: C. 1900,
1.537; 11.623.
Intramolecular Atomic Rearrangements. — Many investigations
have shown that certain modes of linking, apparently possible
from a valence standpoint, cannot, in fact, occur, or when they do
take place are possible only under certain definite conditions. In
reactions, for example, in which two or three hydroxyl groups should
unite with the same carbon atom, a loss of water almost invariably
occurs and oxygen becomes doubly united with carbon, e.g. :
H.O ^O
CH3c-0— Hi --- > CH3C<^
/°~H\
f-0— Hi
\H /
/ /°-H\ -H,(
|HC(-O— HI --
\ X)— H/
On the other hand, the ethers derivable from these unstable
" alcohols " are stable :
/O.CaH6 XXC2H5
CH8C^-O.CaH6 and H(X— O.CaH8
\H XO.C2H6
In other cases there is a cleavage of a halogen hydride, water or
ammonia, with the production of an unsaturated body, or an anhydride
of a dibasic acid, or a cyclic ester (lactone), or a cyclic amide (lactam).
In these reactions two molecules result from one molecule, in which
atom-groups occur in unstable linkage-relations, an organic molecule
and a simple inorganic body.
This type of decomposition of a labile molecule is similar to the
phenomenon of intramolecular atomic rearrangement, where unstable
atomic groupings pass at the moment of their formation into stable
forms without the alteration of the size of the molecule. The hydrogen
atom, especially, is inclined to wander, but groups, such as the alkyl,
phenyl, and hydroxyl behave similarly. To-day, the number of
examples of this phenomenon is remarkably large, of which a few
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 37
only need be cited. A free hydroxyl group becomes added in most
cases to a carbon atom in double union with its neighbouring carbon
atom. When intramolecular atomic rearrangements occur the hydro-
gen of the hydroxyl attaches itself to the adjacent carbon atom, and
oxygen of hydroxyl unites doubly with carbon (Erlenmeyer's rule
B. 13, 309 ; 25, 1781).
(CH.OH\ CHO
CH2 / ' CH,
CHBr /CH.OH\ CHO
CH.
Vinyl Alcohol. Aldehyde.
CH, /CH, \ CH, !
CBr - -> f C.OH | — >- C=0
CH, \CH2 / CH,
/3-Allyl Alcohol. Acetone.
However, the ethers obtained from vinyl alcohol (q.v.) are stable :
CH2=CHO.C2H5 and CH2=C(O.C2H6)— CH3 are known.
It has also been observed that a transposition such as that described
above can occur by two unstable and similar molecules rearranging
with each other, so that two similar stable molecules result :
CH,=CH.OH CH,.CHO
HO.CH=CH, OCH.CH,
A rise of temperature is frequently necessary to induce many of
these reactions to take place. Both compounds are capable of
existence. Unsaturated acids pass into lactones. The intramolecular
atomic rearrangement proceeds in a direction favouring the formation
of a stable ring :
(CH,)aC ^ (CH,),C— — O
CH— CH,.CO,H ~ CH,— CH,CO
Isocaprolactone.
In other unsaturated compounds we observe that the unsymmetrical
is transformed into a symmetrical body through the rearrangement
of the double linking of carbon :
KCN
CH, : CH.CHaI -> CH, : CH.CH2.CN -> CH,.CH : CH.CN ->
Allyl Iodide. Nitrile of Crotonic Acid.
CH8.CH : CH.CO,H
Crotonic Acid.
CH,=C— CO CH,.C CO
>0 ->
I >
CH— CO
CH..CO
Itaconic Anhydride. Citraconic Anhydride.
The esters of hydrothiocyanic acid, under the influence of heat,
rearrange themselves into the isomeric mustard oils, sulphur unites
doubly with carbon and the alcohol radical that had previously been
in union with the sulphur wanders to nitrogen :
C3H6— S— C=N > S="C=N.C3H,
Allyl Tbiocyanate. Allyl Mustard Oil.
ORGANIC CHEMISTRY
Isonitriles or carbylamines, when heated, pass into nitriles ; the
alcohol radical previously in union with nitrogen, wanders to carbon :
C,H6— N=C-
Phenyl Carbylamine.
(Vol. II.)
CaH6— CE=N.
Benzonitrile.
(Vol. II.)
Other rearrangements among the atoms of compounds only take
place in the presence of a strong acid or base. Indifferent bodies pass
over into basic or acid compounds :
NH.C6H6 HCI
NH.C6H5
Hydrazo benzene (indifferent).
CO.C6H6 KOH
CO.C6H5
Benzil (inditferent).
C.H^.NH,
CqH4.NH2
Benzidine (diacid base).
CeH,
\:(OH)COtH
C8H6
Eenzilic Acid (strong acid).
Further examples of intramolecular rearrangements of aromatic
bodies are diazobenzoic acid, phenylhydroxylamine, diazoamido-com-
pounds, etc. (see Vol. II.).
Pseudo-forms, Pseudomerism, Desmotropy, Merotropy, Tauto-
merism, Phasotropisin. — The study of these intramolecular atomic
migrations led to the recognition of a large number of atomic groups
as being labile and stable. In the case of many bodies it became
known that apparently they could react in accordance with two different
formula. In other words, as our constitutional formulae were deduced
from chemical behaviour, it may be said that compounds existed to
which two, and under certain circumstances more, constitutional
formulae could be ascribed. Baeyer (B. 16, 2188) explained this pheno-
menon in such a manner that the stable bodies, under the influence of
heat or reagents, passed into unstable modifications. " These isomers
are only known in compounds ; in the free state they revert to the
original form. Their instability is referable to the mobility of the
hydrogen atoms, since the replacement of the latter is followed by
stability " (compare A. W. Hofmann, B. 19, 2084). Mention may be
here made of :
SH
or
NH
S
cf cf
\S-R ^S
Hydrothiocyanic
Acid.
Isothio-
cyanic Acid.
Vxv Ul
\NH2
r ^
X^NH
Cyanamide.
Carbodi-imide.
— CH
— CH2
II or
1 e-t
— C.OH
—CO
Hydroxyl
Ketone
orEnol
Form.
Form (J. pr.
Ch. [a] 50, iaj).
Known.
cf
\NR,
Known.
Known (mustard
oils).
Known.
CHCO,C,H6 CH2.CO2
II or |
C.(OH).CH, CO.CH,
Acetoacetic Ester.
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 39
— N — NH ^-"N ^-NH
II or e.g. C6H4\ || or C6H4\ |
— COH —CO XXDC.OH XCOCO
Lactime Lactam -__ — ^ — • -
Form. Form. Isatine.
Baeyer proposes to represent the unstable modifications by the
designation " pseudo." Pseudomerism is the term that will be adopted
in this work for the phenomenon in which one and the same carbon
compound can react in accordance with different structural formulae.
The unstable form of a derivative will, therefore, take the name
" pseudoform " or " pseudo-modification." In some instances both
forms are known.
Closely related to the conception of pseudomerism is that of Desmotropy,
derived from Seo-^Js, a bond, and rptirciv, to change (P. Jacobson, B. 20, 1732,
footnote ; 21, 2628, footnote ; L. Knorr, A. 303, 133 ; Hantzsch, B. 20, 2802 ;
21, 1754 ; Forster, B. 21, 1857). Michael suggested the name " Merotropy "
(B. 27, 2128, footnote ; J. pr. Ch. [2] 45, 581, footnote ; 46, 208).
It is noteworthy that most pseudomeric compounds are acid in character;
they can form salts. When these salts are treated with alkylogens or acylhalides
the two classes of isomers appear. H. Goldschmidt (B. 23, 253) refers this
phenomenon to the appearance of free ions. Hence in passing judgment upon
questions of pseudomerism only those reactions can be considered, from which
electrolytic dissociation is excluded. Michael (J. pr. Ch. 37, 473) puts forward the
noteworthy suggestion that in the transpositions of the salts by organic halides
two independent processes, depending on the conditions present, take place : that
there is a simple exchange whereby the organic radical takes the place of the
metal ; or the radical halide first adds itself to the molecule and subsequently
separates as a metallic halide. In the latter case the organic radical assumes a
position different from that previously held by the metallic atom (compare
acetoacetic ester and malonic ester) . Nef has recently maintained the correctness
of Michael's view.
Laar, on the contrary, following Butlerow (A. 189, 77), van 't Hoff (Ansichten
iiber die organische Chemie, 2, 263) and Zincke (B. 17, 3030), assumes that such
compounds consist of a mixture of structural isomers, in that an easily mobile
hydrogen atom oscillates between two positions in equilibria, and thereby the
entire complex becomes mobile. He designates the phenomenon as tautomerism.
Discarding the uncertainty introduced into the classification of the carbon com-
pounds by the acceptance of this view, it has been noted that carbon compounds
which Laar considers mixtures of structurally isomeric bodies do not differ in their
physical properties from carbon compounds which offer no place in their structure
for this equivocal assumption. By the assumption of tautomerism with the
underlying meaning assigned it by Laar, the experimental solution of the problem
as to the conditions under which pseudo-forms are capable of existence is without
object. Although from the nature of the case the identification of easily alterable
intermediate reaction-products must continue to be one of the most difficult
problems, yet success has been met with in quite a number of cases. At a time
when chemical investigations at very low temperatures can so easily be carried
on by means of readily obtainable liquid air, experiments on the conditions of
existence of labile modifications will be started afresh.
The preceding section was prepared in 1893. Since then, numerous confirma-
tions of these views have been found. The ketones constitute the most important
class of compounds, which are tautomeric. In them, as in acetoacetic ester, the
oscillation is between the paraffin ketone and the olefine hydroxyl or enol
formula (p. 40).
The investigations of Claisen (A. 291, 25 ; 297, i), Guihzeit (A. 285,
35), W. Wislicenus (A. 291, 147), Knorr (A. 293, 70 ; 303, 133 ; 306,
332), P. Raabe (B. 32, 84), Dimroth (A. 335, i), and others have demon-
strated that there exist compounds of the form— C(OH) =C — CO — ,
40 ORGANIC CHEMISTRY
which readily pass into the form— CO— CH— CO— , and conversely
are easily produced from the latter : " The character of the added
residue, the temperature and the nature of the solvent, in the case of
dissolved substances, determine which of the two forms will be the
more stable." Claisen designates the acidic enol-form the a-compound
and the neutral kefa-form the /3-body, e.g.
COC6H6
I
o-Tribenzoyl Methane CiH6C(OH)=C— COCflH6
COCflH5
j8-Tribenzoyl Methane C,H,CO— CH— COC6H6.
The system of nomenclature proposed byHanizsch for pseudomeric
substances (B. 38, 1000) appears to be most suited for its purpose. If
the accustomed name refers to a " pseudo-acid " (the weaker acid or
neutral form), then the name of the real acid is characterized by the
prefix " aci " ; for instance, CH3CO— CH2— COOC2H5 is called aceto-
acetic ester, and CH3C(OH) =CH— COOC2H5 is named ««-acetoacetic
ester.
If the usual name denotes the strong acid, then that of the
pseudo-acid is prefixed by the word " pseudo," as, for example,
CH2.C(OH) =CH-CO.6 is called tetronic acid, and CH2.CO*-CH2-C0.6
is pseudo-tetronic acid.
Claisen was the first to show that, in the above example of the two
tribenzoyl methanes, only compounds having the a- or aci- constitution
form salts direct ; the (3- or pseudo-form yields no salts of the type
CO— CMe—CO, but gradually changes when in contact with bases,
into the salt of the aci-form CO — C=C(OMe) (see p. 41 ; slow or time
isomerisation phenomena).
The change of phenyloxybiazole carboxylic acid ester from one
pseudomeric form into the other has been quantitatively determined
by Dimroth by titration with potassium iodo-iodate. He found that
only the aci-form precipitated iodine while forming a salt, and that
the pseudo-form remained unaltered.
Substances such as acetoacetic ester, malonic ester and others
possessing the grouping — CO — CH2 — CO — are considered to exist in
the pseudo-form, since only one form has been isolated, and this yielded
no salts of its own ; those which have been obtained, are metallic
hydroxyl-substitution compounds of the aci-form.
The phenomenon of pseudomerism in these compounds can be
further complicated by the intervention of stercoisomerism (p. 32) in
enol-forms (see Diacetosuccinic acid ester, Knorr, A. 306, 332 ; Formyl
phenyl acetic ester, Z. phys. Ch. 34, 46, etc. ; on the other hand,
see Michael, B. 39, 203).
Physical methods have proved exceedingly helpful in determining
the constitution of the pseudomers, and in following the mutual
interchange of forms. Molecular refractions in particular have been
determined, as, for instance, in the case of acetoacetic ester and its
salts (Briihl, J. pr. Ch. [2] 50, 119 ; B. 38, 1868 ; Hatter and Mullet,
CHEMICAL CONSTITUTION OF CARBON COMPOUNDS 41
C. 1905, 1. 349, etcO > as wel1 as dielectrical constants (Drude, Z. phys.
Ch. 23, 308), and the magnetic rotation (Per kin, Sen.).
The investigations of Holleman (B. 33, 2912) and of Hantzsch have
enabled the presence of pseudomerism to be detected by electric con-
ductivity measurements. This is only possible when one of the two
possible forms is a weaker electrolyte than the other, as, for example,
in the case of certain nitro-fatty bodies -R.CH2NO2, R.CH(NO2)2.
Such compounds are gradually changed by alkalies into isonitro-
bodies, RCH=NOOMe, etc. ; and from these salts the addition of the
equivalent quantity of hydrochloric acid liberates the isonitro-body
itself. In solution these iso-compounds revert to the true nitro-
body with a greater or less velocity which can be followed by the
diminution in electric conductivity, and the gradual disappearance
of the red colour given with ferric chloride, which is a general cha
racteristic for the aci-form of a compound (slow or time isomerization
phenomena, B. 39, 2089, 3149, 2265).
Chromopseudomerism or Halochromism is the name given to the
phenomenon of a colourless or feebly coloured substance yielding a
strongly coloured salt with colourless bases or acids. Such an occur-
rence was referred by Hantzsch (B. 39, 3080) to pseudomerism, where a
colourless pseudo-electrolytic radical yielded a coloured ion. Examples
of this are found in the coloured salts of nitroform, vhluric acid, etc.
Halochromism is specially developed in the ortho-and para-deriva-
tives of the benzene series (see Vol. II.), which behave, on the one hand,
like the mostly colourless true benzene compounds, and on the other
like the mainly strongly coloured derivatives of quinone ; this class
of bodies includes o- and p- nitroso- and nitrophenols, o- and p- amino-
and oxyazo- bodies, derivatives of triphenyl carbinol, etc., classes of
bodies to which the coal tar dyes belong, to which the study of pseudo-
merism is of special importance. V. Baeyer and others (B. 38, 570 ;
39, 2977) consider halochromism can also occur in certain cases without
any real alteration in structure occurring. This is brought about by
one of the ordinary carbon valences changing into a so-called carbonium
valence, which Baeyer represents by a wavy line ; as for example :
(C6H6),C-OH (C6H,)8C O.SO.H.
Triphenyl Carbinol, Triphenyl Carbinyl Sulphate,
colourless. coloured.
In all the cases which have been considered, the interchangeable
isomers have belonged to two different classes of compounds with quite
different chemical characteristics. There exist, however, substances
which according to their mode of preparation should give rise to two
forms belonging to the same class, but which have turned out to be
identical with one another, as, for example, diazoamido-compounds,
amidines, formazyl derivatives of the general type —
^NX /NHX
R{ and R<
\NHY ^NY
where R represents N in diazoamido bodies, CH in the amidines, and
N : CH.N in the formazyl derivatives. This explains the absence of
certain isomerism phenomena in pyrrole, and such azoles as pyrazole
42 ORGANIC CHEMISTRY
and triazole (see Vol. II.), and also in the ortho-di-derivatives of ben-
zene (Vol. II., the Constitution of Benzene), etc. Attempts have been
made to explain these phenomena by assuming oscillations of Kekule's
valences (Knorr, A. 279, 188) ; and this is further complicated, in
the case of pyrrole and the azoles, by the wandering of a H atom. For
the phenomenon itslef Bruhl suggests the name Phasotropism (B. 27,
2396), whilst V. Pechmann puts forward the term virtual tautomerism
(B. 28, 2362).
THE NOMENCLATURE OF THE CARBON COMPOUNDS
The steadily increasing number of carbon derivatives has shown the absolute
necessity that definite principles should determine their designation. The absence
of such general and international rules (where they were possible) has led to great
confusion in the nomenclature.
Compounds originating from plants and animals received names that indicated
their origin, and often at the same time their characteristic chemical properties :
urea, uric acid, tartar, tartaric acid, formic, oxalic, malic, citric, salicylic acids,
etc. With a large class of bodies, e.g. the bases, glucosides, bitter principles,
fats, etc., it w'as customary to employ the ending " ine " : coniine, nicotine,
guanidine, creatine, betaine, salicine, amygdaline, glycerine, stearine, etc., and
in the terminations al, ol, an, en, yl, ylene, ylidene, the effort was made to show
the similarity of certain compounds, without, however, proceeding in a connected
way.
The more thoroughly the constitution of bodies became known, the greater
was the desire to indicate by names the manner in which the atoms were united.
This was especially true in the case of isomeric compounds. The manner in which
this was done, however, was left to the choice of the individual, and thus it
happened that often one and the same derivative received different names, which
possessed fundamentally equivalent meanings.
Of the early suggestions on nomenclature, that of Kolbe (A. 113, 307) on
carbinol deserves special consideration. As is known, Kolbe referred the names of
the monohydroxy saturated alcohols back to the name carbinol. In order to
make this principle more general, it becomes necessary to ascertain the carbinol
or carbinols for each class of compounds — that is, to find those bodies from
which the homologues might be derived, just as the monohydroxy saturated
alcohols might be deduced from methyl alcohol or carbinol. Without attempting
at this time to determine the limits of the " carbinol nomenclature," it will suffice
to remark that in the case of the paraffin dicarboxylic acids all the normal homo-
logues are the carbinols ; e.g. malonic acid, succinic acid, normal glutaric acid,
adipic acid, etc. Indeed, names such as monomethyl malonic acid, ethyl methyl
malonic acid, symmetric and unsymmetric dimethyl succinic acid, etc., are so
readily understood that they are preferred by many chemists.
In order to minimize as far as possible the arbitrary nomenclature of organic
compounds, a meeting was convened in Geneva, in 1892, of the chemists of nearly
all the civilized countries, for the purpose of agreeing on a method of indicating
the constitution of carbon compounds in a consistent and clear manner. The new
" official " names adopted by the Geneva Convention will, in the case of certain
important series of compounds, be observed in the present text ; they will be
enclosed in brackets— e.g. [ethene] for ethylene, [ethine] for acetylene, etc. The
designations of the simpler bodies — the names justified from an historical stand-
point and deduced from important reactions — will not be wholly eliminated.
Thus, the names ethyl hydride, dimethyl or methyl methane will be used for
ethane, depending upon what relations are especially to be emphasized.
The new nomenclature proceeds from, or begins with, the hydrocarbons. The
name of the hydrocarbon serves as the root for the names of those substances
which contain their carbon atoms arranged in a similar manner. The different
classes of bodies are distinguished by the addition of suffixes to the names of the
hydrocarbons : alcohols end in ol, aldehydes in al, ketones in one, and the acids
in acid— e.g. [ethanol]= ethyl alcohol, [ethanal] =acetaldehyde, [propanone]
=acetone, [propanal] =propionic aldehyde, [ethane-acid] = acetic acid. These
examples will suffice. The more detailed consideration will be given to the various
PHYSICAL PROPERTIES OF THE CARBON COMPOUNDS 43
classes of bodies, which are discussed. The principles of this nomenclature
have already been found difficult of application, especially in attempting
to indicate in name a compound having a mixed character — e.g. the body
COH — CH2 — CHOH — CO— COaH, which would be pentanolalone-acid. The
accumulation of suffixes, each of which possesses a meaning peculiar to itself,
has " conduit rapidement a des termes bizarres, d'une complication facheuse
et d'une prononciation difficile " (Am'e Pictet).
For the decisions of the International Congress of Geneva, convened igth to
22nd April, 1892, for the purpose of co-ordinating chemical nomenclature, see
Tiemann (B. 26, 1595) : Istrate's proposals (C. 1.898, I. 17). On the nomen-
clature of ring-compounds, see Vol. II.; also M. M. Richter (B. 29, 586).
In order to distinguish the more frequently occurring radicals of the same kind,
such as the univalent hydrocarbon residues, both aliphatic and aromatic, the name
alkyl has been accepted. In differentiating between the two classes alphyl refers
to the aliphatic residues and aryl to the aromatic ; whilst aromatic residues
possessing aliphatic characteristics are referred to as alpharyle. Carboxylic acid
residues, too, are referred to as acyl and differentiated into alphacyl and aracyl
(C. 1899, I. 825).
PHYSICAL PROPERTIES OF THE CARBON COMPOUNDS
It can, in general, be foreseen that the physical as well as the
chemical properties of carbon compounds must be dependent on their
composition and constitution. Such a regular connection has, how-
ever, only been determined for a few properties, of which the following
serve chiefly for external characterization : —
1. Crystalline form.
2. Specific gravity, density.
3. Melting point.
4. Boiling point.
5. Solubility.
For the investigation of constitution the following properties are
of importance : —
6. Optical properties.
(a) Refraction.
(b) Dielectric constants.*
(c) Optical rotation.
(d) Magnetic rotation.
7. Electrical conductivity.
I. CRYSTALLINE FORM OF CARBON COMPOUNDS
The crystalline form of a carbon derivative is one of its most im-
portant distinctions, whereby a body may be recognized most definitely
and differentiated from other substances ; so that the preparation of
organic substances in the form of crystals and their examination has
been of the greatest value in organic chemistry. The more com-
plex the constitution of a substance, the less the symmetry of its
crystals (B. 27, R. 843). The crystalline forms of isomeric bodies are
always different. Many substances may assume two or more forms ;
they are dimorphous, polymorphous, but each is characterized very
definitely by particular conditions of formation and existence.
* This is, strictly, an electrical constant, but owing to its close connection
with optical refraction, it is convenient to include it here, as in the German
ition. (Translator's note.}
44 ORGANIC CHEMISTRY
When it is possible for a compound to crystallize from the same solvent in
different forms, only one can separate within definite ranges of temperature.
The limit between these zones, the temperature of transformation, is theoretically
expressed by the point of intersection of the solubility curves of the
two crystalline forms. It is only the one or the other form that can appear
under normal conditions above or below this temperature. From a super-
saturated solution, and indeed a supersaturated solution of the two forms,
it is possible by the introduction of one or the other form, to obtain each
of the two kinds of crystals, and, indeed, both together, but only so long as the
supersaturation continues. After that, one of the two forms will gradually
dissolve and that one will remain which is the more stable at the temperature
of experiment. The temperature of transformation varies for each solvent, and
when impurities are present in the substances a greater or less variation in the
temperature will occur, according to the degree of impurity.
The existence and stability of a definite modification of a polymorphic sub-
stance depends to a great extent on the temperature, of which the influence, how-
ever, is not always the same. In the case of perchlorethane C2Cla, rhombic, tri-
clinic, and regular crystal forms are successively assumed during a gradual rise in
temperature, whilst on cooling, the same series is passed through in reversed order.
The change is said, therefore, to be reversible, and polymorphic substances of
this kind are called enantiotropic (Lehmann). With other bodies, however,
one modification may be labile and the other stable, so thav the first form
changes into the second, and not vice versfi. As an example, paranitrophenol
C6H4.OH.NO2 (1,4) may be taken. On solidification from the molten state, or
from a hot solution, it crystallizes in the colourless labile form. This, on standing,
turns into the stable yellowish-red modification, which is quite different in its cleav-
age and optical properties from the first. It can also be obtained by crystallizing
from a cold solution. Such substances, which undergo a change in one direction
only, are called monotropic. In many cases, however, a rigid grouping of the
numerous polymorphic organic bodies in one or other of the two groups is not
always easy. For the assumptions necessary for the explanation of the pheno-
menon, see Zincke (A. 182, 244) and Lehmann (Molecular physik, Leipzig, 1888/89) ;
Graham-Otto (Lehrbuch der Chemie, Vol. I., Part 3, p. 22, 1898).
At the present time little is known about the inner connection between the
crystalline form and chemical constitution of carbon compounds, but it has
been found, for example, that the slightest variation in chemical constitution
does affect the amount of rotation exhibited by optically active compounds. Many
such substances possess a hemihedral form, and the two optically active modi-
fications of a carbon compound, although they exhibit the same geometrical
constants, are distinguished by peculiar left and right types (enantiomorphous
forms) ; they are not superposable. The difference between two such com-
pounds, in which the atoms are similarly united, is only due, according to the
hypothesis of an asymmetric carbon atom (p. 30), to the difference in arrangement
of the atoms within the molecule. From this it follows that this variation in
arrangement finds expression in the crystalline form (comp. B. 29, 1692).
Laurent, Nicklts, de la Provostave, Pasteur, Hjortdahl (see F. N. Hdw. 3, 855)
investigated the influence that chemical relations of organic bodies exerted upon
the geometrical properties of their crystals. This problem, however, first
appeared in the forefront of crystallographic study after P. Groth introduced
the idea of morphotropy (Pogg. A. 141, 31). By this term was understood the
phenomenon of regular alteration of crystalline form produced by the entrance
of a new atom or atomic group for hydrogen. Groth, Hintze, Bodewig, Arzruni,
and others frequently called attention to such morphotropic relations particularly
with the aromatic bodies (comp. Physikal. Chemie der Krystalle von Andreas
Arzruni, 1893).
The recognition of the connection between crystalline form and chemical
constitution is rendered more difficult by the fact that as yet an accurate
in the salts of organic acids, consult Z. phys. Ch. 19, 441.
SPECIFIC GRAVITY OR DENSITY 45
2. SPECIFIC GRAVITY OR DENSITY
By this term is understood the relation of the absolute weight of
a substance to the weight of an equal volume of a standard body.
Conventional units of comparison are water for solids and liquids,
and air or hydrogen for gaseous bodies (see p. n). The number repre-
senting the specific gravity of a compound is as great as that repre-
senting its density. It frequently occurs, therefore, that the terms
specific gravity and density are used interchangeably.
Density of Gaseous Bodies. — For these, as we have already seen, the
relation of the specific gravity (gas density) to the chemical composi-
tion is very simple. Since, according to Avogadro's law, an equal
number of molecules are present in equal volumes, the gas densities
stand in the same ratio as the molecular weights. Being referred to
hydrogen as unit, the gas densities are one-half the molecular weights.
Therefore, the molecular volume, i.e. the quotient of the molecular
weight and specific gravity, is a constant quantity for all gases (at
like pressure and temperature).
Density of Liquid and Solid Carbon Derivatives. — In the liquid and
solid states the molecules are considerably nearer each other than
when in the gaseous condition. The size of the molecules and their
distance from each other, which increases in different degrees with
rise of temperature, are unknown, so that the theoretical bases for
deducing the specific gravity are lacking. However, some regularities
have been established empirically, which, by comparison with the
specific or molecular volumes, give the ratio of molecular weight to
specific gravity.
The relations between the specific volumes of carbon compounds were first
systematically studied by H. Kppp, in 1842 (A. 64, 212 ; 92, i ; 94, 257 ; 96, 153,
etc., to 250, i). He felt justified from his observations in proposing : " That
the specific volume of a liquid compound (molecular volume) at its boiling point
is equal to the sum of the specific volumes of its constituents (of the atomic
volumes), and that every element has a definite atomic volume in its compounds."
From this it would follow that : (i) Isomeric compounds possess approxi-
mately like specific volumes ; (2) like differences in specific volumes correspond
to like differences in composition.
The more recent researches (Lossen and others (A. 214, 81, 138 ; 221, 61;
224, 56 ; 225, 109 ; 233, 249, 316 ; 243, i) ; R. Schiff (A. 220, 71, 278) ; Horst-
mann (B. 19, 1579; 20, 766 and 21, 2211, etc.), based upon an abundance of
material, and at the same time giving due consideration to the structural relations
of the carbon compounds, prove conclusively that the supposed regularities,
mentioned above, are unfounded. In fact, isomeric compounds do not possess
equal molecular volumes, and their atomic volumes are not constant. The
volume for the difference CH2 is not constant in the different homologous series,
nor is that of hydrogen (A. 233, 318 ; B. 20, 767), nor that of oxygen (A. 233,
322 ; B. 19, 1594). M. W. Richards has shown that the atomic volume is a
function of temperature and pressure, and probably, also, of electric potential
(Z. phys. Chem. 40, 169). For the molecular solution-volume, see Traube (A. 290,
43 ; B. 28, 2722).
Hence the molecular volumes do not represent the sums of the atomic volumes
(the latter are scarcely determinable), and the specific gravities and molecular
volumes depend less upon the volume of the atoms than upon their manner of
linkage and upon the structure of the molecules. Therefore, to deduce regularities
in the specific volumes it is first necessary to consider carefully the chemical
structure of the compounds. In this connection the influence of the double
union of the C- atoms in the unsaturated compounds and the ring-linkage
46
ORGANIC CHEMISTRY
in the benzene derivatives, is significant. Assuming that the molecular volume
of hydrogen is known and is equal to 5*6, it becomes possible to calculate the
molecular volume of an unsaturated olefine compound if the molecular volume
of the corresponding saturated paraffin body is known. Thus, pentane =117-17 ;
therefore amylene =117-17-2 X5'6 = io5'97- In fact- the molecular _ volume
of amylene equals 109-95. Consequently 109-95 — 105-97 =3'98--the increase
in molecular volumes caused by the double linkage in amylene (A. 220, 298 ;
221 104 • B 19, 1591 ; 20, 779). The divalent union is therefore less intimate
(pp.* 2 1, 35), and' the unsaturated compounds consequently show a greater heat
of combustion (A. 220, 321).
In the conversion of benzene hydrocarbons into their hexahydndes there is an
increase in volume which is three times as great as in the conversion of the defines
into their corresponding paraffins. This would emphasize the theory that in
the benzene nucleus there are three doubly-linked
carbon atoms. The specific gravities of the benzene
hexahydrides are notably greater (consequently the
molecular volumes are smaller) than those of their
corresponding olefines, and that accounts for the fact
that in the ring-linking of the C- atoms in the
benzene nucleus there is an appreciable contraction
in volume (A. 225, 114 and B. 20, 773); Horstmann
(B. 21, 2211) ; Neubeck (Z. phys. Chem. 1, 649).
Schroeder determined the specific volumes of a
number of solids (B. 10, 848, 1871 ; 12, 567, 1613 ;
14, 21, 1607, etc.).
In determining the specific gravity of liquid com-
pounds, a small bottle — a pyknometer — is used, of
which the narrow neck carries an engraved mark.
More complicated apparatus, such as that designed by
Bruhl, based on Sprengel's form, is employed where
greater accuracy is sought (A. 203, 4) (Fig. 7). De-
scriptions of modified pyknometers will be found in
Ladenburg's Handworterbuch, 3, 238. A convenient
form by Ostwald is described in J. pr. Ch. 16, 396.
To obtain comparable results, it is recommended to
make all determinations at a temperature of 20° C.,
and refer these to water at 4° and a vacuum. If m represents the weight of
substance, v that of an equal volume of water at 20°, then the specific gravity at
20° referred to water at 4° and a vacuum (with an accuracy of four decimals),
may be ascertained by the following equation (A. 203, 8) : —
FIG. 7.
To find the specific volumes at the boiling temperature, the specific gravity
at some definite temperature, the coefficient of expansion and the boiling point
must be ascertained ; with these data the specific gravity at the boiling point
is calculated, and by dividing the molecular weight by this, there results the
specific or molecular volume. Kopp's dilatometer (A. 94, 257), Thorpe (J. Ch. S.,
37, 141), Weger (A. 221, 64), is employed in obtaining the expansion of liquids.
For a method of obtaining the direct specific gravity at the boiling point, see
Ramsay (B. 12, 1024), Schiff (A. 220, 78; B. 14, 2761), Schall (B. 17, 2201).
Neubeck (Z. phys. Ch., 1, 652).
Kanonnikow, as well as Kopp and his followers, employed the " true density "
in his calculations, not the figure as found directly. This he took as being the
reciprocal of Lorenz's refraction constant, since, according to the Clausius and
Mosotti theory, it constitutes the fraction of the total volume of a body which is
actually occupied by the molecules themselves (C. 1899, II. 858 ; 1901, I. 1190).
| 3. MELTING POINT (FUSION POINT BP.)
Every pure compound, if at all fusible or volatile, exhibits a
definite melting temperature. It is customary to determine this for
MELTING POINT (FUSION POINT BP.) 47
the characterization of the substance, and as a test of its purity. The
melting point of a pure compound is not changed by recrystallization.
The slightest impurities frequently lower the melting point very con-
siderably, whereas when foreign substances are present in larger
amounts the melting point is irregular and not well denned — i.e. there
is not a definite melting point. If two different substances have the
same melting point, a mixture of them will show a considerably
lowered melting point. The converse of this is of importance when
establishing the identity of two bodies — the mixture must have the
same melting point as each of the separate substances. Pressure
influences the melting point to a very slight degree.
In many crystalline carbon compounds a double melting point is observed.
When heated, the substance first melts to a doubly refracting, turbid " crystalline
liquid " (Li), which becomes clear and isotropic at a higher temperature (La, the
" clearing point "). On cooling the reverse order of changes may be observed :
LI L8
Solid crystals —, " Crystalline liquid " ^> Amorphous liquid.
The phenomenon apparently depends on chemical constitution, and is observed
mainly in aromatic compounds, chiefly acids, acid esters, ketones, and phenolic
ethers, which belong to the azoxy- or azo- series, or which contain the group
ArC-NAr
or ArC=NAr; and also in the cholesterol compounds, etc. (see
V
B. 39, 803, bibliography; Z. phys. Ch. 57, 357).
Determination oj the Melting Point. — The most accurate method would be to
immerse the thermometer in the molten substance ; this, however, would require
large quantities of material (Landolt, B. 22, R. 638).
Ordinarily, a small quantity of the finely pulverized material is introduced
into a capillary tube, closed at one end, which is attached to a thermometer, for
instance by a thin platinum wire, in such a way that the thermometer and capillary
tube are'on the same level. Alternatively, the substances may be pressed between
two cover glasses (C. 1900, I. 241). A beaker containing sulphuric acid or liquid
paraffin is used to furnish the heat, which is kept uniform throughout the liquid
by agitation with a glass stirrer. A long-necked flask, containing sulphuric
acid, is sometimes employed, in which a test tube is inserted or fused : in the
latter case it is necessary that the flask should be provided with a side-tubulure
(Fig. 8) (B. 10, 1800; 19, 1971 ; 5, 337 ; C. 1900, II. 409).
When the mercury thread of the thermometer extends far above the surface
of the bath, it is necessary, in accurate determinations, to introduce a correction,
by adding the value n(T— t) 0-000154 to the observed point of fusion, where n
is the length of the mercury column projecting beyond the bath expressed in
degrees of the thermometer, T is the observed temperature, and t the tempera-
ture registered in the middle of the projecting portion of the mercury column;
0-000154 is the apparent coefficient of expansion of mercury in glass (B. 22,
3072 : Literature and Tables). After the melting point has been approximately
determined with an ordinary thermometer a more accurate determination may be
made by introducing a shorter thermometer, divided into fifths, with a scale carry-
ing a limited number of degrees (about 50°). (See Fig. 8.)
The lack of agreement between the melting points of the same compound as
determined by different workers, is often sufficient to prevent identification. This
is not so much due to the thermometers as to the manner in which the deter-
mination is made. By rapid heating the mercury of the thermometer will not
have time to assume the fusion temperature. In the region of the melting point
the heat must be moderated so that during the course of the fusion the thermometer
rises very slowly. Far more concordant figures might be obtained if a general
use of short-scale thermometers were adopted and the time agreed upon for the
mercury of the thermometer to rise through one degree of the scale during the
48
ORGANIC CHEMISTRY
observation. For the determination of low melting points by means of the
air thermometer, see B. 26, 1052; B. 33, 637. For the determination of the
melting points of- organic bodies fusing at
high temperatures, see B. 28, 1629 ; at red-
heat, B. 27, 3129; of coloured compounds, B. 8,
687 ; 20, 3290.
Regularities in Melting Points. — (i) In the
case of isomers it has been observed that
the member possessing the most symmetrical
structure generally shows the highest melting
point ; for instance, among the aromatic series,
para-compounds melt at a higher temperature
than ortho- or meta-compounds. (2) Of the
alkyl esters of the carboxylic acids those with
the methyl residue have a higher melting point
than that of the next homologues (see oxalic
esters) . (3) In homologous series with like link-
ages the melting point alternately rises and falls
(see saturated normal aliphatic mono- and dicar-
boxylic acids, B. 29, R. 411 ; C. 1900, 1. 749). The
members, having an uneven number of carbon
atoms, have the lower melting points (Baeyer,
B. 10, 1286). This is also true of acid amides
having from 6 to 14 carbon atoms (B. 27, R. 551),
and for the normal primary diamines (C. 1900,
II. 1063 ; 1901, I. 610, etc. ; Z. phys. Ch. 50,
43). (4) In the case of the benzene nitro-
compounds and their derivatives — the azoxy-,
azo-, hydrazo-, and amido- bodies — as well as
the corresponding diphenyl compounds, it has
been observed that as oxygen is withdrawn
the melting point rises until the azo-derivatives
are reached, when it descends to the amido-
bodies (G. Schultz, A. 207, 362). To all these
regularities among melting points there exist
FIG. 8. numerous exceptions (Graham-Otto, Lehrbuch
der Chemie, Vol. I. part 3 (1898), p. 505;
Franchimont, C. 1897, II. 256). For the melting points of mixtures, see B.
29, R, 75-
4. BOILING POINT; DISTILLATION
The boiling points of carbon derivatives, which are volatile without
decomposition, are as important for the purpose of characterization as
the melting points. In case ef the latter the influence of pressure is
so slight that it can be neglected, but the former vary very markedly
when comparatively inappreciable changes in pressure occur. Hence in
stating a boiling point accurately it is necessary to add the pressure
at which it was observed. When the quantity of material is ample
the boiling point is determined by distillation. For the determination
of the boiling points of very small amounts of liquids, see B. 24, 2251,
944 ; 19, 795 ; 14, 88.
Distillation under Ordinary Pressure. — For this purpose a special flask is
employed, the long neck of which is provided with a side tube pointing downwards
at an angle. The neck of the flask is closed with a stopper, bearing a thermometer.
It must not be forgotten that very frequently the vapours of organic substances
attack ordinary corks or those of rubber, therefore the exit tube should be placed
a considerable distance from the end of the neck ; or the neck may be narrowed
at the upper end and the thermometer held in position by means of a piece of
india-rubber tubing passed outside it. The mercury bulb of the thermometer
BOILING POINT; DISTILLATION
49
should be slightly below the level of the exit tube in the neck of the flask. The
latter should be at least one-half filled with the liquid to be distilled.
If the thermometer is not wholly immersed in the vapour, the external mercury
column will not be heated to the same degree as that on the interior, hence the
recorded temperature will be less than the true one. The necessary correction is
the same as that which has already been given for the melting point. By using
a shorter thermometer with a scale not exceeding 50°, which can be wholly
surrounded by the vapour, the correction becomes unnecessary.
In general, when the boiling point " under ordinary pressure " is recorded,
it is understood to mean at 760 mm. of mercury. If the barometric column does
not indicate this amount during the distillation, a second correction is necessi-
tated (B. 20, 709 ; Landolt-Boernstein, Tabellen, 3rd edition, 1905, p. 177). To
avoid this it is advisable to adjust the pressure in the apparatus to the normal,
for which purpose the regulators of Bunte (A. 168, 139) and
Lothar Meyer (A. 165, 303) are suitable.
Distillation under Reduced Pressure* — Attention has already
been directed to the great variation in boiling points with
variation in temperature. Many carbon derivatives whose
decomposition temperature, at the ordinary pressure, is lower
than that of their boiling points, can be boiled under reduced
pressure at temperatures below the point at which they break
down. Distillation under reduced pressure is often the only
means of purifying liquids which decompose when boiled at
the ordinary pressure, and which cannot be crystallized. This
method is of
primary import-
ance in scientific
research in the
laboratory, and
is rapidly being
introduced into
technical opera-
tions with much
success.
Distillation
under reduced
pressure of easily solidifying bodies has been facilitated by the
introduction of flasks to which receivers are fused or ground in
(Fig. 9). The thermometer is introduced into a thin- walled tube
drawn out into a capillary, the other end of which is closed
FIG. 9. with rubber tubing and a clip. A slow current of gas is drawn
through the liquid during distillation, and in this way bumping
is avoided. The distillation flask is best heated in a bath. Usually the pressure
is lowered by means of a water pump, but when it is desired to distil at
pressures lying near the absolute vacuum, it will be found advantageous to use
a Sprengel mercury pump, which is set into motion, according to Babo's
method, by means of a water suction pump ; compare Kahlbaum (B. 27, 1386) ;
F. Krafft and H. Weilandt (B. 29, 1316) ; Precht (B. 29, 1143).
A still simpler method of attaining very low pressures consists in the employ-
ment of liquid air. A vessel, containing very finely divided pure blood-charcoal,
or cocoanut charcoal, is interposed between the apparatus illustrated in Fig. 9
and the air pump. On cooling it with liquid air the small amount of gas left in
the apparatus condenses in the charcoal, and the pressure falls to a fraction
* Compare Anschiitz and Reitter, Die Destination unter vermindertem
Druck im Laboratorium, 2nd ed., 1895, Bonn. The tables in this book record
the boiling points of over 400 inorganic and organic substances under reduced
pressure. George W. Kahlbaum, Siedetemperatur und Druck, Leipzig, 1885.
Dampfspannkraftsmessungen, Basel, 1893. Meyer Wildermann, Die Siedetemper-
aturen der Korper sind eine Funktion ihrer chemischen Natur (B. 23, 1254,
1468). W. Nernst and A. Hesse, Siede- und Schmelzpunkte, Braunschweig,
1893-
VOL. I. K
5o ORGANIC CHEMISTRY
of a millimetre. If the apparatus is filled beforehand with COa, the charcoal
can be omitted (B. 38, 4149). , CJ .... .QK
For distillation under any pressure, the apparatus of Staedel (A. 195, 218 ;
B 13 839) and Schumann (B. 18, 2085), may be used. For mercury thermometers
registering temperatures to 550°, see B. 26, 1815 ; to 700°, B. 27, 470.
Fractional Distillation. — Liquids having different boiling points can be
separated from mixtures by fractional distillation— an operation that is per-
formed in almost every distillation. Portions boiling between definite tempera-
ture intervals (from 1-10°, etc.) are collected separately and subjected to repeated
distillation, those portions boiling alike being united. To attain a more rapid
separation of the rising vapours, these should be passed through a vertical tube,
in which the vapours of the higher boiling compound condense and flow back,
as in the apparatus employed in the rectification of spirit or benzene. To this
end there is placed on the boiling flask a so-called fractionating column of Wiirtz.
Excellent modifications of this have been described by Linnemann, Le Bel,
Hempel Young, and others. For the action of these "heads," see A. 224,
259 ; B. 18, R. ioi, and A. 247, 3 '. B. 28, R. 352, 938 ; 29, R. 187. The action
of these fractionating columns is increased if enclosed by a highly evacuated
jacket (B. 39, 893, footnote).
Relation of Boiling Point to Constitution* — (i) Generally the boiling point
of members of a homologous series rises with the increasing number of carbon
atoms. (2) Among isomeric compounds of equal carbon content, that possessing
the more normal structure boils at a higher temperature. The addition of the
methyl groups depresses the boiling point. It is noteworthy that the lowest
boiling isomers possess the greatest specific volume (B. 16,2571). (3) Unsaturated
compounds boil at a higher temperature than those which are saturated. (4) The
substitution of a hydrogen atom by a hydroxyl group raises the boiling point
about 100°.
The connection existing between the boiling points and chemical constitution
of the compounds will be discussed later in the several homologous groups'.
5. SOLUBILITY
The hydrocarbons and their halogen substitution products are
either insoluble, or only very slightly soluble, in water. They dissolve,
however, very readily in alcohol and in ether, in which most other
carbon derivatives are also soluble.
Ether, but slightly miscible with water, is employed to extract many substances
from their aqueous solutions, separating funnels being used for this purpose.
The more oxygen a compound contains, the more readily soluble is it in water ;
especially is this true when several of the oxygen atoms are combined with
hydrogen, i.e. when hydroxyl groups are present in the organic compound.
The first members of homologous series of alcohols, aldehydes, ketones, and
acids are soluble in water, but as the carbon content increases, the hydrocarbon
character, in relation to solubility, becomes more and more evident, and the
compounds become more and more insoluble in water.
In addition to water, alcohol, and ether, other solvents are employed as
solvents, such as carbon disulphide, chloroform, carbon tetrachloride, methylal,
acetone, glacial acetic acid, ethyl acetate, benzene, toluene, xylene, aniline,
nitrobenzene, phenol, etc. Light petroleum spirit, derived from American
petroleum, is especially valuable ; it is composed of lower paraffins, and is often
used to separate compounds from solvents with which it is miscible, because
very many organic substances are insoluble or dissolve with difficulty in it.
The solubility of a compound is dependent upon the temperature, and
is constant for a definite temperature. This means is frequently employed for
purposes of identification.
* On the connection between the boiling point and the chemical constitution
of a substance, as known at present, see Graham-Otto, Lehrbuch der Chemie,
Vol. I. part 3, P. 535 (1898) ; also Menschuthin, C. 1897, II. 1067.
OPTICAL PROPERTIES 5I
For the regularities among the solubilities of isomeric carbon derivatives,
consult Carnelley, Phil. Mag. [6] 13, 180; Carnelley and Thomson, J. Ch. S 53*
801.
For apparatus suitable for determining solubility, see V. Meyer, B. 8. 098 and
Kohler, Z. anal. Ch. 18, 239 ; B. 30, 1752.
6. OPTICAL PROPERTIES
Colour. — Most organic compounds are colourless, many are coloured ;
e.g. iodoform is yellow, whilst carbon tetraiodide is dark red. The
presence of certain atomic groups is connected with definite colours,
particularly in the case of the aromatic derivatives. The nitro-
bodies, for example, are more or less yellow, whilst the azo-
derivatives vary from orange to red, etc. The colour of the solution
of coloured substances depends to a large extent on the nature of the
solvent (B. 27, R. 20 ; 39, 4153).
Dye-stuffs. — Many coloured compounds, belonging almost ex-
clusively to the aromatic series, possess the property of dyeing
vegetable or animal fibres, either directly or through the agency of
mordants.
According to O. N. Witt, an aromatic substance behaves as a dye when it
includes a chromophoric group, e.g. NO2, N2, etc., as well as an auxochrome group,
such as an OH or amino -group, in its composition. The latter occupy the ortho-
or para- position to the chromophor. A substance containing a chromophoric
group alone is called a chromogen (B. 9, 522 ; 35, 4225 ; 36, 3008).
Fluorescence. — This property, like that of colour, results from the presence
in the molecule of certain fluorophoric groups (R. Meyer, B. 31, 510 ; C. 1900, II.
308 ; Chem. Ztg. 29, 1027).
Refraction. — The carbon compounds (like all transparent sub-
stances) possess the power of refracting light to a varying degree.
The coefficient of refraction or refractive index (n) for homogeneous light passing
from medium I into medium 2, represents the ratio of the velocities of propa-
gation vl and », in both media ; «=— . For single refracting media, in which
similar optical behaviour is observed in all directions (a condition which is seldom
found in crystals) n is independent of the direction of the incident light, so that
if » and r are the incident and refractive angles «=^l=?m-?, a constant number
for light of a definite wave-length.
Specific Refractive Power. — The refractive index (n) varies with the tempera-
ture, consequently also with the specific gravity of the liquid.
Their relation to each other is approximately expressed by the equation ;
~ = const. or ^ ~ . ^ = const.*
d
(Gladstone's formula). (Lorenz and Lorentz's formula).
»-formula. n*-formula.
where d is the sp. gr. of the liquid, determined at the same temperature as the
refractive index. The constant remains practically unchanged for any tempera-
ture.
Molecular Refractive Power or Molecular Refraction is the specific refractive
* See Graham-Otto, Lehrbuch der Chemie, Vol. I. part 3, p. 567, 1898,
52 ORGANIC CHEMISTRY
power of a substance multiplied by its molecular weight. It is represented by
M or |H, according to whether Gladstone's or the nz formula is adopted :
It is immaterial which of the two formulae is employed in the examination
of stoichiometrical questions, so long as fluid substances are referred to. In a
comparison of liquids with their vapours the n9 formula only can be used, and
it is also to be preferred when dealing with aromatic substances.
The molecular refraction of a liquid carbon compound is equal to the
sum of the atomic refractions r, r', r" :
M = ar + 6/ + cr*,
in which a, b, c, represent the number of elementary atoms in the
compound. The atomic refractions of the elements are deduced from
the molecular refractions of the compounds obtained empirically, in
the same manner as the atomic volumes are obtained from the mole-
cular volumes. Whilst it was formerly assumed that but one atomic
refraction existed for each element in its compounds, later researches
have proved that only the univalent elements have a constant atomic
refraction, and that of the polyvalent elements, e.g. oxygen, sulphur,
carbon, is influenced by their manner of union.
This is seen in the rise in the molecular refraction by a constant quantity,
amounting to 2-4 for the w-formula, and 1-84 in the case of the «2-formula, for
each double bond of a carbon atom. A treble bond possesses the w» value of
approximately 2-2.
The refraction is determined either for the yellow sodium line (the D line in
the solar spectrum), or for the red hydrogen line Ha (C in the solar spectrum).
These values are affected by the disturbing influence of " dispersion" and a
refractive index free from this factor has not yet been developed (see Dielectric
Constant, p. 53). The molecular refraction ascertained by means of the above
formula from the observed values of the refraction and density, can be compared
with that calculated by the addition of the particular atomic refractions, as
given in the accompanying table.
-
—
Gladstone's formula.
Lorenz's formula.
'a
fD
r
a
fD
Carbon (single bond) ....
Hydrogen
C'
H
O'
o<
0*
Cl
Br
I
5-oo
1-30
I 2-80
3-40
979
15-34
24-87
2-4
471
1-47
2-65 1
3'33
10-05
15-34
25-01
2-64
2-365
1-103
1-506
1-655
2-328
6-014
8-863
13-808
1-836
2-22
1
2-50I
I-05I
I-52I
1-683
2-287
5-998
8-927
14-12
I-7I
Oxygen (hi hydroxyl) . . ,
Oxygen (in ethers)
Oxygen (carbonyl)
Chlorine
The atomic refraction of nitrogen in its various combinations has been minutely
investigated by Bruhl, but final results have not, as yet, been attained.
It is, therefore, obvious that important data relating to the manner
of union of the atoms in the molecule of a carbon compound can be
OPTICAL PROPERTIES 53
obtained from the molecular refractions. When the observed mole-
cular refraction is in excess of the calculated value, the presence of a
double or treble bond is indicated. Thus the greater molecular
refraction (by 3 X 178 = 5-34 units) of the benzene bodies, confirms
the view, previously deduced from chemical facts, that there are
present in the benzene nucleus three doubly-linked carbon atoms.
Among the terpenes the change from a ring formation to an open
chain with a double bond can be followed (B. 20, 2288 ; 22, 2736 ;
23, 855 ; 24, 656, 2450 ; 25, 2638). In many cases among the sub-
stances referred to by Laar as being tautomeric, it has been possible to
ascertain whether they exist in the enol- or keto- form (B. 25, 366,
3078 ; 38, 1868). However, the regularities noted above only hold
good for bodies with slight dispersive power, such as the fatty bodies.
In the case of substances possessing a greater dispersive power than
cinnamyl alcohol, the molecular refraction is valueless for the deter-
mination of chemical structure (B. 19, 2746 ; 24, 1823).
On the employment, for the elucidation of stoichiometrical problems, of the
molecular dispersion of bodies, i.e. the difference between the refractions measured
with blue and red hydrogen lines, see Bruhl (Z. phys. Ch. 7, 140).
The refraction stere of /. Traube is the quotient obtained by the division
of the molecular refraction by the number of atomic valencies. Within certain
limits it approximates to a constant (0-787) which is of special significance in the
theory of valency (B. 40, 130, 723).
The Abbe total refractometer, and Pulf rich's total reflectometer are much more
convenient than the spectrometer for rapid and sufficiently accurate working (Z.
phys. Ch. 18, 294 ; B. 24, 286)."
Dielectric Constant.- — The electrostatic force by which two electrified
bodies affect one another varies with the nature of the insulating " dielectric
medium " which separates them. Taking air as unity, the measurement made
with another substance under similar circumstances gives the dielectric constant
of that medium. This value, usually indicated by A-, has been taken for a large
number of carbon compounds ; * for example : —
K K
Gases and Vapours, about . i-o Fatty Acids, about . 2-6-7-0
Liquid Hydrocarbons . 2-0-2-5 Fatty Acid Esters . 5-9
Carbon Bisulphide . . .2-6 Fatty Alcohols . . 16-35
Ethyl Ether 4-5 Water 80
The electromagnetic theory of light is based on the fundamental principle
that light and electromagnetic waves are of the same nature, differing from one
another only in length. The refractive index, for an infinitely long wave can
be closely connected to the dielectric constant, by the relation A//T= «o. The
determination of the dielectric constant thus supplies directly a value for the
refractive index free from dispersion, analogous to the Lorenz formula (p. 51),
P . ±^J . _1 = const.
K + 2 d
The values obtained in investigations so far carried out f have not led in
general to a good correspondence with those derived by optical methods, whilst
the optical molecular refraction measurements show an additive character (at
least for compounds of similar constitution), the values obtained by electrical
methods are influenced by insignificant differences in constitution of each sub-
stance. In this case there is no possibility of calculating " atomic refractions,"
* On the method of measurement for chemical purposes, see Nernst (Z. phys.
Ch. 14, 622 ; 24, 21) ; Wied (A. 57, 215 ; 60, 600) ; Drude (Z. phys. Ch. 23, 267).
f Landolt and John (Z. phys. Ch. 10, 289). See also Graham-Otto, Lehrb.
der Chemie, I. part 3, p. 650, 1888.
54 ORGANIC CHEMISTRY
but rather to trace and disclose differences in constitution by electrical means,
for which purpose it is of great assistance. Under certain circumstances the
attendant phenomenon of anomalous electrical absorption is to be observed, i.e.
the partial change of electrical into heat energy. Almost all the non-conducting
carbon compounds which give rise to this absorption contain the hydroxyl group.
On this observation is based a method of detecting and demonstrating the mutual
change of keto- and enol- forms (Drude, B. 30, 94° ; z- PhYs- Ch- 23, 3°8, 318).
Further progress in this investigation will doubtless yield important results.
The vapours of many groups of aliphatic and specially aromatic bodies
absorb Tesla currents at ordinary pressure and change them into light waves.
Such substances, for example, are the primary aromatic amines, and the simple
aliphatic aldehydes and ketones. In the latter case the keto- group seems to be
the vehicle of the luminescence, at any rate neither the vapours of paraldehyde
nor of acetaldehyde become illuminated (H. Kauffmann, B. 35, 473).
1 Optical Rotatory Power,* Rotation of the Plane of Polarization
by Liquid or Dissolved Carbon Compounds. — Biot, in 1815, observed
that many naturally occurring bodies such as the sugars, the terpenes,
and camphors, were capable of rotating the plane of polarized light.
He also showed, in 1817, how the vapours of turpentine also deviated
the plane of polarization, and concluded that this power was a property
of chemical molecules. Such bodies are termed optically active carbon
compounds.
Specific Rotatory Power [a]. — The angle of rotation o is proportional to the
length / of the rotating column (usually expressed in decimetres) ; hence the ex-
pression j is a constant quantity. To compare substances of different density, in
which very unequal masses may be contained in this column, they must be referred
to a like density, and hence the rotation must be divided by the sp. gr. of the
substance at a definite temperature. The expression
or «=
is called the specific rotatory power and is designated by [o]D or [a]jf according as
the rotation is referred to the yellow sodium line D or the " transitional colour " j.
For solid, active substances, in an indifferent solvent, the equation employed is
I00a
W=pld'
where p represents the quantity of substance in 100 parts by weight of the
solution, and d represents the specific gravity of the latter.
This specific rotatory power is constant for every substance at a definite
temperature ; it varies, however, with the latter, and, in the case of solutions,
with the nature and quantity of the solvent. So much is this the case, that
under various conditions the angle of rotation for one and the same substance
can become zero or even change in sign. Therefore, in the statement of the
specific rotatory power of dissolved substances the temperature and percentage
strength of the solution are always given.
In many cases the addition of substances such as salts, etc., causes a change
in the rotation. Such active bodies, including tartaric acid, malic acid, mandelic
acid, and others, which contain an alcoholic hydroxyl group, are powerfully
influenced by the addition of alkali borates, molybdates, tungstates, and uranates.
The phenomenon depends apparently on the formation of complex combinations
(B. 38, 3874, etc.), and can sometimes be used to increase the rotation of active
substances, of which the rotatory power would otherwise be too small to be
measured alone, either on account of specific value being insignificant or because
the solution employed is too weak. (See Landolt, previous reference, footnote,
p. 220 ; Walden (B. 30, 2889).)
* Landolt, Das optische Drehungsverm gen organischer Substanzen und
die practische Andwendung derselben, 2nd edition, Braunschweig, 1 898. Walden,
Ueber das Drehungsvermogen optisch aktiver Korper, B. 38, 345.
OPTICAL PROPERTIES 55
Molecular Rotatory Power is the product of the specific rotatory power [a]
and the molecular weight P. As these values are usually high, the molecular
weight is divided by 100.
100
The most suitable apparatus for measuring rotation are described in the above-
mentioned work of Landolt (p. 54, footnote).
In 1848 Pasteur demonstrated that in optically active substances, such as
tartaric acid and its salts, the rotatory power is intimately connected with the
crystalline form, and is usually connected with the presence of hemihedral faces.
In the discussion of the stereochemical or spacial theories, reference was made to
the fact that Pasteur considered the asymmetric structure of the molecules of
optically active carbon compounds to be the cause of their remarkable action
upon polarized light.
According to the theory of van 't Hoff and Le Bel, the activity of the carbon
compounds is dependent upon the presence of asymmetric carbon atoms or on the
asymmetric arrangement of atoms attached to a carbon skeleton in space (p. 30).
So far as they have been investigated, all optically active carbon compounds
contain one or more asymmetric carbon atoms. However, there are many
Jompounds containing such atoms, which, when they exist as liquids, or when
in solution, have no effect upon polarized light. This is true when two molecules
of opposite but equal rotatory power unite to form a molecule of a physical,
polymeric compound, e.g. inactive lactic acid, inactive malic acid, inactive
asparagine, inactive aspartic acid, racemic acid, etc. ; also, when the half of a
molecule neutralizes the rotation produced by the other half, as in mesotartaric
acid.
It has also been shown that in the conversion of optically active bodies into
their derivatives the activity continues so long as the latter contain asymmetric
carbon atoms ; when the asymmetry disappears, the derivatives become inactive.
The two active tartaric acids yield two active malic acids ; active asparagine
yields active aspartic acid, active malic acid, etc., whilst the symmetrical succinic
acid that is obtained by further reduction is inactive.
If various groups, each containing an asymmetric carbon atom, be introduced
into a molecule, the final rotation will be the algebraic sum of the rotations of
the single groups : see especially, Guye (C.r. 119, 953 ; 120, 632 ; 121, 827 ; 122,
932) ; and Walden (Z. phys. Ch. 17, 721).
By changing or substituting a single group or element, connected with an
asymmetric C atom, the rotatory power is often very considerably influenced ;
as, for instance, by the production of an ethylenic linkage or by ring-formation
(C. 1903, II. 116 ; 1905, II. 31 ; A. 327, 157) ; or when alkyl groups are intro-
duced into NH or OH groups (B. 34, 2420 ; C. 1905, II. 455). In the case of
malic acid the optical antipodes can be transformed into one another by a con-
tinuous series of changes ; 1-malic ester, with PC16, gives d-chlorosuccinic ester, the
acid of which with silver oxide yields d-malic acid. Conversely, d-malic ester, with
PC15, gives 1-chlorosuccinic ester, of which the acid can be converted into 1-malic
acid. Similarly, 1-bromo- or 1-chlorosuccinic acid, acted on by ammonia in methyl
alcohol solution, yields d-aminosuccinic acid, which is changed into d-malic
acid by barium hydroxide. Finally, the halogen substitution products of the
active succinic acids, when acted on by potassium hydroxide instead of silver
oxide, have their halogens replaced by hydroxyl to form the hydroxy-acids,
possessing not the same but the opposite direction of rotation (Walden, B. 30,
3146). Similar " reversed rotations " can be observed among the simple amino-
acids, such as alanine and leucine (q.v.) (B. 39, 2895 ; 40, 1051).
Asymmetric compounds prepared in the laboratory from inactive substances
are inactive. This results from the simultaneous formation in equal quantities
of the two optical antipodes which manifest a tendency to combine to form the
inactive, physically polymeric molecules. Asymmetric syntheses, i.e. the pre-
paration of one active body from an inactive one without the intermediate
formation of a racemic body, can, however, sometimes be effected, by combining
the inactive compound with an active one and then carrying out the change
which will produce the active substance sought: methyl ethyl malonic acid
combines with the active alkaloid brucine forming an acid salt. On heating, CO2
escapes, and when the resulting brucine methyl acetyl acetate is decomposed with
56 ORGANIC CHEMISTRY
hydrochloric acid, optically active methyl ethyl acetic acid is obtained (B. 37,
1368 ; C. 1906, I. 1613 ; II. 53)-
Racemic Bodies. — The typical substance, racemic acid, has given its name to
all similar inactive mixtures of the two optical antipodes. The racemic sub-
stance differs from its components also in that it forms crystals which do not
give rise to enantiomorphic modifications. The density of the racemic body is, as
a rule, greater and its solubility less than the corresponding active substances,
but not always ; similarly there is no general rule for the relative position of the
melting point.
When the crystalline form of an inactive substance cannot be observed with
accuracy, as of ten happens, and when at the same time, the melting point lies lower
than that of either of the optically active components, then doubt may arise
whether it is a true racemate or a mixture of equal quantities of the optical
antipodes. A variety of tests can be applied. The melting point may be taken
after a small quantity of one of the active components has been added to the
inactive substance. The composition may be determined, as well as the optical
behaviour, of a concentrated solution of the inactive body as compared with that
of a mixture of the inactive and one active substance. If the addition of the
active body causes a lowering of the melting point of the inactive substance,
a change in the concentration and in the optical activity of the saturated solution,
then the substance is a racemic one ; if, on the other hand, the melting point
rises, and the concentration and inactivity of the solution are unaltered, then
the inactive body is a mixture.
The formation of a racemic substance is dependent on the temperature.
Above or below its transformation temperature the body may be a racemic body
or an enantiomorphic mixture. The results of the above experiments hold good,
then, only for the particular temperature at which they are carried out, and a
series of experiments over a wide range of temperature is necessary to obtain
a complete insight into the matter.
These practical tests are, in part, the direct result of the considerations on
heterogeneous equilibrium as put forward in Gibb's phase rule (van 't Hoff, B. 31,
528 ; Laderiburg, B. 32, 1822 ; Roozeboom, Z. phys. Ch. 28, 494, etc. Also B. 33,
1082).
Pseudo-racemic mixed crystals, although inactive, possess the form of the
active modifications, without, however, the hemihedric faces (J. Ch. S. 71, 889 ;
75, 42).
Resolution of Inactive Carbon Compounds into their Optically Active Com-
ponents.— The synthesis of optically active carbon compounds is easily realized
by direct methods, because it is possible to separate the dextro- and laevo-
rotatory components in an inactive molecule. The following methods, I, 2, and
5, were employed by Pasteur (1848) in his study of the racemates and racemic
acid. This classic investigation supplies the firm experimental basis for the
theory of stereochemistry or the space chemistry of carbon (p. 29).
Method i, based upon resolution by crystallization. — The substance itself, or
its derivatives with optically inactive compounds, is crystallized at varying
temperatures and from various solvents. In the case under consideration it
is possible to separate two substances showing enantiomorphous hemihedrism
by actually picking out those crystals exhibiting the particular forms. Thus,
from a solution of sodium ammonium racemate below 28° hemihedral crystals
of sodium ammonium dextro- and laevo-tartrates can be obtained (B. 19, 2148).
Method 2, dependent upon the formation of compounds with optically active
substances.— -Pasteur succeeded in separating d- and 1-tartaric acids through
their quinicine and cinchpnine salts. This was because these, being no longer
enantiomorphous, were distinguished by their varying solubility, and so could
be very easily separated from each other.
Ladenburg first used the latter method to resolve inactive bases by forming
salts of the latter with an active acid. It was thus that he decomposed synthetic
inactive coniine (a-n-propyl piperidine) by means of dextro-tartaric acid into
its active components, and completed the synthesis of the first optically active
vegetable alkaloid — coniine — which occurs in hemlock (q.v.).
The resolution of racemic substances does not always immediately result
from the combination with active bodies and the subsequent precipitation of
the more insoluble of the new compounds. Under certain conditions the racemic
OPTICAL PROPERTIES 57
body unites, as such, with the added active body, forming a semi-racemic compound
(such as strychnine racemate), which can only be decomposed into compounds of
its active components at a particular temperature (Ladenburg, B. 31, 1969 ; 32, 50).
Method 3, based on the formation of esters or amides between racemic and
optically active substances. — Racemic mandelic acid can be partially turned into
the 1-menthol ester, whereby the residue consists of an excess of 1-mandelic acid.
If 1-quinic acid be heated with rac. a-phenyl ethylamine, the dextro-rotatory
acid, which does not take part in the amide formations, remains behind (B. 38,
801).
Method 4. — Enzymes, such as maltase or emulsin, decompose racemic
glucosides (E. Fischer, B. 28, 1429).
Method 5. — On introducing some suitable fungus such as Penicillium glaucum
into an aqueous solution of an inactive mixture, capable of resolution, one modi-
fication of the mixture will be destroyed during the life-process of the fungus ; thus
racemic acid yields l-tartaric acid, inactive amyl alcohol yields d-amyl alcohol,
methyl propyl carbinol yields l-methyl propyl carbinol, propylene glycol yields
l-propylene glycol, etc.
One fungus may leave an optical modification untouched which another may
destroy.
Penicillium glaucum or Bacterium termo will leave d-mandelic acid from the
synthetic inactive racemic acid, whilst Saccharomyces ellipsoideus or Schizomycetes
leave the 1-acid untouched. For the literature of the resolution of racemic
compounds, see Landolt, Optisches Drehungsvermogen, etc., 2nd edition, p. 86,
1888.
Carbon compounds, in which an asymmetric carbon atom is not present,
could not be decomposed by these methods (A. 239, 164 ; B. 18, 1394).
Conversion of Optically Active Substances into their Optically Inactive Modifi-
cations.— Whilst soluble salts of optically inactive, resolvable carbon compounds
may be resolved by crystallization under proper conditions of temperature, many
others reunite to form a salt of the inactive body, especially if the latter dissolves
with difficulty. Solutions of laevo- and dextro-tartrate of calcium when mixed
yield a precipitate of calcium tartrate, which dissolves with difficulty. The free,
optically active modifications unite, as a rule, very easily when mixed in solu-
tion, to form the inactive decomposable modification, e.g. Ia3vo- and dextro-
tartaric acid yield racemic acid. The esters of these acids behave in a similar
manner : laevo- and dextro-tartaric methyl esters unite directly and in solution
to form racemic methyl ester (B. 18, 1397). Also, in energetic reactions, or
when heated, the active varieties rapidly pass into the inactive forms, e.g. dextro-
tartaric at 175° yields racemic acid, and at 165° mesotartaric acid. At 180°
dextro- and laevo-mandelic acids pass into inactive mandelic acid. Some optically
active halogen substitution products of carboxylic acids undergo auto-racemation,
even at ordinary temperatures (B. 31, 1416).
A corresponding behaviour is observed in the decomposition of albumins, when
heated with barium hydroxide, into inactive leucine, tyrosine, and glutamine,
whilst at a lower temperature hydrochloric acid produces the active modifications
(B. 18, 388). For an experimental explanation of the transformation of optically
active substances into their inactive modifications, compare A. Werner in R.
Meyer's Jahrbuch der Chemie 1, 130.
Magnetic Rotatory Power.* — Faraday, in 1846, discovered that trans-
parent, isotropic, optically inactive bodies were capable of rotating the plane
of polarized light when a column of the substance was brought into the magnetic
field, as, for example, when it was surrounded by an electric current. The
power of rotation only continued as long as these influences were active, and
was reversed when the position of the magnetic poles were reversed; this
distinguished magnetic rotatory power from the rotatory power of optically
active carbon compounds.
Specific magnetic rotatory power is the degree of rotation that the plane of
polarization of a ray of light undergoes when it passes through a layer of liquid
of definite thickness, exposed to the influence of a magnet. The unit of com-
parison is the rotation produced by a layer of water of the same temperature
and thickness when exposed to the same magnetic field.
* Graham-Otto, Lehrbuch der Chemie, Vol. I. part 3, p. 793, 1898.
58 ORGANIC CHEMISTRY
Molecular Magnetic Rotatory Power.— This is the degree of rotation produced
by columns of liquids chosen of such a length that similar cross-sections will each
contain a molecular weight of the substance. The unit in this case can also be
the molecular rotatory power of water.
W. H. Per kin, Sr., has investigated minutely the connection between the
magnetic rotatory power and the constitution of carbon derivatives. Numerical
relations between the increase of rotation and change of composition have been
established for many groups of aliphatic and aromatic compounds (C. 1900, I.
797 J 1902, I. 621). Deviations from the theoretical values are encountered
particularly in the reactive benzene substitution compounds (see Table, J. pr
Ch. [2] 67, 334).
7. ELECTRIC CONDUCTIVITY
Substances which are capable of conducting electricity arrange
themselves into two groups : conductors of the first class, or those
which conduct electricity without undergoing any change, and
conductors of the second class, known as electrolytes, in which con-
duction is only possible through the agency of the ions in which
the solutes separate when dissolved. The greater the conductivity
of a substance the less is the resistance to the passage of the current ;
in other words, the resistance is inversely proportional to the conduc-
tivity. The unit of measurement of resistance is the ohm — the resis-
tance of a column of mercury ro6 metres long, and I mm. in cross
section, at o° C.
Ostwald's investigations have demonstrated that the conductivity
of electrolytes is intimately related to chemical affinity, and forms a
direct measure of the chemical affinity of acids and bases. Therefore,
the determination of the conductivity of electrolytes (in aqueous
solution), to which all organic acids and their salts belong, is of great
interest and importance for all carbon derivatives.
Kohlrausch (Wied, A. 6, i) has suggested a very simple and accurate means of
determining the conductivity of electrolytes, which has been extensively applied
by Ostwald (J. pr. Ch. 32, 300, and 33, 352 ; Z. phys. Ch. 2, 561). (See also
C. 1900, I. 577.) It is dependent on the application of alternating currents,
produced by an induction coil, so that the disturbing influence of galvanic
polarization is avoided.
The conductivity of electrolytes is not referred to the percentage
content of their aqueous solutions, but (as the conductivity is deter-
mined by the equivalent ions) to solutions containing a gram-mole-
cule, or a gram-equivalent of substance in one litre. This value is
the molecular (or equivalent) conductivity of the substance (Z. phys.
Ch. 2, 567).
F. Kohlrausch and Holborn, in their book, "Das Leitungsvermogen der
Elektrolyte," refer the conductivity of a solution to a unit consisting of a column
i cm. long, and i cm.2 in section which has a resistance of I ohm. In this case
the conductivity becomes 10,600 times as great as the above. Also, they employ
the gram-equivalent in place of the gram-molecule, and the cubic centimetre
in place of the litre.
The strong acids have the greatest molecular conductivity, and are followed by
the fixed alkalies and alkali salts. Most organic acids, on the contrary (e.g. acetic
acid), are poor conductors in a free condition, whilst their alkali salts approach
those of the strong acids in conductivity. The molecular conductivity increases
by about 2 per cent, per degree rise of temperature. It also increases with
increasing dilution, and in the case of the poor conductors it is far more rapid
ELECTRIC CONDUCTIVITY 59
than with the good conductors ; in both instances it ultimately approaches
a maximum (limiting) value. With good conductors this is attained at a dilution
of about 1000 litres to the gram-molecule ; whilst with those poor in conducting
power it is only reached when the dilution is indefinitely large. In fact, in such
cases the conductivity is practically indeterminable.
An interesting observation in connection with the alkali salts of all
acids is the variable increase of the molecular conductivity with
increasing dilution. This is true both in the case of the strong and the
weak acids (most organic acids belong to the latter class), and it varies
according to their basicity. With sodium salts of monobasic acids,
this increase equals from 10-13 units, by dilution of 32-1024 litres for
the equivalent of substance ; for the salts of dibasic acids from 20-25
units, for those of the tribasic 28-31, for those of the tetrabasic about
40, and those of the pentabasic about 50 units.
Thus it may be seen that the increase in conductivity of acids, in
the form of their sodium salts, offers a means of determining the basicity
and, consequently, the molecular magnitude of acids (Ostwald, Z. phys.
Ch. 1, 74, 97 ; 2, 901 ; Walden, ibid., 1, 530 ; 2, 49).
If a certain quantity of an acid be neutralized with N/32 sodium
hydroxide solution, and the conductivity of the neutral salt be measured
before and after dilution to 32 times its volume, the difference of the
conductivities divided by 10 gives the basicity of the acid.
Molecular conductivity has acquired still greater importance by its
application to the measurement of the dissociation of the electrolytes ;
it is at the same time the measure of the reactivity or chemical affinity,
first, of acids, then bases, and, finally, of salts.
Arrhenius's electrolytic dissociation theory- maintains that in
aqueous solution the electrolytes are more or less separated into their
ions ; this would give a simple explanation for the variations of solu-
tions from the general laws of osmotic pressure, the depression of the
freezing point, etc. (see p. 16). The dissociation is also manifest in
the molecular conductivity, for the latter is directly proportional to
the degree of dissociation, the number of free ions and the speed of
migration of the free ions.
Molecular conductivity increases with dilution and dissociation. When the
latter is complete, it attains its maximum (^ ). The degree of dissociation (m)
(or the fraction of the electrolyte split up into ions) for any dilution is found
from the ratio of the molecular conductivity at this dilution (p) to the maximum
conductivity (for an indefinite dilution) :
The latter (/ZQQ ) cannot be directly measured in the case of free organic acids,
because most of them are poor conductors. But it can be obtained from the
molecular conductivity of their sodium salts, by deducting from their maximum
values the speed of migration of the sodium-ions (49 -2), and adding those of the
hydrogen-ions (352).
Since the molecular conductivity depends upon the dissociation of the
electrolytes into their ions, the effect of dilution must follow the same laws as
those prevailing in the dissociation of gases. This influence of dilution or volume
(v) upon the molecular conductivity, or the degree of dissociation (m) is, there-
fore, expressed in the equation :
m* =K
t;(i — m)
which represents the law of dilution advanced by Ostwald (Z. phys. Ch. 2, 36, 270).
60 ORGANIC CHEMISTRY
This law has been fully confirmed by the perfect agreement of the calculated and
observed values (van 't Hoff, Z. phys. Ch. 2, 777). In the case of strong electro-1
lytes, such as strong acids and bases, and most salts, the equation of Rudolphi
is preferable to that of Ostwald, even though it is empirical :
_ — — .
The value, K, is the same at all dilutions for every monobasic acid ; hence it is
a characteristic value for each acid, and is the measure of its chemical affinity.
The determination of these chemical affinity-constants by Ostwald for more than
240 acids, has proved that they are closely related to the structure and constitution
of the bodies (Z. phys. Ch. 3, 170, 241, 369). Literature : see Walden (Z. phys.
Ch. 8, 833). Affinity values of stereoisomeric compounds : Hantzsch and Miolatti
(B. 25, R. 844).
Addendum : Determination of affinity-coefficients : Conrad, Hecht, and
Bruckner (Z. phys. Ch. 3, 450 ; 4, 273, 631 ; 5, 289). Lellmann (B. 22, 2101 ;
A. 260, 269 ; 263, 286 ; 270, 204, 208 ; 274, 121, 141. 156). Nernst (R. Meyer's
Jahrbuch 2, 31).
|
HEAT OF COMBUSTION OF CARBON COMPOUNDS*
" The quantity of heat evolved in any chemical change is a measure
of the total work, both physical and chemical, expended." The
determination of the quantity of heat developed in complete combus-
tion is alone adapted for the determination of the energy content of
carbon compounds.
The heat of combustion of a carbon compound by the method of
Berthelot is determined by combustion with oxygen at a pressure of
25 atmospheres in a calorimetric bomb, lined internally with platinum
or enamel. Ignition is effected by means of an electric spark, or by
the incandescent products of combustion formed by a thin iron wire
heated electrically.
The method is so accurate that it can be employed for the detection
of quite small quantities of impurity in an organic compound, the heat
of combustion of which is known (J. pr. Ch. [2] 48, 452 ; Z. f. angew.
Ch., 1896, p. 486).
On the basis of the Hess-Berthelot principle : " The difference of
the heats of combustion of two chemically equivalent systems is equal
to the heat development which corresponds to the passage of the one
system into the other " : it is possible, knowing the heat of combustion
of a carbon compound to calculate its heat of formation. The heat of
combustion of the compound is deducted from the sum of the heats
of combustion of its elements.
The heat of combustion of methane equals 211-9 cal.
,, „ diamond-carbon is 94 cal., and
,, „ hydrogen equals 69 cal.
As the complete combustion of methane proceeds according to the equation :
CH4 + 2O2 = CO2 -f 2H2O,
then the heat of formation of this hydrocarbon, at constant pressure, would
be 20-1 cal. :
94 -f (2 X 69) —211 -9 = 20-1.
* Praktische Anleitung zur Ausfiihrung thermochemischer Messungen,
Berthelot, translated into German by Siebert, 1893. Grundriss der allg. Thermo-
chemie, Plank, 1893. Die Grundsatze der Thermochemie und ihre Bedeutung
fiir die theoretische Chemie, Hans Jahn, 2. Aufl. 1892. Grundriss der allg.
Chemie, Ostwald, 1889. Mecanique chimique, Berthelot, Paris, 1879.
ACTION OF HEAT 61
The development of methods for the determination of the heats of combustion
is due to the investigations of Favre and Silbermann, Thomsen, Stohmann, and
particularly of Berthelot. Stohmann especially determined the heat of com-
bustion of numerous carbon derivatives, and published a tabulated account of
the heats of combustion of organic bodies, made from 1852-1892 (Z. phys. Ch. 6,
334 I 10» 410)-
The regularities thus far observed are as follows : With the hydrocarbons of
the paraffin and olefine series the constant difference of CH2 in composition corre-
sponds to a constant difference of 158 cal. in the heat of combustion. Similar
relations occur in other homologous series.
The heat of combustion of the two isomeric propyl alcohols is almost the same,
consequently in the case of similar linkage-relations position-isomerism is without
influence upon the heat of formation and the heat of combustion. The difference
of 6 cal. in the heats of combustion of fumaric acid (320-1 cal.) and maleic acid
(326-3 cal.) is more striking if we grant similar linkage-relations in the two acids,
as is done by those who consider the difference between these two acids to be
solely a stereochemical one.
The passage from a double linkage to two single linkages, as well as from a triple
union to three simple unions is accompanied by considerable loss in energy. The
relation of the heats of combustion of aromatic substances to their hydride
derivatives is noteworthy. The differences of the heats of combustion of the
dihydrobenzenes and their corresponding unaltered benzenes is considerably
greater than the difference of the heats of combustion of the corresponding
tetrahydro- and dihydro-benzenes. It is to be noticed that there appears to
exist a quite small thermal difference between tLe olefine carboxylic acids and the
tetramethylene dicarboxylic acids, as, for example, acrylic and tetramethy-
lene dicarboxylic acids, cinnamic and truxillic acids (Z. phys. Ch. 48, 345),
as is also the case of the hexahydro- and tetrahydro-benzene derivatives. As
to the contradictory conclusions which have been deduced from these facts in
regard to the manner of union of the carbon atoms in the benzene ring, see A. 278,
115 ; B. 27, 1065 ; J. pr. Ch. [2] 48, 452 ; 49, 453.
The varying stability of the tri-, tetra-, and penta-methylene rings referred by
Baeyer to the varying ring-pressure (see the introduction to the carbocyclic
compounds) is indicated in the heats of combustion, whilst no difference
could be detected between the penta- and hexa-methylene rings. As an example
as to how far observations upon the mentioned carbocyclic compounds can be
applied to deductions upon constitution, it may be cited that the heat of combus-
tion of camphoric acid excludes the assumption of a tri- or tetra-methylene ring,
but indicates the likelihood of the presence of a penta- or hexa-methylene ring in
camphor (J. pr. Ch. [2] 45, 475 ; A. 292, 125).
ACTION OF HEAT, LIGHT, AND ELECTRICITY UPON
CARBON COMPOUNDS
I. ACTION OF HEAT
Substances which react most energetically upon each other do not
do so at very low temperatures (Raoul Pictet, Arch. d. Scienc. phys. et
nat., Geneva, 1893), even when subjected to the greatest pressure, and
when their molecules are in most intimate contact. A definite tem-
perature is essential for the occurrence of chemical action. The
energy of a reaction, the time within which it proceeds, is largely
dependent on the temperature of the reacting substances, therefore
the determination of the most favourable temperature for the
reaction is important. It must be remembered that the heat
developed in chemical changes frequently increases the initial reaction-
temperature rapidly to the point of decomposition. In such cases
the violence of the reaction must be moderated by cooling or by the
62 ORGANIC CHEMISTRY
use of indifferent diluents, in which the substances acting upon each
other must be dissolved before the reaction occurs.
The action of chlorine upon toluene (q.v.) or upon methyl toluene shows par-
ticularly well how much the kind and nature of the action is dependent upon the
temperature. At the ordinary temperature the chlorine substitutes the hydrogen
of the phenyl residue, whilst at the boiling temperature it is the hydrogen of the
methyl group which is replaced :
CI /- - > C.H4C1.CHS
C^CHa-^^ Quinary temp.
\ - >- C.H..CHaCl.
At H3°-iii*
Numerous analogous observations are known.
In general, carbon compounds are much less stable undei the
influence of heat than the inorganic bodies. When the qualitative
examination of organic bodies was discussed, mention was made of
the fact that many carbon compounds were decomposed under tbe
influence of heat with the separation of carbon.
Other compounds, when heated at the ordinary temperature, re-
arrange themselves without alteration of their molecular magnitude,
whilst some polymerize. Compounds, volatilizing undecomposed at
ordinary pressure, may become decomposed when their vapours are
conducted through tubes heated to redness, or by contact with metallic
wires rendered incandescent by the electric current (C. 1901, 11, 1042) ;
as a rule, new bodies are then formed accompanied by partial
carbonization. The splitting-off of hydrogen, the halogens, haloid
acids, water, and ammonia leads to a more intimate union of the
already combined carbon atoms, and carbon atoms which previously
were not united with one another not infrequently combine to yield
carbocyclic and heterocyclic bodies : pyro-condensations result (B. 11,
1214).
In the special part of this volume, such results from heat action
will be so frequently encountered that it becomes unnecessary to
present examples at this time (comp. ethyl alcohol and chloroform).
It may suffice to mention coal tar, which contains the liquid bodies
formed by the decomposition of coal under the influence of heat.
This material is of the greatest importance both in the development
of scientific, theoretical organic chemistry, as well as for technical
chemistry (coal-tar industry). It is mainly composed of car bo- and
heterocyclic compounds, stable under the influence of heat :
Benzene. Naphthalene. Anthracene, Phenanthrene.
C4H4S CBH5N C,H7N C18H9N
Jhiophene. Pyridine. Quinoline and Isoquinoline. Acridine.
2. ACTION OF LIGHT
Light exerts a great influence upon carbon compounds. The well-
known reactions of this kind in the field of inorganic chemistry have
corresponding cases in the province of organic chemistry.
Light is able to bring about the decomposition, the rearrangement, and the
synthesis of carbon bodies. Just as the haloid salts of silver are decomposed with
separation of silver, so, too, the alkyl iodides separate iodine under the influence
ACTION OF LIGHT 63
of light. Hence their colourless solutions gradually become yellow and finally
dark brown in colour. Ethyl mercuric iodide breaks down into mercurous iodide
and butane. Experience shows that many other carbon derivatives decompose
more or less rapidly when they are exposed to sunlight, hence they must be
preserved in the dark or in vessels of brown coloured glass, which absorbs the
chemically active rays of sunlight. It is technically important that an organic
dye should resist the influence of light ; most of them are not fast colours, but
are bleached by light.
Of the decomposition-reactions produced by sunlight mention may be made of
the change undergone by succinic acid, when mixed with uranium oxide ; it loses
carbon dioxide, and propionic acid results (A. 133, 253) :
COaH.CHa.CHa.COaH=COa+CH3.CH2.C02H.
Solutions of tartaric acid and citric acid, when mixed with uranium oxide,
are similarly decomposed by sunlight (A. 278, 373).
An aqueous solution of acetone is partially hydrolized by sunlight into acetic
acid and methane (B. 36, 1582).
Mercury oxalate is decomposed by light into COa and mercury ; if ammonium
ride be present, calomel is formed. A similar reaction is the following : —
2HgCla +Ca04(NH<) a =HgaCla +2COa +2NHfCl.
Sunlight often acts as a polymerizing agent. Solid anthracene, in the form
of a vapour or solution is polymerized by sunlight or the light of a carbon or
mercury arc lamp into dianthracene, a change which is completely reversed in the
dark (Z. phys. Ch. 53, 385). For similar cases of phototropy see B. 37, 2236.
Finely divided cinnamic acid changes in sunlight to the dimeric modification
truxillic acid, which returns to the simpler form under the influence of heat ;
cinnamylidene malonic acid behaves in the same way (Z. phys. Ch. 48, 345).
For the polymerization of benzaldehyde see B. 36, 1573.
Geometric isomers (alloisomers or stereoisomers) are frequently changed into
their stable forms by sunlight ; for instance, maleic acid into fumaric acid (B. 36,
4267), allocinnamic acid into cinnamic acid ; anti-oximes into syw-oximes (B. 36,
4268 ; 37, 1 80).
The combination of carbon monoxide and chlorine, forming carbonyl chloride
or phosgene (Davy) is analogous to the complete union of hydrogen and chlorine,
forming hydrogen chloride, and of benzene and chlorine or bromine to form
hexa-chloro- or hexabromo-benzene, in sunlight :
H,-f-Cla=2HCl; CO+Cla=:COCla; CeHe+3Cla=C.H,Cl6.
The action of chlorine upon methane (p. 72), formaldehyde (B. 29, R. 88), and
other carbon derivatives which can be substituted, is much influenced by sunlight.
The experiments conducted by Klinger show that the chemical action of sun-
light is susceptible of more extended application than it has yet found, and that
compounds can be produced by it, which could only be prepared in the ordinary
chemical way by most powerful or highly specialized means. He found that
ethereal solutions of benzoquinone, benzil, and phenanthraquinone are reduced,
with the formation of aldehyde* Further, that acetaldehyde, isovaleraldehyde,
and benzaldehyde unite, under the influence of sunlight, with phenanthraquinone,
in accordance with the equation (A. 249, 137) :
C,H4.CO C,H4.CO.COR
I +RCHO = | ||
C6H4.CO C,H4.COH.
Isovaleraldehyde and benzaldehyde also unite directly with benzoquinone,
but in a still more striking manner, in that a nucleus-synthesis (p. 75) results.
With benzaldehyde the reaction proceeds as follows : —
C8H,Oa+C6H6.COH=C8H6.CO.C8H3(OH)a
Benzo- Benz- Dihydroxybenzophenone — isomeric with the
quinone. aldehyde. expected Monobenzoyl Hydroquinone.
Sunlight reduces a carbonyl group in alcoholic solution, and at the same time
the alcohol becomes oxidized to aldehyde, as for instance, benzophenone and
acetophenone yield the corresponding pinacones ; quinone oxidizes glycerol to
glycerose, erythritol to erythrose, mannitol to mannitose, dulcitol to dulcitose,
clextrpse to dextrosone, whilst in each case the quinone changes to quinhydrone.
64
ORGANIC CHEMISTRY
Aromatic nitro-bodies readily give up their oxygen to alcoholic or aldchydic
groups under the influence of sunlight : nitrobenzene and alcohol give aniline and
qumaldine ; nitrobenzene and benzaldehyde yield a mixture of benzoic acid,
nitrosobenzene, /?-phenylhydroxylamine and products of further interaction;
o-nitrobenzaldehyde changes completely into o-nitrosobenzoic acid ; o-nitro-
benzal aniline gives o-nitrosobenzanilide, and so on (Ciamician and Silber, B. 37,
3425 ; B. 38, 1176, 3813).
o-Nitrobenzylidene acetophenone in ethereal solution is changed by sunlight
to indigo and benzoic acid (Engler and Dorant, B. 28, 2497) :
j[i]COCH=--CH.C,H6 C6H4|[i] C(\
2CaH4
*
I [2] NO,
[2]NH
CO [i]
NH[2]
CflH4+2C6H5C02H
The study of these reactions is specially important in the interpretation of the
chemical changes occurring in plants.
3. ACTION OF ELECTRICITY
Some of the- reactions induced by the aid of electricity possess
great value for synthetic organic chemistry. The only method
which will cause the union of free hydrogen with free carbon, consists
in the action of the electric discharge upon the two elements. Berthelot
ttUCH
FIG. 10.
showed that carbon and hydrogen combined to form acetylene on the
passage of the electric spark between carbon points in an atmosphere
of hydrogen : 2C+H2=CH^CH. Small quantities of methane CH4,
and ethane C2H0 were also present, as was found later (C. 1901, II.
576) . Fig. 10 represents the apparatus in which this important synthesis
was carried out (A. china, phys. ; [4] 13, 143 ; B. 23, 1638 ; C. 1897,
I. 24).
Acetylene and nitrogen (A. 150, 60) as well as cyanogen and hydrogen, unite
to yield hydrocyanic acid under the influence of electric discharges (C. r. 76, 1132) ;
and carbon monoxide and hydrogen form methane (Brodie, A. 169, 270).
CH CN
III +Na-=2HNC; I +H.=2HNC; CO+3Ha=CH4+H«O.
CH CN
An important application of the heat derived from electricity is the prepara-
tion of the carbides in the electric furnace (Moissan) * where temperatures of
about 3000° can easily be reached. Calcium and aluminium carbides are of the
* Der elektrische Of en, H. Moissan, translated into German by Zettel, 1900.
COMBINATION OF CARBON WITH OTHER ELEMENTS 65
greatest significance to organic chemistry, because water liberates from them
acetylene and methane respectively (comp. p. 67).
Other thermal reactions can also be effected, such as passing the vapours of
carbon compounds over a metallic spiral heated to incandescence by an electric
current (C. 1901, II. 1042 ; see also B. 18, 3350).
Kolbe decomposed the aqueous solutions of the potassium salts of monobasic
carboxylic acids, especially potassium acetate, by the electric current, and thus
prepared dimethyl or ethane. The following equation represents the electrolysis
of potassium acetate : —
KOHH
CH3C02K+HO;H = CH3+C02+KOH+H
Kekule applied this reaction to the saturated dicarboxylic acids, e.g. succinic
acid, and later he and A arland extended it to the unsaturated dicarboxylic acids :
fumaric acid, maleic acid, mesaconic acid, citraconic acid, and itaconic acid (A. 131,
79 ; J. pr. Ch. [2] 6, 256 ; 7, 142 ; comp. C. 1900, I. 1057 ; II. 171), with the pro-
duction of the unsaturated hydrocarbons, ethylene, acetylene, and allylene. Kolbe
and Moore obtained ethylene dicyanide from cyanacetic acid (B. 4, 519).
Crum Brown and /. Walker included the potassium salts of the acid esters of the
dicarboxylic acids among these reactions, and obtained the neutral esters of
dibasic acids, e.g. potassium ethyl malonate yielded succinic diethyl ester (A. 261,
107 ; B. 24, R. 36 ; A. 274, 41 ; B. 26, R. 369, 380). In the electrolysis of an
alcoholic solution of sodium malonic diethyl ester Mulliken obtained ethane
tetracarboxylic ester (B. 28, R. 450).
V. Miller and Hans Hofer showed that by electrolysis of potassium acetate
and potassium ethyl succinate, butyric ester is formed (B. 28, 2429). Mulliken
obtained ethane tetracarboxylic ester by electrolysis of an alcoholic solution of
sodium malonic diethyl ester (B. 28, R. 450).
Hamonet obtained the diamyl ether of butane-diol by the electrolysis of the
amyl ether of potassium /?-hydroxypropionate (C. 1901, I. 613). From the salts
of ketocarboxylic acids, either alone or mixed with acetates, Hofer obtained by
electrolysis ketones and diketones : pyroracemic acid yields diacetyl ; laevulinic
acid gives octane-2,7-dione, pyroracemic acid and acetic acid yield acetone
(B. 33, 650).
Hydrogen, generated by electrolysis, is a valuable means for reducing organic
substances, as its action can be varied according to the liquid, current, voltage,
cathode material, etc., employed for the particular requirements of the experiment.
Aromatic nitro-bodies can be changed into their various reduction products —
jS-phenylhydroxylamines, aminophenol, azoxy- azo- or hydrazo-bodies, or into
anilines (B. 28, 2349 ; 2tt, 1390 ; 38, 3076). Many substances which are difficult
to reduce by chemical methods, such as carboxyl groups in ketones, carboxylic
acids and their esters, lactams, dicarboxylic acid imides, and others, can easily
be reduced to CHOH or CH2 groups in sulphuric acid solutions with cathodes
possessing a high " supertension " (Cd, Hg, Pb) (Tafel, B. 33, 2209 ; 37, 3187,
etc. ; A. 348, 199).
THE DIRECT COMBINATION OF CARBON WITH OTHER
ELEMENTS
Before dealing with the systematic classification of the carbon
compounds, some remarks may be made, by way of introduction, on
the direct combination of carbon with other elements. Carbon and
its various allotropic modifications are described in text-books on
inorganic chemistry, but its affinity to other elements may well be
discussed here also, since from the substances formed the innumerable
compounds in organic chemistry are derived.
VOL. I. F
66 ORGANIC CHEMISTRY
With one exception the combining power of carbon becomes
operative only at high temperatures. In the finely-divided form of
soot, carbon will combine with fluorine, to form tetrafluoromethane
or carbon tetrafluoride
C-{-2Fa=CF4.
Combination with hydrogen or chlorine can only be brought about
under the influence of the electric arc, when carbon and hydrogen unite
to form acetylene, the most reactive of all hydrocarbons, together with
a little methane (p. 64) :
2C+Ha=CaHs, C+2Ha=CH4;
and chlorine and carbon combine to form hexachlorethane and per-
chlorobenzene :
2C+3Cla=CaCl8; 6C+3C12=C,C1,.
Oxygen unites with carbon, producing carbon monoxide and carbon
dioxide or carbonic acid gas :
C4-O=CO; C+Oa=COa.
Which of these two substances is formed depends on the temperature of re-
action. At very high temperatures only carbon monoxide is formed, the dioxide
being produced below this. The affinity of carbon for oxygen is so great that at
sufficiently high temperatures the most stable oxides give up their oxygen, so that
carbon becomes the most important reducing agent for technical purposes.
Sulphur combines with carbon at high temperatures in only one
proportion forming carbon disulphide — the sulphur analogue of the
anhydride of carbonic acid :
c+sa=csa.
Carbon, nitrogen, and hydrogen combine together when a mixture
of nitrogen and hydrogen is passed between carbon poles of an electric
arc, forming hydrocyanic acid, a reaction which possibly depends on
the primary formation of acetylene :
C+N+H=HNC.
or 2C+ 2H=C,Ha and CaH1+Na=2HNC.
Similarly, carbon, nitrogen, and potassium or sodium, combine at
high temperatures to form potassium or sodium cyanide. This re-
action may also depend on the primary formation of potassium or
sodium acetyUde, followed by subsequent union with nitrogen. Or
a metallic nitride may first be formed which then combines with carbon
to produce the cyanide.
At very high temperatures carbon exhibits the capacity of combining
directly with many elements of a metallic character to form carbides.
Even in the early days the formation of iron carbide was proved to
take place by the action of carbon on molten iron.
However, pure iron carbide is not known, but it appears that carbon combines
with iron m various proportions. This is supported by the generation of a
mixture 01 hydrocarbons when such a specimen of iron is dissolved in acids.
Carbon unites with the metals of the alkaline earths, calcium,
strontium, and barium, in only one proportion. Such a carbide
COMBINATION OF CARBON WITH OTHER ELEMENTS 67
can be considered as being a metal-acetylene compound, which
generates the gas on contact with water. It is prepared by the
reduction of the oxide of the metal by carbon in the electric furnace :
2C+Ca(Sr, Ba)=C2Ca(Sr, Ba).
Aluminium carbide, similarly prepared, gives off methane in contact
with water :
3C+4A1=C3A14.
Beryllium carbide also yields methane ; manganese carbide generates equal
volumes of methane and hydrogen ; the carbides of cerium, lanthanum, yttrium,
samarium, C2Me, give acetylene and methane; uranium carbide, C3U2 yields
methane, hydrogen, and ethylene ; whilst the last-named carbides also yield
considerable quantities of fluid and solid hydrocarbons (C. R. 122, 1462, etc.).
Whilst the carbides of the enumerated metals give off hydrocarbons when
treated with acids or water, the carbides of boron, silicon, titanium, zirconium,
vanadium, tungsten and chromium are extraordinarily stable and unusually hard ;
so much so that silicon carbide is employed, under the name of carborundum, in
boring and polishing. The last three carbides are so far useless in the building
up of carbon compounds.
The most important substances which have been formed by the
direct union of carbon with other elements are :
Acetylene C2Ha
Calcium Carbide C2Ca
Methane CH4
Aluminium Carbide C3A14
Carbon Monoxide CO
Carbon Dioxide COa
Carbon Disulphide . . . . . CS2
Hydrocyanic Acid HNC
Potassium Cyanide KNC.
These bodies are examples of widely different classes of organic com-
pounds ; methane and aluminium carbide are found at the head of the
paraffin or acyclic saturated hydrocarbons, whilst acetylene and calcium
carbide occupy a similar position among the unsaturated acyclic
hydrocarbons possessing a triple bond between two carbon atoms.
Carbon monoxide, hydrocyanic acid and potassium cyanide belong to
the formic acid group of bodies which take the lead among the paraffin
monocarboxylic acids of the acetic acid series ; carbon dioxide and
disulphide are among the carbonic acid groups which are the first
of the paraffin dicarboxylic acids.
Of all these simple compounds of carbon, the most important is
carbon dioxide, which forms the basis for the formation of the carbo-
hydrates and fats during the process of assimilation in the vegetable
organism ; and also of the proteins when nitrogen is taken up.
Since chemists have not yet succeeded in imitating in the labora-
tory the synthetic methods of plants, a large and increasing number of
methods have been provided for linking together simple organic
molecules for the construction of substances of complicated composi-
tion. These methods (see Synthetic Methods, Ring Formation, p. 75)
depend partly on double decomposition, similar to the interaction of
inorganic salts, but mainly on the property of one " unsaturated "
molecule (p. 23) to unite with another ; on reactions brought about
by the agency of metals, especially Na, Mg, Al, Zn; Cu, or suitable
68 ORGANIC CHEMISTRY
compounds of them ; on the influence of acids ; and finally on rise of
temperature, on sunlight or on electricity (pp. 61-65).
CLASSIFICATION OF THE CARBON COMPOUNDS.
The chemical union of the carbon atoms and the resulting character
of the groups is the basis of the division of the carbon compounds into
two principal classes: the fatty or aliphatic substances (from a\fuf>ap,
fat) — the chain or acyclic carbon derivatives or the methane derivatives,
and the cyclic compounds of carbon.
The name of the first class is borrowed from the fats and fatty acids
comprising it, which were the first derivatives to be studied accurately.
They may be termed the marsh gas or methane derivatives, inasmuch
as they all can be derived ultimately from methane, CH4. They are
further classified into saturated and unsaturated compounds. In the
first of these, called also limit compounds or paraffins, the directly
united quadrivalent carbon atoms are linked to each other by a single
bond, so that the number of affinities still remaining to be satisfied
in a chain of n carbon atoms is 2n-\-2 (p. 23). Their general formula
is, therefore, expressed in the form CnX2w+2> where X represents the
affinities of the elements or groups directly combined with carbon.
The unsaturated compounds result from the saturated by the loss of
an even number of affinities in union with carbon. According to the
number of affinities yet capable of saturation, the series are distin-
guished as CnX2rt, CnX2^_2, etc.
The methane derivatives contain open carbon chains, the cyclic
derivatives contain closed carbon chains, or rings. When carbon atoms
alone constitute the ring, the resulting bodies are designated carbo-
cyclic compounds.
Especially important among these cyclic compounds, are those in
which the ring contains six carbon atoms with six free valencies. From
these are derived substances which Kekule named the aromatic com-
pounds or benzene derivatives.
The importance of this group has gained for it a special position in
the chemistry of carbon derivatives. Compared with the aliphatic
compounds, they show such great differences in chemical behaviour
that they were formerly regarded as a second and distinct class of
organic bodies.
With the advances in organic chemistry, numerous compounds were
being constantly discovered which contained carbon atoms united in
a closed ring, but which approached the fatty bodies more closely
than the aromatic derivatives in chemical behaviour. In the so-called
hydroaromatic compounds the more pairs of hydrogen atoms which are
attached to the benzene nucleus in them, the nearer they resemble, in
chemical character, the aliphatic derivatives. Even more closely allied
to the latter are those substances which contain a ring consisting of
three, four, or five carbon atoms —
the trimethylene derivatives,
teiramethylene derivatives,
pentamethylene derivatives.
HYDROCARBONS 69
These constitute the passage from the aliphatic bodies to the hydro-
aromatic compounds, with which the aromatic derivatives are so closely
connected.
There are many carbon compounds containing " rings," in the
formation of which not only carbon atoms, but also oxygen, sulphur,
and nitrogen atoms take part.
Such bodies have been termed heterocyclic compounds (from erepos,
foreign). These derivatives will mainly be discussed at the conclusion
of the remarks on the open chain bodies, from which they are derived
by loss of water, hydrogen sulphide, or ammonia, and into which they
can again be changed. A large class of heterocyclic bodies — more
especially of the thiophene, fufurane, and pyrrole groups, the parent
substances of the plant alkaloids : pyridine, quinoline, isoquinoline,
etc. — like the aromatic bodies, possess a very stable ring. In the case
of many heterocyclic bodies the open chain compounds, from which
they may theoretically be deduced, do not actually exist. Therefore
such heterocyclic compounds will be more conveniently discussed after
the car bo- or isocyclic derivatives. Thus, the chemistry of the com-
pounds of carbon may be divided into : —
I. Fatty Compounds : Aliphatic compounds, methane derivatives,
chain or acyclic carbon derivatives.
II. Carbocyclic Compounds.
III. Heterocyclic Compounds.
I. PATTY COMPOUNDS, ALIPHATIC SUBSTANCES OR METHANE
DERIVATIVES, CHAIN OR ACYCLIC CARBON DERIVATIVES
I. HYDROCARBONS
The hydrocarbons may be regarded as the parent substances from
which all other carbon compounds arise by the replacement of the
hydrogen atoms by different elements or groups.
The fundamental conceptions of the linking of carbon atoms were
put forward in the introduction. We distinguish, therefore, (i) saturated
and (2) unsaturated hydrocarbons. The first contain only singly linked
carbon atoms, whilst the unsaturated contain pairs of carbon atoms
united doubly and trebly. As the first series has attained the limit of
saturation by hydrogen, they are frequently called the limit hydro-
carbons, or, after the first member of the series, marsh gas — the
methane hydrocarbons. They are not very reactive, and are very stable ;
hence their designation as paraffins (from parum affinis).
A. Saturated or Limit Hydrocarbons, Paraffins, Alkanes,* Marsh Gas
or Methane Hydrocarbons, CnH2n+2.
Nomenclature and Isomerism. — In consequence of the equivalence
of the four affinities of carbon (see p. 21), no isomers are possible for
the first three members of the series CnH .>»+ 2 •
CH4 CH3-CH3 CH8-CH2-CHa.
Methane. Ethane. Propane.
* This word is seldom met with. — Tr.
70 ORGANIC CHEMISTRY
Formerly these hydrocarbons were designated the hydrides of uni-
valent radicals — hydrocarbon residues or alkyls : methyl, ethyl,
propyl, etc. Combined with the water residue or hydroxyl, they
yielded the alcohols CJHa^OH. They were at first obtained from
compounds of these radicals with other elements or groups : hence
the names methyl hydride for methane, ethyl hydride for ethane, etc.
The first known and most readily obtained derivatives of the alkyls
CMH2n+1 were their hydroxyl derivatives or the alcohols, e.g. C2H5OH,
ethyl alcohol, and their halogen compounds.
At the suggestion of A . W. Hofmann their names were formed later
by replacing the final syllable " yl " of the alkyls by the final syllable
" ane," so that methane was used for methyl, ethane for ethyl, propane
for propyl, etc., and for the homologous series the name alkanes was
adopted.
Two structural isomers exist for the fourth member, C4H10 :
/CHS
CH,— CH2— CH2— CH8 and CH^-CH,
I Normal Butane. ^CH3
Trimethyl Methane
(Isobutane).
In the name trimethyl methane for isobutane, isomeric with normal
butane, it is indicated that this substance is derived from methane by
the replacement of three hydrogen atoms by three methyl groups.
For the fifth member, pent ane, C5H12, three isomers are possible :
CH,— CH2— CH2— CH2— CH,
Normal Pentane. N3H2 . CH,
Dimethyl Ethyl Methane.
CH3V /CH,
XX Tetramethyl Methane.
CH XCH
The number of theoretically possible isomers now increases rapidly.
Hexane, C6H14, has 6 isomers ; heptane, C7H16, 9 isomers ; octane,
C8H18, 18 isomers ; tridecane, C13H28> 802 isomers. On the calcu-
lation of the number and nature of the isomeric paraffins, see Ch. Z.
1898, I. 395-
Commencing with the fifth member, the names are formed from
the Greek words representing numbers.
The " Geneva Convention " recommends the retention of the ending " ane,"
as first suggested by A. W. Hofmann (J. 1865, 413), for the hydrocarbons CMH2,l+2.
The hydrocarbons with branched carbon chains are considered as being alkyl
substitution products of the normal hydrocarbons already contained in their
formulae, and the carbon atoms of this normal hydrocarbon are numbered. The
numbering is begun with that carbon atom to which the side-chain is adjacent :
(I) (2) (3) (4) (5)
CH8.CH.CH2.CH2.CH3 = [Methyl-2-pentane].
AH.
The carbon atoms of a longer substituting radical are also numbered, and,
£' Jlth tw° numbers : the first» indicating the place where the side-chain is
attached to the normal chain ; and the second, beginning with the carbon atom
which is joined to the main chain as number one,
HYDROCARBONS 71
Should a further alcohol radical attach itself to the middle carbon atom of
the side-chain, then the expressions for the substituting radical are metho-,
etho-, etc., instead of methyl-, ethyl-, etc. :
(i) (2) (3) (4) (5) (6) (7)
CH8.CHa.CH2.CH.CH2.CHa.CH3=[Metho-41-ethyl-4-heptane]4
, i\Cjj cjj L** *f*tf^ 4v>|£
(4*)CH8
The variation in structure of the carbon chain, or carbon nucleus, is
the cause of isomerism in the paraffins. This type of isomerism is
called chain- or nucleus-isomerism (p. 27).
Methods of Formation and Properties of the Paraffins. —
The saturated hydrocarbons are formed in the dry distillation of wood,
peat, bituminous shale, brown coal, coal, particularly the boghead
and cannel coal rich in hydrogen ; hence they are present in illumina-
ting gas and in the light oils of coal-tar. They occur already formed
in petroleum, particularly in that from America, which consists almost
exclusively of them, and contains most members from methane to the
highest. It is difficult to isolate the individual hydrocarbons from
such mixtures. Before advancing to the general methods used in the
preparation of the paraffins — methods by which each separate member
can be easily obtained in pure condition — it will be best to discuss
the two important bodies, methane and ethane.
(i) Methane, CH4, Methyl Hydride, m.p. -184°; b.p.760 - 164° ;
D.=8 (H=i), or 0-555 (air=i) (C.r. 140, 407), is produced in the
decay of organic substances ; it is, therefore, disengaged in swamps
(marsh gas) and mines, in which, mixed with air, it forms fire-damp.
In certain regions, like Baku in the Caucasus and the petroleum
districts of America, it escapes, in great quantities, from the earth.
It is also present, in appreciable amount, in illuminating gas.
The synthesis of methane, the simplest hydrocarbon, from which all
the fatty bodies may be derived, is particularly important. By the
synthesis of a carbon compound is understood its formation from the
elements, or from such carbon derivatives which can be obtained
from the elements. Under proper conditions hydrogen and carbon
may be directly combined, with the production of acetylene CH^CH
(p. 64), together with only a small quantity of methane. The latter
can be obtained (i) from carbon disulphide CS2 (which may also be
made directly from its constituents) if the vapours of this volatile
substance, mixed with hydrogen sulphide gas, be passed over red-hot
copper (Berthelot) :
C+2S=CSa; CS,+2HaS+8Cu=CH4-
Or (2) the carbon disulphide may be converted by chlorine into carbon tetrachloride
CC14, and this reduced, by nascent hydrogen (sodium amalgam and water) :
CSa+ 3Cla=CCl4+S2Cla ; CCl4-f-8H=CH4+4HCl.
(3) Methane is also formed from carbon monoxide and hydrogen, if the
mixture of gases be exposed in an induction tube to the actio'n of electricity
(p. 66), (A. 169, 270), or is led over freshly reduced nickel (C.r. 134, 514) :
aC-fOt=2CO CO+3Ht=CH4-J-HtO.
^2 ORGANIC CHEMISTRY
(4) Aluminium carbide is decomposed, in the cold, by water, forming methane
and aluminium hydroxide (B. 27, R. 620 ; 29, R. 613) :
C3A14 + I2H20=3CH4+2A12(OH)6.
(5, 6) Methyl alcohol, or wood -spirit, CHa.OH, can be converted into methane
by first changing it to methyl iodide, and then reducing the latter with nascent
hydrogen from moist zinc-copper, or with zinc dust in the presence of alcohol
(B. 9, 1810), or with potassium hydride (C. 1902, I. 708) ; or by preparing zinc
methyl, Zn(CH3)2, from methyl iodide, and decomposing it with water:
CH..OH - — > CH3I+2H=CH4+HI
HOHCH
Zinc Methyl.
(7) Instead of using zinc methyl, it is more convenient to decompose an
ether solution of methyl magnesium iodide with water :
CH3MgI+H20=CH4+MgI.OH.
In the laboratory methane is made (8) by heating sodium acetate
with soda-lime, of which the active ingredient is sodium hydroxide.
The addition of the lime is for the purpose of protecting the glass
vessel from the corroding action of the molten sodium hydroxide :
CH3.CO2Na+NaOH=CH4-r-Na2CO,,
Methane is a colourless gas possessing a slightly alliaceous odour.
Its critical temperature is —82°, and its critical pressure 55 atm. At
low temperatures it forms colourless needles. It is slightly soluble in
water, but more readily in alcohol. It burns with a faintly luminous,
yellowish flame, and forms explosive mixtures with air, oxygen, and
chlorine :
CH4+2O2=CO2+2HaO (steam).
I VOl. 2 VOlS. I VOl. 2 VOlS.
It is decomposed into carbon and hydrogen by the continued
passage of the electric spark. When mixed with two volumes of
chlorine it explodes in direct sunlight, with separation of carbon,
CH4+2C11=C+4HC1.
In diffused sunlight chlorine substitution products are produced :
CH4 + C12=HC1+CH3C1 — Monochloromethane or methyl chloride,
CH3C1 +C12=HC1+CH2C12 — Dichloromethane or methylene chloride.
CH2C124-C13=HC1+CHC1S— Trichloromethane or chloroform.
CHC18 +C12=HC1-J-CC14 — Tetrachloromethane or carbon tetrachloride.
Through methyl chloride methane may be converted into methyl
alcohol, ethane, ethyl alcohol, and acetic acid.
Fluorine reacts explosively at —187°.
Ethane, Ethyl Hydride, Dimethyl, Methyl Methane, CH3.CH3,
m.p. -172° (B. 33, 637); b.p.760-84°; D.0 (liquid) = 0-466 (B. 27,
2767> 3305)- This hydrocarbon was discovered in 1848 by Frankland
and Kolbe. It is formed (i) by the addition of hydrogen to the two
unsaturated hydrocarbons, acetylene (p. 87) and ethylene (p. 81), when
the multiple linkage of the carbon atoms is broken down.
HYDROCARBONS 73
Ethane may be obtained from ethyl alcohol by way of (2) ethyl
iodide or (3) of zinc ethyl, just as methane was prepared from methyl
alcohol :
C3H6OH — — > C2H5I +2H =C2
L
Or (4) magnesium ethyl bromide (p. 72, Methane) may be decom-
posed by water ; or (5) mercury ethyl by concentrated sulphuric acid :
C2H5MgBr+H20=C2H«+MgBr.OH
(C2H5)2Hg+H2S04=2C2H5.H+HgS04 (Schorlemmer) .
These last three methods led to the assumption that ethane was
ethyl hydride. The following reactions show how ethane can be formed
from the union of two methyl residues, and hence led to the view that
the hydrocarbon was dimethyl. (6) Sodium is allowed to act on
methyl iodide — the reaction is accelerated by the addition of one drop
of acetonitrile (C. 1901, II. 24) — or (7) zinc methyl may be substituted
for the metal :
2CH3I+2Na=CH3-CH3+2NaI (Wurtz).
2CH3I + (CH8)2Zn=2CH3-CH3+ZnI2.
A more convenient method (8) consists in heating acetic anhydride with barium
peroxide :
2(C2H30)20+BaOa=C2H6 + (C
From a theoretical point of view (9) the electrolysis of a concen-
trated solution of potassium acetate (p. 65) (the method used by Kolbe
(1848) by which he discovered ethane), is of great importance. The
salt breaks down into its two electrochemical constituents — potassium,
its electro-positive ion, appearing at the negative pole and separating
hydrogen from water at that point, and the unstable electronegative
ion radical CH3.C02 — , which immediately decomposes at the positive
pole into — CH3 and CO2. Two methyl groups then unite to dimethyl,
just as two hydrogen atoms combine to form a molecule of that element ;
CH8jC02
CH3JC02
K HO ri Cti3 H
-I-
K IK
= +2CO2+2KOH + |
a CH3 H
Both Kolbe and Frankland believed that ethyl hydride C2H5.H differed from
dimethyl CH3.CH3. Such a difference was not possible in the light of the valence
theory. By converting the hydrocarbon from (C2H6)2Hg and that obtained in
the electrolysis of potassium acetate into the same ethyl chloride Schorlemnier
(1863) proved the identity of ethyl hydride C2H5.H and dimethyl CH8.CH3, thus
confirming a fundamental requirement of the valence theory :
H2SO4
(C2H5)2Hg --- >C2H6.H
electric current Clj
2CH3.C02K - — >CH8.CH3
Ethane is a colourless and odourless gas. Its critical temp3rature
74 ORGANIC CHEMISTRY
equals +34° and its critical pressure is 50*2 atmospheres. It acts like
methane towards solvents.
Ethane can be converted into ethyl alcohol through its monochloro-
substitution product.
Homologues of Methane and Ethane. — In preparing the homo-
logous paraffins, the homologues of ethyl alcohol CwH2n-n«OH and the
saturated fatty acids are employed.
I. Formation from compounds containing a like number of
carbon atoms.
(1) From the unsaturated hydrocarbons by the addition of hydrogen
(see Ethane).
(2) By the reduction of alcohols, ketones, and carboxylic acids.
(a) The alcohol, for example ethyl alcohol, is changed to the chloride,
bromide, or iodide, which is then reduced with nascent hydrogen,
by means of zinc and hydrochloric acid, or sodium amalgam and
alcohol. The iodide may alternatively be treated with aluminium
chloride (B. 27, 2766).
Thus, propane has been prepared from the two propyl iodides C3H7I by zinc
and hydrochloric acid, as well as from isopropyl chloride by sodium-ammonium
(C. 1905, II. 112). Trimethyl methane has been obtained by the action of zinc
and hydrochloric acid on the iodide of tertiary butyl alcohol. Also, by heating
the alkyl iodides with zinc and water in sealed tubes at 120-180°, paraffins are
obtained.
(&) The saturated fatty acids, CnHan-n-COaH, particularly the higher members
of the series, may be converted into the corresponding paraffins by heating them
with concentrated hydriodic acid and red phosphorus to 200-250°
Stearic Acid. ^ Octadecane.
(c) The ketones (q.v.), resulting from the distillation of the calcium salts of
fatty acids, change to paraffins when they are heated with hydriodic acid. It is
more practical first to prepare the keto-chlorides (p. 93) by the action of phos-
phorus pentachloride upon the ketones, and then to reduce them.
The last two reactions especially were applied (B. 15, 1687, 1711 ; 19, 2218) in
the preparation of the normal hydrocarbons from nonane, CHJCHjUCHg, to
tetracosane CH3(CH2)22CH,.
(3) Or, the alcohol is changed by way of the alkyl iodide into a
zinc or mercury alkyl, and the zinc alkyls are then decomposed by
water (see Methane and Ethane), and the mercury alkyls by acids
(see Ethane). Also, the easily prepared magnesium halogen alkyls
may be decomposed by water, thereby liberating the paraffin (C. 1901,
I. 1000).
II. Formation from compounds rich in carbon, with loss of carbon. \
(4) A mixture of the salts of fatty acids (the carboxyl derivatives
of the alkyls) and sodium or potassium hydroxide, or better, soda-
lime, is subjected to dry distillation (see Methane).
When the higher fatty acids are subjected to this treatment the usual products
are the ketones ; hydrocarbons, however, are produced when sodium methoxide
is used in place of soda-lime (B. 22, 2133).
HYDROCARBONS 75
The dibasic acids are similarly decomposed :
/CO2.Na
C,H12< +2NaOH=C,H14-f2Na2CO8.
xCOa.Na
III. Methods of Formation, consisting in the union of alkyls, previously
not directly combined, with one another.
(5) Method of Wurtz : this consists in the action of sodium (or
reduced silver or copper) on the bromides or iodides of the alcohol
radicals in ethereal solution (see Ethane). Thus with sodium :
C2H6I yields C2H6.C2H5 Diethyl or normal Butane.
CH3CH2CH2I „ C3H7.C3H7 Di-normal-propyl or normal Hexane.
CH3CH«CH2CH2I „ C4H9.C4H9 Di-normal-butyl or normal Octane.
The addition of one or two drops of acetonitrile accelerates the reaction
(C. 1901, II. 24). This reaction proceeds especially easily with normal alkyl
iodides of high molecular weights. Thus, Hell and Hagele, by fusing myricyl
iodide with sodium, obtained hexacontane, C60HJ22, a compound having by far
the longest normal carbon chain known up to the present time (B. 22, 502). By
employing a mixture of the iodides of two primary alcohols, hydrocarbons result
from the union of the differing radicals. The iodides of optically active (p. 30)
alcohols, e.g., optically active amyl iodide, yield optically active paraffins (B. 27,
R. 852) . Magnesium acts similarly to sodium on the iodides of the higher alcoholic
radicals (C. 1901, 1. 999 ; B. 36, 3083), for example : tertiary butyl bromide and
magnesium give hexamethyl ethane (CH3)3C.C(CH3)3, which is also formed by
the interaction of pentamethyl ethyl bromide and methyl magnesium bromide
(C. 1906, II. 748) :
C(CH3)8.C(CH3)2Br+CH3MgBr=(CH3)3C.C(CH3)8+MgBr2.
(6) Action of zinc alkyls on alkylogens (see Ethane) and ketone chlorides :
thus, tertiary butyl iodide and zinc ethyl give trimethyl ethyl methane (B. 32,
1445 ; 33, 1905) ; also acetone chloride or J3-dichloropropane is changed by zinc
methyl into tetramethyl methane :
Acetone Chloride.
(7) By the electrolysis of the alkali salts of fatty acids (see. Ethane). Alcohols
may occur as subsidiary products : methyl alcohol from potassium, acetate ;
ethyl alcohol from sodium propionate. Also unsaturated hydrocarbons, as
isobutylene, may be produced from trimethyl acetic acid.
Synthetic Methods. — The last group of reactions comprises
synthetic methods for the building up of hydrocarbons. In the for-
mation of methane from carbon disulphide and hydrogen sulphide
it was explained what in general was understood by the synthesis
of a carbon compound. Those reactions in which carbon atoms, not
before combined with one another, become united, claim particular
importance in the synthesis of the compounds of carbon (Lieben, A.
146, 200). Most of the carbon derivatives are due in the first place
to the combining power of the carbon atoms among themselves. Such
reactions are the synthetic methods of organic chemistry in the more
restricted sense. In the future we shall designate them nucleus-
syntheses. They genetically bind together the members of an homo-
logous series, and the homologous series among themselves, and the
open carbon chains with closed chains, or rings.
The synthesis of a carbon compound from derivatives of carbon of
76
ORGANIC CHEMISTRY
known structure is one of the most important means employed for the
recognition of its structure or constitution.
Properties oj the Paraffins. — The lowest members of the series up
to butane and tetramethyl methane are gases at the ordinary tem-
perature. The middle members are colourless liquids, with a faint
but characteristic odour. The higher representatives, beginning with
hexadecane, C16H34, m.p. 18°, are crystalline solids. The highest
members are only volatile without decomposition under reduced pressure.
The boiling points rise with the molecular weights ; the difference for
CH2 is at first 30°, and with the higher members it varies from 25° to 13°.
The boiling points of propane, of the two butanes, the three pentanes,
and the five known hexanes are given in the following table. All the
theoretically possible isomers are known :
Structural Formula.
CH3.CH2.CH3
C3H8
C4H]0
C6H12
Propane
Normal Butane
Trimethyl Methane
Normal Pentane
Dimethyl Ethyl Methane
Tetramethyl Methane
Normal Hexane
Methyl Diethyl Methane
Dimethyl Propyl Methane
Di-isopropyl
Trimethyl Ethyl Methane
CH3.CH2.CH2.CH3
CH3.CH(CH3)2
CH3.[CH2]3.CH3
CH3CH2.CH(CH3)2
C(CH3)4
CH3[CH2]4CH3
CH3CH(C2H5)2
CH3CH2.CH2CH(CH3)0 +62°
(CH3)2CH.CH(CH3)2 " +58°
CH3CH2.C(CH3)3
B.p. at. 760 ro.m.
-45° (B. 27, 3306;
C. 1905, IT. 112).
+ i° (B. 27, 2768).
+ 30°
+ 9°
o
+ 64°
+49° (B. 32, 1449).
It is evident from this table that among isomers those with
normal structure (p. 27) have the highest boiling points : generally
the accumulation of methyl groups in the molecule lowers the boiling
points. The same regularity will be again encountered in other
homologous series. The subjoined table contains the melting points,
boiling points, and the specific gravities of the known normal
paraffins :
M.P.
C,H1fi
' B.P. Sp. Gr.
98*4° 0*7006 i
0
Octane .
^7x-M6 ...
C8H18 . jj
I2VS° 0'7l88 I
o°(
Nonane . . ,
Decane . . ,
C,H,o -51°
C10H2, 32°
••*j D ^^ ^AO-U i
Mg'-b0 0-7330 (
17^ O'74. ^6 i
°o)
Undecane
Dodecane
Tridecane
Tetradecane .
Pentadecane
Hexadecane .
Heptadecane
Octadecane .
Nonadecane .
Kicosane .
^1 OiJ-22 J^
CnH14 -26-5° J
C12H26 -12° |(
C13H28 -6-2°
C14H30 +5-5°
C15H32 +10° |
C16H34 +18° «
C,7H36 +22-5°
C18H38 +28°
C)9H40 +32°
ConH.,o 4-^6-7°
/ J /T-D^I
194-5° 0-7745'
214° 0-773
234 0-775
252-5° 0-775
270-5° 0-775
287-5° 0-775
303° 0-776
317° 0-776
33° 0-777
2Os O"777
( at their
mT-|
Heneicosane .
Docosane
Tricosane, .
Tetracosane .
Heptacosane .
Hentriacontane
Dotriacontane
Pentatriacontan<
Dimyricyl . .
1
v^20Ai42 ~a'J / &
C2]H44 +40-4° 1
C22H48 +44'4° &
C23H48 +47-7° g(
C24H50 +51-1° a
^27^58 +59'5° %
C31H64 +68-1° fe
C32H66 +70.0° 5
C35H72 +74*7°
C60H122 +102°
J w ///
215° 0-778
224-5° 0-778
234° 0-778
243° 0-778
27° 0'779
302 0-780
310° 0-781
331° 0-781 i
>•»?•
HYDROCARBONS 77
n-Heptane is formed during the distillation of the resin of Pinus Sabiniana
and Pinus Jeffreyi (C. 1901, I. 114^). Methyl eihyl propyl methane, one of the
isomers of n-heptane, is the simplest hydrocarbon containing an asymmetric
C-atom (see p. 29). Its dextro-rotatory form, b.p. 91°, and 'a!D=+9-50, is pre-
pared by the action of sodium on ethyl iodide (B. 37, 1046).
Of the isomers of n-octane, hexameihyi ethane (CH3)3C.C(CH3)3, m.p. 104°,
b.p. 107°, should be mentioned on account of its high vapour pressure, and
similarity to perchlorethane (p. 95) ; it results from the reaction of pentamethyl
ethyl bromide and methyl magnesium bromide (C. 1906, II. 748).
Heptacosane and hentriacontane have been found in American tobacco
(C. 1901, IT. 395).
The saturated hydrocarbons are insoluble in water, whilst the lower and
intermediate members are readily soluble in alcohol and ether. The solubulity
in these last two solvents falls with increasing molecular weight : dimyricyl,
C60H(22> m.p. 102°, is scarcely soluble in either of them.
The specific gravities of the liquid and solid hydrocarbons increase with their
molecular weights, but are always less than that of water. It is remarkable that
in the case of the higher members the specific gravities at the point of fusion are
almost the same. They rise from 0773 for dodecane C,2H26, to but 0781 for
pentatriacontane, C35H72 ; consequently the molecular volumes are nearly
proportional to the molecular weights (B. 15, 1719 ; A. 223, 268).
The paraffins are not absorbed by bromine in the cold or sulphuric
acid, being in this way readily distinguished and separated from the
unsaturated hydrocarbons. They are very stable, and, in con-
sequence, react with difficulty. Fuming nitric acid and even chromic
acid are without much effect upon them in the cold ; when
heated, however, they generally are oxidized directly to carbon
dioxide and water. Recently, n-hexane and n-octane have been
nitrated by heating them with dilute nitric acid. The isomers are
more easily attacked than are the n-paraffins (see nitro-derivatives of
the paraffins). When acted on by chlorine or bromine they yield
substitution products.
By means of the latter the paraffins can easily be converted, as
observed under methane and ethane, into other derivatives.
When nitrating and chlorinating the paraffins and the paraffin groups in
carbon compounds, the general rule holds good that in most cases the tertiary
hydrogen atom is easier to replace than the secondary, and the secondary than
the primary (B. 32, 1443).
Technical Preparation of the Saturated Hydrocarbons. — The hydro-
carbons, readily obtainable on a commercial scale, are employed in
enormous quantities for illuminating and heating purposes, are also
used as solvents for fats, oils, and resins, as lubricants for machinery,
and as salves.
The great abundance of mineral oil, petroleum, rock-oil, naphtha, is
of the utmost importance to chemical industry. The oil is very widely
distributed, but only occurs in certain districts in sufficiently large
quantities to be usefully worked. It is especially abundant in Pennsyl-
vania and Canada, although it is also found in the Crimea along the
Black Sea, and at Baku on the shore of the Caspian, as well as in
Hungary, Galicia, Roumania, and the Argentine Republic. Its
occurrence in Germany, in Hanover, and in Alsace is limited. Since
the year 1859 efforts have been put forth to work oil wells which have
been known for many years, and also to make new borings. (See
Hofer . Das Erdol und seine Verwandten, 1906.)
78 ORGANIC CHEMISTRY
The following data give some idea of the vast quantities in which this product
is handled ; in 1904 the world's production of crude naphtha was about 28*6
million tons, of which America contributed 15-0 million tons, Russia io'6, Dutch
Indies i'o, etc. Since 1901 the production in Russia has fallen, whilst in America
and most other countries it has risen.
In a crude state it is a thick, oily liquid, of brownish colour, which
appears green by reflected light. Its more volatile constituents are
lost upon exposure to the air ; it then thickens and eventually passes
into a.sphaltum. The greatest differences prevail in the various kinds
of petroleum. It is very probable that petroleum has been produced
by the decomposition of the fatty constituents of fossil animals. This
took place under the influence of great pressure and the heat of the
.earth. The distillation of fish blubber under pressure has yielded
products very similar to the American petroleum (Engler, B. 26, 1449 ;
30, 2908 ; 33, 7 ; Ochsenius, B. 24, R. 594).
Mendelejeff first suggested that it was possible for petroleum to be
formed by the action of water on the metallic carbides in the interior
of the earth, and Moissan subsequently came to the same conclusion
during his investigations on the carbides (B. 29, R. 614).
Apart from geological evidence the following facts contradict this
view and favour an organic origin for petroleum : (i) a small nitrogen
content (pyridine bases) in most specimens of petroleum ; (2) the
optical activity of the higher fractions, which according to present
knowledge could not be formed by such a synthesis, as this would
lead to the formation of racemic (inactive) bodies only (p. 56, Ch. Z.
1096, 711).
The constituents of American petroleum possessing a low boiling
point, consist almost entirely of saturated hydrocarbons, both normal
paraffins and those of the general formulae R2.CH.CH.R2, CHR3, and
CR4 (B. 32, 1445 ; 33, 1905). Yet small quantities of some of the
benzene hydrocarbons (cumene and mesitylene) are present. The
crude oil has a specific gravity of o*8-O'92, and distils from 30° to 360° and
higher. Various products, of technical value, have been obtained from
it by fractional distillation : Petroleum spirit, sp. gr. o* 665-0* 67, dis-
tilling about 50-60°, consists of pentane and hexane ; petroleum
benzine, sp. gr. o*68-o*72 (not to be confounded with the benzene of
coal tar), distils at 70-90°, and is composed of hexane and heptane ;
ligroine, boiling from 90° to 120°, consists principally of heptane and
octane ; refined petroleum, called also kerosene, boils from 150° to 300°,
sp. gr. O'7§-0'82. (For the apparatus of Engler and Abel intended to
determine the flash point of petroleum, see Eisner : Die Praxis des
Chemikers, [1893] 399, 401 ; B. 29, R. 553.) The portions boiling
at high temperatures are applied as lubricants ; small amounts of
vaseline and paraffins (see below) are obtained from them.
Caucasian petroleum (from Baku) has a higher specific gravity than the
American ; it contains far less of the light volatile constituents, and distils at
about 150°. Upwards of 10 per cent, of benzene hydrocarbons (C6H8 to cymene
cioHi4) as well as less saturated hydrocarbons, CnH2n_8, etc., may be extracted
by shaking it with concentrated sulphuric acid (B. 19, R. 672). These latter are
also present in the German oils (Naphthenes, B. 20, 595). That portion of the
Caucasian petroleum insoluble in sulphuric acid consists almost exclusively of
CnH,n hydrocarbons, the naphthenes, which belong to the cycloparaffins (p. 8o)f
OLEFINES 79
and are probably chiefly cyclopentanes, mixed, perhaps, with aromatic hydrides ;
hexahydroxylene=octonaphthene, hexahydromesitylene=non-naphthene (B. 16,
1873 ; 18, R. 186 ; 20, 1850, R. 570). From its composition, Galician petroleum
occupies a position intermediate between the American and that from Baku
(A. 220, 1 88).
German petroleum also contains benzene hydrocarbons (extractable by
sulphuric acid), but consists chiefly of the saturated hydrocarbons and naphthenes
(Kramer, B. 20, 595). The so-called petrolic acids are present in all varieties of
petroleum, particularly that from Russia (Beilstein, Hdb. d. org. Ch., III. Ed.
522, C. 1897, I. 1153).
Products similar to those occurring in mineral oil are yielded by the tars
resulting from the dry distillation of brown-coal (from the province of Saxony),
and of the bituminous shale (in Scotland and the Gewerkschaft Messel, Darmstadt,
in Hesse). These tars contain appreciably greater quantities of unsaturated
hydrocarbons associated with the naphthenes and paraffins, as well as the aromatic
hydrocarbons present in the tar from bituminous shales (Heusler, B. 28, 488 ; 30,
2743 ; Z. anorg. Ch. 1896, 319). Large quantities of solid paraffins are also present
in these tar oils.
By solid paraffin is ordinarily understood the high-boiling solid
hydrocarbons (above 300°) obtained by the distillation of the tar
of wood, peat, lignite, and bituminous shales. They were discovered
by Reichenbach (1830) in the tar from the beech- wood, and, in nature
occur more abundantly in the petroleum from Baku than in that from
America. In the free state they constitute the class of mineral waxes,
which includes ozokerite (in Galicia and Roumania, and Tscheleken, an
island in the Caspian Sea, B. 16, 1547) * and neftigil (in Baku). For
their purification the crude paraffins are treated with concentrated
sulphuric acid, to destroy the resinous constituents, and are then
re-distilled. Ozokerite that has been bleached without distillation,
bears the name ceresine, and is used as a substitute for beeswax.
Paraffins that liquefy readily and fuse between 30° and 40° are known
as vaselines, and find application as salves.
When pure, the solid paraffins form a white, translucent, leafy,
crystalline mass, soluble in ether and hot alcohol. They melt between
45° and 70°, and are essentially a mixture of saturated hydrocarbons
boiling above 300°, but appear to contain also those of the formula
CnH2n. Chemically, paraffin is extremely stable, and is not attacked
by fuming nitric acid. Substitution products are formed when chlorine
acts upon paraffin in a molten state.
B. Unsaturated Hydrocarbons
defines, Alkylenes, Alkenes.
2.
3. CwH2n_2
4.
Acetylene Series, Alkines.
Diolefine Series, Alkadienes.
Olefinacetylene Series.
Diacetylene Series.
5. CnH2n-6
I. OLEFINES Or ALKYLENES,
The hydrocarbons of this series contain two hydrogen atoms less
than the saturated hydrocarbons. All contain two adjacent carbon
atoms united doubly to each other, or, as commonly expressed, they
contain a double carbon linkage. The defines readily take up two
80 ORGANIC CHEMISTRY
univalent atoms or radicals, whereby the double carbon union becomes
converted into a single one : paraffins or their derivatives result.
The names of the defines are derived from the names of the alcohols containing
a like carbon content, with the addition of the suffix " ene " : ethylene from ethyl,
propylene from propyl, and finally for the series we have the name : alkylenes. In
the " Geneva names " the yl of the alcohol radicals is replaced by " ene " : [ethene]
from ethyl, [propene] from propyl, and for the series : alhencs. In long series the
position of. the double union" is indicated by an added number (p. 70). Methylene,
=CH2, the hydrogen compound corresponding to CO, has thus far resisted isola-
tion as completely as — CH2. Two =CH2 groups invariably unite to form ethylene
— the first member of the series. Beginning with the second member of the series,
propylene, we find, as we advance, that the olefines have isomers in the ring-
shaped hydrocarbons — the eyeloparaffins or cyclic limit hydrocarbons :
Propylene is isomeric with trimcihylene — [Cyclopropane] . a>CH
L/rl j
The three butylenes are isomeric with tetramethylene — CH2.CH2
[Cyclobutane] CH2.CH2
The five amylenes are isomeric with pentamethylene — CH2.CH2x~Tr
[Cyclopentane] CH2.CH2^
The hexylenes are isomeric with hexamethylene — . . < CH2-CH2-CHa
hexahydrobenzene [Cyclohexane] CH2-CH2-CH2
The heptylenes are isomeric with — heptamethylene . . . CHz.CHz.C
suberane [Cycloheptane] CH2.CHZ.C
The eyeloparaffins are more closely allied, in chemical character, to the
paraffins than to their isomeric olefines, as they only contain singly linked carbon
atoms. They lack in additive power, as the addition of hydrogen could only
result in a rapture of the ring. Together with their derivatives, the eyeloparaffins
form the transition from fatty bodies to the aromatic compounds. They will not
be considered in the discussion of the olefines.
Olefine isom&rs appear first with butylene. Three modifications are possible
and are known :
(i) CH8— CH2— CII-CHa (2) CH3— CHrrCH— CH8 (3) CH2=C(CH8)8
Butylene [Butene-i]. Pseudobutylene [Butene-s]. Isobutylene [Methyl Propene].
Pseudobntylene has been obtained in two geometrical isomeric modifications
(p. 33) (A. 313, 207) :
CH8\ /CH, CH8V /H
>C=C< >c=c\
W XH H/ XCH,
Plane-symmetrical Axially-symmetrical
Pseudobutylene , b-p. 1-1-5°. Pseudobutylene, b.p. 2-5°.
Five olefines of the formula C5H10 are pDssible.
Ethylene may be taken a.s being typical of the olefines.
Ethylene, CHS«CH2 [Ethene], Elayl;m.p. -169°, b.p.760 -105°,
is also known as oil-forming gas, because, by the action of chlorine, it
yields a.n oily compound, ethylene chloride (q.v.). This property has
given the name to the whole series. Ethylene is formed during the
dry distillation of many organic bodies, and is, therefore, present in
illuminating gas to the extent of 4 to 5 per cent.
Methods of Formation. — (i) By heating methylene iodide, CH2I2,
with metallic copper to 100° in a sealed tube (Butlerow) :
CH2
2CH2I2+4Cu=!l +2Cu2I8.
CH2
(2) By the action of metallic sodium on ethylidene chloride
OLEFINES 81
(Tollens) and ethylene chloride, as well as from zinc and ethylene
bromide :
CHC12 CH2C1 CH2 CH2Br CHa
or | + 2Na= II +2NaCl; | +Zn= || +ZnBr..
CH2C1 CH2 CH2Br CH2
CH8
(3) By the action of zinc and ammonia on copper acetylide ; and
of a mixture of acetylene and hydrogen in the presence of finely
divided metals, such as nickel :
CH CH.
II! +2H=|| .
CH CHa
(4) When alcoholic potassium hydroxide acts on ethyl bromide :
CH2Br CHa
+ KOH=|| + KBr+HaO.
CH8 CHa
(5) Upon heating ethyl sulphuric acid (p. 82). This is the method
usually pursued in the laboratory for the preparation of ethylene
(A. 192, 244) :
S02<g£*H»=H2S04+C2H4.
Sulphuric acid may be replaced, with advantage, by syrupy phos-
phoric acid, because no charring occurs when this acid is employed.
The ethylene is evolved when alcohol is slowly dropped into the acid
which is heated to 200-220° (C. 1901, II. 177).
(6) By the electrolysis of a concentrated solution of potassium
succinate (see ethane) (KekuU) :
CH2:CCVK HOiH CHa H
CHJC02K HO;H CHa ' H*
Ethylene is a colourless gas, with a peculiar, sweetish odour. Water
dissolves but small quantities of it, whilst alcohol and ether absorb
about 2, volumes. It is liquefied at o°, at a pressure of 42 atmo-
spheres. Its critical temperature is 13°, and its critical pressure
exceeds 60 atmospheres. It is suitable for the production of very
low temperatures (B. 32, 49). It burns with a bright, luminous flame,
decomposing initially into methane and acetylene (B. 27, R. 459). A
mixture of ethylene and chlorine when ignited burns slowly with a
very sooty flame. It forms a strongly explosive mixture with oxygen
(3 volumes).
(1) In the presence, of platinum black, it will combine with hydrogen
at ordinary temperatures, yielding C2H6 (B. 7, 354).
(2) It is absorbed by concentrated hydrobromic and hydriodic
acids at 100°, with the production of C2H5Br and C2H5I :
CHa CHa CH8 CHaI
II +H2= | ; || +HI =
CH, CH8 CH2 CH,
VOL. I. G
82 ORGANIC CHEMISTRY
(3) It combines with sulphuric acid at 160-174°, forming ethyl
sulphuric acid; and with sulphuric anhydride it yields carbyl
sulphate :
CH2 /OH /O.C2H5 CH2 CHa.O.SOa
|| +S02/ =S02< ; II +2SO,= I
CH, \>H 'X)H CHa CHa-SOa
(4) It unites readily with chlorine and bromine, as well as with
iodine in alcoholic solution, and with the two iodine chlorides (B. 26,
368);
CHa CH2Br CH2 CH8C1
II +Bra= | ; || +C1I= |
CHa CHaBr CHa CHaI
(5) It forms the monochlorhydrin of glycol by its union with
hypochlorous acid.
(6) Ethylene glycol itself, however, is produced by carefully
oxidizing ethylene with dilute potassium permanganate, which acts
as if hydrogen peroxide added itself to the ethylene :
CHa CHaCl CHa OH CH2OH
|| + C10H =| ; || + | = | ' .
CHa CHaOH CHa OH CHaOH
Ethylene combines with mercuric salts in solution forming such compounds
as CHa(OH).CH8HgCl, ClHgCH2.CH2.O.CH2.CH2.HgCl, which can be looked
upon as being derivatives of ethylene glycol (B. 34, 2906).
Ethylene Homologues. — Higher defines are found in the tar
obtained from bituminous shales (B. 28, 496), in American petroleum
(C. 1906, II. 120), and apparently also in coal tar (B. 38, 1296). Just
as ethyl alcohol is the most suitable substance for the preparation of
ethylene, so its homologues are the best parent substance for the pro-
duction of the homologues of ethylene.
Methods of Formation. — (i) The halogen derivatives, readily formed
from the alcohols, are digested with alcoholic sodium or potassium
hydroxide.
In this reaction the haloid (especially the iodide) derivatives corresponding with
the secondary and tertiary alcohols break up very readily (C. 1900, I. 1063).
Propylene has been obtained from isopropyl iodide, a-butylene from the iodide of
normal butyl alcohol, fi-butylene from secondary butyl iodide, and isobutylene
from the iodide of tertiary butyl alcohol. Many others have been prepared in
the same way. Heating with lead oxide effects the same result (B. 11, 414).
Tertiary iodides yield defines when treated with ammonia.
' / (2) Distillation of the monohydric alcohols, C»H2n+1OH, with
dehydrating agents, e.g. sulphuric acid, zinc chloride, and phosphorus
pentoxide (C. 1901, II. 77), or boron trioxide or oxalic acid (C. 1898,
I. 557 ; B. 34, 3249) causes the removal of one molecule of water,
and, thereby, the production of the corresponding olefine. Isomeric
and polymeric forms are produced together with the normal olefmes.
The secondary and tertiary alcohols decompose particularly readily. The
higher alcohols, not volatile without decomposition, undergo the above change
when heat is applied to them ; thus cetene, C^.H.*, is formed on distilling cetyl
alcohol, C18H340.
OLEFINES 83
When sulphuric acid acts on the alcohols, acid esters of sulphuric acid (the
so-called acid ethereal salts — see these) appear as intermediate products. When
heated they break down into sulphuric acid and CnH2« hydrocarbons (comp.
ethylene).
The higher olefines may be obtained from the corresponding alcohols by dis-
tilling the esters they form with the fatty acids. The products are an olefine and
an acid (B. 16,3018) :
C,6H31C02C12H25 = C16H81C02H+C12H24.
Dodecyl Ester of Palmitic Dodecylene.
Palmitic Acid. Acid.
Also, xanthogenic acid ester decomposes at relatively low temperatures into
olefines, carbon oxysulphide and mercaptans (B. 32, 3332).
(3) Halogen addition products of the olefines (see ethylene) react
with metals to form free olefines.
(4) By heating alky] ammonium phosphates (B. 34, 300).
(5) The electrolysis of the potassium salts of saturated dicarboxylic
acids (see ethylene) results, as follows : glutaric acid yields propylene
(C. 1904, II. 823).
(6) When zinc alkyls act on bromo-olefines, the olefines are
liberated, e.g. CH2=CHBr, which with zinc ethyl yields a-butylene
or ethyl ethylene.
(7) Higher olefines have also been obtained by the reaction of
Wurtz (p. 75).
(8) The formation of higher alkylenes by the linking of lower
members with tertiary alcohols or alkyl iodides, is noteworthy. Thus,
from tertiary butyl alcohol and isobutylene, by means of zinc chloride
or sulphuric acid, isodibutylene is obtained (A. 189, 65 ; B. 27, R. 626):
(CHa),C.OH+CH2 : C(CH3)2=(CH8)3C.CH : CfCH^-J-H^O.
Isodibutylene.
The action of the ZnCl2 is due to the intermediate formation of addition
products, e.g. trimethyl ethylene and zinc chloride unite to the crystalline com-
pound (CH8)2C=CHCH8,2ZnCl,. Water converts this into dimethyl ethyl
carbinol, whilst hydrogen chloride produces the chloride of the latter. This
chloride and trimethyl ethylene then unite to form a saturated chloride, which,
on distillation, splits off hydrochloric acid and yields diamylene (B. 25, R. 865) ;
see also polymerization of olefines.
Tetramethyl ethylene (B 18, 398) is produced by heating 0-isoamylene
(see p. 85) with methyl iodide and lead oxide :
(CH8)8C : CH.CH8+CH8I = (CH8)aC : C(CH8)a+HI.
In the dry distillation of many complicated carbon compounds the olefines are
produced together with the normal paraffins, hence their presence in illuminating
gas and in tar oils (see ethylene).
Properties and Reactions of the Olefines. — So far as physical
properties are concerned, the olefines resemble the normal hydro-
carbons ; the lower members are gases, the intermediate ethereal
liquids, whilst the higher (from C16H32 upwards) are solids. Generally,
their boiling points are a few degrees higher than those of the corre-
sponding paraffins.
In chemical properties, on the other hand, they differ greatly from
the paraffins. Being unsaturated, they can unite directly with two
univalent atoms or groups, whereby the double bond becomes
single.
84 ORGANIC CHEMISTRY
They combine :
(1) With nascent hydrogen, forming paraffins with a like number
of carbon atoms (see ethylene).
(2) With HBr and, with especial readiness, with HI.
The halogen acids attach themselves in such a manner to the mono- and di-
alkyl ethylenes that the halogen unites with the carbon atom combined with fewest
hydrogen atoms (B. 39, 2138). As such alkylized ethylenes can be prepared from
the proper primary alcohols by the splitting-off of water, these reactions can be
employed to convert primary into secondary alcohols, and also tertiary alcohols
(p. 107).
The defines are also capable of combining with the fatty acids (B. 25, R. 463),
but only when exposed to high temperatures (290-300°), e.g. :
CsH11CH=CH3+CH,.COaH=C5H11CH(O.CO.CH,).CHt.
Pentyl Ethylene. Sec.-Heptyl Acetate.
(3) Concentrated sulphuric acid absorbs them, forming ethereal
salts. This is a reaction which can be used to convert olefines into
alcohols, and also to separate them from paraffins (see p, 81), which are
much more resistant to the action of sulphuric acid (C. 1899, I. 967).
(4) They form dihalides (see ethylene) with C12, Br2, 12, C1I. These
can be viewed as the haloid esters of the dihydric alcohols — the glycols,
into which they can be converted.
(5) They yield chlorhydrins with aqueous hypochlorous acid. These are the
basic esters of the glycols (see ethylene), in which the hydroxyl is attached to
the less hydrogenized carbon atom (C. 1901, II. 1249).
(60) Potassium permanganate in dilute solution changes them to
glycols (B. 21, 1230, 3359).
The last three reactions afford a means of converting monacid (monohydric)
alcohols into dihydric alcohols or glycols (q.v.). The olefines take an intermediate
part in these changes, e.g. :
CHa.Br\
r^i \
CH.OH CH, rOT,.Hr \ CHa.OH
CHf CH CH..OH -rf CH,.OH
'-H /
CH2C1/
(66) Energetic oxidation severs the double bond of the olefines.
Ozone, O3, becomes added at the double bond to form ozonides, which
are decomposed by water into two molecules of aldehydes or ketones
(A. 343, 311) :
RtC=CR'a -» R2C— CR'f -> RBCO-f OCR',.
0,
(7) N2O3 and N2O4 convert the olefines into nitvosites and nilrosates (q.v.).
They are the nitrites and nitrates of oximes of hydroxyaldehydes and hydroxy-
ketones. The olefines can even take up nitrosyl chloride (B. 12, 169; 27, 455,
R. 467; C. 1901, II. 1201). The resulting addition products are changed by
boiling water, alcoholic potassium hydroxide, and ammonia back into the olefines
(B. 29, 1550).
(8) Polymerization of Olefines. — When acted on by dilute sulphuric acid
(B. 29, 1550), zinc chloride (C. 1897, I. 360), boron fluoride, and other substances,
many olefines undergo polymerization even at ordinary temperatures, in con-
sequence of the union of several molecules. Thus, there result from isobutylene,
ACETYLENES 85
C^H,: di-isobutylene, C8H16; from isoamylene, C6H10 : di-isoamylene, Ci0H20 ;
tri-isoamylene, C15H30, etc. Butylene and propylene behave in the same way.
Ethylene, on the other hand, is not condensed by sulphuric acid or by boron
fluoride. The polymers act like unsaturated compounds, and contain a pair of
doubly linked carbon atoms.
Although ethylene itself undergoes no alteration, yet its unsymmetrical
halogen substitution products polymerize very readily (see p. 98).
Below are given the boiling points of some of the homologues of
ethylene. It is most convenient to designate them as alkyl substi-
tution products of ethylene.
Propylene ....... CH3CH=CHa —48° gaseous
(B. 33, 638).
Ethyl Ethylene ..... CH3CH2CH=CH2 -5°
Eth>'lene CH,CH=CH.CH3 . go)>
unsym. Dimethyl Ethylene . . (CH3)aC=CH2 —6°
n.-Propyl Ethylene .... CH3CHaCH2CH=CH2 +39°
a-Amylene
Isopropyl Ethylene . . . . (CH3)2CH.CH = CH2 +21° (C. 1900, I.
a-Isoamylene 1195)
sym. Methyl Ethyl Ethylene . CH,.CH2.CH=CH.CH3 +36°
/3- Amylene
unsym. Methyl Ethyl Ethylene . CH3.CH2Xn ~u
y-Amylene CH8^— 'H2
Trimethyl Ethylene .... (CH3)2C=CH.CH8 +36°
/Msoamylene
Tetramethyl Ethylene . . . (CH3)2C=C(CH8)2 +73° (B. 27 454).
Many other higher members of this series are known. Of these, trimethyl-
ethylene or /Msoamylene, pental, possesses a significance, as it is used in the
preparation of the so-called amylene hydrate or tertiary amyl alcohol. jS-Iso-
amylene constitutes the chief ingredient of the mixture of olefines resulting
from the action of zinc chloride on the amyl alcohol of fermentation (A.
190, 332 ; B. 36, 2003). The formation of tetramethyl ethylene from pinacolyl
alcohol or methyl-tert.-butyl carbinol is of interest because it appears to be
a reversal of the formation of pinacolin from pinacone (q.v.) (B. 24, 3251,
footnote). Both tri- and tetramethyl ethylene can be prepared from amylene
hydrate and pinacolyl alcohol respectively, by heating them with anhydrous
oxalic acid.
HYDROCARBONS, CnH2n_2
Two groups of hydrocarbons having this empirical formula exist :
The acetylenes or alkines with triple linking, and
The allylenes with two double linkages.
The allylenes are also called diolefines. The difference in structure
is clearly shown in their different chemical behaviour. The acetylenes
(with group^CH) alone have the power of entering into combinations
in which the hydrogen of the group^CH is replaced by metals. The
names adopted for the acetylenes by the Geneva Congress are formed
by substituting the ending " ine " for the ending yl of alcohol radicals
with like carbon content, hence the designation alkines.
2. ACETYLENES OR ALKINES,
The position of acetylene, the first member of this series, among
the aliphatic hydrocarbons is very prominent, on account of its technical
importance, and its direct formation from carbon and hydrogen.
Some acetylenes are distinguished by their power of polymerization,
which result in the formation of simple aromatic hydrocarbons.
86 ORGANIC CHEMISTRY
Acetylene [Ethine] CH=CH was first observed by Edmund Davy.
Berthelot introduced the name acetylene and studied the hydrocarbon
carefully.
(1) Berthelot effected the synthesis of acetylene by passing the elec-
tric spark between carbon points in an atmosphere of hydrogen (p. 64) :
2C+H,=CH=CH.
(2) It results in the decomposition of the carbides of the alkali
earths by water (B. 25, R. 850 ; 27, R. 297) :
C\
The addition of formaldehyde solution retards the evolution of acetylene from
calcium carbide (C. 1 900, 11.1150). The gas is always contaminated by phosphine,
which can be removed by the action of bromine water, or better by means of a
feebly acid solution of copper sulphate and of chromic acid in sulphuric acid
(C. 1900, I. 789 ; B. 32, 1879). On a large scale bleaching powder or bleaching
powder and lead chromate (to avoid the evolution of free chlorine) are recom-
mended as purifiers (C. 1900, I. 236 ; II. 229). Metal gas holders for use with
acetylene are best avoided (C. 1900, I. 954). The gas is employed to an ever-
increasing extent for illumination and for cutting and melting metals (by means
of the oxygen-acetylene flame).
(3) It may be prepared from methane by converting it into
chloroform, from which chlorine is removed by means of red hot
copper or heated metallic sodium (Fittig). Bromoform, CHBr3 (B.
25, R. 108), and iodoform, CHI3, are very readily changed by silver
or zinc dust into acetylene :
CH
2CH< ^2CHC18 HII •
CH
(4) Formerly acetylene was always made from ethylene bromide
by the action of alcoholic potassium hydroxide (A. 191, 268). At first
the ethylene bromide loses a molecule of hydrogen bromide and
becomes monobromethylene or vinyl bromide, which in turn loses a
molecule of hydrogen bromide with the production of acetylene :
CH2OH CH, Br2 CHaBr CHBr
Ml > I +KOH=|| -j-KBr+H20
CH, CH2Br CH2
CHBr CH
|| +KOH = ||| + KBr+H20.
CH, CH
2
CH,
As ethylene is invariably obtained from ethyl alcohol and sul-
phuric acid, this method allies acetylene genetically with ethyl
alochol.
Acetylene is also formed when quarternary piperazonium salts
(q.v.) are boiled with sodium hydroxide solution (B. 37, 3507).
(5) Acetylene is also produced by the electrolysis of the alkali
salts of the two isomeric dicarboxylic acids — maleic and fumaric
(Kekule, A. 131, 85) :
CHC02
I! I
CH;CO,
K HOiH CH H
.-•
ACETYLENES 87
(6} Acetylene is given off when sodium hydroxide solution acts on propargyl
aldehyde :
CH=C-CHO+HONa=CHrECH+CHOONa.
(7) It is worthy of note that potassium acetylene-monocarboxylate and silver
acetylene-dicarboxylate are readily converted, when warmed with water, into
carbon dioxide and acetylene, and silver acetylide respectively (A. 272, 139).
The stability of the dicarboxylic acids is very much influenced by the manner
of union of the carbon atoms, to which the carboxyl groups are attached.
AgOaC.C=C.CO2Ag=AgC=CAg+2COr
Acetylene is further formed when many carbon compounds, like
alcohol, ether, methane, ethylene, etc., are exposed to intense heat
(their vapours conducted through tubes heated to redness). Hence
it is present in small amount in illuminating gas, to which it imparts
a peculiar odour.
Properties. — Pure acetylene is a gas of ethereal, agreeable odour,
and may be liquefied at -f i° and under a pressure of 48 atmospheres.
It solidifies when rapidly vaporized and then sublimes at —82°
(B. 33, 638). It is a strongly endothermic compound, of which the
heat of formation is — 61 Cal. It is slightly soluble in water ; more
readily in alcohol and ether, and easily in methylal, acetal, ethyl
acetate, and acetone (C. 1897, I. 800). It burns with a very smoky
flame, and with air (9 vols.), but especially with oxygen (2j vols.),
forms an exceedingly explosive mixture (Anschutz). Under certain
conditions acetylene decomposes with generation of heat and sudden
increase in volume. When subjected to high pressure, and especially
when liquefied this decomposition is extremely dangerous (C. 1897,
II. 332 ; 1899, 1. 1018).
Reactions. — Nascent hydrogen converts acetylene into C2H4 and
C2H6. Ordinary hydrogen (2 vols.) and acetylene (i vol.), passed
over platinum black, form C2H6 (B. 7, 352). Finely divided Ni, Co,
Fe, and Cu behave similarly (C. 1899, I. 1270 ; 1900, II. 528),
producing at the same time high molecular cork-like condensation
products (B. 32, 2381). Acetylene combines with HC1 and HI,
forming CH3CHC12 and CH3CHI2. ,
Acetylene reacts with chlorine gas in the sunlight with a slight explosion. It
forms a crystalline compound with SbCl6, which is changed by heat into dichlor-
ethylene, CHC1 : CHC1, and SbCls. With bromine it forms C,HaBrt and CaH,Br4
(A. 221, 138).
In contact with HgBra and other mercury salts acetylene unites with water to
yield aldehyde, which is also produced when acetylene alone is heated with water
to 325°, or when it is passed into dilute sulphuric acid in presence of HgO (C. 1898,
II. 1007). Fuming sulphuric acid absorbs acetylene, forming acetaldehyde
di-sulphonic acid and methionic acid (q.v.). With HC1O and HBrO acetylene
forms dichlor- and dibromacetaldehyde (C. 1900, II. 29). Acetylene unites with
an aqueous solution of mercuric nitrate to form a substance —
OHg
which can also be obtained from acetaldehyde ; similarly, trichloromercuriacetalde-
hyde (ClHg)3C.CHO is produced with mercuric chloride solution (B. 37, 4417).
In the case of mercuric nitrite or chlorate, however, the similar compounds which
are formed, are explosive (B. 38, 1999). In diffused daylight, contact with
88 ORGANIC CHEMISTRY
potassium hydroxide solution and air, acetylene changes into acetic acid. Oxyda-
tion with nitric acid leads to the formation of nitroform CH(NO2)3, and other
bodies (C. 1901, II. 177). Acetylene unites with diazomethane, producing
pyrazole (see Vol. II.).
Acetylene polymerizes at a red heat, three molecules uniting to
form one molecule of benzene, C6H6. This is one of the most striking
transitions from the aliphatic to the aromatic series and, at the same
time, constitutes a synthesis of the parent hydrocarbon of aromatic
substances (Berthelot).
This conversion will take place at the ordinary temperature if acetylene be
passed over pyrophoric iron, nickel, cobalt, or platinum sponge (B. 29, R. 540 ;
see also above).
Metallic Derivatives of Acetylene. — The two hydrogen atoms of
acetylene can be replaced by metals. The alkali and alkali earth
acetylides are stable even when heated, but are decomposed by water
with the liberation of acetylene. Copper and silver acetylides when
dry are exceedingly explosive, but are stable in the presence of water.
Acids evolve pure acetylene from them.
Sodium Acetylides, CH=CNa and CNa=CNa are produced when sodium is
heated in acetylene gas (C. 1897, I. 966 ; 1899,1.174; 1904,11.1204). Calcium
Acetylide or Calcium Carbide, C2Ca, is formed when calcium oxide is reduced by
carbon at a red heat (Wohler, 1862), and when a mixture of calcium oxide and sugar
carbon is heated in electric furnaces to 3500° (Moissan, B. 27, R. 238 ; C. 1899,
II. 1093). It is a homogeneous mass, colourless in its purest form but usually
obtained of a grey tint, and shows a crystalline fracture. If fragments of
calcium carbide are dropped into a tall glass cylinder filled with saturated chlorine
water, the liberated acetylene will combine with the chlorine with the production
of flame. Gas-bubbles, giving out light, rise in the liquid and when they reach
the surface burn there with a smoky flame Lithium Carbide, C2Li2, is obtained
from lithium carbonate and carbon (B. 29, R. 210). Caesium Carbides, C2HCs
and C2Csa, and Rubidium Carbides, C2HRb and C2Rb2, are produced when
acetylene is led into solutions of caesium-ammonium and rhubidium-ammonium
in ammonia (C. 1903, II. 105).
Silver Acetylide, C2Ag2, a white precipitate, and Copper Acetylide, C2Cu2
(B. 25, 1097 ; 26, R. 608 ; 27, R. 466), a red precipitate, are formed when acetylene
is conducted into ammoniacal silver or cuprous chloride solutions. The dry salts
explode violently when they are heated ; the silver salt even does this when gently
rubbed with a glass rod. In a solution of silver nitrate acetylene precipitates the
compound HC=CAg.AgNO3 (B. 28, 2108). Gold Aeetylide, C2Au2, a yellow pre-
cipitate, is obtained from acetylene and a solution of ammoniacal gold-sodium
thiosulphate (C. 1900, I. 755). Pure acetylene is set free by acids from these
metallic compounds. The copper salt serves for the detection of acetylene in a
mixture of gases. Mercury Acetylide, C2Hg, is thrown out as a white precipitate
from alkaline solutions of mercuric oxide. It explodes violently when heated
rapidly.
Acetylene Homologues.— The diolefines are isomeric with the
homologues of acetylene. They contain a like number of carbon
atoms, e.g. allene, CH2=C=CH2, is isomeric with methyl acetylene
(allylene) CH3.CEECH; divinyl, CH2 : CH.CH : CH2, with dimethyl
acetylene (crotonylene), CH3.C i C.CH8.
The higher homologues, just like acetylene, are mostly prepared from
the mono-halogen and di-halogen substitution products of the defines,
the olefine dibromides, by the action of alcoholic potassium hydroxide,
e.g. from CH3CC1=:CH2: allylene/ from CH3.CHBr.CHBr.CH3 :
ACETYLENES 89
crotonylene, CH3(SC.CH3. In this manner a host of higher acetylene
homologues have been prepared from the dibromides of the higher
defines (B. 33, 3586). Alkines are also obtained by the action of
alcoholic potassium hydroxide on aldehydic and ke tonic chlorides,
e.g. cenanthylidene chloride yields cenanthylidene CH3[CH2]4C=CH
(C. 1900, II. 1231).
When strongly heated with alcohol the acetylene formed frequently
undergoes a transposition ; thus, ethyl acetylene, C2H5.C^CH, yields dimethyl
acetylene, CH3.C=C.CH., and propyl acetylene, C3H7.C=CH, furnishes ethyl
methyl acetylene, C2H6.C^C.CH3, etc. (B. 20, R. 781). Symmetrically consti-
tuted bodies may be formed from unsymmetrical compounds.
The reverse transposition sometimes occurs on heating with metallic sodium ;
ethyl methyl acetylene passes into propyl acetylene, and dimethyl allene,
(CH3)2C=C=CH2, yields isopropyl acetylene, etc. (B. 21, R. 177).
Acetylenes are also formed in the electrolysis of unsaturated dibasic acids :
thus, allylene is formed in the electrolysis of the alkali salts of mesaconic and
citraconic acids.
Acetylene and its homologues unite with hydrogen to form olefines,
which in turn pass into paraffins. By the addition of halogen acids or
the halogens mono- and di-haloid olefines are formed. The further
addition of halogen acids and halogens to these yields di-, tri-, and
tetra-halogen substitution products of the paraffins.
Hypochlorous and hypobromous acids convert the alkines into dichloro- and
dibromo-ketones, e.g. allylene CH3.C^CH with HBrO yields asymmetric dibro-
macetone (C. 1900, II. 29) ; also, methyl ethyl acetylene C2H6C^C.CH3 with
2HC1O gives a-dichloropropyl methyl ketone CH3CHaCCl2.CO.CH3 (B. 28, R. 781).
When heated with water to 325°, the alkyl acetylenes yield ketones (B. 27, R. 750 ;
28, R. 173).
A characteristic of all mono-alkyl acetylenes, as well as of acetylene
itself, is their power to yield solid crystalline compounds by the action
of ammoniacal solutions of silver and cuprous salts, from which they
can be regenerated by warm hydrochloric acid. This behaviour
affords a very convenient method for separating the acetylenes from
other gases, and obtaining them in a pure condition.
The acetylenes are absorbed by concentrated sulphuric acid ; some
even polymerize to aromatic derivatives.
In the presence of HgBr2 and other salts of mercury, the acetylenes unite
with water: acetylene yields aldehyde, C2H4O ; allylene, C3H4, acetone, C3H8O ;
valerylene, C6H8, a ketone, C6H10O (B. 14, 1540, and 17, 28). Very often
moderately dilute sulphuric acid will act in the same way ; methyl n-propyl
acetylene gives two isomeric ketones when treated with approximately 8 per
cent, sulphuric acid.
The boiling points of some of the acetylenes are as follows : —
B.P.
Allylene, Methyl Acetylene [Propine] CH3C=CH Gas
Crotonylene, Dimethyl Acetylene [2-Butine] . . . CH3C=CCHS 27°
Ethyl Acetylene [3-Butine] C2H6C=CH 18°
Methyl Ethyl Acetylene OPentine] C2H6C=CCH3 55°
n.-Propyl Acetylene OPentine] n-C3H7C=CH 48"
Isopropyl Acetylene fo-Methyl-i-Butine] . . . (CH3)2CH.C=CH 28°
Methyl n.-Propyl Acetylene [4-Hexine] .... n-C3H7CEEC.CH, 84°
Allylene and crotonylene deserve consideration, because, when brought into
contact with concentrated sulphuric acid, they pass into symmetric trimethyl-
benxene and hexamethyl-benzene.
3CH3C=CH >- C6Hs[i,3,5](CH3)3— Mesitylene.
3CH,C^CCH,— >- CC(CH3)6— Hexamethyl Benzene.
90 ORGANIC CHEMISTRY
Interaction between sodium alkines and acid chlorides produces the alkine
ketones ; e.g. sodium oenanthylidene and acetyl chloride yield cenanthylidene
methyl ketone CH3[CH2] 4C^C.CO.CH3. Sodium alkines and trihydroxy methyl-
ene give sodium alcoholates ROXH2OH. CO2 combines with the sodium
alkines forming acetylene carboxylic acids: sodium acetylene gives sodium
propiolate CH^C.COONa.
On the higher alkyl acetylenes, see B. 25, 2245 ; 33, 3586.
3. DIOLEFINES,
The diolefines are not capable of forming silver and copper com-
pounds, but give precipitates with mercuric sulphate and chloride in
aqueous solution (B. 21, R. 185, 717 ; 24, 1692).
The " Geneva names " for the diolefines are derived by inserting a
"di," for the number of double linkages, before the final syllable
" ene " — e.g. [propadiene] for symmetric allylene.
The diolefines are prepared by splitting off hydrobromic acid from
the paraffin dibromides by means of alcoholic potassium hydroxide,
pyridine or quinoline ; as well as by heating the diamine phosphates
(B. 34, 300).
Diolefines with a "conjugated double binding "— CH=CH.CH
=CH — often add bromine or hydrogen in the 1,4 position ; e.g.
butadiene gives i,4-dibromobutene BrCH2.CH=CH.CH2Br.
Ozone unites with the diolefines forming diozonides, of which the
decomposition (p. 84, 6b), caused by water, assists in the elucidation
of its constitution. Atmospheric oxygen is also absorbed with greater
or less ease by diolefines. On polymerization, see B. 35, 2130, etc.
Of the numerous hydrocarbons of this class some are worthy of note because
of their genetic relations. They are :
Allene, sym. Allylene [Propadiene] . CH,=C=CH2 Gas
Divinyl, Erythrene [i,3-Butadiene] . CHa=CH— CH=CH2 B.P.— 5°
Pyrrolylene
Piperylene, a-Methyl Butadiene . . CH2=CH— CH=CH— CH, 42°
Isoprene, 0-Methyl Butadiene . . . CH2=CH— C(CH8)=CH2
Di-isopropenyl, jSy-Dimethyl Buta-
diene CH2=C(CH8)— C(CH8)=CH2
i, i,3-Trimethyl Butadiene . . . . (CH8)2C : CH.C(CH3) : CH2 93°
Diallyl [i,5-Hexadiene] . . . . CH2=CH— CH2— CHa— CH=CH2 59°
2,5-Dimethyl-i,5-Hexadiene . . . CH2=C(CH8).CH2.CH2.
C(CH8)=CH2 ,,137°
i,i,5-Trimethyl-i,5-Hexadiene . . . (CH,)2C: CH.CH2.CH2.
C(CH8)=CH2 „ 141°
Conylene [i,4-Octadiene] .... CH2=CH— CH2— CH =
CH— CH2CH2CH8 ,,126°
Allene is obtained by electrolysis of potassium itaconate (p. 515) ; also by
heating bromomethyl acrylic acid, and by decomposition of dibromopropylene
CH2Br.CHBr : CH2 by zinc dust. Contrary to allylene, it is not absorbed by
ammoniacal silver nitrate, but, like it, gives the same white mercury precipitate,
which is decomposed by acids, yielding acetone (A. 342, 185).
Divinyl, Erythrene, or Pyrrolylene is found in compressed illuminating gas,
and serves as the parent substance for the synthesis of erythritol, from which
it results on boiling with formic acid. It is called pyrrolylene because it is formed
in the breaking down of pyrrolidine or tetrahydropyrrole (Vol. II.) (B. 19, 569 ;
A, 3_08, 333).
35
Piperylene and Conylene are formed in the same manner from piperidine
i ll'1 an? fconiine (Yo1- IL) (B- 14» 665> 710 • A. 3*9> 226)- Piperylene is
ie
. . -* •• *> •"j f •• ; * ...
also produced from 2,4-dibromopentane by the abstraction of 2HBr by quinoline
(C. 1901, II. 183).
HALOGEN DERIVATIVES OF THE HYDROCARBONS 91
Isoprene, a distillation product of caoutchouc, is closely related to the
terpenes. It is called a hemiterpene, and by spontaneous polymerization passes
into dipentene or cinene (Vol. II.), and then back into caoutchouc (B. 25, R. 644).
This latter change can be accelerated by the catalytic action of a number of
substances, notably metallic sodium.
i,i,3-Trimethyl-butadiene is obtained from mesityl oxide by methyl magne-
sium iodide, when water is split off from the olefine alcohol first produced (B. 37,
3578).
i,i,5-Trimethyl-i,5-hexadiene is similarly produced from methyl heptenone.
Its diozonide (p. 90) on decomposition yields laevulinic aldehyde (A. 343, 362).
2,5-Dimethyl-i,5-hexadiene is obtained, together with an isomeric hydro-
carbon, from 2,5-dimethyl-2,5-dibromohexane ; its diozonide yields formaldehyde
and acetonylacetone (A. 343, 365).
Diisopropenyl is obtained from tetramethyl ethylene dichloride (from HC1
and pinakone) and alcoholic potassium hydroxide (C. 1900, II. 1061).
Diallyl results from the action of sodium on allyl iodide ; its ozonide yields
succinic aldehyde (A. 343, 360).
4. OLEFINE ACETYLENES
By this name are understood the hydrocarbons containing both doubly and
trebly linked pairs of qarbon atoms in their molecules. Many of them are known,
but none deserve special consideration.
5. DIACETYLENES, C^H^.e
Diacetylene, HC • C.C • CH, is formed from diacetylene dicarboxylic acid. It is
a gas that yields a yellow precipitate with an ammoniacal silver solution. The two
hydrocarbons, dipropargyl and dimethyl di-acetylene, are isomeric with benzene.
Dipropargyl, CH • C.CH2.CH2.C i CH, b.p. 85°, is formed on wanning solid
crystalline diallyl tetrabromide, C,H10Br4, with aqueous potassium hydroxide.
It is a very mobile liquid, of penetrating odour. It forms copper and silver
derivatives. If dipropargyl be allowed to stand, it becomes resinous.
Dimethyl Di-acetylene, CH,.CpC.C^C.CH3, m.p. 64° ; b.p. 130°, has been
obtained from the copper derivative of allylene (B. 20, R. 564).
6. TRIOLEFINES, CnH2n_g
i,i,5,5-Tetramethyl-4-methene-i,4-pentadiene, (CH3)aC=CH.C(:CH2).CH :
C(CH3)2, b.p.! 4 55-57°, is prepared from phorone and methyl magnesium
iodide (B. 37, 3578).
II. HALOGEN DERIVATIVES OF THE HYDROCARBONS
The halogen substitution products result from the replacement of
hydrogen in the hydrocarbons by the halogens. The number N of
substitution products in the normal saturated hydrocarbons, containing
an even number of n carbon atoms, can be calculated by the formula :
n-2
*N=8X3W +2x3 *
and when n is odd : n-i i
*N=8X3 +2x3 2 •
in which the unsubstituted hydrocarbon itself is counted.
If w =2, then N =10 ; if n =3, then N =30 ; if n =4, then N= 78;
n= N=2 n=6 N=666 w= N
* For these formulae, the author expresses his thanks to Herr Geheimrath
A. V. Baeyer, of Munich.
92 ORGANIC CHEMISTRY
Thus 9 chlorine substitution products can be derived from ethane.
In the discussion of the methods of formation and the reactions
of the saturated and unsaturated aliphatic hydrocarbons, their haloid
derivatives were constantly encountered. We have also learned the
methods of producing these alkylogens, proceeding from the hydro-
carbons. They are :
(1) Formation by the direct substitution of the saturated hydrocarbons.
It was emphasized in the case of methane (p. 72) and ethane (p. 74)
that these hydrocarbons, usually so very stable, were attacked by
chlorine. A molecule of hydrogen chloride is produced for every
hydrogen atom replaced by chlorine, until the entire hydrogen content
is substituted. Methane, CH4, yields finally tetra- or perchloromethane,
CC14, whilst ethane gives hexa- or perchlorethane, C2C16.
The action of free chlorine on the paraffins is accelerated by sunlight, as is
the case when it acts on free hydrogen (Inorg. Ch.) ; by the so-called chlorine
carriers, such as iodine, which exerts its influence by the formation and decom-
position of IC13 (Inorg. Ch.) ; by the similar behaviour of SbQ6 which decomposes
by heat into SbCls and C18 ; and by A1C1, (C. 1900, II. 720), etc. In very
energetic chlorination the carbon chain is ruptured (B. 8, 1296 ; 10, 801).
The final products are CC14 and hexa- or perchlorobenzene, C8C18, with per-
chlorethane, C8Cla, and perchloromesole, C^Cle, as intermediate products (B. 24,
ion).
The substituting action of bromine may be accelerated by heat, sunlight, or
AlBr, (C. 1900, II. 720).
Iron is an excellent carrier of chlorine, bromine, and iodine. Its action seems
to be due to the formation and decomposition of compounds with ferric halides
(A. 225, 196 ; 231, 158). When it is used as a bromine carrier, every normal
hydrocarbon passes into that bromide which contains just as many bromine
atoms as it has carbon atoms (B. 26, 2436) ; a bromine atom attaches itself to
each carbon atom.
Usually iodine does not substitute well, inasmuch as the final iodine products
undergo reduction through the hydriodic acid formed simultaneously with them :
C,H7I+HI=C,H8+Ia.
In the presence of substances capable of uniting or decomposing HI (like
HIO8 and HgO), iodine frequently effects substitution :
5C8H8+2l,+HI08=5C8H7I+3HaO
2C8H8+2la+HgO=2C8H7I+H80+HgIa.
In direct substitution a mixture of mono- and poly-substitution products
generally results, and these are separated by fractional distillation or crystalliza-
tion. The attack of chlorine on a long paraffin chain, e.g. n-hexane, is directed
against the CHf groups before the CH8 (B. 39, 2138).
(2) Mono- and polychloroparafnns can be converted into mono-
and polybromoparafnns by means of AlBr3 (C. 1901, 1. 878). Among
the bromoparamns the bromine can be replaced partially by fluorine
by means of SbF3 (C. 1899, II. 281 ; 1901, II. 804). Boiling with an
alcoholic solution of an alkali iodide causes a partial replacement of
the halogens in the chloro- or bromo -paraffins (B. 39, 1951).
(3) The unsaturated aliphatic hydrocarbons, the defines (p. 84),
and acetylenes (p. 87), unite with hydrochloric, hydrobromic, and,
especially easily, hydriodic acid. The halogen acids can T>e used in
a glacial acetic acid (B. 11, 1221), or concentrated aqueous solution.
(4) The free halogens are still more easily absorbed than their
acids (p. 84).
ALKYL HALIDES 93
Two further reactions, already indicated above, bring about
halogen substitution products from aliphatic bodies containing
oxygen :
(5) Substitution of the hydroxyl group in alcohols by fluorine,
chlorine, bromine, and iodine by means of their halogen acids, or
their compounds with phosphorus (p. 132).
(6) Action of phosphorus pentachloride, phosphorus chloro-
bromide, and phosphorus pentabromide, on aldehydes and ketones.
These last methods of formation will be more thoroughly discussed
under the individual groups of halogen substitution products.
Reactions of the Halogen Derivatives. — The reactions which
take place among the halogen-paraffin compounds have been referred
to under mode of formation (2) (above). The iodine derivatives are
the most unstable. In the light they rapidly acquire a red colour,
with the separation of iodine. The chlorides and bromides, rich in
hydrogen, burn with a green-edged flame (p. 8).
(1) Nascent hydrogen (zinc and hydrochloric acid or glacial acetic
acid, sodium amalgam and water) can reconvert all the halogen deri-
vatives, by successive removal of the halogen atoms, into the corre-
sponding hydrocarbons (p. 73) :
CHCl3+3Ha=CH4+3HCl.
This change is called a retrogressive substitution.
(2) Alcoholic sodium and potassium hydroxides cause the separa-
tion of halogen acid, and the production of unsaturated com-
pounds (p. 81) :
CH,.CH2.CH8Br+KOH=CH8.CH : CHa+KBr+HaO.
Propyl Bromide. Propylene.
In this reaction the halogen carries away with it the hydrogen of the least
hydrogen! zed adjacent carbon atom (comp. p. 82). Such a decomposition
sometimes occurs on application of heat, and is favoured by the presence of
anhydrous metallic chlorides (C. 1905, II. 750).
Many other reactions of the haloid compounds will be discussed
later.
A. HALOGEN PARAFFINS
I. MONOHALOGEN PARAFFINS, ALKYL HALIDES
These are genetically connected by reactions with the alcohols, which
are almost always employed in their preparation. On comparing the
formulae of the alkylogens with those of the halogen hydrides,
HF HC1 HBr HI
C8H6F CaH4Cl C8H6Br CaH,I
it will be seen that they can be regarded as haloid acids, in which the
hydrogen atoms have been replaced by hydrocarbon residues. As the
latter, together with the water residue, constitute the monohydric
94
ORGANIC CHEMISTRY
(monacid) alcohols, they are called alcohol radicals or alkyls. Acids,
the hydrogen of which is replaceable by metals, yield acid esters when
alcohol radicals are substituted for that hydrogen. The monohalogen
alkyls are therefore discussed as haloid esters, at the head of the acid
esters of the monohydroxy-alcohols.
2. DIHALOGEN PARAFFINS, CMH2rXt
(a) Dihalogen paraffins, where two halogen atoms are attached to
two different carbon atoms, may be viewed as the haloid esters of
dihydroxy-paraffin alcohols or glycols. They can be derived from
these and will be considered together with them :
CH.C1 CH2.OH /CHjBr /CH2.OH
| | CH2< CH2<
CH2C1 CH2.OH xCH2Br XCH2.OH
Ethylene Chloride. Ethylene Glycol. Trimethylene Trimethylene
Bromide. Glycol.
(b) Dihalogen paraffins, the two halogen atoms of which are
attached to the same carbon atom, may be termed aldehyde halides,
if the carbon atom is terminal, and ketone halides, when the carbon
atom occupies an intermediate position. Indeed, these compounds
can be obtained from the aldehydes and ketones by means of phos-
phorus halides. They will, therefore, be discussed after the aldehydes
and the ketones :
CHOI, CHO /CH. /CHt
| CC1/ C0<
CH, CH, XCH, XCH,
Ethylidene Chloride Acetaldehyde. Acetone Chloride Acetone.
Aldehyde Chloride. 0-Dichloropropane.
It should be remarked here that the unsymmetric ethane dihalides
— e.g. CH3.CHC12, ethylidene chloride — have lower boiling points and
lower specific gravities than the corresponding symmetric isomers
—e.g. ethylene chloride, CH2C1.CH2C1.
3. PARAFFIN POLYHALIDES
The paraffin polyhalides, containing but one halogen atom to each
carbon atom, will be discussed after the corresponding polyhydric
paraffin alcohols.
The simplest and most important representatives of the paraffin
trihalides, in which three halogen atoms are attached to the same
carbon atom, are the methane trihalides :
CHF, CHCl, CHBr, CHI,
Fluoroform. Chloroform. Bromoform. lodoform.
They are so intimately related to formic acid and its derivatives
that they will be considered after this acid.
The most important paraffin tetrahalides are the methane tetra-
halides. They bear the same relation to carbonic acid that the methane
PARAFFIN POLYHALIDES
95
trihalides do to formic acid,
carbonic acid :
They will, therefore, be treated after
CF4
Methane
Tetrafluoride.
CC14
Methane
TetracWoride.
CBr4
Methane
Tetrabromide.
CI4
Methane
Tetraiodide.
These compounds are also called methane perhalides, to indicate
that the hydrogen in them is completely replaced by halogens.
Polyhalide Ethanes. — The following table contains the boiling
points of the known polychlor- and polybrom-ethanes :
Name.
Formula.
M.P.
B.P.
Formula.
M.P.
B.P.
Vinyl Trichloride .
/Mrichlorethane .
Ethenyl Trichloride .
a-Trichlorethane .
Methyl Chloroform
CH2C1
CHC12
CC13
CH4
—
114°
74'5P
CHBr3
CH2Br
—
187-188°
sym.- Acetylene Tetrachlo-
CHC12
pprri
147°
CHBra
PWRr
__
102°
(12 mm.)
unsym.-AcetylideneTetra-
CC13
pTT pi
_
129°
CBr8
/^TT T>_
_
105°
(i V5 mm )
C£i2Jjr
Pentachlorethane . .
CC1,
CHC12
—
159°
CBr3
CHBr2
54°
decomposes
Perchlorethane ....
CC13
CC1,
187°
sublimes
CBr,
CBr3
—
decomposes
at 200-210°
without
melting.
For the relations existing between the boiling points and specific volumes of
the halogen substitution products of the ethanes, see B. 15, 2559. As to the
refractive power of the brominated ethanes, see Z. phys. Ch. 2, 236.
The polychlor- and polybrom-ethanes have few genetic relation-
ships with the oxygen compounds corresponding with them. The
methods of formation and the reactions of the polysubstituted ethanes
are most intimately related to the methods of formation and the
reactions of the halogen substitution products of the ethylenes and
acetylenes, a tabular view of which will be given in the following
section. They will, therefore, precede the discussion of the latter.
It may be merely mentioned here that by the action of chlorine on ethyl
chloride and ethylidene chloride in sunlight methyl chloroform or a-trichlor ethane,
CH3CC18, is produced, together with vinyl trichloride, CH2Cl.CHCla. The
further action of chlorine on the trichlorethanes produces CH2C1.CC13,
CHC12.CC18) and perchlorethane, Cas.CCl3. CHC12.CHC18 is formed from
acetylene dichloride and chlorine, as well as from dichloraldehyde by means of
phosphorus pentachloride (B. 15, 2563). Only methyl chloroform, CH3.CC18,
related to acetic acid in the same way as chloroform is to formic acid, will be
further described, together with the chlorides of the fatty acids. Acetylene
96 ORGANIC CHEMISTRY
tetrachloride, sym.-Tetrachlorethane, CHC12.CHC12 is prepared by the direct union
of acetylene and chlorine (p. 87). The gases combine quietly when they are
led separately into boiling water, or when sulphur chloride is alternately saturated
with chlorine and acetylene in presence of iron powder (C. 1905, I. 1585 ;
1096, II. 746).
Perchlorethane, C2C18, m.p. 187°; b.p. 776.7 185-5°, D=2-oi, results, together
with perchlorobenzene (Z. Electroch. 8, 165), from the direct union of carbon and
chlorine when an electric arc is struck in an atmosphere of chlorine. A good
yield is obtained when carbon tetrachloride is warnied with amalgamated alu-
minium (B. 38, 3058). It forms a crystalline mass, with a camphor-like odour.
It sublimes at the ordinary pressure, as its critical pressure lies below 760 mm.
When its vapours are conducted through a tube heated to redness it breaks
down into C12 and perchlorethylene. It yields the latter compound when it is
treated with potassium sulphide.
a-Tribromethane, CHs.CBr8, has not yet been prepared.
Acetylene Tetrabromide, CHBr2.CHBr2, is obtained from acetylene and bromine.
Zinc dust and alcohol convert it into acetylene dibromide (A. 221, 141), whilst
benzene and A1C13 change it into anthracene (q.v. Vol. II.).
Perbromethane, C2Brc, is obtained by the addition of bromine to acetylene
tetrabromide in the presence of aluminium bromide (C. 1898, I. 882). It is a
colourless, crystalline compound, dissolving with difficulty in alcohol and ether.
It breaks down at 200° into bromine and perbromethylene, CrBr4.
Five structural cases are possible for trisubstituted propane. The most
important of these derivatives have the structure CH2X.CHX.CHX2,
corresponding with glycerol, CH2(OH).CH(OH).CH2(OH). They will
be discussed after the latter.
Mixed Halogen Substitution Products of the Paraffins. — There are numerous
paraffins containing different halogens side by side in the same molecule.
B. HALOGEN DERIVATIVES OF THE OLEFINES
As a general rule, the halogen substitution products of the un-
saturated hydrocarbons cannot be prepared by direct action of the
halogens, since addition products are apt to result (p. 82). They are
produced, however, by the moderated action of alcoholic potassium
hydroxide (C. 1901, I. 816 ; II. 804), or Ag2O, on the disubstituted
hydrocarbons CnH2wX2. This reaction occurs very readily if the
addition products of the defines are employed :
C2H4Cl2 + KOH=C2H3Cl+KCl-fH2O.
Ethylene Monochlor-
Chloride. ethylene.
When the alcoholic potassium hydroxide acts very energetically,
the hydrocarbons of the acetylene series are formed (p. 86). Being
unsaturated compounds they unite directly with the halogens, and also
with the halogen acids :
CH2 CHaBr
II +Br2=|
CHBr CHBra
These reactions indicate that ethylene is the parent substance for the pre-
paration of nearly all the halogen-substituted ethanes and ethylenes, as well as
for the preparation of acetylene.
The following diagram represents how, by the addition of bromine and the
loss of hydrogen bromide, the bromine substitution derivatives of the ethanes
HALOGEN DERIVATIVES OF THE OLEFINES 97
are connected with ethylene, with the ethylene bromine derivatives and with
acetylene (A. 221, 156) :
CH3 = CH2
CHEE
CHBr=CHBr—
CHBr2.CHBr2 ~ 1>
CBrs.CBr,;
Vinyl Chloride, CH2=CHC1, and Vinyl Bromide, CHa=CHBr, are obtained
from ethylene chloride and ethylene bromide by the action of alcoholic potassium
hydroxide, which, by continued action on them, produces acetylene. The group
CHa =CH — is called vinyl. Vinyl chloride can also be obtained by heating ethy-
lene dichloride or ethylidene dichloride (B. 35, 3524).
The boiling points of the chlorinated and brominated ethylenes are given in the
following table :
Formula.
B.P.
Formula.
B.P.
Vinyl Chloride, Monochlor-
ethylene
CHa— CHC1
— 1 8°
CHa=CHBr
4-l6°
Acetylene Dichloride, sym.-
Dichlorethylene ....
Acetylidene Dichloride, un-
sym.-Dichlorethylene .
Trichlorethylene ....
Tetrachlorethylene, Perchlor-
CHC1=CHC1
CH2=CC12
CHC1=CC12
CC12— CCla
+55°
+37°
88°
121°
CHBr=CHBr
CH2=CBra
CHBr=CBr2
CBr2=CBr2
-flU
110°
91°
164°
M.P.
*;^°
Tetra-iodoethylene
(B. 26, R. 289 ; 30, 1200) .
CIa=CIa
Do
187°
Consult A. 221 , 1 56, for the relations between the boiling points of the bromethanes
and bromethylenes. The unsymmetrical compounds, CH2=CHC1, CH2=CHBr,
CH2=CCla and CH2=CBr2, polymerize quite easily (B 12, 2076). CH2=CBra
and CHBr = CBra yield CH2Br.COBr, bromacetyl bromide, and CHBra.COBr,
dibromacetyl bromide (B. 16, 2918 ; 21, 3356) with oxygen. Ozonized air con-
verts perchlorethylene into phosgene, COCla, and trichloracetyl chloride (B. 27,
R. 509 ; C. 1899, I. 588). Consult A. 235, 150, 299, for the action of A1C13 on
polybromethanes and ethylenes, in the presence of benzene.
Tetra-iodoethylene CI2 : CIa and Di-iodoethylene CHI : CHI, m.p. 73°, are formed
by the action of iodine and water on calcium carbide (B. 38, 237). Fluorethylene
(C. 1901, II. 804).
Three different mono-halogen products are derived from Propylene, CH8—CH
-CH2:
(i) CH3— CH=CHX
•-Derivatives.
(i) The a-derivatives
VOL. I.
(2) CH8— CX=CHa (3) CH2X— CH=CHt.
•y-Derivatives.
are
Derivatives.
obtained from the propylidene compounds,
93 ORGANIC CHEMISTRY
CH3.CH2.CHXa (from propyl aldehyde), when the latter are heated with alco-
holic potassium hydroxide.
(2) The ^derivatives, CH8.CX:CHa, are prepared in pure condition from
the halogen compounds, CH3.CXa.CH, (p. 93), derived from acetone.
(3) The y-derivatives of propylene, CH2X— CH=CH2, are de-
sienated AUyl halides, because they correspond with allyl alcohol,
CH2 : CH.CH2OH. They will be described after the alkylogens.
C. HALOGEN ACETYLENES
Acetylene Monoehloride, C2HC1, has been obtained from dichloracrylic acid,
CCla=CH.CO2H, by the action of aqueous barium hydroxide. It is an explo-
sive gas (A. 203, 88 ; B. 23, 3783)-
Acetylene Bromide, CaHBr, obtained from the dibromide by means of alcoholic
potassium hydroxide, is a gas, inflaming when in contact with the air.
Dibromacetylene, CaBr2,b.p.77°, D =2-0, can be prepared from tribromethylene
by means of alcoholic potassium hydroxide. It is spontaneously inflammable
(C. 1903, II. 53* ; 1901, I. 231.).
Acetylene Di-iodide, Calt, is produced when iodine acts on silver acetylide
or calcium carbide, or when iodine and hypochlorites of the alkali metals act on
acetylene (B. 37, 4415) ; also by boiling barium iodopropiolate with water
(A. 308, 326 ; B. 34, 2718). It possesses an odour like phenyliso cyanide. It
decomposes to a considerable extent into tetra-iodoethylene and carbon in the
light or when heated (B. 37, 3453)-
The halogen acetylene derivatives polymerize more easily than acetylene
itself. The products are in part benzene derivatives : monobromacetylene
yields tribromobenzene.
3CH=CBr=CflH3Br, ; 3CH=CI=C6H8I8.
Tribromobenzene. Tri-iodobenzene.
Allylene Iodide, CH8 • CI, b.p. 110°, is formed from silver allylene and iodine
solution (A. 308, 309).
Perchloromesole, C4C16=CC13.C=C.CC13(?) or CC12=CC1-CC1=CC12 (?), m.p.
39°, b.p. 284°, may be mentioned here. It frequently appears in exhaustive
chlorinations (B. 10, 804 ; comp. B. 22, 1269)
OXYGEN DERIVATIVES OF THE METHANE HYDROCARBONS
Acquaintance was made with the simplest linkings of the carbon
atoms when studying the aliphatic hydrocarbons and their halogen
substitution products. The derivatives next in order are the oxygen
compounds, which furnish further basis for the classification of the
carbon compounds. They may be considered as being derived from
the aliphatic hydrocarbons by the substitution of the univalent water
residue — the hydroxyl group — OH, for hydrogen.
But one of the several hydroxyl groups may become attached
to each carbon atom. In the first instance alcohols result, which are
neutral compounds, closely related in many respects to water. Alcohols,
according to the number of hydroxyl groups present in them, are
classified as mono-, di-, tri-, and poly-hydric, because in the alcohols
with one hydroxyl a univalent radical, and in those with two hydroxyls
a divalent radical, etc., is in union with the water residues. There-
fore the simplest monohydric alcohol contains one carbon atom, the
simplest dihydric alcohol two carbon atoms, etc., as indicated in the
following arrangement :
OXYGEN DERIVATIVES OF THE METHANE SERIES 99
CH4 CH3.OH Methyl Alcohol, the simplest monohydric alcohol.
CH8 CH2.OH
Ethylene Glycol, the simplest dihydric alcohol.
CH8 CH2.OH
CH$ CH2.OH
CH, CH.OH Glycerol, the simplest trihydric alcohol.
CH, CH2.OH
CH, CH2.OH
CHa CH.OH
Erythritol, the simplest tetrahydric alcohol.
CHa CH.OH
I I
CH3 CH2.OH
CH3 CH2.OH
I I
CHa CH.OH
CH. CH.OH Arabitol, the simplest pentahydric alcohol.
I I
CH2 CH.OH
I I
CH3 CH2.OH
CH, CH2.OH
I I
CH. CH.OH
I I
CH, CH.OH
Mannitol, the simplest hexahydric alcohol.
CH, CH.OH
CH, CH.OH
CH, CH2.OH
Or, hydrogen atoms attached to the same carbon atom of
hydrocarbons are replaced by —OH groups. In such cases, with
few exceptions, water splits off, and oxygen unites with its full
valence to carbon. The following possibilities then arise : two
hydroxyl groups replace two hydrogen atoms of a terminal CH3-group,
or of an intermediate CH2-group ; three hydroxyl groups replace
three hydrogen atoms of a terminal CH3 group ; in either case,
water always separates, e.g. :
(I) CH, COH _„ C<H CH, COH -H C<°
H H " H CH, CH, *" CH,
CH, CH, CH,
/I OH\ ~~H2O I
/_\ /^TT I /^ -X'^"' •""*• I /^ /%
CH> VC<OHj — > C^0
CH, CH, CH,
/ /* \ r^T^ / / \ PVU
(3) CH3 (C^OH j _H20 C<£H CH3 (C^OH\ -H8O C<gH
H H ^ H CH, CH, ' ^ CHt
ioo ORGANIC CHEMISTRY
Thus, three new classes of oxygen derivatives are formed :
(1) Compounds containing the group — C<H are ^nown as Alde-
hydes, where the group — C<^ is called the aldehyde group.
(2) Compounds containing the group =C=0 in union with two
carbon atoms are called Ketones. The group =CO is known as the
keto- or ketone group.
/~v TT
(3) Compounds containing the group — C<Q are named Car-
boxylic acids, in which the group — C<Q H is called carloxyl. The
alcohols, aldehydes, and ketones are neutral substances. The car-
boxylic acids are pronounced acids, and form salts in the same manner
as the mineral acids.
Aldehydes, ketones, and carboxylic acids are most intimately
related to the monohydric alcohols. They are the oxidation products
of alcohols, and will be discussed after them. Unsaturated hydro-
carbons (olefmes and acetylenes), in like manner, yield unsaturated
alcohols, aldehydes, ketones, and carboxylic acids. In the following
sections the unsaturated derivatives will receive attention after the
saturated compounds corresponding with them ; i.e. the unsaturated
alcohols will follow the saturated alcohols.
Similarly, an almost endless series of oxidation products are con-
nected with the di-, tri-, and poly-hydric alcohols. These contain
the same oxygen-containing atomic groups, as the monohydric alcohols
and their oxidation products, but possess several of them in the same
molecule. The multiplicity grows rapidly ; as will be seen later, nine
classes of oxidation products may be derived from the dihydric alcohols
or glycols alone.
Finally, when in methane, the four hydrogen atoms are replaced by hydroxyl
groups, the loss of two molecules of water would be possible, and carbon dioxide,
the anhydride of two acids incapable of free existence (orthocarbonic acid and
ordinary metacarbonic acid) would be obtained. The carbonates are derived from
the meta-acid.
,H
/H
C<H
.OH
/OH
/OH
C^-OH
x*O
C<OH
\OH
O
c\)
Orthocarbonic Acid.
Metacarbonic Acid.
Carbon Dioxide.
Methane.
The carbonates are salts of a dibasic acid. Therefore, carbonic
acid, with its numerous derivatives, will be discussed before the di-
carboxylic acids, the final oxidation products of the dihydric alcohols
or glycols, whose simplest representative is oxalic acid.
III. THE MONOHYDRIC ALCOHOLS AND THEIR OXIDATION
PRODUCTS
i. MONOHYDRIC ALCOHOLS
The monohydric alcohols can be looked upon as consisting of
water in which one hydrogen atom has been replaced by a monovalent
MONOHYDRIC ALCOHOLS 101
hydrocarbon residue. If both hydrogen atoms in water are so sub-
stituted, there result the ethers, which are at the same time alkyl oxides
or alcoholic anhydrides.
H\
H/
C«H
O H/ C,H
Ethyl Alcohol. Ethyl Ether.
The monohydric alcohols contain one hydroxyl group, OH ; bi-
valent oxygen links the univalent alcohol radical to hydrogen, as in
CH3.O.H, methyl alcohol. This hydrogen atom is characterized by
its ability, in the action of acids on alcohol, to be exchanged for
acid residues, forming compound ethers or esters, corresponding with
the salts of mineral acids :
C2HS.OH+NO2.OH=C2H6.O.N02+H2O
Ethyl Alcohol. Ethyl Nitrate or
Nitric Ethyl Ester.
Alkyls and metals can also replace the hydrogen in alcohol :
C2H,.O.CH, C2H6.ONa
Ethyl Methyl Ether. Sodium Ethoxide.
Structure of the Monohydric Alcohols. — The possible isomeric
alcohols may be readily derived from the hydrocarbons. There is one
possible structure for the first two members of the normal alcohols :
CH,.OH C2H5.OH
Methyl Alcohol. Ethyl Alcohol.
Two isomers can be obtained from propane, C3H8=CH3.CH2.CH3 :
CH3.CH2.CH2.OH and CH3.CH(OH).CH8
Propyl Alcohol. Isopropyl Alcohol.
Two isomers correspond with the formula C4H10 (p. 27) :
CH8.CH2.CH2.CH8 and CH(CH,),
Normal Butane. Isobutane.
Two isomeric alcohols may be obtained from each of these :
CH8 CH,
CH, CH,
and | /CH, /CH,
CH, CH.OH CH(-CH2.OH and C(OH)^CH,
I I XCHS NCH,
CH2.OH CH3
Primary Butyl Secondary Butyl Prim. Isobutyl Tert. Isobutyl
Alcohol. Alcohol. Alcohol. Alcohol.
An excellent method of formulating the alcohols was introduced by
Kolbe in 1860 (A. 113, 307 ; 132, 102). He regarded all alcohols as
derivatives of methyl alcohol, for which he proposed the name carbinol,
and compared the alcohols, formed by the replacement of hydrogen
not in union with oxygen by alcohol radicals, with the primary, second-
ary, and tertiary amines, resulting from the replacement of the
hydrogen in ammonia by alcohol radicals. With this view as a basis,
Kolbe predicted the existence of secondary and tertiary alcohols.
to* ORGANIC CHEMISTRY
Their first representative was discovered shortly afterwards. By the
replacement of one hydrogen atom in carbinol by alkyls (p. 43) the
primary alcohols result :
*» CH, I&*1" CaH
H '" CH,.OH
Methyl Carbinol, or Ethyl Carbinol or
Ethyl Alcohol. Propyl Alcohol.
If the replacing group possesses normal structure (p. 27), the primary
alcohols are said to be normal. In alcohols of this class the carbon
atom carrying the hydroxyl group has two additional hydrogen atoms
(they contain the group — CH2.OH). Hence compounds of this variety
may very easily pass into aldehydes (containing the CHO group) and
acids (with COOH group) on oxidation (see p. 100) :
CH, CH, CH,
yields and
CH2.OH COH COOH
Primary Alcohol. Aldehyde. Acid.
The secondary alcohols result when two hydrogen atoms in carbinol,
CH3.OH, are replaced by alkyls :
CH,
H
OH
CH.
CH.OH
CH,
C2H6
CH3
H
OH
CH.OH
CH3
Dimethyl Carbinol, or Ethyl Methyl Carbinol, or
Isopropyl Alcohol. Isobutyl Alcohol.
In alcohols of this class the carbon atom carrying the OH group
has but one additional hydrogen atom ; they contain the group
> CH.OH. They do not furnish corresponding aldehydes and acids,
but when oxidized, they pass into ketones (p. 100) :
IH
OH
yields
CH, CH,
CH, = >CO
O CH,
Dimethyl Carbinol. Acetone.
When, finally, all three hydrogen atoms in carbinol are replaced by
alkyls, there result the tertiary alcohols, containing the group /C.OH.
a = CH,-C.OH Trimethyl Carbinol.
* CH«
The tertiary alcohols decompose when oxidized.
The " Geneva names " for the alcohols are derived from the names of the corre-
sponding hydrocarbons, with the addition of the final syllable " ol " :
CH8.OH = [Methanol] ; CHs.CH2.OH = [Ethanol] :
CH,.CH,.CH,.OH = [i-Propanol] ; CH,.CHOH.CH, = [2-Propanol].
The parallelism between the formulae of the three classes of alcohols
MONOHYDRIC ALCOHOLS 103
and the three classes of amines (q.v.), is very evident upon studying
the following general formulae : —
R R\
R.CH-.OH £>CH.OH R-^C.OH
W
Primary Alcohols. Secondary Alcohols. Tertiary Alcohols.
T? R\
R.NHa R>NH RXN
Primary Amine. Secondary Amine. Tertiary Amine.
The behaviour of alcohols on oxidation is of great importance in
ascertaining whether a certain alcohol is primary, secondary, or
tertiary in character. What has already been stated may be sum-
marized thus :
A primary alcohol on oxidation yields an aldehyde, which passes
into a carboxylic acid if the action be continued. This acid contains
as many carbon atoms in its molecule as the parent alcohol. Oxidation
changes a secondary alcohol into a ketone, having an equal number of
carbon atoms in its molecule. A tertiary alcohol breaks down on
oxidation into compounds having a lower carbon content.
The basis of the classification of the next section is :
The monohydric alcohols and their oxidation products :
T
TO TO
(2) Aldehydes (-C<2). (3) Ketones (=CO).
io Q
(4) Carboxylic Acids (—G^Q _ H).
Four classes of oxygen derivatives must, therefore, be distinguished,
each containing saturated and unsaturated compounds.
Formation of Alcohols. — Summary of Reactions. — They are obtained
from bodies containing a like number of carbon atoms :
(1) By the saponification of acid esters.
(2) By the reduction of polyhydric alcohols.
(3) By the action of nitrous acid on amines.
(4) By the reduction of their oxidation products.
From nucleus-syntheses (p. 75) :
(5) By the action of magnesium alkyl halide or zinc alkyls, or
zinc and alkyl iodides, on aldehydes, acid chlorides, ketones, formic
esters, acetic esters, chlorinated ethers and ethylene oxide.
(la) From Haloid Esters or Alkylogens.—lt was mentioned, in
describing the reactions of the alkylogens, that the latter afford
a means of passing from the paraffins and olefines to the alcohols
(p. 93). As alkali hydroxide causes the separation of a halogen
acid from the alkylogens, it is possible to exchange hydroxyl for
the halogen, especially if this be iodine. This is most easily accom-
plished by the action of freshly precipitated, moist silver oxide, or by
heating with lead oxide and water :
C2H6I+AgOH=C2H6.OH+AgI.
104 ORGANIC CHEMISTRY
Thus, moist silver oxide behaves as a metallic hydroxide.
Even water alone causes a partial transposition of the more reactive tertiary
alkyl iodides ; the other alkylogens in general when heated for some time
with 10-15 volumes of water' to 100° are completely converted into alcohols
(A. 186, 390).
Tertiary alkyl iodides heated to 1 00° with methyl alcohol pass into alcohols
and methyl iodide (A. 220, 158).
(ib) By the Saponification of their Esters. — It is often more practical
first to convert the halogen derivatives into acetic acid esters, by heating
with silver or potassium acetate :
CaHBBr+C2H3O.OK=CaH8.O.C2H3
Potassium Acetate. Ethyl Acetic Ester.
and then to boil these with potassium or sodium hydroxide, to obtain
the alcohols :
C2H6.O.C2H3O+KOH=C,H6.OH+C2H3O.OK.
The second reaction is called saponification, because by means of it the soaps,
i.e. the alkali salts of the fatty acids and glycerol (q.v.), are obtained from the
glycerol esters of the fatty acids — the fats. More generally, this reaction is
known as hydrolysis : both terms are, unfortunately, employed somewhat
loosely (Tr.).
(ic) From Ethyl Sulphuric Acid by boiling water.
Ethyl Sulphuric Acid.
This reaction constitutes the transition from the defines to the
alcohols, as these esters may be easily obtained by directly combining
the unsaturated hydrocarbons with sulphuric acid.
Many alkylenes (like iso- and pseudo-butylene) dissolve at once in dilute nitric
acid, absorb water, and yield alcohols (A. 180, 245).
(2) The reduction of polyhydric alcohols by hydriodic acid yields the iodides of
secondary alcohols, which are converted by methods ia and ib into the alcohols
themselves, e.g. :
CHjOH CH, CH,
CH2OH CH, CH,
Glycerol. Isopropyl Isopropyl Alcohol.
Iodide.
Or, the chlorhydrins of the polyhydric alcohols may be reduced, e.g. s
CH» „,.,„ CH2OH aH CH2OH
-M — ^H
/"*TT /">1 V/X1»
U.rlsUl
Ethylene
Chlorhydrin.
(3) Action of nitrous acid on the primary amines :
C,HiNH,+NO.OH=C,H6.OH+N2+H2O.
In the case of the higher alkylamines transpositions often occur, and instead
of the primary alcohols, there result secondary alcohols (B. 16, 744).
(40) Primary alcohols result from the reduction of aldehydes, acid
chlorides, and acid anhydrides / also, by reduction of acid esters by
means of sodium and alcohol ; acid amides yield primary amines as
well as primary alcohols by this reaction (C. 1904, I. 577 ; II. 1697).
v^j,
L.
MONOHYDRIC ALCOHOLS 105
C2H6.HCO+2H=CH3.CH2.CH2.OH (Wiirtz, A. 123, 140),
Propyl Aldehyde.
CH3.COC1+4H=CH3.CH2.OH4-HC1.
Acetyl Chloride.
£53'™>O+4H==C2H,.OH-r-CH3.COOH (Linnemann, A. 148, 249).
U.tl3.UvJ
Acetic Anhydride.
C^|C°>O+4Na+2C6HJ1OH=CH3.CH2.ONa+3C5HllONa* (Bouveault and
Amyl Acetic Ester.
Blanc, C. 1904, II. 184 ; 1905, II. 1700).
Aldehydes are first formed in the reduction of acid chlorides and anhydrides ;
they in turn are reduced to alcohols. As reducing agents, dilute sulphuric acid
or acetic acid, together with sodium amalgam, sodium, iron filings, and zinc
dust may be employed (B. 9, 1312 ; 16, 1715).
The last of these reactions is that by which an alcohol can be converted into
another containing an atom more of carbon. The alcohol is changed through
the iodide to the cyanide, and the latter to the acid, which, by reduction of its
chloride or its aldehyde, yields the new alcohol :
CH,OH
The reduction of ketones yields secondary alcohols (Friedel, A.
124, 324), together with pinacones (q.v.), the di- tertiary dihydric
alcohols or glycols :
CH8 CH8 CH8 CH3 CH8
CO + 2H = CI-IOH; 2CO + 2H = HO— C C.OH
II I II
CH8 CH3 CH3 CH3 CH8
Acetone. Isopropyl Alcohol. Pinacone.
Nucleus- synthetic Methods of Formation.
(5«) Acid Chlorides and Zinc Alky Is ; Ketones, Zinc Alky Is and
Alkylogens. — A very remarkable synthetic method, proposed by
Butlerow (1864), which led to the discovery of the tertiary alcohols,
consists in the action of the zinc compounds of the alkyls on the
chlorides of the acid radicals (Z. Ch., 1864, 385 ; 1865, 614).
The reaction proceeds in three stages. At first only one molecule of zinc
alkyl reacts, and forms an addition compound with the acid chloride, as a result
of the breaking down of the double linkage between the carbon and oxygen :
^O /CH,
I. CH8.C\ +Zn(CH3)a=CH3C^-O.Zn.CH8.-
NC1 \C1
Acetyl Chloride.
By decomposing the reaction-product with water, acetone is formed. How-
ever, should a second molecule of the zinc alkyl act upon the new compound,
further reaction will take place on longer standing :
/CH3 /CH3 PI
II. CH8.C^O.Zn.CH3+Zn(CH3)2=CH8.C^O.Zn.CH3+Zn<;:;,
If water be now permitted to react, a tertiary alcohol will be formed :
xCFT CT-T
III. CH8.C^p.Zn.CH8+2H20=CH8.C^OH3+Zn(OH)2+CH4.
^CU3 \CH8
* Altered from German edition, according to original paper, Bull. soc. chim.
[3] 31, 672 (Tr.).
io6 ORGANIC CHEMISTRY
If, in the second stage, the zinc compound of another radical be employed,
the latter may be introduced, and in this manner we obtain tertiary alcohols
containing two or three different alkyl groups (A. 175, 374, and 188, no, 122 ;
C. 1910, II. 1201).
It is remarkable that only zinc methyl and zinc ethyl furnish tertiary alcohols,
whilst zinc propyl produces only those of the secondary type (B. 16, 2284 ; 24,
R. 667).
The ketones in general do not react with the zinc alkyls. On the other hand,
there are ketones which do not contain a CH8 group united to a CO group, such as
diethyl ketone (C2H6)2CO, dipropyl ketone (C,H7)aCO, and ethyl propyl ketone
C2H5.CO.C3H7, which are converted by zinc and methyl or ethyl iodide into
zinc alkyl compounds ; these, under the influence of water, pass into tertiary
alcohols (B. 19, 60 ; 21, R. 55). Unsaturated tertiary alcohols are obtained from
all the ketones by the action of zinc and allyl iodide (A. 196, 113).
(56) When zinc alkyls act upon aldehydes, only one alkyl group
enters the molecule, and the reaction-product of the first stage yields
a secondary alcohol when treated with water (A. 213, 369 ; and B. 14,
2557) :
CH8.CHO
Aldehyde. Methyl Ethyl Carbinol.
All aldehydes (even those with unsaturated alkyls, and also furfural) react in
this way — but only with zinc methyl and zinc ethyl, whilst with the higher zinc
alkyls the aldehydes undergo reduction to their corresponding alcohols (B. 17,
R. 318). With zinc methyl, chloral, CC12.CHO, yields trichlorisopropyl alcohol,
CC18.CH(OH).CH3 ; whereas with zinc ethyl it is only reduced to trichlorethyl
alcohol (A. 223, 162).
(5^) Just as tertiary alcohols are obtained from the acid radicals, so
secondary alcohols are derived from the esters of formic acid. Zinc
alkyls (or, better, alkyl iodides and zinc), are allowed to react in this
case, and two alkyls are introduced :
XXZn.CH. /OH
H - - - ~
O.C2H6
Ethyl Formic Ester.
Dimethyl Carbinol.
By using some other zinc alkyl in the second stage of the reaction, or by working
with a mixture of two alkyl iodides and zinc, two different alkyls may also be
introduced here (A. 175, 362, 374).
Zinc and allyl iodide (not ethyl iodide, however) react similarly with acetic
acid esters. Two alkyl groups are introduced and unsaturated tertiary alcohols
formed (A. 185, 175).
Chlorinated ethers, e.g. C1CH2.OCH3, and zinc alkyls yield ethers of primary
alcohols (B. 24, R. 858) :
2Cl.CH2.OCH8+Zn(CaH5)a=2C2H6.CH2.OCH8+ZnCl1.
(6) Alkyl magnesium halides react similarly to the zinc alkyls
with aldehydes and ketones. They are soluble in ether, are more
convenient to deal with and are generally more valuable. The alkyl
magnesium halides unite with aldehydes and ketones by breaking the
double oxygen bond, and subsequently give up the particular alcohol
on the addition of acidified water to the addition compound. Poly-
merized formaldehyde (trioxymethylene) gives rise to a primary
alcohol, the other aldehydes to secondary and the ketones to tertiary
alcohols (Grignard) :
MONOHYDRIC ALCOHOLS 107
CH3CH2MgBr ,/-O — MgBr ^"OH
CH20 - — > CH2 ^CH2
\CHjCH, \CH2CH,
CHgCHjMgl ^O — Mgl ^OH
CH,CHO - ~^CH3CH ^CH3CH
•^^ /-.TT /^TT ~-^ PTT /->TT
^"vUrl 2L/il 8 »^±i2v^rl8
CH,CII,MgI /O — Mgl /OH
(CH8)2CO - -^ (CH3)aC<( > (CH8)2C<(
XCH2CH8 XCH3CH3
By similar reactions formic acid esters yield secondary alcohols,
whilst alkyl carboxylic acid esters and carboxylic acid chlorides and
anhydrides give rise to tertiary alcohols :
CH8CH2MgI ^^OU2ii6
HCOOC2H, - — ^HC— OMgl
CH3CH Mgl
CH,COOC.H6 - — >CH3C— OMgl
In many reactions the tertiary alcohols which are first formed
lose water and so become converted into unsaturated hydrocarbons,
which may thus constitute the secondary or even the main product
of the reaction (C. 1901, I. 725 ; II. 622 ; 1902, I. 414).
Primary alcohols are also obtained by warming the addition-
products of ethylene oxide with the alkyl magnesium halides (C.
1903, II. 105 ; 1907, I. 1102) :
CHt\ /Br CHa— OMgBr CHa— OH
I >o.Mg< - M -- M
CH/ X^H, CH2— C2Hft CHa— C2Hg
(7) The action of sodium or barium alcoholates on alcohols of the
same name — especially among those of high molecular weight — leads
to the formation of monohydric alcohols possessing two or three times
the carbon content in the molecule (B. 34, 3246 ; C. 1902, I. 743).
For instance : amyl alcohol gives rise to a decyl alcohol of the con-
stitution isopropyl isoamyl ethyl alcohol.
(CH3)2.CH.CH.CH2OH (A ^ ^
(CH8)2.CH.CHrCH,
In addition to the above universal methods, alcohols are formed by
various other reactions. Their formation in the alcoholic fermenta-
tion of sugars in the presence of ferments is of great practical import-
ance. Appreciable quantities of methyl alcohol are produced in the
dry distillation of wood. Many alcohols, too, exist in combination
as already formed natural products in compounds, chiefly as compound
esters of organic acids.
io8 ORGANIC CHEMISTRY
Conversion of Primary into Secondary and Tertiary Alcohols. — By the elimina-
tion of water the primary alcohols become unsaturated hydrocarbons CnH2,,
(p. 82). The latter, treated with concentrated HI, yield iodides of secondary
alcoholic radicals, as iodine does not attach itself to the terminal but to the less
hydrogenized carbon atom (p. 84). Secondary alcohols result when these iodides
are acted on with silver oxide. The successive conversion is illustrated in the
following formulae :
CH.
CHa
CH2.OH CH,
Propyl Propylene.
Alcohol.
In a similar manner primary alcohols in which the group CH2.OH is joined to
a secondary radical, pass into tertiary alcohols :
(^"H" PT-T
H2.OH -> cH3>C=CHa ^CH
Isobutyl Alcohol. Isobutylene. Tertiary Butyl Tertiary Butyl
Iodide. Alcohol.
The change is better effected by the aid of sulphuric acid. The sulphuric
esters (p. 84), arising from the alkylenes, CnH2n, have the sulphuric acid residue
linked to the carbon atom with the least number of attached hydrogen atoms.
Physical Properties. — In physical properties alcohols exhibit a
gradation corresponding with their increase in molecular weight like
other bodies belonging to homologous series. The lower alcohols
are mobile liquids, dissolving readily in water, and possessing the
characteristic alcoholic odour and burning taste. As their carbon
contejtit increases, their solubility in water grows rapidly less. The
normal alcohols, containing from one to sixteen carbon atoms, are
fluid at the ordinary temperature, whilst the higher members are
crystalline solids, without odour or taste, resembling the fats. Their
boiling points increase gradually (with similar structure) in proportion
to the increase of their molecular weights, the rise being about 20°
for a difference of CH2. The primary alcohols boil higher than the
isomeric secondary, and the latter higher than the tertiary alcohols.
Here we observe again that the boiling points are lowered by an
accumulation of methyl groups (see p. 50).
The boiling points can be calculated with approximate accuracy
from the alkyl residues present (B. 20, 1948). The higher members
are only volatile without decomposition under diminished pressure.
Chemical Properties and Reactions. — The alcohols are neutral
compounds. In many respects the first members of the series resemble
water, and enter into combination with many salts, in which they
behave as alcohol of crystallization (p. no).
Some of the more important reactions are —
(1) The hydroxyl hydrogen is easily replaced by sodium, potassium,
and other metals, yielding thereby the alcoholates or alkoxides (p. 116).
(2) In their interaction with strong acids water separates and com
pound ethers or esters are produced. This reaction, in which the
alcohols figure as the base, is analogous to that taking place in the
formation of a salt from a basic hydroxide and an acid (p. 116).
MONOHYDRIC ALCOHOLS 109
(3) The haloid esters of the alcohols are produced when the alcohols
are heated together with the halogen acids. These esters are the
mono-halogen derivatives of the paraffins (p. 93). A more convenient
method for their formation consists in heating the alcohols with the
phosphorus halides (p. 93).
Nascent hydrogen, acting on these esters, affords a means of
reconverting the alcohols into their corresponding hydrocarbons
(P- 93).
(4) The primary saturated alcohols, on being passed over finely
divided metals (Cu, Ni, Zn, Al) heated to redness, are decomposed
into aldehydes. Similarly, secondary alcohols give rise to ketones,
and tertiary alcohols to olefmes (C. 1903, I. 1212 ; J. pr. Ch. [2]
67,420).
(5) Energetic dehydrating agents convert the alcohols, especially
those oi the tertiary class, into olefines (p. 82).
Reactions distinguishing Primary, Secondary, and Tertiary
Alcohols. — (i) In the preliminary description of the alcohols it was
clearly shown that primary alcohols, upon oxidation, yield aldehydes
and carboxylic acids ; that the secondary alcohols form ketones with
like carbon-content (p. 102), and that the tertiary alcohols break
down.
(2) If the alcohols be converted by phosphorus iodide (p. 93) into their
iodides, and the latter are changed by silver nitrite to nitroalkyls (p. 141), these
will show characteristic colour reactions, according as they contain a primary,
secondary, or tertiary alcohol radical.
(3) Acetic esters are formed when the primary and secondary alcohols are
heated with acetic acid to 155° C. The tertiary alcohols, under similar treatment,
lose water and form alkylenes (A. 190, 343 ; 197, 193 ; 220, 165)
(4) When the primary alcohols are heated with soda-lime they yield their
corresponding acids :
R.CH2.OH+NaOH=R.CO.ONa+2H2.
(5) PCI 3 reacts with the primary alcohols to form mainly esters of the type
Rp.PCl2 ; with secondary alcohols it produces unsaturated hydrocarbons, and
with tertiary alcohols the corresponding alkyl chlorides (C. 1897, II. 334).
(6) Primary and secondary alcohols yield the corresponding acetic acid esters
with acetyl chloride CH8COC1 ; the tertiary alcohols, on the contrary, give rise
to tertiary alkyl halides (C. 1906, II. 747).
A. SATURATED ALCOHOLS, PARAFFIN ALCOHOLS, C*H,n+,OH
The most important members of this series, and of the monohydric
alcohols in particular, are methyl alcohol or wood spirit, CH3.OH, and
ethyl alcohol or spirits of wine : CH3.CH2.OH.
i. Methyl Alcohol, Wood Spirit, Carbinol [Methanol\, CH3.OH,
b.p.760 66-67°, 1)20=0796, differs from all other primary alcohols in
that it contains the CH2OH group in union with hydrogen. Hence its
oxidation is not restricted to the corresponding monobasic carboxylic
acid, but may extend to carbonic acid :
VH
\H
no ORGANIC CHEMISTRY
. It is formed in large amounts in the dry distillation of wood. The
name methyl is derived from /xe'0u (wine), and v\rj (wood).
Physical Properties. — Methyl alcohol is a mobile liquid with
spirituous odour and burning taste. It mixes with water, alcohol,
and ether.
History. — Boyle discovered wood spirit in 1661 among the products of the
dry distillation of wood. In 1812 Taylor recognized it as being similar to spirits
of wine, but considered it an entirely different body. Dumas and Ptfigot (1831)
(A. 15, i) made the first study of it.
Methyl alcohol is also produced in the dry distillation of molasses.
It occurs in nature as methyl salicylic ester, C«H4{[2JOH°CH*' w^nter-
green oil, derived from Gaultheria procumbens / as the methyl ester of
anthranilic acid in neroli oil, in many alkaloids and other compounds.
The full synthesis of methyl alcohol proceeds from carbon disulphide
through methane and methyl chloride, by the action of aqueous
potassium hydroxide on the latter at 100° (Berthelot, 1858, A. chim.
phys. [3] 52, 101) :
KOH
CSa > CH4 > CH3C1 > CH8.OH.
The aqueous product obtained in the distillation of wood at 500° in iron
retorts contains methyl alcohol, acetone, acetic atid, methyl acetic ester, and
other compounds. It is distilled over quick-lime or soda, whereby the acetic
acid is held back in the form of a salt. Further purification is effected by means
of anhydrous calcium chloride, which combines with the alcohol to a crystalline
compound. This is removed, freed from acetone by filtration and drying, and
afterwards decomposed by distilling with water. Pure aqueous methyl alcohol
passes over, which is then dehydrated with lime or anhydrous potassium carbonate.
To procure it perfectly pure it is necessary to decompose oxalic methyl ester, a
readily crystallizable substance, the high-boiling methyl benzoate, or methyl
formic ester, with potassium hydroxide.
To detect ethyl alcohol in methyl alcohol, the liquid is heated with concentrated
sulphuric acid, when ethylene is formed from the ethyl alcohol, whilst methyl
ether results from the methyl alcohol. The amount of methyl alcohol in wood
spirit is determined, quantitatively, by converting it into methyl iodide, CH3I,
through the agency of PI3 (B. 9, 1928) ; the quantity of acetone is estimated
by the iodoform reaction (B. 13, 1000).
Uses. — Wood spirit is employed as a source of heat, and as a
denaturizing agent for ethyl alcohol. It is also used in making
varnishes, dimethyl aniline, and for the methylation of many carbon
derivatives, particularly the dye-stuffs. It is a good solvent for many
compounds of carbon.
Chemical Properties. — (i) Methyl alcohol combines directly with
CaCl2, to form CaCl2.4CH40, crystallizing in brilliant six-sided plates ;
homologous alcohols give similar compounds (C. 1906, II. 1715). Barium
oxide dissolves in methyl alcohol, forming the crystalline body
BaO.2CH4O. The alcohol in this salt behaves as alcohol of crystallization.
(2) Potassium and sodium dissolve in the anhydrous alcohol, to
form methylates, e.g. CH3OK and CH3ONa.
. (3) Oxidizing agents, e.g. air in presence of platinum black or
copper oxide, change methyl alcohol to formaldehyde, formic acid,
and carbon dioxide.
(4) Chlorine and bromine do not act so readily on methyl as
SATURATED ALCOHOLS, PARAFFIN ALCOHOLS in
on ethyl alcohol. Chlorine attacks aqueous methyl alcohol, however,
quite easily (B. 28, R. 771). Dichloromethyl ether, (C1CH2)2O, is
first produced which water converts into formaldehyde and hydro-
chloric acid (B. 26, 268).
(5) When methyl alcohol is heated with soda-lime, sodium formate
results with evolution of hydrogen :
CH,.OH +NaOH =CHO.ONa +2H,.
(6) When the alcohol is distilled over zinc dust, it breaks down into
carbon monoxide and water.
2. Ethyl Alcohol, Spirits of Wine [Ethanol],CH9CH.2OHtm.p. -112°
(B. 33, 638) b.p.760 78-3°, D0 = 0'8o6, D2p 0789. — In consequence of
its formation in the spirituous fermentation of saccharine plant juices,
alcohol, in impure state, was known to the ancients. It was, however,
only at the end of the eighteenth century that the knowledge of how
it might be obtained in an anhydrous condition was first acquired.
In 1808 Saussure determined its constitution.
Occurrence. — Ethyl alcohol seldom occurs in the vegetable kingdom. It is
found, together with ethyl butyrate, in the unripe seeds of Heracleum giganteum
and Heracleum spondylium. It is also present in the urine of diabetic patients.
It appears in that of healthy men after excessive consumption of alcoholic
beverages.
Formation. — It may be obtained by the general methods previously
described for primary alcohols : (i) From ethyl chloride ; (2) from
ethyl sulphate ; (3) from ethylene chlorhydrin ; (4) from ethylamine ;
(5) from aldehyde ; and (6) from acetyl chloride or acetic esters. The
synthesis of ethyl alcohol is, therefore, possible in two ways. The
first three methods show that it is genetically connected with acetylene,
ethylene, and ethane,whilst the last three methods indicate its relation to
acetylene just as acetic acid and its nitrile are genetically connected
with methyl alcohol. These relations are made clear in the following
diagram : —
CH, CH,C1
2C+H,
CHO
i
/
CH
C02H
1 <-—
CH,
CH4
CN
CH,
-»CH,C1 — •>
•CH,I
CHSOH
CH2NH,
CH
C-faS
ORGANIC CHEMISTRY
Starting with acetylene, the most direct course to ethyl alcohol would be
through acetaldehyde. Water converts it into the latter (p. 87), and nascent
hydrogen then reduces the aldehyde to alcohol.
If the acetylene be changed to ethylene, then various possibilities arise for the
formation of ethyl alcohol : (i) Ethylene and hydrogen unite to form ethane,
Which chlorine changes to ethyl chloride, yielding alcohol when heated with water.
(2) At 1 60° ethylene unites with sulphuric acid, forming ethyl sulphuric acid,
which boiling water changes to ethyl alcohol and sulphuric acid. In this manner
Berthelot first carried out the synthesis of ethyl acohol (C. 1899, I. 1018).
(3) Ethylene and hypochlorous acid yield ethylene chlorhydrin or mono-
chlorethyl alcohol which may be reduced to ethyl alcohol.
A nucleus-synthesis of ethyl alcohol from methyl alcohol is possible through
acetaldehyde. Methyl alcohol can be synthesized from carbon disulphicle
(p. no). Phosphorus iodide converts the methyl alcohol into methyl iodide,
and this, by action of potassium cyanide, is changed into methyl cyanide. Boiling
alkali transforms the latter into an alkali acetate, which phosphorus oxychloride
converts into acetyl chloride. The latter, by reduction, yields ethyl alcohol, with
acetaldehyde as an intermediate product. Acetaldehyde may also be prepared
from calcium acetate by heating it with calcium formate.
Preparation. — Ethyl alcohol is prepared on a technical scale almost
exclusively by what is termed the " alcoholic fermentation " of
saccharine liquids.
Scliwaan, in 1836, and independently Cagniard Latour, found that alcoholic
fermentation was brought about by yeast cells. This discovery, as opposed to
Liebig's mechanical fermentation theory (A. 29, 100 ; 30, 250, 363), only found
general acceptance from 1857 onwards, through Pasteur's investigations (A. chim.
phys. [3] 58, 323). In 1897 Buchner showed that the expressed liquid from
mechanically broken up yeast cells could also bring about alcoholic fermentation.
It is not yet settled whether the capacity for causing fermentation is due to the
presence of an enzyme-like body, zymase (enzyme theory), or whether it results
from the action of living protoplasm (plasma hypothesis (B. 32, 2086, 2372 ;
33, 971, 2764, with bibliography ; C. 1900, I. 1033 ; 1091, II. 700).
By " spirituous " or " alcoholic " fermentation is understood the breaking
down of certain kinds of sugar into alcohol and carbon dioxide by yeast, an
organized lerment, which consists of microscopic cells, about o'oi mm, in diameter,
and is known as saccharomyces cerevisiat seu yini,
Conditions of Alcoholic Fermentation.*— The yeast germs increase by
budding in dilute, warm (5-30°) sugar solutions : the growth is most
rapid at 20-30° C. Its development requires salts, especially phos-
phates, and albuminous substances, as well as oxygen at the commence-
ment (B. 29, 1983), but the fermentation proceeds afterwards without
access of air. When the quantity of alcohol in a fermenting liquid
reaches a certain amount, the fermentation ceases, since the yeast
germs cannot grow in liquids containing 14 per cent, of alcohol. They
are also destroyed by a temperature of 60°, and by small quantities of
phenol, salicylic acid, mercuric chloride, and other disinfectants.
The sugars occurring in ripening fruits — grapes, apples, cherries—
and in cane and beet, as well as in many other plants, belong to the
class of carbohydrates, which contain carbon, together with hydrogen
and oxygen in the same proportion in which they are present in water.
Ine carbohydrates will be discussed immediately after the hexahydric
alcohols : C6H8(OH)0— mannitol, dulcitol, sorbitol. etc., of which the
hrst oxidation products are the simple carbohydrates, C6H12O6.
'ever, so much relating to the carbohydrates will be given at this
time as appears necessary to understand alcoholic fermentation.
SATURATED ALCOHOLS, PARAFFIN ALCOHOLS 113
The carbohydrates may be arranged in three principal classes :
1. Glucoses or Monoses, C6H12O6 : dextrose, laevulose, etc.
2. Saccharobioses, C12H22On : maltose, sucrose, lactose, etc.
3. Poly saccharifies (C6H10O5)r : starch, dextrin, etc.
The carbohydrates of the second and third classes bear the relation
of anhydrides to the sugars of the first group.
The simple sugars of the formula C0H12O6 are capable of direct
alcoholic fermentation. This is particularly true of dextrose and
Icevulose, as well as of maltose among the saccharobioses. Technically,
it is of the greatest importance that those saccharobioses and the poly--
saccharides which are not directly fermentable, can be converted by
absorption of the elements of water into directly fermentable sugars.
Unorganized Ferments or Enzymes. — The breaking-down of saccharo-
bioses and polysaccharides by absorption of water (hydrolysis] is induced
by enzymes — albuminoid-like compounds, of which the most important
of this class are invertin and diastase.
Invertin is produced in the yeast germ. It is soluble in water and
has acquired its name from the fact that it is capable of convert-
ing sucrose into equimolecular quantities of dextrose and laevulose,
known as invert sugar. At the same time the rotatory power of the
liquid is reversed — it is inverted. Sucrose and dextrose are dextro-
rotatory, whereas laevulose deviates the plane of polarized light more
strongly towards the left than an equivalent quantity of dextrose
turns it to the right. Consequently, inversion changes a dextro-
rotatory sucrose solution into a laevo-rotatory solution of invert
sugar :
H,O
rose, Invertin
dextro-rotatory.
CflH j ,Oe — Dextrose, dextro-rotatory j invert
I Sugar,
I lasvo-
CeHiaO«— Lsevulose, Isevo-rotary J rotatory-
Diastase is another unorganized ferment, produced in the germina-
tion of barley and other grains. The germination of the so-called green
malt is stopped by killing the germ by rapid drying. The malt is
then subjected to kiln-drying at a temperature which will not in-
fluence the activity of the diastase which, at 50° to 60°, can hydrolyze
the starch. Two-thirds of the latter are changed to maltose, which
can be directly fermented by yeast, whilst one-third is converted
into dextrin, which is changed much more slowly by the diastase into
dextrose.
Maltose, like sucrose, belongs to the saccharobioses. It takes up
the elements of water and is resolved into dextrose. Lactose, also a
saccharobiose, in the same way passes into a mixture of equimolecular
quantities of galactose and dextrose. A review of these hydrolytic
relations is shown in the diagram (p. 114).
The hydrolysis of the saccharobioses and of starch may also be
brought about by warm, dilute sulphuric acid, whereby, for instance,
starch is converted into dextrose and dextrin. In technical operations
the preparation of saccharine juices from starchy compounds for the
purpose of fermentation is carried out almost exclusively by the
diastase of malt.
VOL. I. I
ORGANIC CHEMISTRY
CARBOHYDRATES.
GLUCOSES, MONOSES
C6HiaOe.
SACCHAROBIOSES
C12H2aOn.
POLYS ACCHARIDES
(C8H1006)x.
Dextrose -<
Dextrose -<
1 Maltose -<—
- Starch
Dextrose -<
Laevulose -<
Sucrose
Dextrose •<
Galactose -<
Lactose
Dextrose -<
Dextrin
According to Pasteur, 94 to 95 per cent, of sugar changes to alcohol
and carbon dioxide according to the equation :
CeHiaOa=2C2H6O+2COt.
Fusel oil, some glycerol (2-5 per cent.) and succinic acid (0*6 per cent.)
are formed simultaneously, although the latter two substances appear
generally towards the end of the fermentation (B. 27, R. 671). The
fusel oil contains n-propyl alcohol, isopropyl alcohol, isobutyl alcohol
(CH8)aCH.CHaOH, and especially amyl alcohol of fermentation — a mix-
true of isobutyl carbinol, ™»>CH.CH2.CH8OH, and optically active
methyl ethyl carbin carbinol, CH3'£**«>*CH.CHa.OH (p. 120).
Not only the varieties of Saccharomyces, but also other budding fungi, e.g.
Mucor mucedp, induce alcoholic fermentation. The various secondary fermen-
tations occasioned by Schizomycetes are remarkable. It appears that the fusel
oil (butyl and amyl alcohols) is produced by them in ordinary yeast fermentations.
Later views and experiments lead to the view that fusel oil, as well as succinic
acid, is not derived from the carbohydrates, but from the proteins (or their decom-
position products — aminocaproic acid, aminovaleric acid, aminoglutaric acid),
which arise partly from the material containing the sugar, and partly from
the added yeast (C. 1905, II. 156 ; B. 39, 3201). Alcoholic fermentation occurs
without the agency of organisms in undamaged ripe fruits (grapes and cherries),
when these are exposed for a period in an atmosphere of carbon dioxide.
Alcoholic Beverages. — The materials used in the preparation of alcoholic liquids
by means of fermentation are :
1 . Saccharine plant juices.
2. Starch-containing substances, seeds of grain and potatoes. The fermented
liquids are directly consumed (wine, beer) or they are first distilled in order to
produce the various kinds of spirits, the alcohol content of which may exceed
50 per cent. :
(i) By the fermentation of saccharine juices we obtain :
(a) without subsequent ck'stillation : (b) with subsequent distillation :
From grapes : wine. From wine : cognac,
apples : cider. ,, molasses : rum.
currants : currant wine, „ cherries : " kirschwasser "
etc. (Baden).
,, prunes : sliwowitz (Bohe-
mia), etc.
SATURATED ALCOHOLS, PARAFFIN ALCOHOLS 115
(2) By the fermentation of starch-containing substances, after converting
the starch into sugar with malt :
(a) withoi4t subsequent distillation :
Barley : beer.
Wheat : weissbier (Berlin).
Rice : sake (Japan).
(b) with subsequent distillation :
Barley and rye, wheat or oats, and
maize : corn whisky of various
kinds.
Rice : arrac (East India).
Potatoes : potato spirit.
Manufacture of Potato Spirit.* — Pure ethyl alcohol is obtained from potato
spirit. The potatoes are first heated with steam to 140-150° C. under a pressure
of from 2 to 3 atmospheres. The lower part of the apparatus is then opened and
the potato mash pressed out and digested at 57-60° in a mashing apparatus with
finely divided malt mixed with water. In this manner the starch of the potatoes
is converted into sugar. When the mash has cooled to the proper temperature
it is run into the fermentation-tubs, where it comes into contact with " pure cul-
ture " of yeast, and is then fermented. Crude spirit results from the distillation
of the fermented mash ; what remains is known as vinasse.
Manufacture of Pure Absolute Alcohol. — To purify the crude spirit further it
is fractionated on a large scale in the column apparatus of Savalle, Pistorius,
Ilges.^ The first portions, more readily volatile, contain aldehyde, acetal, and
other substances. A purer spirit (containing 95-96 per cent, of alcohol) follows,
and in commerce is known as spirit. Finally come the tailings, in which are the
fusel oils. To remove the latter, the spirit is diluted with water and passed through
previously ignited wood-charcoal, which retains the fusel oils, and the filtrate is
then distilled.
To prepare anhydrous alcohol, the rectified spirit (90-95 per cent, alcohol) is
distilled with anhydrous potassium carbonate, anhydrous copper sulphate,
quick-lime (A. 160, 249), or barium oxide. Commercial " absolute " alcohol
(about 99 per cent.) can be freed from its last traces of aldehyde and water, by
treatment with alkali and silver oxide, and subsequent distillation over metallic
calcium (B. 38, 3612). ^
Detection of Water in Alcohol. — Absolute alcohol dissolves barium oxide,
assuming a yellow colour at the same time, and does not restore the blue colour
to anhydrous copper sulphate. It is soluble without turbidity in a little benzene ;
when more than three per cent, of water is present, cloudiness ensues. On adding
anhydrous or absolute alcohol to a mixture of very little anthraquinone and some
sodium amalgam it becomes dark green in colour, but in the presence of traces of
water a red coloration appears (B. 10, 927). Aqueous alcohol generates acetylene
from calcium carbide, whilst the anhydrous spirit has no action in the cold (C.
1898, I. 658, 1225).
Detection of Alcohol. — Traces of alcohol in solutions arc detected and deter-
mined either by oxidation to aldehyde (q.v.) or by converting it by means of
dilute potassium hydroxide and iodine into iodoform (B. 13, 1002).
Its conversion into ethyl benzoate, by shaking with benzoyl chloride and
sodium hydroxide (B. 19, 3218 ; 21, 2744) also answers for this purpose.
Properties. — Absolutely pure alcohol is a mobile, colourless liquid
with an agreeable ethereal odour. At the temperature of liquid
air it is a thick liquid, and it solidifies to a varnish-like mass. It
burns with a non-luminous flame and absorbs water energetically
from the air. When mixed with water a contraction occurs, accom-
panied by rise of temperature ; the maximum is reached when
one molecule of alcohol is mixed with three molecules of water,
corresponding with the formula C2H6O-f 3H2O. The amount of alcohol
in aqueous solutions is given either in per cent, by weight (degrees
according to Richter) or per cent, by volume (degrees according to
Tralles). It may be determined by an alcoholometer, the scale of
* Ferd. Fischer : Hdb. d. chem. Technologic, 14. Aufl., 1893, S. 948.
f Ibid., 15. Aufl., 1902, 2 Bd. p. 353.
XI6 ORGANIC CHEMISTRY
which gives directly the per cent, by weight or volume for a definite
temperature (15° C.). Or the vapour tension is ascertained by
means of the vapourimeter of Geissler, or the boiling point is deter-
mined with the ebullioscope.
The alcohol contained in spirituous beverages is first distilled off
and then estimated in the distillate.*
Alcohol dissolves many mineral salts, the alkalies, hydrocarbons,
resins, fatty acids, and almost all the carbon derivatives. The majority
of gases are more readily soluble in it than in water ; 100 volumes of
alcohol dissolve 7 volumes of hydrogen, 25 volumes of oxygen, and 16
volumes of nitrogen.
Ethyl alcohol forms crystalline compounds with some salts, e.g.
calcium chloride and magnesium chloride, in which it behaves analo-
gously to water of crystallization.
Reactions. — Potassium and sodium dissolve in it, yielding the alco-
holates. With sulphuric acid it yields ethyl sulphuric acid, and with
sulphuric anhydride, carbyl sulphate (p. 83). Phosphorus bromide and
iodide change it into ethyl bromide and ethyl iodide. Being a primary
alcohol, such oxidants as manganese peroxide and sulphuric acid,
chromic acid, platinum black and air, convert it to acetaldehyde and
acetic acid (p. 102). Chlorine and bromine oxidize alcohol to acetalde-
hyde, which unites with more alcohol to form acetal. Chloral- and
bromal-alcoholates are derived from acetal. Bleaching powder changes
alcohol to chloroform, and iodine and potassium hyolroxide convert
it into iodoform. Nitric acid, free from nitrous acid, changes alcohol
into ethyl nitrate (q.v.}. Under certain conditions alcohol can be so
oxidized by nitric acid that, besides attacking the CH2.OH group,
the methyl group may be changed with the resulting formation of
glyoxal, glycollic acid, glyoxalic acid, and oxalic acid :
Ethyl Alcohol. Glyoxal. Glycollic Acid. Glyoxalic Acid. Oxalic Acid.
Mercury fulminate (q.v.) is produced when alcohol acts on mercury and
an excess of nitric acid. Boiling with mercuric oxide and sodium hydroxide
gives rise to a basic, explosive body, C2Hg6O4Ha, called mercarbide (B. 33, 1328).
If alcohol be passed through a red-hot tube, decomposition will be found to
begin at 800°, and at 802-830°, about J of it splits up into ethylene and water,
and $ into aldehyde and hydrogen, whilst § of the aldehyde further breaks down
into methane and carbon monoxide (B. 34, 3579). These decomposition products
appear at lower temperatures by passing alcohol vapour over finely divided
metals or aluminium oxide (C. 1903, I. 955 : II. 335).
Alcoholates. — Sodium ethoxide is the most important alcoholate, as it is
employed in a series of nucleus-synthetic reactions. It affords a means of splitting
ofiE water and alcohol. It may be prepared by dissolving sodium in alcohol,
then heating it to 200° C. in an atmosphere of hydrogen to free it from alcohol, when
it forms a white, voluminous powder (A. 202, 294 ; B. 22, 1010). Or, a calculated
quantity of metallic sodium is added to a solution of alcohol in ether, toluene,
* Post : Chemisch-technische Analyse, Braunschweig, 1881 ; Bockmann,
Chem.-tech. Untersuchungsmethoden, Berlin, 1888 ; Kbnig : Chemie der mensch-
lichen Nahrungs und Genussmittel ; Eisner : Die Praxis des Chemikers bei Unter-
suchung von Nahrungsmitteln, etc., 1893.
I
SATURATED ALCOHOLS, PARAFFIN ALCOHOLS 117
or xylene, and the whole is heated under a reflux condenser until the sodium
has entirely disappeared (B. 24, 649 ; 37, 2067). An excess of water changes
the alcoholates to alcohol and sodium hydroxide ; with a small amount of water
the reaction is incomplete. The alcoholates also result on dissolving KOH
and NaOH in strong alcohol. Sodium peroxide converts alcohol into sodium
alcoholate and sodium hydrodioxide, NaO.OH (B. 27, 2299).
Calcium Ethoxide, Ca(OC2H,)2, is formed by the solution of metallic calcium
in alcohol, or by the decomposition of calcium carbide by absolute alcohol with
the aid of heat (B. 28, R. 61 ; 38, 3614).
Aluminium Ethoxide, Al(OC2Hg)3, m.p. 134° ; b.p.14 205° ; Aluminium Propylate
A1(OC8H7)3, m.p. 106°, b.p.14 248°. are remarkable in that they are volatile without
decomposition under much reduced pressure. Aluminium Methoxide is decomposed
by heat under reduced pressure. These compounds are prepared by the action
of the respective alcohols on amalgamated aluminium (C. 1900, I. 10, 585).
Substituted Ethyl Alcohols :
1. CHtCl.CH,OH Glycol Chlorhydrin (Bromhydrin, lodohydrin).
2. CHClt.CHaOH Dichlorethyl Alcohol, b.p. 146° (B. 20, R. 363).
3. CCr,.CH8OH Trichlorethyl Alcohol, m.p. 18° ; b.p. 151° (A. 210, 63).
4. CH2NO2.CH2OH Nitroethyl Alcohol.
5. CH2.NH2.CH2OH Hydroxethylamine \ . ., ., , A1 , ,
6. CHS.CH(NH2)OH Aldehyde Ammonia] Amidoethyl Alcohols.
The compounds i, 4, and 5 will be discussed together with ethylene glycol,
and 6 with acetaldehyde. Di- and trichlorethyl alcohols have been prepared
by the interaction of zinc ethyl and di- and trichloracetaldehyde (p. iot>), whilst
trichlorethyl alcohol is formed from urochloralic acid (q.v.). The connection
between the chlorinated ethyl alcohols and their oxygen compounds, whose
chlorides they may be assumed to be, is seen in the following tabulation : —
Monochlorethyl Alcohol, CH2C1.CH2OH, corresponds with CHa.OH.CH2OH—
Glycol.
Dichlorethyl Alcohol, CHCla.CH2OH, corresponds with CHO.CH,OH— Glycolyl
Aldehyde.
Trichlorethyl Alcohol, CCl8.CHaOH, corresponds with COOH.CH , OH— Gly collie
Acid.
3. Propyl Alcohols [Propanols], C3H7.OH. — As explained in the
introduction to the monohydric alcohols, two isomeric propyl alcohols
are theoretically possible : the primary normal propyl alcohol and the
secondary isopropyl alcohol. Their constitution is evident from their
methods of formation and their reactions (p. 101).
Normal propyl alcohol, CH3.CH2.CH2.OH, b.p. 974° ; D20 = 0-8044.
Isopropyl alcohol, CH3.CH(OH).CH3, b.p. 827° ; D20 = 07887.
Normal Propyl Alcohol occurs in fusel oil (Chancel, 1853) from
which it is obtained by fractional distillation. It is an agreeable-
smelling liquid, which is miscible in every proportion with water, but
is insoluble in a saturated, cold calcium chloride solution, whereby it
can be distinguished from ethyl alcohol. It can also be prepared from
ethyl magnesium chloride and trioxymethylene (p. 106), and by reduc-
tion of propyl aldehyde. Oxidation converts it first to propyl alde-
hyde, and finally to propionic acid. By sulphuric acid it is converted
into propylene, and by hydriodic acid into isopropyl iodide. This
body is used for the preparation of isopropyl alcohol (p. 108),
which can also be obtained by the reduction of its oxidation product,
acetone.
Secondary or Isopropyl Alcohol, Dimethyl Carbinol, was prepared
in 1855 by Berthelot from propylene and sulphuric acid (p. 104),
n8
ORGANIC CHEMISTRY
and in 1862 by Friedel, from acetone. Kolbe (Z. Ch., 1862, 687)
recognized in isopropyl alcohol the first representative of the class of
secondary alcohols predicted by him (p. 101).
CH8.CH
It maybe obtained from propylene oxide, | >O, by reduction; from
CH2
formic ester by the aid of zinc and methyl iodide, and from acetaldehyde by means
of methyl magnesium iodide (p. 106). Its formation from normal propylamine
by the action of nitrous acid is noteworthy, and is accompanied by the simul-
taneous production of primary propyl alcohol and propylene.
The most practical method of obtaining it is to boil the iodide, which is easily
prepared from glycerol, with ten parts of water and freshly prepared lead hydroxide
in a vessel connected with a reflux condenser, or by simply heating the iodide
with twenty volumes of water to 100° (A. 186, 391). Oxidation changes it into
acetone, whilst chlorine converts it into unsymmetric tetrachloracetone (<7.v.).
m
Trichlorisopropyl Alcohol, £g3>CH.OH, m.p. 49°, b.p. about 153°, is pro-
duced by the action of zinc methyl on chloral (p. 106) (A. 210, 78).
4. Butyl Alcohols, C4H0.OH. — According to theory four isomerides are
possible : 2 primary, i secondary, and I tertiary (p. 101) :
Name.
Formula.
M.P.
B.P.
Sp. Gr.
i. Normal Butyl Alcohol
2. Isobutyl Alcohol .
3. Secondary Butyl Alco-
hol
CH3(CH2)2CH2OH
(CH8)2.CH.CHaOH
Liquid
M
116-8°
108-4°
99°
0-8099 at 20°
0-8020 at 20°
0-8270 at o°
4. Tertiary Butyl Alcohol
(CH3)3C.OH
25°
83°
0-7788 at 30°
Normal Butyl Alcohol, n-Propyl Carbinol [i-Butanol], is formed in the
action of sodium amalgam on normal butyl aldehyde (Method 40, p. 104),
and from ethylene oxide and ethyl magnesium bromide (Method 6, p. 106). It
is further produced by the fermentation of glycerol by a schizomyoetes together
with trimethylene glycol CH2[OH].CH8CH2[OH] (Fitz, B. 16, 1438 ; 29, R. 72).
Trlchlorobutyl Alcohol, CH3.CHCl.CCla.CHa.OH, m.p. 62°; b.p.45 120°, results
when zinc ethyl and butyl chloral (p. 106) are brought together, and is also
obtained from urobutylchloralic acid (A. 213, 372).
Secondary Butyl Alcohol, Methyl Ethyl Carbinol, Butylene Hydrate, [2-Butanol],
is a strongly-smelling liquid. It is obtained from methyl ethyl ketone by
reduction with sodium and water under ether (C. 1901, II. 1113) ; also
from normal butyl alcohol by conversion into butylene — with the loss of
water, — the addition of hydrogen iodide, and finally the hydrolysis of the
iodide produced (p. 108). The same iodide is formed on heating erythritol
CHaOH[CHOH]aCH2OH with hydriodic acid. Heated to 140-250°, it decom-
poses into water and /3-butylene/CH3.CH:CH.CH2.
The genetic relations existing between the normal primary and secondary
butyl alcohols, as well as between a-butylene and fl-butylene, are shown in the
following arrangement : —
CHaOH
CH,
{.H,
CH, CH
Secondary butyl alcohol is the simplest racemic alcohol (comp. p. 55). It is
resolved into its optically active components by means of the brucine salt of its
SATURATED ALCOHOLS, PARAFFIN ALCOHOLS 119
acid sulphuric ester ; but so far the two antipodes have not been obtained pure
(B. 40, 695).
Isobutyl Alcohol, Isopropyl Carbinol, Butyl Alcohol of Fomentation
[Methyl-2-propane-i-ol], occurs in fusel oils and especially in the
spirit from potatoes. It is a liquid possessing a characteristic odour.
It may readily be changed to isobutylene (CH3)2C=CH2, from which,
by the addition of halogen acids, derivatives of tertiary butyl
alcohol are obtained (p. 82). For the action of chlorine on isobutyl
alcohol see B. 27, R. 507 ; 29, R. 922.
Tertiary Butyl Alcohol, Trimethyl Carbinol, [Dimethyl-ethanot], was prepared
by Butlerow (A. 144, i) in 1863, from acetyl chloride and zinc methyl, and was
the first representative of the tertiary alcohols predicted by Kolbe.
The oxidation of tertiary butyl alcohol produces isobutyric acid (CH8)a.CH.CO aH
corresponding with isobutyl alcohol. This behaviour may be explained by the
intermediate formation of isobutylene (CH3)2C=CH8, the conversion of this,
by water absorption, into isobutyl alcohol, and the oxidation of the latter (A. 180,
73). The isobutylene, resulting from isobutyl alcohol and tertiary butyl alcohol,
by the withdrawal of water can, by the addition of HC1O and reduction of the
resulting chlorhydrin, be changed to isobutyl alcohol, and by absorption of HI
may be made to yield tertiary butyl iodide, which in turn may be trans-
formed into tertiary alcohol (p. 108).
The boiling points of the haloid esters of the butyl alcohols will be given with
those of the alkyl halides (p. 134).
Amyl Alcohols, C5Hn.OH. — Theoretically, 8 isomers are pos-
sible : 4 primary alcohols, 3 secondary, and I tertiary, all of which
are known.
The following table contains the formulae and the boiling points of
the eight amyl alcohols. The name amyl alcohol is derived from
a/xvAov=starch, because the first-discovered amyl alcohol was observed
in the fusel oil obtained from potato spirit.
Name.
Formula.
M.P.
B.P....
I. Normal Amyl Alcohol
2. Isobutyl Carbinol ....
CH3.[CH2]3CH2.OH
(CH3)2.CHCHa.CH2OH
g?
3. Active 1-Amyl Alcohol . . .
4. Tertiary Butyl Carbinol . .
(CH3),C.CHaOH
+ 49°
128°
112°
). Diethyl Carbinol ....
6. Methyl n-Propyl Carbinol
(CH3CH2)2CH.OH
CH8.CH2.CH3>CH-OH
116°
118°
7. Methyl Isopropyl Carbinol .
(CH,),cg3>CH-OH
112°
8. Dimethyl Ethyl Carbinol . .
J^XOH
-12°
I02'5°
Three of these eight alcohols contain an asymmetric carbon atom, indicated
in the formulae by a star, hence each can have three modifications, two optically
active and one optically inactive (p. 31), which raises the possible number of amyl
120 ORGANIC CHEMISTRY
alcohols to fourteen. On the connection between boiling point and velocity
of reaction, see B. 30, 2784.
(i) Normal Amyl Alcohol is most easily prepared from normal amylamme
which, in turn, is obtained from caproic acid. It is almost insoluble in water,
and has an odour of fusel oil.
(2) Isobutyl Carbinol, (CH3)2CH.CH2.CH2OH, constitutes the
chief ingredient of the amyl alcohol of fermentation obtained from
fusel oil (p. 114), and occurs as esters of angelic and crotonic acids
in Roman camomile oil. It may be obtained in a pure condition by
synthesis from isobutyl alcohol, which it approaches in structure and
with which it occurs in fusel oil :
CHrCOjH CHa.CHO CH,.CH,OH
CH ^CH
A A
CH,CH, CH3CH8
A simpler synthesis is that from isobutyl magnesium bromide and
trioxymethylene (Method 6, p. 106) (C. 1904, II. 1599). The so-called
alcohol of fermentation, b.p. 129-132°, occurs in fusel oil and consists
mainly of inactive isobutyl carbinol. It possesses a disagreeable
odour. In addition, 1- methyl ethyl car bin carbinol is present. It
rotates the plane of polarization to the left, the activity being due to
the presence of active amyl alcohol.
The different solubilities and crystalline forms of the barium salts of the
two alcohols distinguish them and assist in their separation. From the more
sparingly soluble salt, which forms in rather large quantity, isobutyl carbinol
may be obtained (Pasteur). A more complete separation of the alcohols is
reached by conducting HC1 into the mixture ; isobutyl carbinol will be esterified
first, the active amyl alcohol remaining unchanged (Le Bel) (A. 220, 149). A
more suitable substance for separating the fermentation amyl alcohols by the
esterification method is nitrophthallic acid (Vol. II.) (Markwald, B. 34, 479 ;
37, 1038). Oxidation of isobutyl carbinol gives inactive valeric acid, whilst
1-methyl ethyl carbin carbinol yields the active form. When the crude fermenta-
tion alcohol is distilled with zinc chloride, ordinary amylene is the product, which
consists mainly of (CH3)aC:CH.CH3, resulting from a transposition of isobutyl
carbinol ; it contains, besides, y-amylene and a-amylene (p. 85).
CH8\ ^
(3) Active Amyl Alcohol, >CH.CH2OH, sec.-Butyl Carbinol, Methyl
CH8CH/
Ethyl Carbin Carbinol. Of the two active modifications, the laevo-rotatory form,
not yet obtained pure, is the optically active constituent of the fermentation
alcohol. The proportion of the optically active alcohol in fermentation amyl
alcohol varies from 13 to 58 per cent., according to the origin of the latter (B. 35,
1596). Its rotatory power is [a]D = — 5-9°. The chloride, bromide, iodide, car-
bamic acid ester, and methyl ethyl acetic acid (see valeric acid) prepared from
the laevo-carbinol, are all optically active and indeed dextro-rotatory, whilst the
corresponding amine (p. 165) is laevo-rotatory (B. 28, R. 410 ; 29, 59).
The inactive modification of secondary butyl carbinol can be obtained by
heating with sodium hydroxide (Le Bel), and also synthetically from secondary
butyl magnesium bromide and trioxymethylene (p. 106 ; C. 1906, I. 130). Re-
solution by means of a mucor leaves the dextro-sec.-butyl carbinol (B. 15,
(4) Tertiary Butyl Carbinol, (CH3)3.C.CHZOH, is formed on reducing the
ilonde of trimethyl acetic acid or pivalic acid (B. 24, R. 557) with sodium
amalgam. Nitrous acid converts its amine, in consequence of a remarkable
rearrangement of atoms, into dimethyl ethyl carbinol (B. 24, 2161).
SATURATED ALCOHOLS, PARAFFIN ALCOHOLS 121
(5) Diethyl Carbinol, (C2H6)2.CHOH, is formed by the action of zinc and
ethyl iodide upon ethyl formate. Since j8-amylene, C2H5.CH:CH.CH3, yields
the iodide of methyl n-propyl carbinol with HI, from which methyl normal
propyl carbinol is obtained, the diethyl carbinol can thus be converted into the
latter alcohol :
CH8 CH, CH, CHa CH,
I I I I I
CH2 CH2 CH CHI CH.OH
CH.OH CHI CH CH2 CH,
C2H, C2H6 C2H5 C2H8 C2H,
/3-Isoamylene.
The two methyl propyl carbinols are obtained from methyl-n-propyl ketone
and methyl isopropyl ketone by reduction with sodium amalgam.
(6) Methyl n-Propyl Carbinol, CH3.CH2.CH2.CH(OH).CH3, is resolved by
Penicillium glaucum (Le Bel) ; the dextro-rotatory modification is destroyed,
and the laevo-rotatory form remains.
(7) Methyl Isopropyl Carbinol, (CH3)2.CH.CH(OH).CH3, yields the derivatives
of tertiary amyl alcohol, apparently with the intermediate formation of amylene,
(CH8)2C=CHCHa, when acted on by halogen acids and also PClft :
CH, CH, CH,
CH(OH) /CH\ CH,
I Mil ) H
CH V; / CC1
A A A
CH3CH8 CH3CH, CH3CH,
The true derivatives of methyl isopropyl carbinol are obtained from a-isoamyl-
ene (CH3)2.CH.CH:CHa (p. 185), by the addition of halogen acids, at ordinary
temperatures or when warmed.
(8) Tertiary Amyl Alcohol, ^^f>C.OH, Dimethyl Ethyl Carbinol, Amylene
Hydrate, is a liquid with an odour like that of camphor. It produces sleep, the
same as does chloral hydrate, and is, therefore, produced technically.
Amyl alcohol of fermentation is employed as the parent substance, which,
with zinc chloride, yields ordinary amylene, consisting mainly of /Msoamylene,
CH3CH=C<^8 (p. 185). This is shaken at —20° with sulphuric acid diluted
with $-1 volume of water, and the solution is boiled with water (A. 190, 345).
It is further formed by the action of nitrous acid on the amine of tertiary butyl
carbinol (B. 24, 2519), and from propionyl chloride and zinc methyl. At 200°
it decomposes into water and /?-isoamylene.
HIGHER HOMOLOGUES OF THE SATURATED ALCOHOLS, CnH2^+1.OH
There are many representatives of the higher homologues of the
alcohols of this series. Fourteen of the seventeen theoretically possible
hexyl alcohols and thirteen of the thirty-eight predicted heptyl alcohols
have been prepared. The higher we ascend in the series, the larger
the number of theoretically possible members and the smaller the
number of those alcohols which are actually known. Only a few of
them are noteworthy either from a point of formation, structure, or
occurrence in the animal or vegetable kingdoms. In the following
122
ORGANIC CHEMISTRY
table will be found the names, formulae, melting points, and boiling
points mainly of normal alcohols : —
Name.
Formula.
M.P.
B.P.
n-Hexyl Alcoliol
CH3.[CH2]4CH2.OH
I57°
Pinacolyl Alcohol
(CH3)3C.CH(CH3 OH
+ 4°
120°
Sym.-Tetrametliyl Ethyl Alcohol .
(CH^CH.qCH^OH
-10-5°
119°
CH3[CH2]6CH2OH
175°
Pentamethyl Ethyl Alcohol
(CH3)3C.C(CH8)3OH
+ 17°
131°
n-Octyl Alcohol
CH3.[CH2]6.CH2OH
199°
Cetyl Alcohol or Ethal ....
Ceryl Alcohol or Cerotin . . .
Melissyl or Myricyl Alcohol
CH3[CH2]14.CHaOH
C26H83.OH
C30H61.OH
4-49-5°
79°
85°
340°
n-Hexyl Alcohol occurs as acetic and butyric esters in the oil of the seed of
Heracleum giganteum (A. 163, 193).
Pinacolyl Alcohol has a camphor-like odour. It results from the reduction of
pinacolin (q.v.) or tert.-butyl methyl ketone, (CH3)3.C.CO.CH8. (See B. 26,
R. 14; C. 1901, II. 1157; comp. Tetramethyl Ethylene.) The isomeric sym.-
Tetramethyl Ethyl Alcohol is prepared from acetone and isopropyl magnesium
bromide. It decomposes when heated with dilute sulphuric acid into H8O and
tetramethyl ethylene (C. 1906, II. 1718).
n-Heptyl Alcohol has been prepared from cenanthol (q.v.) by reduction, and
from n-heptane (A. 161, 278). Pentamethyl Ethyl Alcohol has been obtained by
various syntheses by means of magnesium-organic compounds (C. 1906, II. 1718).
n-Octyl Alcohol, C8H17OH, occurs asacetic ester in the volatile oil of Heracleum
spondylium, as butyric ester in the oil of Pastinaca sativa, and in the oil of Hera-
cleum giganteum (A. 185, 26). It has been obtained artificially by several methods,
amongst others by the reduction of caprylic ester by sodium and alcohol (Method
4a, p. 104).
Cetyl Alcohol, Hexadecyl Alcohol, Ethal t C16H33.OH, is a white,
crystalline mass. It was prepared in 1818 by Chevreul from the
cetyl ester of palmitic acid, the chief ingredient of spermaceti (see
palmitic acid), by saponification with alcoholic potassium hydroxide :
Potassium
Palmitate.
1683 Cetyl
Alcohol.
When fused with potassium hydroxide, it yields palmitic acid
(p. 109) :
C16H81CH2OH + KOH =C, 5H81COOK +2Hr
Ceryl Alcohol, Cerotin, C26H63.OH, as ceryl cerotic ester, C28H61O.OCa,Hf,
(B. 30, 1418), constitutes Chinese wax. It is obtained by melting the latter
with potassium hydroxide, the prolonged action of which produces cerotic
acid.
Melissyl Alcohol, Myricyl Alcohol, C80H61.OH, occurs as myricyl palmitate
in beeswax, from which it is isolated in the same manner as the preceding com-
rxnmd. Chloride, m.p. 64°; iodide, m.p. 69*5°. Myricyl iodide and metallic
sodium give Hexacontane, CaoHm, or Dimyricyl (p. 76).
UNSATURATED ALCOHOLS 123
B. UNSATURATED ALCOHOLS
I. OLEFINE ALCOHOLS, C^H^.j.OH
These are derived from the unsaturated alkylenes, CnH2n, in the
same manner as the normal alcohols are obtained from their hydro-
carbons. In addition to the general character of alcohols, they possess
the property of the defines to form addition compounds.
The chief representative of the class is allyl alcohol, CH2—
CHCH2OH. When oxidized by potassium permanganate, the double
linkage of the allyl alcohols is severed, and trihydric alcohols — glycerols
—result (B. 21, 3347).
1. Vinyl Alcohol, Vinol, CHa:CH.OH, separates as a mercury oxychloride
compound, C2HjO2Hg3Cl,, from ethyl ether — a small quantity of which is always
retained — on the addition to it of an alkaline mercury monoxychloride solution
(Poleck and Thummel, B. 22, 2863). It is produced simultaneously with hydrogen
peroxide when ether is oxidized with atmospheric oxygen. It cannot be separated
from its mercury derivative because all reactions by which it should be pro-
duced yield the isomeric acetaldehyde, CH8.CHO (p. 37). It seems to be the
universal rule that the atomic grouping =C:CH. OH, in the act of formation, is
transposed into=CH.CHO (Erlenmeyer, Sr., B. 13, 309 ; 14, 320) ; however,
there are stable compounds in which the groupings =C=CHOH and=C=C(OH)R
(see Hydroxy-methylene Ketone, p. 343) are present.
The haloid esters of vinyl alcohol are to be considered as being the mono-
halogen substitution products of ethylene (p. 97). Vinyl ether, vinyl ethyl
ether, vinyl sulphide, vinyl or ethylene sulphuric acids, are known (p. 147).
The radical vinyl is present in neurine, so important physiologically, and also in
vegetable alkaloids (q.v.).
2. Allyl Alcohol [Propenol-fi, C3H5.OH = CH2 : CH.CH2.OH.—
Solidifies —50°, b.p. 96-97°, D20 = 0-8540. Allyl compounds occur in
the vegetable kingdom : allyl sulphide and diallyl trisulphide (C. 1892,
II. 833), in oil of garlic, and allyl thiocyanate, C3H5N=C=S, in
oil of mustard. It may be prepared (i) by heating allyl iodide — which
is easily prepared from glycerol — to 100° with 20 parts water ; (2) it
is produced, also, when nascent hydrogen acts on acrolei'n,
CH2:CH.COH, and (3) sodium on dichlorhydrin, CH2C1.CHC1.CH2OH
(B. 24, 2670). (4) It is best obtained from glycerol by heating the
latter with formic or oxalic acid (A. 167, 222).
In this reaction the oxalic acid at first breaks down into carbon dioxide and
formic acid, which forms an ester with the glycerol ; this then decomposes into
allyl alcohol, carbon dioxide, and water:
CHj.O.CHO CH,
CH.OH « CH +COa+HaO.
CH,.OH CH2.OH
Allyl alcohol is a mobile liquid with a pungent odour ; it is miscible
with water, and burns with a bright flame.
It yields acrolein and acrylic acid when oxidized with silver oxide,
and only formic acid (no acetic) with chromic acid. Glycerol results
when potassium permanganate is the oxidant (B. 21, 3351). Nascent
124 ORGANIC CHEMISTRY
hydrogen attacks it with difficulty, as seems to be indicated by its
formation from acrolein. Boiling with zinc and sulphuric acid (B. 7,
856), however, or with aluminium and potassium hydroxide solution
(C. 1899, II. 181) causes the formation of a small quantity of n-propyl
alcohol; reduction with sodium- ammonium yields pro pylene (C. 1906,
II. 670). Chlorine acts partly as an oxidizing, and partly as an
additive reagent, giving rise to acrolem and dichlorhydrin (B. 24,
2670). When heated to 150° with potassium hydroxide, formic acid,
n-propyl alcohol, and other products are formed.
Allyl alcohol, when heated with mineral acids, yields propionic
aldehyde and methyl ethyl acrolein (B. 20, R. 699).
Mercuric salts form compounds with it, which dissolve with difficulty (B. 33,
2692).
Halogen-substituted Allyl Alcohols have been obtained from a- and /J-dichloro-
propylene and /J-dibromopropylene.
a-Chlorallyl Alcohol, CHa=CCl.CH2OH, b.p. 136*.
0-Chlorallyl Alcohol, CHC1=CH.CH2OH, b.p. 153°.
a-Bromallyl Alcohol, CH2=CBr.CH2OH, b.p. 152°.
Sulphuric acid, acting on a-chlorallyl alcohol, produces acetone-alcohol (q.v.),
and with a-bromallyl alcohol yields propargyl alcohol (see p. 125). a-Brom-
allyl alcohol may be prepared from allyl alcohol by a series of reactions, shown in
the following diagram : —
CHjOCOCH, CHaOH
CBr > CBr
CH, CHa CH2Br CH3 CH, CH,
3. p-Allyl Alcohol, CHa=C(OH).CH3, is^only known in the form of its ether
(p. 129). Sodium ft- allyl Alcoholate is produced by the action of metallic sodium
upon acetone (A. 278, 116), diluted with anyhdrous ether.
4. Crotonyl Alcohol, CH8.CH:CH.CH2OH, b.p. 117-120°, is obtained from
crotonaldehyde, CH3.CH:CH.CHO, by means of nascent hydrogen.
The Higher Olefine Alcohols are synthetically prepared by means of the zinc
and magnesium organic compounds (p. 106) : (i) from olefine aldehydes and
zinc alkyls or magnesium alkyl halides ; or (2) from aldehydes or ketones with
zinc and allyl iodide (B. 17, R. 316; 27, 2434; A. 185, 151, 175; 198, 109;
J. pr. Ch. [2] 30, 399 ; C. 1901, I. 668, 997 ; II. 622 ; 1907, I. 96). (3) Many
aldehydes and ketones, when boiled with acid chlorides, especially benzoyl chloride,
yield the benzoic ester of the olefine alcohols, isomeric with the ketones, e.g.
C,H11.CH:CHO.COC4H6 from cenanthic aldehyde (p. 201 )and benzoyl chloride ;
C,H10C(:CH,)O.COC4H9 from methyl nonyl ketone and valeryl chloride (C. 1913,
I. 71). (4) a/?-olefine carboxylic esters are reduced by sodium and alcohol
to saturated alcohols (see 40, p. 104) ; on the other hand, carboxylic esters con-
taining a remote olefine group, as in the case of allyl acetic acid, oleic acid,
undecylic acid ester, etc., yield the corresponding olefine alcohols when similarly
reduced (C. 1905, I. 25 ; II. 1700).
2, 4-Pentenol, CH3.CH=CH.CH(OH)CH3.
Dimethyl Allyl Carbinol, CHa=CH.CHaC(CH3)oOH, b.p. 119-5°. Diethyl
Allyl Carbinol, b.p. 156°. Methyl Propyl Allyl Carbinol, b.p. 159-160°.
,a28a,..163ai88s,
b.p.18 207°, are obtained from undecylenic ester and oleic ester by reduction.
UNSATURATED ALCOHOLS, CnH2n_3.OH
To this class belong :
Alcohols containing a pair of trebly linked carbon atoms, and alcohols which
contain two pairs of doubly linked carbon atoms. Propargyl alcohol is the only
ALCOHOL DERIVATIVES 125
well-known member of the acetylene series, whereas various alcohols, derived from
diolefines, have not only been synthetically prepared, but have also been discovered
in ethereal oils.
2. ACETYLENE ALCOHOLS
Propargyl Alcohol [Propinol-j], CH : C.CH2OH, b.p. ii4°,D20 = 0-9715. — This
alcohol was obtained by Henry in 1872 (B. 5, 569 ; 8, 389) upon treating a-brom-
allyl alcohol (see p. 124) with potassium hydroxide. It is a mobile, agree-
able smelling liquid. Like acetylene, it forms an explosive silver compound.
C3H2(OH)Ag, white in colour. The copper salt (C3H2OH)2Cu, is a yellow
precipitate.
Homologous acetylene alcohols result from the action of sodium compounds
of the alkyl acetylenes on trioxymethylene or another aldehyde (C. 1 902, I. 629) :
RC | CNa+R'.CHO=RC j CCH (ONa) R'.
Amyl Propiolic Alcohol, CH3[CH3]4C^C.CHaOH, b.p.18 98°.
3. DIOLEFINE ALCOHOLS
Higher alcohols, in which the double union of carbon atoms occurs twice,
are synthetically produced by the action of zinc and allyl iodide on esters of
formic acid and acetic acid (A. 197, 70). Diallyl Carbinol (CH2:CH.CH2)2CHOH,
b.p. 151°. Diallyl Methyl Carbinol (CH2:CH.CH2)2,C(CH3)OH, b.p. 158°. Diallyl
Ethyl Carbinol (CH2:CH.CH2)2C(C2H6)OH, b.p. 175°. Diallyl Propyl Carbinol
(CH2:CH.CH2)2(C3H7)OH, b.p. 194° (C. 1901, I. 997)-
Diolefine alcohols, which can be converted into terpenes, are of great theoretical
interest ; such are geraniol or rhodinol, and linalool. They will be discussed under
the olefinic terpene or terpenogen group (Vol. II.).
ALCOHOL DERIVATIVES
I. SIMPLE AND MIXED ETHERS
Ethers are the oxides of the alcohol radicals. If the alcohols are
compared with basic hydroxides, then the ethers are analogous to the
metallic oxides. They may be considered also as anhydrides of the
alcohols, formed by the elimination of water from two molecules of
alcohol :
C2H6.OH TT (-v CjH6v^
C2H6.OH~~Ha°-C2H6>°-
Ethers containing two similar alcohol radicals are termed simple
ethers ; those with different radicals, mixed ethers :
Ethyl Ether, or Methyl Ethyl
Diethyl Ether. Ether.
The metamerism of ethers among themselves is dependent upon the
homology of the alcohol radicals, which are united by the oxygen
atom (p. 26).
We must make a distinction between the above and the so-called
compound ethers or esters, in which both an alcohol radical and an
acid radical are present — e.g. :
>° Ethyl Acetic Ester ; and O*^0 Ethyl Nitric Ester*
126 ORGANIC CHEMISTRY
The properties of these substances are entirely different from those
of the alcohol ethers, and in the following pages they will always be
termed esters.
The following are the more important methods of preparing the
ethers :
i. The chief method of formation consists of the interaction of
sulphuric acid and alcohols. Alkyl sulphuric acids result at first, but
on further heating with alcohols these are converted into ethers. This
procedure affords a means of obtaining both simple and mixed ethers
(Williamson, Chancel) :
» +CaH8.OH =^g«>0 +H,S04.
Ethyl Sulphuric Diethyl
Acid. Ether.
Methyl Sulphuric Methyl Ethyl
Acid. Ether.
When a mixture of two alcohols reacts with sulphuric acid, three ethers
are simultaneously formed ; two are simple and one is a mixed ether. Sub-
sidiary reactions give rise to the production of sulphones and sulphonic acids
(C. 1897, II. 340 ; 1899, II. 30). Other polybasic acids, such as phosphoric, arsenic,
and boric, behave like sulphuric acid. This is also true of hydrochloric acid
at 170°, and sulpho-acids — e.g. benzene sulphonic acid, at 145° (F. Krafft, B. 26,
2829). In this reaction ethyl benzene sulphonic ester is produced and breaks
down according to the equations :
C6H5SO>H+CaH,OH=C.H8SO3CaH5+HaO.
C6H6SO,CaH6+CaH6OH=CflH6SO,H + (CaH6)aO.
The dialkyl sulphates are converted by alcohols into ethers and alkyl sulphuric
acids much more quickly than the alkyl sulphuric acids (C. 1907, I. 702).
2. The action of the alkylogens on the sodium alcoholates in
alcoholic solution produces mixed ethers.
C2H6.ONa+C8H7Cl=£a|?C>0-f-NaCl.
t-'S"-?
Consult B. 22, R. 381, 637, upon the velocity of these reactions.
3. Halogen-substituted ethers yield homologous ethers on reaction
with zinc or magnesium organic compounds, e.g. bromomethyl amyl
ether (p. 186) and ethyl magnesium bromide yield amyl propyl ether
(C. 1904, I. 1195) :
4. Action of the alkylogens on metallic oxides, especially silver
oxide :
2C2H5I + AgaO = (CaH5)20 -f-2AgI
indicates the constitution of the ethers.
Properties.— Ethers are neutral, volatile (hence the name alOw,
air) bodies, nearly insoluble in water. The lowest members are gases ;
the next higher are liquids, and the highest — e.g. cetyl ether — are
ETHERS OF THE SATURATED OR PARAFFIN ALCOHOLS 127
solids. Their boiling points are very much lower than those of the
corresponding alcohols (A. 243, i).
Reactions. — Chemically, ethers are very indifferent, because all the hydrogen
is attached to carbon.
When oxidized they yield the same products as their alcohols.
They yield ethereal salts when heated with concentrated sulphuric acid.
(3) Phosphorus chloride converts them into alkyl chlorides :
Cc^>0+PCl6=C2H5Cl-fCH8Cl+POCl,.
(4) The same occurs when they are heated with the haloid acids, especially
with HI at 100° (C. 1897, II. 408 ; 1901, II. 679) :
S?S6>0 +2HI =C2H6I -f CH8I +H20.
U.H.3
In the cold the effect of the HI is to cause decomposition into alcohol and
iodide, and in the case of mixed methyl alkyl ethers the production of methyl
iodide and alkyl alcohol predominates. If the alkyl group is a tertiary one, the
iodo-tert-alkyl mainly is produced ; but in other cases a mixture of the two
possible iodides and alcohols results (B. 39, 2569).
C^B3>0 +H1 =CH3I +C2H6OH.
(5) Many ethers, especially those containing secondary and tertiary, or un-
saturated (allyl) groups, are broken down into alcohols when heated with water
or very dilute sulphuric acid at 150° (B. 10, 1903) ; e.g. vinyl ethyl ether decom-
poses into alcohol and aldehyde (B. 39, 1410 footnote).
(6) Ether combines with many substances to form addition compounds, as,
for example, with magnesium or zinc iodide, magnesium alkyl halides (p. 185)
producing bodies of the type 2R2O.MgI2, R2O.MgIR', etc. This is due to the
presence of a tetravalent oxonium oxygen atom (Baeyer and Villiger, B. 34, 2688).
With benzoyl chloride (Vol. II.) the ether magnesium iodide breaks up into
ethyl iodide, ethyl bcnzoate and MgCl2 (C. 1905, I. 1082; B. 38, 3665):
A. ETHERS OF THE SATURATED OR PARAFFIN ALCOHOLS
Methyl Ether, (CH?)aO, is prepared by heating methyl alcohol with sulphuric
acid (B. 7, 699). It is an agreeable-smelling gas, which may be condensed to a
liquid at about —23°. Water dissolves 37 volumes and sulphuric acid upwards
of 600 volumes of the gas.
Chlorine converts methyl ether into chloromethyl ether, sym.-dichlorom ethyl
ether, and perchloromethyl ether which partially decomposes on boiling. The
first two are formaldehyde derivatives, and, together with the corresponding
bromo- and iodo-compounds, will be treated after formaldehyde.
Ethyl Ether or Ether, (CgH^O, m.p. —113° (B. 33, 638), b.p. 35°,
DO = 0*736, is by far the most important representative of this class of
compounds. It has been known for a long time.
History. — Ethyl ether and its production from alcohol and sulphuric acid were
known and described by Valerius Cordus, a German physician, in the six-
teenth century. Until the beginning of the present century ether was regarded
as a sulphur-containing body ; hence, to distinguish it from other ethereal com-
pounds, it was called sulphur-ether. The ether process, in which a comparatively
small quantity of sulphuric acid was capable of converting a large quantity
of alcohol into ether, was included in the category of catalytic reactions. The
explanation of this process constitutes one of the most important advances in
organic chemistry.
128 ORGANIC CHEMISTRY
In 1842, Gerhardt, from purely theoretical reasons and in opposition to Liebig,
concluded that the ether molecule did not contain the same number of carbon
atoms as were present in the alcohol molecule, but twice that number. He
was unable to gain general acceptance for this view. Williamson, in 1850,
by a new synthesis of ether, proved the correctness of Gerhardt 's conception,
not only for it, but for ethers in general ; he caused reaction to take place between
sodium ethoxide and ethyl iodide (p. 126). The formation of ether from alcohol
and sulphuric acid Williamson explained by a continuous breaking-down and
re-formation of ethyl sulphuric acid, made possible by the contact of alcohol
with the acid at 140° (A. 77, 37 ; 81, 73)-
Chancel, who preceded Williamson in publication, had made ether inde-
pendently of the latter, by heating a mixture of potassium ethyl sulphate and
potassium ethoxide :
The objection that ether, because of its low boiling temperature, could not
contain the double number of carbon atoms in its molecule, Chancel removed
by citing the boiling point of ethyl acetic ester (Laurent and Gerhardt, Cr. 1850,
6,369).
Ethyl Alcohol .... C2H8OH .... b.p. 78°.
Ether (C2H5)20 .... b.p. 35°.
Acetic Acid .... CH3CO2H . . . b.p. 118°.
Ethyl Acetic Ester . . CH3CO2C2H6 . . . b.p. 77°.
Thus it was proved that ethyl alcohol and ether were bodies belonging to the
water type (p. 19) — i.e. they might be regarded as water in which one and two
hydrogen atoms were replaced by ethyl :
Preparation. — Ether is made (i) from ethyl alcohol and sulphuric
acid heated to 140°. The process is continuous. (2) From benzene
sulphonic acid and alcohol at 135-145° (B. 26, 2829).
The advantage in the second method is that the ether is not contaminated with
sulphur dioxide, which in the first method has to be removed from the crude
product by washing with a soda solution. Anhydrous ether may be obtained by
distilling ordinary ether over quicklime, and drying it finally with sodium wire
(see aceto acetic ester) until there is no further evolution of hydrogen.
Test for Water and Alcohol. — When ether containing water is shaken with an
equal volume of CS2, a turbidity results. When alcohol is present, the ether,
on shaking with aniline violet, is coloured ; anhydrous ether does not acquire
a colour when similarly treated.
Properties. — Ethyl ether is a mobile liquid with peculiar odour.
It dissolves in 10 parts of water and is miscible with alcohol. Nearly
all the carbon compounds insoluble in water, such as the fats and resins,
are soluble in ether. It is extremely inflammable, burning with a
luminous flame. Its vapour forms a very explosive mixture with air.
When inhaled, ether vapour brings about unconsciousness, a property
discovered in 1842 by Charles Jackson, of Boston,* and has been
used in surgery since Morton's employment of it in 1846. Hoff-
mann's Anodyne, Spiritus Aether eus (so named after the great Halle
clinician, who died in 1742) is a mixture of 3 parts alcohol and I part
ether.
Ether unites with bromine to form peculiar, crystalline addition products
somewhat like the so-called bromine hydrate ; it combines, too, with water,
metallic salts, hydroferrocyanic acid, etc. (see above, p. 127).
* Per Aether gegen den Schmerz, von Binz, Bonn, 1896.
ALKYL HYDROGEN AND DIALKYL PEROXIDES 129
Reactions. — For the action of air on ether, see vinyl alcohol (p. 123). Slow
combustion leads to the formation of diformaldehyde peroxide hydrate. Hydro-
gen peroxide is produced when oxygen acts on moist ether (B. 29, R. 840 ; 38,
1409). When heated with water and sulphuric acid to 180°, ethyl alcohol results.
When ozone is conducted into anhydrous ether, an explosive peroxide is formed.
Chlorine, acting on cooled ether, produces (A. 279, 301) :
Monochlorether, CH8.CHCl.O.CaHf, b.p. 98°.
i,2-Dichlorether, CHaCl.CHCl.O.CaH8, b.p. 145°.
Trichlot ether, (CHCla.CHCl.O.CaH8, b.p. 170-175° (C. 1904, I. 920).
Perchlorether, (C,C16)2O, m.p. 68°, breaks down on distillation
into CaCle and trichloracetyl chloride, CaClaO.Cl. The a-halogen substituted
ethers are closely connected with the aldehyde alcoholates (p. 204).
2-Chloro-t Bromo-, lodo-ethyl Ethers are the ethers of glycol chloro-, bromo-,
and iodo-hydrins— e.g. CHaCl.CHaO.CaII5.
sym.-Dichlorether, CH8.CHCl.O.CHCl.CHa, b.p. 116°, is produced by the action
of hydrochloric acid on aldehyde.
sym.-Di-iodoether (I.CHa.CH2)aO. (See Glycol Halogen Ester.)
The following table contains the melting and boiling points of the better known
simple and mixed ethers : —
Ethyl Methyl Ether .
Methyl tert.-Butyl Ether
n-Propyl Ether •
. b.p.
. b.p.
bo
11°
54°
00°
n-Propyl Methyl Ether
Methyl Isopropyl Ether
Isopropyl Ether •
•
b.p.
h£
37°
32I
70°
Ethyl tert.-Butyl Ether.
Isoamvl Ether .
. b.p.
. b.p.
70°
1 60°
Isopropyl tert.-Butyl Ether
Cetvl Ether (C, .H »») ,O, m.p.
ss°
b£
If
The majority of these ethers are produced by the interaction of alkyl halides
and sodium alcoholates (C. 1903, 1. 119; 1904,!. 1065) ; n-propyl ether is formed
from n-propyl alcohol and ferric chloride, at 145-155° (C. 1904, II. 18). Methyl
tert.-Amyl Ether, (OH8)aC(OCH8).CHaCH8, b.p. 86°, is prepared from trimethyl
ethylene by heating it with methyl alcohol and iodomethane (C. 1907, I. 1125).
B. ETHERS OF UN SATURATED ALCOHOLS
It was explained, when discussing the unsaturated alcohols (p. 123), that the
members of that series in which hydroxyl was combined with a doubly linked
carbon atom readily rearranged themselves into aldehydes or ketones, and were
only known in their derivatives, especially as ethers. Thus :
i. Vinyl Ether, (CHa=CH)aO, b.p. 39°, may be obtained from vinyl sulphide
(p. 143) and silver oxide. 2. Perchlorovinyl Ether, Chloroxethose (CCla=CCl)aO,
is formed from perchlorethyl ether (above) and K2S. 3. Vinyl Ethyl Ether,
b.p. 35*5°, results from the interaction of iodoethyl ether and sodium ethoxide ;
also from acetal by PaO, and quinoline (B. 31, 1021). 4. Isopropenyl Ethyl Ether,
CHSC(OC2H6) =CHa, b.p. 62-63°, is formed from propenyl bromide and alcoholic
potassium hydroxide, and from ethoxycrotonic acid (B. 29, 1005). Also, the
homologues of £-alkoxyacrylic acid easily part with COa and yield the homologues
of alkoxyethylene ether, RC.(OCaH6) :CHR' ; they all yield ketones and alcoho
when hydrolized with dilute acids (C. 1904, I. 719 ; B. 39, 1410 footnote).
Ethers of allyl alcohol and propargyl alcohol are known : Ally I Ether,
(CHa=CH.CHa)aO, b.p. 85°; Propargyl Ethyl Ether. CH-^C.CHa.O.CHa.CH3,
b.p. 80°. (See Ethyl Propiolic Ester.)
ALKYL HYDROGEN AND DIALKYL PEROXIDES
The alkyl hydrogen peroxides and the dialkyl peroxides stand in the same rela-
tion to hydrogen peroxide, as the monohydric alcohols and the ethers do to water :
HO C,H80 C,H40'
HO HO CaH50
Hydrogen Ethyl Hydrogen Diethyl
Peroxide. Peroxide. Peroxide.
Since hydrogen peroxide behaves like a weak acid, the mono- and di-sub-
stituted compounds can be looked upon as the mono- and di-alkyl esters of the acid.
Ethyl hydrogen peroxide and diethyl peroxide are the only members which have
been closely studied. They result from the interaction of diethyl sulphate and
VOL. I. K
I30 ORGANIC CHEMISTRY
a 12 per cent, solution of hydrogen peroxide, and the subsequent slow addition
of potassium hydroxide solution during continuous shaking. An excess of hydrogen
peroxide favours the production of ethyl hydrogen peroxide (Baeyer and Vilhger,
B' E/AW Hydrogen Peroxide, C2H6O.OH, b.p.100 26-47°, is a colourless liquid,
which can be distilled without decomposition, under reduced pressure. It is
miscible with water, alcohol, and ether, and can be separated put from its aqueous
solution by the addition of ammonium sulphate and potassium carbonate. Its
odour is that of bleaching powder and acetaldehyde together. A drop of the con-
centrated solution on the skin causes inflammation. When rapidly heated,
it detonates, and a strong explosion occurs when it is bfought into contact with
very finely divided silver. Acyl derivatives of hydrogen peroxide result from
interaction with carboxylic anhydrides. Tertiary bases are oxidized to amin-
oxides.
Barium salt, (C2H6OO) 2Ba +2H2O, is formed by dissolving barium hydroxide in
an aqueous solution of ethyl hydrogen peroxide. It crystallizes as a leafy mass.
Diethyl Peroxide, CH,CH2.O.O.CH2CH3, b.p. 65°, D^5 = 0-8273. It is slightly
soluble in water, but soluble in alcohol and ether. On contact with a thermometer
heated to 250° it burns rapidly but without noise. If the liquid, in a CO2 atmo-
sphere, is approached by a heated copper wire which is then removed, it disappears
very quickly without generation of light or boiling ; this phenomenon is looked on
as being a slow explosion. The products of combustion consist of formaldehyde
and CO, together with some ethane.
2. ESTERS OF THE MINERAL ACIDS
If we compare the alcohols with the metallic bases, the esters or
compound ethers (p. 126) are perfectly analogous in constitution to
the salts. Just as salts result from the union of metallic hydroxides
with acids, so esters are formed by the combination of alcohols with
acids, water being formed in both reactions :
NaOH+HCl= NaCl+H2O.
C2H6OH+HC1=C2H6C1+H2O.
The haloid esters correspond to the haloid salts ; they may also be
regarded as monohalogen substitution products of the hydrocarbons
(p. 193). Corresponding with the oxygen salts are the esters of other
acids, which, therefore, may be viewed as derivatives of the alcohols,
in which the alcohol-hydrogen has been replaced by acid radicals, or as
derivatives of the acids, in which the hydrogen replaceable by metals
has been substituted by alcohol radicals. The haloid esters would be
included in the last definition of esters. The various definitions of
esters as derivatives of the acids, and again as derivatives of the alcohols,
find expression in the different designations of the esters :
C2H6.O.NO, or N02.O.C2HB.
Ethyl Nitrate. Nitric Ethyl Ester.
In polybasic acids all the hydrogen atoms can be replaced by
alcoholic radicals, whereby neutral esters are produced. When all
the hydrogen atoms are not replaced by alcoholic radicals, acid esters
are formed, which still possess the acid character. They form salts,
hence are termed ester acids, and correspond with acid salts :
Neutral Potassium Sulphate Acid Potassium Sulphate.
co ./O-^Hg cr. ^O.C2H5
bUa<O.C2H6 SO*<OH
Sulphuric Ethyl Ester. Ethyl Sulphuric Acid.
ALKYL ESTERS OF THE HALOGEN ACIDS 131
Dibasic acids form two series of salts, and also of esters, whilst with
tribasic acids there are three series of salts and of esters.
In the case of the polyhydric alcohols there are, besides the neutral esters, also
basic esters, corresponding with the basic salts, in which not all of the hydroxyl
groups were esterified.
Formation of Esters. — (i) The esters can be prepared by direct
combination of alcohols and acids, when water is also produced :
C2Ha.OH+N02.OH=C2H8.O.N02+H20.
This reaction, however, only takes place gradually, progressing with time ;
it is accelerated by heat, but is never complete, free alcohol and acid remain
uncombined together with the ester, and they do not react any further upon each
other. If the ester be removed — e.g. by distillation — from the mixture, as it
is formed, an almost perfect reaction may be attained.
When acted on by alcohols, the polybasic acids mostly yield the
primary esters, the ester- or ether-acids.
There are two synthetic methods of producing the esters which
favour the views of considering them derivatives of alcohols or acids.
These are :
(2) By reacting on the acids (their silver or alkali salts) with
alkylogens :
NOa.O.Ag+CaH6I=NOa.O.C2H6-f-AgI.
(3) By acting on the alcohols or metallic alcoholates with acid
chlorides :
2C2H5.OH+SO2Cla=S02<°'j;2**«+2HCl.
3C8H6.OH + BC13=B(O.C2H6)8 * +3HC1.
Properties. — The neutral esters are insoluble, or soluble with
difficulty in water, and almost all are volatile ; therefore the determina-
tion of their vapour density is a convenient means of establishing the
molecular magnitude and also the basicity of the acids. The ester
acids are not volatile, but are soluble in water and yield salts with the
bases.
All esters, and especially the ester-acids, are decomposed into
alcohols and acids (p. 104) when heated with water. Sodium and
potassium hydroxides, in aqueous or alcoholic solution, accomplish
this with great readiness when heated. This process is termed saponi-
ficalion, because the soaps — i.e. the potassium and sodium salts of the
higher fatty acids (q.v.)- — are obtained by this reaction from the fats,
the glycerol esters :
N02.O.C2H5 + KOH =C2H6OH +NO2OK.
A more general term is hydrolysis ; both words, unfortunately, have become
almost equivalent. — (TR.)
A. I. ALKYL ESTERS OF THE HALOGEN ACIDS, HALOGEN ESTERS OF
THE SATURATED ALCOHOLS, HALOGEN ALKYLS
It was pointed out under the halogen substitution products of the
paraffins and the unsaturated acyclic hydrocarbons that the mono-
halogen substitution products, or alkylogens, were mostly prepared from
the alcohols. This intimate connection wkh the alcohols is the reason
I32 ORGANIC CHEMISTRY
for the assumption of the alkylogens as esters of the haloid acids. As
haloid esters of the alcohols they range themselves with the alkyl
esters of the inorganic oxygen acids.
The view that the halogen derivatives CnH2n+1X are paraffin substitution
products is expressed in the names monochloro-methane, monochloro-ethane,
etc., whilst the designation methyl chloride, ethyl chloride, etc., for the mono-
halogen substitution derivatives of methane and ethane, mark these substances
as haloid esters of the alcohols, corresponding with the metallic halides. The former
mode of expression is, however, preferable, and will in the main be adopted here
except in certain cases for definite reasons, because there is little in the properties
of, say, methyl chloride to connect it with the chlorides as usually understood.
Formation of Alkylogens. — (i) By the substitution of the paraffins. The con-
ditions favouring the substitution of the hydrogen atoms of the paraffins by
halogen atoms have been mentioned under the general methods for the prepara-
tion of halogen substitution products. The substitution reaction is not well
adapted for the preparation of alkylogens, because mixtures of compounds are
invariably produced, and among the higher members of the series isomers
are formed. This is because the chlorine replaces the hydrogen both of terminal
and intermediate carbon atoms (B. 39, 2153). Thus normal pentane,
CH8.CH8.CH,.CH8.CH8 yields CH8.CH2.CHC1.CH2.CH8 and
CH8.CH2.CH2.CHC1.CH,,
CH 3CH ,CH ,CH 2CH ,C1,
and such mixtures are separated with great difficulty.
(2) By the addition of halogen acids to the defines. — In this addition, which
occurs with especial ease with hydriodic acid, it is interesting to note that the
halogen atom attaches itself to the carbon atom carrying the least number of
hydrogen atoms (p. 184) :
HI
CH3.CH=CH, - ;>• CH,.CHI.CH,.
In the case of propylene and hydriodic acid, some iodo-n-propane is also
formed (Michael, B. 39, 2138).
(3) From alcohols (a) by the action of halogen acids. — This reaction
is not complete unless the halogen acid is used in great excess, or the
water formed at the same time with the alkylogen is absorbed. Henco
in the case of methyl and ethyl alcohol an addition of zinc chloride
or sulphuric acid is advantageous (see mono chloro methane, p. 135),
Tertiary alcohols are specially easily converted into chlorides by
hydrochloric acid.
This addition is a disadvantage in the case of the higher alcohols,
because olefines are first produced, and to these the halogen acid
becomes added in such a manner that an isomer of the desired alkylo •
gen is obtained (p. 84). Hence alkyl iodides can be prepared froiu
polyhydric alcohols (comp. Isopropyl Iodide, p. 136) :
C8H4(OH)2 + 3HI=C2H,I + Ia+2H20.
C,H6(OH)8+ 5HI=C8H7I +2l1+3H20.
C4H6(OH)4+ 7HI=C4H,I +3I2+4H20.
8 + iiHI=C.H18I+5I2+6H80.
It may also be remarked that in the presence of an excess of hydriodit
acid the iodides are often reduced.
(b) By the action of phosphorus halides. — If, for example, ethyl
alcohol be treated with PC13, PBr3, or PI8, two possibilities arise I
either a halogen acid and ethyl phosphorous ester are produced,
ALKYL ESTERS OF THE HALOGEN ACIDS 133
or an ethyl halide and phosphorous acid. The latter reaction occurs
when PBr3 and PI3 are used, and this method is adopted almost
exclusively in the preparation of the alkyl bromides and iodides (see
ethyl bromide and ethyl iodide) :
PBr8-f3C2H6OH=3C2H5Br-fH3P08.
PI8+3C2H6OH=3C2H6I +H3P08.
(BI3 acts analogously on ethyl alcohol, B. 24, R. 387.) The for-
mation of esters of phosphorous acid by the use of PBr3 and PI3 is
far from satisfactory. PC13, on the other hand, yields phosphorous
esters and hydrochloric acid almost entirely according to the equation
(C. 1905, II. 1664 ; see p. 141) :
PC1,+3CIH6OH=P(OC2H6)8+3HC1.
The chlorides are readily formed if PC15 be substituted for PC13 :
PC16+C2H6OH=C2H6C1-J-HC1+POC18.
(4) From alkyl halides or alkyl sulphuric acids and metallic halides.
(a) Bromides and iodides can be transformed into chlorides by heating them
withHgCl,:
2C,H7I+HgCl2=2C3H7Cl-fHgIa.
(b) When chlorides are heated with AlBr3 or A1I3 or CaI8 they become con-
verted into bromides or iodides (B. 14, 1709 ; 16, 392 ; 19, R. 166) :
3C2H6Cl+AlBr8=3CaH6Br+AlCl8.
(c) Methyl and ethyl iodides yield with AgF the gaseous compounds methyl
fluoride, CH8F, and ethyl fluoride, C,HBF, which have an agreeable, ethereal
odour, and do not attack glass (B. 22, R. 267).
(</) On distilling ethyl sulphuric acid and potassium bromide, ethyl bromide
is produced. Methyl and ethyl sulphates with alkali iodides in aqueous
solution yield methyl and ethyl iodides.
(e) Magnesium alkyl chlorides or bromides yield iodo-alkyls with iodine
(C. 1903, I. 318) :
C6HuMgCl+Ia=C6H11I+MgCl.
Isomerism. — Propane is the first hydrocarbon capable of yielding
isomers (p. 27). The isomerism depends on the varying position
of the hydrogen atoms in the same carbon chain, and from butane
forward it depends on the different linkage of the carbon atoms forming
the carbon skeleton (see table, p. 134).
Properties and Reactions. — The alkylogens are ethereal, agree-
able, sweet-smelling liquids. They are scarcely soluble in water, but
dissolve with ease in alcohol and ether. They are gases at the ordinary
temperature — e.g. methyl chloride, ethyl chloride, and methyl bromide.
The chlorides boil 28-20° lower than the bromides, and the latter
from 34-28° lower than the corresponding iodides (p. 134). The
differences grow less with increasing molecular weight. As in the case
of the paraffins, here also, where isomers exist, the normal members
have the highest boiling points ; the more branched the carbon chain,
the lower will the boiling point lie.
As halogen esters of the alcohols, the alkylogens may be compared
with the metallic halides, although the halogens are less readily trans-
posed by silver nitrate. The iodides are the most reactive. However,
the alkylogens are excellently adapted to bring about the replacement
of metals, and thus to unite alcohol radicals and atoms which previously
134 ORGANIC CHEMISTRY
were combined with metals. Particularly interesting is the reaction
between the alkaline cyanides (see nitriles), and the sodium deriva-
tives of acetoacetic ester (q.v.) and malonic ester (q.v.). Both are
synthetic reactions of the first importance (p. 75). The alkylogens
play a prominent part in the nucleus-syntheses of the paraffins (see
Ethane, p. 72). They constitute the transition from the paraffins and
defines to the alcohols, into which they are converted, for example,
by moist silver oxide.
The methods for the conversion of alcohols into ethers, into
mercaptans (sulphur-alcohols), into alkyl sulphides (sulphur-ethers)
and compound mineral ethers or esters, are based upon the reactivity
of the halogen atoms in the alkylogens. This is also the case with the
methods employed in the preparation of metal alkyls, especially zinc
alkyls and magnesium alkylogens.
Among the numerous reactions of the alkylogens, mention may
here be made of their power to unite with ammonia and ammonium
bases. By this means the primary, secondary, and tertiary amines, as
well as the tetra-alkyl ammonium halides, were obtained.
The following table contains the boiling points of some of the
alkylogens at the ordinary pressure : —
Name and Formula of Radical.
Chloride.
Bromide.
Iodide.
Methyl-
CH3—
CH3CHa—
-24°
+ 12-5°
+ 4'5°
33°
43°
72°
102°
89-5°
Ethyl-
CH3CH2CH8—
(CH3)2CH—
44°
36-5°
71°
59'5°
Isopropvl- .
n-Butyl-
CH3CH2CH2CH2—
(CH3)2CHCHa-
C^CH-
(CH8)8C—
77-5°
68-5°
100-4°
92°
129-6°
120°
120°
103-3°
sec.-Butyi-
tert.-Butyl- ....
5i'5°
72°
CH3.[CH2]3CH2—
(CH3)2CH.CH2.CH2—
(CaH6)2CH-
CH3CH2CHa>CH~
(CH3)aCH>CH—
fcHihfeG^
czu>°-
1 06°
100°
104°
91°
86°
129°
120°
"3°
II5°
100°
155°
I48°
M5°
I44°
I38°
127°
179°
203°
225°
Isoamyl- ....
Diethyl Methyl- . . .
Methyl n-Propyl Methyl .
Methyl Isopropyl Methyl-
Dimethyl Ethyl Methyl- .
n-Hexyl- ....
CH3[CH2]4CH2-
CH3[CH2]6CHa—
CH3[CH2]6CH2—
o o o
co O\ O
CO >OOO
M M M
155°
178°
199°
n-Heptyl-
n-Octyl- ....
Monofluoromethane CH3F, b.p. -78°, is formed according to mode of pre-
paration (4) (c) (p. 133), and by heating tetramethyl ammonium fluoride (C.
HALOID ESTERS OF THE SATURATED ALCOHOLS 135
Monochloromethane, Methyl Chloride, CH3C1, m.p. —103° (B. 33,
638), is obtained from methane or methyl alcohol. It is a sweet-
smelling gas. Alcohol will dissolve 35 volumes of it, and water
4 volumes.
It is prepared by heating a mixture of i part methyl alcohol (wood spirit),
2 parts sodium chloride, and 3 parts sulphuric acid. A better plan is to conduct
HC1 into boiling methyl alcohol in the presence of zinc chloride (£ part). The
disengaged gas is washed with KOH, and dried by means of sulphuric acid. Com-
mercial methyl chloride is obtained by heating trimethylamine hydrochloride,
N(CH3)3.HC1, and is usually supplied in a compressed condition. It was
formerly employed in the manufacture of the aniline dyes, and in producing
cold.
Monochlorethane, Ethyl Chloride, C2H5C1, b.p. 12-5°, D0 = 0-921. It
is prepared from ethyl alcohol in the same manner that methyl chloride
is obtained from its alcohol. Its formation from " ethyl hydride " or
dimethyl by means of chlorine (p. 72) is important from a theoretical
standpoint.
It is an ethereal liquid, miscible with alcohol, and but sparingly
soluble in water.
If heated with water at 100° in a sealed tube, it changes to ethyl
alcohol, a conversion which is accelerated by potassium hydroxide. In
diffused sunlight, chlorine acts upon it to form ethylidene chloride,
CH3.CHC12, and other substitution products. Of these C2HCl5 was
formerly employed as Mther ancestheticus. Chlorine, in the presence
of iron, converts chlorethane into ethylene chloride.
Myrlcyl chloride, CH3[CH2]a8CH2Cl, m.p. 64°.
Methyl Bromide, Monobromomethane, CH3Br, D0 173 (B. 38,
1865).
Monobromethane, Ethyl Bromide, C2H5Br, b.p. 39° ; D13 = 1*47.
It is prepared from potassium bromide and ethyl sulphuric acid
(p. 126). It is used as a narcotic, and is known as the officinal JEther
bromatus.
Bromopropane, Propyl Bromide, C3H7Br, b.p. 71° ; D20 = 1*3520, is prepared
from the normal alcohol (C. 1906, II. 1042).
Bromo-isopropane, Isopropyl Bromide, C3H7Br, b.p. 59*50° ; D20 = 1*3097, is
obtained from its corresponding alcohol. It is most conveniently prepared by
the action of bromine on isopropyl iodide (B. 15, 1904). On boiling with
aluminium bromide, or by heating to 250°, normal bromopropane is partially
converted into the bromo-isopropane (B. 16, 391). It may be assumed that the
normal bromopropane, CH3.CH2.CH2.Br, at first breaks up into propylene,
CH3.CH:CH2 and HBr, which then, according to a common rule of addition
(p. 84), unites with the propylene to bromo-isopropane, CH3.CHBr.CH8.
Similarly, the bromo-isobutane (CH3)2.CH.CH2.Br, changes at 240° to tert.-
bromobutane, (CH3)2.CBr.CH3. The reactions occurring on heating the halogen
acids with the alcohols may be explained in the same manner.
The table already referred to also contains the boiling points of some of the
higher homologues.
Cetyl Bromide, CH8[CH2]14CH2Br, m.p. 15*.
On exposure to the air the iodides soon become discoloured by
deposition of iodine. The iodides of the secondary and tertiary
136
ORGANIC CHEMISTRY
alcohols are easily converted by heat into alkylenes, CwH2n, and HI.
Consult A 243, 30, upon the specific volumes of the iodo-alkyls.
lodomethane Methyl Iodide, CH3I, b.p. 43°; D0 - 2- 19, is pre-
pared from methyl alcohol, iodine, and phosphorus, or from dimethyl
sulphate and potassium iodide in aqueous solution (C. 1906, II. 1589).
It is a heavy, sweet-smelling liquid, and unites with H2O to form a
crystalline hydrate, 2CH3H-H2O, and with methyl alcohol to form a
compound, 3CH3I+CH3OH, b.p. 40°, without decomposition (C. 1901,
II. 179). At low temperatures the iodo-alkyls take up chlonne, form-
ing extremely easily decomposable iodo chlorides :
Methyl lodochloride, CH,C1,, m.p. -28°, consists of yellow crystals. It decom-
poses into iodine chloride and chloromethane (B. 38, 2842).
lodoethane, Ethyl Iodide, C2H6I, m.p. -113°, DO = i'975. was
discovered by Gay-Lussac in 1815. It is prepared from alcohol, iodine
and phosphorus; or from diethyl sulphate with potassium iodide
solution (C. 1906, II. 1589) . It is a colourless, strongly refracting liquid.
Propyl Iodide, C,H7I, b.p. 102°, Dto i74*7» from propyl alcohol.
lodoisopropane, Isopropyl Iodide, C3H7I, b.p. 89-5°, D2o=i*7°33>
is prepared from isopropyl alcohol, propylene glycol, C3H6(OH)2,or from
propylene, and, most conveniently, by distilling a mixture of glycerol,
amorphous phosphorus, and iodine (A. 138, 364} :
C,H6(OH),+5HI=C,H7H-2lI+3H2O.
Here allyl iodide, CH2=CH— CH2I, is first produced (see below),
which is further changed to propylene, CH2=CH— CH3, and isopropyl
iodide.
The boiling points of some of the higher alkylogens will be found in the pre-
ceding table. Cetyl Iodide, CHg-tCHJ^CH,!, m.p. 22°, and Myricyl Iodide.
CH,[CH2]28CH8I, m.p. 70°.
II. HALOGEN ESTERS OF THE UNSATURATED ALCOHOLS
Only the halogen esters of the most important olefine and acetylene alcohols
will be given ; they are the allyl halides and the propargyl halides. The
former are prepared from allyl alcohol by methods similar to those employed
for the preparation of the corresponding compounds from ethyl alcohol. They
are isomeric with the /3- and a-haloid propylenes (p. 97), from which they are
distinguished by their adaptability for double decompositions :
Formula.
Boiling Point.
Sp. Gravity.
Allyl Fluoride (B. 24, R. 40)
Allyl Chloride ....
Allyl Bromide ....
Allyl Iodide
CH,=CH.CH,F
CHa=CH.CH,Cl
CH,=CH.CH.Br
CHt— CH CH I
-10°
46:
7ii
IOI
0-9379 (20°)
I-46I (0°)
1-780 (16°)
The allyl halides are liquids with leek-like odour. Allyl chloride, heated to
100° with HC1, yields propylene chloride, CH2CHC1.CH2C1. Allyl bromide, heated
to 100° with HBr passes into trimethylene bromide, CHaBr.CH2.CH2Br. The
addition of halogens produces glycerol trihaloid esters.
ESTERS OF NITROUS ACID
137
Allyl Iodide. It is readily prepared from glycerol by the action of
HI, or iodine and phosphorus. It may be supposed that at first
CH2I.CHI.CH2I forms, but is subsequently decomposed into allyl
iodide and iodine. (Preparation : A. 185, 191 ; 226, 206.) With
excess of HI or phosphorus iodide, allyl iodide is further converted
into propylene and isopropyl iodide (see above).
By continued shaking of allyl iodide in alcoholic solution with mercury,
C8H6HgI separates in colourless leaflets (see mercury ethyl). Iodine liberates
pure allyl iodide from this :
C8H6HgI+Ia=C,H5I+HgIt.
Alcoholic potassium hydroxide converts allyl iodide into allyl
ethyl ether. With potassium sulphide it yields allyl sulphide (p. 144) ;
with potassium thiocyanate, allyl thiocyanate, which passes readily
into allyl mustard oil (q.v.). Allyl iodide has also been used in the
synthesis of unsaturated alcohols.
Name.
Formula.
Boiling
Point
Sp. Gravity.
Propargyl Chloride (B. 8, 398)
Propargyl Bromide (B. 7, 761)
Propargyl Iodide (B. 17, 1132)
CH=C.CH2C1
CH^C.CH2Br
CHEEC.CHJ
65°
89°
II5°
1-0454 (5°)
1*5200 (20°)
2-0177 (o°)
Propargyl chloride is produced when phosphorus trichloride acts
on propargyl alcohol.
B. ESTERS OF NITRIC ACID
They are prepared by the interaction of alcohols and nitric acid
(C. 1903, II. 338). Nitrous acid is always produced, as a consequence
of secondary reactions oxidizing and may be destroyed by the
addition of urea :
CO(NH2),+2HNOt=CO,+2Na+3H,O.
When much nitrous acid is present, it induces the decomposition
of the nitric acid ester, and causes explosions.
Methyl Nitric Ester, Methyl Nitrate, b.p. 60° ; D20 = 1-182. When struck or
heated to 150° it explodes very violently.
Ethyl Nitric Ester, Ethyl Nitrate, C2H6.O.NO2, b.p. 86°; D16 = ni2, is a
colourless, pleasant-smelling liquid. It is almost insoluble in water, and burns
with a white light. It will explode if suddenly exposed to a high temperature.
Heated with ammonia, it passes into ethylamine nitrate. Tin and hydrochloric
acid convert it into hydroxylamine.
Propyl Nitrate, C,H7O.NO8 (B. 14, 421), b.p. 110°; Isopropyl Nitrate, b.p.
101-102° ; Isobutyl Nitrate, b.p. 123° ; Isoamyl Nitrate, b.p. 148° ; n-Octyl Nitrate,
b.p.20 no0; Myristyl Nitrate, b.p.lt 175-180°.
C. ESTERS OF NITROUS ACID
These are isomeric with the nitro-paramns. The group NO2 is
present in both ; whilst, however, in the nitro-compounds nitrogen
I38 ORGANIC CHEMISTRY
is combined with carbon, in the esters the union is effected by
oxygen :
C2H6.NO, C2H6.O.NO.
Nitre-ethane. Ethyl Nitrous Ester.
The nitrous esters, as might be inferred from their different structure,
decompose into alcohols and nitrous acid when acted on by alkalis.
Similar treatment will not decompose the nitro-compounds. Nascent
hydrogen (tin and hydrochloric acid) converts the latter into amines,
whilst the esters are hydrolized.
Nitrous acid esters are produced in (i) the action of nitrous acid on the
alcohols in dilute aqueous solution (B. 34, 755) ; (2) by the action of iodo-alkyls
on silver nitrite (B. 25, R. 571) together with nitre-paraffins of much higher
boiling points ; (3) by the introduction of nitrosyl chloride into a pyridine
solution of the alcohol (C. 1903, II. 339)'
Methyl Nitrous Ester, Methyl Nitrite, CH3.O.NO, b.p. -12°.
Ethyl Nitrous Ester, Ethyl Nitrite, C2H5.O.NO, b.p. 16°, D]6 = 0-947, is obtained
by the action of sulphuric acid and potassium nitrite on alcohol (A. 253, 251,
footnote). It is a mobile, yellowish liquid. It is insoluble in water, and possesses
an odour resembling that of apples. It is the active ingredient of Spiritus cetheris
nitrosi.
When ethyl nitrite stands in contact with water it gradually decomposes,
nitrogen oxide being evolved ; an explosion may occur under some conditions.
Hydrogen sulphide changes it into alcohol and ammonia.
n-Butyl Nitrite, C4H9.O.NO, b.p. 75°, sec.-Butyl Nitrite, b.p. 68°, tert.-Butyl
Nitrite, b.p. 77°, n-Oetyl Nitrite, b.p. 175° (C. 1903, II. 339).
Isoamyl Nitrous Ester, C6HltO.NO, b.p. 96° ; D = 0-902, is obtained by pass-
ing nitrous vapours into amyl alcohol at 1 00°. It is a yellow liquid. An explosion
takes place when the vapours are heated to 250°. Nascent hydrogen changes
it into amyl alcohol and ammonia. Heated with methyl alcohol, it is transformed
into methyl nitrite and amyl alcohol ; ethyl alcohol behaves analogously (B. 20,
656).
Amyl nitrite, " Amylium nitrosum," is used in medicine, and also for the
preparation of nitroso- and diazo-compounds.
NOTE.— Diazoethoxane, C2H6O— N=N— OCaH6, results from the interaction
of iodoethane and nitrosyl silver (NOAg)2. It is the ester of hyponitrous acid
(B. 11, 1630).
D. ESTERS OF SULPHURIC ACID
i. The normal, or didlkyl esters are prepared (i) by the interaction of iodo-
alkyls and silver sulphate ; (2) from chlorosulphonic esters or sulphuryl chloride
and sodium alcoholate, together with by-products (C. 1903, II. 936). They
result (3), in small quantities, by heating mono-ethyl sulphuric ester alone,
or the alcohol with sulphuric acid, and can be extracted from the reaction products
by chloroform. A better method is to pass methyl ether into H2SO4 at 160°
(C. 1901, II. 269). Fuming sulphuric acid at ordinary temperatures yields
mainly neutral esters with methyl and ethyl alcohols (C. 1900, II. 614). They are
heavy liquids, soluble in ether, possess an odour like that of peppermint, and
boil without decomposition. They will sink in water, and gradually decompose
into a primary ester and alcohol :
Dimethyl Ester, Dimethyl Sulphate, SO2(OCH3)2, b.p. 188°, is conveniently
prepared by the interaction of methyl alcohol and chlorosulphonic acid. It is
highly irritating to the mucous membrane (C. 1901, I. 265), and is poisonous
(C. 1902, I. 364). It is frequently employed in the preparation of methyl ethers,
esters, and amines (A. 327, 104). Diethyl Ester, Diethyl Sulphate, SO2(OC2H5)a,
u.p. 208°, may also be prepared from SO3 and (C2H6)aO. Heated with alcohol
ESTERS OF SULPHURIC ACID 139
it forms ethyl sulphuric acid and ethyl ether (B. 13, 1699 ; 15, 947) ; it is an excel-
lent reagent for alkylation (B. 33, 2476) (comp. Ethyl Hydrogen Peroxide, p. 129).
Di-isobutyl Ester, b.p.18 134°, and Di-isoamyl Ester, b.p.12 150°, are prepared from
the respective sodium carboxylates and SO2C12 (C. 1903, II • 937).
2. The primary esters or ether-acids are produced (i) when the
alcohols are mixed with concentrated sulphuric acid :
S03(OH)2+C2H6.OH=S02<g£aH*+H20.
The reaction takes place only when aided by heat, and it is not complete.
The reaction proceeds to completion if the alcohol be dissolved in very little
sulphuric acid, and SOS in the form of fuming sulphuric acid be then allowed to
act on the well-cooled solution (B. 28, R. 31). To isolate the ether-acids, the
product of the reaction is diluted with water and boiled with an excess of barium
carbonate. In this way the unaffected sulphuric acid is thrown out as barium
sulphate ; the barium salts of the ether-acids are soluble and crystallize out when
the solution is evaporated. To obtain the acids in a free state their salts are
treated with sulphuric acid or the lead salts (obtained by saturating the acids
with lead carbonate) may be decomposed by hydrogen sulphide, and the solution
allowed to evaporate over sulphuric acid.
Secondary alcohols, also, by careful cooling of the reacting bodies, are capable
of forming ether sulphuric acids — e.g. ethyl propyl carbinol (B. 26, 1203) ; tertiary
alcohols behave similarly (C. 1897, II. 408).
(2) The ether -acids also result from the union of the alkylenes with concentrated
sulphuric acid.
Properties. — These esters are thick liquids, which cannot be distilled,
but which sometimes crystallize. They dissolve readily in water and
alcohol, but are insoluble in ether.
(i) When boiled or warmed with water they break down into
sulphuric acid and alcohol :
(2) When distilled, they yield sulphuric acid and alkylenes (p. 83).
(3) When heated with alcohols, simple and mixed ethers (p. 126)
are produced.
They show a strongly acid reaction, and furnish salts which dissolve
quite readily in water, most of them crystallize readily. The salts
gradually change to sulphates and alcohol when they are boiled
with water. The alkali salts are frequently applied in different
reactions. Thus with KSH and K2S they yield mercaptans and thio-
3thers (p, 143) ; with salts of fatty acids they furnish esters, and with
KCN the alkyl cyanides, etc.
Methyl Sulphuric Acid, SO4(CHa)H, is a thick oil.
Ethyl Sulphuric Acid, SO4(C2HB)H, is obtained by mixing i part alcohol with
2 parts concentrated sulphuric acid, and forms the basis of the Mixt. sulf. acida
(Ph.G.): potassium salt, SO4(C2H6)K, is anhydrous, and crystallizes in plates:
barium and calcium salts crystallize in large tablets with two molecules of
H20 each (A. 218, 300).
The chlorides or chloranhydrides of the ether sulphuric acids ( SO2<Q * 8V
called chlorosulphonic esters, result (i) by the action of sulphuryl chloride on
the alcohols (C. 1903, II. 936 ; 1905, I. 14) :
la=SO,<^iC
Chloride of Ethyl
Sulphuric Acid.
I4o ORGANIC CHEMISTRY
(2) by the action of PC1B on salts of the ether acids ; (3) by the union of the
olefines with C1.SO8H ; (4) by the union of SO3 with the chloro-alkyls ; and (5) by
the action of SO, on the esters of hypochlorous acid (B. 19, 860) :
They are liquids possessing a penetrating odour. Cold water decomposes them
slowly into the alkyl sulphuric acids. The same result accompanied by a violent
evolution of chlorethane is brought about by alcohol. Sodium alcoholates
of chlorosulphonic esters unite to form compounds which break down, giving rise
to normal sulphonic ester, ether, sodium alkyl sulphate, and sodium sulphate.
Aniline and phenols (Vol. II.) are alkylized by chlorosulphonic ester ; sodium
malonic ester and sodium acetic ester are chlorinated (C. 1905, I. 13).
Chloride of Ethyl Sulphuric Acid, C2HB.O.SO2C1, b.p.14 52°; D18 = 1-263.
Methyl Sulphuric Chloride, CH8.O.SO,C1, b.p. 132°.
E. ESTERS OF SULPHUROUS ACID
The empirical formula of sulphurous acid, H2SO3, may have two
possible structures :
SCKoH or HSOj.OH.
sym. -Sulphurous Acid. unsyra. -Sulphurous Acid.
The ordinary sulphites correspond with formula 2, and it appears
that in them one atom of metal is in direct combination with sulphur :
Ag.SO,.OAg K.SO..OH.
Silver Sulphite. Prim. Potassium Sulphite.
Silver sulphite, AgS02.OAg, when acted on by iodoethane, yields
the ethyl ester of ethyl sulphuric acid, C2H5.SO3.C2H5, which loses
an ethyl group when treated with potassium hydroxide, and yields
ethyl sulphuric acid, C2H5.SO3H, the oxidation product of ethyl
mercaptan, C2H5SH. The sulpho-acids and their esters, which must be
viewed as esters of unsymmetrical sulphurous acid, will be described
after the mercaptans.
The esters of symmetrical and unsymmetrical sulphurous acid are closely
connected, as the following shows.
If SO2 is passed into a solution of sodium or potassium alcoholate, or SOa
and NH, into absolute alcohol, there are obtained unstable salts of alkyl sul-
phurous acid— CH.O.SOjNa, C2H6O.SO2K, CsH7O.SOaNa, C2H6O.SO2NH,,
which easily lose SO2 (B. 38, 1298 ; C. 1902, II. 930). These salts are isomeric
with the very stable alkyl sulphonic acid esters (p. 146). If sodium ethyl sulphite
is heated with iodoethane or sodium iodide in alcoholic solution, it is converted
into the double salt of sodium ethyl sulphonate with sodium iodide.
The dialkyl esters of symmetrical sulphurous acid are prepared by the action
of thionyl chloride SOC12 or sulphur chloride on the alcohols :
SOC12+2C2H.OH=SO(OC2HB),+2HC1.
S«C12+3C2H6OH=SO(OC2H6)+C2H8SH+2HC1.
The mercaptan which is formed undergoes further change.
The dialkyl sulphites are liquids, insoluble in water, having an odour of pepper-
mint. They are isomeric with the corresponding esters of the alkyl sulphonic
acids. It is remarkable that aqueous solutions of alkali hydroxides only
hydrolyze the sulphites with difficulty, whilst the prolonged action of a cold con-
centrated solution partially converts them into alkyl sulphonic acids ; a change
which is also brought about by potassium iodide (see above) (B. 38, 1298).
Dimethyl Sulphurous Ester, SO(O.CHj)8, Dimethyl Sulphite, b.p. 121°.
ESTERS OF BORIC ACID
141
Diethyl Sulphita, SO(O.CaHg)a, b.p. 161°, D0 = 1-106, is converted by PCI, into
the chloride, SO<Q Q ^ , b.p. 122°, which is easily decomposed by water into
alcohol, SO, and HC1. It is isomeric with ethyl sulphonic chloride (p. 147), Di-
propyl Sulphite, b.p. 191°.
F. ESTERS OF HYPOCHLOROUS AND PERCHLORIC ACIDS
The Esters of hypochlorous acid, HC1O, are formed by mixing the free acid
with alcohols. They are pungently-smelling, explosive liquids (B. 18, 1767;
19» 857), from which the explosive esters of perchloric acid are obtained by the
action of iodo-alkyls on the silver salt.
Methyl Hypochlorite, b.p. 12° ; Ethyl Hypochlorite, b.p. 36°.
On the behaviour of alkyl hypochlorates and SO,, see p. 140 ; and with
KCN, see chlorimidocarbonic ester.
G. ESTERS OF BORIC ACID, ORTHO-PHOSPHORIC ACID, SYM.-PHOS-
PHOROUS ACID, ARSENIC ACID, SYM.-ARSENIOUS ACID, AND THE
SILICIC ACIDS
These esters are obtained by the action of BC13, B2O3, POC13, PC18, AsBr8, SiCl4,
Si2OCl6 on alcohols and sodium alcoholates. Alkali hydroxides hydrolyze
them with the production of alcohols and alkali salts of the respective inorganic
acids. Most of them are decomposed entirely or in part by water.
Methyl Borate, B(OCH8)3, b.p. 65°, and
Ethyl Borate, B(OCaH6)8, b.p. 119°, both burn with a green flame (C. 1898, II.
1243).
Ethyl Phosphate, PO(OC,HB)8, b.p. 211° (C. 1900, I. 102).
sym.-M ethyl Phosphite, P(OCH8)8, b.p. 111°, and
sym.-Ethyl Phosphite, P(OCaH,)3, b.p. 156°, result from the action of PC13 on the
corresponding sodium alcoholate solution. PC1S and alcohols yield mainly
Dialkyl esters of unsym. -phosphorous acid, HPO(OR) a, which can also be obtained
from the symmetrical trialkyl esters by the action of water or hydrochloric acid.
The latter are isomerized by iodo-alkyls into alkyl phospho-acid esters (comp.
p. 175) with the intermediate formation of addition products (comp. sulphurous
acid esters) :
H2O RI
HPO(OR) a-< P(OR) 3 > RPO(OR) 2.
Cuprous halides also form addition compounds with the trialkyl phosphorous
acid esters (C. 1903, II. 22 ; 1906, II. 1639 ; B. 38, 1171).
Ethyl Arsenate, AsO(OC2H6)3, b.p. 235°, is prepared from silver arsenate and
iodoethane.
sym.-Ethyl Arsenite, As(OC8H5)3, b.p. 166°.
For PhosphO' and Phosphinic acids and the corresponding compounds of
arsenic, comp. the Phosphorus bases and Arsenic bases.
Methyl Orthosilicate, Si(OCH3)4, b.p. 120-122°.
Ethyl Orthosilicate, Si(OCaH6)4, b.p. 165°.
Ethyl Disilicate, Si2O(OCaH8),,, b.p. 236°.
Ethyl Metasilicate, SiO(OCaH5),, b.p. 360° (approximately).
The silicic esters burn with a brilliant white flame. The ortho- and meta-
silicic esters correspond with the o- and m- or ordinary carbonic acid esters :
C(OC2H6)4 and CO(OCaH6)2.
The ortho formic esters HC(OR)3 correspond with the o-silicoformic esters,
HSi(OR)8, which are produced from silicon chloroform, SiHCl8 (see Inorganic
Chemistry) and the alcohols. Ethyl o-Silicoformate, HSi(OCaHR)8, b.p. 134°,
Propyl o-Silicoformate, b.p. 192°, D = 0*885. These esters yield silicon hydride
when heated with sodium (B. 38, 1661).
I42 ORGANIC CHEMISTRY
3. SULPHUR DERIVATIVES OF THE ALCOHOL RADICALS
The hydrosulphides and sulphides correspond with the metallic
hydroxides and oxides, whilst the sulphur analogues of the alcohols
and ethers are the thio-alcohols, mercaptans, or alkyl hydrosulphides,
and thio-ethers or alkyl- sulphides, and the alkali polysulphides find
their analogues in the alkyl polysulphides :
H}0: >; ''"'JO; gjjo: C,H,}o
^}S; ^ C,H }s
Ethyl Hydrosulphide. Ethyl Sulphide.
NaU . C2H5U
Na/S" C2HJS*
Ethyl Disulphide.
A. Mercaptans, Thio-alcohols, or Alkyl Hydrosulphides. — Although
the mercaptans closely resemble the alcohols in general, they
are differentiated in that the hydrogen, which in the alcohols is
replaceable by the alkali metals, is in the mercaptans also to be sub-
stituted by the heavy metals. The mercaptans react very readily
with mercuric oxide, to form crystalline compounds :
2CaH6.SH+HgO = (C2H,.S),Hg+HaO.
Hence their designation as mercaptans (from mer curium captans).
The metal derivatives of the mercaptans are termed mercaptides.
Methods for their formation :
(i) By the action of the alkylogens on potassium hydrosulphide in alcoholic
solution :
C2H5C1 + KSH=C2H5.
(2) By distilling salts of the sulphuric esters with potassium hydrosulphide
or potassium sulphide (see p. 139) :
S02<°£2H6 + KSH =C1Hi.SH + K2SO,.
The neutral esters of sulphuric acid — e.g. SO2(O.C2H6)2 (p. 139) — also yield
mercaptans when heated with KSH.
(3) A direct replacement of the oxygen of alcohols and ethers by sulphur may
be effected by phosphorous sulphide :
5C2H6OH +P2S6 =5C2H5.SH +P305.
(4) By reduction of the chlorides of the sulphonic acids (q.v.) :
C2H6.S02Cl+6H=C2H5SH+HCl+2HaO.
This reaction recalls the reduction of the acid chlorides to primary alcohols
(p. 104).
Properties and Reactions of the Mercaptans. — The mercaptans are
colourless liquids, mostly insoluble in water, and possess a disagree-
able, garlic-like odour.
(1) Moderate oxidation with concentrated sulphuric acid, sulphuryl chloride,
or iodine converts the mercaptans or mercaptides into disulphides (p. 144). The
reaction with iodine permits of these substances being titrated (B. 39, 738).
(2) When oxidized with nitric acid, the mercaptans yield the sulphonic acids.
Conversely, the mercaptans result by the reduction of the sulphonic acids.
SULPHUR DERIVATIVES OF THE ALCOHOL RADICALS 143
(3) By their union with aldehydes and ketones there result mercaptals and
mercaptols—e.g. CH8CH(SC2H6)2, (CH3)2C(SC2H5)2— which will be treated at
the conclusion of the aldehydes and ketones (q.v.).
(4) The mercaptans unite more or less easily to an ethylene linkage, form-
ing sulphides (B. 38, 646).
Ethyl Mercaptan, C2H5.SH, b.p. 36° ; D^ = 0-829. x* is the
most important and was the first discovered mercaptan (1834, Zeiset
A. 11, i). Despite its revolting odour, it is technically made from ethyl
chloride and potassium sulphydrate in the preparation of sulphonal.
It is but slightly soluble in water ; readily in alcohol and ether.
Mercury Mercaptide (C2H5.S)2Hg, m.p. 86°, crystallizes from alcohol
in brilliant leaflets, and is only slightly soluble in water. When
mercaptan is mixed with an alcoholic solution of HgCl2, the compound
C2H5.S.HgCl is precipitated. The potassium and sodium compounds
are best obtained by dissolving the metals in mercaptan diluted with
ether ; they crystallize in white needles.
Methyl Mercaptan, CHaSH, b.p. 6° ; n-Butyl Mercaptan b.p. 98° ;
n-Propyl Mercaptan b.p. 68° ; Allyl Mercaptan, C3H6SH, b.p. 90°.
Isopropyl Mercaptan b.p. 59° ;
Methyl Mercaptan is formed during the fermentation of proteins (B. 34, 201).
n-Butyl Mercaptan is found in secretions of the stink-badger of the Philippines
(Mydaus Marchei Huet) (Pharm. Centralhalle, 1896, No. 34).
B. Sulphides or Thio-ethers are obtained like the mercaptans :
1. By the action of alkylogens on potassium sulphide.
2. By distillation of salts of the ethyl sulphuric acids with potassium
sulphide.
3. By the action of P2S5 on ethers.
4. On heating the lead mercaptides :
2. 2S02<I^5+K2S = (C3H6)2S+2K2S04.
3. 5(C2H5)20+P2S5=5(C2H6)2S+P205.
4. (C,H6S)2Pb = (C2H6)2S+PbS.
Further, by the interaction of alkyl halides with potassium or
sodium mercaptides, when mixed thio-ethers are also produced :
5. C2H6SNa+C2H6I = (C2H6)2S+NaI
C2H6SNa+C8H7I=C2H5.S.C8H7+NaI.
Methods I, 2, and 5 are analogous to those used in the preparation
of the corresponding ethers.
The sulphides, like the mercaptans, are colourless liquids, insoluble in water,
but easily soluble in alcohol and ether. When impure their odour is very dis-
agreeable, but is ethereal when pure (B. 27, 1239).
Reactions. — The sulphides are characterized by their additive power, (i) They
unite with Br2, and (2) with metallic chlorides — e.g. (C2H5)2S.HgCl2,[(C2H6)2S], —
PtCl4 (C. 1900, I. 280 ; 1901, II. 184) ; (3) also with iodo-alkyl to form sulphine
iodides (p. 145) ; (4) they are oxidized to sulphoxides (p. 145) and sulphones
(P- ^45) by nitric acid.
Methyl Sulphide, (CH3)2S, b.p. 37-5°.
Ethyl Sulphide, (C2H,)2S, b.p. 91°.
I44 ORGANIC CHEMISTRY
n-Propyl Sulphide, (C3H7)2S, b.p. 130-135°; n-Butyl Sulphide, b.p. 182°;
Isobutyl Sulphide, [(CH3)aCH.CHa]aS, b.p. 173°; Cetyl Sulphide. (C16H33)2S,
m.p. 57°.
The sulphides of vinyl and allyl alcohols occur in nature. They are far more
(CaH,Bra)aSBra with six
ether (p. 129) (A. 241, 9°)-
with six atoms of bromine. Silver oxide changes it to vinyl
Allyl Sulphide, (CgH^S, b.p. 140°, may be prepared by digesting
allyl iodide with potassium sulphide in alcoholic solution. It is a
colourless, disagreeable smelling oil, but slightly soluble in water.
It forms crystalline precipitates with alcoholic solutions of HgCl2
and PtCl4. With silver nitrate it yields the crystalline compound
(C3H5)2S.2AgN03.
The early statement of Wertheim that allyl sulphide is to be found
in garlic, has not been substantiated ; it is the disulphide which
occurs there (C. 1892, II. 833).
Allyl mustard oil is produced by heating the mercury derivative
with potassium thiocyanate. Vinyl mustard oil is prepared in an
analogous manner.
C. Alkyl Bisulphides are produced (i) like the alkyl rmmosulphides by
distilling salts of the ethyl sulphuric acids or alkylogens with potassium
disulphide (C. 1901, I. 1363) ; (2) by the action of iodine on mercaptans, or con-
centrated sulphuric acid on mercaptides (B. 39, 738) ; (3) by the action of
sulphuryl chloride on the mercaptans :
2. 2CaH6SH+Ia=C2H6S— S— CaH5+2HI.
3. 2CaH5SH+SOaCla==(C2H6)2S2+S02+2HCl.
When bromine acts on a mixture of two mercaptans, mixed alkyl disulphides
are produced (B. 19, 3132). Nascent hydrogen reduces the alkyl disulphides to
mercaptans, whilst zinc dust converts them into zinc mercaptides :
(CaH5)aSa+Zn = (CaH6S)2Zn.
Mercaptides result on heating the disulphides with potassium sulphide (B. 19,
3129) ; magnesium alkyl halides produce sulphides and mercaptides (C. 1906, I.
1244), and dilute nitric acid changes them to alkyl thiosulphonic esters (p. 147).
Methyl Disulphide, (C2H1)2S2, b.p. 112°, and Ethyl Disulphide, (C2H6)2Sa>
b.p. 151°, are oils possessing an odour like that of garlic.
Allyl Disulphide, (C8H6).jS2, b.p.16 117°, occurs with closely connected poly-
sulphides in garlic, Allium sativum (C. 1892, II. 833). The name "allyl" is
derived from this.
D. Sulphlne or Sulphonium Compounds (B. 27, 505 Anm.). (i) The sulphides
of the alcohol radicals (thio-ethers) combine with the iodides, bromides, and
chlorides of the alcohol radicals at ordinary temperatures, more rapidly on
application of heat, and form crystalline compounds :
J = (C2H?)3SI.
Triethyl Sulphonium Iodide.
These are perfectly analogous to the halogen derivatives of the strong basic
radicals. By the action of moist silver oxide the halogen atom in them may be
replaced by hydroxyl, and hydroxides similar to potassium hydroxide are formed :
(CaH6)3S.OH+AgI.
(4)
(5)
SULPHUR DERIVATIVES OF THE ALCOHOL RADICALS 145
(2 ) The sulphine or sulphonium halides are also obtained on heating the sulphur
ethers with the halogen acids, and (3) the alkyl sulphides with iodine (B. 25,
R. 641) :
2(C2H6)2S+HI = (CaH8)8SI-j-CaH8SH.
4(CH,)aS+Ia=2(CH3),SI + (CH8)1S1.
The acid chlorides react similarly to iodine.
By the action of iodomethane on metallic sulphides :
SnS-f-3CH8I=SnIa-f(CH8)8SI.
By heating together sulphur and iodomethane to 180° there is formed
(CH3)3SI.Ia an iodine addition product of trimethyl sulphonium iodide. Similar
compounds are obtained with selenium and tellurium (C. 1904, II. 414).
Often when the iodoalkyls act on the sulphides of higher alkyls the latter are
displaced (B. 8, 825).
f* TT
(CaH6)8S.CH,I and ^ g»>S.CaH8I are not isomeric (in which case a difference
of the 4 valences of S would be proved) but identical (B. 22, R. 648).
The sulphonium hydroxides are crystalline, efflorescent, strongly basic bodies,
readily soluble in water. Like the alkalis, they precipitate metallic hydroxides
from metallic salts, set ammonia free from ammoniacal salts, absorb CO2 and
saturate acids, with the formation of neutral salts :
(CaHi)3S.OH+HN03=(C2H4)3S.N03-fHzO.
We thus observe that relations similar to those noted with the nitrogen group
prevail with sulphur (also with selenium and tellurium). Nitrogen and phos-
phorus combine with four hydrogen atoms, also with alcoholic radicals, to form
the groups ammonium, NH4, and phosphonium, PH4, which yield compounds
similar to those of the alkali metals. Sulphur and its analogues combine in like
manner with three univalent alkyls, and give sulphonium and sulphine deriva-
tives. Other non-metals and the less positive metals, like lead and tin, exhibit a
perfectly similar behaviour. By addition of hydrogen or alkyls they acquire a
strongly basic, metallic character (see the metallo-organic compounds and also
the aromatic iodonium bases, Vol. II.).
Trimethyl Sulphonium Iodide, (CH8)8SI, is readily soluble in water, but is
soluble with difficulty in alcohol, from which it crystallizes in white needles. At
215° it breaks down directly into methyl sulphide and iodomethane. Platinic
chloride precipitates, from solutions of the chloride, a chloroplatinate,
[(CH3)3SCl]2.PtCl4, very similar to ammonium platinum chloride. Trimethyl
Sulphonium Hydroxide, (CH8)3SOH, consists of deliquescent crystals possessing a
strongly alkaline reaction.
Consult B. 24, R. 906, for the refractive power and the lowering of the
freezing point of sulphine compounds.
E. Sulphoxides and Sulphones, as mentioned (p. 143), result from
the oxidation of the sulphides with nitric acid :
CH6v. o ^"
>S
_ . _ .
C2H6 -- C2H6 ' " C2H6
Ethyl Sulphide. Ethyl Sulphoxide. Ethyl Sulphone.
The sulphoxides may be compared with the ketones. Nascent hydrogen reduces
them to sulphides. Methyl and Ethyl Sulphoxides are thick oils, which combine
with nitric acid : (CH3)2SO.HNO8. Barium carbonate liberates the sulphoxides
from these salts. Methyl Sulphoxide is also formed when silver oxide acts upon
methyl sulphobromide, (CH8)2SBra.
The sulphones, obtained from the sulphoxides by means of fuming nitric acid,
or by oxidation vrith potassium permanganate, may also be regarded as esters
of the alkyl sulphinic acids (q.v.), because they can be prepared from salts of thu
latter through the action of iodoalkyls :
However, they are not true esters, but compounds, characterized by great
VOL. I. L
I4g ORGANIC CHEMISTRY
stability, in which both alcohol radicals are linked to sulphur. They cannot be
reduced to sulphides.
Methyl Sulphone, (CH3)2SO2, m.p. 109° ; b.p. 238°.
Ethyl Sulphone, (C2H5)2SO2, m.p. 70° ; b.p. 248 .
ALKYL SULPHONIC ACIDS, ALKYL THIOSULPHURIC ACIDS, ALKYL
THIOSULPHONIC ACIDS, AND ALKYL SULPHINIC ACIDS
These compounds have the general formulae :
R.SCLOH RS.S03H R.SO2SH R.SO2H
CaH5.S02OH C2H5S.S03H C2H5.SO2SH C2H6.SOaH.
Ethyl Sulphonic Ethyl Thiosulphuric Ethyl Thiosulphonic Ethyl Sulphinic
Acid. Acid. Acid. Acid.
F. Sulphonic Acids.
The sulpho-acids or sulphonic acids contain the sulpha-group — SOa.OH —
joined to carbon. This is evident from their production by the oxidation of the
mercaptans, and from their re-conversion into mercaptans (p. 142). They can
be considered as being ester derivatives of the unsymmetrical sulphurous acid,
HSO2OH (p. 140).
Formation. — (i) Their salts result from the interaction of alkali sulphites and
alkyl iodides ; their esters are formed when alkyl iodides 'act on silver sulphite :
K.S02OK+C2H5I=CaH6.S03OK + KI.
Potassium Ethyl Sulphonate.
Ag.SOaOAg+2C1HBI=C1H6.SO,OCIHB+2AgI.
Ethyl Sulphonic Ethyl Ester.
All the esters of sulphurous acid, both sulphite, ROSO2K, and sulphonic
esters, (RO)2SO, when heated with KI form sulphonic acid double salts of the
type (RSO,K)4KI.
(2) By oxidation of (a) the mercaptans ; (b) the alkyl disulphides ; (c) the
alkyl thiocyanates with nitric acid :
C2H6SH)
[C2H5S]2 —5 ^C2H6.S03H.
CaH6S.CN)
(3) The alkyl sulphinic acids are readily oxidized to sulphonic acids.
(4) The sulpho-acids can be formed further by the action of sulphuric acid or
sulphur trioxide on alcohols, ethers, and various other bodies. This reaction
is very common with benzene derivatives and proceeds without difficulty.
Properties and Reactions. — These acids are thick liquids, readily soluble in
water, and generally crystallizable. They undergo decomposition when exposed
to heat (B. 38, 2019), but are not altered when boiled with alkali hydroxides.
When fused with solid alkali hydroxides they break up into sulphites and alcohols :
C2H6.S02.OK + KOH=KS02.OK+C8H6.OH.
PClj changes them to chlorides, — e.g. C2H6.SO2C1, — which are reduced to
mercaptans by hydrogen ; and by the action of sodium alcoholates they pass
into the neutral esters — C2H6.SO3.C2HB (p. 138).
Many of these reactions plainly indicate that in the sulphonic acids the sulphur
is directly combined with the alkyl groups, and that very probably, therefore, in
the sulphites the one metallic atom is directly united to sulphur. The sulphonic
esters boil considerably higher than the esters of symmetrical sulphurous acid
(p. 140). Whilst alcoholic potassium hydroxide converts the latter into potassium
sulphite and alcohol, alkali solutions act only with difficulty and with the partial
production of salts of alkyl sulphonic acid ; in the sulphonic esters the alkyl group
which is not directly combined with sulphur is readily removed by hydrolysis.
Methyl Sulphonic Acid, CH3.SO8H, was synthetically prepared by Kolbe
in 1845 from carbon disulphide, by converting it by means of moist chlorine
into the chloride of trichloromethyl sulphonic acid, CC18SO?C1, and this into the
acid itself, which is reduced by sodium amalgam to methyl sulphonic acid
(A. 54, 174) :
C-t-2S=CSt > CCls.SOaCl >- CCl,.SOtH ^ CH,.SO,H.
SULPHUR DERIVATIVES OF THE ALCOHOL RADICALS 147
Methyl Sulphochloride CH3SO2C1, b.p. 160° ; Ethyl Sulphonate, b.p.10 86°;
Methyl Sulphonic Anhydride (CH3SO,)2O, m.p. 71°, b.p.10 138° (B. 38, 2018).
Ethyl Sulphonic Acid, C2H6.SO3H, is oxidized by concentrated nitric acid to
ethyl sulphuric acid, C2H5O.SO3H (p. 139); lead salt, (C2H6.SO,)2Pb, is readily
soluble; methyl ester, C2HBSOSCHS, b.p. 198°; ethyl ester, CjHj.SOj.CjH^
b.p. 213-4°; ctkyl sulphochloride, C2HB.SOaCl, b.p. 177°.
Ethylene Sulphonie Acid, Vinyl Sulphonic acid, CHa=CHSO8H, is obtained
from ethane disulphochloride, by the action of water and alcohol. Its ammonium
salt, m.p. 156°, reduces alkaline permanganate instantaneously, and combines with
ammonium hydrogen sulphite to form ammonium ethane disulphonate (C. 1898,
II. 1009 ; 1899, I. 1104). Ethylene Sulphone Anilide, CH2:CHSO2NHC,H5, and
Propylene Sulphone Anilide, CH3CH : CHSO2NHC,H5, are obtained from the re-
spective o and /?-alkyl disulphochlorides and aniline with the separation of SO2
and HC1, which takes place even at o° (B. 38, 3626).
G. Alkyl Thi-sulphuric Acids.
(i) The well-crystallized alkali salts of these acids are made by acting on
alkali thiosulphates with primary saturated alkyl iodide (B. 7, 646, 1157) or
bromide (B. 26, 996).
C,H6I+NaS.SOaNa=C2H5S.S03Na+NaI.
Sodium ethyl thiosulphate is called Dunte's salt, after its discoverer. (2) It
also results when iodine acts on a mixture of sodium mercaptide and sodium
sulphite :
C2H6SNa+NaS03Na-fI2=C2H5S.S03Na-f2Nat.
The free acids are not stable. Mineral acids convert sodium ethyl thiosulphate
into mercaptan and mono-sodium sulphate. Heat breaks down the salts into
disulphides, neutral potassium sulphate, and sulphur dioxide. Electroylsis of
Bunte's salt give rise to diethyl disulphide (C. 1901, I. 331).
H. The Alkyl Thiosulphonie Acids.
These acids are only stable as salts and esters. They are formed by the action
of the chlorides of sulpho-acids on potassium sulphide :
C2H6.SO2Cl-fK2S=C2H6.S02SK+KCl.
The esters, R.SO2SR, of this new class were formerly called alkyl disulphoxides,
R2S2O2, and are obtained (i) from the alkali salts by the action of the alkyl
bromides (B. 15, 123) :
CaH6.S02.SK+CaH6Br=C2H6.SO2.SC2H6
and (2) by the oxidation of mercaptans and alkyl disulphides with dilute nitric
acid: (CaH5)2S2-f O2=C2H6.SO2.SC2H5. These esters are liquids, insoluble in
water, and possessed of a disgusting odour (B. 19, 1241, 3131). Ethyl Thio-
suiphuric Ethyl Ester, CaH6.SO2.S.CaH6, b.p. 130-140°.
I. Alkyl Sulphinic Acids The hydrosulphites (see Inorganic Chemistry) can be
looked upon as being salts of a mixed acid anhydride of sulphurous acid and a
hypothetical Sulphoxylic acid, whereby the two following structural formulae arc
possible :
H— S<°H and H>SO«'
Replacing one hydrogen atom, the sulphinic acids result, e.g.,
(i) C2HB.S<°H or (2) Ca**«>SOa.
The true alkyl sulphinic esters are derived from the first formula, whilst the
sulphones can be referred to the second formula (p. 145). The sulphinates are
produced as follows :
(1) By the oxidation of the dry sodium mercaptides in the air.
(2) When SOa acts on the zinc alkyls, or magnesium alkyl halides ; or when
SO,Clt acts on magnesium alkyl halides (B. 37, 2152 ; C. 1905, I, 1143).
I48 ORGANIC CHEMISTRY
(3) When zinc acts on the chlorides of the sulphonic acids
(i)
(2)
2C3
The sulphones (p." 145) are produced "in the action "of iodoalkyls on the
alkali sulphonates, whilst the real esters result from the etherification of the acids
with alcohol and hydrochloric acid, or by the action of chlorocarbonic esters on
the sulphinates (B. 18, 2493) :
R.SOaNa+Cl.C02R=R.SO.OR+COa+NaCl.
When these esters are hydrolyzed by alcohol or water they break down into
alcohol and sulphinic acid, whilst the isomeric sulphones are not altered. The
free sulphinic acids are not very stable. They rapidly dissolve in water and are
oxidized to sulphonic acids. Potassium permanganate and acetic acid convert
the sulphinic esters into sulphonic esters (B. 19, 1225), whereas the isomeric
sulphones remain unchanged.
4. SELENIUM AND TELLURIUM , COMPOUNDS
These are perfectly analogous to the sulphur compounds.
Ethyl Hydroselenide, CaH6.SeH, is'a colourless, unpleasant-smelling, very mobile
liquid. It combines readily with mercuric oxide to form a mercaptide.
Ethyl Selenide, (CaH6),Se, b.p. 108°, is a heavy, yellow oil. It unites directly
with the halogens, e.g. (CaH6)aSeCla. It dissolves in nitric acid with formation
of the oxide, (C2H6)aSeO, which yields the salt, (CaH6)aSe(NO,)a. Ethyl selenite,
SeO(OCaH6)2, b.p. 184°, with slight decomposition, is prepared from selenyl
chloride and sodium ethoxide, or from silver selenite and iodo-ethane. These
reactions demonstrate that the selenites have the constitution SeO(OMe)a, and
that selenious acid is a true dihydroxy-aeid (A. 241, 150).
Tellurium mercaptans are not known. Methyl Telluride, (CH8)aTe, b.p.
80-82°, and Ethyl Telluride, (CaHB)aTe, b.p. 137-5°, are obtained by dis-
tilling barium alkyl sulphate with potassium telluride. They are heavy,
yellow oils. The following compounds are derived from them: (CH8)aTeO,
(CH3)a.TeCl2, (CH3)tTe(N08)a, (CH8)3TeI, (CH3),Te.OH, etc.
Dimethyl Tellurium Oxide, (CH^TeO, is a crystalline efflorescent compound,
resembling, in its basic properties, CaO and PbO. It reacts strongly alkaline,
expels ammonia from ammonium salts, and neutralizes acids.
5. NITROGEN DERIVATIVES OF THE ALCOHOL RADICALS
A I. MONONITRO-PARAFFINS AND OLEFINES, HALOGEN MONONITRO-
PARAFFINS
By nitro-bodies are understood compounds of carbon in which the
hydrogen combined with the latter is replaced by the univalent nitro-
group, N02. The carbon is directly united to the nitrogen, as is shown
by the reduction of the nitro-derivatives yielding amido-compounds :
R.NOa+6H=R.NHa+2HaO.
In the aromatic series the hydrogen atoms of the benzene nucleus
are readily replaced by nitro-groups, e.g. :
C.He+NOsOH=C,H6NOa+HaO.
Nitrobenzene.
Comparative refractometric investigations have shown that the nitro-group in
nitroethane, and that in nitrobenzene, do not have the same structure (Z. ph. Ch.
6, 552). See B. 28, R. 153, for the heat of combustion of the nitro-paramns.
(i) Normal paraffins are very stable towards nitric acid (p. 77),
and are only acted on after prolonged heating at 130-140° with
NITROGEN DERIVATIVES OF THE ALCOHOL RADICALS 149
the dilute acid, whereby substitution products result (Konowalow,
B. 26, R. 108 ; B. 28, 1863 ; C. 1898, I. 926 ; 1899, I. 966, 1063 ;
1902, I. 564 ; 1906, II. 312).
Experience shows that, amongst the fatty bodies, the hydrogen
atom which is attached to a tertiary carbon atom is more easily replaced
by the nitro -group than that which is attached to a secondary carbon
atom, and this, in turn, more easily than one attached to a primary.
Amongst secondary compounds, that hydrogen is the more easily
replaced if its carbon atom is connected to a tertiary radical. Mark-
ownikoff has expressed this in the following rule : In hydrocarbons
that hydrogen is always more easily replaced when attached to a
carbon atom which is affected by other carbon atoms (B. 33, 1907).
(2) A common method for the preparation of the mononitro-
derivatives of fatty hydrocarbons — the nitro-paraffins — consists in
heating the iodides of the alcohol radicals with silver nitrite (V. Meyer,
1872) (A. 171, i ; 175, 88 ; 180, in) :
C,H,I+AgN02=C2H5.N02+AgI.
The isomeric esters of nitrous acid, such as C2H6.O.NO, are formed in this
reaction (B. 15, 1547). From this we would infer that silver nitrite conducted
itself as if apparently consisting of AgNOa and Ag.O.NO. Potassium nitrite
does not act like AgNOa (see Mode of Formation 3) (C. 1907, I. 235). It would
appear that the formation of esters is influenced by the production of alkylens,
which afterwards form esters by the union with HNOa (A. 180, 157; B. 9, 529).
Possibly the alkylogens unite directly with the nitrogen, or in consequence of
an opening-up of the double N=O union.
(3) Simultaneously with the discovery of method 2, Kolbe demonstrated that
nitromethane resulted from the action of potassium nitrite on chloracetic acid.
The first product in this instance was nitroacetic acid, which broke down into
carbon dioxide and nitromethane (J. pr. Ch. [2] 5, 427) :
CH8Cl.COaH >- [CH2(N02).COaH] >- CH,NOa-f COa.
By the same method a-bromopropionic acid and a-bromobutyric acid are made
to yield nitroethane and nitropropane, and so on for the series (C. 1900, I. 126).
(4) The nitro-paraffins are also formed by oxidation of the nitroso-paraffins
(P- I52)-
(5) By a nucleus-synthesis : Zinc alkyls, acting on chloro- and bromo-
nitro-paraffins, produce mononitro-paraffins (B. 26, 129) :
CHj.CHBrNOj - ^^ — > CH8.CH(NO2).CH3, Secondary Nitropropane.
CCls.NOa Zn(CH3)» ->C.N02(CH3)3, Tertiary Nitrobutane.
Properties and Reactions. — The nitro-paramns are colourless,
agreeably smelling liquids, which are sparingly soluble in water. They
distil without decomposition, and only explode with difficulty. Their
boiling points lie considerably higher than those of the corresponding
nitrous esters (p. 137).
The action of potassium and sodium hydroxides on the nitro-paramns is to
form salts when the NO2 group stands next to a hydrogen atom in the molecule.
Similar action on the isomeric nitrous esters results in the production of alcohol
and an alkali nitrite.
Victor Meyer, who discovered the nitro-paraffins and studied them closely,
assumed that, in the salts, the alkali metal was united directly with the carbon
atom (A. 171, 28, 48) ; whilst A. Michael (J. pr. Ch. (1888), [2] 37, 50?) and
later Nef (A. (1894), 280, 263) showed it to be joined to an oxygen atom of the
nitro -group.
Potassium-nitroethane, CH,CHKNOa CHS.CH=NOOK.
According to V. Meyer. According to A, Michael*
I5o ORGANIC CHEMISTRY
The nitro-paraffins are converted by alkalis into isonitro-paraffins (also called
act-nitro-paraffins or nitronic acids), from which the salts are derived (compare
p. 41). If a solution of such an alkali salt is acidified, the isonitro-paraffin which
is first precipitated changes into the corresponding nitro-paraffin. A . F. Holleman
(compare B. 33, 2913) showed how this change could be followed by rapidly
taken conductivity measurements, since the labile, salt-forming isonitro-body is
an electrolyte, which turns into a stable, neutral, non-conducting nitro-compound.
The rapidly falling conductivity runs parallel to the decolorization of the first
formed yellow solution. Hantzsch succeeded in isolating phenylnitromethane
in both its forms— C.H6CHaNO, and C,HBCH : NOOH (B. 29, 1223, 2251 ;
C. 1897, I. 1054).
If a solution of an alkali salt of a primary nitre-paraffin is dropped into ice-
cold dilute hydrochloric acid, a small proportion is converted into a hydroxamic
acid. For instance, potassium pseudonitromethane changes into acetohydro-
xamic acid (Bamberger, B. 35, 49).
By gradual reduction, the nitro-bodies (V. Meyer, B. 24, 3528, 4243; 25,
1714) pass first into alkyl hydroxylamines (p. 171) and then into primary
amines :
CH8N02 - > CH8.NH.OH - >- CH8NHa.
Nitromethane. Methyl Hydroxylamine. Methylamine.
The conversion of nitro-parafiins into primary amines proves, as indicated
before, that the nitrogen of the nitro-group present in them is linked to carbon.
For nitromethane we have the choice between the following formulae (comp.
B. 29, 2263) :
/OH CH2— NOH.
CH.NO,, CH8=N/ , -X^Q
The varying behaviour of the nitro-paraffins with nitrous acid at the moment
of its formation from potassium nitrite and sulphuric acid is very interesting,
according as the nitro-group is linked to primary, secondary, or tertiary radicals.
Primary nitro-compounds in the presence of excess of potassium hydroxide
give rise to an intense red colour due to a soluble, red-coloured alkali salt of a
nitrolic acid, whilst the nitro-compounds of the secondary radicals yield a dark
blue coloration, due to the formation of a pseudo-nitrole :
CH3.CH2N02+NOOH=CH3.Cf^ +H2O.
XNO2
Ethyl Nitrolic Acid
( Ni troace to xime) .
.CH3)2CHN02+NOOH = (CH3)2C<^g +H2O.
Propyl Pseudonitrol.
The nitro-compounds of tertiary radicals do not react with nitrous acid.
Since the alcohols easily form iodides which react with silver nitrate, the pre-
ceding reactions serve as a means of distinguishing primary, secondary, and
tertiary alcoholic radicals from one another (p. 109).
Chlorine and bromine, acting on the alkali salts of primary and secondary
nitro-paraffins, produce chloro- and bromo-nitro-substitution products. In them
the halogen atom occupies the same position as the nitro-group.
Diazpbenzene salts, acting on the alkali salts of the primary nitro-paraffins,
give nitrohydrazones (nitro-azoparaffins), e.g. nitroacetaldehyde hydrazone,
CH,C(NO2) : N.NHC,H5, results from potassium nitroethane and diazobenzene
nitrate (B. 31, 2626 ; see also Vol. II.).
Primary and secondary nitro-paraffins unite with aldehydes in the presence
of alkali carbonates to form nitro-alcohols. As many molecules of an aldehyde
unite with one molecule of a nitro-paramn as there are hydrogen atoms united
to the carbon atom to which the nitro-group is attached. The nitro-alcohols.
as obtained by this method, will be described with the polyatomic alcohols (C. 1897.
NITROGEN DERIVATIVES OF THE ALCOHOL RADICALS 151
II. 1000). Nitromethane and formaldehyde give rise to nitrobutyl glycerol,
the parent substance for the synthesis of glycerol :
,CH o /CH2OH
N02CH3 3 2 > =NOac4-CH2OH.
\CH2OH
i,i-Haloid nitre-paraffins also condense with aldehydes to form meso-halogen
nitro-paraffins, which were described under the section of the nitrogen derivatives
of the ketone-alcohols or ketols.
For compounds resulting from the action of sodium ethoxide and the alkyl
iodides on the nitroethanes, see B. 21, R. 58 and 710.
Zinc ethyl converts nitroethane into /S-ethyl /J-sec.-butyl hydroxylamine
(B. 34,2500).
Primary Mononitroparaffins : Nitromethane, CH8NO2, b.p. 101°, is isomeric
with formhydroxamic acid. Sodium and potassium nitromethane explode with
great violence when they are heated ; this also occurs when these substances,
dried in a desiccator, come into contact with traces of water (B. 27, 3406). When
mercuric chloride acts on sodium nitromethane, mercury fulminate is produced
(q.v.) (A. 280, 275). By the action of potassium hydroxide on nitromethane or of
hydroxylamine hydrochloride on sodium nitromethane, Methazonic Acid,
CH2 : N(O).CH : N(O)OH, m.p. 79°, is formed. It is a mono-basic acid derived
from formic acid (B. 34, 867). Nitroethane, CH3CH2NO, b.p. 113°; reaction
between the sodium salt, CH3CH : NOONa, and benzoyl chloride leads to the
formation of benzoyl acetohydroxamic acid, CH3.C(OH)NO.COC6H6, and not
to the expected benzoyl isonitroethane (C. 1898, I. 564) ; i-Nitropropane,
CH3.CH,.CH2NO2, b.p. 130°; i-Nitro-n.-butane, CH3.CH2.CH2.CH2.NOa, b.p.
151°; Nitroisobutane, (CH3)2CH.CH2NO3, b.p. 137-140°; Nitro-n. -octane,
CHa.[CH2],.CH2.NO2, b.p. 205-210°.
Secondary Mononitroparaffins : Isonitropropane, (CH3)aCHNO2, b.p. 118° ;
Secondary Nitrobutane, C^S>CHNO2, b.p. 138°.
Tertiary Mononitroparaffins : Tertiary Nitrobutane, (CH3)3C.NO2, b.p. 126°;
2-Nitro-2-Methyl Butane, (CH3)2C(NO2)C8HB, b.p. 150° (C. 1903, I. 625).
Nitro-olefines. — Nitro-alcohols, obtained by the condensation of aldehydes
with nitromethane (comp. p. 150), give up water under the' action of zinc
chloride, and form nitro-olefines, RCH : CHNO3 ; Nitroisohexylens (CH2)a
CHCH2CH : CHNO2, b.p.10 80° ; Nitro-octylene, C6H13CH : CHNO2, b.p.g 114°.
Nitroisobutylenet (CH3)C : CHNO2, is prepared by the action of fuming nitric
acid on isobutylene ; and also by the abstraction of CO2 by alkali from dimethyl-
a-nitroacrylic acid. Reduction of the nitro-olefines results in the formation of
the oximes of the paraffin aldehydes (p. 152) (C. 1903, II. 553).
Nitropropylene, CH2 : CH.CH2NO2. b.p.180 88° (C. 1898, I. 192).
Halogen Nitro-compounds result (i) from di-halogen paraffins in which two
different halogen atoms are attached to two C-atoms in the same chain, such as
CH2Cl.CHa.CH2Br, reacting with a mono-molecular quantity of silver nitrate ;
(2) from nitro-paraffins and Cl or Br ; (3) from nitro-alcohols and PC1B. These
substances are acidic in character when a H-atom is united to the same C-atom
as the nitro-group. The remarks which have been made on the constitution of
the salts of the mononitro-paraffins hold good for the salts of the halogen-nitro-
compounds (p. 149).
Chloronitromethane, CH2C1NO2, b.p. 122°; Bromonitromethane, b.p. 146*
(B. 29, 1823) ; Dibromonitromethane (B. 29, 1824).
i,i-Chloronitroethane, CH3.CHC1NO2, b.p. 124°; 1,1 Bromonitroethane,
b.p. 146°; i,2-Chloronitroethane, ClCH2.CHaNOa, b.p. 173°; i,i,i-Dibromo~
nitroethane, CH3.CBr2NOa, b.p. 165°.
i.i-Chhronitropropane, CH3CH2CHC1NO2, b.p. 141°; i,i-Bromonitro-
propane, b.p. 165° ; i-Nitro-2-chloropropane, b.p. 172° ; i-Chloro-2-nitro-
propane, b.p. 170°; i-Chloro-^-nitropropane, b.p. 197°; 2,2-Chloronitropropane,
CH3CCl(NOt).CH3, b.p. 133°; i,2-Bromonitropropane, b.p. 165°; 1,1,1-
Dibromonitropropane, b.p. 185°.
Nitrotriiodoethylene, CI2 : CINO2, m.p. 109°, and Dinitrotriiodoethylene,
NO2CI : CINO2, result from the action of fuming nitric acid or NaO8 on diiodo-
acetylene and tetraiodoethylene respectively (B. 33, 2190).
Following the scheme on which this work is planned, the nitre-halogen
I52 ORGANIC CHEMISTRY
compounds should take their places after the aldehydes, ketones, carboxylic
acids and glycols, according to the position of the substituting atom and group.
It is, however, more convenient not to divide them in this way, except to deal
with Nitrochlorofprm (Chloropicrin), CC13NO,, and Nitrobromoform (Bromopicrin)
in conjunction with CCl4,CBr4,CI4.
The halogen atom in chloro- and bromo-mononitroparaffins can be replaced
by alkyl groups by the action of zinc alkyls, whereby a homologous series of the
mononitroparaffins can be built up (p. 149).
A 2. NITROSOPARAFFINS ; HALOGEN-NITROSOPARAFFINS,
PSEUDONITROLES; NITROLIC ACIDS
The nilroso-group, — NO — , gives its name to those substances which it charac-
terizes— the m>0s0-compounds. Primary and secondary nitrosoparamns cannot,
as a rule, be isolated (comp. B. 35, 2323), since substances of the composition
RCHjNO and R2CH.NO possess a great tendency to transformation into iso-
nitroso-bodies RCH : NOH or aldoximes and ketoximes, RaC : NOH.
Tertiary nitrosoparaffins, on the other hand, are stable and are obtained by
oxidation from j3-alkyl-hydroxylamines (p. 171).
The ketoximes, R2C : NOH, such as acetaldoxime, CH3CH : NOH, are changed
by chlorine or bromine into chloro- or bromo-nitrosoparaffins, RaC<NQ ; by
N2O4 or nitric acid into mtronitrosoparaffins, RaC<CNQa. The latter, also
known as pseudonitroles ', are also obtained (p. 150) by the action of nitrous acid
on the secondary nitre-bodies, whilst the primary compounds yield nitrolic acids,
RC<^TQ|T, under the same treatment. These substances are desmotropic, and
can also be formulated as nitrosonitronic acids-, RC<;NQ
The nitrolic acids occupy a position after the monocarboxylic acids, into wh/ch
they readily change, as well as the amidines, amidoximes, etc. :
Acetic Acid. Acetamidine. Ethenyl Amidoxime. Ethenyl Nitrolic Acids.
The mesohalogen-nitrosoparaffms and the pseudonitroles take their places
systematically after the ketones, from the oximes of which they can also be
prepared, and into which they easily change :
(CH3)aCO (CH3)aC:NOH (CH3)aC<g° (CH,)aC<£gf
Acetone. Acctoxime. Mesobromo- Propyl Pseudonitrole.
nitrosopropane.
However, on account of their connection with the nitro- and nitroso-compounds
these substances will be considered with them.
Nitrosoparaffins. — The direct production of these bodies from the paraffins
has not yet been brought about. Reduction of the nitroparaffins does not yield
nitrosoparaffins, but a series of other bodies. Careful reduction gives rise first
to /J-alkyl hydroxylamines, Alk.NHOH, which will be examined later together
with other alkyl hydroxylamine derivatives (p. 171). But the tert.-alkyl
0- nydroxylamines yield nitrosoparamns by oxidation with chromic acid
R8C.NO, ^ R,C.NHOH >• R3C.NO,
The alkylamines, possessing a tertiary alkyl group, yield tertiary-nitroso-
paraffins when oxidized by permonosulphuric acid, H.SO5, with the intermediate
formation of £-alkyl hydroxylamines :
R8C.NH, ^ R.C.NHOH > R3C.NO.
Sec. -alkyl ^-hydroxylamines are converted by oxidation into ketoximes or
iomtrosoparaffins (p. 151), whilst the primary compounds yield hydroxamic
acias (r>. 36, 701).
Nitroso-compounds are colourless crystalline bodies, having an odour of
camphor, and are very volatile. In the solid state they exist as double molecules,
NITROSOPARAFFINS 153
which are dissociated by heat or solution into the intensely blue coloured mono-
molecular condition. This phenomenon can be observed in many complex
nitroso-bodies (B. 35, 3090). Sunlight retards this dissociation (comp. p. 61).
Nitroso-bodies on oxidation yield nitro-compounds.
Nitroso-tert. -butane, (CH,)3C.NO, m.p. 76°, melts in a closed capillary tube to a
blue liquid, which, on solidification, forms colourless crystals. Nitroso-tert.-pentane,
C2H6C(CH3),NO, m.p. 50°, is prepared by the oxidation of tert.-butyl and amyl-
aniine. Nitrosooctane, (CH8)aCHCH2CHaC(CH8)aNO, m.p. 54°, results from the
reduction of nitrooctane.
meso-Halogen-nitrosoparaffins are prepared by the action of chlorine and
sodium hydroxide (C. 1906, I. 1692), or of bromine and pyridine (B. 35, 3092) on
ketoximes (see above, p. 151) :
They are blue, very volatile bodies, of a sharp odour, and are easily decomposed.
Oxidation changes them into halogen-nitro-bodies (p. 151) ; with silver nitrite
they give rise to the psuedonitroles (see below).
mcso-Chloronitrosopropane, (CH8)2CC1.NO, b.p.18 7°, is formed from (CH8)8-
CNOH and NaClO. An excess of the latter forms chloronitropropane (p. 151).
Bromonitrosopropane, b.p.iei 41 '5°. Bromonitrosobutane, CaH6C(CH8)Br.NO,
b.p.16 28°. Bromonitrosodimethyl Butane, (CH8)8C.C(CH8)Br.NO, m.p. 120°,
with decomposition, form sky-blue crystals which can be sublimed.
i.i-Chloronitrosoethane, CH8CHC1.NO, m.p. 65°, is prepared in a hydro-
chloric acid solution from acetaldoxime, CH3CH : NOH, and chlorine. It changes
on fusion from colourless (dimolecular) plates, to a blue (monomolecular) liquid.
This soon becomes colourless, owing to an isomeric change to acetohydroxamyl
chloride (q.v.) which yields i,i,i-Dichloronitrosoethane, CH3.CCla.NO, a blue-
coloured oil, b.p. 68°, by the further action of chlorine (B. 35, 3113).
Pseudonitroles or meso-Nitronitrosoparaffins. As already described, the pseudo-
nitroles are prepared :
(i) By the action of nitrous acid on sec.-nitroparamns (p. 151) :
(2) From meso-halogen-nitrosoparamns and silver nitrite:
a method indicating its nitronitrosoparamn constitution (B. 35, 3093).
(3) By the action of N2O4 on the ketoximes (see above, halogen-nitroso-
paramns), which is the simplest method of preparation (B. 34, 1911) :
The pseudonitroles are pungent, colourless crystalline substances, dimolecular
when in the solid state. On melting or solution they change into the deep blue
monomolecular form (B. 35, 3094). They possess a neutral reaction, and are
insoluble in water, alkalies, and acids. Chromic acid oxidizes them in glacial
acetic acid solution to Dinitro-bodies. Reduction with hydroxylamine in alkaline
solution changes the pseudonitroles into ketoximes (B. 29, 88, 98).
Propyl Pseudonitrole, Nitronitrosopropane, (CH8)2C(NO2)NO, m.p. 76°, with
decomposition, is changed by NH2OH into Tetramethyl Dinitroazoxy methane,
xN.C(N02)(CH3)a
OC I (B. 34, 1913), Butyl Pseudonitrole, 2,2-Nitronitrosobutane,
XN.C(N02)(CH3)a
m.p. 58°. For the higher homologues, see B. 29, 94 ; 35, 3095.
Nitrolic Acids. — As has already been described (p. 151), the nitrolic acids
result from (i) the action of nitrous acid at the moment of its formation on the
primary mononitro-compounds. (2) A more direct reaction is that of a-isonitroso-
carboxylic acids with N2O4, during which COa is eliminated (C. 1903, II.
)H ,NOH
•fN.Oa-.HCC +COa+HNOi.
)OH XNOt
•<;
154 ORGANIC CHEMISTRY
(3) They can also be obtained from dibromornononitroparaffins and hydro-
xylamine :
/N02
CH,Br2.N02+NH2OH=CH8.C^ +2HBr.
Thus, they are to be considered as being nitro-oximes, but may be desmo tropically
connected with the nitronitroso-bodies :
T^r/NO
KU^NOOH 2
The nitrolic acids are solid, crystalline, colourless, or faintly-yellow coloured
bodies, soluble in water, alcohol, ether, and chloroform. They are weak acids,
and form very explosive salts with alkalis, yielding at the same time a dark-red
colour. The erythronitrolic acid salts are changed by the action of sunlight
and of heat to the colourless leuco-nitrolic acid salts (B. 31, 2854). They are
decomposed into hydroxylamine and the corresponding fatty acids by tin and
hydrochloric acid. When heated with dilute sulphuric acid they split up into
oxides of nitrogen and fatty acids. They are converted into esters when treated
with acid chlorides (B. 27, 1600; 29, 1218). For further reactions, see the
derivatives of the fatty acids.
XN°t
Methyl Nitrolic Acid, CH^ , m.p. 68° with decomposition.
/,
Ethyl Nitrolic Acid, CHS.(X , m.p. 88° with decomposition.
^
/N02
Propyl Nitrolic Acid, CHj.CHj.C^ , m.p. 60° with decomposition.
Appendix. Nitroalkylisonitramines, such as nitroethylisonitramine,
CH3CH(Np2)N2O2H, result from the passage of NO into an alcoholic solution of
an aliphatic mononitro-body, with the addition of sodium ethoxide (A. 300, 106).
Diisonitr amines, such as Methylene Diisonitramine, CH2(N2O2H)2, result
from the action of NO, in the presence of sodium ethoxide, on an alcoholic solution
of a ketone which contains the CO group attached to a methyl or methylene
group (A. 300, 81).
A 3. Dinitroparaflins. — There are three classes of dinitroparaffins ; the
two nitro-groups may be joined —
(1) to one terminal carbon atom : a>z-dinitroparaffins or primary dinitro-
compounds ;
(2) to an intermediate carbon atom : mesodinitroparaffins or secondary
dinitro-compounds ;
(3) to two different carbon atoms.
These three classes, according to the position of the groups, bear the same
relations to aldehydes, ketones, and glycols as do the mononitroparaffins to the
alcohols :
CHtOH CHO CO /CH2OH
I I A CH2<
CH, CH, CH8CH, XCH2OH
CHjNO, CHfNO,), C(NOa)t
CH, CH, CH,CH, <
Notwithstanding these points of relationship, it is practicable to discuss the
dmitroparamns after the bromonitro- and nitrosonitro-bodies (pseudonitroles).
Formation.— (i) By the oxidation of the pseudonitroles with chromic acid
mesodimtropayaffins are produced :
NITROSOPARAFFINS 155
(2) They result from the interaction of potassium nitrite and the bromo-
nitropararnns :
(3) By the action of concentrated nitric acid on
(a) secondary alcohols,
(b) ketones,
(c) mono-alkylized acetoacetic esters,
the carbon chain is torn asunder and (a2-dinitroparaffin$ are formed (C. 1901,
II- 334) :
(C2H6)2CHOH - ^CH3.CH(N02)a
(C2H6)2CO - ^CH3.CH(N02)2
CH,CO.CH(C2H6)C02C2HS - ^CH3.CH2.CH(NOs)a.
The action of iodoalkyls on the salts of the primary dinitroparaffiis results
in the production of mesodinitroparafrins (comp. A. 280, 282).
(4) By the oxidation of saturated monocarboxylic acids, containing a tertiary
carbon atom, with nitric acid : isobutyric and isovaleric acids yield mesodinitro-
propane :
(CHS)2CHC02H (CH3)2CH.CH2.C02H -- ^ (CH3)2C(NO2)2.
The primary dinitro-bodies are acids in which the group CH(NO2)2 changes
into C(NO2) : NOOH. The primary and secondary classes lose hydroxylamine
when they are reduced with tin and hydrochloric acid. The former yield, at the
same time, monocarboxylic acids, and the latter ketones (B. 23, 3494).
Dinitromethane, CH2(NO2)2, is a colourless volatile oil (B. 32, 624). i,i-Di-
nitroethane, CH3CH(NO2)2, b.p. 185-186° (formation, comp. p. 156, Tri-
nitroethane), i.i-Dinitropropane, CH3CH2CH(NO2)2, b.p. 189°; i,i-Dinitro-
hexane, b.p. 212°; 2,2-Dinitropropane, CH3C(NO2)2CH8> m.p. 53°, b.p. 185-5°;
2,2-Dinitrobutane, CH3CH2C(NO2)2.CH3, b.p. 199°. For higher homologues,
see B. 29, 95. Di-tert.-i,2-dinitroparafnns are obtained by the action of finely
divided silver on the mesobromonitroparaffins (p. 152) :
2R2C(NO2)Br+2Ag=RaC(NO2).C(NO2)R2+2AgBr.
Tetramethyl-i,2-dinitroethane, (CH3)2C(NO2).C(NO2)(CH3)2, m.p. 211°, can
be obtained by heating diisopropyl with dilute nitric acid (comp. also p. 148) ;
and by electrolysis of the potassium salt of sec.-nitropropane. Dimethyldiethyl-i. ,
2-dinitroethane, m.p. 80°, is prepared from 2,2-bromonitrobutane (C. 1907,
I. 230). 1,3-Dinitropropane, NOaCHaCH2CH2NO2, is obtained as an unstable
oil from trimethylene iodide and silver nitrate. i,^-Dinitrodiisobutylt
NO2C(CH3)2CH2CH2C(CH3)2NOa, m.p. 125°, is prepared from diisobutyl by heat-
ing it with dilute nitric acid. 1,6-Dinitrodiisoamyl, (CH3)2C(NO2)[CH2]4C(NO2)-
(CH3)2, m.p. 102°, is similarly prepared (B. 25, 2638 ; 28, 1858 ; C. 1906, II.
312 et seq.). These dinitroparaffins yield the corresponding diamines when
reduced.
Polynitroparaflins. Trinitromcthane, Nitroform, CH(NO2)3, m.p. 15°, was
first prepared by the action of water on trinitroacetonitrile, which gave at
the same time COa and ammonium isonitroform. It is also prepared from
tetranitromethane by the action of alcoholic potassium hydroxide or ammonia
with the simultaneous production of ethyl nitrate :
C(NOa),.CN+2H2O = (NO2)2C=NOONH4+COa.
C(NOa)44-C2H6OK = (N02)aC=NOOK+C2H6O.NOt.
It also results from the interaction of acetylene (p. 88) and nitric acid.
It forms colourless crystals, dissolving to a colourless solution in non-aqueous
solvents, but turning yellow in water. The salts are also of a yellow colour, and
are probably derived from isonitroform (NO2)2C=NOOH (p. 150). In non-
dissociating solvents a colourless mercury salt, (NO2)3C.£Hg, is formed, but in
dissociating liquids this exists as (NO2)aC=NOO.£Hg (B. 38, 973). Thus, in
water it assumes the iso- or aci~ condition, and is a very strong mono- basic acid.
156 ORGANIC CHEMISTRY
Free trimtromethene is volatile in steam, and explodes violently on heating.
The freshly prepared potassium salt explodes at 97~99°, and spontaneously
decomposes, on keeping, in dry air. The ammonium compound crystallizes in
yellow needles, and explodes mildly at 200°. The silver salt dissolves easily in
water and in alcohol (B. 32, 628).
Trinitroethane, CH,C(NO,)S, m.p. 56°, is obtained from the silver compound of
trinitromethane and iodomethane ; and also from methylmalonic acid and nitric
acid. It is insoluble in water. Potassium hydroxide solution changes it into
potassium dinitroethane, whilst potassium methoxide produces dinitroethyl
methyl ether, CH8OCHaCH(NO2)a (B. 36, 434).
Bromonitroform, Bromotrinitromethane, C(NO2)3Br, m.p. 12°, is produced
when bromine and nitroform remain in contact for some days in the sunlight.
A quicker method is to pass bromine into an aqueous solution of the mercury
salt of nitroform. It is volatile in steam without decomposition.
Tetranitromethane, C(NO2)4, m.p. 13°, b.p. 126°, D.43 = 1-65, is obtained from
diacetyl orthonitric acid and acetic anhydride (B. 36, 2225) ; also by warming
nitroform with a mixture of fuming nitric acid and sulphuric acid. It is a
colourless oil ; insoluble in water, but easily soluble in alcohol and ether. It is
very stable and distils without exploding. For its transformation into trinitro-
methane, see above.
Tctranitroethane is obtained as a dipotassium salt, KOON : C(NO2).C(NO2) :
NOOK, from bromopicrin, CBr3NO2, and potassium cyanide. It is decomposed
by cold dilute sulphuric acid, forming dinitromethane (B. 35, 4288).
B. ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES
Alkylamines are substances formed by replacement of the hydrogen
atoms in ammonia by alkyl groups.
According as one, two, and three atoms are substituted, there
result the primary, secondary, and tertiary amines :
'C2H6 /CaHB /C2H6
\C2Hj
Ethylamine. Diethylamine. Methyl Triethylamine. Methyl Ethyl-
Ethylamine. Propylamine.
These are also sometimes called amide, imide, and nitrile bases.
Among the secondary and tertiary amines, may be distinguished
simple amines, those with similar alcohol radicals, and mixed amines,
those containing different alcohol radicals (comp. simple and
mixed ethers, p. 125). Derivatives also exist which correspond
with the ammonium salts and hypothetical ammonium hydroxide,
NH4OH :
v v
(CaH6)4NCl. (CaH6)4N.OH.
Tetraethyl Ammonium Chloride. Tetraethyl Ammonium Hydroxide.
known as the quaternary alkyl ammonium compounds. It must be
noticed that the words " primary," " secondary/' and " tertiary " when
applied to alcohols (p. 101) carry different meanings than when em-
ployed with amines, where they indicate the number of alkyl-sub-
stituted hydrogen atoms in an NH3-group. When considering the
close connection between alcohols and amines (comp. pp. 104, 163),
this might lead to confusion.
Isomerism of the Alkylamines.— The isomerism of the simple alkyl-
amines depends on the homology of the alcohol radicles, metamerism!
and in the higher alkylamines, in addition, on the different position
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 157
of the nitrogen in the same carbon chain, isomerism of position ; and
also on the different manner of linkage of the carbon atoms of the
isomeric alkyl residues, nucleus isomerism (p. 25).
There are eight known isomers of C4HnN :
|C4H. (C3H7 _ (C2H,
H
N H N CH, N C2H, N
V/JEl* *l\Vs«
H H
CH
CH
4 Isomeric Butyl- 2 Isomeric Propyl Diethylamine. Ethyl D methylamine.
amines. Methylamines.
History. — The existence of alkylamines, or alcohol bases, was very definitely
predicted by Liebig in 1842 (Hdw. 1, 689). In 1849 Wurtz discovered a method for
the preparation of primary amines, which consisted in decomposing isocyanic ester
with aqueous potassium hydroxide. This was a discovery of the greatest import-
ance for the development of organic chemistry. Shortly afterwards, in 1849, A . W.
Hofmann, by the action of alkylogens on ammonia, discovered a reaction which
made possible the preparation of all the classes described in the preceding para-
graphs : primary, secondary, tertiary amines, and the alkyl ammonium bases.
This afforded the experimental basis for the introduction of the ammonia type into
organic chemistry (comp. p. 19). Since that time numerous other methods
have been found, particularly for the primary amines.
The following general methods are the most important for preparing
the above compounds :
(ia) The iodides, the bromides, or the chlorides of the alcohol
radicals are heated to 100°, in sealed tubes, with alcoholic ammonia
(A. W. Hofmann, 1849). Two reactions occur here: first, the alkyl-
ogens combine with the ammonia, forming alkyl ammonium salts,
which are then partially decomposed by excess of ammonia into
alkylamines, to which alkylogens again unite themselves — e.g. :
NTT
NHS+C2H6I=NH2(C2H6)HI - ? — ^ NH2C2H6 +NHJ.
NH2C2H6+C,H5I=NH(C2H6)2HI -^ — >- NH(C2H6)2+NH4I.
NH(C2H6)2+C2H6I=N(CaH8)8HI ^1_> N(C2H6), +NHJ.
N(CaH5)8+C,H5I=N(C2H6)J.
The final product consists of the hydroiodides of primary, second-
ary, and tertiary amines, i.e. the amide, imide, and nitrile bases,
as well as the quaternary ammonium compounds. The amines are
best obtained on a large scale by the action of ammonia on the
alkyl bromides (B. 22, 700).
Potassium and sodium hydroxides decompose the salts of the
amine, imide, and nitrile bases, with the liberation of the free bases,
whereas the quaternary tetra-alkyl ammonium salts are not decom-
posed by alkali hydroxide, and can thus be easily separated from the
primary, secondary, and tertiary amines (B. 20, 2224).
It is remarkable that the primary and secondary alkyl iodides yield amines,
whilst the tertiary alkyl iodides split off hydrogen iodide and pass into olefines.
On the further alkylation of primary and secondary amines by means of bromo-
alkyls, see B. 38, 1539.
(16) The esters of nitric acid, when heated to iooe with alcoholic ammonia,
react in a manner analogous to the iodoalkyls :
C2H,.O.N02+NHS=C2H6.NH2+KN08.
This reaction is often very convenient for the preparation of the primary
amines (B. 14, 421).
158 ORGANIC CHEMISTRY
(ic) Tertiary amines are produced when primary and secondary bases are
heated with an excess of potassium methyl sulphate (B. 24, 1678) :
(C2H6)2NH+CH8OS03K=(CaH6)8NCH8+HOS03K.
(id) Mono-, di-, and tri-alkylamines are obtained by directly heating the
alcohols to 250-260° with zinc-ammonium chloride, ZnCl2.NH3 (B. 17, 640).
(i <?) The methylation of ammonia and amines can easily be carried out by
means of two reagents — dimethyl sulphate (p. 138) and formaldehyde (p. 197)
(comp. B. 38, 880 ; A. 327, 104 ; C. 1906, II. 1716), e.g. —
NH3 + (CH3)2S04— 2!T->NH2.CH3+H(CH3)S04.
2NH4C1+9CH20 - -^2N(CH8)8.HC1+3C02+3H20.
(2) They are also formed by the action of nascent hydrogen (HC1 and Zn) on
the nitro-paraffins (p. 150), when the alkyl hydroxylamines appear as intermediate
products ; also on the halogen mono-nitro-paraffins :
CH3NO2-}- 4H=CH3NHOH+H2O.
CH3.N02+ 6H=CH3.NH2 +2H2O.
CCl3NO2 + i2H=CH3NHa +2H2O+3HC1.
This method is particularly important in the manufacture of commercially
valuable primary amines — e.g. aniline, C6H6NH2 — from the readily accessible
aromatic nitro-bodies. Zinin discovered the method when investigating the
reduction of nitrobenzene, C6H5NO2, and V. Meyer applied it to the aliphatic
nitro-derivatives.
(3a) By the action of sodium in absolute alcohol on the aldehyde- alkylimides
(B. 29, 2110) ; (36) when zinc dust and hydrochloric acid are allowed to act on
aldehyde-ammonia derivatives (B. 27, R. 437) ; (3^) from the phenylhydrazones
(Tafel), and ($d) the oximes (Goldschmidt) of the aldehydes and ketones by means
of sodium amalgam and glacial acetic acid (B. 19, 1925, 3232 ; 20, 505 ; 22,
1854) :
(CH3) 2CH.CH =N(CH3) +2H = (CH3) 2CH.CH2.NHCHS.
(CH3).CH : N— NH.C6H6+4H=CHs.CH2NHa +C8H6NHa.
(CH3)2C : N— NH.C,H6 +4H = (CH8)2CHNH2+C6H6NH1.
(CH3)2C : N— OH +4H = (CH3)2CHNH2+HaO.
Reaction 30 yields secondary amines, whilst 36, y, and $d give rise to primary
amines, together with some secondary and tertiary amines. The above reactions
can be carried out with molecular hydrogen in presence of finely divided nickel or
copper (C. 1905, II. 540) ; also by electrolytic hydrogen in acid solution (C. 1906,
II. 1539).
(30) Connected with these latter methods of formation is that of primary
amines, accompanied by secondary and tertiary, from aldehydes and ketones by
ammonium formate (A. 343, 54) :
(C8H6)2C=0+HC02NH4=(C2H6)2CH.NH2+COa-fH,O.
(4) The reduction of acid amides with hydrogen from boiling amyl alcohol and
sodium (C. 1899, II. 703) gives a primary amine :
CH3CONHa+4H=HaO+CH8CHaNHs
Acetamide. Ethylamine.
(5) By the action of nascent hydrogen (from alcohol and sodium,
B. 18, 2957 ; 19, 783 ; 22, 1854) on tne nitrites or alkyl cyanides
(Mendius, A. 121, 129) :
HCN+4H=CH8NHa ; CH8.CN+4H=CH3.CHa.NHa.
Methylamine. Acetonitrile. Ethylamine.
This reaction constitutes an important intermediate factor in the synthesis of
both alcohols (p. 105) and amines.
(6) If the isocyanides of the alkyls, the isonitriles, or carbylamines are heated
with dilute hydrochloric acid, formic acid is set free (A. W. Hofmann) :
CaHB.NC+2H20=C2H8.NH2+CHaOa.
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 159
(70) The esters of isocyanic or isocyanuric acid may be distilled with
potassium hydroxide (Wurtz, 1848) :
CO : N.CH3+2KOH==NH2.CH8+KaCO8.
Cyanic acid is changed to ammonia in precisely the same manner :
CO : NH+2KOH=NH8+K2C08.
To convert alcohol radicals into corresponding amines, the iodides are heated
together with silver cyanate ; the product of the reaction is then mixed with
powdered sodium hydroxide, and distilled in an oil bath (B. 10, 131).
(76) The isothiocyanic esters or the mustard oils, etc., are also broken down
into primary amines when heated with water or dilute acids :
CS : N.CaH5+2H20=COa+ HaS+C2H6NH2.
The isocyanic esters and the isothiocyanic esters or mustard oils are alkyl
derivatives of the imide of carbonic acid, and thiocarbonic acid.
(jc) The alkyl compounds of the imide of o-phthalic acid (q.v.) have been
found to be well adapted for the preparation of primary amines. They are
readily prepared by acting on potassium phthalimide with alkyl iodides ; and,
when heated with potassium hydroxide or acids, they separate into phthalic acid
and primary amines (Gabriel, 20, 2224 ; 24, 3104) :
(jd) Secondary amines result, together with benzene sulphochloride, from
the breaking down of a molecule of dialkylamine sulphonic acid, which is obtained
from chlorosulphonic acid and benzene sulphonic dialkylamide, C,H6SO2NRa
(C. 1900, I. 524).
(8) By the distillation of amino-carboxylic acids, especially with barium
hydroxide :
Alanine. Ethylamine.
(9) The decomposition of the secondary and tertiary aromatic p-nitrosamines
into salts of nitrosophenol (q.v.), by means of potassium hydroxide, affords a
means of preparing primary and secondary amines ; p-nitrosodimethylaniline
yields dimethylamine :
NO[4]C6H4[i]N(CH3)a+KOH=NH(CH8)2+NO[4]C8H4[i]OK.
(10) The conversion of the amides of the monocarboxylic acids into
amines containing an atom less of carbon (A W. Hofmann, B. 18, 2734 ;
19, 1822) , can be effected by means of potassium hydroxide and bromine.
This reaction constitutes an intermediate step in the decomposition of the
saturated monocarboxylic acids, because the primary amines can be changed to
alcohols, and the latter be oxidized to carboxylic acids, containing an atom less
of carbon than the fatty acids, whose amides constituted the parent substance.
The reaction proceeds in four stages. The first is the formation
of the " bromamide " of the fatty acid, which, in the second stage,
forms a salt with potassium hydroxide ; in the third, Br splits off and
atomic rearrangement leads to the formation of an alkyl isocyanate,
which, lastly, is broken down by excess of alkali into the primary
amine and potassium carbonate (B. 35, 3579 ; J. pr. Ch. [2] 73, 228^
C. 1903, I. 489) :
I. C2H6CONH2+Br2 + KOH =C2H6CONHBr+KBr+HaO.
II. C2H5CONHBr-f KOH =C2H|(OK) : NBr-j-HaO.
CaH6.C.OK C : O
III. || = || -fKBr.
BrN CaH6N
IV. CaH6NCO+2KOH==CaH,
!6o ORGANIC CHEMISTRY
The bromamide and the alkyl isocyanate can both be isolated under special
conditions.
If one molecule of bromine acts on two of the amide, compound ureas (q.v.)
are formed — acetamide yields acetyl monomethyl urea.
The amides of the fatty acids containing more than 5 C-atoms yield at the same
time an increasing quantity of the nitrile of the next lower acid, e.g. C?H17CONHa
gives C7H16.CN. If, however, the higher bromamide or chloramide is converted
by sodium methoxide into the corresponding urethane and the latter is hydrolysed,
a good yield of the higher primary amine is obtained (B. 30, 898 ; C. 1899, II. 363) .
(lOfl) The above described Hoftnann rearrangement of the bromamide is very
similar to the Bee k mann rearrangement of ketoximes (p. 227), from which primary
amines can also be obtained :
C,H7CCH, O : CCH3 HOCOCH,
HON C3H7NH C,H7NHa.
Propyl methyl . Propyl Propylamine.
Ketoxime. Acetamide.
Another related reaction is the transformation of hydroxamic acids (compare
Benzhydroxamic acid, Vol. II.). Similar, too, is (106) the formation of primary
amines from acid-azides and alcohol. The corresponding acid is converted into
its ester, the ethoxy-group is then replaced with (NH.NHZ) by means of hydrazine
hydrate, the acid-azide, R.CO.NH.NH2, is changed by nitrous acid into the
azide R.CO.N,, which is boiled with water or alcohol, and the resulting urea or
urethane acted on with concentrated hydrochloric acid, when the alkylized
base is liberated (Curtius, B. 27, 779 ; 29, 1166).
R.CO.N, C*H6QIL R.NH.CO.OCaH8 — HQ > R.NH2.
Properties and Reactions of the Amines. — The amines are very
similar to ammonia in their behaviour. The lower members are gases,
possessing an ammoniacal odour, and are very readily soluble in water.
Their combustibility distinguishes them from ammonia, a property
to which WUrtz drew attention in connection with ethylamine (B. 20,
R. 928). The higher members are liquids, readily soluble in water,
and only the highest dissolve with difficulty. Many amines possess
the power of forming hydrates with water, accompanied by very
considerable rise in temperature. They can be dried over potassium
carbonate. Most of the oily hydrates contain one molecule of water
for each nitrogen atom. This can only be removed by means of
potassium hydroxide (B. 27, R. 579), or by distillation over barium
oxide. Like ammonia, they unite directly with acids to form salts,
which differ from ammoniacal salts by their solubility in alcohol.
They combine with some metallic chlorides, and form compounds
perfectly analogous to the ammonium double salts ; e.g. :
[N(CH3)H8Cl]8PtCl4. N(CH8)H8Cl.AuCl8. [N(CH8),HCl]2HgCla.
The ammonia in the alums, the cuprammonium salts and other
compounds may be replaced by amines.
Their basicity is greater than that of ammonia, and increases with
the number of alkyls introduced (J. pr. Ch. [2] 33, 352 ; A. 345, 256).
The reactivity of the primary and secondary amines, as compared
with the tertiary amines, is dependent on the ease with which the
ammonia hydrogen atoms, not substituted by alcohol radicals, are
replaced ; hence, the primary and the secondary amines in many
reactions behave like ammonia.
A primary amine is distinguished from a secondary amine, and this
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 161
from a tertiary amine, by treating the amine alternately with iodo-
methane and potassium hydroxide until all the hydrogen atoms in the
ammonia present are replaced by methyl groups. Whether the latter
have entered, and what their number may be, is most conveniently
determined by the analysis of the platinum double chloride of the base
previous to and after the action of the iodomethane. If two methyl
groups have entered, then the amine was primary ; if one methyl
group has entered, then the base was secondary ; and should the base
remain unchanged, then it is tertiary in its character.
Tertiary, secondary, and primary amines may also be obtained by
the dry distillation of the halogen salts of the ammonium bases, such
as methyl-ammonium hydrochloride :
N(CH8)4C1 = N(CHs)8 -f-CH8Cl
N(CH3),HC1 = NH(CH8)a+CH8Cl
NH(CH3)2HC1 = NHa(CH8)+CH8Cl, etc.
These reactions serve for the commercial production of methyl
chloride (p. 135) from trimethylamine.
Primary and secondary amines show the following reactions :
(i) Primary and secondary amines, like ammonia, react with
acid esters, forming mono- and di-alkylized acid amides (q.v.) and
alcohols. A. W. Hofmann based a method for the separation of
primary, secondary, and tertiary amines upon their behaviour
towards diethyl oxalate (B. 8, 760).
The mixture of the dry bases is treated with diethyl oxalate, when the primary
amine, e.g., methylamine, is changed to diethyloxamide, which is soluble in
water, dimethylamine is converted into the ester of dimethyl oxamic acid (see
oxalic acid compounds), and trimethylamine is not acted on :
Diethyl Oxalate. Dimethyl Oxamide.
•Mti/rw N _i_ COO.C,H5 COO.CaH, nM
•H8)'+COO.C,H. = CON(CH,),+C'H'°H-
Dimethyl Oxamic Ester.
When the reaction-product is distilled, the unaltered trimethylamine passes
over. Water will extract the dimethyl oxamide from the residue ; on distillation
with potassium hydroxide it changes into methylamine and potassium oxalate :
;*'+2KOH=Ca04Ka+2NHa(CH8).
CONH.CH,
The insoluble dimethyl oxamic ester is converted, by distillation with potas-
sium hydroxide, into dimethylamine :
COO.C2H6
CON (CH 3)
The behaviour of the primary and secondary amines towards formaldehyde can
be utilized for their separation from one another (B. 29, R. 520).
(20) The secondary aliphatic amines, e.g. diethylamine (also
piperidine), are readily acted on by a series of non-metallic chlorides,
non-metallic oxy- and sulpho-chlorides, as well as chlorides of inorganic
VOL. I. M
162 ORGANIC CHEMISTRY
acids. The dialkylamine residue replaces one or all of the chlorine
atoms. The products are dialkylized acid amides (B. 29, 710).
Thionyl chloride replaces both the hydrogen atoms in primary
amines by the thionyl residue, with the production of thionylamines,
the alkylized imides of sulphurous acid (Michaelis), which bear the
same relation to sulphur dioxide that the isocyanic esters do to carbon
dioxide.
Nitrosyl chloride, NOC1, and nitrosyl bromide, NOBr, produce from
primary amines alkyl chlorides and bromides, with the formation of
water and nitrogen ; under similar treatment secondary amines yield
nitrosamines (C. 1898, II. 887 ; B. 40, 1052).
The following arrangement, taking diethylamine as example, affords
a review of these reactions :
S— N(CaH6) a Dithio_diethylamine.
S— N(CaH5)a
5'2 Monothio-diethylamine.
Thionyl-ethylamine .
Thionyl-dicthylamine.
SO2<SK255!2 Sulphuryl- or Sulpho-dicthylamine.
JM^2tt6J2
NO.N(C2H6) 2 Nitroso-diethylamine.
PC12N(C2H6) 2 Diethylamine-chlorophosphine.
.^ POClaN(C2H6)2 Diethylamine-oxychlorophosphine.
> PO[N(C2H6)2], Tridiethylamine-phosphine-oxide.
PSC12N(C2H5) 2 Diethylamine-sulphochlorphosphine.
BC12N(C2H5) a Diethylamine-chloroboridc.
SiQ3N(CaH6) a Diethylamine-chlorosilicide.
(26) Primary and secondary amines behave like ammonia towards
organic acid chlorides — e.g. acetyl chloride — forming mono- and di-
alkyl acid amides.
The reaction proceeds twice as fast in the case of the primary
amines as in that of the secondary.
Primary, secondary, and tertiary bases can be separated from
each other by means of benzene sulphochloride, C6H5.SO2C1. In
the presence of alkalis tertiary amines do not react ; under similar
conditions secondary amines yield insoluble di-alkylphenyl sulphamides
C6H5SO2NR2, whilst primary amines form mono-alkylphenyl sul-
phamides C6H5SO2NHR, yielding soluble sodium salts C6H6SO2.NNaR
with aqueous sodium hydroxide, but which are insoluble when pro-
duced by metallic sodium under ether. Dibenzene sulpho-alkyl amides
(C6H5SO2)2NR occur as subsidiary products which form similar
sodium salts C6H5SO2N.NaR when warmed with sodium alcoholate
(B. 38, 908 ; C. 1906, II. 15).
(zc) The primary and secondary amines react similarly with
2,4-dinitro-bromobenzene or 2,4,6-trinitrochloro-benzene as with
acid chlorides (B. 18, R. 540), giving rise to di- and trinitrophenyl
alkyl- and di-alkylamines.
(3) Primary and secondary amines combine with many inorganic
and organic acid anhydrides — e.g. sulphur trioxide, acetic anhydride
— to form amide-acids and acid amides.
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 163
(4) The behaviour of the amines towards nitrous acid is very
characteristic. Primary amines are changed, at least in part, by this
acid into their corresponding alcohols (p. 104) :
C2H6NH2+NO.OH=C2H5OH+N2+H20.
This reaction corresponds with the decomposition of ammonium nitrite
into water and nitrogen :
NH8+NO.OH=H20+N2+H20.
Primary amines containing secondary alkyl groups sometimes yield
tertiary alcohols under these conditions, instead of the expected
secondary alcohol. Nitrosyl chloride and bromide react with primary
amines and give rise to alkyl chlorides and bromides (comp. p. 161).
Nitrous acid converts the secondary amines into nitroso-amines
(p. 168) :
(CH3)2NH+NO.OH = (CH3)2N.NO+H2O
Nitroso-dimethylamine.
whereas the tertiary amines remain unaltered or undergo decomposi-
tion. Indeed, these reactions may be utilized in the separation of
the amines, but naturally the primary amines are lost.
(5) Another procedure, resulting in a partial separation of the amines, depends
on their varying behaviour towards carbon disulphide. The free bases (in aqueous,
alcoholic, or ethereal solution) are digested with CS2, when the primary and
secondary amines form salts of alkyl dithiocarbaminic acid (q.v.), whilst the
tertiary amines remain unaffected, and may be distilled off. On boiling the
residue with HgQ2 or FeCl3, a part of the primary amine is expelled from
the compound as mustard oil (A. W. Hofmann, B. 8, 105, 461 ; 14, 2754 ; and
15, 1290).
(6) A marked characteristic of the primary amines is their ability
to form carbylamines (q.v.), which are easily recognized by their odour
(A. W. Hofmann, B. 3, 767).
(7) By the action of Cl, Br, or I alone or in the presence of alkali hydroxide,
primary and secondary amines yield alkylamine halides (p. 167).
(8) Alkyl magnesium halides (p. 185) react with primary and secondary
amines, generating methane and forming RNHMgl and R2NMgI ; with tertiary
amines a certain proportion of addition compounds is formed R8H<j^ ,.
(9) Oxidation produces varying results. Alkaline permanganate easily
attacks all the amines ; acid permanganate is less active, but still oxidizes with a
velocity of reaction varying according to the structure of the amines, and pro-
duces ammonia, aldehyde, carboxylic acids and other bodies (B. 8, 1237 ; A. 345,
251)-
In the presence of copper powder, oxygen acts on methylamine and ethylamine,
producing formaldehyde and acetaldehyde respectively, together with ammonia
(B. 39, 178).
The various classes of amines can be characterized by their behaviour with
hydrogen peroxide and persulphuric acid (B. 34, 2499 ; 36, 701, 710) :
(a) Primary amines, RNH2, and persulphuric acid yield various products
according as R is a primary, secondary or tertiary alkyl radical. The first stage,
however, in all cases is the formation of alkyl hydroxylamines RNHOH (p. 171),
which are further oxidized to varying results. Alkylamines with primary alkyl
groups yield, together with other bodies, hydroxamic acids (q.v.), easily detected
by the red colour obtained with ferric chloride ; alkylamines containing secondary
groups give ketoximes (p. 153), and with tertiary alkyl groups yield nitroso-
paraffins (p. 153).
i64 ORGANIC CHEMISTRY
(b) Secondary amines R2NH yield di-alkyl hydroxylamines RaN.OH with
hydrogen peroxide.
(c) Tertiary amines and hydrogen peroxide produce tri-alkyl aminoxy-hydrates
R3N(OH)2 (p. 172).
10. Tertiary amines not only form addition compounds with oxygen (tri-alkyl
aminoxy-hydrates) and alkyl halides (tetra-alkyl ammonium halides) as described,
but also with acid chlorides. Such a compound, RaN^ *s verv la-bile,
from which the acyl group is separated in the form of condensation products
(B. 39, 1631), or, when in presence of alcohols or amines, as acyl esters or acyl
amines (B. 39, 2135), together with the formation of tri-alkylamine hydrochlorides.
Cyanogen bromide also forms labile addition compounds with the trialkylamines,
which immediately decompose into bromo-alkyls and dialkyl cyanamide, from
which secondary amines can be produced. These reactions constitute a method
of passing from the tertiary to the secondary amines (B. 38, 1438). Similarly,
hypochlorous acid and trimethylamine form dimethyl chloramine (CH3)2NC1
(comp. B. 38, 2154).
Bromine and iodine also yield addition compounds with tertiary amines
(B. 88,2715, 3904).
(a) Amines and Ammonium Bases with Saturated Alcohol Radicals
(i) Primary Amines. — Methylamine, CH3.NH2, b.p. —6°, occurs
in Mercurialis perennis and annua, in bone-oil, and in the distillate
from wood. It is produced from the methyl ester of isocyanic acid,
by the reduction of chloropicrin, CC13(N02), and hydrocyanic acid,
and by the decomposition of various natural alkaloids, like theine,
creatine, and morphine. The best way of preparing it is by warming
bromacetamide with potassium hydroxide (p. 159), or by the action
of dimethyl sulphate (p. 158) on 10 per cent, ammonia at o° (C. 1906,
II. 1711).
Methylamine is a colourless gas, with an ammoniacal odour. Its combusti-
bility in the air and the lack of solvent action of its aqueous solution on the
oxides of cobalt, nickel, and cadmium distinguish it from ammonia. At 12° one
volume of water dissolves 1150 volumes of the gas. Anhydrous lithium chloride
absorbs considerable quantities of methylamine (C. 1898, II. 970), which also
unites with silver chloride to form CH3NH2.AgCl (C. 1897, I. 1156).
Methyl ammonium chloride, m.p. 210°. Methyl ammonium picrate, m.p. 207",
dissolves with difficulty.
Ethylamine, C2H5.NH2, m.p. —84°, b.p. 18° ; D8=o-696, is a
mobile liquid, which mixes with water in all proportions (B. 33,
638). It expels ammonia from ammoniacal salts, and when in excess
redissolves aluminium hydroxide ; otherwise it behaves in every
respect like ammonia. Highly heated with potassium it becomes
converted into potassium ethylamine C2H5NHK (C. 1897, I. 1157).
Propylamine C3H7NH2, b.p. 49°. Isopropylamine C3H7NH2, b.p. 32°, occuis
in white-thorn. It is prepared by reduction of acetoxime (CH3)C : NOH (p. 158)
(B. 20, 505).
n.-ButylamineCJ^gNH^, b.p. 76°, and Isobutylamine, b.p. 68°, occur in fei-
mentation butyl alcohol. Sec.-Butylamine C2H6CH(CH3)NH2, b.p. 63°, is
obtained in its dextro-rotatory form [0,^ + 7-44° from the oil of Cochlearea officinalis
(B. 36, 582). Tert.-Butylamine, Trimethyl Carbylamine, b.p. 43°. n.-Amylamin*
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 165
CsH^NHa, b.p. 103°. Isoamylamine (CH8)2CHCHaCH2NH?, b.p. 95°, is
obtained when leucine is distilled with alkali hydroxides. It is miscible with water
and burns with aluminous flame. Active Amylamine C2H5CH(CH8)CHNH2,
b.p. 96°, [a]D —5*86°, is produced from optically active amyl alcohol (p. 120) by
means of amyl phthalimide (B. 37, 1047). i,i-Dimelhyl-^-aminobutane
(CH3)3C.CH(NH2).CH3, b.p. 103°, is obtained from pinacoline oxime (C. 1899, II.
474). Dielhyl Carbylamine (CaH5)2CH.NH2, b.p. 90°. Di-n.-propyl Carbylamine
(C3H7)2CH.NH2, b.p. 130°, Diisobutyl Carbylamine (C4H7)aCH.NHa, m.p. 166°,
result from the corresponding ketoxime by reduction with sodium and alcohol
(B. 27, R. 200). n.-Nonylamine C8H19.NHa, b.p. 195°, is already soluble with
difficulty in water. n.-Undecylamine CH3[CH2]10NHa, m.p. 15°, b.p. 232°.
2-Aminononane, b.p.u 69°, and 2-Aminoundecane, b.p.28 114°, are obtained
from heptyl and nonyl methyl ketoxime (B. 36, 2554). n.-Pentadecylamine
CHS[CH2]12NH,, m.p. 36°, b.p. 299° (C. 1899, II. 363) is produced from the corre-
sponding acid chloramides (p. 160).
(2) Secondary Amines. — The secondary amines are also desig-
nated imide bases.
Simple Secondary Amines; Dimethylamine, NH(CH3)2, b.p. 72°,
is most conveniently obtained by boiling nitrosodimethylaniline or
dinitrodimethylaniline with potassium hydroxide (A. 222, 119). It
is a gas that dissolves readily in water. It is condensed to a liquid by
the application of cold.
Diethylamine, NH(C2H5)2, b.p. 56°, is a liquid, which is readily
soluble in water ; hydrochloride, m.p. 76° ; picrate, m.p. 155°.
Di-n.-propylamine, b.p. 110°. Diisopropylamine, b.p. 84° (B. 22, R. 343).
Mixed secondary amines are produced by methods 30 and 36. Methyl Ethylamine,
b'p. 35°. Methyl n.-Propylamine, b.p. 63°. Methyl n,-Butylamine, b.p. 91°.
Methyl n.-Heptylamine, b.p. 171° (B. 29, 2110).
(3) Tertiary Amines. — These are also called nitrite bases, to dis-
tinguish them from alkyl cyanides or acid nitrites.
Trimethylamine, N(CH3)3, b.p. 35°, is isomeric with ethyl methyl-
amine, C2H5.NH.CH3, and the two propylamines, C3H7.NH2. It is
present in herring-brine, and is produced from betaine (q.v.). It is
prepared from herring-brine in large quantities, and also by the
distillation of the " vinasses." It is conveniently obtained by heating
ammonium chloride with formaldehyde (p. 158). Its penetrating,
fish-like smell is characteristic. Hydrochloride, m.p. 271-275° ;
picrate, m.p. 216°, is sparingly soluble (B. 29, R. 590).
Triethylamine, N(C2H6)3, b.p. 89°, is not very soluble in water. It is
produced by heating ethyl isocyanate with sodium ethoxide : CO : N.CaHj-f
2CaH6.ONa=N(CaH6)3+C08Naa.
(4) Tetraalkyl Ammonium Bases. — Whilst neither ammonium
hydroxide nor mono-, di-, or tri-alkyl ammonium hydroxides have
been prepared, yet, by the addition of the iodo-alkyls to the tertiary
amines, tetra-alkyl ammonium iodides are produced ; these, when
tated with moist silver oxide, yield the alkyl ammonium hydroxides :
N(CaH6)J+AgOH=N(CaH6)4.OH4-AgI.
In the interaction of a methyl alcohol solution of tetramethyl
ammonium chloride with a similar solution of potassium hydrox-
ide, KC1 is precipitated, and tetramethyl ammonium hydroxide
/H3)4NOH, is formed. It exists as a pentahydrate, m.p. 63°, a
(CE
ORGANIC CHEMISTRY
trihydrate, m.p. 60°, and a monohydrale, which breaks down into tri-
methylamine at 130-135° (c- I9°5, H. 669).
These hydroxides are perfectly analogous to those of potassium
and sodium. They possess a strong alkaline reaction, saponify fats,
and deliquesce in the air. They crystallize when their aqueous solu-
tions are concentrated in vacuo.- With the acids they yield ammonium
salts, which usually crystallize well.
On exposure to strong heat they break down into tertiary amines,
and alcohols or their decomposition products (CnH2n and H2O) :
N(C2H6)4.OH=N(C2H6),+C2H4-r-H20.
This reaction has acquired special significance because of its appli-
cation in the decomposition of bases of ring-formation (see piperidine
or pentamethylene imide).
Tetramethyl Ammonium Iodide, Tetramethylium Iodide, N(CH3)4I,
and Tetraethyl Ammonium Iodide, Tetraethylium Iodide, N(C2H5)4I,
are prepared from trimethylamine and iodomethane, and iodoethane
and triethylamine respectively ; they consist of white prisms when
crystallized from water or alcohol.
Other salts of the tetra-alkyl ammonium bases are only obtained
with difficulty from the tri-alkylamines by addition, although some-
times the reaction of tertiary amines with dimethyl sulphate can
be used with advantage for preparing methyl sulphuric acid salts
R3C(CH3)OS03CH3. The chlorides can be obtained by the action of
silver chloride on the iodides.
Iodine Addition Products. — (C2H6)4NI.I2, (C2H6)4NI.2l2, and addition pro-
ducts containing even more iodine molecules, are precipitated by iodine from
the aqueous solutions of the tetra-alkylium iodides, e.g. tetraethylium iodide.
Of the numerous compounds belonging here we may mention :
Dimethyl Diethyl Ammonium Iodide, (CH3)2(C2H6)2NI, is obtained from di-
methylamine and ethyl iodide, and from diethylamine and methyl iodide,
methods of formation which should give rise to two substances having as
constitutional formulae :
(CH3)(CH8)(C2H6)N.C2H6I and (C2H6)(C2H6)(CH3)N.CH3I.
These two compounds, however, are identical (A. 180, 173). These facts,
together with the existence and properties of tetra-alkyl ammonium hydroxide,
show that the ammonium compounds are not molecular derivatives, as formerly
assumed (the above formulae are only intended to exhibit the different manner
of formation), but represent true atomic compounds.
On the equivalence or the contrary of the five valencies of nitrogen in ammo-
nium compounds, see Le Bel, B. 23, R. 147. On the asymmetry and optical
activity of tetra-alkyl ammonium compounds in which the substituting groups
consist of four different monovalent alcoholic radicals, see B. 24, R. 441 ; 32,
3508; 33,1003.
(b) Unsaturated Amines and Ammonium Bases
Vinylamine, CH2=CH.NH2, has not yet been prepared. The previously
CH2X
ascribed compound is in reality ethylene imide | \NH.
CH/
Trimethyl Vinyl Ammonium Hydroxide or Neurine, CH2=CH.N(CH3)8OH, is
described after glycol with choline (q.v.), to which it is intimately related.
Allylamine, CH2=CH.CH2.NH2, b.p. 58°, is best obtained from mustard oil
(q.v.). by boiling it with 20 per cent, hydrochloric acid (B. 30, 1124).
Isoallylamine, Propenylamine, CH3.CH=CHNH2, b.p. 67°, is produced by
the action of potassium hydroxide on /J-bromopropylamine (B. 29, 2747).
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 167
Undecenylamine, C^H^NHa, b.p. 239°, and higher homologues, see B. 33,
358o.
Dimethyl Piperidine, Pentallyl Dimethylamine, CHa=CH.CH2.CHa.CH2.-
N(CH3)2, b.p. 117-118°, is a decomposition product of piperidine (q.v.). This
and similar bases unite with hydrochloric acid, and when heated yield ammo-
nium chlorides of pyrrolidine bases (A. 278, i).
Propargylamine, CH=C.CH2NH2, is prepared from dibromallylamine,
CH2Br.CHBr.CH2NH2, and potassium hydroxide. It is probably a gas in a free
condition, but it can only be obtained in alcoholic solution or in the form of
salts (B. 22, 3080).
The following paragraphs, (c) to (h), deal with the alkylamine derivatives of
inorganic acids, whilst the corresponding compounds of the carboxylic acids will
be described with these later.
(c) Alkylamine Halides
These bear the same relation to NC13 and NI3 as the alkylamines to ammonia.
The alkylamine chlorides and bromides may also be regarded as the amides of
hypochlorous and hypobromous acids. Such derivatives are produced by the
action of chlorine, bromine, or iodine, alone or in the presence of alkali hydroxides,
on primary and secondary amines (B. 8, 1470 ; 9, 146 ; 16, 558 ; 23, R. 386 ;
A. 230, 222), as well as by the transposition of acetodibromamide (q.v.) with amines.
When saponified they yield hypochlorous, hypobromous, and hypoiodous acids
(B. 26, 985) :
CH8CH2CH2NHa >- CH3CHaCH2NHCl >- CH.CH.CH.NC1.;
(CHaCHjCHJjNH >• (CH8CHaCH2)2NCl.
The primary alkylamine monohalides are less stable than the dihalides and
the secondary halogen-amines.
Methyl Dichloramine, CH8NC12, b.p. 58-60°, is prepared from methyl ammonium
chloride and bleaching powder. It is a strongly smelling oil, exploding violently
when heated. It forms diazomethane with hydroxylamine (p. 213 ; B. 28, 1682).
Methyl Diiodamine, CH3NI2, is garnet-red in colour. Dimethyl lodamine, (CH3)2NI,
is sulphur-yellow in colour. Ethyl Dichloramine, C2H6NCla, b.p. 88°, is a
strongly smelling, unstable oil (B. 32, 3582). Propyl Chloramine, C8H7NHC1,
volatilizes with decomposition. Propyl Dichloramine t C8H7NC12, b.p. 117°, is a
yellow oil. Dipropyl Chloramine, (C8H7)2NC1, b.p. 143°, etc. (B. 8, 1470; 9,
146 ; 16, 558 ; 23, R. 386 ; 26, R. 188 ; A. 230, 222).
Secondary chloramines give up hydrochloric acid in the presence of alkalis
and change to the alkyl imides of the aldehydes, which take up water in acid
solutions forming a primary amide and an aldehyde :
(CH3)2CH.CHax KOH (CH3)2CH.CHL H.O (CH3)aCH.CHO
>NC1 > >N — 3 >
(CH3)2CH.CH/ (CH8)2CH.CH/ (CH3)aCH.CH2.NH,.
This reaction can be employed for the identification of secondary amines (C.
1897, I. 745).
Nitriles result when the dibromides of the higher primary alkylamines are
treated with alkalis.
(d) Sulphur Derivatives of the Alkylamines
1. Thiodialkylamines, Thiotetr alkyl Diamines, result from the action of SCI,
on dialkylamines in ligroi'n solution. Thiodiethylamine, S[N(C2H5)2]2, b.p.19 87°
(B. 28, 575).
2. Dithiotetralkylamines, Dithiotetralkyl Diamines, result from the action of
S2Cla on dialkylamines in ethereal solution. Dithiodimethylamine, S2[N(CH3)2]1,
b.p.22 82°. Dithiodiethylamine, b.p.22 137° (B. 28, 166).
3. Alkyl-thionylamines, alkylated imides of sulphurous acid, are formed when
thionyl chloride (i mol.) acts on a primary amine (3 mols.) in ethereal solution
(Michaelis, A. 274, 187) :
3CHaNHa+SOClt = CH«N=:SO+2CH NH,.HC1.
168 ORGANIC CHEMISTRY
The members of the series with low boiling points are liquids with penetrating
odour and fume in the air. Water decomposes them into SO2 and the primary
amine. Thionyl Methylamine, CH3NSO, b.p. 58-59°. Thionyl Ethylamine, b.p.
70-75°. Thionyl Isobutylamine, (CH3)2CH.CH2.N : SO, b.p. 117°.
4. Thionyl Dialkylamines, Thionyl Tetralkyldiamines, are formed when thionyl
chloride acts on the ethereal solution of the dialkylamines. Thionyl Biethyl-
amine, OS[N(C2H5)2]a,b.p.a7 118°, corresponds in its composition with tetraethyl
urea (B. 28, 1016).
5. Thionamie Acids are the products resulting from the interaction of sulphur
dioxide and primary amines : ethyl thionamic acid, C2H6NH.SO2H, is a white
hygroscopic powder.
6. Alkyl Sulphamides and Alkyl Sulphaminie Acids. Sulphamides, e.g.
' are formed bv the action of sulphuryl chloride, SO2C12, on
NR
the free secpndary amines, whereas their chlorides, SO2<C1 * result when the
HCl-salts are employed. Water converts the chlorides into sulphaminic acids.
SO2<5Sa (A. 222, 118). SO8 reacts similarly with the primary and secondary
amines, forming mono- and dialkylsulphaminic acids (B. 16, 1265).
(e) Phosphorus Derivatives of the Secondary Alkylamines (B. 29, 710)
1. Dialkylaminochlorophosphines are prepared by the action of phosphorus
trichloride on the dialkylamines. They are liquids which give off fumes in the
air, and possess an irritating odour. Diethylaminochlorophosphine, (C2H6)2N.PC12,
b.p.14 73°. Diisobutylaminochlorophosphine, m.p. 37°, b.p.18 116°.
2. Dialkylaminoxychiorophosphines are obtained by the action of phosphorus
oxychloride on secondary amines in aqueous solution. They are stable bodies,
possessing a camphor- or pepper-like odour. Diethylaminoxychlorophosphine,
(C2H6)2N.POC12, b.p. i6 100°. Di-n-propylaminoxychlorophosphine, b.p.80 170°.
Diisobutylaminoxychlorophcsphine, m.p. 54°.
3. Dialkylaminosulphocholorophosphines are formed when phosphorus sulpho-
chloride acts on dialkylamines. They can be distilled in steam, and smell
like camphor. Diethylaminosulphochlorophosphine, (C2H6)2N.PSC12, b.p.lf 100°.
Dipropylaminosulphochlorophosphine, b.p.16 133°. Diisobutylaminosulphochloro-
phosphine, b.p.10 150°.
(/)> (g)> CO Arsenic, Boron, and Silicon Derivatives o! the Secondary Amines
(B. 29, 714)
Diisobutylaminochlorarsinc, (C4H9)2N.AsCl2, b.p.15 125°.
Diethylaminochloroborinc, (C2H6)2N.BC12, b.p. 142°. Fumes strongly in air.
Dipropylaminochloroborine, b.p.45 99°. Diisobutylaminochloroborine, b.p. 1 7 93°.
Diethylaminochlorosilicine, (C8H6)2N.SiCl8, b.p.80 104°. Diisobutylamino-
chlorosilicine, b.p.30 122°.
The chlorarsines, chloroborines, and chlorosilicines of the secondary bases are
prepared in the same way as the chlorophosphines from the corresponding
chlorides.
(t) Nitroso-amines
AU basic secondary amines (imides), like (CH8)2NH and (C2H6)2NH, can be
converted into nitroso-amines (nitrosamines) by the replacement of the hydrogen
of the imide group. They are obtained from the free imides by the action of
nitrous acid on their aqueous, ethereal, or glacial acetic acid solutions, or by
warming their salts in aqueous or acid solution with potassium nitrite (p. 163)
(B. 9, in). They are mostly oily, yellow liquids, insoluble in water, and maybe
distilled without decomposition. Alkalis and acids are usually without effect
upon them ; with phenol and sulphuric acid they give the nitroso-reaction.
When reduced in alcoholic solution by means of zinc dust and acetic acid they
become converted into hydrazines (p. 169). Boiling hydrochloric acid decom-
poses them into nitrous acid, and dialkylamines.
Dimethyl Nitrosamine, Nitrosodimethyline, (CH8)2N.NO, b.p. 148°.
Dtethyl Nitrosamine, Nitrosodiethyline, b.p. 177°.
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 169
(k) Nitramines
are produced by the action of concentrated nitric acid on various amide de-
rivatives of the primary amines, e.g. their urethanes or oxamides, from which
the free mono-alkyl nitramines may be obtained by splitting off ammonia
(B. 18, R. 146 ; 22, R. 295 ; C. 1898, I. 373) :
CH3NHCO2CH, ^ CH3N(NO2)C02CH3 >- CH3NH.NO,
or CH8N:NOOH.
One hydrogen atom in the monoalkyl nitramine molecule is replaceable by an
alkali metal, rendering the second formula RN : NOOH the more probably
correct. As in the alkali salts of the nitroparamns (p. 149) the metal is united to
an oxygen atom forming a compound of the type RN : NOOMe. By the reaction of
the potassium alkyl nitramines with the haloid alkyl compounds, there are pro-
duced the corresponding dialkyl nitramines, which yield unsym.-dialkyl hydrazines
by reduction with zinc dust and acetic acid.
Methyl Nitramine CH3NH.NOa, m.p. 38°. Ethyl Nitramine, m.p. 3°. Potas-
sium ethyl nitramine and iodomethane yield N-methyl ethyl nitramine (see below).
Propyl Nitramine, b.p.40 128°. 0-Methyl Ethyl Isonitramine, C?H6.N : NOaCH3,
k-P-20 37° (C. 1898, I. 374), is prepared from silver ethyl nitramine. Butyl
Nitramine, see B. 28, R. 1058.
Simple N-Dialkyl Nitramines : Dimethyl Nitramine, (CH3)aN.NOa, m.p. 58°,
b.p. 187°, is produced, together with an isomer, b.p. 112°, by the distillation of
monomethyl nitramine (B. 29, R. 910), as well as upon treating dimethylamine
and nitric acid with acetic anhydride (B. 28, 402), from monomethyl nitramine
and potassium nitrite (C. 1898, II. 477), and with diazomethane (B. 30,
646). Diethyl Nitramine, b.p. 206°. Dipropyl Nitramine, b.p. 77°. Mixed
Nitramines : Methyl Ethyl Nitramine, b.p. 190°. Methyl Propyl Nitramine, b.p.
115°. Methyl Butyl Nitramine, m.p. +0-5° (B. 29, R. 424). Methyl Allyl Nilra-
mine, b.p.18, 95°, is obtained, together with an isomer, b.p.18 51°, by the inter-
action of potassium methyl nitramine and allyl bromide.
The alkyl hydrazines, alkyl diazo-compounds, alkylazides, and
diazoamino paraffins (sections /, m, n, o), form classes of substances
analogous to those which were first prepared and investigated in the
aromatic series of organic compounds, where they exercised a great
influence on the development of that section of chemistry (Vol. II.).
The analogy is seen in the following comparative lists : —
Methyl Hydrazine . . CH3NH.NHa C6H6.NH.NHa Phenyl Hydrazine.
!C6H5.NC1 : N Diazobenzene Chloride.
C6H6N : NOK Potassium Diazoben-
zene.
/N /N
Methylazide . . . CH3N< || C6H6N< || Phenyl Diazoimide.
XN XN
Diazoaminomethane . CH3N:N.NHCH3 C.H6N:N.NCeH6
Diazoaminobenzene.
(I) Alkyl Hydrazines
Just as the amines are derived from ammonia, so the hydrazines
are derived from hydrazine or diamide, H2N.NH2, which can itself be
obtained by the splitting up of diazoacetic acid (q.v.) or amino-
guanidine (q.v.).
(i) If iodomethane acts on a cold aqueous solution of hydrazine, there are
formed monomethyl hydrazine and unsym.-dimethyl hydrazine ; with an excess
I7o ORGANIC CHEMISTRY
of iodomethane in the presence of alkalis, the final product is trimethyl hydra-
zonium iodide (B. 31, 56) :
NH2.NH, -^> NHa.NHCH3 -^V NH2.N(CH 3) 2 -^V NH ,.N (CH3) 3I.
Monoalkyl hydrazines also result by the heating of salts of alkyl sulphuric acid
with an aqueous solution of hydrazine (B. 34, 3268).
(2) Mono-alkyl and sym.-dialkyl urea, acted on by nitrous acid, give rise to
nitroso-compounds which in turn yield hydrazine derivatives of urea (alkyl
semicarbazides) on reduction. These are decomposed by boiling with alkalis or
acids into alkylamine, COa and monoalkyl hydrazine :
CH3NH.CO HNOa CH3NH.CO H ^CH3NH.CO Hao CH3NH2+CO2
CH8NH~ CH8N.NO CH3N.NH2 +CH3NH.NH2.
(3) unsym.-Dialkyl Hydrazines, on reduction with zinc dust and acetic acid,
yield dialkyl nitrosamines (p. 168) or dialkyl nitramines (B. 29, R. 424) :
(CH8)aN.NO+4H = (CH3)aN.NHa+H20.
Monoalkyl hydrazines are also obtained by reduction of the monoalkyl nitra-
mines (p. i6< ).
(40) sym. -Dialkyl Hydrazines are formed by the action of iodoalkyls on the
lead or potassium salts of diformyl hydrazine, CHO.NH.NH.CHO, and the sub-
sequent hydrolysis of the diformyl compound (B. 27, 2279 ; 31, 62 ; 39, 326*-).
(46) Further, by heating pyrazole or pyrazolon (Vol. II.) with iodoalkyls and
decomposing the resulting alkyl pyrazole iodoalkylate with aqueous potassium
hydroxide (B. 39, 3257, 3267) :
^CH=N(CH3)I KOH HNCH,
"^CH . NCH8 HNCH8
The mono-alkyl hydrazines reduce Fehling's solution in the cold, and the
dialkyl hydrazines when warmed. This behaviour differentiates them from the
amines, which they otherwise resemble closely.
Methyl Hydrazine, CH,.NH.NH2, b.p. 87°, is a very mobile liquid. Its odour
is like that of methylamine. It absorbs moisture and fumes in the pjr (B. 22,
R. 670).
Ethyl Hydrazine, (CaH6)HN.NH2, b.p. 100°.
When ethyl hydrazine is acted on by potassium pyrosulphate, potassium
ethyl hydrazine sulphonate, C2H8.NH — NH.SO3K, is formed. Mercuric oxide
changes this to potassium diazoethyl sulphonate, C2H6.N=N.SO3K.
sym.-Dimethyl Hydrazine, CH8NH.NHCH3, b.p. 81°, forms salts with mono-
and di-ba'sic acids. sym.-Diethyl Hydrazine, b.p. 85°.
unsym.-Dimethyl Hydrazine, (CH8)2N.NH2, b.p. 62°, and unsym.-Diethyl
Hydrazine, b.p. 97°, are mobile liquids, possessing an ammoniacal odour ; they are
soluble in water, alcohol and ether. Thionyl Diethyl Hydrazine, (C2H6)2N.N : SO,
b.p.2073°(B. 26, 310).
Trimethyl Hydrazonium Iodide, NH2.N(CH3)8I, m.p. 235°, with decomposition,
resembles tetramethyl ammonium iodide. Moist silver oxide liberates the
strongly alkaline tetramethyl hydrazonium hydroxide, NH2N(CH3)3OH ; this
consists of hydroscopic crystals, which are partially decomposed on distillation
into unsym.-dimethyl hydrazine and methyl alcohol. Heating with iodomethane
breaks down the molecule into tetramethyl ammonium iodide, nitrogen, and
hydrogen. Tetraethyl Hydrazonium Iodide is prepared from diethyl hydrazine
and iodoethane (A. 199, 318 ; B. 31, 57).
(m) Alkyl Diazo-Compounds
Potassium Diazoethane Sulphonate, C2H6N=N.SO8K (q.v.), obtained from
potassium ethyl hydrazine sulphonate, and the potassium salt of diazomethang
ALKYLAMINES AND ALKYL AMMONIUM DERIVATIVES 171
or methyl azoic acid (CH3N=N. OK), prepared from diazomethane (p. 213) are
two representatives of this class of compounds.
(n) Alkyl Diazoimides
Methyl Diazoimide, Methylazide, CH3.N3, b.p. 20°, D?5=o-869, is the methyl
ester of hydrazoic acid, and is obtained from the sodium hydrozoate NaN8 and
dimethyl sulphate in alkaline solution. It explodes violently above 500° (B. 38,
1573).
(o) Diazoamino Paraffins
Diazoatnino-methane, Dimethyl Triaxene, CH3N : N.NHCH,, m.p. —12°,
b.p. 93°, is a colourless liquid, having an odour resembling alkaloids. It is
poisonous, it dissolves in water, and explodes violently on sudden heating. Its
magnesium salt is produced from methyl azide and methyl magnesium iodide :
/N
CH3N<J| +CH,MgI=CHsN(MgI)N:NCH8.
This substance is decomposed by water.
The silver compound CH3N8.NAgCH3 exists as colourless needles, and the
copper compound CH8N2.NCu(CH8) as yellow crystals (B. 39, 3905). Diazo-
amino methane is very easily decomposed by acids, evolving nitrogen and splitting
into methylamine and a methyl ester :
CH,N:NHCH3+2HCl=CH,Cl+N2CH3NHa.HCl.
(p) Tetra-alkyl Tetrazones
When mercuric oxide acts on unsym.-diethyl nydrazine, (C2H6)2N.NH2,
tetraethyl tetrazone, (C2H5)2N.N : N.N(C2H6)2, is formed. This is a strongly
basic liquid with an alliaceous odour.
Methyl Butyl Tetrazone, b.p.19 121° (B. 29, R. 424).
(q) Alkyl Hydroxylamines
The entry of one alkyl group into hydroxylamine produces two isomeric
forms :
NH2.O.CH8 and CH3.NH.OH.
a-Methyl-hydroxylamine. /3-Methyl-hydroxylamlne.
The derivatives of both varieties are obtained from the isomeric benzaldoximes
(q.v.). The /^-compounds are formed from syn-meta-nitrobenzaldoxime by
alkylization with sodium alcoholate and an iodoalkyl, together with the subse-
quent separation of the ether by means of concentrated hydrochloric acid (B. 23,
599 ; 26, 2377, 2514). a-Derivatives result from the breaking down of alkyl benz-
hydroxamic esters. The j8-compounds are intermediate products in the reduction
of the nitre-paraffins with stannous chloride, or, better, with zinc dust and water
(B. 27, 1350), and can also be prepared by electrolytic reduction (C. 1899, II. 200).
jS- Alkyl hydroxylamines also occur as intermediate products during the oxidation
of primary amines with permonosulphuric acid, H2SO6, but they are mainly
oxidized further to aldoximes, hydroxamic acids, ketoximes, nitroso- and nitro-
compounds (p. 164).
Alkylation of hydroxylamine results essentially in the formation of /?-dialkyl
hydroxylamines, which in turn lead to the formation of the hydriodic acid salts of
the trialkylamine oxides (p. 172).
j3-Dialkyl hydroxylamines are also formed during the oxidation of the dialkyl-
amines (B. 34, 2499). They further result by treatment with water of the re-
action products of zinc alkyls or zinc or magnesium alkyl halides on alkyl nitrites,
nitro-paraffins (J. pr. Ch. [2] 63, 94, 193 ; B. 40, 3065) and diphenyl nitrosamine
(B. 33, 1022). During the course of the last three reactions the following
172 ORGANIC CHEMISTRY
intermediate products are probably formed, if we take as examples ethyl
nitrite, nitroethane (in the acid form) and diphenyl nitrosamine with zinc ethyl :
C2H6ZnOv
0:NOC2H6 2Zn(C^H^-> >N.CaH6+C2H6ZnOC2H8.
C2H/
7 ,r „ . CaH6ZnOv /CH3
HOON=CHCH3 2Zn(C2Hs)2-> >N-CH<( +CaH.+ZnO.
f^ TT / \/~> TJ
C2H6 ^-2H5
0:N.N(C8H8)a -Zn(C«H»)' ->
C,H/
jS-Dialkyl hydroxylamines are conveniently prepared by the action of nitric
oxide on magnesium alkyl iodides in solution in ether (B. 36, 2315).
2NO2+4CaH6MgI - > 2(C2H6)2NOMgI+MgO-f Mgl,.
Reduction changes the /?-dialkyl hydroxylamines into dialkylamines : when
sulphurous acid is employed they are converted into dialkyl sulphaminic acids
(B. 33, 159). See further under Trialkylamine oxides.
a-M ethyl Hydroxylamine, Methoxylamine, NH2.O.CH3, yields a hydro-
chloride, m.p. 149°. It differs from hydroxylamine in that it does not reduce
alkaline copper solutions.
a-Ethyl Hydroxylamine, Ethoxylamine, NH2.O.C2H6, b.p. 68°.
p-Mcthyl Hydroxylamine, CH8.NH.OH, m.p. 41°, b.p.ia 61° (B. 23, 3597 ',
24,3528; 25,1716; 26,2514).
fi-Ethyl Hydroxylamine, m.p. 59°.
p-Diethyl Hydroxylamine (CaH6)aN.OH, b.p.36 76°.
fi-Dipropyl Hydroxylamine, (C3H7)aN.OH, m.p. 29°, b.p. 150°.
Ethyl-sec. Butyl Hydroxylamine, CaH6N(OH)CH.(CH3).CaH5, b.p. 155°,
prepared from nitroethane and zinc ethyl, was previously thought to be triethyl-
amine oxide (C. 1901, I. 1146 ; II. 185).
a ft-Diethyl Hydroxylamine, C2H6NHOC2H6, b.p. 83°, and Triethyl Hydroxyl-
amine, (CaH6)2NOC2H5, b.p. 98°, are formed by the action of C2H6Br on ethoxyl-
amine (B. 22, R. 590).
(r) Trialkylamine Oxides
OT-T
These are obtained as salts of hydriodic acid, R3N<j by the action of iodo-
alkyls on hydroxylamine and the intermediate /?-dialkyl hydroxylamines ; also
by oxidation of the trialkylamines by HaOa (B. 34, 2499). The free oxide is un-
known, but the corresponding hydrate, a deliquescent body, has been obtained,
as in the case of the hydrate of Triethylamine Oxide Hydrate, (C2H6) 8N(OH) ,. The
trialkylamine residue plays a similar part to that of a metal of the alkali earths in
the corresponding hydroxides. The trimethyl compound is decomposed by heat
into dimethylamine and formaldehyde, whilst the Tripropylamine Oxide Hydrate is
broken up into jS-dipropyl hydroxylamine and propylene. Sulphurous acid
converts it into tripropylamine when heated ; in the cold it forms an addition
product (C8H7)3N<^ | , m.p. 159°, which is deposited as tiny crystals possessing
a silky sheen (B. 34, 2501).
(s) Nitroso-j8-alkyl Hydroxylamines
A member of this class of bodies was probably discovered by Frankland, and
described under the name of Dinitro ethylic acid. It is prepared by the action
of NO on zinc ethyl and the subsequent decomposition by water of the addition
compound formed, and is designated as nitroso-B-ethyl hydroxylamine (B. 33,
1024) :
NO , NO
/
CH8CH2N< - > CH3CH2N
X)H
PHOSPHORUS DERIVATIVES OF ALCOHOL RADICALS 173
Similarly a salt of nitroso- ^-methyl hydroxylamine is prepared from NO —
which reacts according to the constitutional formula O : H — N:O — and magnesium
methyl iodide in solution in ether :
2NO+CH8MgI=CH8N<
NO
OMgl
which gives the Liebermann nitroso-reaction, and yields a well crystallized copper
salt, (CH3N2O2)2Cu+JH2O.
6. PHOSPHORUS DERIVATIVES OF THE ALCOHOL RADICALS
A. PHOSPHORUS BASES OR PHOSPHINES AND ALKYL
PHOSPHONIUM COMPOUNDS
Hydrogen phosphide, PH3, has slight basic properties. It unites
with HI to form phosphonium iodide, which is resolved again by water
into its components. The phosphorus bases or phosphines, obtained
by the replacement of the hydrogen of PH3 by alkyls, have more of
the basic character of ammonia and approach the amines in this
respect. The basic character increases with the number of alkyl
groups.
(i) They are oxidized very energetically on exposure to the atmo-
sphere, usually with spontaneous ignition ; hence they must be prepared
in the absence of air. Moderate oxidation with nitric acid converts
the primary phosphines into alkyl phosphoric acids, the secondary
phosphines into alkyl phospho- acids, whilst the tertiary phosphines,
in the presence of air, pass into alkyl phosphinic oxides :
Ethyl Phosphine : CaH,PH2 >- C2H6PO (OH) 2— Ethyl Phosphoric Acid.
Diethyl Phosphine : (C2IiJ2PH >- (C2H6)2PO(OH)— Diethyl Phosphinic Acid.
Triethyl Phosphine : (C2H6),P >- (C2H6)8PO— Triethyl Phosphine Oxide.
(2) They combine readily with sulphur and carbon disulphide (B. 25, 2436) ;
also with the halogens.
(3) The primary phosphines, are, like PH8, feeble bases. Their salts, such
as PH4I, are decomposed by water. Potassium hydroxide is required for the
decomposition of the salts of the secondary and tertiary phosphines.
(4) The tertiary phosphines combine with the alkyl iodides to form tetra-
alkyl phosphonium iodides. These are just as little decomposed by potassium
hydroxide as the tetra-alkyl ammonium iodides. Moist silver oxide liberates tetra-
alkyl phosphonium hydroxides from them ; these, like the tetra-alkyl ammonium
hydroxides, are stronger bases than the alkalis :
P(CH8)8-^1-->P(CH8)4I -Ag-^L-> P(CH8)4OH.
Thtnard (1846) discovered the tertiary phosphines, and A. W. Hofmann (1871)
first prepared the primary and secondary phosphines (B. 4, 430).
Formation. — (i) By the reaction between alkyl iodides and phosphonium
iodide for six hours in the presence of certain metallic oxides, chiefly zinc oxide,
at 150°. The product, in the case of ethyl iodide, is a mixture of P(C8H6)H2.HI
and P(C2H6)aH.HI, the first of which is decomposed by water. The HI -salt of
the diethyl phosphine is not affected, but by boiling the latter with sodium
hydroxide, diethyl phosphine is set free (A . W. Hofmann) :
2PH4I+2C,H6I+ZnO==2[P(C2H6)H2.HI]+ZnIa+HtO.
PH4I+2C2H6I-fZnO=P(C2H6)2H.HI -f-ZnIt+H,O.
P(C,H,)H2HI — -5^
I74 ORGANIC CHEMISTRY
(2) Tertiary phosphines and phpsphonium iodides are produced by heating
phosphonium iodide with alkyl iodides (methyl iodide) to 150-180° without the
addition of metallic oxides. They can be separated by means of potassium
hydroxide :
PH4I+3CH3I=P(CH3)3.HI+3HI.
P(CH3)8HI+CH8I =P(CH3)4.I
(3) Tertiary phosphines result when alkylogens act on calcium phosphide
(Thdnard), and (4) in the action of zinc alkyls on phosphorus chloride :
2PCls+3Zn(CH8)a=2P(CH3)8+3ZnClr
(Compare the action of mercury alkyls on PC13, p. 175.)
(4) Primary phosphines are also obtained by heating monoalkyl phosphinous
acids (p. 175).
The phosphines are colourless, strongly refracting, extremely powerful-smelling,
volatile liquids. They are scarcely soluble in water, but dissolve readily in
alcohol and ether. They oxidize very readily and have a neutral reaction.
(1) Primary Phosphines :
Methyl Phosphine, P(CH3)H2, condenses at —14° to a mobile liquid.
Ethyl Phosphine, P(C2H6)H2, b.p. 25°.
n-Propyl Phosphine, P(C3H7)H2, b.p. 53° (C. 1903, II, 987).
Isopropyl Phosphine, P(C8H7)H2, b.p. 41°, Isobutyl Phosphine, P(C4H7)H2,
b.p. 62°. Fuming nitric acid oxidizes the primary phosphines to alkyl phospho-
acids ; their Hi-salts are decomposed by water.
(2) Secondary Phssphines :
Dimethyl Phosphine, P(CH3)2H, b.p. 25° C.
Diethyl Phosphine, P(C2H6)2H, b.p. 85°.
Diisopropyl Phosphine, P(C3H7)2H, b.p. 118°. Diisoamyl Phosphine,
P(C6Hn)2H, b.p. 210-215°, is not spontaneously inflammable. Fuming nitric
acid oxidizes this class of phosphines to dialkyl phosphinic acids.
Water does not decompose the Hi-salts of the secondary phosphines.
(3) Tertiary Phosphines :
Trimethyl Phosphine, P(CH3),, b.p. 40°. Triethyl Phosphine, P(C2H5)3, b.p.
127°. Both tertiary phosphines form phosphine oxides by the absorption of
oxygen (B. 29, 1707). They also combine with S, C12, Br2, the halogen acids,
and the alkylogens. Carbon disulphide also combines with triethyl phosphine, and
the product is P(C2H6)3.CS3, b.p. 95°, crystallizing in red leaflets. It is insoluble
in water, and sublimes without decomposition. Its production serves for the
detection of carbon disulphide.
According to almost all of these reactions, triethyl phosphine resembles a
strongly positive bivalent metal — for example, calcium. By the addition of three
alkyl groups, the quinquivalent, metalloidal phosphorus atom acquires the
character of a bivalent alkali-earth metal. By the further addition of an alkyl
group to the phosphorus in the phosphonium group, P(CH,)4, the former acquires
the properties of a univalent alkali metal. Similar conditions are to be observed
with sulphur, tellurium, arsenic, and also with almost all the less positive
metals.
(4) Phosphonium Bases. — The tetra-alkyl phosphonium bases resemble, in a
very high degree, both in formation and properties, the tetra-alkyl ammonium
bases. Tetramethyl- and Tetraethyl phosphonium hydroxide, P(C2HB)4.OH, are
crystalline masses which deliquesce on exposure to the air. They possess a
strongly alkaline reaction. When they are heated they show the great affinity of
phosphorus for oxygen, for, unlike the corresponding ammonium derivatives, they
break down into a trialkyl phosphine oxide and a paraffin. Thus tetramethyl
phosphonium hydroxide yields trimethyl phosphine oxide and methane :
P(CH8)4.OH=P(CH8),O-f-CH4.
Tetramethyl- and Tetraethyl Phosphonium Iodide, P(C2H5)4I, are white, crystal-
line substances, which are decomposed by heat into trialkyl phosphines and alkyl
iodides. Tetraethyl phosphonium periodide results from the prolonged inter-
action of iodoethane and phosphorus at 180°. With H.S it changes into the
normal iodide (B. 22, R. 34 8)
ARSENIC ALKYL COMPOUNDS 175
B. ALKYL PHOSPHO-ACIDS
These acids result, as mentioned previously, from the moderated oxidation, of
the primary phosphines with nitric acid ; and also by oxidation of mono-alkyl
phospho-acids (see below). They are derived from unsymmetrical phosphorous
acid, HPO(OH)2.
Methyl Phospho-acid, CH3PO(OH)2, m.p. 105°. PC16 converts it into
the chloride, CH3POC12, m.p. 32°, b.p. 163°. On the formation of similar
chlorides from alkyl-tetrachlorophosphines, see below. Ethyl Phospho acid,
CaH6PO(9H)2,m.p.'440.
The dialkyl esters of alkyl phospho acid, e.g. Diethyl Ester of Propyl Phospho -
acid, C8H7PO(OC2Hfi)2, b.p.8.6 87°, are obtained from the addition products of
sym. -phosphorous acid ester (p. 141) and alkyl iodides (C. 1906, II. 1640 ; B. 31,
1048), and from the interaction of alkyl oxychlorophosphines (see below) and
sodium alcoholates.
C. ALKYL PHOSPHINIC ACIDS
These are derived from hypophosphorous acid, H2PO(OH).
(1) Mono-alkyl Phosphiaic Acids.
The action of mercury alkyls on PC18 results in the formation of alkyl chloro-
phosphines :
(C2H6)aHg+PCl8=C2H5HgCl+C2H6PCl2.
Ethyl Chlorophosphine, b.p. 114-117°, 0,9 = 1*295. Propyl Chlorophosphine,
b.p. 140-143°, Di9 = ri77. Isoamyl Chlorophosphine, b.p. 180-183°, D?3=i'io2.
Water decomposes these chlorides into the corresponding alkyl phosphinic acids.
RPO2H2. They are syrupy liquids which are decomposed into alkyl phosphines
and alkyl phospho acids when heated :
3C5HnP01H1=C8H11PH1+2C8H11FO,Ht
Chlorine combines with the alkyl chlorophosphines forming alkyl tetrachioro-
phosphines, RPC14, which resemble phosphorus pentachloride. Heat causes
partial dissociation into PC18 and chloro-alkyl ; SO2 produces thionyl chloride and
alkyl oxychlorophosphines, RPOC12; ethyl oxy Chlorophosphine, b.p.M 75-80°;
propyl oxychlorophosphine, b.p.60 88-90°.
The alkyl chlorophosphines heated with sulphur form alkyl sulphochloro-
phosphines,~'RPSCl2 ; ethyl sulphochlorophosphine, b.p.50 81° (B. 32, 1572).
(2) Dialkyl Phosphinic Acids result from oxidation of secondary phosphines
by fuming nitric acid. Dimethyl Phosphinic Acid, (CH2)2 PO(OH), m.p. 76°, forms
a paraffin-like mass, which volatilizes undecomposed. Diethyl Dithiophosphinic
Acid, (C8H5)2PS.SH, see B. 25, 2441.
D. ALKYL PHOSPHINE OXIDES
arise (i) when the tri-alkyl phosphines are oxidized in the air, together with
alkyl esters of dialkyl phosphinic acid, R2PO2R, and alkyl phospho acids, RPO8Ra
(B. 31, 3055), or by mercuric oxide; (2) in the decomposition of the tetra-alkyl
phosphonium hydroxides by heat ; (3) from POC1, and magnesium alkyl haloids :
POC1 8 -f- 3 RMgX = OPR, + sMgXCl.
The trialkyl phosphine oxides combine with acids similarly to the trialkylamine
oxides (p. 172) (C. 1906, I. 1484). Triethyl Phosphine Oxide, P(C8H6)3O, m.p.
53°, b.p. 243°, forms, for example, P(C2H5)3C12, with haloid acids, from which
sodium regenerates triethyl phosphine by the aid of heat. The corresponding
triethyl phosphine sulphide, P(C2H6)3S, m.p. 94°, is prepared from triethyl
phosphine and sulphur.
7, ALKYL DERIVATIVES OF ARSENIC
Arsenic is somewhat metallic in character ; its alkyl compounds
constitute the transition from the nitrogen and phosphorus bases to
176 ORGANIC CHEMISTRY
the so-called metalloorganic derivatives — i.e. the compounds of the
alkyls with the true metals (p. 183). The similarity to the amines and
phosphines is observed in the existence of tertiary arsines, As(CH8)3,
but these do not possess basic properties, nor do they unite with
acids. They show in a marked degree the property of the tertiary
phosphines, in their uniting with oxygen, sulphur, and the halogens
to form compounds of the type As(CH3)3X2, and with halogen alkyls
to form quaternary arsonium compounds As(CH3}4X. The mono-,
di-, and tri-alkyl arsines, derived from AsH3, have not played nearly
as important a rdle in the development of organic chemistry as have
the cacodyl compounds.
In 1760 Cadet discovered the reaction which led to the study of the arsenic
alkyls. He distilled arsenious acid together with potassium acetate, and obtained
a liquid which was subsequently named, after its discoverer, Cadet's fuming
arsenical liquid. From 1837 to 1843 Bunsen carried out a series of splendid investi-
gations (A. 37, i ; 42, 14 ; 46, i), and demonstrated that the chief constituent of
Cadet's liquid was " alkarsine," or cacodyl oxide, whose radical " cacodyl " Bunsen
also succeeded in preparing. Berzelius proposed the name cacodyl (from Ka.K<a8r]st
stinking) for this very poisonous body with an extremely repulsive odour.
Bunsen showed that it behaved like a compound radical. Together with tbe
cyanogen of Gay-Lussac, and the benzoyl of Liebig and Wohler, which was assumed
to be present in the benzoyl derivatives, it formed a strong support for the radical
theory. But later it was found that cacodyl was no more a free radical than was
cyanogen, but that, in accordance with the doctrine of valence, it was rather a
compound of two univalent radicals — As(CHs)., combined to a saturated mole-
As(CH8),
cule : |
As(CH8)2.
Valuable contributions have been made to the chemistry of the arsenic alkyls
by Cahours and Riche (A. 92, 361), by Landolt (A. 92, 370), and particularly by
Baeyer, who discovered the monomethyl arsenic derivatives, and made clear the
connection existing between the alkyl-arsenic derivatives (A. 107, 257).
The following reactions give rise to arsenic alkyl compounds : —
(1) Cacodyl Oxide, or Alkarsine, is produced by the distillation of
potassium acetate and arsenious acid. This is a delicate test, both
for arsenic and for acetic acid :
4CH,.CO,K-fAs1Oa=[(CH8)aAs],0+2KaCO,+2CO1.
(2) Also, by the action of zinc alkyls on arsenic trichloride ; and
(3) by the action of the alkyl iodides on sodium arsenide produces
trialkarsine together with tetra-alkyl diarsine (ethyl cacodyl).
2AsCl8+3Zn(CH8)2=2As(CH8)8+3ZnC],.
AsNa,+3C2H5I «=As(CaH6),+ 3NaI.
(4) The interaction of trisodium or tripotassium arsenite and alkyl
iodides gives rise to the sodium salts of alkyl arsonic acid (A. 249, 147 ;
C. 1905, I. 860), which reaction is similar to that of the formation
of alkyl sulphonic acid salts from potassium sulphite and iodoalkyls
(p. 146).
K3AsO8+CHsI=CH8AsO(OK)2+KI.
The method for alkylating arsenic can be pushed further for the production of
di- and tri-alkyl compounds. Methyl arsenic oxide, obtained from methyl
arsenic acid by reduction with SOa (see below), yields cacodylic acid or dimethyl
arsenious acid by the action of iodomethane and alkalis :
MONOALKYL-ARSINE COMPOUNDS 177
Cacodyl oxide, obtained by reduction of cacodyhc acid, or from arsenic direct
gives trimethyl arsenic oxide, when treated with iodomethane and alkali (C. 1904,
I. 80):
(CH8)aAsOH+KOH+CH8I
MONOALKYL-ARSINE COMPOUNDS
The formation of monomethyl arsenic chloride, As(CH8)Cl2, results from the
property possessed by the derivatives of the type AsX8, of adding two halogen
atoms (C12) and passing into compounds of the form AsX5. The more chlorine
atoms these bodies contain, the more readily do they split off methyl chloride.
Thus As(CH3)Cl4 breaks down, at o°, into AsCU and CH3C1; and As(CHa)2Cla
at 50°, into As(CHa)Cla and CH8C1 :
+cia
As(CH3)3 -- > As(CH,)3Cla - > CH8Cl+As(CH8)aCl
+ Cla 50°
As(CH3)aCl - > As(CH3)aCl8 - > CH3Cl+As(CH8)Cl,
+ Cl« o*
As(CH3)Cla - > As(CH3)Cl4 - > CH3Cl+AsCl3.
These reactions are the reverse of those described (method no. 4) for the pro-
gressive elaboration of methyl-arsenic compounds from arsenic.
Methyl Arsine Dichloride, CH3AsCl2, b.p. 133°, results from cacodyl
trichloride, (CH3),AsCl8 (see above), or cacodylic acid by the action of HC1, also
from methyl arsenic acid (see below) and an excess of PC18 (C. 1906, II. 101).
It is a heavy, water-soluble liquid. Similarly, Methyl Arsine Diiodide, CH,AsI2,
is obtained from methyl arsenic acid by reduction by SO2, followed by precipi-
tation with HI. The methyl arsine dihalide yields Methyl Arsenoxide, CH8AsO,
m.p. 95°, by the action of Na2CO8 ; with HaS is formed Methyl Arsine Sulphide,
CH8AsS, m.p. 110°; and with Ag2O the silver salt of methyl arsenic acid is
obtained.
Methyl Arsenic Acid, CH8AsO(OH)2, m.p. 161°, and Ethyl Arsenic Acid,
C2H5AsO(OH)2, are best prepared from potassium arsenite and iodoalkyls in
aqueous solution (see above) ; boiling magnesia mixture precipitates the mag-
nesium salt (C. 1905, 1. 800). The sodium salt of methyl arsenic acid is employed
medicinally under the name of Arrhenal (comp. G. 1905, I. 1699). Reduction
of methyl and ethyl arsenic acids with hypophosphite in a sulphuric acid solution
leads to the formation of Methyl and Ethyl Arsenic (CH3As)xand (C2H6As)a. as
yellow easily polymerisable oils (C. 1904, II. 415 ; 1906, I. 730).
Methyl Arsine, CH3AsHa, b.p. +2°, and Ethyl Arsine, C2H5AsH2, b.p. 36°,
result from reduction of the alkyl arsenic acids by amalgamated zinc dust, alcohol,
and hydrochloric acid. They are colourless liquids of a cacodyl-like odour,
very poisonous, and form salts with acids with great difficulty or not at all.
Methyl arsine is not spontaneously inflammable. Oxidation leads first to methyl
arsenoxide and then to methyl arsenic acid ; iodoalkyls give rise to the alkyl-
arsines, e.g. tetraalkyl arsonium iodide (B. 34, 3594 ; C. 1905, I. 799).
DIALKYL ARSINE DERIVATIVES
Cacodylic Oxide, Alkarsine, CHAS>°* m-P- ~25°» b-P- I20°>
D16= 1-462, is the parent substance for the preparation of the
dimethyl compounds. Its formation from potassium acetate and
arsenic trioxide has already been given on p. 176. The crude oxide
ignites spontaneously in the air. This is due to the presence in it of
a slight amount of free cacodyl. When prepared from cacodyl
chloride by potassium hydroxide it does not inflame spontaneously,
and consists of a liquid with a stupefying odour. It is insoluble in
water, but readily soluble in alcohol and in ether.
Dimethyl Arsine, Cacodyl Hydride, (CH3)2AsH, b.p. 36°, D29=i'2i3,
is produced when zinc and hydrochloric acid act on cacodyl
VOL. I. N
178 ORGANIC CHEMISTRY
chloride in alcoholic solution. It is a colourless, mobile liquid, with
the characteristic cacodyl odour, and inflames spontaneously in the
air. It combines with acids to form very easily dissociated salts ;
the halogen acid salts decompose into hydrogen and cacodyl chloride,
bromide or iodide. With iodoalkyls it forms tetraalkyl arsonium
iodides. It unites with sulphur, producing cacodyl disulphide,
[(CH8)2As]2S2, m.p. 50°, and cacodyl sulphide. [(CH^gAsJgS, b.p. 211°.
Oxidation produces cacodyl, cacodyl oxide, cacodylic acid, As2O3,CO2,
etc., according to the degree of action (B. 27, 1378 ; C. 1906, I. 738).
Cacodyl Chloride, As(CHs)aCl, b.p. 100°, is formed by heating trimethyl-
arsine dichloride, As(CH8)3Cl2 (p. 177), and by acting on cacodyl oxide
with hydrochloric acid, as well as from C12 and cacodyl. It is more readily
obtained by heating the mercuric chloride compound of the oxide with hydro-
chloric acid. It unites with chlorine to form the trichloride, As(CH8)2Cla, which
renders possible the transition from the dimethyl compounds to the monomethyl
derivatives.
Cacodyl Cyanide, As(CH8)2.CN, m.p. 36°, b.p. 140°, is formed by heating
cacodyl chloride with mercuric cyanide.
Cacodylic Acid, (CH8)2AsO.OH, m.p. 200° with decomposition, corresponds
in its composition to dimethyl phosphinic acid (see p. 175). Cacodyl oxide,
by slow oxidation, passes into cacodyl cacodylate, which breaks down, when
distilled with water, into cacodylic oxide and cacodylic acid :
As(CH8)2, Q Q _ As(CH3)2
As(CH3)2>u ~ OAs(CH8)2>Ut
= [As(CH*)2]20+20As(CH8)2.OH.
It is also obtained by the action of mercuric oxide on cacodylic oxide. On
the formation of cacodylic acid from methyl arsenoxide, KOH, and iodomethane,
see method of formation 4, p. 177.
It is easily soluble in water and is colourless. Like arrhenal (p. 177) it is
employed pharmaceutically, but is more poisonous. Cacodylic acid forms salts
with bases KdO2Me and with acids KdOX — it is an amphoteric electrolyte (B. 37,
2705, 3625, 4140). With H2S it forms Cacodyl Sulphide, with HI Cacodyl Iodide,
(CH,)tAsI. PC15 changes it to Dimethyl Arsine Trichloride, (CH8)2AsCl8, from
which water regenerates cacodylic acid.
As(CHs)2
Cacodyl, Arsenic Dimethyl, As2(CH8)4 = I , m.p. —6°, b.p. 170*, is
As(CH8)2
formed by heating the chloride with zinc filings in an atmosphere of carbon
dioxide :
nxAs(CH3)2 2HC1 Cl.As(CH8)2 Zn As(CH8)2.
°<As(CH8)J -- > Cl.As(CH8)8 - > As(CH,)t.
It is a colourless liquid, insoluble in water. Its odour is powerful, and may
induce vomiting. Cacodyl takes fire very readily in the air and burns to As2O8,
carbon dioxide and water. It yields cacodyl chloride with chlorine, and the
sulphide with sulphur. Nitric acid converts it into a nitrate, As(CH3)aO.NOr
As(C2H5)a
Ethyl Cacodyl, \ , b.p. 185-190°, is formed together with triethyl
As(C2H6),
arsine on heating sodium arsenide with ethyl iodide. It takes fire in the air,
and is converted by oxidation into diethyl arsenic acid, (C2H5)2AsO.OH.
Diisoamyl Arsine Chloride, (C5Hn)2AsCl, is produced from isoamyl chloride,
arsenic trichloride, and sodium in ether. With H2S it changes to Diisoamyl
Arsine Sulphide, m.p. 30° ; with bromine water it forms Diisoamyl Arsinic Acid,
jC-sHnhAsOOH, m.p. 154° (C. 1906, I. 741). Diisoamyl Arsine, (C,Hn)2AsH,
b-P-»o I5° , results from the reduction of diisoamyl arsinic acid ; it is not spon-
taneously inflammable (C. 1906, I. 74).
ALKYI- COMPOUNDS OF BISMUTH 179
TERTIARY ARSINES
The tertiary arsines are formed by the action of the zinc alkyls on arsenic
trichloride, and by heating the alkyl iodides with sodium arsenide. Cacodyl,
formed simultaneously, is separated by fractional distillation.
Trimethyl Arsine (CH8)3As, and Triethyl AY sine, (C2H6)sAs, are liquids with a
very disagreeable odour. With oxygen they yield Trimethyl Arsenoxide (CH8)8AsO,
and Triethyl Arsenoxide, (C2H6)3AsO. These bodies correspond to triethylamine
oxide (p. 172) and trietkyl phosphine oxide (p. 173) ; with sulphur they yield
trimethyl and triethyl arsine sulphide, As(C,H5)3S; and with Br8 and Ia
they form trimethyl arsine bromide, As(CH3)3Br2, and triethyl arsine iodide,
As(C2H6)8I2.
QUATERNARY ALKYL ARSONIUM COMPOUNDS
Tetra-alkylarsonium iodide is obtained (i) from mono-, di-, or tri-alkyl
arsine by means of iodoalkyls ; (2) from sodium arsenide, mercury arsenide, or
powdered arsenic and iodoalkyls by the aid of heat (A. 341, 182 ; C. 1907, I,
152). Tetramethyl Arsonium Iodide, As(CH3)4I, and Tetraethyl Arsonium Iodide,
As(C2H6)4I, m.p. of both indefinite, are stable, and are of good crystalline form.
They correspond with the tetraalkyl ammonium and phosphonium iodides
(pp. 163, 174). Like them they are changed by moist silver oxide into the
hydrated oxides: Tetramethyl Arsonium Hydroxide, (As(CH3)4OH, and Tetraethyl
Arsonium Hydroxide, As(C2H6)4OH, are crystalline deliquescent bodies, possessing
a strongly alkaline reaction.
8. ALKYL DERIVATIVES OF ANTIMONY
The derivatives of antimony and the alkyls are perfectly analogous to those
of arsenic, but those containing one and two alkyl groups do not exist. We are
indebted to Lowig and to Landolt for our knowledge of them.
Tertiary Stibines are produced like the tertiary arsines :
(1) by the action of alkyl iodides on potassium or sodium antimonides ;
(2) by the interaction of zinc alkyls and antimony trichloride.
Trimethyl Stibine, Sb(CH3)3, b.p. 81°, D1B = 1-523, and Triethyl Stibine,
Sb(C2H6)3, b.p. 159°, are liquids which take fire in the air, and are insoluble in
water. In all their reactions they exhibit the character of a bivalent metal,
such as calcium or zinc. With oxygen, sulphur, and the halogens, they combine
energetically, and even decompose concentrated hydrochloric acid :
Sb(C2H6),+2HCl=Sb(C2H6)3Cla+H2.
Triethyl Stibine Oxide, Sb(C2H6)8O, is soluble in water, which is also true of
Triethyl Stibine Sulphide, Sb(C2H6)8S, which consists of shining crystals. Its
solution behaves somewhat like a calcium sulphide solution. It precipitates
sulphides from solutions of the heavy metals with the formation of salts of triethyl
stibine. Triethyl Stibine Chloride is also prepared from antimony pentachloride
and C2H6MgI. The iodide, m.p. 70° (B. 37, 320).
Quaternary Stibpnium Compounds, prepared from tertiary stibines by the
addition of alkyl iodides, are changed by moist silver oxide into tetra-alkyl stibonium
hydroxides. Tetramethyl and Tetraethyl Stibonium Iodide, Sb(C2H6)4I, as well as
Tetramethyl and Tetraethyl Stibonium Hydroxide, (C2H6)4SbOH, greatly resemble
the corresponding arsenic derivatives in their properties. For mercury double
salts with tetra-alkyl stibonium halides, see C. 1900, I. 1091.
9. ALKYL COMPOUNDS OF BISMUTH
These are closely comparable with those derived from antimony and arsenic ;
but in accordance with the more metallic nature of bismuth, no compounds
analogous to stibonium or arsonium are formed.
i8o ORGANIC CHEMISTRY
Further, in trialkyl derivatives the alkyl groups are less intimately united
with the bismuth than they are with arsenic and antimony in their corresponding
derivatives.
Tertiary Bismuthides result from (i) the action of alkyl iodides on potassium
bismuthide ; (2) the interaction of zinc alkyls and bismuth tribromide.
Bismuth Trimethyl, Bi(CH,)8, and Bismuth Triethyl, Bi(CaH,)8, are liquids
which can be distilled without decomposition under reduced pressure. They
explode when heated at the ordinary pressure (B. 20, 1516 ; 21, 2035) . Bismuth
trimethide is changed by hydrochloric acid to Bid, and methane. The tri-ethide
is spontaneously inflammable. It unites with iodine to Bismuth Diethyl Iodide,
Bi(C2H6)aI ; and reacts with mercuric chloride to form Bismuth Ethyl Bichloride,
Bi(C,H,)Cla:
Bi(CaH6)3+2HgCla=Bi(CaH$)Cla+2Hg(C1HB)Cl.
From the alcoholic solution of the iodide the alkalis precipitate Bismuth
Ethyl Oxide, Bi(C2H,)O, an amorphous, yellow powder, which takes fire readily
in the air. The nitrate, Bi(C,H4)<Q*NQa, is produced by adding silver nitrate
to the iodide.
10. ALKYL DERIVATIVES OF BORON
These are formed by the action of zinc alkyls on (i) boron trichloride,
(2) boric ethyl ester (p. 141) (Frankland, A. 124, 129) :
2B(OC2H6)3+3Zn(C2H6)a=2B(CzH6),4-3(C,H6.0)aZn.
Trimethyl Bovine is a gas.
Triethyl Bovine, B(C2H6)8, b.p. 95°. Both ignite in contact with the air and
possess an extremely penetrating odour. When heated together with hydro-
chloric acid, triethyi borine decomposes into diethyl borine chloride and ethane :
B(C2H6)8+HCl=B(C2H6)2Cl-fC2H,.
Slowly oxidized in the air, triethyi borine passes into Ethyl Boric Diethyl Ester,
B(C2H6)(O.C2H6)2, b.p. 125°, which water decomposes into Ethyl Boric Acid ,
CaH6.B(OH)a.
11. ALKYL DERIVATIVES OF SILICON
Silicon is the nearest analogue of carbon, to which its similarity is
specially close in its derivatives with the alcohol radicals, which in
many respects resemble the correspondingly constituted paraffins
(Friedel / Crafts ; Ladenburg, A. 203, 241). As early as 1863 Wohler
directed attention to the analogy existing between the carbon and
silicon compounds.
Silicon Tetramethyl, Si (CH3)4, corresponds with Tetramethyl Methane,
C(CH3)4.
Silicon Tetraethyl, Si(C2H6)4, corresponds with Tetraethyl Methane,
C(C2H6)4.
They are produced, like the alkyl borines, when zinc alkyls act on
(1) Silicon halogen compounds ;
(2) Esters of silicic acid.
(3) Also, silicon tetrachloride. and ethyl magnesium iodide or
bromide in ether give rise to a number of bodies according to the
quantity of the second reacting substance employed :
C.H.SiCl, ^ (C2H5)2SiClt > (C2H6),SiCl >• (C,HB)4Si.
Ethyl Silicon Diethyl Silicon Triethyl Silicon Tetraethyl
Trichloride. Dichloride. Chloride. Silicon.
GERMANIUM ALKYL DERIVATIVES 181
If ethyl silicon trichloride is acted on by other organo-magnesium
halides, mixed alkyl silicon compounds can be obtained, e.g. ClSi(C2H5)-
(C«HB)(CsH7) (C. 1904, 1. 636 ; 1907, 1. 1192).
(4) Silicon tetrachloride or silicon chloroform, chloro-alkyls, and
sodium in ether react to form alkyl silicon compounds :
SiCl4+4ClC,H,+8Na=Si(C1H8)4+8NaCl.
HSiCl,+3ClCiH11+6Na=HSi(C6H11),+6NaCl.
Silicon Tetramethyl, Si(CH3)4, b.p. 30°, D0=o*928, a liquid insoluble
in water, is prepared from SiCl4 and zinc methyl.
Silicon Tetraethyl, Silicononane, Si(C2H5)4, b.p. 153°, D0=o-834,
formed from SiQ4 and Zn(C2H5)2, or C2H5C1 and sodium, is a liquid
insoluble in water. By the action of chlorine, it forms silicononyl
chloride, a substitution product. Potassium acetate changes this to
the acetic ester of silicononyl alcohol, which alkalis decompose into
acetic acid and silicononyl alcohol :
t j, 2826 2625
Silicononane, Silicononyl Chloride, Silicononyl Alcohol,
b.p. 153°. b.p. 85°. b.p. 190°.
Silicon Tetraisoamyl, b.p. 275°. Silicon Triisoamyl Hydride Si(C6Hn)3H,
b.p. 245°, with bromine, passes into Silicon Triamyl Bromide, Si(C6H11)8Br, b.p.
279°, a heavy liquid, fuming in the air, which with ammonia gives Triamyl
Silicol, Si(C8Hu),OH, b.p. 270° (B. 38, 1665).
Disilicon Hexethyl, Si,(C8H,) „ b.p. 250-253°, is formed from zinc ethyl and Si2I6.
Triethyl Silicon Ethoxide, (C2H8),SiOC2H8, b.p. 153°.
Diethyl Silicon Diethoxide, (C2H,),Si(OC2H,)a, b.p. 155-8°.
Ethyl Silicon Triethoxide, (C2H,)Si(O.C2HB)3, b.p. 159°, is a liquid with a
camphor-like odour. These three compounds are produced when zinc ethyl
acts on silicic ethyl ester, Si(OC,H6)4 (p. 141).
Acetic anhydride converts triethyl silicon ethoxide into an acetic ester.
When this is hydrolyzed by potassium hydroxide, it yields Triethyl Silicon
Hydroxide or Triethyl Silicol, (CaH8),SiOH, corresponding in constitution with
Triethyl Carbinol.
Acetyl chloride changes diethyl silicon diethoxide into Diethyl Silicon Chloride,
(C2H8)2SiClt, b.p. 148°. Water converts this into Diethyl Silicon Oxide,
(C2H5j2SiO, corresponding with diethyl ketone in composition.
With acetyl chloride, ethyl silicon triethoxide forms Ethyl Silicon Trichloride,
(C2H,)SiCl,, b.p. about 100°. This liquid fumes strongly in the air, and when
treated with water passes into ethyl silicic acid, (C2H8)SiO.OH (silico-propionic
acid), which is analogous to propionic acid, C2H8.CO.OH, in constitution. It is
a white, amorphous powder, which becomes incandescent when heated in the
air. It only resembles the corresponding propionic acid by being acidic in
character.
(C2H8)3SiOH, Triethyl Silicol corresponds with (C2H6)3C.OH, Triethyl Carbinol.
(C2H8) 2SiO, Diethyl Silicon Oxide corresponds with (C2H6) 2CO, Diethyl Ketone.
C2H6.SiOOH, Silico-propionic Acid corresponds with CaH4.COOH, Propionic Acid.
12. ALKYL DERIVATIVES OF GERMANIUM
The compounds of germanium form the transition from those of silicon to
those of tin.
Germanium Ethyl, Ge(C2H6)4, b.p. 160°, is formed when zinc ethyl acts
on germanium chloride. It is a liquid with a leek-like odour. (Cl. Winklert
J.pr.Ch.[2]36,204.)
ORGANIC CHEMISTRY
13. TIN ALKYL COMPOUNDS
In addition to the saturated derivatives with four alkyls, tin is
also capable of uniting with three and two alkyls, forming :
Sn(C2H5)3 Sn(C2H6)2
Sn(C.HB)4. I II or Sn(G2H6)2.
Sn(C2H5)3. Sn(C2H6)2
Tin Tetraethyl. Tin Triethyl. Tin Diethyl.
The alkyl derivatives of tin were studied by Lowig, Cahours, Ladenburg, and
others. The reactions employed to cause the combination of tin with alkyls are
the same as were employed in the cases of arsenic, antimony, and other elements.
(i) The action of zinc alkyls on stannic chloride, whereby Sn(CH3)4 and
Sn(C2H6)4 are produced (B. 37, 320 ; C. 1904, I. 353)- (2) The action of alkyl
iodides on tin-sodium (tin alone or tin-zinc). When the alloy contains a great
deal of sodium, Sn(C2H6)2I2 is produced, but when comparatively little sodium
is present the chief product is Sn(C2H6)3I. Sodium abstracts iodine from
both of the primarily formed iodides with the formation of Sn2(C2H6)4 and
Sn2(C2H6)6. These can be separated by means of alcohol, in which the latter is
insoluble.
Tin Tetramethyl, Sn(CH3)<, b.p. 78°, and Tin Tetraethyl, Sn(C2H6)4, b.p.
181°, DM = i*i87; both are colourless, ethereal smelling liquids, insoluble in
water. By the action of the halogens the alkyls are successively eliminated ;
hydrochloric acid acts similarly :
Sn(C2H5)4+I2=Sn(C2H6)3I+C2H5I, etc.
Sn(C2H6)4+HCl=Sn(C2H5)3Cl+2C2H6, etc.
(For tin tetra-alkyls with different alkyl groups see C. 1904, I. 353.)
The alkyl groups are not so firmly united in the zinc alkyls as they are in the
alkyls of silicon.
Tin Triethyl Chloride, Sn(C2H6)3Cl, b.p. 208-210°, D = 1-428. Tin Triethyl
Iodide, Sn(C8H6)3,I, b.p. 231°, D22 = i'833. Alcohol and ether are solvents for
both. When either is acted on by silver oxide or potassium hydroxide, there
is produced :
Tin Triethyl Hydroxide, Sn(C2H5)3.OH, m.p. 66°, b.p. 272°, is sparingly
soluble in water, but dissolves readily in alcohol and ether. It reacts strongly
alkaline, and yields crystalline salts with the acids, e.g. Sn(C2H5)3.O.NO2; When
the hydroxide is heated for some time to almost boiling temperature, it breaks
down into water and Tin Triethyl Oxide, Sn(C2H ) ->O' an oily li(luid' which in
the presence of water at once regenerates the hydroxide.
Tin Triethyl, Sn2(C2H6)e, b.p. 265-270°, with slight decomposition (see above),
is a liquid, of mustard-like odour, insoluble in alcohol, but readily soluble in
ether. It combines with oxygen, forming tin triethyl oxide, snfC^H ) -^^
and with iodine yields tin triethyl iodide, Sn(C2H6)3I.
Tin Disthyl, Sn2(C2H6)4, or Sn(C2H6)2, is a thick oil, decomposing when
heated into Sn(CaH6)4 and tin. It combines with oxygen and the halogens.
Tin Diethyl Chloride, Sn(C2H6)2Cl2, m.p. 85°, b.p. 220°: iodide, Sn(C2H6)2I2,
m.p. 44-5°, b.p. 245°.
Ammonium hydroxide and the alkalis precipitate from aqueous solutions
of both the halogen compounds :
Tin Diethyl Oxide, Sn(C2H6H)2O, a white, insoluble powder. It is soluble in
excess of alkali, and forms crystalline salts with the acids, e.g. Sn(C8H6)2(ONO2)2.
Methyl Stannonic Acid, CH3SnOOH, is formed at ordinary temperatures
from iodomethane and an alcoholic solution of an alkaline stannous solution
similarly to the preparation of methyl sulphonic acid and methyl arsenic acid
(pp. 146, 177) from iodoethane and an alkaline solution of sulphurous and
arsenious acids :
K + KOH=CH,SnO,K+KI+HlO.
METALLO-ORGANIC COMPOUNDS 183
Methyl stannonic acid is a white amorphous powder, soluble in potassium
hydroxide solution, from which it is precipitated by CO2. Warming with alkalis
produces stannates and Dimethyl Stannic Oxide, which by distillation with alkalis
decomposes into stannates and Trimethyl Stannic Hydroxide :
2CH3Sn02K -r^ SnO8K2 + (CH8)2SnO.
3(CH3)2SnO 2K°> 2(CH3)3SnOH + K2S08.
Similarly, Ethyl Stannonic Acid yields Diethyl Stannic Oxide.
Methyl stannonic acid is transformed by the halogen acids into Methyl Stannic
Triiodide, CH3SnI3, m.p. 86°, Methyl Stannic Tribromide, CH3SnBr3, m.p. 53°,
and Methyl Stannic Trichloride, CH3SnCl3, m.p. 43°, which fume in the air like
tin tetrachloride. Thus, methyl stannonic acid behaves like cacodylic acid, as
an amphoteric electrolyte. Methyl stannic triodide can also be obtained from
stannous iodide and iodomethane at 160° ; from stannic iodide and magnesium
methyl-iodide together with Trimethyl Stannic Iodide, (CH3)3Sn, b.p. 170° (B. 36,
3027 ; 37, 4618) ; and by heating together tin tetramethyl and stannic iodide
(C. 1903, II. 106).
14. METALLO-ORGANIC COMPOUNDS
The metallo-organic compounds are those resulting from the union
of metals with univalent alkyls ; those with the bivalent alkylens,
CnH2w, have not yet been prepared. Inasmuch as we have no marked
line of difference between metals and non-metals, the metallo-organic
derivatives are connected, in the one direction, through the derivatives
of antimony and arsenic, with phosphorus and nitrogen bases ; and in
the other, through the selenium and tellurium compounds, with the
sulphur alkyls and ethers ; whereas the lead derivatives approach
those of tin, and the latter the silicon alkyls and the hydrocarbons.
Upon examining the metals as they arrange themselves in the periodic system
it is rather remarkable to find that it is only those which attach themselves
to the electronegative non-metals that are capable of yielding alkyl derivatives.
In the three large periods this power manifests and extends itself only as far as
the group of zinc (Zn, Cd, Hg). (Comp. Inorganic Chemistry.)
In a sense the metallic carbides, C2Na2, C2Ca, CaAl4 (pp. 67, 88) can also be
looked on as being metallo-organic compounds.
Those compounds in which the metals present their maximum
valence, e.g. :
II III IV IV
Hg(CH8)a A1(CH8)8 Sn(CH8)4 Pb(CH8)4
are volatile liquids, usually distilling without decomposition in vapour
form ; therefore, the determination of their vapour density is an accurate
means of establishing their molecular weight, and the valence of the
metals.
The behaviour of the metallo-organic radicals, derived from the molecules
by the loss of single alkyl groups, is especially noteworthy. The univalent
radicals, e.g. :
II III IV IV V
— Hg(CH8) — Tl(CH8)a — Sn(CH8)8 — Pb(CH8)8 — Sb(CH8)4,
show great resemblance to the alkali metals in all their derivatives. Like other
univalent radicals, they cannot be isolated. They yield hydroxides, e.g. :
Hg(C8H6).OH T1(CH,),.OH Sn(CH8)8.OH.
ig4 ORGANIC CHEMISTRY
which are perfectly comparable to KOH and NaOH. Some of the univalent
radicals, when set free from their compounds, become doubled :
As(CH3)8 Si(CH8), Sn(CH,), Pb(CH8),
As(CH8)2 Si(CH8)8 Sn(CH8)8 Pb(CH8)8.
By the loss of two alkyls from the saturated compounds, the divalent radicals
result :
III IV IV V
=Bi(CH8) «=Te(CH8)a =Sn(C2H6)2 =Sb(CH,)3.
In their compounds (oxides and salts) these resemble the divalent alkali
earth metals, or the metals of the zinc group. A few of them occur in the free
condition. As unsaturated molecules, however, they show strong inclination
to saturate two single affinities directly. Antimony triethyl, Sb(C2H6)s (see
p. 179), and apparently, also, tellurium diethyl, Te(C2H5)2, have the power of
uniting with acids to form salts, liberating hydrogen at the same time. This
would indicate a distinct metallic character.
Finally, the travilent radicals,Hke =As(CH3)2, can also figure as univalent,
as in the case of vinyl, C2H3. These may be compared to aluminium ; and
cacodylic acid, A9(CH8)2O.OH (p. 178), to aluminium metahydroxide, A1O.OH.
We conclude, therefore, that the electro-negative metals, by the successive
union of alcohol radicals, always acquire a more strongly basic, alkaline character.
This also finds expression with the non-metals (sulphur, phosphorus, arsenic,
etc.). (Comp. pp. 145, 173, 175.)
The first metallo-organic derivatives were prepared by Frankland.
Zinc alkyls are particularly important as alkylating bodies, but are
being replaced by magnesium alkyl halides, which are much more
convenient to work with.
Methods of Formation :
(1) Action of metals (Mg, Zn, Hg) on alkyl iodides.
(2) Action of alloys (Pb, Na) on alkyl iodides (see Bi-, Sb-, Sn-
compounds).
(3) Action of metals (K, Na, Be, Al) on metallo-organic bodies
(zinc alkyls, mercury alkyls).
(4) Action of metallic chlorides (PbCl2) on metallo-organic deriva-
tives (zinc alkyls or magnesium alkyl halides ; comp. BC13, SiCl4,
SnCl4, GeCl4 on zinc alkyls or magnesium alkyl halides).
A. ALKYL DERIVATIVES OF THE ALKALI METALS
When sodium or potassium is added to zinc methyl or ethyl, zinc separates
at the ordinary temperature, and from the solution which is thus produced,
crystalline compounds deposit on cooling. The liquid retains a great deal of
unaltered zinc alkyl, but it also appears to contain the sodium and potassium
compounds — at least it sometimes reacts quite differently from the zinc alkyls.
Thus, it absorbs carbon dioxide, forming salts of the fatty acids (Wanklyn, A. Ill,
234):
C2HBNa+COa=C2H6.COtNa.
Sodium Propionate.
These decomposable bodies cannot be separated in a pure condition.
B. ALKYL DERIVATIVES OF THE MAGNESIUM GROUP
Beryllium Ethyl, Be(C,H,),, b.p. 185-188°, formed by the 36. method, ignites
spontaneously. Beryllium Propyl, Be(C,H7)2, b.p. at 245°.
Magnesium Dimethyl, Mg(CHO, and Magnesium Diethyl, MgfC.H.),. result
ALKYL DERIVATIVES OF THE MAGNESIUM GROUP 185
from the action of Mg on the corresponding mercury compounds. They are
white, solid, substances, which inflame spontaneously even in a CO 2 atmosphere,
and are decomposed by heat, evolving hydrocarbons. They react with water
like the zinc alkyls (A. 276, 129).
Magnesium Alkyl Halides. — Whilst the magnesium alkyls are troublesome to
prepare and to manipulate, the preparation of the magnesium alkyl halides is
exceedingly easy and convenient, especially in solution. The metal is dissolved
in a solution of the alkyl halide in absolute ether, and the reagent is ready for
use:
C2H6Br+Mg=C8H6MgBr.
The general applicability of this reaction was first recognized by the French
chemist Grignard,* whose name is associated with the reaction and solution.
In a short time it was employed by a large number of investigators, and has
become an invaluable agent in organic synethesis.
The reaction proceeds most quickly in the case of alkyl iodides and bromides ;
whilst methyl and ethyl chlorides require assistance to react in the form of an
addition of iodine (B. 38, 2759) HgCl2 (C. 1907, I. 872) or a previously prepared
magnesium solution (B. 38, 1746 ; C. 1907, I. 455). Alkyl halides behave
similarly to the alkyl halides (B. 36, 2898). Sometimes the reaction pro-
ceeds abnormally, splitting off halogen acids, as in the case of isopropyl iodide,
and especially tertiary alkyl halides ; at low temperatures, however, the normal
reaction takes place (C. 1904, 1. 644 ; II. 183). It is of importance that the haloid
aryls, such as iodo- and bromo-benzene react analogously to the alkyl halides
(Vol. II.).
Distillation of the solvent ether leaves the magnesium alkyl halides behind
usually in the form of crystalline " etherates," RMgI.O(C2H8)2, RMgI.2O(C2H6)2,
which dissolve easily in ether, benzene, etc. If these double compounds are
decomposed in vacuo at raised temperatures, a greyish white mass remains ; it is
insoluble in ether, it becomes hot in contact with the air, and decomposes violently
in water. The ether apparently acts as a catalyzer in the Grignard solution ;
its action is weakened when other solvents, especially chloroform, carbon disul-
phide, etc., are employed (C. 1906, I. 130; II. 1718). Similarly to ether, the
tertiary amines, e.g. dimethylamine, also act catalytically, and these also form
double compounds with the magnesium alkyl halides, such as R'MgXNR, (B. 37,
3088; C. 1904, II. 836). The addition of a few drops of dimethyl aniline to a
benzene solution of iodoethane, for example, causes the production of pure
Ethyl Magnesium Iodide by the action of magnesium, in the form of a white
powder. This reacts analogously to the " etherates " and dissolves in ether,
with an evolution of heat, to form these bodies (B. 38, 4534 ; 39, 1674).
The ethereal solutions of the magnesium alkyl halides are very reactive and
exhibit similar reactions to those of the zinc alkyls, which, however, usually
run more smoothly (p. 186) :
(1) Water, alcohols, ammonia, primary, and secondary amines, bring about a
more or less violent decomposition, causing the generation of hydrocarbons :
C2H6MgI+ ROH=C2H6+ROMgI ; CaHgMgl+RNH^CjH.+RNHMgl. £
Acetylene and hydrocyanic acid behave similarly.
(2) Oxygen and sulphur are absorbed, and alcoholates and mercaptides
result : I
RMgX+0 >-ROMgX; RMgX-f-S=RSMgX.
(3) CO2f COS, CS2, SO2, are taken up, forming salts of carboxylic acids,
thiocarbonic acids, carbithionic acids, sulphinic acids, e.g. :
CaH5MgI+COa=C2H6COOMgI.
NO 2 forms salts of the /3-dialkyl hydroxylamines (p. 171) and NO those of the
j8-nitroso-alkyl hydroxylamines (p. 172).
Salts of the diazo-amino bodies result from hydrazoic esters.
(4) Aldehydes, ketones, carboxylic acid esters, anhydrides, chlorides and salts
yield primary, secondary, and, especially easily, tertiary alcohols (pp. 106, 108).
* " Sur les combinaisons organomagnesiennes mixtes et leurs applications
a des syntheses," Lyon, 1901. See also " Ueber die organischen Magnesium-
verbindungen und ihre Anwendung zu Synthesen," J. Schmidt, Stuttgart, 1905.
s
186 ORGANIC CHEMISTRY
Many of these tertiary alcohols give up water yielding defines, especially
in presence of an excess of RMgX ; e.g. diolefines (p. 90), etc.
Ethylene oxide and its homologues unite with the magnesium alkyl halides
to form alcohols (p. 106).
Formic acid derivatives, such as esters, orthoesters, imido ethers, dialkylamides,
isonitriles, under suitable conditions, yield aldehydes.
Carboxylic acid amides and nitriles frequently give rise to ketones.
The magnesium alkyl halides are added on to many a/?-olefine ketones,
carboxylic acid esters, and nitriles at the double bond, forming the corresponding
fl-alkyl paraffin compounds (C. 1907, I. 559, etc.).
With Schiff's base, RCH:NR', they form secondary amines, RR"CH.NHR'.
Often these bodies, ketones, and other substances are only reduced by the organo-
magnesium halides (B. 38, 2716 ; C. 1906, II, 312).
Iodine changes the magnesium alkyl chlorides and bromides to alkyl iodides
(P- T33}-
(6) Halogen or sulphuric acid compounds of many radicals have the haloid
or sulphuric acid residues replaced by alkyl, e.g. :
C,HnMgBr+BrCH2OCH3 ^C6HUCH2OCHS.
C6H11MgBr+S04(CH3)2 ^C5Hn.CH3.
By similar reactions for the preparation of isoamyl and isohexyl magnesium
bromides, diisoamyl and diisohexyl are formed as by-products (p. 76) (B. 36,
3084).
(7) On the formation of alkyl compounds of phosphorus, arsenic, antimony,
silicon, tin, lead, and thallium from organo-magnesium halides, and the chlorides
of these metals and metalloids, see the previous and following sections.
Calcium Ethyl Iodide is prepared similarly to the magnesium compound from
calcium and iodoethane in ether solution. It forms an " etherate," C3H6CaI.
O(CjH6)a which is a white amorphous powder, soluble with difficulty in ether.
It generates ethane when acted on by water (B. 38, 905).
C. ALKYL DERIVATIVES OF ZINC
Zinc methyl and zinc ethyl were discovered in 1849 by Frankland
(A. 71, 213 ; 85, 329 ; 99, 342). The zinc alkyls are exceedingly
reactive, and are, on this account, the most important class of the
metallic alkyls.
Methods of Formation. — (i) When zinc filings act on iodides
of the alcohol radicals in sunlight, iodides are formed, which are de-
composed by heat into zinc alkyls and zinc iodide :
CaH6I-fZn=IZnC2H5.
The action may be accelerated if the zinc turnings have been previously
corroded, or by the application of zinc-sodium or zinc-copper. In preparing
zinc ethyl, ethyl iodide is poured over zinc cuttings and a little pure zinc ethyl
is then added. The formation of IZn.C2H5 is then completed at the ordinary
temperature, and this body separates in large, transparent crystals. When it
is heated in a current of COa, it yields zinc ethyl (A. 152, 220 ; B. 26, R. 88 ;
C. 1900, II. 460). It is also formed by the solution of zinc in a boiling ether
solution of iodoethane (C. 1901, II. 24).
(2) The mercury alkyls are converted by zinc into zinc alkyls, with the
separation of mercury :
Hg(CaH6)a+Zn=Zn(C2H6)a+Hg.
Properties. — The zinc alkyls are colourless, disagreeable-smelling
liquids, fuming strongly in the air and igniting readily ; therefore,
MERCURY ALKYL DERIVATIVES 187
they can only be handled in an atmosphere of carbon dioxide. They
inflict painful wounds when brought into contact with the skin.
Zinc Methyl, Zn(CH3)a, b.p. 46° ; D10 = 1-386, and
Zinc Ethyl, Zn(C2H6)2, b.p. 118° ; D18=ri82, both solidify when cooled (B.
261, 59).
Zinc Propyl, Zn(CH2CH2CH3)2, b.p. 146°.
Zinc Isopropyl, Zn(C3H7)2, b.p. 136° (B. 26, R. 380).
Zinc Isobutyl, Zn(C4H9)2, b.p. 166° (A. 223, 168).
Zinc Isoamyl, Zn(C6Hn)2, b-P- 2IO° (A- 130» I22>-
Reactions. — The zinc alkyls are exceedingly reactive.
(1) Water decomposes them very energetically, forming hydrocarbons and
zinc hydroxide (see Methane, Ethane, pp. 71, 72).
(2) Oxygen is taken up by slow oxidation in the air, and compounds, e.g.
(CH3)2ZnO2, analogous to peroxides, are produced; they explode readily and
liberate iodine from potassium iodide (B. 23, 394).
(3) The alcohols convert the zinc alkyls into zinc alcoholates and hydro-
carbons, depending on the relative quantities of the reacting bodies, e.g. ethyl
zinc ethoxide, or zinc alcoholate maybe formed, together with ethane (C. 1901, II.
1200).
Zn(CA). — > Zn<°£H, _> Zn<OAH.
(4) The free halogens decompose both the zinc alkyls and those of other
metals very energetically :
Zn(CaH6)a+2Bra=2C2H6Br+ZnBr2.
(5) They react with chlorides of the heavy metals and the non-metals, whereby
alkyl derivatives of the latter are produced (p. 184).
(6) The zinc alkyls absorb sulphur dioxide and are converted into the zinc
salts of the sulphinic acids (p. 147).
(7) Nitric oxide and zinc diethyl produce the zinc salt of the so-called dinitro-
ethylic acid, CaH,.NaO2H.
The application of the zinc alkyls — zinc methyl and zinc ethyl — is particularly
important in nucleus-synthetic reactions :
(1) Hydrocarbons are formed when the alkyl iodides are exposed to high
temperatures (p. 75).
(2) When zinc alkyls (zinc and alkyl iodides) act on aldehydes, acid chlorides,
acid anhydrides (C. 1901, II. 188), ketones, formic esters, acetic esters, lactones,
and chlorinated ethers, derivatives of secondary, tertiary, and primary alcohols,
as well as of ketones, are produced. The alcohols (pp. 105, 106) and ketones
(p. 217) can easily be obtained from them.
The aikyl oxides and the alkylene oxides are, however, not affected by the zinc
alkyls (B. 17, 1968 ; C. 1901, II. 188), but, on the other hand, the heating together
of ethylene oxide and magnesium halides is a method of synthesis of the primary
alcohols (p. 1 8 6).
D. ALKYL DERIVATIVES OF CADMIUM
Cadmium Ethyl, Cd(CH3)2, b.p. 104°, is prepared in very small quantities by
heating the product of reaction of cadmium and iodomethane. It solidifies in a
freezing mixture. Its properties closely resemble those of zinc methyl.
E. ALKYL DERIVATIVES OF MERCURY
The dialkyl compounds are formed —
(i) by the interaction of sodium amalgam and alkyl iodides, with the addition
of acetic ester (Frankland, A. 130, 105, 109). The role of the acetic ester in this
reaction has not yet been explained :
2C1HiI+Hg.Naa=»(C1Hi)1Hg+2NaI.
i88 ORGANIC CHEMISTRY
(2) by the action ot potassium cyanide on mercury alkyl iodides ;
(3) by the action of zinc alkyls on mercury alkyl iodides :
2C2H6HgI-fZn(C1H6)4=2(C8H6)1Hg+ZnIs.
(4) by the action of zinc alkyls on mercuric chloride :
HgCl2+Zn(C2H,)2=(C2H6)2Hg+ZnCl,:
Properties. — These compounds are colourless, heavy liquids, possessing a faint,
peculiar odour. Their vapours are extremely poisonous. Water and air occasion
no change in them, but when heated they ignite easily.
Mercury Methyl, Hg(CH,)s, b.p. 95°, 0=3-069. Mercury Ethyl, Hg(CaH6)2,
b.p. 159°, D=2'44, and at 200° breaks down into Hg and butane, CaHB.C2H6. It
yields ethane (p. 73) when treated with concentrated sulphuric acid.
Mercury sec.-Butyl, Hg[CH(CH8)(C2H5)]a, b.p.15 91-93°. is prepared by elec-
trolytic reduction of methyl ethyl ketone in sulphuric acid solution at 50° with a
mercury cathode (B. 39, 3626).
2C4H80+Hg+6H=Hg(C4H9)2+2H20.
The mono-alkyl derivatives arise (i) by the action of mercury on alkyl iodides
in sunlight; C2H6I+Hg=C2H8.Hg.I ; (2) from the dialkyl mercury derivatives
— (a) by the action of halogens ; (b) by the action of the halogen acids ; (c) by
the action of mercuric chloride.
Mercury Methyl Iodide, CH8HgI, m.p. 143°, forms shining needles, and is
insoluble in water. Silver nitrate changes it to methyl mercury nitrate,
CH,Hg.ONOt. Mercury Ethyl Iodide, C2H6HgI, is decomposed, by sunlight,
into mercuric iodide and C<H10. Mercury Allyl Iodide, C8H6HgI, m.p. 135°,
is converted by HI into propylene and mercuric iodide, Hgla. Moist silver
oxide changes the haloid derivatives to hydroxyl compounds :
C2HfHgCl+AgOH=C1H6.Hg.OH+AgCl.
Ethyl Mercuric Hydroxide, C2H,HgOH, is a thick liquid, soluble in water and
in alcohol. It reacts strongly alkaline, and forms salts with acids.
Mercury compounds, derivable from glycol, result from the action of ethylene
on mercuric salts (B. 34, 2910).
F. ALKYL DERIVATIVES OF THE METALS OF THE ALUMINIUM GROUP
The aluminium alkyl derivatives are comparable to those of boron (p. 180).
They are produced by the action of the mercury alkyls upon aluminium filings.
Aluminium Trimethyl, A1(CH8)3, b.p. 130°. Aluminium Triethyl, A1(C2H6)3,
b.p. 194°. Both are colourless liquids and are spontaneously inflammable.
Water decomposes them with great violence, forming methane (or ethane) and
aluminium hydroxide. Their vapour densities indicate a mono- rather than a
di- molecular constitution (see B. 22, 551 ; Z. phys. Ch. 3, 164).
The derivatives of trivalent gallium and indium have not been prepared.
Thallium Dimethyl Chloride, Bromide and Iodide (CH8) aT!X, as weU as Thallium
Diethyl Chloride, Bromide, and Iodide, and Thallium Dipropyl Chloride, Bromide, and
Iodide, are prepared by the interaction of thallium chloride, T1C1S, and magnesium
alkyl halides in ether solution (p. 185). They are crystalline bodies, dissolving
in water with great difficulty, and decomposing on being subjected to heat.
They can be recrystallized from an alkaline aqueous solution without decomposi-
tion ; moist silver oxide produces strongly alkaline, easily soluble hydroxides, e.g.
Thallium Diethyl Hydroxide, Tl(CaH6) 2OH, which absorb CO, from the atmosphere
and precipitate hydroxides from solutions of the metals, thus resembling thallous
hydroxide T1OH (B. 37, 2051).
G. ALKYL DERIVATIVES OF LEAD
These are very similar to the derivatives of tin (p. 182), but those
containing two alkyl groups combined with one atom of lead do not
ALDEHYDES AND KETONES 189
exist. In these the lead, as in most of its inorganic derivatives, would be
bivalent. Lead alkyls are produced (i) by acting on lead chloride
with zinc ethyl or magnesium ethyl iodide (B. 37, 1127) : Pb(C2H5)4 ;
(2) by the interaction of alkyl iodides and lead-sodium : Pb2(C2H6)6.
Lead Tetramethide, Pb(CH,)4, b.p. no0. Lead Tetraethide, Pb(C,HB)4, and
Lead Triethide, Pb2(CaH5)8, are oily liquids which cannot be distilled without
decomposition. Lead Triethyl Chloride, Pb(C2H6)8Cl, and Lead Triethyl Iodide,
Pb(CaH6),I, are prepared from lead tetraethyl and triethyl by hydrochloric acid
or iodine. The iodide is transformed by moist silver oxide into a thick strongly
alkaline liquid, dissolving with difficulty in water and forming salts with acids.
Lead Trietbyl Sulphate, [Pb(C1H6),],SO4, is slightly soluble in water.
2. ALDEHYDES AND 3. KETONES
When the derivatives of the methane hydrocarbons containing
oxygen were discussed, attention was directed to the intimate genetic
relations existing on the one hand between the primary alcohols,
the aldehydes and mono-carboxylic acids, and on the other between
the secondary alcohols and the ketones (p. 100).
Aldehydes and ketones contain the carbonyl group CO, which in
the latter unites with two alkyl groups, but in the former is combined
with only one alkyl and one hydrogen atom :
Aldehyde. Dimethyl Ketone.
This expresses the similarity and the difference in character of
aldehydes and ketones.
Aldehydes and ketones may be considered as the oxides of bivalent
radicals, or as the anhydrides of dihydroxy alcohols, or glycols, in which
both hydroxyl groups are attached to the same terminal or inter-
mediate carbon atom. Whenever the formation of dihydroxyl deriva-
tives of the type >C<Q~^ might be expected, then, except in very
rare instances, water separates, an anhydride is produced, and double
union between carbon and oxygen follows, with the production of the
carbonyl group >C=O. Ethers, however, of dihydroxy alcohols, of
the ortho-aldehydes and ortho-ketones, can exist, e.g. :
CHt.CH(O.CaH6), and CHs.C(O.C,H6)t,CH8.
The three classes of alcohols (p. 102) are differentiated from each
other by the words primary, secondary, and tertiary ; the oxidation
products, however, of the first two have received special names — alde-
hyde and ketone — although they are no more different from each other
than their respective parent alcohols. A practical and excellent
nomenclature would have been primary and secondary aldehydes, for
then the name aldehyde, derived by Liebig from alcohol dehydrogenatus
(p. 199), would have applied to both. The complete difference in the
designation of aldehyde and ketone leads to the separate description
of the formation and reactions of the two classes of bodies (Anschutz).
The following principal methods of formation are common to
aldehydes and ketones :
igo ORGANIC CHEMISTRY
(i) Oxidation of the alcohols, whereby the primary alcohols change
to aldehydes and the secondary to ketones (p. 103).
In this oxidation an oxygen atom enters the molecule between a hydrogen
atom and the carbon atom to which the hydroxyl group is joined. In the moment
of formation the expected hydroxy alcohol splits off water, and its anhydride
results, — an aldehyde or ketone :
CH3CH2OH - % (CH3.CH<gg) - >. CH8.C<°+H2O.
Primary Alcohol.
Sec.-Propyl Alcohol. Cannot exist. Acetone.
By further oxidation the aldehydes become changed into acids — the hydrides
of the acid radicals, — whilst the ketones are decomposed.
Conversely, aldehydes and ketones are reconverted into primary
and secondary alcohols by an addition of hydrogen :
CH8.CHO+H2=CH8.CH2.OH.
Aldehyde. Ethyl Alcohol.
CH;>CO+H>=CH;>CH-OH-
Aceto e. Isopropyl Alcohol.
Because the aldehydes and ketones manifest an additive power
with reference to hydrogen, they may be compared with compounds
containing doubly linked carbon atoms, which also, by a dissolution of
their double union, can add hydrogen. Compounds of this class
having in their molecules carbon atoms which are doubly or trebly
united, are in the more restricted sense called " unsaturated carbon
derivatives " (p. 69). This idea may be extended, and all carbon
derivatives having atoms of other elements in double or treble union
with carbon, may be considered as " unsaturated." From this stand-
point the aldehydes and ketones are unsaturated bodies (p. 23), and
in fact most of the reactions of these two classes are due to the additive
power of the unsaturated carbonyl group.
(2) The dry distillation of a mixture of the calcium, or better,
barium salts of two monobasic fatty acids produces aldehydes or
ketones according as one of the acids be formic acid or not.
H.COOv- , CH8.CO(X ~ CH..COH , oPorn
H.COO>Ca+CHl.COO>Ca = CHl.COH+2CaCO»'
Calcium Formate. Calcium Acetate. Acetaldehyde.
It is the hydrogen of the formate which reduces the acid, whereby
an aldehyde results.
In all other instances ketones result, and they are either simple,
with two similar alkyl groups, or mixed, with two dissimilar alkyls :
CH8.CO(X ~ CHsXrri , r rn
CH8.COO>Ca=CHl>CO+CaCO»-
Acetone.
CH8.CO(X ~ , C2HBCO(X ~ CaH,^,- . r rr.
CH8.COO>Ca+C2H'cOO>Ca=2CH8>CO+2CaCO»-
Calcium Propionate. Ethyl Methyl Ketone.
On extending this reaction to the calcium salts of adipic, pimelic and suberic
acids, cyclo-paraffin ketones are produced.
ALDEHYDES OF THE SATURATED SERIES 191
2A. ALDEHYDES OF THE SATURATED SERIES, PARAFFIN
ALDEHYDES, CnH2n+1.CHO
The aldehydes exhibit in their properties a gradation in behaviour
similar to that of the alcohols. The lower members are volatile
liquids, soluble in water, and have a peculiar odour, but the higher
are solids, insoluble in water, and cannot be distilled without decom-
position. In general they are more volatile and dissolve with more
difficulty in water than the alcohols. Chemically the aldehydes are
neutral substances (B. 39, 344).
The reactivity of the aldehydes places them amongst the most
important substances for purposes of synthesis, and it is for this reason
that the large number of methods for their preparation is being con-
siderably increased, especially during the latter years (Bull. Soc. Chim.
[3] 31, 1306).
Formation. — (i) By the oxidation of primary alcohols, whereby
the — CH2.OH group becomes changed to — CHO (p. 190).
The above oxidation may be effected by atmospheric oxygen in presence of
spongy platinum, and by the action of potassium dichromate or MnO2 and dilute
sulphuric acid (B. 5, 699). Chlorine acts similarly in that it first oxidizes the
primary alcohols, but then substitutes the alkyl groups of the aldehydes which
have been formed (p. 196).
Oxidation of alcohol leads to a good yield of aldehyde with the lower mem-
bers of the series only, where the product is sufficiently volatile to escape
quickly from the region of reaction ; otherwise the aldehyde is further oxidized
to a carboxylic acid, which in turn unites with some of the unchanged alcohol
to form an ester.
(2) A direct decomposition of a primary alcohol into H8 and an aldehyde is
brought about by passing alcohol vapours through a red hot tube, or, better, over
finely divided copper at 200-350° (B. 36, 1990; C. 1905, I. 1002).
(3) Primary amines are oxidized to aldehydes by the air in presence of
powdered copper (comp. p. 163).
The following methods of preparation depend on the reduction of carboxylic
acids : —
(4) By heating the calcium salts of fatty acids with calcium
formate. This operation, when working with aldehydes which vola-
tilize with difficulty, should be carried out under diminished pressure
(p. 49) (B. 13, 1413).
(5) By the action of nascent hydrogen (produced by sodium
amalgam, or, better, by sodium on the moist ethereal solution
B. 29, R. 662) of the chlorides of the acid radicals or their oxides,
the acid anhydrides :
CH3.COC1+2H=CH8.COH+HG1.
Acetyl Chloride. Acetaldehyde.
CH^co
Acetic Anhydride. Acetaldehyde.
Hydra/ones of the aldehydes are obtained by reduction of imido-ethers of
carboxylic acids by sodium amalgam in acid solution in the presence of hydra-
zines (B. 38, 1362).
In accordance with methods (3) and (4) the aldehydes may be
viewed as hydrides of the acid radicals.
I92 ORGANIC CHEMISTRY
(6) Of practical importance is the preparation of aldehydes by the
splitting up, or hydrolysis of their compounds :
(a) from aldehyde-ammonia and aldehyde-bisulphite compounds (see below) ;
from oximes and hydrazones (p. 196) ;
(b) from aldehyde chlorides (p. 196) by heating them with water and lead
oxide :
CH8CHC12 >- CH3CH(OH)a > CH3CHO ;
(c) from ethers and esters of aldehyde hydrate, the acetals and alkylidene
diacetates, by means of dilute alkalis or acids :
/OR /OH
CH,CH< > CH,CH< > CH3CHO.
\DR XOH
In the course of these reactions i,i-glycols, dihydroxyl compounds, should
be formed ; if they are, they instantly give up water and pass into aldehydes
(p. 190). The following methods of formation from i,2-glycols take their places
systematically here.
(7) From ethylene glycol or its ethers, or from ethylene oxide by
the withdrawal of water or alcohol and internal rearrangement :
(a) Ethylene glycol, CHaOH.CH2OH, yields acetaldehyde when heated with
zinc chloride, PaO,,"sulphuric acid, etc., Diethylene ether, O(CH2.CH2)aO, may be
assumed to be an intermediate product (C. 1907, I. 15).
(b) Primary-secondary ethylene glycols yield a mixture of aldehydes and
ketones when similarly treated.
(c) Primary-tertiary ethylene glycols yield aldehydes when heated with
anhydrous formic and oxalic acid; the ethers, R2C(dH).CH2OR, react parti-
cularly easily (B. 39, 2288 ; A. Ch. phys. [8] 9, 484) :
RaC(OH).CH2OCaH6=R2CH.CHO+C2H6OH.
(d) Ethylene oxide and its homologues, especially the primary-tertiary com-
pounds, undergo internal rearrangement when heated with zinc chloride, a
contact substance, or even alone, to form principally aldehydes (B. 36, 2016 ;
C. 1905, II. 237) :
CH,\ CH, CH,(C2H6)(X (CHa)(C2H6)CH
I >0 V I ; | \Q > |
CH/ CHO HaC/ HCO.
i,3-glycols also yield some aldehyde, together with trimethylene oxides.
(8) The sodium salts of the primary nitre-paraffins yield aldehydes and N2O
when treated with acids. Nitro-a/3- defines of the formula RCH=CHNO2on
reduction yield oximes of the aldehydes (C. 1903, II, 553) :
(CH,)aC:CHNOa >• (CH,)2CH.CH:NOH — >• (CH8)2CH.CHO.
Compare the cleavage of secondary chloramines, R2NC1, and nitr amines,
RaN.NO2 (pp. 167, 169), into aldehydes, also their formation from afi-olefine alkyl
ethers, RCH : CHOCaH, (p. 129), by hydrolysis.
Since the nitro-olefines are formed from aldehydes by means of nitromethane
(p. 151), these changes can be looked on as a step-by-step synthesis up the aldehyde
series.
Such a building up of the aldehydes can be carried out by the
organo-magnesium synthesis (p. 186).
(9) Alkyl magnesium halides with an excess of formic acid ester
or formic acid dialkyl amides yield aldehydes ; with orthoformic acid
ester, acetals (p. 205) ; with isonitriles and with formimido-ethers,
aldehyde imides (p. 211) (A. 347, 348; B. 37, 186, 875; C. 1904, I.
1077; 1905, 1.219):
RMgX+HCO2C2H5 > RCHO + XMgOC2H8.
RMgX+HCON(C2H5)2 > RCHO+XMgN(C2H6)2.
RMgX+HC(OC2H6)8 > RCH(OC2H6)a+XMgOC2H8.
RMgX+C,H6N:CHOC8H6
ALDEHYDES OF THE SATURATED SERIES 193
Also, formates are partially converted into aldehydes by means of alkyl
magnesium halides (C. 1901, II. 765).
(10) aj8- olefine aldehydes, or better their acetals, yield paraffin aldehydes on
reduction (B. 31, 1900). Since the olefine aldehydes result from condensation
of the lower paraffin aldehydes (p. 196) this also constitutes a method of passing
synthetically up the aldehyde series.
Conversely, the following degradation reactions may be employed in the
production of aldehydes.
(u) a-Hydroxycarboxylic acids, RCH(OH)COOH, which are easily obtained
from the fatty acids, yield aldehydes and some formic acid, or CO-j-H,O, by
treatment with sulphuric acid. A better method is to heat the hydroxy- acids,
converting them by loss of water into lactides, and to distil these, so that they lose
CO and pass into aldehydes (C. 1904, I. 1065) :
CH,CH(OH)COOH=CH,CHO + HCOOH.
Lactic Acid. Acetaldehyde Formic Acid.
2C4H9CH(OH)COOH >C^U9CU<^Q^>CHC^I9 > 2C4H9CHO+2CO.
a-Hydroxycapronic Acid. Valer aldehyde.
(12) Connected with this reaction is the formation of aldehyde .by heating
ethylene oxide carboxylic acid, or glycidic acids, whereby ethylene oxides are
formed which become rearranged (Method of formation, yd, p. 192) into aldehyde
(C. 1906, II. 1297).
(CH8)2C (CH8)aCH
|>0 > | +C0t.
HOCO.CH CHO
Similarly, a-ketonic acids when heated with dilute sulphuric acid, yield aldehyde
+C02.
CH8COCOOH > CH3CHO+CCV
(13) defines absorb ozone to form ozonides (p. 84), which may be decomposed
by water, giving the results indicated as follows (A. 343, 311) :^—
CH8[CH,]7CH:CH[CHa]7COOH > CH8[CH2]7CHO+OCH[CHa]7COOH.
Oleic Acid. Nonyl Aldehyde. Azelaic Aldehydic Acid.
This reaction is particularly important for the determination of constitution
and for the preparation of dialdehydes and ketone-aldehydes.
Quite frequently aldehydes occur among the decomposition pro-
ducts of complex carbon compounds, such as albumins, as the result
of their oxidation with manganese dioxide or dichromate and dilute
sulphuric acid.
Nomenclature and Isomerism. — Empirically, the aldehydes are dis-
tinguished from the alcohols by possessing two atoms less of hydrogen
— hence their name, suggested by Liebig (from Alkohol dehydrogenatus),
e.g. ethyl aldehyde, propyl aldehyde, etc., etc. On account of their
intimate relationship to the acids, their names are also derived from
the latter, like acetaldehyde, propionaldehyde, etc.
In the " Geneva nomenclature " the names of the aldehydes are formed from
the corresponding saturated hydrocarbons by the addition of the suffix al ; thus
ethyl- or acetaldehyde would be termed [ethanal] (p. 42).
As there is an aldehyde corresponding with every primary alcohol,
the number of isomeric aldehydes of definite carbon content equals
the number of possible primary alcohols having the same carbon
content (p. 101). The aldehydes are isomeric with the ketones, the
VOL. I. O
IQ4 ORGANIC CHEMISTRY
unsaturated olefine alcohols, and the anhydrides of the ethylene-
glycol series, containing an equal number of carbon atoms, e.g. :
CH..CH..CHO isomeric with CH3.CO.CH, CH2=CHCH2OH CHa<£g|>O.
Propionaldehyde. Acetone. Allyl Alcohol. Trimethylene Oxide.
Reactions of the Aldehydes: A. Reactions in which the carbon
nucleus of the aldehydes remains the same.
(i) Aldehydes, by oxidation, yield monocarboxylic acids with a
like carbon content. They are powerful reducing agents :
CH8C<^+0=CH3— C<QH.
Their ready oxidation gives rise to important reactions serving for their
detection and recognition. On adding an aqueous aldehyde solution to a weak
ammoniacal silver nitrate solution, silver separates on the sides of the vessel as
a brilliant mirror ; alkaline copper solutions are also reduced. They impart
an intense violet colour to a fuchsin solution previously decolorized by sul-
phurous acid. Further, aldehydes produce a violet-red coloration in a solution
of diazobenzene sulphonic acid in sodium hydroxide, in the presence of sodium
amalgam. On the exceptions to, and the limitation of, these reactions, see
B. 14, 675, 791, 1848 ; 15, 1635, 1828 ; 16, 657 ; 17, R. 385.
When oxygen or air is conducted through the hot solution of an aldehyde
(such as paraldehyde) in potassium hydroxide, a display of light is observed in the
dark ; many aldehyde derivatives, and even dextrose, behave similarly (B. 10,
321). Aldehydes absorb oxygen from the air. The oxygen in this solution, like
ozone, liberates iodine from a potassium iodide solution (B. 29, 1454).
Aldehydes form addition-products with ozone, which, with water, yield
aldehydes at low temperatures and acids at high (A. 343, 326).
Salts of nitrohydroxylaminic acid, e.g. HON:NOONa, which is formed from
hydroxylamine, alkyl nitrates, and sodium alcoholate, form hydroxamic acids
with aldehydes, ^^^. • which are easily detected by the red colour given
with ferric chloride (a sensitive reaction for aldehydes'. C. 1904, I. 1204).
2. Acetaldehyde is resinified by alkalis ; other aldehydes are
transformed by alcoholic alkali solutions into acids and alcohols —
particularly the aromatic aldehydes (see Benzaldehyde, Vol. II.),
where the aldol condensation is impossible (p. 196). Among the
aliphatic series, a similar reaction is brought about by barium
hydroxide solution in the case of isobutyl aldehyde (C. 1901, II.
762). A carboxylic ester of an alcohol may be assumed to be
formed as an intermediate product, which is decomposed by the
barium hydroxide :
^-H
2(CH,)aCHCHO - > (CH8),CHO-H
\O— CO.CH(CH,)t
I
(C
(CH3) 2CHCHaOH +COaH.CH(CH8) f .
Esters do actually result, even from the simplest aldehydes, with
anhydrous condensing agents, such as the aluminium alkylates ; for
instance, A1(OCH3)3 with formaldehyde, or trioxymethylenes, give
methyl formate, with acetaldehyde ethyl acetate, with propionaldehyde
propyl propionate, with chloral trichlorethyl trichloracetate, etc.
(C. 1906, II. 1552).
The ease with which the double bond between the carbon-oxygen
ALDEHYDES OF THE SATURATED SERIES 195
atoms is broken is the cause of a large number of addition reactions,
which are in part followed by a loss of water.
(3) Aldehydes, by the addition of nascent hydrogen, or of mole-
cular hydrogen in presence of reduced nickel (C. 1903, II. 708), are
converted into the primary alcohols, from which they are obtained
by oxidation :
CH8.CHO+2H==CH8.CH2OH.
(4) Behaviour of the aldehydes towards water and alcohols, (a) Ordi-
narily, aldehydes do not combine with water (comp. p. 199 ;
CH2(OH)2). The polyhalide aldehydes, e.g. chloral, bromal, butyl chloral
(pp. 202, 203), however, have this power, and yield feeble and readily
decomposable hydrates, representatives of dihydroxy alcohols or glycols,
both hydroxyl groups of which are attached to the same carbon atom :
CC13CH<°^ CBr3CH<°** CH8.CHC1.CC12CH<°**.
Chloral Hydrate. Bromal Hydrate. Butyl Chloral Hydrate.
(b) It is also only the polyhalide aldehydes, e.g. chloral, which unite with
alcohols, forming aldehyde-alcoholates :
CC13CH<OH2H5 Chloral Alcoholate.
(c) The ordinary aldehydes yield acetals with the alcohols at 100° (p. 205) :
CHS.CHO +2C,H,.OH =CH3.CH<'2» + H2O.
Acetal or Ethylidene Diethyl Ether.
(5) Behaviour of the aldehydes with hydrogen sulphide and mercaptans : (a) hydro-
gen sulphide and hydrochloric acid convert the aldehydes into trithioaldehydes :
(b) with mercaptans the aldehydes enter into an acetal synthesis under the
influence of hydrochloric acid (p. 209).
(6) Aldehydes and acid anhydrides unite to form esters of the hydroxy-
alcohols or glycols, which are not stable in an isolated condition. Indeed, the
aldehydes may be regarded as their anhydrides (p. 189) :
Ethylidene Diacetate.
(7) Aldehydes unite in a similar manner with alkali bisulphites,
forming crystalline compounds :
CH3.CHO+NaHSO8=CH,.CH<°^Na.
(Constitution, see p. 207.) The aldehydes may be liberated from
these salts by distillation with dilute sulphuric acid or aqueous sodium
hydroxide. This procedure permits of the separation and purification
of aldehydes from other substances.
(8) Behaviour of aldehydes with ammonia, primary alkylamines,
hydroxylamine, and phenylhydrazine (C6H5.NH.NH2). (a) They unite
directly with ammonia to form crystalline compounds, called alde-
hyde-ammonias. These are readily soluble in water but not in ether,
hence ammonia gas will precipitate them in crystalline form from the
ethereal solution of the aldehydes. They are rather unstable, and
dilute acids again resolve them into their components. Pyridine
bases are produced when the aldehyde-ammonias are heated.
196 ORGANIC CHEMISTRY
(b) Aldehydes and primary amines combine, with loss of water,
to form aldehyde-imides (p. 158).
(c) The aldehydes unite with hydroxylamine to form aldoximes
with accompanying liberation of water (V. Meyer, B. 15, 2778).
It is evident that at first, in these cases, there is formed an unstable
intermediate product (compare chloral hydroxylamine, p. 212) corre-
sponding with aldehyde-ammonia :
NH2OH / /NHOH\ —HaO
2 > (CH8.C^OH j — > CH3.CH:NOH.
(d) The aldehydes behave similarly with phenylhydrazine ; water
separates and hydrazones (E. Fischer) result :
CHs.CHO+HaN.NHC,H8=CH8.CH:NNHG.H6+HaO.
These substances serve well for the detection and characteri-
zation of the aldehydes. The aldoximes and hydrazones, when boiled
with acids, absorb water and revert to their parent substances. They
yield primary amines when reduced (p. 158).
(e) Hydrazine, semicarbazide (q.v.), £-amido-dimethylaniline (B. 17, 2939),
amidophenols, and other aromatic bases (Schiff, B. 25, 2020) react with aldehydes,
similarly to phenylhydrazine and its substitution products.
(9) Compounds are formed by the action of phosphorus trichloride on
aldehydes, which are converted by water into hydroxalkyl phospho-acids, e.g.
CH8.CH(OH)PO(OH)a (B. 18, R. in).
(10) Phosphorus pentachloride and phosphorus trichloro-dibromide
cause the replacement of the aldehyde oxygen by chlorine or bromine
and yield dichlorides and dibromides, in which the two halogen atoms
are linked to a terminal carbon atom (p. 94) :
CH8CHO+PC1S=CH8CHC18+POC1,.
(11) The hydrogen atoms of the alkyl groups of the aldehydes may
be replaced by chlorine and bromine, as well as by iodine and iodic
acid.
(12) The lower members of the homologous series of the aldehydes
polymerize very readily. The polymerization of the aldehydes and
thioaldehydes depends on the union of several aldehyde radicals,
CH3.CH=, through the oxygen or sulphur atoms (A. 203, 44). This
phenomenon will be fully treated under formaldehyde and acetalde-
hyde (p. 197).
B. Nucleus synthetic Reactions of the Aldehydes.
(i) Aldol Condensations. — Two or more aldehyde molecules may
unite together, under proper conditions, by means of their carbon
linkings. Thus, aldehyde alcohols are formed from two aldehyde
molecules, e.g. acetaldehyde yields Aldol (Wiirtz) or fl-hydroxy-
butyraldehyde, CH3.CHOH.CH2.CHO (q.v.); from three aldehyde
molecules fatty acid esters of the glycols are formed, as for example,
isobutyl aldehyde which gives rise to monoisobutyryl octyl glycol,
(CH3)2.CH.CH(OH).C(CH3)2.CH2OCO.CH(CH3)2 (C. 1898, II. 416).
ALDEHYDES OF THE SATURATED SERIES 197
Similarly, aldehyde or chloral and acetone (p. 221), aldehyde and malonic
or cyanacetic ester and others, unite with one another. But almost invariably
the resulting hydroxy-derivatives split off water and pass into unsaturated
bodies : aldol into crotonaldehyde, CH3CH = CH.CHO, for example. On the other
hand, if the aldehyde group is joined to a secondary alcohol radical, the aldol
condensation occurs as before, but no olefine aldehyde can be obtained from the
aldol formed. If the aldehyde group is united to a tertiary alcohol radical, no
aldol condensation takes place (C. 1901, I. 1266).
These are nucleus-syntheses and are often termed condensation reactions.
The reagents suitable for the production of such reactions are mineral acids,
zinc chloride, alkali hydroxides, solutions of sodium acetate or potassium cyanide,
small quantities of amines or their salts, etc. Condensation reactions, in which
an aliphatic aldehyde plays the role of one of the component or parent substances,
will be frequently encountered. A reaction discovered by Perkin, Sr., when
working with aromatic aldehydes, has been employed quite frequently to unite
aldehydes and acetic acid, as well as mono-alkyl acetic acids, in such a manner
that the products are unsaturated monocarboxylic acids (see nonylenic acid}.
The aldehydes unite in like manner with succinic acid, forming y-lactone carboxylic
acids — the paraconic acids (q.v.).
(2) Aldehydes can also unite with zinc or magnesium alkyls,
whereby the double union between carbon and oxygen is broken.
The action of water on the addition product produces a secondary
alcohol (p. 106). Olefine alcohols result by the use of allyl iodide and
zinc or magnesium (p. 124).
(30) Aldehydes also combine with hydrogen cyanide, yielding
hydroxy-cyanides or cyanhydrins — the nitrites of a-hydroxy-acids (q.v.),
which will be discussed after the a-hydroxy-acids themselves, and
which can be obtained from them by means of hydrochloric acid :
C
[
HC1 /C°»H
CH8.CHO+HNC=CH3.CH< HC1 > CH,.CH<
Lactic Acid. XOH
(b) Aldehydes and ammonium cyanide react together, when water separates,
and the nitriles of a-amino-acids , e.g. CH8.CH<(-,-N a, result. When treated with
hydrochloric acid they yield amino-acids (q.v.). The same amino-nitriles are
produced by the action of CNH on the aldehyde-ammonias, and from the
hydroxy-cyanides and ammonia. Cyanides of a-anilino and a-phenylhydrazino-
acids are formed by the addition of hydrocyanic acid to the aliphatic aldehyde-
anilines and aldehyde phenylhydrazones and aldoximes (B» 25, 2020).
(4) Diazomethane (p. 213) and aldehydes produce alkyl-methyl ketones, with
evolution of nitrogen, and probably with the formation of an intermediary
addition product (B. 40, 479, 847) :
C6H1SCH CH2 C6Hi3CCH8
II + / \ ' II
O N=N O
Aromatic diazo-compounds react similarly with many aldoximes, forming
fatty-aromatic ketoximes (B. 40, 737).
Formic Aldehyde, Methyl Aldehyde [Methanal], H.C<H» m-P-
about —92° (6.34,635), b.p. about —21°, D~80=o'9i72, D_20=0'8i53,
was discovered by A. W. Hofmann, and was until recently only known
in aqueous solution and in vapour form. It may, as was shown by
Kekule, be condensed, by lowering the temperature to a colourless liquid.
Liquid formaldehyde changes slowly at —20°, rapidly at the ordinary
temperature, with a crackling noise, into trioxymelhylene, (CH20)3 (B. 25,
I98 ORGANIC CHEMISTRY
2435). This polymeric modification was known before the simple
formaldehyde, into which it is changed by heat. Formaldehyde
possesses a sharp, penetrating odour, and destroys bacteria of the most
varied types ; it is, therefore, applied (under the name of formalin)
either in solution or as a gas, for disinfecting purposes. Many of its
compounds with organic bodies are suitable for this purpose, as they
regenerate formaldehyde more or less easily (B. 27, R. 757, 803 ; 28,
R. 938 ; 29, R. 178, 288, 426 ; C. 1900, 1. 263, 791, etc.).
Methods of Formation.— (i) It is produced when the vapours of
methyl alcohol, mixed with air, are conducted over an ignited platinum
spiral or ignited copper gauze (J. pr. Ch. 33, 321 ; B. 19, 2133 ; 20,
144 ; A. 243, 335) : lamps have been constructed for this purpose
(B. 28, 261).
(2) When chlorine and bromine act on methyl alcohol, formaldehyde is pro-
duced (B. 26, 268), and is converted by them in sunlight into halogen acids and
carbon dioxide (B. 29, R. 88).
(3) If a mixture of methane (obtained from the distillation of
wood, p. 71) and air is passed over heated copper gauze, formal-
dehyde is formed (C. 1905, I. 1132).
(4) It also arises in small quantity in the distillation of calcium formate.
(5) Further, by the digestion of methylal, CH2(OCHS)2 (p. 205), with sulphuric
acid (B. 19, 1841). (6) From the nitrile of acetyl glycollic acid, CH8.COOCH2CN,
by the action of an ammoniacal silver solution (C. 1900, II. 312).
Technically, formaldehyde is prepared from methyl alcohol or methane,
and its 40 per cent, aqueous solution and many derivatives are known to com-
merce ; the year's production of formaldehyde reaches a million kg. (Z. angew.
Ch. 19, 1412]!. The strength of the solution can be estimated by converting the
formaldehyde into hexamethylene tetramine (CH2)6N4 (B. 16, 1333 ; 22, 1565,
1929 ; 26, R. 415), or into dimethylene ^-dihydrazinophenyl (B. 32, 1961).
The following methods are, however, more exact. The formaldehyde is trans-
formed by hydrogen peroxide in alkaline solution of known strength into sodium
formate and hydrogen, under the influence of its own heat generation :
2CH20+2NaOH+H202=2HC02Na+2H2O-r-H2.
From the back titration of the unused alkali the quantity of formic acid can be
found.
Also, silver oxide or Cu2O generate hydrogen from an alkaline formaldehyde
solution (B. 36, 3304). By the silent electric discharge, formaldehyde is partially
decomposed into CO and H2 (C. 1906, II. 227). H2O2 or BaO2 in acid or neutral
solution change formaldehyde into CO2 and H2 (B. 37, 515).
The estimation can also be carried out by treatment with an alkaline iodine
solution and back titration with thiosulphate (C. 1905, I. 630).
Formaldehyde and sodium sulphite solution unite with liberation of sodium
hydroxide, the titration of when gives the quantity of formaldehyde. This
reaction can also be employed for the estimation of aldehyde polymers (C. 1904,
II. 263).
Dilute solutions of the alkali hydroxides partially transform formaldehyde
into formic acid and methyl alcohol (comp. p. 194 and B. 38, 2556). A modified
aldol condensation occurs with excess of such alkalis as lime, calcium carbonate,
or lead oxide (p. 196), giving rise to glycol aldehyde, C2H4O2, t-arabinose, C6H10O6,
and various hexoses, C,H12O6, of which the principal is a-acrose or \d+I\—
fructose (B. 39, 45, 1592).
This reaction gives a powerful support to the theories of assimilation of carbon
dioxide in plants (B. 3, 67 ; J. pr. Ch. [2] 33, 344).
Formaldehyde, acted on by acetaldehyde and lime yields penta-erythritol,
C(CH8OH)i (U 26, R. 713); with nitromethane (p. 151) it gives nitro-tert.-butyl
ALDEHYDES OF THE SATURATED SERIES
glycerol, NO2C.(CH2OH)3 ; with picoline (Vol. II.) it yields trimethylol-
picoline, (C5H4N)C(CH2OH)3. Thus, formaldehyde shows a strong tendency to
unite repeatedly with reactive CH8- groups, to form aldol-like bodies of increasing
complexity.
In the very numerous reactions of formaldehyde its oxygen unites with two
hydrogen atoms of the reacting body to yield water. It is immaterial whether
the hydrogen is in union with carbon, nitrogen, or oxygen. The products are
diphenylmethane derivatives, methylene aniline, and formals of polyhydric
alcohols (A. 289, 20).
Polymeric Modifications of Formaldehyde. — The concentrated aqueous solution
/"\TT
of formic acid not only contains volatile CH2O, but also the hydrate CH2<QH«
i.e. hypothetical methylene glycol, and non-volatile polyhydrates, e.g.
(CH2)aO(OH)2, corresponding with polyethylene glycols. Therefore the determi-
nations of the molecular weight of the solution, by the method of Raoult, have
yielded different values (B. 21, 3503 ; 22, 472). On complete evaporation of
the solution the hydrates condense to the solid water-soluble paraformaldehyde,
(CH2O)n, possibly diformaldehyde, (CH2O),t.
Trioxymethylene, (CH2O)3, Metaformaldehyde (Butlerow), m.p. 171-172°,
is distinguished from the so-called paraformaldehyde, whose simplicity has not
yet been established, by its insolubility in water, alcohol, and ether. It is
obtained by the action of silver oxide on methylene iodide, or by heating methy-
lene diacetate ester with water to 100° : by distilling gly collie acid with a little
concentrated sulphuric acid, and by passing monochloracetic acid through a
red-hot tube (C. 1898, I. 372). It is a white, indefinitely crystalline mass. The
vapours have the formula CH2O, which corresponds with their density. When
cooled they again condense to the trimolecular form. When it is heated with
water to 130° it changes to the simple molecule CH2O, but by prolonged heating
carbon dioxide and methyl alcohol are produced (B. 29, R. 688).
When dry trioxy methylene is heated with a trace of sulphuric acid to 115°
in a sealed tube it is changed into the isomeric a-Trioxy methylene, (CH,O)8, m.p.
60-61° (B. 17, R. 567).
The polymeric modifications of formaldehyde have not yet been as success-
fully studied as the polymeric acetaldehydes (C. 1904, II. 21, 585).
In contact with peroxide, such as BaO2 and SrO2, and in the presence of
water, the polymerized formaldehydes are catalytically changed into the simple
form, accompanied by the disengagement of a considerable quantity of heat
(0.1906,11.1135).
Acetaldehyde, Ethyl Aldehyde, Ethylidene Oxide [Ethanal], C2H4O
= CH3.CHO, m.p. -120°, b.p. 20-8°, D0=o'8oo9 (B. 23, 638), is
prepared according to the usual methods : (i) From ethyl alcohol
(2) from calcium acetate ; (3) from acetyl chloride or acetic anhydride
(4) from ethylidene chloride from acetal and ethylidene diacetate
(5) from ethylene oxide ; (6) from lactic acid ; (7) from sodium nitro-
e thane ; and (8) from acetylene (p. 86). It occurs in the first
runnings in the rectification of spirit, and is formed, too, by the oxida-
tion of alcohol when filtered through wood charcoal (p. 115).
History. — In 1774 Scheele noticed that aldehyde was formed when alcohol
was oxidized with manganese dioxide and sulphuric acid. Dobereiner, however,
was the first to isolate the aldehyde in the form of aldehyde-ammonia, which
he gave for investigation to Liebig, who then established the composition of
aldehyde and showed its relation to alcohol. It was Liebig who introduced
the name Al(coho\)-dehyd(e)(rogena.tus) into chemical science (A. 14, 133;
22, 273 ; 25, 17). Ordinary aldehyde readily polymerizes to liquid paraldehyde,
and solid metaldehyde. Fehling first observed the former, and Liebig the latter.
Kekult and Zincke determined the conditions of formation for the aldehyde
modifications and cleared up the somewhat confused reaction relations (A. 162,
125).
Preparation. — 90 per cent, ethyl alcohol is oxidized by dropping into it a
200 ORGANIC CHEMISTRY
mixture of a solution of 3 parts of potassium dichromate in 12 parts of water
and 4 parts of concentrated sulphuric acid (B. 27, R. 471). The escaping aldehyde
vapours are conducted into an ethereal solution of ammonia, when the aldehyde-
ammonia separates in a crystalline form. Pure aldehyde may be liberated
from this by dilute sulphuric acid, and dried over dehydrated calcium chloride.
Acetaldehyde is a mobile, peculiar-smelling liquid, miscible in all
proportions with water, ether and alcohol. It is prepared techni-
cally in order to obtain par aldehyde and quinaldine (q.v.).
Polymeric Aldehydes. — Small quantities of acids (HCI, SO,) or salts (especially
ZnCl2, CH3CO2Na) convert aldehyde at ordinary temperatures into paraldehyde,
(C2H4O)S) m.p. 124°, D20=o-9943; the change is accompanied by evolution of
heat and contraction in volume and is particularly rapid, if a few drops of
sulphuric acid be added to the aldehyde. Paraldehyde is a colourless liquid,
and dissolves in about 12 vols. H2O ; it is, however, more soluble in the cold
than when warm. This behaviour would point to the formation of a hydrate.
The vapour density agrees with the formula C6H12O3. Paraldehyde is employed
in medicine as a soporific. When distilled with sulphuric acid ordinary aldehyde
is generated. Bromine at o° enters the molecule without disturbance, forming
parabromacetaldehyde (C. 1900, I. 1201).
Metaldehyde, (C2H4O)3 or (C2H4O)4 (C. 1902, II. 1096), is produced by the
same reagents (see above) acting on ordinary aldehyde at temperatures below o°.
It is a white crystalline body, insoluble in water, but readily dissolved by hot
alcohol and ether. If heated to 1 12°— 1 15° it sublimes without previously melting,
and passes into ordinary aldehyde with only slight decomposition. When heated
in a sealed tube the change is complete. Exposed for several days to a tempera-
ture varying from 60° to 65°, metaldehyde passes into aldehyde and paraldehyde
(B. 26, R. 775).
Chemical behaviour, refractive power, and specific volume point
to a single linkage of oxygen and carbon ; therefore the three oxygen
atoms unite the three ethylidene groups to a ring of six members :
CH3.CH<°— cH(CH3)>0 (R 24' 65° ; 25» 3316 > 26, R. 185).
They may be considered cyclic ethers of ethylidene glycol, of which
the anhydride is acetaldehyde.
Behaviour of Acetaldehyde (Paraldehyde and Metaldehyde). (i) In the air
acetaldehyde slowly oxidizes to acetic acid, It produces a silver mirror from an
ammoniacal silver nitrate solution. Paraldehyde and metaldehyde do not
reduce silver solutions. (2) Alkalis convert acetaldehyde into aldehyde resin.
(3) It is changed to ethyl alcohol by nascent hydrogen. (4) Aldehyde unites
with alcohol to form acetal (p. 205). (5) Hydrogen sulphide converts it into
ihioaldehyde (p. 208), and with mercaptans it forms mercaptals (p. 209). (6) Acetic
anhydride changes it to ethylidene diacetate (p. 207). (7) On shaking aldehyde
with a very concentrated solution of an alkali bisulphite crystalline compounds
separate, CH3.CH(OH)SO3K, which are resolved into their components when
treated with acids (p. 207) :
CH3.CHO+HKSO3=CH3.CH<^K
Paraldehyde and metaldehyde do not unite with the bisulphites of the alkalis.
(8) Acetaldehyde reacts with ammonia, hydroxylamine, and phenylhydrazine,
whilst paraldehyde and metaldehyde fail to do so. (9) Phosphorus pentachloride
converts acetaldehyde, paraldehyde and metaldehyde into ethylidene chloride
-e F°r ihe condensation of aldehyde to aldol, crotonaldehyde, and other compounds,
TRICHLORACETALDEHYDE
201
Aldehyde combines with hydrocyanic acid, the product being the nitrile of
the lactic acid of fermentation, which may be synethesized in this manner.
The homDiogues of formic and aestaldehydes are prepared either (i) by the
oxidation of the corresponding primary alcohols ; or (2) by the distillation of the
calcium or barium salts of the corresponding fatty acids, mixed with calcium or
barium formate ; (3) by transformation of ethylene oxide or glycol ethers ; (4) by
organo-magnesium synthesis ; and (5) from the next higher a-hydroxy-fatty acid
(C. 1904, II. 509).
Name.
Formula.
M.P.
B.P.
Propyl Aldehyde [Propanal]
CHSCH2.CHO
_
49°
n-Butyl Aldehyde [Butanal] . . .
(CH3)(CH2)2.CHO
—
75°
Isobutyl Aldehyde [Methyl Propanal] .
n-Valeraldehyde [Pentanal] ....
(CH8)8CH.CHO
(CH3)[CH2]3CHO
—
61°
103°
Isovaleraldehyde [2-Methvlbtitanal (^)j
C4H9CHO
—
92°
Methyl Ethyl Acetaldehvde . . .
C4H9CHO
—
91°
Trimethyl Acetaldehyde"(B. 24, R. 898)
(CH3)3C.CHO
—
74°
n-Capric Aldehyde
CH3 [CH8]4CHO
128°
Methyl n-Propyl Acetaklehyde .
C6HnCHO
—
116°
Isobutyl Acetaldehyde
CgHnCHO
, _,
121°
CEnanthyl Aldehyde, (Enanthol . . .
CH,[CH2]6CHO
—
155°
[Octanal], C8H16O ....
Capric Aldehyde, C10H20O . . .
CH3[CH2]6.CHO
CH3[CH2]8CHO
__
8i°(32mm.)
106° (15 mm.)
[Undecanal], C^H^O . . .
CH3[CH2]9.CHO
-4°
H7°(i8mm.)
Laurie Aldehyde, C12H24O . . .
CH3[CH2]]0CHO
44'5°
142° (22 mm.)
[Tridecanal], C,3H26O
CHgCCHJjj.CHO
152° (24mm.)
Myristic Aldehyde, C]4H28O . . .
[Pentadecanal], C16H30O . . .
CH3[CH2]12CHO
CH3[CH2]13.CHO
52'5°
i68°(22mm.)
185° (25 mm.)
Palmitic Aldehyde, CjeH82O . . .
CH3[CH2]14CHO
58-5°
192° (22 mm.)
Margaric Aldehyde, C17H 3 4O . . .
CH8[CH2]15CHO
36°
204° (26 mm.)
Stearic Aldehyde, C18H86O . . .
CH3[CH2]16CHO
63-5°
212° (22 mm.)
Propyl aldehyde, by the action of hydrochloric acid, yields both paraprof>yl
aldehyde, b.p. 169°, and metapropyl aldehyde, m.p. 180°. They have the
molecular formula (C3H8O)3 (B. 28, R. 469).
GEnanthylie Aldehyde, (Enanthol (olvos, wine), is very readily prepared.
It is formed together with undecylenic acid when castor oil is distilled under
diminished pressure :
C18H3403 = C10H19.C02H+CH3.[CH2]5CHO.
Ricinoleic Undecylenic (Enanthol.
Acid. Acid.
I. HALOGEN SUBSTITUTION PRODUCTS OF THE SATURATED ALDEHYDES
The most important member of this class of substances is Trichlor-
acetaldehyde, Chloral, CC13.CHO, b.p. 97°, D0= 1*541, was discovered
in 1832 by Liebig while engaged in studying the action of chlorine
on alcohol (A. 1, 182).
. Fritsch considers that chlorine acts on alcohol to produce at first mono-
chloralcohol or aldehyde chlorhydrin (i). Alcohol and hydrochloric acid convert
this, through the aldehyde alcoholate, into acetal. Neither substance can be
isolated. Obviously acetal is chlorinated too easily to mono- and dichloracetal
(n. and in.). These two compounds, under the influence of hydrochloric aciA, pass
into dichlor- and trichlor-ether (iv. and v.). Water changes the latter to dichlor-
acetaldehyde alcoholate (vi.)f which is converted by chlorine into chloral alco-
holate. Sulphuric acid decomposes the latter into alcohol and chloral (vui.)
202
ORGANIC CHEMISTRY
(A. 279, 288 ; C. 1897, I. 635, 801 ; compare also the chlorination of isobutyl
alcohol, B. 27, R. 507).
CH,.CH2OH
CH3.CH<°H
IV
25 Hcl CH Cl
2H5 > *
CHC12CH<°C2H
VIII
CC13.CHO
Chloral hydrate, dichlor acetic ester, trichlor-ethyl alcohol (B. 26, 2756), andethylene
monochlorhydrin are by-products in the manufacture of chloral. (Private com-
munication from Anschutz and Stiepel.)
Chloral is an oily, pungent-smelling liquid. When kept for some time
it passes into a solid polymer.
Chloral shows greater tendency than acetaldehyde to sever its double linkage,
between carbon and oxygen, and to enter into addition-reactions. Like acetalde-
hyde it not only combines with acetic anhydride, the alkali bisulphites, ammonia
and hydrocyanic acid, but also with water, alcohol, hydroxylamine, formamide—
four substances with which acetaldehyde is incapable of uniting.
The following reactions of chloral should also be observed : (i) The alkalis
break it down into chloroform and alkali formates ; (2) fuming sulphuric acid
condenses it to chlorolide (q.v.), trichlorolactic trichlorethylidene ether ester;
(3) potassium cyanide changes it to dichloracetic ethyl ester (q.v.) :
(1) CC13CHO+KOH=HC.C13-1-H.C02K.
(*(~\(~\
(S03 + H2S04) . >CH.CC18.
(2) 3CC1,.CHO - - — — ^HCCls+CClaCHCT
Chloralide.
Chloral Hydrate, Trichlorethylidene Glycol, CC18.CH<Q§, m.p. 57°,
b.p. 96-98°, results from the union of chloral with water. It is
technically prepared on a large scale. It consists of large monoclinic
prisms. The vapours dissociate into chloral and water. Chloral
hydrate dissolves readily in water, possesses a peculiar odour and a
sharp, biting taste ; when taken internally it produces sleep, a fact
which was discovered in 1869 by Liebreich (B. 2, 269). It occurs in
urine as urochloralic acid (q.v.). Concentrated sulphuric acid resolves
the hydrate into water and chloral. It reduces ammoniacal silver
solutions and when oxidized with nitric acid yields trichloracetic
acid.
PEROXIDES OF THE ALDEHYDES 203
In chloral hydrate is found the first example of a body which, contrary to
the rule, contains two hydroxyl groups attached to the same carbon atom, without
the occurrence of the immediate spontaneous cleavage of water.
Other Halogen Substitution Products of Acetaldehyde. — Dichloracetaldehyde,
b.p. 88-90°, results from the action of concentrated H2SO4, or better, benzoic
anhydride (B. 40, 217), on dichloracetal, CHC12.CH(OC2H6)2. Dichloracetalde-
hyde Hydrate, CHCla.CH (OH)2, m.p. 57° and b.p. 120°. Monochloracetaldehyde,
b.p. 85°, is formed when monochloracetal (p. 205) is distilled with anhydrous
oxalic acid. It polymerizes very readily (B. 15, 2245).
Tribromaldehyde, Bromal, CBr3.CHO, b.p. 172-173°, is perfectly analogous
to chloral. Heated with alkalis, bromal breaks up into bromoform, CHEr3,
and a formate.
Bromal Hydrate, Tribromethylidene Glycol, CBr3CH(OH)2, m.p. 53°.
Bromal Alcoholate, CBr3CH(OH)(O.C2H5), m.p. 44°.
Dibromacetaldehyde Hydrate, CHBr2CH(OH)2, m.p. 59°, is prepared by the
addition of HBrO to acetylene (C. 1900, II. 29).
Dibromacetaldehyde, b.p. 142°, is obtained by the bromination of paraldehyde.
Bromacetaldehyde, b.p. 80-105°, is produced, like monochloracetaldehyde,
from monobromacetal.
Mono-iodoacetaldehyde, CHJ.CHO, is made by acting on aldehyde with
iodine and iodic acid. It is an oily liquid, which decomposes at 80° (B. 22, R. 561).
The relations of the three chlor- (or brom-) acetaldehydes to the
oxygen derivatives, of which they may be considered the chlorides,
are shown in the following arrangement (p. 196) :
CHjCl.CHO, Chloracetaldehyde. CH2(OH).CHO, Glycolyl Aldehyde.
CHC12.CHO, Dichloracetaldehyde. CHO.CHO, Glyoxal.
CC13.CHO, Trichloracetaldehyde. CO8H.CHO, Glyoxylic Acid.
Higher Chlorine Substitution Products of the Aldehydes :
fi-Chloropropionic Aldehyde, CHaCl.CH2.CHO, m.p. 35°, from acrolein,
CH2=CH.CHO, and hydrochloric acid.
fi-Chlorobutyr aldehyde, CHS.CHC1.CH2.CHO, m.p. 96°, is produced from croton-
aldehyde, CH3.CH : CH.CHO, by the addition of HC1.
arf-Trichlorobutyraldehyde, Butyl Chloral, CH3.CHCl.CCla.CHO, b.p. 163-165°
(comp. acetamide).
Butyl Chloral Hydrate, CH3CHC1.CC12.CH(OH)2, m.p. 78°, is formed from a-
chlorocrotonaldehyde and C12. Alkalis decompose it into formic acid, potassium
chloride, and dichloropropylene,CH3. CC1 : CHC1. When taken into the system it
appears in the urine as urobutyl chloralic acid (q.v.), and is converted, by nitric
acid, into trichlorobutyric acid.
The relations of these three chlorinated aldehydes to the unsaturated aldehydes,
from which they are formed by the addition of HC1 or C12, and to the acids which
they yield on oxidation, are shown in the following table : —
HC1 HN03 ft •
CH2=CH.CHO > CH2C1.CH2.CHO > CH2C1.CH2.CO2H.
Acrolein. ^-Chloropropionaldehyde. j8-Chloropropionic Acid.
HC1
CH3.CH=CH.CHO > CH3.CHC1.CH2CHO > CH3.CHC1.CH2.CO2H.
CrotonaUehyde. /3-Chlorobutylaldehyde. /3-Chlorobutyric Acid.
CHS.CH=CC1.CHO V CH3.CHC1.CC12.CHO > CH8.CHC1.CC12.CO2H.
a-Chlorocrotonaldebyde. Butylchloral. Trichlorobutyric Acid.
Tetrabromobulyric Aldehyde, CH3Br.CHBr.CBr2CHO, m.p. 64°, b.p.18 146°,
is prepared from paraldehyde and excess of bromine, with the intermediary
production of crotonaldehyde. It does not form a hydrate, and is decomposed
by alkalis into formic acid, bromopropargyl bromide, H2CBrC;CBr, and other
bodies (C. 1905, II. 392 ; 1907, I. 1180).
PEROXIDES OF THE ALDEHYDES
Formaldehyde peroxide: Diformal Peroxide Hydrate, HOCH2O.OCH2OH, m.p.
51°, occurs during the slow combustion of ethyl ether (B. 18, 3343). Ammonia
204 ORGANIC CHEMISTRY
changes it into Hexaoxymethylene Diarnine, Hexamethylene Triperoxydiamine,
N(CH2O.OCH2)SN, which can also be easily prepared by the action of a solution
of formaldehyde on ammonium sulphate dissolved in 3 per cent, hydrogen peroxide.
The dry substance explodes as violently as diazobenzene nitrate on being heated,
by friction or by a blow (B. 33, 2486).
Acetaldehyde Peroxide has not, as yet, been closely investigated.
Diehloral Peroxide Hydrate, CCl3CH<Q^~^Q>CH.CC]3,m.p. 122°, is prepared
from chloral and H2O2 in an ether solution or potassium persulphate in sulphuric
acid (B. 33,2481).
On the Oxonides of the aldehydes, comp. also A. 343, 326.
2. ETHERS AND ESTERS OF METHYLENE AND ETHYLIDENE GLYCOLS
In the introduction to the aldehydes (p. 189) it was explained that these bodies
could be regarded as anhydrides of glycols, only capable of existing in excep-
tional cases. In the latter the two hydroxyl groups were linked to the same
terminal carbon atom. Stable ethers and esters of these hypothetical glycols are,
however, known.
These hypothetical glycols might also be designated orthoaldehydes, because
they bear the same relation to the aldehydes that the hypothetical orthocarboxylic
acids sustain to the carboxylic acids :
OH XOH /OH
CH,<™ CH20 CH^-OH CH^
\OH ^O
Orthoiormaldehyde. Formaldehyde. Orthoformic Acid. Formic Acid.
Basic and neutral mono- and dialkyl-ethers may be obtained from a dihy-
droxy-alcohol. The only mono-ether to be noticed in this connection is chloral
alcoholate, which is mentioned under chloral hydrate :
« ccl»CH<oc2H'-
Chloral Hydrate. Chloral Alcoholate. Trichloracetal.
Alcohols not highly substituted by halogens are as little able to combine with a
molecule of alcohol as with water. The dialkyl ethers are named acetals, from
their best-known representative. They are isomeric with the ethers of the corre-
sponding true glycols, whose OH-groups are attached to different carbon atoms :
/O.C2H, CH2.O.C2H,
CH,.CH< |
NO.C2H, CH2.O.C2HB
Acetal. Glycol Diethyl Ether.
A. Aleoholates or Carbinolates of this type can only exist as addition products
of alcohol with halogen substitution products of the aldehydes. In this they
resemble the ethylidene glycols or aldehyde hydrates which are only stable when
a sufficient number of hydrogen atoms have been replaced by halogens.
Chloral Alcoholate, CC1SCH<Q^ H , m.p. 65°, b.p. 114°, is the main product
from the action of chlorine on alcohol (p. 201). It is also formed by treatment of
chloral or chloral hydrate with alcohol. Water changes it slowly into chloral
hydrate (B. 28, R. 1013). Chloral Dimethyl Ethyl Carbinolate, CC18CH(OH).-
OC(CH,)2C2H6, is prepared from chloral and amylene hydrate (p. 121), or chlorine,
amylene and hydrochloric acid (C. 1900, II. 1167).
B. Acetals are produced (i) when alcohols are oxidized with MnO2and H2SO4.
The aldehyde formed at first unites with alcohol with the simultaneous separation
of water :
3CH,.CH2OH ^CH,CH(O.C2H,)2+2H2O.
(2) When aldehydes are heated with the alcohols alone to 100° ; and from
trioxymethylene and alcohols on the addition of ferric chloride (1-4 per cent.)
(B. 27, R. 506), or syrupy phosphoric acid (C. 1899, I. 910).
DIHALOGEN ALDEHYDES, ALDEHYDE HALOHYDRINS 205
(3«) By the action of gaseous IIC1 on a mixture of alcohol and aldehyde,
chlorhydrin (see Ethylene Glycol) being the first product :
CH8CHO+CaHBOH
(36) More suitably, by the action of I per cent, alcoholic hydrochloric acid
on aldehyde (B. 31, 545).
(4) By the action of metallic alcoholates on the corresponding chlorides,
bromides and iodides.
(5) By the action of aldehydes on orthoformic ester or hydrochloric acid,
formimido-ether and alcohol, i.e. on nascent orthoformic ester. This method is
also employed for the preparation of acetal of the ketones (B. 31, 1010 ; 40, 3301).
On heating the acetals with alcohols, the higher alkyls are replaced by the
lower (A. 225, 265; C. 1901, I. 1146). When the acetals are digested with
aqueous hydrogen chloride they are resolved into their constituents. They
dissolve readily in alcohol and in ether, but with difficulty in water.
The acetals are considerably more stable towards alkalis than the
aldehydes, and are mainly employed in those changes where aldehydes
would be resinified or condensed.
Methylal, Methylene D imethyl Ether, Formal, CH2(OCH3)2,b.p. 42°, D. =0-855,
is an excellent solvent for many carbon compounds. Methylene Diethyl Ether,
Diethyl Formal, CH2(OC2H5)a, b.p. 89°. For the higher methylals see B. 20,
R- 553 ; 27, R. 507. Dichloromethylal, CHa(OCH2Cl)2, b.p. 166°, is obtained
from the interaction of paraformaldehyde and dichloromethyl ether, O(CHaCl)a ;
and also from a formaldehyde solution and HC1 (A. 334, i). With sodium meth-
oxide and eth oxide it yields respectively Dimethoxymethylal, b.p. 107°, and
Diethoxymethylal, b.p. 140°, having the general formula CH2(OCH2OR)2 (C. 1904,
II. 416, 1906, II. 226).
Ethylidene Dimethyl Ether, Dimethyl Acetal, CH3CH(OCH3)2, b.p. 64°.
Acetal, Ethylidene Diethyl Ether, CH3CH(OC2H5)2, b.p. 104°,
D20 =0*8314, is produced in the process of brandy distillation. It is
quite stable towards the alkalis, whilst dilute acids readily break it
down into aldehyde and alcohol (B. 16, 512).
Chlorine acting on acetal produces —
Monochloracetal, CH2C1.CH(O.C2H6)2, b.p. 157° (B. 24, 161), results from
Dichlorether, CH2C1.CHC1.OC2H6, and alcohol or sodium ethoxide (B. 21,617);
also from paraldehyde chlorine, and alcohol (for references, see Monobromacetal,
below).
Dichlor acetal, CHCla.CH(O.C2H6)2, b.p. 183-184°.
Trichloracetal, CC1S.CH(OC2H6)2, b.p. 197°, is prepared from alcohol and
chlorine.
Monobromacetal, CHaBrCH(OC2H8)2, b.p. 170°, is produced from acetal,
bromine, and CaCO3; or from paraldehyde, bromine, and alcohol (B. 25, 2551;
C. 1905, I. 1218; 1907, I. 1180). Sulphuric acid decomposes the chlorinated
acetals into alcohol and chlorinated aldehydes (p. 196).
lodoacetal, I.CH2.CH(OCaH6)2, b.p.18 100° (B. 30, 1442). Butyl Chloral-
acetal, CHsCHCl.CClaCH(OCaH6)2, b.p.,0 123° (C. 1907, I. 152).
The polymeric modifications of aldehyde are closely related to the acetals,
and result from an acetal-like union of similar molecules (p. 196). If molecules of
different aldehydes take part in the reaction, there are obtained compounds
similar to those formed by the polymeric aldehydes ; chloral and formaldehyde, with
Q>CHCla (B. 33, 1432).
C. Dihalogen Aldehydes and Aldehyde Halohydrins their Alkyl Ethers and
Anhydrides.
In describing the dihalogen substitution products of the paraffins it was
indicated that compounds in which two halogen atoms occur joined to the same
terminal carbon atom bear an intimate genetic relation to the aldehydes, and are
therefore called aldehyde dihalides.
206
ORGANIC CHEMISTRY
If these compounds be referred to glycols containing two hydroxyl groups
attached to the same terminal carbon atom, — i.e. the hypothetical ortho-alde-
hydes, — then the aldehyde halides are the neutral haloid esters of these glycols.
Between the ortho-aldehydes and the aldehyde halides stand the monohaloid
esters, the aldehyde halohydrins, isomeric with the monohaloid esters of the true
glycols, — the glycol halohydrins, — but only known in the form of their alkyl ethers,
the a-monohaloids, ordinary ethers and their anyhdrides, the symmetrical a-disub-
stituted, ordinary ethers :
CH/
H
CH
CH
>J
CH3
H
^
CH*<C1
/O
CH<
| XC1
CHS
/
CHC1.CH3
CHC1,
|
CH,
The genetic relations of the aldehyde halides to the aldehydes consist in the
formation of aldehyde chlorides from the aldehydes by means of PC16, and the
change undergone by the aldehyde chlorides when heated to 100° with water.
i. Aldehyde Dihalides. — The boiling points, melting points, and specific
gravities of some of the simple aldehyde dihalides are given in the appended table.
The inclosed numbers after the boiling points indicate diminished pressure :
Name.
Formula.
M.P.
B.P.
D.
Methylene Chloride .
CH2C18
.. .
41°
1-37 ( o°)
Methylene Bromide .
CH2Br2
—
98°
2'54 ( o°)
Methylene Iodide
CH2I2
+ 4°
181°
3-28 (15°)
Ethylidene Chloride .
CH3CHC1,
60°
I-I7 (20°)
Ethylidene Bromide — .
CH3CHBr2
—
110°
2-Q2 (20°)
Ethylidene Iodide
CH3CHI2
—
127° (171)
2*84 ( o°)
Propylidene Chloride
CH3.CH2CHC12
~~"~
86°
1-16 (14°)
Methylene Chloride is formed from CH3C1 and Cl, by the reduction of
chloroform by means of zinc in alcohol, and from trioxymethylene and PC16.
Methylene Bromide results on heating CH3Br with bromine to 180°, and by
the action of trioxymethylene on aluminium bromide, or phosphorus penta-
bromide.
Methylene Iodide is produced when iodoform is reduced with HI, or better,
with arsenious acid and sodium hydroxide (Klinger). It is characterized by a
high specific gravity. Chlorine and bromine change it to methylene chloride and
bromide (comp. ethylene, p. 80). Mercury changes it into ICH2HgI (C. 1901, 1.1264).
Ethylidene Chloride, Aldehyde Chloride, is produced (i) from aldehyde by
the action of PC16, (2) from vinyl bromide by means of hydrogen bromide, and
(3) by treating copper acetylide with concentrated hydrochloric acid (A. 178, in)
(comp. Ethylene, p. 80).
Ethylidene Bromide is obtained by the action of PCl,Bra on aldehyde
(B. 5, 289).
Ethylidene Iodide is obtained from acetylene and hydriodic acid (B. 28,
R. 1014).
2. Alkyl Ethers of the Aldehyde Halohydrins, a-Monohaloid Ethers result
from the action of alcohols and haloid acids on the aldehydes. Alcohols
or alcoholates readily convert them into acetals. Monochloromethyl Ether,
CH2<£jC«H«, b.p. 60°; D16 = i-i5o8. Monochloromethyl Propyl Ether,
C1CH2OC3HT, b.p. 105-110°, and higher homologues are obtained from trioxy-
methylene hydrochloric acid and methyl, ethyl, propyl, etc., alcohol (A. 334, 49 ;
B. 36, 1383). They are highly reactive bodies ; with water they regenerate
formaldehyde ; with formates and acetates they yield ether -esters of the type
HCOOCHjOR; with magnesium alkyl halides they give simple ethers (p. 126);
with magnesium in presence of ketones or carboxylic esters or magnesium-organic
compounds such as ROCH2MgX (p. 186), they form ethers of the ethylene glycols,
DIHALOGEN ALDEHYDES, ALDEHYDE HALOHYDRINS 207
R"R'C(OH)CH2OR,or diethers of the g/ycm>/s,R'C(OH)(CH2OR)2 ; withmercury
or copper cyanides they are converted into nitriles of alkoxyl glycollic acid
NC.CH2OR (C. 1907, I. 400, 871). They yield hexamethylene tetramine with
ammonia (p. 210), and form quaternary ammonium salts, ClR3NCHaOCH8,
with tertiary amines. Monobromomethyl Ether, b.p. 87°; D.12 = i'53i. Mono-
iodomethyl Ether, b.p. 124° ; Dlt=2-o249 (B. 26, R. 933).
a-Monochlor ethyl Ether, CH3CHCl.O.CHaCH8, b.p. 98°, isomeric with ethylene
chlorohydrin ethyl ether, C1CH2CH2.O.C2H5, is produced by the chlorination of
ether, and by saturating a mixture of aldehyde and alcohol with hydrochloric
acid, into which substances it is again resolved by water. Monobromethyl Ether,
b.p. 105° (B. 18, R. 322).
3. Sym. aa'-Dihalogen Alkyl Ethers, Ethers of the Aldehyde Halohydrins.
The symmetrical dihalogen methyl ethers result from the action of the halogen
acids on trioxymethylene (C. 1900, I. 1122; 1901, II. 26; A. 334, i). sym.-
Dichloromethyl Ether (CH2C1)2O, b.p. 105°, 0 = 1-315, is also obtained, together
with dichloromethylal from trioxymethylene and PC18. sym.-Dibromomethyl
Ether, b.p. 150°. sym.-Di-iodomethyl Ether, b.p. 218°.
D. Carboxylic Esters of Methylene and Ethylidene Glyeols are formed (i) from
aldehydes and acid anhydrides ; (2) from aldehydes and acid chlorides ; (3) from
the corresponding chlorides, bromides, and iodides by the action of silver salts.
When boiled with water these esters break down into aldehydes and acids :
i. CH8CHO + (CH3CO)aO =CH3CH(OCOCH8)2.
2. CH8CHO+CH8COC1 =C
3. CH2I2+2CH8CO2Ag=CH2(OCOCH8)t+2AgI.
Methylene Diacetate, CH2(OCOCH3)2, b.p. 170°. For higher homologues see C.
1902, II. 933 ; 1903, II. 656: Ethylidene Diacetate, CH8CH(O.COCH8)2, b.p. 169°.
Chloral Diacetate, CC13.CH(OCOCH3)2, b.p. 221°. Bromal Diacetate, m.p. 76°.
Monochloromethyl Acetate and Monobromomethyl Acetate, Br.CH2OCOCH8,
b.p. 130°, are prepared from trioxymethylene and acetyl chloride or bromide
(C. 1901, II. 396). Ethylidene Chlorhydrin Acetate, Monochlor ethyl Acetate,
CH3CHC1.OCOCH8, b.p. 121 '5°, is the parent substance for the preparation of
ether-esters and mixed ethers, Ethylidine Chlorhydrin Propionate, b.p. 134—136°.
Silver propionate with the first Chlorhydrin forms the same Aceto-ethylidine
Propionate, CH8COO.CH(CH3)OCOC2H6, b.p. 178-6°, as silver acetate with the
second Chlorhydrin. These facts argue for the equivalence of the carbon valencies
(Geuther, A. 225, 267).
Chloral Acetyl Chloride, CC13CHC1(OCOCH3), b.p. 193°.
Bromal Acetyl Chloride (C. 1900, II. 811).
Chloral Ethyl Acetate, CCl8.CH(OCaH6)OC2O.CH8, b.p. 198° (G. 1901, I. 930).
E. Aldehyde Bisulphites and Sulphoxylates.
The aldehydes in aqueous solutions absorb sulphurous acid with the evolution
of heat (B. 38, 1076 ; C. 1904, II. 54, etc.). On evaporation the gas is driven off ;
but if bisulphite salts are added in the first place this does not occur, and
crystallizable salts are obtained of the general formula RCHOHSO8Me. The
bisulphites serve to characterize the various aldehydes.
Previously these compounds were considered as being a-hydroxy-alkyl
sulphonic acids. However, a comparison between hydroxy-methyl sulphonic
acid (p. 210), obtained from the methyl alcohol, with formaldehyde shows at once
that great differences exist. The first-named acid and its salts are very stable,
and show little tendency to undergo transformation, whilst formaldehyde
bisulphite and its higher homologues —
(1) are easily decomposed by hydrochloric acid or alkalis, regenerating the
aldehyde ;
(2) are easily transformed by aqueous solutions of alkali cyanides, forming
aldehyde cyanhydrins or o-hydroxyacid nitriles (B. 37, 4060 ; 38, 213).
HO.CH2.S08K+KNC=HOCHaCN + K2S08 ;
(3) are converted by ammonia or amines into alkylidene amino-sulphites
(B. 37, 4075 ; 38, 1077) :
HO.CH,.SO,Na+NH8=NHa.CH2.S08Na+HaO;
(4) yield derivatives of sulphoxylic acids by reduction (p. 208).
From these observations formaldehyde bisulphite and all similar bisulphite
208 ORGANIC CHEMISTRY
addition products of homologous aldehydes are looked upon as being the bi-
sulphites of aldehyde ortho-hydrate, which are isomeric with the a-hydroxy-
sulphonates (comp. p. 210, B. 38, 1069) :
rw .OH PTT /OH
CH»<S08Na UH»^O.S02Na
Sodium Hydroxymethyl Sulphonate. Formaldehyde Sodium Bisulphite.
Neutral sulphites also form aldehyde bisulphites with the liberation of alkali
hydroxide, the titration of which serves as a method of quantitative estima.
tion of the aldehyde (C. 1904, I. 1176, 1457) :
RCHO+S08Naa=RCHO.HSOsNa+NaOH.
Reduction of aldehyde bisulphites by zinc dust and acetic acid leads to the
formation of aldehyde sulphoxylates (B. 38, 1073 ; C. 1905, II. 1752, etc.).
RCH(OH).OSOaNa+2H=RCH(OH).OSONa+H2O.
Formaldehyde Sulphoxylate, HOCHa.OSONa+2HaO, withstands the action
of alkalis better than formaldehyde bisulphite. It forms small rhombic prisms
(C. 1905, I. 795). A finely crystallizing double compound of formaldehyde
sulphoxylate and formaldehyde bisulphite (B. 38, 2290) may be prepared from
formaldehyde and sodium hydrosulphite, NaaSaO4. This body, known under the
name of Rongalite, is of technical importance in the dyeworks where, in discharge
work, the reducing action of sodium hydrosulphite is developed at a raised
temperature and then only acts on the azo-dyestuffs, indigo, etc., without
attacking the fibre. Rongalite can be split up into its constituent compounds
by fractional crystallization. Sulphoxylates react with amines similarly to the
aldehyde bisulphites (p. 207).
3. SULPHUR DERIVATIVES OF THE SATURATED ALDEHYDES
In this class are (A) the thioaldehydes, their polymeric modifications and their
sulphones; (B) the mercaptals or thioacetals, with their sulphones', and (C) the
hydroxysulphonic and disulphonic acids of the aldehydes.
A. Thioaldehydes, Polymeric Thioaldehydes and their Sulphones. — The simple
thioaldehydes are not well known, whilst the polymeric thioaldehydes are more
accessible. All of them can be regarded as the alkyl derivatives of polymeric
trithioformaldehyde, the trithiomethylene, discovered by A. W. Hofmann. They
are formed when the aldehydes are acted on with HaS and HC1. The H2S adds
itself to the C=O-group of the aldehydes, and hydroxy-hydrosulphides result,
from which the trithioaldehydes arise :
r~a r\~ * ^ PTJ- s*SH- . f^ij ^S.CHaSH PTJ /S — CHas. c
CHaO - 'H*<QH > CH«<S.CHaOH > CH*<S— CH3>S'
The trithioaldehydes are odourless solids, whereas the simple thioaldehydes
and their mercaptan-like transposition products possess a persistent, disagreeable
odour. Potassium permanganate oxidizes the trithioaldehydes first to sulphide-
sulphones and then to trisulphones. The molecular weight of the trithioaldehydes
has been determined both by vapour density and by the lowering of the freezing
point of their naphthalene solution. Klinger first proposed the structure for the
trithioaldehydes which corresponds with the formula of paraldehyde and was
proved correct by the oxidation of the trithioaldehydes to trisulphones.
The isomeric phenomena of the trithioaldehydes were considered by Baumann
and Fromm to be due to their space-configurations (B. 24, 1426).
Proceeding from the same considerations, which served Baeyer in his ex-
planation of the isomerism of thehexamethylene derivatives (see Hex a hy drophthalic
Acids), these chemists distinguished a-, cis- or maleinoid and /?, trans- or fumaroid
modifications. Camps represents the spacial difference between the two trithio-
aldehydes in the following way : —
SULPHUR DERIVATIVES OF SATURATED ALDEHYDES 209
The C-atoms are assumed to be in the angles of the triangles, and the S-atoms
are in the middle of the sides. The three alkyl groups are either upon the same
side of the six-membered ring system : a, cis-iorm ; or upon different sides of it :
j3, tows-modification. Only one disulphone-sulphide corresponds with the cis-
modification, whilst two stereoisomeric disulphone-sulphides take the trans-
form. On Klinger's interpretation of these phenomena as " alloergatic isomerism,"
characterized by the various energy-contents of the isomers, compare fumaric and
maleic acids, see B. 32, 2194.
Trithio formaldehyde, [CH2S]3, m.p. 216°, is prepared by boiling together
formaldehyde, sodium thiosulphate, and hydrochloric acid. Probably an inter-
mediate compound formaldehyde thiosulphuric acid, CH2(OH)S.SO8H, is formed,
which breaks up on boiling into thioaldehyde and sulphuric acid (B. 40, 865).
On heating trithioformaldehyde with iodomethane and methyl alcohol, there is
formed trimethyl sulphinium iodide (p. 145 ; C. 1906, I. 649). a-Trithioacetalde-
hyde, m.p. 101°, b.p. 246-247°, and fi-Trithioacetaldehyde, [CH3CHS]3, m.p.
125-126°, b.p. 245-248° ; at low temperatures the a-form predominates, but can
be changed in considerable proportion into the jS-form by the aid of catalysts
such as iodine, zinc chloride, acetyl chloride, hydrochloric acid, etc. (B. 24, 1457 ;
C. 1905, II. 1720 ; compare also C. 1904, II. 21).
Sulphones of the Trithioaldehydes. — The trisulphones, resulting from theoxidation
of the trithioaldehydes, are all to be considered as being alkylated derivatives of
trimethylene trisulphone. The six methylene hydrogen atoms of trimethylene tri-
sulphone are acidic like those of the methylenes in malonic ester (q.v.). They can
be replaced by metals, and hexa-alkylated trimethylene sulphones can be synthe-
tically prepared by the double decomposition of the alkali derivatives with alkyl
iodides. These are identical with the oxidation products of the corresponding
trithioketones. The primary product in the oxidation of a trithioaldehyde is a
monosulphone, the secondary a disulphone, and finally a trisulphone is
produced.
Trimethylene Trisulphone, CH2<|g»~™2>SO2, and Trimethylene Disul-
Qf-x /"^TJ
phone Sulphide, CHa<so2'CH2>S, m.p. above 340°, as is also that of
Triethylidene Trisulphone, [CH3CHSO2]3 (B. 25, 248).
The two isomeric trithioacetaldehydes yield Triethylidene Disulphone Sul-
phide, CH3.CH.<s°*™|£H3j>S, mp 228-231°. "The isomerism of the
trithioaldehydes vanishes in their oxidation products " (B. 26, 2074 ; 27, 1667).
Thialdine,CH3.CH<|^g((^3J>NH, m.p. 43°, is produced by the action of
NH8 on a-trithioacetaldehyde (B. 19, 1830), and of H2S on aldehyde-ammonia
(A. 61, 2). It yields ethylidene disulphonic acid (p. 210) by oxidation. Methyl
Thialdine, (C2H4)3S2(NCH3), m.p. 79° (B. 19, 2378).
B. Mereaptals or Thioacetals and their Sulphones.
The thioacetals, corresponding with the acetals (p. 205), are called mercaptals.
They are formed (i) from alkyl iodides and alkali mercaptides ; (2) by the action
of HC1 on the aldehydes and mercaptans. First an addition product is formed
such as CH2(OH)SCBHn, which with a second mercaptan molecule loses water
and yields a mercaptal. It is possible, therefore, to prepare mercaptals con-
taining two different alkyl groups (B. 36, 296). They are oils with very
unpleasant odours, and are oxidized by KMnO4 to sulphones.
rTT ^S.CZHS 40 ^-SO2.C2HB
CHa<S.C2H6 > CH2<S02.C2H*'
Methylene Mercaptal, CH2(SC2H6)2, b.p. about 180°. Ethylidene Mercaptal,
Dithioacetal, CH3CH(SC2H6)2, b.p. 186°. Propylidene Mercaptal, CH3CH2CH-
(SC2H5)2, b.p. 198°.
In the sulphones of the mercaptals the methylene hydrogen (see above) is
replaceable by akali metals. Mono- and dialkylated sulphones can be prepared
from these akali derivatives. Again, the dialkylized sulphones may be obtained
from the mercaptols (p. 226) ; sulphonal belongs to this class.
Methylene Diethyl Sulphone, CH2(SOaC2H6)2, m.p. 104°, is readily soluble in
water and in alcohol. It is formed in the oxidation of orthothioformic ethyl ester
(q.v.). It condenses with formaldehyde, forming methylene dimethenyl tetraethyl
VOL. I. P
210 ORGANIC CHEMISTRY
sulphone (B. 33, 1120). Methylene Ethyl Phenyl Disulphone, CH2(SO2C2H,)
(SO2CBHB),m.p. iii°(B.36,30o). Ethylidene Diethy I Sulphone ,CH,CH(SO2C2H,),,
m.p. 75°, b.p. 320° with decomposition.
C. Hydroxysulphonic Acids and Disulphonic Acids of the Aldehydes.
Hydroxymethyl Sulphonic Acid, CH2(OH)SO8H, is formed together wit)
Hydroxymethylene Disulphonic Acid, CH(OH)(SO3H)2, and Methine Trisulphoni
Acid, CH(SO3H)3, by the action of fuming sulphuric acid on methyl alcohoi
and subsequent boiling of the product with water. Boiling acids or alkalis have
no effect on it (comp. p. 208).
Methionic Acid, Methylene Disulphonic Acid, CH2(SO3H)2, has long been
known. It is produced when fuming sulphuric acid acts on acetamide. aceto-
nitrile, lactic acid, etc. It is most conveniently made by saturating fu aiing sul-
phuric acid with acetylene (from calcium carbide), but acetaldehyde disulphonic
acid, CHO.CH(SO3H)2 is the main product of reaction.
This acid can be completely decomposed by alkalis into formic and methionic
acids :
0(S03H)2 H.O
CH; CH ^OCH.CHfSOgH,) ^H02CH+CH2(S03H)2
Acetylene. Acetaldehyde Formic Methionic
Disulphonic Acid. Acid. Acid.
Methionic acid crystallizes in deliquescent needles, which are not decomposed
by boiling nitric acid. Barium salt, CH2(SO3)2Ba-f-2H2O, forms pearly leaflets
dissolving with difficulty.
Methionic Methyl Ester, CH2(SO3CH3)2, m.p. 70°, b.p.16 194-200° : ethyl ester,
m.p. 29°, results from the action of silver methionate on iodoalkyls, and is easily
hydrolyzed by water. Methionyl Chloride, CH2(SO^Cl)z, b.p.10 i35°,D.15=i-82, is
formed from methionic acid and phosphorus pentachloride. It reacts energeti-
cally with water or alcohol, regenerating methionic acid. With amines, especially
those of the aromatic series, it forms amides.
Methionic Anilide, CH2(SO2NHC,H6)2, m.p. 193°, yields well crystallizable or
insoluble salts: CH2(SO2NMeC,H6)2. Methionic Z)i^ytam7t^,CH2(SO2H[C2H6]-
CeH,)2, m.p. 113*
The esters, still better the dialkyl amides of methionic acid, react with
potassium and sodium, evolving hydrogen and forming salts, KCH(SO3R)2 and
NaCH(SO2NR2)2 which readily undergo transformation with alkyl halides,
acyl halides and carboxylic esters. As a result, homologues of methionic acid can
be formed in the same way as malonic ester is caused to yield its homologues
(Communication from G. Schroeter : comp. also B. 38, 3389) :
C2H.I
NaCH(SO2NR2)2 i-L> C2H5CH(SO2NR2)2 > C2H6CH(SO3H)2
Ethyl Methionic Acid.
CH,CNa(S02NR2)a -f^V CCH3>C.(SO2NR2)2 >- CC^3>C(SO3H)2
"2 Ethyl Methyl
Msthionic Acid.
Ethylidene Disulphonic Acid, Methyl Methionic Acid, CH8CH(SO8H)2, is also
formed from thialdine (p. 209) by oxidation with permanganate (B. 12, 682 ;
21, 1550).
4. NITROGEN DERIVATIVES OF THE ALDEHYDES
A. Nitro-Compounds. — Bromonitromethane, and i,i-Bromonitroethane and
"propane, as well as i,i-Dinitroparaffins (p. 154), diisonitramines (p. 154) and
the salts of the aci-nitroparaffins (p. 150), which have been previously described,
must be regarded as nitrogen derivatives of aldehyde.
B. Ammonia and Monalkylamine Aldehyde Derivatives (p. 195). —
Whilst ammonia combines with acetaldehyde and its homologues,
forming aldehyde-ammonias or amido-alcohols, e.g., CH3.CH<Q^2»
when it comes into contact with formaldehyde it immediately
produces.
Hexamethylene Tetramine, Urotropin (CH2)6N4, which is known under the
name of formin, is a solvent for uric acid. It is very soluble in water, and
NITROGEN DERIVATIVES OF THE ALDEHYDES 211
crystallizes from alcohol in brilliant rhombohedra. It sublimes without decom-
position under reduced pressure. It is resolved into CH2O and ammonia when dis-
tilled with sulphuric acid. It is a monacid base, but shows no reaction with litmus
(B. 22, 1929). Efforts have been made to ascertain its molecular weight by the
analysis of its salts, by an approximate determination of its vapour density, and
by the lowering of the freezing point of its aqueous solution (B. 19, 1842 ; 21,
1570). Nitrous acid first converts hexamethylene tetramine into dinitroso-
pentamethylene tetramine, and this then into trinitrosotrimethylene triamine.
When it is considered that trimethylene trimethyl triamine is formed by the
interaction of methylamine and formaldehyde, it is obvious that the reaction
must cease at this point, because the imide-hydrogen atoms have been replaced
by methyl groups. Ammonia and formaldehyde yield at first trimethylene
triamine, corresponding with trimethylene trimethyl triamine, which absorbs
ammonia and formaldehyde, splits off water and becomes pentamethylene
diamine. The latter is converted by formaldehyde into hexamethylene tetramine.
The following constitutional formulae aim to represent this behaviour (comp.
Roscoe and Schorlemmer (1884), vol. in. 646; Duden and Scharff, A. 288, 218;
see also C. 1898, I. 36):
CH, CH,
NH
Trimethylene Triamine.
CH,
Pentamethylene Tetramine.
Hexamethylene Tetramine.
Hexamethylene tetramine forms addition compounds with bromine, iodine,
iodoalkyls and iodine, mercuric iodide and iodine, chloral and bromal (C. 1898,
II. 663 ; 1900, I. 409) :
(CH1),N4I4f (CH2)6NJ2.CH3I, (CH2)6N4I2.2HgI2, (CH2),N4.CC13CHO+2H2O.
When heated with hydrochloric or acetic acid urotropin is decomposed
respectively into formaldehyde and ammonia or into methylamine and CO2 (C. 1906,
I. 1088). Compare the formation of trimethylamine by heating formaldehyde
with ammonium salts (p. 158).
The following bodies are produced when primary amines act on formalde-
hyde (B. 28, R. 233, 381, 924 ; 29, 2110) :
Methyl Methylene Amine, [CH2=N.CH3]3, b.p. 166° ; D18.7 = 0-9215.
Ethyl Methylene Amine, [CH2=N.C2H5]3, b.p. 207°; D18.7 = 0-8923.
n-Propyl Methylene Amine, [CH2=N.C,H7]3, b.p. 248° ; D18.7 = 0-880.
The hydroiodides of methyl and ethyl methylene amines are converted by
heat into isomeric salts possessing the characteristics of quaternary ammonium
salts, as is perhaps represented by the following formulas (A. 334, 210) :
[(CH2)3(NR)3]HI and [(CH2)3(N8R2H)]RI.
By the use of aldehydes of higher molecular weight, the tendency to poly-
merization on the part of the reaction products of primary amines and aldehydes
diminishes :
Methyl Isobutylene Amine, (CH8)aCH.CH=N.CH3, b.p. 68°. Secondary amines
and formaldehyde yield —
Tetramethyl Methylene Diamine, CH2<32' b>p< 8s° (B> 26> R* 934'
B. 36, 1196).
Aldehyde bisulphites (p. 207) react with ammonia and primary or secondary
amines to form sulphurous acid esters of the aldehyde ammonias (B. 37, 4087 ; 38,
1077). They also result from the action of sodium bisulphite on alkylidine imines.
Aminomethyl Sulphurous Ester, NH2CHa.OSO2H, forms crystals soluble with
difficulty in water. Diethyl Aminomethyl Sodium Sulphite, (C2H6)2NCH2.OSO2Na,
yields tetraethyl methylene diamine when heated with hydrochloric acid or
potassium hydroxide solution. With acetic anhydride it forms Diethyl Amino-
methylene Acetate, (C2H5)2NCH?.OCOCH3, b.p.14 81°. Potassium cyanide in
aqueous solution changes it to diethyl aminoacetonitrile (C2H6)2N.CH2CN.
212 ORGANIC CHEMISTRY
Aldehyde-ammonia, CH3CH(OH)NH2, m.p. 70-80°, is produced
when dry ammonia gas is conducted into an ethereal solution of
aldehyde, and consists of brilliant rhombohedra, dissolving readily in
water. Acids resolve it into its components (p. 195) :
NH, H2S04
CHj.CHO > CH3.CH(OH)NH2 > CH3CHO+NH4H.SO4.
When kept for a long time in vacuo over sulphuric acid, the original crystals
gradually change into gleaming white ones of Ethylidenimine, (CH3CH=NH)3,
m.p. 85°, b.p. 123°. The picrate, recrystallized from alcohol, has the formula
(C2H5N)3.C8H2(N02)3OH+C2H6OH (C. 1899, I. 420).
In contact with water it passes into amorphous Hydracetamide, C6H12N2.
Sodium nitrite, added to a slightly acidified solution of aldehyde-ammonia,
produces
Nitrosoparaldimine, C6H12O2(N.NO), which by reduction becomes Amino-
paraldimine, C6H12O2(N.NH2), and this in turn, by the action of dilute sulphuric
acid, splits off Hydrazine, NH2.NH2 (B. 23, 740). Paraldimine should be viewed
as paraldehyde in which an oxygen atom has been replaced by the imino-group.
Hydrogen sulphide changes aldehyde-ammonia to Thialdine (p. 209), whilst with
hydrocyanic acid it becomes the nitrile of a-amidopropionic acid (g.v.). A rather
remarkable reaction occurs when aldehyde-ammonia acts on acetoacetic ester,
resulting in the formation of 1,3,5-Trimethyl Dihydropyridine Dicarboxylic
Ester (Vol. II.).
Hexaethylidene Tetramine, (CH3CH)6N4, m.p. 102°, with 6H2O, m.p. 96°, is
obtained by heating aldehyde-ammonia with aqueous ammonia to 150° (C. 1900,
I. 901).
•VTTT
Chloral-ammonia, CCl3CH<og2, m.p. 63°.
For the chloralimides, (CC13.CH : NH)3, and Dehydrochloralimides, CeH4Cl9N3,
consult B. 25, R. 794 ; 24, R. 628. The isomerism of the former is very probably
dependent upon the same causes as that of the polymeric thioaldehydes (p. 208).
C. Aldoximes, R'.CH=N.OH (V. Meyer, 1863).
The aldoximes are formed when hydroxylamine, in the form of
an aqueous solution of hydroxylamine hydrochloride (i mol.), mixed
with an equivalent quantity of sodium hydroxide (J mol.), acts in
the cold on aldehydes. At first there is very evidently formed an
unstable addition product, corresponding with aldehyde-ammonia,
which in the case of chloral may be obtained in stable form, but
which passes readily into the oxime :
0 NHZOH / xNH(OHK _H2o ™
CH8.C<^ ^ ( CH3CA)H ] - — ^ CH3C<^
o NH2OH /NHOH -H20
•C13C^H- .C13.C^-OH
Aldoximes can also be obtained from primary amines by oxidation wita
permonosulphuric acid, H2SO5 (B. 35, 4293). by reduction of a/J-nitroolefines
(p. 151) with zinc and acetic acid (C. 1903, II. 553) :
CH3.CH2NH2 >• CH3CH : NOH
(CH3)2C : CHN02 >• (CH3)2CH.CH : NOH
The aldoximes are colourless liquids which boil without decomposition. Th«
first members of the series dissolve readily in water. When boiled with acids they
are again changed to aldehyde and hydroxylamine. By the action of anhydrides
or acid chlorides the aldoximes are converted into nitriles :
CH3CH-NOH + (CH3CO)20=CH3C • N-f-2CH8COzH.
Acetoxime. Acetonitrile.
NITROGEN DERIVATIVES OF THE ALDEHYDES 213
The oximes and hydrazones (see below), like the aldehydes, take up hydro-
cyanic acid ; the products are amidoxyl- or hydrazino-nitriles (B. 29, 62). By the
direct action of alkyl halides on aldoximes and ketoximes only alkyl-nitrogen
/NR' yNR'
compounds of the Isoximes (Vol. II.) are formed, RHC<^ | and R2C<f I
(C. 1901, I. 1147).
Formoxiine, Formaldoxime, CH2=N.OH, b.p. 84°, passes spontaneously
into polymeric triformoxime, CH/CS'^N.OH (B. 29, R. 658).
• Formoxime yields hydrocyanic acid when it is boiled with water (B. 28, R. 233 ;
C. 1898, II. 18).
Acetaldoxime, CH3.CH:NOH, m.p. 47°, b.p. 115°, also exists in a second
modification, m.p. 12°, which readily reverts to the first form (B. 26, R. 610 ;
27, 416 ; 40, 1677 ; C. 1898, II. 178). Chlorine in hydrochloric acid solution con-
verts it into chloronitrosoethane, CH3CHC1NO (p. 153), which easily becomes
rearranged into CH8CC1 : NOH.
Chloral Hydroxylamine, CC13.CH(OH)NH(OH), m.p. 98° (B. 25, 702), even
upon standing in the air, becomes converted into
Cnloraloxime, CC13CH=NOH, m.p. 39-40°.
Propionaldoxime, C2H6.CH=N.OH, b.p. 130-132°.
Isobutyraldoxime, (CH3)2CH.CH=NOH, b.p. 139°. Isovaleraldoxime, (CH3)2-
CH.CH2.CH=NOH, b.p. 164-165°. CEnanlhaldoxime, CH3(CH2)5CH:NOH, m.p.
55-5°, b.p. 195°. Myristin Aldoxime, m.p. 82° (B. 26, 2858).
The aldoximes of the fatty series resemble the aromatic syw-aldoximes in their
behaviour (B. 28, 2019).
D. Diazoparaffins are produced, as shown by v. Pechmann in 1894, by the
action of alkalis on nitrosamines. Diazomethane alone has been carefully studied.
Diazomethane, Azimethylene, CH2N2, is best prepared by the action of
alkalis on nitrosomethyl urethane in ether solution, when the alkali methyl-azoate
is formed as an intermediate product which yields diazomethane by the action
of water (B. 35, 897) :
CH3N<^C H - > CH3N=N.OK
Diazomethane is also formed from methyl dichloramine and hydroxylamine
(p. 167) ; compare also B. 29, 961). At the ordinary temperature it is a yellow,
odourless, and very poisonous gas, which strongly attacks the skin, the eyes, and
the lungs.
Diazomethane exhibits the reactivity of diazoacetic ester (q.v.). Water con-
verts it into methyl alcohol. Iodine changes it to methylene iodide. Inorganic
and organic acids are changed into their methyl esters : hydrochloric acid into
methyl chloride ; hydrocyanic acid into acetonitrile ; phenols into anisols ;
toluidine into methyl toluidine.
Aldehydes transform it into alkyl methyl ketones (p. 217). Diazomethane
unites with acetylene to form pyrazole, and with ethylene to form pyrazoline
(C. 1905, II. 1236). With methyl fumarate it forms pyrazoline dicarboxylic ester
(B. 28, 624, 2377 ; 31, 2950). For its behaviour with quinones, compare
B. 32, 2292. On the dissociation of diazomethane into (CHa)« and nitrogen,
see B. 33, 956.
E. Aldehyde Hydrazones (E. Fischer, A. 190, 134 ; 236, 137).
The aldehyde hydrazones correspond with the aldoximes. They are
the transposition products of aldehydes and hydrazines (q.v.), which
are formed when their constituents are mixed in ethereal solution :
CH3CHO+H2N.NHC6H6 = CH3CH=N.NHC6H8+H2O.
Acetaldehyde Hydrazone, Ethylidene Phenylhydrazine, CH3.CH=NNHC,Hf,
b.p.,0 140° ; a-form, m.p. 98-101° ; jS-form, m.p. 75°, forms a white crystalline
mass which is very sensitive towards acids. When recrystallized from 75 per
214 ORGANIC CHEMISTRY
cent, alkaline alcohol the a-modification is obtained ; if it is recrystallized from
75 per cent, alcohol containing SO2 the labile ^-modification is deposited, which
gradually changes into the a-form. The two modifications are identical in struc-
ture, and are stereoisomerically connected (p. 32) (A. 342, 15). Structurally
isomeric with this compound is Phenyl Azoelhyl, C8H6N :N.CH2CH3 (Vol. II.),
which is transformed into acetaldehyde hydrazone by solution in cold concen-
trated sulphuric acid (B. 29,793). Aldehyde precipitates ^compound, CH3.CHO.-
2(C6H6NHNHa), m.p. 77*5°, from the solution of phenylhydrazine bitartrate
(B. 29, R. 596).
Propylaldehyde Phenylhydrazone, CH3.CH2.CH=N2C6H,;, b.p.180 205°. These
hydrazones take up hydrocyanic acid and pass into the nitriles of hydrazido-acids
(B. 25, 2020).
Formaldehyde differs from the higher homologues in that with phenylhydra-
zine it yields —
Trimethylene Phenylhydrazine, (CaH6N2)2(CH2)3, b.p. 183-184° (B. 29, 1473;
R. 777).
Formalaxine, (CH2=N— N=CH2)a., is a white amorphous powder insoluble
in water. Formalhydrazine, (CH, : N.NH2)8 is a water-insoluble powder,
which gives a double compound with silver nitrate (CH2:NNH2)3.2ANOg3.
It results under various conditions from formaldehyde and hydrazine hydrate
(B. 26,2360; 40,1505).
Ethylidene Azine, CHSCH : N.N : CHCH3 ; b.p. 95° (J- pr. Ch. [2] 58 325).
2B. OLEFINE ALDEHYDES, CnH^
The unsaturated aldehydes, having a double carbon bond, bear the
same relation to the olefine alcohols (p. 123) that the saturated alde-
hydes sustain to their corresponding alcohols. Their aldehyde
group shows the same reactive power as the group in the ordinary
aldehydes, but the presence of the unsaturated residue, CnH2n-i,
gives rise to addition-reactions similar to those shown by the olennes.
ajS- Olefine aldehydes result from the following special methods :
(1) By the condensation of aldehydes of the formula RCH2.CHO by zinc
chloride, hydrochloric acid, etc., during which water is split off from the aldol
first formed.
2CH3CHO - > CH3CHOH.CH2CHO - > CH3CH : CHCHO
Acetaldehyde. Aldol. Croton Aldehyde.
(2) From glycerol (see Acrolein) and from the dialkyl ethers of homologous
glycerols, by heating with anhydrous oxalic acid, accompanied by the expulsion
of water or alcohol, similarly to the formation of paraffin aldehydes from ethylene
glycol ethers (p. 192 ; A. chim. phys. [8] 9, 560)
—C2H6OH — C2H5OH
C2H5OCH2.CR.OH - > C2H6OCH2CHR — '• —> CH2=CR
CH2.OC2H6 CHO CHO
AcroleYn, CH2 : CH.CHO, b.p. 52°, D20 = 0-8410, is produced by
the oxidation of allyl alcohol and by the distillation of glycerol or fats
(i pt.) with potassium bisulphate (2pts.) (B. 20, 3388 ; A. Spl. 3, 180 ;
C. 1900, I. 962 ; B. 35, 1137), or with boric acid (B. 32, 1352 ; C.
1905, II. 302) ; and also by the decomposition of fats by heat :
CH2OH CHOH CHO CHO
CHOH -=^> CH - > CH, -=^> dH
CH2OH CH2OH CH2OH CH,
Acrolein is a colourless, mobile liquid, and has an intolerably
pungent odour. It is soluble in 2-3 parts water, and reduces an
OLEFINE ALDEHYDES 215
ammoniacal silver solution, with formation of a mirror-like deposit ;
when exposed to the air it becomes oxidized to acrylic acid. It does
not combine with primary alkali sulphites. Nascent hydrogen converts
it into allyl alcohol (p. 123).
Acrolein Acetal, CH8 : CH.CH(OC2H5)2, b.p. 123°, is formed by the action of
powdered potassium hydroxide on chloropropionaldehyde acetal, which is pre-
pared from acrolein by means of alcohol and hydrochloric acid (B. 31, 1797) (see
Glyceric aldehyde).
Phosphorus pentachloride converts acrolem into dichloropropylene, CH8 :-
CH.CHC12, b.p. 84*. With hydrochloric acid it yields ^-chloropropionaldehyde
(p. 203). With bromine it yields a dibromide, CHa.Br.CHBr.CHO, which
becomes converted into glyceric aldehyde when heated with water, and into
afi-dibromopropionic acid upon oxidation with nitric acid. Barium hydroxide
solution converts it into a-acrose or (d+1) fructose (q.v.) (B. 20, 3388).
When kept for some length of time, acrolei'n passes into an amorphous, white
mass (disacryl). On warming the HC1 compound of acrole'in (see above) with
alkalis or potassium carbonate metacrolem, m.p. 45°, is obtained. The vapour
density of this agrees with the formula (C3H<O)3.
Ammonia changes acrolein into acrolcin-ammonia, 2C3H4O+NH3=CtH,NO +
H2O. This is a yellowish mass which on drying becomes brown, and forms
amorphous salts with acids. It yields picoline, C6H4N.CH3 (</.v.), when
distilled. Hydrazine changes acrolein to pyrazoline, and phenylhydrazine
converts it into i-phenylpyrazoline (B. 28, R. 69).
Crotonaldehyde, CH3.CH : CH.CHO, b.p. 104°, D = 1-033 (Kekule,
A. 162, 91), is obtained by the condensation of acetaldehyde (p. 199)
from the primarily formed aldol by heating it with dilute hydrochloric
acid, with water and zinc chloride, or with a sodium acetate solution,
to 100° (B. 14, 514 ; 25, R. 732). When aldol is heated or treated
with dilute hydrochloric acid it loses water and becomes converted
into crotonaldehyde (p. 197 ; C. 1907, I. 1400).
Crotonaldehyde is a liquid with an irritating odour ; it becomes oxidized by the
air to crotonic acid, and it reduces silver oxide (B. 29, R. 290). It combines with
hydrochloric acid to form fi-chlorobutyraldehyde (p. 203) ; on standing with
hydrochloric acid it unites with water and becomes aldol. Iron and acetic acid
reduce it to crotonyl alcohol, butyraldehyde and butyl alcohol.
When the alcoholic solution of acetaldehy de-ammonia is heated to 120°,
Crotonal-ammonia, Oxytetraldine, CSHJ3NO, is produced. It is a brown, amor-
phous mass. When heated it breaks up into water and collidine, G6H2N(CH8),,
a pyridine derivative (Vol. II.).
Tiglic Aldehyde, Guaiol, CH8CH=C(CH,).CHO, b.p. 116°, may be obtained
by the distillation of guaiacol resin, and by the condensation of acetaldehyde and
propaldehyde.
Methyl Ethyl Acrolein, C8H5.CH:C(CH3).CHO, b.p. 137°, is produced by
the condensation of propionaldehyde (p. 201).
a-Propyl Acrolein, b.p. 117°, Isobutyl Acrolein, b.p. 133°, and Amyl
Acrolein, b.p.ls 59°, CH2:CR.CHO, are prepared from the respective glycerol
ethers (method of formation 2, p. 214).
Citronellal and its isomer Rhodinal are olefine aldehydes, and Geranlal
or Citral belongs to the class of diolefine aldehydes. These will be duly con-
sidered under the olefine terpenes (Vol. II.).
2C. Acetylene Aldehydes, CwH2n_3.CHO. Propargylie Aldehyde, CH : C.CHO,
b.p. 59*, is produced when the acetal, CH ;C.CH(OC3H5)2, b.p. 140°, formed
from dibromacroleiin acetal and alcoholic potassium hydroxide, is boiled with
dilute sulphuric acid. It is a very mobile liquid, which provokes tears. Its
silver salt is very explosive. Sodium hydroxide at the ordinary temperature
decomposes propargylic aldehyde instantly into acetylene and sodium formate :
CHi C.CHO +NaOH=CH:CH+NaO.CHO (Claisen, B. 31, 1021).
Homologous acetylene aldehydes or their vcetals are obtained from the
216 ORGANIC CHEMISTRY
sodium or magnesium haloid salts of acetylene (pp. 88, 184) by the addition of
formic or orthoformic esters (mode of formation No. o^ of the aldehydes, p. 192 ;
C. 1904, II. 187) :
RC=CNa+ HCOOC2H6 — > RC=C-CH<QH — > RCEEC.CHO.
RC=CMgI+HC(OC2H,), — > RCEEC.CH(OC2H*)2' — >• RC^C.CHO.
Amyl Propiolic Aldehyde, C6HUC^C.CHO, b.p.26 89°, Acetal, b.p.n 110°,
and Hexyl Propriolic aldehyde, C6H1SC=C.CHO, b.p.18 91°, Acetal, b.p.,a 127°,
are prepared in this way from oenanthylidene and caprylidene, respectively.
These acetylene aldehydes do not yield the anticipated oximes and hydra-
zones with hydroxylamine and hydrazine, but their internal condensation com-
pounds, such as isoxazole and pyrazole (B. 36, 3665 ; C. 1904, II. 187) :
I I NH^OH NH2NH2 I
CH:CH.CH:NO •< - CH=C.CHO - > CH:CH.CH:N.NH.
Isoxazole. Propiolic Pyrazole.
Aldehyde.
3 A. Ketones of the Saturated Series, Paraffin Ketones, CnH2nO
In the introduction to the aldehydes and ketones (p. 189) attention
was directed to the great similarity between these two classes of com-
pounds, which finds expression in their most important methods of
formation and in their transposition reactions. It was also stated
that two different kinds of ketones were known :
1. Simple ketones, containing two similar alkyl groups.
2. Mixed ketones, having two different alkyl groups.
Methods of Formation. — (i) Oxidation of secondary alcohols, whereby
the =CH.OH-group is converted into the =CO-group (p. 190).
(2) From such derivatives as oximes, hydrazones, semicarbazones, ketonic
chlorides, comparably to method 6 for the aldehydes (p. 192) :
(CH,)2CC12 — ^> [(CH,)1C.(OH)i] - > (CH3)2CO.
100"
(3) The transformation of di-primary, primary-secondary and primary-
tertiary glycols and ethylene oxides into aldehydes by means of hydrochloric
or sulphuric acids (method 7, p. 192) corresponds with the change of secondary-
tertiary and di-tertiary glycols into ketones (C. 1906, II. 670) :
(C8H6)2C(OH).CH(OH)CH, * > (C2H6)2CH.COCH,
Diethylmethyl Ethylene Glycol. Unsym.-Diethylacetone.
The change of di-tertiary glycols, known as pinacones, into ketones or pina-
colines is accompanied by the migration of an alkyl group. The simplest of
the di-tertiary glycols is Tetramethyl Qlycol, or Pinacone, from which the abstrac-
tion of water should produce tetramethyl ethylene oxide. Instead, this sub-
stance becomes rearranged internally to form the simplest pinacoline tert.-butyl
methyl ketone : —
(CH8)2C(OH) /(CHJ.Cv \
> ( I /° ) > (CH,)8C.CO.CHt;
(CH3)2C(OH) \(CH,)2C/ /
Tetramethyl Ethylene Glycol. Tert.-Butyl Methyl Ketone : Pinacoline.
(4) By action of acids (B. 29, 202) on the sodium salts of the mononitro-
paraffins (pp. 150, 151), in which the nitro-group is attached to a terminal carbon
atom:
2(CH,)2C : NOONa+2HCl=2(CH,)aCO+N80+2NaCl+H20.
(5) By hydrolysis of the ethers of ajS-olefme alcohols (p. 129) ; C. 1904, 1. 719) :
dilute
C5HnC(OCHs) : CH, > C6Hn.COCH,+CH2OH.
KETONES OF THE SATURATED SERIES 217
Nucleus-synthetic Methods of Formation. — (6) By the distillation of
calcium or barium acetates and their higher homologues. Such a
salt, when heated alone, yields a simple ketone, but a mixture of
equimolecular quantities of the salts of two acids results in the
formation of mixed ketones (p. 190).
In the formation of ketones with high molecular weight it is best to carry
out the distillation under diminished pressure. Some normal fatty acids yield
ketones on treatment with PaO6 (B. 26, R. 495).
Recently it has been recommended to distil the acids with calcium carbide
(B. 39, 1703).
(7) By the electrolysis of a mixture of the potassium salts of a keto-carboxylic
and a fatty acid :
CH3COJCO2K CH3CO
CHJCO2K CH,
CH3COCH2CHJCO2K CH3COCH2CH,
CH3jCO2K CH8
(8) By the action of the zinc alkyls on the acid chlorides
(Freund, 1860).
The reaction is similar to that occurring in the formation of the tertiary
alcohols (p. 105). At first the same intermediate product is produced (A. 175,
361 ; 188, 104) :
/,0 CH3V /OZnCH,
+Zn(CH3)2 = >C<(
CH/ \:i
which (with a second molecule of the acid chloride) afterwards yields the ketone
and zinc chloride :
CH3V /
>C< +CH3.COC1 = 2CH3.CO.CH3+ZnCl,.
CH/ XC1
In many cases, especially in the preparation of the ordinary pinacoline from
trimethyl acetyl chloride and zinc methyl, it is preferable to decompose
immediately the addition product of zinc methyl and acid chloride with water,
when the zinc hydroxide will be converted by the hydrochloric acid into zinc
chloride :
CH3V /OZnCH,
>C\ +2H2O = CH3.CO.CH3+Zn(OH)2+HCl+CH4.
CH/ XC1
(9) By the action of alkyl magnesium halides, ketones as well as aldehydes
(mode of formation 9, p. 192) can be prepared, (a) by their action on nitriles, and
(b) on acid amides (C. 1902, I. 299 ; 1903, II. mo).
(a) RCEEN+R/MgI= \C=NMgI > \C=O
R'/ R'/
Rv /OMgl Rv
(6) RCONH2+2R'MgI > >C< > >C=O
R'/ xNHMgI R'/
(10) By the action of diazomethane (p. 213), the aldehydes can be converted
into alkyl methyl ketones (B. 40, 481) :
C.H1,COH+CH,Na=C6H18CO.CH,-fNI.
218 ORGANIC CHEMISTRY
(n) By the action of anhydrous ferric chloride on the acid chlorides.
Hydrochloric acid is set free, and chlorides of ^-ketone-carboxylic acids are
produced. From these water liberates the free /J-ketone-carboxylic acids. The
latter break down readily into carbon dioxide and ketones :
CH8 CH8
Fe.Cl. • H2O • -CO4
2C1H6COC1^->C2H6CO.CH.COC1 ^C2H6CO.CH.CO2H ^C2H6CO.C2H6.
(12) Degradation Methods of Formation. — By the oxidation of dialkyl acetic
acids, and the a-hydroxydialkyl acetic acids corresponding with them ; the latter
are simultaneously formed as intermediate products in the oxidation of the former
compounds, e.g. :
o o
(CH8)2CH.C02H > (CH3)2C(OH).C02H > (CH8)2CO+CO1+H2O.
(13) By the breaking down of /?-ketone-mono- and dicarboxylic acids — e.g. :
CH8CO.CH2.C02H
Acetoacetic Acid.
COaH.CH2COCH2.C02H
Acetone Dicarboxylic Acid.
Compare acetoacetic ester, and also its homologues, such as acetone di-
carboxylic acid. Acyl acetoacetic acid breaks down in a similar way, forming
ketones, as well as carboxylic acids, with liberation of CO2 (C. 1903, I. 225) :
CH8CO.CHCOaH
RCO
The ketones are produced in the dry distillation of citric acid,
sugar, cellulose (wood), and of many other carbon compounds, so that
they are found in coal and coal-tar (B. 36, 254, 2713).
Nomenclature and Isomerism. — The term ketone is derived from
the simplest and first discovered ketone — acetone. The names of the
ketones are obtained by associating the names of the alkyls with the
word ketone — e.g. dimethyl ketone, methyl ethyl ketone, etc.
A. Baeyer regards the ketones as keto-substitution products of the hydro-
carbons, and the group CO, uniting two alkyl groups, he terms the keto-group.
As one carbon atom in the name ketopropane would, in consequence of this
suggestion, be twice designated, KekuU has suggested that the oxygen linked
doubly to carbon be called " oxo "-oxygen. Then acetone, CH8COCH8, would
be 2,-oxopropane, propionic aldehyde, CH8.CH2.CHO, would be i-oxopropane.
The " Geneva names " are obtained by adding the suffix " one " to the name[of the
hydrocarbon: acetone is called [Propanone], and methyl ethyl ketone is
[Butanone].
As there is a ketone for every secondary alcohol, the number of
isomeric ketones of definite carbon content is equal to the number of
possible secondary alcohols containing the same number of carbon
atoms. The simple ketones are isomeric with the mixed ketones having
a like carbon content. The isomerism of the ketones among them-
selves is dependent upon the homology of the alcohol radicals united
with the CO-group. (Consult the isomerism of the aldehydes (p. 193)
for the isomerism of the ketones with other compounds.)
Properties and Reactions. — The ketones are neutral bodies. The
lower members of the series are volatile, ethereal-smelling liquids,
whilst the higher members are solids.
In enumerating the reactions of the ketones, it will be best to examine
KETONES OF THE SATURATED SERIES 219
acetone, the most important and most thoroughly investigated member
of this class of bodies.
i. Ketones differ chiefly from aldehydes in their behaviour when
oxidized. They are not capable of reducing an alkaline silver solution ,
and are not so easily oxidized as the aldehydes.
When the more powerful oxidants are employed, the ketones almost
invariably break down at the union with the CO-group — carboxylic
acids are produced, and in some cases ketones with a lower carbon
content :
o
CH3.CO.CH8 > CHS.CO2H and H.CO2H > CO2+H2O
C2H5.CO.C2H5 > C2H5.C02H and CH3.CO2H.
In the case of mixed ketones, when both alcohol radicals are primary in
character, the CO-group does not, as was formerly supposed, remain exclusively
with the lower alcohol radical, but the reaction proceeds in both possible
directions, e.g. :
CH3CH2.CO.CHaCH2CH3— <^CH8.CO2H and CO2H.CH,CH4CH8
When a secondary alcohol radical is present it splits off as ketone, and is then
further oxidized, whilst with a tertiary alcohol radical the CO-group remains com-
bined as carboxyl.
The direction in which the oxidation proceeds is dependent less upon the
oxidizing agent than upon the oxidation temperature (A. 161, 285 ; 186, 257 ;
B. 15,1194; 17, R. 315; 18, 2266, R. 178; 25, R. 121).
It is remarkable that pinacoline (p. 216) is successfully oxidized by potassium
permanganate to the corresponding a-ketone-carboxylic acid of like carbon
content : trimethyl pyroracemic acid :
3O
(CH3)3C.CO.CH3 >• (CH3)3C.CO.CO2H.
Pinacoline. Trimethyl Pyroracemic Acid.
Hydrogen peroxide changes acetone into a peroxide (p. 224) which breaks
up into acetol, CH3COCH2OH, and pyroracemic acid, CH3CO.COOH (C. 1905,
II. 212).
2. Concentrated nitric acid converts the ketones in part into dinitro-paramns
(P- 154):
HN03
(C2H5)2CO > CH3CH(N02)2
(CH3CH2CH2)2CO > CH3.CH2CH(N02)2
o-Diketones may be formed at the same time if the ketone be suitably con-
stituted, e.g., isopropyl isobutyl ketone (C. 1900, II. 124).
3. Amyl nitrite, in the presence of sodium ethoxide or hydrochloric acid,
converts the ketones into isonitroso-ketones :
CBHnN02
CH3.CO.CH8 > CH3.CO.CH(NOH)
CH3CO.CH2.CH3 > CH3.CO.C(NOH).CH8.
As monoximes of a-keto-aldehydes, or a-diketones, the isonitroso-ketones will
be considered later in connection with both these classes of compounds.
4. Ketones, containing the carbonyl group next to a methyl or methylene
group, are acted on by nitrous oxide in presence of sodium ethoxide, and form
the sodium salt of di-isonitramine ketones. These are decomposed by water
into a carboxylic acid and the sodium salt of a di-isonitramine alkylene (p. 154;
A. 300, 95) :
CH3\ HNO /N2O2Na H2o ,N2O2Na
>CO > CH8CO.CH< > CH3COOH +CH2<
CH/ *C2H6orfa XN202Na NN2O2Na
5. By the action of carbon disulphide and alkali hydroxide on ketones of the
220 ORGANIC CHEMISTRY
formula RCHaCOCHaR, there are produced orange-red coloured acids, probably
of the following general formula (B. 38, 2888) : —
co<rCR=C(SH)>s
cu~
Many of the addition reactions possible with ketones are due, as in
the case of the aldehydes, to the ready destruction of the double union
between carbon and oxygen. These reactions are partly followed,
even with the ketones, by an immediate separation of water.
6. Nascent hydrogen (sodium amalgam, or electrolytic hydrogen,
C. 1900, II. 795), converts the ketones into secondary alcohols (p. 105),
from which they are produced by oxidation. Pinacones, or di tertiary
glycols, are simultaneously formed (p. 216) :
fCH ) COH
(CH,)8CO+ 2H = (CH8)aCH.OH ;
7. The ordinary ketones, like the ordinary aldehydes, do not combine with
water, but when containing numerous halogen atoms, they unite with 4HaO and
2HaO, forming hydrates.
8. The ketone derivatives, corresponding with the acetals (p. 205), are produced
when the j8-dialkoxycarboxylic acids, RC(OCaH5)2CH2CO2H, lose CO2, and
by the interaction of ketones and orthoformic ester ; or in general from imido-
ether hydrochlorides and alcohols (Claisen, B. 31, 1010 ; B. 40, 3021).
9. The ketones resemble the aldehydes in their behaviour —
a. with hydrogen sulphide ;
b. with mercaptans in the presence of hydrochloric acid.
The products are polymeric thioketones (p. 225), and the mercaptols, e.g.,
(CH3)2.C(SC2H6)2, corresponding with the mercaptals (p. 209).
10. The ketones, unlike the aldehydes, do not combine with the acid anhy-
drides.
ii. Only those ketones, which contain a methyl group, form
crystalline compounds with the alkali bisulphites. These, like the
corresponding aldehyde compounds, can be considered as salts of
sulphurous acid esters :
These double salts are very suitable for the isolation and puri-
fication of the ketones, which can be liberated from them by dilute
sulphuric acid or a sodium hydroxide solution.
12. Behaviour of ketones with ammonia, hydroxylamine and phenyl-
hydrazine. (a) Acetone behaves differently towards ammonia from the
aldehydes. Nucleus-synthetic reactions occur, with the formation of
diacetonamine and triacetonamine (p. 230). Homologous ketones,
however, react with ammonia according to the equation (C. 1905,
II. 540; 1907, I. 810):
3R2CO+2NH,=(R,C=N)aCRa+3HaO.
With hydroxylamine, however, the ketones, like the aldehydes
(p. 196), yield (b) ketoximes (p. 227), (c) with phenylhydrazine they
form hydrazones (p. 228), and (d) with semicarbazide they give
semicarbazones (p. 228).
13. When phosphorus trichloride acts on acetone in the presence of
A12C16, hydrochloric acid is set free, and there results the compound
PCI— o
(B. 17, 1273; 18, 898).
KETONES OF THE SATURATED SERIES 221
14. Phosphorus peniachloride, phosphorus trichloro-dibromide, and
phosphorus pentabromide replace the oxygen of the ketones by two
chlorine or two bromine atoms.
This reaction can be employed for the preparation of dichloro- or dibromo-
paraffins in which an intermediate C-atom carries the two halogen atoms. As
these ketone chlorides readily exchange their chlorine for hydrogen, they constitute
a means of converting the ketones into the corresponding* paraffins (p. 74).
15. The hydrogen atoms of the alkyl groups present in the ketones can be
replaced by chlorine and bromine.
1 6. Boiling with acid chlorides, especially benzoyl chloride, converts many
ketones into esters of the isomeric ajS-olefine alcohols (p. 124), RC(O.COC,H6) :
CHR'.
17. Unlike the lower members of the aldehyde series which easily
undergo polymerization, the ketones never do this. Compared with
aldehydes the ketones possess a symmetrical structure.
Nucleus-synthetic Reactions of the Ketones. — Reactions of this class were ob-
served in the action of ammonia and of phosphorus trichloride on acetone
in the presence of aluminium chloride (comp. 12 and 13). The following are,
however, more important : —
(i) Just as two aldehyde molecules condense to aldol, so aldehyde or chloral
will unite with acetone, forming hydracetyl acetone and trichlorohydracetyl acetone
(q.v.):
Acetone will also condense with other aldehydes, — e.g., benzaldehyde. But
it is impossible to obtain the ketone-alcohols which form at first. There is a loss
of water, and unsaturated derivatives are produced, just as in the condensation of
two molecules of aldehyde to form crotonaldehyde. Thus, two molecules of acetone,
in the presence of ZnCl2,HCl, or H2SO4, unite directly, with the elimination of
water, to form mesityl oxide (p. 229), which in turn condenses with a third
molecule of acetone to form phorone (p. 229).
(CH,),CO+CH8.CO.CH, = ™8>C=CH.CO.CH8-f-H8O.
3 Mesityl Oxide.
/"*TJT «. f*TT ^
V^ri8\/-« r'TT f^f\ r"C-f j_PO^r*W A — 3 >r* PTT PO PTT —
~uV^^=^W.lAJ.Lx±l3-f-L/<JK^.rl3Jj = /-TT x^v/ — ^ll.vAJ.^Jtl =
CH8 «-xis
Phorone.
(2) Acetone and other ketones, having a suitable constitution, change
into symmetrical trialkyl benzenes, under the influence of concentrated
sulphuric acid. It is very probable that there is an intermediate
formation of alkylated acetylenes (p. 89). Acetone yields mesitylene :
CH8 CH3 /CH8
H2so4 / • \ /ci^ar
3CO > he ) > CH3.C^ ^CH
CHS CH \:H,
Acetone. Allylene. Mesitylene.
(3) Acetone condenses, in presence of lime or sodium ethylate, to
isophorone, a trimethyl cyclo-hexenone (q.v.).
A sodium hydroxide solution at o° causes two molecules of acetone to condense
to diacetone alcohol, (CH3)2C(OH).CH2COCH3.
(4) The ketones, like the aldehydes, unite with hydrocyanic acid to form
hydroxycyanides or cyanhydrins, the nitriles of the a-hydroxy-acids. They will
222 ORGANIC CHEMISTRY
be described after the a-hydroxy-acids, into which they pass when treated with
hydrochloric acid :
HNC /-N HC1 ro H
(CH3)aCO -- > (CH,)aC<^ 2HaQ > (CH8)a.C<CQ*H
a-Hydroxyisobutyric Acid.
(5) Acetone, in the presence of sodium hydroxide, combines with chloroform,
yielding acetone chloroform, which is a derivative of a-hydroxyisobutyric acid;
the latter can be obtain^ from it :
(CHJ.CO CHC* > (CH3)2C<gj^ - > (CH3)2C<£°*H
Acetone Chloroform. a-Hydroxyisobutyric Acid.
(6) Nascent hydrogen converts the ketones not only into secondary alcohols
(p. 1 06), but also into pinacones, or di-tertiary glycols (p. 220) :
Acetone, Dimethyl Ketone [Propanone], CH3.CO.CH3, m.p. —94°
(B. 33, 638), b.p. 56*5°, D20 = 07920, is isomeric with propion-
aldehyde, propylene oxide, trimethylene oxide, and allyl alcohol. It occurs
in small quantities in the blood and normal urine, whilst in the urine of
those suffering from diabetes it is present in considerable amount, due,
apparently, to the breaking down of the acetoacetic acid formed at
first. It is also produced in the dry distillation of tartaric acid, citric
acid (q.v.), sugar, cellulose (wood), and is, therefore, found in crude
wood spirit (p. 109). Technically it is prepared by the distillation of
calcium acetate, or from crude wood spirit.
It is also formed : by the oxidation of isopropyl alcohol, isobutyric acid, and
a-hydroxyisobutyric acid ; by heating chloracetol and bromacetol, CH3CBr2CH3,
with water to 160-180° ; and j3-chloro- and jS-bromopropylene, CH3CBr=CH2,
with water at 200°.
It would naturally be expected that an alcohol, CH3.C(OH) : CH2, would be
formed, but a transposition of atoms occurs and acetone results (see p. 36).
Acetone is similarly formed from allylene, CHS.C • CH, by action of sulphuric acid
or HgBra in the presence of water (p. 89).
It results, further, in the action of zinc methyl on acetyl chloride ; and,
accompanied by diacetyl, by the electrolysis of a solution of pyroracemic acid and
potassium acetate (B. 33, 650. Acetone is also formed from a-bromoisobutyric
amide by bromine and alkali (C. 1905, I. 1219) :
2KOH
(CH8)aCBr.CONHBr - > (CH3)2CO+NH8+2KBr-f-CO,.
(See also the general methods of formation of the ketones, pp. 216, 217.)
Acetone is a mobile, peculiar-smelling liquid, and is miscible with
water, alcohol, and ether. Calcium chloride, or potassium carbonate,
throws it out from its aqueous solution.
It is an excellent solvent for many carbon compounds, and for many
inorganic salts such as potassium permanganate, etc. (B. 37, 4328). Its
most important reactions were described under the reactions of
the ketones (p. 218), as well as its behaviour towards nascent hydrogen,
oxidizing agents, amyl nitrite, hydrogen sulphide, mercaptans and
hydrochloric acid, alkali bisulphites, ammonia, hydroxylamine, phenyl-
hydrazine, phosphorus pentachloride, halogens, condensation agents,
hydrocyanic acid, chloroform, and potassium hydroxide. (See j5- Allyl
Alcohol, p. 124, for the action of sodium on acetone.)
Acetone is used in the preparation of sulphonal (p. 226), chloroform
(P- 245)» and iodoform (p. 246) ; the production of the latter serves for
its detection (B. 13, 1002 ; 14, 1948 ; 17, R. 503 ; 29, R. 1006). (For
KETONES OF THE SATURATED SERIES
223
other such reactions, consult B. 17, R. 503 ; 18, R. 195 ; A. 223, 143.)
Acetone can be quantitatively determined by means of mercuric
sulphate (B. 32, 986) ; also by heating it with mercuric acetate, whereby
acetone-mercury substitution compounds are produced (B. 36, 3699).
Mercuric oxide dissolves in a weakly alkaline aqueous solution of
acetone, forming ^the compound 2C3H6O.3HgO which by boiling with
alkalis changes to the insoluble Acetone Mcrcarbide, CH3COCHg3O2H
(B. 38, 2677).
Homologucs of Acetone. — (a) Simple Ketones are usually prepared by the dis-
tillation of the calcium or barium salts of the corresponding fatty acids.
Name.
Formula.
M. P.
B. P.
Diethyl Ketone, Propione [3-Pentanone]
Di-n-Propyl Ketone, Butyrone .
Di-isopropyl Ketone, Tetramethyl Ace-
tone ....
CO(C2H6)a
CO(C3H7)3
COfCHfCHJo'L
-
103°
M4°
I2A°
Di-isobutyl Ketone, Isovalerone
n-Caprone ....
CO[CH2CH(CH3)2]2
CO(CKH,,U
I4'6°
*•*•'*
I65°
226°
Tetraethyl Acetone
COrCHfCoH*),!,
2O3°
CCHC.H,,),
30°
26^°
COfC.H..),
40°
CO(C.H,,)»
48°
COfCiiH,,)*
69°
Myristone
Palmitone . . .
CO(C13H27)a
CO(C,rHo.U
76°
Sq°
.—
Stearone
CO(C,,H,K),
88°
Diethyl Ketone is produced from carbon monoxide and potassium ethyl (p. 184).
Tetramethyl and Tetraethyl Acetone have been obtained as decomposition
products of pentamethyl and pentaethyl phloroglucinol, when these bodies were
oxidized by air (B. 25, R. 504).
(b) Mixed Ketones. Most of the members of this class are made by the
distillation of the barium salts of the corresponding fatty acids with barium
acetate (p. 217).
Name.
Formula.
M. P.
B.P.
Methyl Ethyl Ketone [Butanone] . .
Methyl Propyl Ketone [2-Pentanone] .
Methyl Isopropyl Ketone [Methyl Buta-
none]
CH3.CO.C2H5
CH3.CO.C8H7
CH3.CO.CH(CH3)2
81°
102°
06°
Methyl sec. -Butyl Ketone ....
Pinacoline, Methyl tert.-Butyl Ketone
Methyl CEnanthone Methyl Hexyl Ke-
CH3.CO.CH2CH(CH3)2
CH8.CO.C(CH3)3
CH3.CO.C6H13
—
116°
1 06°
171°
Methyl Heptyl Ketone .....
Methyl Nonyl Ketone
CH3.CO.C7H15
CH3.CO.CBHin
-15°
4-is°
193°
22*°
Methyl Decyl Ketone ....
CH,.CO.CinH21
«\°
247°
Methyl Undecyl Ketone from Laurie
Acid
CH3.CO.CnH28
28°
263°
Methyl Dodecvl Ketone
CH3.CO.C12H2.
34°
(207°)
Methyl Tridecyl Ketone from Mvristic
Acid
CHo.CO.QiH.,
09°
(224°)
Methyl Tetradecvl Ketone ....
Methyl Pentadecyl Ketone from Pal-
mitic Acid
CH3.CO.C14H2t
CH3.CO.C15H3,
43°
48°
(231°)
(244°)
Methyl Hexadecyl Ketone from Mar-
garic Acid ....
CH,.CO.C1(1H,o
52°
(2*2°)
Methyl Heptadecyl Ketone from Stearic
Acid .
CHa.CO.C^H™
^°
(26*°)
224 ORGANIC CHEMISTRY
The boiling points, inclosed in parentheses, were determined under 100 mm.
Methyl Ethyl Ketone occurs in crude wood spirit. Methyl sec.-Butyl Ketone
results from the interaction of methyl-acrylic ester, CH2:C(CH3).CO2R, with two
molecules of magnesium methyl iodide (C. 1907, I. 559). Methyl Hexyl Ketone
is obtained from cenanthol and diazomethane (mode of formation 13, p. 218).
I Pinacoline is obtained by the withdrawal of water from the pinacone,
tetramethyl ethylene glycol,' (CH3)2C(OH).C(OH)(CH3)2, and from trimethyl
acetyl chloride and zinc methyl (p. 217). When oxidized with chromic acid, it
breaks down into trimethyl acetic and formic acid. Potassium permanganate
converts it into trimethyl pyroracemic acid (q.v.). It is converted by
iodomethane and alkali Into Pentamethyl Acetone (CH,)3C.COCH(CH3)2, b.p.
134° (A. 310, 325). Reduction produces pinacolyl alcohol (p. 122). For further
changes, see C. 1906, II. 496. Homologous pinacones yield homologous
pinacolines; thus Methyl Ethyl Pinacone, £>C(OH).C(OH)<* , yields Ethyl
(CH3)2x
tert.-Amyl Ketone, ^>C.CO.CaH5, b.p. 150°.
C2H6
Methyl Nonyl Ketone is the chief constituent of oil of rue (from Ruta grave-
olens), from which it may be extracted by shaking with concentrated sodium
bisulphite solution (C. 1902, I. 744). Methyl Heptyl Ketone occurs in the
same oil (C. 1901, I. 1006 ; 1903, I. 29 ; B. 35, 3587).
Aeetone Peroxide. Two cyclic acetone peroxides are known. Cyclo-diacetone
Peroxide (CH3)2C<Q~Q>C(CH3)2, m.p. 132°, is prepared by the action of H2SO6
(Caro'sacid) on acetone (B. 33, 858). Cyclo-triacetone Peroxide (C3H6O2)3, m.p. 97°,
is obtained from acetone and hydrogen peroxide, with special ease when in the
presence of hydrochloric acid. It is insoluble in water, but soluble in benzene
and in ether. It forms beautiful crystals, and explodes when struck or suddenly
heated (B. 28, 2265). Methyl ethyl ketone and H2SO5 produce Methyl Ethyl
Ketone Peroxide (C4H,O2)2, a colourless oil, which explodes above 100° (C. 1907, I.
944).
I. HALOGEN SUBSTITUTION PRODUCTS OF THE KETONES, PARTICU-
LARLY ACETONE
Monochloracetone, CH3.CQ.CH2C1, b.p. 119°, is obtained when chlorine is
conducted into cold acetone (A. 279, 313), preferably in the presence of marble
(B. 26, 597) ; also by the electrolysis of a mixture of acetone and hydrochloric
acid (C. 1902, I. 101). Its vapours provoke tears.
a-Dichlpracetone, CH3.CO.CHCla, b.p. 120°, is formed on treating warmed
acetone with chlorine, and is also obtained from dichloraceto-acetic ester
(B. 15, 1165). /J-DIchloracetone, C1CH2.CO.CH2C1, m.p. 45°, b.p. 172-174°,
is obtained by the chlorination of acetone and in the oxidation of a-dichlorhydrin,
CH2C1.CH(OH).CH8C1 (q.v.), with potassium dichromate and sulphuric acid.
sym.-Tetrachloracetone, CHC12.CO.CHC12+2H2O, m.p. 48-49°, is obtained
by the action of potassium chlorate and hydrochloric acid on chloranilic acid
(B. 21, 318) and triamidophenol (B. 22, R. 666); or of chlorine on phloro-
glucinol (B. 22; 1478). unsym.-Tetrachloracetone, CH2C1.CO.CC12, b.p. 183°,
is produced by the action of chlorine on isopropyl alcohol (C. 1897, I. 28).
Pentachlor acetone, CHCla.CO.CCl3, b.p. 193°, is obtained from chlorine and
acetone (A. 279, 317).
Monobromacetone, CH2Br.CO.CH3, b.p.8 31° (B. 29, 1555 ; 31, 2684). Penta-
bromacetone, m.p. 74°, is produced from acetone dicarboxylic acid and bromine
(C. 1899, I. 596). Perbromacetone, CBra.CO.CBr3, m.p. 110-111°, is obtained
from triamidophenol (B. 10, 1147), and bromanilic acid (B. 20, 2040 ; 21, 2441)
by means of bromine and water.
lodoacetone, CH3.CO.CH2I, b.p.j, 58°, is produced when potassium iodide
in an aqueous methyl alcohol solution acts on monochloracetone (B. 29, 1557).
It is a heavy oil with an intolerable pungent odour.
SULPHUR DERIVATIVES OF THE SATURATED KETONES 225
jS-Di-Iodoacetone, CH2I.CO.CH2I, results when iodine chloride acts on
acetone.
fi-Chlorisobutyl Methyl Ketone, (CH3)2.CC1.CH2.CO.CHS, and Di-fi-chloriso-
butyl Ketone, (CH3)2CC1.CH2.CO.CH2CC1(CH3)2, are the readily decomposable
addition products of mesityl oxide and phorone with hydrochloric acid. w-Bromo-
butyl Methyl Ketone, see Acetobutyl Alcohol.
y-Dibromoketones are prepared from the oxetones (q.v.) by the addition of
2HBr, e.g. y-Dibromobuiyl Ketone, (CH8CHBr.CH2.CH2)2CO, is formed from
dimethyl oxetone and 2HBr, or by the addition of 2HBr to diallyl acetone (p. 232)
a-Dichloroketones are discussed with the diketones.
2. ALKYL ETHERS OF THE ORTHO-KETONES
The ketones may be regarded as the anhydrides of hypothetical glycols, which
bear the same relation to the ketones that the orthocarboxylic acids do to the
carboxylic acids. In this sense it is then permissible to speak of ortho-ketones.
Their alkyl ethers, corresponding with the acetals, are produced by heating the
jS-diethoxy-carboxylic acids, and also from acetone by means of orthoformic
ester (Claisen, B. 31, 1010) :
CH3.C(OC2H5)2CH2.C02H - > CH3.C(OC2H5)2.CH3+CO2
CH3.CO.CH3+HC(OC2H6)3 - > CH3.C(OC2H6)2CH3+HCO2C2H..
Orthoacetone Methyl Ether, (CH3)2C(OCH3)2, b.p. 83°. Orthoacetone Ethyl
Ether, b.p. 114°, is a liquid with an odour resembling that of camphor. These
substances are stable when pure, but water or a trace of mineral acid causes them
to break down into ketones and alcohols.
The ortho-ester homologues of orthoformic esters react on ketones like the
first member, and the same may be said of the imido-ether hydrochloride and
alcohol mixture. Methyl Ethyl Ketone Orthoethyl Ether, b.p. 120° ; Diethyl
Ketone Orthoethyl Ether, b.p. 154° ; Dipropyl Ketone Orthoethyl Ether, b.p.12 70°,
are prepared from acetimido-ether hydrochloride or phenyl acetimi do-ether
hydrochloride and alcohol (B. 40, 3020).
3. KETONE HALIDES
are produced, as mentioned on p. 220, by the action of PC15, PCl3Br2, and PBr8
upon ketones. They easily give up the halogen in form of acid, forming halogen
defines (p. 96), which in turn yield acetylene, by the action of alkalis (p. 96).
Acetone Chloride, Chloracetol, CH3.CC12.CH3, b.p. 70°; D16=i-827. Brom-
acetol, b.p. 114°; D0=i'8i49.| Methyl Ethyl Dichloromethane, CH3.CC1?.C2H5,
b.p. 96°. Methyl Ethyl Dibromomethane, b.p. 144°. Methyl tert.-Butyl Dichloro-
methane, CH3.CC12.C(CH3)3, is produced from pinacoline by PC16 (comp. C. 1906,
II. 496). Heptachloropropane, CHC12.CC12.CC13, m.p. 30°, b.p. 150°, is obtained
from pentachloracetone (A. 297, 314).
4. KETONE BISULPHITES AND SULPHOXYLATES
The addition compounds, which many ketones form with alkali bisulphites,
comparably with the aldehydes (p. 207), are probably salts of acid sulphurous
esters with ortho-ketones :
^r/ 3Nr^
CH3>C<OS02Na C2H5>C<-OS02Na
With alkali cyanides they yield hydroxy-acid nitriles (C. 1903, I. 1244). Reduc-
tion produces ketone sulphoxylates , (CH3)2C(OH).OSONa, which are also formed,
together with bisulphites, from ketones and hydrosulphites (C. 1907, I. 855).
5. SULPHUR DERIVATIVES OF THE SATURATED KETONES
A. Thioketones and their Sulphones.— When hydrogen sulphide acts on
a cold mixture of acetone and concentrated hydrochloric acid, the first product
VOL. I. Q
Trithioaeetone,
226 ORGANIC CHEMISTRY
is a volatile body with an exceedingly disagreeable odour which spreads with
great rapidity. It is probably thioacetone, which has not been further in-
vestigated. The final product of the reaction is —
s— rC(CH3)2
, (CH3)2C< S< , m.p. 24°, b.p.18 130°. Potassium
\S—\C(CH8)a
permanganate oxidizes it to —
Trisulphone Acetone, [(CH3)aCSOa]3, m.p. 302°. When distilled at the
ordinary pressure it is converted into
Dithioacetone, (CH8)aC<J>C(CH8)2, b.p. 183-185°. This is also formed
in the action of phosphorus trisulphide on acetone. It is converted, by oxida-
tion, into —
Disulphone Acetone, [(CH8)aCS9a]a, m.p. 220-225°.
Methyl ethyl ketone behaves similarly (C. 1903, II. 281).
B. Mercaptols and their Sulphones. — Although the ketone derivatives corre-
sponding with the acetals cannot be derived from ketones and alcohols by the
withdrawal of water, it is possible to obtain the mercaptols — the ketone derivatives
corresponding with the mercaptals — in this manner ; but best, however, by the
action of hydrochloric acid on ketones and mercaptans :
HCl
(CH8)aCO+2CaH5SH - > (CH,)2C(SC2H8)1+H20.
Like the mercaptals, they are liquids with unpleasant odour.
Acetone Ethyl Mereaptol, Dithioethyl Dimethyl Methane, (CH8)2C(SC2H6)2,
b.p. 190-191°, may be prepared from mercaptan. However, to avoid the
intolerable odour of the latter, sodium ethyl thiosulphate and hydrochloric acid
are used (p. 147). It combines with methyl iodide (B. 19, 1787 ; 22, 2592). By
this means, from a series of simple and mixed ketones, corresponding mercaptols
have been made, and in nearly all instances they have been oxidized to the
corresponding sulphones, some of which possess medicinal value.
Sulphonal, Acetone Diethyl Sulphone, (CH5)2C(SO2C2H5)2, m.p. 126°, was
discovered by Baumann, and was introduced into medicine, as a very active
sleep-producing agent, by Kast in 1888. It is prepared by oxidation of acetone
mercaptol with potassium permanganate :
4O
(CH8)a.C(SCaH8)2 - > (CH8)a.C(SOaC2H6)a.
Sodium hydroxide and methyl iodide (A. 253, 147) acting on ethylidene
diethyl sulphone (p. 210) produce 'it:
NaOH CH3I
CH8CH(S03CaH6)a - MJH,.CNa(SOiCtH.)1 -- ^(CH3)2C(SO2C2H5)2.
Trlonal, Methyl Ethyl Ketone Diethyl Sulphone, Diethyl Sulphone Methyl Ethyl
Methane, C^3>C(SO2C2H6)2, m.p. 75° ; Tetronal, Pentane-yy-diethyl Sulphone,
(CaH5)2C(S02C2H6)2,m.p.85°; Pentane-yy-dimethylSulphone,(C2H6)2C(SO2CH3)a,
m.p. 132-133°, and other " sulphonals," are prepared similarly to sulphonal, and
act in like manner. However, Acetone Dimethyl Sulphone, (CH8)aC(SOaCH8)2,
not containing an ethyl group, no longer acts like sulphonal.
6. NITROGEN DERIVATIVES OF THE KETONES
A. Nitre-compounds. — Pseudonitroles (p. 153) and Mesodinitroparaffins (p. 154)
have already been discussed after the mononitroparamns.
B. Ammonia and ketones. — Two bases result from the action of ammonia
on acetone: diacetonamine and triaeetonamine (p. 230). From methyl-
ethyl ketone, diethyl ketone, and methyl propyl ketone, ammonia produces oils
of the formula R2C(N:CRa)a, from which the original ketone is easily recovered
(C. 1905, II. 540 ; 1907, I. 810).
O. Hydroxylamlne and ketones.
NITROGEN DERIVATIVES OF THE KETONES 227
Ketoximes (V. Meyer). — In general, the ketoximes are formed
with greater difficulty than the aldoximes (B. 39, 1452). It is usually
best to apply the hydroxylamine in a strongly alkaline solution (B. 22,
605 ; A. 241, 187). They are also produced when the pseudonitroles
are reduced by free hydroxylamine or potassium hydrosulphide (B.
28, 1367 ; 29, 87, 98). They are very similar in properties to the
aldoximes. Acids resolve them into their components, whilst sodium
amalgam and acetic acid convert them into primary amines (p. 158).
They are characteristically distinguished from the aldoximes by their
behaviour towards acid chlorides or acetic anhydride, yielding in part
acid esters ; and by their conversion by the same reagents, as well as
by HC1 or H2SO4 in glacial acetic acid, into acid amides (Beckmann's
inversion, B. 20, 506, 2580; comp. also B. 24,4018; A. 312, 172, note).
CH3CO.NHCH2CH.CH8.
CH CH CH 3.2.
Methyl Propyl Ketoxime. Acetopropylamide.
If the two alkyl groups in a ketone differ only slightly from one another,
two isomeric amides are formed. If one alkyl group contains many more carbon
atoms than the other, it is usually the group richer in carbon that wanders to
the nitrogen atom (C. 1904, I. 355). For the investigation of this change, which
is comparable to that undergone by carboxylic bromamides, azides, and hydrox-
amic acids (p. 244), see C. I9°3» I. 489-
Nitrogen tctroxide converts the ketoximes into pseudonitroles (p. 153).
Chlorine and sodium hydroxide or bromine and pyridine produce i,i-chloro- and
bromo-nitrosoparaffins (p. 153).
Ketoximes combine with hydrocyanic acid to form nitriles of a-amidoxyl
carboxylic acids (B. 29, 62).
Acetoxime, (CH3)2C:NOH, m.p. 59-6o°, b.p. 135°, smells like chloral.
It dissolves readily in water, alcohol, and ether, from which it crystallizes well
(B. 20, 1505 ; 39, 876).
The hydroxyl hydrogen present in acetoxime may be replaced by acid radicals
through the agency of acid chlorides or anydrides (B. 24, 3537).
Methyl Ethyl Ketoxime, b.p. 152-153°. Methyl n-Propyl Ketoxime, b.p. 168°
(C. 1898, II. 474), is an oil with an agreeable odour. Methyl Isopropyl Ketoxime,
b.p. 157°. Methyl n-Butyl Ketoxime, b.p. 185°. Methyl tert.-Butyl Ketoxime,
Pinacoline Oxime, m.p. 75°, reacting with PC16 produces aceto-tert.-butyl-
amine. Nitrogen tetroxide does not produce pseudonitroles, but a nitrimine,
C(CH3)3.C(CH3):N.NO2, or the desmotrope C(CH3)3C(:CH2).N:NOOH. (Comp.
mesityl nitrimine, p. 231, and A. 338, I.) n-Butyrone Oxime, b.p. 193°.
Isobutyrone Oxime, m.p. 6-8°, b.p. 181-185°. Methyl Nonyl Ketoxime, m.p. 42°,
behaves contrary to the rule (see above) and undergoes internal change under
the influence of concentrated sulphuric acid, forming considerable quantities
of capric methylamide, C9H19CONHCH3, together with acetononylamine (B. 35,
3592). Capryl Ketoxime, m.p. 20°. Nonyl Ketoxime, m.p. 12°. Lauryl Ketoxime,
(CuHM)aC:N.OH, m.p. 39° Myristyl Ketoxime, (C13 Ha7C:N.OH, m.p. 51°. Pal-
mityl Ketoxime, (C15H12)2C:N.OH, m.p. 59°. Steary I Ketoxime, (C17Ha6)2C:N.OH,
m.p. 62°.
When a solution of a ketoxime is acted on by iodo-alkyls in the presence of
sodium methoxide, a mixture is formed, which on distillation yields alkylated
oximes such as (CH3)2C:NOCH«. These pass over, and alkylated isoketoximes
(CH,)2C— NCH3.NaI
remain behind combined with Nal as \/ . The alkyl iso-
O
ketoxime cannot be obtained from this compound.
Acetoxime Ethyl Ether, (CH3)2C=NOCH3, b.p. 72°. Methyl Isoacetoxime
(CH3)2C— N.CH3.NaI
Sodium Iodide, \/ , m.p. 206°, with decomposition, and others
of this group, see C. 1901, II. 184.
228 ORGANIC CHEMISTRY
D. Ketazlnes (Curtius and Thun).—An excess of hydrazine acting on the
ketones produces the unstable, secondary symmetric hydrazines, readily changing
even in the cold into ketazines, which are quite stable towards alkalis (B. 25,
R. 80). Dimethyl ketazine in contact with maleic acid changes into the
isorneric trimethyl pyrazoline {B. 27, 770; C. 1901, II. 1121):
(CH3)aC=N N=CCH,
(CH3)SC=N ~ HN CH,
C(CHS)8.
The homologues of methyl-alkyl ketazine behave similarly, whilst diethyl
ketazine dees not undergo the change (C. 1898, II. 1249).
Bis-dimethyl Azimethylene, Dimethyl Ketazine, [(CH,)2C:N]2, b.p. 131°;
Bis-methyl Ethyl Azimeththylene, b.p. 170°; Bis-methyl Propyl Azimethylene, b.p.
197°; Bis-methyl Hexyl Azimethylene, b.p. 290°; Bis-diethyl Azimethylene,
b.p. 193°.
E. Ketone Phenylhydrazones (E. Fischer, B. 16, 66 1 ; 17, 576 ; 20, 513 ;
21, 984). — These compounds result by the action of phenylhydrazine on the
ketones. The phenylhydrazine is added to the ketone until a sample of the
mixture no longer reduces an alkaline copper solution. They behave like
the aldehyde phenylhydrazones (p. 213).
Acetone Phenylhydrazone, (CHa)2C:N2HC6H6, m.p. 16°, b.p.93 165°.
Methyl n-Propyl Ketone Phenylhydrazone, b.p.100 206°.
p-Nitrophenylhydrazones are specially suitable for identifying ketones on
account of the relative insolubility of the compound formed. Acetone p-Nitro-
phenylhydrazone, (CH3)2C:NNHC6H4NO2, m.p. 148° (C. 1904, I. 14).
Ketone Semicarbazones result when ketones are mixed with
semicarbazide, NH2CO.NH.NH2 (q.v.) at ordinary temperatures.
Such compounds are particularly suitable for the identification of the
ketones, on account of the excellent way they crystallize. Acetone
Semicarbazone, (CH3)2C:NNHCONH2, m.p. 187°. Ethyl Methyl
Ketone Semicarbazone, m.p. 135°. Diethyl Ketone Semicarbazone,
m.p. 139°, and other members, see B. 34, 2123.
3B. Olefine and Diolefine Ketones.
Olefme ketones, in which the double bond is situated next to the keto-group,
are very easily prepared, and are interesting in their behaviour.
(1) (a) ajS-olefine ketones are obtained from the product of condensation of
ketones with aldehydes or ketones ; the i,3-keto-alcohols which are formed
easily give up water :
CH3CHO+CH3COCH3 > CH3CH(OH)CHaCOCH8 > CH3CH:CHCOCH3.
Condensation of several molecules of the same ketone results in the formation
of ajS-olefme ketones and a2J32-diolenne ketones : acetone yields Mesityl Oxide
and Phorone :
(CH3)2CO
2CH3COCH3 >• (CH3)2C:CHCOCH3 > (CH3)2C:CHCOCH3C(CH3)2.
(6) The haloid esters of the i,3-keto-alcohols, such as j8-chloro- and ^3-bromo-
ketones, easily give up halogen acids, forming ajS-olefine ketones ; e.g. jS-chloro-
ketones (prepared from j8-chloropropionyl chloride and zinc alkyls : mode of
formation, p. 217), and diethyl aniline yield vinyl alkyl ketones (C. 1906, 1. 650) :
Zn(C4H5)2
C1CH2CH2COC1 > C1CH2CH2COC2H5 > CH2:CHCOC2H5.
(c) Allyl alkyl ketones, which can be prepared from the acid nitriles, allyl
iodide and zinc (comp. mode of formation 9, p. 217) very easily change into
propenyl a'lryl ketones, under the influence of mineral acids (C. 1905, I. 431):
C3H6ZnI
CH.CjN > CH9COCH2CH:CH2 > CH3COCH:CHCH3.
(2) defines with any desired position of the double bond can be obtained
OLEFINE AND DIOLEFINE KETONES 229
by decomposing olefine-substituted j8-ketone acid esters or jS-diketones (comp.
mode of formation 13, p. 218) ; e.g. allyl acetic ester gives allyl acetone ; dimethyl
allyl acetyl acetone yields dimethyl heptenone.
The aJ3-olefine ketones are remarkable for the great additive capacity of their
C=C group, which approximates to that of the C=O group. Hydroxylamine
produces not only oximes but also fi-Hydroxylamino-oximes, RCH(NHOH).-
CH2C(:NOH)R. Ammonia, primary and secondary amines are particularly
easily taken up, forming fi-aminoketones. Hydrazines react with the CO and
C =C groups, producing cyclic pyrazolines. Mercaptans form not only mercaptols,
but also mercapto-mercaptols, even when the C=C group is not contiguous to
the CO group ; e.g.
CH3CH(SC2H5)CH2C(SC2H6)2CH3, CH3CH(SCaH5)CH2CH2C(SC2H6)aCH3,
etc. In phorone, only the two C=C groups react :
(CH3)2C(SC2H5).CH2.CO.CH2C(SC2H5)(CH3)2 (B. 37, 502).
Sulphurous and hydrocyanic acids sometimes unite with the C = C group
rather than with the CO. Malonic ester, acetoacetic ester, and other such
reactive bodies similarly unite with the C=C bond of ajS-olefine ketones, forming
RCOCH2CR.CH(C02C2H6)2, etc. •
Addition compounds with the halogen acids are very readily formed.
It is a general rule that, when HX becomes attached to these unsaturated
substances, the hydrogen atom always takes the a- position to the CO group, and the
X group the ^-position.
Bromine forms a/?-dibromoparafrins, which readily give up HBr, leaving
a-bromo-olefine ketones, which yield a-diketones on hydrolysis (B. 34, 2092).
Vinyl Ethyl, Vinyl Propyl, Vinyl Isopropyl Ketone, CH2:CHCOR, b.p.47 31°,
b.p.10 24°, and b.p.10 32°, are produced from j8-chloropropyl ethyl ketone, j8-chloro-
propyl propyl ketone, and /J-chloropropyl isobutyl ketone. They all easily
undergo polymerization.
Allyl Methyl Ketone, b.p. 108°, Allyl Ethyl Ketone, b.p. 127°, and Allyl Propyl
Ketone, b.p. 147°, CH2:CH.CH,COR, are readily changed by mineral acids into
Propenyl Methyl Ketone, b.p. 121°, Propenyl Ethyl Ketone, b.p. 137°, and Propenyl
Propyl Ketone, b.p. 157°.
Ethylidene Acetone, CH3CH=CH.CO.CH3, b.p. 122°. It has a penetrating
odour like that of crotonaldehyde. It is formed when hydracetyl acetone (q.v.)
is boiled with acetic anhydride or anhydrous oxalic acid (B. 25, 3166; 34, 2092).
Isobutylidene Acetone, (CH3)2CH.CH:CH.COCH3> b.p.18 51° (C. 1900, 1. 403). Iso-
amylidene Acetone (CH8)2CH.CH2CH:CHCOCH3, b.p. 180° (B. 27,R. 121 ; C. 1897,
I. 365). Heptachlorethylidene Acetone, CHC12CC1=CC1.CO.CC13, b.p.14 184°, results
when trichloracetyl tetrachlorocrotonic acid is heated with water (B. 25, 2695).
Mesityl Oxide, (CH3)2C=CH.CO.CH3, b.p. 130°, is a liquid smelling like
peppermint. Phorone, (CH3)2C=CH.CO.CH=C(CH3)2, m.p. 28°, b.p. 196°.
These are formed simultaneously on treating acetone with dehydrating agents,
e.g. ZnCl2, H2SO4, and HC1. Hydrochloric acid is best adapted for this
purpose, the acetone being saturated with it, while it is cooled. The addi-
tion products which are first formed, (CH3)aCCl.CH2.COCH8 and (CH3)2CC1.-
CH2.CO.CH2.CC1(CH3)2, are decomposed by alkali hydroxides, and the mesityl
oxide and phorone then separated by distillation. When acetone is condensed
by lime or sodium ethylate there is produced along with the mesityl oxide a cyclic
ketone isomeric with phorone, called isophorone (Vol. II.). Camphorphorone
is also isomeric with these two phorones. Mesityl oxide is also produced when
diacetone alcohol (^.v.)and diacetonamine (p. 230) are heated alone; also, together
with acetone, when phorone is heated with dilute sulphuric acid, which eventu-
ally causes it to break down into two molecules of acetone, as the result of water
absorption (A. 180, i) ; also by the action of isobutylene on acetic anhydride
in the presence of a little ZnCla (B. 27, R. 942). Mesityl oxide combines with
ammonia to form diacetonamine (p. 230) and with hydrazine to trimethyl
pyrazoline (Vol. II.). Mesityl oxide takes up two and phorone four bromine
atoms. Just as acetone condenses to mesityl oxide and phorone, so the homo-
logous ketones, and methyl ethyl ketone, methyl propyl ketone, methyl heptyl
ketone, and methyl nonyl ketone are condensed by hydrochloric acid (B. 36,
2555) or zinc chloride, and acetyl chloride (C. 1903, II. 566) to homologues of
mesityl oxide and phorone.
230 ORGANIC CHEMISTRY
Historical. — Kane discovered mesityl oxide in 1838, when he obtained it,
together with mesitylene, by the action of concentrated sulphuric acid on acetone.
At that time he regarded acetone as alcohol, and called it mesitalcohol. In mesityl
oxide and mesitylene, Kane thought he had discovered bodies which bore the
same relation to mesityl alcohol or acetone that ethyl ether or ethyl oxide and
ethylene bear to ethyl alcohol. KekuU developed the formula (CH3)2.C =CH.CO.-
CH for mesityl oxide, which was substantiated later by Claisen. Baeyer discovered
phorone, and Claisen assigned to it the formula (CH8)8C=CH.CO.CH=C(CH3)a
(A. 180, i).
THE ACTION OF AMMONIA ON MESITYL OXIDE AND PHORONE
Ammonia unites with these bodies at their double bonds and forms three
bases, Diacetonamine. Triacetonamine, and Tnacetone Diamine — the same
that are formed from ammonia and acetone (Heintz, A. 174 133 ; 198, 42 ; 203,
336). There are two possible courses that the reaction may follow : firstly,
that the acetone is condensed to mesityl oxide and phorone by the ammonia
which then become converted into the amines, or secondly, the ammonia forms
OH
a simple addition compound, (CH3)2C<NH , which then condenses.
CH3V NH8 CH3X /CH.COCH.
>C<
\NH2
Diacetonamine.
3V /CH2.CO.CH2 /CH3
3V
>C=CHCOCH8 -
CH/ CH/ \NH2
Mesityl oxide. Diacetonamine.
CH8V /CH, /r
>C=CH.CO.CH=C< - ^ CH NH" CH8
CH/ N:H8 \
Phorone. ^ Triacetonamine.
CH3V /C2.CO.CHav /CH8
CH/ NH2 NH
Triacetone diamine.
(A. 203, 336.)
Diacetonamine forms a colourless liquid, slightly soluble in water, which is
decomposed into mesityl oxide and ammonia by distillation (B. 7, 1387). It
shows a strongly alkaline reaction and forms crystalline salts with one equivalent
of acid. The hydrochloride, acted on by potassium nitrite, yields Diacetone
Alcohol, (CH3)2C(OH)CH2COCH8 (q.v.), which can be considered to be a derivative
of diacetonamine. It loses water and changes to mesityl oxide. Urea derivative
of diacetonamine, see B. 27, 377. Diacetonamine Oxime, m.p. 55°, b.p.12 121°
(B. 34, 300, 792).
Oxidation by chromic acid mixture produces amino-isobutyric acid,
(CH8)2C(NH2)COOH (propalanine), and amino-isovaleric acid, (CH3)2C(NH2).-
CH2COOH.
Triacetonamine, m.p. 39-6° • NH2O, m.p. 58°, is prepared from phorone and
ammonia, and is an imide base (p. 165). It crystallizes anhydrous in needles,
and with one molecule of water in large quadratic tables. It is weakly alkaline.
Its hydrochloride with potassium nitrite yields a nitrosamine compound,
C,H16ON.NO, m.p. 73°, which regenerates phorone when boiled with sodium
hydroxide. The nitroso-body is transformed by hydrochloric acid back into
triacetonamine. This substance, with bromine, forms N-Bromotriacetonamine,
C9H16ONBr, m.p. 44° (B. 31, 668). For further reactions, see Vol. II.
Phorone and primary amines produce n-Methyl Triacetonamine, etc. (B. 28,
R. 1 66). Just as the reaction of diacetonamine with acetone yields triacetonamine,
so acetaldehyde produces Vinyl Diacetonamine (B. 17, 1788).
(CH3)2C.CH2COCH8 CH8CHO (CH3)2C.CH2CO.CHS
NH2 NH -- CHCH,
With cyanacetic ester an analogous 8-lactam is formed (B. 26, R. 450).
ACTION OF HYDROXYLAMINE ON MESITYL OXIDE 231
ACTION OF HYDROXYLAMINE ON MESITYL OXIDE AND PHORONE
According to the conditions of experiment, hydroxylamine becomes added
on to the mesityl oxide molecule and gives Diacetone Hydroxylamine, or else oxime
formation takes place. In the case of phorone, however, only addition compounds
are formed — Triacetone Hydroxylamine and Triacetone Dihydroxylamine, corre-
sponding with the two compounds obtained with ammonia.
Mesityl Oxide Oxime, (CH3)2C=CH.C(NOH)CH3, a-form, b.p., 83°, £-form,
m.p. 49°, b.p.9 92°, is prepared from mesityl oxide and free hydroxylamine. It is
obtained in two modifications. The oily a-oxime is transformed into the solid
jS-form by the action of heat on the hydrochloride, or by repeated distillation
under reduced pressure. This body, acted on by hydroxylamine hydrochloride
and boiled with alkali, regenerates the a-modification.
Mesityl Nitrimine,(CH.z}zC=CB..C<^^Q , m.p. 155°, with rapid decomposi-
tion, is produced when both modifications of mesityl oxide oxime are treated
with amyl nitrite in glacial acetic acid (B. 32, 1336). Reduction changes it to
Trimethyl Pyrazoline (Vol. II.). Heated with water it forms an isomeric keto-
trimethyl dihydro-isoxazole oxime (Vol. II.); oxidation with nitric acid changes
it to Nitrilomesityl Dioxime Peroxide. This is converted by aniline in glacial
acetic acid solution into Anilonitro-acetone, which, in turn, is changed by sul-
phuric acid into nitro-acetone, (A. 319, 230), a derivative of hydroxy-acetone :
(CHS)2C.CH2C --- CH CH8C— — CHaNO, CH8CO.CH,NO2.
ONO N.O.O.N N.CaH5
, m.p. 162° (B. 33, 1338).
PTT CH COCH
Diacetone Hydroxylamine, ^^ *' m'p< 52°' b'P'io 95°, is formed,
together with a-mesityl oxide oxime, by the action of free hydroxylamine on
mesityl oxide. Oxidation with chromic acid yields :
p-Nitroso-isopropyl Acetone, *>£<r~~*, dimolecular form,
m.p. 75° ; monomolecular form, b.p.u 60°, which is also formed from diacetonamine
(p. 230) by oxidation with persulphuric acid. In the dimolecular condition it
forms white tabular crystals, which melt to a blue monomolecular liquid. It is
easily decomposed (comp. nitrosoparafnns, p. 153, and B. 36, 1069).
fi-Nitro-isopropyl Acetone, (CH8)aC(NO2)CH2COCH8, b.p.17 119°, is produced
when diacetone hydroxylamine is oxidized with nitric acid. It can be reduced
back to its parent compound by aluminium amalgam (B. 36, 158).
Triacetone Hydroxylamine, ctt*>C<CH*^O^H*>C<CHl' m'p> 5°°' is
prepared from phorone and hydroxylamine hydrochloride, and yields with hy-
droxylamine, an oxime, m.p. 126*.
Triacetone Dihydroxylamine, c
b.p. 20 I35° (B- 36, 657), results from interaction of phorone and two molecular
proportions of free hydroxylamine. Reduced by Zn and HC1, it changes to
triacetone diamine. Boiled with alkalis it gives :
PTT /CHj— — CO - L/Hjv PW
Triacetone Dihydroxylamine Anhydride, rS3><X >C<rS*
CH» \NH - O - HN/ H«
or S53>C/ 2 || 2N>C<rS8' m.p. in0. Reduction by Zn and HC1
'H« \NH— 00— HN/ 'Hs
gives triacetone diamine (see above).
Dinitrosodiisopropyl Acetone, cH3>C<NOS"~C°"~CON>C<CHl' m'P' I32*»
is produced from triacetone dihydroxylamine by chromic acid (B. 31, 1379)'
On melting it forms a deep blue liquid.
The scheme on which this work is based requires that diacetonamine and
diacetone hydroxylamine should be discussed as derivatives of diacetone alcohol
ORGANIC CHEMISTRY
with the ketoles ; and triacetonamine, triacetone diamine, triacetone hydroxyl-
amine, and triacetone dihydroxylamine, etc., as derivatives of the still unknown
triacetone dialcohol among the ketodioles. They have, however, been examined
before the olefine ketones, on account of their genetic connection with mesityl
oxide and phorone.
Allyl ^ce/ow0,CH2:CH.CH2.CH2COCH3, is obtained from allyl acetoacetic
ester. It is isomeric with mesityl oxide (C. 1898, II. 663 ; B. 33, 1472).
Methyl Heptenone, (CH3)aC=CH.CH2.CH2COCH3, b.p. 173°, is found in a
number of ethereal oils which contain citral, linalool, and geraniol. It results
from the distillation of cincolic anhydride (Vol. II.). Synthetically it can be
produced by the action of sodium hydroxide solution on the reaction product
of sodium acetyl acetone on amylene dibromide, (CH3)2CBr.CH2CH2Br (B. 29,
R. 590). It is also prepared from dimethyl allyl acetoacetic ester, the result
of the reaction between acetoacetic ester and amylene dibromide, and sodium
ethoxide solution (B. 34, 594). It possesses a penetrating odour like amyl
acetate. Oxidation with KMnO4 breaks it down to acetone and laevulinic acid ;
zinc chloride produces dihydro-m-xylol (A. 258, 323 ; B. 28, 2115, 2126).
Sorbic Ethyl Ketone, CH3.CH:CH.CH:CH.CO.C2H5, b.p.26 93°, is prepared
from sorbyl chloride and zinc ethyl (B. 34, 2222).
Condensation of the respective a/J-olefine aldehydes (p. 214) with acetone
leads to the formation of the following diolefme ketones (B. 28, R. 608 ; C. 1906,
II. 1112) :
(1) TM ethyl Sorbic Methyl Ketone, CH3CH:C(CH8)CH:CHCOCH2, b.p.12 92°.
(2) ye-Dimethyl Sorbic Methyl Ketone, (CH3)CH2CH:C(CH8)CH:CHCO.CH3,
b.p. 8 97°-
(3) ye-Diisopropyl Sorbic Methyl Ketone, (C3H7)CH2CH:C(C8H7)CH:CHCOCH3.
Boiling with zinc chloride gives rise to benzene derivatives with varying
facility : (i) no condensation ; (2) a bad yield ; (3) a better one (see Vol. II.).
Diallyl Acetone, CH,=CH.CH2.CHaCOCH2.CH2.CH==CH2, b.p.70 116°, is
prepared from diallyl acetone carboxylic ester (comp. Oxetone).
Pseudo-ionone is also a diolefine ketone, and is described in Vol. II., together
with the olefine terpenes.
30. Acetylene Ketones.
These are obtained by the action of acid chlorides on sodium compounds
oi alkyl acetylene.
Acetyl (Enanthylidene, CH8[CH2]4C=EC.COCH3, b.p.18 93°, is obtained from
sodium cenanthylidene and acetyl "chloride. It possesses an irritating odour.
Dilute H2SO4 con verts it into acetyl caproyl methane, CH3[CH2]4CO.CH2COCH3
(C. 1900, II. 1231, 1262). Hydroxylamine and hydrazines combine with the
acetylene ketones, forming isoxazoles and pyrazoles respectively (C. 1903, II. 122 ;
1904, I- 43).
4. MONOBASIC CARBOXYLIC ACIDS
The organic acids are characterized by the atomic group, CO.OH,
called carboxyl, of which the hydrogen can be replaced by metals and
alcohol radicals, forming salts and esters. These organic acids may
be compared to the sulphonic acids (p. 146), which contain the
sulpho-group, SO2.OH.
The number of carboxyl groups present in them determines their
basicity, and distinguishes them as mono-, di-, tri-basic, etc., or as
mono-, di-, and tri-carboxylic acids :
CH3.C02H C
a \C02H.
Acetic Acid Malonic Acid Tricarballylic Acid
(Monobasic). (Dibasic). (Tribasic).
MONOBASIC CARBOXYLIC ACIDS 233
The monobasic saturated acids can be looked on as being combina-
tions of the carboxyl group with alcohol radicals ; they are ordinarily
termed fatty acids. They correspond with the saturated primary
alcohols and aldehydes. The unsaturated acids of the acrylic acid
and propiolic acid series, corresponding with the unsaturated primary
alcohols and aldehydes, are derived from the fatty acids by the loss
of two and four hydrogen atoms.
They are distinguished as :
A. Paraffin monocarboxylic Acids, CnH2nO2, formic acid or acetic
acid series.
B. Olefine monocarboxyhc Acids, CnH2n_2O2, oleicor acrylic acid series.
C. Acetylene monocarboxylic Acids, CnH2n_4O2, propiolic acid series.
D. Diolefme carboxylic Acids, CnH2n_4O2.
Nomenclature. — The " Geneva nomenclature " deduces the names
of the carboxylic acids, just like the alcohols (p. 102), the aldehydes
(p. 193), and the ketones (p. 218), from the corresponding hydro-
carbons ; thus formic acid is [methane acid] and acetic acid is [ethane
acid], etc.
The radical of the acid is the residue in combination with the
hydroxyl group :
CHS.CO— CH3.CH2.CO— CH3.CH2.CH2.CO—
Acetyl. Propionyl. Butyryl.
The names of the trivalent hydrocarbon residues, which in the acid
residues are united with oxygen, are indicated by the insertion of the
syllable " en " into the names of the corresponding alcohol radicals :
CH3.C= CH3.CHj.C= CHa.CH2.CH2.=
Ethenyl. Ethylmethenyl. n-Propylmethenyl.
The group CEE, however, is not only called the methenyl group,
but also the me thine group.
Review of the Derivatives of the Monocarboxylic Acids.—
Numerous classes of bodies can be derived by changes in the carboxyl
group. In connection with the fatty acids mention will only be made
of the salts. The other classes of derivatives will be considered as
such after the fatty acids. They are :
(1) The esters, resulting from the replacement of hydrogen in the
carboxyl group by alcohol radicals (p. 265).
(2) The chlorides (bromides, iodides, and fluorides), which are com-
pounds of the acid radicals with the halogens (p. 269) .
(3) The acid anhydrides (p. 271), compounds of the acid radicals
with oxygen.
(4) The acid peroxides (p. 273).
(5) The thio-acids (p. 273), compounds of the acid radicals with SH.
(6) The carbithionic acids.
(7) The acid amides (p. 274), compounds of the acid radicals with
itj.
(8) The acid nitrites (p. 278).
Hence acetic acid yields the following :
CH3.C02.C2H6 2. CH3.COC1 3. (CH3.CO)20 4. (CH3.CO)2Oa
Acetic Ethyl Ester. Acetyl Chloride. Acetic Anhydride. ^Acetyl Peroxide.
5. CH3.COSH 6. CH3.CSSH 7. CH3.CONH2 8. CH3.C^N
Thioacetic Acid. Methyl Carbithionic Acetamide. Acetonitrile.
Acid.
234 ORGANIC CHEMISTRY
Besides the acid halides, amides, and nitriles, there exist the following more
complex derivatives : —
(9) Hydrazides (p. 278); (10) azides (p. 278); (n) amide chlorides (p. 281);
(12) imide chlorides (p. 281); (13) imido-ethers (p. 281); (14) thio-amides (p.
282); (15) thio-imido-ethers (p. 282); (16) hydroxamic acids (p. 282); (17)
hydroxatnoximes (p. 283); (18) nitrosolic acids (p. 283); (19) nitrolic acids
(P- 283); (20) hydroxamyl chlorides (p. 283); (21) amidoximes (p. 283); (22)
amidines (p. 282) ; (23) hydrazidines (p. 284) ; (24) formazyles, and others: —
//° ,/> y^
9. CH3C< 10. CH3cf /N ii. CH3Cr
XNHNH2 XN< || XNH2
XN
Acetohydrazidc. ' [Acetazide]. Acetamide Chloride.
/Cl /OC2H5 /NH,
12. CH3C< 13. CH3C/ 14. CH3C<;
XNH ^NH ^S
Acetimide Chloride. Acetimido-ether. Thioacetamide.
/SCaH6 /OH /NHOH
15. CH3C< 16. CH3C4 17. CH3C
^\XTTJ X>-\T/-^TT
Thioacetimido Acetohydroxamic Acetohydroxamic
Ether. Acid. Oxime.
/NO /N02
1 8. CH,C^ 19. CHjC^ 20. CH
Acetonitrosolic Ethyl Nitrolic Acetohydroximic
Acid. Acid. Acid Chloride.
xNH, ^NH, /NH2
^NOH 8 ^NH ^N.NHC0H5
Acctamide Oxlme. Acetamidine. Acetohydrazidine.
24. CH3QC etc.
^N.NHC6H5
Methyl Forraazyl.
Aromatic carboxylic acids, especially benzoic acid, are particularly
suitable for the preparation of carboxylic acid derivatives, and various
classes of substances which actually belong here, have been discovered
and more closely studied in that series. Benzoic acid transmits its
own facility in crystallization to its derivatives, so that the process of
investigation becomes the easier.
Similarly, the aromatic amines and hydrazines, such as aniline,
toluidine, and phenylhydrazine, are more easily prepared and more
convenient to manipulate than the corresponding aliphatic com-
pounds, so that in this direction also the benzene derivatives have
been more closely investigated than the simple methane compounds.
Numerous derivatives are also obtained by the replacement of the
hydrogen atoms in the radical combined with hydroxyl by other
atoms or groups. Only the halogen substitution products will be de-
scribed under the fatty acids, after the discussion of the various classes
mentioned in the preceding paragraphs.
The fatty acids can be recovered from all of the above classes of
derivatives by simple reactions.
It has already been indicated under the oxygen derivatives of the
methane hydrocarbons, that aldehydes, ketones, and carboxylic acids
may be considered to be anhydrides of theoretical, non-existing diacid
or tnacid alcohols, in which the hydroxyl groups are attached to the
MONOBASIC SATURATED ACIDS 235
same carbon atom (p. 99). The aldehydes and ke tones were here
especially referred to, because there were, among their acetals (p. 205)
and the orthoketone alkyl ethers (p. 225), for example, stable ethers
of glycols or ortho aldehydes and of orthoketones, ordinarily non-
existent in the free state, among which chloral hydrate itself is
included.
The trihydric alcohols, corresponding with the carboxylic acids,
cannot exist, but ethers of them are known. The hypothetical,
trihydric alcohols, of which the carbonic acids may be considered
anhydrides, have been called ortho acids, comparably to tribasic
phosphoric acid being termed orthophosphoric acid (A. 139, 114 ; J.
(1859) I52 • B. 2, 115). This designation has also been applied to
the orthoaldehydes and orthoketones.
It is customary, therefore, to speak of " hypothetical orthoformic
acid " and of " orthoformic esters " (the esters of tribasic formic acid),
of formic acid — which, in reference %o the relation of orthophosphoric
to metaphosphoric acid, PO(OOH), might be termed metaformic acid —
and of formic acid esters :
/OH /OC2H6 /OH /OC2H6
HC^-OH HCr-OC2HB CH< CH<
XCH XOC2H6 X) X)
Orthoformic Acid. Orthoformic Ethyl Formic Acid. Formic Ethyl
Ester. Ester.
The chloride, bromide, and iodide corresponding with orthoformic
acid are chloroform, bromoform, and iodoform ; further derivatives are
nitroform, orthotrithioformic ester, formyl trisulphonic acid, and others :
/NOa /SC2H6 /SO3H
HC^NO, HC^-SC2H5 HCc-SO3H
C1 XN02 XSC2H5 XS08H
Chloroform. Nitroform. Orthotrithioformic Formyl Trisulphonic
Ester. Acid.
It is only in the case of formic acid that the ortho-acid derivatives
require a special designation. They will be discussed immediately
following the derivatives of the ordinary formic acid.
Comparably to the above, substances are known which are derived
from orthoacetic acid, CH3C(OH)3 :
CH3C(OC2H5)3 CH3CCla CH3C(NOa), CH8C(NC5H10),
Orthoacetic Ethyl Methyl Methyl Orthoacetic
Ester. Chloroform. Nitroform. Piperidide.
A. MONOBASIC SATURATED ACIDS, PARAFFIN MONOCARBOXYLIC
ACIDS, CnH2n+1.CO,H
Formic acid, H.CO.OH, is the first member of this series. The
radical HCO, which, here, is united to hydroxyl, is called formyl.
This acid is distinguished from all its homologues and the unsaturated
monocarboxylic acids, in that it exhibits not only the character of a
monobasic acid, but also that of an aldehyde. To express in a name its
aldehyde character the acid might be designated hydroxyformaldehyde,
H0.<
From a chemical standpoint, this acid is more closely connected
236 ORGANIC CHEMISTRY
with glyoxylic acid, CHO.CO2H (q.v.) than to acetic acid. Therefore,
formic acid and its derivatives will be treated before acetic acid and
its homologues are discussed.
FORMIC ACID AND ITS DERIVATIVES
It is not only the aldehyde character which distinguishes formic
acid from acetic acid and its homologues, but it is also the absence of
a chloride and anhydride, corresponding with acetyl chloride (q.v.) and
acetic anhydride (q.v.). The withdrawal of water from formic acid
leads to the formation of carbon monoxide, a reaction which does
not take place in the case of any of the higher homologues.*
Hydrocyanic acid, the nitrile of formic acid, has an acid nature, and
therein differs from the indifferent nitriles of the homologous acids.
Formic acid is twelve times stronger than acetic acid, as is shown by
the affinity constants derived from the electric conductivity (Ostwald),
To the section on formic acid will be appended carbon monoxide,
and its nitrogen-containing derivatives, the isonitriles or carbylamines,
C=N— R', andfulminic acid, C=NOH.,
Formic Acid, H.CO.OH [Methane 'Acid] (Acidum formicum), m.p.
8*6° (crystallizes at o°), b.p.10o 100 6°, D2o=r22, is found free in ants,
in the procession caterpillar, Bombyx processionea, in pine needles,
and in various animal secretions (perspiration), from all of which it
may be obtained by distillation with water. It is almost certainly not
present in stinging nettles [TR.].
It is produced in the laboratory :
(1) By the oxidation of methyl alcohol and formaldehyde (B. 36,
3304):
H.CH8OH - > H.CHO - > H.CO,H.
(2) By heating hydrocyanic acid, the nitrile of formic acid, with
alkalis or acids :
HCN+2H20=HCOOH+NH3.
(3) By boiling chloroform with alcoholic potassium hydroxide
(Dumas) :
CHCl3+4KOH=HCOOK+3KCl+2HaO.
(4) From chloral (Liebig), (5) from acetaldehyde disulphonic acid
(see p. 208), and (6) from propargylic aldehyde (p. 215) and sodium
hydroxide :
CCls.CHO+NaOH=HCCl8+HCOONa;
(SOaNa)JCH.CHO+NaOH = (S08Na)1CH,+HCOONa;
CH==C.CHO+NaOH =CHE=CH -fHCOONa.
Remarkable and of technical importance is (7) the direct production
of formates by the action of CO on concentrated potassium hydroxide
at 100°, or more easily on soda-lime at 200-220° (Berthelot, A. 97, 125 ;
Geuther, A. 202, 317 ; Merz and Tibirifd, B. 13, 718) :
CO+NaOH=HCO.ONa.
(8) By action of acids on isocyanides or carbylamines (p. 247) :
_ CN.C,H6 +2H,0 =HCOaH +C1H,NHa.
' Di'Ketah or Carbon Suboxide (Vol. I.),
FORMIC ACID AND ITS DERIVATIVES 237
(9) From fulminic acid by means of concentrated hydrochloric
acid (see For my 1 Chloridoxime, p. 244), hydroxylamine hydrochloride
being formed simultaneously :
C=N.OH+2H20+HC1=H.C02H+NH2OH.HC1.
(ioa) By the reduction of moist carbon dioxide (carbonic acid) by
potassium (Kolbe and Schmitt, A. 119, 251) :
3C02+4K+HaO=2HCO.OK + K2C08.
Formates are also produced by the action of sodium amalgam or electrolytic
hydrogen (B. 38, 4138) on ammonium carbonate and an aqueous solution of
primary carbonates ; likewise on boiling zinc carbonate with potassium hydroxide
and zinc dust.
(io&) Potassium hydride combines at ordinary temperatures with CO2,
forming HCOOK. At higher temperatures (80°) there results a mixture of
potassium formate and oxalate (C. 1905, II. 29). Potassium formate is also
formed when CO and H2 are passed together over heated potassium (Moissan
C. 1902, I. 568):
(n) Formic acid is best prepared from oxalic acid, by heating it
with glycerol.
Oxalic acid heated alone decomposes into carbon dioxide and formic acid, or
carbon monoxide and water, the latter decomposition preponderating :
COOH ^
COOH ~
When, however, the acid is heated with glycerol in a distillation flask to
1 00-110°, glyceryl monoxalic ester is first formed, and afterwards by loss of
carbonic acid, mono-formin, the monoformic ester of glycerol :
CHj.OCO.COjH
CHOH =
CH2OH
CH2O.COH+CO,
CHOH
CH2OH
On further addition of crystallized oxalic acid the latter again breaks up into
the anhydrous acid and. water, which converts the glycerol formic ester into
glycerol and formic acid :
C3H6O.CHO(OH)24-H,O=C8H6(OH)8+CHO.OH.
At first the acid is very dilute, but later it reaches 56 per cent. If anhydrous
oxalic acid be employed at the beginnmg, a 95-98 per cent, formic acid is produced.
To obtain anhydrous formic acid, the aqueous product is boiled with lead
oxide or lead carbonate. The lead formate is then decomposed, at 100°, by a
current of hydrogen sulphide. Or, formic acid of high percentage may be
dehydrated by means of boric anhydride (B2O8) (B. 14, 1709) ; or, finally, sodium
formate may be decomposed by sulphuric acid (C. 1905, I. 1701).
Formic acid is a mobile liquid which possesses a pungent odour
and causes blisters on the skin. It mixes in all proportions with water,
alcohol and ether, and yields the A)'^ra^4CH2O2+3H2O, b.p.760 107*1°,
with dissociation into formic acid and water. Concentrated hot
sulphuric acid decomposes formic acid into carbon monoxide and water.
238 ORGANIC CHEMISTRY
A temperature of 160° suffices to break up the acid into carbon dioxide
and hydrogen. The same change may occur at ordinary temperatures
by the action of finely divided rhodium, iridium, and ruthenium, but
less readily when platinum sponge is employed.
The aldehydic nature of formic acid explains its reducing property,
its ability to precipitate silver from a hot neutral solution of silver
nitrate, and mercury from mercuric nitrate, being itself oxidized to
carbon dioxide :
/H o /OH
HO.C/ - ^HO.Qf - ^C02+H20.
Formates, excepting the sparingly soluble lead and silver salts, are readily
soluble in water. Lead formate, (HCO2)2Pb, crystallizes in beautiful needles
and dissolves in 36 parts of cold water. Silver formate, HCO2Ag, rapidly blackens
on exposure to light.
Decomposition of Formates. — i. The alkali salts, heated to 250°, are converted
into oxalates with evolution of hydrogen :
2HC02K=(COaK)2+Ha.
2. Potassium formate, when heated with an excess of potassium hydroxide,
decomposes with the formation of carbonate and the liberation of pure hydrogen
(see Inorganic Chemistry) :
H.COaK + KOH = KaC03+Ha.
3. The ammonium salt, heated to 230°, passes into formamide 3
-H20
H.CO2NH4 - - — > H.CONH,.
330*
It may be distilled undecomposed under reduced pressure.
4. The silver salt and mercury salt, when heated, decompose into metal,
carbon dioxide and formic acid (C. 1905, II. 304) :
2HC02Ag=2Ag+COa+H.C02H.
5. The calcium salt, when heated with the calcium salts of higher fatty acids,
yields aldehydes (p. 190).
Monochloroformie aeid, Cl.COOH, is regarded as chlorocarbonic acid. It will
be discussed after carbonic acid.
Esters of Formic Acid are prepared (i) from formic acid, alcohol,
and hydrochloric or sulphuric acid ; (2) from sodium formate and
hydrochloric or sulphuric acid ; (3) from a mixture of formyl acetic
anhydride, or acetyl formyl oxide, HCOOCOCH3, and alcohols (C. 1900,
II. 314) ; (4) from glycerol, oxalic acid, and alcohol. They are
agreeably smelling liquids.
Formic Methyl Ester, m.p. — ioo0, b.p. 32-5° (B. 33, 638).
Formic Ethyl Ester, b.p. 54*4°.
This ester serves in the manufacture of artificial rum and arrack, and for the
union of the formyl group with organic radicals (see formyl acetone, etc.).
n-Propyl Ester, b.p. 81°. n-Butyl Ester, b.p. 107°. For higher esters consult
A. 233, 253 ; C. 1900, II. 314. The allyl ester, b.p. 90°.
Formamide, HCO.NH2, b.p. 192-195°, with partial decomposition,
b.p.10 90°, the amide of formic acid (comp. Acid Amides) is obtained
(i) by heating ammonium formate (see above) to 230° (B. 12, 973 ;
FORMIC ACID AND ITS DERIVATIVES 239
15, 980), or (2) ethyl formic ester with alcoholic ammonia to 100° ;
(3) by boiling formic acid with ammonium thiocyanate (B. 16, 2291).
It consists of a thick liquid, miscible with water, alcohol, and ether.
Heated rapidly it breaks down into CO and NH3 ; P2O5 liberates
hydrocyanic acid from it. It combines with chloral (p. 201) to form
Chloral Formamide, CC13.CH(OH)NHCHO, m.p. 115°, which is
employed as a narcotic.
Mercuric oxide dissolves in it with the formation of mercury formamide,
(CHO.NH)jjHg. It is a feebly alkaline liquid, sometimes applied as a sub-
cutaneous injection. For sodium formamide, see C. 1898, I. 927.
Ethyl Formamide, CHO.NH.C2H5, b.p. 199°, is obtained from ethyl formic
ester ; also by distilling a mixture of ethylamine with chloral :
CCls.CHO+NH2.CaH5=CHO.NH.CaH6+HCCl,.
Allyl Formamide, b.p.15 109° (B. 28, 1666).
Formyl Hydrazine, HCO.NHNH2, m.p. 54°, is obtained from formic
ester and hydrazine. It yields triazole (B. 27, R. 801) when heated
with formamide.
Diformyl Hydrazine, HCONH.NHCOH, m.p. 106°, is obtained
from an excess of formic ester and hydrazine, when heated to 130°
(B. 28, R. 242). Its lead salt with ethyl iodide yields Diformyl Diethyl-
hydrazine (B. 27, 2278).
Hydrocyanic Acid, Prussic Acid, Formonitrile, HNC, the nitrile
of formic acid (see acid nitriles), solidifies —15°, b.p. 26*5°, D18=o*697,
is a powerful poison. It occurs free accumulated in all parts of the
Javanese tree, Pangium edule, Reinw. (B. 23, 3548). It is obtained
(i) from amygdalin (q.v.}, a glucoside contained in bitter almonds, which,
under favourable conditions, takes up water and breaks down into
hydrocyanic acid, lavulose, and bitter almond oil or benzaldehyde (Liebig
and Wohler, A. 22, i). An aqueous solution, thus obtained, containing
very little hydrocyanic acid, constitutes the officinal aqua amygdalarum
amararum ; its active ingredient is hydrocyanic acid. (2) By the
action of phosphorus pentoxide on formamide ; (3) synthetically,
by subjecting a mixture of acetylene and nitrogen to the influence of
the 'electric spark (Berthelot], or by passing it through an electric
furnace (C. 1902, I. 525) ; (4) from cyanogen and hydrogen under the
influence of the silent electric discharge ; (5) when chloroform is
heated, under pressure, with ammonia ; (6) upon boiling formoxime
(p. 213) with water :
i. CaoH27NOn+2H2O=HNC+C6H6CHO+2C,HiaO.
Amygdalin. Benzaldehyde. Laevulose.
2. HCONH2 - > HNC+H,O
3. CH=CH + N2=2HNC
4. CN.CN + Ha=2HNC
5. HCC13 +5NH8=NH4NC-HNH4C1
6. H2C=N.OH =HNC +HaO.
Hydrocyanic acid is prepared from metallic cyanides, particularly
yellow prussiate of potash or potassium ferrocyanide, by the action of
dilute sulphuric acid :
2K4Fe(CN)8+3HaS04«KaFe2(CN)a+3KaSO4-i-6HNC.
240 ORGANIC CHEMISTRY
The aqueous acid thus obtained may be dehydrated by distillation
over calcium chloride or phosphorus pentoxide.
Historical. — Scheele discovered hydrocyanic acid in 1 782. Gay-Lussac, in 181 1,
obtained it anhydrous, in the course of his memorable investigations upon the
radical cyanogen. In hydrogen cyanide he recognized the hydrogen derivative
of a radical, consisting of carbon and nitrogen, for which he suggested the
name cyanogtne (KVO.VOS, blue, yevva<a, to produce).
Properties. — Anhydrous hydrocyanic acid is a mobile liquid, pos-
sessing a peculiar odour resembling that of oil of bitter almonds, and
is extremely poisonous.
It is a feeble acid, imparting a faint red colour to blue litmus.
Carbon dioxide decomposes its alkali salts. Like the halogen acids, it
reacts with metallic oxides, producing cyanides. From solutions
of silver nitrate it precipitates silver cyanide, a white, curdy precipi-
tate (see Inorg. Ch.).
Reactions. — (i) The aqueous acid decomposes readily on standing,
yielding ammonium formate and brown substances. The presence of
a very slight quantity of stronger acid renders it more stable. When
warmed with mineral acids it breaks up into formic acid and ammonia :
HNC+2H2O=HCOOH+NH8.
(2) Dry hydrocyanic acid combines directly with the gaseous
halogen acids to form crystalline compounds (p. 244). With hydro-
chloric acid it probably yields Formimide Chloride (H.CC1=NH)2HC1
(B. 16, 352). The acid also unites with some metallic chlorides,
e.g. Fe2Cl6, SbCl5.
(3) Nascent hydrogen (zinc and hydrochloric acid) reduces it to
methylamine (p. 158).
(4) When hydrocyanic acid unites with aldehydes and ketones, the
double union between carbon and oxygen in the latter compounds is
severed, and cyanhydrins, the nitrites of a-hydroxy-acids , are produced.
These, by this means, are obtained by a nucleus synthesis. This rather
important synthesis has become especially interesting for the building
up of the aldoses, to which class of derivatives lasvulose belongs.
(5) Hydrocyanic acid, or potassium cyanide, unites with many
aj8-un saturated carboxylic acids and a/J-olefine ketones, producing
thereby saturated nitrilo-carboxylic acids and nitrilo-ketones, (A. 293,
338 ; B. 37, 4065 ; C. 1905, 1. 171).
For the application of hydrocyanic acid to the synthesis of aromatic
aldehydes, see these.
For further addition reactions of hydrocyanic acid, compare formimido ether
(p. 243) and isouretine (p. 244).
Constitution. — The production of hydrocyanic acid from formamide on the
one side, and its reconversion into ammonium formate, are proofs positive of
its being the nitrile of formic acid (see Acid Nitriles). Its formation from chloro-
form and from acetylene argue also for the formula H.C=N. The replacement
of hydrogen, combined with carbon, by metals is shown also by acetylene (p. 288)
and other carbon compounds containing negative groups, e.g. the nitroethanes
<p. 151). However, on replacing the metal atoms in the salts by alkyls, two
classes of derivatives are obtained. The one series has the alkyls united to
carbon, as required by the formula H.C=N : nitriles of monocarboxylic acids,
f.g*CH8.CN. In the other class the alkyls are joined to nitrogen: isonitriles
FORMIC ACID AND ITS DERIVATIVES 241
or carbylamines, e.g. CHSN=C. The latter are nitrogen-containing derivatives
of carbon monoxide, and will be discussed after this body. In many respects the
behaviour of hydrocyanic acid recalls that of the isonitriles, hence in recent
years the formula HN=C has also been assigned to it, and many of the reactions
of potassium cyanide conform better with the isonitrile formula, K.N=C, than
with K.C=N, the formula usually given to this salt (A. 287, 265). Potassium
cyanide and iodoalkyls or alkali alkyl sulphuric acids, when heated together
yield, in the main, the nitriles ; at a lower temperature the isonitriles are formed,
which change over into the nitriles at a higher temperature (C. 1900, II. 366).
The formation of acetonitrile from hydrocyanic acid and diazomethane is evidence
in favour of the nitrile formula of hydrocyanic acid (B. 28, 857).
Detection. — To detect small quantities of free hydrocyanic acid or its soluble
salts, the solution under examination is saturated with potassium hydroxide, a
solution of a ferrous salt, containing some ferric salt is added, and the mixture is
boiled for a short time. Hydrochloric acid is added to dissolve the precipitated
iron oxides ; if any insoluble Prussian blue should remain, it would indicate the
presence of hydrocyanic acid. The following reaction is more sensitive. A few
drops of yellow ammonium sulphide are added to the hydrocyanic acid solution,
and this then evaporated to dryness. Ammonium thiocyanate will remain, and
if added to a ferric salt, will colour it a deep red.
Polymerization of Hydrocyanic Acid. — When the aqueous acid stands for
some time in contact with alkali hydroxides, or with alkali carbonates, or if the
anhydrous acid be mixed with a small piece of potassium cyanide, not only
brown substances separate, but also white crystals, soluble in ether, and having
the same percentage composition as hydrocyanic acid. Inasmuch as they break
down, on boiling, into glycocoll, NH2.CH2CO2H, carbon dioxide and ammonia,
they are assumed to be the nitrile of amidomalonic acid, (CN)2CHNH2 (B. 7, 767).
They decompose at 180°, with explosion and partial reformation of hydrocyanic
acid.
Salts of Hydrocyanic Acid. — Cyanides and Double Cyanides. —
The importance of the cyanides and 'double cyanides in analytical
chemistry explains the reason for the discussion of hydrocyanic acid
and its salts in inorganic text-books. In organic chemistry the
metallic cyanides serve for the introduction of the cyanogen group
into carbon compounds (comp. acid nitriles, a-ketone acids, etc.).
The alkali cyanides may be formed by the direct action of these
metals on cyanogen gas ; thus, potassium burns with a red flame in
cyanogen, at the same time yielding potassium cyanide, C2N2+K2
=2 KNC. They are also produced when nitrogenous organic substances
are heated together with alkali metals. The strongly basic metals
dissolve in hydrocyanic acid, forming cyanides. A more common
procedure is to act with the acid on metallic oxides and hydroxides :
HNC + KOH=KNC+H20 ; 2HNC+HgO=Hg(CN)2+H8O.
The insoluble cyanides of the heavy metals are obtained by the double
decomposition of the metallic salts with potassium cyanide.
The cyanides of the light metals, especially the alkali and alkali
earths, are easily soluble in water, react alkaline, and are decomposed
by acids, even carbon dioxide, with elimination of hydrogen cyanide ;
yet they are very stable, even at a red heat, and undergo no change.
The cyanides of the heavy metals, however, are mostly insoluble, and
are only decomposed by strong acids. When ignited, the cyanides
of the noble metals undergo decomposition, breaking up into cyanogen
gas and metals.
The following simple cyanides are especially important in organic
chemistry :
VOL. I, R
242 ORGANIC CHEMISTRY
Potassium Cyanide, KNC (Consult v. Richter's " Inorganic
Chemistry " for method of preparation, properties, and technical
applications of this salt), is as poisonous as hydrocyanic acid itself.
The formation of potassium cyanide from the alkali metals and
nitrogenous carbon compounds depends on the primary formation
of potassium carbide, which then takes up nitrogen.
Its aqueous or alcoholic solution becomes brown on exposure to the air, and
decomposes, more rapidly on boiling, into potassium formate and ammonia.
When fused in the air, as well as with easily reducible metallic oxides, the salt
takes up oxygen and is converted into potassium isocyanate (q.v.}. On being
melted with sulphur, it forms potassium thiocyanate (q.v.). When the alkyl
halides or salts of alkyl sulphuric acid are heated with potassium cyanide,
acid nitriles with varying amounts of isomeric carbylamines or isonitriles are
produced. Many organic halogen substitution products are converted into
nitriles through the agency of potassium cyanide. Ethyl hypochlorite and
potassium cyanide yield chlorimidocarbonic ester, a reaction which argues for
the isonitrile formula of potassium cyanide (A. 287, 274).
Ammonium Cyanide, NH4NC, is formed by the direct union of HNC with
ammonia, by heating carbon in ammonia gas ; by the action of ammonia on
chloroform (p. 239) ; by the action of the silent electric discharge on methane
and nitrogen ; and by conducting carbon monoxide and ammonia through red-
hot tubes. It is best prepared by subliming a mixture of potassium cyanide
or dry ferrocyanide with ammonium chloride. It consists of colourless cubes,
easily soluble in alcohol, and subliming at 40°, with partial decomposition into
NHS and HNC. When preserved it becomes dark in colour and decomposes.
It unites with aldehydes and ketones with the elimination of water to form
a-amidonitriles, e.g. with formaldehyde it forms methylene amidoacetonilrile
(comp. Glycocoll).
Mercuric Cyanide, Hg(CN)2) is obtained by dissolving mercuric oxide in
hydrocyanic acid, or by boiling Prussian blue (8 parts) and mercuric oxide (i
part) with water until the blue coloration disappears. It dissolves readily
in hot water (in 8 parts cold water), and crystallizes in bright, shining, quadratic
prisms. When heated it yields cyanogen and mercury. It forms acetyl cyanide
with acetyl chloride (see Pyroracemic Acid).
Silver Cyanide, AgNC, combines with alkyl iodides to yield addition products,
which pass into isonitriles when they are heated (p. 247 ; C. 1903, II. 827).
The chief use of potassium cyanide is in the preparation of acid
nitriles of various kinds. This is done by bringing it into double
decomposition with alkylogens, alkyl sulphates, and halogen sub-
stitution products of the fatty acids. In many instances mercury
cyanide or silver cyanide is preferable, e.g. in the formation of a-ketonic
nitriles from acid chlorides or bromides. It is interesting to note that
by the interaction of alkyl iodides and silver cyanide isonitriles or
carbylamines are formed ; in them the alcohol radical is joined to
nitrogen. (See p. 247 for the explanation.)
Compound Metallic Cyanides. — The cyanides of the heavy metals, insoluble
in water, dissolve in aqueous potassium cyanide, forming crystallizable double
cyanides, which are soluble in water. Most of these compounds behave like
double salts. Acids decompose them in the cold, with disengagement of hydro-
cyanic acid and the precipitation of the insoluble cyanides :
AgCN.KCN+HNO3=AgCN+KNO3+HNC.
In others, however, the metal is in more intimate union with the
cyanogen group, and the metals in these cannot be detected by the
usual reagents. Iron, cobalt, platinum, also chromium and man-
ganese in their most highly oxidized state, form cyanogen derivative*,
FORMIC ACID AND ITS DERIVATIVES 243
of this class. The stronger acids do not eliminate hydrocyanic acid
from them, even in the cold, but the corresponding acids are set free,
and these are capable of producing salts :
K4Fe(CN)a+4HCl=H4Fe(CN)6+4KCl.
Many chemists refer these complex metallic acids to hypothetical,
polymeric hydrocyanic acids :
H— C=N H— C=N— C— H
N=C— H N=CH-N
Di-hydrocyanic Acid. Tri-hydrocyanic Acid.
pt<C2N2K
rS:2N2K
Potassium Potassium Potassium
Platinocyanide. Ferrocyanide. Ferricyanide.
The most important compound metallic cyanides, particularly
potassium ferrocyanide or yellow prussiate of potash, the parent sub-
stance for the preparation of cyanogen derivatives, have already
been described in the inorganic section of this text-book.
Hydroferrocyanic Acid, H4Fe(CN)6, is precipitated by ether, from
its solution in alcohol, as a pure white compound with ether (C. 1900,
II. 1151). This is decomposed at 90° in vacuo. It is assumed that
the union occurs at the oxygen atom, which behaves as a tetra-
valent substance (comp. pp. 127, 128 ; B. 34, 3612 ; 35, 93).
Sodium Nitroprusside, Fe(CN)5(NO)Na2+2H2O. — Hydronitroprus-
sic acid, of which the constitution has not yet been determined
(B. 29, R. 409), is formed when nitric acid acts on potassium ferro-
cyanide (C. 1897, I. 909). The filtrate from the potassium nitrate is
neutralized with sodium carbonate, and yields the salt in beautiful
red rhombic prisms, easily soluble in water.
It serves as a very delicate reagent for alkali sulphides and
hydrogen sulphide, with which it gives an intense violet coloration.
F or mimido- ether, formhydroxamic acid, formyl chloridoxime, methyl nitrolic acid,
formamidine, thioformethylimide, and formamidoxime are intimately related to
hydrocyanic acid and formamide. They are representatives of groups of bodies
which will be discussed in connection with acetic acid and its homologues.
Qp TT
The formimido-ethers, such as HC<^H2 5, are only known in the form of
hydrochlorides. They are obtained from hydrocyanic acid alcohol and HC1
(B. 16, 354. 1644) :
If a mixture of mercuric cyanide and chloride be treated with HC1 gas in
alcohol-ether solution, a double salt results, [HC(OC2H6) : NH]HCl.HgCla (C.
1904, I. 1064).
Upon standing in contact with alcohols they pass into esters of orthoformic
acid (q.v.). They yield amidines with ammonia and amines (primary and
secondary).
Thioformethylimide, HC<C H , b.p.14 125°, is produced by the union of
ethyl isocyanide, in alcoholic solution, with hydrogen sulphide. It is a yellow
oil, with an odour like that of sulphur (A. 280, 297).
Thioformic Acid, HCO.SH, is obtained as its sodium salt when formic
phenyl ester (Vol. II.) is hydrolyzed with alcoholic NaSH. The free acid is a
unstable liquid, which quickly polymerizes (C. 1905, I. 20).
Ci
244 ORGANIC CHEMISTRY
Formamidine, Methenyl Amidine, HC2, is only known in the form
of salts. Its hydrochloride is obtained (i ) by the action of ammonia on formimido-
ethyl ether hydrochloride (B. 16, 375, 164?) > (2) from formimide chloride, the
addition product of hydrochloric acid and hydrocyanic acid, when it is digested
with alcohol :
2.
Formhydroxamie Acid, HC<Q^H, m.p. 80°, is produced when equimolecular
quantities of formic ester and hydroxylamine are allowed to stand in a solution
of absolute alcohol ; also, by the oxidation of methylamine with persulphuric
acid (comp. p. 163) (B. 35, 4299). It forms brilliant leaflets, which dissolve
readily in water and in alcohol, but sparingly in ether. At temperatures above
its melting-point violent decomposition takes place, a change which occurs
slowly and completely at ordinary temperatures. The acid yields an intense
red coloration with ferric chloride. It reduces ' Fehling's solution, and its
mercury salt in dry condition explodes when it is rubbed ; copper salt, HCNO2Cu
(comp. B. 33, 1975).
Formyl Chloridoxime, HC<>j , is a beautifully crystallized, very easily
decomposed compound, with a sharp, penetrating odour. It is produced when
fulminates (p. 249) are treated, in the cold, with concentrated hydrochloric acid.
It dissolves in ether. When its solution is warmed with concentrated hydrochloric
acid, it rapidly decomposes into formic acid and hydroxylamine hydrochloride :
+2H20 =H.C<°R +NH2OH.HC1.
In aqueous solution the body readily reverts to fulminates. Silver nitrate
changes it to silver fulminate and silver chloride. Aniline converts it into
phenyl isouretine (Vol. II.), and with ammonia it yields cyanisonitrosoacet-
hydroxamic acid, a derivative of mesoxalic acid (A. 280, 303).
Acetyl Formyl Chloride Oxime is obtained from the product of reaction between
acetic anhydride, formhydroxamic acid and PC16. Silver nitrate converts it
into silver fulminate, silver chloride, and acetic acid (A. 310, 19 ; B. 38, 3858).
Formonitroxime, Methyl Nitrolic Acid, HC<^OH' is PrePared from: (i)
nitromethane (p. 151) and nitrous acid, and (2) isonitrosoacetic acid (p. 250) and
N2C>4. It is decomposed by boiling with water or dilute acids into N2O and
formic acid, and into HNO2 and fulminic acid (p. 250) (B. 40, 418).
Formamidoxime, Methenyl Amidoxime, Isouretine, HC^j,, m.p. 114°, is
isomeric with urea, CO(NH2)2. It results from the evaporation of an alcoholic
solution of hydroxylamine and hydrogen cyanide (Lossen and Schifferdecker,
A. 166, 295).
Methyl Isouretin, NH2CH:NOCH3, m.p. 40°, is prepared from isouretin,
alkali hydroxide, and iodomethane (A. 310, 2).
Formazyl Hydride, HC<^N— NH C H ' m-p> II9-I20°' is obtained from
formazyl carboxylic acid (see Oxalic Acid derivatives).
Derivatives of Orthoformic Acid (p. 236).
Orthoformic Esters are formed (i) when chloroform is heated with sodium
alcoholates in alcoholic solution (Williamson and Kay, A. 92, 346) :
CHCl3+3CH8.ONa==CH(OCH8)8-f3NaCl ;
(2) when formimido-ethers (p. 243) react with alcohols, mixed esters being also
produced (Pinner, B. 16, 1645) :
FORMIC ACID AND ITS DERIVATIVES 245
They are converted by alcoholic alkali hydroxides into alkali formates, and
by glacial acetic acid into acetic esters and ordinary formic esters. Orthoformic
ester is changed by ketones and aldehydes into ortho-ethers, e.g. (CH3)2C(OCaH5)2
(p. 235), and acetal, CH8.CH(OC2H6)2 (p. 205). At the same time, it passes also
into ordinary formic ether (B. 29, 1007). Orthoformic ester, in the presence of
acetic anhydride and aided by heat, combines with acetyl acetone, acetoacetic
ester and malonic ester to yield ethoxymethenyl derivatives (B. 26, 2729).
Orthoformic Methyl Ester, CH(OCH3)3, b.p. 102°. Orthoformic Ethyl Ester,
CH(OC2H6)S, b.p. 146°. Orthoformic Allyl Ester, CH(OC3H6)3, b.p. 196-205°
(B. 12, 115).
Orthothioformlc Ester, CH(SC8H6)3, b.p.10 116°, is prepared from formic acid
ester, or amide, by the action of ethyl mercaptan and hydrochloric acid ; also
from chloroform and sodium mercaptide. It is a colourless oil of unpleasant
odour. It is very stable towards alkalis, but is hydrolized by acids. Permanganate
decomposes it into ethane sulphonic acid and methylene diethyl sulphone (B. 40,
740).
Chloroform, Trichloromethane, CHC13, m.p. —62° (B. 26, 1053),
b.p. 61-5°, D15 = 1-5008, is obtained : (i) by the chlorination of
CH4 or CH3C1 ; (2) by the action of bleaching powder on different
carbon compounds — e.g. ethyl alcohol, acetone, etc. ; (3) by heating
chloral (p. 202) and other aliphatic bodies having a terminal CC13-
group — e.g. trichlor acetic acid and trichlowphenomalic acid (q-v.) —
with aqueous potassium or sodium hydroxide :
CC13.CHO + KOH=CHC13+HC02K.
Chloral. Potassium
Formate.
alcohol and acetone with
lizing and chlorinating substance. The
by slaked lime (Mechanism
of the Reaction : Zincke, B. 26, 501, note). Pure chloroform can be obtained
by decomposing pure chloral with potassium hydroxide ; or by freezing out
crystals of chloroform and then placing this impure substance in a centrifugal
machine (R. Pictet). Perfectly pure chloroform results in the decomposition of
salicylide-chloroform (Anschutz, A. 273, 73).
Historical.* — Chloroform was discovered in 1831 by Liebig and Soubeiran.
It was not until 1835 that Dumas proved conclusively that it contained hydrogen.
In 1847 Simpson, of Edinburgh, introduced chloroform into surgery.
Chloroform is a colourless liquid of an agreeable ethereal odour and
sweetish taste. It is an excellent solvent for iodine and many organic
substances, some of which crystallize out with " chloroform of
crystallization,'' e.g. salicylide-chloroform (see above). Chloroform
seems to enter into a loose combination with ether, which is evidenced
by a rise of temperature when the two liquids are mixed. Inhalation
of its vapours produces anaesthesia. It is uninflammable. It forms
C6C16 when it is conducted through tubes heated to redness.
Reactions. — (i) Chloroform is oxidized by the prolonged action of
sunlight in presence of the oxygen of the air to phosgene (C. 1905,
II. 1623), to prevent which about one per cent, of alcohol is added.
Chromic acid also converts chloroform into this body.
(2) Chlorine converts chloroform into CC14.
(3) When heated with aqueous or alcoholic potassium hydroxide it forms
potassium formate (p. 236) and carbon monoxide. The latter is probably a
* Der Schutz des Chloroforms vor Zersetzung am Licht und sein erstes
Vierteljahrhundert : E. Biltz, 1892. Der Aether gegen den Schmerz. C. Binz,
1896, S. 54.
246 ORGANIC CHEMISTRY
product of reaction with the =OC12 group, which is formed by the expulsion of
HC1 from the chloroform by the action of the alkali. It then unites with the
alkali, whereby the more formic acid is produced the higher the temperature of
reaction (A. 302, 274) :
CHC13+4KOH=HCOOK+3KC1+2H20.
(4) Orthoformic acid ester, CH(O.C2H5)3, is produced when chloroform is
treated with sodium alcoholate.
(5) When heated to 180° with alcoholic ammonia, it forms ammonium cyanide
and chloride. When potassium hydroxide is present, an energetic reaction takes
place at ordinary temperatures. The equation is :
CHC1,+NH3+4KOH==KNC+3KC1+4H20.
(6) Isonitriles (p. 247), having extremely disgusting odours, are formed when
chloroform is heated with primary bases and potassium hydroxide. This reaction
serves both for the detection of chloroform and also of the primary amines.
(7) Chloroform yields an additive product with acetone — e.g. a-hydroxy-
isobutyric acid.
(8) It is converted by sodium acetoacetic ester into m-hydroxyuvitic acid
(Vol. II.).
(9) Aromatic hydroxyaldehydes (Vol. II.) are produced when chloroform is
digested with phenols and sodium hydroxide.
Bromoform, CHBr3, m.p. 7-8°, b.p. 151°, D15 = 2-9, is produced by
the action of bromine and KOH or lime (Lowig, 1832) on alcohol
or acetone ; by electrolysis of a solution of acetone and potassium
bromide (C. 1902, I. 455 ; 1904, II. 301} ; from chloroform and
aluminium bromide (C. 1900, I. 1201 ; 1901, I. 666) ; and also from
tribromopyroracemic acid (q.v.).
lodoform, CHI3, m.p. 120°, is formed when iodine and potassium
hydroxide act on ethyl alcohol, acetone, aldehyde and other
substances containing the methyl group. Pure methyl alcohol, how-
ever does not yield iodoform (B. 13, 1002).
The formation of tri-iodoaldehyde and tri-iodoacetone precedes the
production of the iodoform. These substances are very unstable in
the presence of alkalis. When tri-iodoacetic acid is warmed with acetic
acid, or when it is treated with alkali carbonates, it breaks down into
iodoform and carbon dioxide. lodoform can be obtained by electro-
lysis of an aqueous solution of KI, Na2CO3 and alcohol, or KI and
acetone (C. 1897, H- 695 >* 1898, I. 31 ; 1900, II. 19 ; 1904, 1. 995).
Acetylene-mercury chloride, C2H2.HgCl2, also yields iodoform when
acted on by iodine and alkali (C. 1902, II. 1499).
lodoform crystallizes in brilliant, yellow leaflets, or hexagonal
plates (C. 1899, I- J89 ; 1901, II. 23), soluble in alcohol and ether,
but insoluble in water. Its odour is saffron-like. It evaporates
at medium temperatures and distils in aqueous vapour. Digested
with alcoholic KOH, HI, or potassium arsenite, it passes into meihy-
lene iodide (p. 206) . Light and air decompose iodoform into CO2, CO, I,
and water (C. 1905, II. 1718).
Historical. — lodoform was discovered in 1832 by Serullas. Dumas,
in 1834, proved that it contained hydrogen, and in 1880 it was applied
by Mosetig-Moorhofin Vienna in the treatment of wounds.
Fluoroform, CHF3, is obtained from silver fluoride and chloro-
form, or better, iodoform mixed with sand. It is a gas (B. 23, R. 377.
680 ; C. 1900, I. 886).
FORMIC ACID AND ITS DERIVATIVES 247
Fluorochloroform CHC12F., b.p. 14*5° ; Fluorochlorobromoform, CHClFBr,
b.p. 38° (B. 26, R. 781).
Nitroform, Trinitromethane, CH(NO2)3, has been described already, in connec-
tion with the nitroparaffins (p. 155).
Formyl Trisulphonic Acid, Methine Trisulphonic Acid, CH(SO8H)8, is pro-
duced by the action of sodium sulphite on chloropicrin, CC18(NO2) (q.v.),
and when fuming sulphuric acid acts on calcium methyl sulphonate (p. 210).
The acid is very stable, even in the presence of boiling alkalis (C. 1899, I. 182).
In this connection may be mentioned also dibromonitromethane (p. 151),
nitromethane disulphonic acid (A. 161, 161), and hydroxy "methane disulphonic
acid, CH(OH) (SO3H)a (B. 6, 1032) ; dichloromethane monosulphonic acid, dichloro-
methyl alcohol, are only known as acetic esters.
Carbon Monoxide, Isonitriles or Carbylamines, and Fulminic Acid.
Carbon Monoxide, CO, m.p.100 —207°, b.p.760 —190°, critical
temperature —141°, critical pressure 35 atmospheres, a colourless,
combustible gas, the product of the incomplete combustion of carbon,
has already been discussed in the inorganic section of this book. The
methods for its production and its reactions, which are of importance
in organic chemistry, will again be briefly reviewed. Carbon monoxide
is obtained (i) from formic acid, oxalic acid, a-ketonic acids such as
pyroracemic acid and benzoyl formic acids (Vol. II.) ; (2) from
a-hydroxy-acids such as glycolic acid, lactic acid, malic acid, citric
acid, and mandelic acid (Vol. II.) ; (3) from tertiary carboxylic acids
of the formula R3COOH, such as trimethyl acetic acid (p. 258), tri-
phenylacetic acid (Vol. II.), camphoric acid, cineolic acid (Vol. II.),
from all these by the action of concentrated or fuming sulphuric acid
(comp. B. 39, 51). It is also made from hydrocyanic acid if, in pre-
paring the latter from potassium ferrocyanide, K^Fe^NJ^H^O,
concentrated sulphuric acid be substituted for the more dilute acid ;
in this manner the hydrocyanic acid is changed to formamide, and the
latter immediately breaks down into ammonia and carbon monoxide.
Formamide yields carbon monoxide on the application of heat.
Reactions. — (i) Carbon monoxide and hydrogen exposed to the in-
fluence of electric discharges yield methane (p. 71). Being an un-
saturated compound, carbon monoxide unites (2) with oxygen, giving
a feebly luminous but beautifully blue flame, forming carbon dioxide ;
(3) with sulphur yielding carbon oxysulphide ; and (4) with chlorine,
to form carbon oxy chloride or phosgene. It is rather remarkable that
it also combines directly with certain metals. (5) With potassium it
forms potassium carbon monoxide or potassium hexoxybenzene (q.v.),
C6O6K6 ; (6) with nickel it yields nickel carbonyl, Ni(CO)4, b.p. 43°
(Mond, Quincke, and Langer, B. 23, R. 628 ; C. 1093, I. 1250 ; 1904,
II. mi) ; (7) with iron it yields iron carbonyl Fe(CO)5, b.p. 102°
(C. 1906, 1. 333 ; 1907, 1. 1179). It forms (8) alkali formates with the
alkali hydroxides (p. 236), and with (9) sodium methoxide and
sodium ethoxide it yields sodium acetate and propionate.
Carbon Monosulphide, CS, is not yet known (B. 28, R. 388).
Isonitriles, Isocyanides, or Carbylamines are isomeric with the alkyl
cyanides or the acid nitrites, but are distinguished from these in
that they have their alkyl group joined to nitrogen. The isonitriles
were first prepared in 1866 by Gautier (A. 151, 239) by two methods.
The first consisted in allowing alkyl iodides (i mol.) to act on silver
248 ORGANIC CHEMISTRY
cyanide (p. 242) (2 mols.), whilst in the second method the addition
products of silver cyanide and the alkyl isonitriles were decomposed
by distillation with potassium cyanide :
ia. C,H5I+2AgCN=C2H6NC.AgCN+AgI
ib. C2HBNC.AgCN+KCN=C2H8NC+AgCN.KCN.
Shortly afterwards, A. W. Hofmann (A. 146, 107) found that iso-
nitriles were produced by digesting chloroform and primary amines
with alcoholic potassium hydroxide :
2. C,H5NHt+CHCl,+3KOH=C2H6NC+3KCl+3H2O.
3. The isonitriles are produced as by-products in the preparation
of the nitriles from alkyl iodides or sulphates and potassium cyanide.
Properties. — The carbylamines are colourless liquids which can be distilled,
and possess an exceedingly disgusting odour. They are sparingly soluble in
water, but readily soluble in alcohol and ether.
Reactions. — (i) The isonitriles are characterized by their decomposition
by dilute acids into formic acid and primary amines. This reaction proceeds
readily by the action of dilute acids (HC1), or by heating with water to 180° :
C,H5.NC4-2H2O=CaH6NH2+HCO2H.
Nitriles, on the other hand, by the absorption of water, pass into the ammonium
salts of carboxylic acids :
CtH5CN+2H2O^C2H5COONH4.
It is, therefore, concluded that in the nitriles the alkyl group is in union with
carbon, whilst in the isonitriles it is linked to nitrogen. Three formulas have
been suggested for the isonitriles :
in ii in iv v iv
I. C2H6N=C II. C2H6N=C« III. C2H6N=C.
Nef, who has studied several aromatic isonitriles exhaustively, gives formula I,
the preference (A. 270, 267). (2) The fatty acids convert isonitriles into alkylized
fatty acid amides. (3) The isonitriles, like hydrocyanic acid (p. 240), form
crystalline derivatives with HC1 ; these are probably the hydrochlorides of
alkyl formimide chlorides, 2CH,NC.3HC1 = [CHSN=CHC1]2HC1, which water
decomposes into formic acid and amino- bases. (4) Mercuric oxide changes the
isonitriles into isocyanic ethers, C2H5N=CO, with the separation of mercury,
just as CO, by absorption of oxygen, becomes CO,.
(5) Heat converts the isonitriles into the normal nitriles, RC -N, with
intermediate polymerization products (C. 1907, I. 948).
(6) lodo-alkyls and metallic cyanides unite with the isonitriles to form
double compounds (see above) ; RNC.CNAg can be looked on as being an ester of
a hydrosilvercyanic acid, HAg(CN)2 (C. 1903, II. 827 ; 1907, I. 948).
Methyl Iso cyanide, Methyl Carbylaming, Isoacetonitrile, CH.NC, b.p. 59°.
Ethyl Isocyanide, Ethyl Carbylaming, C2H,NC, b.p. 79°, when heated at from
23-?t. ^5°. ' underS°es atomic rearrangement into propionitrile. It combines
with chlorine to yield ethyl isocyanogen chloride or ethylimidocarbonyl
chloride, a derivative of carbonic acid ; similarly, with bromine to form ethyl
carbylamine bromide (C. 1904, II. 29). With HSS it forms thioformethylimide
(P- 243), and with acetyl chloride it produces ethylimidopyruvyl chloride, a
derivative of pyroracemic acid (A. 280, 291). n-Propyl Isocyanide, b.p. 98°.
n-Butyl Isocyanide, b.p. 119° (C. 1900, II. 366).
Fulminic Acid, Carbyloxime, C=N.OH, is the oxime corresponding
with carbon monoxide, and possesses the properties and characteristics
FORMIC ACID AND ITS DERIVATIVES 249
of a strong acid (R. Scholl, B. 23, 3506 ; Nef, A. 280, 303 ; comp. also,
B. 27, 2817). The fulminates have the same percentage composition
as the salts of cyanic acid, and constitute one of the first examples of
isomeric compounds (Liebig, 1823). Little is known about the free
acid. Its odour is very similar to that of hydrocyanic acid, and' is as
poisonous. The acid is formed when the fulminates are decomposed
by strong acids. It combines quite readily with the latter, — e.g. it
yields formyl chloridoxime with hydrochloric acid (p. 244), which breaks
down very easily with the formation of fulminic acid. The reaction
of the fulminates with hydrochloric acid affords some insight into
the consitution of fulminic acid itself. First, hydrochloric acid unites
directly and salts of formyl chloridoxime arise, from which, by the
absorption of water, formic acid and hydroxylamine are formed :
G=NOAg+HCl =
=HC<^OH+AgCl.
OTT
+2H,O=HCOaH+NH,OH.HCl.
The most important of the salts is mercury fulminate, which is
employed, technically, as a detonating agent.
Historical. — Mercury fulminate was first obtained by Howard, in
1800, by the interaction of a solution of mercuric nitrate and alcohol.
In 1824, Liebig and Guy Lussac showed that silver fulminate
possesses the same percentage composition as silver cyanate, discovered
by Wohler in 1822 — an observation which paved the way for the re-
cognition of the phenomenon of isomerism (p. 25). Kekutt (1856)
considered fulminic acid to be nitro-acetonitrile, NO2CH2CN, an
assumption which could not be sustained, since in 1883 Ehrenberg and
Carstanjer, and also Steiner, found that all the nitrogen in fulminic acid
appears as hydroxylamine when the acid is treated with hydrochloric
acid. Steiner ascribed to fulminic acid the formula C(NOH) : C(NOH).
In 1890, however, R. Scholl put forward the formula C=NOH, indicating
that fulminic acid is the oxime of carbon monoxide ; this ^/completely
substantiated in 1894 by thorough experimental investigation (B.
33, 51).
Mercury Fulminate, (C=N.O)2Hg+JH2O (B. 18, R. 148), is formed
(i) by the action of alcohol (B. 9, 787 ; 19, 993, 1370), acetaldehyde,
dimethyl acetal or malonic acid (C. 1901, II. 404) on a solution
of mercury in excess of nitric acid which contains oxides of nitrogen
(B. 38, 1345) ; (2) by the addition of a solution of sodium nitro-
methane to a mercuric chloride solution :
2CH2=N<°~~Na+HgCla = (C=NO)2Hg+2H20+2NaCl.
There is always produced at the same time a yellow basic salt, (Hg<Q>C-
=NO)gHg, which is the sole product obtained on pouring a solution of mercuric
chloride into a solution of sodium nitromethane. This yellow salt is also very
explosive.
(3) By boiling methyl nitrolic acid (p. 154) with dilute nitric acid
25o ORGANIC CHEMISTRY
in presence of mercury salts. This reaction indicates the course of
the formation of fulminic acid from alcohol (B. 40, 421) :
O HNO« TJ O TJ HNO
CH,.CH,OH
Alcohol.
HON:C-j-HNO2.
Nitrolic Acetic Methyl Nitrolic Fulminic Acid. ,
Acid. Acid.
The formation of fulminic acid from malonic acid (p. 249) proceeds
similarly to the above.
Fulminating mercury crystallizes in shining, white needles, which
are fairly soluble in hot water. It explodes violently on percussion,
and also when acted on by concentrated sulphuric acid. Con-
centrated hydrochloric acid evolves CO2, and yields hydroxylamine
hydrochloride and formic acid, a reaction well adapted for the pre-
paration of hydroxylamine (B. 19, 993).
Chlorine gas decomposes mercury fulminate into mercuric chloride, cyanogen
chloride and CC13NO,. Aqueous ammonia converts it into urea and guanidine
(see acetyl isocyanate). Silver fulminate in benzene solution is converted by
aluminium chloride into j8-benzaldoxime (B. 32, 3492).
Silver Fulminate, C=NOAg, white needles, is prepared after the manner of
the mercury salt, and is even more explosive than the latter. It is also prepared
TT 2AgNO3
from acetofonnyl chloridoxime (p. 244) and AgNO8 • £1>C=NOCOCH8 —
AgCl+CNOAg+HOCOCH8. Potassium chloride precipitates from hot solutions
of silver fulminate one atom of silver as chloride, and the double salt, C2N2O2AgK,
crystallizes from the solution. Nitric acid precipitates from this salt acid
silver fulminate, C2N2O2AgH, a white, insoluble precipitate. On boiling mercury
fulminate with water and copper or zinc, metallic mercury is precipitated and
copper and zinc fulminates (C2NaO2Cu and C2N2O2Zn) are produced.
Sodium fulminate, C=NONa, is obtained when mercury fulminate is digested
with sodium amalgam in alcohol. It crystallizes in fine needles, is explosive and
poisonous. Examined by the freezing-point method, its molecule is found to
be a simple one (B. 38, 1355 ; A. 298, 345). A solution acidified with sulphuric
acid yields to ether a crystalline explosive acid (CNOH)3. Sodium fulminate is
converted to an ester (CNOCH,)S, m.p. 149°, by means of dimethyl sulphate
(C. 1907, I. 27).
In the formation of salts and double salts fulminic acid behaves much like
hydrocyanic acid. This is readily understood if hydrocyanic acid be regarded
as hydrogen isocyanide, C=NH. Sodium ferrocyanide corresponds with sodium
ferrofulminate, (C=NO)6FeNa4+i8H2O, which is produced by bringing together
a solution of sodium fulminate and ferrous sulphate (A. 280, 335). It consists of
yellow needles.
Dibromonitro-aeetonitrile, Dibromoglyoxime Peroxide, CN.CBraNO2, or
BrC=N — O
BrC=aN _ 6 m'^' *5°°' *S Proc*ucec* when bromine acts on mercury fulminate.
This body, when heated with hydrochloric acid, passes into HBr, NHS, NH2OH
and oxalic acid. Aniline probably converts the dibromide into the dioxime of
the oxanilide (C8H6NHC=NOH)2.
Fulminuric Acid, Nitrocyanacetamide, C3N3O3H3=CN.CH(NOa)CONH1, is a
derivative of tartronic acid. Its alkali salts are obtained by boiling mercuric
fulminate with potassium chloride or ammonium chloride and water. The sodium
salt is converted, by a mixture oi sulphuric and nitric acids, into trinitroacetonitrile.
ihe free acid is obtained by decomposing the lead salt with hydrogen sulphide.
it deflagrates at 145°. Especially characteristic is the Cuprammonium salt,
ACETIC ACID AND ITS HOMOLOGUES 251
C,N3O3H3(CuNH8), which consists of glistening purple-coloured prisms. (Comp.
Cyanuric Acid.)
Ethyl iodide converts the silver salt at 80-90° into the Ethyl Ester,
C3H2N3O2(OC3H6), m.p. 133°, which is changed into Desoxyfulminuric Acid,
Cyanisonitroso-acetamide, C3N3H3O2 = CN.C(:NOH)CONH2, m.p. 184° (A. 280,
331), a mesoxalic acid derivative, when boiled with water and alcohol.
ACETIC ACID AND ITS HOMOLOGUES, THE FATTY ACIDS, CnH2n+i.CO2H
We can regard and also designate all the homologues of acetic acid
as mono-, di-, and tri-alkylized acetic acids. Names are then obtained
which as clearly express the constitution of the acids as the carbinol
names show the constitution of the alcohols (p. 101).
The acids of this series are known as fatty acids, because their
higher members occur in the natural fats. The latter are esters of the
fatty acids, with glycerol, a trihydric alcohol. On boiling them with
potassium or sodium hydroxide, alkali salts (soaps) of the fatty acids
are formed, and from these the mineral acids liberate the fatty acids.
Hence, the process of converting a compound ester into an acid and an
alcohol has been termed saponffication, and this term has been applied
to the conversion of other derivatives of the acids into the acids
themselves — ^.g.the conversion of nitrilesinto the corresponding acids.*
The lower acids (with exception of the first members) are oils ; the
higher, commencing with capric acid, are solids at ordinary tempera-
tures. The first can be distilled without decomposition ; the latter
are partially decomposed, and can only be distilled without alteration
under reduced pressure. Only the first members are volatile in steam.
Acids of similar structure show an increase in their boiling points of
about 19° for each increase in CH2. It may be remarked that the melt-
ing points are higher in acids of normal structure, containing an even
number of carbon atoms, than in the case of those having an odd
number of carbon atoms. The dibasic acids exhibit the same cha-
racteristic. As the oxygen content diminishes, the specific gravities
of the acids grow successively less, and the acids themselves at the same
time approach the hydrocarbons in character. The lower members
are readily soluble in water, but the solubility regularly diminishes with
increasing molecular weight. All dissolve readily in alcohol, and very
easily in ether. Their solutions redden blue litmus. The acidity
diminishes with increasing molecular weight ; this is very clearly
evidenced by the diminution of the heat of neutralization and the
initial velocity in the etherification of the acids.
The most important general methods of preparation of the
monobasic acids are :
(i) Oxidation of the primary alcohols and aldehydes :
CH8.CH2OH- ^> {cH3.CH<°g} -1^ CH3C<g - %- CH3.C<°H
Ethyl Alcohol. Aldehyde. Acetic Acid.
The oxidizing agents most usually employed are chromic acid and perman-
ganate (C. 1907, I. 1179).
* The term hydrolysis is more strictly accurate. — TR.
252 ORGANIC CHEMISTRY
In the case of normal primary alcohols with high molecular weight the con-
version into the corresponding acids is effected by heating with soda-lime :
C18H81CH2OH+NaOH=C16H31.C02Na-}-2H2.
Cetyl Alcohol. Sodium Palmitate.
(2) By the addition of hydrogen to the unsaturated monocarboxylic acids :
CH2 =CH.CO2H +2H =CH3.CH2.COaH.
Acrylic Acid. Propionic Acid.
(3) By the reduction of hydroxy-acids at raised temperatures by means
of hydriodic acid :
CH,.CH(OH)COaH+2HI=CH,.CHa.C01H+H2O+It.
Or, halogen substituted acids may be reduced by means of sodium amalgam.
Many nucleus-synthetic methods are known for the formation of
derivatives of the acids, which can easily be changed to the latter.
These methods are important in the building-up of the acids.
(4) Synthesis of the Acid Nitrites. — The alkyl cyanides, called also
the fatty acid nitrites, are produced by the interaction of potassium
cyanide and alkylogensor the alkali salts of the alkyl sulphuric acids.
When the alkyl cyanides or fatty acid nitriles are heated with alkalis
or dilute mineral acids the cyanogen group is transformed into the
carboxyl group, whilst the nitrogen is changed to ammonia. In this
manner formic acid is produced from hydrocyanic acid (p. 236) :
CHt.CN+2H2O+HCl=CH,.CO2H+NH4Cl
CH,.CN+H2O+KOH=CH8.CO2K4-NH,.
This method makes the synthesis of acids from alcohols possible.
The change of the nitriles to acids is, in many instances, best carried out
by digesting the former with sulphuric acid (diluted with an equal volume of
water) ; the fatty acid will then appear as an oil upon the surface of the solution
(B. 10, 262).
The conversion of the nitriles directly into esters of the acids may be effected
by dissolving them in alcohol and passing hydrochloric acid gas into the solution,
or by warming it with sulphuric acid (B. 9, 1590).
(5) The action of carbon monoxide on the sodium alcoholates heated to
160-200° only proceeds smoothly and easily in the case of sodium methoxide
and ethoxide (A. 202, 294 ; C. 1903, II. 933) :
C2H5.ONa+CO = C2H8.C02.Na.
Sodium Etboxide. Sodium Propionate.
Similarly, carbon monoxide and sodium hydroxide yield formic acid (p. 236).
(6a) The action of carbon dioxide on sodium alkyls (A. Ill, 234) is only
applicable with sodium methyl and sodium ethyl (p. 184). It may be compared
with that in which formic acid is produced by the action of moist carbon dioxide
on potassium (potassium hydride) :
C2H6.Na+CO2=C2H6.CO2Na.
(66) By the action of carbon dioxide on an ethereal solution of an alkyl
magnesium halide, and the decomposition of the resulting magnesium compound
by ice and sulphuric acid (C. 1901, II. 622 ; B. 35, 2519) :
CO, H2o
CH,MgBr > CH3C02MgBr > CH3COOH.
(7) By the action of phosgene gas, COC12, on the zinc alkyls. Acid chlorides
are first formed, and subsequently yield acids when treated with water :
Zn(CH,)a+2COCl2=2CH8.COCl+ZnCl2, and
Acetyl Chloride.
CH,.COC1+H20=CH8.CO.OH+HC1.
Acetic Acid,
ACETIC ACID AND ITS HOMOLOGUES 253
(8) Electro-syntheses of the esters of monocar boxy lie acids occur upon
electrolyzing mixtures of the salts of fatty acids and the mono-esters of dicar-
boxylic acids. Butyric ester, for example, is obtained from potassium acetate
and potassium ethyl succinate (B. 28, 2427) :
CH3'CO.
CHaJCO,.
CH2.CO2C2H5 CHa-COa.CaH6
K , HOH CH, , C02 , KOH , H
+ =» | + + T !•
K HOH CH, CO, KOH H
The following methods of formation are based upon the breaking-
down of long carbon chains :
(9) The decomposition of ketones by oxidation with potassium
dichromate and sulphuric acid (p. 219) :
CH3[CH2]14.CO.CH3 > CH3[CH2]18COaH-f CH8.C02H
Pentadecyl Methyl Ketone from Pentadecyclic Acid. Acetic Acid.
Palmitic Acid.
By the action, also, of chlorine and alkali, the alkyl methyl ketones
can be made to yield chiefly carboxylic acids, the change being due to
the separation of the CH3 group in the form of chloroform and the
replacement of it by the hydroxyl group.
(10) Decomposition of unsaturated acids by fusion with potassium
hydroxide :
KOH
CH3CH : C(CH,)COaK > CH3CO2K and CH8CHa.CO2K.
Potassium Angelicate. Potassium Potassium Propionate.
Acetate.
(n) Decomposition of acetoacetic ester, as well as mono- and dial-
kyl acetoacetic esters, by concentrated alcoholic potassium hydroxide :
CH3CO.CH2COaCaH6+2KOH=CHsCOaK+CH8COaK+CaH6OH
Acetoacetic Ester.
CH8CO.CH(R)COaCaH6+2KOH=CH3COaK4-CH2(R)CO2K+C2H5.OH
CH8CO.C(R)aCOaCaH6+2KOH=CH,COaK-f-CH(R)aCOaK+CaHe.OH.
The mono- and di-alkyl acetoacetic esters are decomposed, by
boiling sodium alcoholate solution, into mono- and di-alkyl acetic ester.
(12) Decomposition of ketoxime carboxylic acids, after internal re-
arrangement into acid amides. This reaction is valuable in deter-
mining the constitution of the olefine carboxylic acids, from which the
ketoxime carboxylic acids can be prepared. (Comp. oleic acid,
p. 300.)
(13) Decomposition of dicarboxylic acids, in which the two carboxyl
groups are in union with the same carbon atom. On the application
of heat, these lose carbon dioxide :
CHa\p/~v TT ^ CH3.COaH -|-COj
Malonic Acid.
^2S > CHa(R)COaH+CO,
c(R)*<COaH > CH(R)aCOaH+COa.
The acids produced by the methods n and 13 can be regarded as directly
derived from acetic acid, CH8.COOH, in which i or aH atoms of the CHs-group
254 ORGANIC CHEMISTRY
«
are replaced by alky Is ; hence the designations methyl- and dimethyl-acetic acid,
etc.:
CHa.CH, CH2.C,H6 CH(CH,)t
COOH COOH COOH
Methyl Acetic Acid or Ethyl Acetic Acid or Dimethyl Acetic Acid or
Propionic Acid. Butyric Acid. Isobutyric Acid.
To comprehend fully the importance of these two methods of
formation the following facts may be stated here, though they are out
of their pre-arranged sequence.
Acetic ester is the parent substance for the production of aceto-
acetic ester, and chloracetic ester for that of malonic ester. Aceto-
acetic ester, CH3CO.CH2CO.OC2H5, and malonic ester, CH2(COOC2H5)2,
contain a CH2-group, in combination with two CO-groups. One
hydrogen atom in a CH2-group thus situated may be replaced by sodium,
and the latter, through the agency of an alkyl iodide, by an alkyl group.
In this manner monoalkyl acetoacetic esters, CH3CH.CHRCO.OC2H5, and
monoalkyl malonic esters, CHR(COOC2H5)2, are obtained. Further,
in these monoalkylic derivatives the second hydrogen atom of the
CH2-group may be substituted by sodium, and this, in turn, may be
replaced by a similar or a different alcohol radical, through the action
of an alkylogen : the products are then dialkyl acetoacetic esters, CH3-
CO.C(R)2COOC2H5, and dialkyl malonic esters, C(R)2(COOC2H5)2.
The ease with which all of the reactions involved in the formation of
the alkyl malonic and acetoacetic esters are carried out render these
bodies very convenient material for the production of a nucleus synthesis
of mono- and dialkyl acetic acids. The breaking-down of malonic
acid and the alkyl malonic acids possesses this advantage, that it pro-
ceeds in one direction only, whereas the alkyl acetoacetic esters undergo
a ketone decomposition simultaneously with the acid decomposition,
with the separation of the carboxyl group (p. 218).
Isomerism. — Every monocarboxylic acid corresponds with a primary
alcohol. Hence the number of isomeric monocarboxylic acids of
definite carbon content is, as in the instance of the aldehydes, equal
to that of the possible primary alcohols (p. 103), possessing a like
quantity of carbon. The isomerism is dependent upon the isomerisms
of the hydrocarbon radicals in union with the carboxyl group.
There are no possible isomers of the first three members of the
series CnH2nO2 :
H.C02H CH3.CO?H CaH5.C02H
Formic Acid. Acetic Acid. Propionic Acid.
Two structural isomers are possible for the fourth member,
C4H802 :
CH3.CH2.CH2.CO2H and (CHS)2.CH.CO2H.
Propyl Carboxylic Acid Isopropyl Carboxylic Acid.
Butyric Acid. Isobutyric Acid.
Four isomers are possible with the fifth member, C5H1002=
C4H9.CO2H, inasmuch as there are four butyl, C4H9, groups, etc.
Reactions. — A concise review of their many derivatives was given
in the introduction to the monocarboxylic acids, which were obtainable
in part from the acids, or directly from their salts. Their most im-
portant reactions follow :
ACETIC ACID AND ITS HOMOLOGUES 255
(1) Acids and alcohols yield esters in the presence of hydrochloric
or sulphuric acid (p. 263).
(2) Salts and alkylogens, or alkyl sulphates, yield esters.
(3) Acids or salts, when acted on by the chlorides of phosphorus,
yield acid chlorides (p. 269) and acid anhydrides (p. 271).
(4) The ammonium salts of the acids lose water and become
acid amides (p. 274) and acid nitrites (p. 278).
(5) The halogens produce substitution products.
(6) The fatty acids are very stable in the presence of oxidizing
agents, and are only attacked very slowly. Those acids, containing a
tertiary group, yield nitro-derivatives (B. 15, 2318 ; 32, 3661) when
acted on by nitric acid.
In discussing the paraffins, their alcohols, aldehydes and ketones,
methods of producing these bodies were described, which were based
upon reactions of the fatty acids, their salts or their immediate
derivatives. These may be summarized here :
(1) Paraffins (p. 74) result from the reduction of higher fatty acids
by hydriodic acid.
(2) Paraffins (p. 74) are produced when the calcium salts of the
fatty acids are distilled with soda-lime.
(3) Paraffins, together with CO2, alcohols, and other products
(p. 73), result from the electrolysis of concentrated solutions of the
potassium salts of the fatty acids.
(4) Acid chlorides and anhydrides, when reduced, yield aldehydes
(p. 191) and primary alcohols (p. 103).
(5) Acid chlorides, esters, amides, and nitriles reacting with zinc
alkyls or magnesium alkyl halides yield ketones (p. 217) and tertiary
alcohols (p. 105).
(6) By the interaction of iodine and the silver salts of fatty acids, esters of
the next lower alcohol are formed (comp. p. 263).
(7) When the calcium salts are distilled with calcium formate,
aldehydes are produced (p. 190).
(8) Simple and mixed ketones (p. 190) are formed when a single
calcium salt or an equimolecular mixture of two different calcium
salts are distilled respectively.
(9) The reduction of acid nitriles yields primary amines ; these,
are converted into the corresponding alcohols by nitrous acid.
(10) Acid amides, when acted on by bromine and sodium hy-
droxide, lose CO as carbon dioxide and pass into the next lower
series of primary amines. This reaction can therefore be employed for
proceeding step by step down the series of fatty acids (p. 263). The
azides of the acids behave similarly when acted on by water or alcohol.
The constitution of the fatty acids follows from their production
from bodies of known constitution and their conversion into the same.
Acetic Acid [Ethane Acid], CH3.COOH (Acidum aceticum), m.p.
16*7°, b.p. 118° D20=i"0497, formed by the spontaneous souring of
alcoholic liquids, is the acid which has been longest known. Vinegar
and the term " acid " were designated, for example, by the Romans
by closely related words. Wood vinegar first became known in the
middle ages.
256 ORGANIC CHEMISTRY
Acetic acid is found in the vegetable kingdom both free and in the form of
salts and esters. Thus, it was mentioned under n-hexyl and n-octyl alcohols
that they occurred in the form of their acetic esters in the ethereal oil of the seed
of Heracleum giganteum and in the fruit of Heracleum sphondylium. The officinal,
concentrated acid, as well as the thirty per cent, aqueous solution of the acid,
are applied medicinally.
Acetic acid is produced in the decay of many organic substances
and in the dry distillation of wood, sugar, tartaric acid, and other
compounds ; also in the oxidation of numerous carbon derivatives, as
it is very stable towards oxidants.
The methods of forming acetic acid, which have any particular theoretical
value, have already been discussed under the general methods for the production
of fatty acids (p. 251) ; therefore they will be but briefly noticed here :
(1) The oxidation of ethyl alcohol and acetaldehyde.
(2) The reduction of hydroxyacetic acid or glycollic acid, CH2(OH).CO2H,
and the reduction of chlorinated acetic acids — e.g. trichloracetic acid, CC13.CO2H.
Synthetically : (3) From methyl cyanide or acetonitrile.
(4) From sodium methoxide and carbon monoxide.
(5) From sodium methyl or magnesium methyl iodide and carbon dioxide.
(6) From phosgene and zinc methyl.
By decomposition : (7) By the oxidation of acetone and many mixed methyl
ketones.
(8) By the decomposition of many unsaturated acids of the oleic series when
fused with potassium hydroxide.
(9) From acetoacetic ester by means of alcoholic potassium hydroxide.
(10) By heating malonic acid.
Finally, a rather remarkable synthesis consists in allowing air and potassium
hydroxide to act on acetylene in diffused daylight (Berthelot, 1870) :
CH=CH+H2O+O=CHS.COOH.
Historical. — At the close of the eighteenth century Lavoisier recognized the
fact that air was necessary for the conversion of alcohol into acetic acid, and
that its volume was correspondingly diminished during the process. In 1830
Dumas converted the acid, by means of chlorine, into trichloracetic acid ; whilst
the reconversion of the latter into the parent acid, by potassium amalgam and
water, was demonstrated by Melsens in 1842. But when, in 1843, Kolbe succeeded
in producing trichloracetic acid (p. 287) from its elements, the first synthesis of
acetic acid was accomplished.
Acetic acid is produced (i) by the oxidation of ethyl alcohol and
liquids containing this alcohol. It is customary, depending upon
their origin, to distinguish wine vinegar, fruit vinegar, and malt vinegar.
(i) The Quick-vinegar Process (Schiitzenbach, 1823).— The acetic fermenta-
tion of alcoholic liquids consists in the transference of the oxygen of the air
to the alcohol (Pasteur). This is effected by the acetic ferment, the " mother
of vinegar," — Mycoderma aceti, Micrococcus aceti, or Bacterium aceti* — the
germs of which are always present in the air. In this process, by an enlarge-
ment of the contact surface of the alcoholic liquid with the air, there ensues an
accelerated oxidation. Large wooden tubs are filled with shavings previously
moistened with vinegar, upon which diluted (ten per cent.) alcoholic solutions
are poured. The lower part of the tub, exposed in a warm room (25-30°), is
provided with a sieve-like bottom, and all about it are holes permitting the
entrance of air to the interior. The liquid collecting on the bottom is run through
the same process two or three times, to ensure the conversion of all the alcohol
into acetic acid.
* Vorlesungen uber Bacterien von A. de Bary, 1887. Die Gahrungschemie
von Adolf Mayer, 1895.
ACETIC ACID AND ITS HOMOLOGUES 257
(2) Wood Vinegar Process. — Considerable quantities of acetic acid are also
obtained by the dry distillation of wood in cast-iron retorts, a process already
referred to when discussing methyl alcohol (p. 109). The aqueous distillate,
consisting of acetic acid, wood spirit, acetone, and empyreumatic oils, is neutralized
with soda, evaporated to dryness, and the residual sodium salt heated to 230-
250°. In this manner, the greater portion of the various organic admixture
is destroyed, sodium acetate remaining unaltered. The salt purified in this
way is distilled with sulphuric acid, when acetic acid is set free and purified by
further distillation over potassium chromate.
Properties. — Anhydrous acetic acid at low temperatures consists of
a leafy, crystalline mass — glacial acetic acid — which, on melting, forms
a liquid of sharp and penetrating odour. It mixes with water in all
proportions ; at first a contraction ensues, consequently the specific
gravity increases until the composition of the solution corresponds with
the hydrate, C2H4O2+H2O (=CH3.C(OH)3), D15=ro754 (77-80 per
cent.). On further dilution, the specific gravity becomes less, until a
43 per cent, solution possesses about the same specific gravity as
anhydrous acetic acid. Ordinary vinegar contains about 5 per cent,
of acetic acid. Acetic acid is an excellent solvent for many carbon
compounds. Even the halogen acids dissolve readily in glacial acetic
acid (B. 11, 1221). Pure acetic acid should not decolorize a drop of
potassium permanganate solution. It may be detected by conversion
into volatile acetic ether when heated with alcohol and sulphuric acid
(p. 267), or by the formation of cacodyl oxide (p. 176).
Acetates. — The acid combines with one equivalent of the bases,
forming readily soluble, crystalline salts. It also forms basic salts
with iron, aluminium, lead and copper ; these are sparingly soluble in
water. The alkali salts have the additional property of combining
with a molecule of acetic acid, yielding acid salts, such as C2H3O2K-t-
C2H4O2, acid potassium acetate.
Potassium Acetate, C2H3O2K, deliquesces in the air and dissolves readily
in alcohol. The acid salt, CaH3KO2.C2H4O2, m.p. 148°, crystallizes out in pearly
leaflets. The salt, C2H3OaK+2CaH4O2, m.p. 112°, is decomposed at 170° into
acetic acid and the neutral salt.
Sodium Acetate, C2H8O2Na+3HaO, crystallizes in large, rhombic prisms,
which effloresce on exposure. When heated, the anhydrous salt remains un-
changed at 310°.
Ammonium Acetate, C2H3O2NH4, is a crystalline mass. Heat applied to
the dry salt converts it into water and acetamide (C. 1903, I. 386). Calcium
Acetate, (C2H3O2)2Ca+HaO, and Barium Acetate, (C2H3O2)2Ba+H2O, dissolve
readily in water.
Ferrous Acetate, (C2H3O2)aFe, readily oxidizes in aqueous solution to insoluble
basic ferric acetate. Ferric Acetate, (C2H3O2)6Fe2, is not crystallizable. On
boiling, basic ferric acetate is precipitated. Aluminium Acetate behaves similarly.
Both salts are employed as mordants in dyeing, as they are capable of uniting
with the cotton fibre. The basic salts produced on the application of heat are
capable of retaining dyes.
Normal Lead Acetate, (CaH8O2)2Pb-f 3H2O, is obtained by dissolving litharge
in acetic acid. The salt forms brilliant four-sided prisms, which effloresce on
exposure. It possesses a sweet taste (hence called sugar of lead), and is poisonous.
If an aqueous solution of lead acetate be boiled with litharge, basic lead acetates,
of varying lead content, e.g. C2H3O2PbOH and C2H3O2Pb.O.Pb.O.Pb.C2H3O2,
are produced. These solutions react alkaline, and absorb carbon dioxide from
the air, depositing basic carbonates oi lead — white lead.
Lead Tetr a- acetate, (CaH3Oa)4Pb is obtained when minium is dissolved in
VOL. I. S
258 ORGANIC CHEMISTRY
hot glacial acetic acid. From the filtrate colourless monoclinic prisms separate ;
cUo easily soluble in water. Basic copper
saltslfccur m ^commSc^unSer tht name of Tigris. They are obtained by dis-
in acetic acid in presence of air. The double salt of acetate
or leaflets. The salt
is soluble in 98 parts water at 14° C.
The decompositions of the acetates have already been considered ;
summarized they are :
(1) Potassium acetate, when electrolyzed, yields ethane (p. 73).
(2) Sodium acetate, heated with soda-lime, yields methane (p. 72).
(3) Potassium acetate and arsenious oxide, on the application of
heat, yield cacodylic oxide (p. 177).
(4) Ammonium acetate loses water when heated, with the formation
of acetamide (p. 277).
(5) Calcium acetate is decomposed by heat into acetone (p. 190, 222).
(6) Calcium acetate and calcium formate, heated together, yield
aldehyde (p. 190).
(7) Calcium acetate and the calcium salts of higher fatty acids
when heated yield mixed methyl alkyl ketones (p. 190).
PROPIONIC ACID. BUTYRIC ACIDS. VALERIC ACIDS
The following table contains the melting points (B. 29, R. 344),
the boiling points, and the specific gravities of the normal acids and
their isomers : —
Name.
Formula.
M. P.
B. P.
Specific
Gravity.
Propionic Acid, Methyl Ace-
CH8CHj— COaH
—36-5°
140°
0-9920 (18°)
n-Butyric Acid, Ethyl Acetic
Acid . . ....
CH8(CHa)jCO2H
163°
O*Q^8*7 (I2.O®\
Isobutyric Acid, Dimethyl
Acetic Acid ....
CH8
-79°
155°
0-9490 (20°)
n-Valeric Acid, n-Propyl
Acetic Acid ....
CH8(CHa)8C02H
-59°
186°
0-9568 (o°)
Isovaleric Acid, Isopropyl
Acetic Acid ....
C8H7CHa— C02H
— 51"
174°
0-9470 (o°)
Methyl Ethyl Acetic Acid .
£**| >CH— CO2H
—
175°
0-9410 (21°)
Trimethyl Acetic Acid,
» 6
Pivallic Acid ....
(CH8)8C.COaH
+35°
163°
MBM
Propionic MIA, Methyl Acetic Acid [Propane Acid], CH8.CHf.CO2H, may be
prepared by the methods in general use in making fatty acids ; (i ) by the oxida-
tion of n-propyl alcohol and propyl aldehyde with chromic acid ; (2) by reduction
of acrylic acid (p. 294) and propargylic acid (p. 303) ; (3) by reduction of lactic acid,
CH8.CH(OH).CO2H, and glyceric acid, CH2OH.CHOH.CO,H ; (4) (synthetically)
from ethyl alcohol by its conversion, through ethyl iodide, into ethyl cyanide or
PROPIONIC ACID. BUTYRIC ACIDS. VALERIC ACIDS 259
propionitrile ; (5) from sodium ethoxide and carbon monoxide ; (6) from sodium
ethyl or magnesium ethyl bromide and carbon dioxide ; (7) (by decomposition)
in the oxidation of methyl ethyl, methyl propyl and diethyl ketone ; (8) by
the action of alcoholic potassium hydroxide on methyl acetoacetic ester with
the simultaneous production of ethyl methyl ketone ; (9) from methyl malonic
acid or isosuccinic acid by the application of heat.
Its formation from malate and lactate of calcium by fermentation is worthy
of note (B. 12, 479 ; 17, 1190). Gottlieb first discovered propionic acid in 1847,
when he fused sucrose with potassium hydroxide. Dumas gave the acid its
name, derived from irpwros, the first, irlwv, fat, because when treated in aqueous
solution with calcium chloride it separated as an oil. It is the first acid which
in its behaviour approaches the higher fatty acids.
The barium salt, (C3H6O2)2Ba+H2O, crystallizes in rhombic prisms: silver
salt, C8H6O2Ag, dissolves sparingly in water.
Butyric Acids, C4H8O2.
Two isomeric acids are possible :
(1) Normal Butyric Acid, Ethyl Acetic Acid [Butane Acid], butyric
acid of fermentation, occurs free and also as the glycerol ester in
the vegetable and animal kingdoms, especially in the butter of cows
(to the amount of about five per cent., together with glycerides of
palmitic and oleic acids), in which Chevreul found it, in the course
of his classic investigations upon the fats. It exists as hexyl ester in
the oil of Heracleum giganteum, and as octyl ester in Pastinaca saliva.
It has been observed free in the perspiration and in the body fluids.
It may be obtained by the usual methods employed for the prepara-
tion of fatty acids, and is produced in the butyric fermentation of
sugar, starch and lactic acid, and in the decay and oxidation of
proteins.
Ordinarily the acid is obtained by the fermentation of sugar or starch, induced
by the previous addition of decaying substances, e.g. cheese, in the presence of
calcium or zinc carbonate, which are intended to neutralize the acids as they form.
According to Fitz, the butyric fermentation of glycerol or starch is most advan-
tageously evoked by the direct addition of schizomycetes, especially Bacillus
subtilis and Bacillus boocopricus (B. 11, 49, 53 ; 29, 2726).
Butyric acid is a thick, rancid-smelling liquid, which solidifies when
cooled. It dissolves readily in water and alcohol, and may be thrown
out of solution by salts.
The calcium salt, (C4H7O2)2Ca+H2O (A. 213, 67), yields brilliant leaflets,
and is less soluble in hot than in cold water (in 3*5 parts at 15°) ; therefore the
latter grows turbid on warming (B. 30, 2956).
(2) Isobutyric Acid, Dimethyl Acetic Acid [Methylpropane Acid],
(CH3)2.CH.CO2H, is found free in St. John's Bread, the pod of the
carob- or locust-tree, Ceratonia siliqua, as octyl ester in the oil of
Pastinaca sativa, and as ethyl ester in crbton oil. It is prepared
according to the general methods (p. 251). Concentrated nitric acid
converts it into dinitropropane (p. 155) ; and potassium perman-
ganate oxidizes it to a-hydroxyisobutyric acid.
Isobutyric acid bears great similarity to normal butyric acid, but is riot
miscible with water.
The calcium salt, (C4HTO2),Ca+5H2O, dissolves more readily in hot than
in cold water.
26o ORGANIC CHEMISTRY
Valeric Acids, C5H10O2. There are four possible isomers (comp.
table, p. 258) :
(1) Normal Valeric Acid, n-Propylacetic Acid [Pentane Acid],CHs.(CHa),.-
CO,H, is formed according to the usual methods (p. 251, et seq.).
Ordinary valeric acid occurs free, and as esters in the animal and
vegetable kingdoms, chiefly in the small valerian root (Valeriana
officinalis), and in the root of Angelica Archangelica, from which it
may be isolated by boiling with water or a soda solution. It is a
mixture of isovaleric acid with the optically active methyl ethyl acetic
acid, and is therefore also active. A similar artificial mixture may be
obtained by oxidizing the amyl alcohol of fermentation (p. 120) with
chromic acid mixture. Valeric acid combines with water and yields
a hydrate, C5H1002+H2O, soluble in 26-5 parts of water at 15°.
(2) Isovaleric Acid, Isopropyl Acetic Acid [3-Methyl-butane Acid],
(CH3)2.CH.CH2.CO2H, may be synthetically obtained by some of the
methods described on p. 252. It is an oily liquid with an odour re-
sembling that of valerian.
Potassium permanganate oxidizes isovaleric acid to jS-hydroxyisovaleric acid,
(CH,),.C(OH).CH2.CO2H. Concentrated nitric acid attacks, in addition, the CH-
group, forming methyl hydroxysuccinic acid, fi-nitroisovalcric acid, (CH8)a.C(NO2).-
CH2.CO2H, and p-dinitropropane, (CH,)2C(NOa)a (B. 15, 2324). (Conip. the
behaviour of isobutyric acid.)
The isovalerates generally have a greasy feel. When thrown in small pieces
upon water they have a rotary motion, dissolving at the same time ; barium salt,
(C6HtO2)aBa; calcium salt, (C5H8O,)2Ca+3HaO, forms stable, readily soluble
needles; zinc salt, (C6H,Oa)2Zn-|-2H2O, crystallizes in large, brilliant leaflets;
when the solution is boiled a basic salt separates.
PTT *
(3) Methyl Ethyl Acetic Acid, [2-Methyl-butane Acid], c™8>CH.COaH, con-
tains an asymmetric carbon atom, and, like its corresponding alcohol (p. 120),
may exist in two optically active and one optically inactive modification. The
optically inactive form has been synthesized, and has also been resolved by
means of its brucine salts into its optically active components. The /-salt
dissolves with difficulty. The specific rotatory power of the optically active
methyl ethyl acetic acid is [a]0 =±17° 85' (B. 32, 1089).
Calcium salt, (C5HtOa)2Ca+5H2O.
An optically active methyl ethyl acztic acid is present in valerian and angelica
roots together with isopropyl acetic acid, as already mentioned, and also in
the products of oxidation of fermentation amyl alcohol (A. 204, 159). Pure
d-methyl ethyl acetic acid is prepared by the oxidation of pure /-amyl alcohol
(p. 120) (B. 37, 1045) ; and has been found in the break-down products of
convolvulin (Vol. II.).
(4) Trimethyl Acetic Acid, Pivalic Acid, [Dimethyl -propane Acid], (CH3)3-
C.CO2H), is formed from tertiary butyl iodide, (CH3)3C1 (p. 134), by means of
the cyanide ; also by the oxidation of pinacoline (p. 224). The acid is soluble in
40 parts H2O at 20°, and has an odour resembling that of acetic acid.
Barium salt, (C6HtO2)aBa+5H2O ; calcium salt, (C5H,O2)aCa+5H2O (C.
1898, I. 202).
HIGHER FATTY ACIDS
The subjoined table contains the melting and boiling points of the
higher fatty acids, beginning with those containing six carbon atoms.
The boiling points enclosed in parentheses were determined under
100 mm. pressure :
HIGHER FATTY ACIDS
261
Name.
Formula.
M. P.
B. P.
n-Hexoic Acid, n-Caproic Acid .
~ Isobutyl Acetic Acid (B. 27,
R igi)
CH3.(CH2)4COaH
(CH a) 2CH fCH .1 XO ,H
+ 3°
205°
108°
sec.-Butyl Acetic Acid (B. 26,
R. on)
(C2H6)(CH3)CHCH2CO2H
174°
Diethyl Acetic Acid . . .
Methyl n-Propyl Acetic Acid .
Methyl Isopropyl Acetic Acid .
Dimethyl Ethyl Acetic Acid .
n-Heptoic Acid, (Enanthylic
Acid
£»^5>CHC02H
}c4;>CHC°*H
(SP£)2>CCO,H
^2^6
CHo(CH«)RCO,H
-14°
— 10-5°
190°
193°
191°
187°
223°
Methyl n-Butyl Acetic Acid .
Ethyl n-Propyl Acetic Acid .
Methyl Diethyl Acetic Acid .
n-Octoic Acid, Caprylic Acid
n-Nonoic Acid, Pelargonic Acid .
c<;H3>CHCOaH
^•>CHC01H
ecjS?*30*
CH3(CH2)6C02H
CH3(CH2)7C02H
CHJCHo)flCO,H
16-5°
12-5°
31-4°
210°
209°
208°
237°
254o°
270
CH,(CH,)«CO2H
28-5°
(2I2'«>0)
CH,(CH2)10CO2H
43-5°
(225°)
CHg^H-jJnCOjH
40-5°
(236°)
n-Myristic Acid
CH.(CHo),,CO.H
53'S°
(22C-V)
n-Pentadecatoic Acid (B. 27,
R 191)
CH,fCHo^«CO,H
51°
(2600)
Palmitic Acid
CH,(CH»)nCO,H
62°
(278-5°)
Margaric Acid
Stearic Acid
Di-n-octyl Acetic Acid .
CH8(CH2)16C02H
CH3(CH2)16C02H
[CH3(CH2)7]2CHC02H
C.ntL.O,
59*9°
69-2°
38-5°
75°
(280-5°)
(291°)
C-,H,4O.
*3°
Co.Hr.Oo OT Co^Hr.O,
7«°
Melissic Acid «...
90°
The normal fatty acids in the preceding list, having an even number
of carbon atoms, occur almost exclusively in the natural oils and fats,
which are chiefly glycerides of these acids. Palmitic and stearic acids
possess great technical importance.
Caproic Acid, n-Hexoic Acid, CH3(CH2)4CO2H, occurs in the
form of its glycerol ester in cow's butter, goat butter, and in coconut
oil. It is produced, together with butyric acid, in the butyric fermen-
tation.
(Enanthylic Acid, n-Heptoic Acid, CH3(CH2)5CO2H, can easily be
obtained as an oxidation product of cenanthol (p. 201).
Caprylic Acid, n-OctoicAcid, CH3(CH2)6CO2H, occurs as its glycerol
ester in goat butter and in many fats and oils ; also in the fusel-oil of
wine.
Pelargonic Acid, n-Nonoic acid, CH3(CH2)7CO2H, is present in the leaves of
Pelargonium roseum, and is prepared by the oxidation of oleic acid and oil
of rue (methyl n-nonyl ketone, p. 224). It may also be obtained by the fusiou
of undecylenic acid with potassium hydroxide.
262 ORGANIC CHEMISTRY
Capric Acid, n-Decylic Acid, CH3(CH2)8CO2H, is present in butter, goat
butter, in coconut oil and in many fats, and as its amyl ester in fusel oil.
the first normal acid that is solid at the ordinary temperature.
n-Undecylic Acid, CH3(CH2)9CO2H, is obtained by reduction of undecylemc
acid from castor oil.
Laurie Acid, n-Dodecylic Acid, CH3(CH2)10CO2H, occurs as its glycerol ester
in the fruit of laurels, Laurus nobilis, in coconut oil (C. 1904, I. 259), and in
pichurim beans. It is found as its cetyl ester in spermaceti.
Myristic Acid, n-Tetradecylic Acid, CH3.(CH2)12CO2H, occurs in muscat
butter (from Myristica moschata), in spermaceti and coconut, in myrisiin
(B. 18, 2011 ; 19, 1435), in earth-nuts (B. 22, 1743), in ox-bile (B. 25, 1829),
and as free acid, as well as its methyl ester, in iris root (B. 26, 2677).
Palmitic Aci&,n-HexadecylicAcid, CHgfCHg^COsH.— The glycerol
ester of this acid and that of stearic acid and oleic acic are the
principal constituents of solid animal fats. Palmitic acid occurs
in rather large quantities, partly uncombined, in palm oil. Sper-
maceti is the cetyl ester of the acid, whilst the myricyl ester is the chief
constituent of beeswax. The acid is most advantageously obtained
from olive oil, which consists almost exclusively of the glycerides of
palmitic and oleic acids ; also, from Japan wax, a glyceride of
palmitic acid (B. 21, 2265). The acid is artificially made by heating
cetyl alcohol with soda lime to 270° ; also by fusing together oleic acid
and potassium hydroxide.
Margarie Acid, n-Heptadecylic Acid, CH3(CH2)15CO2H, does not apparently
exist naturally in the fats (B. 38, 1247). It is made in the laboratory by
boiling cetyl cyanide with potassium hydroxide.
Stearic Acid, n-Octodecylic Acid, CH3(CH2)16CO2H, is associated
with palmitic and oleic acids as a mixed glyceride in solid animal fats
— the tallows. Its name is derived from orea/> =tallow.
Arachidic Acid, CH8(CH2)18CO2H, occurs in earth-nut oil (from Arachis
hyppgtsa). It has been obtained synthetically from acetoacetic ester and octodecyl
iodide (from stearyl aldehyde) (B. 17, R. 570). For products derived from
arachidic acid, see B. 29, R. 852. Theobromic Acid, m.p. 72°, derived from
cacao butter, appears to be identical with arachidic acid.
Behenic Acid, C22H44O2, is found in the oil obtained from Moringa ole'ifera,
and has been prepared by the reduction of iodobehenic acid from erucic acid
(B. 27, R. 577 ; C. 1807, II. noi).
Cerotic Acid, C26H62O2 or C2?H64O2 (B. 30, 1418), occurs together with
melissic acid, in a free condition in beeswax, and may be extracted from this
by means of boiling alcohol. As its ceryl ester, it is the chief constituent of Chinese
wax (B. 30, 1415). Its name is derived from cera=wax.
Melissic Acid, C30H60O2. m.p. 88°, is formed from myricyl alcohol (p. 121)
when the latter is heated with soda-lime. It is a waxy substance, and appears
to be a mixture of two acids.
The acids mentioned in the table, but not described here, have been prepared
by the usual synthetic methods. Some of them will be encountered later in
the form of oxidation or reduction products of complicated, complex aliphatic
derivatives.
SYNTHESIS AND DECOMPOSITION OF THE FATTY ACIDS
The synthetic methods for the production of the fatty acids are not all equally
well adapted for this purpose. Thus, methods 5, 6, and 7 (p. 252) are restricted to
the synthesis of the simplest members of the series. Reactions more satisfactory
SYNTHESIS AND DECOMPOSITION OF FATTY ACIDS 263
than these, and especially fitted for the synthesis of the higher mono- and dialkyl
acetic acids, are based on the behaviour of acetoacetic ester and malonic ester
(methods n and 13). However, trialkylacetic acids cannot be synthesized in
this way. It is only the fourth method of formation — the synthesis of an acid
cyanide from the iodide of an alcohol containing an atom less of carbon than
the cyanide and the acid derived from it — that will lead to the synthesis of not
only mono- and di-, but also of trialkyl acetic acids. The nitriles of the latter—
e.g. of trimethyl acetic acid, dimethyl ethyl acetic acid, and diethyl methyl acetic
acid — have been obtained from the iodides of the corresponding tertiary alcohols.
The nitrile synthesis renders the formation of acids from alcohols possible, and
inasmuch as acids can be reduced to aldehydes and alcohols by the fourth trans-
position method (p. 255), the synthesis of these two classes of bodies is made
possible. Lieben, Rossi, and Janecek (A. 187, 126), beginning with methyl
alcohol, systematically prepared the normal acids and corresponding alcohols
up to cenanthic acid, according to the following scheme :
CH3OH > CH8I > CH3CN -
Methyl Alcohol. Methyl Iodide. Methyl Cyanide.
CH3CO2H
Acetic Acid.
CH3CHO
Acetaldehyde.
CH2OH
CH3 CH3
Ethyl Alcohol. Ethyl Iodide.
CH,CN
CH3
Ethyl Cyanide.
CH2COaH
CH3
Propionic Acid.
CH2.CHO
| etc.
CH3
Propionic Aldehyde.
The following reactions come into consideration in the breaking-down or
decomposition of the normal fatty acids :
(1) The method of formation 9 (p. 253) of carboxylic acids: oxidation of
mixed methyl n-alkyl ketones, in which the CO-group remains in combination
with the methyl group.
(2) The reaction 10 (p. 255) of acid amides with bromine and potassium
hydroxide.
(3) The action of iodine on the silver salts.
(4) The oxidation of the olefine carboxylic acids, produced by bromination
and subsequent abstraction of HBr.
(5) The heating of a-hydroxy-fatty acids, obtained from a-bromo- fatty acids,
whereby the next lower aldehyde is obtained (comp. pp. 192, 193).
i. The first of these reactions was employed systematically by F. Krafft
for the breaking-down of stearic acid into normal fatty acids of known con-
stitution, from which it was concluded that stearic acid and the lower homologues
derived from it possessed normal constitution. Upon distilling barium stearate,
(C17H35CO2)2Ba, and barium acetate, (CH3CO2)2Ba, heptadecyl methyl ketone,
C17H35COCH3, results. When this is oxidized it breaks down into margaric
acid, C18H33CO2H, and acetic acid. Barium margarate and barium acetate
yield hexadecyl methyl ketone, C16H38.CO.CH3> and this, by oxidation, passes into
palmitic acid, C16H31CO2H, and acetic acid, etc. :
C17H36COO>B
C17H35COO>Ba
Barium Stearate.
(CH,C02)kBa
CrO,
C17H,6COCH,
Ct,H83C02H
Margaric Acid.
C16H81CO,,H
Barium Margarate. Palmitic Acid.
2. A. W. Hofmann (B. 19, 1433) discovered the second method, which will be
treated more fully in connection with the acid amides and nitriles (pp. 158, 274) ;
here only the diagrammatic representation of the course of reaction need be
given. When the acid amides are treated with bromine and sodium hydroxide they
lose the CO-group in the form of CO2 and pass into the next lower primary amines,
which, by further treatment with the same reagents, become converted into the
nitrile of a carboxylic acid containing an atom less of carbon, and its amide is
still capable of a like transformation. By this method the higher, more easily
obtained, normal fatty acids can be changed into lower acids :
C13H27CONH,
Myristamide.
Tridecylaminc.
•C12H26CN —
Tridecyl Nitrile.
CltH2BCONH
Tridecylamide.
264 ORGANIC CHEMISTRY
* Action of iodine on silver salts : silver acetate yields, in addition to
CO2,' the acetic methyl ester ; silver capronate yields CO2 and caproic amyl
ester (B. 25, R. 581 ; 26, R. 237) :
2CH3C02Ag+I2=CH3C02CH3-fC02+2AgI.
4 Bromo-valeric acid, obtained from the fatty acid, gives up HBr to diethyl
aniline or quinoline, becoming changed to ethyl acrylic acid. This olefinc mono-
carboxylic acid yields, on oxidation, propionic acid (C. 1899, I. 778) :
CH3CH2.CH2CH2.COOH > CH8CH2.CH=CHCOOH > CH3.CH2.COOH.
Valeric Acid. Ethyl Acrylic Acid. Propionic Acid.
5. a-Bromopclargonic acid, from the simple acid, when boiled with aqueous
potassium hydroxide, yields a-hydroxypelargonic acid, which gives octyl
aldehyde on being heated to 260° :
CHi[CHJTCH,COOH > CH3[CH2]7CHBrCOOH >
CH3[CH2]7CH(OH)COOH > CH3[CH2]7CHO.
TECHNICAL APPLICATION OF THE FATS AND OILS
Animal fats, especially mutton and beef-tallow, the nature of which
was made clear by the classic researches of Chevreul in the beginning of
last century, consist mainly of a mixture of glycerol esters of palmitic,
stearic, and oleic acids, which are commonly called palmitin, stearin,
and olein. They have been used in the preparation of artificial butter
(margarine), in the manufacture of stearin candles, soaps, and plasters
from the acid esters contained in them, and for the isolation of glycerol,
which is used in part as such and in part in the form of nitroglycerine.
Palm oil, coconut oil, and olive oil are also used as raw material.
The so-called stearin of candles consists of a mixture of stearic and
palmitic acids. For its preparation, beef-tallow and suet, both solid
fats, are saponified with calcium hydroxide or sulphuric acid, with
superheated steam, or by the action of ferments present in some seeds,
such as castor-oil beans (B. 37, 1436). The acids which separate are
distilled with superheated steam. The yellow, semi-solid distillate,
a mixture of stearic, palmitic, and oleic acids, is freed from the liquid
oleic acid by pressing it between warm plates. The residual, solid
mass is then melted together with some wax or paraffin, to prevent
crystallization occurring when the mass is cold, and moulded into
candles.
When the fats are saponified by potassium or sodium hydroxide,
salts of the fatty acids — soaps — are produced, e.g. sodium palmitate,
according to the equation :
CH2O.CO(CH2)14.CH3 CH2.OH
CHO.CO(CH2)14.CH3+3NaOH = CH.OH+3CH3(CH2)14CO2Na.
CH2O.CO(CH2)M.CH, CH2.OH
Palmitin. Glycerol + Sodium Palmitate.
The sodium salts are solids and hard, whilst those of potassium are
soft. Sodium chloride will convert potassium soaps into sodium soaps.
In small quantities of water these salts of the alkalis dissolve com-
pletely, but with an excess of water they suffer decomposition, some
DERIVATIVES OF THE ACIDS 265
alkali and fatty acid being liberated. This is the cause of the emulsifying
action of soap, whereby it is enabled to take up fatty materials, and so
exercise its detergent action (B. 29, 1328). The other metallic salts
of the fatty acids are sparingly soluble or insoluble in water, but gene-
rally dissolve in alcohol. The lead salts, formed directly by boiling
fats with litharge and water, constitute the so-called lead plaster.
The natural fats almost invariably contain several fatty acids. To separate
them, the acids are set free from their alkali salts by means of hydrochloric
acid and then fractionally crystallized from alcohol. The higher, less soluble
acids separate out first. The separation is more complete if the acids be
fractionally precipitated. The free acids are dissolved in alcohol, saturated
with ammonium hydroxide, and an alcoholic solution of magnesium acetate
added. The magnesium salt of the higher acid will separate out first ; this is
then filtered off and the solution again precipitated with magnesium acetate.
The acids obtained from the several fractions are subjected anew to the same
treatment, until, by further fractionation, the melting point of the acid
remains constant — an indication of purity. The melting point of a mixture
of two fatty acids is usually lower than the melting points of both acids (the
same is the case with alloys of the metals).
Lanoline, or wool fat, is used in medicine.
DERIVATIVES OF THE FATTY ACIDS
I. ESTERS OF THE FATTY ACIDS
The esters of organic acids resemble those of the mineral acids in
all respects (p. 130), and are prepared by analogous methods.
Methods of Formation. — (i) By direct action of acids and alcohols,
whereby water is formed at the same time :
C2H5.OH+C,H3O.OH=C2H5.O.C2H30+H20.
This reaction, as already stated, only takes place slowly (p. 131) ; heat hastens
it, but it is never complete. A detailed investigation into the formation of
esters, which is of importance to the study of chemical dynamics, was carried
out by Berthelot.
If equivalent quantities of alcohol and acid be mixed, after a certain time
a state of equilibrium will prevail between alcohol, acid, ester, and water ; if
any further quantity of ester were formed it would be hydrolyzed back to alcohol
and acid by the water. In the case of acetic acid and ethyl alcohol, for example,
this point is reached when about two-thirds of the acid has been esterified. If,
however, an excess of alcohol is added to the mixture, the point of equilibrium
is shifted in the direction of increased ester formation, so that a mixture of one
equivalent of acetic acid and eight equivalents of alcohol is only in equilibrium
when 0-945 equivalent of ester have been formed. The course of such a reaction
is directed by the Law of Mass Action, developed by Guldberg and Waage (1867),
and by van 't Hoff, which enunciates that the reaction between two bodies
is dependent, not only on their affinity constant, but also on their relative con-
centrations, so that reactions between substances of slight affinity but in high
concentration may balance those of high affinity and little concentration. Equili-
brium is defined by the equation :
cr-.c?..,=c<r-.c<?.v or
where «j and «2 represent the two molecules resulting from the reacting molecules
ml and w2, Clt C2, C\, C'? their relative concentrations, K the affinity constant
for % and nt in the direction of reaction towards m^ and mt, and K' the affinity
266 ORGANIC CHEMISTRY
constant of mx and m2 towards wx and nz. K is the constant for the mixture of
all four compounds — alcohol, acetic acid, ester, and water. A collection of the
various calculations applicable to such reactions is found in B. 17, 2177 ; 19,
1700. Menschutkin has investigated the ester formation of various homologous
series of acids and alcohols (A. 195, 334 ; 197, 193 ; B. 15, 1445, 1572 ; 21,
R. 41). It was found that the normal primary alcohols possessed the same
velocity of reaction except methyl alcohol, which showed an increased value.
The secondary alcohols entered more slowly into combination, and the tertiary
slowest of all. Among the acids, formic acid exceeded that of acetic acid, and
this in turn the homologues, in the initial velocity of esterification ; apart from
this they showed a diminishing velocity with increasing molecular complexity.
Acids in which a primary alkyl group was contiguous to a carboxylic group, had
a greater velocity than when a secondary alkyl group occupied that position,
which in turn was greater than when a tertiary group was substituted.
It can be seen that the process of esterification is favoured, i.e. the position
of equilibrium can be displaced in the direction of complete reaction, by the
withdrawal of the ester as soon as it is formed, such as can occur if it is sufficiently
volatile to be distilled off. Further, the velocity of reaction, i.e. the time taken
to reach equilibrium, can be greatly accelerated by the addition of mineral acids,
such as hydrochloric, sulphuric, or other strong acids, which act as catalyzers,
as they do, for instance, in the inversion of sucrose, etc. (B. 39, 711, etc.).
The above account indicates the working conditions for the preparation of
esters, (a) A mixture of acid or its salt, alcohol and sulphuric acid is distilled.
(b) Or, in the case of esters of slight volatility, the acid or its salt is dissolved in
excess of alcohol, or the alcohol in the acid, and gaseous HC1 is passed into the
mixture ; or else sulphuric acid is added, and the ester is thrown out by the addition
of water. With many acids a very suitable esterif ying agent is a dilute solution of
hydrochloric or sulphuric acid in alcohol (B. 28, 3201, 3215, 3252). In many
cases it is advantageous to act on the carboxylic acid with an equivalent quantity
of alcohol and an excess of sulphuric acid (C. 1905, I. 365). (See also Vol. II. :
Esters of aromatic carboxylic acids.)
The following are noteworthy methods of formation :
(2) Double decomposition of the alkyl esters of mineral acids with
salts of the organic acids :
(a) By the action of the alkylogens on salts of the acids, e.g.
iodoalkyls and silver salts :
C2H6I+CH3COOAg=CH3COOC2H5+AgI.
(b) By the dry distillation of a mixture of the alkali salts of the
fatty acids and salts of alkyl sulphates :
(c) The methyl ester can be prepared from the sodium or potassium
salt of the acid and dimethyl sulphate (B. 37, 4144 ; A. 340, 244) :
(30) By the action of acid chlorides (p. 269) or acid anhydrides
(p. 271) on the alcohols or alcoholates ; and by the action of anhydrides
or acid chlorides on alcohols in the presence of tertiary bases such as
pyridine (C. 1901, II. 1223) :
C8H5OH+CH3COC1=CH3COOC2HB+HC1.
C2H6OH + (CH8CO)20=CH3COOC2H5+CH3COOH.
In these reactions, it is sometimes more convenient to employ instead of the
simple alcoholates, the halogen magnesium alcoholates ROMgX (prepared from
?TTy«Lmagn5smm halides an<i alcohols), on account of their solubility in ether
(IS. o9, 1736).
DERIVATIVES OF THE ACIDS 267
(36) By the action of acid chlorides on alkyl ethers in the presence
of zinc chloride, e.g. ethyl ether and acetyl chloride yield chloromethane
and ethyl acetate (C. 1907, I. 1265).
(4) Acid nitriles are converted directly into esters when they are
dissolved in alcohol and are subjected to the passage of HC1 gas, or are
heated with a little dilute acid (p. 280).
(5) Electro-syntheses of monocarboxylic esters (p. 253).
Properties. — Usually, the esters of fatty acids are volatile, neutral
liquids, soluble in alcohol and ether, but generally insoluble in water.
Many of them possess an agreeable fruity odour, and are prepared in
large quantities, as they find extended application as artificial fruit
essences. Nearly all fruit-odours may be made by mixing the different
esters. The esters of the higher fatty acids occur in the natural
varieties of wax.
Consult B. 14, 1274 ; A. 218, 337 ; 220, 290, 319 ; 223, 247, upon
the boiling points, the specific gravities and specific volumes of the
fatty acid esters.
Reactions. — (i) When the esters are heated with water they undergo
a partial decomposition into alcohol and acid. This decomposition
(saponification) (p. 251) is more rapid and complete on heating with
alkalis in alcoholic solution :
C2H3O.OC2H6 + KOH=C2H3O.OK+C2H6.OH.
Consult A. 228, 257, and 232, 103 ; B. 20, 1634, upon the velocity of saponifi-
cation by various bases.
(2) Ammonia changes the esters into amides (p. 275) :
C2H3O.OC2H6+NH3=C2H3O.NH,+C2H6.OH.
(3) The halogen acids convert the esters into acids and haloid-esters (A. 211,
178):
CaH3O.O.C2H6+HI =C2H3O.OH -fC2H6I.
(4) By the action of PC15 the substituted hydroxyl oxygen is replaced by
chlorine, and both radicals are converted into halogen derivatives. Compare
oxalic ester for the course of this reaction :
C2H3O.O.C2H5+PC15=C2H3O.C1+C2H6C1+POC13.
(5) The esters, containing alcohol radicals with high molecular weight, break
down, when heated or distilled underpressure, into fatty acids and defines (p. 83).
(6) Esters are reduced by sodium in absolute alcohol solution to the alcohol
corresponding with the acid radical (C. 1905, II. 1700) :
CH3(CH2)4COOC2H8 > CH3[CH2]4CH2OH.
Esters of Acetic Acid. — The Methyl Ester, Methyl Acetate, C,H3O2.CH3, b.p.
57-5°, D0=0'9577, occurs in crude wood-spirit. When chlorine acts on it
the alcohol radical is first substituted : CjjHaOjj.CHsjCl, b.p. 150° ; C2H3O2.CHC12,
b.p. 148°.
The Ethyl Ester, Ethyl Acetate, Acetic Ether, C2H3O2.C2H6, b.p. 77°, m.p.
— 82°, D0 =0-9238, is technically prepared from acetic acid, alcohol, and sulphuric
acid, and constitutes the officinal JEther aceticus. It is the parent substance
for the production of acetoacetic ester, CH3.CO.CH2.CO2.C2H6, a step in the
formation of antipyrine. Chlorine produces substitution compounds of the
alcohol radicals.
n-Propyl Ester, b.p. 101° ; Isopropyl Ester, b.p. 91° ; n-Butyl Ester, b.p. 124° ;
Isobutyl Ester, b.p. 116° ; sec.-Butyl Ester, b.p. in0 ; tert.-Butyl Ester, b.p. 96° ;
n-Amyl Ester, b.p. 148° ; n-Propyl Methyl Carbinol Acetate, (CH3CH2CH2)CH3.*
CHO.COCH,, b.p. 133° ; Isopropyl Methyl Carbinol Acetate, b.p. 125°, is decom-
posed into amylene and acetic acid at 200°.
268 ORGANIC CHEMISTRY
Isobutyl Carbinol Acetate; acetic ester of fermentation amyl alcohol, b.p. 140°,
in dilute alcoholic solution posessses the odour of pears and is employed as
" pear oil." It is used also in the varnish industry.
Acetic n Hexyl Ester, b.p. 169-170°, occurs in the oil of Heracleum giganteum,
and possesses a fruit-like odour. Acetic n-Octyl Ester, b.p. 207°, is also present in
the oil of Heracleum giganteum, and has the odour of oranges.
Allyl Ester, b.p. 98-100°.
For higher acetic esters, see A. 233, 260.
Furthermore, the addition products of the aldehydes and acetic anhydride
are the acetic esters (p. 195) of those glycols not capable of existing in a free
condition. The aldehydes are probably the anhydrides of these bodies.
Later, in the presentation of the polyhydric alcohols their acetic esters will
always be described, for by their saponification a clue can be obtained as to
the number of hydroxyl groups present in the alcohol.
Esters of Propionic Acid. — The Methyl Ester, b.p. 79-5° ; Ethyl Ester, b.p.
98-8° ; n-Propyl Ester, b.p. 122° ; Isobutyl Ester, b.p. 137° ; Isoamyl Ester, b.p.
r6o°, has an odour like that of pine-apples (see A. 233, 253).
Esters of n-Butyric Acid. — Methyl ester, b.p. 102*3°, has an odour like that of
apples ; ethyl ester, b.p. I20'9°, has a pine-apple-like odour, and is employed in the
manufacture of artificial rum. Its alcoholic solution is the artificial pine-apple oil,
n-Propyl ester, b.p. 143°; Isopropyl Ester, b.p. 128°; Isobutyl Ester, b.p. 157°;
Isoamyl Ester, b.p. 178°, possesses an odour resembling that of pears ; n-Hexyl
Ester, b.p. 205 ; and n-Octyl Ester, b.p. 244°, are found in the oil obtained from
various species of Heracleum (see above) ; octyl ester occurs in Pastinaca saliva
(A. 163, 193 ; 166, 80 ; 233, 272).
Esters of Isobutyric Acid.— Methyl I sobutyric Ester, b.p. 92-3°; Ethyllsobutyric
Ester, b.p. no*; n-propyl ester, b.p. 135° (A. 218, 334).
Esters of the Valeric Acids. — n-Valeric Ethyl Ester, b.p. 144° (A. 233, 274);
iso-Valeric Ethyl Ester, b.p. 135° ; iso-Valeric Isoamvl Ester, b.p. 194°.
Methyl Ethyl Acetic Ethyl Ester, b.p. 133-5° (A. 195,' 120) ; Trimethyl Acetic Ethyl
Ester, b.p. 118° (A. 173, 372).
Esters of the Hexoie Acids. — n-Ethyl Ester, b.p. 167° ; Isobutyl Acetic Ethyl
Ester, b.p. 161°.
n-Heptoic Ethyl Ester, b.p. 187-188°; n-Octoic Ethyl Ester, b.p. 207-208°
(A. 233, 282) ; TL-Nonoic Ethyl Ester, b.p. 227-228° ; n-Capric Ethyl Ester, b.p.
243-245°; n-Capric Isoamyl Ester, b.p. 275-290° with decomposition, is the prin-
cipal constituent of the fusel oil of wine.
Laurie Ethyl Ester, b.p. 269° ; Myristic Ethyl Ester, m.p. io-n°, b.p. 295°.
Spermaceti and the Waxes.
Some of the esters with high molecular weights occur already
formed in spermaceti and the waxes. This fact has been noted in
connection with the corresponding alcohols and acids. The waxes
are distinguished from the fats in that they consist of esters of mono-
hydric alcohols with high molecular weight, whereas the fats are the
esters of the irihydric alcohol, glycerol. Spermaceti belongs to the
wax variety.
Spermaceti, Cetaceum, occurs in the oil from peculiar cavities
in the heads of whales (particularly Physeter macrocephalus) , and
upon standing and cooling it separates as a white crystalline
mass, which can be purified by pressing and recrystallization from
alcohol. ^ It consists of Palmitic Cetyl Ester, C16H31O2.C16H33, m.p.
40°, which crystallizes from hot alcohol in waxy, shining needles
or leaflets. It volatilizes undecomposed in a vacuum. Distilled
under pressure, it yields hexadecylene and palmitic acid. When boiled
with alcoholic potassium hydroxide it gives palmitic acid and cetyl
alcohol (p. 122).
ACID HALIDES 269
Waxes. — Ordinary beeswax, m.p. 61-64°, is a mixture of cerotic acid, C26H62Oa
or C27H6<O2, with Myricyl Palmitate, C16H81O2.C30H61. Boiling alcohol extracts
the cerotic acid and the ester, myricin, remains (A. 224, 225).
Consult A. 235, 106, for other constituents of beeswax.
Carnauba wax, m.p. 83°, occurs in the leaves of the carnuba tree, and contains
free ceryl alcohol and various acid esters (A. 223, 283).
Chinese Wax or Insect Wax is obtained by the Coccus ceriferus, Fabr., from
the Chinese ash, Fraxinus chinensis. It consists mainly of Ceryl Cerotate,
Ca,HllOj.C2,HB3, m.p. 81°. It is decomposed into cerotic acid and ceryl alcohol
by alcoholic potassium hydroxide.
2. ACID HALIDES, OR HALOID ANHYDRIDES OF THE FATTY ACIDS
The haloid anhydrides of the acids (or acid halides) are those
derivatives which arise in the replacement of the hydroxyl of acids by
halogens ; they are the halogen compounds of the acid radicals. They
have been termed haloid anhydrides, bcause they can be viewed
as mixed anhydrides (p. 272) of the fatty acids and the halide acids,
corresponding with the method of formation (i) of the acid chlorides.
Acid Chlorides. — (i) From fatty acids and hydrochloric acid, by
means of P2O5 :
pao§
CH3.COOH+HC1 -- > CH3.COCl-f H2O.
(2) By the action of hydrochloric acid gas on a mixture of an
acid nitrile and a carboxylic acid or an anhydride at o°. The hydro-
chloride of the acid amide is produced at the same time (B. 29, R. 87) :
CH3CN+CH,COOH+2HC1=CH,CONH2.HC1+CH8COC1.
(3) By the action of chlorine on aldehydes :
CHjCOH -f-Cl2=CH8COCl+HCl.
(4) A far more important method of formation consists in acting
with phosphorus halides on the acids or their salts — just as the
alkylogens are produced from the alcohols (p. 132) :
(a) C
(6) 3CH8COOH+PC18=3CH8COC1+H3P08
(c) 2CH8COONa+POCl8=2CH8COCl-fNaP08+NaCl.
Should there be an excess of the salt in the latter case, the acid will also act
on it, producing acid anhydrides (p. 271). The action, particularly upon the
salts, is very violent.
(5) Carbon oxychloride (B. 17, 1285 ; 21, 1267) and thionyl chloride (C.
1901, II. 527) react similarly to the phosphorus chlorides on free acids and their
salts ; as well as ^-toluene sulphochloride or sodium chlorosulphonate, NaOSO2Cl,
on the salts (C. 1901, II. 518 ; 1904, I. 65) when acid chlorides and anhydrides
are formed :
C2H8O.OH+COC18=C2H8OC1+C02+HC1
CH3COONa+NaOS02Cl=CH3COCl + (NaO)2S02.
(6) Acid chlorides are also produced by the interaction of phosgene and zinc
alkyls (p. 252).
Historical. — Liebig and Wohler obtained the first acid chloride in 1832, when
they treated benzaldehyde, C,H6COH, with chlorine. It. was benzoyl chloride,
CgHjCOCl, the chloride of the simplest aromatic acid — benzoic acid. In 1846,
Cahours discovered the method of producing aromatic acid chlorides by the
270 ORGANIC CHEMISTRY
action of phosphorus pentachloride on monocarboxylic acids. Acetyl chloride
was first prepared in 1851 by Gerhardt (A. 87, 63) by treating sodium acetate
with phosphorus oxychloride.
Acid Bromides.— (i ) The phosphorus bromides act like the corresponding
chlorides on the fatty acids or their salts. A mixture of amorphous phosphorus
and bromine may be employed as a substitute for the bromide itself.
(2) An interesting method for preparing the bromides of brominated acetic
acid consists in acting with air on certain bromide derivatives of ethylene,
whereby oxygen is absorbed, and an intramolecular atomic rearrangement
(p. 36) takes place (B. 13, 1980 ; 21, 3356, II. 702) :
O
unsym.-Dibromethylene, CH2=CBra > CH2Br.COBr, Bromacetyl Bromide.
O
Tribromethylene, CHBr =CBr2 > CHBra.COBr, Dibromacctyl Bromide.
Acid Iodides. — Phosphorus iodide does not convert the acids into iodides of
the acid radicals ; this only occurs when the acid anhydrides are employed,
They are also produced by the interaction of acid chlorides and calcium iodide.
Acid Fluorides. — Acetyl Fluoride is a gas with an odour resembling that of
phosgene. It is formed in the action of AgF or AsF3 on acetyl chloride.
A better procedure consists in allowing acid chlorides to act on anhydrous
zinc fluoride.
Propionyl Fluoride, CH3.CHt.COF, b.p. 44° (C. 1897, I. 1090).
Properties and Reactions. — The acid halides are sharp -smelling
liquids, which fume in the air. They are heavier than water, and at
ordinary temperatures (i) decompose, forming carboxylic acids and
halogen acids. The more readily soluble the resulting acid is in
water, the more energetic will the reaction be.
The acid chlorides act similarly on many other bodies. (2) They
yield compound ethers, or esters, with the alcohols or alcoholates
(p. 266). (3) With salts or acids they yield acid anhydrides (p. 271),
and (4) with ammonia, the amides of the acids, etc. (p. 274). (5) Ter-
tiary amines withdraw HC1 from the acid chlorides, possibly with the
intermediate formation of ketones, R2C=CO, which undergo further
change. Acetyl chloride yields dehydracetic acid, C8H8O4 (q.v.) ;
isobutyl chloride gives tetramethyl diketo-cyclo-butene [(CH3)2C.CO]2
(Vol. II.) (B. 39, 1631).
(6). Sodium amalgam, or better, sodium and oxalic acid (B. 2, 98),
will convert the acid chlorides into aldehydes and alcohols (p.
191), which can be further reduced to primary alcohols (p. 104).
(7) They yield ketones and tertiary alcohols when treated with the
zinc alkyls (pp. 217 and 105). (8) By the action of silver cyanide
they pass into the acid cyanides, which are described as the nitriles
of the a-ketone carboxylic acids. (9) Di- and poly-carboxylic acids,
having the power of forming anhydrides, are converted into their anhy-
drides when treated with acid chlorides (especially acetyl chloride).
Acetyl Chloride, Ethanoyl Chloride, CH3.CO.C1, b.p. 55°, D0=ri3O
is formed according to the general methods applied in the production
of acid chlorides, and by carefully distilling a mixture of acetic acid
(3 parts) and PC13 (2 parts). Or, by heating POC13 (2 molecules)
with acetic acid (3 molecules), as long as HC1 escapes, and then
distilling (A. 175, 378). The acetyl chloride is purified by a second
distillation, this time over a little dry sodium acetate. It is a
CARBOXYLIC ACID ANHYDRIDES, ACYL OXIDES 271
colourless, pungent-smelling liquid. Water decomposes it very
energetically. For its reactions, consult the preceding paragraphs.
Acetyl chloride forms chlorinated acetic acids (p. 287) with chlorine.
Compare acetyl acetone.
Acetyl Bromide, b.p. 81°. Acetyl Iodide, b.p. 108°. Propionyl Chloride,
CH3.CH2COC1, b.p. 80° ; bromide, b.p. 104° ; iodide, b.p. 127°.
Butyryl Chloride, C4H7OC1, b.p. 101° (B. 34, 4051). Aluminium chloride
changes it to triethyl phloroglucinol (B. 27, R. 507 ; n-bromide, b.p. 128° ; n-
iodide, b.p. 146° ; Isobutyryl Chloride, (CH3)aCH.COCl, b.p. 92°, for reactions
with tertiary amino bases, see p. 270 ; bromide, b.p. 116°.
Valeryl Chloride, b.p. 107° ; Isovaleryl Chloride, C6H,OC1, b.p. H4'5° ; bro-
mide, b.p. 143° ; iodide, b.p. 168°.
Trimethyl Acetic Chloride, (CH8)3CCOC1, b.p. 105-106°; n-Caproyl Chloride,
CH3(CH2)4COC1, b.p. 146° ; Diethyl Acetyl Chloride, (C2H5)2CHCOC1, b.p. 135° ;
Dimethyl Ethyl Acetic Chloride, (CH3)2(CaH6)C.COCl, b.p. 132°.
Consult B. 17, 1378 ; 19, 2982 ; 23, 2384, for the chlorides of the higher
fatty acids.
The boiling point of the normal acid chlorides shows an increase of 48° between
each member of the series and its next but one higher member. This interval
is made up of 28° between a chloride containing an even number of carbon
atoms and the next higher member, which, of course, contains an odd number,
and 20° between this and the nest higher which possesses an even number of
carbon atoms (C. 1899, I. 968).
With these acid chlorides or haloid anhydrides are connected the mixed
anhydrides of a fatty acid with inorganic acids, such as nitric and nitrous acids,
chromic acid, boric acid, arsenious acid.
Diacetyl Orthonitric Acid, (CH3COO)2N(OH)8, b.p. 128°, D1B=i'i97, results
when fuming nitric acid (D. =1-4) reacts with acetic anhydride, or glacial acetic
acid with nitric acid. It is a colourless liquid, fuming in air, and decomposed
by water into acetic and nitric acids. It possesses an oxidizing and nitrating
action. Excess of acetic anhydride converts it into tetranitromethane, C(NO2)4
(B. 35, 2526 ; 36, 2225).
Acetyl Nitrate, CH3COO.NO2, b.p.77 22°, is prepared from N,O5 and acetic
anhydride. It is a colourless mobile liquid, fuming in air, and explodes
when rapidly heated. At 60° it evolves nitrous fumes and forms tetranitro-
methane. With alcohol it forms a mixture of acetic and nitric esters which acts
as a strong nitrating mixture for benzene derivatives (C. 1907, I. 1025).
Acetyl Nitrite, CH3COO.NO, is obtained from silver acetate and NOC1, and
forms an easily decomposed golden-yellow liquid (C. 1904, II. 511).
Acetyl Chromate, (CH8COO)CrO3H, results from mixing CrO3 and glacial acetic
acid (B. 36, 2215).
Triacetyl Borate, m.p. 121°, is obtained from B2O8 and acetic anhydride.
Alcohols produce from it boric ester, whilst carboxylic acids give rise to other
mixed boric anhydrides, such as Tristearyl Borate, (ClgH85O2)B, m.p. 71° (B. 36,
2219).
Acetyl Arsenite, m.p. 82°, b.p.lx 165-170°, is formed from As8O, and acetic
anhydride (C. 1906, I. 21).
3. CARBOXYLIC ACID ANHYDRIDES, ACYL OXIDES
The acid anhydrides are the oxides of the acid radicals. In those
of the monobasic acids two acid radicals are united by an oxygen
atom ; they are analogous to the oxides of the univalent alcohol
radicals — the ethers.
The simple anhydrides, those containing two similar radicals, can usually
272 ORGANIC CHEMISTRY
be distilled, whilst the mixed anhydrides, with two dissimilar radicals, decompose
when heated, into two simple anhydrides :
C2H30>0 _ C2H30>0 , C5H9(X Q
2C6H,CT U •' C2H3CKL h C6H90^
Hence they cannot be separated from the product of the reaction by distillation,
but have to be dissolved out with ether.
Formyl acetyl oxide, HCO.O.COCH3, however, can be volatilized unchanged
under reduced pressure.
Methods of Formation, — (la) The chlorides of the acid radical
are allowed to act on anhydrous salts, such as the alkali salts of the
acids :
CjH.OOK-f C2H3OC1 = £2^3Q>0 + KC1.
(16) The anhydrides of the higher fatty acids can also be produced by the
action of acetyl chloride (B. 10, 1881) (A. 226, 12 ; C. 1899, I. 1070) on the
free acids ; in the latter case mixed anhydrides are also obtained. The action
of the chloride on the free carboxylic acids is assisted by the presence of a tertiary
base, such as pyridine, quinoline, or triethylamine, which takes up the hydro-
chloric acid set free during reaction (B. 34, 2070 ; C. 1901, II. 543).
(2) • Phosphorus oxychloride (i molecule) acts on the dry alkali
salts of the acids (4 molecules). The acid chloride, which is also
produced, reacts immediately on its formation with the excess of
salt:
I Phase : 2C2H8O.OK+POCl3=2C2H3O.Cl-f-KPO3-fKCl
II Phase: C2H3O.OK+C2H3O.C1 = (C2H3O)2
(3) Phosgene, COC12, acts like POC18. In this reaction acid chlorides are also
produced (p. 269).
(4) A direct conversion of the acid chlorides into the corresponding anhydrides
may be effected by reacting with the former on anyhdrous oxalic acid (A.
226, 14) :
2C2H3OC1+C204H2 = (C2H30)2O+2HC1+C02+CO.
Historical.— Charles Gerhardt (1851) discovered the acid anhydrides. The
important bearing of this discovery upon the type theory has already been alluded
to in the Introduction.
Properties and Reactions. — The acid anhydrides are liquids or
solids of neutral reaction, and are soluble in ether. Their boiling
points are higher than those of the corresponding acids, (i) Water
decomposes them into their constituent acids :
(CH3CO)20+H20=2CH,COOH.
(2) With alcohols they yield the esters (C. 1906, II. 1043) :
(CH8CO)20+C2H6OH=CH,COOC2H5+CH8COOH.
(3) Ammonia and primary and secondary amines convert them
into amides and ammonium salts :
(CH8CO)20+2NH,=CH8CONH2-f-CH3COONH4.
with hydrochloric acid, hydro bromic
mpose into an acid halide and free ac
(CH8CO)20+HC1=CH,COC1+CH,COOH.
(4) Heated with hydrochloric acid, hydro bromic and hydriodic
acids, they decompose into an acid halide and free acid :
THIO-ACIDS 273
(5) Chlorine splits them up into acid chlorides and chlorinated acids :
(CHjCO)tO-Kla=CH,COCl+ClCHaCOOH.
(6) Sodium amalgam changes the anhydrides to aldehydes and
primary alcohols.
(7) Aldehydes and acid anhydrides combine to form esters.
Simple Anhydrides. — Acetic Anhydride [Ethane Acid Anhydride],
(C2H3O)2O> b.p. 137°, D0=ro73, is a mobile, pungent-smelling liquid.
It is prepared by distillation of a mixture of anhydrous sodium acetate (three
parts) and POC13 (one part) ; or of the product of reaction of equal parts of
acetyl chloride and sodium acetate. The anhydride can then be dissolved unde-
composed in about ten parts of cold water, and in this form may be used for
acetylating amino-bases in aqueous solution (C. 1905, II. 466 ; 1906, II. 1042).
Propionic Anhydride, (C3H6)aO, b.p. 168°. Butyric Anhydride, b.p. 199°.
Isobutyric Anhydride, b.p. i8i'5°. n-Caproic Anhydride, b.p. 242°, with decom-
position. (Enanthic Anhydride, m.p. 17°, b.p.^ 164°. n-Oetylic Anhydride, m.p.
— i°, b.p.15 186°. Pelargonic Anhydride, m.p. 16°, b.p.16 207°. Palmitic An-
hydride, m.p. 64°. Stearic Anhydride, m.p. 71-77° (C. 1899, 1. 1070 ; B. 33, 3576).
MIXED ANHYDRIDES
Acetyl Formyl Oxide, HCO.O.COCH8, b.p.jg 29°, is prepared by mixing formic
acid and acetic anhydride in the cold, a reaction which can be employed for the
formation of higher homologues. At ordinary pressures it boils with partial
decomposition. Quinoline liberates CO, and alcohols form formyl esters (Bthal,
C. 1900, II. 750). For other mixed anhydrides, see B. 34, 168.
4. ACID PEROXIDES
The peroxides of the acid radicals are prepared by heating the chlorides or
anhydrides in ethereal solution with barium peroxide (Brodie, Pogg. Ann., 121, 382),
or by the action of the ice-cold chloride on sodium peroxide hydrate (B. 33,
1043). Also, by the addition of pure hydrogen peroxide to acetic anhydrides
(A. 298, 288) :
Diacetyl Peroxide, m.p. 30°, b.p.ai 63°, possesses a sharp odour like ozone. It
is insoluble in water, but easily soluble in alcohol and ether. It is very unstable
and acts as a strong oxidizing agent, liberating iodine from a KI solution, and
decolorizing a solution of indigo. Sunlight decomposes it, and it explodes
violently on heating. Water hydrolyzes it into acetic acid and Acetyl Peroxide,
CH jCOOOH, which has not been isolated. Barium hydroxide solution decomposes
it, forming barium acetate and barium peroxide. Propionic Peroxide, (C3H5O)2Oa>
is obtained from propionic anhydride and BaOa : it is a liquid (C. 1903, I. 958).
5. THIO-ACIDS
By the replacement of oxygen in a monocarboxylic acid by sulphur three
results are possible :
1. R/.CO.SH. Thio-acids, Carbothiolic acids.
2. R'.CS.OH Thionic Acids. Carbolthionic acids (comp. Thiamides)
3. R'.CS.SH Dithionic Acids, Carbithionic acids.
a. Thio-acids. — The first thio-acid — thiacetic acid, CH3.COSH, — was obtained
by Kekutt (A. 90, 309) when phosphorus pentasulphide acted on acetic acid.
In its preparation it is advisable to mix the PaS6 with half its weight of coarse
fragments of glass :
5C2H3O.OH+P2S8=5CaH8O.SH+PaOs.
The thio-anhydrides arise in the same manner by the action of phosphorus
sulphide on the acid anhydrides. The thio-acids are produced by the action
VOL. I. T
274 ORGANIC CHEMISTRY
of acid chlorides on potassium hydrogen sulphide, or from phenyl esters and
NaSH in alcoholic solution (C. 1903, I. 816). The disagreeably-smelling thio-acids
correspond with the thio-alcohols or mercaptans (p. 142), their sulphanhydrides
with the acid anhydrides and the simple sulphides, and their disulphides with the
peroxides and alkyl disulphides :
CH3CH2SH CH3COSH CH3COaH
Ethyl Mercaptan. Thiacetic Acid. Acetic Acid.
(CH3CH2)2S (CH3CO)2S (CH3CO)20
Ethyl Sulphide. Thiacetic Anhydride. Acetic Anhydride.
(CH8CH2)2Sa (CH3CO)2Sa (CH3CO)aOa
Ethyl Bisulphide. Acetyl Disulphide. Acetyl Peroxide.
The esters are obtained when the alkylogens react with the salts of the thio-
acids, and the acid chlorides with the mercaptans or mercaptides.
They also appear in the decomposition of alkyl isothioacetanilides with dilute
hydrochloric acid :
Ethyl Isothioacetanilide. Thioacetic Ester. Aniline.
Concentrated potassium hydroxide decomposes the esters into fatty acids and
mercaptans.
Thiacetic Acid, Methyl Carbothiolic Acid, CH8COSH, b.p. 93°, D10=i-o74, is a
colourless liquid. Its odour resembles those of acetic acid and hydrogen sulphide.
It dissolves with difficulty in water, but readily in alcohol and in ether. This acid
has been recommended as a very convenient substitute for hydrogen sulphide
in analytical operations (C. 1901, I. 1148), and is a suitable reagent for acetylat-
ing amines (B. 35, no). The lead salt, (CaH8O.S)aPb, crystallizes in minute
needles, and readily decomposes with the formation of lead sulphide (C. 1897, *•
1090 ; II. 770). Ethyl ester, C2H3O.S.C2H6, b.p. 115°.
When thiacetic acid is heated with zinc chloride, there is formed Tetraethenyl
Hexasulphide, (CH3C)4S,, m.p. 224° (B, 36, 204). ,On the formation of Thio-
propionic Acid, Ethyl Carbothiolic Acid, CaH6COSH, from ethyl magnesium
bromide and carbon oxysulphide, see B. 36, 1009.
Acetyl Sulphide, (C2H3O)2S, b.p. 157°, is a heavy, yellow oil, insoluble in
water. Water gradually decomposes it into acetic and thiacetic acids (B. 24,
3548, 4251).
Acetyl Disulphide, (C2H8O)2Sa, is formed when acetyl chloride acts on
potassium disulphide, or iodine on the salts of the thio-acid.
b. Dithionie Acids. — Just as carboxylic acids result from the treatment of acetyl
magnesium halides with CO2, so the doubly sulphur-substituted carboxylic acids,
dithionic acids, are prepared by the action of CSa on the alkyl magnesium halides :
,C<|H.
They are reddish-yellow oils, of an offensive odour, which can be distilled
without decomposition. They are strong acids, easily oxidized in the air to
solid, stable, yellow disulphides, RCSS.SCSR.
Methyl Dithionic Acid, CH3CS2H, b.p.16 37°, D20= i -24, is prepared from methyl
magnesium iodide and CS2. It is a reddish-yellow oil, of an exceedingly pene-
trating and repulsive odour ; it dissolves with difficulty in water, but easily in
organic solvents. Ethyl Dithionic acid, C2H5CS2H, b.p.17 48°. Propyl Dithionic
acid, b.p.18 59°. Isobutyl Dithionic acid, b.p.88 84°. 1 soamy I Dithionic acid, b.p,10
84 .- (B. 40, 1725.)
6. ACID AMIDES
These correspond with the amines of the alcohol radicals. The
hydrogen of ammonia can be replaced by acid radicals, forming primary,
secondary and tertiary acid amides :
3CONH2 (CH3CO)2NH (CH3CO)8N
(pnmary). Diacetamide (secondary). Triacetamide (tertiary),
ACID AMIDES 275
The primary acid amides have as isomers, the imido-ethers (p. 281) of the
OT-T
formula R'.C<^»rrT. To benzamide (Vol. II.) is ascribed, not only the formula
CaH6C<^NH , but also C6H6C<^NH, since the silver salt and iodoethane give
(~}C* TT
benzimido-ethyl ether, C8H6C<^2 5. The sodium salt is the only one which,
on reacting with iodoethane, gives a benzamide in which the imide group is
ethylated. This is taken as evidence that the metal is most probably united to
the nitrogen atom according to the iso-imido formula. But as little can be
deduced of the constitution of benzamide from a study of its salts as of that of
acetoacetic ester, the nitroparaffins and similar compounds.
The hydrogen of primary and secondary amines, like that of
ammonia, can be replaced by acid residues, giving rise to mixed
amides.
General Methods of Formation. — (i) By the dry distillation of the
ammonium salts of the acids of this series. A more abundant yield
is obtained by merely heating the ammonium salts to about 230°
(B. 15, 979), (Ktindig, 1858). (This method was first applied (1830)
by Dumas to ammonium oxalate with the production of oxamide) :
CH3CO.ONH4=CH3CONHa+H20.
Ammonium Acetate. Acetamide.
A mixture of the sodium salts and ammonium chloride may be substituted for
the ammonium salts. Consult B. 17, 848, upon the velocity and limit of the amide
production.
(2) By the action of ammonia, primary and secondary amines on
the esters whereby Liebig, in 1834, obtained oxamide from oxalic
ester :
CH3CO.O.C2H6-fNH3=CH3CO.NHa-fCaH5.OH
Acetamide.
CH3CO.O.C1H,-fCaH5.NHa=CH3CONHC2H,+C2H5.OH.
Ethyl Acetamide.
This reaction takes place in the cold, particularly in the case of water-soluble
esters; or the ester may be heated with an aqueous or alcoholic solution of
ammonia.
It is one of the so-called reversible reactions, inasmuch as the action of alcohols
on acid amides again produces esters and ammonia (B. 22, 24).
(3) By the action (a) of acid halides, (b) of acid anhydrides on
ammonia, primary and secondary alkylamines. This was the method
which Liebig and Wohler first used in 1832 to prepare benzamide from
benzoyl chloride.
C^a) CH3COC1+2NH3=CH3CONH2+NH4C1
Acetamide.
CH3COC1+2NH2C2H6=CH3CONH.C2H64-N(C2H6)H8C1
Ethyl Acetamide.
CH8COCl+2NH(CaH5)a==CH3CON(C2H5)2+N(CaH6)2H2Cl.
Diethyl Acetamide.
This method is especially well adapted for obtaining the amides of
the higher fatty acids (B. 15, 1728) :
(36) (CH3CO)2O+2NH3=CH3CONH24-CH8.CO2NH4
(CHaCO)2O+2NHaCaHi=CH3CONHC2H6+CH3CO2NH,CtH,.
276 ORGANIC CHEMISTRY
(4) By the addition of one molecule of water to the nitriles of the
acids (p. 278) : (l8o°)=CH3CONHa.
Acetonitrile. Acetamide.
This addition of water frequently occurs in the cold by the action of concen-
trated hydrochloric acid, or by mixing the nitrile with glacial acetic acid and
concentrated sulphuric acid (B. 10, 1061). Hydrogen peroxide in alkaline
solution also converts the nitriles, with liberation of oxygen, into amides (B. 18,
355). For the action of hydrochloric acid on a mixture of nitrile and fatty
acid see (2), formation of acid chlorides.
(5) By the distillation of the fatty acids with potassium thiocyanate :
2C2H30.0H+KSNC=C2H30.NH2+C2H3O.OK+COS.
Simply heating the mixture is more practical (B. 15, 978 ; 16, 2291).
In making acetamide, glacial acetic acid and ammonium thiocyanate are heated
together for several days. By this reaction the aromatic acids yield nitriles.
° (6) By the interaction of fatty acids and carbylamines (p. 247) :
2CH,COOH+C:N.CH,=HCONHCH3 + (CH8CO)aO.
Methyl Formamide.
(7) By the action of the fatty acids on isocyanic acid esters (q.v.) :
CH8COOH+CON.CaH6==CHs.CONHCaH6+COa.
Secondary and tertiary amides are obtained (i) by heating primary acid amides
(B. 23, 2394), alkyl cyanides or nitriles with acids, or acid anhydrides, to 200°.
CHSCONH2 + (CH3CO)20 = (CH3CO)2NH +CH.COOH
CH3CN+CH3COOH = (rH3CO)?NH
Diacetamide.
CKsCN + (CH3CO)aO = (CH3CO)3N.
Triacetamide.
Diacetamide is also prepared by the action of acetyl chloride on acetamide in
solution in benzene (C. 1901, I. 678).
(2) The secondary amides can also be prepared by heating primary amides
with dry hydrogen chloride :
2CaH3ONHa+HCl = (C?H30)2NH+NH4Cl.
Diacetamide.
(3) Mixed amides are further produced by the action of esters of isocyanic
acid on acid anhydrides :
(C2H30)a04-CO:N.C2H6 = (C2H30)2N.C2H6+COa.
Ethyl Diacetamide.
Properties and Reactions. — The amides of the fatty acids are usually
solid, crystalline bodies, soluble in both alcohol and ether. The
lower members are also soluble in water, and can be distilled without
decomposition. As they contain the basic amido-group they are
able to unite directly with acids, forming salt-like derivatives, e.g.
C2H3ONH2.HNO3 and (CH8CONH2)2.HC1, but these are not very
stable, because the basic character of the amido-group has become
greatly weakened by the acid radical. Furthermore, the acid radical
imparts to the NH2-group the power of exchanging a hydrogen atom for
metals, such as mercury or sodium (B. 23, 3037 ; C. 1902, II. 787),
forming metallic derivatives, e.g. (CH3.CO.NH)2.Hg — mercury aceta-
mide, analogous to the isocyanates (from isocyanic acid, HN:CO), and
the salts of the imides of dibasic acids.
The union of the amido-group with the CO-group of the acid radical
is very feeble in comparison with its union with the alkyls in the
amines. The acid amides, therefore, readily absorb water and pass
ACID AMIDES 277
into ammonium salts, or acids and ammonia, (i) Heating with water
effects this, although it is more easily accomplished by boiling with
alkalis or acids. This is a reaction which is not infrequently termed
saponification (p. 251), though hydrolysis is, perhaps, preferable.
CH3CO.NH2+H2O=CH3CO.OH+NH3.
(2) Nitrous acid decomposes the primary amides similarly to the
primary amines (p. 163) :
C8HsO.NHa+HNOa=CaH3O.OH-fN2+H2O.
Acid amides, which saponify with difficulty, may be dissolved in sulphuric acid,
to which sodium nitrite is added in the cold (B. 28, 2783).
(3) Bromine in alkaline solution changes the primary amides to
bromamides (B. 15, 407 and 752) :
C2H3O.NH2+Br2=C2H3O.NHBr+HBr,
which then form amines (p. 159). (4) On heating with phosphorus
pentoxide or chloride, they part with one molecule of water and become
converted into nitriles (cyanides of the alcohol radicals) :
CHS.CO.NH8=CH3.CN+H20.
In this action a replacement of an oxygen atom by two chlorine atoms takes
place ; the resulting chlorides, like CH3.CC12.NH2, then lose, upon further heating,
two molecules of HC1 with the formation of nitriles.
Formamide, H.CONH2. See p. 238.
Acetamide [Ethanamide], CH3CO.NH2, m.p. 82°, b.p.222°, crystal-
lizes in long needles. It dissolves with ease in water and alcohol. In
explaining the methods of producing the amides, and in illustrating
their behaviour, acetamide was presented as the example. Dumas,
Leblanc, and Malaguti first prepared it in 1847, by allowing ammonia
to act on acetic ester. For the preparation of acetamide from
ammonium acetate, see C. 1906, I. 1089.
Acetomethylamide, CH3.CONHCH3, m.p. 28°, b.p. 206° ; Acetpdimethylamide,
CH3.CO.N(CH3)2, b.p. 165-5° ; Acetethylamide, b.p. 205° ; Acetodiethylamide, b.p.
185-186°. Methylene Diacetamide, CHa(NHCOCH8)2, m.p. 196°, b.p. 288°
(B. 25, 310). Chloralacetamide, CC13CH(OH)NHCOCH8, m.p. 117° (B. 10, 168).
Acetamide and butyl chloral yield two isomeric compounds, m.p. 158° and 170°
respectively (B. 25, 1690).
Diacetamide, (C2H3O)8NH, m.p. 77° ; b.p. 222-5-223-5° is readily soluble in
water. (Preparation, p. 276.)
Methyl Diacetamide, (CH3CO)2N.CH3> b.p. 192°. Ethyl Diacetamide, b.p. 185-
192°.
Triacetamide, (C2H3O)3N, m.p. 78-79°. (Preparation, p. 276.)
Acetochlor amide, CH3CONHC1, m.p. 110°.
Acetobromamide, CH3CONHBr +H2O, forms large plates, and melts in an anhy-
drous condition at 108° (B. 15, 410). The production of acetochloramylamide
CH3CO.NC1C,NU, from hypochlorous acid and aceto-amylamide, and from acetic
anhydride and chloramylamine in glacial acetic acid (B. 34, 1613), is taken as a
demonstration that in such compounds the halogen atom is joined to the nitrogen
atom.
Higher homologous primary Acid Amides :
Propionamide, m.p. 75°, b.p. 210°.
n-Butyramide, m.p. 115°, b.p. 216°. Isobutyramide, m.p. 128°, b.p. 216-220*.
n-Valer amide, m.p. 114—116°.
278 ORGANIC CHEMISTRY
Trimetkyl Acetamide, m.p. 153-154°. b-P- 2I2° > n-Capronamide m.p ioo«,
bD 22 s°' Methyl n-Propylacetamide, m.p. 95°: Methyl I sopropylacetamide,
mo 129* '• JSO&M^/ Acetamide, m.p. 120°; Diethyl Acetamide, m.p. 105°, b.p.
*yOr*3?i<E*ant*amitt6t m.p. 95°, b.p. 250-258°; n-Caprylamine, m.p. 105-106°;
Pelargonamide, m.p. 92-93° ; n-Caprinamide, m.p. 98°.
m.p. 102°, b.p.12.5 199-200°; TndecylaiM m.p. 98-5 ;
««ra»M m.p. , ..12.5 - ..
Myristamide, m.p. 102°, b.p.12 217° ; Palmitamide, m.p. 106°, b.p „ 235-236 ;
Stearamide, m.p. 108-5-109°, b.p.12 250-251° (B. 15, 977- 1729 I 19, M33; 24,
2781 ; 26, 2840).
7, ACID HYDRAZIDES
The mono-acyl hydrazides (C. 1902, 1. 21) are obtained by the interaction of
hydrazine and the acid esters, whilst the sym.-diacyl hydrazides are prepared
from hydrazine and the acid anhydrides (B. 34, 187). The latter-named bodies
can also be obtained by heating monoacyl hydrazines and treating the product
with iodine. Sym.-diacetohydrazide, heated with acetic anhydride, yields tri-
acetohydrazide and tetra-acetohydrazide (B. 32, 796).
The mono-acyl hydrazides condense with aldehydes and ketones with the
production of water. The sym.-diacyl hydrazines react with zinc chloride or
phosphorus pentoxide to form dialkyl pyrrodiazoles ; with alcoholic ammonia,
yielding dialkyl pyrrodiazoles ; and with phosphorus pentoxide, forming dialkyl
thiodiazoles. (B. 32. 797)-
Acetohydrazine, CH3CONH.NHa, m.p. 62°. Acetobenzalhydrazine, CH3CO.-
NH.N:CH.C«H6, m.p. 134°; sym.-Diacetohydrazine, m.p: 138°; b.p.16 209°.
Triacetohydraxine, b.p.ls 181°, Tetra-acetohydrazine, m.p. 85°, b.p.1$ 141°.
8. ACID AZIDES
Although the acid azides show a great chemical similarity to the acid halides
(p. 269), they are best examined together with the acid hydrazides, on account
of their generic connections. They are formed by the action of monoacyl hydra-
zine hydrochlorides on alkali nitrites.
Propionyl Azide, CH3.CH2.CONS, is a volatile colourless liquid, of pungent
odour ; with alcohol it forms ethyl urethane (C. 1902, 1. 22).
9. THE FATTY ACID NITRILES OR ALKYL CYANIDES
These are compounds in which one carbon atom, combined with an
alkyl group R'.C= — a residue present in every fatty acid — replaces the
three hydrogen atoms of ammonia, e.g. CH3C=N, acetonitrile. It is
true that in the nitrile bases (tertiary amines and amides) the nitrogen
atom is also joined with three valences to carbon, but three alkyl
residues are in union with three different carbon atoms.
The acid nitriles are also called alkyl cyanides, because they may be
considered as being alkyl ethers of hydrogen cyanide, H.C=N.
Being intermediate step in the synthesis of the fatty acids from the
alcohols, these nitriles merit especial consideration.
The following general methods are employed for their preparation :
(i) Nucleus-synthesis from the alcohols : (a) by heating the alkyl-
ogens with potassium cyanide in alcoholic solution to 100° ; (b) by
the distillation of potassium alkyl sulphates with potassium cyanide
(hence the name alkyl cyanides) :
(ia) C2H6I+KNC=C±H6CN+KI
(16) S04<K2H8 +KNC-C1H4CN-f K.SOf
THE FATTY ACID NITRILES OR ALKYL CYANIDES 279
Isocyanides (p. 247) form to a slight extent in the first reaction. They can be
removed by shaking the distillate with aqueous hydrochloric acid (whereby the
isonitrile is converted into formic acid and a primary amine), until the unpleasant
odour of the isocyanides has disappeared, then neutralizing with soda and drying
the nitriles with calcium chloride.
(2) By heating alkyl isocyanides or alkyl carbylamines (p. 247) :
250°
CH3CH2NC > CH3CH2CN.
(3) By the dry distillation of ammonium salts of the acids with
P205, or some other dehydrating agent (hence the term acid nitrite).
CH3.CO.O.NH4-2H2O=CH3.CN.
Ammonium Acetate. Acetonitrile.
The corresponding acid amide is an intermediate product.
(4) By the removal of water from the amides of the acids when
these are heated with P2O5, P2$5, or phosphorous pentachloride (see
amide chlorides, p. 277) :
CH3.CO.NH2+PC1S=CH3.CN+POC13+2HC1
5CH8.CO.NH2+P2S6=5CH5.CN+P206+5H2S.
(5) By the distillation of fatty acids with potassium thiocyanate
(B. 5, 669), or lead thiocyanate (B. 25, 419), during which a compli-
cated reaction occurs. It is assumed that a thioamide is first formed
which loses H2S, changing into the nitrile, or that a carboxyl is
exchanged for a CN-group.
(6) Primary amines, containing more than five carbon atoms,
are converted, by potassium hydroxide and bromine, into nitriles :
CfH16CH2NH24-2Br2+2KOH=C7H16CH2NBr2+2KBr4-2H20
C7H15CH2NBr2+2KOH=C7H16CN+2KBr+2H2O.
As the primary amines can be obtained from acid amides containing
a carbon atom more, these reactions will serve for the breaking-down
of the fatty acids (p. 263).
(7) Nitriles result when aldoximes arc heated with acetic anhydride or with
thionyl chloride (B. 28, R. 227) :
CH3CH=N.OH + (CH8CO)2O = CH3C=N+2CH,.COOH.
(8) On the application of heat to cyanacetic acid and alkylized cyanacetic acid,
nitriles result :
CNCH,.CO2H=CNCH8+CO2.
The nitriles occur already formed in bone-oils and in gas tar.
Historical. — Pclouze (1834) discovered propionitrile on distilling barium ethyl
sulphate with potassium cyanide (A. 10, 249). Dumas (i 847) obtained acetonitrile
by distilling ammonium acetate alone, or with P2O6 ; the same occurred with the
latter reagent and acetamide (p. 277). Dumas, Malaguti and Leblanc (A. 64, 334)
on the one hand, and Frankland and Kolbe (A. 65, 269, 288, 299) on the other,
demonstrated (1847) the conversion of the nitriles into their corresponding acids
by means of potassium hydroxide or dilute acids, and thus showed what import-
ance the acid nitriles possessed for synthetic organic chemistry.
Properties and Reactions. — The nitriles are liquids, usually insoluble
in water, possessing an ethereal odour, and distilling without decom-
position.
Their reactions are based upon the easy disturbance of the triple
28o ORGANIC CHEMISTRY
union between nitrogen and carbon, and are mostly additive reactions.
Acid nitriles may be considered to be unsaturated compounds, in the
same sense as are the aldehydes and ketones (pp. 23, 190). Their
neutral character distinguishes them from hydrocyanic acid, the
nitrile of formic acid, which they resemble as regards the reactions
of their C=N-group.
(1) Nascent hydrogen converts them into primary amines (p. 158) (Mendius).
This reduction is most easily accomplished by means of metallic sodium and
absolute alcohol (B. 22, 812).
(2) The nitriles unite with the halogen acids, forming amide and imide
halides (p. 281).
(3) Under the influence of concentrated sulphuric acid they take
up water and become converted into acid amides (p. 274). When
heated to 100° with water the acid amides first formed absorb a second
molecule of water and change to the fatty acid and ammonia. The
nitriles are more readily hydrolyzed by heating them with alkalis or
dilute acids (hydrochloric or sulphuric acid). Esters are produced when
the acids, in a solution of absolute alcohol, act on the nitriles.
(4) The nitriles form thiamides with H2S (p. 281).
(5) They combine with alcohols and HC1 to form imido-ethers (p. 281).
(6) With fatty acids and fatty acid anhydrides they yield secondary and
tertiary amides (p. 276).
(7) The nitriles become converted into amidines with ammonia and the
amines (p. 282).
(8) Hydroxylamine unites with them to form amidoximes (p. 283). Metallic
sodium induces in them peculiar polymerizations. In ethereal solution, dimole-
cular nitriles result : imides of fi-ketonic nitriles. All these reactions depend upon
the additive power of the nitriles, the triple carbon-nitrogen union being broken.
If, however, sodium acts on the pure nitriles at a temperature of 150° the
products are trimolecular nitriles, so-called cyanethines (q.v.), pyrimidine deriva-
tives :
2CH8CN — > CH3.C(NH).CH2.CN
Imido-acetic Nitrile.
N— C(CH3)=N
3CH,CN ^CH..t_cH=c.NHr
Cyaue thine (q.v.).
Acetonitrile, Methyl Cyanide [Ethane Nitrile], CH3CN, m.p.
—41° C., b.p. 8r6°, D15 =0*789, is a liquid with an agreeable odour.
It is usually prepared by distilling acetamide with P2O5. Consult
the general description of acid nitriles for its methods of formation,
its history and its reactions. It may, however, be mentioned here that
acetonitrile can be produced from hydrocyanic acid and diazomethane
(B. 28, 857). It combines with Cu2Cl2 to form (CH8CN)2Cu2Cl2
Higher Homologous Nitriles.— Propionitrile, Ethyl Cyanide, [Propane Nitrile],
C2H,.CN, b.p. 98°, D0 0-801.
n-Butyronitrile, b.p. 118-5°, has the odour of bitter-almond oil. Isobutyro-
™t™, b.p. 107°; n-Valeronitrile, b.p. 140-4°; Isopropyl Acetonitrile, b.p. 129°;
Methyl Ethylacetonitrile, b.p. 125°; Trimethyl Acetonitrile, m.p. 15-16°, b.p.
105-106 ; Isobutyl Acetonitrile, b.p. 154°; Dielhyl Acetonitrile, b.p. 144-146°;
Dimethyl Ethyl Acetonitrile, b.p. I28-i3o° ; n-CEnanthyl Nitrile b.p. 175-178°;
THIAMIDES 281
n-Caprilonitrile, b.p. 198-200° ; Pelargonitrile, b.p. 214-216° ; Methyl n-Hexyl-
Acetonitrile, b.p. 206°; Lauronitrile, b.p.100 198°; Tridecylonitrile, b.p. 275°;
Myristonitrile, m.p. 19°, b.p. 226-5°; Palmitonitrile, m.p. 29°, b.p.100 251-5°;
Cetyl Cyanide, m.p. 53° ; Stearonitrile, m.p. 41°, b.p.100 274-5°.
Several classes of compounds bear genetic relations to the acid
amides and nitriles, but these will be considered after the nitriles.
10. AMIDE CHLORIDES AND n. IMIDE CHLORIDES (W attach, A. 184, i)
The amide chlorides are the first unstable products formed during the action of
PCI 5 on acid amides. They lose hydrochloric acid and become converted into
imide chlorides, which by a further separation of hydrochloric acid yield nitriles :
/NHa PC16 /NH2 -HC1 ,*NH -HC1
CH3C/ ^CH3cA:i >CHtcf ^CH3C=EN
^O \C1 XC1
Acetamide. (Acetamide Chloride.) (Acetimide Chloride.)- Acetonltrile.
The addition of HC1 to the nitriles produces the imide chlorides. Hydro-
bromic and hydriodic acids are added more readily than hydrochloric acid to
nitriles (B. 25, 2541):
.NH /NHa /KH2
CH3Cf CH3C^-Br CH3C^-I
\Br \Br M
Acetimide Bromide. Acetamide Bromide. Acetamide Iodide.
If a hydrogen atom of the amide group be replaced by an alcohol radical, the
imide chlorides will be more stable. On being heated, however, they lose hydro-
chloric acid in part and pass into chlorinated bases.
(i) Water changes the imide chlorides back into acid amides. The chlorine
atom of these bodies is as reactive as the chlorine atom of the acid chlorides.
(2) Ammonia and the primary and secondary amines change the imide chlorides
to amidines (p. 282). (3) Hydrogen sulphide converts the imide chlorides into
thiamides.
12. IMIDO-ETHERS* (Pinner, B. 16, 353, 1654; *7> l84» 2O°2)
NH
The imido-ethers may be regarded as the esters of the imido-acids,
a formula which has, in recent times, been proposed for the acid amides (p. 275) ;
(comp. also the Thiamides).
The hydrochlorides of the Imido-ethers are produced by the action of HC1
on an ethereal mixture of a nitrile with an alcohol (in molecular quantities) :
Acetimido-ether.
Formimido-ether (p. 243). Acetimido-Ethyl Ether, b.p. 94°, when liberated
from its HCl-salt by means of NaOH, is a peculiar-smelling liquid. Ammonia
and the amines convert the imido-ethers into amidines. Shaking the imido-ether
hydrochlorides with alcohol produces ortho-esters (p. 284).
13. THIAMIDES
As in the case of the acid amides (p. 274), so here with the thiamides two
formulas are possible :
R'.C<gH« R'.C<^H> and E'.C<gH
• Die Imidoaether und ihre Derivate von A. Pinner, 1892.
282 ORGANIC CHEMISTRY
The thiamides are formed (i) by the action of phosphorus sulphide on the
acid amides ; (2) by the addition of H2S to the nitriles (p. 280) :
CH8.CN+H2S=CH3.CS.NH2.
Acetonitrile. Thiacetamide.
(i ) The thiamides are readily broken up into fatty acids, H2S, NH, and amines.
(2) They yield thiazole derivatives with chloracetic ester, chloracetone, and
similar bodies.
(3) Ammonia converts them into amidines.
(4) The action of hydroxylamine results in the production of oxamidines.
Thiacetamide, m.p. 108° (A. 192, 46; B. 11, 340). Thiopropionamide,
m.p. 42-43° (A. 259, 229).
14. THIO-IMIDO-ETHERS
are derived from the imidothiohydrin form of the thioamides. They are pre-
pared, analogously to the imido-ether's, from the nitriles with mercaptans and
HC1 (B. 38, 3464). Acetimido-Thiophenyl Ether, CH3C<^<?H ,is obtained from
its hydrochloride by the action of sodium hydroxide. It is an unstable yellow
syrup. The hydrochloride, m.p. 120°, with decomposition, is prepared from
acetonitrile, thiophenol (Vol. II.) and HC1.
15. AMIDINES, R-C< (A. *84, 121 ; 192, 46)
The amidines, containing an amide and imide group, whose hydrogen atoms
are replaceable by alkyls, may be considered to be derivatives of the acid amides,
in which the carbonyl oxygen is replaced by the imide group :
CHgCONH, CH.CXNHJNHj.
Acetamide. Acetamidine.
They are produced :
(i ) From the imide chlorides and thiamides, by the action of ammonia or amines.
(2) From the nitriles by heating them with ammonium chloride.
(3) From the amides of the acids when treated with HC1 (B. 15, 208) :
] +CH8COaH.
(4) From the imido-ethers (p. 281) when acted on with ammonia and amines
(B. 16, 1647; 17,179).
The amidines are mono-acid bases. In a free condition they are very unstable.
The action of various reagents on them induces absorption of water, the imide
group splits off, and acids or amides of the acids are regenerated.
/3-Ketonic esters" con vert them into pyrimidines, e.g. acetamidine hydrochloride
and acetoacetic ester yield dimethyl ethoxypyrimidine, m.p. 192° (comp. polym.
acetonitrile, p. 280) :
H COCH8 N— Qr- CH8
+ ' =CH8Cf >CH +2H,O.
^NH2 CH2COOC2H. \N=C/- OC,H5
Formamidine (p. 244).
Aeetamidine, Acediamine, Ethenyl Amidine, CH3C(NH2)NH; hydrochloride,
m.p. 163°. The acetamidine, separated by alkalis, reacts strongly alkaline
and readily breaks up into NH8 and acetic acid.
16. HYDROXAMIC ACID'S,
These are produced by the action of hydroxylamine on acids, amides,
esters, and chlorides. They are characteiized by containing an oximido- or
AMIDOXIMES OR OXAMIDINES 283
isonitroso-group in place of a carboxylic oxygen atom (B. 22, 2854). Another
method of preparation is from aldehydes and nitrohydroxylamimc acids,
O:N(OH):N(OH) (C. 1901, II. 770).
CH3COH4-N203H2=CH3C(NOH)OH+HN02.
Benzene sulphohydroxamic acid, C6H6SO2NHOH, behaves similarly, by
forming acyl hydroxamic acids and benzene sulphinic acid, C,H6SO2H, with
aldehydes (C. 1901, II. 99).
They are crystalline compounds, acid in character, and form an insoluble
copper salt in ammoniacal copper solutions. Ferric chloride imparts a cherry-
red colour to both their acid and neutral solutions.
Acetohydroxamie Acid, CH3C(NOH)OH+£H2O, m.p. 59°. It dissolves very
easily in water and alcohol, but not in ether.
Formhydroxamic Acid (see p. 224).
17. HYDROXIMIC ACID CHLORIDES, RC<QO1
When chlorine is passed into a solution of acetaldoxime, a precipitate of
colourless crystals of Nitrosochlor ethane, CH3CH<NO, m.p. 65°, is formed. They
melt to form a blue liquid and dissolve in ether forming a blue solution. From
both the colour gradually disappears on standing owing to a change into Aceto-
hydroximic Acid Chloride, CHSC<QOH, m.p. —3°, a colourless, easily decomposed
liquid. Silver nitrate converts it into acetonitrolic acid (see below) ; chlorine
produces Nitrosodichlorethane, CH3CC12.NO, b.p. 68°, a deep blue oil (B. 35,
3101). Acetohydroximic acid chloride is also obtained directly by the action
of chlorine on a hydrochloric acid solution of acetaldoxime (B. 40, 1677).
18. NITROLIC ACIDS, R.C (P-
As these bodies are genetically related to the mononitroparaffins, they have
already been discussed immediately after them.
IQ. AMIDOXIMES or OXAMIDINES,
%
These compounds may be regarded as amidines, in which a H atom of the
amide or imide group has been replaced by hydroxyl. They are formed : by the
action of hydroxylamine on the amidines (p. 282) ; by the addition of hydroxyl-
amine to the nitriles (B. 17, 2746) :
CH3CN+NH2OH=CH3C<£g£,
Acetonitrile. Ethenyl Amidoxime.
and by the action of hydroxylamine on thiamides (B. 19, 1668) :
CH3CSNHa+NH2OH=CH3.C<*J**£+H2S.
The amidoximes are crystalline, very unstable compounds, which readily break
down into hydroxylamine, and the acid amides or acids.
Methenyl Amidoxime, Formamidoxime or Isouretine (p. 244).
Ethenyl Amidoxime, CH3C<^JH , m.p. 135°. Hexenyl Amidoxime, m.p.
48°. Heptenyl Amidoxime, m.p. 48-49° (B. 25, R. 637). Lauryl Amidoximet
m.p. 92-92-5°. Myristyl Amidoxime, m.p. 97°. Palmityl Amidoxime, m.p. 101*5—
102°. Stearyl Amidoxime, m.p. 106-106-5° (B. 26, 2844).
284 ORGANIC CHEMISTRY
20, 21. HYDROXAMIC OXIME (Hydroxyamido-oximes), NITROSOXIMES
(Nitrosolic Acids)
and allied bodies are obtained from the hydroximic acid chlorides and nitrolic
acids (A. 353, 65 ; B. 40, 1676). NHOH
Acetohydroxamie Oxime, Acetohydroxyamido-oxime, CHSC<NOH , results
from the interaction of acetohydroximic acid chloride and hydroxylamine, or
from the reduction of ethyl nitrolic acid (p. 153) with sodium amalgam. It is
unstable in the free state, but is known as a colourless hydrochloride, m.p. 156°,
with decomposition, and as a red brown copper salt, CtH4O2N2Cu+2H2O. Dilute
alkali changes it into an unstable strongly coloured axo-body, CH,C(:NOH).N
=N.C(:NOH)CH3, which partially changes into its more stable and equally
coloured isomer, azaurolic acid, CH3C(:NOH).NHN:C(NO)CH,, and partially
breaks down into ethyl nitrosolic acid and acetamide oxime :
CH,C(NOH).N=N.C(:NOH)CH3 — ^ CH,C(:NOH)NO+H2NC(NOH)CH8.
Acetonitroso-oxime, Ethyl Nitrosolic Acid, CH8C<^, is prepared from
acetohydroxamic oxime by oxidation with bromine. It is characterized by its
deep blue potassium salt, C2H3N2O2K. It is readily decomposed by acids.
For further reactions, see above.
22, 23. HYDRAZIDINE and HYDRAZO-OXIME,
such as RC<^HC«H« and RC<^Q^HC«H», see Vol. II., and B. 35, 3271.
24. ORTHO-FATTY ACID DERIVATIVES
The ortho-esters of the fatty acids are obtained similarly to orthoformic
ester (p. 244) (i) from the imido-ether hydrochlorides (p. 281) and alcohols
(B. 40, 3020) ; from the orthotrichlorides and sodium alcoholate ; (3) synthetically
from the orthocarbonic acid esters and alkyl magnesium halides (B. 38, 561).
Orthoacetic Triethyl Ester, CH3C(OC2H6)3, b.p.748 145°, b.p.13 42°, is a colour-
less pleasant -smelling liquid, but differing in odour from the ordinary ester.
Orthopropionic Ester, CH3CH2C(OC2H6)3, b.p.68 161°, b.p.12 54°. Ortho-
Acetyl Trichloride, Methyl Chloroform, Ethenyl Trichloride. i.i.i-Trichlorethane,
CHjCCl,, b.p. 74-5°, is formed together with i, i, 2, Trichlorethane, by the
action of chlorine on ethylidine chloride (A. 195, 183).
Methyl Nitroform, i,i,i-Trinitroethane is discussed with the nitroparaffins
(p. 156).
Orthoacetic Tripiperide, CH3.C(NC6H10)3, b.p. 261°, is obtained by heating
together methyl chloroform and piperidine. It forms a strongly alkaline, colour-
less liquid, of a peculiar odour : hydrochloride, CHa.C(N.C8H10.HCl)3, does not
melt at 260°.
HALOGEN SUBSTITUTION PRODUCTS OF THE FATTY ACIDS
The reactions leading to the substituted fatty acids are partly the
same as those employed in the formation of the halogen substitution
products of the paraffins.
(i) Direct substitution of the hydrogen of the hydrocarbon residue, joined to
carboxyl, by halogens.
(a) Chlorine in sunlight, or with the addition of water and iodine, or sulphur
(B. 25, R. 797), or phosphorus (B. 24, 2209) ; or by the action of sulphuryl
chloride on the fatty acids (C. 1905, I. 414).
(6) Bromine in sunlight, or with the addition of water in a closed tube at a
more elevated temperature, or with the addition of sulphur (B. 25, 3311), or
phosphorus (B. 24, 2209).
(c) Iodine with iodic acid, or bromo-fatty acids with potassium iodide.
HALOGEN SUBSTITUTION PRODUCTS OF FATTY ACIDS 285
The acid chlorides, bromides, or acid anhydrides are more readily substituted
than the free acids. This reaction can be brought about most suitably by the
addition of the required quantity of chlorine dissolved in CC14 to a solution of
the chloride in the same solvent. Each liquid is cooled externally, and the
mixture is made in full sunlight (B. 34, 4047). When chlorine or bromine, in the
presence of phosphorus, acts on the fatty acids (method of Hell- Volhard), acid
chlorides and bromides result ; these are then subjected to substitution. The
final products are halogen-acid chlorides or halogen-acid bromides :
3CH3.C02H+P+nBr=3CH2Br.COBr+HP03+5HBr.
However, substitution only takes place in a mono-alkyl or dialkyl-acetic
acid at the a-carbon atom. Hence, trimethylacetic acid cannot be chlorinated or
brominated. Consequently the behaviour of a fatty acid towards chlorine or
bromine and phosphorus indicates whether or not a trialkyl-acetic acid is
present (B. 24, 2209).
(2) Addition of Halogen Acids to Unsaturated Monocarboxylic Acids. — The
halogen enters at a point as far as possible from the carboxyl group, e.g. :
, HC1
( „„ > CH2C1.CH2.CO2H fl-Chloro- \
pTT •r'tr C~C\ Wl HBr
Acrylic Acid.2 j > CH2Br.CH2.CO2H j8-Bromo- jpropionic acid.
— >• CH2I.CH2.CO2H 0-Iodo- j
(3) Addition of Halogens to Unsaturated Monocarboxylic Acids. — Whenever
possible the chlorine is allowed to act in a CC14 solution. Bromine often reacts
without the help of a solvent, also in the presence of water, CS2, glacial acetic
acid and chloroform.
(4) Action of the halogen acids (a) on hydroxymonocarboxylic
acids :
CH2(OH)CH2COaH ^ CHaCl.CH2.C02H 0-Chloroproptonic
Lactic Acid : CH,CH(OH)CO2H -- > CH,CHBrCO2H a-Bromopropionic Acid.
Glyceric Acid : CH2(OH)CH(OH)CO2H -- > CHaI.CH2.CO2H
(46) On lactones, cyclic anhydrides of y- or 8-hydroxy acids :
HBr
CH2Br.CHa.CH2.COaH
2.a HI y-Biomobutyric Acid.
CH2.CO ^ \ - ; - > CH2I.CH2.CH2.CO2H
Butyrolactone y-Hydroxylbutyric y-Iodobutyric Acid.
Acid Lactone.
(5) Action of the phosphorus halides, particularly PC15, on hydroxy-
monocarboxylic acids or their nitriles (C. 1898, I. 22). The product
is the chloride of a chlorinated acid, which water transforms into the
acid :
CH8.CHOH.COOH+2PCl5=CH3.CHCl.COCl+2POCl3-f2HCl.
Lactic Acid. o-Chloropropionyl Chloride.
Furthermore, halogen fatty acids are obtained like the parent acids
(6) by the oxidation of chlorinated alcohols or aldehydes (p. 203) with
nitric acid, chromic acid, potassium permanganate or potassium
chlorate (B. 18, 3336) :
cory. CH,C1.CHC1.CH2OH -> CH.Cl.CHCl.CO.H
Chloral : CC1,CHO - ~ > CC13COOH M<Ato»cetic
286 ORGANIC CHEMISTRY
(7) By the action of halogen acids on diazo-fatty acid esters (see Glyoxylic
Acid) :
(8) When the halogens act on diazo-fatty acid esters :
Isomerism and Nomenclature. — Structurally, isomeric halogen sub-
stitution products of the fatty acids are first possible with propionic
acid. To indicate the position of the halogen atoms, the carbon
atom to which the carboxyl group is attached is marked a, whilst the
other carbon atoms are successively called j3, y, 8, e, etc. The two
monochloropropionic acids are distinguished as a- and j5-chloropro-
pionic acids, whilst the three isomeric dichloropropionic acids are the
aa-, pp- and aj8-dichloropropionic acids, etc.
Behaviour. — The introduction of substituting halogen atoms in-
creases the acid character of the fatty acids. The halogen fatty acids,
like the parent acids, yield, by analogous treatment, esters, chlorides,
anhydrides, amides, nitrites, etc.
On the velocity of ester formation and the electric conductivity
of the a-, j8-, y-, and 8-halogen fatty acids, see A. 319, 369.
Reactions. — (i) Nascent hydrogen causes the halogen substitution
products of the fatty acids to revert to the parent acids — retrogressive
substitution.
The reactions of the monohalogen fatty acids, which bear the same
relation to the alcohol acids or hydroxy-acids as the alkylogens do
to the alcohols, are especially important. In both classes the halogen
atoms enter the reaction under similar conditions.
(2) Boiling water, alkali hydroxides, or an alkali carbonate solu-
tion generally brings about an exchange of hydroxyl for the halogen
atom (A. 342, 115).
However, in monohalogen products, the position of the halogen atom, with
reference to carboxyl, will materially affect the course of the reaction : a-halogen
acids yield a-hydroxy acids, /Mialogen acids split off the halogen acid and become
converted into unsaturated acids with the formation also of jS-hydroxy acids
(A. 342, 127) ; y-halogen acids, on the contrary, yield y-hydroxy acids, which
readily yield lactones (B. 219, 322) :
H2O
CH2C1COOH - > CH2(OH)COaH
CHaClCH2COOH - - -- > CH2=CHCO2H
H20 ] — |
CH2ClCHaCH2COOH - >• CH2OCH2CH2CO.
(3) Ammonia converts the halogen fatty acids into amido-acids.
Nucleus-synthetic Reactions. — (4) Potassium cyanide produces cyano-
fatty acids— the mononitrile of dibasic acids, which hydrochloric acid
changes to dibasic acids. They will be considered after the latter :
KCN rr\ TT 2H.O.HC1
CH,C1CO,H - X:H2<«>2H - i__^ CH2<Cg*H
Chloracetic Add. Cyanacetic Acid. Malonic Ac2id.'
The monohalogen acids furnish a means of building up the dicarboxylic,
acids from the monocarboxylic acids.
HALOGEN SUBSTITUTION PRODUCTS OF FATTY ACIDS 287
(5) Dicarboxylic acids have been obtamde from mono-halogen carboxylic acids
by means of metals :
Adipic Acid.
(6) and (7) The esters of the mono-halogen fatt yacids have been applied in
connection with the acetoacetic ester and malonic ester syntheses, and as results
we have j3-ketone dicarboxylic acids, /3-ketone-tricarboxylic acids, and tri-
and tetracarboxylic acids.
(8) The esters of the halogen fatty acids can be changed into halogen zinc
or halogen magnesium fatty acid esters by means of the free metal ; in the
presence of aldehydes and ketones, salts of the higher hydroxy-fatty acid esters
are formed :
RCHO+BrCH(CH3)C02C2H6 - — - > RCH(OZnBr).CH(CH3)COaC2H5.
(9) The final product of condensation of a-halogen fatty acid esters and ketones
by means of sodium amide are the ethylene oxide carboxylic esters (glycidic acid
esters) :
NHaNa
RaCO+ClCH(CH8)COtC2Hs - > R2C— C(CH3)COaCaH».
O
Substitution Products of Acetic Acid.
Chlorine Substitution Products. — The relations of the three chloracetic acids to
the oxygen derivatives, whose chlorides they may be considered to be, are evident
in the following tabulation (comp. pp. 117, 206) :
MonochloraceticAcid, CH2C1CO2H, corresponds with Glycollic Acid, CH2OH.CO2H
Dichlor acetic Acid, CHC12CO2H, „ „ Glyoxylic Acid, CHO.CO2H
Trichlor acetic Acid, CC13CO2H, „ „ Oxalic Acid, COaH.COaH
Monochloraeetie Acid, CH2C1.CO2H, m.p. 62°, b.p. 185-187°, solidifies
after fusion to an unstable modification, m.p. 52°. This slowly reverts spon-
taneously to the ordinary acid (B. 26, R. 381). On the preparation of the acids
from acetic acid and sulphuryl chloride, see C. 1905, I. 414. Its sodium, and
silver salts, on the application of heat, yield poly gly collide.
When monochloracetic acid is heated with alkalis or water, the chlorine is
replaced by the hydroxyl group, and we get Hydroxy Acetic Acid or Glycollic
Acid (q.v.). Amino-acetic Acid, or Glycocoll, results when the monochlor-acid is
digested with ammonia.
The ethyl ester, b.p. i43'5°; chloride, b.p. 106°; bromide, b.p. 127°; anhydride,
m.p. 46°, b.p.n no0 (B. 27, 2949); amide, m.p. 116°, b.p. 224-225°; nitrite,
b.p. 124°.
Dichloracetic Acid, CHC12CO2H, b.p. 190-191°, is produced when chloral
is heated with potassium cyanide or ferrocyanide and some water. If alcohol
replace the water, dichloracetic esters are formed (B. 10, 2124) :
CCl3CHO+HaO + KCN=CHClaC02H+KCl+HCN.
When its silver salt is boiled with a little water, glyoxylic acid (q.v.) is pro-
duced. Methyl ester, b.p. 142-144° ; ethyl ester, b.p. 158° ; anhydride, b.p. 214-
216°, with decomposition ; chloride, b.p. 107-108° ; amide, m.p. 98°, b.p. 234° ;
nitrile, b.p. 113°.
Trichloracetic Acid, CC13CO2H, m.p. 55°, b.p. 195°, the officinal Acidum
trichloraceticum, was first prepared by Dumas (1839) when he allowed chlorine
to act in the sunlight on acetic acid (A. 32, 101). Without essentially changing
the chemical character, three hydrogen atoms of the acetic acid were replaced by
chlorine — a fact upon which Dumas then erected the type theory (p. 18). Kolbe
(1845) made the acid by the oxidation of chloral with concentrated nitric acid
288 ORGANIC CHEMISTRY
(A. 54, 183), and demonstrated how it could be prepared synthetically from its
C12 Heat CC12 Cla, 2HaO COOH.
C+2S > CSa > CC14 > j|
The carbon disulphide resulting from carbon and sulphur is converted by the
chlorine into carbon tetrachloride, which on the application of heat becomes
converted into perchlorethylene, CC12=CC12 (p. 97), and it, in turn, by the action
of chlorine and water, aided by sunlight, yields trichloracetic acid. This was
the first synthesis of acetic acid, for Melsens had previously shown that potassium
amalgam in aqueous solution reduced trichloracetic acid to acetic acid (p. 256).
Boiling with water decomposes trichloracetic acid into chloroform (p. 245)
and COj, whilst excess of alkali produces formic acid and a carbonate (A. 342,
122). Electrolysis gives rise to the formation of perchloracetic trichloromethyl
ester (C. 1897, II. 475).
The methyl ester, b.p. 152-5° ; ethyl ester, b.p. 164°, are obtained from
the acid and alcohols (B. 29, 2210 ; C. 1901, II. 1333). Trichloracetyl Chloride,
Perchloracetaldehyde, b.p. 118°, is formed when ozonized air or SO3 (A. 308, 324)
acts on perchlorethylene (B. 27, R. 509) (comp. synthesis of trichloracetic
acid from CSS) ; bromide, b.p. 143° ; anhydride, b.p. 224° ; amide, m.p. 141°,
b.p. 239° ; nitrile, b.p. 83°. Perchloracetic Trichloromethyl Ester, CC13.CO2CC13,
m.p. 34°, b.p. 192° (A. 273, 61).
Bromacetic Acids. — Monobromacetic Acid, CHaBr.CO2H, m.p. 50-51°, b.p.
208° ; ethyl ester, b.p. 159° ; chloride, b.p. 134° ; bromide, CH2Br.COBr, b.p. 150°
(pp. 98, 270) ; anhydride, b.p. 245° ; amide, m.p. 91° ; nitrile, b.p. 148-150°
(B. 38, 2694).
Dibromacetic Acid, C2H2Br2O2, m.p. 54-56°, b.p. 232-235° ; ethyl ester,
b.p. 192° ; bromide, CHBr2.COBr (pp. 98, 270), b.p. 194° ; amide, m.p. 156°
(B. 38, 2695).
Tribromacetic Acid, CBr8CO2H, m.p. 135°, b.p. 246° with decomposition,
results from the interaction of perbromethylene and nitric acid (A. 308, 324).
Boiling water or alkali decomposes it similarly to trichloracetic acid (see above).
Ethyl ester, b.p. 225° ; bromide, b.p. 220-225° ; amide, m.p. 120-121°; nitrile, b.p.
170°, is a dark red liquid, which HC1 changes to the polymeric trinitrile, m.p.
129° (B. 27, R. 730).
lodoacetic Acids. — Moniodoacetic ^c*J,CH2ICO2H, m.p. 82° (C. 1901, I. 665).
Di-iodoacetic Acid, CHI2.CO2H, m.p. 110°.
Tri-iodoacetic Acid, m.p. 150°. The last two compounds have been obtained
from malonic acid and iodic acid (B. 26, R. 597). (Comp. iodoform, p. 246.)
FlupracetiC Acids.— Monoftuor acetic Acid, CH2F.COOH, m.p. 33°, b.p. 165°,
is obtained by the hydrolysis of its methyl ester, b.p. 104°, which in turn is prepared
from methyl iodo-acetate and mercury or silver fluoride. Difluoracetic acid,
CHFjCOOH, b.p. 134°, is prepared by oxidation of difluorethyl alcohol (from
difluor-ethyl bromide). In these compounds the fluorine atom is held relatively
firmly in the molecule (J. 1896, 759 ; C. 1903, II. 709). Dibromofluoracetic
acid, CBr?F.COOH, m.p. 26°, b.p. 198° ; ethyl ester, b.p. 173°, possesses a
camphor-like odour ; fluoride, CBr2F.COF, b.p. 75°, is formed from symmetrical (?)
dibromodifluorethylene by the absorption of oxygen (C. 1898, II. 702).
Substitution Products of Propionic Acid.
The a-monohaloid propionic acids contain an asymmetric carbon atom ;
hence their esters, for example, are known in an active form. They are prepared
according to the methods 4*1 and 5 (p. 285). The jS-monohalogen acids are derived
from acrylic acid by method 3 (p. 285), and j8-iodopropionic acid from glyceric
acid by method 40.
a-Chloropropionic Acid, CH3CHC1CO2H, b.p. 186°; ethyl ester, b.p. 146 ;
chloride, 109-110°; amide, 80°; nitrile, b.p. 121-122°, is prepared from
acetaldehyde cyanohydrin and PC15 (B. 34, 4049). a-Bromopropionic Acid,
m.p. 24-5°, b.p. 205°, is resolved into its optically active components by cinchonine;
ethyl ester, b.p. 162° ; bromide, b.p. 153° (A. 280, 247) ; anhydride, b.p.5 120°
(B. 27, 2949). Dextro-rotatory a-Chloro- and a-Bromopropionic esters are
obtained from sarcolactic acid (B. 28, 1293). a-Iodopropionic Acid, m.p. 45°,
is prepared from propionyl chloride and iodine chloride (B. 36, 4392).
0-ChloropropIonIc Acid, CH2C1CH2CO,H, m.p. 41-5°. b.p. 203-204°; methyl
HALOGEN SUBSTITUTION PRODUCTS OF FATTY ACIDS 289
ester, b.p. 156° ; ethyl ester, b.p. 162° ; chloride, b.p. 143-135°. jS-Bromopro-
pionic Acid, m.p. 61-5°; ethyl ester, b.p.10 69-70°; bromide, b.p. 154-155°.
J9-Iodopropionie Acid, m.p. 82° ; methyl ester, b.p. 188° ; ethyl ester, 202° ;
amide, m.p. 100° (B. 21, 24, 97), is formed by boiling the ester with sodium
amalgam and subsequently hydrolyzing the mercury dipropionic acid, Hg(CH2-
CH2COOH)2 formed, consisting of prisms, which are only slightly poisonous.
The aqueous solution, when boiled, deposits a heavy precipitate of hydroxy-
mercury propionic anhydride, OHgCH2CH2CO (B. 40, 386).
Dihalogen Propionie Acids. — oa-Acids are prepared by the chlorination
and bromination of propionic acid (B. 18, 235) ; ajS-acids, by the addition of
chlorine and bromine to acrylic acid, by the addition of a halogen acid to
a-halogen acrylic acids, and by the oxidation of the corresponding alcohols
(p. 285) ; $8-acids, by the addition of a halogen acid to ^-halogen acrylic
acids.
aa-Dichloropropionic Acid, CH3CClaCO2H, b.p. 185-190° ; ethyl ester, b.p.
156-157° ; chloride, from pyroracemic acid and PC16, b.p. 105-115°, amide,
m.p. 116° (B. 11, 388) ; nitrile, b.p. 105° (B. 9, 1593).
The silver salt changes to pyroracemic acid when heated in aqueous solution,
and aa-dichloropropionic acid.
aa-Dibromopropionic Acid, m.p. 61°, b.p. 220°; ethyl ester, b.p. 190°, is
decomposed by sodium hydroxide into pyroracemic acid, CH3COCOOH, and
bromacrylic acid (A. 342, 130).
afi-Dichloropropionic Acid, CH2C1CHC1CO2H, m.p. 50°, b.p. 210° ; ethyl
ester, b.p. 184°.
afi-Dibromopropionie Acid, m.p. 51° and 64°, b.p. 227° with partial decom-
position, is capable of existing in two allotropic modifications, which can be
readily converted one into the other, and of which the more stable possesses
the higher melting point. Water or sodium hydroxide produces from it a-bromo-
acrylic and glyceric acids (A. 342, 135): ethyl ester, b.p. 211-214°.
fiB-Dibromopropionic Acid, m.p. 71°, is formed from j8-bromacrylic acid and
HBr (B. 27, R. 257).
Substitution Products of the Butyric Acids.
a-Chloro-n-butyric Acid, CH8CH2CHC1CO2H, b.p.]B 101° (A. 319, 358), is a
thick liquid: ethyl ester, b.p. 156-160°; chloride, b.p. 129-132°, is obtained
from butyryl chloride (A. 153, 241) ; nitrile, b.p. 142°.
a-Bromobutyric Acid, b.p. 215°, is prepared from butyric acid.
fi-Chloro-n-butyric Acid, CH3CHC1.CH2COOH, b.p.12 99°, is obtained from
allyl cyanide, and from solid crotonic acid and HC1 ; nitrile, b.p. 175°.
fi-Bromo-n-butyric Acid, m.p. 18°, b.p.16 122°, and fi-Iodo-n-butyric Acid,
m.p. 110° (B. 22, R. 741 ; C. 1905, I. 24) have been obtained from crotonic acid
and from allylcyanide.
y-Chloro-n-butyric Acid, CHaClCH2CHaCOaH, m.p. 16°, b.p.13 115°, is
obtained from the nitrile and from trimethylene carboxylic acid and HC1 (A. 319,
363). Trimethylene chlorobromide, CH2Cl.CH2CH2Br and KCN yield y-Chloro-
butyric Nitrile, b.p. 189° (A. 319, 360). Alkali hydroxides convert the nitrile into
trimethylene carboxylic acid nitrile (Vol. II.) (C. 1908, I. 1357). The acid is
obtained from this, and when distilled at 200° it yields HC1 and butyrolactone.
y-Bromo- and y-Iodobutyric acids, m.p. 33° and 41°, result from butyro-
lactone (q.v.) by the action of HBr and HI (B. 19, R. 165).
ap-Dichlorobutyric Acid, CH3CHC1CHC1CO2H, m.p. 63°. ap-Dibromo-
butyric Acid, m.p. 85°. Both are obtained from crotonic acid (p. 295). fi-y-Di-
bromobutyric Acid is obtained from vinyl acetic acid (p. 297).
aap-TricMorobtityric Acid, CH3.CHC1.CC12.CO2H, m.p. 60°, appears in the
oxidation of trichlorobutyraldehyde and by the action of chlorine on
chlorocrotonic acids (B. 28, 2661).
aap-Tribromobutyric Acid, m.p. 115°. The solutions of the sodium salts of
both acids break down, when warmed, into CO2, sodium halide, and ao-dichloro-
and aa-dibromopropylene (B. 28, 2663).
a-Bromisobutyric Acid (CH3)2CBr.COOH, m.p. 48°, b.p. 199 ,* ethyl ester,
b.p. 164° ; anhydride, m.p. 63° (B. 27, 2951) ; amide, m.p. 148°, with bromine
and alkali (comp. p. 277) yields acetone (C. I9°5. I. 1220).
a-Bromisobutyryl Bromide, b.p. 163°, is converted by zinc in ethereal or
VOL. i. y
29o ORGANIC CHEMISTRY
ethylacetate Dimethyl Ketene, (CH,)2C:CO. This is a wine-yellow liquid, boiling
at a low temperature, which polymerizes at ordinary temperatures to tetramethyl
diketo-cyclobutane [(CH8)aC.CO]s. It is also obtained from isobutyryl chloride
(v 271) and trimethylamine. Water, alcohol, and amlme unite with the
ketone to form isobutyric acid, ester, and anilide respectively (B. 39, 968).
a-Iodobutyric Acid, m.p. 73° (C. 1900, I. 960), is prepared from isobutyryl
chloride, SaCla, and iodine.
Halogen Substitution Products of the Higher Fatty Acids.
Acids containing the group (CH3)2CH, have their methine hydrogen sub-
stituted by chlorine when the reaction takes place in sunlight at 100° (C. 1897,
II. noo; 1899, II. 963). Among the higher members some a-bromo-acids are
prepared' by br'omination with or without the presence of phosphorus (B. 25,
486). Such compounds can also be obtained by the addition of the halogen acids
or the halogen to unsaturated acids (A. 319, 357 ; C. 1901, I. 93. 665). Dialkyl
bromacetic acids, RaCBrCOOH, can also be prepared from dialkyl malonic acid
by heating with bromine and water. Some of their amides are employed as
soporofics (C. 1906, II. 1694).
The dibromo-addition-products of the unsaturated acids have been exhaus-
tively studied. Water almost invariably sets the COOH free from the aj8-dibro-
mides with the formation of brominated hydrocarbons, etc., whereas carbon is
never split off from the j3y- and y8-derivatives, but the first products are bromi-
nated lactones, from which hydroxy-lactones and y-ketonic acids are simul-
taneously obtained (A. 268, 55).
B. OLEIC ACIDS, OLEFINE MONOCARBOXYLIC ACIDS,
CnH 2M - jCO 2H
The acids of this series, bearing the name Oleic Acids because
oleic acid belongs to them, differ from the saturated fatty acids by
containing two atoms of hydrogen less than the latter. They also
bear the same relation to them that the alcohols of the allyl series do
to the normal alcohols. We can consider them as being derivatives
of the alkylens, CnH2n, produced by the replacement of one atom of
hydrogen by the carboxyl group.
Some of the methods employed for the preparation of the un-
saturated acids are similar to those used with the saturated acids.
Others correspond with the methods used with the olefines, and
others, again, are peculiar to this class of bodies.
From compounds containing a like carbon content :
(1) Like the saturated fatty acids, they are produced by the oxida-
tion of their corresponding alcohols and aldehydes ; thus, allyl alcohol
and its aldehyde afford acrylic acid :
CH2:CH.CH2OH > CH2:CH.CHO > CH2:CH.CO2H.
Allyl Alcohol. Acroleln. Acrylic Acid.
(2) by the action of alcoholic potassium hydroxide (p. 286) on
the monohalogen derivatives of the fatty acids, or by the action of
heat on them, together with a tertiary base such as diethyl aniline
or quinoline (C. 1898, I. 778).
CH3.CH2.CHC1.C02H and CHS.CHC1.CH8.CO2H yield CHS.CH:CH.CO,H
•-Chlorobutyric Acid. /3-Chlorobutyric Acid. Crotonic Acid.
The fl-derivatives are especially reactive, sometimes parting with halogen
acids when boiled with water (p. 286) ; whereas the y-halogen acids yield
hydroxy-acids and lactones. (3) Similarly, the ajS-derivatives of the acids (p. 289)
readily lose two halogen atoms, (a) either by the action of nascent hydrogen—
CH4Br.CHBr.COaH+2H=CH2:CH.CO2H-f2HBr,
«£-Dibromopropionic Acid. Acrylic Acid.
OLEIC ACIDS, OLEFINE MONOCARBOXYLIC ACIDS 291
or (b) even more readily when heated with a solution of potassium iodide, in which
instance the primary di-iodo-compounds part with iodine (p. 136) :
CHaI,CHLCOaH=CH2:CH.COaH+Ia.
(4) by the addition of hydrogen to acetylene carboxylic acids :
CH3.C ! C.COOH+2H=CH3.CH:CH.COOH.
Tetrolic Acid. Crotonic Acid.
(5) by the removal of water (in the same manner in which the
alkylens CnH2n are formed from the alcohols) from the hydroxy-fatty
acids (the acids belonging to the lactic series) :
CH3CH(OH).C02H and CH2(OH).CH2.CO2H yield CH2:CH.CO2H.
a-Hydroxypropionic Acid. /3-Hydroxypropionic Acid. Acrylic Acid.
Here again the ^-derivatives are most inclined to alteration, losing water when
heated. The removal of water from a-derivatives is best accomplished by treating
the esters with PC13. The esters of the unsaturated acids are formed first, and
can be saponified by means of alkalis. Another method is to act with P2O5
on the nitriles of the hydroxy-acids (C. 1898, II. 662). £-Hydroxy-acids also
yield olefine carboxylic acids when boiled with alkalis (A. 283, 58).
If both a-situated hydrogen atoms in a /?-hydroxy-acid are substituted, warming
the ester with P2O6 causes elimination of water in the /?y position ; if, however,
there is no hydrogen in the y position, an informal rearrangement occurs which
favours the expulsion of water (C. 1906, II. 317, 318):
-H2o
CH3CH(OH)Q(£H3)C02R - > CH2:CHC(CH3)2COaR
CH2(OH)C(CH3)2C02R > CH(CH3):C(CH8)COaR.
(6) Amino-fatty acids lose the amino-group, after previous methylation,
and yield olefine carboxylic acids (B. 33, 1408).
(7) a-alkyl a-bromethylene succinic acids lose HBr and COa when boiled
with sodium hydroxide (C. 1899, 1. 1071).
Nucleus-synthetic Methods. — (8) Some may be prepared syntheti-
cally from the halogen derivatives, CnH2n-iX, through the cyanides
(p. 252) ; thus, allyl iodide yields allyl cyanide and crotonic acid, and
the position of the double bond is changed :
CH2=CHCH2I - — >• CH2:CH.CHaCN - > CH3CH=CHCO2H.
The replacement of the halogen by CN in the compounds CJE^^X is con-
ditioned by the structure of the latter. Although allyl iodide, CH2:CH.CH,I,
yields a cyanide, ethylene chloride, CHa:CHCl, and /3-chloropropylene, CH3.-
CC1:CH2, are not capable of this reaction.
(9) The action of CO2 and magnesium on an ethereal solution of allyl bromide
produces vinyl acetic acid (B. 36, 2897) :
CH2:CHCH2Br+Mg+COa=CH2:CHCH2COOMgBr.
(10) Some acids have been synthetically prepared by Perkin's reaction, which
is readily brought about with benzene derivatives, but proceeds with difficulty
in the fatty series. It consists in treating the aldehydes with a mixture of acetic
anhydride and sodium acetate (comp. Cinnamic Acid) :
C6H13CHO4-CHa.COaNa=C,H18CH:CH.CO2Na+HaO.
(Enanthol. Nonylcnic Add.
(A. 277, 79 ; C. 1899, I. 595-)
j3-Dimethyl acrylic acid is obtained from acetone, malonic acid and acetic
anhydride (B. 27, 1574).
Pyroracemic acid acts analogously with sodium acetate — carbon dioxide
splits off and crotonic acid results (B. 18, 987).
2Q2 ORGANIC CHEMISTRY
Methods of formation, dependent upon the breaking-down of long
carbon chains :
(n) by the decomposition of unsaturated fi-ketonic acids, synthetically pre-
pared by the introduction of unsaturated radicals into acetoacetic esters. Allyl
acetoacetic ester yields ally I acetic acid (p. 299).
(12) by the decomposition of unsaturated malonic acids, containing the two
carboxyl groups attached to the same carbon atom (p. 253) :
CH8.CH:C(C02H)2 = CH,.CH:CH.CO2H+COr
Etbylidene Malonic Acid. Crotonic Acid.
(13) Unsaturated /?y-acids are prepared by distilling y-lactone-/3-carboxylic
acids, the alkylated paraconic acids (B. 23, R. 91). In the same manner yS-un-
saturated acids result from the 8-lactone-y-carboxylic acids (B. 29, 2367) :
9°*H -co, y jB a
MM pa« CH3-CH.CH.CHa - > CH3CH:CH.CH2.CO2H
conic AcS^ o _ CO Ethylidene-propionic Acid
9°*H 8 y ft a
a-Caprolactone- CH,.CH.CH.CH1.CH1 - > CH3.CH:CH.CH2.CH2.CO,H.
y-carboxylic Acid, * _ ' yfi-Hexenic Acid.
Isomerism. — An isomer of acrylic acid is neither known nor possible.
The second member of the series has three structurally isomeric, open-
carbon chain modifications :
(i) CH,.CH=CH.CO,H; (2) CHa=CH.CH,.CO2H ; (3) CH,=C<£^H.
In fact, there are three crotonic acids — the ordinary solid crotonic
acid, isocrotonic acid and methyl acrylic acid. Formerly, formula 2
was ascribed to isocrotonic acid. There is, however, considerable
support for the view that both acids — the ordinary solid crotonic acid
and isocrotonic acid — have the same formula. Hence it is assumed
that crotonic and isocrotonic acids are merely geometric, stereo- or
space-isomers. (Comp. crotonic acids, p. 295.)
Numerous pairs of isomers, whose differences may be similarly
indicated, resemble crotonic and isocrotonic acids — angelic and tiglic
acids ; oleic and elai'dic acid ; erucic and brassidic acids.
The monocarboxylic acids of tri-, tetra-, penta-, and hexamethy-
lene are structurally isomeric with the acids C3H5.CO2H, C4H7CO2H,
C5H9CO2H, C6HnC02H. Further, the trimethylene carboxylic acid,
- 2/>CH.C02H, is isomeric with the three crotonic acids, and
v/ttj'
tetramethylene carboxylic acid, CH2<£**2^>CHCO2H, etc., with the
acids C4H7CO2H. (Comp. p. 80.)
Properties and Reactions. — Like the saturated acids in their
entire character, the unsaturated derivatives are, however, dis-
tinguished by their ability to take up additional atoms : they unite
the properties of a fatty acid with those of an olefine.
(i) On combining with two hydrogen atoms they become con-
verted into saturated fatty acids.
Most of the lower members combine readily with the H2 evolved in the action
of zinc on dilute sulphuric acid, whilst the higher remain unaffected. Sodium
OLEIC ACIDS, OLEFINE MONOCARBOXYLIC ACIDS 293
amalgam apparently only reduces those acids in which the carboxyl group is
in union with the doubly-linked pair of carbon atoms (B. 22, R. 376). All may
be hydrogenized, however, by heating with hydriodic acid and phosphorus.
(2) Esters of the unsaturated acids, such as acrylic and crotonic
acids, polymerize under the influence of sodium methoxide, whereby
the double bond is broken, and the j3-carbon atom of one molecule
joins the a-carbon atom of a second, accompanied by a compensating
wandering of a hydrogen atom :
2CH2:CH.COOH = CO2H.C(:CH2).CH2.CHa.COOH.
(3) They combine with halogen acids, forming monohalogen
fatty acids. In so doing the halogen atom enters the molecule as
far as possible from the carboxyl group (p. 285).
(4) They unite with the halogens to form dihalogen fatty acids
(P. 285).
All these reactions have already been given as methods for forming
fatty acids and their halogen derivatives.
(5) Ammonia converts the olefine carboxylic acids into amino-fatty acids:
crotonic acid yields /J-aminobutyric acid. Hydrazine and phenylhydrazine
behave similarly with the same compounds.
(6) Diazoacetic ester and diazomethane combine with the olefine carboxylic
esters to produce pyrazoline carboxylic ester ; acrylic ester and diazoacetic
ester yield 3,4-pyrazoline carboxylic ester (q.v.) (Buchner, A. 273, 222).
(7) The olefine carboxylic acids unite with NaO4, forming nitriles of the
nitrohydroxycarboxylic acids (C. 1903, II. 554 ; 1904, I. 260) :
Na04
CH8CH:CHCOOH > CH,CH(ONO).CH.(NO,)COOH.
(8) The behaviour of unsaturated acids towards alkalis is espe-
cially noteworthy.
(a) When heated to 100°, with KOH or NaOH, they frequently absorb the
elements of water and pass into hydroxy acids. Thus, from acrylic acid we obtain
a-lactic acid, CH2:CH.CO2H+HaO=CH8.CH(OH).CO2H.
(6) /Jy-Unsaturated acids rearrange themselves to ajS-unsaturated acids (Fittig,
A. 283, 47, 269 ; B. 28, R. 140) when they are boiled with alkali hydroxide ; the
double union is made to take a new position :
CH3.CHa.(?H=CH.CHa.COOH > CH8.CH2.<*H2.CH=CH.COOH.
Hydrosorbic Acid. n-Butylidene Acetic Acid.
(c) When fused with potassium or sodium hydroxide their double
union is severed and two monobasic fatty acids result :
CHa:CH.COjH+2HaO=CH8O2+CH,.COjH4-H1.
Acrylic Acid. Formic Acid. Acetic Acid.
CH3CH:CH.COaH+2HaO=CH3.C02H+CHs.C02H+Ht.
Crotonic Acid. Acetic Acid. Acetic Acid.
The decomposition occasioned by fusion with alkalis is not a reaction
which can be applied in ascertaining constitution, because under the
influence of the alkalis there may occur a displacement or rearrange-
ment of the double union.
(9) Oxidizing agents like chromic acid, nitric acid and potassium permanganate
have the same effect as alkalis, (a) The group linked to carboxyl is usually
further oxidized, and thus a dibasic acid results.
294 ORGANIC CHEMISTRY
(b) When carefully oxidized with permanganate, the unsaturated acids
undergo an alteration similar to that of the defines ; dihydroxy acids result
(Fittig, B. 21, 1887).
CH3.CH:C(C2H6)COsH-r-O+H,O=CH8CH(OH)— C(OH)(C2H6)C02H.
o-Ethyl Crotonic Acid. a-Ethyl /3-Methyl Glyceric Acid.
(10) Ozone produces ozonides by action on the olefine carboxylic
acids. They are decomposed by water into aldehydes and aldehyde-
acids, a reaction which indicates their constitution (comp. p. 84)
(A. 343, 34) :
3 + H2O=CH8CHO+HOC.COOH+H8Oai
Crotonic or Isocrotonic Acid. Acetaldehyde. Glyoxylic Acid.
(n) j8y-Unsaturated acids when heated with dilute sulphuric acid
yield y-lactones :
(CH3)2C:CH.CH2C02H - > (CH3)2C.CH2.CH2.COO
Pyroterebic Acid. Isocaprolactone.
i. Acrylic Acid [Propene-Acid], CH2:CH.CO2H, m.p. 7°, b.p. 141°,
is obtained according to the general methods :
(i) From j3-chloro-, j3-bromo-, or /J-iodo-propionic acid by the
action of alcoholic potassium hydroxide or lead oxide.
(z) From ajS-dibromopropionic acid by the action of zinc and
sulphuric acid, or potassium iodide, or reduced copper containing
iron (C. 1900, II. 173).
(3) By heating J3-hydroxy propionic acid (hydracrylic acid).
The best method consists in oxidizing acrolein with silver oxide, or
by the conversion of acrolein, by successive treatment with hydro-
chloric and nitric acid, into j8-chloropropionic acid, and the subse-
quent decomposition of this acid by alkali hydroxide (B. 26, R. 777 ;
B. 34, 573).
Acrylic acid is a liquid with an odour like that of acetic acid, and
is miscible with water. If allowed to stand for some time, it is trans-
formed into a solid polymer. By protracted heating on the water-
bath with zinc and sulphuric acid it is converted into propionic acid, a
reaction which does not occur in the cold. It combines with bromine
to form ap-dibromopropionic acid, and with the halogen acids to
yield ft- substitution products of propionic acid (p. 288). If fused with
alkali hydroxides, it is broken up into acetic and formic acids.
The silver salt, C3H3O2Ag, consists of shining needles ; lead salt, (C8H3O2)2Pb,
crystallizes in long, silky, glistening needles; et\yl ester, C8H3O2.C2H5, b.p. 101°,
obtained from the ester of a/?-dibromopropionic acid by means of zinc and sulphuric
acid, is a pungent-smelling liquid ; methyl ester, b.p. 85°, is polymerized by
sodium methyoxide to a-methylene glutaric ester (B. 34, 427).
Acryl chloride, CH2:CH.COC1, b.p. 75°; anhydride [CH2:CH.CO]2O, b.p.35
97°; amide, CH2:CH.CONH2, m.p. 84° ; nitrile, vinyl cyanide, CH2:CH.CN, b.p.
78° (B. 26, R. 776 ; C. 1899, II. 662).
Substitution Products. — There are two isomeric forms of mono- and di-sub-
stituted acrylic acids.
a-Chhracrylic Acid, CH2:CC1.CO2H, m.p. 64°, results when a/?- and also
aa-dichloropropionic acids are heated with alcoholic potassium hydroxide. It
combines with HC1 at 100° to produce ajS-dichloropropionic acid (B. 10, 1499;
18, 244).
p-Chloracrylic Acid, CHC1:CH.CO2H, m.p. 84°, is produced together with
dichloracrylic acid in the reduction of chloralide with zinc and hydrochloric acid
OLEIC ACIDS, OLEFINE MONOCARBOXYLIC ACIDS 295
(A. 203, 83 ; 239, 263), also from propiolic acid, C3H2O2 (p. 303), by the addition
of HC1. It unites with HC1 to j6/?-dichloropropionic acid ; ethyl ester, b.p. 146°.
a-Bromacrylic Acid, m.p. 69-70°, is slowly decomposed by alkalis into
acetylene, alkali bromide, and bicarbonate (A. 342, 135).
p-Bromacrylic Acid, m.p. 115-116°.
B-Iodoacrylic Acid, is known in two modifications, m.ps. 139-140° and 65"
(B. 19, 542).
aB-Dichloracrylic Acid, m.p. 87° ; fifi-Dichloracrylic Acid, m.p. 76-77°.
afi-Dibromacrylic Acid, m.p. 85-86°; Pfi-Dibromacrylic Acid, m.p. 86°.
ap-Di-iodo-acrylic Acid, m.p. 106° ; fifi-Di-iodo-acrylic Acid, m.p. 133°
(B. 18, 2284).
a-Chlor-p-iodo-Acrylic Acid, m.p. 89°, results from reduction of lodoso-
chlor acrylic Acid, or I odosochloro-chlor acrylic A cid, which in turn is prepared
by the action of water or alcohol on iodosochloro-chlorofumaric acid (B. 38,
2842):
C1IC(COOH):CC1.COO - > C1ICH:CC1.COO -- > ICH.CC1COOH.
lodosochloro-chloro- lodosochloro Chloro-iodo-
fumaric Acid. chloracrylic Acid. acrylic Acid.
Trichloracrylic Acid, m.p. 76° ; ethyl ester, b.p. 193° ; orthoethyl ester,
CC12:CC1C(OC2H6)3, b.p. 236°, from hexachloropropylene (A. 297, 312).
Tribromacrylic Acid, m.p. 117-118°.
2. Crotonic Acids, C3H5.C02H.
In the introduction to the olefine carboxylic acids the isomerism
of the crotonic acids was made evident, and it was shown that the
difference between crotonic and isocrotonic or quartenylic acid de-
pended on the different arrangement of the atoms in the molecules
of the two acids, in the sense of the following formulae (A. 248, 281} :
HCCOaH HC.C02H
HC.CH, CH8CH
(Plane Symmetric Config.) (Axial Symmetric Conflg.)
Which of the two formulae may be assigned to the ordinary solid
crotonic acid, and which to the lower melting isocrotonic acid has not
yet been determined with certainty, although there has been no dearth
of investigations to place the matter on experimental and theoretical
bases (B. 25, R. 855, 856 ; 26, 108 ; 29, 1639 i 34, 189 ; 38, 2534 ;
A. 268, 16 ; 283, 47 ; C. 1897, II. 159 ; J. pr. Ch. [2] 46, 402 ; 75,
105 ; Z. phys. Ch. 48, 40).
In the following table of the crotonic acids and their halogen sub-
stitution products, the plane-symmetrical or cis- configuration has been
arbitrarily assigned to crotonic acid, and the axial-symmetrical or
cis- trans (pp. 34, 35) formula to isocrotonic acid.
(i ) Crotonic Acid CI^|>C:C<^°2H m.p. 72°; b.p. 1 80°.
(ia) a-Chlorocrotonie Acid CI*|>C:C<£p2H „ 99° ; „ 212°.
(ib) 0-Chloroerotonie Acid ^CrCX0*11 „ 94° ; „ 200°.
(ic) a-Bromocrotonic Acid C:C<£8 „ 106°.
(id) 0-Bromoerotonic Acid CgJ>C:C<^°aH „ 95°.
(2) Isocrotonic Acid ^^0*1* " I5° ; » 75°
296 ORGANIC CHEMISTRY
TT PO TT
(20) a-Chlorisocrotonic Acid CH3>C:C<C1 * m'p' 66°'
(26) jS-Chlorisocrotonic Acid CH3>C:C<H°aH " 59° ; b'p< I95°*
(2c) a-Bromisocrotonic Acid CH >C:C<Br * „ 92°.
i. Ordinary Crotonic Acid is obtained according to the general
methods of formation (pp. 290, 292) :
(1) by the oxidation of crotonaldehyde, CH3CH : CHCON (p. 215) ;
(2) by the action of alcoholic potassium hydroxide on a-bromo-
butyfic acid and fi-iodobutyric acid ;
(3) by the action of KI on afi-dibromobutyric acid;
(4) by the distillation of fi-hydroxybutyric acid ;
(5) by the hydrolysis of allyl cyanide, CH2 : CHCH2CN, produced
by alkyl iodide and potassium cyanide, accompanied by an internal
rearrangement (B. 21, R. 494 ; C. 1903, II. 657).
(6) The most practicable method of obtaining crotonic acid is to
heat malonic acid, CHgCCC^H^, with paraldehyde and acetic anhy-
dride : the ethylidene malonic acid first produced decomposes into
C02 and crotonic acid (p. 291) (A. 218, 147) ;
(7) Finally, from isocrotonic acid, dissolved in water or carbon
bisulphide, by the action of a trace of bromine, in sunlight.
Crotonic acid crystallizes in fine, woolly needles or in large plates,
and dissolves in 12 parts water at 20°. The warm aqueous solution
reduces alkaline silver solutions with the formation of a silver mirror.
Zinc and sulphuric acid, but not sodium amalgam, convert it into
normal butyric acid. It combines with HBr and HI to yield j3-bromo-
and j3-iodobutyric acid, and with chlorine and bromine to form
a^-dichloro- and a/3-dibromobutyric acids. Its methyl ester com-
bines at 180° with sulphur (B. 28, 1636). It polymerizes under the
influence of sodium ethoxide to form a-ethylider.e /2-methyl glutaric
ester (B. 33, 3323). Crotonic ethyl ester, similarly treated, yields
j8-ethoxybutyric ester (B. 33, 3329). When fused with potassium
hydroxide, it breaks up into two molecules of acetic acid ; nitric acid
oxidizes it to acetic and oxalic acids, and potassium permanganate
to dihydroxybutyric acid (A. 268, 7), Similarly to isocrotonic acid,
crotonic aciol is split up by ozone and water into acetaldehyde and
glyoxylic acid (p. 294).
Methyl ester, b.p. 121°; chloride, b.p. 114° (B. 34, 191); anhydride, b.p.19
128-130°, from crotonic acid and acetic anhydride, gives, with BaO2, crotonyl
peroxide (CHjCHiCHCO)^, m.p. 41 (C. 1903, I. 958).
(ifl) a-Chloroerotonic Acid, CH3.CH:CCl.COaH, is obtained when trichloro-
butyric acid (p. 289) is treated with zinc and hydrochloric acid, or zinc dust and
water; also, by the action of alcoholic potassium hydroxide on aS-dichloro-
butyric ester (B. 21, R. 243).
(16) /J-CSiUroerotonie Acid, CHa.CCl:CH.CO2H, is obtained in small quantities
(together with £-chlorisocrotonic acid) from acetoacetic ester, and by the addi-
tion of HC1 to tetrolic acid. With boiling alkalis it yields tetrolic acid (p. 304).
Sodium amalgam converts both a- and j8-chlorocrotonic acids into ordinary
crotonic acid.
^Chlorocrotonic acid, CH2C1.CH:CH.CO2H, m.p. 77°, from the nitrile, b.p.1§
73 , which is prepared by distilling the addition product of HNC and epichlor-
hydnn with PaO§ (C. 1900, II. 37).
OLEIC ACIDS, OLEFINE MONOCARBOXYLIC ACIDS 297
(ic) fl-Bromocrotonie Acid is prepared from the ester of dibromobutyric acid.
(id) jS-Bromoerotonie Acid is produced from tetrolic acid.
Dichloro- and Dibromoerotonie Acids. (See Tetrolic Acid, p. 304.)
(2) Isoerotonic Acid, Quartenylic acid, Cis-trans Crotonic Acid, Allocrotonic
Acid, m.p. 15°, was first obtained from ^3-chlorisocrotonic acid by means of
sodium amalgam, and results also from a-chlorisocrotonic acid. It is also formed
by distilling /2-hydroxyglutaric acid under reduced pressure (C. 1898, II. ion).
Heated in a closed tube to 170-180°, it is converted into crotonic acid, a change
which also partially occurs during distillation. A further change is brought
about by bromine in aqueous or carbon bisulphide solution in sunlight (C. 1897,
II. 259). It can be separated from the solid crotonic acid by means of the
increased solubility of its sodium salt in alcohol, or its more easily soluble quinine
salt in water (C. 1897, II. 260 ; 1904,1.167). Melted with potassium hydroxide
isocrotonic acid yields only acetic acid, like the ordinary crotonic acid, into which
it may first be changed. Sodium amalgam has no action on it. It absorbs
HI, forming /Modobutyric acid (B. 22, R. 741). Chlorine unites with it to form
a liquid dichloridc, C4H6C12O2, the iso-a/3-dichlorobutyric acid, which gives
up HC1, changing into a-chlorocrotonic acid. KMnO4 oxidizes it to Isodihydroxy-
butyric acid (q.v.} (A. 268, 16).
(2a) a-Chloriso crotonic Acid is obtained by the action of sodium hydroxide
on free a/?-dichlorobutyric acid. It is the most soluble of the four chlorocrotonic
acids (B. 22, R. 52).
(26) When PC15 and water act on acetoacetic ester, CH3CO.CH2COC2H6,
jS-chlorisocrotonie acid (with /?-chlorocrotonic acid) is produced. It is very pro-
bable that j8-dichlorobutyric acid is formed at first, and this afterward parts with
HC1. It is also formed by protracted heating of jS-chlorocrotonic acid.
Sodium amalgam converts both the a- and jS-chlorisocrotonic acids into liquid
isocrotonic acid (B. 22, R. 52).
a-Bromisocrotonic Acid is produced by the action of sodium hydroxide on
free a/?-dibromobutyric acid (B. 21, R 242).
(3) Vinyl Acetic Acid, CH2:CH.CH2COOH, b.p.;, 71°, is produced, together
with glutaconic acid, by heating /J-hydroxyglutaric acid ; also from £-bromo-
n-glutaric acid by the action of sodium hydroxide solution ; or by heating a
solution of its neutral sodium salt. It can further be obtained from allyl
bromide, CO2, and Mg, in ether (B. 36, 2897). It is an oil, volatile in steam.
Boiling with sodium hydroxide converts it into ordinary crotonic acid and
jS-hydroxybutyric acid ; acids produce the ordinary crotonic acid only. Bromine
changes it into /ty-dibromobutyric acid, which gives ^3-hydroxy-y-butyrolactone
when boiled with water. Calcium salt, (C4H5O2)2Ca+H2O (B. 35, 938), Vinyl
Acetonitrile, Allyl Cyanide, CH2:CH.CH2CN, b.p. 118°, obtained from allyl
bromide or iodide with alkali cyanide, yields solid crotonic acid on hydrolysis,
accompanied by internal change. Bromine produces jSy-dibromobutyronitrile,
which, on saponification, yields jSy-dibromobutyric acid ; reduction of the latter
with zinc and alcohol gives rise to vinyl acetic acid (C. 1905, I. 434).
(4) Methaerylie Acid, CH2:C<^3H, m.p. 16°, b.p. 160-5°. Its ethyl ester
was first obtained by the action of PC13 on hydroxy-isobutyric ester,
(CH3)2.C(OH).CO2.C2H6. It can be prepared from o-bromisobutyric acid
by warming it with concentrated sodium hydroxide solution (A. 342, 159).
It is, however, best prepared by boiling citrabromopyrotartaric acid (from
citraconic acid and HBr) with water or a sodium carbonate solution :
C6HTBrO4=C4H6O2+CO2+HBr.
It crystallizes in prisms which are readily soluble in water ; it polymerizes
on keeping and in contact with HC1 to Poly methacrylic A c id (B. 30, 1227). Sodium
amalgam easily converts it into isobutyric acid. With HBr and HI it forms
a-brom- and a-iodo-isobutyric acid, whilst bromine produces aj8-dibromiso-
butyric acid, whereby the assumed constitution is substantiated (J. pr. Ch. [2]
25, 369). Fusion with potassium hydroxide decomposes it "into propionic and
formic acids. The nitrile, b.p. 90°, is produced from acetone cyanhydrin by
P2O5 (C. 1898, II. 662). Bromomethacrylic acid and Isobromomethacrylic acids,
BrCH:C(CH3)COOH, m.ps. 64° and 66°, are produced from citra- and meso-
dibromopyroracemic acid. They are separated from one another by means of
298 ORGANIC CHEMISTRY
petroleum ether. Heat changes the iso-acid into the normal form, which on
further heating is decomposed into HBr, COZ, and allene (p. 90) (A. 343, 163).
The characterization of the four crotonic acids can be effected through their
anilides, C8H6.CO.NHC8H5, which are obtained by treating the acids with
PC16, aniline, and sodium hydroxide (B. 38, 254) :
Crotonic Anilide, m.p. 118°; Vinyl Acetic Amhde, m.p. 58°; Isocrotomc
Anilide, m.p. 102°; Methacrylic Anilide, m.p. 87°.
Pentenie Acids, C4H7.CO2H.
Of the isomers of this formula, angelic or ajB-dimethyl acrylic acid is the most
important. It bears the same relation to tiglic acid that was observed with
crotonic and isocrotonic acids (p. 295).
2. Angelic Acid, CHI8>C=C<CH23H> m-P- 45°, b.p. 185°, exists free
along with valeric and acetic acids in the roots of Angelica archangelica,
and as butyl and amyl esters, together with tiglic amyl ester, in
Roman oil of cumin, the oil of Anthemis nobilis.
Angelic acid congeals, when well cooled, and may be thus separated from liquid
valeric acid by pressure. Angelic and tiglic acids can be separated by means
of the calcium salts, that of the first being very readily soluble in cold water
(B. 17, 2261 ; A. 283, 105).
When 10 grams of angelic acid are boiled for twenty hours with sodium
hydroxide (40 grams NaOH in 160 grams of water), two-thirds of it are converted
into tiglic acid. Heating with water at 120° will change over one-half of it to
tiglic acid (A. 283, 108). When pure angelic acid is heated to boiling for hours
it is completely changed to tiglic acid. The same occurs by the action of
concentrated sulphuric acid at 100°. It dissolves without difficulty in hot water,
and volatilizes readily in steam ; ethyl ester, b.p. 141°.
Tiglic Acid, a-Methyl Crotonic Acid, CI*|>C=C<£°*H, m.p. 64-5°, b.p. 198°,
present in Roman oil of cumin (see above), and in croton oil (from Croton
tiglium), is a mixture of glycerol esters of various fatty and oleic acids. It can
be prepared from methyl ethyl hydroxy-acetic acid, (C2H6)C(CH3)(OH).COOH, by
the abstraction of water. Together with angelic acid it is obtained from hydroxy-
pivalic acid, HO.CH2C.(CH3)2COOH, by an internal change accompanied by the
loss of water, according to mode of formation 5 (p. 291). Also from acetaldehyde
and propionic acid, by mode of formation 10 (p. 291).
Ethyl ester, b.p. 152°, is converted by bromine into two dibromides (A. 250,
240 ; 259, i ; 272, i ; 273, 127 ; 274, 99). For their constitution, compare
B. 24, R. 668. The three possible acids, C4H7CO2H, with normal structure are
also known (Fittig, A. 283, 47 ; B. 27, 2658). Propylidene Acetic Acid, afi-Pentenic
acid, CH3.CH2.CH:CH.CO2H, m.p. 10°, b.p. 201°, is formed, together with T
hydroxyvaleric acid, on boiling ethylidene propionic acid with sodium hydroxide ;
as well as from malonic acid, propionic aldehyde and acetic anhydride, together
with j8y-pentenic acid ; dibromide, m.p. 56°. Ethylidene Propionic Acid, ^-Pentenie
acid, CH3CH:CH.CH2CO2H, b.p. 194°, is best prepared by the distillation of
methyl paraconic acid (B. 37, 1997). It is also produced by the reduction of
vinyl acrylic acid (p. 305) by sodium amalgam (B. 35, 2320) ; dibromide, m.p. 65°.
a- Ethyl Acrylic Acid, CH2=C(C2H5)COOH, m.p. 45°, b.p. 180°, is obtained
from o-bromo-a-ethyl succinic acid. On warming with concentrated sulphuric acid
it is partially changed to tiglic acid, partially into CO and methyl ethyl ketone,
CH3.CO.C2H? (C. 1905, I. 591). Sulphuric acid produces similar decompositions
and changes in the homologous a-alkyl acrylic acids (C. 1905, II. 612).
^-Dimethyl Acrylic Acid, (CHS)2C:CH.CO2H, m.p. 70°, is obtained (i) from
j8-hydroxy-iso valeric acid by distillation; (2) from acetone and malonic acid by
means of acetic anhydride (B. 27, 1574) ; (3) from its ester, produced when
a-bromisoyaleric acid ester is heated with diethylaniline (A. 280, 252) ; (4) from
mesityl oxide by the breaking-down action of sodium hypochlorite :
NaCIO
(CH,)aC:COCH, > (CH,),C:CHCOOH+CHC1,.
OLEIC ACIDS, OLEFINE MONOCARBOXYLIC ACIDS 299
(C. 1905, II. 614.) The ethyl ester and HNO3 yield two isomeric mononitro
compounds. See B. 29, R. 956 for its derivatives.
Allyl Acetic Acid, yB-Pentenic Acid, CH2:CH.CH2.CH2.CO2H, b.p. 187°, is
obtained on heating allyl malonic acid.
Hexenic Acids, C,H10O2.
The normal acids belonging to this class are Hydro- and Isohydrosorbic Acids.
Hydrosorbie Acid, Propylidene Propionic Acid, py-Hcxenic Acid, CH3,CH2.-
CH:CH.CH2.CO2H, b.p. 208°, is obtained from ethyl paraconic acid, CH3.CHa.-
CH.CH(CO2H)CH2COO, according to method 13 (p. 292) ; hence it is probably
a j8y-unsaturated acid. It is the first reduction product of sorbic acid, CHSCH:CH.-
CH:CH.CO2H. During the reduction a shifting of the double union occurs. On
boiling hydrosorbic acid with sodium hydroxide, it passes into the Jsomer
whose formation one might expect in the reduction of sorbic acid — into Isohydro-
sorbic Acid, or Butylidene Acetic Acid, afi-Hexenic Acid, CH3CH2CH2CH:CHCO2H,
m.p. 33°, b.p. 216°. It is also prepared, together with a little of the jSy-acid, by
heating o-brotnocaproic ester with quinoline (B. 24, 83 ; 27, 1998). When its
bromine addition product is boiled with water, hydroxy-caprolactone and homo-
laevulinic acid result (A. 268, 69).
yb-Hexenic acid, CH3CH:CH.CH2CH2COOH, m.p. o°, b.p. 206° (see mode of
formation 13, p. 292). Permanganate breaks it down into acetic acid and succinic
acid (B. 37, 1999).' ^-Hexenic acid, CH2:CHCH2CH2CH2COOH, b.p. 203°, is
formed, together with the y8-acid, from a-hydroxy-a-methyl adipic acid by
the action of heat ; also from a-aminocaproic acid by means of nitrous acid
(B. 37, 1999).
Vinyl Dimethyl Acetic Acid, CH2:CH.C(CH3)2COOH, b.p. 185°. Its ester is
obtained from aajS-trimethyl hydracrylic ester by P2O6. The acid is oxidized
by permanganate to dimethyl malonic acid, (CH3)2C(COOH)2. Analogously
many homologous alkenyl dimethyl acetic acids can be obtained (C. 1906, II. 317,
1116). Their dibromides are partially decomposed by alkalis in an abnormal
manner.
afi-Isohexenic Acid, fi-Isopropyl Acrylic Acid, (CH3)2CH.CH:CHCOOH, b.p.
212°, from jS-hydroxycaproic acid or a-bromisocaproic ester (B. 29, R. 667 ;
C. 1899, I. H57).
Ethyl Crotonic Acid, CH3.CH:C(C2H5)COOH, m.p. 40°, and Ethyl Isocrotonic
Acid, b.p. 200°, are obtained together on the distillation of diethyl glycolic acid,
(C2H5)2C(OH).COOH. The first is a sublimable solid, the second a liquid. The
latter is converted into the solid acid when heated under pressure to 200° (A. 334,
105). The calcium salt of the iso-acid is less soluble in hot water than in cold.
Pyroterebie Acid, (CH3)2C:CH.CH2.CO2H, and Teracrylie Acid, C3H7.-
CH:CH.CH2.C02H, b.p. 218° (A. 208, 3?, 39), belong to the acids CeH^O, and
C7H12O2. They deserve notice because of their genetic connection with two
oxidation products of turpentine oil — terebic acid and terpenylic acid — which will
be considered in Vol. II. Pyroterebie acid is changed by protracted boiling or
by HBr to isomeric isocaprolactone :
(CH3)2C.CH2.CH2COO.
Teracrylie acid is converted by HBr into the isomeric heptolactone :
C,H7CH.CH2.CH2.COO.
Nonylenic Acid, CH3(CH2)5CH:CH.COaH, from oenanthol by general method
of formation 10, p. 291.
Decylenic Acid, C8H13.CH=CH.CHa.CO2H, is formed from hexyl paraconic
acid, according to general method of formation u, p. 292.
Undecylenic Acid, CH2=CH(CH2)8CO2H, m.p. 24-5°, b.p.,B 165°, is pro-
duced, together with cenanthol (p. 201) (C. 1901, I. 612) by distilling castor oil
under reduced pressure. It yields sebacic acid, (CH2)8(CO2H)2 (q.v.), on oxida-
tion (B. 19, R. 338 ; 19, 2224). Chloride, b.p.14 128° ; anhydride, m.p. 13°,
b.p.n 170° ; nitrile, b.p.14 130° (B. 33, 3580) ; amide, m.p. 85° (B. 31, 2349).
When its dibromide, m.p. 38°, is incompletely decomposed by alcoholic potassium
hydroxide, Dehydro-undecylenic Acid, CH^C[CH2],CO2H, m.p. 43°, is obtained,
which, fused at 180° with potassium hydroxide, changes to Undecolic Acid,
CH$.C:C[CHj]7C02H, m.p. 59° (B. 29, 2232).
300 ORGANIC CHEMISTRY
Higher Oleflne Monocarboxylic Acids.
To ascertain the point of the doubly linked carbon atoms in the higher olefine
monocarboxylic acids, the latter are converted into their corresponding acetylene
monocarboxylic acids (p. 302), which, in turn, are oxidized and split open at the
point of triple carbon union ; or they are changed to ketone carboxylic acids,
and these are then broken down. Thus, oleic acid yields stearolic acid, which
maybe oxidized to azelaic acid, C7Hi4(CO2H)2, and pelargonic acid, C,Hi7CO2H,
This would mean that in stearolic acid the carbon atoms 9 and 10 are united by
three bonds, and that they are the atoms which in oleic acid are in double union.
This conclusion is confirmed by the conversion of stearolic acid, by means of
concentrated sulphuric acid, into ketostearic acid, whose oxime undergoes the
Beckmann rearrangement at 400°, as the result of the action of concentrated
sulphuric acid. Two acid amides result, which are decomposed by fuming
hydrochloric acid, the one into octylamine and sebacic acid, the other into pelar-
gonic acid and 9-aminononanic acid (B. 27, 172) :
Oleic Acid. C8H17CH:CH[CH2]7C02H > CaH17CHBr.CHBr[CH2]7CO,H
i^^
Stearolic Acid. C.H17C=[CH2]7CO2H > C.H17CO.CH2[CH2]7CO2H
Ketostearic Acid.
Ketoxime- C.H17C(NOH)[CH J.CO.H
stearic Acid.
y \
C8H17NHCO[CH2]8C02H C8H17CO.NH[CH2]8CO2H
C8H17NH, [CH2]8(C02H), C8H17CO2H NH2[CH2]8CO2H
Octylamine. Sebacic Acid. Pelargonic Acid. 9-Aminononanic
Acid.
The constitution of hypogajic and erucic acids has been determined in the
same manner.
The constitution of stearolic acid still remained doubtful, however, since
ketostearic acid, C18H17CO[CH2]8COOH, could also be formed from an acid of
the formula C7H15C=C[CH2]8COOH. However, the assumed constitution of oleic
acid was substantiated by boiling its ozonide with water, whereby the decom-
position products, nonyl aldehyde and azelaic aldehyde acid, were obtained
together with their oxidation products, pelargonic acid and azelaic acid (B 39
3732):
C8H17CH-CH[CH,]7COOH > C,H17CHO+OCH[CH2]7COOH.
O,
Hypogaeic Acid, CH3[CH2]7CH:CH[CH2]6CO3H, m.p. 33', b.p.15 236°, found
as glycerol ester in earthnut oil (from the fruit of Arachis hypogaa), crystallizes in
needles. It results when stearolic acid is fused with KOH at 200° (B. 27, 3397).
Oleic Acid, C8HM>C:C<gH2]7C02H=C18H3402, m.p. 14°, b.p.10
223°, occurs as glycerol ester (triolein) in nearly all fats, especially
in the oils, as olive oil, almond oil, cod-liver oil, etc. It is obtained
in large quantities as a by-product in the manufacture of stearic
acid (p. 264).
», ^In PfeParinS oleic acid» olive or almond oil is saponified with potassium
Hydroxide and the aqueous solution of the potassium salts precipitated with lead
acetate, ihe lead salts which separate are dried and extracted with ether, when
lead oleate dissolves, leaving as insoluble the lead salts of all other fatty acids,
ihe ethereal solution is mixed with hydrochloric acid, the lead chloride is filtered
cm, and the liquid is concentrated. The acid obtained in this way may be frac-
tionated by distillation under strongly diminished pressure
OLEIC ACIDS, OLEFINE MONOCARBOXYLIC ACIDS 301
Oleic acid in a pure condition is odourless, and does not redden
litmus. On exposure to the air it oxidizes, becomes yellow, and
acquires a rancid odour. Nitric acid oxidizes it with formation of all
the lower fatty acids from capric to acetic, and at the same time dibasic
acids, like sebacic acid, are produced. A permanganate solution
oxidizes it to azelaic acid, C9H16O4. Moderated oxidation produces
dihydroxystearic acid, m.p. 136° (C. 1898, 1. 176, 629 ; 1899, I. 1068).
It unites with bromine to form liquid dibromostearic acid, C18H34Br2Oa, which
is converted by alcoholic KOH into monobromoleic acid, C19H33BrO2, and then into
stearolic acid (p. 304). Reduction by hydrogen and finely divided nickel
(C. 1903, I. 1199), or by electrolytic methods (C. 1905, II. 305) converts oleic
acid into stearic acid.
Oleic Anhydride, m.p. 28° (C. 1899, I. 1070) ; chloride, b.p.lt 213° (B. 33,
3534).
ElaYdic Acid, c»H»>c>c<grH«l'co«H, m p ^ b p ^ ^^ results
from the action of nitrous acid on oleic acid. Oxidation with KMnO4
produces a dihydroxystearic acid, m.p. 99° (C. 1899, I. 1068). Elaidic
Bromide, m.p. 27°, is reconverted into the acid by sodium amalgam ;
chloride, b.p.13 216° ; anhydride, m.p. 50° ; nitrite, b.p.16 214° (B. 33,
3582) ; amide, m.p. 90° (C. 1899, I. 1070).
Iso-oleic Acid, CltHstOt, m.p. 44-45°, is obtained from the Hi-addition pro-
duct of oleic acid — iodostearic acid — by treatment with alcoholic potassium
hydroxide ; or from hydroxystearic acid, formed from oleic acid by the action
of concentrated sulphuric acid, by distillation under reduced pressure (B. 21,
R. 398 ; 21, 1878 ; 27, R. 576).
Hydriodic acid reduces oleic and elaidic acids to stearic acid. Oleic, elaidic,
and iso-oleic acids, when fused with potassium hydroxide, break down into
palmitic acid and acetic acid. This is, however, a reaction that cannot be accepted
as proving that the double union in the three acids holds the same position.
The common view is that oleic and elaidic acids are stereoisomers, and that
iso-oleic is a structural isomer of the other two acids.
Bromine converts the three acids into three different dibromostearic acids.
Carefully oxidized with potassium permanganate, they yield three different
dihydroxy-stearic acids.
A?-Oleic Acid, CH3[CH8]14CH.CHCOOH, m.p. 59, is prepared from a-iodo-
stearic acid and alcoholic potassium hydroxide. Potassium permanganate pro-
duces 2, ^-Dihydroxystearic Acid, m.p. 120°, and subsequently palmitic acid (C.
1906, 1.819).
C* T-T TT
Erucic Acid, 8 y>C=C<{? H COOH' m*p§ 33~34°» b-P-io 254'5°. occurs
as its glyceride in rape-seed oil (Brassica campestris), in the fatty oil of mustard
seed, and in grape-seed oil. By oxidation, erucic acid yields nonylic acid
and brassylic acid (B. 24, 4120 ; 25, 961, 2667 ; 26, 639, 838, 1867, R. 795, 811);
anhydride, m.p. 47-50° (C. 1899, I. 1070).
Isoerucic Acid, see B. 27, R. 166, 577.
Brassidic Acid, c HH>C=C<|? H CQOH' m'p* 66°' b-P'1» 256°' is PrePared
from erucic acid by the action of nitrous acid (B. 19, 3320) and is to erucic acid
what elaidic acid is to oleic.
Linoleic and ricinoleic acids, although not belonging to the same
series, yet closely resemble oleic acid. The first is a simple, unsatu-
rated acid, the second an unsaturated hydroxy-acid.
Linoleic Acid, Linolic Acid, C18H32O2, occurs as its glyceride in
'ing oils, which quickly oxidize in the air, become covered with
dryi
302 ORGANIC CHEMISTRY
a skin, and then solidify — e.g. linseed oil, hemp oil, poppy oil, and
nut oil. In the non-drying oils — olive oil, rape oil from Brassica
campestris, rape oil from Brassica rapa, almond oil, fish oil, etc. —
the oleic glycerol ester occurs.
Various hydroxy-fatty acids are produced when linoleic acid is oxidized with
potassium permanganate. From the fact that they can be formed, it has been
concluded that certain other acids exist in the crude linoleic acid (B. 21, R. 436
and 659). On Oleomargoric Acid, as a stereoisomer of linolic acid, obtained
from Japanese wood oil, see, C. 1903, II. 657.
Ricinoleic Acid, C18H34O3 = CH3[CH2]5.CHOH.CH2CH:CH(CH2)7-
C02H,|>]D=-f 6-67° (B. 27, 3471), is present in castor oil in the form
of a glyceride, [a]D= +3°. The lead salt is soluble in ether. Subjected
to dry distillation, ricinoleic acid splits into cenanthol, C7H14O, and
undecylenic acid, CnH20O2.
Fused with potassium hydroxide, it changes to sebacic acid, C8H16(CO2H)2,
and sec.-octyl alcohol, (C8H13)CHOH.CH3. It combines with bromine to form
a solid dibromide. When heated with HI (iodine and phosphorus), it is trans-
formed into iodoleic acid, C)8H33IO2, which yields stearic acid when heated with
zinc and hydrochloric acid (B. 29, 806).
The point of double union between the carbon atoms in ricinoleic acid is
ascertained as in the case of oleic acid :
(i) By conversion into ricinostearolic acid, m.p. 53°, (2) and this into keto-
hydroxy stearic acid, m.p. 84°, (3) finally, by the breaking down of the oxime
of the latter acid (B. 27, 3121 ; C. 1900, II. 37).
Nitrous acid converts ricinoleic acid into isomeric ricinelaidic acid, m.p.
53° C. (see B. 21, 2735 ; 27, R. 629).
Alkyl ester and Acyl derivatives (B. 36, 781).
Rapinic Acid, C18H34O2, occurs as glycerol ester in rape oil (B. 29, R. 673).
TJnsaturated Acids, CnH2n-3C02H.
The acids of this series contain either a trebly linked pair of carbon
atoms, e.g. like acetylene (p. 86), or two doubly linked pairs of carbon
atoms, as in the diolefines. They are, therefore, distinguished as acety-
lene monocarboxylic acids : propiolic acid series and diolefine mono-
carboxylic acids.
C. ACETYLENE CARBOXYLIC ACIDS
Methods of Formation. — (la) By the action of alcoholic potassium
hydroxide on the brom-addition products of the oleic acids, and (b)
the monohalogen substitution products of the oleic acids. This is
similar to the formation of the acetylenes from the di-halogen sub-
stitution products of the paraffins and the mono-halogen substitution
products of the defines.
(2) From the sodium derivatives of the mono-alkyl acetylenes by
the action of C02 :
CH3.C=ECNa+CO2 = CH3C==C.CO2Na.
Like the acetylenes, they are capable of taking up 2 and 4 monovalent
atoms.
ACETYLENE CARBOXYLIC ACIDS 303
The addition of the constituents of water at the treble bond converts these
substances into keto-acids. Like the /3-keto-acids (q.v.) the a/?-acetylene car-
boxy lie acids (alkyl propiolic acids) lose COa on heating and become converted into
acetylenes. Boiling with aqueous alkalis produces intermediate /?-keto-acids,
which break up into ketones and alkali carbonates (comp. C. 1903, II. 487,
etc.).
Ammonia converts alkyl propiolic esters into amides, which give up water
to phosphoric anhydride, forming nitriles. Primary and secondary amines
when added on to the molecule form (3-amino-acrylic acids ; hydrazines form
pyrazolons. A solution of sodium alcoholate or alcoholic potassium hydroxide,
acting on esters or nitriles, produce derivatives of fi-alkoxyacrylic acids or B-acetal
carboxylic acid, RC(OC2H5):CHCOOH and RC(OCaH3)a.CHaCOOH (C. 1904,
I. 659 ; 1906, I. 651, 912, 1095 ; 1907, I. 25, 738).
Propiolic Acid, Propargylic Acid [Propine-Acid], CH:C.CO2H, m.p. 6°, b.p.
144°, with decomposition, corresponds with propargyl alcohol (p. 125). The
potassium salt, C3HO2K-fH2O, is produced from the primary potassium salt of
acetylene dicarboxylic acid, when its aqueous solution is heated :
C.C02H CH
III
C.C02K
III +co,
C.COaK
similarly to the production of acetic acid from malonic acid (p. 256).
The aqueous solution of the salt is precipitated by ammoniacal silver and
cuprous chloride solutions, with formation of explosive metallic derivatives. By
prolonged boiling with water the potassium salt is decomposed into acetylene
and potassium carbonate.
Free propiolic acid, liberated from the potassium salt, is a liquid with an
odour resembling that of glacial acetic acid. It dissolves readily in water,
alcohol, and ether, and reduces silver and platinum salts. Exposed to sunlight
out of contact with the air it polymerizes to trimesic acid:
3C2H.C02H =C6H3(C02H)8.
Sodium amalgam converts it into propionic acid. It forms j8-halogen acrylic
acids with the halogen acids (p. 294) (B. 19, 543), and with the halogens yields
a/J-dihalogen-acrylic acids.
Ethyl Ester, b.p. 119°. With ammoniacal cuprous chloride it unites to a
stable yellow-coloured compound. Zinc and sulphuric acid reduce it to ethyl
propargylic ester (p. 129) (B. 18, 2271).
Chloropropiolic Acid, CC1^C.CO2H, is produced from dichloracrylic acid
(p. 295), and Bromopropiolic Acid, C3BrHO2, from mucobromic acid. lodo-
•propiolic Acid, m.p. 140°, is obtained by saponifying its ethyl ester, m.p. 68°,
which may be prepared from the Cu compound of propiolic ester by the action
of iodine.
The three acids decompose readily into carbon dioxide and spon-
taneously inflammable chlor acetylene, CC1=CH, bromacetylene and
lodoacetylene. The addition of halogen acids leads to j3/J-di-
halogen acrylic acids, whilst the halogens give rise to trihalogen
acrylic acids.
Carbon dioxide converts the sodium compounds of the corre-
sponding alkyl acetylenes into the following homologues of propiolic
acid (B. 12, 853; J. pr. Ch. [2] 87,417; B. 33, 3586): the same
result is obtained with chlorocarbonic esters (C. 1901, I. 1148 ;
3, I. 824 ; II. 487) :
RC=CNa+ClCO2C2H$ -— ->- RC=CCO2CaH5-r.NaCl.
3o4 ORGANIC CHEMISTRY
Tetrollc Acid, Methyl Acetylene Car- M P. B. P
boxylicAcid , CH3C=C.C02H 76° 203°
Ethyl Acetylene Carboxylic Acid . . . CH3.CH2.C=c.COaH 80°
n-Propyl Acetylene Carboxylic Acid . CH3.CH2.CHa.CEEC.COaH 27° 125°
(20 mm.)
Isopropyl Acetylene Carboxylic Acid . . (CH3)2CH.C=EC.CO2H 38° 107°
(20 mm.)
n-Butyl Acetylene Carboxylic Acid . . CI 1 3.[CH2]3CEEC.CO2H liquid 136°
(20 mm.)
tert. Butyl Acetylene Carboxylic Acid . . (CH3)3C.C=C.COaH 48° no0
(10 mm.)
Amyl Propiolic Acid C5HUC^C.CO2H 5° 149°
(20 mm.)
Hexyl Propiolic Acid C6H13C=C.CO2H -10° 155°
(18 mm.)
Heptyl Propiolie Acid C7H15C=EC.CO2H 6-10° 166°
(20 mm.)
Nonyl Propiolic Acid C9H18C=C.CO2H 30°
Tetradecyl Propiolic Acid CH3[CH2]13OEEC.CO2H 44°
Of these, Tetrolic Acid has been the most thoroughly investigated, and is
obtained from j3-chlorocrotonic acid and /3-chlorisocrotonic acid when these are
boiled with potassium hydroxide (A. 345, 103). At 210° the acid decomposes
into CO a and allylene, C,H4 (B. 27, R. 751). Potassium permanganate oxidizes
it to acetic and oxalic acids. It combines with HC1 and HBr, forming jS-chloro-
crotonic acid and /?-bromocrotonic acid (B. 22, R. 51 ; 21, R. 243). With bromine,
in sunlight, it yields dibromocrotonic acid, m.p. 120°, whereas in the dark the
halogen produces the isomeric dibromocrotonic acid, m.p. 94° (B. 28, 1877 ; 34,
4216). aaj8-Trichlorobutyric acid (p. 289), upon the loss of HC1, yields two
dichlorocrotonic acids, m.p. 75° and 92° (B. 28, 2665). These two acids are also
produced when chlorine acts on tetrolic acid.
Tetrolic Ethyl Ester, b.p. 164°, forms the amide, m.p. 148°, with ammonia,
together with )5-aminocrotonic ester. An aqueous solution of the amide, when
heated with mercuric chloride, becomes hydrated, forming acetoacetic amide :
CH3C==CCONH2 > CH8CO.CHaCONH,,
Phenylhydrazine forms the tetrolic ester, phenyl methyl pyrazolone ; diazoacetic
ester produces a pyrazole derivative (A. 345, 100).
Several higher homologues of propiolic acid have been prepared by the action
of alcoholic potassium hydroxide on the brom-addition products of the higher
define monocarboxylic acids (p. 300).
Undecolic Acid, CH,C:C[CH2]7CO2H, m.p. 59°, is obtained from undeclyenic
acid (p. 299). By oxidation, azelaic acid is formed (B. 33, 3571). Isomeric with
it is dehydro-undecylenic acid (p. 299). Stearolic Acid, C8H17CiC[CH2]7CO2H,
m.p. 48° (constitution, see p. 300), is obtained from oleic and ela'idic acids.
Behenolic Acid, C22H40O2, m.p. 57'5° (constitution, see p. 300), from the
bromides of erucic and brassidic acids (B. 24, 4116 ; 26, 640, 1867). On warm-
ing the last two acids with fuming nitric acid they yield the monobasic acids :
stearoxylic, or g,io-diketostearic acid, CH3[CH2]7CO.CO[CH2]7CO2H, m.p. 86°,
and behenoxylic, or i^,i^-dikeiobehenic acid, CH3[CH2]7CO.CO.[CH,]11CO2H, m.p.
96° (B. 28, 276).
Sulphuric acid converts stearolic acid into ketostearid acid, and behenolic
acid into ketobrassidic acid (B. 26, 1867), whose oximes are then converted by
the sulphuric acid into C8H17CO.NH[CHa]8CO,H (p. 300). (Oxidation, confp.
Erucic and Brassidic Acids, p. 301.)
DIOLEFINE CARBOXYLIC ACIDS 305
D. DIOLEFINE CARBOXYLIC ACIDS
AV-Diolefine carboxylic acids are obtained by the two following general
methods : —
(1 ) By the condensation of aj8-olefine aldehydes with malonic acid, by means
of pyridine (B. 35, 1143).
C6H5N
CH2:CH.CHO+CH2(COOH)a > CHa:CH.CH:CHCOOH+HaO+COa.
(2) By the condensation of olefine aldehydes or ketones by means of halogen
fatty acid esters and zinc, and subsequently splitting off water from the jS-hydroxy-
olefine carboxylic esters thus formed, by heating with alkalis (B. 35, 3633 ;
36, 15, C. 1903, II. 555) :
CH8CH:CH.CHO-fBrZnCHaCOaR > CH3CH:CH.CH(OH)CH3COOR
> CH3CH:CH.CH:CH.COOH.
Some of these acids are polymerized by barium hydroxide to di- and tri-
molecular modifications which give up CO2, forming the corresponding cyclic or
trimolecular hydrocarbons (B. 35, 2129) containing an eight-membered ring ;
e.g. from j3- vinyl acrylic acid :
CH4.CH:CH.CH,
I =Cyclo-octadiene
CHa.CH:CH.CH,
CHj.CHiCH.CH,
CH .CHiCH.CH =Dicyclo-dodecatricne
AT
CH2.CH:
CH.CHj.
Butadiene Carboxylic Acid, CH2:CH.CH:CHCO2H, m.p. 102°, is formed,
together with ethylidene propionic acid (p. 298), by the reduction of Perchloro-
butadiene Carboxylic Acid,CClz:CCl.CCl:CCLCO2H, m.p. 97°, and Perchlorobutine
Carboxylic Acid, CC13.C:C.CC12.CO2H, m.p. 127°. These are products of decom-
position resulting from the two hexachloro-R-pentenes (Vol. II.) on treatment
with alkali (B. 28, 1644).
product with water. Reduction by sodium amalgam brings
at the 1,4 bonds (p. 90), forming a/?y-pentenic acid (p. 298). Oxidation with
permanganate converts it into racemic acid (B. 35, 1136). It is isomeric with
butadiene carboxylic acid, towards which it may stand in the same relation as
fumaric acid to maleic acid (private information from Herr Doebner).
Sorbic Acid, CHSCH=CH.CH=CH.COOH, m.p. 134-5°, b.p.228°,is obtained,
together with malic acid, from the oil in the unripe juice of the berries of mountain
ash (Sorbus aucuparia) (1859, A. W. Hofmann, A. 110, 129). It exists there in
the form of a lactone, the so-called parasorbic acid (q.v.), which is boiled with
sodium hydroxide or hydrochloric acid (B. 27, 351). Synthetically, it is prepared
from croton aldehyde and malonic acid with pyridine (Doebner, B. 33, 2140),
also from j3-hydroxy-y8-hexenic acid, by boiling it with a 20 per cent, barium
hydroxide solution (B. 35, 3636). Oxidation by KMnO4 produces aldehyde
and racemic acid (q.v.}, a reaction which reveals the structure of sorbic acid
(B. 23, 2377; 24,85):
CH8CH=CH.CH=CH.COOH+HaO+40=CH3CHO+COOH(CHOH)2COOH.
Sorbic Acid. Racemic Acid.
Sodium amalgam converts it into Hydrosorbic acid (p. 299). Heated with
ammonia, sorbic ac^ yields a diaminocaproic acid ; hydroxylamine brings about
a peculiar reaction resulting in acetyl acetone dioxime (p. 355) (B. 37, 3316).
Sorbic Ethyl Ester, b.p. 95°, a-Methyl Sorbic Acid, m.p. 91°, a-Ethyl Sorbic Acid,
b.p. 76°, and fib-Dimethyl Sorbic Acid, m.p. 93°, are obtained by method 2 (above).
VOL. I. X
3o6 ORGANIC CHEMISTRY
yc- Dimethyl SorbicAcid, b.p.M 165°. is prepared according to method i (p. 305)
from a methyl fl-ethyl acrolein and malomc acid.
Diallvl Acetic Acid, (CH2:CH.CHa)aCH.COaH, b.p. 227 , is obtained from
ethyl-diallvl acetoacetate and diallyj [ malonic acid. Nitric acid oxidizes it to
tricarballvlic acid (CO«H.CHj)jv^-HC/vJjri.
Geranlc Acid belongs to the class of olefine dicarboxyhc acids. It will be
described together with the olefine terpene bodies (Vol. II.).
IV. DIHYDRIC ALCOHOLS OR GLYCOLS, AKD
THEIR OXIDATION PRODUCTS
The monohydric alcohols, with their oxidation products,— the alde-
hydes, the ketones, and the monocarboxylic acids, with their deriva-
tives,—were discussed in the preceding section.
Closely allied to these are the dihydric alcohols or glycols, and
such compounds as may be considered oxidation products of the
glycols.
The glycols are derived from the hydrocarbons by the replacement
of two hydrogen atoms attached to two different carbon atoms by two
hydroxyls. In the case of the monohydric alcohols we distinguished
three classes — primary, secondary, and tertiary alcohols. With the
glycols the classes are twice as numerous. The compounds, which may
be considered as oxidation products of the glycols, contain either two
similar, reactive, atomic groups — e.g. :
the dialdehydes (glyoxal, CHO.CHO),
the diketones (diacetyl, CH3CO.COCH3),
the dicarboxylic acids (oxalic acid, COOH.COOH),
and therefore exhibit double the typical properties of the oxidation
products of the monohydric alcohols — compounds of double function /
or they contain two different reactive atomic groups in the same
molecule, and have, therefore, the typical properties of different
families of compounds. The following bodies have such a mixed
function :
Aldehyde Alcohols (Glycolyl Aldehyde, CH2OH.CHO).
Ketone Alcohols (Acetyl Carbinol, CH2OH.COCH3).
Aldehyde Ketones (Pyroracemic Aldehyde, CH3.CO.CHO).
Alcohol Acids or Hydroxyacids (Glycollic Acid, CH2.OH.COOH).
Aldehydic Acids (Glyoxvlic Acid, CHO.CO2H).
Ketonic Acids (Pyroracemic Acid, CH3.CO.COOH).
Four classes — alcohols, aldehydes, ketones, and monocarboxylic acids — occur
with the monohydric alcohols and their oxidation products, whilst in the case of
the dihydric alcohols and their oxidation products ten classes of derivatives are
known. The successive series in which these ten classes will be discussed readily
follow, if their systematic interdependence be developed similarly to that of the
univalent alcohols and their oxidation products.
MONOHYDRIC ALCOHOLS AND THEIR OXIDATION PRODUCTS.
I a. Primary Alcohols. 2. Aldehydes. 4. Monocarboxylic Acids,
ib. Secondary Alcohols. 3. Ketones.
lv. Tertiary Alcohols.
DIHYDRIC ALCOHOLS OR GLYCOLS
DIHYDRIC ALCOHOLS AND THEIR OXIDATION PRODUCTS.
307
la. Diprimary Glycols. 20. prim. Hydroxy- ya. prim. Hydroxycarboxylic
CH2.OH
CH2.OH
Glycol.
aldehydes.
4. Dialdehydes.
CHO
CH2OH
Glycolyl Aldehyde.
CHO
CHO
Glyoxal.
2b. sec. Hydroxyalde-
hydes.
3a. prim. Hydroxyke-,
tones.
5. Aldehydketones.
•2C. tert. Hydroxyalde-
hydes.
3&. sec. Hydroxyketones.
6. Diketones.
$c. tert. Hydroxyketones.
Acids.
8. Aldehydocarboxylic
Acids.
10. Dicarboxylic Acids.
COOH
CHj.OH
Glycollic Acid.
CO,H COOH
CHO COOH
Glyoxylic Acid. Oxalic Acid.
76. sec. Hydroxycarboxylic
Acids.
9. Ketone Carboxylic
Acids.
'jc. tert. Hydroxycarboxy-
lic Acids.
i b. Prim. sec. Glycols.
ic. Prim. tert. Glycols.
i d. Disec. Glycols.
le. Sec. tert. Glycols.
i/. Ditert. Glycols.
The dihydric alcohols and their oxidation products will be described
and discussed in the following order :
1. Glycols, Dihydric Alcohols.
2. Hydroxy aldehydes, Aldehyde Alcohols.
3. Hydroxyketones, Ketone Alcohols.
4. Dialdehydes.
5. Aldehyde Ketones.
6. Diketones.
7. Hydroxy acids, Alcohol Monocarboxylic Acids.
S. Aldehyde Monocarboxylic Acids.
9. Kefo-monocarboxylic Acids.
10. Dicarboxylic Acids.
From the very nature of the conditions there are no compounds in
any of these series which contain but one carbon atom in the mole-
cule. However, carbonic acid with its exceedingly numerous derivatives
will be introduced before the dicarboxylic acids — the carbonic acid group.
Carbonic acid is the simplest dibasic acid ; it is similar, in many respects, to
the dicarboxylic acids and a special type for such acids, which, like it, only occur
in an anhydride form. Formic acid, the simplest acid, showing, at one and the
same time, the character of an aldehyde and a monocarboxylic acid, might, for
the very same reason, have been placed before glyoxylic acid, at the head of the
aldehyde acids. However, it is customary to place formic acid at the head of
the fatty acids, because the acid nature in it appears more prominently than does
its aldehyde character.
.
I. DIHYDRIC ALCOHOLS OR GLYCOLS
A. PARAFFIN GLYCOLS
Wurtz (1856) discovered glycol, and thus succeeded in filling the
ap between the monohydric alcohols and the triacid alcohol, glycerol.
chose the name glycol to indicate the relation of the new body to
3o8 ORGANIC CHEMISTRY
alcohol on the one hand and glycerol on the other. Glycols are dis-
tinguished as a-, 0-, y-, S-, etc., according as the hydroxyls are attached
to adjacent carbon atoms (1,2), or in 1,3-, 1,4-, and 1,5- positions
respectively. There are also diprimary, primary-secondary, etc.,
glycols (consult p. 307). The Geneva names are obtained for the
glycols by attaching the final syllable " diol " to the name of the
parent hydrocarbon.
Glycols differ from the monohydric alcohols just as the hydroxides
of bivalent metals differ from those of univalent metals, or as a dibasic
acid from a monobasic acid. As a rule, the reactions leading from the
monohydric alcohols and glycols to their corresponding derivatives
are very similar. It is only in the case of the two hydroxyl groups
of the glycols that they are able to pass successively to completion,
and in so doing they give* rise first to substances which still show
the character of a monohydric alcohol. Take ethylene glycol, for
example : it is capable of forming a mono- and dialkali glycollate,
corresponding with the alcoholates of the monohydric alcohols, mono-
and dialkyl ethers, mono- and dihalogen esters, nitric acid esters and
esters of organic acids, e.g. :
CH..OH CH,.ONa CHa.ONa CH2.O.C2H8 CHa.O.CaHs
I I I I !
CH2.OH CH2.OH CH2.ONa CH2.OH CH2.O.C2HS
Glycol. Monosodium D,isodium Glycol Mono-ethyl Glycol Diethyl
Glycollate. Glycollate. Ether. Ether.
CH2.C1 CH2C1 CHj.O.COCH, CHa.O.COCH,
CH2.OH CH2C1 CH2.OH CH2.O.COCHt
Glycol Ethylene Glycol Monacetate. Glycol Diacetate.
Chlorhydrin. Chloride.
All the mono compounds also exhibit the character of monohydric
alcohols ; they and the di- compounds, which have been mentioned,
can be obtained from the glycols by the same methods as the corre-
sponding transposition products of the monohydric alcohols.
The sulphur- and nitrogen-containing derivatives of the glycols
correspond with like derivatives of the monohydric alcohols :
CHa.SH CHa.SH CHa.NHa CHa.NH,
CH2.OH CHa.SH CH2.OH CHa.NH,
Monothio-glycol.' Dithio-glycol. Hydroxyethylamine. Ethylene Diaraine-
The aldehydes have been repeatedly spoken of as the anhydrides of
dihydric alcohols, in which the two hydroxyl groups are joined to the
same carbon atom, and which can only exist under special conditions.
Yet, the ethers or acetals, esters and other derivatives of these hypo-
thetical compounds are stable. These bodies are naturally isomeric
with the corresponding derivatives of the dihydric alcohols, in which
the hydroxyls are attached to different carbon atoms. The following,
for example, are isomeric : —
CH8.CH<g;g*g« Acetal and 9H*-aC*H» Glycol Diethyl Ether
2 6 CH-O^CH
C\ C^C\C*~U f^T-T (~*\ f*f)r^TT
CH 3. CH "\OCOCH 3 Ethylidene Diacetate and • 2' 3 Glycol Diacetate
' CH.O.COCri
Aldehyde Ammonia and • 2 Hydroxyethylamine.
DIHYDRIC ALCOHOLS OR GLYCOLS 309
The cyclic derivatives of the glycols are extremely characteristic.
Thus, glycol yields two cyclic ethers :
CH2V CH2.O.CH2
>O Ethylene Oxide. Diethylene Oxide,
CH/ CH2.O.CH2
and also sulphur- and nitrogen-compounds corresponding with diethy-
lene oxide :
CH2V CH2.NH.CH, CH2.S.CH, CH2.NH.CHa
1 VH || || |i
CH/ CH2.NH.CH2 CH2.S.CHa CH2.O.CH2
Ethylene Imide. Diethylene Imide. Diethylene Disulphide. Diethylene Imide Oxide.
Methods of Formation. — The first three methods are concerned with
the olefines, and lead, according to the constitution of the latter, to
glycols of every description.
The halogen addition products of the olefines — the alkylene halides
— may be regarded as the halogen acid esters of the glycols. When these
are acted on by alkalis, with the purpose of exchanging hydroxyl
for their halogen, by loss of halogen acid, they pass first into
monohalogen olefines and then into acetylenes. It was Wiirtz who
observed that it was only necessary to treat the alkylene halides with
acetates in order to reach the acetic esters of the glycols, and then,
by saponification with alkalis, to obtain the glycols.
(i) By heating the alkylene halides (p. 94) with silver acetate and
glacial acetic acid, or with potassium acetate in alcoholic solution :
CH2I CH3COOAg CH2OCOCH3
CH2I+CH3COOAg = CH2OCOCH3
Ethylene Diacetate.
Inasmuch as the alkylenes are prepared from monohydric alcohols
by withdrawal of water, and are transformed by the addition of
halogens into alkylene halides, the preceding reaction may be regarded
as a method of converting monohydric alcohols into dihydric alcohols
or glycols. The resulting acetic esters are purified by distillation, and
then saponified by KOH or barium hydroxide solution (C. 1899, 1. 968) :
CHaOCOCH3 KOH CHaOH
+ = | +2CH3COOK.
CHaOCOCH3 KOH CH2OH
A direct conversion of alkylene halides into glycols may be attained by heating
them with water (A. 186, 293 ), with water and lead oxide, or sodium and potassium
carbonates.
(2) Another procedure consists in shaking the alkylenes, CnH2n, with aqueous
hypochlorous acid, and afterwards decomposing the chlorhydrins fdrmed with
moist silver oxide :
CHj OH CH2OH AgOH CHjOH
CH, Cl ~CH2C1 CH2OH
(3) By the oxidation of the olefines (a) in alkaline solution (p. 84) (Wagner, B.
21, 1230) with potassium permanganate, or (b) with hydrogen peroxide. Thus,
ethylene yields ethylene glycol; isobutylene, isobutylene glycol, (CH8)a.C(OH').«
CHa.OH :
CHa CH2.OH
|| +0+H.O = |
CHg CHa.OH
3IO ORGANIC CHEMISTRY
(4) By the action of nitrous acid on diamines (p. 163). As they
can be obtained from the corresponding nitriles of dibasic acids, and
the nitriles themselves from alkylene halides, these reactions not
only ally the classes of derivatives mentioned, but they afford a means
of building up the glycols :
CH2Br CHaCN CHaCHaNHa CH2CH2OH
CH2 ^CH2 ^CH2 ^CH2
CH2Br CH2CN CH2CH2NH2 CH2CH2OH
Trimethylene Trimethylene Pentamethylene Pentamethylene
Bromide. Cyanide. Diamine. Glycol.
Besides the normal glycols, isomeric glycols are sometimes obtained,
as well as olefine alcohols and diolefines (B. 40, 2589).
(50) By reduction of aldehydes or keto-alcohols, dialdehydes or
dike tones.
By this means the a-keto-alcohols butyroin and caproin (p. 342)
yield the stereoisomeric forms of 4,5-octane-diol and 6,7-decanedo-
diol ; aldol (p. 338) gives ay-butylene glycol ; y-acetobutyl alcohol
(p. 342) gives i,5-hexane-diol, and acetonyl acetone (p. 351) yields
2,5-hexane-diol.
Akin to these reactions is the formation of glycol by the conden-
sation of isobutyl alcohol, alone or when mixed with other aldehydes,
by means of alcoholic potassium hydroxide. An aldol (p. 338) is first
formed, of which the aldehydic group is acted on by excess of butyl
aldehyde producing a monobutyrin of the i,3-glycol (comp. p. 194),
which in turn is decomposed by hydrolysis into the glycol and iso-
butyric acid (M. 17, 68 ; 19, 16) :
3(CH3)aCH.CHO > (CH3)2CH.CH(OH) CH(CH3)2 (CH3)aCH.CHOH
(CH3)aC.CH2O CO (CH8)2C.CHaOH
CH(CH3)2
COOH.
(5&) By the reduction of dicarboxylic esters or amides by sodium
and alcohol (C. 1905, II. 1701).
(CH3)2C.CO2R (CH3)2C.CH2OH
CH2.COaR CH2CH2OH
unsym.-Dimethyl ^-Dimethyl Tetramethylene
Succinic Ester. Glycol.
CHa.CHa.CH2.CONH2 CH2.CHa.CHaCH2OH
CHa.CHa.CH2.CONHa CH2.CH2.CH2CH2OH.
Suberic Amide^ Octomethylene Glycol.
Lactones, the cyclic esters of y-, 8-, or €-hydroxy-carboxylic esters,
are also reduced to glycols by sodium and alcohol (B. 39, 2851);
similarly, j8-ethoxyl propionic ester yields the ethyl ether of trimethyl-
ene glycol (C. 1905, I. 25).
Nucleus Synthetic Methods
(6a) Aldehyde alcohols, diketones, keto-carboxylic esters, dicar-
boxylic esters, all react with alkyl magnesium halides (p. 185) forming
:H2COOC2H6 CH2C(CH8)2OH
lethyl Tetramethylene Glycol.
DtHYDRIC ALCOHOLS OR GLYCOLS 311
glycols, accompanied by the entry of an alkyl group (B. 35, 2138 ;
C. 1904, I. 578 ; 1906, II. 1639 ; I907> L 627) :
CH,CH(OH) CH,Mgl CH8.CH(OH)
CHjCHO CH2CH(OH)CH8
Aldol. Dimethyl Trimethylene Glycol.
CH2COOCaH6 4CH3Mgl CH2C(CH3)2OH
C
Succinic Ester. Tetramethyl
By the same reagent alkoxy-ketones and alkoxy-carboxylic esters
are converted into monoalkyl ethers of the glycols (C. 1904, I. 504).
Similarly, lactones yield primary-tertiary glycols (C. 1907, I. 708).
(6b) The action of metals, such as sodium or magnesium, on many
halogen-hydrin compounds of the ethers, either alone or mixed with
halogen methyl alkyl ethers (p. 206), is to build up the ethers of the
higher glycols from lower members (C. 1903, I. 455 ; 1904, 1. 1401) :
Na
2C8H5O.CH2CH,CH,I - > C6H60[CH2]SOC6H6 - > HO[CH2]6OH
y-Phenoxypropyl Iodide. Hexamethylene Glycol.
HO[CH2]4OH
rameth
Glycol.
The monoalkyl ethers of the glycols can be obtained by the similar
reaction of chloromethyl alkyl ether on ketones in the presence of
magnesium or other metals (C. 1907, I. 681).
(7) Ditertiary glycols result, together with secondary alcohols, in
the reduction of ketones (p. 230). In this manner pinacone or tetra-
methyl ethylene glycol (p. 313) was made from acetone (Ffiedel) :
Amyloxypropyl Tetramethylene
Bromide.
(8) A few glycols have been obtained in the form of their dialkyl
ethers by the electrolysis of alkoxy-carboxylic acids. This is similar
to the production of ethane from potassium acetate (p. 73, and C.
1905, I. 1698).
Properties. — The glycols are neutral, thick liquids, holding, as far
as their properties are concerned, a place intermediate between the
monohydric alcohols and trihydric glycerol. The solubility of a
compound in water increases according to the accumulation of OH
groups in it, and becomes correspondingly less soluble in alcohol,
and especially in ether. There will be also an appreciable rise^in the
boiling point, whilst the body acquires at the same time a sweet
taste, inasmuch as there occurs a gradual transition from the hydro-
carbons to the sugars. In accord with this, the glycols have a sweetish
taste, are very easily soluble in water, slightly soluble in ether, and
boil much higher (about 100°) than the corresponding monohydric
alcohols. As the number and dimensions of the alkyl groups grow, the
higher homologues become increasingly soluble in ether, and the taste
becomes sharper and, in some cases, burning.
Behaviour. — (i) Towards dehydrating agents : (a) The 1,2- glycols,
when heated with zinc chloride, P2O5, dilute acids or even water at
3i2 ORGANIC CHEMISTRY
high temperatures, are converted into aldehydes or ketones, e.g.
CH3CH(OH)CH2OH - ^CH3.CH2.CHO and CH3COCH3 (see also the
transformations of the glycols and changes of the pinacones pp. 216,
313). (b) The 1,4- and i,5-glycols yield cyclic oxides (p. 316).
(c) The i,3-glycols form cyclic oxides and also aldehydes and ketones
(M. 23, 60).
(2) Many glycols, especially the primary, when oxidized, pass into
the corresponding oxidation products (see Ethylene Glycol) ; others
break down with fracture of the carbon chains.
(3) On the reactions with halogen acids, nitric acid, concentrated
sulphuric acid, acid chlorides, and acid anhydrides, see esters of the
glycols (p. 319).
I. Ethylene Glycol, Glycol, [i,2-Ethane diol], CH2OH.CH2OH, m.p.
—11*5°, b.p. I97'5°, DO = 1*125, is rniscible with water and alcohol.
Ether dissolves but small quantities of it.
It may be obtained from ethylene through ethylene bromide, ethyl-
ene chlorhydrin (general method of formation, p. 309) or by direct
oxidation ; and also from ethylene oxide by the absorption of water :
CH» CH2.OH
Preparation. — A mixture of ethylene bromide, potassium carbonate and water
is boiled under a reflex condenser, until all the bromide is dissolved (A. 192, 240,
250). Or the «thylene bromide may be converted by heating with anhydrous
potassium acetate into glycol diacetate, which yields glycol when hydrolyzed
with alkali hydroxide (B. 29, R. 287 ; C. 8991, I. 968).
Behaviour. — (i) On heating ethylene gtycol with zinc chloride to
250° water is eliminated and acetaldehyde and crotonaldehyde are
formed ; at 210° with water, only acetaldehyde results.
When ethylene glycol is distilled with 4 per cent, concentrated
sulphuric acid, not only acetaldehyde and ethylidene ethylene ether
(p. 317) are formed, but also Diethylene Oxide. Further treatment
with sulphuric acid or zinc chloride results similarly in the production
of acetaldehyde :
CHa— O— CHa CH..O— CH8 CH3 HOCH,
,OH CH,— O— CH, CH— O— CH, CHO HOCH2
(2) Nitric acid oxidizes glycol to gly collie acid and glyoxal, glyoxylic
acid and oxalic acid. The first oxidation product, glycol aldehyde
(q.v.), is further oxidized too rapidly to be identified :
CH2.OH COOH CHO COOH COOH
CH..OH CH2OH CHO"" ^CHO *" COOH
Glycol. Glycollic Acid.' Glyoxal: Glyoxylic Acid. Oxalic Acid:
^ (3) When glycol is heated with potassium hydroxide to 250°,
it is oxidized to oxalic acid with evolution of hydrogen.
(4) Heated to 160° with concentrated hydrochloric acid, glycol
chlorhydnn results, which at 200° is converted into ethylene chloride.
(5) The latter is also produced when PC16 acts on glycol.
CH
£
DIHYDRIC ALCOHOLS OR GLYCOLS 313
(6) A mixture of nitric and sulphuric acids changes gtycol into glycol
dinitraU.
(7) Concentrated sulphuric acid and glycol yield glycol sulphate.
(8) The acid chlorides or acid anhydrides produce mono- and di-
esters of glycol.
Glycollates :
Metallic sodium dissolves in glycol, forming sodium glycollate, C2H4<C;;-,ST , and
(at 170°) disodium glycollate, C2H4(ONa)a. Both are white, crystalline substances,
regenerating glycol with water. The alkylogens convert them into the corre-
sponding ethers.
Polyethylene Glycols :
Ethylene oxide absorbs water and becomes glycol. The latter and ethylene
oxide unite at 100° in varying proportions, thus yielding the polyethylene glycols :
CH2V CH2OH /CH2CH2OH
>O+ 1 =O< Diethylene Glycol, b.p. 250°.
H/ CH2OH XCH2CH2OH
CH2OH CH2— O— CH2CH2OH
Triethylene Glycol, b.p. 287°.
CH2OH CH2— O— CH2CH2OH
etc.
The polyglycols are thick liquids, with high boiling points. They behave like
the glycols. Ether-acids may be obtained from them by oxidation with dilute
nitric acid ; thus diglycollic acid (q.v.) is formed from diethylene alcohol.
There are two series of homologues of ethylene glycoi ; the one
resulting from alkyl substitution, and the other, including the 1,3-,
i,4-,i,5-glycols, etc., produced by the insertion of an alkyl group
between the carbinol groups.
II. Homologous i,2-glycols.
a-Propylene Glycol, Methyl Ethylene Glycol [Propane diol-i,2],
CH3.CH(OH).CH2.OH, b.p. 188°, D0=roi5, is obtained from pro-
pylene bromide or chloride. It is most readily prepared by distilling
glycerol with sodium hydroxide (B. 13, 1805). Platinum black oxidizes
it to ordinary lactic acid. Only acetic acid is formed when chromic
acid is the oxidizing agent. Concentrated hydriodic acid changes it
to isopropyl alcohol and its iodide. Heated with water at about 190°
it yields propylaldehyde and acetone. It contains an asymmetric
carbon atom, and when exposed to the action of the ferment Bacterium
lermo, becomes optically active (B. 14, 843).
a-Butylene Glycol, Ethyl Ethylene Glycol, C2H6CH(OH).-\
CH2OH, b.p. 192°.
Py-Butylene Glycol, sym.-Dimethyl Ethylene Glycol, Are obtained f rom the
CH3CH(OH).CH(OH).CH3, b.p. 184°. / corresponding butyl-
Isobutylene Glycol, unsym.-Dimethyl Ethylene Glycol, ene bromides-
(CH3)2C(OH).CH2(OH), b.p. 177°. ;
a-Isoamylene Glycol, Isopropyl Ethylene Glycol,\
«^ G/y Are obtained ,0-n the
(CH3)2C(OH).CH(OH)CH3, b.p. 177°. ( corresponding amyl,
fA mylene Glycol, sym.-Ethyl Methyl Ethylene Glycol, ene d
C2H6CH(OH)CH(OH).CHa, b.p. 187°.
Pinacone, Telramethyl Ethylene Glycol, (CH3)2.C(OH).C(OH).(CH8)2+6HtO,
m.p. 42°, anhydrous, m.p. 38°, b.p. 171-172°, is formed, together with isopropyl
alcohol, when sodium or magnesium and mercuric chloride (C. 1906, II. 148)
3i4 ORGANIC CHEMISTRY
act on acetone ; or by electrolysis (B. 27, 454 '> c- I9°°. H. 794) (see method
of formation, No. 8, p. 311). Further, by the action of IMgCH8 on diacetyl
or oxalic ester (mode of formation, No. 6a). It crystallizes from its aqueous
solution in quadratic plates (hence the name, from 7nVa£, plate), and gradually
effloresces on exposure.
In common with other ketones (p. 216), dilute sulphuric or hydrochloric acids
cause it to lose water and undergo intramolecular change, forming pinacoline
or tert.-butyl methyl ketone (p. 224). An isomer of this substance exists —
tetramethyl ethylene oxide (p. 318), which very readily absorbs water forming
pinacone.
Similarly to pinacone, a whole series of tetra-alkylated ethylene glycols can be
prepared by reduction of aliphatic ketones, known collectively as Pinacones,
which behave towards dilute sulphuric and hydrochloric acids as pinacone itself
does. Comp. Methyl Isopropyl Pinacone, C. 1903, II. 23.
sym.-Dipropyl Ethylene Glycol [Octane diol-4,5], C3H7CH(OH).CH(OH)C3H7,
occurs in two modifications ; a-form, liquid, b.p.10 115-120°, /?-form, m.p. 125°,
and is prepared by reduction of butyroin (p. 342) by sodium and alcohol.
ssym.-Dipentyl-ethylene Glyeol [Dodecane diol-6,7], a-form, m.p. 54°, b.p.10
155-160° ; j8-form, m.p. 136°, is produced when capronom is reduced by sodium
and alcohol (C. 1906, II. 1114);
III. i,3-Glycols.
Trimethylene Glycol [Propane diol-i.s], CH,OH.CH2CH2OH, b.p. 216°, D.0=
i '065, is obtained from trimethylene bromide (B. 16, 393) ; or by the fermenta-
tion of glycerol by Schizomycetes, together with w-butyl alcohol (B. 20, R. 706).
It is isomeric with a-propylene glycol. Moderate oxidizing agents produce
fl-Hydroxypropionic Acid or Hydr acrylic Acid; sulphuric acid changes it intopro-
pionaldehyde and acetone (C. 1904, I. 1401).
fi-Butylene Glycol, fi-M ethyl Trimethylene Glycol [Butane diol- 1,3] CH3CH(OH)-
CH2OH, b.p. 207°, is obtained by the reduction of aldol (p. 338) ; 50 per cent,
sulphuric acid converts it into butyl aldehyde and methyl ethyl ketone (comp.
p. 312, and C. 1904, I. 1400).
y-Isoamylene Glycol, aa-Dimethyl Trimethylene Glycol, (CH3)aC(OH).CH2CH2-
OH, b.p. 203°, is obtained from the bromide (B. 29, R. 92).
sym.-Dimethyl Trimethylene Glycol [Pentane diol-2,4], CH3CH(OH)CH2CH-
(OH)CH3, b.p. 199°, is prepared by reduction of hydracetyl acetone (p. 342) ; and
by the action of magnesium methyl iodide on aldol (C. 1904, 1. 1327 ; B. 37, 4730).
aay-Trimethyl Trimethylene Glycol, 2,4-Isohexylene Glycol, (CH3)2C(OH)CH2-
CHaCH(OH)CH3, b.p. 194°, is obtained by reduction of diacetone alcohol (p. 342).
sym.-Tetramethyl Trimethylene Glycol, (CH3)2C(OH).CH2.C(OH)(CH3)2, b.p.13
98°, results from the action of CH3MgI on diacetone alcohol (C. 1902, I. 455 ;
B. 37, 473 1).
A series of higher homologues of the i,3-glycols is obtained from the con-
densation of isobutyl aldehyde with other aldehydes, such as the isobutyl aldols,
by means of alcoholic potassium hydroxide (method of formation No. 50, p. 310).
^-Dimethyl Trimethylene Glyeol, Pentaglycol, (CH3)2C(CH2OH)2, m.p. 129°,
b.p. 206°. Heated with H2SO4 it forms isovaleric aldehyde, isopropylmethyl
ketone and a cyclic oxide (C. 1900, II. 36). aBB-Trimethyl Trimethylene Glycol,
CH2(OH)C(CH8)2CH(OH)CH8, b.p. 207°, and a^-Ethyl Dimethyl Trimethylene
Glycol, m.p. 81°, are obtained from isobutyl aldehyde, and acetaldehyde
and propionaldehyde, respectively. aBB-Isopropyl Dimethyl Trimethylene Glycol,
CH2(OH)C(CH8)2CH(OH)C3H7, m.p. 51°, b.p. 223°, is prepared from isobutyl
aldehyde alone. This substance on oxidation yields first a hydroxy-acid and
then diisopropyl ketone.
sym.'Tetramethyl p-Ethyl Trimethylene Glycol, (CH3)2C(OH)CH(C2H6)C(OH)-
(CH,)2, b.p.n 128°, is obtained from ethyl acetoacetic ester and CH3MgI (mode
of formation 6a, p. 310) (C. 1902, I. 1197).
IV. i,4-Glycols.
Tetramethylene Glycol, [Butane diol-i,4], HO.CH2.CHa.CH2CH2OH, b.p.
202-203°, D = i-oi i, is prepared from tetramethylene dinitramine and sulphuric
acid (B. 23, R. 506) ; also, by reduction of succinic dialdehyde (p. 347), by
aluminium amalgam. It possesses an unpleasant odour of leeks (B. 35, 1187).
UNSATURATED GLYCOLS, OLEFINE GLYCOLS 315
The Diamyl Ether results from the electrolysis of the potassium salt of j8-amyloxy-
propionic acid (C. 1901, I. 613 ; 1905, I. 1698).
a-Methyl Tetramethylene Glycol, (Pentane diol-i,4), CH3.CH(OH)CH2CH2CH2-
OH, b.p.J6 123-126°, with partial decomposition into y-pentylene oxide and water.
It is obtained from acetopropyl alcohol (C. 1903, II. 531) and from yvalerolactone
by reduction (B. 39, 2851).
a-Dimethyl Tetramethylene Glycol, i.^-Isohexylene Glycol, (CH3)2C(OH)CH2-
CH2CHaOH, b.p. 222°, results from the action of CH3MgI on butyrolactone (C.
1907, I. 708).
p-Dimethyl Tetramethylene Glycol, CH2(OH)C(CH3)2CH2CH2OH, b.p.10 123°,
is produced from unsym.-dimethyl succinic ester by reduction with sodium and
alcohol (1905, II. 178).
ao-Dimethyl Tetramethylene Glycol, 2,$-Hexylene Glycol, [Hexane diol-2,5]
CH3CH(OH)CH2CH2CH(OH)CHa> b.p. 217°, is easily obtained by the reduction
of acetonyl acetone by sodium amalgam (B. 35, 1335).
V. i,5-Glycols.
Pentamethylene Glycol, [Pentane diol-i.s], HOCH2.CH2.CH2CH2CH2OH,
b.p. 239°, Dlg=o'994, is obtained frompentamethylene diamine (mode of formation
4, p. 310) (B. 40, 2559). Diamyl Ether is prepared from S-amyloxybutyl bromide,
magnesium and bromomethyl amyl ether (mode of formation 6b., p. 311 ) (C. 1904,
11.587).
a-Methyl Pentamethylene Glycol, [Hexane diol-i,5], CH3CH(OH)[CH2]8CHaOH,
b.p.710 235°, is produced from acetobutyl alcohol (p. 342).
VI. 1,6-, 1,7-, i,8-Glycols, etc.
The melting points of these polymethylene glycols appear to follow the same
rule as those of the normal paraffin mono- and di-carboxylic acids and other
homologous series (p. 48), namely, that those of members possessing an odd
number of atoms lie lower than those of the neighbouring even-numbered members
(C. 1904, II. 1698).
Hexamethylene Glycol, [Hexane diol-i,6], HO[CH2]6OH, m.p. 42°, b.p.
250°, is prepared from hexamethylene dibromide or diacetate ; and from adipic
ester by reduction. Dialkyl Ether is obtained from y-alkoxypropyl halides by
the action of sodium (methods of formation 6b and 8 (p. 311); and from
y-amyloxybutyric acid by electrolysis (B. 27, R. 735 ; C. 1905, I. 1698 ; II. 1701).
Heptamethylene Glycol, Diethyl Ether, C2H6O.[CH2]7OC2H5, b.p. 225°, results
from the interaction of 6-ethoxyhexyl iodide, magnesium and iodomethyl ethyl
ether (mode of formation 6b, p. 311) (C. 1906, I. 4.43).
Octomethylene Glycol, [Octane diol-i,8], HO[CH2]8OH, m.p. 60°, b.p.0 162°.
Enneamethylene Glycol, [Nonane diol-1,9], HO[CH2]9OH, m.p. 45°, b.p.1B 177°.
Decamethylene Glycol, [Decane diol-i.io], HO[CH2]10OH, m.p. 70°, b.p.15 179°.
These glycols are obtained from dicarboxylic esters or amides by reduction
(mode of formation 56, p. 310) (C. 1904, I. 1399 ; 1905, II. 1701).
B. UNSATURATED GLYCOLS, OLEFINE GLYCOLS, ACETYLENE GLYCOLS
Unsaturated dihydric alcohols have been but slightly investigated. The
simplest representatives possible theoretically are not known, and probably are
not capable of existing.
See p. 318, upon the view of furfurane as an oxide of an unknown, unsaturated
glycol. Also consult acetonyl acetone (p. 351).
iso-Dipropionyl, iso-dibutyryl, iso-diisobutyryl, and iso-diisovaleryl are
olefine glycol derivatives. They resulted from the action of metallic sodium on
an ethereal solution of propionyl chloride, butyryl chloride, and isobutyryl
chloride, and iso-valeryl chloride. They are esters of alkyl acetylene glycols
(Klinger and Schmitz, B. 24, 1271 ; B. 28, R. 1000 ; J. pr. Ch., [2], 63, 364).
CnHK.C.OCOCaH,;
Diethyl Acetylene Glycol Dipropionate, Dipropionyl, * - .__ _ V_ , b.p.10
o H
/2 g.'.v-o 5
CHC OCO C H
108°. Di-n-propyl Acetylene Glycol Dibutyrate, Dibutyryl, '7 ' 8T
3I6 ORGANIC CHEMISTRY
b.p-12 119-130°- Diisobutyl Acetylene Glycol Diisovalerate, Diisovaleryl,
(CH3)2.CH.CH2.C— OCOC4H9 145-155°. Butyroin and isovaleroin, the
(CH8)2.CH.CH2.C-O.COC4H9'
corresponding a-ketone alcohols (q.v.), are produced, and not the alkyl acetylene
glycols, when these three compounds are saponified. The diacetate, CH3C-
(OCOCHj) : C(OCOCH8)?CH8, is produced from the di-sodium salt of acetoin
(p. 341) and acetyl chloride.
Hexa-di-ine dial, CH2(OH)C :C-C:C.CHa.OH, m.p. 111°, is a diacetylene
glycol. It is formed by the oxidation of the precipitate from propargyl alcohol
and ammoniacal cupric chloride with potassium ferricyanide (C. 1897, 1, 281 ;
II. 183).
GLYCOL DERIVATIVES
I. ALCOHOL ETHERS OF THE GLYCOLS
A. The alcohol ethers of the glycols are prepared (i ) from the metallic glycolates
and alkyl iodide :
CH2ONa ^ I=N^ CH2OC2H6 Qlycol Monoeihyl Eihey> b p I2?o (B 35>
CHaOH CH2OH
CH2ONa CaH6I CH2OCaH5
+ =2NaI + 1 Glycol Diethyl Ether, b.p. 123°.
CH2ONa C2H6I CH,OC2H6
(2) The monoalkyl ethers of ethylene glycol result from the combination of
ethylene oxide and alcohol.
(3) Dialkyl ethers can be obtained synthetically by means of the methods of
formation 6b and 8 (p. 311) :
(a) From halogen-substituted ethers RO[CH2]n X and Na or Mg ;
(b) From ketones with chloromethyl alkyl ethers and magnesium ;
(c) From alkoxy ketones and alkoxycarboxylic esters with magnesium
alkyl halides.
(d) From alkoxy fatty acid salts by electrolysis. Hydriodic acid de-
composes the neutral ethers into iodoalkyls and glycols (B. 26,
R. 719), which are converted into alkylene iodides by excess of HI.
Hydrobromic acid in the cold converts glycol dialkyl ether into the bromo-
hydrins of the mono-alkyl ether, RO[CHa]nBr (C. 1904, 1. 1400).
The mono-alkyl ethers of tertiary- primary i,2-glycols are changed into alde-
hydes by the action of anhydrous formic or oxalic acid (comp. p. 192).
The polyethylene alcohols are most closely related to the alcohol ethers.
They have been already considered after ethylene glycol (p. 312). Diethylene
glycol bears the same relation to glycol as ethyl ether to ethyl alcohol :
Bne Glycol
(First Ether of Glycol).
B. Cyclic Ethers of the Glycols, Alkylen Oxides.
Diethylene Oxide, O<£^2-£^a>O, m.p. 9°, b.p. 102°, is the second ether of
glycol (see above, Diethylene Glycol). It is obtained from the red, crystalline bromine
addition product of ethylene oxide, (CaH4O)2Bra, m.p. 65°, b.p. 95°, when it is
treated with mercuric oxide. It is also prepared by heating glycol with con-
:entrated sulphuric acid (p. 312). It unites with bromine, forming the above-
mentioned dibromide ; with iodine, to a diiodide, m.p. 85° ; and with sulphuric
acid it forms a sulphate, m.p. 101°. Thus, it forms double compounds or oxonium
salts similar to those of the simple ethers (p. 126) (C. 1907, I. 1103). It is de-
composed into acetaldehyde and glycol when heated with sulphuric acid (p. 312).
Ethylene Methylene Ether, Glycol Methylene Acetal, ^H2'°>CH2, b.p. 78°, is
obtained from trioxymethylene. ethylene glycol and ferric chloride (B. 28, R. 109).
GLYCOL DERIVATIVES 317
or syrupy phosphoric acid (C. 1899, I. 919). Also from glycol, formaldehyde
and hydrochloric acid (C. 1900, II. 1261). Ethylene Ethylidene Ether,
CH2 Q>CH.CH3, b.p. 82'5°, results from the union of ethylene oxide and acet-
aldehyde (comp. p. 312). Diethylene oxide is a cyclic double ether. For the
preparation of this class of substance the i,3-glycols seem also to be suitable (M. 23,
67). Simple cyclic ethers or glycol oxides are also known ; and a third ether,
Ethylene Oxide, c^*-^0 (w^rtz)> is also derived from glycol.
The simple cyclic ethers of the glycols, the alkylene oxides, are readily pro-
duced in various ways, depending upon whether the two OH-groups are attached
to adjacent carbon atoms or not. Alkylene oxides, in which the O-atoms are
in union with adjacent carbon atoms, are termed the a-alkylene oxides, whilst
the others are the /?-, y-, S-alkylene oxides. (i) Ethylene oxide itself and the
ethylene oxides, as well as the /3-alkylene oxides (trimethylene oxide), are pre-
pared by the action of potassium hydroxide on the chlor- or brom-hydrins, the
monohaloid esters of the respective glycols :
(2) The y- and 8-alkylene oxides (y-pentylene oxide, pentamelhylene oxide), are
formed when the glycols are heated with sulphuric acid (B. 18, 3285 ; 19, 2843 ;
M. 23, 67) :
/CH2.CH2OH H2S04 /CH2.CH3V
CH/ - —>CH/ >0+H20.
XCHa.CH2OH NCHa.CH/
The a-glycols, under like treatment, lose water and yield either un-
saturated alcohols, aldehydes, or pinacolines, depending upon their constitution
(pp. 192, 216, 312).
The ethylene oxide ring is easily ruptured, hence ethylene oxide enters into
addition reactions quite as freely as its isomer acetaldehyde. The rings of
tetra- and pentamethylene oxides, however, are far more stable. These can
only be broken up by the halogen acids.
Ethylene Oxide, ?Ha>O, b.p. 12-5°, 0.0=0-898 ,isomeric with acet-
CHa
aldehyde, CH3.CHO, is a pleasantly smelling, ethereal, mobile liquid,
with a neutral reaction, yet able gradually to precipitate metallic
hydroxides from many metallic salts.
CHa.OH OH
=26H;a +Mg<OH
Ethylene oxide is characterized by its additive power, (i) It combines with
water and slowly yields glycol. (2) Nascent hydrogen converts it into ethyl
alcohol. (3) The halogen acids unite with it to form halogenhydrins, the mono-
haloid esters of the glycols ; hydrofluoric acid is, however, an exception (C. 1903,
I. n). (4, a) With alcohol it yields glycol monoethyl ether ; (b) with glycol
it forms diethylene glycol ; (c) and with the latter it combines to triethylene
glycol. (5) It forms ethylene alkylidene ethers (p. 316) with aldehydes. (6)
Acetic acid and ethylene oxide form glycol monacetate, and (7) with acetic anhy-
dride the product is glycol diacetate. (8) Sodium bisulphite changes it to sodium
isethionate. (9) Ammonia changes ethylene oxide to hydroxyethylamine. (10)
With hydrocyanic acid it forms the nitrile of ethylene lactic acid or hydracrylic acid,
from which hydrochloric acid produces the ethylene lactic acid itself. ( 1 1 ) Ethylene
oxide unites with sodium malonic ester (see Hydroxethyl Malonic Ester).
Potassium hydroxide polymerizes ethylene oxide at 50-60° (B. 28, R. 293).
For comparison, the following additive reactions of ethylene oxide and alde-
hyde are arranged side by side :
ORGANIC CHEMISTRY
KHS03 CH2.OH KHSO^ CH ^
l~ ^CH^SO.K
NHs CH2.OH
CH8.CH:0
CH2.NH,
HNC CH..OH
CN
NH3
-> CH3,
HNC
^iH,
CH..CH-
Ethylene oxide and magnesium alkyl halides form addition compounds, which
are converted by heat into primary alcoholates, RCH2CHaOMgX (pp. 107, 185).
Heated with a little potassium hydroxide at 50-60°, ethylene oxide polymerizes
(B.28.R.S95). CH (CH
a-Propylene Oxide, | >O, b.p. 35°. Isobutylene Oxide, \ ,O,
CH.% CH3'
b.p. 51-52°. sym.-Dimethyl Ethylene Oxide, b.p. 56-57°. sym.-Methyl Ethyl
Ethylene Oxide, b.p. 80°. Isopropyl Ethylene Oxide, b.p. 82°. Trimethyl Ethylene
Oxide, b.p. 75-76°. Tetramethyl Ethylene Oxide, b.p. 95-96°, is produced from
tetramethyl ethylene bromide by PbO and water (C. 1902, I. 628). It unites
with water to form pinacone with considerable evolution of heat (p. 313).
Heated to 200-260° with A12O3 or other contact substances, ethylene oxide,
propylene oxide and isobutylene oxide are transformed into the isomeric alde-
hydes, acetaldehyde, propionaldehyde, isobutyl aldehyde, whilst trimethyl
ethylene oxide gives methyl isopropyl ketone (B. 36, 2016).
Trimethylene Oxide, CH,<£^2>O, - b.p. 50°; preparation, see p. 317;
homologues (M. 23, 67 ; C. 1906, II. 1179).
CH2(j9)-CH2(a) x
Tetramethylene Oxide, Tetrahydrofurfurane, )O, b.p. 57°
CH.O^-CHifo) /
(B. 25, R. 912). 2,5-Hexylene Oxide, aa^Dimethyl Tetrahydrofurfurane, b.p. 93°
(B. 35, 1336). aa-Dimethyl Tetramethylene Oxide, b.p. 98° (C. 1907, I. 708),
Diisocrotonyl Oxide, aa^Tetramethy I Tetrahydrofurfurane, b.p. 113°. Diisoamylene
Oxide, aa^Dimethyl-aa-Diethyl Tetrahydrofurfurane, b.p. 160° (C. 1899, 1. 774, 775).
y-Pentylene Oxide, a-Methyl Tetrahydrofurfurane, b.p. 77° (p. 314) (B. 22, 2571).
Pentamethylene Oxide, CH2<£^2~£^2>O, b.p. 82° (B. 27, R. 197).
8-Hexylene Oxide, a-Methyl Pentamethylene Oxide, b.p. 104°, does not unite
with ammonia (B. 18, 3283). The higher polymethylene glycols are converted
into their oxides with difficulty. Decamethylene Oxide, b.p. 181°, has, however,
been prepared, by distilling the chlorohydrin of decamethylene glycol over sodium
hydroxide (C. 1906, II. 596).
Addendum. — Furfurane corresponds with tetramethyl ene oxide. It may be
considered as the cyclic ether of an unknown, unsaturated glycol. It is probable
that this glycol could not exist ; it would be more likely to become rearranged into
succinic dialdehyde, and this in turn to y-butyrolactone (q.v.) :
CH2.CH2OH CHa.CH2v CH=CHOH CH=CHV
I I >0 | | >0
CH2.CH2OH CH2.CH/ CH=CHOH CH=CH/
Tetramethylene Tetramethylene Unknown. Furfurane.
Glycol. Oxide.
By the substitution of sulphur and again of the NH-group for oxygen in
furfurane the products are thiofurfurane, which, from its remarkable resemblance
to benzene, has been called Thiophene, and Pyrrol.
Notwithstanding that the manner of union in the rings of these heterocyclic
compounds is not definitely known, it is possible to refer many bodies to them :
CH=CHX CH=CHV CH=CHV
>0 | >S >NH
CH=CH/ CH=CH/ CH=CH/
Furfurane. Thiophene. Pyrrole.
GLYCOL DERIVATIVES 319
All of them contain rings, and they will be discussed later in conjunction with
related classes of heterocyclic derivatives.
2. ESTERS OF THE DIHYDRIC ALCOHOLS OR GLYCOLS
A. Esters of Inorganic Acids.
(a) Halogen Esters of the Glycols. — The glycols and monobasic acids yield
neutral and basic esters. The dihalogen substitution products of the paraffins
are the neutral or secondary halogen esters of the glycols. The halogen atoms in
them are attached to different carbon atoms. They are isomeric with the alde-
hyde halides (p. 206) and the hetone halides (p. 225), having an equally large
carbon content :
CH2C1 CHoCl CHCL CH.
II II
CHC1 and CHa are isomeric with CH2 and CC1,
CH3 CH2C1 CH3 CHS
Propylene Trimethylene Propvlidene Chloracetol
Chloride. Chloride. Chloride (p. 225).
(p. 206).
The basic or primary haloid esters of the glycols are the halohydrins. These
are obtained :
(1 ) When the glycols are treated with hydrochloric and hydrobromic acids :
CH2OH CH2OH
+ HC1= | +H80.
CH2OH CH2C1
When heated with HI, a more far-reaching reaction occurs. Ethyl iodide
(p. 136) is obtained from ethylene glycol.
The result of the action of HBr on neutral glycol ethers in the cold is the pro-
duction of the ether of the bromhydrin. Like the ether of the chlorhydrin, it can
also be obtained from the benzoyl derivative of the alkoxy-alkylamines by PC1B
or PBr,, with the loss of benzonitrile (comp. p. 320) (B. 38, 960).
(2) They can be obtained, too, by the direct addition of hypochlorous acid
(see Inorg. Chem.) to the olefines, whereby the OH group becomes attached to
the carbon atom poorest in hydrogen (J. pr. Ch. [2] 64, 102, 387 ; comp. C.
1902, I. 1316) :
CH2 CH8C1
|| +HOC1= |
C(CH3)2 C(CH8)2OH
(3) By the action of halogen acids on ethylene oxide and its homologues :
CH2.OH
+HC1=|
CH2C1
(4) Synthetically, it can be prepared from haloid ketones or haloid car boxy lie
esters and alkyl magnesium halides (B. 39, 225, 3678 ; C. 1906, I. 1584, II. 1179) :
CHjCO CH,Mgl (CH3)2COH CHa.CH2I C2H6Mgl CH2CH2I
CH2C1 CH2Cl' C02R (C2H6)2COH
Similarly, a-Chloro-fi-ethoxybutane, C1CH2CH(C2H6O)C2H6 is prepared from
aj8-dichlorethyl ether and zinc ethyl (B. 28, 3111).
Glycol Chlorhydrin, Ethylene Chlorhydrin, CH2C1.CH2OH, b.p. 128°. Glycol
Bromhydrin, b.p. 150°, results also from glycol bromacetin (p. 324) by boiling with
methyl alcohol. Similarly Glycol lodohydrin, b.p.16 78°, is obtained from iodo-
acetin (C. 1901, I. 1356). The iodohydrin is converted completely into acetalde-
hyde when heated with lead hydroxide (C. 1900, II. 31). Trimethylene Glycol
Chlorhydrin, y-Chloro-n-propyl Alcohol, CH2C1.CH8CH8OH, b.p. 160°, is obtained
320 ORGANIC CHEMISTRY
from trimethylene glycol byHCl. a-Propylene Glycol a-Chlorhydrin, CH8CH(OH>-
CH,C1, b.p. 127°, is prepared from alkyl chloride by dilute sulphuric acid ; also
by the addition of HC1O topropylene, a-Propylene Glycol fi-Chlorhydrin,CHdCHCl.-
CH8OH, b.p. 134° (C. 1903, II. 486). Isobutylene Glycol a-Chlorhydrin, (OH)C-
(CH3)2CH2C1, b.p. 129°, is obtained from chloracetone or monochloracetic acid by
Mg(CH3)I ; also from isobutylene and HC1O (C. 1902, I. 1093). Isobutylene
oxide and HC1 gives a mixture of this chlorhydrin and Isobutylene Glycol fi-Chlor-
hydrin (CH3)2CC1.CH2OH, which easily passes into isobutyl aldehyde (B. 39,
2789, 3678).
The primary haloid esters can also be considered as substitution products of
the monohydric alcohols. Glycol chlorhydrin • would be chlorethyl alcohol.
(i) Nascent hydrogen converts them into primary alcohols. (2) Oxidizing agents
convert them into halogen fatty acids, e.g., glycol chlorhydrin yields monochlor-
acetic acid ; trimethylene glycol chlorhydrin yields fi-chloropropionic acid. (3)
They change to alkylene oxides, and partially also into aldehydes, under the
influence of alkalis. (4) Basic esters of the glycols are produced when they
combine with salts of organic acids ; e.g., glycol chlorhydrin and potassium
acetate yield glycol mono-acetate, CH3COO.CH2.CH2OH. (5) Potassium cyanide
changes them to nitriles of the hydroxyacids.
The Ethers of the glycol brom- and iodohydrin can be employed in the building
up of the neutral dialkyl ethers of the higher glycols (comp. p. 310).
In close relation to the halohydrins stand certain substances produced by
the action of mercury salts on ethylene (p. 82), such as Mercury Ethanol Iodide,
HOCH2.CH2HgI, and Mercury Ether Iodide, O(CH2CH2HgI)2. Iodine changes
them to Glycol Iodohydrin (p. 319) and fi-Diiodo-ether, O(CH2CHaI)2. Alkaline
stannic solutions react with mercury ether bromide producing Mercury Diethylene
Oxide, O(CH2.CH2)2Hg, m.p. 145°, a very stable compound, which requires
fuming hydrochloric acid to decompose it, generating ethylene (B. 33, 1641 ;
34, 1385, 2910).
Neutral Haloid Esters of the glycols are very important parent
bodies for the preparation of the glycols (comp. methods i and 4
for the formation of glycols, p. 309).
Methods of Formation. — (i) By the addition of halogens to the
olefines — e.g., ethylene gives rise to ethylene chloride, bromide and
iodide :
CH2 CH2C1 CH2 CH2Br CH2 CH2I
il +C12=| ; || +Bra=| ; || +Ia=| :
CH2 CH2C1 CH2 CH2Br CH2 CH2I
(2) by substitution in paraffins and monohalogen paraffins :
CH3 C12 CH2C1 C12 CH2C1
CH3 CH3 <Fe> ^ CH2Cl'
(3) by the addition of halogen acids to monohalogen olefines.
In this instance much will depend on the temperature, concentration,
and other conditions, as to whether both or only one of the two possible
isomers is formed :
CHBra dil. HBr CHBr Cone. HBr CH2Br .
AH.
(4) by the action of HC1, HBr or HI on glycols and glycol halo-
hydrins. The second OH group will be replaced with more difficulty,
and at a higher temperature, than the first. Similarly, the glycol ethers
(p. 316) are converted into the dihalides by an excess of halogen acid.
(5) Alkylene diamines or halogen alkyl monoamines yield alkylene
dihalides, either by the action of nitrosyl chloride or bromide (C.
1899, 1. 25) ; or better by warming the benzoyl derivative of the amide
ESTERS OF THE DIHYDRIC ALCOHOLS OR GLYCOLS 321
with phosphorus chloride or bromide, and distilling the resulting
imide chloride or bromide (v. Braun, B. 38, 2346 ; 39, 4112) :
The benzoyl derivatives of the cyclic imines, such as benzoyl
piperidine, benzoyl pyrrolidine (comp. p. 335), yield dichloro- and
dibromo-paraffin and benzonitrile by breakage of the ring, under the
action of PC15 or PBr6. This constitutes a convenient method of
preparing i,5-dichloro- and dibromopentane.
(6) by the action of PC15 on glycols :
(7) by the action of KI on alkylene bromides, producing iodides ; and
HgCl2, producing chlorides.
Properties. — The simple dichlor- and dibrom-esters of the glycols,
or olefine dichlorides and dibromides, volatilize without decom-
position. The di-iodides decompose readily in the light, and when
distilled break down into ole fines and iodine. The ethylene dihalides
have a very pleasant odour.
Reactions. — (i) The dihalogen paraffins are converted into ole fines
by sodium :
CH2C1 CHCla 2Na CH,
I and | - > || •
CHaCl CHa CH,
The production of trimethylene from trimethylene bromide and sodium or zinc
is noteworthy :
yCHaBr yCH2
CH,< +2Na=CH2< I +2NaBr.
\CHaBr \CH2
(2) Nascent hydrogen converts both di- and mono-halogen paraffins
into paraffins. This is the reverse of substitution — retrogressive sub-
stitution (p. 93).
(3) When digested with alcoholic potassium hydroxide, halogen
hydride splits off, acid molecules are lost, and monohalogen olefines
and acetylenes or diolefines result (p. 86).
(4) Suitable reagents change dihalogen paraffins into the corre-
sponding glycols (p. 309) or their esters. Heating with water produces
first the mono-halogen hydrines of the glycols, and finally ketones and
aldehydes. The 1,4- and i,5-dihalides yield also cyclic oxides (comp.
M. 23, 64 ; C. 1902, I. 628 ; II. 19 ; 1903, I. 384).
(5) Ammonia produces alkylene diamines.
(6) Potassium cyanide converts them into the nitriles of monohalogen acids
and of the dicarboxylic acids. These are classes of bodies whose connection
with the glycols is indicated by the dihalogen paraffins :
CH2 CH,Br
|| ^ |
CHt CH,Br
CH2.OH
"CH2.OH
CH2.CN ^CH2.COOH
CH2.CN CH2.COOH
Ethylene Ethylene
Cyanide. Succinic Acid.
VOl., I.
322 ORGANIC CHEMISTRY
(7) The alkylene dihalides react with magnesium in ethereal solution
in part similarly to, and in part in a more complicated manner than,
do the simple alkyl halides (p. 185). Ethylene bromide gives ethylene
and magnesium bromide ; in the cold BrCH2CH2MgBr is also obtained.
Trimethylene bromide forms trimethylene (CH2)3 (p. 321), and also
BrMg[CH2]flMgBr, which with CO2 yields suberic acid, HO2C.[CH2]6-
CO2H. Pentamethylene bromide yields, as expected, BrMg[CH2]5MgBr,
and also some BrMg[CH2]ipMgBr. The latter substance, with CO2,
gives decane dicarboxylic acid ; the former, pentane dicarboxylic acid
(pimelic acid) and hexamethylene ketone (B. 38, 1296 ; 40, 3049 ;
C. 1907, II. 681).
rnnTT aCO* co«
[CHJ6<COOH * BrMg[CHJ.MgBr > [CH2]6>CO.
Pimelic Acid. Hexamethylene Ketone.
Ethylene Halides— Ethylene Chloride, Elayl Chloride, Oil of the
Dutch chemists, CH2C1.CH2C1, b.p. 84°, D4=i'28o8, can be prepared
(A. 94, 245) by conducting ethylene into a gently heated mixture of
2 parts of manganese dioxide, 3 parts of sodium chloride, 4 parts of
water and 5 parts of sulphuric acid. It is also prepared from
ethylene diamine and NOC1 ; also from dibenzoyl ethylene diamine
and PC15 (comp. p. 320). It is insoluble in water, has an agreeable
odour, and sweet taste.
Ethylene Bromide, CH2Br.CH2Br, m.p. 9°, b.p. 131°, is formed
when ethylene is introduced into bromine, contained in a wide con-
denser bent at right angles, which is covered with a layer of water (A.
168, 64). It is also produced when ethyl bromide, bromine and iron
wire are heated to 100° (B. 24, 4249).
Ethylene Iodide, CH2LCH2I, m.p. 81°, is formed on conducting
ethylene into a paste of iodine and ethyl alcohol (J. 1864, 345).
History of the Alkylene Halides. — The four Dutch chemists, Deiman, Poets
van Troostwyk, Bondt and Lauwerenburgh, while studying the action of chlorine
on ethylene, first obtained ethylene chloride in 1795 as an oily reaction product.
Hence they called ethylene " gaz huileux," oily gas, a name which Fourcroy
altered to " gaz olefiant," " oil-forming gas " (see Roscoe and Schorlemmer, Org.
Ch., i, 647). This phrase subsequently gave the name " ole fines " to the series.
Balard, the discoverer of bromine, obtained ethylene bromide in 1826 by allowing
bromine to act on ethylene (A. chim. phys. [2] 32, 375). Faraday, in 1821,
prepared ethylene iodide by acting on ethylene with iodine in sunlight.
Propylene Halides, i,2-Dihahgen Propane, CH8CHX.CH2X, and Trimethylene
Halides, i.^-Dihalogen Propane, CH2X.CH2CH2X. The propylene halides
result from the addition of halogens to propylene, and halogen acids to
alkyl halides at 100°. Trimethylene bromide is prepared from ethyl bromide
and hydrobromic acid at —20° and, accompanied by propylene bromide, from
trimethylene and bromine in hydrobromic acid (C. 1899, I. 731 ; 1900, II. 465).
HgCla and KI, change trimethylene bromide into the chloride and iodide.
Propylene Chloride, b.p. 97°; Trimethylene Chloride, b.p. 119°.
Bromide, „ 141° ; „ Bromide, „ 165°.
„ Iodide, decomposes ; „ Iodide, decomposes.
Tetramethyl Ethylene Chloride, (CH8)2CC1.CC1(OH8)2, m.p. 159°, is prepared
from pinacone and HC1 (C. 1900, II. 1061).
Tetramethyl Ethylene Bromide, m.p. 149°, with decomposition, results from
™e action of sunlight on Tetramethyl Ethylene Nitrosobromide, (CH8)2CBr.-
C(NO)(CH8)2. This substance is prepared from tetramethyl ethylene and NOBr
(comp. p. 327) (B. 37, 545). It is a very volatile blue crystalline powder.
OF THE DIHYDRIC ALCOHOLS OR GLYCOLS 323
i,3-Dibromobutane, CH3CHBr.CH2CH2Br, b.p. 147°, is obtained from
rf-butylene glycol (C. 1902, II. 1097).
-2,4-Dibromopentane, CH3CHBr.CH2OHBrCH3, b.p., 63° (C. 1904, I. 1327).
Higher Homologues of the Polymethylene Halide Series are mostly obtained by
the general methods of preparation, Nos. 4 and 5 (p. 320) (J. pr. Ch. [2] 39, 542 ;
B. 27, R. 735 ; 38, 2346 ; 39, 1112 ; C. 1903, I. 583 ; 1904, II. 429 ; 1905, I.
1698 ; 1906, I. 443).
Tetramethylene Chloride, C1[CH2]4C1, b.p. 162°; bromide, m.p. —20°, b.p.I2
82° ; iodide, m.p. 5-8°.
Pentamethylene Chloride, i.^-Dichloropentane, Cl[CH2]fCl, b.p. 177°; bromide,
b.p. 221° ; iodide, m.p. 9°, b.p.tt 149°.
Hexamethylene Chloride, Cl[CH2]6Cl, b.p. 204° ; iodide, m.p. 9-5°, b.p.17 163°.
Heptamethylene Chloride, C1(CH2)7C1, b.p.28 126° ; iodide, m.p. o°, b.p.20 178°.
2,5-Dibromohexane, CH3CHBr.CH2.CH2.CHBrCH3, is prepared from 2,5-
hexylene glycol (p. 315), from Aa-hexane-e-ol (butallyl methyl carbinol), or from
diallyl (p. 190) by means of hydrobromic acid. A mixture of stereoisomeric
forms is obtained, containing a racemic form, m.p. 38°, and the mesoform, a
liquid, b.p.20 100° (B. 34, 2569 ; 35, 1337).
Sodium converts these compounds into cycloparaffins (Vol. II.), just as sodium
and trimethylene bromide produce trimethylene. Sodium malonic esters,
sodium acetoacetic esters, and polymethylene bromides produce cycloparaffin
carboxylic esters (Vol. II.). Mixed, neutral halogen esters of the glycols, con-
taining two different halogen atoms, are also known.
(6) Esters of Mineral Acids containing Oxygen.
Ethylene Nitrate, Glycol Dinitrate, C2H4(O.NO2)2, D, =1-483, is produced on
heating ethylene iodide with silver nitrate in alcoholic solution, or by dis-
solving glycol in a mixture of concentrated sulphuric and nitric acids :
C2H4(OH)8+2HO.N08=C8H4(O.N02)2+2H20.
This reaction is characteristic of all hydroxyl compounds (polyhydric alcohols
and polyhydric acids) ; the hydrogen of hydroxyl is replaced by the NO^-group.
The nitrate is a yellowish liquid, insoluble in water. It explodes when heated
(like nitroglycerine). Alkalis saponify the ester with formation of nitric acid
and glycol.
OH
Glycol Sulphuric Acid, C2H4<Q gQ OH> is produced on heating glycol with
sulphuric acid. It is perfectly similar to ethyl sulphuric acid (p. 139), and
decomposes, when boiled with water or alkalis, into glycol and sulphuric acid.
B. Esters of Carboxylic Acids.
In studying the fatty acids the methods of forming esters with monohydric
alcohols were described. The same methods serve for the production of esters
of the fatty acids with dihydric alcohols or glycols :
(1) from the haloid esters of the glycols: halogenhydrins and alkylene
halides with fatty-acid salts :
CH2OH CH2OH
+CH3C02K=| +KC1;
CH2C1 CH2OCOCH8
(2) from glycols by means of free acids, acid chlorides or acid anhydrides.
(3) There also remains that type of ester formation resulting from the addition
of acids and acid anhydrides to alkylene oxides, just as acid anhydrides add
themselves to aldehydes :
CH2V CHjOCOCH,
L > + (C2H80)80=| ;
CH2OCOCH8
:2H80)80=CHS.CH(OCOCH8)1.
Glycol Diformin, C2H4(O.CHO)2, b.p.28 89°, is prepared from glycol by a
mixture of formic acid and acetic anhydride (C. 1900, II. 314).
Glycol Monacetate, CH2(OH)CH2OCOCH3, b.p. 182°, is a liquid miscible
with water. If hydrochloric acid gas be led into the warmed substance there ia
formed Glycol Chloracetin, Chlorethyl Acetate, CH8C1CH8.O.C2H8O, b.p. 144°.
|
CH
324 ORGANIC CHEMISTRY
Similarly hydrobromic acid produces Glycol Bromaceiate, b.p. 163°. which
yields Glycol lodacetin, b.p.60 no0, when treated with Nal (C. 1901, I. 1356).
Glycol Diacetate, CtH<(O.CJl30)z,b.p. 186°. D0 = i'i28. It dissolves in 7 parts
of water Glycol Distearate, C2H4(OCOC17H3B)2, m.p. 79°, b.p.0 241°. Glycol
Dipalmitate, C2H4(OCOC1,H31)2, m.p. 72°, b.p.. 226° (B 36, 4340)- .
a-Propylene Glycol Diacetate, CH3.C2H3(O.COCH8)2, b.p. 186° ; Tnmethylent
Glycol Diacetate, (CH2)a(OCOCH3)2, b.p. 210°.
The formation of the acid esters is well suited for the detection and deter-
mination of the number of hydroxyl groups in the polyhydric alcohols, the
sugars and the phenols. Benzoic ester particularly is especially easy to prepare.
It is only necessary to shake up the substance with benzoyl chloride and sodium
hydroxide in order to benzoylize all the hydroxyls (B. 21, 2744 ; 22, R. 668,
817). The formation of the nitric acid ester is also well adapted for the purpose
(see Glycol Dinitrate, p. 323) ; also the carbamic ester resulting from the action of
the isocyanic ester (q.v.) ', and especially the phenyl isocyanic ester (q.v.).
For carboxylic esters of unsaturated glycols, see p. 315.
3. THIO-COMPOUNDS OF ETHYLENE GLYCOLS
Compare the sulphur derivatives of the monohydric alcohols (p. 142), the
aldehydes (p. 208), and the ketones (p. 225).
A. Mercaptans.
The mercaptans corresponding with ethylene glycol are formed by treating
monochlorhydrin and ethylene bromide with potassium hydrosulphide.
The Monothio-ethylene Glycol, HSCH2.CH8OH, yields isethionic acid (p. 325)
when treated with nitric acid.
Dithioglycol, Ethylene Mercaptan, Ethylene Thiohydrate, C,H4<|H, b.p. 146°,
Dssi'12, possesses an odour something like that of mercaptan. It is insoluble in
water, and dissolves in alcohol and ether. It shows the reactions of a mercaptan
(B. 20,461).
Trimethylene Mercaptan, HS(CHa)3SH, b.p. 169° (B. 32, 1370).
B. Sulphides.
(a) A Iky I Ethers of the Ethylene Mercaptans : Hydroxy ethyl Ethyl Sulphide,
CH,CH2.S.CH8CH2OH, b.p. 184°. Ethylene Dimethyl Sulphide, CH,S.CHa.-
CHj.SCH,, b.p. 183°. Ethylene Diethyl Sulphide, b.p. 188°.
(b) Vinyl-alkyl Ethers of Ethylene Mercaptan or Sulphuranes : Vinyl Ethyl
Ethylene Mercaptan, CHa:CH.SCH2CHaS.CaH8, b.p. 214°. For its formation, see
the sulphine compounds, which are treated later on.
(c) Thiodiglycol, HOCHaCH,.S.CHaCHaOH, corresponding with diglycol, is
also known (B. 19, 3259). However, the simple ethylene sulphide, correspond-
ing with ethylene oxide, is not known, whilst Diethylene Oxide Sulphone,
O<rTTS r,TTa'>SO2, m.p. 130°, corresponding with diethylene oxysulphide, as
^utia — (^t±2
well as Diethylene Disulphide, are known.
(d) Cyclic Sulphides: Diethylene Disulphide, S^^'ZcH^8' m'P' II2°'
b.p. 200°, is formed from ethylene mercaptan, ethylene bromide, and sodium oxide.
When ethylene bromide is digested with alcoholic sodium sulphide, a polymeric
ethylene sulphide, (C2H4S),, m.p. 145°, is produced at first. This is a white,
amorphous powder, insoluble in the ordinary solvents, which protracted boiling
with phenol changes to diethylene disulphide (A. 240, 305 ; B. 19, 3263 ; 20, 2967).
Trimethylene Disulphide, CH2< 2-, m.p. 75° (B. 32, 1370).
CHjS
(e) Ethylene Mercaptals and Ethylene Mercaptols are similarly produced from
ethvlene mercaptan by the action of aldehydes, ketones, and HC1, just as the
jnercaptals (p. 209) and the mercaptols (p. 226) are obtained from mercaptans
(B. 21, 1473).
CH2Sv
Ethylene Dithioethylidene, \ >CH.CH8, b.p. 173*.
CHjS/
•
HO-COMPOUNDS OF THE ETHYLENE GLYCOLS 325
CHaS— SCH2
(/) Diethylene Tetrasulphide, \ \ , m.p. 150°, is produced by the
CH2S— SCH2
action of the halogens, or sulphuryl chloride or hydroxylamine on ethylene
mercaptan. It is a white, amorphous powder (B. 21, 1470).
C. Sulphine Derivatives.
Ethyl iodide and diethylene disulphide unite to form Diethylene Disulphide
»H»
Sulphine Ethyl Iodide,
CHa.S.C2aH6
Ethyl Sulphurane, | , is produced on distilling the above-mentioned
CHj.S.CjH.
iodide with sodium hydroxide. The closed ring of diethylene disulphide is
broken.
The union of the derivatives of diethylene disulphide with the higher alkyl
iodides yields homologous compounds known as sulphuranes. They are the
alkyl vinyl thio-ethers of ethylene (B. 19, 3263 ; 20, 2967 ; A. 240, 305).
D. Sulphones.
The disulphones are produced when the open and the cyclic disulphides are
oxidized by potassium permanganate. All sulphones, in which sulphone groups
are attached to two adjacent carbon atoms, can be hydrolyzed (Stuffer's law,
B. 26, 1125).
CH2.S02.C2H6
(a) Open Sulphones : Ethylene Diethyl Sulphone, I , m.p. 137°,
CH2.SO2.C2H6
has been obtained (i) from ethylene dithioethyl ; (2) from ethylene bromide
by the action of sodium ethyl sulphinate, and (3) from sodium ethylene di-
sulphinate by the action of ethyl bromide. The hexivalence of sulphur in the
sulphones is thus proved (B. 21, R. 102).
(b) Cyclic Sulphones (B. 26, 1124 ; 27, 3043) : Trimethylene Disulphone,
m.p. 204-205°, results from the oxidation of methylene dithioethylene. Barium
hydroxide solution decomposes this into Hydroxyethyl Sulphone Methylene Sul-
phinic Acid. This, on boiling with water, forms first an internal anhydride, b.p.
164°, which then loses SOa and turns into Hydroxymethylene Sulphone, m.p. 20°.
CH8— S0av CH2OH CH20 . SO CH2OH
| >CHa - M - M I - >\ '
CH2— SO/ CH2.S02CH2S02H CH2SOa.CHa CH2SO2CH8
Trimethylene Hydroxyethyl Sulphone Hydroxyethyl
Sulphone. Methylene Sulphinic Acid. Methyl Sulphone.
The sulphinic lactone gives, on oxidation, Hydroxyethyl Sulphone Methylene
CHa— O— SOa
Sulphone Lactone, \ \
CH2.SOa.CHa
CHa— SOa— CH,
Diethylene Disulphone, \ \ , results from the oxidation of diethy-
CHa— Spa— CHa
lene disulphide, and decomposes similarly to trimethylene disulphone.
E. Sulphonic Acid.
Isethionic Acid, Ethylene Hydrinsulphonic Acid, Hydroxyethyl
CH2.OH
Sulphonic Acid, \ , is isomeric with ethyl sulphuric acid,
CH2.S03H
C2H5O.SO3H, and is produced (i) by oxidizing monothioethylene
glycol with HNO3 ; (2) by the action of nitrous acid on taurine
or amidoisethionic acid (comp. formation of glycollic acid from
glycocoll, p. 362) :
H,N.CHaCHaSO,H+HONO=HO.CHaCHaSO,H-f-N,+H,O.
326 ORGANIC CHEMISTRY
(3) by heating glycol chlorhydrin with potassium sulphite ; (4) by
boiling ethionic acid (p. 327) with water (B. 14, 64 ; A. 223, 198) ;
(5) from ethylene oxide and potassium hydrogen sulphite.
Isethionic acid is a thick liquid, which solidifies when allowed to stand over
sulphuric acid. Its salts are very stable and crystallize well. Chromic acid
oxidizes isethionic acid to sulpho-acetic acid.
The barium salt is anhydrous ; ammonium salt forms plates, m.p. 135°, and
at 210-220° it changes to the ammonium salt of di-isethionic acid, O(CH2.-
CH.SO.NH4)3 (B. 14, 65). Ethyl Isethionate, b.p. 120° (see B. 15, 947)-
PC16 converts the acid into Chlorethyl Sulphonic Chloride, C1.CH2CH2SO2C1,
b.p. 200°. It is also formed by heating ethane disulphochloride. When it is
boiled with water it is converted into Chlorethyl Sulphonic Acid, CHaCl.CHa.SO3H
(A. 223, 212).
Taurine, Aminoisethionic Acid, Aminoethyl Sulphonic Acid,
CH2NHt CH2.NH3
| or | I , m.p. about 240 , with decomposition, was
CHa.S03H CHa.S08
discovered by Gmelin in 1824; its sulphur content, which had
previously been overlooked, was detected in 1846 by Redtenbacher.
It is considered in this connection because of its intimate relationship
to isethionic and chlorethylene sulphonic acids. It occurs as tauro-
cholic acid, in combination with cholic acid, in the bile of oxen (hence
the name — ravpos, ox) and many other animals, and also in the different
animal secretions.
It is formed when taurocholic acid is decomposed with hydro-
chloric acid :
CHa.NH(C24H3904) HCl CH2.NHa
1 - > | +C24H400§.
CH2S03H H«° CH2.S03H
Taurocholic Acid. Taurine. Cholic Acid.
It can be prepared artificially by heating chlorethyl sulphonic acid,
CH2C1CH2S03H, with aqueous ammonia (Kolbe, 1862, A. 122, 33).
This synthesis presupposes that of ethylene or ethyl alcohol (p. in). Both
substances combine with SO8 to give carbyl sulphate, a derivative of isethionic
acid. The following diagram shows the course of the synthesis :
CH2.OH aS03 CH2.OS(V Ha° CH2.O.SO3H H2O CHa.OH
2. 3 2.
CH, CH8.S02 /
, 8.2 Cold CH2S08H Hot CH2.SO3H
Alcohol. Carbyl Sulphate. Ethionic Acid. Isethionic Acid.
acid.
CH2.C1
CH2S02C1 CH2.S02OH CH2.SO3H
Chlorethyl Sul- Chlorethyl Sulphonic Taurine.
phonic Chloride. Acid.
Taurine also results when ethylenimine is evaporated together with sulphurous
Taurine crystallizes in large, monoclinic prisms, insoluble in alcohol,
but readily dissolved by hot water. It contains the groups NH2 and
S08H, and is, therefore, both a base and a sulphonic acid, but as the
NITROGEN DERIVATIVES OF THE GLYCOLS 327
two groups neutralize each other, the compound has a neutral reaction.
It may, therefore, be considered as a cyclic ammonium salt, as indicated
in the second constitutional formula. It can form salts with the
alkalis. It separates unaltered from its solution in acids (see Glycocoll) .
Nitrous acid converts it into isethionic acid (p. 325). Boiling
alkalis and acids do not affect it, but when fused with potassium
hydroxide it breaks up according to the equation :
NH2CH2CH2S03K+2KOH=CH3C02K+KaSO,+NH34Ha.
CHa— NH
Anhydrotaurine, \ \ , m.p. 88°, is formed by the action of ammonia
CHa— SO 2
on chlorethane sulphochloride, or on ethane disulphochloride (C. 1898, I. 20).
Taurine introduced into the animal economy reappears in the urine as Tauro*
carbamic Acid, NH2CONH.CH2.CH2.SO8H.
CH2 N(CH3)S
Taurobetaine, \ , is prepared by methylating taurine, and is
CHa— SOaO
analogous to betaine (q.v.).
Ethionic Acid, C2H4<g^^3H. The constitution of this acid would indicate
it to be both a sulphonic acid and primary sulphuric ester. It is therefore
dibasic, and on boiling with water readily yields sulphuric and isethionic acids.
It results when carbyl sulphate takes up water.
CHa— O— S0av
Carbyl Sulphate, \ }O, the anhydride of ethionic acid (A. 223, 210),
CH2 SO/
is formed when the vapours of SO, are passed through anhydrous alcohol. It
is also produced by the direct union of ethylene with two molecules of SO3.
CH2.SO,H
Ethylene Disulphinic Acid, Ethane Disulphonate, \ , m.p. 100°, may
CHrSO,H
be prepared from glycol mercaptan and ethylene thiocyanate by means of con-
centrated nitric acid ; by the action of fuming sulphuric acid on alcohol or
ether ; or by boiling ethylene bromide with a concentrated solution of potassium
sulphite. It is easily soluble in water. Reduction with zinc dust, see B. 38,
1071.
Ethane Disulphochloride, SO2Cl.CH2.CHa.SO±Cl, m.p. 98°, by the action
CH2SOaH
of zinc dust, forms the zinc salt of Ethylene Disulphoinic Acid, \ . The
CH2SO2H
disulphochloride, similarly to the homologous chloride of i,2-Propane Disulphonic
Acid, CH3CH(SO2C1)CH2SO2C1, m.p. 48°, easily gives up SO2 (comp. p. 147,
Anhydrotaurine, Vinyl, and Propenyl Sulphonic Acid) ; whilst the chloride of
Trimethylene Disulphonic Acid, CH2(CH2SO2C1)2, is more stable (B. 34, 3467 ;
36, 3626), and behaves in accordance with Stuffer's rule (p. 325).
4. NITROGEN DERIVATIVES OF THE GLYCOLS
A. Nitroso-compounds.
The addition-products of the defines with nitrosyl chloride belong to this
group (comp. the Terpenes, Vol. II.).
Tetramethyl Ethylene Nitrosyl Chloride, (CH8)2C(NO).CC1(CH8)2, m.p. 121°, is
prepared by adding sodium nitrite to tetramethyl ethylene in an alcoholic
solution of hydrochloric acid in the cold (B. 27, 455 ; R. 467). It has a blue
colour, and a somewhat penetrating camphor-like odour.
See also Tritnethyl Ethylene Nitrosite, (CH8)aC(ONO).CH(NO)CH8, and Ni-
trosate, (CH8)2C(ONO2).CH(NO)CH8 (p. 345).
B. Nitre-compounds.
Only one nitro-derivative of glycol — the primary body — is known. The
monoiiitro- compounds can be looked on as being nitro-substitution products
328 ORGANIC CHEMISTRY
of the paraffin alcohols, and are known under the name of nitro-alcohols. They
are prepared by the interaction of the halohydrines and silver nitrite, and from
the primary mononitro- paraffins by condensation with aldehydes by means of a
dilute solution of potassium bicarbonate or alkali hydroxide (C. 1899, I. «54)-
Nitroethyl Alcohol, Glycol Nitrohydrin, CH2(NO2).CH2.OH, b.p.8i 120°,
is a heavy oil. 2-Nitropropyl Alcohol, CH3CH(NO2)CH2OH, b.p.2a 121°.
Nitroisopropyl Alcohol, CH8.CH(OH)CH2NOa, b.p.80 112°, D18=i-i9i (B. 28,
R. 606) (see also Nitro-olefines, p. 151). $-Nitropropanol, HO.CH2.CHa.CH2NO2,
b.p.81 139°. For nitro-alcohols containing 4,5, and 6 carbon atoms, see C. 1897,
II. 337 ; 1898, 1. 193. ForDinitro- andHalogen-nitro-compounds, corresponding
with the glycol series, see pp. 151, 155.
C. Amines and Ammonium Compounds of the Glycols.
There are two series of amines, derived from the glycols, and
corresponding with the two series of glycollates, esters, mercaptans,
etc.:
HO.CH2CH2.OH, HO.CH2CH2.NH2, and NH2.CH2CH2.NHt.
Glycol. Hydroxyethylamine. Bthylene Diamine.
Therefore the amines of the glycols fall into two classes : (i) The
hydroxyalkylamines and their derivatives ; (2) the alkylene diamines
and their derivatives.
(a) Hydroxyalkyl Bases, or Hydramines and their derivatives. —
Methods of formation : (i) action of ammonia on the halohydrins ;
(z) by the union of ammonia and alkylene oxides in the presence of
water (B. 32, 729; C. 1900, II. 1009). In these two reactions the
products are primary, secondary, and tertiary hydroxyalkyl bases, e.g. :
CHav CH2.OH
>O+NH«=| Hydroxyethylamine or Aminoethyl Alcohol (p. 117).
CH/ CH2.NHa
2 | a/O+NH8=^2(OH).CH8>NH DihydroxyethylammeorlminoethylAlcohol.
CH2X CH,(OH).CH8v
3 | >0+NH8=CH2(OH).CH,-^N Trihydroxyethylamine or Azoethyl Alcohol.
CH/ CH2(OH).CHX
These three bases are best separated by distillation under reduced
pressure (B. 30, 909). They were discovered by Wiirtz and closely
investigated by Knorr.
(3) by reduction of nitro-alcohols (see above) hydroxyacid nitriles,
amino-ketones or isonitroso-ketones (B. 33, 2829, 3169) ;
(4) by the action of sulphuric acid on allylamine with addition
of water (B. 16, 532) :
(5) by the application of the phthalimide reaction (p. 159). Alky-
lene halides are allowed to act on potassium phthalimide, the re-
action-product being heated with sulphuric acid to 200-230° :
C.H1|CO>NK->C.H,{CO>NCHj .CH>Br_M.iHi{COOH +NH,CHtCH,OH
On the course of the reaction of the alkaline decomposition of the
bromalkyl phthalimides, see B. 38, 2404.
(6) The dialkylated hydroxyethylamine bases are also known as
alkammes, and their carboxylic esters as alke'ines (such as tropeiine) (B.
15, 1143). Alkamines are obtained from the halogen hydrines and
NITROGEN DERIVATIVES OF THE GLYCOLS 329
secondary amines ; also from dialkyl amino-acetic esters and mag-
nesium alkyl halides (B. 39, 810) :
q,H8MgI
(CaH6)aN.CH2.COOC2H5 > (C2H5)2N.CHaC(C2H5)2OH.
Some are possessed of physiological action (comp. C. 1904, I.
1195 ; 1906, I. 1584).
The hydroxyethylamine bases are separated by fractional crystallization of
their HC1 salts, or platinum double salts. They are thick, strongly alkaline
liquids, which decompose upon distillation.
Hydroxyethylamine, Amino-ethyl Alcohol [Aminethane-2-ol] [Ethanolamine],
CH2(OH)CHjNH8, b.p. 171°, and the homologous series of the Hydroxyethyl
Alkylamines, CH2(OH).CH2(NHR) and CH2(OH)CH2(NRa), are best prepared
by the addition of ammonia or the corresponding primary and secondary amines
to ethylene oxide in aqueous solution (A. 315, 104; 316, 311). Hydroxyethyl
Dimethylamine, CH2(OH).CH2N(CH3)2, is also obtained by the breaking down
of methyl morphimethin (Vol. II. : Alkaloids), (B. 27, 1144).
Choline, Hydroxyethyl Trimethy I Ammonium Hydroxide, Bilineurine,
Sincalin, HOCH2.CH2.N(CH3)3OH, is quite widely distributed in the
animal organism, especially in the brain, and in the yolk of egg, in
which it is present as lecithin, a compound of choline with glycero-
phosphoric acid and fatty acids. It is present in hops, hence it occurs
in beer. It has also been found in the plant Strophanthus. It
is obtained, also, from sinapin (the alkaloid of Sinapis alba), when it
is boiled with alkalis (hence the name sincalin). It occurs, together
with muscarine, (HO)2CHCH2N(CH3)3OH(?) (B. 27, 166), in fly agaric
(A rgaricus muscarius) .
History. — A. Strecker discovered this base (1862) in the bile of swine and
oxen. He gave it the name choline, from xoA.^, bile. Liebreich obtained it from
protagon, a constituent of the nerve substance, and at first named it neurine,
from vfvpov, nerve ; this he later changed to bilineurine, to distinguish it from
the corresponding vinyl base, which continued to bear the name neurine. The
constitution of choline was explained by Baeyer, and Wurtz showed how it might
be synthetically prepared by the action of trimethylamine on a concentrated
aqueous solution of ethylene oxide :
CH2\ CH2OH
| >0+H20+N(CH3)3=|
CH/ CH2N(CH3)3OH.
Its hydrochloride is produced from ethylene chlorhydrin and
trimethylamine. Ethylene bromide and trimethylamine at 110-120°
produce bromethyl trimethyl ammonium bromide, which on heating
with water at 160°, gives choline hydrobromide, HOCH2CH2N(CH)3Br
(B. 36, 2901).
Choline deliquesces in the air. It possesses a strong alkaline
reaction and absorbs CO2. Its platinum double salt, (C5H14ONC1)2.-
PtCl4, crystallizes in beautiful reddish-yellow plates, insoluble in
alcohol. See B. 27, R. 738, for choline derivatives.
Isocholine, CH3CH(OH)N(CH3)3OH, is obtained from aldehyde-ammonia
(B. 16, 207). Homocholine, HOCH2CH2CH2CH2N(CH3)3OH (B. 22, 3331).
Neurine, Vinyl Trimethyl Ammonium Hydroxide, CHa:CH.N(CH3)3OH, re-
sembles choline, from which it is produced when choline undergoes putrescent
decomposition or when boiled with barium hydroxide solution. It has also
33o ORGANIC CHEMISTRY
been obtained from the brain substance. It occurs with the ptomaines—
alkaloids of decay of proteins, particularly in animal bodies. It may be derived
from the bromide corresponding with choline (obtained by treating ethylene
bromide with trimethylamine), and the iodide (resulting from the action of HI
on choline) when they are subjected to the action of moist silver oxide :
CH..OH 2HI CH2I Ag20 CHa
I ^~ I i i. - ^- II
CHaN(CH3)3OH CH2N(CH3)3I H2° CHN(CH3)3OH.
Choline. Neurine.
Contrary to choline, which is harmless, neurine is exceedingly poisonous.
CO - O
BetaYne, Trimethyl Glycocoll, Oxyneurine, Lycine, \ -| ,is
CH2 — N(CH8)3
allied to choline and neurine, from which it is obtained by oxidation
(Liebreich, B. 2, 13) :
CHaOH 20 COOH -H20 CO-0
I - > I - - — > I I
CHaN(CH3)3OH CHaN(CH3)3OH CH2N(CH3)8.
Choline. Betaiue.
As it is a derivative of amino-acetic acid it will be more closely
examined, in company with other betai'nes, with the amino-fatty
acids.
p-Amino-ethyl Ether C2H5OCH2CH2NH2, b.p. 108°, is obtained
from jS-chlor-or j8-brom-ethylamine by means of sodium alcoholate.
p-Dimethylamine Ethyl Ether, C2H5OCH2.CH2N(CH3)2, b.p. 121°,
occurs in the break-down products of various morphine bases (Vol. II. :
Alkaloids) (B. 37, 3504 ; 38, 3150).
Dihydroxyethylamine, NH(CH2CH2OH)2, m.p. 28°, b.p.100 270°, is
prepared from ethylene oxide and dibromodiethylamine.
ft-Diaminoethyl Ether, O(CH2CH2NH2)2, b.p. 183-184°, is obtained
by the break-down of its diphthalyl derivatives, which, in turn, are
prepared from diido-ether and 2 molecules of potassium phthalimide
(B. 38, 3411).
Diethyleneimide Oxide, Morpholine, O<a'2>NH, is produced when
dihydroxyethylamine is heated to 160° with sulphuric acid, and distilled with
potassium hydroxide; also, from diiodo-ether (pp. 129, 320) and toluene sulpho-
namide (Vol. II.), and subsequent decomposition of the toluene sulphomorpholine
formed (B. 34, 2606). See B. 22, 2081, for homologous morpholines. It is
assumed that the same atomic grouping exists in morphine as in morpholine,
hence the name.
Trihydroxyethylamine, N(CH2CH2OH3), b.p. 278°, i-Amino-2-propanol,
CH,CH(OH).CH2(NHa), b.p. 161°; i-Amino-2-butanol, CH3CHaCH(OH)CH2.NH2,
b.p. 204°, 2-Amino-3-pentanol, CH,CH2CH(OH)CH(NH2)CH3, b.p. 174°, etc.,
are prepared by reduction from the corresponding nitro-alcohols ; i-Amino-2-
propanol and 2-Amino-^-butanol, CH3CH(OH)CH(NH2)CH3, also from the
corresponding isonitroso-ketones ; i-Amino-2-butanol and 2-Amino-^-pentanol
also from the corresponding amino-ketones (B. 32, 1905 ; 33, 3169 ; 37, 2480 ;
C. 1902, I. 716, 717).
i-Amino-4-butanol, CH2(OH).[CHa]aCH2(NHa), b.p. 206°, is produced from
y-cyanopropyl alcohol by sodium and alcohol (B. 33, 3170); methyl ether
(B. 32, 948).
Diacetone Alkamine, (CH3)2C(NH2).CH2CH(OH)CH3, b.p. 175°, results on
reducing diacetonamine (p. 230) (A. 183, 290 ; B. 30, 1318).
For homologous alkamines, see also B. 14, 1876, 2406; 15, 1143 ; 28, 3111 ;
29, 1420, etc.
(6) Halogen Alkylamines, or Haloid Esters of the Hydroxyalkylamines.— In
NITROGEN DERIVATIVES OF THE GLYCOLS 331
the free state these bodies are soluble in water and not very stable. They easily
change to salts of the cyclic imines, e.g. chloramylamine, C1CH2(CH2)4NH2,
becomes pentamethyleneimide or piperidine hydrochloride, CHa.(CH2)4NH.HCl.
On the transformation of tert.-p- and y-chloralkylamine into piperazonium
bromide, see p. 337. Methods of Formation : (i) The addition of a halogen
acid to unsaturated amines, like vinyl- or allylamine, p. 166 (B. 21, 1055 ;
24, 2627, 3220 ; 30, 1124).
(2) By the action of halogen acids on hydroxyalkylamines.
(2.0) By mixing the nitriles of the halogen substituted acids with sodium
phenolate, reducing and heating with a halogen acid (B. 24, 3221 ; 25, 415) :
Cl.CHaCH,CH2CN+NaOC8H6=C.H6Q.CH2CH2CH2CN+NaCl
4H aHCl
C6H6OCH2[CH2]aCN - X:6H6.OCH2[CH2]aCH2NH2 - X;iCH2[CH2]3NH2.HCl.
(3) From imidochlorides, which result from the action of PC16 on the alkylene
dibenzoyl diamines (p. 321), by distillation under reduced pressure (B. 38,
(4) When the halogen alkyl phthalimides are heated with halogen acids (B.
21, 2665 ; 22, 2220 ; 23, 90), e.g. :
Bromethyl Phthalimides. o-Phthalic Acid.
The following are known :
Chlor-, brom-, iodo-ethylamine, ICH2CH2NH2 ; transformation of bromethyl-
amine into ethylene imide, see p. 355. fi-Chlorethyl Dimethylamine, C1CH2CH2N.-
(CH3)2, b.p. 110°, is an oil. Its aqueous solution changes on keeping or evapora-
tion into tetramethyl piperazonium chloride (p. 336) (B. 37, 3507). fi-Bromo-
propylamine, CH3CHBrCH2NH2, results from boiling allyl mustard oil with
hydrobromic acid, and is obtained as a hydrobromide (B. 32, 367). y-Chloro-
propyl Dimethylamine, C1CH2CH2CH2N(CH3)2, b.p. 135° (B. 39, 1420). y-Bromo-
propylamine, BrCH2CHaCH2NH2. fi-Bromobutylamine, CH3CHaCHBrCH2-
NH2. y-Chlorobutylamine, CH3CHC1.CH2CH2NH2 {B. 28, 3111). 8-Chhro-
butylamine, C1CH2[CH2]2.NH2. e-Chloroamylamine, ClCH2[CH2]4NHa. B-
Methyl-e-chhro-n-amylamine, CH2C1[CH2] 2CH(CH3)CH2NH2. p-n-Propyl-e-
chloro-n-amy lamine, CH2C1[CH2]2CH(C3H7)CH2NH2 (B. 27, 3509; 28, 1197).
The four last compounds lose HC1 and form tetramethylene imine and
pentamethylene imine (p. 336) ; or piperidine, pipecoline, and j8-propyl
piperidine.
6-Chlorohexylamine, C1[CH2]6NH2, and 'j-Chloroheptylamine, C1[CH2]7NH2,
with 5-chloroamylamine, are obtained from the alkylene dibenzimide chlorides
(method above), and, like it, yield a cyclic imide (p. 334).
Dibyomodiethylamine, NH(CH2CH2Br)2 (B. 30, 809).
(c) Sulphur derivatives of Hydroxyethylamine. Aminoethyl Mercaptan Hydro-
chloride, HC1.NH2.CH2CH2SH, m.p. 71°. Thiodiethylamine, (NH2CH2CH2)2S,
b.p. 232° (comp. Ethylene Imine, p. 335). Diaminoethyl Disulphide Hydro-
chloride, (NH2CH2CHaS).2HCl, m.p. 253°. Diaminodiethyl Sulphone, (NH2CH2-
CH2)2SO2, and Diaminosulphonal, (NH2.CH2CH2SO2)2C(CH3)2, m.p. 85°, are
prepared from bromethyl phthalimide (B. 22, 1138; 24, 1112, 2132, 3101;
35, 1372).
Taurine, Aminoisethionic Acid, NH2CH2CH2SO3H, has akeady
been discussed under isethionic acid (p. 325).
II. Alkylene Diamines. — The di-, like the monovalent alkyls, can replace
two hydrogen atoms in two ammonia molecules and produce primary, secondary,
and tertiary diamines. These are di-acid bases, and are capable of forming
salts by direct union with two equivalents of acids. Some of them have been
detected with the ptomaines or alkaloids of decay (B. 20, R. 68) and are therefore
worthy of note, e.g. tetramethylene diamine, and pentamethylene diamine or
cadaver inc.
ORGANIC CHEMISTRY
Formation : (i) They are prepared by heating the alkylene bromides with
alcoholic ammonia to 100° (p. 157) in sealed tubes :
**
BrCH2.CHsBr4-2NH8=C2H4<».2HBr
Ethylene Bromide. Etbylcne Diamine.
Diethylene Diamine,
3BrCHaCHaBr+6NH8=N^c!H^N.2HBr+4NH4Br.
Triethylene Diamine.
To liberate the diamines, the mixture of their hydrobromides is distilled with
KOH and the product is then fractionated.
(2) Another very convenient method for the preparation of diamines is the
reduction of (a) alkylene dicyanides or nitriles of dicarboxylic acids (q.v.) with
metallic sodium and absolute alcohol (see p. 158 and B. 20, 2215) :
CN CH8NH8 CH2.CN CHa.CH2.NH8
| +8H=| ; I +8H=|
CN CH2NHa CH2.CN CH2.CH2.NHa.
Dicyanogen. Ethylene Ethylene Tetramethylene
Diamine. Cyanide. Diamine.
(b) By the reduction of the oximes, (c) of the hydrazones of the dialdehydes
and diketones, and (d) of the dinitroparamns.
In some of these reductions cyclic imines have been observed ; thus, in the
reduction of ethylene cyanide in the presence of tetramethylene diamine, tetra-
methylene imine is formed.
(3) From dicarboxylic amides, bromine and alkali hydroxide (B. 27, 511)
(P- T59)'
(4) From dicarboxylic azides (J. pr. Ch. [2], 82, 189).
(5) From alkylene diphthalimides on heating with HC1:
f £ IHJ^W^xrrru •» xiV^^iHr' TJ * '
Trimethylene Diphthalimide. Trimethylene Diamine Hydrochloride.
(6) From diamino- mono- and -di- carboxylic acid, by dry distillation (C. 1905*
II. 463) :
CHa.CH2.CH(NH8)COOH CHaCH2CHaNHa
I = | +2CO,.
CHa.CHa.CH(NHa)COOH CHaCHaCH2NH2
Properties. — The alkylene diamines are liquids or low melting solids of
peculiar odour, which, in the case of those that are volatile, resembles that of
ammonia, and recalls that of piperidine. They fume slightly in the air, and
absorb carbon dioxide. It is found that the melting points of the homologous
series are not regular in their increase, but those of members containing an even
number of C atoms are higher than of those containing an uneven number. The
boiling points, on the other hand, show a regular increase (J. pr. Ch. [2] 62,
192 ; C. 1901, I. 610).
Reactions. — Alcohol and acid radicals can be introduced into the amino-
groups of the diamines in the same manner as in the amino-groups of the mon-
amines (Action of formaldehyde, see B. 36, 35). The production of the dibenzoyl
derivatives, e.g. C8H4(NHCOC6H6)a, upon shaking with benzoyl chloride and
sodium hydroxide, and the formation of phenyl ureas, (CHa)w(NHCOC,H6)2, by the
action of phenyl cyanate, is well adapted for the detection of the diamines
(B. 21, 2744 ; C. 1905, I. 274). On the conversion of the alkylene dibenzoyl
diamines into chloralkylamines and alkylene dichlorides, see p. 320. Nitrous
acid converts them into glycols, at the same time unsaturated alcohols and
unsaturated hydrocarbons arise (B. 27, R. 197).
Further, the diamines unite directly with water, forming very stable ammonium
„ /(i)CONMrrH , M^-CO(i)\r „ a v 2C8H4(C02H)a
H«((2)CO>N[CHa]3N<CO(2)/C«H« 4Hao > HCl.NHaCHICHaCH2NHa.HCl
NITROGEN DERIVATIVES OF THE GLYCOLS 333
oxides, which only give up water again when they are distilled over potassium
hydroxide (comp. Pentamethylene Diamine) :
CHaNHa CHaNH, v
+H.O= I >O, Ethylene Diamine Hydroxide.
CHaNHa CHa.NH3/
By loss of ammonia they pass into cyclic imines.
Ethylene Diamine, caH4<NH8' m'p' 8'5°' btp' Il6'5°» combines with water
to form Ethylene Diamine Hydroxide, m.p. 10°, and b.p. 118°. It reacts strongly
alkaline, and has an ammoniacal odour.
Nitrous acid converts it into ethylene oxide. Ethylene Dinitramine,
NO2NHCH2.CH,NHNOa (B. 22, R. 295)- Thionyl Ethylene Diamine, SO : N.CHa.-
CH2.N : SO, m.p. 5°, b.p.25 100° (B. 30, 1009).
Ethylene diamine and ojS-propylene diamine, like the orthodiamines of the
benzene series, combine with orthodiketones, e.g. phenanthraquinone and
benzil, to form pyrazine derivatives, similar in structure to the quinoxalines.
They also unite with the benzaldehydes and benzoketones (B. 20, 276 ; 21, 2358).
The action on ethylene diamine of CSCla (B. 27, 1663), and of aldehydes (C.
i899, I- 5941 B. 40, 881).
Dlacetyl Ethylene Diamine, m.p. 172°, consists of colourless needles. When
this compound is heated beyond its melting point, water splits off, and there
follows an inner condensation that leads to the formation of a cyclic amidine
base, closely allied to the glyoxalines. It is ethylene ethenyl amidine or methyl
glyoxalidine, which under the name Lysidine, m.p. 105°, b.p. 223°, has been
recommended as a solvent for uric acid (B. 28, 1176). The corresponding
propylene and trimethylene diamine derivatives react similarly (B. 36, 338) :
CH2NHCOCHS CHa.NHv
= | \CCH3+CH8COaH.
CHjNHCOCH8 CH2.N^^
Diacetyl Diethylene Ethylene Etheny
Diamine. Amidine.
CH..CH.NH
Propylene Diamine, | , b.p. 119-120° (B. 21, 2359), has been
CH2.NHa
resolved into optically active components by means of d-tartaric acid.
1-Propylene Diamine, [a]D= — I9'H°, forms a d-tartrate, which is sparingly
soluble (B. 28, 1180).
Trimethylene Diamine, CHt<£^a'^2, b.p. 135-136° (B. 17, 1799; 21,
2670), has been prepared by general methods i, 3, and 4 (from glutaric diazide),
and (2d) by reduction of i,3-dinitropropane (p. 155).
ay-Trimethyl Trimethylene Diamine p8-Diamino-p-methylpentane, (CH3)2C-
(NH2)CH2CH(NH2)CH8, is obtained from diacetone amino-oxime (p. 230) by
reduction with sodium amalgam (M. 23, 9) ; also by reduction of acetyl acetone
dioxime with sodium and alcohol. By the second method a labile a-diamino-
pentane, b.p.20 47°, is produced which is converted into the stable /J-diamino-
pentane, b.p.12 44°, by prolonged boiling with alkalis. Both bases yield cyclic
ethenyl amidines when heated with acetic acid (see above) (B. 32, 1191).
Tetramethylene Diamine, i.^-Diaminobutane, NH2[CH2]4NH2, m.p. 27°, is
obtained from ethylene cyanide by general methods 2 a and 26 from succin-
aldehyde dioxime (p. 355) (B. 22, 1970 ; 40, 3872). It is found during
cystinuria in the urine and fasces. With regard to its identity with putresce'ine
(which is produced during putrescence), see B. 40, 3875. Tetramethyl Tetra-
methylene Diamine, (CH3)2N.[CH2]4.N(CH8)2, b.p. 169°, occurs in Hyocyamus,
Henbane (B. 40, 3869).
i,4-Diaminopentane, CH8CH(NH2)CH2CH2CH2NH2, b.p. 172°, is formed
from the nitrile of pyroracemic acid according to method of formation 2 a.
2,5-Diaminohexane, CH3CH(NH2)CH2.CH2CH(NH2)CH$, b.p. 175°, is formed
from the diphenylhydrazone of acetonyl acetone (p. 356) according to
method of formation zc. It exists in two forms which are characterized by their
dibenzoyl derivatives : o-derivative, m.p. 238° ; /J-derivative, m.p. 183-185°.
334 ORGANIC CHEMISTRY
They bear a relation to each other similar to that shown by racemic acid
and mesotartaric acid (B. 28, 379).
i,4-Diamino-2-methyl P<mtew*,CHsCH(NH2)CH2.CH(CH,)CH2NH2, b.p. 175°,
is obtained from a-methyl laevulindialdoxime (p. 355) according to method of
formation zb (B. 23, 1790).
Pentamethylene Diamine, Cadaverine, i,5-Diaminopentane, NH2CH2.CH2.-
CH2.CH2CH2NH2, b.p. 178-179°, is obtained by the reduction of trimethylene
cyanide (method of formation 2a) (B. 18, 2956 ; 19, 780) ; also from penta-
methylene diphthalimide (by method of formation 5) (Preparation, see B. 37,
3583) ; and further, from lysine (i,5-diaminocaproic acid) (mode of formation
6, p. 332). It forms a hydrate containing 2H2O (B. 27, R. 580). It is identical
with cadaverine, a ptomaine isolated from decaying corpses (B. 20, 2216, and
R. 69).
Neuridine, C5H14N2 (B. 18, 86), formed by the decay of fish and meat, is
isomeric with pentamethylene diamine.
Hexamethylene Diamine, i,6-Diaminohexane, NH2[CH2]6NH2, m.p. 42°,
b.p.20 1 00°, is formed in the hydrolysis of Hexamethylene Diethyl Urethane,
[CH2]6(NHCO2C2H6)2, m.p. 84°, which results upon boiling the suberic acid
azide with alcohol (J. pr. Ch. [2] 62, 206). Also from i,6-diaminosuberic acid
by distillation (mode of formation 6, p. 332) ; further, by reduction and hydrolysis
of e-benzoylaminocaproic acid nitrile, CeH6CONH[CH2]BCN (B. 38, 2204).
Heptamethylene Diamine, NH2(CH2]7NH2, m.p. 29°, b.p. 224°, is prepared
from azelaic amide and KBrO, and from pimelic nitrile by reduction (B. 38,
2204).
i,8-Diamino-octane, CH2NH2[CH2]6CH2NH2, m.p. 51°, b.p. 226°, is obtained
from the amide or azide of sebacic acid (method of formation 3 or 4) (J. pr. Ch.
[2] 62, 227); and from i,8-diaminosebacic acid (method of formation 6,
p. 332). Its hydrochloride gives o-butyl pyrrolidine on heating (C. 1906, II. 527).
i,9-Diamino-nonane, m.p. 37°, b.p. 258°, is obtained from azelaic nitrile (q.v.)
(C. 1897, II. 849).
i,io-Dekamethylene Diamine, NH2CH2(CH2)8CH2.NH2, m.p. 61-5°, b.p.lt
140°, results from the nitrile of sebacic acid (method of formation 2a) (B. 25, 2253).
Cyclic Alkylene Imines.
Two classes of these substances are known — the alkylene monimines,
which contain one immo-group, and the dialkylene diimines, which
contain two alkylene residues and two imino-groups.
I. Alkylene Monimines.
To this group belong compounds corresponding with the alkylene oxides :
2v /CH2\ CHa— CH2V /CH2— CH.x
>NH CH2< >NH | >NH CH/ >NH
/ \CH/ CH2— CH/ N3H2— CH/
Dimethylene Imine Trimethylene Tetramethylene Pentamethylene
Ethylene Imine. Imine. Imine. Imine.
Methods of Formation. — (i) Upon heating the diamine hydrochlorides, when
ammonia splits off as ammonium chloride, e.g. :
ClH.NH2CHaCH2CH2CH2CH,NH2.HCl=CHaCH2CH2CH2CH2NH.HCl+NH4Cl.
Pentamethylene Diamine Hydrochloride. Pentamethylene Imide, Piperidine.
(2) By the splitting-off of halogen acid from the halogen alkyl amines —
e.g. when the hydrochloride is heated, or when it is digested with dilute potassium
hydroxide (B. 24, 3231 ; 25, 415) :
C1CH2CH2CH2CH2CH2NH2 = (!:H2CH2CH2CH2CH2NH.HC1.
e-Chloramylamine. Piperidine Hydrochloride.
(3) They are produced, together with the diamines, in the reduction of
alkylene dicyanides.
I
NITROGEN DERIVATIVES OF THE GLYCOLS 335
The tendency to form imino-rings and the stability of such rings towards
reagents producing cleavage, depends on the number of members taking part
in their structure, as has been seen to be the case among the ethylene oxides
(P- 31?)-
Whilst ethylene imine is easily decomposed (see below), the tetra- and penta-
methylene imines are very stable, and special methods are required to break
them open. Such are : (i) the iodomethylate method, which breaks the quaternary
ammonium iodides into olefine dialkyl amines by means of alkali ; (2) oxidation
of the benzoyl imines, which produces benzoyl amino-fatty acids ; (3) heating
-benzoyl amines with phosphoric halides, forming dihalogen paraffins and benzo-
nitrile (comp. p. 321). These methods will be discussed under Heterocyclic
Compounds (Vol. II.).
The investigation of the hexa-, hepta, and deca-methylene imines leaves it
rather doubtful as to whether these ring-systems can exist ; it appears, however,
that the hydrochloride of octomethylene diamine can be prepared by heating
decamethylene diamine, with the partial atomic rearrangement to form a-alkyl
pyrrolidine (see below) (comp. B. 39, 2193, 4110 ; C. 1906, II. 527).
CH2>.
Ethylene Imine, Dimethylene Imine, >NH, b.p. 55°, D20 =0-8321, is
CH
/
obtained from bromethylamine by means of Ag2O or potassium hydroxide solu-
tion. It is a water-clear liquid, which smells strongly of ammonia, dissolves in
water, and acts corrosively on the skin. It is stable against permanganate and
bromine, which shows that the above formula is correct rather than the earlier
vinyl formula which was assigned to it. With benzene sulphochloride (Vol. II.)
and alkali, it forms a sulphamide, insoluble in alkali. It combines with hydro-
bromic acid in the cold to form bromethylamine, with H2S to thiodiethylamine,
CH2V
and with sulphurous acid to taurine. n-Methyl F-thylene Imine, \ \NCHa,
b.p. 28°, is prepared from chlorethyl methylamine, C1CH2CH2NHCH3, and alkali.
Similarly to ethylene imine, it is converted by iodomethane into iodo-ethyl
trimethyl ammonium iodide, ICH2CH2N(CH3)2I (B. 34, 3544).
Trimethylene Imine, CH3<£**2>NH, b.p. 63°, D20=o-S436. If trimethylene
bromide and alkali react on ^-toluol sulphamide, p- toluol sulphotrimethylene
imide is produced ; and when this is hydrolyzed by sodium in amyl alcohol
solution, trimethylene imide is produced. It is easily decomposed by acids, as is
ethylene imine (B. 32, 2031).
CH2.CH2X
Tetramethylene Imine, Tetrahydropyrrole, Pyrrolidine, I /NH, b.p. 87°,
CH2.CH/
is obtained from tetramethylene diamine (method of formation i) ; from
8-chlorbutylamine and potassium hydroxide (method 2) (B. 24, 3231), and by
the reduction of pyrroline, the first reaction-product of pyrrole (B. 18, 2079),
and of succinimide (see Succinic Acid) (B. 32, 951) :
CH=CH\ 2H CH.CH2V 2H CH2.CH2V
>NH - > || >NH - > | >NH.
CH=CHX CH-CH/ CH2.CH/
Pyrrole. Pyrroline. Pyrrolidine, Tetramethylene
Imide.
Tetramethylene imide has an odour resembling that of piperidine. Tetra-
methylene Nitrosamine, C4H8NNO, b.p. 214° (B. 21, 290). n-Methyl Pyrrolidine,
(CH2)4NCH3, b.p. 82°, is produced by distillation of tetramethyl tetramethylene
diamine dichloromethylate (p. 333).
CH2.CH(CH3K
1- or a-M ethyl Pyrrolidine, \ ^^>NH, b.p. 79°, is obtained from
CH2.CH2-^"
y-valerolactam (q.v.).
2- or fi-Methyl Pyrrolidine, b.p. 103° (B. 20, 1654).
i, ^-Dimethyl Pyrrolidine, b.p. 107° (B. 22, 1859).
1.,4-Tetramethyl Pyrrolidine (C. 1905, II. 830).
336 ORGANIC CHEMISTRY
Pentamethylene Imine, Piperidine, Hexahydropyridinc,
b.p. 106°, is obtained according to methods I, 2 (B. 25, 415) and 3
(p. 334) ; also from pipeline (Vol. II.), and by the reduction of pyridine,
into which it passes when it is oxidized :
6H
H— CH. - - - > xCH2.CH2v
V 3° CH/ >NH.
CH=CH/ •< - \CH2.CH/
Pyridine. Piperidine.
Piperidine bears the same relation to pyridine that is sustained by
pyrrolidine to pyrrole. Therefore, tetramethylene imide and penta-
methylene imide link the pyrrole and pyridine groups to the simple
aliphatic substances, the diamines, and their parent bodies, the glycols.
The pyrrole and pyridine derivatives will be discussed later in
connection with the heterocyclic ring systems, together with allied
bodies, and pyrrolidine and piperidine will again be referred to.
II. Dialkylene Diimines.
This class embraces those compounds corresponding with diethylene oxide
(p. 316), diethylene disulphide (p. 324), and diethylene imido-oxide or morpholine
(P- 330).
Diethylene Diimine, Piperazine, HexaJiydropyrazine,
m.p. 104°, b.p. 145°, was first prepared by the action of ammonia
on ethylene chloride. It is produced by heating ethylenediamine
hydrochloride (B. 21, 758), and by the reduction of pyrazine,
N^CH— CH^N (B> 26» ?24)- Jt is technically made from diphenyl
diethylene diamine, the reaction-product of aniline and ethylene
bromide, when it is converted into the p-dinitroso-compound, and the
latter then broken down into p-dinitrosophenol and diethylene diamine :
Diethylene diamine, or piperazine, is a strong base, soluble in
water, which upon distillation with zinc dust, changes to pyrazine
(Vol. II.) (B. 26, R. 441). It is important that piperazine unites with
uric acid to form a salt even more readily soluble than the lithium salt.
Hence its strongly alkaline, dilute solution has been recommended
as a solvent for uric acid (B. 24, 241). For piperazine derivatives, see
B. 30, 1584.
Quaternary Piperazonium Halides are obtained by the action of iodo-alkyls
on piperazine (B. 36, 145) ; and also by spontaneous change of )3-chlor- or brom-
ethyl dialkylamines (p. 331) whereby the oily bases are converted into solid
neutral salts :
2C1CH2CH2N(CH,)2 - > C1N(CH3)2<^2-CH,>N(CH3)2C1
Chlorethyl Dimethylamine. Tetramethyl Piperazonium Dicbloride.
Alkali produces ethylene methylimine and the polymeric n-dimethyl piperazine,
whilst chlor- and brom-ethylamine yield only ethyleneimme.
ALDEHYDE-ALCOHOLS 337
Dipiperldyl Piperazonium Bromide,
obtained, analogously to the above, from jS-bromethyl piperidine, (CH2)5NCH2-
CHaBr. It is also prepared from piperazine and two molecules of dibromo-
pentane.
These quaternary piperazonium halides are decomposed by alkalis partly
into acetylene and tetra-alkyl ethylene diamines :
and partly into hydroxethyl dialkylamines.
Dry distillation decomposes tetramethyl piperazonium chloride into chloro-
methane and n-dimethyl piperazine (B. 37, 3507 ; 38, 3136 ; 40, 2936).
Trimethylene Ethylene Diimine,
prepared from trimethylene ethylene p-toluene sulphimide,
and HC1 (B. 32, 2041 ; 33, 761).
Bis-Trimethylene Diimine, NH<™a™a£**a>NH, m.p. 15*, b.p. 187°,
is obtained from its p-toluene sulphimide, which is the product of reaction
between trimethylene bromide and the di-sodium salt of di-p-toluene sulpho-
trimethylene diamide, CHsC,H4SO2NNa.CH,CHaCH8.NNaSO2C,H4CH, (B. 32,
2038).
The spontaneous change of y-chloropropyl dimethylamine, ClCHaCHaCHaN-
(CH,)2, produces Bis-trimethylene Tetramethyl Diimonium Chloride, C1(CH3)ZN-
[CHjCHjCHaltNtCHj^Cl (comp. above, piperazonium bromide; and B. 39,
1420).
a. ALDEHYDE-ALCOHOLS
These contain both an alcoholic hydroxyl group and the aldehyde group
CHO, hence their properties are both those of alcohols and aldehydes (p. 191).
The addition of 2 H-atoms changes them to glycols, whilst by oxidation they
yield the hydroxy acids, containing a like number of carbon atoms. The most
important representatives of this group are the j3-hydroxyaldehydes or aldols,
which result from the aldol condensation of the simple aldehydes.
Glycollic Aldehyde, [Ethanolal], CH,(OH)CHO, m.p. 95-98°, is the first
aldehyde of glycol, and can be obtained from it by oxidation with hydrogen
peroxide in the presence of ferrous salts. It is also prepared from bromacetalde-
hyde and barium hydroxide solution, and from chloracetal by treatment with
alkali followed by acid (C. 1903, I. 1427). Further, it is very easily produced
from dihydroxymaleic acid (an oxidation product of tartaric acid) by heating it
with water at 50-60°. A noteworthy formation, although only in small
quantities, is that by condensation of formaldehyde by means of CaCO8 (B. 39,
50). Glycollic aldehyde remains behind, when its solution evaporates, as a
slightly sweet syrup ; this can be distilled under reduced pressure, when it
solidifies ; on melting it undergoes condensation very easily. Bromine water
oxidizes it to glycollic acid (p. 362), whilst it is condensed by sodium hydroxide
solution to tetrose (q.v.), and by sodium carbonate solution to acrose (q.v.) (B.
25, 2552, 2984 ; C. 1899, II. 88 ; 1900, I. 285). Hydroxylamine gives rise to
an oily oxime (C. 1900, II. 312), and phenylhydrazine and acetic acid produce
glyoxal osazone (p. 356).
The following derivatives of glycol aldehyde have already been discussed :
CHO CH(OCaH,)a CHC1, CHC1,
I I I i
CH2Cl(Br,I), CH2Cl(Br) CH2OH CH2C1
Monochlor- (brom-, iodo-) Monochlor-(brom- Dichlorethyl 1,2-Trichlorethane
acetaldehyde (p. 203). acetal (p. 205). Alcohol (p. 117). (p. 95).
Glycol Acetal, CHaOH.CH(O.C8H,)a, b.p. 167°, is obtained from bromacetal
(B. 5, 10).
VOL. I. Z
338 ORGANIC CHEMISTRY
Glycol Dimethyl Acetal, CH2OH.CH(OCH3)2, b.p. 158°, is produced from
glycol aldehyde by hydrochloric acid in methyl alcoholic solution (B. 39, 3053).
Ethoxyacetal, C2H5O.CHaCH(OC2H,)2, b.p. 168°, is prepared from i,2-dichlor-
ether (p. 129), or from chlor- or brom-acetal and sodium alcoholate. Greatly
diluted sulphuric acid or a molecular proportion of water in acetone solution
produces Ethoxy acetaldehyde, C2H,O.CH2CHO, b.p. 71-73° (B. 39, 2644;
C. 1905, I. 1219; 1907, I. 706). Phenoxyacetal, C.H.O.CHj.CH^CjH,)^
b p. 257° (B. 28, R. 295).
a-Hydroxypropionaldehyde, CH,CH(OH)CHO, is unknown. a-Acetoxypro-
pionaldehyd(
acetate
formed^ __ _ . - .
potassium formate and methyl alcohol, instead of the expected o-hydroxypro-
pionaldehyde (A. 335, 266). Dichlorisopropyl Alcohol, C12CHCH(OH)CH8, b.p.
147°, can be looked on as a derivative of a-hydroxypropionaldehyde. It is
prepared from dichloraldehyde and CH3MgBr (B. 40, 27).
a-Hydroxybutyl Aldehyde, (CH3)aC(OH).CHO, b.p. 137°, is prepared from
a-Bromoisobutyl Aldehyde, b.p. 113°, and water. It is an easily polymerizable
liquid. Sodium hydroxide solution converts it into isobutylene glycol (p. 313) and
a-hydroxybutyric acid, a reaction which other aldehydes undergo (M. 21, 1122).
fi-Hydroxypropionaldehyde, Hydracrylic Aldehyde, HOCH2.CH2CHO, b.p.18
90°, is produced when acrolein is heated with water to 100° : semicarbazone,
m.p. 114°, regenerates acrolein when treated with bisulphate. It easily poly-
merizes. Alkali partially converts it to crotonaldehyde (A. 335, 219). fi-
Hydroxypropionacetal, OHCH2.CH2.CH(OC2H5)2, b.p.to 98°, is prepared by
prolonged boiling of dilute sodium hydroxide solution at 115° with fi-Chloro-
propionacetal, b.p.20 74°, the addition product of acrolein acetal (p. 213) and
HC1 (B. 33, 2760). Isotnethylin, CH3CH(OC2H5)CH(OC2H6)2, or possibly
CH2(OC2H5).CH(OC2H6)2, b.p.]t 81°, results when acrolein and alcohol are
heated together at 50° for several days ; and also by the action of orthoformic
ether on acrolein (B. 31, 1014).
Aldol, p-Hydroxybutyraldehyde, CH3.CH(OH).CH2.CHO, b.p.12
60-70°, D0=ri2o, was discovered by Wurtz in 1872. It is obtained
by the condensation of acetaldehyde by means of dilute cold hydro-
chloric acid, and other condensation agents, e.g. K2CO3 (B. 14, 2069 ;
24, R. 89 ; 25, R. 732 ; M. 22, 59 ; C. 1907, 1. 1400).
Aldol freshly prepared is a colourless, odourless liquid, and is
miscible with water. It distils under atmospheric pressure, partially
reforming acetaldehyde, but it mainly becomes converted into croton-
aldehyde and water.
As an aldehyde it will reduce an ammoniacal silver nitrate solution.
Heated with silver oxide and water it yields fi-hydroxybutyric acid,
CH3.CH(OH).CH2.C02H.
After prolonged standing aldol polymerizes, becoming viscous, sometimes
depositing crystals of Paraldol, (C4H,O2)2, m.p. 80-90° (M. 21, 80). If, during
the preparation of aldol, the mixture of aldehyde and hydrochloric acid be left
undisturbed, the aldol condenses with loss of water to Dialdan, C,H14OS, m.p.
139°, a crystalline body which reduces ammoniacal silver solution. Tetraldan,
CieH2,O6, is formed simultaneous with dialdan, and does not reduce silver from
its ammoniacal solution (C. 1900, II. 838). Diethyl Acetal of fi-Ethoxybutyric
Aldehyde, CH3.CH(OC2H8)CH2.CH(OC2H5)2, b.p.14 73° (B. 31, 1014).
The aldol condensation is characteristic for this class of substance and occurs
among the higher members of the series when a free hydrogen atom exists next to
the aldehyde group. Thus, a series of j8-hydroxyaldehydes or aldols can be
prepared. A mixture of two aldehydes yields mixed aldols. The condensing
agent mostly employed is potassium carbonate :
2CH3.CH2CHO = CH3CH2CH(OH)CH(CH3)CHO
CHaO + (CH3)2CHCHO = CH2(OH)C(CH,)aCHO.
NITROGEN-CONTAINING DERIVATIVES 339
Like aldol itself, the homologous aldols are easily converted into a,j3-olefine
aldehydes when a hydrogen atom in the a-position is free, and are stable bodies.
If, however, there is no a-hydrogen atom present, some members decompose
more easily than aldol into the simple aldehyde. Aldols from isobutyric aldehyde
are further acted on by hot alkali during reaction and are transformed into the
corresponding glycols and isobutyric acid (p. 308) (Lieben, M. 22, 289).
Formisobutyric Aldol, CH2(OH).C(CH3)2.CHO, m.p. 90°, b.p.15 85°, is converted
into /J-dimethyl trimethylene glycol (p. 314) and a-dimethyl /3-hydroxypropionic
acid by the action of alkalis. Acetopropionic Aldol, CH8.CH(OH).CH(CH3)CHO,
b.p.2092°. Propionic Aldol, b.p.,3 95°. Isobutyric Aldol, b.p.17 IO4°-IO9°. Iso-
butyric Isovaleric Aldol is decomposed by heat into its component parts. For
other aldols, see C. 1904, I. 199 ; II. 1599 ; vapour pressure of the aldols, see
M. 21, 80.
NITROGEN-CONTAINING DERIVATIVES OF THE ALDEHYDE-ALCOHOLS
Nitroaldehydes.
Nitroacetaldehyde, NO2CH2CHO, has not yet been isolated. Methazonic Acid,
formulated otherwise on p. 151, can probably be looked on as being its oxime.
It is prepared from two molecules of aci-nitromethane by a kind of aldol con-
densation (see formation of glycol aldehyde from formaldehyde, p. 337) accom-
panied by loss of water :
HOaN:CH2 +CH2:N02H > [HO2N:CH.CH2.NO2H] > HO2N:CH.CHNOH :
aci-Nitrome thane. Intermediate product. . Methazonic Acid.
Phenylhydrazine and aniline yield respectively the Hydrazone, NO2CH.-
CH:N:NHC6H5, m.p. 74°, and the Anilide, NOaCH,CH:NC.H6, m.p. 95° (B.
40, 3435).
It is justifiable, on systematic grounds, to include in this section the aldol-
like condensation products of aldehydes with potassium dinitromethane (p. 154) :
CHaO+CH(N02):NOOH±^:CH2(OH).C(N02):N02H.
aci-Dinitrome thane. aci-Dinitro-etbyl Alcohol.
The resulting potassium salts form yellow crystals, which, as such or in aqueous
solution, decompose into their components on being heated. The free acids are
strongly acid, easily decomposable oils. Similar condensation products, e.g.
a-Dinitro-alkylamines, are also obtained from the aldehyde-ammonias or amino-
compounds and dinitromethane :
CH3CH(NH2)OH+CH2(NO2)8 >• CH3.CH(NH2)CH(NOa),
a-Dinitro-/3-aminopropane.
(CH3)2NCH2OH+CH2(NOa)a >- (CH3)2N.CH2.CH(NO2)2.
a-Dinitro"-/3-dimethyl Aminoethanc.
These bodies are more stable, probably on account of their forming cyclic
internal salts (comp. p. 327) between the acid nitro- and the amino-groups
(B. 38, 2031, 2040). Finally, formaldehyde and acetaldehyde unite with
nitrobromomethane (p. 429) to form, respectively, a-Nitrobromethyl Alcohol,
NO2.CHBr.CH2OH, b.p.45 147°, and a-Nitro-bromisopropyl Alcohol, NO2CHBr.-
CH(OH)CH3, b.p.4a 149° (C. 1899, I. 179).
Aldehyde-Ammonias. — Ammonia gas converts aldol in ethereal solution into
aldol-ammonia, C4H8O2.NH3, a thick syrup, soluble in water. When heated
with ammonia the bases, C,H16NO2, C8H13NO, oxytetraldine (p. 215), and
collidine, C5H2N(CH3)3, are formed. With aniline aldol forms methyl quinoline.
(Comp. alkylidene anilines.)
Amidoaldehydes : Aminoacetaldehyde, [Ethanalamine], [2-Amino-ethanal],
NH2.CH2CHO, is obtained as a deliquescent hydrochloride when aminoacetal,
NH2.CH2(OC2H5)a, b.p. 163°, is treated with cold, concentrated hydrochloric
acid. Aminoacetal is produced when chloracetal is treated with ammonia
(B. 25, 2355 ; 27, 3093). Aminoacetaldehyde is also obtained from alkylamine
by the splitting action of ozone (comp. p. 84, etc.) (B. 37, 612) :
CHa:CH.CHaNHt — ^-> CPI,O-j-OCH.CHa.NH§.
34o ORGANIC CHEMISTRY
f*TT /"*TT
Aminoacetaldehyde yields pyrazine, NCCH~CH^N (B. 26, 1830, 2207), when
it is oxidized with mercuric chloride. On Dialkyl aminoacetals and the Dialkyl
aminoacetaldehydes and trialkyl ammonium salts, see B. 30, 1504.
Hydrazine Acetaldehyde (B. 27, 2203).
Brtaftt* Aldehyde, (CHS)8'N.CH2CHO(OH) (?) (B. 27, 165), is different from
Muscarine (p. 329), which occurs in fly agaric (Agaricus muscarius).
Isomuscarine, HO.CH2CH(OH)N(CH3)3OH (?), is obtained from the addition
product of HC1O and neurine (p. 329) with silver oxide (A. 267, 532, 291).
a-Aminopropionaldehyde, CH3CH(NHa)CHO, is obtained by the action of
ozone on a-styryl ethylamine (B. 37, 615).
B-Atninopropionaldehyde, NH2CH2.CH2.CHO, is obtained as a salt by the
breaking down of its acetal, NH2CHa.CH2CH(OC2H,)2, b.p.lt 80°, which, in
turn, is produced from /?-chloropropionic acetal (p. 338), by digestion with
alcoholic ammonia. At the same time there is formed Iminodipropionic Acetal,
HN[CH2CH2CH(OC2H6)2]2, b.p.16 157°, which on hydrolysis yields iminodi-
propionic aldehyde, a substance which undergoes ring-condensation to form
p-Tetrahydropyridine Aldehyde (B. 38, 4162) :
NH.CHa.CH2.CHO NH.CHa.C.CHO
I > I II
CHa.CH2CHO CHa.CH2.CH
y-Aminobutyric Acetal, NH2.CH2CH2.CHaCH(OC2H5)s, b.p. 196°, results
from the reduction of j9-cyanopropionic acetal by sodium and alcohol. Its
Benzene sulpho derivatives condense spontaneously forming n-Benzene sulpho-a-
ethoxypyrrolidine, which is reduced to Pyrrolidine by sodium and amyl alcohol
(B. 38, 4157) :
C.H6.S02.NH.CH2, CtH5S02N.CH2v
yCHj ^ / yCHj
(CaH60)aCH.CH/ CaH6O.CH.CH/
HN.CHjv
> I >CHr
HjC.CH/
&-Aminovaleric Aldehyde, NH2CH2CHaCH2CH2CHO, and its homologues
were thought to have been produced by the oxidation of piperidine (p. 336
and Vol. II.) with H2Oa ; but this is now known to be Piperidine Oxide,
3. KETONE-ALCOHOLS OR KETOLS
The ketone alcohols or ketols are distinguished, according to the
position of the alcohol or ketone groups, as a- or 1,2-, j8- or 1,3-, y- or
1,4-ketolSi etc. The position of these two groups, with reference to
each other, influences the chemical character of these bodies more
than the type of alcohol group (whether primary, secondary, or
tertiary). These alcohols show simultaneously the character of
alcohols and of ketones.
A. SATURATED KETOLS
o- or i,2-Ketols show tendencies to desmotropic transformations. Many of
their modes of formation and reactions point to the isomeric forms of the Olefine
glycols (p. 315) or Hydroxyethylene oxides. Acetal (p. 341) undergoes certain
easily followed changes which permit of a decision being made as to which of
the following four formulae are to be assigned to it : —
CH8CO.CHaOH CH,C(OH).CHab CH,C(OH):C(OH)H CH8CH(OH)CHO.
SATURATED KETOLS 341
The di-acylates of the olefine glycols (p. 315) yield ketone-alcohols on
hydrolysis, and some of the sodium compounds of these reproduce olefine glycol
diacylates by reaction with acyl chlorides.
Phenylhydrazine and the a-ketone aldehydes yield, by oxidation, osazones
of i,2-aldehyde ketones or i,2-diketones (comp. the Dextroses).
Acetyl Carbinol, Pyroracemic Alcohol, Acetone Alcohol, Acetol, Hydroxy acetone,
[Propanolone], CH3COCH2OH, b.p. 145-146°, b.p.18 54°, is obtained :
(1 ) From chlor- or bromacetone ; or best by heating potassium formate
and methyl alcohol, when the first formed acetyl formate is alcoholyzed by the
methyl alcohol.
(2) A remarkable mode of formation is from a-bromopropionic aldehyde or
a-acetoxypropionic aldehyde (see pp. 338, 340) (A. 335, 247).
(3) From propylene glycol and the Sorbose bacterium, or by careful oxidation
with bromine water (C. 1899, II. 475 ; 1900, I. 280).
(4) If glycerol vapour is passed over pumice-stone at 430-450° some acetol
is formed.
(5) When sucrose or dextrose is fused with potassium hydroxide, acetol
results (B. 16, 834).
Acetol reacts acid (comp. formula, p. 340) (C. 1905, II. 29). Reduction with
aluminium amalgam yields propylene glycol (p. 313) and acetone (C. 1903, I.
132). Acetol shows a strong reducing action, and when oxidized by the oxides of
Cu. Hg, Fe is converted into lactic acid, with the probable intermediate formation
ot pyroracemic aldehyde :
O H20
CHSCO.CH2OH > [CH3CO.CHO] > CH3CH(OH)COOH.
Permanganate, chromic acid, and the like, oxidize acetol into acetic and
formic acids (C. 1905, I. 19).
Methyl alcohol containing a trace of hydrochloric or acetic acid converts
acetol into Bis-acetol Methyl Alcholate, CHIQ>C<O— CI?^0^?^3' m'p' I3°°'
b.p. 196°. Acetol Ether Ether, CH3COCH2.O.C2H5, b.p2 128°, is prepared from
propargyl ethyl ether (p. 129), or synthetically, from ethoxyacetonitrile,
C2H6OCH2CN and methyl magnesium iodide. Similar homologous ethoxymethyl
alkyl ketones (C. 1907, I. 872) may be obtained. On the formation of such
ketones from halogen acetoacetic esters, see B. 21, 2648. Acetol Formate,
HCOO.CH2COCH3, b.p. 169°, and higher esters, see C. 1905, II. 754. Chlor-,
Brom-, lodo-acetone (p. 224) are the haloid esters of acetyl carbinol.
Propionyl Carbinol, Ethyl Ketol, CH3CH2CO.CH2OH, b.p. 160°, is obtained
from chloromethyl ethyl ketone, C1CH2COCH2CH3 ; also from tetrinic acid
(q.v.) by the loss of CO2 on boiling with water. It is oxidized by Fehling's solu-
tion to a-hydroxybutyric acid (C. 1905, II. 116).
The secondary a-ketone alcohols are obtained by the two following general
methods : —
(1) The esters of the fatty acids in ethereal or benzene solution and in the
presence of sodium yield acylo'ins (comp. Benzoin, Vol. II.) through the union
of the two acyl radicals (C. 1906, II. 1113) :
2R.COOC2H5+4Na — > 2NaOC2H6 + [R.C(ONa):C(ONa)R] — > RCO.CH(OH)R.
(2) Acylates, produced by the action of sodium on the acid chlorides of the
olefine glycols (p. 315) yield acyloins on hydrolysis :
H80
4RCOC1 +4Na >• 2NaCl + RC(OR):C(OR).R > R.COCH(OH)R.
Acetyl Methyl Carbinol, Dimethyl Ketol, Aceto'in, [2,3-Butanonal], CH3CH-
(OH)COCH3, b.p. 148°, is produced in small quantities from acetic ester in
ethereal benzene solution by means of sodium. Also, from methyl chlorethyl
ketone, CH3COCHC1CH3 ; from j3y-butylene glycol (p. 313) by the action of
the Sorbose bacterium or Mycoderma aceti ; and from various carbohydrates by
the Bacillus tartricus (C. 1901, I. 878; 1905, II. 117; 1906, II. 1113). It is
prepared from diacetyl (p. 349) by reduction with zinc and sulphuric acid (B.
40, 4338). Acetyl Ethyl Carbinol, CH3CO.CH(OH)C2H6, b.p.38 77°, is similarly
obtained from acetyl propionyl (B. 23, 2425). The sodium compound of dimethyl
ketol (acetoin) (obtained from acetic ester) when treated with acetyl chloride.
342 ORGANIC CHEMISTRY
yields the Diacetate of the Olefine Glycol, CH3C(OCOCH3):C(OCOCH8)CH8,
bp.2B 110-115° (C. 1906, II. 1113). Dimethyl Ketol polymerizes spontaneously
to a dimer (C4H8O2)2, m.p. 95° (B. 40, 4336).
According to the above methods, i and 2, the following compounds can also
be prepared : Propionoin, C2H5COCH(OH)C2H5, b.p.20 73°. Butyrom, b.p.10 85°.
Isobutyroin, b.p.28 83°. Valeroin, b.p.]2 156°. Pivalom, (CH3)3CCO.CH(OH)-
C(CH3)3, m.p. 81°, b.p.to 80°. Capronoin, b.p.8 131°. These keto-alcohols are
reduced 'by sodium and alcohol partially to the glycols and partially to secondary
alcohols. Heated with finely divided copper they yield a-diketones ; con-
centrated potassium hydroxide solution with atmospheric oxygen converts
them partially to tertiary alcohol acids (comp. the Benzylic acid transformation,
Vol. II.) (C. 1906, II. 1114 ; B. 31, 1217).
B- or i,3-Ketols.
When the aldol condensation (p. 338) is carried out with aldehyde or chloral
and acetone, methyl ethyl ketone and methyl isopropyl ketone by means of
potassium cyanide, the following compounds result (B. 25, 3155; C.
1897 I.ioiS; 1905, 11.752): Hydracetal Acetone, S-Hydroxy-fi-Ketopentane,
CH8CH(OH)COCH8, b.p. 176°. Chloral Acetone, CC13CH(OH)CH2COCH3,
m.p. 75°. Hydracetyl Ethyl Methyl Ketone, Methyl-3-pentane-2-on-4-ol, CH3-
CH(OH)CH(CH3)COCH3, b.p. 187°. Hydracetyl Isopropyl Methyl Ketone, Di-
methyl-3-pentane-on-2-ol-4, CH3CH(OH)C(CH3)2COCH3, b.p.10 80°, gives on
oxidation meso-dimethyl acetyl acetone (p. 351).
Diacetone Alcohol, (CH3)ijC(OH)CH2COCH3, b.p. 164°, is obtained from
diacetonamine (p. 230) and nitrous acid ; also when two molecules of acetone
are condensed by concentrated sodium hydroxide solution at o°. Heat reverses
this reaction and the alkali breaks up the compound into acetone (Z. phys. Ch.,
33, 1129 ; C. 1902, II. 1096). Loss of water changes these /3- or i,3-ketols into
unsaturated ketones (p. 228) ; e.g. diacetone alcohol is converted into mesityl
oxide. Mesityl Oxide Sesquimercaptol, (CH3)2C(SC2H5)CH2.C(SC2H6)2CH3, can
be looked on as being a derivative of diacetone alcohol. It is prepared from
mesityl oxide, mercaptan, and HC1, and is an oil. Oxidation changes it into
Trisulphone, (CH3)2C(SO2C2H5).CH2.C(SO2C2H5)2CHS, m.p. 100° (B. 34, 1398).
A series of further derivatives of diacetone alcohol, such as Diacetone Hydroxyl-
amine, fi-Nitroso- and j$-Nitro-isopropyl Acetone have been dealt with (p. 231)
in connection with mesityl oxide.
The haloid esters of the fi-ketoles are the j8 -halogen ketones (p. 225), of
which mention may here be made of fi-Chlorethyl Ethyl Ketone, b.p.to 68°, £-
Chlorethyl Isopropyl Ketone, b.p.10 73°; and fi-Chlorethyl Isobutyl Ketone, b.p.ia
80°, having the general formula C1CH2CH2COR, which are prepared from
j8-chloropropionyl chloride and zinc alkyls.
y- or i,4-Ketols and 8- or i,5~Ketols.
Representatives of these are obtained from the products of reaction of
ethylene bromide and trimethylene bromide on sodium acetoacetic ester, by
boiling with hydrochloric acid (B. 19, 2844 ; 21, 2647 ; 22, 1196, R. 572) :
C02C2HB 2H20 C02+C2H6OH
CH3.CO.CH.CH2CH2Br CH3CO.CH2CH2CH2OH+HBr
Bromethyl Acetoacetic Ester. Acetopropyl Alcohol.
C02C2H6 2H20 C02+C2H8OH
CH3.CO.CH.CH2CH2CH2Br CH3CO.CH2CH2CH2CH2OH -j-HBr.
Brompropyl Acetoacetic Ester. Acetobutyl Alcohol.
(1) y-Acetopropyl Alcohol, CH8.CO.CH2CH2CH2OH, b.p. 208°, with decom-
position (C. 1903, II. 551).
(2) 8-Acetobutyl Alcohol, CH8.CO.CH2CH2CH2CH2OH, decomposes about
155°.
These compounds when heated give off water and become converted into
the oxides of unsaturated glycols (below). Both ketone alcohols fail to reduce
an ammoniacal copper solution, but when oxidized with chromic acid yield the
corresponding carboxylic acids : Icevulinic acid (q.v.) and y-acetobutyric acid (q.v.).
They yield the correspo dins: glycols, y-pentamethylene glycol and B-hexamethylene
glycol, when reduced, y Methyl y-acetobutyl alcohol (B. 32, 61). Hydrobromic acid
converts ther
HYDROXYMETHYLENE KETONES 343
iverts them into bromopropyl methyl ketone, CH3.CO.CH2CH2CH2Br, and
bromobutyl methyl ketone, CH3.CO.CH2CH2CH2CH2Br, b.p. 216°. These bromides
are converted by ammonia into ring-shaped imides (B. 25, 2190), similar to the
y-diketories (p. 351). This reaction links the open, aliphatic compounds with
the pyrrole and pyridine derivatives :
CH2.CH3 _ CH2CH2OH _ CH2.CH2Br NH8 CH2.CHa
CH:C(CH3r CH2.CO.CH3 CH2.CO.CH3 tH:C(CH3r
Methyl Dihydrofurfurane. Methyl-Dihydropyrrole.
CH,.CH2.CH2 _ CH2.CH2.CH2OH _ CH.CH2.CH2BrNH3
dH:C(CH3)X) iH2.CO.CH, £H2.CO.CH8
Methyl Dihydropyrane. Tetrahydropicoline.
B. OleQne Ketols.
Methoxymesityl Oxide, (CH3)2C:C(OCH3)COCH8, b.p. 168°, and Acetoxy-
mesityl Oxide, (CH3)2C:C(OCOCH3).COCH8, b.p.12 74°, are derived from an
olefine a-ketol, and are prepared from bromomesityl oxide. Hydrolysis produces
acetoxymesityl oxide and acetyl isobutyryl respectively (p. 349) (B. 33, 500).
HYDROXYMETHYLENE KETONES
Compounds of this class are obtained from the ketones R.CO.CH8 and
R.CO.CH2R' and formic ester in the presence of sodium ethoxide, accompanied
by the loss of alcohol :
nr TT« C2HsONa
HC<™- L*+CH3COCH3— -^CH8COCH=CHONa+C2H6OH.
These substances were at first thought to be /J-keto-aldehydes. However, their
pronounced acid character has shown that they should be regarded as hydroxy-
methylene ketones, acyl vinyl alcohols (Claisen, B. 20, 2191 ; 21, R. 915 ; 22,
533. 3273 » 25, 178). According to the later nomenclature these compounds
can be described as aci-aldehyde ketones or aci-formyl ketones (comp. p. 40).
They dissolve in alkali carbonate solutions forming stable salts, and give green
coloured precipitates with copper acetate (B. 22, 1018). Acetic anhydride and
benzoyl chloride converts them in a free state as readily as the phenols into
neutral acetates and benzoates, insoluble in alkalis. Their alkali derivatives
and ethyl iodide yield ethoxymethylene ketone, which is saponified by alcoholic
alkalis, like the ethers of organic carboxylic acids. These compounds, — CO.CH
=CH.OH, are the first exceptions to the rule of Erlenmeyer (p. 37), according
to which the complex >C=CHOH present in open chains must invariably
become rearranged into the aldehyde form ]>CH.CHO. It is shown, on the con-
trary, that when a hydrogen atom of the methyl or methylene group in acetalde-
hyde or its homologues, R.CH2.CHO, is replaced by an acid radical, a rearrange-
ment of the aldehyde form into the vinyl alcohol form is sure to follow (B. 25,
1781).
In conjunction with this explanation it may be mentioned that the alkoxy-
methylene group — e.g. C2H6O.CH= — may be introduced by means of ortho-
formic ester and acetic anhydride into compounds which contain the atomic
grouping, — CO.CH2.CO — (B. 26, 2729), e.g. into acetyl acetone, acetoacetic
ester and malonic ester. The compounds which result will be described sub-
sequently in their proper places.
Hydroxymethylene Acetone, aci-Formyl Acetone, &ci- Acetoacetic Aldehyde,
CH3CO.CH=CHOH, b.p. about 100°, readily condenses in solution to [1.3.5]-
Triacetyl Benzene, C8H3[i.3.5-](CO.CH8)3 (q.v.). Hydrazine converts it into
3-methyl pyrazole, and phenylhydrazine into i-phenyl 3-methyl pyrazole
Hy -
i66<
aci-
valeryl Acetaldehyde, (CH3)2CH.CH2COCH : CHOH, b.p.1? 52°. aci-Isocaproyl
Acetaldehyde, C6HnCOCH : CHOH, cannot be distilled without decomposition
even in vacua (C. 1905, II. 393).
344 ORGANIC CHEMISTRY
NITROGEN-CONTAINING DERIVATIVES OF THE KETONE-ALCOHOLS
As in the case of the simple ketones, the ketone-alcohols can frequently be
characterized through their semicarbazones, oximes, and phenylhydrazones (comp.
pp 227 228) It has, however, already been pointed out that the a-ketols,
combining with phenylhydrazine, easily yield the osazones of the a-diketones.
The jS-hydroxymethylene ketones react with hydroxylamme and hydrazme, as
do the jS-diketones (p. 350); forming the cyclic compounds isoxazoles and
Those derivatives of the ketone-alcohols, in which the alcoholic group has
been replaced by a nitrogen group, have been most conveniently collected into the
following series of compounds.
lA. NITRO-KETONES
Nitroacetone, CH8COCH2.NO2, b.p. 152°, is prepared by oxidation of
nitroisopropyl alcohol (B. 32, 865). An apparently isomeric nitroacetone, m.p.
49°, is obtained from iodo-acetone and silver nitrate (B. 32, 3179) ; both substances
are acid in character. Aniline reacts with nitroacetone (m.p. 49°) forming
Nitroacetone Anil, CH3C(NC6H, CH2NO2, m.p. 87°, which can also be obtained
from nitrilomesityl dioxime peroxide (p. 231) and aniline acetate (A. 319, 230).
On nitroisopropyl acetone, see p. 231.
iB. Mesohalogen Nitro-alcohols, see p. 151.
2,2-Chloronitropropanol, CH8CCl(NO2)CHaOH, m.p. 13°, b.p.44 115°, is
prepared from i,i-chloronitroethane and formaldehyde. 2,2-Bromonitropro-
panol, CH3.CBr(NOt)CHaOH, m.p. 42°. 2,2-Chloronitrobutanol, CH3CH2CC1-
(NO2)CH2OH, b.p. 145-150° (C. 1897, II. 338 ; 1898 I. 194). Trinitrotrimethyl
Propane, (CH8)2C(NO2)C(NO2)2CH2CH3, m.p. 95°. is obtained from trimethyl
propane and nitric acid (B. 32, 1443).
(2 A.) Aminoketones of the saturated series are produced from the chlori-
nated ketones by the action of ammonia or amines, from the olefine ketones by
addition of ammonia and amines (mainly fi-aminoketones), and from the iso-
nitrosoketones by reduction with zinc chloride (a-aminoketones) (B. 30, 1515 ;
32, 1095).
Amino acetone, CH3COCH2NHa, is formed by the reduction of isonitroso
acetone and of nitroacetone (m.p. 49°). Further, by the breaking up of phthal-
imidoacetone (prepared from potassium phthalimide and chloracetone), a salt of
aminoacetone is obtained from which alkali liberates, not the simple base, but one
of the formula C,H10N8, accompanied by the elimination of water. By boiling with
water, the substance is converted into aminoacetone hydrochloride (B. 38, 752).
Aminomethyl Ethyl Ketone, NHj.CH2COCH2CH8, is obtained from its
phthalyl derivative (B. 37, 2474). Aminopropyl Methyl Ketone, CH3COCH-
(NH2)C2H6, is an oil which solidifies to a crystalline mass. Aminomethyl Iso-
propyl Ketone, (CH8)2CHCOCH2NHS (B. 32, 1201). By oxidation with mercuric
chloride, for instance, these compounds yield a pyrazine derivative, e.g. amino-
acetone is converted to Dimethyl Pyrazine NN (B. 27, R. 928).
\Crl = C (Cri 8 ) /
The pyrazines, ketines, or aldines are described among the heterocyclic compounds
in Vol. II. The hydrochlorides of the a-aminoketones easily react with potassium
cyanate forming imidazoles (Vol. II.), whilst potassium thiocyanate forms
imidazolyl mercaptans (Vol. II.) (B. 27, 1042, 2036).
Aminosulphonal, Aminoacetone Diethyl Sulphone, CH8C(SO2C2H6)2CH2NH,,
m.p. 94°, results from the action of hydrochloric acid on phthalimidosulphonal,
the oxidation product of phthalimidoacetone ethyl mercaptol. This, in turn, is
prepared from acetonyl phthalimide ethyl mercaptan and hydrochloric acid
(B. 32, 2749).
Dialkyl Aminoketones are produced to a considerable extent from chlor-
acetone and secondary amines. Dimethyl Aminoacetone, (CH3)2N.CH2COCH8,
b.p. 123°. Diethyl Aminoacetone, b.p. 153° (B. 29, 866). Trimethyl Acetonyl
Ammonium Chloride, Coprin, (CH,)8N(CH2COCH3)C1, is produced from mono-
chloracetone and trimethylamine. Its physiological action is similar to that of
curare (C. 1898, II. 631).
NITRO-KETONES 345
2B. Oleflne j3-Aminoketones are prepared from acetyl acetone (p. 350)
by the action of ammonia, primary and secondary alkylamines (B. 26, R. 295).
Acetyl Acelonamine, CH3CO.CH=C(NH2)CHS, m.p. 43°, b.p. 209°. Acetyl
Acetone Ethylamine, CH3CO.CH=C(NHC2H6)CH3, b.p. 210-215°. Acetyl Acetone
Diethylamine, CH3CO.CH=C[N(C2H6)2].CH3, b.p.24 155°.
3. Hydroxylaminoketones, see Diacetone Hydroxylamine (p. 231).
4. a-Halogen Ketoximes are formed by the action of hydroxylamine on
monohalogen acetone (p. 224). Chloracetoxime, CH2C1.C : N(OH).CH3, b.p. 71°.
Bromacetoxime, m.p. 36°. lodo-acetoxime, m.p. 64° (B. 29, 1550).
5. Ketoxime Amines.
Triacetonylamine Trioxime, N(CHa.C : N.OH.CH8)8, m.p. 184°, is prepared
from chloracetoxime and ammonia (B. 31, 2396).
6. Nitrosoketones, see Nitrosoisopropyl Acetone (p. 231).
7. Alkylene Nitrosoehlorides are prepared by the inter-action of amyl nitrite
and hydrochloric acid (comp. p. 327) ; Alkylene Nitrosites from amyl nitrite
and nitric acid ; Alkylene Nitrosates from nitrogen trioxide and dioxide and
alkylenes of the type R2C : CHR. They are nitrogen derivatives of the
a-ketoles (A. 241, 288 ; 248, 161 ; B. 20, R. 638 ; 21, R. 622 ; C. 1899, II. 176).
£-Isoamylene (Trimethyl Ethylene) is primarily converted by N,OS into a true
nitroso- compound (comp. 152), a liquid showing the characteristic blue colour.
On standing it polymerizes spontaneously to a white crystalline substance, m.p.
76°, which is depolymerized on melting. Alkalis partially convert the nitrosite
into the isomeric isonitroso- compound, m.p. 126°, with some decomposition •
(CH.)2C N2o3 (CH3)2CONO
II > I
CH3CH
iso- compound, m.p. 126°, with some decomposition :
(CH3)2CONO > (CH3)aC.ONO
->. < > BistrimethyI->
CH8CHNO Ethylene Nitrosite. CH8.C:NOH
ethylene and N2O4 yield a nitrosate, (CH8).C(ONO
Similarly, trimethyl ethylene and N2O4 yield a nitrosate,
CH(NO)CH8, a blue liquid, spontaneously polymerizing to Bis-trimethyl Ethylene
Nitrosate, m.p. 99°, consisting of white crystals, which on being warmed in
solution become both de-polymerized and converted into the isomeric isonitroso
compound (B. 35, 2323). Treatment with amines causes a replacement of the
O.NO2 group for NHR, whereby the nitrolamines are formed, which pass into
keto-amines :
(CH8)2CO.NOa C,H6NHa (CH8)2C.NHC,H6 H2O CH8.C.NHC,Hf
CH8CHNO CH3CHNO CH8 CO.
The — ONO2 group of the amylene nitrosate can be exchanged for CN by the
action of potassium cyanide, the resulting nitrile being convertible into the
oxime, m.p. 97°. This body decomposes into CO2 and methyl isopropyl ketoxime,
whereby its constitution is indicated :
(CH,)2CONOa (CH3)2C.CN (CH3)2C.CO2H (CH8),CH
CH3CNOH CH3CNOH CH8.CNOH CH9CNOH
0-Isoamylene Isoamylene Ketoxime Methyl
Nitrosate. Isonitroso- Dimethyl Isopropyl
Cyanide. Acetoacetic Acid. Ketoxime.
Trimethyl Ethylene Nitrosochloride, (CH3)2CC1.C(NO)HCH8, and Trimethyl
Ethylene Nitrosobromide, (CH8)2.CBrC(NO)HCH3, behave similarly to the
nitrosites and nitrosates. They are prepared by the action of HC1 and HBr
respectively on a mixture of amyl nitrite and trimethyl ethylene. They easily
polymerize to their colourless dimers, which pass on melting to the blue form.
Prolonged heating converts them by isomerization into true colourless halogen
ketoximes, (CH3)2CC1.C(NOH)CH8, m.p. 50°, and (CH8)2CBr.Cl(NOH)CH8,
m.p. 79° (B. 37, 532).
Dimethyl Ethyl Ethylene Nitrosochloride, (CH8)2CCl.C(NOH)CtH,, m.p. 78°.
Diethyl Methyl Ethylene Nitrosate, (C2H6)2C(ONO2).C(NOH)CH8, m.p. 81° with
decomposition.
The nitrosate and nitrosite reactions assume some importance among the
terpenes (Vol. II.).
346 ORGANIC CHEMISTRY
4. DIALDEHYDES
The dialdehydes, ketone aldehydes, and diketones constitute a
closely united series of compounds, connected together by many
characteristics. They are subdivided according to the position of
the two CO groups relatively to each other : a- or 1,2-, 0- or 1,3, y-
or 1,4, 8- or 1,5, diketo-compounds, of which the characteristic re-
actions will be described amongst the diketones (pp. 348, 355).
Glyoxal, Oxaldehyde Diformyl [Ethane-dial], CHO.CHO, m.p. about
15°, b.p. 51°, D2o=i'i4> was discovered by Debus in 1856. It is the
dialdehyde of ethylene glycol and of oxalic acid, whilst glycolyl
aldehyde (p. 339) represents the first or half aldehyde of ethylene
glycol and the aldehyde of glycollic acid :
CH2OH CH2OH CHO
I I I
CH2OH CHO CHO
Glycol. Glycolyl Aldehyde. Glyoxal.
Glyoxal, glycollic acid and glyoxylic acid are formed by the careful
oxidation of ethylene glycol, ethyl alcohol (B. 14, 2685 ; 17, R. 168), or
acetaldehyde with nitric acid. It can also be formed from dihydroxy-
tartaric acid by the interaction of its sodium salt and sodium bisulphite
(B. 24, 3235) :
It may also be prepared from the breaking down of ajS-olefine aldehydes (p. 84)
by ozone, as in the case of heating cinnamic aldehyde ozonide (see Vol. II .) with water.
By this means a trimeric glyoxal (CHO.CHO) s is obtained, whilst the other
methods result in the production of a polymeric paraglyoxal, (CHO.CHO)« when
the aqueous solution of glyoxal is evaporated. This amorphous powder melts
with difficulty. When heated with P2O6 it is converted into the monomolecular
glyoxal, in the form of golden yellow crystals and a yellow green vapour, with
the pungent odour of formaldehyde. It dissolves in non-aqueous solvents to a
yellow solution. The colours are characteristic, since all bodies which contain the
a-diketo-group — CO.CO — possess a more or less strongly developed colour, usually
yellow to orange. In a small quantity of water glyoxal polymerizes to paraglyoxal ;
in more water, it dissolves with a generation of heat to the monomolecular
colourless hydrate, HCO.CH(OH)a or (HO)aCH.CH(OH)2. The aqueous solutions
of the various modifications all give the same reactions, except with Fehling's
solution, which is reduced only by the trimeric glyoxal (Harries, B. 40, 165).
Reactions. — The alkalis convert it, even in the cold, into glycollic acid. In
this change the one CHO group is reduced, whilst the other is oxidized (comp.
Benzil and Benzilic Acid, Vol. II.) :
CHO CHaOH
I +HaO=|
CHO COH
It reduces ammoniacal silver solution with the formation of a mirror, and unites
with two molecules of sodium hydrogen sulphite to form a crystalline glyoxal
sodium sulphite, CaH2O2(SO3HNa)2+H2O. Ethyl alcohol and a little HC1
give rise to Glyoxal Tetraethyl Acetal, (C2H5O)aCH.CH(OC2H5)2, b.p.14 89° (B.
40, 171). Similarly, glyoxal and glycol form Glyoxal Diethylene Acetal,
CaH4 : OaCH.CHOa : CaH4, m.p. 134° (B. 28, R. 321).
Glyoxal bisulphite reacts completely with primary and secondary bases to
form glycocolls or indole sulphonic acids (Vol. II.) according to the amino- base
employed (B. 27, 3238).
The action of concentrated ammonia on glyoxal results in the formation of
two bases, glycosine,
CH— NH NH— CH CH— NH
>C— C< || and Glyoxaline \\ >CH (A. 277, 336).
N CH CH-N
The latter, which preponderates, is formed still more completely from glyoxal,
two molecules of NH, and formaldehyde, and is the parent substance of the
DIALDEHYDES 347
glyoxalines (oxalines) or imidazoles (pyrro [b] monozoles) (see Vol. II.). Behaviour
towards o-phenylene diamine, comp. a-Diketones, p. 348.
Ring-forming Reactions. — Just as formaldehyde unites with hydrocyanic acid
to form the nitrile of glycollic acid, and acetaldehyde the nitrile of lactic acid, so
glyoxal combines to form the nitrile of tartaric acid. On the condensation of
glyoxal with malonic ester and acetoacetic ester, see B. 21, R. 636.
Glyoxime (see p. 354), Glyoxal Osazone (see p. 356)-. Urea combines with
glyoxal to form glycoluril (q.v.), a diureide.
Acetaldehyde Disulphonie Acid, CHO.CH(SO3H)2, can be considered as being a
derivative of glyoxal. It is prepared (i) in the form of its bisulphite compound,
when chloral is warmed with potassium sulphite ; (2) by the saturation of fuming
sulphuric acid with acetylene (comp. pp. 87, 210) ; (3) by the action of fuming
sulphuric acid on acetaldehyde (C. 1902, I. 405). By warming with alkalis it
passes straight into the salts of formic and methionic acids (A. 303, 114). The
dialkylamides of acetaldehyde disulphonic acid are obtained from sodium
methionic dialkylamides and formic ester :
HCOOCH8+NaCH(SOaNR2)2 > HCO.CH(SO2NR2)2 or
HOCH:C(SO2NR2)2,
which, on account of its acid character probably contains the hydroxymethylene
group (comp. p. 343 ; communicated by G. Schroeter). Further derivatives of
glyoxal are those which result from the action of 2HC1O, 2HBrO, and 2Br2 on
acetylene — dichlor acetaldehyde, CHC12CHO, dibromacetaldehyde, CHBr2CHO
(comp. p. 203), acetylene tetrabromide, CHBr2.CHBr2 (p. 96).
Malonic Dialdehyde, CH?(CHO)2, has not yet been isolated. If j8-hydroxy-
propionic acetal (p. 338) is oxidized with ozone, an aqueous solution is obtained
which appears to contain an aldehyde. Ethoxymethylene Acetal, fi-Ethoxyacrolein
acetal, C2H6OCH : CH.CH(OC2H5)2, is prepared from propiolic aldehyde (p. 216)
by heating it with alcoholic sodium alcoholate ; from acrolein dibromide (p. 215)
by heating it with alcohol and then with alcoholic potassium hydroxide. Its
solution in water possesses an acid reaction and reddens ferric chloride solution,
since it has been converted into malonic dialdehyde, or its desmotrope fi-hydroxy-
acrolein (comp. Hydroxymethylene Ketone, p. 343).
HOC.CH2CHO or HOCH : CH.CHO.
Similarly, propiolic aldehyde heated with aniline hydrochloride yields
fi-aniline-acrolein anil, C6H6NHCH : CH.CH : NC6H6, m.p. 115° (B. 36, 3658,
3668). Propane Tetraethyl Sulphone, CH2[CH(SO2C2H5)2]2, m.p. 1 54°, is derivable
from malonic dialdehyde, and is synthetically prepared by the condensation of
formaldehyde with two molecules of methylene diethyl sulphone (p. 209) (B. 33,
1123).
Succinic Dialdehyde [Butane-dial], CHO.CH2.CH2.CHO, b.p.10 67°, can be
obtained from diallyl (p. 90) by means of ozone ; but is most conveniently
prepared by breaking down its dioxime (p. 355), obtained from pyrrole, by N2O3.
It is isomeric with butyrolactone (p. 374), and is also looked on as being the
hydrate of furfurane, from which it can be obtained by the action of HC1 in
methyl alcohol, in the form of its tetramethyl acetal, CH(OCHS)2CH2CH(OCH3)2,
b.p. 202°. The tetraethyl acetal, b.p.20 116°, results from the electrolysis of the
sodium salt of j8-diethoxypropionic acid (C2HBO)2CHCH2COOK (B. 39, 891).
Succinic dialdehyde polymerizes readily to a glassy substance from which it is
regenerated on distillation (Harries, B. 35, 1183 ; 39, 3670). When heated with
water it forms furfurane, with ammonia pyrrole, and with P«S, thiophene (comp.
i)4-Diketones, p. 351).
Dibromosuccinic Aldehyde, HCO.CHBr.CHBr.CHO, m.p. 73°, is prepared
from the aldehyde and bromine.
Bromofumar aldehyde, HCO.CH:CBrCHO, b.p.15 130°, is obtained by distillation
of the previous compound.
On the breaking down of furfurane into Nitrosuccinaldehyde, and the conversion
of the latter, by boiling with water, into Fumaric Dialdehyde, CHO.CH : CH.CHO,
see C. 1902, I. 1272. Dibromomaleic Dialdehyde, CHO.CBr : CBrCHO, m.p. 69°,
is obtained from jSy-dibromopyroracemic acid and bromine water (A. 232, 89).
Glutaric Dialdehyde, HCOCH2CH2CH2CHO, is not yet known. Of its
derivatives, Glutaconic Dialdehyde, HCO.CH : CH.CH 2.CHO is obtained during the
decomposition of pyridine (Vol. II.) ; and an a-Chloroglutaconic Dialdehyde,
HCO.CC1 : CH.CHa.CHO, results when phenol (Vol. II.) is decomposed. The
348 ORGANIC CHEMISTRY
latter gives rise to j8-chloropyridine with ammonia, and a-thiophene aldehyde
with H.S (B. 38, 1650).
Adipic Dialdehyde [Hexane-dial], CHO.[CH2]4CHO, b.p., 93°. is obtained
from a.ax-dihydroxysuberic acid by oxidation with PbO2. Its Tetraethyl Acetal,
(C2H6O)2CH[CH2]4CH(OC2H6)2, b.p.1(? 148°, results from the electrolysis of the
potassium salt of y-diethoxybutyric acid. The aldehyde polymerizes more slowly
than the higher and lower homologues, although heating with water condenses it
rapidly to cyclopentene aldehyde (Vol. II.) (B. 39, 891).
Suberic Dialdehyde [Octane-dial], CHO[CH2]6CHO, b.p.80 142°, is prepared
from dihydroxyadipic acid and PbO2. It polymerizes very easily (B. 31, 2106).
The oximes, hydrazones and osazones of the dialdehydes are described together
with the corresponding compounds of the aldehyde-ketones and diketones (p. 353).
5. KETONE- ALDEHYDES OR ALDEHYDE-KETONES
a-Ketone-aldehydes.
Pyroracemic Aldehyde, Acetyl Forntyl, Methyl Glyoxal [Propanalone],
CH,CO.CHO, results from the breaking down of mesityi oxide, CH3.CO.CK :
C(CHS)2, by means of ozone. Dilute acids precipitate it from its oxime, isonitroso-
acetone (p. 3^4). It is a yellow volatile oil, which polymerizes readily.
Methyl Glyoxal Acetal, CH8COCH(OC2H6)2, b.p.,0 30° (B. 38, 1630).
Derivatives include Dichlor acetone, CH8COCHC12, b.p. 120° (comp. p. 224),
produced from allylene and 2HC1O. Dibromacetone, CH8COCHBr2, b.p. 142°,
results from allylene and 2HBrO. Similarly, Dichlor opinacoline, (CH3)3C.CO.-
CHC12, m.p. 51°, andDibromopinacoline, (CH3)3C.COCHBr2, m.p. 75°, are obtained
from tert.-butyl acetylene. Derivatives of tert.-Butyl Glyoxal (C. 1900, II. 29).
Propanal Disulphonic Acid, CH8C(SO3H)2CHO, is prepared from propionic
aldehyde and fuming sulphuric acid (C. 1902, I. 405). It corresponds with
acetaldehyde disulphonic acid.
Isobutyrie Formaldehyde, Isopropyl glyoxal [3-Methyl-butanal-2-one],
(CH3)2CH.COCHO, m.p. 95°, is produced from dimethyl butanonal acid by
fusion or by boiling with water (B. 30, 861).
0-Ketone Aldehydes, such as formyl acetone, CH3.COCH2CHO, have already
been described (p. 343), since in the free state they assume the aci- con-
figuration, which leads to their inclusion with the B-Hydroxymethylene Ketones or
Olefine Ketols.
y-Ketone Aldehydes.
LsBVulinic Aldehyde [Pentanal-4-one], CH3.CO.CH2.CH2CHO, b.p.7eo 187°,
b.p.ja 70°, is obtained from its methylal, b.p.18 86°, the reaction product of a
boiling solution of hydrochloric acid in methyl alcohol on a-methyl furfural or
sylvan (B. 31, 37).
6. DIKETONES
The relative position of the CO-groups determines them to be
either a- or i,2-diketones, j3- or i,3-diketones, y- or i,4-diketones, etc.
They have been regarded as diketo-substitution products of the paraffins,
hence the name. The " Geneva names " contain the syllable " di " between
the paraffin name and the ending " one " ; thus [Butane-dione] for CH8.CO.COCH8.
The a-diketones are most generally designated as compounds of two acid radicals,
e.g diacetyl for CH3CO.COCH3 ; the 0-diketones as monoketones containing acid
radicals, e.g. acetyl acetone, CH3CO.CH2.CO.CH8.
The diketones react like the monoketones with hydroxylamine and phenylhy-
drazine. Their oximes, prepared in another manner, constitute the chief raw
iterial from which to prepare the a-diketones. The nitrogen-containing
jrivatives of the diketones, the aldehyde ketones and dialdehydes will be dis-
cussed after the diketones, because of their greater significance in this position.
i'or the mercaptol and sulphone formation of the diketones, see B. 35, 493.
(i) a- or i,2-Diketones.
^•7heSfv a^e obtained (*) from their monoximes, the isonitroso-ketones, by
Limg the latter with dilute sulphuric acid (v. Pechmann) (B. 20, 3213 ; 21,
at ' ' ?27' 532 ; 24' 3954 : C. 1904, II. 1701) ; (see pyrovacemic aldehyde).
They are also formed (2) by the oxidation of the a-ketoles, e.g. the synthetic
DIKETONES 349
acylolns (p. 341); and (3) accompanied by dinitro-paraffins (p. 154), when mono-
ketones or the corresponding secondary alcohols are oxidized by nitric acid
(B. 28, 555 ; C. 1900, II. 624 ; 1901, II. 334) ; (4) from a-bromolefine ketones
containing the group — C : CBrCO — , instead of the expected o-olefine ketone-
alcohols (p. 343), (B. 34, 2092).
The a-diketones, in contradistinction to the colourless aliphatic monoketones,
are yellow, volatile liquids with a penetrating quinone-like odour ; comp.
glyoxal (p. 346). On the absorption spectra of a-diketones, see C. 1906, II. 495.
(i) The a-diketones are characterized and distinguished from the ft- and
y-ketones by their ability to unite with the orthophenylene diamines (similarly
to glyoxal). In this way they are condensed to the quinoxalines (q.v.) :
a CO.R ,N:CR
+| =C,H/ | +2HaO.
NHa CO.R \N:CR
All compounds containing the group — -CO. CO — , e.g. glyoxal, pyroracemic
acid, glyoxylic acid, alloxan, dihydroxytartaric acid, etc., react similarly with the
o-phenylenediamines. (2) The glyoxalines are the products of the union of the
a-diketones with ammonia and the aldehydes :
CH3.CO CH3C— NH.
1 +2NH,+CHa.CHO = || \C.CH3+3H20.
CH3.CO CH,C N^
(3) Nucleus- synthetic reactions :
a-Diketones, containing a CH2-group, together with the CO-group, undergo a
rather remarkable condensation when acted on by the alkalis. A Idols are first
produced, and later the quinones (B. 22, 2215 ; 28, 1845) :
CH8.CO.CO.CH, CH,.C(OH).CO.CH, CH8.C.CO.CH
yield I and || ||
CH3.CO.CO.CH8 CH2.CO.CO.CH, HC.CO.C.CH,.
2 Molecules Diacetyl. Diacetyl Aldol. p-Xyloquinone.
(4) Diacetyl and hydrocyanic acid yield the nitrile of dimethyl racemic acid
(see glyoxal) (B. 22, R. 137).
Diacetyl, CH3.CO.CO.CH3, Diketobutane, Dimethyl Diketone, Dimethyl Glyoxal
[Butane-dione], b.p. 87-89°, is obtained (i) from isonitroso-ethyl methyl ketone
by the breaking down action of dilute sulphuric acid (B. 40, 4337) ; (2) from
methyl ethyl ketone or methyl ethyl carbinol by oxidation with nitric acid :
it is accompanied by dinitro-ethane (p. 155) ; (3) from oxalic diacetic or ketipic
acid, COOH.CHjCO.CO.CH2COOH, by elimination of 2CO2 by heat (B. 20, 3183) ;
(4) by oxidation of tetrinic.acid (q.v.) by KMnO4 (B. 26, 2220 ; A. 288, 27) ; (5)
by electrolysis of pyroracemic acid, CH3CO.COOH (B. 33, 650) ; (6) from vinyli-
dene oxanilide, an oxalic acid derivative, and methyl magnesium iodide (B. 40,
186). When shaken with hydrochloric acid, diacetyl polymerizes to the trimeric
(CH3CO.COCH3)3, m.p. 105°, b.p. 280°, which decomposes on prolonged heating
(B. 35, 3290 ; 36, 954)-
Tetrachlorodiacetyl, CHC12.CO.CO.CHC12, m.p. 84°, results in the action
of potassium chlorate on chloranilic acid (together with tetrachloracetone,
p. 224) (B. 22, R. 809 ; 23, R. 20).
Tetrabromodiacetyl, (CHBr2.CO)8 (B. 23, 35) and Dibromodiacetyl,
(CH2Br.CO)2, are produced by the action of bromine on diacetyl.
Acetyl Propionyl, CaH5.CO.CO.CH3, Methyl Ethyl Diketone [2,3-Pentane-dione],
b.p. 1 08°, is obtained from isonitroso-diethyl ketone ; also by the hydrolysis
of a-bromethylidene acetone, CH3CH:CBrCOCH3 (B. 34, 2092). It condenses
to duroquinone. Acetyl Butyryl [2,3-Hexane-dione], C3H7COCOCH3, b.p. 128°,
Acetyl Isobutyryl, (CH3)2CHCO.COCH3, b.p. 115°, results from the hydrolysis
of acetoxymesityl oxide (p. 343). Acetyl Isovaleryl, (CH3)2CHCH2 COCOCH3,
b.p. 138°. Acetyl Caproyl, CH3[CH2]4COCOCH3, b.p. 172° (C. 1898, II. 965 ;
1900, II. 624). Acetyl Isocaproyl, (CH3)2CHCH2CH2COCOCH3, b.p. 163° (B.
22, 2117 ; 211, 3956).
Symmetrical diketones : Dipropionyl, CH3CH2CO.COCH2CH3. Dibutyryl,
CH,CH2CH2CO.COCH2CH2CH3, b.p. 168°. Di-isobutyryl, (CH3)2CHCO.CO-
CH(CH3)2, b.p. 145°. Di-isovaleryl, (CH3)2CHCHaCO.COCHaCH(CH,),.
35o ORGANIC CHEMISTRY
,611,.. Z)*>i>fl/oy/,(CH8)3C.CO.CO.C(CHs)tI
b.p. 170°. All these bodies are obtained from the a-ketols, the acyloi'ns (pp. 315,
341) by oxidation with nitric acid or dehydration by means of finely divided
copper (J. pr. Ch.[2] 62, 364 ; C. 1906, II. 1115).
a-Diketone Dichlorides result in the action of hypochlorous acid on alkylated
acetylenes (p. 89), according to the equation :
C2H6C:CCH3+2HC10=C2H6CC12.COCH,+H20.
Methyl a-Dichloropropyl Ketone, C2H6.CC12.CO.CH3, b.p. 138°, yields methyl n-
propyl ketone on reduction ; with potassium carbonate solution it forms duro-
quinone, angelic acid (p. 298), and a-ethyl acrylic acid. The two acids result from
an intramolecular atomic rearrangement which recalls that of the formation of
benzilic acid from benzil (p. 38).
(2) j8- or i,3-Diketones are produced according to two nucleus-synthetic
reactions : (i) like the hydroxymethylene ketones, by the interaction of acetic
esters and ketones in the presence of sodium ethoxide, or, better, metallic sodium
(Claisen, B. 22, 1009 ; 23, R. 40; 38, 695)-
The condensation probably proceeds similarly to that leading to the formation
of hydroxymethylene ketones (p. 343) and of acetoacetic ester (p. 412) ; the
first step consists in the action of sodium or its compounds on the ester, the second
in condensation and elimination of alcohol with the formation of the sodium
salt of the ad- form of the j3-diketone :
2H6 Na.OC2H5
+CH3COCH3 - ^-^7-> CH1C==CHCOCH,+C1HiOH»
*
(2) By the action of A1C13 on acetyl chloride and the subsequent decomposi-
tion of the aluminium derivative. This reaction was discovered by Combes, but
correctly interpreted by Gustavson (B. 21, R. 252 ; 22, 1009 ; C. 1901, I. 1263) :
3
—CO. CH8— CCKrw
CH3CO'i2 — - CH3COa - > CH3— CO>CH»'
(3) Acyl acetoacetic ester (p. 419), when heated with water at 140-150°
decomposes into CO2, alcohol and /3-diketone (acyl acetone) (C. 1903, I. 225) :
CH3CH2CH2COv. pTTpn r ti «2o CH3CH2CH2COv. rv[ , p^ . /-» TT ^NTI
CH CO 2 2 B - — ^" gucO^^^*-**^^
Constitution. — The j8-diketones, like the hydroxymethylene ketones (p. 343),
have an acid character. Although the formyl ketones are regarded as hydroxy-
methylene derivatives, the disposition generally is to assign to the salts of the
jS-diketones, e.g. CH3.CO.CH=C(ONa)CH3, the keto-enol formula, retaining
for the free ketones, however, the diketo formula. Comp. also acetoacetic ester,
and formyl acetic ester (A. 277, 162). The molecular refraction is an argument in
favour of this view (B. 25, 3074).
Reactions. — A very characteristic reaction is the precipitation of their alkali
salts by copper acetate. Ferric chloride imparts an intense red colour to their
alcoholic solution.
When the salts of j3-diketones are treated with iodoalkyls, the CHa-group
becomes alkylated (comp. Acetoacetic Ester) :
C2H6ONa
CH3COCH2COC3H7 „„ > CH,COCH(CH3)COC3H7.
LHjI
Hydroxylamine converts the /3-diketones into isoxazoles, phenyl-hydrazine into
pyrazoles (pp. 354, 356).
Acetyl Acetone, CH,CO.CHa.CO.CH3, b.p. 137° (above, for its forma-
tion). Electrolysis of an alcoholic solution of sodium acetyl acetone, or the
action of iodine on the same body, leads to the formation of tetra-acetyl ethane
(B. 26, R. 884). With S2C12 and SC12 it forms dithio- and monothio-acetyl acetone
respectively (B. 27, R. 401, 789). H2S produces a dimeric Dithioacetyl Acetyl
Acetone (C6H,S2)a, m.p. 163 (C. 1901, II. 397). Cyanogen unites with acetyl
acetone in presence of a little sodium ethoxide to form Cyanimidomethyl Acetyl
DIKETONES 351
Acetone, NC.C(NH).CH(COCH3)2, m.p. 130°, and Diimidotetra-acetyl Butane,
(CH3CO)2C(NH)C(NH)CH(COCH3)2, m.p. 147° (B. 31, 2938).
The metallic salts of acetyl acetone resemble one another in their remarkable
stability. Those of Be, Al, Cr, Mn, Zn, Fe, Cu, Hg, Mo, Ft", Ce, La, Th, and
others have been prepared, of which some, on account of their power of crystalliza-
tion, have been employed for the determination of the valency and atomic weights
of the rare elements (C. 1900, I. 588 ; B. 34, 2584 ; A. 331, 334). Copper Acetyl
Acetone, Cu(C6H7O2)2. Beryllium Acetyl Acetone, Be(C6H7O2)2, m.p. 108°, b.p.
270°. Aluminium Acetyl Acetone, A1(C8H7O2)3, m.p. 193°, b.p. 314°. The
vapour density of these compounds reveals the divalence of Br and the trivalence
of Al. Chromium Acetyl Acetone, Cr(C6H7O2)3, b.p. 340°, is of a violet colour,
and gives off a green vapour (Coombes, B. 28, R. 10 ; C. 1899, II. 525).
Octochlor acetyl Acetone, m.p. 53, and Octobromacetyl Acetone, CBr3COCBr2-
COCBr3, m.p. 154°, are obtained from phloroglucinol, and chlorine or bromine
respectively (Vol. II.) (B. 23, 1717).
Alkylated acetyl acetones are obtained from acetyl acetone by sodium and
iodo-alkyls (B. 20, R. 283 ; 21, R. n).
Acetyl Methyl Ethyl Ketone, Acetyl Propionyl Methane, CH3COCH2COC2H5,
b.p. 158°. Acetyl Methyl Propyl Ketone, Acetyl Butyryl Methane, b.p. 175° (B. 22,
1015 ; C. 1903, I. 225). Acetyl Isobutyryl Methane, b.p. 168° (B. 31, 1342 ;
C. 1900, II. 317). Acetyl Caproyl Methane, CH3[CH2]4COCH2.COCH3, b.p.20
100°, also results from acetyl cenanthylidene (p. 232) and sulphuric acid (C. 1900,
II. 1262 ; 1903, I. 225).
Higher £-diketones : see C. 1902, I. 568.
(3) y- or i,4-Diketones.
These correspond with the paraquinones of the aromatic series (q.v.).
They are not capable of forming salts, hence are not soluble in the
alkalis. They form mono- and di-oximes with hydroxylamine, and
mono- and di-hydrazones with phenylhydrazine ; these are colour-
less. The readiness with which the y-diketones form pyrrol, furfurane,
and thiophene derivatives is characteristic of them.
Acetonyl Acetone, sym.-Diacetyl Ethane, [2,5-Hexane-dione], CH3-
CO.CH2CH2COCH3, m.p. —9°, b.p. 194°, D20= 0-973, is obtained
from pyrotritaric acid, C7H8O3 (q.v.) ; from acetonyl acetoacetic
ester (q.v.), when heated to 160° with water (B. 18, 58) ; and from
isopyrotritaric acid and diacetyl succinic ester, when they are boiled
with potassium carbonate solution (B. 33, 1219). It is a liquid with
an agreeable odour, and is miscible with water, alcohol, and ether.
Conversion of Acetonyl Acetone into I, ^-Dimethyl Furfurane, -Thio-
phene, and -Pyrrole (Paal, B. 18, 58, 367, 2251).
(1) The direct removal of one molecule of water from acetonyl
acetone by distillation with zinc chloride or P2O6 results in the formation
of dimethyl furfurane (B. 20, 1085) :
CH2.CO.CH3 CH =
= | >0 +H,0.
CH2.CO.CH8 CH =CCCH
Dimethyl Furfurane.
Other y-diketone compounds react in a similar manner (Knorr, B. 17,
2756).
(2) When heated with phosphorus sulphide acetonyl acetone yields
dimethyl thiophene :
CH2.CO.CH3 CH=C<fCHs
| +H2S=| >S +2H.O.
CH8.CO.CH, CH =C<CH
Dimethyl Thiophene.
352 ORGANIC CHEMISTRY
All the y- diketones or i,4-dicarboxyl compounds, e.g. the y-ketonic
acids (q.v.), yield the corresponding thiophene derivatives upon like
treatment (B. 19, 551).
(3) Dimethyl Pyrrole is produced on heating acetonyl acetone with
alcoholic ammonia :
CH2.CO.CHt CH=C^CH»
I +NH,= I >NH +2H.O*
CHj.CO.CH, CH==C\CH3
Dimethyl Pyrrole.
All compounds containing two CO-groups in the imposition
react similarly with ammonia and amines, e.g. diacetosuccinic ester
and Izevulinic ester. All the pyrrole derivatives formed as above,
when boiled with dilute mineral acids, have the power of colouring a
pine chip an intense red. This reaction is, therefore, a means of
recognizing all i,4-diketone compounds (B. 19, 46).
In all these conversions of acetonyl acetone into pyrrole, thiophene,
and furfurane derivatives, it may be assumed that it first passes from
the diketone form into the pseudo-form of the diolefine glycol (p. 38) :
CHj.CO.CH, CH=C<™*
| yields |
CH..CO.CH, CH=C<°£
and from this, by replacing the 2OH-groups with S, 0, or NH, the
corresponding furfurane, thiophene, and pyrrole compounds are pro-
duced (B. 19, 551).
w-Di methyl Lsevulinic Methyl Ketone, a-Di methyl Acetonyl Acetone,
(CH3)2CH.CO.CH2CH2COCH3, b.p.j, 91°, is a degradation product of tanacetone,
a terpene ketone (Vol. II.). It is prepared from methyl heptenone glycol,
(CH8)2C(OH).CH(OH).CH2CH2.COCH8, by boiling with sulphuric acid (B. 35,
1179).
1,5- or 8 -Diketones are not known. If it is attempted to prepare them from
the 8-diketone dicarboxylic esters, e.g. aa-diacetyl glutaric ester :
C,H6OCO>CHCH»CH<COOC*H§
(resulting from the condensation of aldehydes and acetoacetic esters) by splitting
off carboxyethyl groups, there results instead of, for example, diacetyl propane
or 2,5-heptane-dione, CH8CO.CH2CH2CH2.COCH8, a carbocyclic condensation
product— 3-Methyl- A 2-R-hexene (A. 288, 321).
1.6- or e-Diketones. Diacetyl Butane [2,7-Octane-dione], m.p. 44°, results
from the electrolysis of potassium laevulinate :
2CH,COCH2CH2 j COO j K > CH3COCHaCH2.CH2CHa.COCH8.
It is also obtained by the ketonic decomposition of diacetyl adipic ester (q.v.)
(B. 33, 650).
1.7- or £-Dlketone, Diacetyl Pentane, CH,CO.(CH2)5.COCH8, belongs to this
class. When reduced, it undergoes an intramolecular pinacone formation and
becomes Dimethyl Dihydroxyheptamethylene, CH8.C(OH)[CH.]5C(OH)CH8 (B. 23,
R. 249 ; 24, R. 634 ; 26, R. 316).
DIKETONES 353
NITROGEN-CONTAINING DERIVATIVES OF THE DIALDEHYDES, ALDE-
HYDE KETONES AND DIKETONES
1. For the action of ammonia on glyoxal and acetonyl acetone, consult
pp. 346, 352.
2. Oximes.
A. Monoximes. — (a) Aldoximes of the a-aldehyde ketones and monoximes of the
a-diketones : isonitrosoketones or oximido-ketones. These bodies are formed
(ia) by the action of nitrogen trioxide on ketones (B. 20, 639). By this re-
action mixed ketones, which contain the — CO — group united to two CHa-groups,
yield two different isonitroso-ketones ; but if the — CO — group is joined to a
tertiary alkyl, only one isonitroso-ketone is formed (C. 1898, II. 965).
(16) When amyl nitrite in the presence of sodium ethoxide or hydrochloric
acid acts on ketones. Sometimes one and sometimes the other reagent gives
the best yield (B. 20, 2194 ; 28, 1915) :
CH3COCHs+NO.O.CfiH11=CH8COCH(N.OH)+C5H11.OH.
An excess of amyl nitrite decomposes the oximido-body, whereby the oximido-
group is replaced by oxygen, with the production of a-diketo-derivatives (B. 22,
527 ; C. 1904, II. 1701).
(2) Just as acetone is formed from acetoacetic ester, so can isonitroso- or
oximido-acetone be prepared from the oximido-derivative of acetoacetic ester
(B. 15, 1326). Nitrous acid decomposes acetoacetic acid into oximido-acetone
and carbon dioxide :
CH8COCH2COaH+NO.OH=CH8.COCH(N.OH)+C02+H20.
Similarly, by the action of nitrous acid, nitrosyl sulphate or chloride, the oximido-
compounds of the higher acetones can be directly derived from the monoalkylic
acetoacetic acids and their esters by elimination of carbon dioxide (B. 20, 531 ;
C. 1904, II. 1700) :
CH,COCH<£0 H+NO.OH=CH,COC<^ QH+CO2+HaO,
whilst the dialkylic acetoacetic acids do not react (B. 15, 3067).
Properties. — The isonitroso- or oximido-ketones are colourless, crystalline
bodies, easily soluble in alcohol, ether and chloroform, but usually more sparingly
soluble in water. They dissolve in the alkalis, the hydrogen of the hydroxyl
group being replaced by metal, with the formation of salts having an intensely
yellow colour. They yield a yellow coloration with phenol and sulphuric acid,
and not the blue coloration of the nitroso-reaction (B. 15, 1529).
Reactions. — (i) As in the ketone-oximes, so also in the isonitroso-ketones, the
oximido-group can be split off and be replaced by oxygen, which will lead to the
formation of diketo-bodies, — CO.CO — . This result may be brought about by
the addition ol sodium bisulphite and boiling the resulting imidosulphonic acid with
dilute acids (B. 20, 3162). The reaction also takes place when isonitrosoketones
are boiled directly with dilute sulphuric acid (B. 20, 3213). The decomposition is
sometimes more readily effected by nitrous acid (B. 22, 532 ; C. 1904, II. 1701).
(2) The aldoximido-ketones, like the aldoximes (p. 212), are converted by dehy-
drating agents — e.g. acetic anhydride — into acidyl cyanides or a-ketone'carboxylic
nitriles (q.v.) (B. 20, 2196).
(3) Aminoketones (p. 344) are produced in the reduction of isonitroso-ketones
by means of stannous chloride.
(4) Two molecules of phenylhydrazine, acting on the isonitroso-ketones,
produce osazones, e.g. CH8.C(N2H.C,H8)CH(N2H.C6H6) — acetonosazone (B. 22,
528). Semicarbazide gives rise to semicarbazone oximes, most of which are slightly
soluble and possessed of high melting points (C. 1904, II. 304, 1700).
(5) By the further action of hydroxylamine or its hydrochloride (B. 16, 182 ;
C. 1904, II. 1700) on isonitroso-acetone, the ketone oxygen is replaced and
dioximes of the a-aldehyde ketones and a-diketones are produced.
(6) Halogen alkyls acting on the salts of isonitroso-ketones produce ethers
(comp. B. 15, 3073 ; 38, 1917) :
CH3CO.C(NOK)CH8+CHtI=CH3CO.C(NOCHI).CH8+KI.
VOL. I. 2 A
354 ORGANIC CHEMISTRY
of the a-diketones. They are more stable than the free
are therefore more suitable for use in many synthetic
reactions.
Isonitroso-acetone, Aldoxime of Pyroracemic Aldehyde, CH3.CO,
CH-(NOH) m.p. 65°, is very readily soluble in water; crystallizes in
silvery 'glistening tablets or prisms ; melts and decomposes at higher
temperatures, but may be volatilized in a current of steam.
Monoximes of the a-Diketones.— Isonitroso-ethyl Methyl Ketone, CH8CO.C =
NOHCH mp "4° bp. 185-188°. Preparation (B. 35, 3290). Action of
HC1 on is'onitroso'ethyl methyl ketone (B. 38, 3357)- Isonitroso-methyl Propyl
Ketone. CH,CO.C=NOH.CH2CH3, m.p. 52-53°, b.p. 183-187°. ^omtroso-
diethyl Ketone, C2H5.COC=NOH.CH3, m.p 59-62°. Isom roso-methyl Butyl
Ketone, CH8.COC=NOH.C3H7, m.p. 49;5°. . Isomtroso-methyl Isobutyl Ketone,
CH3.COC=NOH.CH(CH8)2, m.p. 75°- Isomtroso-methyl Isoamyl Ketone CH3.-
COC=NOHCH,.CH(CH8)2, m.p. 42° C. Isomtroso-methyl Isocapryl Ketone,
CH8.COC=NOH.CHaCH,CH(CH8)a, m.p. 38°.
For other isonitroso-ketones see C. 1899, I. 190 ; II. 524 '> 1904, U- 17°°-
B Oxime-anhydrides of the jS-Diketones or Isoxazoles.
Monoximes of the fi-formyl ketones and of the 0-diketones are not known.
In the attempt to prepare them water is lost and an intramolecular anhydride
formation takes place. The oxime-anhydrides are isomeric with the oxazoles,
which also consist of five members ; hence their name, isoxazoles (B. 21, 2178 ;
24, 390; 25, 1787). CH=CH
Isoxazole, Oxime-anhydride of Malonic Dialdehyde, \ _/°' btp> 95*' is
prepared from propargyl aldehyde or j3-anilino-acrolein anil (p. 347) by hydroxyl-
amine. Alcoholic alkalis convert it into cyanacetaldehyde (p. 401 ) (B. 36, 3665) :
CH=CHV CHj.CHO
I V> - > |
CH=N/ C=N
a-Methyl Isoxazole, CH3-a-C3H2NO, b.p. 122°, and y-Methyl Isoxazole, CH3-y-
C,H,NO, b.p. 1 1 8°, result from hydroxymethylene or formyl acetone. They are
transparent liquids, having an intense odour resembling that of pyridine.
a-Methyl isoxazole readily becomes rearranged into cyanacetone (g.v.) :
CH=CHOH CH - CH CH - CO.CH, CH - C.CH,
- >• 11/3 Y II II - >• II ft Y II
CH..CO NH. ~aH20 CH.C. N CHOH NH, -aHaO CH« N
HO/ ^ HO/ N><
ay-Dimethyl Isoxazole (CH3)2-ay-C8HNO, b.p. 141*, has a very peculiar
odour, and is obtained from acetyl acetone and hydroxylamine hydrochloride.
C. Dioximes.
(a) Glyoxiraes or a-Dioximes. — When glyoxal, of which the monoxime
is not known, pyroracemic aldehyde and the o-diketones are treated with
hydroxylamine hydrochloride, the o-dioximes or glyoximes are formed. They can
also be obtained from a-isonitroso-ketones or a-dichloroketones. The glyoximes
form characteristic complex compounds with Ni, Co, Pt, Fe, Cu, which are stable
and strongly coloured ; the metal is united to two glyoxime molecules (B. 39,
2692, 3382).
Glyoxime, CH(=NOH).CH(=NOH), m.p. 178° (B. 17, 2001 ; 25, 705 ; 28,
R. 620), is prepared from trichlorolactic acid (p. 368). Methyl Glyoxime ,
Acetoximic Acid, CH8C(NOH).CH(NOH), m.p. 153°. Dimethyl Glyoxime,
Diacetyldioxime, CH8C(NOH).C(NOH)CH8, m.p. 234° (B. 28, R. 1006 ; J. pr.
Ch. [2] 77, 414) is employed as a sensitive test for the presence of Ni.(Tr).
Methyl Ethyl Glyoxime, CH8C(NOH).C(NOH).C,H6, m.p. 172° ((B. 34, 3978)-
Methyl Propyl Glyoxime, m.p. 168°. tcrt.-Butyl Glyoxime, (CH3),C.C(NOH)-
CH(NOH), m.p. 102°, is prepared from dichloropinacoline (p. 348). Methyl
DIKETONES 355
Isobntyl Glyoxime, m.p. 170-172°. Higher homologues of glyoxime, see C. 1899,
II. 524 ; 1904, II. 1700.
(6) Glyoxime Peroxides (B. 23, 3496) result when NO2 acts on an ethereal
CH3.C=N-0
solution of the glyoximes : Dimethyl Glyoxime Peroxide, I , b.p. 222°.
CH3.C=N-0
Methyl Ethyl Glyoxime Peroxide, b.p.18 115°.
(c) Furazanes, Azoxazoles, Furo-\j&&^\-diazoles are the anhydrides obtained
CH:Nv
from certain o-dioximes. Furazane, I yO, itself is not known, whilst
CH:N/
dimethyl furazane, for example, has been prepared from diacetyl dioxime.
(d) £-Dipximes, Acetyl Acetone Dioxime, CH3C(NOH)CH2C(NOH)CH3,
m.p. 150°, is produced from acetyl acetone by an excess of hydroxylamine. It
easily gives this up and is converted into dimethyl isoxazole (see above). Reduc-
tion by sodium and alcohol gives i,4-diaminopentane (p. 333). Electrolytic
reduction in sulphuric acid solution leads to the formation of Dimethyl Pyrazo-
lidine, CH3CH(NH)CH2CH(NH)CH3, a compound in which the nitrogen atoms
have become united (B. 36, 219).
(e) y-Dioximes, which may be systematically derived from the y-dialdehydes ;
y-aldehyde-ketones and y-diketones may be prepared (i) by the action of hydroxy-
lamine on pyrrole (B. 22, 1968) and alkyl pyrroles (B. 23, 1788) ; (2) from y-dike-
tones and hydroxylamine. They are decomposed by boiling alkalis into the
corresponding acids, or y-diketones ; the latter are far better obtained by means
of nitrous acid.
Succinaldehyde Dioxime, HON : CHCH2CH2CH : NOH, m.p. 173°, passes upon
reduction into tetramethylene diamine (p. 333), and into succinic dialdehyde by
the action of NaO3 (B. 35, 1184). Ethyl Succinaldioxime, HON : CHCH(C2H5)-
CH2CH : N(OH), m.p. 135°. ; Propionyl Propionaldioxime, CH3CHaC : N(OH)-
CH2CH2CH:N(OH), m.p. 85°. Methyl Lcevulinaldioxime, CH8C : N(OH)CH2-
CH(CH)3CH : N(OH). Acetonyl Acetone Dioxime, CH3C : N(OH)CH2CH,C :-
N(OH)CH3, m.p. 135°. wa>-Diacetyl Pentane Dioxime, CH,C:N(OH)[CHj]6C :-
N(OH)CH8, m.p. 172°.
3. Hydrazine and Phenylhydrazine Derivatives.
CH3C=N
Dimethyl Aziethane, \ \ , m.p. above 270°, and Dimethyl bishydrazi-
CH3C=N
NH\ /NH
methylene, \ ;>C(CH3).C(CH3K I . m.p. 158°, are obtained from diacetyl and
NHX XNH
hydrazine (J. pr. Ch. [2] 44, 174). Dimethyl aziethane is also prepared from
Diacetyl Acetylhydrazone, CH3C(N : N.COCH3) : C(OH)CH3, m.p. 167° by heating
it with alkalis. The mono-semicarbazones of the a-diketones dissolve in alkalis,
like the monoximes (p. 354), to a yellow solution. Diacetyl Semicarbazone,
CH3COC(NNHCONH2)CH3, or CH2 : C(OH).C(NNHCONH2)CH3, m.p. 235°.
Acetyl Propionyl Semicarbazone, m.p. 209° (B. 36, 3183°).
Glyoxal Disemicarbaxone (NH2CONHN : CH — )2, is a slightly soluble crystalline
powder of high melting point (B. 40, 71).
NH. ym
Glyoxal Bisguanidine, >C-NHN:CH.CH:NHNC^ +H2O, m.p. 265,
NH/ XNHa
with decomposition, is formed from dichloraldehyde (p. 203) and amidoguani-
dine (A. 202, 284). Diacetyl Semicarbazone, m.p. 279°.
Monophenylhydrazones. — Hydraxone of Pyroracemic Aldehyde, CH8CO.CH:-
N.NH.CtH6, m.p. 148°, is obtained by hydrolyzing the reaction-product resulting
from diazobenzene chloride and sodium acetoacetic ester with alcoholic sodium
hydroxide (C. 1901, I. 299). Diacetylhydrazone, CH8CO.C:(NNHC,H5)CH8, m.p.
133°, has been prepared from diacetyl- and methyl-acetoacetic ester (Japp and
Klingemann) (A. 247, 190).
a- Acetyl Propionyl Hydrazone, CH3C(:NNHC6H5).COCH3, m.p. 97°, is obtained
from acetyl propionyl. fi-Acetyl Propionyl Hydrazone, CH8CO.C:(NNHC,H5)CHa,
m.p. 1 1 7°, is prepared from ethyl acetoacetic acid and diazobenzene chloride,
356 ORGANIC CHEMISTRY
Diphenylhydrazones or Osazones.— Glyoxal (p. 346), methyl glyoxal (p. 348),
the o-diketones and the a-isonitroso-acetones, when treated with phenylhydrazme,
lose two molecules of water or water and hydroxylamine, respectively, and
form diphenylhydrazones or osazones, which can also be obtained from
a-hydroxyaldehydes, o-hydroxyketones, a-aminoaldehydes and a-aminoketones.
The osazones have become especially important for the chemistry of the aldo-
pentoses and the aldo- and ketohexoses. The osazones are oxidized by potassium
chromate and acetic acid to osotetrazones, which are converted by hydrochloric
acid and ferric chloride into osotriazones :
CH8C=N— NHC,H6 o CH3C=N— NC8H5 Fe2ci8 CH8C=N
CH3C=N-NHC.H5 CH3C=N-NC.H6 HCl CH,C-«
Diacetyl Osazone. Diacetyl Osotetrazone. Diacetyl Osotnarone.
Glyoxal Osazone, C6H6NH.N:CHCH:N.NHC6H5, m.p. 177°, is also prepared
from formaldehyde and phenylhydrazine, with the intermediate formation of
CH:N.NC6H5
glycolyl aldehyde (p. 337) (B. 30, 2459). Glyoxal Osotetrazone, \ \
m p. 145° (B. 17, 2001 ; 21, 2752 ; 26, 1045). Methyl Glyoxal Osazone, C6H5NH.-
N:C(CH3)CH:N.NHC6H6, m.p. 145° (B. 26, 2203). Methyl Glyoxal Osotetrazone,
CH:N.N.C6H5 CH:Nv
, m.p. 107°. Methyl Glyoxal Osotriazone, ">NC,HM
CH3C=N.N.C.H5 CH3C=N/
b.p.10 150° (B. 21, 2755). Diacetyl Osazone (formula above), m.p. 236° with de-
composition (B. 20, 3184 ; A. 249, 203). Diacetyl Osotetrazone (formula above),
m.p. 169° with decomposition. Diacetyl Osotriazone (formula above), m.p. 35°,
b.p. 255° (B. 21, 2759). Acetyl Propionyl Osazone, m.p. 162° (B. 21, 1414 ;
A. 247, 221).
The i,3-diketones and the i,3-hydroxymethylene ketones (p. 343) unite
with hydrazine and phenylhydrazine, forming pyrazoles (Vol. II.), which maybe
regarded as derivatives of the i,3-olefine ketols (A. 279, 237) : e.g. hydroxy-
y?CH NH
methylene acetone and hydrazine yield 3-Methyl Pyrazole, CH^
C(CH8):N
(B. 27, 954).
Acetonyl acetone, a i,4-diketone, and phenylhydrazine yield: AcetonylAceto-
CH:C(CH3K
nosazone, m.p. 120°, and Phenylamido-Dimethyl-Pyrrole, \ \N.NHCaH5,
CH:C(CH8K
m.p. 90°, b.p. 270° (B. 18, 60 ; 22, 170).
a-Hydrazoximes. — Methyl Glyoxal Phenylhydrazoxime, CH8.C:N(NHC6H5).-
CH : NOH, m.p. 134°, is prepared by the action of phenylhydrazine on iso-
nitroso-acetoacetic acid. It parts readily with water and becomes methyl n-
CH8C=N,
phenylosotriazole, | ^NCSH» ; (Vol. II.) (A. 262, 278).
CH=N
7. ALCOHOL- or HYDROXY- ACIDS,
Acids of this series show a twofold character in their entire
behaviour. Since they contain a carboxyl group, they are monobasic
acids with all the attaching properties and reactions of the latter ;
the OH-group linked to the radical bestows upon them all the pro-
perties of the monohydric alcohols. As already indicated in the intro-
duction to the dihydric compounds, these alcohols must be distinguished
as primary, secondary, and tertiary, according as they contain, in
addition to the carboxyl group, the group — CH2OH, characteristic
of primary alcohols, the radical =CHOH, peculiar to the secondary
alcohols, or the tertiary alcohol group =C.OH. This difference mani-
fests itself in the behaviour of these bodies when subjected to oxidation.
ALCOHOL- OR HYDROXY-ACIDS 357
However, the manner in which the alcoholic hydroxyl group in an
alcohol-acid acts on the carboxyl group present in the same mole-
cule depends greatly on the position of these two groups with refer-
ence to each other. It is just this differentiating, opposing position
of the two reactive groups which induces class differences of a distinctly
new type, which are therefore made prominent because the oxidations
undergone by primary, secondary and tertiary alcohols are already
known to us. At present they are mostly termed hydroxy-fatty acids,
because of their origin from the fatty acids by the replacement of a
hydrogen atom by OH.
The " Geneva names " are formed by the insertion of the syllable " ol,"
characteristic of alcohols, between the name of the hydrocarbon and the word
"acid "; CH2OH.COOH, hydroxyacetic acid, or [ethanol acid].
Gly collie and ordinary or lactic acid of fermentation are the best-
known and most important representatives.
General Methods of Formation. — (i) Careful oxidation (a) of di-
primary, primary-secondary and primary-tertiary glycols with dilute
nitric acid, or platinum sponge and air :
CH2.OH CHj.OH CH8CH.OH CHSCH.OH
+02=| +H20; | +0a= | +HaO.
CH2.OH COOH CH2OH COOH
Glycol. Glycollic Acid. a-Propylene Glyco o-Lactic Acid.
(b) By the oxidation of hydroxyaldehydes.
(2) The action of nascent hydrogen (sodium amalgam, zinc and
hydrochloric or sulphuric acid, sodium and alcohol, or electrolysis)
on the aldehyde acids, the ketonic acids, and dicarboxylic acids.
Pyroracemic Acid, CH3.CO.CO2H+2H=CH3.CH(OH).CO2H.
Oxalic Acid, COOH.COOH+4H=COOH.CH2OH+H2O.
This reaction has been repeatedly used in preparing j8-, y- and
8-hydroxy-acids from j3-, y- and 8-ketone carboxylic esters.
(3) Some fatty acids have OH directly introduced into them.
This is accomplished by oxidizing them with KMnO4 in alkaline
solution.
Only acids containing the tertiary group CH (a so-called tertiary H-atom) are
adapted to this kind of reaction (R. Meyer, B. 11, 1283, 1787 ; 12, 2238 ;
A. 208, 60 ; 220, 56). Nitric acid effects the same as KMnO4 (B. 14, 1782 ;
16, 2318).
(4) By heating unsaturated fatty acids with aqueous potassium
or sodium hydroxide to 100° (A. 283, 50).
(5) By the reaction of the monohalogen fatty acids with silver
oxide, boiling alkalis, or even water. The conditions of the reaction
are perfectly similar to those observed in the conversion of the
alkylogens into alcohols.
CH2C1C02H+H2O=CH2(OH)COOH+HC1.
The a-derivatives yield a-hydroxy-acids ; the ^-derivatives are occasionally
changed to unsaturated acids by the splitting-off of a halogen acid, whilst the
y-compounds form y-hydroxy- acids, which subsequently pass into lactones.
y- Halogen acids are converted directly into lactones by the alkali carbonates.
358 ORGANIC CHEMISTRY
(6) By the action of nitrous acid on amido-acids :
CH2(NH2).C02H+HN02=CH2(OH).C02H+N2+H20.
Aminoacetic Acid. Hydroxyacetic Acid.
(7) The hydroxy-acids can be obtained from the diazo-fatty acids,
on boiling them with water or dilute acids.
(8) From the a-ketone-alcohols— e.g. butyroin and isovaleroin
(p. 342) — on treating them with alkalis and air.
Nucleus-synthetic Methods of Formation— (9) By allowing hydro-
cyanic acid and hydrochloric acid to act on the aldehydes and
ketones. At first hydroxy cyanides, the nitriles of hydroxy-acids
(q.v.), are produced after which hydrochloric acid changes the cyanogen
group into carboxyl :
1. Phase: CH,.CHO+HNC=CH8.CH<Q^
2. Phase : CH,.CH<^+2H2O=CH8.CH<^H+NHt.
o-Hydroxypropionic Acid.
In preparing the hydroxycyanides, tKe aldehydes or ketones are treated with
pure hydrocyanic acid, or powdered potassium cyanide may be added to the
ethereal solution of the ketone, followed by the gradual addition of concentrated
hydrochloric acid (B. 14, 1965 ; 15, 2318). The concentrated hydrochloric acid
changes the cyanides to acids, the amides of the acids being at first formed in the
cold, but on boiling with more dilute acid they undergo further change to acids.
Sometimes the change occurs more readily by heating with a little dilute sulphuric
acid. Ethylene oxide behaves like acetaldehyde with hydrocyanic acid.
(10) The glycol chlorhydrins (p. 319) undergo a similar alteration
through the action of potassium cyanide and acids :
1. Phase: CH2(OH).CH2C1+KNC =CH2(OH)CH2.CN-f KC1,
2. Phase: CH1(OH).CH>CN+2H2O=CH2(OH).CH2.CO2H+NH,.
p-Hydroxypropionic Acid.
(n) A method of ready applicability in the synthesis of «-hydroxy-
acids consists in acting on diethyl oxalic ester with zinc and alkyl
iodides (Frankland and Duppa). This reaction is like that in the
formation of tertiary alcohols from the acid chlorides by means of
zinc ethyl, or of the secondary alcohols from formic esters (p. 106)
— i and 2 alkyl groups are introduced into one carboxyl group (A.
185, 184) :
/O.CaH6 Zn(CH3)a /O.CtH5 Zn(CH3)a
c£ — — >c^cn9 -
| ^O I X).ZnCHa I XXZnCH, I X)H
C02C2H5 CO,CtH6 CO.CjH. CO2C2H6
Oxalic Ester. Dimethyl Oxalic
If we employ two alkyl iodides, two different alkyls may be intro-
duced.
The acids obtained, as indicated, are named in accordance with their deriva-
tion from oxalic acid, but it would be more correct to view them as derivatives of
hydroxyaceticacid or glycollic acid, CH2(OH).CO2H, and designate, e.g. dimethyl
oxalic acid, as dimethyl hydroxyacetic acid.
(i2a) ^-Hydroxy-acids are formed when aldehydes or ketones are condensed
*™,a;ralo$en fatty acid esters by means of zinc or magnesium ; e.g. propionic
aldehyde and o-bromopropionic ester yield o-methyl j8-ethyl hydracrylic acid,
ALCOHOL- OR HYDROXY-ACIDS 359
CSH6CH(OH)CH(CH3)COOH ; trioxymethylene, o-bromisobutyric ester and
zinc yield aa-dimethyl hydracrylic acid (comp. p. 287) (C. 1901, I. 1196;
II. 30 ; 1902, I. 856).
(izb) Ketone acid esters and magnesium alkyl iodides produce, in part,
tertiary hydroxy-acid esters ; also, ethyl chloroglyoxylate with magnesium
alkyl halides yields the oxalic ether of the a-hydroxy-acid ester (C. 1902, II. 1359 ;
1900, II. mo):
CH3COC02C2H5+CH,MgI = (CH3)2C(OMgI)COaC2H6
2C2H6OCO.COCl+2CHtMgI=CjH6OCO.C(CH3)aO.CO.CO,C2H6+2MgClI.
(13) When sodium or sodium ethoxide acts on the acetic esters and pro-
pionic esters it converts them into j8-ketone-carboxylic esters, but in the case of
butyric and isobutyric esters it produces the ether esters of 0-hydroxy-acids, such
as ethoxycaprylic ester, (CH,)aCH.CH(OCaH6).C(CH,),COtC2H6, from isobutyric
ester (A. 249, 54).
Cleavage-Reactions. — (14) The fatty acids are formed from alkyl malonic
acids, CRR'(COaR)t, by the withdrawal of a carboxyl group (p. 253), and the
hydroxy-fatty acids are obtained in a similar manner from alkyl hydroxymalonic
acids or tartronic acids :
CR(OH)<£°a^=CRH(OH).C02H+COa.
Alkyl Tartronic Acid. Alkyl Hydroxyacetic Acid.
Isomerism. — The possible cases of isomerism with the hydroxy-
acids are most simply deduced by considering the hydroxy-acids as
the mono-hydroxyl substitution products of the fatty acids. Then
the isomers are the same as the mono-halogen fatty acids, which
may be regarded as the haloid esters of the alcoholic acids corresponding
with them.
Hydroxyacetic or glycollic acid is the only acid which can be obtained from
acetic acid :
CH8.COOH CH,OH.COOH
Acetic Acid. Glycollic Acid (p. 363).
Propionic acid yields two hydroxypropionic acids :
CH3CH2.CO9H CH3CH(OH).COOH CH2(OH)CH?.COOH
Propionic Acid. «-Hydroxypropionic Acid /3-Hydroxypropionic Acid
ord. Lactic Acid (p. 362). Hydracrylic Acid (p. 369).
These are distinguished as o- and j3-hydroxypropionic acids respectively.
The a-acid contains an asymmetric carbon atom, and therefore, theoretically,
should yield an inactive variety, which can be resolved, and two optically active
modifications : these, in fact, exist.
Normal butyric acid yields three and isobutyric acid two mono-carboxylic
acids :
TH PW TW TO IT (CH,.CHS.CH(OH).CO2H a-Hydroxybutyric Acid (p. 365)
,H,.CH,.CH2COari ;cH3.CH(OH).CHa.CO3H j8-Hydroxybutyric Acid (p. 370)
(CHa(OH).CHt.CH2.COOH y-Hydroxybutyric Acid (p. 374)
™'>C(°H)-C°2H • • a-Hydroxyisobutyric Acid
£H8 (p 365)
Iso-butyric Acid. HOCH >CH'CO*H ' ' ' 0-Hvdroxyisobutvric Acid (on-
known).
These alcohol-acids are divided into —
Primary acids : Glycollic acid, hydracrylic acid, y-hydroxybutyric acid, /?-hydroxy-
isobutyric acid.
Secondary acids : a-hydroxypropionic acid, a-hydroxybutyric acid, /Miydroxy
butyric acid.
Tertiary acids : a-Hydroxyisobutyric acid.
36o ORGANIC CHEMISTRY
Properties— The hydroxy-fatty acids containing one OH group are,
in consequence, more readily soluble in water, and less soluble in ether
than the parent acids (p. 251). They are less volatile and, as a general
rule, cannot be distilled without decomposition.
Reactions. — (i) The alcohol-acids behave like the monocarboxylic
acids, in that they yield, through a change in the carboxyl group,
normal salts, esters, amides, and nitriles :
COOK COOCaH, CONH, CN
CH2OH CH2OH CH2OH CHaOH.
(2) The remaining OH-group behaves like that of the alcohols,
of which the hydrogen may be replaced by alkali metals and alkyls ;
by acid radicals such as NO2, by the action of a mixture of con-
centrated nitric and sulphuric acids ; or by a carboxylic acid residue,
by the action of acid chlorides and anhydrides, such as the acetyl
residue by means of acetyl chloride and anyhdride,
CH,.CHONO, CH3.CHOCOCHt
COOH COOH.
Nitrolactic Acid. Acetyl Lactic Acid.
Both of these reactions are characteristic of the hydroxyl groups of
the alcohols (p. 323).
(3) PC16 replaces the two hydroxyl groups by chlorine :
COOH PCI, COC1
| + =| +2POC1.+2HCL
CHaOH PC16 CHaCl
Glycollic Chloracctyl
Acid. Chloride.
The acid chlorides corresponding with the hydroxy-acids are not
known. Instead of these we get the chlorides of the corresponding
monochloro-fatty acids, in which the chlorine in union with CO is very
reactive with water and alcohols, yielding free acids and their esters ;
in the case cited, monochloracetic acid, CH2C1.CO2H, and its esters
result. The remaining chlorine atom is, on the contrary, more firmly
united, as in chlorethane.
In addition to ethyl glycollic ester there are ethyl glycollic acid and
ethyl etho-glycollic ester :
COOC2H5 COOH COOC2H,
CH2.OH CHa.OC2H5 CH2OC2H5.
Ethyl Glycollic Ethyl Glycollic Ethyl Etho-glycollic
Ester. Acid. Ester.
Alkalis cause the alkyl combined with CO2 to separate, forming
etL/1 glycollic acid.
(4) The hydroxy-acids are reduced to their corresponding fatty
acids (p. 252) when they are heated with hydriodic acid.
(5) Whilst in the preceding transpositions all the hydroxy-acids
react similarly, the primary, secondary and tertiary alcohol-acids
show marked differences when they are oxidized.
STRUCTURE OF NORMAL CARBON CHAINS 361
(a) The primary hydroxy-acids yield, by oxidation, aldehyde
acids :
C02H C02H COOH
CH2OH CHO COOH.
Glycollic Acid. Glyoxylic Acid. Oxalic Acid.
(b) The secondary hydroxy-acids yield ketone acids : the a-ketonic
acids change to aldehyde and C02, the j3-ketonic acids to ketones
and CO2 :
C02H C02H CO,
CH8CHOH CH8CO . CH8CHO.
(c) Tertiary a-hydroxy-acids yield ketones :
(6) The a-hydroxy-acids undergo a similar decomposition when heated with
dilute sulphuric or hydrochloric acid or by action of concentrated H2SO4. Their
carboxyl group is removed as formic acid (when concentrated H,SO4 is employed,
CO and H2O are the products) :
(CH3)2C(OH)COaH = (CH3)2CO+HC02H
CH8CH(OH)C02H=CH3.CHO+HC02H.
Another alteration is undergone by the a-hydroxy-acids at the same time,
which, however, does not extend far : water is eliminated, and unsaturated acids
are produced. This change is easily effected when PC13 is allowed to act on the
esters of a-hydroxy-acids (p. 291).
(7) Especially interesting is the behaviour of the a-, /?-, y-, or 8-hydroxy-
acids in respect to the elimination of water from carboxyl and alcoholic hydroxyl
groups.
(a) The a-hydroxy-acids lose water when they are heated and become cyclic
double esters — the lactides — in the formation of which two molecules of the
o-hydroxy-acid have taken part :
COOH HO.CH.CH, CO.O.CH.CH8
I + I =11 +2H20.
CH3CHOH HOCO CH3CHO-CO
o-Hydroxypropionic Acid or Lactic Acid. Lactide.
(b) When the ^-hydroxy-acids are heated alone, water is withdrawn and un-
saturated acids are the products (p. 291 ; C. 1897, I. 363) :
CH2(OH).CH2C02H = CH2 : CHCOaH+HtO.
/3-Hydroxypropionic Acid Acrylic Acid.
Hydracrylic Acid.
(c) The y- and ^-hydroxy-acids lose water at the ordinary tempera-
ture, and change more or less completely into simple cyclic esters — the
y- and 8-lactones.
The a-, /?-, y- and 8-amido-carboxylic acids corresponding with the a-, j8-, y-
and 8 -hydroxy-acids, show differences similar to those manifested by the latter.
STRUCTURE OF NORMAL CARBON CHAINS AND THE FORMATION OF
»LACTONES
The peculiar differences in the behaviour of the a-, j8-, y- and 8-hydroxy-acids
when they split off water have contributed to the development of a representation
oi the spacial arrangement or configuration of carbon chains (B. 15, 630). The
362 ORGANIC CHEMISTRY
assumption that the atom 5 of a molecule not linked to each other in a formula can
exert an affinity upon one another has led to the idea that, in a union of more
than two C atoms, these atoms arrange themselves not in a straight line, but
upon a curve. We can then comprehend that cyclic, simple ester formation can
not take place between the first and second carbon atoms, rarely between the
second and third, but readily between the first and fourth or first and fifth carbon
atoms, which have approached so near to each other that an oxygen atom
is capable of bringing about a closed ring (see Alkylene Oxide, p. 317, and
Alkylene Imines, p. 334, as well as the strain theory of v. Baeyer in the introduction
to the carbocyclic derivatives, Vol. II.).
A. SATURATED HYDROXYMONO-CARBOXYLIC ACIDS, HYDROXY-
PARAFFIN MONOCARBOXYLIC ACIDS
a-Hydroxy- acids.
(1) Gly collie Acid, Hydroxyacetic Acid [Ethanol Acid], CH2.OH.-
COOH, m.p. 80°, occurs in unripe grapes and in the green leaves of
Virginia creeper, Ampelopsis hederacea.
History. — Glycollic acid was first obtained in 1848 by Strecker from amino-
acetic acid or glycocoll — hence the name — according to the sixth method of
formation (p. 358). In 1856 Debus discovered it together with glyoxal and
glyoxylic acid among the oxidation products obtained from ethyl alcohol by the
action of nitric acid. Wtirtz in 1857 observed its formation in the oxidation of
etkylene glycol, and KekuU in 1858 showed how it could be made by boiling a
solution of potassium chloracetate (A. 105, 286 ; comp. B. 16, 2414 ; A. 200,
75; B. 26, R. 606).
It is also produced by the action of potassium hydroxide on glyoxal
(p. 346) ; by the reduction of oxalic acid method of formation (No. 2,
p. 357), and from diazoacetic ester (method of formation No. 7). Its
nitrile results when hydrocyanic acid acts on formaldehyde (method No.
9), and is converted by hydrochloric acid into glycollic acid. It is also
formed with hexamethylene tetramine when formaldehyde is warmed
with KNC (C. 1900, I. 402). It also appears in the oxidation ol
glycerol and dextrose by silver oxide.
Glycollic acid crystallizes from acetone. It is very soluble in water
and alcohol. Diglycollide and polyglycollide (p. 367) are produced
when it is heated. Nitric acid oxidizes it to oxalic acid. When heated
with concentrated sulphuric acid, glycollic acid decomposes into
trioxymethylene (metaformaldehyde, p. 199), carbon monoxide and
water).
Calcium Salt, (CH2OHCO2) 2Ca -f 3H2O ; ethyl ester, CH2OH.C02C2H5,
b.p. 160°.
Trichlorethyl alcohol (p. 117) can be regarded as being the
chloride of orthoglycollic acid.
(2) Lactic Acid of Fermentation, a-Hydroxypropionic Acid, Ethyli-
dene Lactic Acid, [d+l] Lactic Acid [2-PropanolAcid],CH3CH(OH)CO2H,
m.p. 18°, b.p.12 120° (B. 28, 2597), is isomeric with p-hydroxypropionic
acid, hydracrylic acid, Opropanol acid], CH2OH.CH2CO2H, which
will be discussed later as the first jS-hydroxy-acid.
Lactic Acid is formed by a special fermentation, the lactic acid
fermentation of lactose, sucrose, gum and starch. It is, therefore,
contained in many substances which have soured — e.g. in sour milk,
LACTIC ACID OF FERMENTATION 363
in sauerkraut, pickled cucumbers, common (or lesser) centaury
(Erythroca centaurium), also in the gastric juice.
Methods of Formation. — The acid is artificially prepared by the
methods already described : (i) from a-propylene glycol ; (2) from
pyroracemic acid ; (5) from a-chloro- or bromo-propionic acid ;
(6) from alanine ; (9) from acetaldehyde and hydrocyanic acid ;
(13) by heating isomalic acid, CH3C(OH)(COOH)2 (B. 26, R. 7).
Other methods of formation are : the action of heat on dextrose or sucrose
with water and 2-3 parts of barium hydroxide at 160° ; prolonged contact of
hexoses with dilute sodium hydroxide solution (B. 41, 1009) ; the interaction of
pentoses, such as arabinose and xylose with warm potassium hydroxide solution
(B. 35, 669) ; heating a-dichloracetone, CH8.CO.CHC12, with water at 200°, and
oxidation of acetol (p. 341), all depend on the transformation of pyroracemic
aldehyde.
Lactic Acid Fermentation. — This fermentation is induced in sugar solutions
by a particular ferment, the lactic acid bacillus, Bacillus acidi lacti, which is
present in decaying cheese. It proceeds most rapidly at temperatures ranging
from 35° to 45° (C. 1897, II. 338). It is noteworthy that the bacillus is very sensitive
to free acid. The fermentation is arrested when sufficient lactic acid is produced,
but is again renewed when the acid is neutralized. Therefore, zinc or calcium
carbonate (C. 1897, II. 20, 937) is added at the beginning, and the lactic acid
thus obtained either as the calcium or zinc salt. Should the fermentation con-
tinue for some time, the lactic will pass into butyric fermentation, the insoluble
calcium lactate will disappear, and the solution will at last contain calcium
butyrate (comp. n-Butyric Acid, p. 259). On the formation of lactic acid as
an intermediate product in the fermentation of dextrose to alcohol and COa, see
B. 37, 421 ; A. 349, 125.
History. — Scheele (1780) discovered lactic acid in sour milk. In 1847 Liebig
demonstrated that the sarcolactic acid found by Berzelius (1808) in the fluids of
the muscles was different from the lactic acid of fermentation. Wurtz (1858)
described the formation of fermentation lactic acid from a-propylene glycol and
air in the presence of platinum black, and recognized that it was a dibasic acid.
Kolbe (1859) obtained lactyl chloride by the action of PC16 on calcium lactate.
This body is identical with chloropropionyl chloride, and lactic acid is therefore
monobasic and must be considered as hydroxypropionic acid. Later (1860)
Wurtz called it a diatomic, monobasic acid, meaning to indicate thereby that one
of the two typical hydrogen atoms is more basic than the other. " But it is much
more significant when KekuU declares that it is simultaneously an acid and an
alcohol " (B. 20, R. 948). Strecker was the first to synthesize the acid from
synthetic amidolactic acid or alanine, which had also been prepared by him
through the interaction of hydrazonic acid and aldehyde ammonia.
Fermentation lactic acid is a syrup soluble in water, alcohol and
ether, and is optically inactive (C. 1905, II. 1527). Placed in a desic-
cator over sulphuric acid, it partially decomposes into water and its
anhydride. When distilled it yields lactide (p. 367), aldehyde, carbon
monoxide and water.
Heated to 130° with dilute sulphuric acid, it decomposes into alde-
hyde and formic acid ; when oxidized with KMnO4, it yields pyro-
racemic acid ; whilst with chromic acid, acetic acid and carbon dioxide
are formed. Heated with hydrobromic acid, it changes to a-bromo-
propionic acid.
Hydriodic acid at once reduces it to propionic acid, and PC15
changes it into chloropropionyl chloride (p. 360).
Lactates. — The sodium salt, CH8CH(OH)CO,Na, is an amorphous mass. When
heated with metallic sodium, disodium compound, CH3CH(ONa)CO2Na, results ;
* 'urn salt, (CaH,O8)aCa+5H,O, is soluble in ten parts of cold water, and ia
calci
364 ORGANIC CHEMISTRY
very readily dissolved by hot water; zinc salt, (C3H5O3)2Zn+3H2Ol dissolves in
58 parts of cold and 6 parts of hot water; iron salt, (C3H6O3)2Fe+3H2O.
The chloride of ortholactic acid, CH3CH(OH)CC13, m.p. 50°, b.p. 161°,
has already (p. 118) been referred to as trichlorisopropyl alcohol. It
is also obtained from chloral by means of methyl magnesium iodide,
and constitutes the soporific Isopral. With sodium ethoxide it forms
ethyl a-ethyl lactate (p. 366) (C. 1904, I. 636 ; 1905, I. 344 ; B. 40,
212).
The Optically Active Lactic Acids.
The optically inactive, fermentation lactic acid contains an asym-
metric carbon atom indicated in the formula CH3.CH(OH)C02H by
the small star. The acid can be resolved by strichnine, morphine,
or quinine, into two optically active components, — dextro-lactic (d-)
acid and laevo-lactic (/-) acid, — possessing similar but opposite rotary
power. The strychnine salt of the Isevo-acid crystallizes out first,
whilst the quinine salt of the dextro-acid is obtained first (B. 24, R.
794 ; C. 1906, I. 1150 ; II. 499).
It must be noticed again here, that those optically inactive compounds
which can be split into two optically active isomers or can be formed from
these, are referred to as racemic [d+\~\ modifications (comp. p. 56).
On mixing solutions of equal quantities of laevo- and dextro-lactate
of zinc, the zinc salt of fermentation lactic acid will be produced, and,
being more insoluble, will crystallize out. The dextro-modification
will remain, if Penicillium glaucum is permitted to grow in the solution
of inactive ammonium lactate (B. 16, 2720), whilst the laevo-rotatory
modification is produced in the breaking down of a sucrose solution
by Bacillus acidi Icevolactici (B. 24, R. 150).
The active lactic acids are connected with the active a-bromo-
propionic acids (p. 288) in the following manner : df-bromopropionic
acid with potassium hydroxide solution gives ^-lactic acid ; silver
carbonate, however, produces the /-acid ; the /-bromopropionic acid
behaves vice versa (comp. Walden's Inversion, p. 55 ; and B. 100,
d-Bromopropionic acid - >• <f-Lactic acid
KOH A
. Q
/-Lactic acid - — — >- /-Bromopropionic acid
^-Alanine (^-a-aminopropionic acid, p. 389) yields, with nitrous
acid, ^-lactic acid. This provides a link between ^-lactic acid and
tartaric acid, wherefrom the probable configuration for d- and /-lactic
acid is obtained (comp. also p. 31 ; against this, however, B. 41,
894):
COOH COOH
H H— C-OH
CH, CH,
rf-Lactic Acid. -Lactic Acid.
On ^-alanine, /-serine, ^-glyceric acid, etc., see B. 50, 3718.
Sarcolactic Acid, Dextro-lactic Acid, Paralactic Acid, was dis-
covered in 1808 by Berzelius in the fluid of the muscles, and shown by
HO— C—
HYDROXYVALERIC ACIDS 365
Liebig (1848) to be different from the lactic acid of fermentation. It
is present in different animal organs, and is most conveniently obtained
from Liebig's beef-extract.
Sarcolactic acid is also formed during butyric fermentation (p. 259)
by the granulo-bacillus and other butyric ferments (C. 1900, I. 777).
Dextro- and laevo-lactic acid, m.p. 26° approx., are very
hygroscopic bodies. Alkali converts the /-acid very rapidly into the
[d+l] modification, whilst the ^-acid is changed more slowly (C.
1904, II. 641).
The rotation of an approximately 1-24 per cent, solution of the
crystallized acid in water is ±2-24° (C. 1906, 1. 1150).
The dextro- and laevo-lactates of zinc crystallize with 2 molecules
of water (C8H5O8)zZn4-aH^O. For other salts, see B. 29, R. 899.
Zinc ^-lactate rotates the plane of polarization to the left, whilst the
Mactate rotates it to the right: [a]$=±8'6°.
Homologous a-Hydroxy-aeids. — The homologous a-hydroxy-acids are, from
the very nature of things, either secondary or tertiary alcohol acids. Gly collie
acid is the only primary a-alcohol acid. (a) The secondary alcohol acids are
generally formed (i) from the corresponding a-halogen fatty acids (method 5) ;
(2) nucleus-synthetic, from aldehydes and hydrocyanic acid, and subsequent
saponification of the nitriles of the hydroxy-acids by means of hydrochloric acid
(method 9). (6) The tertiary hydroxy-acids result —
(1) From the oxidation of dialkyl acetic acid (general method 3).
(2) Upon treating a-ketone alcohols with alkalis and air (method 8, p. 358).
(3) By the action of hydrocyanic acid and hydrochloric acid on ketones
(method 9).
(4) When zinc and alkyl iodides react with oxalic ester (method II, p. 358).
(5) From a-ketone-acid esters and magnesium alkyl halides (C. 1902, II. 1359).
Hydroxybutyrie Acids. — Four of the five possible isomers are known; two
of these are a-hydroxy-acids : (i) a-Hydroxybutyric Acid, CH3CH2CH(OH)CO2H,
m.p. 43°, has been resolved by brucine into its optically active components
(B. 28, R. 278, 325, 725). (2) a-Hydroxyisobutyric Acid, Butyl Lactic Acid, Ace-
tonic Acid, Dimethyl Oxalic Acid [2-Methyl-2-propanol Acid], (CH3)2C(OH)COOH,
m.p. 79°, b.p. 212°, is obtained from dimethyl acetic acid, from acetone and
from oxalic ester (see above) ; hence the names acetonic acid and dimethyl
oxalic acid. It is produced when /?-isoamylene glycol is oxidized by nitric acid,
and is obtained from a-bromo- and a-amidobutyric acid as well as from amyl
pyroracemate and CH3MgI, and from acetone chloroform. It occurs in the
urine during acetonuria (C. 1899, II. 63).
Acetone Chloroform, (CH3)2C(OH)CC13, m.p. 91°, b.p. 167°, is obtained by
the union of acetone and chloroform in the presence of alkali hydroxides. It is a
derivative of a-hydroxyisobutyric acid, the chloride of ortho-a-hydroxyisobutyric
acid (p. 235) which stands in the same relation to a-hydroxyisobutyric acid that
chloroform does to formic acid. Aqueous alkalis convert it into a-hydroxyl-
isobutyric acid (Willgerodt, B. 20, 2445 ; 29, R. 908 ; C. 1898, II. 277 ; 1902,
I. 176). It acts as an anaesthetic and an antiseptic.
In the presence of phenols and sodium hydroxide solution, acetone and chloro-
form yield a-phenoxyisobutyric acids, C,HftOC(CH3)2COOH (C. 1916, II. 326).
a-Hydroxyvaleric Acids :
a-Hydroxy-n-valeric Acid, CH3.CH2.CH2.CH(OH).CO2H, m.p. 28-29° (B. 18,
R. 79).
a-Hydroxyisovaleric Acid, (CH3)2.CH.CH(OH).CO2H, m.p. 86°, is prepared
from dimethyl pyroracemic acid (p. 408) (A. 205, 28 ; B. 28, 296; C. 1902, I. 251).
Methyl Ethyl Glycottic Acid, CC**3>C(OH).CO2H, m.p. 68° (A. 204, 18).
a-HydrpxyeaproiC Acids, a-Hydroxy-n-caproic Acid, CH3[CH2]3CH(OH)COOH,
m.p. 61°, is prepared from a-bromo- or a-amino-n-caproic acid. a-Hydroxy-iso-
366 ORGANIC CHEMISTRY
caproic Acid, Leucic Acid, (CH3)2CH.CHaCH(OH)COOH, m.p. 73°, is obtained.
63° fc/xl&S, I. 202).5° ™-Hydroxy-tert.-butyl Acetic Acid, (CH;j,C.CH(OH)COOH,
m p. 87°, is obtained from trimethyl pyroracemic acid (p. 408) by reduction.
Higher a-Hydroxy-fatty Acids: fl-Diethyl Ethylidene Lactic Acid, (C2H5)2-
CH CH(OH)COOH, m.p. 82°, is prepared from y-bromo-y-acetoxy-a-diethyl
acetoacetic ester, (CaH5)2C(COOR)CO.CHBr(OCOCHs), by means of the cleaving
influence of dilute sulphuric acid (B. 31, 2953). a-Hydroxy-n-caprylic Acid,
CH8[CH2]6CH(OH)COOH, m.p. 69-5°, is obtained from cenanthol. Di-n-propyl
Glycottic Acid.a-Hydroxy-di-n-propyl Acetic Acid, (C3H7)2C(OH)COOH, m.p. 72°,
is prepared from butyroiin (p. 342) (B. 23, 1273). Di-isopropyl Oxalic Acid,
a-Hydroxy-di-isopropyl Acetic Acid, (C8H7)C(OH)COOH, m.p. 111° (B. 28,2463).
Di-isobutyl Glycollic Acid (C4H9)2C(OH)COOH, m.p. 114°. Methyl Nonyl Glycollic
Acid, (C9H19)C(CH3)(CH)COQH, m.p. 46°, is obtained from methyl nonyl
ketone (C. 1902, I. 744).
a-Bromo -fatty acids have yielded the following: a-Hydroxylauric Acid,
C18H22(OH)COOH, m.p. 74° (C. 1904, I. 261) ; a-Hydroxymyristic Acid, C]3H26-
(OH).COaH, m.p. 51° (B. 22, 1747) ; a-Hydroxy palmitic ^c^,C15H80(OH)CO2H,
m.p. 82° (B. 24, 939); a-Hydroxystearic Acid, C17H31(OH)CO2H, m.p. 85°
(B. 24, 2388).
In the following pages those a-hydroxy-acid derivatives will be described
which belong to glycollic and lactic acids.
Alkyl Derivatives of the a-Hydroxy-aeids.
A single a-hydroxy-acid yields three kinds of alkyl derivatives : ethers, esters
and ether-esters :
COOH COOH COOC2HS COOC2H6
CH2OH CH2OC2H? CH2OH CH2OC2H5.
Acid. Acid. Ester. Ethyl Ester.
(1) The alkyl-ethers of the a-hydroxy-acids are obtained (i) by the action of
sodium alcoholates on salts of the a-halogen substitution products of the fatty
acids ; (2) by the saponification of the dialkyl ether esters or alkyl ether nitriles
(p. 380) of the a-hydroxy-acids.
Methyl-ether Glycollic Acid, CH3OCH2.COOH, b.p. 198°. Ethyl Glycollic
Acid, b.p. 206-207°; chloride, b.p. 128° (J. pr. Ch. [2] 65, 479 ; C. 1907, I. 871).
a-Ethoxyl Propionic Acid, CH3CH(OC2H6).CO2H, b.p. with partial decomposition
195-198°. It is split up by means of cinchonidine or morphine into its two
optical components, which are remarkable for their large rotations.
(2) Alkyl Esters of the a-hydroxy-acids result (i) on heating the free acids
with absolute alcohol ; (2) when the cyclic double esters, the lactides, are heated
with alcohols. Glycollic Methyl Ester, CH2(OH)COOCH3, b.p. 151°. Glycollic
Ethyl Ester, b.p. 160°. Lactic Methyl Ester, CH3CH(OH)CO2CH3, b.p. 145°.
Lactic Ethyl Ester, b.p. 154-5°.
(3) The dialkyl-ethyl esters of the a-hydroxy-acids are produced (i) when
sodium alcoholates act on the esters of a-halogen fatty acids ; (2) by the
interaction of alkylogens and the sodium derivatives of the alkyl esters of the
a-hydroxy-acids.
Methyl Glycollic Methyl Ester, CH2(OCH3).COOCH8, b.p. 127°; ethyl ester,
b.p. 131°. Ethyl Glycollic Methyl Ester, CH2(O.C2H$)CO.OCH3, b.p. 148°.
Ethyl Glycollic Ethyl Ester, b.p. 152° (B. 17, 486). Methyl Lactic Methyl Ester,
CH,CH(OCH3)COOCH3, b.p. 135-138°; ethyl ester, b.p. 135-5°. Ethyl Lactic
Ethyl Ester, CHS.CH(OC2H5).COOC2H8, b.p. 155° (A. 197, 21 ; B. 40, 212).
Anhydride Formation of the a-Hydroxy-Acids.
Since the a-alcohol-acids possess the characteristics of both car-
boxylic acids and alcohols, they are capable of forming various types
of anhydrides. These may occur between the alcoholic groups of two
molecules (dicarboxylated ethers or ether acids), between the carboxylic
ANHYDRIDES. LACTIDES 367
groups, between the alcoholic groups (dihydroxylated carboxylic
anhydrides and ether carboxylic anhydrides], and, finally, between the
alcohol group of one molecule and the carboxylic group of a second
(alcohol ester acids or semilactides and cyclic double esters or lactides].
The best example for examination is glycollic acid.
r- °<CH2COOH Alcoho1 anhydride of glycollic acid : Diglycollic Acid.
2t HOCH2CO>° G1ycoUic anhydride is not known.
3. O<p52 r(>>O Alcohol- and acid-anhydride of glycollic acid : Diglycollic
2 Anhydride.
4- HOCOCH>° Open ester acid : Glycollo-glycollic Acid.
5- O<£££?>O Closed, cyclic double ester of glycollic acid: Gly 'collide,
simplest Lactide.
Diglycollic Acid, the alcohol anhydride of glycollic acid, C4H8O5, is formed
together with glycollic acid on boiling monochloracetic acid with lime, baryta,
magnesia, or lead oxide, and hi the oxidation of diethylene glycol,
(p. 313). Diglycollic acid crystallizes with water in large rhombic prisms.
Diglycollic Anhydride, O<cH2CO^°' m'p* 97°' b>p> 24°°' is isomeric witn
glycollide. It is obtained from glycollic acid by a simultaneous alcohol-anhydride
and acid-anhydride formation. It also results upon heating diglycollic acid, or
by boiling it with acetyl chloride (A. 273, 64).
Dilactylic Acid, O(CH8CHCOOH)2, has received little attention.
Glycolloglycollic Acid, CH2(OH)COOCH2COOH, generally termed glycollic
anhydride, and Lactylolactic Acid, CH3CH(OH)COOCH(CH3)COOH, commonly
called lactic anhydride, have not been well studied. They are produced when
the free a-hydroxy-acids are heated to 100°, and constitute intermediate steps in
the lactide formation (B. 23, R. 325). Distillation of lactic acid produces
lactyl lactic acid, lactide, and also Lactyl Acetyl Lactic Acid, CH8CH(OH)COOCH-
(CH3)COOCH(CH8)COOH, m.p. 39°, b.p. 235-240° (C. 1905, I. 862).
Lactides : Cyclic Double Esters of the a-Hydroxy-acids.
Diglycollide, O<™>O, m.p. 86°, is produced when polyglycollide is
distilled under greatly reduced pressure. When heated at the ordinary pressure,
or if kept, it reverts to polyglycollide, from which it differs by its lower
melting point and ready solubility in chloroform. It combines readily with
water (A. 279, 45).
Polyglycollide, (C2H2O2)x, m.p. 223°, is formed on heating glycollic acid, and
when dry sodium chloracetate is heated alone to 150°. It passes into glycollic
esters when heated with alcohols in sealed tubes (A. 279, 45).
Lactide, °<COCH(CH )>O' m'p' I25°' b-p'760 255°' b>p'18 I38° (B< 28'
2595), results on heating lactic acid under diminished pressure. It can be
recrystallized from chloroform (A. 167, 318; B. 25, 3511 ; 28, 2595). d- and
l-Lactide, m.p. 95° (C. 1906, I. 1329). The optical rotation of the lactic acids is
increased greatly by lactide formation. Homologous lactides, see B. 26, 263 ;
A. 279 100.
COO v
Cyclic Ether Esters. — Glycollic Methylene Ester, \ yCH2, is obtained from
CH2OX
glycollic acid and formaldehyde (C. 1901, II. 1261). Glycollic Ethylene Ester,
COOCH2
| , m.p. 31°, b.p. 214° (B. 27, 2945).
CH2OCHg
COO,
Methylene Lactate, /CH2, b.p. 153° (B. 28, R. 180),
CHgCHO'
368 ORGANIC CHEMISTRY
coov
Lactic Ethylidene Ester, >CH.CH8, b.p. 151°, is produced when
CHgCHCK
lactic acid and acetaldehyde are heated to 160°. Its hexachloro-derivative is
chloralide (below).
Acid Esters of the a-Hydroxy-acids.
Nitrogly collie Acid, m.p. 54°, results, together with nitroglycollyl glycollic acid,
NO2OCHtCOOCH2COOH, from glycollic acid and nitrosulphuric acid.
Nitrolactic Acid, CH3CHO(NOa)COOH, is a yellow liquid, decomposing at the
ordinary temperature into oxalic and hydrocyanic acids (B. 12, 1837 ; C. 1903,
II. 488 ; 1904, 1. 434). Mono-halogen acetic acid (p. 287) and a-halogen propionic
acid (p. 288) are looked on as being haloid acid esters of a-hydroxy-acids.
Acetyl Glycollic Acid, CHaO(COCH3)COOH, m.p. 67°, b.p.12 145°, is obtained
from glycollic acid and acetic anhydrides; chloride, b.p.14 54°; ethyl ester,
CH2O(COCH3)COOCaH5, b.p. 179°. Acetyl Lactic Acid, CH3CH(OCOCH3)-
COOH, m.p. 57-60°, b.p.n 127°, is prepared from lactic acid and acetyl
chloride; chloride, b.p.n 56° (B. 36, 466 ; 37,397!; 88,719; €.1905,1.1373).
Halogen a-Hydroxy-acids.
8-Monohalogen Ethylidene Lactic Acids.— fi-Chlorolactic Acid, CH2C1CH-
(OH)CO2H, m.p. 78°. fi-Bromolactic Acid, CH2BrCHOHCO2H, m.p. 89°.
p-Iodolactic Acid, CH2ICH(OH)CO2H, m.p. 100°. These three acids have been
prepared by adding hydrogen chloride, bromide or iodide to epihydrin or glycidic
acid, CH2CH(O)CO2H.
/J-Chlorolactic acid is also formed from monochloraldehyde by the action of
hydrocyanic acid and by the oxidation of epichlorhydrin, CHaCH(O)CH2Cl, and
a-chlorhydrin, CH2C1CH(OH).CH2OH, with concentrated HNO, ; as well as by
the addition of hypochlorous acid to acrylic acid (together with a-chlorhydra-
crylic acid).
Silver oxide converts it into glyceric acid ; when reduced with hydriodic acid
it becomes jS-iodopropionic acid. Heated with alcoholic potassium hydroxide
it is again changed to epihydric acid (see above), just as ethylene oxide is obtained
from glycol chlorhydrin (p. 317).
Higher halogen substitution products of the a-hydroxy-acids have been
prepared by the progressive treatment of halogen aldehydes, like di-
chloraldehyde, chloral, bromal, and trichlorobutyric aldehyde, with
hydrocyanic acid and hydrochloric acid. Trichlorolactic acid has
been the most thoroughly studied.
B-DichlorolacticAcid, CHCla.CH(OH).COaH, m.p. 77°.
j3-Trichlorolactic Acid, CC13.CH(OH)CO2H, m.p. 105-110°, is
soluble in water, alcohol and ether. Alkalis easily change it into
chloral, chloroform and formic acid. Zinc and hydrochloric acid
reduce it to dichlor- and mono-chloracrylic acids (p. 294).
Because trichlorolactic acid yields chloral without difficulty, it is converted
quite readily, by different reactions, into derivatives of chloral, and also of
glyoxal, probably by decomposition into dichloraldehyde and CO2. It forms
glyoxime with hydroxylamine, and glycosin with ammonia (p. 346, and B. 17,
1997).
. Trichlorolactic Ethyl Ester, CC13CH(OH)COOC2H6, m.p. 66°, b.p. 235°, is
prepared from chloral cyanhydrin with alcohol and sulphuric or hydrochloric
acid (B. 18, 754).
Chloralide, Trichlorethylidene Trichlorolactic Ester, CC13.CH<CQ >CH.CCla,
m.p. 114°, b.p. 272°, was first prepared by heating chloral with fuming sulphuric
acid to 105°, and subsequently when trichlorolactic acid was heated to 150° with
HYDRACRYLIC ACID 369
excess of chloral. When heated to 140° with alcohol, it breaks up into trichloro-
lactic ester and chloral alcoholate (Wallach, A. 193, i). Chloral also unites with
lactic and other hydroxy-acids, glycollic, malic, salicylic, etc., forming compounds
very similar to that with trichlorolactic acid, known as chloralides (A. 193, i).
Tribromolactic Acid, CBr3.CH(OH)CO2H, m.p. 141-143°, unites with chloral
and bromal to corresponding chloralides and bromalides.
Trichlorovalerolactic Acid, CHsCClaCHCl.CH(OH).CO2H, m.p. 140° (A. 179, 99).
j3-Hydroxycarboxylic Acids.
Generally the /Miydroxycarboxylic acids, when heated, part with
water and become converted into unsaturated olefine carboxylic acids :
— H2O
CH2OH.CH2.CO2H - > CH2=CHCO2H.
Ethylene Lactic Acid or Hydracrylic Acid. Acrylic Acid.
In the case of the higher homologues of ethylene lactic acid, when
water is eliminated, both a/3- and j8y-olefine carboxylic acids (B. 26,
2079) result.
a-Dialkyl ^-Hydroxy-acids and their esters are prepared from the
dialkyl acetoacetic esters by reduction, and from aldehydes, a-bromo-
dialkyl acetic esters by zinc. Those which possess no hydrogen
atom in the a-position free to take part in the splitting off of water
decompose in various ways : when heated, some are converted into
a mixture of aldehydes and dialkyl acetic acids ; others yield semi-
lactides, such as the a-hydroxy-acids (p. 366) (C. 1904, I. 1134) :
CH3CH(OH)C(C2H5)2COOH=CH3CHO+CH(C2H5)2C09H
a-Diethyl-/3-hydroxybutyric Acid. Diethyl Acetic Acid.
CH2(OH)C(CH3)2COOH
Hydroxypivalic Acid.
- > CH2(OH)C(CH8)2COO[CH2C(CH3)2COO]4CHa.C(CH3)2COOH
The esters of such acids containing free hydrogen atoms attached
to a carbon atom in the y-position react with P2O5 in a benzene solu-
tion and form jSy-olefine carboxylic acids ; in other cases atomic
wandering occurs, and aj8-olefine carboxylic acids result (pp. 293,
371) (C. 1906, 1. 999 ; II. 318).
jS-Hydroxyacids are produced (i) in the oxidation of primary-secondary and
primary- tertiary glycols ; (2) (p. 357) by the reduction of j8-ketone carboxylio
esters (secondary hydroxy-acids); and (3) on boiling jSy- or A2-olefine carboxylic
acids with sodium hydroxide. Furthermore, zinc and the esters of the mono-
halogen fatty acids — e.g. bromisobutyric ester— combine with aldehydes (isobutyl
aldehyde) to form secondary j3-hydroxy -acids, and with ketones to form tertiary
0-hydroxy-acids (B. 28, 2838, 2842 ; C. 1906, 1. 999 ; II. 318). In these reactions
the following stages can be recognized : —
I. CH2Cl.COaR'+Zn=CHa(ZnCl)COOR'
-
II. CH2(ZnCl)C02R' + (C2H5)aCO
III. /
Ethylene Lactic Acid, Hydracrylic Acid [3-Propanol Acid],
CH2(OH).CH2.CO2H, is isomeric with ethylidene lactic acid or the lactic
acid of fermentation, and is obtained (i) by the oxidation of trimethy-
lene glycol ; (2) from /Modopropionic acid, or j8-chloropropionic acid,
with moist silver oxide ; (3) from acrylic acid by heating with aqueous
VOL. I. 2 B
37o ORGANIC CHEMISTRY
sodium hydroxide to 100° ; (4) by the saponification of ethylene
cyanhydrin with hydrochloric acid. This reaction completes the
synthesis of ethylene lactic acid from ethylene :
CHaCN CHaCOaH
CH2OH ' CH.OH
>CH.(
The free acid forms a non-crystallizable, thick syrup. When
heated alone, or when boiled with sulphuric acid (diluted with I part
H2O), it loses water and forms acrylic acid (hence the name hydra-
crylic acid).
Hydriodic acid again changes it to /Modopropionic acid. It yields
oxalic acid and carbon dioxide when oxidized with chromic acid or
nitric acid.
The sodium salt, CH^OHiCHjCC^Na, m.p. 142-143°, and the calcium salt,
(CtH5O3)2Ca+2HaO, m.p. anhydrous 140-150°, when heated above their melting
points pass into the corresponding acrylates. The zinc salt, (CaHtO3)2Zn-f4HaO,
is soluble in water and alcohol, whereas the latter precipitates zinc salts of
the isomeric acids. fi-Amyloxypropionic Acid, CgHjjOCHjCHjCOOH, b.p.?0
140°, yields the diamyl-ether of tetramethylene glycol, when its sodium salt is
electrolyzed (p. 315) (C. 1905, I. 1698).
0-Hydroxybutyric Acid, [3-Butanol Acid], CH3CH(OH)CHaCOaH, is formed
(i) by the oxidation of aldol (p. 338) ; (2) by the reduction of acetoacetic ester
§' .416) with sodium amalgam ; (3) from a-propylene chlorhydrin, CH3CH(OH)-
3,C1, by the action of KNC and subsequent hydrolysis of the cyanide. It is
a thick oil and is volatile in steam. Heat decomposes it into water and crotonic
acid, CH3.CH : CHCOOH. Conversely, crotonic ester unites with alcohol in
the presence of CaH$ONa to form /J-ethyoxybutyric ester, CaH6O.CH(CH3)CH3-
COaR (B. 33, 3329). The racemic acid is split by means of its quinine salts ; the
/two-rotatory component [a]D=— 24-9° is separated out, and the dextro-rotatory
component is obtained from the mother liquor. An optically active /J-hydroxy-
butyric acid has been isolated from diabetic urine (B. 18, R. 451).
B-Hydroxyi$obutyric Acid, HOCHaCH(CH3).COaH, is not known.
p-Hydroxy-n-valeric Acid, CH3CH2CH(OH).CH8COaH (A. 283, 74, 94).
a-Methyl fi-Hydroxybutyric Acid CH,CH(OH)CH(CH3)CO2H (A. 250, 244).
a-Ethyl Hydracrylic Acid, is a syrup: ethyl ester, b.p.,8 96°, is obtained from
trioxymethylene and o-bromobutyric acid in benzene solution with zinc (C. 1905,
II. 45, 540). p-Hydroxyisovaleric Acid, (CH3)aC(OH)CH2.COaH, results when
isobutyl formic acid is oxidized with KMnO4 (A. 200, 273). a-Dimethyl Hydra-
crylic Acid, Hydroxypivalic Acid, HO.CHaC(CH,)aCOOH, m.p. 124° ; ethyl ester,
b.p.,t 86°, is obtained from trioxymethylene, bromisobutyric ester and zinc
(C. 1902, I. 643). Acetoxypivalic chloride (C. 1908, I. 1531).
p-Hydroxy-n-caproic Acid, CH3CHaCHaCH(OH)CH2CO2H, is formed on
boiling hydrosorbic acid with sodium hydroxide (A. 283, 124). a-Ethyl p-
Hydroxybutyric Acid, CH3CH(OH)CH(CaH,)CO2H (A. 188, 240). a-Methyl B-
Hydroxyvaleric Acid, CH,CH2CH(OH)CH(CHa)CO2H (B. 20, 1321).
p-Hydroxyisocaproic Acid, (CH?)aCHCH(OH)CHaCOaH (B. 29, R. 667).
ftp-Methyl Ethyl Hydracrylic Acid is obtained by oxidation of methyl ethyl
allyl carbinol (C. 1900, I. 1069), a-Methyl p-Ethyl Hydracrylic Acid is a syrup.
a-Methyl a-Ethyl Hydracrylic Acid, m.p. 56*. a-Propyl Hydracrylic Acid is a
syrup. a-Isopropyl Hydracrylic Acid, m.p. 64°. aafi-Trimethyl Hydracrylic
Acid, m.p. 31°, b.p.lf 148°, is obtained as an ester (method of formation, No. 12,
P- 358).
p-Hydroxyisoheptylic Acid, (CH3)aCHCHaCH(OH)CH2CO2H, m.p. 64° (A.
283, 143).
LACTONES 371
fi-Methyl Propyl Ethylene Lactic Acid, (CH8)(C8H7)C(OH)CHaCOaH, is pro-
duced in the oxidation of methyl allyl propyl cardinal (J. pr. Ch. [2] 23, 267).
p-Diethyl Ethylene Lactic Acid, (CaHB)aC(OH)CHaCOaH, results from the
oxidation of diethyl allyl carbinol (J. pr. Ch. [2] 23, 201) (p. 124). a-Methyl
Ethyl p-Hydroxybutyric Acid, CH8CH(OH)C(CH8)(C2H6)COaH (A. 188, 266).
Tetramethyl Ethylene Lactic Acid, (CH3)aC(OH)C(CH8)aCO2H. m.p. 152°, is pre-
pared from acetone bromisobutyric ester and zinc. It yields CO2 and dimethyl
isopropyl carbinol when heated. The ester and PaO6 yield dimethyl isopropenyl
acetic acid (B. 28, 2829 ; C. 1906, I. 909). a-Dimethyl fi-Ethyl Hydt 'acrylic Acid,
C2H6CH(OH)C(CH,)aCOOH, m.p. 103° (C. igoi.I. 1196). B-Hydroxyiso-octylic
Acid, (CH3)2CHCH2CHaCH(OH)CHaC02H, m.p. 36° (A. 283, 287).
a-Methyl Propyl p-Hydroxybutyric Acid, CH,CH(OH)C(CH8)(C8H7)COaH (A.
226, 288). a-Diethyl p-Hydroxybutyric Acid, CH8CH(OH)C(C2H6)aCO2H (A. 201,
65 ; 266, 98). a-Dimethyl p-Isopropyl Ethylene Lactic Acid, (CH8)aCH.CH(OH).-
C(CH3)a.CO2H, m.p. 92° (B. 28, 2843), is obtained also by oxidation of the corre-
sponding glycol (p. 316) or aldol (p. 373) (C. 1902, I. 461).
The y- and 8-Hydroxy-acids and their Cyclic Esters, the y- and
8-Lactones. — The y- and 8-hydroxy-acids are distinguished from the
a- and j3-hydroxy-acids * by the fact mentioned (p. 362) that they
are capable of forming simple cyclic esters, when the carboxyl group
enters into reaction with the alcoholic hydroxyl group. This is a
reaction that is accelerated by mineral acids in the case of the forma-
tion of the ordinary fatty acid esters. The cyclic esters of the y- and
S-hydroxy-acids are called y-Lactones and 8-Lactones. In the first
there is a chain of four, in the second a chain of five carbon atoms
closed by oxygen. They sustain the same relation to the oxides of
the y- and 8-glycols, and to the anhydrides of the y- and 8-dicarboxylic
zcids, that the open carboxylic esters bear to the ethers of the alcohols
md fatty acid anhydrides. Suppose, for example, that a hydrogen
itom has been removed from each methyl group in the formulae of
ithyl ether, acetic ethyl ester and acetic anhydride, and the methylene
•esidues are then joined to each other, we then arrive at the formulae
>f tetramethylene oxide, y-butyrolactone and succinic anhydride.
Che following scheme represents these relations :
CH3.CH2, CH8CO . CH3C(X o
CH3.CH2^U CH3.CH2^U CH3CO^U
Ethyl Ether, Acetic Ethyl Ester. Acetic Anhydride.
CHa.CH,v aCH2CO v CH2CCk
• CH2.CH/ j5CH2CH2y/ CH2C(X
Tetramethylene Oxide. y-Butyrolactone. Succinic Anhydride.
This lactone formation occurs more or less easily, depending upon
he constitution of the y-hydroxy-acids. The very same causes which
ifluence the anhydride formation with saturated and unsaturated
icarboxylic acids (q.v.), exert their power with the y-hydroxy-acids.
t has been seen " that increasing magnitude or number of hydro-
I irbon residues in the carbon chains closed by oxygen favours the in-
• *amolecular splitting-off of water among the y-hydroxy-acids " (B. 24,
J 237). When the y-hydroxy-acids are separated from their salts by
\ lineral acids they break down, especially on waiming, almost
. * The lactone of a /3-hydroxy-acid is exemplified by asym.-dimethyl malic
.ctone (q.v.).
372 ORGANIC CHEMISTRY
immediately into water and lactones. It is only when the latter are
boiled with alkali carbonates that they are converted into salts of the
hydroxy-acids. This is more readily accomplished through the agency
of the alkali hydroxides. The y-lactones are characterized by great
stability, being only partially converted into hydroxy-acids by water,
after protracted boiling, whereas those of the S-variety gradually
absorb water at the ordinary temperature and soon react acid (B.
16, 373).
History. — The first (1873) discovered aliphatic lactone was butyrolactone,
obtained by Saytzeff, who, however, regarded it as the dialdehyde of succinic
acid. Erlenmeyer, Sr. (1880), expressed the opinion that lactones could only
exist when they contained the group C — C — C — COO, which is present, as is well
known, in the anhydrides of succinic acid (B. 13, 305). Almost immediately
afterwards /. Bredt demonstrated that isocaprolactone, from pyroterebic acid,
was in fact a y-lactone (B. 13, 748). Fittig, as the result of a series of excellent
investigations, established the genetic relations of the lactones to the hydroxy-
acids and unsaturated acids, and taught how this class of bodies could be produced
by new methods. E. Fischer has shown that polyhydroxylactones play an
especially important r61e in the synthesis of the various varieties of sugar.
The general methods of formation of the y-hydroxycarboxylic acids
and their cyclic esters — the y-lactones :
(1) By the reduction of the y-ketone carboxylic acids with sodium
amalgam :
CH3CO.CH?CH2COOH+2H=CH3CH(OH).CH2CH2COaH.
Laevulinic Acid. y-Hydroxyvaleric Acid.
(2) From the y-halogen fatty acids : (a) by distillation, when the
lactones are immediately produced :
ClCHaCHaCH2COaH - > CHaCH2CHaCOO+HCl ;
(b) by boiling them with water, or with alkali hydroxides, or carbon-
ates. In the latter case y-lactones are even produced in the cold.
(3) From unsaturated acids in which the double union occurs in
the f$y- or yS-position, that is, from the A2-(£y)- or A8-(yS)- unsaturated
acids :
(a) by distillation ;
(b) by digestion with hydrobromic acid, when an addition and
separation of hydrogen bromide occur ;
(c) by digestion with dilute sulphuric acid (B. 16, 373 ; 18, R. 229 ;
29, 1857) :
CHa=(*HCH2CH2COaH - > CH3CHCH2CH2COO
Allyl Acetic Acid. ' y-Valerolactone.
(4) By the decomposition of y-lactone carboxylic acids into y-lactones
and C02, by distillation, whereby the isomeric unsaturated acids are
also produced (pp. 292, 300) :
Terebic Acid. Isocaprolactone.
By similar reactions lactones can be formed by decomposition of the con-!
densation product of glycol halogenhydrin (p. 319), (a) with sodium aceto-
acetic ester, and (b) sodium malonic ester.
LACTONES 373
(5) Reduction of the derivatives of dicarboxylic acids leads to the formation
of glycols (conformably with method of formation 56, p. 310). Alcohol acids
are formed as intermediate products during reduction ; in the cases of esters,
chlorides, or anhydrides of the succinic and glutaric acid series, reduction with
sodium or aluminium amalgam, or with sodium and alcohol, gives rise to a 5-50
per cent, yield of y- and 8-hydroxy-acids and y- and S-lactones respectively.
CH2— OX CH2— CHa. CH2— CH2OH
>0 - > | >O - > |
CH3— CCK CH2— CO ' CH2— CH2OH
Succinic Anhydride. Butyrolactone. Tetramethylene Glycol.
CH'<£H;^>O — * CH^-^X) — > CH.<gf £gHjg"
Glutaric Anhydride. fi-Valerolactone. Pentamethylene Glycol.
Since it is possible to prepare the half-nitrile of the higher dicarboxylic acids
by means of potassium cyanide, and to convert these again into lactones, these
reactions constitute a method for the synthesis of higher lactones out of the lower
members. Asym.-alkyl succinic acids and asym.-alkyl glutaric acids when
reduced yield in the main the two possible lactones (B. 36, 1200 ; C. 1904, I. 925 ;
1905, II. 755).
Nucleus-synthetic Methods of Formation :
(6) The action of zinc alkyls on the chlorides of dibasic acids, or of
magnesium alkyl halides on y-ketonic acid (C. 1902, II. 1359).
(7) KNC on y-halohydrins, and subsequent saponification of the resulting
nitriles.
Nomenclature. — y-Lactones may be viewed as a-, j8-, and y-alkyl
substitution products of butyrolactone, and may be named accord-
ingly ; thus, y-methyl butyrolactone for valerolactone :
JH2.CH2.CH2COO CH3.(*H.CH2.CH2.COO
The " Geneva names " terminate in " olide " ; thus, butyrolactone
=[Butanolide] ; valerolactone =[i,4-peiit2inolide].
Properties of the y- and S-Lactones. They are usually liquid
bodies, easily soluble in water, alcohol, and ether. They possess a
neutral reaction, and a faintly aromatic odour, and can be distilled
without decomposition. The alkali carbonates precipitate them
from their aqueous solution in the form of oils.
Reactions. — (i) They are partially converted into the corresponding
hydroxy-acids when boiled with water. A state of equilibrium arises
here, which is much influenced by the number of alcohol radicals con-
tained in the y-lactones. (2) The lactones are changed with difficulty
by the alkali carbonates into salts of the corresponding hydroxy-acids
(B. 25, R. 845), whereas the alkali hydroxides and barium hydroxide
solution effect this more readily. (3) Many y-lactones combine with
the halogen acids, forming the corresponding y-halogen fatty acids ;
others do not do this. In the latter the lactone union is easily severed
on allowing hydrochloric or hydrobromic acid to act on the lactones
in the presence of alcohol. Then the alkyl ethers of the corresponding
y-chloro- and y-bromo-fatty acids are formed (B. 16, 513). Lactones
are converted into the esters of hydroxy-acids by heating them with
sulphuric acid in alcoholic solution (B. 33, 860).
(4) The y-lactones unite with ammonia, but there is no separation of water
(P- 378)- Similarly, with hydrazine, which gives characteristic crystalline addition-
products, easily split up into hydrazine and lactone (C. 1905, I. 1221).
374 ORGANIC CHEMISTRY
(5) Sodium and alcohol reduce the lactones to glycols.
(6) Potassium cyanide unites with the formation of potassium salts of the
nitrile-carboxylic acids.
(7) The lactones condense under the influence of sodium and sodium alcoholate
to compounds which give up water when treated with acids to form substances
composed of two lactone residues. When boiled with bases, these bodies are
converted to hydroxycarboxylic acids, which split off carbon dioxide, forming
oxetones (q.v.), derivatives of dioxyketones :
CH8.CH.CH2 ,CH2.CHt -H2O
0—CO * > OCH.CH3
CH2— CH2 /CH,— CH2 -CO2 CH3CH
I >C/ I •< I
CH.CH O X) CH.CH, OHH
y-Lactones.
Butyrolactone [Butanolide], CHa.CH2.CH2.COO, b.p. 206°, has been
obtained (i) by allowing sodium amalgam and glacial acetic acid to act
on succinyl chloride in ethereal solution (A. 171, 261 ; B. 29, 1192) ;
(2) from j3-formyl propionic acid (p. 402) by reduction ; (3) frombutyro-
lactone carboxylic acid (q.v.), by the splitting-off of CO2 (B. 16,
2592) ; (4) by the distillation of y-chlorobutyric acid (B. 19, R. 13) ;
(5) from oxethyl acetoacetic ester (the reaction product of ethylene
chlorhydrin and acetoacetic ester) by decomposing it with barium
hydroxide (B. 18, R. 26) ; (6) by treating y-phenyl hydroxybutyric
acid with hydrobromic acid (B. 29, R. 286).
Lactones, C5H,Oa; y-ValeroIactone, y -Methyl Butyrolactone, [i,4-Pentano-
lide], CH,.CH.CH2.CH2.COO, b.p. 206°, occurs in crude wood vinegar, and may
be prepared (i) by the reduction of laevulinic acid, CHSCO.CH2CH2CO2H (A. 208,
104) ; (2) by boiling allyl acetic acid with dilute sulphuric acid ; (3) when
y-bromovaleric acid is boiled with water; (4) on heating y -hydroxypropyl
malonic lactone to 220° C. (A. 216, 56) ; (5) and in small quantities when methyl
paraconic acid is distilled (A. 255, 25). Dilute nitric acid oxidizes y-valerolactone
to ethylene succinic acid, whilst HI converts it into n- valeric acid.
a-M 'ethyl Butyrolactone, CH2CH2CH(CH,)COO, b.p. 201°, is obtained from
pyrotartaric chloride or anhydride by reduction (B. 28, 10 ; 29, 1194 ; C. 1905,
II. 755).
Lactones: C6H10O2.
Caprolactones. y-Ethyl Butyrolactone, y-n-Caprolactone, [i,4-Hexanolide],
CH8.CH2CHCH2CH2COO, b.p. 220°, is formed by the general methods 2, 3,
and 4. It also appears in the reduction of gluconic acid, metasaccharic acid
and galactonic acid by hydriodic acid (B. 17, 1300 ; 18, 642, 1555).
a-Ethyl Butyrolactone, b.p. 219°, is prepared from ethyl succinic anhydride
and from a-ethyl a-ethoxyacetoacetic ester.
py-Dimethyl Butyrolactone, b.p. 209°, is obtained from jS-acetobutyric acid.
aa-Dimethyl Butyrolactone, b.p. 202°, is formed, together with its isomer
ftp-Dimethyl Butyrolactone, by reduction of unsym.-dimethyl succinic ester as
anhydride (C. 1904, I. 925 ; II. 587).
Isocaprolaetone, y-Dimethyl Butyrolactone, (CH3)2CCH2CH2COO, m.p. 7°,
b.p. 207°, is produced together with pyroterebic acid in the distillation of terebic
acid. (See general method 4, p. 372.) Pyroterebic acid itself passes on long
boiling into isocaprolactone. It can also be obtained from isobutyric aldehyde,
malonic acid and acetic anhydride (B. 29, R. 667).
LACTONES 375
Lactones; C7H13O2. y-n-Propyl Butyrolactone, y-n-Heptolactone,, CH8CH2-
CH2CHCH2CH2COO, b.p. 235°, is obtained from y-bromcenanthic acid, from
n-propyl paraconic acid, and from dextrose carboxylic acid, as well as from
galactose carboxylic acid on treatment with hydriodic acid (B. 21, 918). y-Iso-
propyl Butyrolactone, (CH8)8CH.CHCH2CH2COO, b.p. 224°, is formed from
isopropyl paraconic acid, a- and fi-Isopropyl Butyrolactone are obtained from
isopropyl succinic anhydride. aay-Trimethyl Butyrolactone, a-Dimethyl Valero-
ylactone, CHS.CH.CH2C(CH,),COO, m.p. 52°, b.p.ia 86°, may be obtained
from a-dimethyl laevulinic acid (mesitonic acid (q.v.) and from aay-trimethyl
vinyl acetic acid (C. 1904, I. 720). ayy-Trimethyl Butyrolactone, m.p. 50°, is
prepared from ayy-trimethyl j8-hydroxybutyric acid (comp. p. 369) (C. 1897, II.
572). a-Ethyl y-M ethyl Butyrolactone, b.p. 219°, is prepared from a- ethyl jS-
acetopropionic acid and ethyl allyl acetic acid, mode of formation, No. 3 (B. 29,
l857)- yy-Ethyl Methyl Butyrolactone, b.p.1§ 106°, is obtained from laevulinic
ester and ethyl magnesium halides.
Lactones: C,H14O,.
y-Isobutyl Butyrolactone is prepared from isobutyl paraconic acid, a-Propyl
y-Methyl Butyrolactone, b.p. 233°. a-Isopropyl y-Methyl Butyrolactone, b.p. 224°
(B. 29, 1857, 2001). a-Ethyl py-Dimethyl Butyrolactone, b.p. 227°, is obtained
from a-ethyl j8-methyl /?-acetopropionic acid. y-Diethyl Butyrolactone, b.p. 228-
233°, is prepared from succinyl chloride and zinc ethyl.
S-Lactones are obtained from the corresponding S-halogen carboxylic acids by
distillation, or from the 8-keto-carboxylic acids (p. 424), as well as from glutaric
esters or anhydride (p. 501) by reduction. B-Valerolactone, CH8CH2CH2CH2COO,
b.p.14 114°, changes spontaneously into a polymer, m.p. 48°, which is decom-
posed by alkali into 8 -hydroxy valeric acid, as is also the simple lactone (B. 26,
2574; 36, 1200; A. 319,367). B-Methyl8-Valerolactone,S-Caprolactone,Ctll19Ot,
m.p. 13°, b.p. 275°. a- or y-Methyl 8-Valerolactone (B. 36, 1201). aa-Dimethyl
8-Valerolactone, C7H12O2, b.p.15 105°. ^-Dimethyl 8-Valerolactone, m.p. 30°,
b.p. 225° (C. 1905, II. 753). y-Ethyl ^-Methyl 8-Valerolactone, b.p. 255° (A. 216,
127; 268, 117).
e-Hydroxy-carboxylic Acids and hydroxy-acids containing a still more remote
position of the alcoholic CH-group show no further tendency to lactone-formation.
They seem rather to split off water like the j8-hydroxy-acids, since olefine car-
boxylic acids are obtained from the corresponding amino-carboxylic acids with
nitrous acid, together with or instead of the hydroxy-acids (A. 343, 44).
However, e-Laetones have been obtained by the oxidation of certain terpene
ketones with permonosulphuric acid (Caro's acid). fi-Methyl c-Isopropyl c-
Caprolactone, C8H7kHCH8CH2CH(CH8)CH?COO, b.p.1? 129°, m.p. 4-8° and 47°.
according to the geometrical isomer. It is obtained from menthone (Vol. II.).
The two isomers yield hydroxy-acids, one fluid and the other, m.p. 65° ; but only
one e-keto-acid is obtained by oxidation. Tetrahydrocarvone (Vol. II.) similarly
treated yields fi-Isopropyl e-Methyl e-Caprolactone, b.p.21 156°. Methyl Cyclo-
hexanone (Vol. II.) gives rise to a lactone, which, on breaking down, passes into
methyl e-hydroxycaproic acid. Suberone (Vol. II.) appears to give a ^-lactone which
passes into ^-Hydroxy osnanthylic acid, HOCH2[CH2]BCOOH, on decomposition
(B. 33, 858).
c-Hydroxycaproic Acid, HO[CH2]6.COOH ; phenyl ether, C«H,O[CH2],COOH,
m.p. 71°, is obtained by adding potassium cyanide to e-chloramyl phenyl ether
and hydrolyzing the resulting nitrile (B. 38, 965).
lo-Hydroxyundecylic Acid, HOCH2[CH2]tGOOH, m.p. 70°, is obtained from
cu-bromundecylic acid and silver oxide. Oxidation converts it into nonane
dicarboxylic acid (C. 1901, II. 1043). g-Hydroxystearic Acid, CtH17CH(OH)-
[CHjJgCOOH, m.p. 83°, is produced from oleic acid through iodo- or sulpho-
stearic acid (p. 377). If oleic acid is heated with zinc chloride it is converted
into the so-called stearolactone, C18H82Oa, probably y-tetradecyl butyrolactont
(C. 1903, I. 1404). i^-Hydroxybehenic Acid, CtH1T.CH(OH)C12H,4COOH, m.p.
90° (C. 1908, I. 2019).
376 ORGANIC CHEMISTRY
Sulphur Derivatives of the Hydroxy-acids :
Only the mercaptan carboxylic acids and their reaction products
will be considered here. These are acids which at the same time
possess the nature of a mercaptan. They are obtained as oils, with a
disagreeable odour, and are miscible with water, alcohol, and ether.
1. Mercaptan Carboxylic Acids are prepared (i) from halogen-fatty acids
and KSH ; (2) the xanthogen-fatty acids resulting from potassium xantho-
genate (q.v.) and chloro-fatty acids, are decomposed by ammonia into mercaptan-
carboxylic acid and xanthogen amide (B. 39, 732 ; A. 348, 120) :
ClCH2COOK-fKSH=HSCH,COOK+KCl
CaH6OCS.SCH(CH8)COONH4+NH,=HSCH(CH8)COONH4+C2H6OCS.NHa.
(3) The mercaptan- or thio-carboxylic acids are easily oxidized to disulphides,
such as (HOOCCH2)2S2, which may also be prepared directly from halogen-fatty
acids and potassium polysulphides ; on reduction, the mercaptan carboxylic
acids are re-formed (6.1907, I. 856 ; 1908, I. 1221).
These bodies tend to form complex salts.
Thioglyeollic Acid, [Ethanethiol Acid], HS.CH2COOH, m.p. -—16-5°, b.p.18
103°, is obtained from monochloracetic acid and potassium hydrogen sulphide ;
and from thiohydantoin, when heated with alkalis (A. 207, 124). On adding
ferric chloride to its solution an indigo-blue coloration is obtained. It is a dibasic
acid. (Conductivity, B. 39, 736.) The barium salt, S.CH2COOBa+3H2O, dissolves
with difficulty in water ; ethyl ester, b.p.17 55° ; amide, m.p. 52°. On being
heated, it yields the thioglycollic acid thiogly collide (SCH2CO)X, m.p. about 80°.
a-Thiolactic Acid, CH3CH(SH)CO2H, m.p. 10°, b.p.14 99°, is prepared from
pyroracemic acid (p. 407) and sulphuretted hydrogen ; also, together with
cysteine, a-amino-/?-thiopropionic acid (q.v.) (C. 1903, I. 15), from horn (keratin)
by decomposition with hydrochloric acid. fi-Thiolactic Acid, HS.CH8CH2CO2H,
m.p. 16 8°, b.p.16 11°, D20 = i-2i8.
a-Thiobutyric acid, b.p.19 118-122° ; a-Thioisobutyric acid, m.p. about 47°,
b.p.16 102°.
The first product of reaction of KSH and y-chlorobutyronitrile is probably
Dithiobutyrolactone, which loses H2S and condenses further to the red coloured
Trithiodibutyrolactone, C8H10S3, m.p. 116°. Its structure is probably analogous
to that of the condensation ^production of the lactone with sodium ethoxide
(p. 374) (B. 34, 3387).
2. a-Alkyl Sulphide Carboxylic Acids are obtained from the interaction of
a-halogen fatty acids and sodium mercaptides. Ethyl Sulphide Acetic Acid,
C2H6S.CH2COOH, m.p. -87°, b.p.n 118° ; D20 1-1518 (B. 40, 2588).
3. a-Mercaptal Carboxylic Acids result from the action of a-thio-acids on
aldehydes. Ethylidene Dithiogly collie Acid, CH8CH:(SCH2.COOH)2, m.p. 107°.
4. a-Mercaptol Carboxylic Acids result from a-thio-acids and ketones in the
presence of zinc chloride or HC1.
Dimethyl M ethylene Dithioglycollic Acid, (CH8)2C:(SCH2COOH)2, m.p. 126°.
5- a-Sulphide Dicarboxylie Acids are produced when K2S acts on a-halogen
fatty acids.
Thipdiglyeollic Acid, S(CH2CO2H)a, m.p. 129°, corresponds in composition
with digly collie acid (p. 367), and under like conditions forms a cyclic anhydride,
which is both a sulphide and a carboxylic anhydride. Thiodiglycollic Anhydride,
S<^CH2CO->°' m'P' I02°» b-P-io I58° (B- 27, 3059). a-Thiodilactylic Acid,
S[CH(CH8)C02H]2, m.p. 125°. y-Thiodibutyric Acid, m.p. 99° (B. 25, 3040).
nsym.-Sulphtde Dicarboxylie Acids are obtained from the disodium salts of the
mercaptan carboxylic acids and sodium halogen fatty acids in aqueous solution
(B. 29, 1139).
6. Bisulphide Dicarboxylie Acids are readily produced in the oxidation of
the mercaptan carboxylic acids in the air, or with ferric chloride or iodine.
Dithiodiglycollic Acid, S2(CH2CO,H)2, m.p. 100°. a-Dithiodilactic Acid, S2[CH-
m.p. 141°. p-Dithiodipropionic Acid, S,(CH8CH2COOH)a, m.p.
SULPHUR DERIVATIVES OF THE HYDROXY-ACIDS 377
155° (A. 339, 351). Trisulphide Acetic Acid, S3(CH2COOH)2, m.p. 124°. Tetra-
sulphide Acetic Acid, S4(CHaCOOH)2, m.p. 113° (A. 859, 81).
COOH
7. Hydroxysulphine Carboxylic Acids. — The free bodies — e.g. \
CH2S(CH3)aOH,
are unstable. They split off water and yield cyclic sulphinates, which are con-
stituted similarly to the cyclic ammonium compounds, and are called thetines.
This name, from the contraction of thio and betaine, is intended to express the
analogy between their derivatives and betaine (B. 7, 695 ; 25, 2450 ; 26, R.
4°9) :
™ co°
CH,-S<£H». Dimethyl Thetin, ; iH j,(CH,,,, betaine (p. 330).
The thetines are feeble bases. Their hydrobromides are produced when
methyl sulphide, ethyl sulphide, and sodium thiodiglycollate are brought into
action with o-halogen fatty acids — e.g. chloracetic acid and o-bromopropionic acid.
Dimethyl Thetine, (CH3)2SCH2COO, is deliquescent.
Methyl Ethyl Thetine, QC^3>S<CQa>CO, contains an asymmetric sulphur
atom, and is resolved into its two forms by means of its salts with camphor-sul-
phonic acid and bromocamphor-sulphonic acid: d-chloroplatinate, [a]D=+4'5*
(C. 1900, II. 623).
Dimethyl Thetine Dicarboxylic Acid, (HO.OC.CH2)2S.CH2.COO, m.p. 157-
158°. Diethylene Disulphide Thetine (C. 1899, II. 1105). Further compounds,
B. 33, 823.
Selenetines, see B. 27, R. 801.
8. Sulphone Carboxylic Acids are produced by the action of alkyl sulphinates
on esters of halogen fatty acids, and resemble the ketone Carboxylic acids (q.v.).
Ethyl Sulphone Acetic Acid, C2H6SO2.CH2CO2H. Ethyl Sulphone Propionic
Acid, C2H6SO2.CH2CH2CO2H (B. 21, 89, 992). By oxidizing the sulphide, corre-
sponding with the sulphones with KMnO4, there are obtained : Sulphone Diacetic
Acid, O8S(CH2CO2H)a, m.p. 182°. a- Sulphone Dipropionic Acid, O2S[CH(CH3).-
CO2H]a, m.p. 155° (B. 18, 3241). Sulphone diacetic acid resembles acetoacetic
ester in many respects. For mixed sulphone-di-fatty acids see B. 29, 1141.
9. a-Sulphocarboxylic Acids. The sulpho-acids of the fatty acids are pro-
duced by methods similar to those employed with the alkyl sulphonic acids :
(1 ) By the action of sulphur trioxide on the fatty acids, or by acting with
fuming sulphuric acid on the anhydrides, nitriles, or amides of the acids (J. pr.
Ch. [2] 73, 538 ; C. 1905, I. 1309).
(2) By heating concentrated aqueous solutions of the salts of the mono-
substituted fatty acids with alkali sulphites.
(3) By the addition of alkali sulphites to unsaturated acids (B. 18, 483).
(4) By oxidizing the thio-acids corresponding to the hydroxy-acids with nitric
acid.
(5) Upon oxidizing glycol sulphonic acids, e.g. isethionic acid, with nitric acid.
These sulpho-acids are dibasic acids, corresponding with malonic acid in their
chemical behaviour. They are, however, more stable towards heat, alkalis, and
acids.
Sulpho-acetic Acid, HO3S.CH2COOH, is prepared by decomposing acetone
trisulphonic acid by means of alkali ; methionic acid is formed at the same time
(p. 210) (C. 1902, I. 101). Chlorosulphonic Acetyl Chloride, ClO2S.CHaCOCl,
b.p.i50 130-135°, is converted into thioglycollic acid by reduction. Ethyl
Sulphonic Ethyl Acetic Ester, C2H6O3S.CH2COOC2H6, is obtained as an oil,
volatile with partial decomposition. The hydrogen atoms in the CH2-group
can be replaced by alkyl groups, comparable to the esters and amides of methionic
acid (p. 210), to form acetoacetic ester (p. 410) and to malonic ester (B. 21,
1550).
Sulpho-isobutyric Acid, HO3S.C(CH8)2COOH, is formed by the interaction
of isobutyryl chloride or anhydride and concentrated sulphuric acid. The
barium salt ( + 3H2O) is less easily soluble in hot water than in cold ; dimethyl ester,
m.p. 4°, b.p. 78-82° ; dichloride, m.p. 10°, b.p. 55° (C. 1905, I. 1309),
378 ORGANIC CHEMISTRY
NITROGEN DERIVATIVES OF THE HYDROXY- ACIDS
The following classes of nitrogen compounds are derived from
the a-hydroxy-acids : (i) Amides. (2) Imidohydrins. (3) Hyclra-
zides. (4) Azides. (5) Nitriles. (6) Nitro-acids. (7) Nitroso-acids.
(8) Hydroxylamino-acids. (9) Amidoxy-acids. (10) Amino-acids.
(n) Nitramino-acids. (12) Isonitramino-acids. (i3#) Hydrazine
acids. (136) Hydrazo-acids. (14) Azo-acids.
The a-amino-acids and their derivatives are of especial interest
from the physiological standpoint, as being decomposition products of
the proteins.
1. Hydroxyamides. — The o-hydroxyamides are produced (i) by treating
(a) alkyl esters and (6) cyclic double esters of the lactides with ammonia.
(2) From the a-hydroxynitriles by the absorption of water in the presence of
a mineral acid, particularly sulphuric acid. They behave like the fatty acid
amides.
Glyeollamide, HOCH2CO.NHS, m.p. 120°, is obtained from polyglycollide,
or from acid ammonium tartronate when heated to 150°. It possesses "a sweet
taste.
Laetamlde, CH,CH(OH).CONH2, m.p. 74°.
a-Hydroxycaprylamide, CH3(CH2)SCH(OH)CONH2, m.p. 150° (A. 177, 108).
Diglycollic acid yields two amides and a cyclic imide :
Diglycollamic Acid, NH2COCH2OCH2CO2H, m.p. 135°.
Diglycollamide, O(CH2CONH2),, breaks down when heated into ammonia and
diglycollimide, O<£^a'£o>NH, m.p. 142°. It behaves like the imides of the
dicarboxylic acids, e.g. succinimide (q.v.) and tt-glutarimide.
The readily decomposable additive products, arising from ammonia and the
y-lactones (A. 256, 147), are regarded as being as y-hydroxy-acid amides. Yet
they are said to have a constitution similar to aldehyde-ammonia (A. 259, 143).
The additive product from ammonia and y-valerolactone may have one of the
following formulae :
CH3CHCH2CH2CONHa or CH3.CH.CH2.CH2C<gg*.
OH O 1
The addition products of hydrazine and y-lactones behave similarly : Hydva-
ziney-Valerolactone,6.CH(CH3)CHzCH,lC(OH), m.p. 62°, also easily dissociates
into hydrazine and lactone (C. 1905, I. 1221).
2. a-Hydroxy-imldohydrins. The imido-ethers of the a-hydroxy-acids, whose
salts are prepared in the ordinary way from nitriles by means of alcohols
and HC1 (p. 281), are hydrolyzed when in the free state by water, into the imido-
hydrins. These are isomeric with the corresponding amides, although they
appear to consist of a double molecule and behave as electrolytes in aqueous
solution (B. 30, 998 ; 34, 3142).
Glycoliminohydrin, (HOCH2C<Q**)a, m.p. 160°; Lactimidohydrin, m.p.
135° ; Hydroxyisobutyl Imidohydrin, m.p. 173°.
3. Hydrazides of the Hydroxy-aeids: Glycol Hydrazide, HOCH2CO.NHNH2,
m.p. 93°, has been prepared from benzoyl or oxalyl glycollic ester and hydra-
zine hydrate (J. pr. Ch. [2], 51, 365).
4- Azides of the Hydroxy-aeids: Glycol Azide, HOCH2.CON3, is formed when
sodium nitrite acts on the hydrochloride of glycol hydrazide. It crystallizes
from ether (J. pr. Ch. [2], 52, 225).
5. Nitriles of the Hydroxy-aeids.
The nitriles of the a-hydroxy-acids are the additive products
obtained from hydrocyanic acid and the aldehydes, and ketones.
NITROGEN DERIVATIVES OF THE HYDROXY-ACIDS 379
The aldehydes yield nitrites of secondary hydroxy-acids. Formalde-
hyde is an exception in this respect, for it gives rise to the nitrile of a
primary hydroxy-acid, — gly collie acid.
The ketones yield nitriles of tertiary hydroxy-acids.
CH3CH:0+HNC=CH8CH<Q^ Nitrile of lactic acid (p. 362).
(CH3)8C:O+HNC=(CH8)aC<Q^ Nitrile of acetonic acid (p. 365).
These nitriles of the a-hydroxy-acids have been called the cyan-
hydrins of the aldehydes and ketones. They result by the reaction
of the aldehyde and ketone bisulphite compounds (pp. 207, 225} with
potassium cyanide (B. 38, 214 ; 39, 1224, 1856).
Many of the anhydrous substances boil without decomposition,
especially under reduced pressure ; but many break down upon the
evaporation of their aqueous solution, and alkalis resolve them into
their components. The nitriles of the a-hydroxy-acids, on the other
hand, under the influence of mineral acids, e.g. hydrochloric acid and
sulphuric acid, first take up one molecule of water and change to
a-hydroxy-acid amides (see above), then a second molecule of water,
and form the ammonium salts of the a-hydroxy-acids, which are imme-
diately decomposed by mineral acids (p. 277).
When heated with P2O5 they change into olefine carboxylic nitriles ; with
PCI 6 into chloroparaffin carboxylic nitriles (C. 1898, II. 22, 662). Ammonia
causes the formation of water and amino-nitriles (p. 381). Cyanacetic ester
and the a-hydroxy-acid nitriles produce water and derivatives of ajS-dicyano-
propionic acids, R,C(CN).CH(CN)COaC2H5 (C. 1906, II. 1561).
Aldehyde Cyanhydrins.
Gly collie Acid Nitrile [Ethanol Nitrile], HO.CH2CN, b.p. 183° with decomposi-
tion, b.p.2e 103° (J- pr. Ch. [2] 65, 189). Acyl Glycollic Nitriles are prepared
from chloracetic nitrile with the sodium or potassium salts of the fatty acids
(C. 1904, II. 1377). Fprmyl Gycollic Acid Nitrile, HCO2CH2CN, b.p. 173°, and
Acetyl Glycollic Acid Nitrile, b.p. 180°, result also fromglycol aldoxime and acetic
anhydride, and are decomposed by ammoniacal silver oxide into AgCN and
formaldehyde (C. 1900, II. 313). Ethers of glycollic nitrile are prepared from
chloromcthyl alkyl ethers and silver, mercury, or copper cyanide :
2CH3OCH2Cl-fHg(CN)2=2CH3OCH2CN+HgCl2.
Methoxyacetonitrile, b.p. 120° ; Ethoxyacetonitrile, b.p. 135° (C. 1907, I.
400, 871).
Ethylidene Lactic Acid Nitrile, Aldehyde Cyanhydrin, CH3CH(OH)CN,
b.p. 30 102° ; ethyl ether, CH3CH(OC2H6)CN, b.p. 88°, is prepared from cyanogen
chloride and ethyl ether (B. 28, R. 15) ; acetyl ester, CH3CH(OCOCH3)CN, b.p.
169° (B. 28, R. 109) ; a-Hydroxyisovaleric Acid Nitrile, (CH3)2CH.CH(OH)CN,
decomposes at 135°, a-Hydroxycaprylic Acid Nitrile, (Enanthol Hydrocyanide,
CHS[CH2]5CH(OH)CN.
Halogen Substitution Products of the Aldehyde Cyanhydrins (A. 179, 73) :
Chloral Cyanhydrin, CC13CH(OH)CN, m.p. 61°, boils with decomposition at
215-230°. Tribromolactic Acid Nitrile, CBr3CH(OH)CN. Both compounds
can also be looked on as trihalides of orthotartronic acid nitriles. Trichloro-
valerolactic Acid Nitrile, CH3CC12CHC1.CH(OH)CN, m.p. 103°.
Ketone Cyanhydrins : a-Hydroxyisdbutyric Acid Nitrile, Acetone Cyanhydrin,
(CH3)2C(OH)CN, m.p.— 19°, b.p.as 82°. Methyl Ethyl Glycollic Acid Nitrile.
(C2H6)(CH3).C(OH)CN, b.p.20 91°. Diethyl Glycollic Acid Nitrile, (C2H5)2.-
C(OH)CN, b.p.88 110°. fi-Chloro-a-hydroxyisobutyric Acid Nitrile, C1CH,C(CHS)-
(OH)CN, m.p.22 110°. Methyl tert. -Butyl Glycollic Acid Nitrile, (CH8)3CC(CH3).-
(OH)CN, m.p. 94°, is prepared from pinacoline (A. 204, 18 ; B. 14, 1974 ; 39, 1858;
C. 1906, II. 596).
38o ORGANIC CHEMISTRY
Nitrites of the hydroxy-acids have been prepared from the halogen glycol-
hydrins (p. 319) by the action of potassium cyanide. Ethylene Cyanhydrin,
B-Lactic Acid Nitrite, HOCH2CH2CN, b.p. 220°, is also obtained from ethylene
oxide and hydrocyanic acid. p-Ethoxybutyronitrile, CH3CH(OC2H6)CH2CN,
bp 173°, is prepared from allyl cyanide and ethyl alcohol (B. 29, 1425). y-
Methoxybutyronitrile, CHsO[CHa]3.CN, b.p. 173° (B. 32, 948).
t-Phenoxycapronitrile, C6H6O[CH2]5.CN, m.p. 36°, from e-chlorocapronitrile
and sodium phenolate (B. 38, 178).
The groups of substances, which are dealt with in the following sections,
are closely connected with one another and with the hydroxy-carboxylic acids.
When the alcoholic hydroxyl group of the latter is replaced by the groups
— NOa, —NO, — NHOH, and — NH2, a whole series of nitro-, nitroso-, hydroxyl-
amine- and amino-carboxylic acids are produced.
6. Nitro-fatty Acids. a-Nitro- fatty Acids are only known in the form of
derivatives. When potassium nitrite acts on potassium chloracetate there
is first formed potassium nitro-acetic acid which decomposes into nitromethane
and potassium bicarbonate (comp. p. 149) :
KN02 H2O
CH2C1COOK > N02CH2C02K > CH3NO2+KHCO8.
When silver nitrite and bromacetic ester react, the expected nitro-acetic ester
is replaced by two peculiar bodies containing less water, which are derivatives
of oxaftcacid: oxalic ester nitrile oxide, C2H6OCO.CjN:O, m.p. m°, and bis-
anhydro-nitro- acetic ester, (C2H5OCOCNO)2, b.p.n 160°, which on reduction
yields glycol, like a true nitro-acetic ester. Similarly, iodo-acetonitrile and
silver nitrite do not yield nitro-acetonitrile, but a dimolecular body, deficient in
water, cyanomethazonic acid, which perhaps should be considered as being
isonitroso-nitro-succinic acid nitrile, NG.C(NOH).C(NOOH)CN (cornp. methazonic
acid, p. 339) (B. 34, 870).
The real nitro-acetic ester, NO2.CH2.COOC2H5, b.p.1Q 94°, is prepared from
nitromalonic ester, NO2CH(COOC2H,)2 and KOH ; also from o-nitrodimethyl
acrylic ester, (CH3)2C:C(NO2)COOC2H6, by the decomposing action of ammonia ;
also, particularly easily, from acetoacetic ester by the action of concentrated
nitric acid and acetic anhydride, together with bis-anhydro-nitro-acetic ester
(see above) (C. 1904, II. 640). Reduction changes it to hydroxylamino-acetic
acid and glycocoll (C. 1901, II. 1259; comp. I. 881). Like other nitro-bodies,
nitro-acetic acid forms salts (p. 149), MeOON:CHCO2C2H6. When the ammonium
salt is precipitated with mercuric chloride a very stable mercury nitro-acetic ester,
O<Qj|^>C.COaC2H6, is formed, which is soluble in alkalis and hydrochloric
acid, and with bromine forms nitrodibromacetic ester, NO2CBr2CO2C2H6, b.p.n
131-134° (B. 39, 1956). Heating with ammonia at 100° converts it into nitro-
acetamide, NO2CH2CONH2, m.p. 101-102°, with decomposition. This can also
be formed by alkaline decomposition of nitro-malonamide. Its silver salt
reacting with iodo-alkyls give 0-ethers, such as CH3OON:CHCONHa and
C2H6OON:,CHCONH2, which decompose readily into aldehyde and isonitroso-
acetamide, HON:CHCONH2. Nitrodibromacetamide, NO2CBr2CONH2, and
nitrobromacetamide, NO2CHBrCONHa, m.p. 79° (C. 1906, 1. 910; B. 37, 4623).
Nitro-acetonitrile, NO2CH2CN, b.p.14 96°, is prepared from methazonic acid
(nitro-acetaldoxime, p. 339) and thionyl chloride. With bromine it gives nitro-
dibromacetonitrile, NO2CBr2CN, b.p,12 58°, which is a different body from
dibromoglyoxime peroxide (p. 250) (B. 41, 1044).
Homologues of the a-nitro-fatty esters, such as a-nitropropionic ester, CH3CH-
(NOa)C02C2H6, b.p. 190-195°: a-nitrobutyric ester, C2HBCH(NO2)CO2C2H5,
b.p.20 123°, are obtained from the alkyl-nitro-malonic esters and sodium alcoholate
(C. 1904, II. 1600). a-Nitro-isobutyric Acid, (CH8)2C:(NO2)COOH : nitrile,
m-P- 53°, is obtained by oxidation of nitroso-isobutyric nitrile (p. 381) with nitric
acid ; amide, m.p. 118°.
^-Nitro-fatty Acids'. fi-Nitropropionic Acid, NO2CH2CH2CO2H, m.p. 66°,
is prepared from /3-iodopropionic and silver nitrite; ethyl ester, b.p. 161-165°.
B-Nttro-isovaleric Acid, (CHs)2C(NO2).CHaCOaH, is obtained together with
dwitropropane, (CH3)aC(NOa)a, by the action of nitric acid on isovaleric acid
(B. 15, 2324).
NITROGEN DERIVATIVES OF THE HYDROXY-ACIDS 381
7. Nitroso-fatty Acids. From the examination of the nitroso-paraffins (p. 152)
it is clear that the mtro-fatty acids, which contain the group — CH2.NO or
=CH.NO, must undergo transformation into the isonitroso- or oximido-fatty
acids, which will be considered later as derivatives of the aldehyde- and ketone-
acids respectively (pp 410, 416, 424). On the other hand, oxidation by chlorine of
hydroxyl-amino-isobutyric acid nitrile (see below) yields the Nitrile of Nitroso-
isobutyric Acid, (CH3)2C(NO)COOH, m.p. 53°, to a blue liquid ; amide, m.p.
158° with decomposition ; ester, m.p. 89° ; amidine, (CH8)2C(NO)C(NH)NHj,
is converted by hydrocyanic acid, etc., into a series of peculiar bases (B. 34,
1863 ; 36, 1283).
8. Hydroxylamino-fatty Acids. Their nitriles result from the combination
of hydrocyanic acid with aldoximes and ketoximes (p. 382) (B. 29, 65). Hydroxyl-
amino-acetic Acid, HONH.CHaCOOH, m.p. 132°, is obtained from isonitramino-
acetic acid (p. 397) and from nitro-acetic ester (see above), also from isobenzal-
doxime acetic acid (Vol. II.) (B. 29, 667). a-Hydvoxylaminobutyric Acid,
CHS.CH2CH(NHOH)COOH, decomposes at 166° ; nitrile, m.p. 86°, results from
propionaldoxime and HNC (B. 26, 1548). a-Hydroxylamino-isobutyric Acid,
(CH3)2C(NHOH)COOH, is prepared from isonitramino-isobutyric acid (p. 397);
nitrile, m.p. 98°, is produced from acetoxime and HNC ; further derivatives, see
B. 34, 1863.
9. Amidoxyl-fatty Acids are isomeric with the hydroxylamino-fatty acids.
Amidoxyl-acetic Acid, NH2OCH2COOH, is obtained by the breaking down of
ethyl benzhydroxime acetic acid, C6H6C(OCaH6):NOCH2COOH. Homologues,
see B. 29, 2654.
10. Amido- or Ammo-fatty Acids.
In the amino-acids the alcoholic hydroxyl of the dihydric acids is
replaced by the amido-group NH2 :
CH2.OH CH2.NH,
CO.OH CO.OH
Glycollic Acid. Glycolamino-acid.
It is simpler to consider them as being amino-derivatives of the
monobasic fatty acids, produced by the replacement of one hydrogen
atom in the latter by the amido-group :
CH8 CHj.NH,
CO.OH CO.OH
Acetic Acid. Aminoacetic Acid.
Hence they are usually called amino- or amido-fatty acids.*
The firm union of the ammo-group in them is a cha-
racteristic difference between these compounds and their isomeric
acid amides. Boiling alkalis do not eliminate it (similar to the
amines). Several of these amino-acids occur already formed in plant
and animal organisms, to which great physiological importance is
attached. They can be obtained from proteins by heating the latter
with hydrochloric acid, or alkalis, or by the action of ferments or
bacteria. They have received the name alanines or glycocolls from
their most important representatives.
. The general methods in use for preparing the amino-acids are :
(i) The transposition of the monohalogen fatty acids when heated
with ammonia (similar to the formation of the amines from the alky-
logens, p. 157) :
* Modern and stricter nomenclature reserves the term amido- for the — CONH,
group. — (TR.)
382 ORGANIC CHEMISTRY
Thus chloracetic acid yields :
(CHXOOH (CH2COOH (CH2COOH
N H NCHCOOH N CH.COOH
|H |CH,COOH
Aminoacetic Acid. Imiaodiacetic Acid. Nitrilotriacetic Acid.
(2) In the action of the halogen fatty acids on ammonia, phthal-
imide may be employed to promote the reaction, where the halogen
fatty-acid esters are allowed to react with potassium phthalimide,
after which the amino-acid is split off by hydrochloric acid at 200° C. :
ClCHaCOOCaH5 m CO,CtH6 HCl C02C2H6
Potassium Phthalimide. Phthalyl Glycocoll Ester.
(3) The reduction of nitro- and isonitroso-acids (p. 380) with
nascent hydrogen from zinc and hydrochloric acid or aluminium
amalgam in ether (C. 1904, II. 1709) :
6H
CH2N02COOC2H6 - > CH2NH2C09H
Nitroacetic Ester. Aminoacetic Acid.
4H
(CH3)2CHCH2C(NOH)CO2C2H5 - -> (CH3)2CHCH2CH(NH2)COOH
Isobutyl Isonitroso-acetic Ester. »-Leucine(a-Aminoisocaproic Acid).
(4) Reaction of the cyano-fatty acids (q.v.) with nascent H (Zn
and HCl, or by heating with HI), in the same manner that the amines
are produced from the alkyl cyanides (p. 158) :
CN.COOH+2Ha=CH2(NH2)C02H
Cyanoformic Acid. Aminoacetic Acid.
This reaction connects the ammo -fatty acids with the fatty acids
containing an atom less of carbon, and also with the dicarboxylic acids
of like carbon content, whose half nitriles are the cyano-fatty acids.
(5«) The nitriles of the a-amino-acids are prepared by allowing a
calculated quantity of ammonia, in alcoholic solution, to act on
the hydrocyanic acid addition-products of the aldehydes and ketones,
and then setting free the hydrochlorides of the a-amino-acids from
these by means of hydrochloric acid (B. 13, 381 ; 14, 1965) :
HNC NH. HCl
CH8CHO - > CH8CH<gN - > CH,CH<CN ^ - > CH8CH<CO2H
HNC NH, 2 HCl
(CH,)aCO - > (CH8),C<CN - ^ (CH8)2C<CN ^__>. (CH8)aC<CO2H
(56) Nitriles of a-amino-acids can also be synthetically obtained
from the aldehyde-ammonias by means of hydrocyanic acid ; also
from aldehydes by means of ammonium cyanide (B. 14, 2686) :
NH4NC
CH8CHO.
Ketones also unite with ammonium cyanide to form nitriles of the a-amino-
dialkyl acetic acids (B. 33, 1900 ; 39, 1181).
Aldehydes and ketones may, with advantage, be allowed to act on a mixture
of potassium cyanide and ammonium chloride (B. 39, 1722). When potassium
cyanide reacts with aldehydes in bisulphite solution (p. 380) and is followed by
NITROGEN DERIVATIVES OF THE HYDROXY-ACIDS 383
primary and secondary amines, then alkyl and dialkyl aminonitriles are formed
(B. 38, 213).
Hydrocyanic acid attaches itself similarly to the oximes (B. 25, 2070), to the
hydrazones, and to the Schiff bases, with the production of nitriles of a-hydroxyl-
amino acids, phenylhydrazino-acids and alkylamino-acids (B. 25, 2020 ; C. 1904,
II. 945).
The methods (50) and (56) are only suitable for the production of
a-amino-fatty acids, whilst the other methods serve also for the pre-
paration of J3-, y-, and 8-amino-fatty acids, which are also produced :
(6) By the addition of ammonia to olefine monocarboxylic acids.
(70) By the oxidation of amino-ketones, e.g. diacetonamine (p. 230),
and (76) by the breaking down of the cyclic imines of glycols upon
oxidation (see piperidine).
Properties. — The amino-acids are crystalline bodies usually pos-
sessing a sweet taste. They are readily soluble in water, but usually
are insoluble in alcohol and ether.
Constitution. — As the amino-acids contain both a carboxyl and an
amino-group, they behave as both acids and bases. Since, however,
the carboxyl and amino-groups mutually neutralize each other, the
amino-acids show a neutral reaction, and it is very probable that both
groups combine to produce a cyclic ammonium salt :
This is supported by the existence and mode of formation of trimethyl
glycocoll or beta'ine, as well as of the homologous j8- and y-betaines
(comp. pp. 386, 393) :
N(CH,),\ CHa— N(CH3)8\ CH,— N(CH,)8v
i >o i /° i ;>o.
CH2.C(X CHa - CCT CH,.CH,— CCT
The formation of salts provides a method of separation of the two
groups (B. 35, 589).
The esters of the a-amino-carboxylic acids are of special importance, partly
as providing the materials from which the diazo-ester (below) is produced, and
partly because it is by their preparation that the mixture of o-amino-acids
which results from the hydrolysis of proteins, can be separated and purified
(B. 39, 541)-
These esters are best obtained as hydrochlorides by warming the acids with
alcohols and hydrochloric acid. The free amino-esters are liquids which can be
distilled under reduced pressure, possess the characteristics of amines, and
are fairly easily hydrolyzed. Heat converts them into cyclic double amides
(di-aci-piperazine) (p. 391).
Reactions. — The amino-acids form (i) metallic salts with metallic oxides and
(2) ammonium salts with acids.
In the presence of alkalis and alkali earths, carbon dioxide forms salts of
carbamino-carboxylic acid, of which the Ba or Ca salt, OCO.NH.CH,COOBa,
is most suited for its separation on account of its low solubility (B. 89, 397 ; Ch.
Z- 1907, 937)-
(3) The replacement of the carboxylic hydrogen by alcohol radicals
produces esters, which are highly reactive.
(4) Phosphorous chloride converts the amino-acids, suspended in
acetyl chloride, into hydrocWorides of the highly reactive amino-acid
chlorides (E. Fischer, B. 38, 2914) :
384 ORGANIC CHEMISTRY
(5) The hydrogen of the ammo-group can also be replaced by acid
and alcohol radicals. The acid-derivatives are obtained by the action
of acid chlorides on an alkaline solution of the acid, or in presence of
bicarbonate, or on the ester in a neutral solvent :
CH«<CO H +CaH8OCl=CH2<co2H2H30+HC1-
Acetyl Amino-acetic Acid.
Acyl groups can be substituted into the amino-acids by means of acid
anhydrides and acid azides (J. pr. Ch. [2] 70, 57) '. the formyl group merely by
warming with absolute formic acid (B. 38, 3997)- Those acyl derivatives which
serve most suitably for identifying the amino-acids are the benzoyl-, benzene
sulphonic- 1 and naphthalene sulphonic- compounds, such as C6H6.CO.NHCH2-
COOH, CaH6SOa.NHCHaCOOH, C10H7SO2.NHCH8COOH. Another class of
derivatives is the phenyl ureSdo-acids, such as C6H6.NHCONHCH2COOH, pro-
duced by phenyl cyanate (Vol. II.) in alkaline solution (B. 35, 3779 ; 39, 2359).
The amino-group in the acyl amino-acids is " neutralized " by the acyl groups;
they are therefore stronger acids than the simple amino-acids, and many of them
crystallize well. On the significance of acyl amino-acids to the structure of the
di- and poly-pep tides, see p. 391.
(6) Separation of optical components from racemic mixtures is brought about
through the strychnine, brucine, morphine, or cinchonine salts of the benzoyl-
and formyl-amino acids. The resolution of racemic alanine, a-amino-butyric
acid, o-amino-isovaleric acid, leucine, aspartic acid, and glutaminic acid, has
been carried out in this manner (B. 32, 2451 ; 33, 2370 ; 38, 3997). The resolu-
tion of the racemic synthetic a-amino-acids is of importance because it completes
the laboratory production of the natural a-amino-acids (from proteins), which
are all optically active. The resolution can also be carried out by the aid of
yeasts, which consume either the rf-form only, or only the /-form (C. 1906, II. 501 ).
(7) Amino-acids with alkyl groups attached to the nitrogen are obtained from
the monohalogen fatty acids or from hydroxy-acid nitriles by the action of
amines (J. pr. Ch. [2] 65, 188) :
NH(CH3)2 NYfR ^ /PTT ^ M NH(CH3)
CH.C1COOH - > CHa<£^Hs), - * (CH»^>C
(8) Continued methylation causes the amino-group to leave the molecule,
whereby unsaturated acids result. Thus, a-aminopropionic acid yields acrylic
acid ; a-aminobutyric acid gives rise to crotonic acid (B. 21, R. 86) ; o-amino-
n- valeric acid yields propylidene acetic acid (B. 26, R. 937).
(9) Hydriodic acid at 200° causes the exchange of the amino-group for
hydrogen, whereby the acid is converted into a fatty acid (B. 24, R. 900).
(10) Boiling with alkalis does not affect the amino-acids, but fusion with
potassium hydroxide causes decomposition into ammonia or amines and salts
of fatty acids.
(n) Dry distillation, especially in presence of barium oxide, decomposes
the acids into amines and COa :
Ethylamine.
(12) Nitrous acid converts the amino-acids into hydroxy-acids I
(13) The amino-ester hydrochlorides are changed by potassium nitrite into
diazo-fatty esters (p. 403), the formation of which serves for the detection of small
quantities of amino-acids (B. 17, 959). In the presence of excess of hydrochloric
acids, chloro-fatty acids are formed (C. 1901, I. 98). Similarly, nitrosyl bromide
produces a-bromo-fatty acids.
Ferric chloride produces a red coloration with all the amino-acids, which is
destroyed by acids.
Reduction of amino-esters produces ammo-aldehydes (B. 41, 956) ; oxidation
with HaOa, see C. 1908, 1. 1164.
NITROGEN DERIVATIVES OF THE HYDROXY-ACIDS 385
One of the chief characteristics of the a-amino-fatty acids is that
when they lose water they yield cyclic double acid amides correspond-
ing with the cyclic double esters of the alpha-hydroxy-acids or lac-
tides.
Glycollide. Glycocoll Anhydride.
The y- and 8-amino-acids, and amino-acids possessing long chains, however,
are capable of forming cyclic, simple acid amides, the lactams, corresponding with
the lactones, the cyclic, simple esters of the hydroxy-acids :
CHjCO v CH2CO v
>0 >NH
CH2CH/ CH2CH/
Butyrolactone. y-Butyrolactam,
Pyrrolidone.
S-Valerolactone. 8-Valerolactam,
a-Oxopiperidiue.
a-Amino-fatty Acids.
Glycocoll, Glycin, Amino- acetic Acid [Ammo-ethane Acid],
COOH coo
or I I , m.p. 232-236°, is obtained by the general methods
Ct^NH^ Ct^NH^
of preparation (pp. 381, 382) : (i) From monochloracetic acid and
ammonia (di- and triglycolamidic acids being formed at the same time) ;
or by warming monochloracetic acid with dry ammonium carbonate
(B. 16, 2827 ; 33, 70) ; (2) from phthalyl glycocoll ester (B. 22, 426) ;
(3) by the reduction of nitro-acetic acid ; (4) of cyanoformic acid ;
(5) by heating methylene amino-acetonitrile with hydrochloric acid,
when it changes to the hydrochloride of glycine ester (B. 29, 762) ;
(6) from methylene cyanhydrin, the product obtained by the union
of formaldehyde and hydrocyanic acid. Ammonia converts it into
glycocoll nitrile, which is converted into glycocoll by boiling barium
hydroxide solution (A. 278, 229 ; J. pr. Ch. [2] 65, 188) :
HNC rM NH, rN- rn TT
CH.O- ->CH2<N- -4-CH, - tOfc'
Glycocoll may be prepared by methods I, 2, 5, and 6, or by the
decomposition of hippuric acid (see below). A rather striking forma-
tion of glycocoll is observed (7) by conducting cyanogen gas into boiling
hydriodic acid :
CN.CN+2HaO+2H2=HOOC.CHaNHa+NHt ;
and, further, (8) by allowing ammonium cyanide and sulphuric acid to
act on glyoxal, when the latter probably at first yields formaldehyde
(B. 15, 3087) ; (9) from glyoxylic acid (p. 388) by the action of
ammonia, with the intermediate formation of formyl glycocoll (B. 35,
2438).
History and Occurrence. — Braconnot (1820) first obtained glycocoll by decom-
posing glue with boiling sulphuric acid. It owes its name to this method of forma-
tion and to its sweet taste : y\vKvs, sweet, n6\\a, glue.
VOL. I, 2 C
386 ORGANIC CHEMISTRY
Dessaignes (1846) showed that glycocoll was formed as a decomposition
product when hippuric acid was boiled with concentrated hydrochloric acid :
COOH COOH
-fHjO-r-HCl = | +C,H6COOH.
CH2NH.COC.H8 CH.NH..HC1
Hippuric Acid Glycocoll Benzoic Acid.
Benzoyl Glycocoll. Hydrochloride.
Strecker (1848) observed that glycocoll appeared from an analogous decompo-
sition of the glycocholic acid occurring in bile (comp. taurine, p. 326) ;
COOH COOK
| + 2KOH - | + C14H,906K + H20.
CH2NH2.C24H8904 CH2NH,
Glycocholic Acid. Potassium Potassium
Amino-acetate. Cholate.
Since then, glycocoll has been found to constitute the break-down product
of many other animal and vegetable proteins ; it is especially abundant in the
fibroin of silk.
Glycocoll was first (1858) prepared artificially by Perkin and Duppa, when
they allowed ammonia to act on bromacetic acid.
Properties. — Glycocoll crystallizes from water in large, rhombic
prisms, which are soluble in 4 parts of cold water. It is insoluble in
alcohol and ether. It possesses a sweetish taste, and melts with de-
composition. Heated with barium hydroxide it breaks up into methyl-
amine and carbon dioxide ; nitrous acid converts it into glycollic
acid. Ferric chloride imparts an intense red coloration to glycocoll
solutions ; acids discharge this, but ammonia restores it.
Metallic Salts. — An aqueous solution of glycocoll will dissolve many metallic
oxides, forming salts. Of these, the copper salt, (C2H4NOa)aCu+H2O, is very
characteristic, and crystallizes in dark blue needles : silver salt, C2H4NO2Ag,
crystallizes on standing over sulphuric acid. The combinations of glycocoll
with salts, e.g. C2H6NO2.KNO3, C2H6NO2.AgNO3, are mostly crystalline.
Ammonium Salts. — Glycocoll yields the following compounds with hydro-
chloric acid : C2H6NO2.HC1 and 2(C2H5NO2).HC1. The first is obtained with
an excess of hydrochloric acid, and crystallizes in long prisms : nitrate, C2H5NO2-
HNO8, forms large prisms.
Amino-acetic Ethyl Ester, Glycocollic Ester, NH2.CH2COOC2H8, b.p. 149°,
b.p. 10 52°, is an oil resembling cocoa in odour, which is easily soluble in ether,
alcohol, and water. In aqueous solution, however, it changes into di-aci-pipera-
zine (p. 391), and in ether into tri-glycyl-glycine ester (p. 392). The ester is
particularly suitable for the preparation of various derivatives of glycocoll (B. 34,
436). Glycocollic Ester Hydrochloride, HC1.NH2.CH2COOC2H8, m.p. 144°, is
formed by the passage of HC1 gas into a mixture of alcohol and glycocoll, and
can be employed as a method of estimation of glycocoll on account of its slight
solubility in alcoholic hydrochloric acid (B. 39, 548). It is also obtained from
methylene-amino-acetonitrile (see below), aceturic acid (p. 388) (B. 29, 760), or
from the reaction product of hexamethylamine and potassium chloroacetate
(C. 1899, I. 183, 420), by the action of alcoholic hydrochloric acid, whereby the
ester hydrochloride results. This is also formed by pouring excess of alcohol on
Glycyl Chloride Hydrochloride, HCl.NHaCH2COCl, which is prepared from pre-
cipitated glycocoll and phosphorus pentachloride in acetyl chloride, as a crystal-
line powder (B. 38, 2914).
Glycocollamide, Amino-acetamide, NHaCH2CONHa, is produced when
glycocoll is heated with alcoholic ammonia to 160°. It is a white mass which
dissolves readily in water, and reacts strongly alkaline. The HCl-salt results
on heating chloracetic ester to 70* with alcoholic ammonia.
. Glycocoll Hydrazide, NH2CH2CO.NHNH2, m.p. 80-85*, is obtained from
glycocoll ester and hydrazine hydrate, as a hygroscopic crystalline mass ; hydro-
chloride, C2H7N,O.2HC1, m.p. 201* (J. pr. Ch. [2] 70, 102).
Glycocoll Nitrile, Amino-acetonitrile, NHaCHaCN, b.p.1$ 58°, is prepared from
glycoll nitrile and alcoholic ammonia at oe ; hydrochloride, m.p. 165°; sulphate,
C2H4Na.H,SO4, m.p. 101° (J. pr. Ch. [2] 65, 189; B. 36, 1511).
NITROGEN DERIVATIVES OF THE HYDROXY-ACIDS 387
Methylene Amino-acetonitrile, CH2=NCH2CN, m.p. 129°, with decomposition,
is formed from formaldehyde, ammonium chloride, and potassium cyanide ;
also from glycocoll nitrile and formaldehyde. It may consist of a double molecule.
It is remarkable for its crystallization (J. pr, Ch. [2] 65, 192 ; B. 36, 1506).
COOH COO
Methyl Glycocoll, Sarcosine, \ or | \ , m.p. 210-220*
CH2NHCHt CH2NH2CH,
with decomposition, was first obtained by Liebig (1847) as a decomposition
product of the creatine contained in beef extract. Its name is derived from
o-op£, flesh. Volhard (1862) prepared it synthetically by the action of methyl-
amine on monochloracetic acid ; and it is also produced when creatine or
CO,H NHj
methyl glycocyamine, I i or caffeine is heated with barium
CH2N(CH3).C=NH
hydroxide solution. It dissolves readily in water but with difficulty in alcohol.
The nitrile of sarcosine is obtained together with methylamine from methylene
cyanhydrin, the additive product of formaldehyde and hydrocyanic acid (A. 279,
39 ; J. pr. Ch. [2] 65, 188). When melted it decomposes into carbon dioxide
and dimethylamine, yielding at the same time sarcosine anhydride (p. 392).
It forms salts with acids, which show an acid reaction. Ignited with soda-lime
it evolves methylamine. Sarcosine yields methyl hydantoin with cyanogen
chloride and creatine (q.v.) with cyanamide. Sarcosine Ethyl Ester, CH3NHCH2-
CO2C2H6, b.p.10 43° (B. 34, 452).
Dimethyl Glycocoll, (CH3)2NCH2COOH, is prepared by the hydrolysis of its
nitrile, dimethylamino-acetonitrile, (CH3)2NCH2CN, b.p. 138°. This is formed by
the action of dimethylamine on methylene-amino-acetonitrile (above) or on
glycollic nitrile. Dimethylamino-acetic Methyl Ester, (CH3)2NCH2COOCH3, b.p.
135°, is obtained from the interaction of chloracetic acid and dimethylamine.
It is isomeric with betaine, into which it changes when heated. Betai'ne, on tha
other hand, when heated above its melting point (293°) is isomerized to a large
extent into dimethyl ammo-acetic methyl ester (B. 35, 584) :
(CH3)2NCH2COOCH8 •<-> (CH3)8NCHaCoi.
COO
Trimethyl Glycocoll, Betaine, Oxyneurine, Lycine, | \ , has already
CH2N(CH3)8
been mentioned (p. 330) in connection with choline, from which it is prepared by
oxidation.
Its hydrochloride is prepared by the union of monochloracetic acid with
trimethylamine (B. 2, 167 ; 3, 161 ; 35, 603) :
C1CH2COOH+N(CH3)3=C1N(CH8)3CH2COOH.
Similarly, chloroacetic ester and trimethylamine yield Betaine Ester Hydro-
chloride, C1N(CH3)3CH2.CO2C2H5, m.p. 143° (B. 38, 167). Betaine is also obtained
by the methylation of glycocoll by means of methyl iodide, potassium hydroxide,
and methyl alcohol. It occurs in beet-root (Beta vulgaris) (Scheibler, B. 2, 292 ;
3, 155), and is to be extracted from the " melasse" of the beet-sugar factory, in
which it is the substance which gives rise to the trimethylamine obtained there-
from (p. 165). It also occurs in the leaves and stalks of Lycium barbarum, in
cotton seeds, and in germ of malt and wheat (B. 26, 2151).
It crystallizes in deliquescent crystals in which the acid, HON(CH3)3CH2COOH,
may be present. At 100° this ammonium hydroxide derivative loses one molecule
of water, forming a cyclic ammonium salt, ON(CH8)3CH2CO, m.p. 293°, with
conversion into dimethyl amino-acetic methyl ester (see above). Iodine in
potassium iodide precipitates a periodide from an aqueous solution of betaine
(C. 1904, II. 950).
The action of ethylamine, diethylamine and triethylamine on chloracetic
acid produces ethyl glycocoll, diethyl glycocoll, and triethyl glycocoll, triethyl betaine,
(CjH6)3NCH2COO. Similarly to betaine itself, the latter compound is converted
by destructive distillation into diethylamine acetic ethyl ester, b.p. 177°, the iodo-
ethyloxide of which is reconverted by silver oxide into triethyl betaine. Similar
changes have been observed with dimethyl ethyl betaines and methyl diethyl betaine
388 ORGANIC CHEMISTRY
(B. 35, 584). The homologous betaines can also be prepared by the addition of
iodo-alkyls to dialkylamine acetonitriles and the subsequent saponification of
the iodo-alkylate formed. The dialkylamino-acetonitrilef just referred to can be
synthesized from formaldehyde, hydrocyanic acid, and dialkylamines (B. 36,
4188).
(C2H8)2NCHaCN -^> (CaH6)aN(CH8I)CH2CN > (C2H6)2N(CHS)CH2COO.
Formyl Glycocoll, Formamine Acetic Acid, HCONH.CH2COOH, m.p. 151-
152°, is prepared by heating glycocoll with formic acid to 100°; and from glyoxylic
acid and ammonia (B. 36, 2525 ; 38, 3999)-
2CHO.COOH+NHa=HCO.NH.CH2COOH+CO2+HaO.
Glyoxylic Acid. Formyl Glycine.
Acetyl Glycocoll, A cetamine A cetic A cid, Aceturic ^ad,CH3CONH.CH2COOH,
m.p. 206°, results from the action of acetyl chloride on silver glycocoll ; from
acetamide and monochloracetic acid ; from ammonia and a mixture of glyoxylic
and pyroracemic acids (B. 36, 2526). It is readily soluble in water and alcohol,
and behaves like a monobasic acid (B. 17, 1664).
More important are hippuric acid or benzoyl glycocoll (q.v.) and glycocholic
acid (q.v .) which have already been referred to in connection with glycocoll, and
which will be dealt with later. They are similarly constituted to aceturic acid.
Naphthalene Sulphoglycine, C10H7SO2NH.CH2COOH, m.p. 156° (B. 35, 3779).
Iminodiacetic acid and nitrilotriacetic acid bear the same relation to glycocoll
that di- and trihydroxy-ethylamine sustain to hydroxy-ethylamine :
NH2CH2CO8H NH(CHa.CO2H)2 N(CH2.CO2H)3
NH2CH2CH8OH NH(CH?CH2OH)a N(CH2CH2OH)8.
These compounds are formed on boiling monochloracetic acid with concen-
trated aqueous ammonia (A. 122, 269 ; 145, 49 ; 149, 88).
Iminodiacetic Acid, NH(CH2CO2H)2, m.p. 225°, forms salts both with acids
and bases, whilst Nitrilotriacetic Acid, N(CH2CO2H)S, cannot unite with acids.
Imino-acetonitrile, NH(CH,CN)2, m.p. 75°, and Nitrilo-acetonitrile, N(CH2CN)S,
m. p. 126°, are obtained from methylene cyanhydrin and ammonia (A. 278, 229 ;
279, 39). Dimethyl Dicyano-methyl Ammonium Bromide, (CH?)2NBr(CH2CN)a,
is prepared from dimethylamino-acetonitrile and bromacetonitrile (B. 41, 2123).
Alanine, a-Aminopropionic Acid, CH3CH(NH2)C02H, or CH3CH-
I I
(NH3)COO, m.p 293° with decomposition on being rapidly heated,
is derived from a-chloro- and a-bromo-propionic acid by means of
ammonia ; also from aldehyde-ammonia, hydrocyanic acid, and hydro-
chloric acid ; or aldehyde, ammonium cyanide, and hydrochloric acid
(B. 41, 2061), by hydrolysis of the intermediate a-amino-propioni-
trile, CH3CH(NH2)CN. This can be precipitated as sulphate from an
alcoholic solution of aldehyde-ammonia and hydrocyanic acid by
sulphuric acid, and may be resolved into its optically active components
by formation of the tartrates (p. 384) (C. 1904, I. 360).
Synthetic alanine, of which the name refers to its connection with aldehyde-
ammonia, is the racemic or [d+l] form of a-amino-propionic acid. It crystallizes
from water in aggregates of hard needles ; it is soluble in 3 parts of water, less
easily in alcohol, and not at all in ether. On being quickly heated, it melts
with partial decomposition, partially into ethylamine and CO2, and partially
into aldehyde, CO, and ammonia (B. 25, 3502 ;" 32, 245). Alanine Ethyl Ester,
CH3CH(NH2)C09C2H5, b.p.n 48° ; hydrochloride is easily soluble in alcohol,
contrary to glycine ester hydrochloride (B. 34, 442). Alanine Chloride Hydro-
chloride, CH3CH(NH8C1)COC1, is a white crystalline powder (B. 38, 2917).
^-Naphthalene Sulpho-alanine, C10H7SO2.NHCH(CH8)COOH, m.p. 152°.
Benzoyl Alanine, C6H6CO.NHCH(CH3)COOH, m.p. 165°, is resolved by means
of brucine into the components [d- and /]- benzoyl alanine, which, on hydrolysis,
yield /- and ^-alanine.
d-Alanin also occurs as a product of hydrolytic decomposition of many
proteins ; from fibroin of silk it is obtained by means of its ester. It forms
NITROGEN DERIVATIVES OF THE HYDROXY-ACIDS 389
rhombic crystals, which decompose at 297°. In aqueous solution its rotatory
power is small, [a]^=+2'70 ; in hydrochloric acid solution it is much greater,
[a]^= + io-40 (B. 39, 462 ; 40, 3721).
Nitrous acid converts ^-alanine into the ordinary rf-lactic acid (p. 364) ; on
the other hand, nitrosyl bromide (p. 384) changes d-alanine into /-bromopro-
pionic acid, which with ammonia yields /-alanine. This, with nitrosyl bromide,
gives d-bromopropionic acid, which ammonia converts into rf-alanine (Walden's
inversion, p. 364 ; B. 40, 3704). tf-Alanine is also obtained by the reduction,
with sodium amalgam, of /-fl-chloralanine, C1H2CH(NH2)COOH. The ester
of this acid is obtained from /-serine ester (/Mrydroxy-a-aminopropionic ester)
and PC15; since /-serine can be converted into d-glyceric acid and this into /-tartaric
COOH
acid, the formula of <f-alanine must be NH, — C — CH, (B. 40, 3717) (see also
H
the considerations on the configuration of the carbohydrates).
lodomethane and sodium hydroxide solution convert <£-alanine into l-Trimethyl
Propionic Betaine, (CH3)3NCH(CH3)COO, which also results from the interaction
of d-a-bromopropionic acid and trimethylamine (B. 40, 5000). Triethyl Propionic
Betaine is formed by hydrolysis of the iodo-ethylate of Diethylaminopropionitrile,
(C2H6)2NCH(CH3)CN, b.p.,7 81°, the reaction product of lactic acid nitrile and
diethylamine (B. 36, 4188).
pTT p-TT
Iminodipropionic Acid, HocO>CH~ NH~ CH<COOH' contains two
asymmetric carbon atoms, giving rise to two optically inactive forms, m.p. 255°,
corresponding with meso tartaric acid, and m-.p. 235°, corresponding with racemic
acid. The monamides, m.ps. 332° and 210°, are formed by the prolonged inter-
action of dilute hydrocyanic acid and aldehyde-ammonia at ordinary tempera-
tures, together with iminodipropionintide, NH[CH(CH3)CO]2NH, m.p. 186°,
alanine, and other substances (B. 39, 3942).
Higher homologues of a-amino-aeids are prepared mainly by the general
methods (i) from a-halogen-fatty acids and (5) from the nitriles of a-hydroxy-
acids and ammonia. »
a-Amino-n-butyric Acid, CH3CN2CH(NH2)COOH, m.p. 307° with decomposi-
tion, is resolved by means of the morphine salt of the benzoyl-derivative, d-acid
[a]^=+8°, /-acid ra]£0=-7-90; ethyl ester, b.p.n 61° (B. 33, 2387; 34, 443);
nitrile (B. 41, 2062). a-Amino-isobutyric Acid, (CH3)2C(NH2)COaH, sublimes at
280° without melting, and is formed also by oxidation of diacetonamine sulphate ;
nitrile, b.p.12 50°, is prepared from acetone and ammonium cyanide (B. 33,
1900; 39, 1181, 1726). a-Amino-valeric Acid, CH3[CHa]8CH(NH2)COOH, is
formed also by oxidation of benzoyl coniine (B. 19, 500) ; ethyl ester, b.p.8 68°
(B. 35, 1004). «
a-Amino-isovaleric Acid, V aline, Butalanine, (CH3)2CHCH(NH2)COOH,
decomposes 298°. The inactive acid results from o-bromisovaleric acid and
ammonia; ethyl ester, b.p.8 63°. Formyl V aline, HCONHCH(C3H7)COOH,
m.p. 140-145°, is produced by heating valine and formic acid together. It is
resolved by means of its brucine salts, the /- and tf-formyl valine, yielding l-V aline
ind d-Valine. The latter, m.p. 315°, [a]^=+6'42°, in aqueous solution and
+28-8° in hydrochloric acid, is a decomposition product of protein bodies
— in the germs of the lupin, horn, casein, from protamines, and from the pancreas
)f oxen. /-Valine has a much sweeter taste than d- valine (B. 39, 2320). a-Amino
Methyl Ethyl Acetic Acid, (C2H6)(CH8)C(NH2)COOH, is prepared from methyl
2thyl ketone, etc. ; ethyl ester, b.p.,0 66° (B. 35, 400 ; 39, 1189).
o-Aminocaprolc Acids. a-Amino-n-caproic Acid, CH3[CH2]3CH(NHa)COOH,
s prepared from a-bromo-n-caproic acid and ammonia. It is resolved into
ts optical component by means of its 6ew^oy/-derivative (B. 33, 2381 ; 34, 3764)«
a-Amino-isocaproic Acids. Leucine.— (CH3) 2CHCH2CH(NH2)COOH,
)ptically active leucine. Leucine (from XOJKOS, glistening white,
•eferring to the appearance of the scaly crystals) occurs in different
inimal fluids, in the pancreas, in the spleen, in the lymph-glands, and
3go ORGANIC CHEMISTRY
is physiologically very important. It is formed by the decay of pro-
teins, or when they are boiled with alkalis and acids. It is prepared
by heating horn, the dried cervical ligament of oxen, or from casein
with dilute sulphuric acid. Its purification is best effected by conver-
sion into the ester (B. 34, 446 ; C. 1908, I. 1633). Leucine is also
obtained from vegetable proteins such as that of the lupin. Strecker
(1848) showed that when it was treated with nitrous acid it passed into
a hydroxycaproic acid, leucic acid, m.p. 73°, p. 366.
The naturally occurring leucine, m.p. 270°, sublimes unaltered when carefulty
heated, but decomposes on rapid rise of temperature into amylamine and CO2.
It forms shining leaflets, which feel greasy to the touch. It is soluble in 48 parts
of water and 800 parts of hot alcohol. It is optically active, the free acid rotating
the plane of polarization to the left, whilst its hydrochloride rotates it to the right.
When heated with alkalis it becomes inactive and is then identical with that
synthesized from isovaler aldehyde, ammonium cyanide, and hydrochloric acid ;
or by decomposing the condensation product of isobutyraldehyde and hippuric
acid (A. 316, 145) :
NH4NC /NHa NH3 C8H6C:N v
(CH^CHCHaCHO > (CH8)2CHCH,CH<( •<- >C
N:OOH o.ccx ||
(CH3)2CHCH
The resolution of the rac.-6^M^y/^Mctw5,(CH3)2CHCH2CH(NHCOC(lH6)COOH,
by means of cinchonine produces benzoyl d-leucine (laevo-rotatory) and benzoyl
l-leucine (dextro-rotatory), from which hydrolysis liberates d-leucine (dextro-
rotatory), and l-leucine (laevo-rotatory) identical with the naturally occurring
substance. It is more convenient to resolve by means of \d-\- F]-formyl leucine,
HCO.NHCH(C4H9).COOH (B. 38, 3997). ^-Leucine is also obtainable from
/-leucine by Penicillium glaucum ; its hydrochloride is lasvo-rotatory (B. 24,
669 ; 26, 56 ; 33, 2370). Leucine Ethyl Ester, b.p. 196°. Acetyl Leucine, m.p. 160°
(B. 34, 433). Leucine Chloride Hydrochloride, C4H9CH(NH3C1)COC1 (B. 38, 615).
a-Amino-sec.-butyl Acetic Acid, Isoleucine, C^5>CH.CH(NH2)COOH, con-
tains 2 asymmetric carbon atoms, and therefore gives rise to 4 optically active
components and 2 racemic forms. A d-isoleucine, m.p. 280°, with decomposition,
[a]D°=+9'7 in water, +36*8 in hydrochloric acid, occurs together with leucine
in beet-root melasse, and as a decomposition product of proteins. Synthetically,
rac.-isoleucine is produced by reduction of a-hydroximino-isobutyl acetic acid
(p. 410), and from a-bromo-sec.-butyl acetic acid and ammonia. ^-Isoleucine is
prepared from ^-valeric aldehyde by the cyanhydrin synthesis (B. 40, 2538 ; 41,
1453)-
a-Amino-csnanthic Acid, CH8[CH2]4CH(NH2)CO2H (B. 8, 1168). a-Amino
caprylic Acid, CH3[CH2]5CH(NH2)CO2H (A. 176, 344). a-Aminopalmitic Acid,
CH3[CH2]13CH(NH2)C02H (B. 24, 941). a-Aminostearic Acid, CH8[CH2]15CH-
(NH2).COaH, m.p. 221° (B. 24, 2395).
As has repeatedly been mentioned, the simple a-amino-acids, such
as glycocoll, alanine, valine, and leucine, occur together, and also with
such complicated substances as serine, proline, cystine, asparagine,
lysine, arginine, histidine, and tyrosine, as products of the hydrolytic
decomposition of proteins. It is probable that these breakdown
bodies are united with one another in the protein molecule through their
amide groups.
This question has been attacked both synthetically and analytically
(E. Fischer : Untersuchung iiber Amino-sauren, Polypeptide und Pro-
teine, Berlin, 1906 ; Th. Curtius : Verkettung von Amino-sauren) (J.
pr. Ch. [2] 70, 57). In synthesis, the esters, chlorides, and azides of
NITRC
ITROGEN DERIVATIVES OF THE HYDROXY-ACIDS 391
the arninocarboxylic acids themselves or of the substances which go
to produce them, have been employed; and by their means the
aminacyl residue has been substituted into the ammo-group of other
amino-acids, and the process has been successively repeated. The
aminacyl arninocarboxylic acids produced have been named by E.
Fischer, peptides because of their comparability with the natural pep-
tones (protein products of digestion) . They are classified according to
the number of the connected amino-acids — di-t tri-, telra-peptides, etc.
I. Dipeptidcs and their inner anhydrides, cyclic double amides, ay-
Dioxopiperazincs. a- Ammo-esters, when heated or even on standing
in aqueous solution, part with alcohol and form dimolecular cyclic
amides, corresponding with the lactides (p. 385) :
The fundamental substance, to which such compounds can be
referred as being oxygen substitution products, is diethylene diamine
or piper azine (p. 336), whence the names ay-diketo-, diaci-, or dioxo-
piperazine :
Diglycollide. «y-Dioxopiperazine. Piperazine.
When warmed for a short time with hydrochloric or hydrobromic acid, or
when shaken with dilute alkalis, the dioxopiperazine is split up into the dipeptide,
which when melted, or when its ester is heated, easily changes into the dioxo-
piperazine :
NH<fC°— CH*NNH _> HOCO— CH2. „
N:H2— CO^ H-<— ~H2NCH2— CO>NH>
oy-Dioxopiperazine. Glycyl Glycine
(the simplest dipeptide).
Unsymmetrically substituted dioxopiperazines, such as leucyl glycine
anhydride, can be split into two different dipeptides, from which the same
anhydride can be reformed.
2. Dipeptides and polypeptides are obtained in the following
manner : — (a) Chlorides of the a-halogen fatty acids react with
a-amino-acids to form a-halogen acylamino-acids, which with am-
monia give dipeptides. These by further treatment with a-halogen
acyl chlorides and ammonia yield tripeptides, and these tetrapep tides,
pentapeptides, and so on :
NH,
C1CH2CO.NHCH2COOH - > NH2CH2CO.NHCH2COOH - >
Chloracetyl Glycine. Glycyl Glycine.
NH,
C1CH2CO.NHCH2CO.NHCH8COOH - >
Chloracetyl Glycyl Glycine.
NHaCH2CO.NHCH2CO.NHCH2COOH.
Diglycyl Glycine.
The esters of the halogen acylamino-acids are easily converted by ammonia
into dipeptide anhydrides, dioxopiperazines (see above).
(6) Again, the halogen-acyl-amino acids can be converted into their chlorides,
united with other amino-acids and then be acted on by ammonia :
C4H,CHBrCO.NHCH2COCl - >•
Bromisoctproyl Glycine Chloride.
C4H,CHBrCO.NHCH2CO.NHCH2COOH
Bromisocaproyl Glycyl Glycine.
NH
Leucyl Glycyl Glycine.
392 ORGANIC CHEMISTRY
(c) Finally, the chlorides of the amino-carboxylic acid hydrochlorides can be
employed with advantage (p. 383). The azides, also, of the acyl amino-acids
such as hippuryl azide, C6H6.CONHCH2CON8> unite with amino-acids, splitting
off N3H, and easily forming acyl derivatives of the di- and polypeptides.
3. Higher polypeptides result from heating the methyl esters of lower peptides :
2NH2CH2CO.NHCH2CO.NHCH2C02CH3 - >
Diglycyl Glycme Ester. NH2CH,CO.[NHCH2CO]4NHCHaCOaCH,.
Pentaglycyl Glycine Ester.
4. Analytically, some di- and polypeptides have been produced by the partial
hydrolysis of proteins, such as silk fibroin, elastin, gliadine, gelatin, by means of
cold fuming hydrochloric acid ; or by tryptic digestion, as, for instance, glycyl
alanine, alanyl leucine, alanyl diglycyl tyrosine (?) (B. 40, 3544)-
Properties. — Di- and polypeptides are mostly soluble in water ; less soluble
are, for instance, the penta- and hexa-peptides of glycocoll, which are, however,
soluble in acids and alkalis, showing that the amino-acid character is preserved.
The peptides are mostly insoluble in alcohol. They decompose, with or without
melting, above 200°, the dipeptides forming mostly dioxo-piperazine.
The " biuret reaction " — a red or violet coloration with an alkaline solution
of copper sulphate — which is characteristic for the naturally occurring proteins,
is given by many of the higher artificial peptides, such as Curtius' biuret base
(triglycyl glycine ester).
The behaviour of di- and poly-peptides with pancreatic juice is of importance,
since some are hydrolyzed by it and some are not, e.g. [fl?+f]-alanyl glycine is
split up, yielding rf-alanine and glycine, whilst glycyl alanine is not. All peptides
are completely hydrolyzed by hydrochloric acid.
Glycyl Glycine, NH2CH?CO.NHCH2COOH, decomposes 215-220°; ethyl
ester, m.p. 89°, easily parts with alcohol, yielding
Glycine Anhydride, Diglycolyl Diamide, ay-Dioxopiperazine, ay-Diacipipera-
zine, NHCH2CO.NHCH2CO, m.p. 275°, is also easily prepared from glycocoll
ester in aqueous solution. By boiling for a short time with strong hydro-
chloric acid or by shaking with w/x sodium hydroxide, it is easily split up into
glycyl glycine (B. 38, 607). Sarcosine Anhydride, CH3NCH2CON(CH3)CH2CO,
m.p. 150°, b.p. 350°, is obtained by heating sarcosine (B. 17, 286).
Glycyl [d+[]- Alanine, NH2CH2CO.NHCH(CH3)COOH, m.p. 227° with decom-
position, is prepared from chloracetyl alanine and ammonia ; anhydride, m.p.
245° with decomposition, is formed from chloracetyl alanine ester and ammonia.
Glycyl d- Alanine and its anhydride are obtained by the hydrolysis of silk
fibroin (B. 40, 3546). d- Alanyl Glycine, CH3CH(NH2)CO.NHCH2COOH, m.p.
235° with decomposition, is produced from tf-alanyl chloride hydrochloride and
glycocoll ester (B. 38, 2914).
Alanyl Alanine, CH3CH(NH2)CO.NHCH(CH3)COOH, m.p. 276° with decom-
position, is obtained by the decomposition by alkali of its anhydride. Di-lactyl
Di-amide, Lactimide, NH<^Q >NH, m.p. 275°. The anhydride is best
obtained from alanine ester at 180°. It is reduced by sodium and alcohol to
08-dimethyl piperazine (B. 38, 2376; C. 1902, I. 631). l-A lanyl d-Alanine is
produced from /-bromopropionyl d-alanine and ammonia, [a]%=— 68-5° ; its
ester on parting with alcohol is converted into the optically inactive meso-anhydride
(see Introduction, p. 32).
a-Aminobutyryl a-Aminobutyric Acid, NH2CH(C3H7)CO.NHCH(C3H7)COOH,
stereoisomenc forms, m.p. 273° with decomposition, and m.p. 257° with decom-
position, is prepared from bromobutyryl aminobutyric acid ; anhydride, m.p.
207 (A. 340, 187).
Leucyl Leucine, NH2CH(C4H9)CONHCH(C4H9)COOH, m.p. 270° with decom-
position, is formed from bromisocaproyl leucine and ammonia ; anhydride leu-
c^n^m^de, m.p. 271 , is prepared from leucine ester (B. 37, 2491).
Diglycyl Glycine, NH2CH2CO.NHCH2CO.NHCH2COOH, m.p. 246° with
decomposition is prepared from chloracetyl glycyl glycine and ammonia ; methyl
ter, m.p in when heated passes into pentaglycyl glycine ester, slightly soluble
in water (t>. do 472).
NITROGEN DERIVATIVES OF THE CARBOXYLIC ACIDS 393
Triglycyl Glycine is prepared from chloracetyl diglycyl glycine ; ester,
NH2CH2CO.NHCHaCO.NHCH2C9.NHCH2COOC2H$, the " biuret base," is
formed together with a little glycine anhydride, when glycocoll is left to stand in
solution in absolute ether. Benzoyl Triglycyl Glycine, m.p. 217°, is formed also
from hippuryl glycine azide and glycyl glycine (B. 37, 1284 ; 2486).
Leucyl Pentaglycyl Glycine, C4H,CH(NH,)CO[NHCHaCOJ6NHCHaCOOH, is
prepared from bromisocaproyl pentaglycyl glycine and ammonia (B. 39,
461).
jS-AMINOCARBOXYLIC ACIDS
Of this group of substances little is known. They form neither cyclic double
amides, as do the a-amino-acids, nor cyclic simple amides or lactams like the
higher ammo-acids, except beta'ine.
fi-Aminopropionic Acid, fi-Alanine, CH2(NH2)CH2.COOH, m.p. 196° with
decomposition into ammonia and acrylic acid. It is isomeric with alanine
(p. 388), and is prepared from jS-iodopropionic acid and ammonia, from /J-nitro-
propionic acid, from isoserine (a-hydroxy- jS-aminopropionic acid) by reduction
with hydriodic acid and phosphorus (B. 35, 3796) ; but most conveniently from
CHj.CCX
succimide, | /NH, by the Hofmann inversion (p. 159) by means of bromine
CH2.CCK
and alkali (B. 26, R. 96 ; C. 1905, I. 155 ; 1906, I. 818) ; methyl ester, b.p.u
58° ; amide, m.p. 40° ; fi-Dimethylamine Propionic Methyl Ester, (CH8)2NCHt-
CHaCOOCH3, b.p. 154°, is prepared from j3-iodopropionic ester and dimethyl-
amine. Heat partially transforms it into its isomer fi-Trimethyl Propiobetatne,
(CH3)3NCH2CH2COO, which in its turn undergoes transformation on melting
into trimethylamine acrylate, CH2:CHCOONH(CH3)8 (B. 35, 584).
fi-Aminobutyric Acid, CH3CH(NH2)CH2CO2H, m.p. 156° (approx.), is prepared
by heating crotonic acid with ammonia. It is a very hygroscopic crystalline
mass (J. pr. Ch. [2] 70, 204). p-Amino-isovaleric Acid, (CH3)2C(NH2)CH,COOH,
is produced by the reduction of the corresponding nitro-acid (p. 382).
y-, 8-, €-, and £-Aminocarboxylic Acids.
The most important characteristic of the y- and 8-amino-carboxylic
acids as well as of some of the higher acids is that when heated they
part with water and yield cyclic, simple acid amides or lactams (p. 395).
(i) Piperidine derivatives, when oxidized, have yielded some of these acids
(Schotten). (2) Potassium phthalimide affords a general synthetic method:
ethylene bromide or trimethylene bromide, acted on by it, changes to o>-brom-
ethyl phthalimide and to-brompropyl phthalimide (Gabriel). These bodies, as
is known, have also been utilized in the preparation of hydroxalkylamines (p. 328).
In order to get y- and 8-amino-carboxylic acids by their aid they are caused to
react with sodium malonic ester and sodium alkyl malonic ester. The conden-
sation product resulting in this manner is decomposed on heating it with hydro-
chloric acid, into phthalic acid, y-, or 8-amino-carboxylic hydrochloride, carbon
dioxide and alcohol (B. 24, 2450) :
C.H
I
w-Bromethyl Phthalimide. w-Brompropyl Phthalimide.
•y-Aminobutyric Acid. 5-Aminovaleric Add.
Similarly, e-bromo-amyl phthalimide can be made to yield c-phthalimido-
imyl malonic ester, and this converted into £-aminoheptylic acid (B. 35, 1367).
394 ORGANIC CHEMISTRY
Or, benzoyl amino-amyl iodide (p. 365) may easily be made to react with potassium
cyanide or sodium malonic ester, the product from which is hydrolyzed.
(3) A general method for the preparation of 8-, e-, and ^-ammo-acids and their
lactams, is the transformation of the oximes of cyclic ketones, such as penta-,
hexa-, and hepta-methylene ketoximes (Vol. II.). These are converted by con-
centrated sulphuric acid into isoximes or lactams (comp. Beckmann's inversion,
p. 227) which can be decomposed into their respective amino-acids (Wallach,
A. 312, 171):
CH2.CH2V CH2.CH2.NH
| >C:NOH > | | ;
CH2.CH/ CH2.CH2.CO
CH2.CH2.C:NOH CH2.CHa.CH2
I I > \ >NH
CHa.CHa.CHt CH2.CHt.CO /
CHa.CH2.CH2v CH2.CH2.CH2.NH
| >C:NOH > | I
CH2.CH2.CH/ CH8.CH2.CH2.CO
For considerations on the course of these transformations and on the Becnmann
inversion generally, see A. 346, 27.
y-Aminobutyric Acid, Piperidic Acid, m.p. 183-184°. It is formed (i) when
piperidyl urethane, CH2<£^2£^2>N.COaCaH6, is oxidized with nitric acid
(B. 16, 644) ; (2) by means of potassium phthalimide ; either— (a) by the double
decomposition of bromethyl phthalimide with sodium malonic ester (see above),
or (b) from o>-bromopropyl phthalimide and potassium cyanide, and decomposing
the phthalyl y-aminobutyric nitrile (B. 23, 1772). The acid is most conveniently
obtained from its lactam (p. 395) by means of barium hydroxide solution (B. 33,
2230). y-Dimethyl Aminobutyric Methyl Ester, (CH3)2N[CH2]3COOCH3, b.p.
172°, is prepared from y-chlorobutyric ester and dimethylamine. On heating
it is decomposed into butyrolactone and trimethylamine. The isomeric y-Tri-
methyl Butyrobetatne, (CH8)3N[GH2]3COO, which is obtained by exhaustive
methylation of butyrolactam in alkaline solution (B. 35, 617) undergoes the same
decomposition.
y-Amino valeric Acid, CH3CH(NH2)CH2CH2CO2H, m.p. 193°, results from
the decomposition of phenylhydrazone Isevulinic acid by sodium amalgam (B. 27,
2313). Both y-amino-acids, when heated, pass into lactams.
8-Amino-n-Valeric Acid, Homopiperidic Acid, NH2(CH2)4CO2H, m.p. 158°,
is produced by the putrescence of fibrin, flesh, and gelatin (B. 31, 776).
The benzoyl derivative of this acid and also Sulpho-8-aminovaleric Acid,
SO2[NH(CH2)4CO2H]2, m.p. 163°, are formed by the oxidation of benzoyl piperi-
dine, CHa<£ga£g2>NCOC6H5, and of sulphopiperidine by KMnO4 (B. 21,
2240) ; the acid is prepared from phthalimido-propyl malonic diethyl ester
(B. 23, 1769).
By method 2 (p. 393) the following are also prepared : a-Methyl 8-Amino-n-
valeric Acid, NH2.CH2CH2CH2CH(CH3)CO2H, m.p. 168° ; a-Ethyl B-Amino-n-
valeric Acid, NH2CHtCH2CH2CH(C,H8)CO2H, m.p. 200-200-5°; a-Propyl 8-
Amino-n-valeric Acid, NHjCH^HjCHaCH^aH^COaH, m.p. 186° (B. 24, 2444).
A ft- Qiy-Methyl S-Amino-u-valeric Acid, m.p. 134°, with decomposition, is pre-
pared from its lactam (p. 396) (A. 312, 185).
8-Trimethyl Valerobetaine, (CH3),N[CH2]4COO, of which the hydrobromide is
obtained from y-bromopropyl malonic esters and trimethylamine, by hydrolysis,
and the action of hydrobromic acid. The substance itself is converted by heat
into the isomeric ^'Dimethylamine Valeric Methyl Ester, (CH3)2N[CHa]4COOCH3,
b.p. 186-189°, together with 8-valerolactone (B. 37, 1853).
8-Amino-n-octanic Acid, Homoconiinic acid, C3H7CH(NH2)[CH2]8CO?H, m.p.
158°. The benzoyl compound is obtained by oxidation of benzoyl conine with
KMn04 (B. 19, 504).
«-Aminoeaoroie Acid, c-Leucine, NH2[CH2]6CO2H, m.p. 204°, is obtained
NITROGEN DERIVATIVES OF THE CARBOXYLIC ACIDS 395
from phthalimidobutyl malonic ester, from e-benzoyl aminocapronitrile, C6H6-
CONH[CH2]6CN (B. 40, 1839), or from its lactam, the hexamethylene ketone-
isoxime, by boiling with hydrochloric acid. Similarly, various acids can be
prepared from their lactams, such as methyl e-aminocaproic acid and methyl
isopropyl e-aminocaproic acid. e-Aminocaproic acid is oxidized by permanganate
to adipic acid ; nitrous acid produces two isomeric hexenic acids instead of the
expected e-hydroxycaproic acid (p. 375) (A. 343, 44).
£-Amino-n-heptylic Acid, NH2[CH2]6COOH, m.p. 187° with decomposition,
is also prepared from its lactam, the isosuberone oxime (q.v.) ; also from the
phthalimido-amyl malonic ester, or benzoyl amyl aminomalonic ester (B. 40,
1840). On heating, it no longer yields a simple lactam (B. 35, 1369). Per-
manganate oxidizes it to pimelic acid (A. 343, 44).
lo-Aminocapric Acid, NH2[CH2]9COOH, m.p. 188°, is prepared from azelaic
monoamido-acid, NH2CO[CH2],COOH, and alkali hypobromite ; benzoyl deriva-
tive, m.p. 97°. These products are not identical with those obtained from benzoyl
dekamethylene imine (p. 365) by oxidation (C. 1906, II. 1126).
y-, S-, a-, and £- Lactams : Cyclic Amides of the 7-, S-, *-, and
£-Amino-carboxylic Acids.
These bodies are formed when the y-, 8-, and c-amino-acids are
heated to their point of fusion, when they then lose water, and undergo
an intramolecular condensation. Some of them have been obtained
by the reduction of the anil chlorides of dibasic acids — e.g. succinimide
and dichloromalein anil chloride. The names y-lactams and 8-lactams
have been given them to recall the lactones. They are cyclic acid-
amides. Just as the lactones, under the influence of the alkali
hydroxides, yield hydroxy-acid salts, So the lactams, when digested with
alkalis or acids, pass into salts of the amido-acids, from which they
can be formed on the application of heat.
Further, the y- and 8-lactams bear the same relation to the imides
of the y- and 8-alkylene diamines as the lactones to the oxides of the
y- and 8-glycols (p. 371). These relations are apparent in the following
arrangement :
CH2CH2OH CH2CH2NHa /CH2CH2OH /CH2CH2NH,
CH2<( CH/
CH2CH2OH CH2CH2NH2 N:H2CH2OH N:H2CH2NH2
Tetramethylene Tetramethylene Pentamethylene Pentamethylene
Glycol. Diamine. Glycol. Diamine.
CHaCH2V CH2CH2V /CH2CH2V /CH2C
>0 | >NH CH2< >0 CH2<
CH2CH/ CH2CH/ \:H2CH/ XCH2CH
Tetramethylene Tetramethylene Pentamethylene Pentamethylene Imine,
Oxide, Imine, Oxide. Piperidine.
Tetrahydrofur- " Tetrahydro-
furane. pyrrol.
CH-CO v CH2CO v yCHsCO v XH,CO v
NH
- v 2 v ys v
>0 | >NH CH2< >0 CH2<
CH2CH/ CH2CH/ XCH8CH/ \:H2
v-Butyrolactone. 7-Butyrolactam, l-Valerolactone. 8-Valerolactam,
o-Pyrrolidone. a-Piperidone.
CH,CO y
y-Lactams : y-Butyrolactam, a-Pyrrolidonet \ yNH, m.p. 25°, b.p. 245°,
CH 2CH 2
unites with water to form a crystalline hydrate, C4H7ON+H2O, m.p. 35°. It is
best prepared from succinimide by electrolytic reduction (B. 33, 2224). Isopropyl
pyrrolidone, C4H6ON.C3H7, b.p. 222°, is similarly prepared from isopropyl-
succinimide, and n-Phenyl Butyrolactam, C4H6ON.C6H6, from succinanil. It
can ,also be produced by reduction of dichloromalein anil dichloride (A. 295,
396 ORGANIC CHEMISTRY
27). Pyrrolidone possesses feebly basic and acid properties. Its sodium salt
reacts with iodomethane, producing n-methyl pyrrolidone, C4H6O.NCH3, an oil.
When boiled with P2S6 in xylol, pyrrolidone is converted into Thiopyrrolidone,
C4H.SN, the potassium salt of which, with iodomethane, gives Thiopyrrolidone
^-Methyl Ether, b.p. 170° (B. 40, 2831, 2848) :
CH,— NH CH2— NH \ CHt NV
\co > | \cs > | VSCH,.
I2— CH/ CH2— CH/ CHa— CH/
Pyrrolidone. Thiopyrrolidone. ^-Methyl Ether.
The ^-methyl ether, on reduction, breaks up into methyl mercaptan and
pyrrolidine (p. 335)- CH,-CH(CH,)X
v-Valerolactam, S-Methyl Pyrrolidone, \ ">NH, m.p. 37°, can be
CHa CCK
distilled without decomposition. By reduction with sodium and amyl alcohol
it is changed into a-methyl pyrroiidine (p. 335) (B. 23, 1860, 2364, 3338 ; 23,
CH 2 — CH 2 \
708). ftp-Dimethyl Pyrrolidone, aa-Dimethyl Butyrolactam, \ ">NH, m.p.
C(CHS)2CO
66°, b.p. 237° (C. 1899, I. 874).
8-Lactams : 8-Valerolactam, a-Ketopiperidine, a-Oxopiperidine, a-Pipen-
done, cH2<S^2'p2 >NH, m.p. 39-40°, b.p. 256°, is obtained, amongst other
methods, by the isomerization of cyclopentanone oxime (A. 312, 179). a-
Methyl S-Valerolactam, fi-Methyl Piperidone, CH2<^(C^S^°>NH, m.p. 55°,
is isomeric with the /3- or y-Methyl Piperidone, m.p. 87°, obtained from jS-methyl
cyclopentanone oxime (A. 312, 186). a-Ethyl 8- Valerolactam, (3-Ethyl Piperidone,
m.p. 68°, b.p.4a 141° (B. 23,
Valerolactam, p-Propyl Piperidone, CHt<J>NH, m.p. 59°, b.p. 274°.
8-n-Octanolactam, Homoconiinic Acid Lactam, CH2<CHaC° >NH , m.p. 84°.
CH 2.CH — C-gtl^
The amino-acids are not poisonous, but their y- and 8-lactams are violent,
strychnine-like poisons, affecting the spinal cord and producing convulsions.
These bodies will be met with again among the pyrrole and pyridine derivatives,
as tetrahydropyrrole and piperidine compounds (Vol. II.).
CHa.CH2.CO v
c-Caprolactam, \ /NH, m.p. 69°, is obtained by the trans-
CHa.CH2CH2/
formation of cyclohexanone oxime (A. 312, 187) ; and from c-aminocaproic
acid (p. 394). It acts, physiologically, as a nerve poison. jS-Methyl cyclo-
hexanone oxime and also oximes of the terpene ketones menthone and tetrahydro-
carvone can be converted into two methyl c-caprolactams, m.ps. 44° and 105°
(structure, A. 346, 253) and two isomeric methyl isopropyl e-caprolactams ,
menthone isooxime, m.p. 120°, and tetrahydrocarvone isooxime, m.p. 104° (A. 312,
197. 203).
CHa.CHa.CHa.NH
£-Heptolactam, \ \ , m.p. 25°, b.p.8 156°, is prepared from
CHa.CH2.CHaCO
heptamethylene ketoxime or suberone oxime. It can be broken down into
£-aminoheptylic acid (p. 395), which on warming with nitrous acid is converted
into e£-heptylenic acid (A. 312, 205).
11. Fatty Acid Nitramines, Nitramine Acetic Acid, COaHCHa.NHNOa, m.p.
103°, is prepared by hydrolyzing its ethyl ester (m.p. 24°), which results
on treating nitrourethane acetic ester, C1H6OaC.N(NO1).CHaCOaC2H6, with
ammonia (B. 29, 1682).
12. Isonitramine Fatty Acids are obtained in the form of their sodium
salts when sodium isonitramine acetoacetic esters and sodium isonitramine
mono-alkyl acetoacetic esters, or the explosive dinitroso-compounds of the
hydrazo-fatty acids, such as hydrazoisobutyric acid (p. 416), are acted on by
UNSATURATED HYDROXY-ACIDS 397
the alkalis (B. 29, 667 ; A. 300, 64). They are converted into hydroxylamino-
fatty acids by dilute mineral acids (p. 381). Acid reducing agents change them
to amino-f atty acids, whilst alkaline reducing agents produce diazo-acids (p. 402)
and hydrazino-acids (see below).
Isonitramine Acetic Acid, CO2HCH2N<Qjj, is a syrupy liquid. Isonitra-
mine Isobutyric Acid, COaHC(CH,),.N(NO)OH, m.p. 94°. Their lead salts dissolve
with difficulty.
13 (a). Hydrazino -fatty Acids are obtained, together with the diazo-acids,
when the isonitramine-fatty acids are acted on with alkaline reducing
agents. Their carbamide derivatives are obtained in the form of nitriles when
hydrocyanic acid becomes added to the ketone semicarbazides. Hydrazino-
acetic Acid, NH2NH.CHSCOOH, m.p. 152°, with decomposition (B. 31, 164).
(See also Amidohydantoine Acid Ester and Carbamidohydrazo-acetic Ester.)
a-Hydrazinopropionic Acid, Amino-alanine, NH2NH.CH(CH,)CO2H, m.p.
1 80°, is formed from a-isonitramine propionic acid (B. 29, 670), and from
the addition product of hydrocyanic acid and acetaldehyde semicarbazone
(A. 303, 79). a-Hydrazinobutyric Acid, NH2NH.C(CH3)2CO2H, m.p. 237° with
decomposition. It is formed when steam acts on its benzal derivative. The
latter is made by acting on acetone semicarbazide, NH2CONHN=C(CH3)2, with
hydrocyanic acid, when carbamido-hydrazino-isobutyronitrile is produced. This
is then decomposed with hydrochloric acid, and benzaldehyde is added (A. 290,
15).
13 (6). Hydrazo-fatty Acids. — When a hydrazino-fatty acid is treated
with acetone and potassium cyanide, a hydrazo-nitrile acid results : thus,
from a-hydrazino-isobutyric acid we get Hydrazo-isobutyronitrilic Acid,
m.p. 100°. When hydrazine sulphate (i mol.),
acetone (2 mols.), and potassium cyanide (2 mols.) react, the product is Hydrazo-
isobutyronitrile, C.NH.NH.G^3, m.p. 92°. Hydrochloric acid con-
verts both nitriles into Hydrazo-isobutyric Acid,
m.p. 223°.
Its dinitroso-compound is decomposed by alkalis into isonitramine isobutyric
acid (see above), a-hydroxy-isobutyric acid and nitrogen (A. 300, 59).
1 4 . Azo-f atty Acids. — Bromine water oxidizes hy drazo-esters and hy drazoni triles
to the corresponding azo-bodies. Azo-isobutyronitrile, (CH^>C.N:N.C<£^3)2,
m.p. 105°, when heated alone, or, better, with hot water, passes into tetramethyl
succinic nitrile (A. 290, i).
B. UNSATURATED HYDROXY-ACIDS, HYDROXY-OLEFINE
CARBOXYLIC ACIDS
a-Hydroxy-oleflne Carboxylic Acids are obtained by the action of cold hydro-
chloric acid on the nitriles, the addition products of hydrocyanic acid and olefine-
aldehydes.
Vinyl Glycollic Acid, CH2:CHCH(OH)COOH, m.p. 33°, b.p. 129°, is prepared
from its nitrite, acrolem cyanhydrin, b.p.17 94°, or the amide, m.p. 86°, b.p.21
I55-I58°- When heated with acids it is partly converted into an a-ketone-acid
— propionyl formic acid, CH,CH2CO.COOH. This also results, together with
various condensation products, when vinyl glycollic acid is acted on by alkalis
(Rec. trav. Chim. 21, 209).
Propenyl Glycollic Acid, a-Hydroxypentenic Acid, CH8CH:CHCH(OH)COOH,
is obtained from crotonaldehyde cyanhydrin. Boiling dilute acids convert it
directly into an ay-keto-acid — laevulinic acid (B. 29, 2582) :
CH3CH:CH.CH(OH)COOH - > CHSCO.CH2CH,COOH.
a-Ethoxy-acrylic Acid, CH2:C(OC2H5).CO2H, m.p. 62°, is obtained by hydrolysis
of its ethyl ester, b.p. 180° (comp. Acetal of Pyroracemic Ester, p. 408) (B. 31, 1020).
0-Hydroxy-oleflne Carboxylic Acids are obtained by condensation of olefine
aldehydes with a-halogen-fatty esters by means of zinc (comp. mode of formation
398 ORGANIC CHEMISTRY
i2a, p. 358). When an available hydrogen atom is present in the o-position,
these acids readily lose water, as when, for instance, they are boiled with sodium
hydroxide, forming di-olefine carboxylic acids (B. 35, 3633, C. 1903, 555 ; 1906, II.
Br.CH2COaR
CH,CH:CH.CHO - ^ > CH3CH:CH.CH(OH)CH2COaR
0-Hydroxy-b.ydrosorbic Acid.
- > CH3CH:CH.CH:CHC02H.
Sorbic Acid.
fi-Hydroxy-hydrosorbic Acid is an oil, slightly soluble in water ; ethyl ester,
b.p.2 100°. a-Methyl Hydroxy-hydrosorbic Ester, b.p.16 m°. a-Ethyl fi-Hydroxy
sorbic Ester, b.p.lt m°. a-Ethyl ^-Hydroxy-hydrosorbic Ester, CH3CH:CHCH-
(OH)C(CH3)2CO2R, b.p.17 119°, is stable. a-Dimethyl fi-Vinyl Hydr acrylic Acid,
Vinyl Hydroxypivalic Acid, CH2:CH.CH(OH)C(CH3)2CO2H, b.p.23 159°; ethyl
ester, b.p.19 106°, is prepared from acrolein bromisobutyric ester and zinc. In
benzene solution, P2O6 causes the splitting off of water, and simultaneously the
addition of benzene, forming the compound C<H6.CH2CH:CHC(CH3)2CO2R.
j8-Hydroxy-acrylic Acid, CH(OH):CHCO2H, and 0-Hydroxycrotonie Acid,
CH3C(OH):CH.CO2H. Both these acids and their homologues are the starting
points for the aci-forms (p. 40) of the fi-aldo- and fi-keto-carboxylic acids, such as
formyl acetic ester and acetoacetic ester :
act-form CH(OH):CHCO2C8Hf CH3C(OH):CH.CO2C2H,
keto-iono. CHO.CH2CO2C2H6 CH3CO.CH2CO2C2H6.
Formyl Acetic Ester. Acetoacetic Ester.
In the free state formyl acetic ester exists as /J-hydroxy-acrylic ester (act-
modification), whilst acetoacetic ester is more stable in the keto-form. Since
the aci- or end-form is usually looked on as being a subsidiary form, and the
aldo- or keto-iorm, the fundamental modification, those derivatives, such as
fi-alkoxy- and /?-acy/0#y-olefine carboxylic acids, which are undoubtedly of the
enol-form, will be described with the latter.
y- and 8- Hydro xy-ole fine Carboxylic Acid are known in the form of their
lactones, of which some are obtained by distillation of the y-keto acids, and others
from jSy-dibromo- or dichloro-fatty acids with the loss of 2. molecules of halogen
acid. These A1- and A« -lactones are changed back into y-keto- or aldehyde acids
by hydrolysis.
A*-Butene Lactone, Crotolactong,CH:CH..CHzCOO, m.p. 4°, b.p.15 96°, is formed
from jSy-dichlorobutyric acid when heated alone or with potassium carbonate
(C. 1905, II. 45 ; B. 35, 9422).
y-Ethoxycrotonic Acid, C2H6OCH2CH:CHCOOH, m.p. 45°, b.p.26 148°, is
obtained from y-ethoxy-jS-hydroxybutyronitrile, the addition product of hydro-
cyanic acid to epiethylin, CaH6OCH2CH.CHaO (C. 1905, I. 1138).
&*-Angelic Lactone, CH3C=CHCHaCQO, m.p. 18°, b.p. 167°, and ^-Angelic
Lactone, CH8CH.CH.CHCOO, b.p.25 83°, are prepared from laevulinic acid and
acetyl laevulinic acid. The AMactone can be formed from the AMactone by
various methods ; the change is, however, reversible. The AMactone, in contra-
distinction to the AMactone, can be condensed with aldehydes at the o-CH2
group (A. 319, 180).
Mesitonic acid (aa-dimethyl laevulinic acid, p. 423) gives rise to a-Dimethyl
^-Angelic Lactone, m.p. 24°, b.p. 167°. The isomeric aa^-trimethyl-^-butero-
lactone is -prepared from the corresponding dibromo-acid. Iso-octenolactone,
(CH8)2CHCH2CH.CH:CH.COO, is obtained from iso-octenic acid dibromide (C.
1905, II. 457 ; A. 347, 132).
y - Methyl - and y - Ethyl - oj3 - dichloro - and - ajS - dibromo - butene Lactone
R.CH.CX:CXCOO, b.p.2Z 120°, b.p.4 110°; m.p. 69°; m.p. 51°, are prepared,
from mucochloric acid and mucobromic acid (p. 402) by means of magnesium
alkyl halides (B. 38,3981).
NITRO- AND AMINO-OLEFINE CARBOXYLIC ACIDS 399
Parasorbie Acid, or Sorbin Oil, CH8CHaCHCH:CHCOO, or CH8-
CHCH2CH:CHCOO, b.p. 221°, occurs, together with malic acid, in the juice of
ripe and unripe mountain ash berries (Sorbus aucuparia). It is optically active :
[o]j = +40-8, and is a strong emetic. It passes into sorbic acid (p. 305) when
heated with sodium hydroxide or hydrochloric acid (B. 27, 344).
Di-olefine 8-lactones have been obtained from cownalic acid and isodehy-
dr acetic acid by the splitting-off of carbon dioxide :
Coumalin, CH=CH— CH=CH.COO, m.p. 5°, b.p.80 120°, has an odour like
that of coumarin (A. 264, 293).
Mesitene Lactone, ^-Dimethyl Coumalin, CH8C=CH— C(CH8)=CH.COO,
m.p. 51-5°, b.p. 245°. When heated with ammonia it changes to the corre-
sponding lactam, so-called pseudo-lutidostyril, mesitene lactam (below).
Diallyl Butyrolactone, (CH2:CHCHa)CCH2CH2COO, b.p. 267°, is prepared
from succinic ester, allyl iodide, and zinc (comp. the general method of formation
of tert.-a-hydroxy-acid esters from oxalic ester, alkyl halides, and zinc, p. 358)
(J. pr. Ch. [2] 71, 249).
Ricinokic Acid, C18H84O8, is an unsaturated hydroxy-carboxyhc acid (p. 302).
NITRO- AND AMINO-OLEFINE CARBOXYLIC ACIDS
a-Nitro-dimethyl Acrylic Acid, (CH3)2C:C(NO2)COOH. Its ester, b.p.?4 121°,
is prepared by nitrating dimethyl acrylic ester (p. 299) with fuming nitric acid.
Alcoholic potassium hydroxide converts it into the potassium salt of an isomeric
nitro-acid ester, j :^3>C.CH(NO2)COOCaH6 ; ammonia decomposes it into
acetone and nitro-acetic ester (p. 380) ; reduction with aluminium amalgam
produces nitrodimethyl acrylic ester.
a-Aminodimethyl Acrylic Acid Ester, (CH3)2C:C(NHa)C9OC,H6, b.p.lg 94°,
is converted by hydrochloric acid into dimethyl pyroracemic acid (p. 408).
j8-Amino-acids and jS-Hydrazino Oleflne Carboxylie Acids.
This group contains the reaction-products of ammonia and the hydrazines on
j8-ketone-acid esters such as acetoacetic esters and alkyl acetoacetic esters. Thus,
8-Aminocrotonic Ester, CHSC(NH2):CH.CO2CZH6, is produced; also, Methyl
NH— NH
Pyrazolone, \ . This behaves desmotropically, and because of its
CH3C:CH.CO
close connection to the j3-ketone-acid esters will be considered with them (p. 418).
8-Diolefine Lactams.
XH— COv
a-Pyridone, $~Aminopentadiene Acid Lactam, CHr; >NH, m.p. 106°,
N:H=CH/
is obtained from the reaction-product of ammonia and coumalic acid after the
elimination of carbon dioxide (B. 18, 317). It can be converted into the
C—CO\
>N.C2H6> b.p. 258°, and a-Ethoxypyridine,
=CH/
XH— C(O.C2H6U
CHr^ 7N, b.p. 1 56°, which possesses an odour like that of pyridine
\CH==CH/
(B. 24, 3144) (see Vol. II.).
Pseudohttidostyril, [3, 5]- Dimethyl a-Pyridone, Mesitene Lactam,
XH C(X
CH3— Of >NH,
XCH=C(CH8K
m.p. 1 80°, b.p. 305' is formed when ammonia acts on mesitene lactone, and
from the two monocarboxylic acids of this lactam by the elimination of CO§
(A. 259, 168).
400 ORGANIC CHEMISTRY
8. ALDEHYDE-ACIDS
These are bodies which show both the properties of a carboxylic
acid and of an aldehyde. Formic acid is the simplest representative
of the class, and it is also the first member of the homologous series of
saturated aliphatic monocarboxylic acids. But it and its derivatives
have been, with repeated reference to its aldehydic nature, discussed
before acetic acid and their higher homologues. The best known alde-
hyde carboxylic acid, a compound of the aldehyde group CHO with
the carboxyl group COOH, is glyoxylic acid, which is an oxidation
product of ethylene glycol.
I. Glyoxylic Acid, Glyoxalic Acid [Ethanal Acid] (HO)2.CH.C02H
or OCH.CO2H-f-H2O, was found by Debus (1856) among the products
resulting from the oxidation of alcohol with nitric acid. It occurs
in unripe gooseberries and other fruit, from which it disappears
on the fruit ripening. Its formation and reactions are of significance
in plant physiology (B. 25, 800 ; 35, 2446 ; 40, 4943). Just as chloral
hydrate is to be considered as trichlorethidene glycol, CC13CH(OH)2,
so crystallized glyoxylic acid can be regarded as the glycol corresponding
with the aldehydo-acid, CHO.C02H. All the salts are derived from the
dihydroxyl formula of glyoxylic acid ; hence it may be designated
dihydroxy-acetic acid. Like chloral hydrate, glyoxylic acid in many
reactions behaves like a true aldehyde (B. 25, 3425).
Methods of Formation. — Glyoxalic acid results (i) from the oxida-
tion of alcohol (B. 27, R. 312), aldehyde and glycol, and is accompanied
by glyoxal (p. 346) and glycollic acid (p. 362) ; (za) by heating dichlor-
and dibromacetic acid to 230° with water (B. 25, 714) ; (zb) by boiling
silver dichloracetate with water (B. 14, 578) ; (zc) the best method is
by the action of potassium acetate on dichloracetic acid, producing
diacetyl dihydroxy acetic acid (CH3COO)2CHCOOH, which on boiling
with water yields glyoxylic acid (A. 311, 129).
(3) From hydrazi-acetic acid (p. 405).
(4) It is formed direct by reduction of oxalic acid and its ester
(comp. also Glycollic acid, p. 362).
(a) Electrolytic reduction of oxalic acid in sulphuric acid and with mercury
cathode gives an 87 per cent, yield of glyoxylic acid (B. 37, 3187):
COOH.COOH+Ha=COOH.CH(OH)2.
(6) A similar reduction of oxalic ester produces glyoxylic ester (B. 37, 3591).
(c) Reduction of oxalic ether with sodium amalgam in alcohol produces the
alcoholate of glyoxylic ester, together with ketomalonic ester, desoxalic ester,
and racemic ester (B. 40, 4942).
Properties. — It is a thick liquid, readily soluble in water, and
crystallizes in rhombic prisms by long standing over sulphuric acid.
The crystals have the formula C2H4O4 (see above). It distils undecom-
posed with steam.
Salts. — The salts contain water of crystallization which, on being dried, give
it up with partial decomposition. The calcium salt, (C^H^OjJjCa+aHjjO, is
sparingly soluble in water (A. 317, 147 ; C. 1904, II. 1705).
Esters: Glyoxylic Ethyl Ester, CHO.COOC2H6, b.p. 130°, an easily poly-
merized substance, is produced by the electrolytic reduction of oxalic ether, and
ALDEHYDE-ACIDS 401
also from its alcoholate, C2H6OCH(OH)CO2C2H6, b.p. 137°, by the action of
PaO5. This substance is prepared by the reduction of the oxalic ether with sodium
amalgam (see above). Alcohol and hydrochloric acid produce Di-ethoxyacetic
Ester, (C2HsO)2CHCp,C2H5, b.p. 199°, which, on hydrolysis, yields di-ethoxy-
acetic acid. Glyoxylic ethyl ester develops a bright coloration with ammonia and
methylamine in presence of air (C. 1906, I. 1654 ; B. 40, 4953). Glyoxylic Methyl
Ester, m.p. 53° (B. 37, 3591). Hydrazines, hydroxylamine, etc., give typical
aldehyde derivatives with the esters (C. 1907, I. 401).
Reactions. — Glyoxylic acid exhibits all the properties of an aldehyde. It re-
duces ammoniacal silver solutions with formation of a mirror, and combines with
primary alkali sulphites (p. 195), with phenylhydrazine (B. 17, 577), with hydro-
xylamine, thiophenol and hydrochloric acid (B. 25, 3426). When oxidized (silver
oxide), it yields oxalic acid ; by reduction it forms glycollic acid and racemic
acid, CO2HCH(OH).CH(OH)COOH. On boiling the acid with alkalis, glycollic
and oxalic acids are produced (B. 13, 1931).
This reaction is extramolecular, and completes itself by the intramolecular
rearrangement of the glyoxal, under like conditions, into glycollic acid :
COOH COOH COOH
2\ +H.O =| +|
CHO CH2OH COOH.
Glyoxylic Glycollic Oxalic
Acid. Acid. Acid.
The formation of glycollic and tartaric acids also occurs when glyoxylic acid
is carefully heated (C. 1904, II. 1705) ; they are also formed by the interaction of
glyoxylic, hydrocyanic, and hydrochloric acids. Ammonia causes the elimination
of COa and the formation of formyl glycocoll (p. 388), and ultimately glycocoll
(B. 35, 2438). For the change of glyoxylic acid by urea into allantoin
(see p. 573).
II. j8-Aldo-carboxylic Acids, HOC.CHR.CO2H, and their esters
exhibit reactions of act-form compounds and behave as fi-hydroxy-&-
olefine carboxylic acids, HOCH : CRCO2H (pp. 397, 398), in which form
they are most favourably constituted to yield esters.
Formyl Acetic Acid, fi-Aldopropionic Acid (half aldehyde of malonic acid),
CHO.CH2COOH or CH(OH) : CHCO2H, appears to be formed by the hydrolysis
of its acetal, Di-ethoxypropionic acid, (C2H6O)2CHCH2COOH. This is obtained
by oxidation of j3-hydroxypropionacetal (p. 338) (B. 33, 2760) ; ethyl ester, b.p.
193° ; and also from orthoformic ester (p. 246), bromacetic ester and zinc
(J. pr. Ch. [2] 73, 326) :
HC(OC2H5),-f-BrZnCH3COOC2H6=HC(OC2H5)2.CH2C02C2H5+C2H6OZnBr.
It readily loses alcohol, forming the ester of p-Ethoxyacrylic Acid, C2H5OCH :-
CHCOOH, m.p. 110°. This readily decomposes into CO2 and acetaldehyde,
probably with the intermediate formation of formyl acetic acid.
Formyl Acetic Ester, Hydroxymethylene Acetic Ester, fi-Hydroxy acrylic Ester,
(C2H3O)CO2R, is obtained in the form of its sodium compound, NaOCH : CHCO2R,
by the condensation of formic and acetic esters by means of sodium in benzene
or ethereal solution :
HCOOC2H6+CHsCOOC2H6+Na=NaOCH:CHCOOC2H6+HOC2H5.
The free ester is easily condensed to formyl glutaconic ester, HC(OH) : C(CO2R)-
CH : CH.CO8R, and trimesic ester, C6H3(CO2R)3. Concentrated sulphuric acid
produces coumalic acid (q.v.). Acetyl chloride and sodium formyl acetic ester
form an acetate, CH3CO.OCH : CHCO2C2H6, b.p.4« 126°. This takes up 2
atoms of bromine producing a dibromide, b.p.34 154°, which indicates the structure
of the acetate (B. 25, 1046). Nitrobenzoyl chloride produces two stereoisomeric
nitrobenzoates (A. 316, 18). Cyanacetaldehyde, Hydroxymethylene Acetonitrile,
(C2H3O)CN, is produced as a sodium salt from isoxazole and sodium ethoxide
(P- 354)-
a-Formyl Propionic Acid, OCHCH(CH3)CO2H or CH(OH) : C(CH3)CO2H ;
acetal, (C,H6O)2CH.CH(CH3)CO2H, of which the ester is prepared from ortho-
formic ester and a-bromozinc propionic acid, easily breaks down into alcohol and
fi-Ethoxymethyl Acrylic Acid, C2H6OCH : C(CH3)CO2H, m.p. 109°. This is formed
from bromo-methyl-acrylic acid and sodium alcoholate. It readily decomposes
VOL. I. 2 D
402 ORGANIC CHEMISTRY
into CO, propionaldehyde and alcohol (B. 39, 3549). a-Formyl Propionic Ester.
a-Hydro^mZylenePrJpionic Ester, HOCH : C(CH3)CO,CaH,, b.p. i6i«; acetate,
b.p.4, 132° (A. 316, 333)-
III. y- and 8-Aldo-carboxylic Acids.
B-Formyl Propionic Acid, y-Aldobutyric Acid (half aldehyde of succinu -acid),
CHO CH, CH.CO.H, is produced from acetal malomc acid (C2HBO)aCH.CHaCl:
(C08H)2, when the latter is heated with water to 190° ; or, better, by boiling
Iconic acid (q.v.) in water, when COa is given off (B. 37, 1801). It forms crystals,
soluble in water. When evaporated with sodium hydroxide solution, it yields
a small quantity of terephtbalic acid (Vol. II.) ; reduction converts it into butyro-
lactone. Its nitrite serves for the derivation of fl-cyanopropionacetal, CNCH2-
CH,CH(OC.HK)t, b.p.4i 106°, the reaction product of y-chloropropionacetal
and KNC (B. 34, 1924). p-Formyl Isobutyric Acid, a-M ethyl p-Aldobutyric Acid,
CHO.CHaCH(CH8)C02H (C. 1899, I. 557)-
8-Aldovaleric Acid, y -Formyl Butyric Acid (half aldehyde of glutaric acid),
CHO CHaCHaCHaCOOH, b.p. 240°, is prepared from jS-propionacetal malonic
ester by hydrolysis and the loss of COa (B. 38, 2884) ; by boiling the ozonide of
cyclopentene (Vol. II.) with water, associated with Glutaric Dialdehyde, b.p.10 71
(p. 347) and glutaric acid (B. 41, 1706). 8-Formyl y-Methyl Valeric Acid, HOC.-
CH(CH3)CH2CH2COOH, b.p.ia 154°, is obtained by the oxidation of citronellal
acetal (p. 215) with permanganate (B. 34, 1498).
IV. Aldo-oleflne Carboxylic Acids.
B-Formyl Acrylic Acid (half aldehyde oj maletc acid), CHOCH : CHCOOH,
m.p. 55°, b.p.10 145°, is produced by the oxidation of pyromucic acid (Vol. II.)
by bromine and alkali. It is converted into succinic acid when heated with a
solution of potassium cyanide (B. 38, 1272) :
I 1 O H.o
OCH:CH.CH:CCO,H > CHO.CH:CHCO3H > HO2C.CH8.CHSCOOH.
Pyromucic Acid. /3-Formyl Acrylic Acid. Succinic Acid.
By the energetic action of chlorine and bromine on pyromucic acid, halogen
derivatives of formyl acrylic acid are produced — mucochloric acid, m.p. 125°, and
mucobromic acid, m.p. 122°.
Similarly to the y-Keto-acids (p. 421), these acids can be looked on as being
hydroxylactones, with which they are desmotropic (M. 25, 492) :
<H.CH(OH) XH.CHO XBr.CH(OH) XBr.CHO
| andCH/ CBrT / and CBrf
_ oo XCOOH ^ ^ N:oo N:OOH _
Formyl Acrylic Acid. Mucobromic Acid.
The esters of mucochloric and mucobromic acids, which, contrary to the acid,
do not yield oximes, appear to be derived from the lactone formula ; there are,
however, also esters which have been obtained from the normal aldehyde-acid.
NITROGEN DERIVATIVES OF THE ALDEHYDE-ACIDS
Dinitro-acetic Ester, (NOa)aCHCOaCaH,, is prepared from malonic ester and
fuming nitric acid. It is a colourless liquid, which cannot be distilled without
decomposition. It reacts strongly acid.
Diaminoacetic Acid, (NHa)2CHCOOH, is as yet unknown. A derivative
Tetramethyl Diaminoacetic Methyl Ester, [(CH8)2N]aCHCOOCHs, b.p.lf 57°, is
obtained from diiodoacetic ester and dimethylamine. Dibromacetic ester, by
the same reaction, yields Hydroxy-dimethyl Aminoacetic Dimtthyl Amide,
(CH,)aNCH(OH)CON(CH,)a, b.p.12 80° (B. 35, 1378)
Diazoacetic Acid, N2CH.CO2H, is also a derivative of glyoxylic
acid. As it contains two doubly-linked nitrogen atoms, it may be
compared with the aromatic diazo-bodies (see Diazobenzene). How-
ever, in the latter the extra affinities of the diazo-group — N=N— or
«=N=N are combined to two atoms, whilst in diazoacetic acid they are
N\
joined to a single carbon atom, nCH.CO^. Separated by acids
NITROGEN DERIVATIVES OF THE ALDEHYDE-ACIDS 403
from its salts, it undergoes an immediate decomposition, but it is
fairly stable in its esters and its amides.
(i) The esters of the diazo-acids result when potassium nitrite acts
on the hydrochlorides of the amino-fatty acid esters (p. 384) (Curtius,
1883, B. 29, 759) :
HCl.(H2N)CH2COaCaH5+KNOa=N2:CHC02C2H8 + KCl+2H20.
Glycocoll Ester Diazoacetic Ester.
Hydrochloride.
The di- and poly-peptide ester hydrochlorides, which contain the NH,CH2CO-
group, behave with alkali nitrites in the same way as glycocoll ester hydrochloride :
highly crystalline diazo-esters are formed, such as Diazoacetyl Glycine Ester,
N2CH.CONHCO2C2H6, m.p. 187°, as yellow crystals : Diazoacetyl Glycyl Glycine
Ester, NH2CHCO.NHCH2CONHCH2CO2CaH5, etc. The homologous ' a-amino-
acids, such as alanine leucine, also yield diazo-esters, if somewhat less readily ;
but j3- and y-amino-esters give hydroxy-esters instead of diazo-compounds (B.
37, 1263).
(2) The sodium salts of the diazo-acids are prepared by reduction of the iso-
nitramine fatty acids (p. 396) by means of sodium amalgam (B. 29, 667) :
HOaN2CH2C02Na+2H=2H20+N1:CH.COaNa.
The diazoacetic esters are very volatile, yellow-coloured liquids, with a peculiar
odour. They distil undecomposed with steam, or under reduced pressure. They
are slightly soluble in water, but mix readily with alcohol and ether. Like
acetoacetic ester, they are feeble acids in which the hydrogen of their CHN2-
group can be replaced by alkali metals by means of anhydrous alcoholates.
HNv
Isomerization occurs, and there are formed salts of isodiazoacetic ester \ \C.CO2R,
N'
which can be obtained as an unstable oil by careful precipitation. It can be
differentiated from the true diazoacetic ester by the fact that warm acids do not
liberate N2 from it (p. 404), but decompose it into hydrazine and oxalic acid
(p. 405) (B. 34, 2506). Aqueous alkalis gradually hydrolyze and dissolve true
diazoacetic ester, forming salts, CHOC2.CO,Me, which are decomposed by acids,
evolving nitrogen.
Sodium Diazoacetate, yellow in colour, dissolves with extreme ease in water.
The reaction of its solution is alkaline (B. 34, 2521).
Ethyl Diazoacetate, N2CHCO2C2H6> m.p. -24°, b.p. 143°, D28=i-o73, explodes
with violence when brought into contact with concentrated sulphuric acid. A blow
does not have this effect. At temperatures near its boiling point it decomposes
into nitrogen and fumaric ester. Its mercury salt, Hg(CN2.CO2.C2H6)2, m.p.
104°, with formation of froth, results when yellow mercuric oxide acts on
diazoacetic ester while being well cooled. It separates from ether in transparent,
sulphur-yellow, rhombic crystals. Concentrated ammonia converts it, like all
other esters, into an amide, diazoacetamide, N2CHCONH2, m.p. 114° with
decomposition. When diazoacetic ester is reduced it breaks down into ammonia
and glycocoll. Pseudo- and bis-diazoacetamide (see below). Diazoacetonitrile,
N2CH.COCN, m.p.14 46°, is prepared from amino-acetonitrile hydrochloride (p. 386)
and sodium nitrite (B. 31, 2489). It is an orange-yellow, very mobile liquid,
possessing a pleasant odour resembling acetonitrile, but which irritates the
mucous membrane.
The diazo-fatty acid compounds are all very reactive, by reason of the easy
•eplacement of nitrogen by two monovalent atoms or groups ; or else by the
ibility to form nitrogen ring-systems (Vol. II.) by means of addition or reaction
compounds without simultaneous loss of nitrogen.
(i) The diazo-esters are converted, by boiling water or dilute acids, into esters
"te hydroxy- fatty acids (glycol acids, p. 358) :
,fth
N2CHC02C2H6+H20=CH2(OH)C02C2H6-fNt
Ester of Glycollic Acid.
This reaction can serve for the quantitative estimation of the nitrogen in
404 ORGANIC CHEMISTRY
diazo-derivatives. (2) Alkyl glycollic esters are produced on boiling with
alcohols :
N,CHC02C2H,+C2H6OH=CH2(OC2H5)C02C2H,-fN1;
Ethyl Glycollic Ethyl Ester.
a small quantity of aldehyde is produced at the same time.
(3) Acid derivatives of the glycollic esters are obtained on heating the diazo-
compounds with organic acids :
N2CHC02C2H6+C2HSOOH=CH2(OC2H,0)C02H8+N2.
Acetic Acid. Aceto-glycollic Ester.
(4) The halogen acids act, even in the cold, on the diazo-compounds. The
products are haloid fatty acids :
N2CHCO2C2H5+HC1=CH1C1CO2C2H6+N1.
(5) The halogens produce esters of dihaloid fatty acids :
NCH2C02C2H5+I2=CHI2C02C2H6+N2.
Di-iodo-acetic Ester.
Diazoacetamide is changed, in a similar manner, to di-iodo-acetamide,
CHI2.CO.NH2. By titration with iodine it is possible to employ this reaction for
the quantitative estimation of diazo-fatty compounds (B. 18, 1285).
(6) The esters of anilino-fatty acids, CeH6NH.CH2CO2R, result from the
union of the anilines with diazo-esters.
(7) The esters of the diazo-fatty acids unite with aldehydes to form esters of
the fi-ketonic acids, e.g. benzoyl acetic ester, C6H6CO.CH2CO2C2H5, trichloraceto-
acetic ester, CC13COCH2CO2R (comp. p. 218) (B. 18, 2379 ; 40, 3000).
(8) Diazoacetic ester forms well-crystallizable addition products with un-
saturated acid esters, such as acrylic, cinnamic, fumaric esters. Pyrazoline-
carboxylic esters (Vol. II.) are thus formed, which, on heating lose nitrogen and
are converted into trimethylene dicarboxylic ester, e.g. —
C02R.CH CH2 C02RC CH, CO2R.CH— CH2
/\ +11 — > I! I > I
N=N CHC02R N.NH.CH.COjR CH.CO2R.
Diazoacetic Acrylic Pyrazoline Trimethylene
Acid. Acid. Dicarboxylic Ester. Dicarboxylic Ester.
(9) Diazoacetic ester also unites with benzene and its homologens, on being
heated with them, loses nitrogen and forms dicyclic bodies, such as benzotri-
methylene or norcaradiene carboxylic esters (Vol. II.) (B. 29, 108 ; 32, 701 ;
A. 358, i):
CH =CH— CH CH =CH— CH\
| || +N2CHC02R > | | >C
CH=CH— CH CH=CH— CHX
Benzene. Pseudophenylacetic Ester
(10) Diazoacetamide is converted into triazolone when heated with barium
hydroxide solution (Vol. II.) :
Nv N NH
|| >CH.CONH2 > || | .
N/ N— CH2— CO
Diazoacetyl glycinamide (see above) similarly yields triazolone acetamide
(B. 39, 4140).
(n) Hydrazine and diazoacetic ester or dizaoacetamide form the hydrazide
of azidoacetic acid, N3CH2CO2H, of which the ethyl ester, b.p.21 75°, is prepared
from iodoacetic ester and silver azide or chloracetic ester and sodium azide. It is
a colourless oil. Boiling alkalis decompose the acid into ammonia, nitrogen and
oxalic acid (B. 41, 344 ; C. 1908, I. 938) :
NaCH.CO2C2H6+2NH,NH2 > NH8+N3CH2CONHNH2+C2H5OH
. ICHtCOaR+NsAg ^N.CHgCO^
NITROGEN DERIVATIVES OF THE ALDEHYDE-ACIDS 405
(12) Diazoacetic ester has been made to yield diamide or hydrazine,
NH2NH2 by different sets of reactions (Curtius), and from these
hydr azoic acid, N3H, has been obtained (see Inorg. Chem.) :
(a) Moderate reduction of diazoacetic esters leads to the formation of salts of
hydraziacetic acid — in which form only it is stable — decomposable by acids into
glyoxylic acid and hydrazine (B. 27, 295) :
, a X 2 ,
H >CHCO2R - > | >CHCO2H - > \ -fOCH.COtH.
N/ HN' NH2
Energetic reduction decomposes diazoacetic ester into ammonia and glycocoll.
Diazo-acids can be made to yield hydrazine fatty acids by reduction (B. 29,
670).
(b) Diazoacetic ester and concentrated sodium hydroxide solution form the
salt of bisdiazoacetic acid, which is a polymer of the iso-form of the acid (p. 403
isodiazoacetic acid). The basis for the assigned constitution is that, like iso-
diazoacetic acid, it does not evolve nitrogen when warmed with acids, but de-
composes into hydrazine and oxalic acid :
H2N4C2(COOH)2+4H2O=2H4N2+2HOCO.COOH.
Bis-diazo- Hydrazine. Oxalic Acid,
acetic Acid.
(c) Ammonia and diazoacetic acid yield, besides diazoacetamide (p. 404), also
bis-diazoacetamide and pseudo-diazoacetamide ; the latter decomposes when
boiled with water into nitrogen and the azine of glyoxylic amide, which can be
further broken down into hydrazine and glyoxylic amide :
N4(CHCONH2)2 > N2+N2(:CHCONH2)2 > N2H4+2OCH.CONH2.
Pseudo-diazo Acetamide. Glyoxylic Amide Azine. Hydrazine. Glyoxylic Amide.
Oxidation converts pseudo-diazoacetamide into the red tetrazine dicarboxylic
amide. The bis-diazoacetic acid and pseudo-diazoacetic acid and reaction
products of these acids are derived from dihydrotetrazine or aminotriazoles
(Vol. II.) (B. 39, 3776) :
CH2.N:N CH.NH.NH CH.NH.N CH.N— NHa
I II I II II or || >CH
N=N-CH2 N— N=CH N— NH.CH N— N
Dihydrotetrazine. Aminotriazole.
Oxime and Hydrazone derivatives of the Aldocarboxylie Acids.
Oximidoacetic Acid, Isonitrosoacetic Acid, Glyoxylic Oxime, HON : CH.COOH,
m.p. 143° with decomposition, is prepared from glyoxylic acid and hydroxyl-
amine ; from dichlor- or dibromacetic acid, hydroxylamine and potassium
hydroxide solution ; and from the hydrolysis of its ester. It forms colourless
needles. Isonitrosoacetic Ethyl Ester, m.p. 35°, b.p.ia m°, consists of deliquescent
crystals ; methyl ester, m.p. 55°, b.p.16 100° ; isobutyl ester, b.p.10 118°, can be
prepared from acetoacetic ester by decomposition with nitroxyl sulphuric acid.
Treatment with acetic anhydride converts isonitrosoacetic ester into cyano-
formic ester, NC.CO2R ; N2O4, produces isonitrosonitroacetic ester, HONC(NO2)-
CO2R, and an oily substance, probably a peroxide of dioximidosuccinic ester :
ON=CCO2R
(comp. B. 28, 1216; 37, 1530; C. 1904, II. 195; 1907, I. 401).
N=CCO2R
p-Oximidopropionic Acid, Formyl Acetic Acid Oxime, HON : CHCH2COOH,
m.p. 117° with decomposition, is prepared from coumalic acid and hydroxylamine
(comp. p. 401) (A. 264, 286 ; B. 25, 1904).
Glyoxylic Acid Phenylhydrazone, C,HBNHN : CHCO2H, m.p. 137° with de-
composition, is decomposed by nitrous acid into CO2 and phenyl azoformaldoxime,
C,H5N : NCH : NOH (J. pr. Ch. [2] 71, 366) ; ethyl ester, m.p. 131°, can be dis-
tilled under reduced pressure (C. 1907, I. 401).
Hydrazones of ^-Aldocarboxylie Acids, such as of formyl acetic acids, and their
esters very easily part, intramolecularly, with water or alcohol, forming lactam-
like bodies, known as pyrazolones (Vol. II.). In order to indicate the lactam
4o6 ORGANIC CHEMISTRY
character of such substances, when the lactam-nitrogen is joined to a second
nitrogen atom in the ring, they have been named lactazams :
CH 2OH CH— NH— NH CH =N— NH
|| +NH8— NH, M| I or I I
CH.C02R CH CO CH2 CO
Aci-Formyl ** _ • ""
Acetic Acid. Pyrazolone.
jS-Ketocarboxylic acids (p. 416) also easily form y-lactazams (pyrazolones).
Hydrazones of the y- ando-Aldocarboxylic Acids.
B-Formyl Propionic Acid Ester Phenylhydrazone is a non-cry stallizable oil;
phenylhydrazide, C,H,NHN : CHCH2CH2CONHNHC,H6, m.p. 182°, is prepared
from aconic acid (q.v.) and excess of phenylhydrazine. When warmed with
sulphuric acid it yields indole j3-acetic acid (A. 339, 373). Similarly, Formyl
Butyric Acid Phenylhydrazone, C8H5NHN : CHCH2CHaCH2COOH, yields indole
j8-propionic acid, which is also formed from tryptophane by putrefaction (B. 38,
2884).
Mucobromic acid (p. 402) and hydrazines form hydrazone anhydrides or 8-lacta-
zams (Pyridazones, Vol. II.) ; with hydroxylamine it gives an oxime anhydride
(lactaxone or orthoxazone, Vol. II.) (B. 32, 534) :
CBr— CH =N CBr— CH =N
CBr— CO— NH CBr— CO— O
Dibromopyridazone, Dibromo-orthoxazone
m.p. 224°. m.p. 125°.
9. KETONIC CARBOXYLIC ACIDS
These contain both the groups CO and CO2H ; they, therefore,
show acid and ketone characters with all the specific properties peculiar
to both. In conformity with the scheme of nomenclature employed
for the mono-substituted fatty acids and the various diketones (pp.
284, 348), we distinguish the groups a-, j8-, y-t S-, etc., among the
ketocarboxylic acids :
The a-, y-, and 8-, etc., acids are fairly stable in a free condition,
whilst the j8-acids can exist only in the form of esters.
Nomenclature. — The names of the ketonic acids are usually derived
from the fatty acids, inasmuch as the acid radicals are introduced into
these ; e.g. —
CH3CO.C02H CH8CO.CH2C02H CH3CO.CH2CH2CO2H
Acetyl Formic Acid. Acetyl- or Ace to-acetic Acid. /3-Acetyl Propionic Acid.
or these acids may be viewed as ^^-substitution products of the
fatty acids or oxofatty acids (p. 218) :
CH3.CO.Cp2H CH3.CO.CH2CO2H CH3.CO.CH2CH2CO2H
a-Ketopropionic Acid /3-Ketobutyric Acid y-Ketovaleric Acid
(a-Oxopropionic Acid). Q3-Oxobutyric Acid). (y-Oxovaleric Acid).
The " Geneva names " are formed by the addition of the word " acid " to the
names of the ketones, as the ketonic acids may be considered as being the oxidation
products of the latter :
CHSCOC02H CH8CO.CHaC02H CH8COCH2CH2CO2H.
[Propanone Acid]. a-Butanone Acid]. [3-Pentanone Acid].
Formation.— The more stable a-, y-, and 8-ketonic acids can be
prepared by the oxidation of the secondary alcohol acids corresponding
with them. Other methods will be given under the individual classes
of these acids.
SATURATED KETONE CARBOXYLIC ACIDS 407
Reactions. — The ketone nature of these acids exhibits itself in
numerous reactions, e.g. nascent hydrogen converts all the ketonic
acids into the corresponding alcohol acids. They unite with alkali
hydrogen sulphites, with hydroxylamine, and with phenylhydrazine.
A. SATURATED KETONE CARBOXYLIC ACIDS
I. a-Ketonic Acids.— R.CO.CO2H.
In this class the ketone group CO is in direct union with the acid-
forming carboxyl group, CO2H. We can look upon them as being
compounds of acid radicals with carboxyl, or as derivatives of formic
acid, HCO.OH, in which the hydrogen linked to carbon is replaced by
an acid radical. This view indicates, too, the general synthetic method
of formation of these acids from (i) the cyanides of acid radicals (p.
409), which, by the action of concentrated hydrochloric acid, are
changed to the corresponding ketonic acids :
CH,.CO.CN+2H,0+HC1=CH3.CO.C02H+NH4C1.
(2) A second general method of formation of a-ketonic acids and
their esters consists in converting a-alkyl acetoacetic esters into the
a-oximido-fatty acids (p. 410) and decomposing these with nitrosyl
sulphuric acid (C. 1904, II. 1706) :
HONiCRCOOC.H, - > O:CRCOOCaH,-f N,O+H2O.
Pyroracemic Acid, Pyruvic Acid, Acetyl Formic Acid, [Propanone
Acid], CH3.CO.CO2H, m.p.4-3°, b.p.760 165-170° with decomposition,
b.p.12 61°, was first obtained in the distillation of tartaric acid, racemic
acid (Berzelius, 1835) and glyceric acid, (i) The acid is made by the
distillation of tartaric acid alone (A. 172, 142) or with potassium hydro-
gen sulphate (B. 14, 321). We may assume that in this decomposition
the first product is hydroxymalei'c acid, which is converted into
oxalacetic acid, which then gives up CO2 to form pyroracemic acid :
CHOHCOaH
COH.COaH
CO.C02H
COC02H
CHOHCOjH
Tartaric Acid.
CH.C02H
Hydroxymalelc
Acid.
CH2CO2H
Oxalacetic
Acid.
CH,
Pyroracemic
Acid.
It is synthetically prepared from (2) a-dichloropropionic acid (p. 289),
when heated with water ; (3) in the oxidation of a-hydroxypropionic
acid or ordinary lactic acid with potassium permanganate ; (4) by
the decomposition of oxalacetic ester ; (5) from acetyl cyanide by
the action of hydrochloric acid (p. 409) ; (6) by the oxidation of citra-
conic and mesaconic acid by KMnO4.
Pyroracemic acid is a liquid, soluble in alcohol, water and ether,
and has an odour quite similar to that of acetic acid. On boiling at
atmospheric pressure it decomposes partially into CO2 and pyrotartaric
acid (q.v.). This change is more readily effected if the acid be heated
to 100° with hydrochloric acid.
Reactions, — The acid reduces ammoniacal silver solutions with the production
of a silver mirror, the decomposition products being COX and acetic acid. It is
4o8 ORGANIC CHEMISTRY
quantitatively decomposed into these substances by hydrogen peroxide (C. 1904,
II 194) When heated with dilute sulphuric acid to 150° it splits up into CO,
and aldehyde, CH,.COH. This ready separation of aldehyde accounts for the
ease with which pyroracemic acid enters into various condensations, e.g. the
formation of crotonic acid by the action of acetic anhydride (p. 291) (B. 18, 987.
and 19 1089) and the condensations with dimethyl aniline and phenols in the
presence of ZnCl,. The acid condenses with the benzene hydrocarbons, in the
presence of sulphuric acid, without decomposition (B. 14, 1595 '. 16, 2072). (See
also, Acetone Pyroracemic Acid.)
Pyruvic acid forms crystalline compounds with the alkali hydrogen sulphites,
in which it resembles the ketones. Nascent hydrogen (Zn and HC1, or HI)
changes it to ordinary o-lactic acid. CHSCH(OH)CO,H, and dimethyl racemic
acid (comp. Glyoxylic Acid, p. 400). H,S passed through pyroracemic acid
produces thiodilactic add, S[C(CH,)(OH)COOH],, m.p. 94°. which is easily
decomposed into its components (C. 1903, I. 16). Mercaptans, e.g. phenyl-
mercaptan, combine with pyroracemic acid to form CH,C(OH)(SC,H6)CO,H
(B. 28, 263). Pyroracemic ester, mercaptan and hydrochloric acid react together
to form the mercaptol CH,.C(SC,H6),CO,C,H5, which on oxidation passes into
CH,C(SO,C,H,),CO,C,H8, m.p. 61° (B. 32, 2804).
For the behaviour of pyroracemic acid with NH,, NH,OH, C8H6NHXH,, see
" Nitrogen derivatives of the o-ketonic acids." It combines with HNC to form
the half-nitrite of a-hydroxyiso-succinic acid.
The change of pyroracemic acid on boiling with barium hydroxide
solution into uvitic acid, CeH,[i,3,5](CH,)(CO,H), (Vol. II.) and uvic acid or
pyrotritaric acid (Vol. II.), is noteworthy. The first step is the separation of
oxalic acid with the formation of methyl dihydrotrimesic acid ; then, CO, is
given off and dihydrouvitic acid results ; finally, oxidation produces uvitic acid
(A. 305, 125). These intermediate compounds can be avoided by condensing
pyroracemic acid with acetaldehyde, a reaction which is of general application.
For the condensation of pyroracemic acid with formaldehyde, see tetramethylene
dioxalic acid (Vol. II.).
On standing, a slow aldol-like condensation takes place, which can be accele-
rated by the presence of hydrochloric acid, whereby two molecules of pyroracemic
COOH.CfCH,)— O
acid unite to form o-ketovalerolactone y-carboxylic acid,
CH,.CO.CO
(q.v.). Heated with hydrochloric acid this substance gives up COJ( and pyrotartaric
acid is formed (see also C. 1904, II. 1453). The salts of pyroracemic acid are caused
to undergo polymerization by the action of alkalis to salts of para-pyroracemic acid
and meta-pyroracemic acid (A. 317, I ; 319, 121 ; C. 1901, II. 1262 ; 1903, I. 16).
Pyroracemic Ethyl Ester, m.p. 146°; acetal, CH^OCjH^j.COjCjHs, b.p.
190° (see also o-ethoxy acrylic ester, p. 397).
Halogen Substitution Products of Pyroracemic Acid. — Trichloropyroracemic
Acid, Isotrichlorogly eerie Acid, CC1,.CO.CO,H+H,O=CC1,.C(OH),COOH, m.p.
102°, is produced (i) when KC1O, and HC1 act on gallic acid and salicylic
acid ; (2) by the action of chlorine water on chlorofumaric acid (B. 26, 656) ;
(3) from trichloracetyl cyanide.
Substitution products result by heating the acid with bromine and water to
100°. Dibromopyruvic Acid, CBr,HC(OH),CO,H+H,O, m.p. 89°, anhydrous.
Tribomopyruvic Acid, CBr,C(OH),.CO,H+H,O, m.p. 90°, anhydrous. Heated
with water or ammonia, it breaks up into bromoform, CHBrs. and oxalic acid.
Homologues of Pyroracemic Acid, Homopyroracemic Acids.
Propionyl Formic Acid, CH,CH,CO.COOH,b.p.,5 74-78°, is also obtained by
the transformation of vinyl glycollic acid (p. 397) ; ethyl ester, b.p. 162° (C. 1904,
I. 1706). Butyryl Formic Acid, CHtCH,CH,CO.CO,H, b.p.8S 115° ; ethyl ester,
b-P-it 72-770. is produced from o-oximidovaleric ester (mode of formation No. 2,
p. 407). Dimethyl Pyroracemic Acid, (CH,),CHCO.COOH, m.p. 31°, b.p.lt 66°, is
produced by the cleaving action of hydrochloric acid on dimethyl-2-amino-acrylic
acid (p.Q399) (C. 1902, I. 251). Trimethyl Pyroracemic Acid, (CH3y3.CO.COOH,
m.p. 90 , b.p. 185°, results when pinacoline is oxidized with KMnO4 (B. 23,
R.2i ; C.I898, 1.202). /so&«/y/Pyrar^mic^ct^,(CH,),CHCH,.CH,CO.COOH,
fl'PoAc ' 1S obtamed from isobutyl citraconic acid and isobutyl mesaconic acid
A. 305, 60) i ; ethyl ester, b.p.n 74°, is prepared from o-oximidoisocaproic ester
(C. 1904. II. i737; I006. II. 1824).
NITROGEN DERIVATIVES OF THE KETONE ACIDS 409
NITROGEN DERIVATIVES OF THE a-KETONIC ACIDS
(1) Carboxyl Cyanides, a-Ketone Nitriles result on heating acid chlorides or
bromides with silver cyanide :
C2H8O.Cl+AgNC=CaH8O.CN+AgCl ;
and when the aldoximes of the a-aldehyde ketones are treated with dehydrating
agents, such as acetic anhydride (p. 353) (B. 20, 2196) :
CH8.CO.CH:NOH=CH8.CO.CN+HaO.
The acid cyanides are not very stable, and, unlike the alkyl cyanides, are con-
verted by water or alkalis into their corresponding acids and hydrogen cyanide,
CH8CO.CN+HaO=CH3CO.OH+HNC.
With concentrated hydrochloric acid, on the contrary, they undergo a transposi-
tion similar to that of the alkyl cyanides (p. 280), in which water is absorbed,
and the amides of the a-ketonic acids are intermediate products (Claisen) :
H20 HaO
CH3COCN > CH3COCONHa ^-> CH3COCOOH +NH4C1.
Acetyl Cyanide, CH8CO.CN, b.p. 93°. When preserved for some time, or
by the action of KOH or sodium, it is transformed into Diacetyl Cyanide,
C6H8O2N2, m.p. 69°, b.p. 208°, which can also be prepared from acetic anhydride,
potassium cyanide and hydrochloric acid in ether at o°. Hydrolysis converts it
into methyl tartronic acid, probably according to the following scheme (M. 16,
773):—
CH3\ CH3v /OCOCH8 CH3V /OH
2 >CO > >C< > >C< -fHO.COCH,
NCX NC7 XCN HOCCK XCOOH
Diacetyl Cyanide. Methyl Tartronic Acid.
Pyruvic Nitrile, Propionyl Cyanide, CH3CH2COCN, b.p. 108-110°. Dipropionyl
Cyanide, (C8H6OCN)2, m.p. 59°, and b.p. 200-210°, behaves like diacetyl cyanide
(B. 26, R. 372). Butyryl Cyanide, C8H7COCN, b.p. 133-137°, and isobutyryl
cyanide, C3H7COCN, b.p. 118-120°, polymerize readily to dicyanides, which pass
into alkyl tartronic acids on treatment with hydrochloric acid.
Pyroracemic Amide, CH3CO.CONH2, m.p. 124°. Propionyl Formamide,
CaH6CO.CONH2, m.p. 116°, is produced from o-ketone nitriles and concentrated
hydrochloric acid (B. 13, 2121).
Pyruvyl Ethyl Imidochloride, CH8COCC1 : NC2H6, is a yellowish oil produced
by the union of chloracetyl with ethylisocyanide (A. 289, 298).
Pyruvyl Hydroximic Chloride, Chlorisonitrosoacetone, CH,COC(NOH)C1, m.p.
105°. is formed :
By the action of nitric acid on chloracetone ;
By the action of chlorine on isonitrosoacetone ;
When hydrochloric acid acts on Pyruvyl Nitrolic Acid, Acetyl Methyl Nitrolic
Acid, CH8CO.C(=NOH)ONO or CH3.CO.C(=NOH)NOa— the product resulting
from the action of nitric acid on acetone (A. 309, 241). The oxime, CH,.C:-
NOH.C(:NOH)O.NO, m.p. 97° with decomposition.
(2) Behaviour of Ammonia and Aniline with Pyroracemic Acid. — The
ammonium salt, like the other alkali salts, undergoes condensation in neutral or
alkaline solution. At first an amino-ketone dicarboxylic acid is formed, which
loses formic acid and passes into uvitonic acid, a picoline dicarboxylic acid (C. 1904,
II. 192):
CH,C(COOH)NHt COCOaH CH8C N=^C.COOH
2CH,COCOaNH4->- +1 -> || |
CH2CO(C02H) CH, CH.C(COOH):CH
Aniline and pyroracemic acid produce anil-pyruvinic acid, C9HBN : C(CH,)-
COOH, m.p. 126°, with decomposition, which undergoes a similar condensation
with a further molecule of pyroracemic acid to form a- methyl cinchonic acid,
forming anil-uvitonic acid (Vol. II.).
In acid solution one molecule of NH3 and two of pyroracemic acid unite to
form iminodilactic acid (comp. Thiodilactic Acid, p. 408), with th* probable
4Id ORGANIC CHEMISTRY
formation of intermediate compounds. On losing CO2 it forms acetyl alanine
(p. 388) (C. 1904, II. 193) : _co
CH.C(COOH)(OH)NHC(OH)(CH,)COOH ^ > CH3CONH.CH(CH3)COaH.
(*} a-Oximido-fatty Acids or oximes of the a-ketone acids are formed (a) by
the action of NHaOH on a-ketone acids ; (&) by the interaction of mono-alkyl
acetoacetic acid and nitrous acid, alkyl nitrites, nitrosyl sulphuric acid or nitrosyl
chloride (B. 11, 693 ; 15, 1527 ; C- 1904, II. 1457. ^o6) :
CH8COCH(CH8)COaR+H08SONO > CH,COISO,H+HON:C(CHt)CO1R
Further action of nitrous acid converts the a-oximido-esters into a-ketone esters
(p. 407). Acetic anhydride causes the splitting off of water and COa with
formation of acid nitriles.
a-Oximidopropionic Acid, Isonitrosopropionic Acid, (,H3C=N(OJ ,O2H,
decomposes at 177°; methyl ester, m.p. 69°, b.p.14 123°; ethyl ester, CH3C =
N(OH)COaCaH6, m.p. 94°, b.p. 238° (B. 27, R. 47°) ; amide, CH8.C : N(OH)-
CONHa, m.p. 174° (B. 28, R. 766 ; C. 1904, II. 1457)- a-Oximidobutyric Acid,
CH,.CH1C=(NOH)CO2H. a-Oximidovalerianic acid, and a number of other homo-
logues and their esters have also been prepared. a-Oximido-Dibromopyroracemic
Acid has been obtained in two modifications (B. 25, 904).
NHV
(4) Hydrazipropionic Ethyl Ester, j ^>C(CH3)CO2C2H5, m.p. 116° (J. pr. Ch.
[2] 44, 554), results from pyroracemic acid and hydrazine. Mercuric oxide
converts its methyl ester into a-diazopropionic methyl ester.
Nv
(5) a-Diazopropionic Ester, ||^C(CH3)CO2C2H6, b.p.41 65-68°, is obtained
from the hydrochloride of alanine ethyl ester by the action of KNOa. It is a
yellow oil, which is partially decomposed, by distillation at ordinary pressure, into
dimethyl fumaric ethyl ester. a-Diazobutyric Ester, b.p.u 63-65°, and a-Diazo-
isocaproic Ester, b.p.12 70-73°, both resemble diazoacetic ester (p. 403) in their
behaviour, but are more easily decomposed, and are therefore more difficult to
obtain pure (B. 87, 1261).
(6) Phenylhydrazone Pyroracemic Acid, CH3C(=NNHC6H6)CO2H, m.p. about
192° with decomposition, is not only formed by the action of phenylhydrazine
on pyroracemic acid (B. 21, 984), but also in the saponification of the reaction-
product from diazobenzene chloride and methyl acetoacetic ester (B. 20, 2942,
3398 ; 21, 15 ; A. 278, 285 ; C. 1901, II. 212).
Pyroracemic ethyl ester yields two isomers with phenylhydrazine, which are
separable by chloroform : phenylhydrazones, m.p. 32° and 119° (C. 1900, II. 1150).
(7) Semicarba zones of the a-Ketonic Acids, NHaCO.NHN:CRCOgH, and
their esters, see C. 1904, II. 1706, etc.
II. j3-Zetonic Acids.
In the j3-ketonic acids the ketone oxygen atom is attached to the
second carbon atom, counting from the carboxyl group forward.
These compounds are very unstable either in the free state or as salts.
Heat decomposes them into carbon dioxide and ketones. The CO
and CO2H groups are attached to the same carbon atom, and, in this
respect, direct attention to malonic acid and its mono- and di- sub-
stitution products (see later), in which two carboxylic groups are
attached to the same carbon atom ; they also give off CO2 when heated.
Their esters, on the other hand, are very stable, can be distilled without
decomposition, and serve for various and innumerable syntheses.
Acetoacetic Acid, Acetyl Acetic Acid, Acetone Monocarboxylic Acid,
p-Ketobutyric Acid fc-Butanone Acid], CH3.CO.CH2.CO2H. To
obtain the acid, the esters are hydrolyzed in the cold by dilute potas-
sium hydroxide solution (the rate of hydrolysis is independent of the
PARAFFIN KETONE CARBOXYLIC ACIDS 411
concentration : B. 32, 3390 ; 33, 1140) ; the acid is liberated with
sulphuric acid, and the solution shaken with ether (B. 15, 1781 ; 16,
830). Concentrated over sulphuric acid, acetoacetic acid is a thick
liquid, strongly acid, and miscible with water. When heated, it yields
carbon dioxide and acetone :
CHSCO.CH2C02H=CH8CO.CH3+CO,.
Nitrous acid converts it at once into CO2 and isonitroso-acetone (p. 354). Its
salts are not very stable ; it is difficult to obtain them pure, since they undergo
changes similar to those of the acid. Ferric chloride imparts to them, and also
to the esters, a violet-red coloration. Occasionally the sodium or calcium salt
is found in urine (B. 16, 2134 ; C. 1900, II. 345).
The homologous fl-Ketone acids can also be prepared by the hydrolysis of
their esters with hot concentrated sulphuric acid : the resulting liquid may
contain the sulphates of the aci- and enol forms : RC(OSO3H)CHCO2H. The
free acids, like acetoacetic acid itself, easily decompose into CO2 and ketones
(C. 1904, II. 1707).
The stable acetoacetic esters, CH3CO.CH2C02R, are produced
by the action of metallic sodium on acetic esters. In this reaction
the sodium compounds constitute the first product :
2CH3COOC2H5+Naa > CH3CONaCHCOOC2H6+C,H4ONa-f Ha.
Acetic Ester. Sodium Acetoacetic Ester.
The free esters result upon treating their sodium compounds with
acids, e.g. acetic acid,
CH,CONaCHC02C2H5+CH3C02H > CH,COCHaCOOC2H,+CHtCO2Na
and are obtained pure by distillation.
The acetoacetic esters are liquids, which dissolve with difficulty
in water, and possess an ethereal odour. They can be distilled without
decomposition.
The esters of acetoacetic acid, contrary to expectation, possess an
acid-like character. They dissolve in alkalis, forming salt-like com-
pounds in which a hydrogen atom is replaced by metals.
Historical. — In 1863 Geuther investigated the action of sodium on acetic ester.
Simultaneously and quite independently of Geuther, Frankland and Duppa, in con-
cluding their studies upon the action of zinc and alkyl iodides on oxalic ether
(p. 358), investigated the action of sodium and alkyl iodides on acetic ester.
JT. Wisliccnus has contributed very materially to the explanation of the reactions
here involved (1877), A. 186, 161.
Constitution. — The /3-ketone acids belong to the same class of substances
which includes the J3-ketone aldehydes, /3-diketones (p. 348), and jS-aldo-
carboxylic acids (p. 401), namely those which occur in desmotropic or pseudo-
meric form (comp. p. 38) ; e.g. acetoacetic ester :
CHSCO.CH2C09H •< > CH3C(OH):CHC09H
0-Ketobutyric Acid. /3-Hydroxycrotonic Acid.
CH8CO.CH2COOC2H6 -< > CH3C(OH):CH.COOC2H,
Acetoacetic Ester. Aci- Acetoacetic Ester.
Evidence for the Ketonie character of free Acetoacetic Ester.
The esters of jS-aldocarboxylic acids, such as formyl acetic ester, show their
constitution to be of the aci-form, and that therefore they must be considered as
being hydroxymethylcne compounds ; the free acetoacetic ester, however, is
best expressed by the formula, CH3COCH2COOCaH$. This substance, with
4I2 ORGANIC CHEMISTRY
orthoformic ester, gives an acetal, £-diethoxybutyric ester— CH3C(OC,H,),-
CH, COOC.Hr, thus behaving like the simple ketones (p. 225).
The physical properties of the ester, its refraction (B. 31, 1964), molecular
rotation and behaviour towards electric waves, all point to a ketonic con-
stitution.
Sodium acetoacetic ester was formerly also considered to possess the same
structure and received the formula CH3CO— CHNaCOOC2H6, because its reaction
with alkyl and acyl halides always yielded a C-derivative, CH3COCHR.COOC2H5.
The first example of a different course of reaction was found in the formation of
an O-derivative, j3-carboxethyl hydroxycrotonic ester, CH3C(OCO2C2H8) :-
CHCO2C2H5, from sodium acetoacetic ester and chlorocarbonic ester (Michael,
J. pr. Ch. [2] 37, 473 ; Claisen, B. 25, 1760, A. 277, 64). It has, however,
already been pointed out (p. 40) that substances which occur in the forms
(!) — CO.CH2,CO — , and (2) — C.CH : C(OH) — , only form salts directly accord-
ing to the second formula. This occurs by the action of alkalis on the first
substance, and acetoacetic ester can be taken as an example of this :
CH8COCH2COOC2H5+NaOH=CH3C(ONa) : CH.COOC2H5-f H2O.
These views on the varying structure of acetoacetic ester are confirmed by
investigations on the refraction of the two forms (Bruhl and Schroder, B. 38, 220,
1870).
In the majority of cases of reaction between sodium acetoacetic ester with
alkyl and acyl halides, the invading group enters another position than of the
metallic atom. For the explanation of such " abnormal " reactions see Michael,
J. pr. Ch. [2] 37, 473, etc. (also p. 413).
As the jS-ketonic acids are so very unstable, their more stable esters
are employed in their study. These can be made according to the
following reactions :
Formation of Acetoacetic Ester and its Homologues.
(i) By the action of sodium or sodium alcoholate on acetic ester.
These reagents act similarly on propionic ester, with the formation
of a-propionyl propionic ester, CH3CH2CO.CH(CH3)CO2C2H5.
However, when sodium acts on normal butyric ester, isobutyric ester and
isovaleric ester, it is not the analogous bodies which result, but hydroxy-alkyl
derivatives of higher fatty acids (A. 249, 54).
The reaction between sodium and acetic ester only takes place in
the presence of a trace of alcohol, with which the sodium can combine
to form the alcoholate (B. 3, 305). It must be assumed, therefore,
that the condensation is brought about by the action of sodium ethoxide,
which causes the splitting off of alcohol :
2CH3COOCaH6+NaOC,H5=CH8C(ONa):CHCOOC2HB-f2CjH5OH;
which unites with excess of sodium to form a further quantity of
alcoholate. The synthesis can actuaUy be carried out when separately
prepared sodium ethoxide is employed instead of metallic sodium,
the yield being only slightly inferior (Claisen, private communication),
bodmm amide can also be employed (B. 35, 2321 ; 38, 694).
If, however, sodium be made to act on the ester in ether or benzene
solution, there results the sodium salt of an acyloin (p. 341). On the
directive influence on the course of reaction exerted by the nature of
the solvent, see C. 1907, II. 30.
PARAFFIN KETONE CARBOXYLIC ACIDS 413
The first step in the synthesis can be taken as being the formation
of a compound :
or
(the latter perhaps resulting from the former by the loss of alcohol).
The ortho-derivative then reacts with the still unchanged ester :
,N. x,5 v jv
>C< + >CH.COOC,H6 = >C:CH.COOC2HS+2C2H5OH;
NaO/ \DC2H5 H/ NaO/
or else, a molecule of the ester and a molecule of the sodium ester
unite and then split off alcohol :
<C2H5 CH2^ r /OCIHiCH«K i
+NaO-COC2H5 - >• CH3C^ -- O - COC2H6 - >
L \ONa J
/OC2H5 -C2H6OH
CH3Cf - CH2— COC2H5 - > CH3C = CH— COC2H5
"-ONa O^
(Comp. Claisen and Michael, A. 297,92; B. 36, 3678; 38, 714, 1934.) Both
assumptions coincide equally well with the fact that fatty acid esters do not
condense, analogously to the above, with secondary and tertiary alkyl groups.
(2) The interaction between the sodium compound of acetoacetic
ester, and of mono-ethyl acetoacetic ester, with alkyl halides, especially
the iodide and bromide, results in the formation of homologous esters.
An examination of the structural formula for the acetoacetic ester
reveals that only one hydrogen is replaceable by sodium. The metallic
compound reacts with the halogen alkyl, whereby the sodium salt is
formed and the alkyl group becomes attached to the a-C atom.
(a) C2H8OCO— CH CH8 C2H6OCO.CH.CH,
|| + | - I +NaI.
CH3— CONa I CH3— CO
Sodium Acetoacetic Ester. a-Methyl Acetoacetic Ester. .
The mono-alkyl substituted ester can take up an atom of sodium and
again react as above :
(6) C,H6OCO— CCH, CaH5 CaH6OCO— C(CH8)C,H6
II +1 I +NaI.
CH3— CONa I CH3-CO
.-Methyl Sodium Acetoacetic Methyl Ethyl Acetoacetic
Ester. Ester.
The a-dialkyl acetoacetic esters do not take up a further quantity
of sodium.
Preparation of Acetoacetic Ester and the Alkyl Acetoacetic Esters. — Sixty parts
of metallic sodium are gradually dissolved in 2000 parts of pure ethyl acetic ester,
and the excess of the latter is distilled off. On cooling, the mass solidifies to a
mixture of sodium acetoacetic ester and sodium ethoxide. The remaining
liquid is mixed with acetic acid (50 per cent.) in slight excess. The oil separated
and floating on the surface of the water is siphoned off, dehydrated with calcium
chloride, and fractionated (A. 186, 214, and 213, 137). For the preparation of
the dry sodium compound, see A. 201, 143.
For the preparation of the alkyl acetoacetic esters according to the second
method, it is not necessary to prepare pure sodium compounds. To the aceto-
acetic ester dissolved in 10 times its volume of absolute alcohol, is added an
equivalent amount of sodium and then the alkyl iodide, after which heat is
414
ORGANIC CHEMISTRY
applied. To introduce a second alkyl an equivalent quantity of the sodium
alcoholate and the alkyl iodide are again employed (A. 186, 220 ; 192, 153 ; C.
1904, II. 309). In some cases sodium
hydroxide may be substituted for sodium
ethoxide in these syntheses (A. 250, 123 ;
comp. B. 33, 2679).
Or, sodium may be allowed to act on the
sodium acetoacetic ester dissolved in some
indifferent solvent, e.g. ether, benzene,
toluene, xylene. To get the sodium in a
finely divided form, so that it may act with
a perfectly untarnished surface, it is forced
through a sodium press (Fig. 1 1 ) into the diluent
or solvent. In order that a known quantity
of sodium wire shall be employed, a finely-
divided and adjustable brass scale is attached
to the frame of the press, whilst the plunger
carries a pointer. After the quantity of
sodium expressed corresponding with the di-
vision on the scale, has once and for all been
determined, the amount of metal employed
can always be controlled. (H. Meerwein and
G. Schroeter, private communication ; also
Kossel, C. 1902, II. 718.) The choice of the
indifferent solvent depends on the greater or
less difficulty with which the halogen atom
is displaced. In many such reactions it is
necessary to heat the substances together for
days at the boiling point of the solvent
(comp. A. 259, 181).
(3) The C-acyl acetoacetic ester can be employed in the formation of homo-
logous acyl esters ; it is carefully heated with alkali, whereby an acetyl group is
split off (C. 1902, II. 1410) :
NaOH
CH3CH2CH2COCH(COCH3)COOR > CH3CHaCHaCOCH2CO2R.
C-Butyl Acetoacetic Ester. Butyl Acetic Ester.
The action of iodo-alkyl and sodium acoholate on the C-acyl acetoacetic ester
is to split off the acetyl group as acetic ester and replace it by alkyl (C. 1904,
II. 25).
(4) A further general method for the synthesis of jS-ketone-acid esters consists
in the action of magnesium on a-bromo-fatty acid esters in ethereal solution
(B. 41, 589, 354) :
FIG. IT.
x
-C(OC,H6)<
OMgBr
\;(CH3)2C02C8H.
OC(CH3)2C02C2H
Isobutyl Isobutyric Ester.
+MgBra+MgO=C2H3OH.
(5) A further synthesis depends on the action of metallo-orgamc compounds
on nitriles :
(a) Acid nitriles are condensed with a-bromo-fatty esters by zinc, and the
product is decomposed with water (C. 1901, I. 724) :
NZnBr
Butyronitrile.
(CH3)aC02R
HaO
C,H7C
\:(CH8)2C02R.
Butyl Isobutyric Ester<
REACTIONS OF THE j8-KETONIC ESTERS 415
(b) The condensation of cyanacetic ester with magnesium alkyl iodides
and subsequent action of water also produces j8-ketone-acid esters (C. 1901.
I. 1195):
IMgCsH5 HaO
Cyanacetic Ester.
N|CCH2C08R -^C2H5C(: NMgI)CH2CO2R — X:2H6COCH2CO2R.
Propionyl Acetic Ester.
(6) The higher esters can also be prepared by the action of ferric chloride on
acid chlorides, whereby a ketonic acid chloride is first formed. Water causes the
loss of COa, forming a ketone (p. 218), but the action of alcohol is to produce the
ketonic acid ester (Hamonet, B. 22, R. 766) :
-HCl /CH3 CaH6OH ,CH8
2C2H6COC1 - > C2H8COCH< - > C2H6COCH<
XCOC1 XCOOC2H6
Propionyl Chloride. a- Propionyl Propionic Ester.
The higher chlorides, such as butyryl and cenanthylic, can be employed in
this reaction.
(7) When a-acetylene carboxylic acids are boiled with alcoholic potassium
hydroxide, water is taken up and jS-acyl acetic acids result. By esterification
with alcohol and mineral acids at o°, the j8 -ketonic acid esters are formed (C. 1903,
I. 1018) :
H20
C,H13CEE£.C02H - - > C6H18CO.CHaC02H - > C6H]3CO.CH2COOCaH5
Hexyl Propiolic Acid. Hepto-acetic Ester.
(8) Finally, certain syntheses have been performed, in isolated cases, from
aldehydes and diazoacetic ester (p. 405) (B. 40, 3000) :
CCl3CHO+NaCHC02C2H5
Reactions of the ^-Ketonic Esters.
(la) On heating the mono- or di-alkyl acetoacetic esters with
alkalis in dilute aqueous or alcoholic solution, or with barium hydroxide,
they decompose after the manner of acetoacetic esters (p. 417), forming
ketones (alkyl acetones) (ketone decomposition) :
CH.CHCOaCaH. CH3CH
+2ROH= |
)CH8 COCH,
(CH8)aCC02C2H5 (CH3)2CH
+2KOH= I +K2C08+CtH,OH.
COCH, COCH3
(ib) At the same time another cleavage takes place, by which
mono- and di-alkylacetic acids are formed along with acetic acid (acid
decomposition) :
+2ROH= | +KaC08-f-C2H5OH
COCH, CC
CH8.CHCO2CaH. CH3CH2C02K
+2KOH=.-
COCH8 CH8C02K
(CH8)aC.C02C2H, (CH8)aCHCO2K
| -r-2KOH= -fC2H6OH
COCH3 CH8COaK
Both of these reactions, in which decomposition occurs (the cleavage of ketone
and of acid), usually take place simultaneously. In using dilute potassium or
barium hydroxide solution, the ketone-decomposition predominates, whereas,
with very concentrated alcoholic potassium hydroxide, the acid-decomposition
mainly takes place (/. Wislicenus, A. 190, 276). The production of ketone, with
elimination of CO2, occurs almost exclusively on boiling with sulphuric or hydro-
chloric acid (i part acid and 2 parts water).
4I6 ORGANIC CHEMISTRY
This breaking-down of the mono- and di-alkyl acetoacetic esters is the basis
of the application of these bodies in the production of mono- and di-alkyl acetones
(p. 218), as well as mono- and dialkyl acetic acids.
(ic) The decomposition of mono- and di-alkyl-acetoacetic esters
into mono- and di-acetic esters can be carried out directly and com-
pletely by boiling with sodium ethoxide solution (ester decomposition)
(B. 33, 2670 ; 41, 1260) :
CH3CO.C(CH3)aC02R+ROH=CH3C02R + (CH3)2CHC02R.
(2) The acetoacetic esters are converted by nascent hydrogeT
(sodium amalgam) into the corresponding j8-hydroxy-acids (p. 358) :
CH8CO.CH2C02C2H6+H2+H20=CH3CH(OH).CHaCOtH+C,lH6OH.
They are hydrolyzed at the same time.
(3) Chlorine and bromine produce halogen substitution products of the aceto-
acetic esters.
(4) PCI 6 replaces the oxygen of the j8-CO group by 2 atoms of chlorine. The
chloride, CH3CC12.CH2COC1, readily loses hydrochloric acid and yields two
chlorocrotonic acids (p. 295).
(5) Orthoformic ester replaces the oxygen of the j8-CO group by two ethoxy-
groups producing jS-diethyl butyric ester, which readily splits ofl alcohol and
yields j8-ethoxycrotonic ester (p. 418).
(6) Ammonia, aniline, hydrazine and phenylhydrazine acting on acetoacetic
ester produce the imine, anilide, hydra zone and phenylhydrazone, which can also
be looked on as being respectively /J-amino-, j3-anilino-, jS-hydrazino-, and jS-
phenylhydrazino-cro tonic esters. The acetoacetic ester forms the semicarbazide
with semicarbazone, and the oxime with hydroxylamine (B. 28, 2731). The
hydrazones and oximes of the j3-ketonic esters easily give up alcohol and become
converted into cyclic derivatives — lactazams and lactazones (comp. p. 406),
usually known as pyrazolones and isoxazoles :
C8H5N N O N
I II I II
CO.CH2CCH8 CO.CH2.C.CH,
Phenyl Methyl Pyrazolone. Methyl Isoxarole.
One molecule of hydrazine converts acetoacetic ester into the azint,
(C6H10O2) :N— N: (C,H10O2), m.p. 48°, which an excess of hydrazine easily
transforms into two molecules of methyl pyrazolone (B. 37, 2820 ; 38, 3036).
(7) Nitric oxide and sodium ethoxide change sodium acetoacetic ester into
the disodium derivative of isonitramine acetoacetic ester (A. 300, 89) :
COaC2H6v COaC2H6v /N202Na
>CHNa+2NO+C2H5ONa= >C< +C1H.OH.
CH.CCT CH3CCX XNa
(8) Nitrous acid changes the non-alkylated acetoacetic ester to the isonitroso-
derivatives, CH3CO.C(N.OH)CO2R, which readily break up into isonitroso-
acetone, CO2 and alcohols (see below). Nitrous acid, acting on mono-alkyl
acetoacetic esters, displaces the acetyl group and leads to the formation of
a-isonitroso-fatty acids (p. 410), whereas the free monoalkyl acetoacetic esters,
under like treatment, split off CO2 and yield isonitroso-ketones (p. 354).
(9) Benzene diazo-salts act on acetoacetic ester similarly to nitrous acid
(B. 21, 549 ; A. 247, 217).
(10) Diazomethane converts acetoacetic ester into J3-methoxy-cro tonic ester
(p. 418) (B. 28, 1626).
(n) An important reaction is the union of acetoacetic ester with urea, when
NH-CO-NH
water is eliminated and Methyl Uracil, | | , is formed. This is
CH3.C CH-CO
the parent substance in the synthesis of uric acid (q.v.).
ACETOACETIC ETHYL ESTER 417
(12) Amidines convert acetoacetic ester into pyrimidine compounds (Vol. II.).
(13) The action of sulphur chloride or thionyl chloride on acetoacetic ester is
to produce thiodiacetoacetic ester S[CH(COCH3)CO2C2H6]2 (B. 39, 3255).
Nucleus-synthetic Reactions.
(1) Heated alone, acetoacetic ester is changed to dehydracetic acid (q.v.), the
S-lactone of an unsaturated 8-hydroxy-diketone carboxylic acid.
(2) The action of sulphuric acid causes acetoacetic ester to pass into a con-
densation product, isodehydracetic acid, the 8-lactone of an unsaturated
8-hydroxy-dicarboxylic acid.
(3) Hydrocyanic acid unites with acetoacetic ester, forming the nitrile of
a-methyl malic ester.
(4) (For the action of magnesium alkyl iodides on acetoacetic ester, comp.
C. 1902, I. 1197.)
The nucleus-synthetic reactions of sodium acetoacetic ester and
copper acetoacetic ester are far more numerous.
(5) It has been repeatedly mentioned that the sodium acetoacetic
esters could be applied in the building-up of the mono- and di-alkyl
acetoacetic esters, and also, therefore, in the preparation of mono-
and di-alkyl acetones, as well as mono- and di-alkyl acetic acids.
(6) Iodine converts sodium acetoacetic ester into diacetosuccinic ester :
CH3CO.CHCO2C2H,
CH3CO.CHC02C2H,'
This body is also produced in the electrolysis of sodium acetoacetic ester (B. 28,
R. 452).
(7) Chloroform and sodium acetoacetic ester unite to form hydroxyuvitic
acid, C,H2(CH8)(OH)(CO2H)a.
(8) Furthermore, monochlor acetone, cyanogen chloride, acid halides,
and monohalogen substitution products of mono- and di-carboxylic esters
• react with sodium acetoacetic ester. Copper acetoacetic ester is most
advantageously used with phosgene (B. 19, 19). (For greater detail
see below.)
(9) Aldehydes, e.g. acetaldehyde, and acetoacetic ester unite to form ethyl-
idene mono- and ethylidene bisacetoacetic esters. The latter y-diketones espe-
cially are important, because by an intramolecular change, causing the loss
of water from CO and CH3, they condense to keto-hydrobenzene derivatives
(A. 288, 323), and with ammonia yield hydropyridine bodies. Acetone condenses
with acetoacetic ester, forming isopropylidene acetoacetic ester (p. 425) (B. 30,
481).
(10) Acetoacetic ester condenses similarly with orthoformic ester to the
ethoxymethylene derivative (C9H8O2) : CHOC2H5, and to the methylene deriva-
tive (C,H,O3) : CH.(C,H,O3) (B. 26, 2729).
(n) Dicyanogen unites with sodium acetoacetic ester, forming the sodium
compound of a-acetyl ft-cyano-ft-iminopropionic ester, and of a^a-diacetyl /3jj8-
diimino-adipic ester (B. 35, 4142) :
(12) Phenols condense with acetoacetic ester to form coumarines (Vol. II.)
: (B. 29, 1794) ; quinones (Vol. II.) form cumarones.
Acetoacetic Ethyl Ester, Acetoacetic Ester, C6H10O3=CH3CO.CH2-
CO2C2H5, b.p.760 181°, b.p.12 72°, is a pleasantly smelling liquid,
D20 =1-0256. The ester is only slightly soluble in water, it distils
readily in steam. Ferric chloride colours it violet.
VOL. I. 2 E
4I8 ORGANIC CHEMISTRY
Boiling alkalis or acids convert the ester into acetone, carbon
dioxide and alcohol. In addition to its formation by the action of
sodium sodium amide, or sodium ethoxide on acetic ethyl ester,
it results by the partial decomposition of acetone dicarboxyhc ester
(q.v.), C02C2H5.CH2COCH2.C02C2H5.
Acetoacetic Methyl Ester, b.p. 169°.
The sodium salt, CH3(CONa) : CHCOaC2H5, crystallizes in long needles.
Copper salt, (C6H,Os)2Cu, is produced when a copper acetate solution is shaken
with an alcoholic solution of acetoacetic ester. When boiled with methyl alcohol,
it undergoes alcoholysis, and is converted into (C,H9O8)CuOCH3 (B. 35, 539) ;
aluminium salt, m.p. 80°, b.p.8 194° (C. 1900, I. u).
Homologous fi-Ketonic Acid Esters :
Methyl Acetoacetic Methyl Ester . CH3COCH(CH,)COaCH8 b.p. 169°
ethyl ester, b.p. 187°.
Ethyl Acetoacetio Methyl Ester . . CHgCOCHfCjHJCOjCH, „ 190*
ethyl ester, b.p. 198*.
Dimethyl Acetoacetic Ethyl Ester . CH3COC(CH3)2CO2C2H5 „ 184°) Mode of
Methyl Ethyl Acetoacetic Ester . CH8COC(CH3)(C2H5)COaR „ 198° formation
Propyl Acetoacetic Ester . . . CHSCOCH(C,HT)CO,R ,,208° No. 2
Diethyl Acetoacetic Ester . . . CH3COC(C2H6)2CO2R „ 218° J (p. 413).
Propionyl Acetic Ester .... CH,CHaCOCH2COaR, b.p.17 92° (mode of
formation 3 and 56).
Propionyl Propionic Ester . . . CH8CHaCOCH(CH,)COaR, b.p. 196° (mode
of formation i, 4, and 6).
Butyryl Acetic Methyl Ester . . CH8CHaCH2COCH2CO2CH8, b.p.14 85° (mode
of formation 3, 56, and 7).
Butyryl Butyric Ester . . . . C3H7COCH(C2H5)CO2R, b.p. 223° (mode of
formation 4 and 6).
Butyryl Isobutyric Ester . . . C3H7COC(CH8)2CO2R, b.p.a, 109° (mode of
formation 50).
Isobutyryl Isobutyric Ester . . . (CH8)aCHCOC(CH8)2COaR, b.p. 203° (mode
of formation 4).
Decanoyl Acetic Ester . . . . C9H,9COCH2CO2R, b.p.x, 165° (mode of
formation 7).
The enol- (pseudo-, aci-) form of the above derivatives of acetoacetic acid are
to be derived from the corresponding keto- forms.
Ethers and Thio-ethers of the jS-Ketonic Acid Esters: p-Diethoxybutyric
Ester, Ortho-ethyl Ether of Acetoacetic Ester, CH3C(OC2H6)2CH2CO2C2H6, is
obtained by the inter-reaction at low temperatures of acetoacetic and ortho-
formic esters under the influence of various reagents (comp. pp. 412, 417). It
is an oil, which is converted by saponification into the crystallizable sodium salt
of ft-diethoxybutyric acid. This readily gives up CO2, and becomes changed into
acetone ortho-ethyl ether (p. 225). The diethoxybutyric acid ester decomposes
on distillation into alcohol and fi-Ethoxycrotonic Ester, ethyl ether of aci-acetoacetic
ester, CH3C(OC2H5) : CHCO2C2H6, m.p. 30°, b.p. 195°. This, on saponification,
yields ft-Ethoxycrotonic Acid, m.p. 137°; it can also be formed from sodium ethoxide
and jS-chlorocrotonic acid (p. 295), and also from acetoacetic ester. On heating,
it loses CO2 and is converted into isopropenyl ethyl ether (p. 129) (A. 219, 327 ;
256, 205). Alcoholic sodium ethoxide changes ethoxycrotonic ester back 'into
di-ethoxybutyric ester (B. 29, 1007). fi-M ethoxycrotonic Ester, CH3C(OCH8) :
CHCOaCaH5, m.p. 1 88°, is formed from acetoacetic ester and diazomethane
(B. 28, 1627).
A mixture of the two types of ethers — the ethyl ether of the aci- form and
the ortho-ether of the keto- form of the jS-ketonic esters — are obtained by boil-
ing the homologous propiolic acid ester (p. 303) with alcoholic potassium
hydroxide :
RC;CCOaCaH, > RC(OC,H8) : CHCOaCaH6 •<-> RC(pCaH,)a.CHaCOaCaH6.
Similarly, propiolic nitrile yields the ether of the hetonic acid nitrile (C. 1904, 1. 659 ;
1506, I. 912).
The aci-ether is readily hydrolyzed by dilute sulphuric acid into the fl-ketone
acid ether.
NITROGEN DERIVATIVES OF |$-KETONIC ACIDS 419
p-Ditkioctkyl Butyric Es^,CH3C(SC2TT5)2CH2CO2C2H5, b.p.?7 138°, is decom-
posed by hydrolysis into mercaptan SLudfi-Thioethyl Crotonic Acid, CH3C(SC2H6) :
CHCO2H, m.p. 91° (B. 33, 2801 ; 34, 2634).
Esters of the aci-/?-Ketonic Acid Esters.
Acid chlorides and also halogen alkyls, acting on sodium acetoacetic ester,
produce mainly the C-acyl compounds (described later among the diketo-carboxylic
esters). Some O-acyl ester is also formed, which can be obtained as a main product,
by the action of acid chlorides on acetoacetic ester in the presence of pyridine.
The O-acyl esters are insoluble in alkalis, whilst the C-acyl esters are soluble, thus
providing an easy method of separation. When heated with alkalis (potassium
carbonate, sodium acetoacetic ester, etc.), the O-acyl esters are transformed into
C-acyl esters. By heating to 240°, O-acetyl acetoacetic ester is converted to a
small extent into di- acetoacetic ester (B. 38, 546) :
CH3C(OCOCH3)=CHC02C2H6 > CH3CO-CH(COCH3)CO2C2H5.
Chlorocarbonic ester and sodium acetoacetic ester produce almost entirely
carbethoxyl hydroxycrotonic ester, whilst with the copper salt acetyl malonic
ester is formed (B. 37, 3394). Both sodium and copper acetoacetic esters yield
Acetyl Malonanilic Acid Ester, CH3COCH(CONHC6H5)CO2C2H5 (B. 37, 4627 ;
38, 22). It is therefore difficult to formulate a law for the acylation of these
esters.
0- Acetyl Acetoacetic Ester, fi-Acetoxycrotonic Ester, CH3C(OCOCH3) : CHCO2-
C2H5, b.p.12 98°; methyl ester, b.p. 95°. O-Butyryl Acetoacetic Methyl Ester,
b.p. 10 I05°- 0-Propionyl Acetoacetic Ethyl Ester, b.p.12 106° *(C. 1902, II. 1411) ;
0-benzoyl ester, m.p. 43°.
0-Carboxethyl Acetoacetic Ester, p-Carboxethyl Hydroxycrotonic Ester. CH3C-
(OC02C2H6) : CHC02C2H6, b.p.14 131°.
Nitrogen Derivatives of jS-Ketone Carboxylie Acid.
Amides.
Aqueous ammonia acting on acetoacetic ester produces jS-aminocro tonic
ester (below), and Acetoacetic Amide, CH3COCH2CONH2, m.p. 50°, which forms a
crystalline copper salt (B. 35, 583). Methyl Acetoacetic Amide, CH3CO.CH(CHS)-
CONH2, m.p. 73°, and Ethyl Acetoacetic Amide, m.p. 96°, are prepared respec-
tively from methyl and ethyl acetoacetic ester, and ammonia (A. 257, 213).
Similarly, dimethyl and methyl ethyl acetoacetic ester form amides, m.p. 121°
and 124° respectively ; di-ethyl acetoacetic ester does not form an amide (C. 1907,
I. 401).
Nitriles.
Cyanaceione : Acetoacetic Acid Nitrile, CH2CO.CH2CN, b.p. 120-125°, is pre-
pared from imino-acetoacetic nitrile (see below) and hydrochloric acid ; also by
the transformation of a-methyl isoxazole (p. 354) (B. 25, 1787). It cannot be
obtained from chloracetone and KCN. On heating it polymerizes suddenly.
Chlorethyl methyl ketone and chlormethyl ethyl ketone (p. 342) do, however,
react with potassium cyanide to form a-M ethyl Acetoacetic Nitrile, CH3COCH-
(CH8)CN, b.p. 146° and Propionyl Acetonitrile, CH8CH2COCH2CN, b.p. 165°
(C. 1900, I. 1123 ; 1901, I. 96).
The reaction of aniline, hydrazine, phenylhydrazine and semicarbazide,
hydroxylamine, nitrous acid, nitric oxide, diazomethane, benzene, diazo-salts,
; urea and the amidines, with j8-keto-carboxylic esters are comparable to those on
pp. 416, 417 (Nos. 6-13), in which the formation of pyrozalones or lactazams from
the j3-keto-acid esters and the hydrazines is again to be remarked ; see Phenyl
Methyl Pyrazolone and Antipyrine (Vol. II.). A more detailed description is
given in connection with aminocrotonic ester.
fi-Aminocrotonic Ester or Imino-acetoacetic Ester, CH3C(NH2) : CHCO2C,H6,
or CH3C(NH)CH2CO2C2H5, two modifications, m.ps. 20° and 33° (A. 314, 202),
is prepared from acetoacetic ester or /3-chlorocrotonic ester (p. 295) and ammonia
(B. 28, R. 927). Aqueous hydrochloric acid converts it back into acetoacetic
ester. Hydrochloric acid gas forms a salt which is decomposed by heat at 130*
into ammonium chloride and 8-olefine lactone carboxylic ester, pseudo-lutido-
styril carboxylic ester (B. 20, 445 ; A. 236, 292 ; 259, 172). NaCIO and NaBrO
produce chlor- and brom-amino- crotonic ester, CH3C(NHX) : CHCO2R, which, on
treatment with acids, lose NH3, and are converted into a-chlor- and a-brom»
420 ORGANIC CHEMISTRY
acetoacetic ester (A. 318, 371). On the action of nitrous acid, see B. 37, 47.
Phenyl cyanate and mustard oil combine with aminocrotonic ester, and form a
series of N- and C- derivatives (A. 314, 209 ; 344, 19) :
(C«H5NHCO).NHCCH8 NH2CCH,
and
HCCOaC2H,
(RNHCS).NHCCH3 NH2CCH,
and
HCC02C2H6 (RNHCS).CC02CaH5
P-Aminocrotonic Acid Nitrite, Imino-acetoacetic Nitrite, CH3C(NHa): CHCN
or CH3C(NH).CH2CN, m.p. 52°, results from the condensation of two molecules
of acetonitrile by means of metallic sodium (J. pr. Ch. [2] 52, 81).
Homologous fi-alkylamino- and fi-di-alkylamino-acrylic esters, (CaH8)aNCR :-
CCO2CaH5, and nitrites, CaH6CH2NHCR : CHCN, are prepared by the addition
of amines to the homologous propiolic esters and nitriles. Acids easily decompose
them into the j8-ketonic acid esters or nitriles, and amines (C. 1907, I. 25). Di-
nitrocaproic Acid, CH3C(NOa)aC(CH3)2CO2H, m.p. 215° with decomposition, is
formed when camphor is boiled for a long time with nitric acid. It can be looked
on as being a derivative of a-dimethyl acetoacetic acid (B. 26, 3051).
Halogen Substitution Products of the /3-KetonIc Esters.
Chlorine alone or in the presence of sulphuryl chloride acting on acetoacetic
ester replaces the hydrogen atoms both of the CHa and CH3 groups by chlorine.
The hydrogen of the CH2 group is first substituted.
a-Chloracetoaeetic Ester. CH3COCHC1CO2C2H5, b.p.10 109°, possesses a
penetrating odour. y-Chloracetoacetic Ester, ClCHaCOCH2CO2C2H5, b.p.n 105°,
is prepared by the oxidation of y-chloro-/?-hydroxybutyric ester with chromic
acid ; also synthetically, from chloroacetic ester and aluminium amalgam (comp.
method of formation 4, p. 414). Copper salt, m.p. 168° with decomposition,
forms green crystals (C. 1904, I. 788 ; 1907, I. 944). a-Bromacetoacetic Ester,
CH3CO.CHBr.CO2C2H6, b.p.12 101-104°, is obtained from acetoacetic ester and
bromine in the cold (B. 36, 1730). HBr converts it gradually into y-Brom-
acetoacetic Ester, CH2Br.CO.CH2CO2C2H6, b.p., 125° (B. 29, 1042). This substance
is also formed from bromacetic ester and magnesium (B. 41, 954).
The constitution of these two bodies has been established by condensing them
with thiourea to the corresponding thiazole derivatives.
aa-Dienloraeetoaeetic Ester, CH3COCC12CO2C2H6, b.p. 205°, is a pungent-
smelling liquid. Heated with HC1 it decomposes into a-dichloracetone, CH3-
COCHClj, alcohol, and CO2 ; with alkalis it yields acetic and dichloracetic acids.
aa-Dibromacetoacetic Ester is a liquid; dioxime, CH3C(NOH)C(NOH)CO2C2H5,
m.p. 142°. ay-Dibromacetoacetic Ester, CH2Br.CO.CHBr.CO2CaH5, m.p. 45-
49°.
According to Demarfay (B. 13, 1479, 1870) the y-mono-bromo-mono-alkyl-
acetoacetic esters, when heated alone or with water, split off ethyl bromide and
yield peculiar acids ; thus, bromomethyl acetoacetic ester gave Tetrinic Acid
or Methyl Tetronic Acid, whilst bromethyl acetoacetic ester yielded Pentinic Acid
or Ethyl Tetronic Acid (L. Wolff, A. 291, 226) :
CO.CHaBr -CaH.Br C(OH).CHav
I > II >0
CH3.CH.CO.O.C2H, CH3C CO/
Tetrinic Acid=Metbyl Tetronic Acid.
These acids will be discussed later as lactones of hydroxy-ketonic acids,
together with the oxidation products of triacid alcohols.
The y-dibromo-mono-alkyl acetoacetic esters, treated with alcoholic potassium
hvdroxide, yield hydroxytetrinic acid, hydroxypentinic acid, etc. Gorbow
(B. 21, R. 180) found them to be homologues of fumaric acid. Hydroxytetrinic
acid is mesaconic acid (q.v.) ; whilst hydroxypentinic acid is ethyl fumaric acid
(q.v.), etc.
The formation of these olefine dicarboxylic acids from y y-dibromo-mono-
alkyl acetoacetic esters is easily explained on the assumption that the kftto- or
UEVULINIC ACID 421
aldehyde acids are first formed, which are then converted into the unsaturated
dicarboxylic acids :
CHBr, CHO ^ COOH
:O.CH(CH3)C02R CO.CH(CH3)CO2R CH : C(CH3)CO2R
The y-bromo-dialkyl acetoacetic esters, however, behave differently, giving
rise to lactones oi y-hydroxy-/J-ketone carboxylic acids (Conrad and Gas/). The
bromine atom of the y-bromo-dimethyl-acetoacetic ester (i, see diagrammatic repre-
sentation below), can be replaced by acetoxyl (2), producing the y-acetoxy-
dimethyl-acetoacetic ester, which gives up methyl acetate and changes into
y-hydroxy-dimethyl-acetoacetic acid lactone (3). Bromine, entering the molecule
of the y-acetoxy-dimethyl-acetoacetic ester, becomes attached to the y-carbon
atom, producing a compound which has not been isolated. The action of water
on this is the immediate production of the lactone of y-dihydroxy-dimethyl-aceto-
acetic acid (4). Its salts are those of an aldehyde-ketone-carboxylic acid, which
is converted by alkalis into ft-dimeihyl malic acid ( 5) ; whilst on fusion a keto-
aldehyde — isobutyryl formaldehyde (p. 348) — is formed (6). The inter-relations
of these compounds are shown as follows (B. 31, 2726, 2954) •
CH2— CO— C(CH3)a CH2— CO— C(CHa).
(I) I I > I I (2)
' Br CH3OCO _, O CO
I
CH,— CO— C(CHj), Br HOCH— CO— C(CH3),
(3) OCOCH COCH ~^*- M
vJHJU.H.3 LxLJaUrl3
OCH— CO.CH(CH8)2^ t HOCO— CH(OH)— C(CH,)a
(6) I (5)
+C0a HOCO
The action of ammonia on y-bromo-dimethyl-acetoacetic ester is to form the
lactam of y-amino-dimethyl-acetoacetic acid — dimethyl ketopyrrolidone —
which is broken down by hydrochloric acid into amino-dimethyl-acetone (p. 344)
(B. 32, 1199).
y-Trichloracetoacetic Ester, CC13COCH2CO2C2H6, b.p. 234°, is also prepared
synthetically from chloral and diazoacetic ester (p. 404) (B. 40, 3001).
III. y-Ketonic Acids.
These acids are distinguished from the acids of the j8-variety by
the fact that when heated they do not yield CO2, but split off water
and pass into unsaturated y-lactones. They form y-hydroxy-acids on
reduction, which readily pass into saturated y-lactones. An in-
teresting fact in this connection is that they yield remarkably well
crystallized acetyl derivatives when treated with acetic anhydride.
This reaction, as well as the production of unsaturated y-lactones,
on distillation, argues for the view that the y-ketonic acids are y-oxy-
lactones :
i,.CO.CH2.CH2 CH,.C(OH).CHa.CH2 CH8.C(OOC.CH3)CH2CHa CH,.C:CH.CHa
* ft I or | | > \ | > I
COOH O CO O CO O CO.
Laevulinic Acid. Acetyl Laavulinic Acid. a-Angelica Lactone.
Lsevulinic Acid, j3-Acetopropionic Acid, y-Ketovaleric Acid, or y-
Oxovaleric Acid [>Pentanone Acid], C5H8O3=CH3.CO.CH2.CH2.CO2H,
or CH3.C(OH).CH2.CH2COO, m.p. 32-5°; b.p.12 144°, b.p.7e0 239°
with slight decomposition, is isomeric with methyl acetoacetic acid,
422 ORGANIC CHEMISTRY
which may be designated a-acetopropionic acid. Lsevulinic acid
can be obtained from the hexoses (q.v.) on boiling them with
dilute hydrochloric or sulphuric acid. It is more easily obtained
(i) from laevulose— hence the name— than from dextrose. It is pre-
pared by heating sucrose or starch with hydrochloric acid (B. 19, 707,
2572 • 20, 1775 ; A. 227, 99). Its constitution is evident from its
direct and also indirect syntheses ; (2) from the mono-ethyl ester of
succinyl monochloride, C1CO.CH2.CH2CO2C2H5, and zinc methyl (C.
1899, II. 418) ; and by boiling the reaction-product of chloracetic
ester' and sodium acetoacetic ester — acetosuccinic ester — with hydro-
chloric acid or barium hydroxide solution (Conrad, A. 188, 223) :
CHtCO.CH2 C1CH2C02C2H, CH,CO.CH.CH2.C02CaH, HOCH,CO.OI,OI,CO,H
io2C2H^ N^~~ CO,C,H'f C02
It is furthermore obtained (3) by the action of concentrated H2S04
on methyl glutolactonic acid, CH3C(CO2H)CH2CH2COO ; (4) by
the oxidation of its corresponding ^-acetopropyl alcohol (p. 342),
(5) by the oxidation of methyl heptenone (p. 232), of linalool and
geraniol, two bodies belonging to the group of olefine terpenes. Also,
by hydrolysis of crotonaldehyde cyanohydrin with warm hydrochloric
acid and the transformation of the propenyl glycollic acid thus formed
(p. 397).
Laevulinic acid dissolves very readily in water, alcohol and ether,
and undergoes the following changes : (i) By slow distillation under
the ordinary pressure it breaks down into water and a- and £- angelic
lactones (p. 398). (2) When heated to 150-200° with hydriodic acid
and phosphorus, laevulinic acid is changed to n-valeric acid. (3) By
the action of sodium amalgam sodium y-hydroxyvalerate is produced,
the acid from which changes into y-valerolactone. (4) Dilute nitric
acid converts laevulinic acid partly into acetic and malonic acid and
partly into succinic acid and carbon dioxide. The action of sunlight
on an aqueous solution of the acid is to produce a certain quantity of
methyl alcohol, formic and propionic acids (B. 40, 2417).
(5) Bromine converts the acid into substitution products (p. 423).
(6) lodic acid changes it to bi-iodo-acetacrylic acid. (7) P2S3 converts it into
thiotolene, C4H3S.CH3 (Vol. II.). For the behaviour of laevulinic acid with
hydroxylamine and phenylhydrazine consult the paragraph relating to the
nitrogen derivatives of the y-ketonic acids.
Nucleus-synthetic Reactions : (8) Hydrocyanic acid and laevulinic acid yield
the nitrile of methyl glutolactonic acid: CH,.C(CN)CH2CH8COO (see above).
(9) Benzaldehyde and lasvulinic acid condense in acid solution to fi-benzal Icevulinic
acid, and in alkaline solution to B-benzal Icevulinic acid (A. 258, 129 ; B. 26, 349).
10) Electrolysis of potassium laevulinate results in the production of i,4~di-
acetyl butane (p. 352) (B. 33, 155).
Laevulinic Acid Derivatives.— The calcium salt, (C6H7O3)2Ca-f 2H2O ; silver
salt, C5H7O3Ag, is a characteristic, crystalline precipitate, dissolving in water
with difficulty ; methyl ester, C6H7(CH3)O3, b.p. 191° ; ethyl ester, b.p. 200°.
CHSCOO\ /OCO
Acetyl Lavuhnic Acid, y-Acetoxyl, y-Valerolactone, \f I »
CH3CCH2CH2
m-P.. ?8 , is particularly noteworthy. It is formed from Isevulinic acid and
acetic anhydride ; from silver laevulinate and acetyl chloride ; from laevulinic
HOMOLOGOUS L^VULINIC ACIDS 423
chloride and silver acetate ; as well as from a-angelic lactone and acetic acid.
The last method of formation, as well as the formation of a- and jS-angelic
lactone by heating acetolaevulinic acid are most easily understood upon the
assumption that the constitution is really as indicated in the formula shown
above (A. 256, 314). , 1
LcBvulinic Chloride, y-Chlorovalerolactone, CH3CC1CH2CH2COO, b.p.^ 80°,
is produced by the addition of HC1 to a-angelic lactone, and by the action of
acetyl chloride on laevulinic acid (A. 256, 334). Lcevulin amide, y-Amido-
valerolactone, CH8C(NH2)CH2CH2COO, has been obtained from laevulinic ester,
and from a-angelic lactone and ammonia (A. 229, 249).
Homologous Lsevulinie Acids are obtained from the homologues of aceto-
succinic ester (p. 422) :
fi-Methyl Ltsvulinic Acid, fi-Acetobutyric. Acid, CH,CO.CH(CH8)CHaCO2H,
m.p. —12*, b.p. 242*, is prepared from a-methyl acetosuccinic ester. It forms
a difficultly soluble semicarbazone (C. 1900, II. 242), a-M ethyl Ltsvulinic Acid,
fi-Acetyl Isobutyric Acid, CHSCO.CH2CH(CH3)CO2H, m.p. 248°. Homolcevulinic
Acid, S-M ethyl Lcsvulinic Acid, CH8CH2CO.CH2CH2COOH, m.p. 32°, is obtained
f rom jSy-dibromocaproic acid (A. 268, 69), together with one of the hydroxy-capro-
lactones, a-Ethyl Ltsvulinic Acid, CH3CO.CHaCH(C2H6)CO,H, m.p. 250-252*.
Mesitonic Acid, aa-Dimethyl Lcsvulinic Acid, CH8CO.CH2C(CH8)aCO2H, m.p.
74°, b.p.! 5 138°, is obtained by the action of alcoholic potassium cyanide solution
on mesityl oxide, CH8C9CH : C(CH8)2 (p. 229). The nitrile, CH8COCH2-
(CH8)2CN, is formed as an intermediate product, and can be formed from mesityl
oxide hydrochloride by KCN. Mesityl oxide and hydrocyanic acid in excess
produce the cyanhydrin of mesitonic nitrile, the dinitrile of the so-called mesitylic
acid, which decomposes on being heated with hydrochloric acid into formic and
mesitonic acids (C. 1904, II. 1108 ; B. 37, 4070 ; A. 24-7, 90). Mesitonic acid is
converted into dimethyl malonic acid when oxidized with nitric acid.
ftp-Dimethyl Lcsvulinic Acid, CH8COC(CH8)2.CHaCO2H, b.p.18 151°, results
from a-unsym.-dimethyl succinyl chloride and zinc methyl (C. 1899, II. 524).
^-Dimethyl Lcsvulinic Acid, (CH8)2CH.CO.CH2CHaCOaH, m.p. 40°, is pre-
pared from the result of the double decomposition of y-bromo-dimethyl-acetoacetic
ester and sodium malonic ester, by heating it with dilute sulphuric acid (B. 80,
864) ; by oxidation of dimethyl acetonyl acetone (p. 252) (B. 31, 2311) ; from
dibrom-isoheptoic acid and soda solution (A. 288, 133} ; by oxidation of various
terpenes (Vol. II.), such as thujone.
^-Dimethyl Lcsvulinic Acid, CHsCHaCOCH(CH8)CH2COOH, b.p. 154°, is
produced from y-ethylidene /J-methyl butyrolactone, a degradation product of
dicrotonic acid (q.v.) ; also by the splitting up of oa-dimethyl acetone dicarbox-
ylic a-acetic ester (B. 33, 3323).
Caproyl Isobutyric Acid, C6HuCOCHaCH(CH8)COaH, m.p. 33°, b.p.$9 190°
(C. 1905, II. 1782).
Halogen y-Ketonic Acids.— a-Bromolcsvulinic Acid, CH8COCH2CHBrCO2H,
m.p. 79*, is produced when HBr acts on ^3-acetoacrylic acid. Boiling water
converts it into a-hydroxylaevulinic acid (q.v.).
fi-Brotnolcsvulinic Acid, CH8COCHBrCHaCO2H, m.p. 59°, is produced
in the bromination of laevulinic acid, as well as by the action of water on the
addition product of bromine and a-angelic lactone. Warming with sodium
hydroxide converts the jS-bromolasvulinic acid into a-hydroxylaevulinic acid and
/S-acetoacrylic acid*. Ammonia converts the j8-bromolaevulinic acid into tetra-
methyl pyrazine, whilst aniline produces pyrazine-2,3-dimethyl indole (B. 21,3360).
aft-Dibromolcsvulinic Acid, CH8COCHBrCHBrCO2H, m.p. 108°, is prepared
from jS-acetacrylic acid and Bra. fiS-Dibromolcevulinic Acid, CHaBrCOCHBr-
CH,COjH, m.p. 115°, is produced in the bromination of laevulinic acid. It yields
diacetyl and glyoxyl propionic acid, HOC.CO.CHaCH2CO2H, when it is boiled
with water. Concentrated nitric acid converts it into dibromodinitromethane
and monobromosuccinic acid, whilst with concentrated sulphuric acid it yields
two isomeric dibromo-diketo-R-pentenes (Vol. II.).
Nitrogen Derivatives of the y-Ketonic Acids.
(i) Lavulinamide, CH8COCHaCHaCONHa or CH8C(NHa)CHaCH,COO, m.p;
107° (see above).
ORGANIC CHEMISTRY
(2) Action of Hydrazine, NH2NH2 : Lesvulinic Hydrazide, CH,COCH2CH2-
CONHNH2, m.p. 82°. On the application of heat it passes into a lactazam
(p. 406)— ^-Methyl Pyridazolone, ^-Methyl Pyridazinone, CH,(C=N.NH)CH1-
CH .CO, m.p. 94° (B. 26,408; J. pr. Ch. [2] 50, 522).
(3) Action of Phenylhydrazine, NH2NHC,H5 : The first product is a hydra-
zone' which yields a lactazam when heated. Lavulinic Phenylhydrazone, CHSC( =
NNHC.HB)CH2CH2CO2H, m.p. 108°. This passes into ^-Methyl Pkenyl Pyrida-
zolone, m.p. 81 ° (A. 253, 44). When fused with zinc chloride it becomes dimethyl-
indol acetic acid,
C6H4.CCH2COOK HOCO.CH2.CHf CO— CH2— CH2
NH-CCH, > C.H,NH.N:CCH3 + C,H6N N:CCH,
Methyl Indole Acetic Acid. Methyl Phenyl Pyridazolone.
Phenylhydrazone Mcsitonic Acid, Phenylhydrazone a-Dimethyl L&vulinic Acid,
CH,C(:NNHC6H6)CH2C(CH3)2C02H, m.p. 121-5°. It passes into ^-Methyl i-
Dimethyl n-Phenyl Pyridazolone, C,H5NN:C(CH,)CH2C(CH3)CO, m.p. 84° (A.
(4)° Action of Hydroxylamine : Lcevulinic Oxitne, CH3C(NOH)CH2CH2CO2H,
m.p. 95° (B. 25, 1930), undergoes rearrangement in presence of concentrated
CH 2COv
sulphuric acid into succinyl methylimide, j yNCHt.
IV. 8-Ketonic Acids.
Such acids have been prepared from acetyl glutaric acids (q.v.) by the cleavage
of CO2. On reduction they yield d-lactones (p. 375).
y-Acetobutyric Acid, CH8CO.CH2CH2CH2CO2H, m.p. 13°, b.p. 275°, is formed
by the oxidation of y-acetobutyl alcohol (p. 342) ; and from dihydroresorcinol by
barium hydroxide solution. Sodium ethoxide changes it back into dihydroresor-
cinol.
b.p.
m.p _ _
zinc methyl (C. 1899, II. 524) ; also fronfisolauronolic acid and jS-campholenic
acid by oxidation (C. 1897, I. 26). y-Butyrobutyric Acid, CH3CH2CH2CO.-
CH2CH2CH2CO2H, m.p. 34°, from coniine (Vol. II.) and H2Of.
Certain higher ketonic acids have been prepared by the oxidation of hydro-
aromatic compounds of the terpene group, and are important in determining the
constitution of the latter. Other ketonic acids result from the hydrolysis of
acetylene carboxylic acids by means of concentrated sulphuric acid. A case in
point is Ketostearic Acid, from stearolic acid (p. 304), which is produced on treating
oleic and elaidic di-bromides with alcoholic potassium hydroxide. See oleic
acid (p. 300) for the value of these ketonic acids in determining the constitu-
tion of theolefme and acetylene carbonic acids, which are closely related to them.
5-Isopropyl-heptane-2-oneAcid,p-Isopropyl 8- Acetyl Valeric Acid, CHSCO.CH2.-
CH2CH(C,H7)CH2CO2H, m.p. 40°, b.p.20 192°, is prepared from tetrahydrocar-
vone, (Vol. II.). 2, ^-Dimethyl-octane- $-one Acid, fi-Methyl S-Isobutyl Valeric
Acid, CH3CH(CH3)CO.CH2CH2CH(CH3)CH2CO2H, b.p.20 186°, is prepared from
menthone (Vol. II.). Undecanonic Acid, CH,CO[CH2]$CO2H (?), m.p. 49°, is
formed from undecolic acid (p. 304).
8-Ketostearic Acid, CH3[CH2]8CO[CH2]7CO2H, m.p. 83°, is obtained frorr
chloroketostearic acid (B. 29, 806), and is a transposition product of ricinoleic
acid (p. 302).
9-Ketostearic Acid, Oxostearic acid, CH3[CH2]7CO[CH2],CO2H, m.p. 76°,
is obtained from stearolic acid (p. 304) by the action of concentrated sulphuric
acid ; also by heating the salt of dihydroxystearic acid, produced by the oxidation
of this acid by KMnO4 (J. pr. Ch. [2] 71, 422). Consult oleic acid (p. 300) for
the decomposition of its oxime.
CARBONIC ACID 425
C. UNSATURATED KETONIC ACIDS. OLEFINE KETONIC ACIDS
fl-Ketonie Acids :
POPTT
Ethylidene Acetoacetic Ester, CH3CH:C<^Q ^ , b.p. 211°, results from
the action of hydrochloric acid, ammonia, diethylamine or piperidine on alde-
hyde and acetoacetic ester (A. 218, 172 ; B. 29, 172 ; 31, 735). Magnesium
methyl iodide converts it into a salt of isopropyl acetoacetic ester (C. 1902, 1. 1 197).
Isopropylidene Acetoacetic Ester, (CH3)aC: C<£Q*!j|H6, b.p. 215°, is prepared
from acetone and acetoacetic ester by the action of HC1 and then of quinoline (B.
30, 481).
Isoheptenoyl Acetic Acid, (CH3)aC: CCH2CH3COCHaCOaH, is prepared from
isohexenyl propiolic acid (method of formation 7, p. 415) ; ethyl ester, b.p.14
127-130° (C. 1903, I. 1019).
y-Ketonic Acids :
jS-Acetoacrylie Acid, CH3CO.CH:CHCO2H, m.p. 125°, is derived together
with jS-hydroxylaevulinic acid from ^S-bromolaevulinic acid, and also from chloral-
acetone upon digestion with a soda solution, It combines with HBr and with
bromine, forming ajS-dibromolaevulinic acid and a-bromolaevulinic acid (A. 264,
234). For constitution of /?-acetoacrylic acid, see B. 35, 1157.
p-Trichloracetoacrylic Acid, Trichlorophenomalic Acid, CC18CO.CH:CHCO,H,
or CCla.C(OH)CH:CHCOO, m.p. 131°, is obtained from benzene by the action
of potassium chlorate and sulphuric acid (A. 223, 170 ; 239, 176). It breaks
up into chloroform and maleic acid when boiled with barium hydroxide.
It yields Acetyl Trichlorophenomalic Acid, CC13C(OCOCH3)CH:CH.COO,
m.p. 86° (A. 254, 152), when treated with acetic anhydride. Perchloracetyl
Acrylic Acid, CC13COCC1 : CCl.COaH, m.p. 83-84° (B. 26, 511), and other chlori-
nated acetyl acrylic and acetyl methyl acrylic acids (B. 26, 1670), are formed
from the decomposition of benzene derivatives which have previously been
chlorinated.
__£-Acetyl Dibromacrylic Acid, CH3CO.CBr:CBrCOOH, or CH8.C(OH)CBr:CBr-
COO, m.p. 78°, results upon treating a-tribromothiotolene with nitric acid. Its
remarkably low conductivity points to a lactone formula (B. 24, 77 ; 26, R. 16).
8-Ketonic Acids. — Chlorinated 8-ketonic acids have been obtained from the
ketochlorides of resorcinol and orcinol, e.g., trichloracetyl trichlorocrotonic acid,
CC13CO.CC1 : CHCClaCO2H (B. 26, 317, 504, 1666).
CARBONIC ACID AND ITS DERIVATIVES
The salts and esters of carbonic acid are derived from carbonic
acid hydrate, CO(OH)2, which is unstable in the free state, and which
may be regarded also as hydroxyformic acid, HO.COOH. Its sym-
metrical structure distinguishes it, however, from the other hydroxy-
acids containing three atoms of oxygen. It is a weak dibasic acid and
constitutes the transition to the true dibasic dicarboxylic acids — hence
it will be treated separately.
On attempting to liberate the hydrated acid from carbonates by a
stronger acid, it breaks down, as almost always happens, when two
hydroxyl groups are attached to the same carbon atom. A molecule
of water separates, and carbon dioxide, CO2, the anhydride of carbonic
acid, is set free. The carbonates recall the sulphites in their behaviour,
and carbon dioxide reminds us of sulphur dioxide or sulphurous anhy-
dride.
426 ORGANIC CHEMISTRY
Every carbon compound, containing an atom of carbon in double
union with an oxygen atom, may be regarded as the anhydride of a
dihydroxyl body corresponding with it. The hydrate formula, C=O-
(OH)2, of carbonic acid may be viewed as the formula of an anhydride
of the compound C(OH)4. Of course a compound of this form will
be as unstable as orthoformic acid, HC(OH)3 (p. 235). However,
esters derived from the formula C(OH)4, can actually be prepared ;
they are the orthocarbonic esters. In a broader sense, all methane
derivatives, in which the four hydrogen atoms have been replaced by
four univalent elements or residues, must be considered as derivatives
of orthocarbonic acid, e.g. tetrachloro-, tetrabromo-, tetra-iodo-, and
tetrafluoro-methane. From this point of view tetrachloromethane
is the chloride of orthocarbonic acid. These compounds, together
with chloropicrin, CC13N02, bromopicrin, CBr3N02, bromonitroform,
CBr(NO2)3, and tetranitromethane, C(NO2)4, will be discussed later as
derivatives of orthocarbonic acid. The carbon tetramide is not
known. Ammonia appears most frequently in the reactions where it
might well be expected, and also guanidine, which sustains the same
relation to the hypothetical carbon tetramide — the amide of ortho-
carbonic acid, as metacarbonic acid bears to the ortho-acid :
H§>c<8H H§>C=° °=c=°
Orthocarbonic Acid, Metacarbonic Acid, Carbon Dioxide,
(does not exist). (does not exist). Carbonic Acid Anhydride^
HaN.. r^NHa H2Nv~ ^JTT
H2N>C<-NH2 H2N>L
•Amide of Orthocarbonic Acid Guanidine.
(does not exist).
Carbon Monoxide, CO, the first oxidation product of carbon, was
described immediately after formic acid (p. 247). When carbon
is oxidized, the temperature determines whether carbon monoxide
or dioxide shall be formed : at a high temperature only the monoxide
is formed, the carbon behaving as a di-valent element.
Carbon Dioxide, C02, is the final combustion product of carbon.
Under favourable conditions the carbon of every organic substance
will be converted into it. In the quantitative analysis of carbon
derivatives carbon is determined in the form of CO2 (p. 3).
Liquid carbon dioxide is a good solvent for many organic substances,
especially those that are more volatile, a behaviour which resembles
the organic solvents (C. 1906, I. 1239).
Several of the methods for the formation of carbon dioxide, which are
especially important in organic chemistry, may be mentioned here.
Carbon dioxide is developed from fermentable sugars in the alcoholic
fermentation process (p. 112). It is readily formed by the oxidation
of formic acid (p. 238), into which it can be converted by reduction
(B. 28, R. 458) ; and can be withdrawn from the carboxylic acids,
i.e. from the acids containing carboxyl, — C<QH, when hydrogen will
enter where the carboxyl group was first attached. Those polycar-
boxylic acids, containing two carboxyl groups in union with each other,
or two and more carboxyls linked to the same carbon atom, readily
part with carbon dioxide on the application of heat. In the latter
DERIVATIVES OF CARBONIC ACID 427
case carboxylic acids result, in which each carboxyl remaining over is
attached to a particular carbon atom, e.g. :
Malonic Acid, HOaC.CHa.CO2H - > CO2+CH3.CO,H.
The j3-ketonic acids behave similarly (p. 410), e.g. :
Acetoacetic Acid, CH3COCH2.CO2H - > CO2 and CH8CO.CH3.
Monocarboxylic acids or their alkali salts can be deprived of C02
upon heating them with NaOH, when it is withdrawn as Na2CO3
(p. 72) :
CH3COaNa+NaOH=Na,CO8+CH4.
The electric current, acting on concentrated solutions of the alkali
salts of carboxylic acids, splits off carbon dioxide (p. 71), e.g. :
2CH3CO2K > CH8CH8+2COa and 2K.
The calcium salts of many carboxylic acids are decomposed by heat
with the production of calcium carbonate and ketones (p. 190), e.g. :
(CH3C02)2Ca > CaCO,+CH8COCHt.
These and similar reactions, in which CO2 readily separates from
rganic compounds, are of the first importance in the production of
he different classes of compounds. In contrast to the splitting-off of
CO2 in certain reactions we have its absorption by certain organic
metallic derivatives : nucleus-syntheses, in which carboxylic acids are
produced :
CH3MgI+CO2=CH3CO2MgI ; CH3C=CNa-fCOa=CH8C=CCO2Na;
C,H6ONa+COa=C6H4<Q^2Na (comp. Salicylic Acid, Vol. II.).
Esters of Metacarbonic Acid, or ordinary Carbonic Acid.
The primary esters of carbonic acid are not stable in a free con-
dition. They are prepared from the alcohols and carbon dioxide at
ow temperatures (B. 31, 3001).
Dumas and Peligot obtained the barium salt of methyl carbonic acid on
Conducting carbon dioxide into a methyl alcohol solution of anhydrous. barium
lydroxide (A. 35, 283).
Magnesium methoxide combines with COt to form magnesium methyl
arbonate (B. 30, 1836).
The potassium salt of Ethyl Carbonic Acid, CO<Q^aHc, separates in
>early scales on adding CO2 to the alcoholic solution of potassium alcoholate.
Vater decomposes it into potassium carbonate and alcohol.
The neutral esters appear (i) when the alkyl iodides act on silver
arbonate :
Iso (2) by treating esters of chloroformic acid with alcohols, whereby
lixed esters may also be obtained :
CH,OCOC1+HOC2H6=CH3OCO.OC2H5+HC1.
Methyl Ethyl Carbonate.
428 ORGANIC CHEMISTRY
This shows that, with application of heat, the higher alcohols are able to
expel the lower alcohols from the mixed esters :
C2H8OCOOCH3-fC2H6.OH=C2H6OCOOCaH8-fCHaOH.
Methyl Ethyl Ester. Diethyl Ester.
Hence, to obtain the mixed ester, the reaction must occur at a lower tempera-
ture.
As regards the nature of the product, it is immaterial as to what order is
pursued in introducing the alkyl groups, i.e. whether proceeding from chloro-
formic ester, we let ethyl alcohol act on it, or reverse the case, letting methyl
alcohol act on ethyl chloroformic ester ; the same methyl ethyl carbonic acid
results in each case (B. 13, 2417). This is an additional confirmation of the
like valence of the carbon affinities, already proved by numerous experiments
made with that direct object (with the mixed ketones) in view (p. 22) (C. 1901,
II. 219).
The neutral carbonic esters are ethereal smelling liquids, dissolving
readily in water. Excepting the dimethyl and the methyl ethyl ester, all
are lighter than water. With ammonia they first yield carbamic esters
and then urea. When they are heated with phosphorus pentachloride,
an alkyl group is eliminated, and in the case of the mixed esters this
is always the lower one, whilst the chloroformic esters constitute the
product :
C2H6OCOOCH3+PC16=C2H6OCOC1=POC13+CH3C1.
Carbonic esters are converted to carboxylic esters by alkyl and aryl-magnesium
halides (B. 38, 561).
Methyl Carbonic Ester, CO(OCH3)2, b.p. 91°, is produced from chloro-
formic ester by heating it with lead oxide; methyl ethyl ester, CH3OCOOC2H5,
b.p. 109°; diethyl ester, CO(OCaH6)2, b.p. 126°, is obtained from ethyl
oxalate, on warming with sodium or sodium ethoxide (with evolution of CO) ;
methyl propyl ester, b.p. 131°.
/OCH,
Glycol Carbonate, Carbonic Ethylene Ester, CO^ | , m.p. 39°, b.p. 236°, is
XOCH,
obtained from glycol and COC12.
Derivatives of Orthocarbonic Acid (p. 426).
Orthocarbonic Ester or Tetrabasic Carbonic Ester (Bassett, 1864, A. 132, 54%
is produced when sodium alcoholates act on chloropicrin :
CCl3(N02)+4C2H6ONa=C(OCaH6)4+3NaCl+NaNOa.
Orthocarbonic Ethyl Ester, C(OC2H5)4, b.p. 158°, is a liquid with an ethereal
odour. When heated with ammonia it yields guanidine (p. 455) and alcohol.
Alkyl and aryl magnesium halides convert it to ortho-carboxylic esters,
RC(CC2H6)3 (p. 284) (B. 38, 563).
The propyl ester, C(OC3H7)4, b.p. 224° ; isobutyl ester, b.p. 245°; methyl ester
apparently can not be prepared (A. 205, 254).
The tetrahalogen substitution products of methane appear to be
the halides corresponding with Orthocarbonic acid. They bear the
same relation to the Orthocarbonic esters that chloroform, bromoform
and iodoform sustain to the orthoformic esters. Indeed, tetrachloro-
and tetrabromomethane and sodium alcoholate do yield orthocar-
bonic esters, though with poor yield (B. 38, 563 ; C. 1906, I. 1691).
The formation of Orthocarbonic acid and trichloromethyl sulpho-
chloride (p. 434) by means of NaOC2H5, see C. 1908, I. 1041.
Methane Tetrahalogen Substitution Products :
Tetrafluoromethane, Carbon Tetrafluoride, CF4, is a colourless gas, condensable
by pressure. It is remarkable that this body belongs to that small class of
DERIVATIVES OF CARBONIC ACID 429
carbon derivatives which can be directly prepared from the elements. Finely
divided carbon, e.g. lamp black, combines directly with fluorine, with production
of light and heat.
Tetrachloromethane or Carbon Tetrachloride, CC14, solidifies —30°,
b.p. 76°, D0=i'63i, is formed (i) by the action of chlorine on chloro-
form in sunlight, or upon the addition of iodine, and (2) by action of
Cl on CS2 at 20-40°, C2C14 and C2C16 being formed at the same time
(B. 27, 3160) ; (3) upon heating CS2 with S2C12 in the presence of
small quantities of iron: CS2+2S2C12=CCU+6S (D. R. P. 72999).
Preparation of the pure substance, see C. 1899, II. 1098.
It is a pleasant-smelling liquid solidifying to a crystalline mass at
—30°. It is an excellent solvent for many substances, and is made
upon a technical scale. When heated with alcoholic KOH, it decom-
poses according to the following equation :
CCl4+6KOH = K2CO,4-3HaO+4KCl.
When the vapours are conducted through a red-hot tube, decomposition
occurs, and C8C14 and C2C18 are produced. This is an interesting reaction because,
as we have learned under acetic acid (p. 288), it plays a part in the first
synthesis of this long-known acid. C2C18 is produced from CC14 by means of
aluminium amalgam (p. 96). When carbon tetrachloride is digested with
phenols and sodium hydroxide, phenol carboxylic acids are produced (Vol. II.).
Tetrabro mo methane, CBr4, m.p. 92-5°, b.p. 189°, obtained by the action of
brom-iodide on bromoform or CS2, or of bromine and alkali on acetone and
other compounds (C. 1906, I. 1691)" crystallizes in shining plates.
Tetraiodomethane, CI4, D2p=4'32, is formed when CC14 is heated with
aluminium iodide. It crystallizes from ether in dark-red, regular octahedra.
On exposure to air it decomposes into CO2 and I, a change which is accelerated
by heat.
Nitro-derivatives of Orthocarbonic Acid.
Nitrochloroform, Chloropicrin, C(N02)C13, b.p. 112°, D0= 1*692, is
frequently produced in the action of nitric acid on chlorinated
carbon compounds such as chloral, and also when chlorine or bleaching
powder acts on nitro-derivatives, picric acid and nitromethane ;
also from mercury fulminate (p. 249).
In the preparation of chloropicrin, 10 parts of bleaching powder are mixed
L to a thick paste with water. To this is added I part of picric acid or [2,4,6]-
1 trinitrophenol, C6H2[i]OH[2,4,6,](NO2)s.
Chloropicrin is a colourless liquid, possessing a very penetrating
' odour that attacks the eyes powerfully. It explodes when heated
rapidly. When treated with acetic acid and iron filings it is converted
( into methylamine :
CCl,(NO2)+6Ha=CH8.NH2+3HCl+2HtO.
Alkali sulphites change it to formyl trisulphonic acid, ammonia
)- to guanidine, and sodium ethoxide to orthocarbonic ester (p. 428).
I Bromopicrin, CBr8(NO2), m.p. 10°, can be distilled under greatly reduced
'' pressure without decomposition, and is formed, like the preceding chloro-com-
J' pound, by heating picric acid with calcium hypobromite (calcium hydroxide
and bromine), or by heating nitromethane with bromine (p. 151). It closely
resembles chloropicrin.
Bromonitroform, tetranitromethane and the salts of the nitroforms, which
belong here, have already been described among the nitro-paramns (p. 155, sec
alsop, 339).
430 ORGANIC CHEMISTRY
CHLORIDES OF CARBONIC ACID
Two series of salts, two series of esters, and two chlorides can be
obtained theoretically from a dibasic acid :
co<°» co<°£*H' co<ggjg; co<g1H
Ethyl Carbonic Acid, Carbonic Acid, Chlorocarbonic Ester, Phosgene.
only known as salt. Diethyl Ester. only known as ester.
(1) Chlorocarbonic Ester.— The primary chloride of carbonic acid,
chlorocarbonic acid, is not known, because it loses HC1 too easily.
Its esters are, however, known, and are produced when alcohols act
on phosgene or carbon oxychloride, the secondary chloride of carbonic
acid (Dumas, 1833). They are often called chloroformic esters,
because they can be regarded as esters of the chlorine substitution
products of formic acid :
COCla+C2H6OH=ClCOOC2H6+HCl.
They are most readily prepared by introducing the alcohol into liquid and
strongly cooled phosgene (B. 18, 1177). They are volatile, disagreeable-smelling
liquids, decomposable by water, and when heated with anhydrous alcohols they
yield the neutral carbonic esters ; with ammonia they yield urethanes (p. 435) ;
with hydrazine, hydrazicarbonic esters (p. 446) ; with ammonium hydrazide,
nitrogen compounds of carbonic esters (see below). They contain the group
COC1, just as in acetyl chloride ; hence they behave like fatty acid chlorides.
The methyl ester, C1.CO,CH8, b.p. 71-4°; ethyl ester, b.p. 93°; D16 = i'i4396;
propyl ester, b.p. 115°; isobutyl ester, b.p. 128-8°; isoamyl ester, b.p. 154° (B.
13, 2417 ; 25, 1449) ; allyl ester, b.p. 180° (A. 302, 262).
Perchlorocarbonic Ethyl Ester, C1.COOC2C15, m.p. 26°, b.p. 83°, b.p.760 209°,
D = 1-737, is isomeric with perchloracetic methyl ester (p. 288 ; A. 273, 56).
Chlorocarbonate of Glycollic Ester, C1.CO.CCH2CO2C2H6, b.p. 182°. Chloro-
carbonate of Lactic Ester, CH3CH(OCOC1).CO2C2H8, b.p.19 91° (A. 302, 262).
(2) Carbonyl Chloride, Phosgene Gas, Carbon Oxychloride, COC12,
b.p. 8°, was first obtained by Davy, in 1812, by the direct union of CO
with C12 in sunlight ; hence the name phosgene, from </>ws, light, and
y«Wo>, to produce. It is also formed by conducting CO into boiling
SbCl6, and by oxidizing chloroform by air in the sunlight or with
chromic acid :
2CHCl3+CrO34-2O=2COCl2+H20+CrO2Cl2.
Phosgene is most conveniently prepared from carbon tetrachloride
(100 c.c.), and 80 per cent. " Oleum " (120 c.c.), a sulphuric acid
containing SO3 (B. 26, 1990), when the S03 is converted into pyro-
sulphuryl chloride, S205C12.
Technically it is made by conducting CO and C12 over pulverized and cooled
bone charcoal (Paterno).
Carbonyl chloride is a colourless gas, which on cooling is condensed
to a liquid. Reactions : (i) Water at once breaks it up into CO2 and
2HC1. (2) Alcohols convert it into chlorocarbonic and carbonic esters.
(3) With ammonium chloride it forms urea chloride. (4) Urea is pro-
duced when ammonia acts on it. Phosgene has been employed
in numerous nucleus-synthetic reactions, e.g. it has been used
SULPHUR DERIVATIVES OF ORDINARY CARBONIC ACID 431
technically for the preparation of di- and tri-phenylme thane dye-
stuffs (see Tetramethyl Diamidobenzophenone, Vol. II.).
Carbonyl Bromide, COBra, b.p. 64-65°, D16=2'45, is prepared from carbon
tetrabromide and concentrated sulphuric acid, at 150-160°. It is a colourless
liquid which fumes in the air (A. 345, 334).
SULPHUR DERIVATIVES OF ORDINARY CARBONIC ACID
By supposing the oxygen in the formula CO(OH)2 to be replaced
by sulphur, there result :
- Thiocarbonic Acid „ pc^OH Sulphocarbonic Acid
Carbonmonothiolic Acid. z' ^° X)H Thion-carbonic Acid.
Dithiocarbonic Acid PQ^-SH Sulphothiocarbonic Acid
Carbondithiolic Acid *'*"a^OH Thion-carbon-thiolic Acid.
5. CS<|3 Trithiocarbcnic Acid.
The doubly-linked 5 is indicated in the name by sulph or ihion,
whilst it is termed thio or thiol when sirgly linked.
The free acids are not known, or are very unstable, but numerous
derivatives, such as salts, esters and amides, are known. Carbon
oxy sulphide, COS, is the anhydride or sulphanhydride corresponding
with thiocarbonic acid, sulphocarbonic acid and dithiocarbonic acid.
Carbon Bisulphide, CS2, sustains the same relation to sulphothio-
carbonic acid and trithiocarbonic acid that carbon dioxide does to
ordinary carbonic acid.
Phosgene corresponds with thio phosgene, CSC12.
The two anhydrides, COS and CS2, will first be discussed, then the
salts and esters of the five acids just mentioned, to which thiophosgene
and the sulphur derivatives of the chlorocarbonic esters are connected.
Carbon Oxysulphide, COS (1867 C. v. Than, A. Spl. 5, 245), occurs in
some mineral springs as, for example, in the sulphur waters of Hark any and
Parad in Hungary, and is formed (i) by conducting sulphur vapour and carbon
• monoxide through red-hot tubes; (2) on heating CSa with SO3 ; (3) by the
action of COCla on CdS at 260-280° (B. 24, 2971) ; (4) by the action of fatty
acids (p. 276) ; or (5) sulphuric acid, diluted with an equal volume of water on
potassium thiocyanate, HSNC+H2O=COS+NH3 (B. 20, 550).
In order to obtain it pure (B. 36, 1008) the gas may be conducted into an
alcoholic potassium hydroxide solution, and (6) the separated potassium ethyl
thiocarbonate, C2H5OCOSK, decomposed with dilute hydrochloric acid.
Carbon oxysulphide is a colourless gas, with a faint and peculiar odour.
It inflames readily, and forms an explosive mixture with air. It is soluble in
an equal volume of water, and in 6 volumes of toluene at 14°. It is decomposed
by the alkalis according to the following equation :
COS+4KOH=K2CO,+KaS-f2H8O.
Carbon Bisulphide, CS2, b.p. 47°, D0 1*297, was ^^ obtained in
1796 by Lampadius, when he distilled pyrites with carbon. It is pre-
pared by conducting sulphur vapour over ignited charcoal, and is one
of the few carbon compounds which can be prepared by the direct
union of carbon with other elements. It is a colourless liquid with
strong refractive power. It is obtained pure by distilling the com-
mercial product over mercury or mercuric chloride ; its odour is then
432 ORGANIC CHEMISTRY
very faint. It is almost insoluble in water, but mixes with alcohol
and ether. It serves as an excellent solvent for iodine, sulphur, phos-
phorus, fatty oils and resins, and is used in the vulcanization of rubber.
In the cold it combines with water, yielding the hydrate 2CS2-fH2O,
which decomposes again at —3°.
Small quantities of carbon disulphide are detected by conversion into
potassium xanthate, by means of alcoholic potassium hydroxide, from which the
copper salt is obtained. The production of the bright-red compound of CSa
with triethyl phosphine (p. 173, and B. 13, 1732) is a more delicate test. Comp.
also the mustard-oil reaction, p. 63.
HaS and CSa conducted over heated copper yield methane (p. 71). Carbon
disulphide is fairly stable towards dry halogens, so that it is frequently used
as a solvent in adding halogens to unsaturated carbon compounds.
However, moist chlorine gas converts CS2 into thiocarbonyl chloride, CSC12,
and in the presence of iodine into CC13SC1, perchloromethyl mercaptan and
SaCl2 ; finally into CC14 (p. 429). Alcoholates change it into xanthates.
TMocarbonic Acids. — The salts and esters of all these acids,
which when free are exceedingly unstable, may be produced (i) by
the union of the anhydrides, CO2, COS, CS2, with (a) the sulphides
of the alkali and alkali earth metals, (6) the mercaptides of the alkali
metals, (c) and of the last two with alcoholates ; (2) by the trans-
position of the salts thus obtained with alkylogens and alkylene di-
halides ; (3) by the action of alcohols and alcoholates, mercaptans
and alkali mercaptides on COC12, C1.C02C2H6 (p. 430), CSC12 and
C1.CS2C2H5 (p. 434).
Monothiocarbonic Acids.
1. Ethyl Thiocarbonic Acid, Ethyl Carbon-monothiolic Acid, HS.CO.OCaH6.
The potassium salt (Bender's salt), KS.COOC2H5, is obtained (i) from ethyl
xanthic esters and alcoholic potassium hydroxide (p. 433), and (2) from carbon
oxysulphide and alcoholic potassium hydroxide (J. pr. Ch. [2] 73, 242). It
forms prisms, easily soluble in water and alcohol, and produces a white pre-
cipitate with copper sulphate. With ethyl iodide its salt forms Thio-ethyl
Carbonic Ethyl Ester, CaH6S.COOC2H8, b.p. 156°, which can also be prepared from
chlorocarbonic ester, ClCOOCaH6, and sodium or zinc mercaptide. Alkalis decom-
pose it into carbonate, alcohol and mercaptan (B. 19, 1227). Thiodicarbonic
Ester, S(COOCaH5)2, b.p.fa 118°, is produced from chlorocarbonic ester and NaaS
(J. pr. Ch. [2] 71, 278).
2. Sulphocarbonic Acid, Thion-carbonic Acid, HOCSOH. Its ethyl ester,
CS(O.CaH5)a, b.p. 161°, is produced by the action of sodium alcoholate on
thiocarbonyl chloride, CSCla, and in the distillation of S2(CSOC2H8). It is an
ethereal smelling liquid. With alcoholic ammonia the ester decomposes into
alcohol and ammonium thiocyanate, CN.S.NH4.
Dithiocarbonic Acids.
3. Dithiocarbonic Acid, Carbon-dithiolic Acid, CO(SH)2. The free
acid is not known.
The methyl ester, CO(S.CH8)2, b.p. 169° ; ethyl ester, CO(S.CaH5)2, b.p. 196°.
These result (i) when COC12 acts on the mercaptides :
COC12+2C2H5.SK=CO(S.C2H5),+2KC1;
and (2) when thiocyanic esters (p. 468) are heated with concentrated sulphuric
aCN.S,CHg+3H20=CO(S.CH3)2+COa+2NHs.
DITHIOCARBONIC ACIDS 433
(3) from imido-dithio-carbonic ester (p. 450) and dilute hydrochloric acid (C.
1905, I. 447) :
RN:C(SCH3)2 +H2O =OC(SCH3)a + RNHa.
They are liquids with an odour of garlic. Alcoholic ammonia decomposes
them into urea and mercaptans :
/S— CHa
Dithiocarbonic Ethylene Ester, CO<^ , m.p. 310°, is produced from
XS— CHa
trithiocarbonic ethylene ester.
4. Sulphothiocarbonic Acid, Thion-carbon-thiolic Acid, HO.CS.SH,
does not exist free. The xanthates, R.O.C.SSMe, discovered by Zeise
in 1824, are obtained from it.
The xanthates are produced by the interaction of CS2 and alkali
hydroxides in alcoholic solution — e.g. potassium xanthate, consisting
of yellow, silky needles, which crystallize :
CSt+KOH+CaH6.OH=C8H6OCSSK+HaO.
Potassium Ethyl Xanthate.
Cupric salts precipitate yellow copper salts from solutions of the
alkali xanthates together with disulphides S2(CSOR)2 (comp. B. 38,
2184 ; C. 1908, I. 1092). The acid owes its name, gavOo?, yellow,
to this characteristic. By the action of alkyl iodides on the salts
the esters are formed.
The latter are liquids possessing an odour of garlic, and are not
soluble in water. Ammonia decomposes them into mercaptans and
esters of sulphocarbamic acid (p. 448) :
CaH,OCS.SC2H6+NH,=CaH,OCS.NHa+C2H8SH.
Alkali alcoholates cause the production of mercaptan and alcohol,
and salts of the alkyl thiocarbonic acids (p. 432) (B. 13, 530) :
Ethyl Xanthic Acid, C2H5OCSSH, is a heavy liquid, not soluble in water.
[t decomposes at 25° into alcohol and CSa.
Sulphocarboxethyl Disulphide, (S.CS.O.CaHB)2, m.p. 28°, is produced on
idding a solution of iodine or copper salts to potassium xanthate (see above,
md p. 274, for the formation of acetyl disulphide and the disulphides from the
;arbithionic acids).
Ethyl Xanthate Ethyl Ester, C2H6.O.CS.S.CaH5, b.p. 200°, is a colourless oil.
Methyl Xanthic Ethyl Ester, CH3OCSSC2HB (C. 1906, II. 502), b.p. 184°, and
Ithyl Xanthic Methyl Ester, C2HB.O.CS.S.CH8, b.p. 184°, are distinguished by
heir behaviour towards ammonia and sodium alcoholate (see above).
Ethylene Xanthic Ester, C2H4(SCSOC2HB)2, is decomposed by alkalis into the
yclic trithiocarbonic ethylene ester (p. 434) and Bender's salt (p. 432) (B. 38,
88). Ethyl Xanthic Formic Ester, CaHBOCS(SCOOCaHB), b.p. 133°, and Ethyl
Xanthic Acetic Acid, CaH8OCS(SCH2COOH), m.p. 58°, are formed from a xanthate
nd chloroformic ester and chloroacetic ester respectively (J. pr. Ch. [2] 71, 264).
5. Trithiocarbonic Acid, CS(SH)2, is precipitated by hydrochloric acid as
reddish-brown, oily liquid, from solutions of its alkali salts, which are the
roducts of interaction between carbon disulphide and alkali sulphide. It is
isoluble in water and is very unstable. CS2 and alkaline solutions of copper
' 5rm well crystallizable double salts, CS8CuK, CS3Cu(NH4) (B. 35, 1146). Other
ilts, such as CS,.Ba, see C. 1907, I. 539 ; J. pr. Ch. [2] 73, 245.
VOt. I. 3 F
434 ORGANIC CHEMISTRY
The alkali salts of the trithiocarbonic acids, reacting with the corresponding
halogen compound, give rise to the following esters :
Trithiocarbonic Methyl Ester, CS(SCH,)2, b.p. 204-205°.
Trithiocarbonic Ethyl Ester, CS(SCaH6)2, b.p. 240°, with decomposition.
ySCH,
Trithiocarbonic Ethylene Ester, CS I , m.p. 39 '5°. is converted by
oxidation with dilute nitric acid into Dithiocarbonic Ethylene Ester (p. 433)
(A. 126, 269).
Trithiocarboxylic Diglycollic Acid, SC(SCHaCOOH)a, m.p. 172°, is formed
from potassium trithiocarbonate and chloracetic acid. Oxidation converts it
into Carbonyl Dithioacetic Acid, OC(SCHaCOOH)a, m.p. 156° (J. pr. Ch. [2]
71, 287).
Chlorides of the Sulphocarbonie Acids : Thiophosgene, Thiocarbonyl Chloride,
CSC12, b.p. 73°, D = i'5o8, is produced when chlorine acts on carbon disulphide,
and when the latter is heated with PC16 in closed tubes to 200° : «,
It is most readily obtained by reducing perchloromethyl mercaptan, CSC14
(below), with stannous chloride, or tin and hydrochloric acid (B. 20, 2380 ;
21, 102) :
CSCl4+SnCla=CSCla-j-SnCl4.
This is the method employed for its production in large quantities.
It is a pungent, red-coloured liquid, insoluble in water. On standing exposed
to sunlight it is converted into a polymeric, crystalline compound, C2S2C14
=C1.CS.S.CC13> methyl per chlorodithio formate, m.p. 116°, which at 180° reverts
to the liquid body (B. 26, R. 600). Water decomposes thiophosgene into COa
H2S and 2HC1, whilst ammonia converts it into ammonium thiocyanate (p. 467).
Thiocarbonyl chloride converts secondary amines (i molecule) into dialkyl
sulphocarbamic chlorides :
CSCla+NH(C2H6)C6Hft=Cl.CSN<^^*+HCl.
A second molecule of the amine produces tetra-alkylic thioureas (B. 21, 102).
Phosgene and thiophosgene, when acted on by alcohols and mercaptans,
yield sulphur derivatives of chlorocarbonic ester.
Chlorocarbon-thiolic Ethyl Ester .... C1.COSC2H5
Chlorothioncarbonic Ethyl Ester .... C1.CSOC2H5
Chlorodithiocarbonic Ethyl Ester .... Cl.CSSCaH6, b.p.10 90° (B. 36, 3377
Perchlorodithiocarbonic Methyl Ester . . C1.CSSCC1, (see above, thiophosgene
SULPHUR DERIVATIVES OF ORTHOCARBONIC ACID
Perchloromethyl Mercaptan, CC13.SC1, b.p. 147°, results from the action oi
chlorine on CS2. It is a bright yellow liquid. Stannous chloride reduces it
to thiophosgene. Nitric acid oxidizes it to
Trichloromethyl Sulphonic Chloride, CC13.SO2C1, m.p. 135°, b.p. 170°, which
can also be made by the action of moist chlorine on CS2. It is insoluble in
water, but dissolves readily in alcohol and ether. Its odour is like that oJ
camphor, and excites tears. Water changes the chloride to
Trichloromeihyl Sulphonic Acid, CC13.SO3H+H2O, consisting of deliquescenl
crystals. By reduction it yields CHC12.SO3H, dichloromethyl sulphonic acid,
CHaCl.SO3H, monochloromethyl sulphonic acid, and CH,.SO3H (p. 146).
Dibromomethane Diethyl Sulphone, CBr2(SO2C2H5)2, m.p. 131°, and diethyl
sulphone duodomethane, CI2(SO2C2H5)2, m.p. 176°, are formed when bromin
acts on the potassium salt of methane, diethylsulphone, and iodine «
potassium iodide, or iodine alone (B. 30, 487).
Potassium Di-iodomeihane Disulphonate, CI2(SO3K)a, and Potassium lodo
methane Disulphonate, CHI(SO3K)2, are produced when potassium diazomethan.
mlphonate is decomposed with iodine and with hydrogen iodide. Sodiun
amalgam reduces both bodies to methylene disulphonic acid (p 210)
Potassium Methanol Trisulphonate, HO.C(SO3K)3.H2O, results when th>
AMIDE DERIVATIVES OF CARBONIC ACID 435
addition product of acid potassium sulphite and potassium diazomethane disul-
phonate is boiled with hydrochloric acid. A similar treatment of potassium
sulph-hydrazimethylene trisulphonate will also yield it (B. 29, 2161).
AMIDE DERIVATIVES OF CARBONIC ACID
Carbonic acid forms amides which are perfectly analogous to those
of a dibasic acid — e.g. oxalic acid (p. 480) :
co<™«
Carbamic Acid.
CO<NH2 co<NH* ro^NH«
JX)C2H5 C0^C1 CO%Ha
Urethane, Urea Chloride, Urea,
Carbamic Ester. Carbaraic Chloride. Carbamide.
CONH,
COOH
Oxamic Acid.
CONH2
CO.O.C2H5
Oxamethane,
Oxamic Ester.
CO.NH,
CO.NH2
Oxamide.
Carbamic Acid, Amidoformic Acid, H2N.COOH, is not known in a
free state. Its ammonium salt is contained in commercial ammonium
carbonate, when this is prepared by the direct union of two molecules
of ammonia with one of car ban dioxide. It is a white mass which
breaks up at 60° into 2NH3 and CO2, which combine again upon cooling.
By the absorption of water it changes into ammonium carbonate.
When ammonium carbamate is heated to 130-140° in sealed tubes,
water is withdrawn and urea, CO(NH2)2> formed. For other salts
of carbamic acid, see J. pr. Ch. [2] 16, 180.
The esters of carbamic acid are called urethanes ; these are obtained
(i) by the action of ammonia at ordinary temperatures on carbonic
esters :
C2H6O.CO.OC2H6+NH3=CtH5O.CO.NHa+C2H6OH;
and (2) in the same manner from the esters of chlorocarbonic and
cyano carbonic acids :
CaH6OCO.Cl+2NH3=C2H6OCO.NH2+NH4Cl,
C2H5OCO.CN-t-2NH8=C2H8OCO.NHa+CN.NH4.
Also (3) by conducting cyanogen chloride into the alcohols :
N;CCl+2CaH6.OH=H2N.COOC2H5+C2H5Cl;
(4) by the direct union of cyanic acid with the alcohols •
NH:CO +C2H5.OH =H2N.COOC2H5.
When an excess of cyanic acid is employed, allophanic esters are also produced
(p. 444) ; and (5) from urea chloride and the alcohols.
The urethanes are crystalline, volatile bodies, soluble in alcohol, ether and
water. Sodium acts on their ethereal solution with the evolution of hydrogen ;
in the case of urethane it is probable that sodium urethane, NHNa.COOC2H5 or
; NH : C(ONa)OCaH, (B. 23, 2785), is produced. Alkalis decompose them into
f 3Oa, ammonia and alcohols. They yield urea when heated with ammonia :
H2NCO.OCaH5+NH3=H2NCO.NHa+C2H6OH.
ji Conversely, on heating urea or its nitrate with alcohols, the urethanes are
j regenerated (C. 1900, II. 997).
Urethane, Carbamic Ethyl Ester, NH2CO2C2H5, m.p. 50°, b.p. 184°, crys-
1K rallizes in plates ; methyl ester, m.p. 50°, b.p. 177° ; propyl ester, m.p. 53°,
436 ORGANIC CHEMISTRY
b.p. 195* Urethane is successfully employed as a soporific; but is surpassed
Acetyl Urethane, CH3CO.NHCO2CaH5, m.p. 78°. b.p.7a 130°, is obtained from
acetyl chloride and urethane. Hydrogen in it can be replaced by sodium. Alkyl
iodides acting on the sodium compound produce alkyl acetyl urethanes (B. 25,
R 640). When heated to 150° with urea, acetyl urethane passes into aceto-
guanamide, or methyl dioxytriazine, and with hydrazine it yields the triazolones
'Chlor- and brom-acetyl Urethane, a-Bromopropionyl Urethane, etc., result from
the action of sodium urethane on halogen fatty acid esters (B. 38, 297).
Aminoformyl Glycollic Ester, NH2Cp.OCH2CO2C2H5, m.p. 61°, and Amino-
fortnyl Lactic Ester, m.p. 65°, are obtained from the corresponding chloro-com-
pounds (p. 430).
The esters of these alkylated carlamic acids are formed, like the
urethanes, by (i) the action of carbonic or (2) chlorocarbonic esters
on amines ; and (3) on heating isocyanic esters (p. 461) with the
alcohols to 100° :
CO:NC2H6+CaH6OH=CaH6NH.COOC2H5.
also (4) by the interaction of the chlorides of alkyl urea and the alco-
hols ; (5) when alcohols act on acid azides (p. 160).
RCON3+C2H6OH=RNHCOOC2H6+Na.
Methyl Carbamic Ethyl Ester, CH8.HNCOOCaH5, b.p. 170° (B. 28, 855; 23,
2785), can also be prepared from sodium urethane iodomethane.
Ethyl Carbamic Ethyl Ester, C2H6HNCOOC2H5, b.p. 175°.
Ethylene Urethane, C2H6OCONHCH2CH2NHCOOC2H6, m.p. 113°, is formed
from ethylene diamine and ClCOaC2H, (B. 24, 2268).
Hydroxyethyl Carbamic Anhydride, OCHaCH2.NHCO, m.p. 90°, is prepared
from brom-ethylamine hydrobromide, and silver or sodium carbonate (B. 30,
2494).
Alkylldene Urethanes and Diurethanes. Hydroxymethyl Urethane, HOCH2.-
NHCO2C2H5, is prepared from glycollic acid azide and alcohol (B. 34, 2795).
Methylene Diurethane, CH2(NHCO2C2H6)2, m.p. 131°, is produced from urethane,
formaldehyde, and a little hydrochloric acid, and when heated with more acid
and acetic anhydride there is formed anhydroformaldehyde urethane, (CH2 :-
NCO2C2H8)2, m.p. 102° (B. 36, 2206).
Ethylidene Diurethane, CH3CH(HNCOOC2H?)2, m.p. 126°, is prepared from
urethane and acetaldehyde ; it crystallizes in shining needles (B. 24, 2268),
Chloral Urethane, CCl8.CH(OH)NHCO,CaH8, m.p. 103°, is formed from
urethane and chloral. Acid anhydrides convert it into Trichlorethylidene Urethane,
CC13.CH : NCOOC2H6, m.p. 143° (B. 27, 1248).
Diurethane Glyoxylic Acid, (C2H6OCONH)2CHCOaH, m.p. 160° ; ethyl
ester, m.p. 143°', is prepared from glyoxylic ester, urethane and hydrochloric acid
(C. 1906, II. 598).
Carbamic Acid derivatives of the Aminocarboxylic Acids and Peptides are of
importance in the identification and synthesis of the latter bodies (p. 391).
(i) Their Ca and Ba salts are obtained from the amino-acids in solutions of
the alkali earths by the passage of COa as more or less soluble crystalline
precipitates :
CH2NH2 CH2.NH.CO
| +Ba(OH)2+C03 >\ |
COOH CO2Ba— O
They readily decompose, reforming the ammo-acid (B. 29, 397 ; C. 1908,
I. 1287).
(2) Esters are prepared from chlorocarbonic esters and alkaline solutions
of amino-acids or their esters.
URETHANE 437
Carboxethyl Glycine, Urethane Acetic Acid, C2H8O.CONHCH2COOH, m.p.
75° ; ethyl ester, m.p. 28°, b.p.ia 126°.
Carbomethoxy Glycine, CH3OCONHCH2CO2H, m.p. 96° ; ethyl ester, b.p.ia
128°. Thionyl chloride converts these acids into unstable chlorides, ROCONH-
CH2COC1, which, on warming, give off chloro-alkyl and are changed into glycine
anhydride :
CH8OCONHCHaCOCl > OCONHCHaCO.
The anhydride, treated with ice-cold barium hydroxide solution, yields the
same compound as is obtained from the barium hydroxide solution of glycine
when treated with CO2. The anhydride on being heated loses CO2 and
polymerizes to glycine anhydride, (NHCHaCO), (B. 39, 857). Leucine Carbonic
Anhydride, OCONHCH(C4Ht)CO, m.p. 49° (B. 41, 1725).
Carboxethyl Alanine, CaH5OCONHCH(CHs)COOH, m.p. 84°; ethyl ester,
b.p.lt 123° (A. 340, 127).
Carboxyethyl Glycyl Glycine Ester, CaH5OCO.NHCHaCONHCH2COOC2H6,
m.p. 87°, is obtained from glycyl glycine ester (p. 392) and C1CO2R ; or from
carboxyethyl glycine chloride (see above) and glycine ester. Hydrolysis liberates
the free, dibasic ^-Glycyl Glycine Carboxylic Acid, m.p. 208°, with decomposition.
The remarkable solubility of this compound points to its being a ring compound
NH— CHa\
of the formula >C=NHC2-COOH. It yields a diethyl ester, m.p.
(HO)tC O/
149*, isomeric with the original carboxethyl glycyl glycine ester, and a stable
Ba salt, which is different from the unstable salt of the true glycyl glycine acid,
prepared from glycyl glycine barium hydroxide and CO, (B. 40, 3235).
Diglycyl Glycine Carboxylic Acid and Triglycyl Glycine Carboxylic Acid behave
similarly (B. 36, 2094).
Nitroso- and Nitro-ur ethanes are of interest, partly on account of their con-
nection with the diazo- bodies (pp. 169, 213), with nitramide and other compounds.
Nitrosocarbamic Methyl Ester, NO.NHCO2CH3, m.p. 61° (A. 302, 251).
Nitrosour ethane, NO.NHCO2CaH6, m.p. 51°, with decomposition, is formed by
reduction of ammonium nitro-urethane with glacial acetic acid and zinc dust
(A. 288, 304). The salts of these esters probably possess the formula HO.N :-
NCO,R (B. 32, 3148 ; 35, 1148).
Methyl Nitrosourethane, ON.N(CH8)COaC2H5, is prepared from methyl
urethane and nitrous acid. It is a liquid, which with alkalis yields diazo-
methane (p. 213) with the intermediate formation of CH3 N: NOK.
Nitrocarbamic Methyl Ester, NO2.NHCO2CH3, m.p. 88° (A. 302, 249). Nitro-
urethane, NO2.NHCOjC2HB, m.p. 64°, results from the action of ethyl nitrate
on a cold solution of urethane in concentrated sulphuric acid. It is easily soluble
in water, very easily in ether and alcohol, but with great difficulty in ligrom.
It shows a strongly acid reaction, whilst its salts are neutral : Ammonium nitro-
urethane, NO2N(NH4)COaCaH5 ; potassium nitrourethane, NO2NK.CO2C2H5
(A. 288, 267). Nitrocarbamic Acid, NOa.NH.CO2H, liberated from its potassium
salt by sulphuric acid at o°, decomposes into COa and Nitramide, NO2NH2, m.p.
72-85°. This is isolated by means of ether. Potassium Nitrocarbamate,
NO2NHCOaK, results when potassium nitrourethane is treated with potassium
hydroxide in methyl alcohol. It crystallizes in fine white needles.
Methyl Nitrourethane, NO2.N(CH3)CO2C2H5, is formed from silver nitro-
urethane and iodomethane ; also from methyl urethane. It is a colourless,
pleasantly-smelling oil. It is decomposed by ammonia into methyl nitramine
(p. 169).
Urea Chlorides, Carbamic Acid Chlorides, are produced by the
interaction of phosgene gas and ammonium chloride at 400° ; by action
of COC12 on the hydrochlorides of the primary amines at 260-270°,
and also on the secondary amines in benzene solution (B. 20, 858 ;
21, R. 293) :
COCla+NH,.HCl=ClCONH,+2HCl.
43g ORGANIC CHEMISTRY
Urea Chloride, Carbamic Acid Chloride, Chlorocarbonic Amide, C1.CONH2,
m p <>o0 b p. 61-62°, when it dissociates into hydrochloric acid and isocyamc
acid, HNCO! The latter partly polymerizes to cyamelide. Urea chloride under-
goes a like change on standing.
Methyl Carbamyl Chloride, C1CONH.CH,, m.p. 90°, b.p. 94°- Ethyl Urea
Chloride, ClCONH.CaH6, b.p. 92°.
These compounds boil apparently without decomposition, yet they suffer
dissociation into hydrochloric acid and isocyanic acid esters, which reunite on
COHCH3-fHCl=Cl.CONH.CH3.
Dimethyl Urea Chloride, C1.CON(CH8)2, b.p. 167° C. (see Tetramethyloxamide).
Diethyl Urea Chloride, C1.CON(C2H6)2, b.p. 190-195°, is obtained from
diethyl oxamic acid by means of PC15.
Reactions. — (i) The urea chlorides are decomposed by water into CO8 and
ammonium chloride. (2) They yield urethanes with alcohols. (3) With amines
they form alkylic ureas :
H1NCOCl+2C2H6.NH2=H2NCONHCaH6+C2H6NHt.HCl.
Nucleus-synthetic reactions : (4) With benzene and phenol ethers in the presence
of A1C1, they yield acid amides :
C1CO.NH2+C6H6 > C.H5CONH1+HC1.
Carbamide, Urea, CO<^H|» m-P- 132-133°, was discovered by v.
Rouelle in urine in 1773, and was first synthesized from ammonium
isocyanate by Wohler in 1828 (Pogg, A. (1825) 3, 177; (1828)
12, 253). This brilliant discovery showed that organic as well
as inorganic compounds, could be built up artificially from their
elements (p. i). It occurs in various animal fluids, chiefly in the
urine of mammals, and can be separated as nitrate from concentrated
urine on the addition of nitric acid. It is present in small quantities
in the urine of birds and reptiles. A full-grown man voids upon an
average about 30 grams of urea daily. The formation of this substance
is due to the decomposition of proteins. It may be prepared arti-
ficially : (i) by evaporating the aqueous solution of ammonium iso-
cyanate, when an atomic transposition occurs (Wohler) :
CO:N.NH4 > CO(NH8)2.
Mixed aqueous solutions of potassium cyanate and ammonium sulphate (in
equivalent quantities) are evaporated ; on cooling, potassium sulphate crystallizes
out and is filtered off, the nitrate being evaporated to dryness, and the urea
extracted by means of hot alcohol. This is also a reversible process. On heating
T^n urea solution for some time to 100°, four to five per cent, of the urea will be
changed to ammonium cyanate (B. 29, R. 829 ; C. 1903, I. 139).
(2) When a solution of carbon monoxide in ammoniacal cuprous chloride
solution is heated, copper is precipitated and urea is formed (C. 1899, I. 422) :
CO+2NH8+CuaCla=CO(NH,)2+2HCl+2Cu.
It is also formed by the methods in general use in the preparation
of acid amides : (3) by the action of ammonia (a) on carbamic
esters or urethanes, (b) on dialkyl or diphenyl carbonic esters (B.
17, 1826), and (c) on chlorocarbonic esters. The bodies mentioned
under b and c first change to carbamic esters :
NHa.C02C2H6 + NHs=NHaCONHa+C2H6OH
CO(OC2H5)a + 2NH3=NH2CONHa+2CaH6OH
CO(OC6H6)a+2NH8=NH8CONHa+2C8H5OH (method of preparation)
ClC02CaH6 +3NH8=NH2CONHa+CaH66H+NH4Cl.
CARBAMIDE 439
(4) By the action of ammonia on phosgene and urea chloride :
COC124-4NH8==CO(NH2)2+2NH4C1
C1CONH2+3NH8=CO(NH2)2+NH4C1.
(5) By heating ammonium carbamate or thiocarbamate to 130-
140°.
The two following methods of formation show the genetic relation
of urea with thiourea, cyanamide and guanidine :
(6) Potassium permanganate oxidizes thiourea to urea. (7) Small
quantities of acids convert cyanamide into urea :
CNNHa+HaO=CO(NH2)2.
(8) Urea is formed when guanidine is boiled with dilute sulphuric
acid or barium hydroxide solution :
NH:C(NH,),+HtO=CO(NH2)a+NHt.
Urea crystallizes in long, rhombic prisms or needles, which have a
cooling taste, like that of potassium nitrate. It can be easily obtained
pure by one recrystallization from amyl alcohol (B. 26, 2443). It
dissolves in one part of cold water and in five parts of alcohol, and it
is almost insoluble in ether. At high temperatures it decomposes
(1) into ammonia, ammelide (p. 473), biuret (p. 445) and cyanuric acid.
(2) When urea is heated above 100° with water, or when boiled with
alkalis or acids, it decomposes into carbon dioxide and ammonia.
The same decomposition occurs in the natural decomposition of urine.
(3) Nitrous acid decomposes urea, in the same manner that it
decomposes all other amides :
CO(NH2)2+N203=C02+2N2+2N20.
(4) An alkali hypobromite decomposes urea into nitrogen, carbon
dioxide and water. If, however, urea is treated with NOCl-solution
in presence of benzaldehyde, the Hofmann transformation takes place
(comp. carboxylic amides, pp. 160, 276), and there results hydrazine
carboxylic acid (p. i) or hydrazine as a benzal derivative :
NH2CONH,+NaC10+C6H5CHO > C6H5CH:N.NHCOOH+NaCl+H2O.
Salts : Urea, like glycocoll, forms crystalline compounds with acids, bases
and salts. Although it is a diamide it combines with but one equivalent of
acid, whereby one only of the amido-groups is neutralized by the acid radical.
Urea Nitrate, CO(NH2)2.HNO3, forms leaf-like crystals, which are not very
soluble in nitric acid. The oxalate, [CO(NH2)2]2(CO2H)2, consists of thin leaflets,
which are soluble in water.
On evaporating a solution containing both urea and sodium chloride, the
compound, CO(NHa)a.NaCl+H2O, separates in shining prisms.
" The extent of the decomposition of proteins in the animal body
is one of the most fundamental questions of physiology." Urea is
by far the most predominant of the nitrogenous decomposition pro-
ducts of proteins in mammalia and batrachia. Its accurate deter-
mination is, therefore, of the utmost importance.
The Kjeldahl-Wilfarth method is the best adapted for the estimation of
nitrogen in the products of the metabolism. The method of Liebig may also be
used for the determination of urea, which consists in titrating in neutral solution
with mercuric nitrate (see B. 39, 705), when a precipitate, consisting of a mixture
44o ORGANIC CHEMISTRY
of double compounds of carbamide and mercuric nitrate separates, together
with the simultaneous liberation of nitric acid. The Knop-Hufner method
consists in decomposing the urea with sodium hypobromite (see above). Pfluger
and his students have critically examined all methods suggested for this purpose
(comp. Arch. f. d. ges. Phys. 21, 248 ; 35, 199 '. 36, 101, etc.).
Alkyl Ureas are produced according to the same reactions which yield urea
(i) when primary or secondary amines act on isocyanic esters or isocyanic
acid:
CO:NH+NH2.C2H6=NH2CONHC2H§
Ethyl Urea.
CO=NC1H5+NH(C1H5)1=N(C2H^)2CONHCtHs.
Alkyl ureas are formed, also, when isocyanic esters are heated with water
— CO2, and amines being produced (p. 462) ; the latter unite with the esters :
H20 CONC2H5
CO=NC2H6 > C02+NHaC2H5 > CO(NHCSH8)2.
(2) They are also obtained by the action of urea chloride and alkyl-urea
chlorides on ammonia, and primary and secondary amines (p. 437), as well as
by the action of phosgene on the latter.
(3) By the action of alkali hydroxides on the ureldes, the urea derivatives
containing acid radicals :
CH,.NHCONH.COCH$+KOH=CH3.NHCONH1+CHaC01K.
Methyl Acetyl Urea. Methyl Urea.
(4) By desulphurizing the alkyl thioureas with an alcoholic silver nitrate
(B. 28, R.
solution
Ureas of this class are perfectly jinalogous to ordinary urea so far as pro-
perties and reactions are concerned. They generally form salts with one equiva-
lent of acid. They are crystalline salts, with the exception of those containing
four alkyl groups. On heating those with one alkyl group, cyanic acid (or cyanuric
acid) and an amine are produced. The higher alkylated members can be distilled
without decomposition. Boiling alkalis convert them all into CO2 and amines :
CH8NH.CONH2+H2O=COI+NH3+NH1.CH,.
Methyl Urea, CH8.NHCONH2> m.p. 102°, results on heating methyl aceto-
urea (from acetamide by the action of bromine and potassium hydroxide) witb
potassium hydroxide.
Ethyl Urea, C2H6.NHCONH2, m.p. 92°.
a-Diethyl Urea, CO(NH.C2H6)2, m.p. 112°, b.p. 263°.
p-Diethyl Urea, (C2HB)2NCONH2, m.p. 70°.
Triethyl Urea, (C2H3)2NCONHC2H6, m.p. 63°, b.p. 223°.
Tetraethyl Urea, b.p. 210-215°, has an odour resembling that of
peppermint.
Tetrapropyl Urea, b.p. 258° (B. 28, R. 155).
Allyl Urea, C3H6NHCONH2, m.p. 85°, is converted by hydrogen bromide
CHj.CH O
into propylene-$-urea (p. 446), >C:NH (B. 22, 2990 ; C. 1898, II. 766).
CHg— NH
Diallyl Urea, Sinapoline, CO(NH.C3HB)2, m.p. 100°, is formed when allyl
isocyanic ester is heated with water, or by heating mustard oil with water and
lead oxide. Diallyl thiourea is first formed, but the lead oxide desulphurizes it
(P- 452).
Carbamido-ethyl Alcohol, HOCH2CH,.NHCONH2, m.p. 95°, is obtained from
hydroxyethylamine isocyanate or 2-amino-ethanol (B. 28, R. 1010).
Cyclic Alkylene Urea Derivative!.
The ureas and aldehydes combine at the ordinary temperature,
with loss of water, to yield the following compounds :
UREI'DES 441
Methylene Urea, CO<^>CH,, consists of white, granular crystals (B. 29,
4751 ; C. 1897, II. 736).
Ethylidene Urea, CO<^>CHCHS, m.p. 154°, is decomposed, by boiling,
into its component parts. When HC1 gas is passed into a mixture of acetont
and urea, there is formed triacetone diurea, (CH3)8C[NHCON:C(CH8)j]a+3H±O,
m.p. 265-268° with decomposition (B. 34, 2185).
Ethylene Urea, CO<XS52» m.p. 131°, isomeric with ethylidene urea, is
?roduced on heating ethyl carbonate with ethylene diamine at 180°.
t is also formed, together with hydantoi'n (p. 442), when parabanic acid or
oxalylurea is electrolytically reduced (B. 34, 3286).
Nitric acid produces ethylene dinitrourea. The union of ethylene diamine
and hydrocyanic acid, however, gives rise to ethylene diurea, NHjCONH.CH,-
CHjNHCONH,.
Trimethylene Urea, CH2<2>CO, m'p< 26o°' is obtained from cthy1
carbonate and trimethylene diamine ; or by the electrolytic reduction of
barbituric acid and related compounds (see Malonyl Urea). Similarly,
the reduction of methyl uracil (p. 416) produces methyl trimethylene urea,
CH»<CH|— NH>CO' m-P- 20I° <B- 33> 3378 ; 34' 3286)-
Very little is known relative to the action of urea on dialdehydes, aldehyde-
ketones, and diketones : Acetylene Diurea, Glycoluril, C3H,N4O2, is obtained
from glyoxal and urea, as well as by the reduction of allantom (B. 19, 2477).
Nitric acid converts it into Dinitroglycoluril, Acetylene Dinitrodiureine, decom-
poses at 217°, and when boiled with water passes into glycolureine, CsHeNjO,,
isomeric with hydantoic acid.
NH.CH.N(N02Kco CO<NH.CHOH
NH.CH.N(NO,ruu' ^U^NH.CHOH
Glycoluril (?). Dinitroglycoluril. Glycolureine.
Consult B. 26, R. 291, for the action of urea on acetyl acetone.
Nitrosoureas are formed when nitrites act on the nitrates or sulphates of
ureas which contain an alkyl group in the amido group :
Nitroso-methyl Urea, NH2.CO.N(NO)CHS. Nitroso-a-diethyl Urea, NH(C2H6)-
CON(NO)C2HB, m.p. 5°, is a yellow oil at the ordinary temperature. The reduc-
tion of these compounds gives rise to the semicarbazides or hydrazine ureas, which
yield alkyl hydrazines (p. 169) when they are decomposed.
Nitrourea, NO2.NHCONH2, is produced when urea nitrate is introduced into
concentrated sulphuric acid. It forms a white, crystalline powder when recrystal-
lized from water. This melts at higher temperatures with decomposition. It
is a strong acid ; its alkali salts are neutral in reaction, and it expels acetic acid
from acetates (A. 288, 281).
Nitro-ethyl Urea, NO2.NHCONH.C2H6, m.p. 130-131°.
DERIVATIVES OF UREA WITH ORGANIC ACID RADICALS: URE1DES
The urea derivatives of the monobasic carboxylic acids are obtained
by the action of acid chlorides or acid anhydrides on urea. By this
procedure, however, it is possible to introduce but one radical. The
compounds are solids ; they decompose when heat is applied to them,
and do not form salts with acids. Alkalis cause them to separate
into their components.
Formyl Urea, NH2CONH.CHO, m.p. 167° (B. 29, 2046).
Acetyl Urea, NH2CONH.COCH8, m.p. 218°, (A 229, 30; C. 1898, II. 181), is
is not very soluble in cold water and alcohol. It forms long, silky needles.
(Consult B. 28, R. 63, for the metal derivatives of formyl and acetyl urea.)
Heat breaks it up into acetamide and isocyanuric acid. Chloracetyl Urea,
442 ORGANIC CHEMISTRY
H2NCONH.COCH2C1, decomposes about 160°. Bromaceiyl Urea, NH2CO-
NH.COCHjBr, dissolves with difficulty in water. When heated with
ammonia it changes to hydantom. The ureides of the dialkyl acetic acids,
such as (CjHJjCHCONHCONHj, m.p. 207°, are also obtained from dialkyl
malonic acid (p. 491) and urea by means of phosphorus chloride, etc. (C. 1903,
' Methyl Acetyl Urea, CH8.NHCONH.COCH,, m.p. 180°, is obtained from
methyl urea upon digesting it with acetic anhydride ; and by the action of bromine
and potassium hydroxide on acetamide (p. 159) :
2CH,CONHa+Bra = CO<»+ 2HBr.
Diacetyl Urea, CO(NH.COCH,),, results when COCla acts on acetamide, and
sublimes in the form of needles without decomposition.
TTreides of Hydroxyacids. — Open and closed chain and ring-
shaped or cyclic ureides are known. This is especially true, of
a-hydroxyacids, like glycollic, lactic, and a-hydroxyisobutyric acids.
As the open-chain ureides are obtained from the closed-chain
members by severing a lactam-union by means of alkalis or alkali
earths:
xNH.CH. /NH.CHj.COjH
C0< | C0<
XNH.CO XNH2
Hydantoin, Hydantoic Acid,
Closed-chain Urelde Open-chain Ureide
of Glycollic Acid. of Glycollic Acid.
Hydantoin, Glycolyl Urea, C3H4O2N2=CO.NH.CH2.CO.NH, m.p.
• 0<y 5 e
216°, possesses the same series of C and N atoms as the glyoxalines or
imidazoles (p. 347), but the ring is less stable than the glyoxaline ring.
It is prepared (i) by reduction, by means of hot hydriodic acid, of
allantoin (q.v.) and alloxan (q.v.), both important oxidation products
of urea. Also, by electrolytic reduction of pardbanic acid (oxalyl urea)
(B. 34, 3286). (2) It is synthetically produced from bromacetyl urea (see
above) by heating it with alcoholic ammonia, whereby it gives up
hydrobromic acid. (3) Also, by the action of urea on dihydroxy-
tartaric acid (A. 254, 258). (4) Finally, by evaporating a solution
of hydantoi'c acid ester (p. 443) with hydrochloric acid (method of
preparation).
Chlorine produces dichlorohydantotn, C3H2C12O2N8, m.p. 121°. Bromine
gives rise to a body which easily changes into" pardbanic acid (see above)
(A. 327, 355; 348, 85). Concentrated nitric acid produces fi-nitrohydantoin,
CO.N(NOa)CHjCO.NH, m.p. 170°, which on being boiled with water evolves
CO2 and is converted into nitro-amido-acetamide (B. 22, R. 58). Only the j8-NH-
group is substituted on nitration. fi-Acetyl Hydantoin, CON(COCHt)CH,CONH,
m.p. 144°, is prepared from hydantoin and acetic anhydride ; it cannot be
nitrated (A 327, 353).
When boiled with barium hydroxide solution hydantoin is converted into
glycoluric acid or hydantoic acid :
CO.NH.CH2.CO.NH-fH10=H1N.CONH.CHa.COOH.
Hydantoic Acid, Glycoluric Acid, NH2CONH.CHaCO2H, was originally obtained
from uric acid derivatives (allantoin, glycouril, hydantoin), but may be
UREIDES 443
synthesized by heating urea with glycocoll to 120°, by boiling it with barium
hydroxide solution (B. 39, 2954), or ^Y digesting glycocoll sulphate with potassium
isocyanate, analogous to urea (p. 438).
Hydantolc acid is very soluble in hot water and alcohol. When heated with
hydriodic acid it yields CO2, NH8 and glycocoll ; ethyl ester, m.p. 135°, is easily
obtained by the addition of potassium cyanate to glycocoll ester hydrochloride
(B. 33, 3418). It is also formed from glycine ester and sodium methane (B. 38,
3°5)-
Hydantoin Homologues. — For nomenclature, comp. the hydantoln formula
(p. 442) and also A. 327, 355. Hydantoin, iodo-alkyls, and alkali give rise to
f-alkyl hydantoins, in which the NH-group between the two CO-groups is
alkylated (see also B. 22, 685 ; 25, R. 327).
Th£ fi-alkyl hydantoins are formed when urea is fused together with mono-
alkylic glycocolls.
I I
c-Melhyl Hydantoin, CONHCH, CONCH,, m.p. 184°, is formed from silver
hydantoin and iodomethane. Nitric acid converts it into (3-Nitro-c-tnethyl
Hydantoin, m.p. 168° (A. 361, 69). c-Ethyl Hydantoin, m.p. 102°.
^-Methyl Hydantoin, CO.N(CH8).CH,.CO.NH, m.p. 157°, was first obtained
from creatinine, and is also formed when sarcosine (p. 387) is heated with urea ;
or by heating the sarcosine with cyanogen chloride (B. 15, 2111).
fi-Ethyl Hydantoin, m.p. 100*, sublimes readily.
The y-Alkyl Hydantoins may be synthesized by heating the cyanhydrins of
the aldehydes and ketones (p. 379) with urea (see a-Phenyl Hydantoin, and B. 21,
2320) :
/CN /CO.NH
R.CHC +H,N.CO.NH, = R.CH< | +NH,.
N3H XNH.CO
a-Alkyl Hydantoin.
o-Lactyl Urea, y-Methyl Hydantoin, CO.NH.CH(CH8)CO.NH-f H2O, m.p. 140-
145° (anhydrous) is formed, together with alanine from aldehyde ammonia by
the action of potassium isocyanide containing potassium cyanide. Also, by
the action of warm hydrochloric acid on a-Lacturamic Ester (a-carbamidopro-
pionate), NH2CONHCH(CH3)CO2C2HB, m.p. 94°, the product of alanine ester
hydrochloride and potassium cyanate. Lactyl urea when boiled with barium
hydroxide solution yields lacturamic acid, m.p. 155°. With 2 molecules of
bromine it is converted into Bromopyruveide, BrCH:CNHCONHCO, m.p. 242°,
which unites with excess of lactyl urea to form Pyruvic Urtide, C,HtN4O6.
y^-Dimethyl Hydantoin, m.p. 221°, and yfi-M ethyl Ethyl Hydantoin, m.p. 85*, is
prepared from N-methyl alanine and N-ethyl alanine respectively, potassium
cyanate, and hydrochloric acid. y-Ethyl Hydantoin, m.p. 118°, is obtained from
a-aminobutyric acid (A. 348, 50). y-Isobutyl Hydantoin, m.p. 210°. Isobutyl
Hydantoic Acid is prepared from leucine, urea, and barium hydroxide solution;
it is employed in the identification of leucine on account of its slight solubility
(p. 389) (B/39, 2953).
a-Isobutyryl Urea, y-Dimethyl Hydantoin, CONH.C(CH?)2CONH, m.p. 175°, is
produced from acetone, hydrocyanic acid, and cyanic acid (A. 164, 264) ; also
from pinacolyl sulphourea (p. 452) and KMnO4, a-Carbimidoisibutyric Acid,
NH2CO.NHC(CH3)2C9OH, m.p. 155-160°; both these substances are ureide?
of a-hydroxyisobutyric acid.
y-Dialkyl Hydantoins, e.g. y-Diethyl Hydantoin, m.p. 165°, can also be prepared
from cyanacetamide, by converting the latter into diethyl cyanacetamide, and
treating this with bromine and alkali solution (Gaz. Chim. ital, 26, I. 197) :
/CONH, xCONH,
(C2H6)2C<( ^(C2H6)aC<(
N:N \N:CO NHCO
Diethyl Cyanacet- Intermediate Diethyl Hydratoln.
amide. product.
444 ORGANIC CHEMISTRY
CH2— NH— CO
£-Lactyl Urea, Hydrouracil, C4H6N2Oa= | I , m.p. 275°, is
CH 2 — CO— NH
361
obtained similarly to diethyl hydantom, by treating succinic diamide with
CHj.CO.NHj
bromine and alkali, through an unstable intermediate product, |
CH2N:CO
It has been obtained by several other methods. It results, together with tri-
methylene urea, from the electrolytic reduction of barbituric acid (malonyl urea),
of dialuric acid (tartronyl urea), and of uramil (aminomalonyl urea) (B. 34,
3286). Further, by heating acrylic acid with urea at 210-220°, and from
J3-aminopropionic acid and cyanic acid (B. 38, 635). ^-Methyl Hydrouracil,
(CHS)C4H,N8O2, m.p. 265°, and ^-Methyl Hydrouracil, m.p. 220°, are similarly
prepared by heating urea with methyl acrylic acid and crotonic acid. 4-Methyl
hydrouracil is also produced from /J-aminobutyric acid and urea, and from
/?-aminobutyric ester and cyanic acid.
Bromine in glacial acetic acid yields fcrowo-derivatives of hydrouracil, which
easily give up HBr, and are converted into uracils (B. 34, 3751, 4129 ; 38, 636).
The uracils or ureides of /?-aldehydo- and keto-carboxylic acids, together
with those of glyoxylic, oxalic, malonic, tartronic, and mesoxalic acids, will be
considered later in connection with uric acid.
DI- and Trl-carboxylamlde Derivatives. Ureides of Carbonic Acid. — Free
dicarbamidic or imidodicarbonic acid and the free tricarbamic acids or nitrogen
tricarboxylic acids are as unstable as free carbaminic acid itself (p. 435) » ^u^
the esters, amides, and nitriles of these acids are known. They sustain the same
relation to carbamic acid that diglycolamidic acid bears to glycocoll :
PTT pr\ TT /CHjCOOH
NHa.CH2COaH NH^tt^u N^CH.COOH
UH3UJ2ti \CH2COOH
Aminoacetic Acid. Iminodiacetic Acid. Nitrilotriacetic Acid.
(NH.COOH)
Carbamic Acid. Dicarbamidic Acid, Tricarbamidic Acid,
Irainodicarboxylic Acid. Nitrilotricarboxylic Acid.
Dicarbamidic Ester, Imidodicarboxylic Ester, NH(C02C2H5)2, m.p.
50°, b.p. 215°, results when C1C02C2H5 acts on 2 molecules of
sodium urethane ; from nitrogen tricarboxylic ester by decomposition
with alkali ; and from carboxethyl isocyanate (p. 463) and alcohol.
The ester yields a sodium sail, NaN(CO2R)2, more readily than
urethane and acetyl urethane (p. 436) (B. 36, 736 ; 39, 686).
Allophanic Acid, NH2CONH.CO2H, is not known in a free state. A
disodium salt of this acid, NHaCON(Na)COaNa, appears to be formed when a
benzene solution of urethane is boiled in the presence of sodium (B. 35, 779). Its
esters are formed (i) when chlorocarboxylic esters (i mol.)act on urea (2 mols.)
(B. 29, R. 589) ; (2) by passing cyanic acid vapours into anhydrous alcohols
(p. 461). At first carbamic acid esters are produced ; these combine with a
second molecule of cyanic acid and yield allophanic esters (B. 22, 1572) :
HNCO+NHa.COaCaHB=NHaCONH.COaCaH8.
From carbamic esters or urethanes (3) by the action of urea chloride (B. 21, 293) ;
(4) carbonyl chloride (B. 19, 2344) or (5) with thionyl chloride (B. 26, 2172) :
2NHjCOaC1H6+SOCl1=NHaCONH.COaC8HI+HCl-f-S01+CtH6Cl.
For the formation of allophanic esters by decomposition of a-hydroxy-acid
azides (see B. 34, 2794). Nitrogen tricarboxylic ester and also carboxyethyl
isocyanate (pp. 445, 463) with ammonia, yield allophanic ester (B. 39, 686).
DERIVATIVES OF IMIDOCARBONIC ACID 445
Allophanic Ethyl Ester, NH2CONHCO2C2H6, m.p. 191° ; propyl ester, m.p.
155° ; amyl ester, m.p. 162°.
The allophanic esters dissolve with difficulty in water, and, when heated,
split up into alcohol, ammonia, and cyanuric acid. The allophanates are obtained
from them by means of the alkalis or barium hydroxide solution. They show
an alkaline reaction and are decomposed by carbon dioxide. On attempting to
free the acid by means of mineral acids, it at once breaks up into CO2 and urea.
Cyanamidocarbonic Acid. Cyanocarbamic Acid, CN.NHCOaH, is the corre-
sponding nitrile acid of allophanic acid. Its salts are formed by the addition
of CO, to salts of cyanamide (A. 331, 270) :
2CN.NHNa+CO,=NC.N:C(ONa)a+CN.NHt.
The esters of this acid result by the action of alcoholic potassium hydroxide
on esters of cyanamidodicarboxylic acid.
Biuret, Allophanamide, NHCONHaCONHa-fHaO, m.p. 190° (anhydrous), is
formed on heating the allophanic esters with ammonia to 1 00°, or urea to
150-160° :
NH2CONHa=NHaCO.NH.CONH,+NH,.
It is readily soluble in alcohol and water, and decomposes, when heated, into
NH, and cyanuric acid. Heated in a current of HC1, biuret decomposes into
NHj,, CO2, cyanuric acid, urea, and guanidine. The aqueous solution, con-
taining KOH, is coloured a violet red by copper sulphate. (The biuret reaction :
C. 1898, I. 375 ; B. 35, 1105 ; A. 352, 73.)
Mononitrobiuret, NHjCO.NH.CO.NH.NOg. m.p. 105° with decomposition,
is converted by hydrochloric acid and zinc dust into Aminobiuret, the hydro-
chloride of which when boiled with water gives urazole (p. 448), and when treated
with sodium nitrite yields Allophanic Acid Azide, NH2CO.NHCON3 (A. 803, 93).
Imidodioximidocarbonic Acid, NHfC^Qjr ) , m.p. 65-70°, is prepared
from Hg(CH,)2 and nitrogen peroxide (C. 1898, II. 1015).
Carbamic Cyanide, Cyanourea, NHaCONH.CN, the half nitrile of biuret, is
formed, like urea, from guanidine, as well as from cyanoguanidine or dicyandi-
amide (p. 457), by the action of barium hydroxide solution; when digested with
mineral acids it yields biuret (B. 8, 708). (See B. 25, 820, for alkyl cyanureas.)
Carbonyl Diurethane, CO(NHCOOCaH,)a, m.p. 107°, is prepared from urethane
(C. 1897, II. 25) and urea by the action of phosgene at 100° ; also from carboxethyl
isocyanate (p. 463) and water.
Carbonyl Diurea, CO(NHCONH2)2, m.p. 231°, is also produced from urethane
(C. 1897, II. 25), and urea with phosgene at 100°. When heated it passes directly
into NHS and cyanuric acid (p. 463) (B. 29, R. 589).
Carbonyl Dimethyl Urea, CO(NHCONH.CH3)a, m.p. 197°, similarly to the
above, yields n-methyl cyanuric acid, on being heated (B. 30, 2616).
Tricarbamidic Ester, Nitrogen Tricarboxylic Ester, N(COOC2H5)3, b.p.ls 147°,
is prepared from sodium urethane or sodium imidodicarboxylic ester and chloro-
carbonic ester. It is a colourless and odourless oil, scarcely soluble in water.
For the action of alkali and of P2O6, see next paragraph.
Cyanimidodicarboxylic Ester, Nitrogen Tricarboxylic Di-ester Nitrile, N:C-N-
(CO2CaH5)2, results from the interaction of sodium cyanamide, CNNHNa, and
chlorocarbonic ester. Alkali decomposes it into a carboxethyl group ; P2O4
causes the liberation of CO2 and 2C2H4, leaving carboxethyl isocyanate (J. pr.
Ch. [2] 16, 146 ; B. 39, 686).
Derivatives of Imidocarbonic Acid, — The pseudo-forms, imido-
carbonic acid and pseudo-urea, correspond with carbamic acid and urea:
NHa.COOH NH:C(OH)2 CO(NHa)s NH:C<Q^a
Carbamic Acid. Imidocarbonic Acid. Urea. >fr-Urea.
These modifications are not known in a free state, but many deriva-
tives may be referred to them.
Imidocarbonic Ester, HN : C(OC2H5)2, b.p.36 62°, is produced by
446 ORGANIC CHEMISTRY
reducing chlorimidocarbonic ester (B. 19, 862, 2650) ; from di-imido-
oxalic ester (p. 486) by the action of alcoholic sodium ethoxide (B. 28,
R. 760), and from cyanogen chloride (p. 465) by the same reagent.
At 200° it breaks down into alcohol and cyanuric ether (B. 28,
2466).
Chlorimidocarbonic Ethyl Ester, C1N:C(OC2H6)2, m.p. 39°, and the methyl
ester, m.p. 20°, are produced in the action of esters of hypochlorous acid (p. 141)
on a concentrated potassium cyanide solution. They are solids, with a peculiar
penetrating odour, and distil with decomposition. Alkalis have little effect
upon them, whilst acids break them up quite easily, forming ammonia, esters of
carbonic acid and nitrogen chloride.
Bromimidocarbonic Ethyl Ester, BrN:C(OCaH5)a, m.p. 43°, results when
bromine acts on imidocarbonic ester (B. 28, 2470).
Ethyl Imidoclilorocarbonic Ester, C2H5N:CC1(OC2H5), b.p. 126°, is
formed by the union of ethyl isocyanide (p. 248) with ethyl hypo-
chlorite (B. 28, R. 760).
Derivatives of ^- °* Iso-Urea.— Methyl Isourea, NH:C<^^Is, m.p. 45°,
b.p.t 82°, and Ethyl Isourea, HN:C(OC2H5)NH2, m.p. 42°, b.p.15 96°, are formed
as hydrochlorides by the action of alcohols on equimolecular quantities of cyana-
mide and hydrochloric acid: NJCNH2 „„ ^ > HN:C(NH2)(OCH3)HC1. The
CHjOrl
hydrochlorides are decomposed when heated in aqueous solution into chloro-
methane and urea. A similar decomposition occurs with the numerous deriva-
tives of these substances. These ^r-urea ethers can also be considered as being
alkoxy-formamidines or aminoformimido-ethers. Chlorocarbonic ester produces
O-methyl allophanic ester, CH,OC(NH2)NCOaC2H5, m.p. 5° ; isocyanic acid,
O-methyl biuret, CH8OC(NH)NCONH2, m.p. 118° ; acetoacetic ester, O-methyl
methyl uracil (p. 416) ; oxalic ester, o-methyl parabanic acid. Hydrochloric
causes these substances to decompose into chloromethane and allophanic ester,
biuret, methyl uracil, and parabanic acid. Acetyl Methyl Isourea, CH,O.C(NH2)-
NCOCH,, m.p. 58° (C. 1904, II. 29 ; B. 38, 2243).
CH2— 0\ CH2— C\
Ethylene 0-Urea, | /C:NH, or | \C.NH2, is produced by
CH8— NH/ CHa— N^
the action of bromethylamine hydrobromide on potassium cyanate. It is an
oil of basic character, which solidifies with difficulty (B. 31, 2832).
Propylene ^r-Urea, C3H8:CON2Ha, results from bromopropylamine hydro-
chloride and potassium cyanate ; as well as from allyl urea, by a molecular
rearrangement induced by hydrobromic acid (B. 22, 2991 ; C. 1898, II. 760).
HYDRAZINE-, AZINE-, AND AZIDO- DERIVATIVES OF CARBONIC ACID
Hydrazine Carboxylic Acid, NH2NHCOOH or NH3NHCOO is precipitated
when CO, is passed into a cold aqueous solution of hydrazine, in the form of a
white powder. It decomposes at 90° into CO2 and the hydrazine salt of hydrazine-
carboxylic acid, NH2NHCO2.N8H6, m.p. 70° (appr.), b.p.2> 75° (appr.). Sodium
Benzalhydrazine Carbonate, C,H,CH:NNHCO2Na, is prepared from urea, NaCIO,
and benzaldehyde (comp. p. 439).
Hydrazine Carboxylic Ethyl Ester, NH2NHCO2C2H6, b.p.18 92°, is produced
from nitro-urethane (p. 437) by reduction with zinc and acetic acid ; also by the
decomposition of nitrogen tricarboxylic ester with hydrazine. Benzalhydrazine
Carboxylic Ester, m.p. 135° (A. 288, 293 ; B. 36, 745 ; 37, 4523 ; C. 1905, I. 1222).
Azidocarbonic Methyl Ester, N8CO2CH3, b.p. 102°, is obtained from chloro-
carbonic methyl ester and ammonium nitrate ; as well as from hydrazine
Carboxylic acid and nitrons acid (J. pr. Ch. [2] 52, 461 ; B. 36, 2057).
Semicarbazide, Carbamic Hydrazide, NHa.NH.CO.NH2, m.p. 96°, is formed
HYDRAZINE, ETC., DERIVATIVES OF CARBONIC ACID 447
(1) by heating urea and hydrazine hydrate to 100° (J. pr. Ch. [2] 52, 465) ;
(2) from hydrazine sulphate and potassium cyanide ; (3) from amidoguanidine
(B. 27, 31, 56); (4) from nitrourea (A. 288, 311). Acetaldehyde Semicarbazone,
NH2CONH.N:CHCH8, m.p. 162°, is prepared from aldehyde ammonia and
Semicarbazide hydrochloride (A. 303, 79). With benzaldehyde it yields Benzol
Semicarbaxide, NHaCONHN=CHC6H6, m.p. 214°. Acetone Semicarbazone,
NHaCONHN:C(CH,)a, m.p. 187°, passes into bisdimethyl azimethylene (p. 228)
(B. 29, 611).
Acetoacttic Ester Carbazone, NH2CONHN:C(CH,)CHaCO2C2H6, m.p. 129°
(A. 283, 1 8), readily passes into a lactazam. Semicarbazide condenses with
benzil to i,2-diphenyl oxytriazine (Vol. II.). Semicarbazide is a reagent for
aldehydes and ketones.
Alkyl Semicarbazides are obtained (i) by reduction of the nitroso-alkyl-ureas
(p. 441) ; (2) from alkyl hydrazines by means of isocyanic acid or its esters,
whereby the secondary NH-group receives the carbamide residue. The alkyl
semicarbazides only react easily with the aldehydes when the hydrazine NH2-
group is free (C. 1901, 1. 1170 ; B. 37, 2318). 2-Methyl Semicarbazide, NHaN(CH3),
CONH2, m.p. 113°. 2,4-Methyl Ethyl Semicarbazide, NHaN(CH8)CONHC,H8, is an
oil. i ,2-Dimethyl Semicarbazide CH3NHN(CH3)CONH2, m.p. 116° (B. 39, 3263).
Carbamidohydrazoacetic Ester, m.p. 122°, and Aminohydantoic Ester, m.p.
70-74°, are prepared from hydrazinoacetic ester (p. 397) and cyanic acid (B. 31,
167). e-Aminohydantoin, m.p. 244°, forms the partial result of the loss of alcohol
to aminohydantoic ester :
NHCH8COaCaH6 NHaNCHaC02CaH5 NH2N.CH4.CO
NHCONH8 CONH2 CO NH.
Carbamidohydrazoacetic Ester. Aminohydantoic Ester. «-Aminohydantoin.
Carbohydrazide, NH2NH.CO.NHNH2, m.p. 152-153°, is obtained from the
carbonic ester and hydrazine hydrate on heating to 100° (J. pr. Ch [2] 52, 469).
Dibenzal Carbohydrazide, CO(NHN=CHC,H6)2, m.p. 198°.
Imidodicarboxylic Hydrazide, NK(CONHNH2), m.p. 200° with decomposition,
is obtained from nitrogen tricarboxylic ester and hydrazine. It is easily decom-
posed into N2H4 and urazole (see below) (B. 36, 744).
Hydrazodicarbonic Ester, Hydrazodicarboxylic Ester, CaH5OCONHNHCOO.C2HBf
m.p. 130°, b.p. with decomposition about 250°, and is prepared from hydrazine
and C1.C02C2H5 (B. 27, 773 ', J- P*- Ch. [2] 52, 476).
Hydrazodicarbonamide, Hydrazoformamide, NH2CO.NHNH.CONH2, m.p. with
decomposition 245°. It is obtained from potassium cyanate and salts of
diamide or hydrazine : NH2NH2. It also results upon heating Semicarbazide
(B. 27, 57), and from Azodicarbonamide (see below) by reduction. It yields the
latter upon oxidation (A. 271, 127 ; B. 26, 405). NaOCl partially decomposes it
into hydrazoic acid, carbon dioxide, and ammonia (J. pr. Ch. [2] 76, 433).
Azodicarboxylic Acid, Azoformic Acid, CO2HN=NCO2H, is prepared from
azodicarboxylic amide and concentrated potassium hydroxide solution, in the
form of yellow needles. Its potassium salt deflagrates at 1 00°. It readily decom-
poses in aqueous solution into CO,, potassium carbonate, diamide, and nitrogen.
It is not possible to obtain from it the still unknown diimide NH=NH. Diethyl
Ester, b.p.13 106°, is prepared from the hydrazo-ester (see above) and nitric acid.
It is an orange-yellow oil.
Azodicarboxylic Amide, Azoformamide, NH2CON=NCONHa, is formed
(i) by the oxidation of hydrazodicarboxylic amide with chromic acid, and (2) from
azodicarboxylic diamidine, NH2C(NH)N:NC(NH)NH2 (p. 458). It is an orange-
red powder.
Carbamic Acid Azide, Azidocarbonic Amide, N3CONH2, m.p. 97°, is prepared
from Semicarbazide and nitrous acid ; and by the combination of hydrazoic
and cyanic acids. Silver nitrate decomposes it into silver cyanate and silver
azide ; when heated with water it is split up into N3H, NH3, and CO2. Hydrogen
sulphide reduces the azide to urea (A. 314, 339). Hydrocyanic acid unites with
it to form urea azocyanide, carbamidocyanotriazene, NH2CONHN:NCN.
Carbodiazide, Carbazide, Nitrogen Carbonyl, CO(N3)2, is produced from
Carbohydrazide and nitrous acid :
CO(NHNH2.HCl)z+2KNOa=CO(N8)2-|-2NaCl-f-4HaO.
448 ORGANIC CHEMISTRY
It forms spear-like, very volatile crystals, of a penetrating and stupefying odour,
recalling that of phosgene (p. 430) and hydrazoic acid. It is explosive. The
aqueous solution decomposes into COa and 2N3H (B. 27, 2684 ; J. pr. Ch. [2] 52,
482).
Cyclic Hydrazine Derivatives of Urea. — Urazole, Hydrazodicarbonimide,
NH.CCX
>NH, m.p. 244°, forms on heating hydrazodicarbonamide to 200°
NH.CCX
(A. 283, 16), or from urea and hydrazine sulphate heated to 120° (B. 27, 409). It
is a strong, monobasic acid. For its alkylation, see C. 1898, I. 38.
NH.CCX
Aminourazole, I }N.NH,, m.p. 270°, is probably the same as diurea
NH.CCK
or bis-hydrazinocarboxyl, which is obtained from hydrazo-dicarbonic ester and
hydrazine hydrate at 100° (B. 46, 2094).
Methenyl Carbohydrazide, CO< ^CH' m'p* l8l°' is Produced on
heating carbohydrazide with orthoformic ester to 100° (J. pr. Ch. [2] 52, 475).
Hydroxylamine Derivatives of Carbonic Acid.— Hydroxyurethane, HO.NH-
OC H
CO2C,H,, or HON:C<OH2 6, is a colourless liquid. It is produced when an
hydroxylamine solution acts on chlorocarbonic ester (B. 27, 1254).
Hydroxyl Urea, Carbamide Oxime, NHaCONH.OH, m.p. 128°, is obtained from
hydroxylamine nitrate and potassium isocyanate, together with a (? stereo-) iso-
meric body Isohydroxyurea, m.p. 70-72° with decomposition, and when heated in
alcoholic solution it changes into the ordinary hydroxyl-urea. Methyl Hydroxyl
Urea, CH,NHCO.NHOH, m.p. 127° with decomposition, and Ethyl Hydroxyl
Urea, m.p. 129* with decomposition, are formed from methyl and ethyl isocyanate
and hydroxylamine (C. 1902, I. 31). Dimethyl-nitroso-hydroxy-urea, (CH3)2NCO.-
N(NO)OH (B. 30, 2356). Aldehyde - derivative of carbamide oxime,
xNCONH,
RCHO| (C. 1908, I. 948) dissolves readily in water and alcohol, but
with difficulty in ether.
SULPHUR-CONTAINING DERIVATIVES OF CARBAMIC ACID AND OF UREA
The following compounds correspond with urethane and urea :
, r<^2 rQ/2 rc/2 ._„ ~/.
SC,T*. '<O.C2H. CS<SC2H5 CS<NH2 or NH:C<SH.
Thiocarbamic Sulphocarbamic Dithiocarbamic Sulphourea or Thiourea
Ester. Ester. Ester.
Many reactions of sulphourea indicate that its constitution is
probably best expressed by a formula analogous to one of the non-
existing pseudo forms of urea (p. 446).
Alkyl and aryl ethers are derived from imidothiocarboxylic acid, NH :C<J?^
and imidodithiocarboxylic acid, NH:C<|J1
orl
Thiolcarbamic Acid, Carbamine-thiolic Acid, CO<2, is not known in the
free state. Its ammonium salt, CO<^3 , is prepared by leading COS into
alcoholic ammonia (A. 285, 173). It is a colourless, crystalline mass, which is
unstable on exposure to the air. When heated to 130° it breaks up into hydrogen
sulphide and urea.
Alkylamines and COS yield alkyl ammonium salts of alkyl carbamine-thiolic
acids, such as ethyl carbamine-thiolic acid, C2H6.NH.CO.SH, and isobutyl carbamine-
thtohc acid, C.H.NH.COSH. The mercury salts of these two acids decompose
SULPHUR-CONTAINING DERIVATIVES 449
when heated into isocyanic esters and dialkyl ureas (comp. p. 462) (A. 359,
202).
Thiol-carbamic Methyl Ester, NH2COSCH, or NHiC^^ , m.p. 95°, and
ethyl ester, m.p. 108°, both result from the action of ammonia (i) on dithio-
carbonic ester (p. 431), (2) on chlorocarbonic thiolic ester; (3) by the passage
of HC1 into a solution of potassium or alkyl thiocyanate (B. 14, 1083) in alcohol,
when sulphocarbamic ester is also formed (J. pr. Ch. [2] 16, 358).
These are crystalline compounds which dissolve with difficulty in water.
Thiol-carbethy lamine Ethyl Ester, C2H6NH.COSCaH6, b.p. 204-208°. It
results from the union of ethyl isocyanate with ethyl mercaptan.
Sulphocarbamic A.ci&,Xanthogenamic Acid, Thiocarbamic Acid, NH2.CSOH, is
known in its alkyl compounds,
The esters of sulphocarbamic acid — thiour ethanes, the xanthogenamides — are
formed when alcoholic ammonia acts on the xanthic esters (p. 433) :
C2H6S.CSOCsH6+NH3=NHa.CSOC2H6+C2H6SH.
The ethyl ester of sulphocarbamic acid, m.p. 38°, as well as the methyl ester,
m.p. 43°, are both slightly soluble in water. Both esters decompose into mer-
captans, cyanic acid and cyanuric acid when heated. Alcoholic alkalis decompose
them into alcohols and thiocyanates.
The alkyl thiocarbamic esters are obtained when the mustard oils axe heated
to no0 with anhydrous alcohols:
CS:N.C2H5+C2H8.OH=C2H6NH.CS.OCaH5.
They are liquids with an odour like that of leeks, boil without decomposition
and break up into alcohols, CO2, H2S, and alkylamines, and can easily be trans-
formed by halogen alkyls into the isomeric thiolcarbamic esters (above) (C. 1899,
II. 618). Ethyl Thiocarbamic Ethyl Ester, C2H5.NHCSOC2H5, m.p. 46°, b.p. 206°.
A llyl Thiocarbamic Ethyl Ester, CSH6.NHCSOC2H5, is prepared from allyl mustard
oil. Acetyl Thiocarbamic Methyl Ester, CH8CO.NHCS(OCH,), m.p. 80°, is pre-
pared from thiocarbamic ester and acetic anhydride ; or from lead thiocyanate,
icetyl chloride, and methyl alcohol. It is converted by iodomethane into the
someric Methyl Acetyl Thiolcarbamate, CH,CO.NHCOSCHS, m.p. 146° (C. 1900, II.
853).
Dithioearbamic Acid, NH2.CSSH or NH=C(SH)2, is obtained as a red oil
upon decomposing its ammonium salt with dilute sulphuric acid. It readily
breaks down into thiocyanic acid, HS.NC, and hydrogen sulphide. Water decom-
poses it into cyanic acid and 2H2S. Its ammonium salt, NH2.CSSNH4, is formed
when alcoholic ammonia acts on carbon disulphide. It consists of yellow
needles or prisms.
Alkyl Dithioearbamic Acids, Dithiocarbalkylaminic Acids. The amino-salts
af these compounds are formed by heating together carbon disulphide and
primary or secondary amines in alcoholic solution :
CSa+2CaH6NHa=C2H6NH.CSSNH3C2H6.
When the amine salts of ethyl dithiocarbamic acid are heated to 110° dialkylated
:hio ureas are formed (p. 453) :
CaH5NHCS.SH.NHaC2H5=C2H6NHCSNHC2H5-r-HaS.
'.i the salts formed with primary amines are heated in aqueous solution with
netallic salts such as AgNO8, FeCl3, or HgCl8, salts of ethyl dithiocarbamic acid
ire precipitated :
AgNO,
CaH6NHCSS(NH8CaH6) > C2H5NHCSSAg4-HNO3.HaNC2H,,
vhich, when boiled with water, yield mustard oil or isothiocyanic ester (p. 469).
The secondary amine salts of dithiocarbamic acid give no mustard oil (B. 8,
07).
Oxidation with iodine changes the mono- and di-alkyl dithiocarbamic acids
ito thiuram disulphides :
I2 SCSNHR
SCSNHR.
VOL. I. 2 G
2RNHCS.SH > I
Ov-^*.
450 ORGANIC CHEMISTRY
These disulphides, when possessing hydrogen atoms available for the reaction,
are decomposed by heat partly into mustard oils, S and H2S, and partly into
dialkyl thioureas, S, and CSa. Sodium alcoholate converts them into salts of the
isomeric isothiuram disulphide. The latter are converted directly into mustard
oil and sulphur by repeated treatment with iodine (B. 35, 817).
SCS(NHR) SC(NR).SMe I, SCNR
I - > I - > I -f-S2+2MeI
SCS(NHR) SC(NR).SMe SCNR
If alkyl or acyl halides are employed instead of iodine, the decomposition results
in mustard oil dialkyl disulphides, or diacyl disulphides (pp. 144, 274) (B. 38,
2259) Tetra-alkyl thiuram disulphides and potassium cyanide yield the yellow
coloured thiuram monosulphide and potassium thiocyanate. These are also
obtained from dithiocarbamic salts with dithiocarbamic acid chlorides (see
below (B. 36, 2275):
SCSN(CH,)a KNC ,CSN(CH,)a ClCSNfCH^ /CSNfCH,),
- > KSNC+S< •< -- S<
SCSN(CH3)a XSNtCH,), \NH2(CH3)a
Dithiourethanes, Dithiocarbamic Esters, are obtained by several methods
(B. 35, 3368 ; C. 1903, I. 139). They are readily prepared (i) from ammonium
dithiocarbamate (below) and iodoalkyls :
CH3I CH8I
NHaCSS.NH4 - ^NH2CSSCH8; (CHs)aNCSaNHa(CH,)a - > (CH3)2NCS2CHS.
It must be noticed, however, that alkylene dihalides, a-halogen ketones, and
a-halogen fatty esters convert the dithiocarbamates easily into cyclic thiazole
derivatives :
/NR— CH, /NH.CCH, /NHCO
SC< | SC< || SC< |
\S -- CH2 XS — CH XS— CH,
(2) from chlorodithiocarbonic esters (p. 434) and amines:
CaH5SCSCl+NH(C3H7)a - > CaH6SCSN(C8H7)t
(3) from thiocyanic esters and H2S:
CaH6SC:N+H2S - > C2H8SCSNHa.
The dithiocarbodialkylamine acid esters are stable, whilst the simpler
derivatives easily decompose into mercaptans and mustard oils or thiocyanic
acid.
Dithiocarbamic Methyl Ester, NH2CS2CH3, m.p. 41° ; ethyl ester, m.p. 42° ;
isopropyl ester, m.p. 97° ; allyl ester, m.p. 32° ; Methyl Dithiocarbamic Methyt
Ester, CH3NHCS2CH3, b.p.20 156°. Dimethyl Dithiocarbamic Methyl Ester,
(CH3)aNCS2CH3, m.p. 47°. Excess of iodo-alkyl converts the dithio- and alky]
dithio-carbamic esters into the hydroiodides of imidodithiocarbonic esters, HN.C-
(SCH3).RN:C(SC2H5)2, which, on hydrolysis, yield dithiocarbonic esters (p. 432).
Acetyl Dithiourethane, CH3CONHCS2R, is produced from acylation of dithio-
urethane, and from mustard oil by means of thioacetic acid (p. 273). They
are converted by sodium alcoholate and iodo-alkyls into Acetyl Imidodithio-
carbonic Ester, CH3CONC(SR)2 (C. 1901, II. 764 ; 1903, I. 446).
Dialkyl Thiocarbamic Acid Chloride, NR2CSC1, is formed from thiophosgene
and amines (B. 36, 2274).
/NH.CHCH,
Cyclic Derivatives of Dithiocarbamic Ml&.—Carbothialdi**, SC<
XS— NH:CHCH,
is obtained by heating ammonium dithiocarbamate with aldehyde ; and
mixing CSa with alcoholic aldehyde-ammonia. It forms large shining crystals
Isomeric with this is Dimethyl Formocarbothialdine, CS2(NCH3)X(CH2)2, whicl
is prepared from CS2 and formaldehyde-methylimide. lodomethane breaks i'
down into Methylimidodithiocarbonic Dimethyl Ester, CH3N;C(SCH3)a (see above.
(C. 1896, II. 478),
THIOUREA 451
/NH— CO
Phodanic acid SC< , ra.p. 169°, with decomposition, is prepared from
\S CH3
ammonium dithiocarbamate with salts or esters of chlor- or thio-acetic acid:
NH2CS.S.CHaCOOH > NH.CS.S.CH2CO ;
the homologous a-halogen fatty acids behave similarly. Mustard oils (p. 469)
and thioacetic acid form w-alkyl rhodanic acids. Rhodanic acid condenses with
aromatic aldehydes, eliminating water and forming dyes: ArCH:(C,SaNOH)
(C. 1903, I. 446 ; II. 836 ; 1906, I. 1436 ; B. 39, 3068).
Thiourea, Sulphourea, Sulphocarbamide, CS<NH*» or NH:C<SH?*'
m.p. 172°, is obtained (as first observed by Reynolds in 1869 — A. 150,
224) by heating ammonium thiocyanate to 170-180° (A. 179, 113),
when a transposition analogous to that occurring in the formation of
urea takes place (p. 438). This synthesis, however, does not proceed
with ease, and is never complete, because at 160-170° sulphourea
is again changed to ammonium thiocyanate :
1 80°
CSN.NH4 > CS(NH,)2.
Sulphourea is also produced by the action of hydrogen sulphide (in
presence of a little ammonia) or ammonium thiocyanate on cyan-
amide (B. 8, 26) :
CNNH2+SH2=CS(NH,)2.
Sulphocarbamide crystallizes in thick, rhombic prisms, which dis-
solve easily in water and alcohol, but with difficulty in ether ; they
possess a bitter taste and have a neutral reaction.
Reactions : (i) When Sulphocarbamide is heated with water to
140° it again becomes ammonium thiocyanate. (2) If boiled with
alkalis, hydrochloric acid or sulphuric acid, it decomposes according
to the equation :
CSN2H4 +2H2O =COa +2NH3 +HaS.
(3) Silver, mercury, or lead oxide and water will convert it, at ordinary
temperatures, into cyanamide, CN2H2 ; and on boiling into dicyandi-
amide (p. 457). (4) KMnO4 changes it, in cold aqueous solution, into
urea. (5) In nitric acid solution, or by means of H2O2 in oxalic acid
solution, salts of a disulphide, NH2.C=(NH)S-S(NH)==C.NH2, not
known in a free state, are produced (B. 24, R. 71). (See B. 25, R. 676,
upon the condensation of thiourea with aldehyde-ammonias.) Sul-
phourea condenses with a-chloraldehydes and a-chloroketones to
amidoihiazoles (Vol. II.). It yields aromatic glyoxaline (Vol. II.)
derivatives when heated with benzoin.
Constitution. — The behaviour of thiourea when oxidized in acid solution, and
certain other reactions, rather support the formula NH:C<gH 2 instead of the
diamide formula (comp. J. pr. Ch. [2] 47, 135). Possibly free thiourea possesses
the symmetrical formula, whilst its salts are derived from the pseudo-form
Thiourea combines with I equivalent of acid to form salts. The nitrate,
'• CSN2H4.HNO3> occurs in large crystals ; hydrochloride, see C. 1902, I. 113. Auric
chloride and platinic chloride throw down red-coloured double chlorides from the
452 ORGANIC CHEMISTRY
concentrated solution. Silver nitrate precipitates CSN2H4.AgNO3 (B. 24, 3956 ;
B. 25, R. 583) For the constitution of these metallic salts see B. 17, 297. For
the compounds of cuprous chloride with i, 2, or 3 molecules of thiourea, to form
" co-ordinated complex salts," see A. 349, 232.
Alkyl Sulphocarbamides, in which the alkyl groups are linked to nitrogen, are
produced —
(1) On heating the mustard oils with primary and secondary amine bases
(A. W. Hofmann, B. 1, 27) :
NH3+CS:N.C2H6=NH2.CS.NHC2H6.
Ethyl Sulphocarbamide.
NH2.C2H6+CS:N.C2H5=NHC2H5CSNHC2H5.
sym. Diethyl Sulphocarbamide.
NH(CaH6)2+CS:N.C2H5=N(C2H5)2CSNHC2H6.
Triethyl Sulphocarbamide.
(2) By heating the amine salts of the alkyl dithiocarbamic acids (B. 1, 25)
(p. 450) :
C2H6NHCS.SNH8C2H6=C2H5NHCSNHC2H6+H2S.
(3) By heating the corresponding aminothiocyanates (B. 24, 2724 ; 26,
2497).
Ethyl Sulphocarbamide, NH2CSNH.C2H5, m.p. 113°, dissolves readily in
water and alcohol.
sym.-Diethyl Sulphocarbamide, CS(NH.C2H6)2, m.p. 77°. Triethyl Thiourea,
m.p. 26°, b.p. 205°. Monomethyl Thiourea, m.p. 119°. sym.-Dimethyl Thiourea,
m.p. 61° (B. 24, 2729 ; 28, R. 424). unsym.-Dimethyl Thiourea, NH2CSN(CH3)2,
m.p. 159° (B. 26, 2505). Propyl Thiourea, see B. 23, 286 ; 26, R. 87.
Allyl Sulphocarbamide, Thiosinamine, NH2CSNH.C3H5, m.p. 74°, is formed
by the union of allyl mustard oil with ammonia (p. 469).
It is readily soluble in water, alcohol, and ether. Allyl cyanamide sinamine and
triallyl melamine are produced on boiling with mercuric oxide or lead hydroxide
(p. 472). Hydrogen bromide changes it to propylene j/f-thiourea (comp. 20, R.
684).
Diallyl Sulphocarbamide, m.p. 49°, is prepared from allyl mustard oil and
allylamine (C. 1898, II. 768).
Reactions of the Alkyl Sulphoureas.
(1) The sulphocarbamides regenerate amines and mustard oils by distillation
with P,O5, or when heated in HCl-gas :
C2H6.NHCSNHC2H6=»C2H5N:C:S+NHaC2H5.
(2) The sulphur in the alkyl sulphocarbamides will be replaced by oxygen if
these compounds are boiled with water and mercuric oxide or lead oxide,
(a) Those that contain two alkyl groups yield the corresponding ureas :
(CaH6NH)aCS+HgO = (CaH4NH)2CO+HgS;
whereas (b) the mono-derivatives pass into alkylic cyanamides (and melamines)
after parting with hydrogen sulphide (pp. 472, 473).
CaHBNHCSNHa=C2H5NHC.:N+H2S.
(3) On digesting the dialkyl sulphocarbamides with mercuric oxide and amines,
sulphur is exchanged for the imid-group and guanidine derivatives appear (p. 455) :
(C2H5NH)2CS+NH2CaH6-r-HgO = (C2H6NH)2C:NC2H5+HgS+H20.
Consult B. 23, 271, upon the constitution of the dialkyl sulphocarbamides.
/NHCHa /NH.CH,
Ethylene Sulphocarbamide, CS<( I or HS.C^ I , m.p. 195°, is
XNHCH2 ^N— CHa
obtained from ethylene diamine and carbon disulphide (B. 5, 242).
/NHC(CH3)a
Pinacolyl Sulphocarbamide, Carbothiacetonine, SC<^ , m.p. 240-
XNHC(CH3)2
243 , is formed by the action of ammonia on carbon disulphide and acetone
(B. 29, R. 669).
ALKYLENE DERIVATIVES OF PSEUDOSULPHOUREA 453
Derivatives of Pseudosulphocarbamide. — In the preceding derivatives —
whether they are derived from the sym.- or unsym.- sulphocarbamide formula or
not — the alkyl groups were in all cases joined to nitrogen, whereas the compounds
about to be described must be considered as derivatives of pseudosulphocarbamide,
The alkyl pseudosulphocarbamides result upon the addition of alkyl iodides to
the thioureas. The alkyl groups contained in them are known to be united with
sulphur because, when they are acted on with ammonia, they are changed to
guanidines and mercaptans. They also easily condense, like the i^r-urea ethers
(p. 446) with ^S-aldo- and /3-keto-carboxylic esters into the cyclic derivatives and
mercaptopyrimidines, which are hydrolyzed into mercaptans and pyrimidines
(B. 11, 492 ; 23, 2195 ; C. 1903, 1. 1308 ; 1905, 1. 1710) :
C2H?OCO
^-Methyl Thiourea Sodium Formyl Methyl Mercapto-
lodide. Acetic Ester. oxypyrimidine.
Alkylene Derivatives of Pseudosulphourea.
Ethylene Pseudothiourea, NH:C<^ I , or NH2C4 | *, m.p. 85°, is
XNH.CH2 ^N— CH2
obtained from bromethylamine hydfobromide and potassium thiocyanate. It
is a base with strong basic properties, and its salts crystallize well (B. 22, 1141,
2984 ; 24, 260).
/S-CH.CH,
Propylene Pseudothiourea, NH2C^ , formed from bromo-
propylamine and potassium thiocyanate, is perfectly similar. It also results
from allyl-thiourea by action of hydrobromic acid (p. 452) :
CHa=CH +HBr CH3.CHBr -HBr CH3CH S,
I > I > I >C— NHr
CH2NH.CSNH, CH2NH.CSNH, CH,— N^
Acetyl Pseudothiourea, NH:C<gQQ* QJJ , m.p. 165°, is obtained from thiourea
by heating it with acetic anhydride ; also from cyanamide (carbodiimide, p. 471)
and thioacetic acid. This second method argues for the compound being a deriva-
tive of pseudosulphocarbamide.
Carboxalkyl Sulphocarbamide, Thio- or tfj-Thio-allophanic Ester, ROOC.-
NHCSNH2 or ROOC.SC(NH)NH2, is produced by the addition of ammonia or
amines to the carboxalkyl thiocarbimides (p. 471) (C. 1901, II. 211), and by the
interaction of chlorocarbonic esters on thiourea (C. 1903, I. 1123). Dithiobiuret,
R2NCS.NR.CSNR2, and ^-Dithiobiuret, R2NC(NR)S.CSNR2 (B. 37, 4317).
Pseudothio- or -sulpho-hydantoin, C3H4N2S (below), is obtained when
chloracetic acid (A. 166, 383 ; B. 31, 137) acts on sulphocarbamide, and was
/NH.CO
formerly thought to be the real thiohydantom, CS<^ | . However, its
formation from cyanamide and thioglycollic acid (p. 376) and its decomposition,
when boiled with barium hydroxide solution, into thioglycollic acid and dicyandi-
amide prove that it is a pseudosulphocarbamide derivative, which contains
the ring occurring in thiazole compounds (B. 12, 1385, 1588). Similar
thiazole derivatives result when monochloracetic acid is replaced by a-bromo-
propionic acid, bromomalei'c acid, and other halogen-carboxylic acids ; also when
unsaturated acids are employed, such as citraconic acid, to react with thiourea
(C. 1897, I. 853). Pseudosulphohydantom crystallizes in long needles, which
decompose at about 200°. When boiled with acids, it loses ammonia and is
changed into mustard oil acetic acid (p. 469). It is closely related to rhodanic
" (p. 45i):
/NHCO /NHCO /NHCO
OC< | SC< HN:C< |
XS— CH, XS— CH2 XS— CHt
Mustard Oil Rhodanic Acid. Thiohydantom.
Acetic Acid.
454 ORGANIC CHEMISTRY
Alkyl Hydroxythioureas are formed by the action of an ethereal solution of
anhydrous hydroxylamine and jS-alkyl hydro x via mines on mustard oil in c-tlu-r.
The monoalkyl hydroxythioim as readily decompose into sulphur and alkyl
ureas (comp. on the contrary phenyl hydroxythiourea (Vol. II.)) ; the dialkyl
hydroxythioureas are stable. Ethyl Hydroxythiourea, C,H,NH.CSNOH, m.p.
109°; sym.-Diethyl Hydroxythiourea, C.HjNH.CS.NC.HjJOH. m.p. 81° (A.
298, 117).
Hydrazine Derivatives of Thloearbonie Add.
Dithiocarbaxine Acid Hydraxine Salt, NH,NH.CS.SNH,.NHt, m.p. 124°, is
formed by the interaction of hydrazine hydrate and CSa (B. 29, R. 233).
a-Carbamyl p-Thiocarbamyl Hydrazine, H,N.CSNH.NHCONHif m.p. 2iS-j-'o°
with decomposition, is formed from thiosemicarbazide hydrochloride and
potassium cyanate (B. 29, 2508). Boiling concentrated hydrochloric acid converts
it into thiouraxole, ^"1^11' m'P* I77°* ^ft-Dithiocarbamyl Hydraxine,
NH,CSNH.NHCSNHt, m.p. 214°, results when a solution of hydrazine sulphate
and ammonia thiocyanate is boiled (B. 26, 2877).
Thiosemicarbazide, NHj.NHCSNHj, m.p. 181°, is formed together with
ofl-dithiocarbamyl hydrazine (see above), when hydrazine sulphate and ammonium
thiocyanate are boiled together in solution. Like semicarbazide (p. 466) it
readily reacts with aldehydes and ketones to form thiosemicarbaxones, RCH:-
NNHCSNH,, R,C:NHNCSNHt. They are particularly suitable for isolating
aldehydes and ketones on account of the insoluble precipitates given with silver
mercury, and copper salts (B. 85, 2049). ^-Methyl Thiosemicarbazide, CH8NH.-
CSNHNH,, m.p. 137°; ^-Dimethyl Thiosemicarbaxide, CHSNH.CSN(CH,)NH,,
m.p. 138°, and 2,^-Methyl Allyl Thiosemicarbaxide, m.p. 57°, are prepared iiom
hydrazine and methyl hydrazine with methyl and ally! mustard oil respect i\vlv.
They combine readily with aldehydes (B. 87, 2320). afi-Dithioca>
Diallylamine, C8HBNH.CSNH.NH.CSNHC8H5 (B. 29, 859). Fortnyl ^Icthyl
Thiosemicarbazide, m.p. 167°, yields, with acetyl chloride methylimidothiobiazoline,
m.p. 245° (B. 27, 622) :
Nil— NH _ NH - N
CH8NHCS CHO CHSN:C— S— CH.
NH— CSv
Dithiouraxole, \ yNH, m.p. about 245° with decomposition, is formed
an heating ajS-dithiocarbamyl hydrazine with hydrochloric acid. The hydrochloride
of imidothiourazole, | >NH, is produced at the same time (B. 28, 949).
NH.C(NHK
Appendix. Potassium Diazomethane Disulphonate, N2C(SO3K),, oran.ee-yellow
needles, is prepared from Potassium Aminomethane Disulphonate, NHaCH(SO3K)a,
the addition product of potassium cyanide and two molecules of potassium
bisulphite, by means of nitrous acid. With iodine it yields potassium di-iodo-
methane disulphonate, I,C(SO8K), ; and is converted by heat into Potassium
A zinomethane Disulphonate, (SO8K)2C:N.N:C(SO8K)2, in the form of colourless
crystals. The action of diazobenzene (Vol. II.) on the potassium bisulphite
compound with potassium diazomethane disulphonate produces Potassium
Methane Disulphonate Phenylhydraxone, C6H5.NHN:C(SO8K)1 and ulitmately
Formaxyl Sulphonic Acid, -&SOJl (B. 29, 2161).
GUANIDINE AND ITS DERIVATIVES
Guanidine is, upon the one hand, very closely related to ortho-
carbonic ester, urea and sulphocarbamide, and, upon the other, to
cyanamide (p. 426), and all are inter-connected by a series of reactions.
GUANIDINE AND ITS DERIVATIVES 455
Guanidine belongs to the amidines, and may be regarded as the amidine
of amidocarbamic acid :
NH2.C<gH« NH2.C<*Hi NH2C<™*«
Urea. Sulphocarbamide. Guanidine.
The pseudo-forms of urea and thiourea —
(Pseudourea). (Pseadosulpbourca).
known in the form of various derivatives, are the amidines of carbonic
and thiocarbonic acids.
Ouanidine, HN:C(NHa)2, was first obtained (4. Strecker, 1861)
by the oxidation of guanine (a substance closely related to uric acid,
and found in guano) with hydrochloric acid and potassium chlorate.
It is found in vetch seeds and in beet-juice (B. 29, 2651). It is also
important as the substance from which creatine is derived. It is
formed synthetically (i) by heating cyanogen iodide and NH3, and
from cyanamide (p. 471) and ammonium chloride in alcoholic solution
at 100° :
NHa.C=N+NH,.HCl = (HaN)aC:NH.HCl.
This is analogous to the formation of formamidine from hydro-
cyanic acid. (2) It is also produced by heating chloropicrin or (3) esters
of orthocarbonic acid, with aqueous ammonia :
(4) It is most readily prepared from the thiocyanate, which is made by pro-
longed heating of ammonium thiocyanate to 180—190°, and the further transposi-
tion of the thiourea that first forms (B. 7, 92) :
2NH4SNC = 2(HaN)aCS = (H2N)2C:NH.CNSH-f H2S.
The crystals of guanidine are very soluble in water and alcohol,
and deliquesce on exposure. Barium hydroxide solution changes it to
urea. Guanidine salts of the fatty acids are converted by heat into
guanamines, which will be described with the cyanuric compounds
(P- 474)-
Salts. — It is a strong base, absorbing CO2 from the air and yielding crystalline
salts with i equivalent of the acids. The nitrate, CN3Hf.HNO8, consists of large
scales, which are sparingly soluble in water ; hydrochloride, CNaH,.HCl,, yields
a platinum double salt, crystallizing in yellow needles ; carbonate, (CN,H6)a.-
H2CO3, consists of quadratic prisms, and reacts alkaline (see C. 1907, I. 153) ;
thiocyanate, CN8H6.HSCN, crystallizes in large leaflets, m.p. 118°. Silver
guanidine, CNaAg2H8+H2O (A. 302, 33).
The alkyl guanidines result (i) on heating cyanamide with the HCl-salts of
the primary amines — e.g. CH8NH2.HC1, forming Methyl Guanidine; (2) by
boiling sym.-dialkyl thioureas (p. 452) with mercuric oxide and ethylamine in
alcoholic solution (B. 2, 601), producing Triethyl Guanidine.
Vice versa, the alkylated guanidines, when heated with CSa, have their imide-
group replaced by sulphur, with formation of thioureas (p. 451).
Acyl Guanidines are formed when guanidine hydrochloride is heated with
acid chlorides under pressure (C. 1903, II. 988).
GnaneYdes of the Hydroxyacids, — The guanidine derivatives corre-
sponding with the ureides of glycoUic acid, bydantoic acid, and
456 ORGANIC CHEMISTRY
hydantoin are known. Creatine and creatinine, important from a
physiological standpoint, belong to this class.
Glycocyamine, Guanidine Acetic Acid, NH ==C<CNHCH QQ H' *s °htained by the
direct union of glycocoll with cyanamide ; or by heating guanidine carbonate
with glycocoll (C. 1905, I. 156) : *
NH2(NH)CNH,+NH2CH2COOH=NH2(NH)CNHCH,COOH+NHS.
It dissolves with difficulty in cold water and rather readily in hot water,
whilst it is insoluble in alcohol and ether. It forms salts with acids and bases.
When heated it becomes carbonized without melting.
/NHCO
Glycocyamidine, Glycolyl Guanidine., NH =C<^ | , bears the same relation
XNHCH.
to glycocyamine as hydantoin to hydantoic acid :
/NH, /NHCO /NH, /NHCO
C0< C0< | NH=-C< NH=C<
NNHCH2CO2H XNHCH, XNHCH2CO2H XNHCH2.
Hydantoic Acid. Hydantoin. Glycocyamine. Glycocyamidine.
It is produced when glycocyamine hydrochloride is heated to 160°.
Creatine, Methyl Glycocyamine, Methyl Guanidine Acetic Acid,
NH:C<^2H8)CH2CQ2H, was first discovered in 1834 bv Chevreul
in meat extract (/cpea?, flesh). Liebig (1847) gave it a thorough in-
vestigation in his classic research entitled " Ueber die Bestandtheile
der Fliissigkeiten des Fleisches " (A. 62, 257). It is found especially
in the fluids of muscles. It may be artificially prepared (/. Volhard,
1869), like glycocyamine, by the union of sarcosine (methyl glycocoll)
with cyanamide :
CN.NH2+NH(CH,).CH2C02H=H,N(NH)C.N(CH,).CH2COOH.
Creatine crystallizes with one molecule of water in glistening
prisms. Heated to 100°, they lose of water. It reacts neutral, and has
a faintly bitter taste. It dissolves rather readily in boiling water, but
with difficulty in alcohol ; and yields crystalline salts with one equi-
valent of acid.
(i) When digested with acids, creatine loses water and becomes changed into
creatinine (see below), and (2) with barium hydroxide solution it is converted
into urea and sarcosine :
Ammonia is liberated at the same time, and jS-methyl hydantoin is formed.
(3) When its aqueous solution is heated with mercuric oxide, creatine yields
oxalic acid and methyl guanidine. (4) With acetic anhydride it yields Diacetyl
Creatine, m.p. 165° (A. 284, 51).
Creatinine, Methyl Glycocyamidine, NH=C<^ I , occurs con-
N(CH3)CH2
stantly in urine (about 0*25 per cent.), and is readily obtained from
creatine by evaporating its aqueous solution, especially when acids
are present. It crystallizes in rhombic prisms, and is much more
soluble than creatine, in water and alcohol. It is a strong base, which
can expel ammonia from ammonium salts and yields well-crystallized
GUANIDINE AND ITS DERIVATIVES 457
salts with acids. Its compound with zinc chloride (C4H7N30)2.ZiiCl2,
is particularly characteristic. Zinc chloride precipitates it from
creatinine solutions as a crystalline powder, dissolving with difficulty
in water.
(i) Bases cause creatinine to absorb water and become creatine again.
(2) Boiled with barium hydroxide solution it decomposes into j8-methyl hydantoin
and ammonia :
,NH CO
xNH-
<m..L —y^\J XJL'XJLJ.— — —— V_/W
I +H,0=CO< 1 +NH8.
N(CH3)— CH, XN(CH3)— CH,
(3) When boiled with mercuric oxide it breaks up like creatine into methyl
guanidine and oxalic acid.
When creatinine is heated with alcoholic ethyl iodide, the ammonium iodide
of ethyl creatinine, C4H7(C2H5)N3O.I, is produced. Silver oxide converts this
into the ammonium base, C4H7(C2H5),N3O.OH.
a-Guanidine Propionic Acid, (N2H3)C.NH.CH(CH3)COOH, m.p. 180°. fi-Guani-
dine Propionic Acid, m.p. 206-213°, with decomposition, when heated with hydro-
chloric acid yields the hydrochloride of fi-alacreatinine, HN:CNHCH2CHaCONH
(C. 1905, 1. 156).
Guaneides of Carbonic Acid. — Guanoline, guanyl urea, biguanide, and pro-
bably dicyandiamide, corresponding with allophanic ester, biuret, and cyanurea,
(P- 455) i are derivatives of the guaneide of carbonic acid. This is not known, and
probably cannot exist :
Allophanic Ester. Biuret. Cyanurea.
NH:C<NHC02C2H, NH:C<NHCONH,
Guanoline. Guanyl Urea.
MW r^NH2 ™.r^NH2
w±i:v>NHC(NH)NH| ^NH.CH.
Biguanide. Dicyandiamide (?).
Guanoline, Guanidocarbonic Ester, NH:C<[xrMrr» r TJ +£H2O, m.p., dehy-
IN XiV./N-' 0^-' O-tl &
drated, 114°. It is obtained from Guanidodicarbonic Diethyl Ester, NH:C-
(NH.CO2C2H5)2, the reaction-product arising from chlorocarbonic ester and
guanidine, through the action of ammonia (B. 7, 1588).
NH
Dicyandiamidine, Guanyl Urea, NH:C<CNHCO NH ' is formed (x) bY the
action of dilute acids on dicyandiamide or cyanamide, or (2) by fusing a
guanidine salt with urea (B. 7, 446), (3) from urea by heating it with benzene
sulphochloride, whereby it is obtained as a benzene sulphonate (C. 1901, I. 885).
It is a strongly basic, crystalline substance. It forms a copper derivative having
a characteristic red colour, and a yellow nickel compound, Me(N4HfOC2)a-f-H2O
(B. 39, 3356). When digested with barium hydroxide solution it decomposes
into CO2> 2NH3, and urea (B. 20, 68).
Biguanide, Guanyl Guanidine, NH:C<NHC(NH)NH • is formed (x) on
heating guanidine hydrochloride to 180-185° ; (2) when cyanoguanidine is
heated with ammonium chloride. It is a strongly alkaline base, forming a copper
derivative with characteristic red colour. Chloroform and alkali hydroxide
convert it into formoguanamine (p. 474).
Dieyandlamide, Par am, Cyanoguanidine, NH:C<£j^ja£N, m.p. 205°, results
from the polymerization of cyanamide upon long standing or by evaporation of
its aqueous solution, and can easily be prepared from technical calcium
458 ORGANIC CHEMISTRY
or sodium cyanamide (p. 471) (C. 1905, II. 153°. etc). Contrary to the
two substances described above, it is a neutral body. Ammonia converts
it into biguanide ; dilute acids into guanyl urea. With piperidine it forms a
biguanide derivative (B. 24, 899 ; 25, 525), with hydrazine hydrochloride when
<.
| , m.p. 206
.. °
NHC:NH
(B. 27, R. 583) ; both reactions form a basis for the ascribed formula.
Thioeyanodiamidine, Guanyl Thiourea, NH2CSNHC(NH)NH2, is obtained from
thiourea and PC16 or thiophosgene. It is isomerized at 100° to guanidine thio-
cyanate. Silver salts produce dicyanodiamide with loss of H2S (comp. B. 36,
3322).
Nitro-, amino-, and Hydroxy-guanidines and their transposition products.
Of these substances, nitroguanidine is the most suitable material for the
preparation of a series of remarkable guanidine and urea derivatives (Thiele,
A. 270, i ; 273, 133 ; B. 26, 2598, 2645).
Nitroguanidine, NH:C<^NO«, m.p. 230°, results on treating guanidine
with a mixture of nitric and sulphuric acids. It dissolves with difficulty in cold
water, more readily in hot water, and particularly freely in alkalis, because of
its feeble acid character.
Nitrosoguanidine, NH:C<^ ° (?), is produced by reducing nitroguanidine
with zinc dust and sulphuric acid. It consists of yellow needles, which explode
at 160-165°.
Aminoguanidine, NH:C<^NH*, results when nitro- and nitrosoguanidine
are reduced with zinc dust and acetic acid, or by electrolysis in neutral solution
with a zinc cathode (C. 1906, I. 1066), and can be precipitated as a slightly soluble
bicarbonate (A. 302, 333). Aminoguanidine decomposes readily when in a pure
condition, and when boiled with acids it breaks down, with the temporary pro-
duction of semicarbazide (p. 446), into carbonic acid, ammonia, and hydrazine,
which can therefore be conveniently prepared in this manner :
NH-C<TNHNH» H2o CO<NHNH* H*° , ro . NH2NH,
^'^NH, — i> ^NHa - > C°2+NH3
Aminoguanidine forms well-crystallized compounds with dextrose, galactose,
and lactose and many other aldehydes and ketones (B. 28, 2613). Glyoxal
and a-diketones with aminoguanidine lose water and form bis-aminoguanidine
(A. 302, 275).
<H— N
|| , m.p. 159°, is formed from formyl amino-
guanidine nitrate and soda (A. 303, 33). See also Guanazole (above).
Axodicarbondiamidine, JJN^^ — ^=N — C<^Njja, is obtained as nitrate when
aminoguanidine nitrate is oxidized with KMnO4. The azonitrate forms a yellow,
sparingly soluble, crystalline powder, which explodes at 180-184°. It passes
into azodicarbonamide (p. 447) when boiled with water.
Hydrazodicarbonamidine, 2>C— NH— NH— C^1, results as nitrate
when azodicarbonamidine nitrate is reduced with H2S.
N\ ^NH
Axidocarbamidine, Carbamide Imidazide, \ >N — C? corresponds with
N/ \NH2»
carbamic acid azide (p. 447). It is only stable in solution, since it very
readily isomerizes into amidotetrazole (see below) : nitrate, (CN6Hs)HNO,f
m.p. 129°, is obtained^ f rom aminoguanidine and potassium nitrite in nitric acid
solution, in the form of colourless crystals. Excess of sodium hydroxide
solution converts it partially into cyanamide and hydr azoic acid. These substarces
NITROGEN DERIVATIVES OF CARBONIC ACIDS 459
unite in aqueous solution probably to reform azidocarbamidine, which is simul-
taneously isomerized to aminotetrazole (A. 314, 339) :
N HN N >>N - N
HaN.C< ||
XNH— N
Cyanamide Hydrazoic Acid. Aminotetrazole.
Diazoguanidine Cy amide, Triazene Dicarboxylic Amide, Amino-imino-methyl
Cyanotriazene, ^C — NH — N=N.CN, is produced from azidocarbamidine
nitrate and potassium cyanide. The amide, obtained from the nitrile, takes up
bisulphite and forms a triazan- or prozan- derivative — Sodium Triazandicarboxylic
Amidine Amidosulphonate, a>C.NH.N<» (A. 305, 64, 80).
N— N^. JS - N
Azotetrazole, \\ >C — N=N — C<f j|f results when amidotetrazole
N— NHX XNH— N
is oxidized by potassium permanganate (A. 303, 57).
Isocyanotetrabromide or Tetrabromoformalazine, Br,C=N — N=CBra, m.p. 42°.
is produced when hydrazotetrazole, the reduction-product of azotetrazole, is
treated with bromine (B. 26, 2645). With alkalis isocyanotetrabromide
apparently yields isocyanoxide, CO=N — N=CO (?), or a polymer of it. Should
an oxidizable body like alcohol be present, isocyanogen, C=N — N=C(?), is pro-
duced. This substance has an odour very much like that of isonitrile. Sodium
tthoxide converts isocyanotetrabromide into Azimethyl Carbonate, (CHSO)2C
=N— N=C(OCH3)8 (A. 303,71).
Diaminoguanidine, HN:C(NHNH2)a, obtained as a hydrochloride or hydro-
bromide by the action of cyanogen chloride or bromide on hydrazine. Dibenzal'
diaminoguanidine, HN:C(NHN:CHCeH6)2, m.p. 180°, exists as yellow needles.
Hydrazine and two molecules of cyanogen bromide form guanazine,
NH— C(NHK
HN:C(NHNH)2C:NH, or I >NNH, (B, 37, 4524 ; C. 1905, II. 122).
NH— C(NH)X
Triaminoguanidine, H2N.N:C(NHNH2)2 ; its hydrochloride is obtained by
heating hydrazine hydrate with carbon tetrachloride in a stream of ammonia.
Tribenzal Triaminoguanidine, CaH6CH:NN:C(NHN:CHC6H5)2, m.p. 196°, is
hydrolyzed into benzaldehyde, hydrazine, and carbohydrazide (p. 447) (B. 37,
3548).
Dihydroxyguanidine, **2NC<-, is obtained as hydrobromide from
cyanogen bromide and hydroxylamine in methyl alcohol. It is stable to acids,
but is changed immediately by alkalis into an unstable red azo body, which becomes
ultimately converted into azoxybismeflienylamidoxime, H2NC(NOH).(N2O)C-
(NOH)NH2, hydrazodicarbonamide, and other substances.
Amino-methyl-nitrosilic Acid, H2NC<j^~H, is produced when alcoholic
potassium hydroxide decomposes the above-mentioned intermediate azo-body.
It consists of very unstable green tabular crystals, and combines to form blue
or green salts ; potassium salt is deposited from alcohol as steel blue brilliant
needles (B. 38, 1445).
NITRILES AND IMIDES OF CARBONIC AND THIOCARBONIC ACIDS
The nitriles, cyanic acid, thiocyanic acid, cyanogen chloride, and
cyanamide, stand in a systematic and genetic connection with carbamic
46o ORGANIC CHEMISTRY
acid, thiocarbamic acid, urea chloride, and urea, as well as with
thiourea :
NH2COOH NHjCOSH NH,COC1 NH2CONHa NH2CSNHt
Carbamic Acid. Thiocarbamic Urea Chloride. Urea. Thiourea.
Acid.
N=C.OH N^C.SH NEECC1 N^C.NH,
Cyanic Acid. Thiocyanic Acid. Cyanogen Chloride. Cyanamide.
The empirical formulae of cyanic acid, HONC, thiocyanic acid,
HSNC, and cyanamide, CN2H2, have each another structural formula :
NH=C=0 NH=CS NH=C=NH
Isocyanic Acid, • Isothiocyanic Acid, Carbodi-imide.
Carbimide. Thiocarbimide.
Indeed, alkyl derivatives are known which correspond with both
formulae of each of these bodies. The isothiocyanic esters, or mustard
oils, may be especially mentioned. The constitution of free cyanic
acid, and of cyanamide, has not yet been determined with certainty,
whilst the normal formula, HS.C=N, is universally attributed to
thiocyanic or sulphocyanic acid. Cyanic acid itself has received the
iso-formula, HN=C=O, because it forms isocyanic esters with diazo-
methane (C. 1906, II. 1723).
The remarkable tendency of cyanic acid and cyanamide to poly-
merization is particularly noteworthy ; the former substance gives rise
to cyamelide and cyanuric acid, and the latter to dicyanodiamide and
tricyanotriamide or melamine.
When the simple derivatives of cyanic acid have been discussed, then the
corresponding trimolecular polymers will be described.
Numerous compounds containing the cyanogen group have been
described and discussed in the preceding pages as nitriles of carboxylic
acids (p. 278), hydroxy- and ketonic acids (pp. 378, 409, 466). The
simplest body, hydrogen cyanide or hydrocyanic acid (p. 239), has been
discussed with formic acid. Cyanic acid bears a relation to hydrocyanic
acid similar to that of carbonic acid to formic acid.
OXYGEN DERIVATIVES OF CYANOGEN, THEIR ISOMERIDES AND
POLYMERIDES
Cyanic Acid, HN:CO or HO:C.N, isomeric with fulminic acid
or carbyloxime (p. 248), is obtained by heating polymeric cyanuric
acid. The vapours which distil over are condensed in a strongly
cooled receiver.
The acid is only stable below o°, and is a mobile, very volatile
liquid, which reacts strongly acid, and smells very much like glacial
acetic acid. It produces blisters upon the skin. At about o°, the
aqueous solution is rapidly converted into carbon dioxide and
ammonia 2
HONC+H2O=CO2+HNt.
At o°, the liquid cyanic acid passes rapidly into the polymeric
cyamelide — a white, porcelain-like mass, which is insoluble in water,
CYANIC ACID 461
and when distilled reverts to cyanic acid. Above o°, the conversion
of liquid cynanic acid into cyamelide and cyanuric acid (C. 1902, 1. 526)
occurs, accompanied by an explosive generation of froth (comp.
formaldehyde, p. 197).
Cyamelide is also obtained by grinding together potassium cyanate
and crystallized oxalic acid, and washing out with water. It is a
loose white powder, only slightly soluble in all solvents. Prolonged
boiling with water decomposes it into NH3, CO2, and partly into
cyanuric acid (p. 463). When digested with concentrated sodium
hydroxide solution it is converted completely into tri-sodium cyanurate.
This probably corresponds with the formula °<c(NH)!o'>c(NH) > li
is therefore analogous to trioxymethylene (p. 199) (B. 38, 1013).
Cyanic acid dissolves in alcohols, yielding esters of allophanic acid
(p. 444).
Potassium Cyanate, Potassium Isocyanate, ordinary cyanate of
potassium, KO.C-N or KN:C:0, is formed in the oxidation of
potassium cyanide in the air, or with some oxidant like lead oxide,
minium, potassium permanganate (B. 36, 1806), or sodium hypo-
chlorite (B. 26, R. 779). It is most conveniently made by heating
small portions (3-5 gm.) of an intimate mixture of 100 parts potassium
ferrocyanide and 75 parts of potassium bichromate in an iron dish,
during which NH3 should not be set free (B. 26, 2438). It results, too,
on conducting dicyanogen or cyanogen chloride into potassium hy-
droxide solution (B. 23, 2201). The salt crystallizes in shining leaflets,
resembling potassium chlorate, or in quadratic plates (B. 27, 837),
and dissolves readily in cold water, but with more difficulty in hot
alcohol. In aqueous solution it decomposes rapidly into ammonia
and potassium carbonate.
Potassium isocyanate precipitates aqueous solutions of the heavy metals.
The lead, silver, and mercurous salts are white, the cupric salt is green in colour.
Lead cyanate is quantitatively hydrolized to carbonate and urea when boiled with
water (C. 1904, I. 160).
Ammonium cyanata, NH4.OC|NorNH4.N:C:O, is a white crystalline powder,
formed by contact of cyanic acid vapours with dry ammonia, or by mixing ethereal
solutions of cyanic acid and ammonia (C. 1900, I. 107). Potassium hydroxide
decomposes it into potassium isocyanate and ammonia. On heating the dry
salt to 60°, or by evaporating its aqueous solution it passes into the isomeric
urea (p. 438). Similarly, cyanurates of primary and secondary amines are
changed into alkylated ureas, whilst those of the tertiary amines remain
unchanged.
The cyanates of the primary and secondary amines are similarly converted
into alkyl ureas, whereas the salts of the tertiary amines remain unchanged.
Esters of Normal Cyanic Acid, Cyanetholiner } RO — C=N, are not
known (A. 287, 310). Imidocarbonic acid ethers (p. 445) are pro-
duced when cyanogen chloride acts on sodium alcoholates in alcoholic
solution.
Esters of Isocyanic Acid, Alkyl CarUmides or Alkyl Cyanates. —
Wilrtz prepared these, in 1848, (i) by distilling potassium ethyl sulphate
with potassium isocyanate :
(CaH8)KSO44-KN:CO=CaH6N:CO + K,SO4.
462 ORGANIC CHEMISTRY
Esters of isocyanuric acid are formed at the same time, in conse-
quence of polymerization. (2) Isocyanic esters are also produced by
oxidizing the carbylamines with mercuric oxide :
C,Hg.NC+O=CaH5.N:CO ;
(3) by the action of silver isocyanate on alkyl iodides at low tem-
peratures (together with esters of cyanuric acid, p. 463) :
C,H5I+AgN:CO=C,H8N:CO-f-AgI ;
and (4) by heating the dry mercuric chloride double salt of the alkyl
carbamine thiolic acids (p. 449) (A. 359, 202) :
C2H6NH.CO.S.HgCl > CaH6N:CO+HgS+HCl.
These esters are volatile liquids, boiling without decomposition,
and possessing a very disagreeable, penetrating odour, which provokes
tears. They dissolve without decomposition in ether. On standing
they pass rather rapidly into the polymeric isocyanuric esters.
Isocyanic Methyl Ester, CH3N:CO, Methyl Isocyanate, Methyl Carbimide,
b.p. 44°-
Isocyanic Ethyl Ester, C2H6N:CO, b.p. 60°.
Isocyanic Allyl Ester, C3H5N.CO, b.p. 82°.
Isocyanic Isobutyl Ester, CONC4H9, b.p. 101°.
Reactions. — In all their reactions they behave like carbimide
derivatives, in which the alkyl group is united to nitrogen, (i) Heated
with KOH they become primary amines and potassium carbonate
(p. 159). This is the method Wtirtz used when he first discovered
them.
(2) Acids in aqueous solution behave similarly :
C1H5N:CO+H20+HC1=C02+C2H6NH2.HC1.
(3) With the amines and ammonia they yield alkyl ureas (q.v.).
(4) Water decomposes them at once into CO2 and dialkyl ureas. In
this decomposition amines form first, CO2 being set free, and these
combine with the excess of isocyanic ester to dialkyl ureas (q.v.).
(5) Fatty acids convert them into alkyl primary acid amides
(p. 275), CO2 being simultaneously evolved. (6) Acid anhydrides
convert them into alkyl secondary acid amides (p. 276).
(7) The esters of isocyanic acid unite with alcohol, yielding esters of carbamic
acid (p. 435).
(8) As derivatives of ammonia the isocyanic esters are capable of combining
directly with the halogen acids. The products are urea chlorides (p. 437), from
which the isocyanic esters are again separated by distillation with lime :
HC1
C8H6NCO < > CtH6.HNCO.Cl.
Ca(OH),
Glycocollic Ester Isocyanate, OC:NCH2CO2C8H6, b.p.16 115-120°, is obtained
from glycocollic ester hydrochloride by excess of phosgene in toluene. Water
converts it into carbiminodiacetic acid, CO(NHCH2CO2H)2, m.p. 167°. Other
amino-acids yield corresponding mixed urea derivatives (C. 1906, II. 671).
Acetyl Isocyanate, OC:N.COCH8, b.p. 80*, is prepared by the action of acetyl
chloride on mercury fulminate (p. 249), and on silver cyanate (B. 36, 3214).
Alcohol and ammonia convert it into acetyl urethane (p. 436) or monoacetyl
urea (p. 441).
CYANURIC ACID AND ITS ALKYLIC DERIVATIVES 463
Methyl Sulphonyl Isocyanate, CH3SO2N:CO, m.p. 31°, b.p.10 73-5-75° (B. 38,
2015).
Carboxyethyl Isocyanate, C2H5OCO.N:CO, b.p. 116°, is produced from nitrogen
tricarboxylic ester (p. 445) by means of P2O5. It unites with alcohol to form
imido-carboxylic ester (p. 444) ; and with ammonia to form allophanic ester
(p. 444). Water converts it to carboxyl diurethane (p. 445) (B. 39, 686).
CYANURIC ACID AND ITS ALKYLIC DERIVATIVES
Just as with cyanic acid, so here with tricyanic acid, two structural
cases are possible :
(i) (HO)C=N C(OH) (2) (HO)C=N C(OH) (3) OC— NH C(OH)
N=C(OH)— N NH— CO— N NH— CO— N
Normal Cyanuric Acid. Intermediate Product.
(4) OC— NH— -^CO
NH— CO— NH
Iso- or Pseudo-cyanuric Acid.
Ordinary solid cyanuric acid, like cyanic acid, is most probably
to be represented by an imide, tricarbimide, or isocyanuric formula
(4) When titrated with sodium hydroxide and phenolphthelein in
aqueous solution, it behaves as a monobasic acid, yielding salts accord-
into to formula (3). Two equivalents of alkali produce dibasic salts,
corresponding with formula (2), which, on boiling, take up a third equi-
valent of the metal, and form stable, well-crystallizing tribasic salts,
C3N3O3Me3 (formula i), some of which are only slightly soluble in water.
Corresponding with these consecutive desmotropic transformations
(p. 38), the temperature coefficient of the electrical conductivity
(taken as of a monobasic acid) of an aqueous solution of cyanuric
acid increases with increasing temperature : the acid becomes stronger
by a change of constitution as from formula 4 to i (B. 39, 139). Its
behaviour as a " pseudo-acid " is shown by the occurrence of isomeric
mercury salts : 0-mercury cyanurate C3N3(OHg)3, obtained from tri-
sodium cyanurate and mercury salts, is decomposed by alkalis ;
N -mercury cyanurate, C3O3(NHg)3 is produced from free cyanuric acid
and mercury salts, and is not decomposed by alkalis (B. 35, 2717).
Esters can be obtained from all four formulae, but only those in
which the alkyl group is united to oxygen can be decomposed by alkalis
(B. 38, 1005). The cyanuric halides (p. 465) are derived from formula i.
Cyanuric Acid, C3N3O3H3, was first observed by Scheele in the
dry distillation of uric acid. It is produced (i) by heating tricyanogen
chloride, C3N3C13, or bromide (B. 16, 2893) with water to 120-130°,
or with alkalis. (2) Dilute acetic acid added to a solution of potas-
sium isocyanate gradually separates primary potassium isocyanate,
C3N3O3H2K, from which mineral acids liberate cyanuric acid. (3) It
is formed, also, (a) on heating urea (b) or carbonyl diurea (p. 448) ;
(c) on conducting chlorine over urea heated to 130-140° ; (d) when
urea is heated with a solution of phosgene in toluene to 100-230°
(B. 29, R. 866).
(a) 3CO(NH2)2=C303N3H3
(6) NH2CONH.CO.NHCONH2=C803N3H3+NHS
(c) 3C1+3CO(NH2)2=C3O3N3H3+2NH4C1+HC1+N
(d) 3COCla+3CO(NH2)2=2C303N3H3+6HCl.
464 ORGANIC CHEMISTRY
The evidence in favour of a symmetrical structure for cyanuric
acid depends on the successive substitution of the three chlorine
atoms of cyanuric chloride by amido-, methylamido-, and ethylamido-
groups, which always leads to the same acid-product, C3H3(NH2)-
(NHCH3)(NH.C2H5), whatever the order in which the three groups
are introduced (B. 32, 692).
Cyanuric acid crystallizes from aqueous solution with 2 molecules
of water ^^OsH^+sH^O) in large rhombic prisms. It is soluble
in 40 parts of cold water, and easily soluble in hot water and alcohol.
When boiled with acids it decomposes into carbonic acid and ammonia ;
when distilled it breaks up into cyanic acid. PC15 converts it into
tricyanogen chloride.
Characteristic salts of the tribasic cyanuric acid are the trisodium
salt and the amethyst-coloured cuprammonium salt (see above).
Normal Cyanuric Esters are formed (i) by the action of cyanogen
chloride on sodium alcoholates.
(2) A simpler procedure is to act on the sodium alcoholates with
cyanuric chloride or bromide (B. 18, 3263 and 19, 2063).
Methyl Cyanuric Ester, m.p. 135°, b.p. 263°.
Ethyl Cyanuric Ester, m.p. 29°, b.p. 275°.
The normal cyanuric esters on being digested with the alkalis, break up into
cyanuric acid and alcohol. They combine with six atoms of bromine. PC14
converts them into cyanuric chloride. Boiling gradually changes them to
isocyanuric esters.
Partial hydrolysis of the normal cyanuric esters by NaOH or Ba(OH)2
gives rise to normal dialkyl cyanuric acids, which, when heated, rearrange them-
selves into dialkyl isocyanuric acids (B. 19, 2067) :
O-Dimethyl Cyanuric Acid, C3N3(OCH8),.OH, m.p. 160-180°. O-Dimethyl
Cyanuric Acid Chloride, C8N3(OCH3)2C1, m.p. 81°, is prepared from cyanuric
chloride, methyl alcohol and zinc dust (B. 36, 3195)-
Esters of Isocyanuric Acid, Tricarbimide Esters, C8O3(NR)3, are formed
together with the isocyanic esters, when the latter are prepared by the distillation
of potassium cyanate with salts of alkyl sulphuric acid (p. 461). We have already
spoken of their formation as a result of the molecular transposition of the cyanuric
esters. Hence they are formed together with these, or appear in their stead in
energetic reactions — e.g. in the distillation of potassium cyanate with ethyl
sulphate, or when silver cyanurate is acted upon by alkyl iodides (B. 30, 2616).
They are solid crystalline bodies, soluble in water, alcohol, and ether, and may be
distilled without decomposition. They pass into primary amines and potassium
carbonate when boiled with alkalis, similarly to the isocyanates :
C3O3(NCH8)3+6KOH=3K2CO8+3NH2CH8.
Methyl Isocyanuric Ester, Trimethyl Carbimide, C3O3(NCH3)3, m.p. 176°,
b.p. 296°.
Ethyl Isocyanuric Ester, CaO3(NC2H6)8, m.p. 95°, b.p. 276°. It volatilizes
with steam.
Mixed n.-Isocyanuric Acid Esters. Methyl Cyanuric Dimethyl Ester,
m.p. 105°. is prepared, together with other
bodies, from silver cyanate and iodomethane by prolonged contact in the cold.
It can be sublimed undecomposed in the cold, and is hydrolyzed by hydrochloric
acid into ifi-methyl cyanuric acid, CH8N(C3O3N2H2), m.p. 296°. This also results
from the action of boiling alkalis on carbonyl dimethyl urea (p. 445).
Dimethyl Cyanuric Methyl Ester, CH3N<£°~^(£^>C(OCH8), m.p. 118°.
is produced from silver cyanurate and iodomethane in the cold. Hydrolysis
gives rise to Dimethyl tft-Cyanuric Acid, (CH3N)2(C3O8NH), m.p. 222°, which
is also obtained by heating w.-dimethyl cyanuric acid (see above) (B. 38, 1005).
HALOGEN COMPOUNDS OF CYANOGEN 465
Cyanuric Triacetate, CSN8O8(COCH8)3, m.p. 175° with decomposition, is
produced from silver cyanurate and acetyl chloride.
Cyanuric Tricarbonic Ester. (CSNSO3)(CO2C8H6), results from the polymeri-
zation of cyanocarbonic acid ester (p. 484). It is very slightly soluble, except
in chloroform (B. 38, 1010).
Cyanuric Triurea, (C3N3O3)(CONH2)3, is formed, together with cyanuric acid,
when urea is heated to 200°, or with cyanuric bromide. It is amorphous and slightly
soluble. It forms a trisodium salt, which crystallizes with sH2O (B. 38, 1010).
HALOGEN COMPOUNDS OF CYANOGEN AND ITS POLYMERS
The halogen compounds of cyanogen result from the action of
halogens on metallic cyanides, such as mercury cyanide, and on aqueous
hydrocyanic acid. The chloride and bromide condense to tricyanides
— C=N— C—
in which the C3N3 group | | constitutes the radical of
N=C — N
normal cyanuric acid. On account of their connection on the one
hand with cyanic and cyanuric acids and on the other with hydrocyanic
acid and its salts, the cyanogen halides can be looked on as being either
halogen compounds of the anhydride of n.-cyanic acid or the halogen
imides of carbon monoxide, e.g. ;
HN=C ClN=CorClCEEN HOCEEN
Hydrocyanic Acid. Cyanogen Chloride. H-Cyanic Acid.
Carbonyl Imide.
The formula XN:C receives substantiation from the fact that
cyanogen halides easily yield hydrocyanic acid ; also that the cyanogen
chloride and alcoholic sodium ethoxide do not yield the normal cyanic
ether (p. 461), but imidocarbonic ether, a reaction which is best ex-
plained as taking place with the intermediate formation of NaNC and
hypochlorous acid ester (p. 446) (C. 1092, I. 525, 862). Contrary to
this is the reaction of cyanogen chloride with mercaptides to form
alkyl thiocyanates (p. 468), and with ammonia to produce cyanamide
(P- 471)-
Cyanogen Chloride, CNC1, m.p. —5°, b.p. 15°, is produced by the action of
chlorine on aqueous hydrocyanic acid or on a cold mercuric cyanide solution,
or better, on a solution of potassium cyanide and zinc sulphate (C. 1907, 1.
746). It is a mobile liquid. After some time it passes spontaneously into
cyanuric chloride. With ammonia, it yields ammonium chloride and cyanamide,
NH2.NC. Alkalis decompose it into metallic cyanides and isocyanates.
Cyanogen Bromide, CNBr, m.p. 52°, b.p. 61°, is produced on adding a potassium
cyanide solution drop by drop to bromine, when well cooled (B. 29, 1822). For
the reaction of cyanogen bromide and tertiary amines, see p. 472, etc.
Cyanogen Iodide, CNI, sublimes at 45°, without melting, in brilliant white
needles.
These compounds are sparingly soluble in water, but they dissolve
readily in alcohol and ether. Their vapours have a penetrating odour,
provoking tears, and act as powerful poisons.
Cyanuric halides are converted into cyanuric acid when heated
with water.
VOL. I. 2 H
466 ORGANIC CHEMISTRY
Tricyanogen Chloride, Cyanuric Chloride, Solid Chlorocyanogsn
C1C— N==CC1
N— CC1=N
m.p. 146°, b.p. 190°, is produced (i) when liquid cyanogen chloride is kept in
sealed tubes, during which polymerization 189-05 Cal. are liberated (C. 1897, I.
284). It is formed (2) directly by leading chlorine into an ethereal solution of
HNC, or into anhydrous hydrocyanic acid exposed to direct sunlight (B. 19,
2056), or better, by slowly dropping HNC into a saturated solution of chlorine
in chloroform (B. 32, 691 ) ; (3) also by the distillation of cyanuric acid, H 3O3N3C3,
with PC15 (A. 116, 357). When boiled with water or alkalis, it breaks up into
hydrochloric and cyanuric acids (B. 19, R. 599). The chlorine atoms of cyanogen
chloride can be successively substituted by amido- and alkylamido-groups,
whereby cyanuramine chlorides, cyanuralkylamine chlorides (p. 474), melamines,
and alkyl melamines (p. 473) are formed (B. 32, 693).
OC.NC1.CO
Trichhryl Isocyanuric Acid, / ] , m.p. 245°, is formed by the action
NC1.CO.NC1
of chlorine on potassium cyAnurate. It is a nitrogen chloride, since it evolves
chlorine with hydrochloric acid, and regenerates cyanuric acid with NHS or
HaS (C. 1902, 1. 525, 804).
Cyanuric Bromide, C3N3Brs, m.p. above 300°, is produced (i) from bromo-
cyanogen in the presence of a little bromine. (2) On heating the anhydrous
bromide or its ethereal solution in sealed tubes to 130-140°. (3) By heating
dry potassium ferrocyanide and also ferricyanide with bromine at 250° (B. 16,
2893), or (4) on conducting HBr into the ethereal solution of CNBr (B. 18, 3262).
It is volatile at temperatures above 300°.
Cyanuric Iodide, CSN3I3, is produced by the action of hydriodic acid on
cyanuric chloride It is a dark brown, insoluble powder. At 200° it readily
breaks up into iodine and paracyanogen, (CN)W (B. 19, 599).
SULPHUR COMPOUNDS OF CYANOGEN, THEIR ISOMERS AND
POLYMERS
The two possible structurally isomeric thiocyanic acids correspond
with the two possible isomeric cyanic acids.
HS— C==N and NH=C=S.
Thiocyanic Acid, Iso thiocyanic Acid,
Sulphocyanic Acid. Sulphocarbimide.
The known thiocyanic acid and its salts (having the group NC.S — }
are constituted according to the first formula. Its salts are obtainec
from the cyanides by the addition of sulphur (p. 242), just as the iso-
cyanates result by the absorption of oxygen. The different union oj
sulphur and oxygen in this instance is noteworthy :
KNC+O=KN:CO KNC+S=KS.CN.
IsothiocarUmide, Sulphocarbimide , HN.CS, and its salts arc not
known. Its esters (the mustard oils) do, however, exist and are
isomeric with those of thiocyanic acid.
Thiocyanic Acid; Sulphocyanic Acid, HS.CN, m.p. 5° (approx.),
occurs in small quantities in the human stomach (B. 28, 1318).
and is obtained by distilling its potassium salt with dilute sulphuric
acid. At o° it forms a white crystalline mass and exercises
CYANOGEN SULPHIDE 467
strongly irritating action on the mucous membrane. On melting it
forms a yellow liquid which at ordinary temperatures solidifies to
yellow needles accompanied by a considerable evolution of heat. It is
very easily soluble in water, alcohol, and ether. The aqueous solution
also precipitates polymerization products at ordinary temperatures
after a short time (B. 4-0, 3166). Free thiocyanic acid and its soluble
salts colour a weakly acid solution of ferric salts a dark-red colour
(C. 1901, II. 199), constituting a highly sensitive reaction, which
depends on the formation of Fe2(CNS)6-}-9KSNC, when the potassium
salt is employed (B. 22, 2061). This reaction gives rise to the alter-
native name rhodonates (po'Sov, rose), which is sometimes given to
these compounds. Strong acids decompose thiocyanic acid into
hydrocyanic acid and perthiocyanic acid, C2N2S3H2 (p. 468).
The alkali thiocyanates. like the isocyanates, are obtained by fusing
the cyanides with sulphur.
Potassium Thiocyanate, KS.CN, crystallizes from alcohol in long,
colourless prisms, which deliquesce in the air. The sodium salt is very
deliquescent, and occurs in the saliva and urine of different animals.
When heated with zinc dust it is converted into potassium cyanide
(C. 1897, I. 270).
Potassium Selenocyanate, KSeNC, corresponds with the thiocyanate, and is
formed when potassium cyanide and selenium are melted together. It can be
crystallized from alcohol. * NOa causes the formation of Cyanogen Triselenide,
C2N2Se,, m.p. 132°, obtained as yellow leaflets from benzene solution. These
substances can be used for the preparation of pure selenium (B. 33, 1765).
Ammonium Thiocyanate, NH4S.CN, m.p. 150°, is formed on heating hydro-
cyanic acid with yellow ammonium sulphide, or a solution of ammonium cyanide
with sulphur. It is most readily obtained by heating CSa with alcoholic ammonia
(comp. Ammonium Dithiocarbamate, p. 449) :
CSa+2NH, > HtN.CSSNH4+2NH3 > NH4S.C.N-f(NH4)2S.
The salt crystallizes in prisms, which readily dissolve in water and alcohol.
At 170-180° molecular transposition into thiourea occurs (similarly to ammonium
cyanate, p. 438).
The salts of the heavy metals are mostly insoluble. The mercury salt,
Hg(CN.S)a, is a gray, amorphous precipitate, which burns on ignition and swells
up strongly (Pharaoh's serpents) ; silver salt, AgSNC, is a precipitate similar to
silver chloride. The volumetric method of Volhard is based on its production
(A. 190, i) ; lead sulphocyanide, Pb.(CNS)2.
i Cyanogen Sulphide, Thiocyanic Anhydride, (CN)2S, m.p. 65°, is formed when
j :yanogen iodide in ethereal solution acts on silver thiocyanate. It sublimes at
jo°, and dissolves in water, alcohol, and ether.
S CS,
„{ Xanthane Hydride, Imidothiodisulphazolidine, C2H2H2S8 — | >NH,
SC(NHK
s prepared by decomposing a concentrated solution of thiocyanic acid, whereby
lydrocyanic acid is driven off. It forms prisms soluble with difficulty in water
md most other solvents.
. Dithiocyanic Acid, C2N2H2S2=HSCS,NH.CN, is produced when alkalis act
n the cold on xanthane hydride, when sulphur is thrown out and the dipotassium
alt of the acid is formed. It is also prepared from cyanamide, carbon disulphide,
,nd alcoholic potassium hydroxide. These modes of formation show the acid
o be cyanamidodithiocarbonic acid, (HS)2C=NCN or HS2CNHCN. The free
cid consists of yellow needles, and is unstable, the potassium salt even decom-
iosing in aqueous solution into two molecules of potassium thiocyanate ; Dimethyl
ister, (CH3S)2C : NCN, m.p. 57°, is decomposed by hydrochloric acid at 200° into
* • lercaptan, NHa, and COj.
468 ORGANIC CHEMISTRY
Perihiocyanic Acid, CaNaS8Ha; salts, Nf |, are formed when an
N
alkaline solution of dithiocyanic acid is boiled with sulphur. The acid is struc-
turally isomeric with xanthane hydride, which possesses a neutral reaction, into
which it very rapidly changes in acid solution; Dimethyl Ester, CtN2S(SCH3)2,
m.p. 42°, b.p. 2jg°, is decomposed by hydrochloric acid into CH3SH, NH4C1,
and CO,. The following shows the connection between these peculiar reactions
(A. 331, 265) :
NC S - CSV HS— CS.
3HSNC -- > I + I >NH - > S+ >NH
H
S.C(NHK
Thlocyanic Acid. Xanthane Hydride. Dithiocyanic Acid.
X(SK)— S Acids /CS - S
K( I - ^HN<
XC(SK)=N XC(NH)— S
DIthiocyanate. Perthiocyanate. Xanthane Hydride.
Cyanogen Sulphide, (CNS), and Pseudocyanogen Sulphide, are the yellow
amorphous products which result when the alkali and alkali earth thiocyanates
are oxidized. Cyanogen sulphide is also formed when dry thiocyanates are
treated with dry halogens, whilst pseudocyanogen sulphide, which appears to
be a mixture of various substances in varying proportions, is obtained from an
aqueous solution of thiocyanates with halogens, nitric acid, H2Oa, or persulphates.
Cyanogen sulphide, and to a much smaller extent pseudocyanogen sulphide,
when treated with water or sodium hydroxide solution yields canarine, CtNgS7H,O,
a yellow substantive dye for cotton (one which does not require a mordant).
It possesses a weakly acid reaction. Together with canarine there is formed
a yellow, non-dying substance. C3N4H4S2O, which is decomposed by alkali
sulphydrates into thioammeline, (CN)3(NHa)2SH, and dithiomelanurenic acid,
aminodithiocyanuric acid, (CN)8(NH2)(SH)2 (J. pr. Ch. [2] 64, 439).
Alkyl Thiocyanates, esters of normal sulphocyanic acid are obtained (i) by
distilling potassium thiocyanate with salts of sulphuric acid ethers or with alkyl
iodides :
KSCN+CaH5I=C8H6SCN+KI.
Further, (2) by the action of CNC1 on salts of the mercaptans :
C2H6SK+CNC1=C2H5SCN + KC1.
They are liquids, insoluble in water, and possessing a leek-like odour. Nascent
hydrogen (zinc and sulphuric acid) converts them into hydrocyanic acid and
mercaptans :
CaH6S.CN+Ha=HNC-f-C2H6.SH.
On digesting with alcoholic potassium hydroxide, potassium thiocyanate is formed,
whilst the isomeric mustard oils do not yield any potassium thiocyanate.
Boiling nitric acid oxidizes them to alkyl sulphonic acids (p. 146) with separation
of the cyanogen group. This would prove that the alkyl group in these bodies
is linked directly to sulphur.
Methyl Thiocyanic Ester, CH3SCN, m.p. 133°, D0 = 1-080. When heated to
180—185° it is converted into the isomeric methyl isothiocyanic ester. This
conversion is more readily effected with allyl thiocyanate (see Allyl Mustard Oil,
p. 470; C. 1901, II. 1115).
Ethyl Thiocyanic Ester, C2HBS.CN, b.p. 142°.
Isopropyl Thiocyanic Ester, C3H7SCN, b.p. 152°.
Allyl Thiociocyanic Ester, C,H5S.CN, b.p. 161°, and rapidly changes to
isomeric allyl mustard oil.
Thiocyanic Compounds derived from Aldehydes, Glycols, Hydroxy-
Ketones and Hydroxy-Fatty Acids.
Methylene Thiocyanate, Dithiocyanomethane, CH2(SCN)2, m.p. 107° (B. 7,
1282), is oxidized to methylene disulphonic acid (p. 210) (C. 1898, I. 886).
Ethyiene Thiocyanate, Dithiocyanoethane, NCS.CH2CHa.SCN, m.p. 90° (B. 23,
1083). Ethyiene Selenocyanide, m.p. 138° (B. 23, 1092).
MUSTARD OILS 469
Thiocyanacetone, CNSCH2.CO.CH3, D20=ri8o, is formed from
barium thiocyanide and chloracetone (p. 224). It is an oil with scarcely
any colour. It is somewhat soluble in water, and very readily soluble
in ether. The alkali carbonates cause a rearrangement into methyl
CH.— C— N^
oxythiazole, \\ V.OH (B. 25, 3648).
HC — S
Thiocyanacetic Acid, Sulphocyanacetic Acid, CNS.CH2CO2H, is formed by
the action of chloracetic acid on KCNS. It is a thick oil ; ethyl ester, b.p.
about 220°, prepared from chloracetic ester.
On boiling the latter with concentrated hydrochloric acid, it takes up water,
CH2— S v
loses alcohol, and thiocyanacetic acid, \ )>CO, is formed (A. 249, 27).
CO— NHX
Many of the reactions of this cyanacetic acid are better explained by the con-
stitutional formula, SCNCH2COOH (or perhaps HC<^>CHCOOH) (comp. J. pr.
Ch. [2] 66, 172).
These heterocyclic bodies, derived from the products of the interaction of
ammonium thiocyanate with a-chloroketones and a-chloro-fatty acids, belong to
the class of thiazoles (Vol. II.).
Mustard Oils, Esters of Isothiocyanic Acid, Alkyl Thiocarbimides.
The esters of isothiocyanic acid, HN : CS, not known in a free
condition, are termed mustard oils, from their most important repre-
sentative. They may also be considered as sulphocarbimide deri-
vatives.
They are produced (i) by the rearrangement of the isomeric alkyl
\ thiocyanates on the application of heat (p. 468) :
C8H5SNC > C3H6NCS.
(2) From primary amines. These combine (a) with CS2 in ethereal
solution to form alkyl ammonium alkyl dithiocarbamates (B. 23, 282).
(b) On adding silver nitrate, mercuric chloride (B. 29, R. 651) or ferric
t chloride (B. 8, 108) to the aqueous solution of these salts, formed with
• primary amines, and then (c) heating to boiling the metallic com-
pounds first precipitated, whereby they are decomposed into metallic
sulphides, hydrogen sulphide and mustard oils.
S.NH3(C2H5)
2CS=NC2H5
:S
The mustard oil test for the detection of primary amines (p. 163)
;s was worked out by A. W. Hofmann.
I
*" Iodine, too, forms mustard oils from the alkyl-ammonium salts of the alkyl
dithiocarbamic acids (comp. isothiouranic disulphides).
(3) By the action of dialkyl thioureas (p. 452) with phosphorus
pentoxide (B. 14, 985) ; and (4) from isocyanic esters and P2S6 (B.
f. 18, R. 72).
Properties. — The mustard oils are liquids, almost insoluble in
water, and possess a very penetrating odour, which provokes
tears. They boil at lower temperatures than the isomeric thiocyanic
esters.
Reactions. — (i) When heated with hydrochloric acid to 100°, or
470 ORGANIC CHEMISTRY
with H2O to 200°, they break up into primary amines, hydrogen
sulphide, and carbon dioxide (C. 1899, I. 885) : *
C1HiNCS+2HaO=CaH5NHa+COa+HaS.
(2) When heated with a little dilute sulphuric acid, carbon oxy-
sulphide, COS, is formed, together with the ainine. (3) When heated
with carboxylic acids they yield alkylated acid amides and COS ; and
(4) with carbonic anhydrides, diacidyl amides and COS (B. 26, 2648).
(5) Nascent hydrogen (zinc and hydrochloric acid) converts them into
thioformaldehyde (p. 209) and primary amines :
C2H6NCS+2Ha=CSHa+C2H8NHa.
(6) When the mustard oils are heated with absolute alcohol to 100°,
or with alcoholic potassium hydroxide, they pass into sulphour ethanes.
(7) They unite with ammonia and amines, yielding alkyl thioureas
(q.v.). (8) Upon boiling their alcoholic solution with HgO or HgCl2,
a substitution of oxygen for sulphur occurs, with formation of esters
of isocyanic acid, which immediately yield the dialkyl ureas when
treated with water (see p. 440). (9) Consult A. 285, 154, for the action
of the halogens on the mustard oils.
Methyl Mustard Oil, CH8NCS, Methyl Isothiocyanic Ester, Methyl Sulpho-
carbimide, m.p. 34°, b.p. 119°.
Ethyl Mustard Oil, b.p. 133°, D0=i'oi9. Propyl Mustard Oil, b.p. 153°.
Isopropyl Mustard Oil, b.p. 137°.
n.-Butyl Mustard Oil, b.p. 167°. Isobutyl Mustard Oil, b.p. 162°.
Tert. -Butyl Mustard Oil, b.p. 142°. n.-Hexyl Mustard Oil, b.p. 212°. Heptyl
Mustard Oil, b.p. 238° (B. 29, R. 651). Sec.-Octyl Mustard Oil, b.p. 232°.
On account of its occurrence the following is noteworthy: sec.-Butyl Mustard
Oil, CS:NCH<C£jj 6, b.p. 159*5°, Dusso-944, is found in the ethereal oils of spoon
wort (or scurvy grass) (Cochlearia officinalis) ; it is dextro-rotatory to polarized
light, and on decomposition gives a dextro-rotatory sec.-butylamine (C. 1901,
II. 29).
The most important of the mustard oils is the common or —
Allyl Mustard Oil, Allyl Isothiocyanic Ester, C3H5N : CS, b.p.
150*7°, D10= 1*017, the principal constituent of ordinary mustard
oil, is obtained by distilling powdered black mustard seeds (Sinapis
nigra), or radish oil from Cochlearia armoracia, With water. Mus-
tard seeds contain potassium myronate (see Glucosides, Vol. II.),
which in the presence of water, under the influence of a ferment,
myrosin (also present in the seed), breaks up into dextrose, potassium
hydrogen sulphate, and mustard oil.
The reaction occurs even at o°, and there is a small amount of allyl
thiocyanate produced at the same time :
C,0H18KN010S2=C6Hia08
Mustard oil is artificially prepared by distilling allyl iodide or
bromide with alcoholic potassium or silver thiocyanate (Gerlich, A.
178, 80 ; C. 1906, II. 1063) :
KSCN+C,H5I=C8N6NCS + KI ;
a molecular rearrangement occurs here.
Pure allyl mustard oil is a liquid not readily dissolved by water.
CYANAMIDE AND THE AMIDES OF CYANURIC ACID 471
It has a pungent odour and causes blisters upon the skin. When
heated with water or hydrochloric acid the following reaction ensues :
C8H5NCS+2H1O==CO2+H2S+C3H6NH1.
It unites with aqueous ammonia to form allyl thiourea (p. 452).
When heated with water and lead oxide it yields diallyl urea (p. 440).
Acyl Thiocarbimides, or Acyl Thiocyanates, are produced by the action of fatty-
acid chlorides, dissolved in benzene, on lead thiocyanate. Acetyl Thiocyanate
Thiocarbamide, CHSCO(NCS), Valeryl Thiocarbimide, C4H9CO.NCS (B. 29, R. 85),
and Carboxethyl Thiocarbimide, C2HfiOCO.NCS, b.p.2i 66° (B. 29, R. 514), were
obtained in this manner. Amines combine with them to form either alkylamides,
AcNHR and aminothiocyanates, or acyl alkyl thioureas, AcNHCSNHR (C. 1905,
I. 1098 ; 1906, II. 773, etc.).
Thio- or sulphoeyanurie Acid, (HS)3C3N3, corresponds with cyanuric acid.
Isothiocyanuric acid is as little known as isocyanuric acid. Thiocyanuric acid
results from cyanuric chloride (p. 466) and potassium hydrosulphide. It consists
of small yellow needles, which decompose but do not melt above 200°.
Its esters result when cyanuric chloride and sodium mercaptides interact,
and by the polymerization of the thiocyanic esters, RS.CN, when heated to 180°
with a little HC1. More HC1 causes them to split up into cyanuric acid and
mercaptans.
Methyl Ester, '(CH3S)3C3N3, m.p. 188°, yields melamine with ammonia
(P- 473) (B. 18,2755). Monothiocyanuric Dimethyl Ester, (SH)(OCH,)2C3N3, is
prepared from 0-dimethyl cyanuric chloride (p. 464) and KSH. When hydro-
lyzed with HC1, it yields monothiocyanuric acid, (HS)(HO)aC3N3, which gives a
characteristic mercury salt (B. 36, 3196).
Isothiocyanuric Esters, (RN)8C3S3> appear to have been formed by the poly-
merization of mustard oils with potassium acetate (B. 25, 876).
CYANAMIDE AND THE AMIDES OF CYANURIC ACID
Cyanamide, CN.NH2, m.p. 40°, the nitrile of carbamic acid, absorbs
water and passes into urea, the amide of carbamic acid. It shows
certain reactions, which would rather point to its being NH=C=NH,
carbodiimide. It is formed (i) by the action of chloro- or bromo-
cyanogen on an ethereal or aqueous solution of ammonia (Bineau,
1838 ; Clolz and Cannizzaro, 1851) :
CNC1+2NH3=CN.NH2+NH4C1 ;
and also (2) by the desulphurizing of thiourea by means of mercuric
chloride, lead peroxide, or mercuric oxide (B. 18, 461 ; A. 331, 282) ;
or lead hydroxide in presence of alkalis (C. 1897,
(3) By mixing urea with thionyl chloride :
CO(NH2)2+SOClt=CN,H2-f-SO2+2HCl.
(4) Salts of cyanamide with sodium, calcium, etc., are prepared
on a technical scale, and yield cyanamide when decomposed with acids :
(a) Sodium amide and carbon or carbon compounds heated to
400-600° produce sodium cyanamide (C. 1905, II. 1650, etc.) :
CNtNa,+4H.
ORGANIC CHEMISTRY
At 800° another atom of carbon enters into reaction and sodium
cyanide, NaNC, is produced (C. 1904, I. 64).
(b) Calcium carbide, mixed with certain substances such as calcium
chloride, and when heated to high temperatures, absorbs nitrogen and
is converted into calcium cyanamide (C. 1905, II. 1059 ; B. 40, 310,
etc.) :
CtCa+N, > CN2Ca+C.
(c) Carbonates, such as these of barium and lead, react with
ammonia at temperatures of incandescence, yielding metallic cyan-
amides (C. 1913, 1. 677) :
PbCO,+2NH8 > CNjPb-f 3HtO.
Cyanamide forms colourless crystals, easily soluble in water,
alcohol, and ether. If heated it polymerizes to dicyandiamide and
tricyantriamide (melamine).
Salts. — It forms salts with strong acids, but these are decomposed by
water. It also forms salts with metals. An ammoniacal silver nitrate
solution throws down a yellow precipitate, CN.NAg2,fcom its solutions.
Reactions. — (i) By the action of sulphuric acid or hydrochloric
acid, it absorbs water and becomes urea (p. 439). (2) H2S converts
it into thiourea (p. 451), and (3) NH3 into guanidine (p. 455), whilst
substituted guanidines are produced upon introducing the hydro-
chlorides of primary amines. (4) Alcohols and hydrochloric acid
change cyanamide into isourea-ether (p. 446).
Mono- Alkyl Cyanamides are obtained (i) by the action of cyanogen chloride
on primary amines in etheral solution, or from aqueous solutions of amines
and potassium cyanide with bromine (C. 1906, II. 1046) ; (2) by heating alkyl
thioureas with mercuric oxide and water.
Methyl Cyanamide, CN.NHCH3, and Ethyl Cyanamide, CN.NHC2H5, are
non-crystallizable, thick syrups with neutral reaction. They are readily con-
verted into polymeric isomelamine derivatives.
Allyl Cyanamide, CN.NHC3H5, called Sinamine, is obtained from allyl
thiourea. It is crystalline and polymerizes readily into triallyl melamine.
Dialkyl Cyanamides are formed from CNBr, or KNC+Br (C. 1906, II. 1046)
and sec.- bases ; also from silver cyanamide, CN.NAg2, and iodo-alkyls. Further,
from CNBr and tert.-amines, whereby the first formed trialkyl cyanammonium
bromide, R.R'R*N<Br , probably parts with bromo-alkyl — the smallest of the
alkyl radicals being lost. Alkyl and benzyl radicals, however, behave excep-
tionally, and are split off even more easily than the methyl group (B. 35, 1279).
On the" use of these methods for breaking down tertiary cyclic amines, see B. 40,
3914. Dimethyl Cyanamide, Cyanodimethylamine, CNaN(CH3)2, b.p.,0 68° ; Ethyl
Cyanamide, CN.N(C2H6)2, b.p. 188°, is decomposed, when boiled with hydrochloric
acid, into CO2, NH3 and diethylamine NH(C2H5)2. Cyanodipropylamine,
b.p.1$ 89°. Cyanodiamylamine, b.p.10 130°. Treated with ammonia and
sulphuretted hydrogen in alcoholic solution, the cyano-dialkylamines are easily
converted into the corresponding thioureas (B. 32, 1872).
An example of a dialkyl-substituted carbodiimide is Di-n.-propyl Carbodi-
imide, C(=N.C3H7)2, b.p. 177°, which is produced from sym.-dipropyl thiourea
and H2O (B. 26, R. 189).
For the conversion of cyanamide into cyanamidocarbonic acid, cyanamido-
dicarbonic acid, cyanamidodithiocarbonic acid, see pp. 445, 467.
AMIDES OF CYANURIC ACID
473
AMIDES OF CYANURIC ACID AND IMIDES OF ISOCYANURIC ACID
Three amides are derived from cyanuric acid, and three imides from hypothetical
isocyanuric acid, the pseudo- form of cyanic acid (p. 463) :
OH
NH,
N
I!
HO.C
NH,
NH,
N
I
CO.H
N
II
HO.C
N
I
C.OH
N
II
HO.C
I
C.
NHa
Normal Cyanuric
Acid.
Cyanuromonamide,
Ammelide.
NH
Cyanurodiamide,
Ammeliae.
H.NC C.NH2
\NX
Cyanurotriamidf
Melamine.
/'
HN
OC CO
\N/
H
Isocyanuric
Acid.
HN
NH
OC CO
\N/
H
Isocyanuromoniinide.
NH
NH
II
H
A
HN NH
HN NH
1 |
OC C:NH
HN:C C:NH
\N/
\N/
H
H
Isocyanurodiimide,
Isoammeline.
Isocyanurotriimide
Isomclamine.
Melamine, Cyanur amide, C3N3(NH?)3, is obtained as thiocyanate by :
(i) The rapid heating of ammonium thiocyanate (B. 19, R. 340) (together with
melam and melem) ; (2) the polymerization of cyanamide or dicyandiamide on
heating to 150° (together with melam) ; (3) by heating methyl trithiocyanuric
ester to 180° with concentrated ammonia; and (4) by heating cyanuric chloride
to 1 00° with concentrated ammonia (B. 18, 2765) :
C,N3Cls+6NH,=CaNs(NHa)3+3NH4Cl.
Melamine is nearly insoluble in alcohol and ether. It crystallizes from hot
water in shining monoclinic prisms. It sublimes on heating and decomposes
into mellon and NH3. It forms crystalline salts with i equivalent of acid.
Molten potassium hydroxide converts it into potassium cyanate.
On boiling with alkalis or acids melamine splits off ammonia and passes
successively into Ammeline, C3H6N6O =C3N3(NH2)2.OH, a white powder insoluble
in water, but soluble in alkalis and mineral acids (B. 21, R. 789); Ammelide,
M5/ai7M^m'c^«W,C3H4N4Oa=C3N3(NH2)(OH)2, a white powder which forms salts
with both acids and bases, and finally cyanuric acid, C3N3(OH)3 (B. 19, R. 341).
Melanurenio Acid is formed from melam and melem (see below), when
heated with concentrated H2SO4 (B. 19, R. 341 ; 18, 3106).
Melam, C6H,N11 = [(NH2)2C3N3]2NH (?),
Melem, C6H6N10 = [(NH2)C3N3(NH)]2 (?).
and Mellon, C.H3N, =C,N3(NH),C8N3 (?),
led by heating ammonium thiocyanate, the first two at 200°, and the last
at red heat. They are amorphous white substances (B. 19, R. 340).
Alkyl Derivatives of the Melamines.
Whilst melamine is only known in one form as cyanurotriamide, two series
of isomeric alkyl derivatives exist — obtained from normal melamine and hypo-
thetical isomelamine :
(I) C,N3(NHR')3 and C3N3(NR'2)3.
Normal Alkyl Melamines.
(2) C,N3H3(NRO,.
Isoalkyl Melamines.
474 ORGANIC CHEMISTRY
These are distinguished from each other not only by the manner of their
preparation, but also by their reactions.
(1) Normal Alkyl Melamines are obtained from the trithiocyanuric esters,
C8N8(S.CH3)8, and from cyanuric chloride, CSN3C13, upon heating with primary
and secondary amines (B. 18, R. 498) :
C8N3C13+3NH(CH3),=C,N8[N(CH3)2]S.
Heating with concentrated hydrochloric acid causes them to split up into cyanuric
acid and the constituent alkylamines.
Trimethyl Melamine, C3N3(NH.CH8)8, m.p. 130°, dissolves readily in water,
alcohol and ether. Triethyl Melamine, C8N3(NH.C2H6)3, crystallizes in needles,
m.p. 74° C.
Methyl Ethyl Melamine, C8H3(NHC2H6)(NHCH3)NH2, m.p. 176°, is prepared
from cyanuric chloride by the successive substitution of NH2-, CH8NH-, and
C2H5NH- groups, it being immaterial in which order the groups are introduced.
On the significance of these compounds to the constitution of cyanuric chloride,
see p. 463.
Hexamethyl Melamine, C3N3[N(CH8)2]8, m.p. 171°, Hexaethyl Melamine,
C3N8[N(CaH5),]8, is a liquid, which is decomposed by hydrochloric acid into
cyanuric acid and 3 molecules of diethylamine.
(2) Alkyl Isomelamines are formed by the polymerization of the alkyl
cyanamides, CN.NHR' (p. 472), upon evaporating their solutions, obtained from
the alkyl thioureas on warming with mercuric oxide and water. They are
crystalline bodies. When heated with hydrochloric acid they yield cyanuric
esters and ammonium chloride (B. 18, 2784).
Trimethyl Isomelamine, C3N3(CH3)3(NH)8+3H2O, m.p. 179°, anhydrous. It
already sublimes at about 100°. Triethyl Isomelamine, C3N8(C2H6)3(NH)3-}-4H2O,
consists of very soluble needles. Consult Hofmann, B. 18, 3217, for the phenyl
derivatives of the mixed melamines (also amide and imide bodies).
Cyanuramine Chlorides.
Cyanuramine Di chloride, C3N3C12(NH2), corresponds with cyanuric monamide
or ammelide (p. 473) or melanurenic acid ; and Cyanurodiamine Monochloride,
C3N3Cl(NHj)2> with cyanuric diamide or ammeline. The former substance is
formed by the action of ammonia on an ethereal solution of cyanuric chloride ;
the latter by aqueous ammonia on the chloride. Similar conditions of experi-
ment applied to methylamine and ethylamine give rise to the following sub-
stances: Cyanuromethylamine Dichloride, C8N8C12(NHCH3), m.p. 161°; Cyanuro-
ethylamine Dichloride, C3N3Cl2(NHC2He)2, m.p. 107°, Cyanuraminomethylamine
Chloride, C8N3C1(NH2)(NHCH3) ; Cyanuraminoethylamine Chloride, C3N8C1-
NH(C2H8)(NH2), m.p. 176° ; Cyanuromethylaminoethylamine Chloride, C8H3C1-
(NHCH8)(NHC2H5), m.p. 235°. Ethylamine, methylamine and ammonia convert
the three last-named chlorides into methyl ethyl melamine.
Cyanuramine Hydrides, Guanamines. The hydrogen compound, hydrocyanuric
acid or trihydrocyanic acid, HC<rfr~r H^*' corresponding w^ cyanuric chloride,
is unknown. However, reduction of Cyanuramine dichloride forms Monamino-
hydrocyanuric Acid, C8N8H2.NHt, m.p. 225°, whilst cyanodiamine monochloride
yields diaminohydrocyanuric acid. Guanamines are the bases formed when
fatty acid guanidine salts are heated to 22O°-23O°, whereby water and ammonia
are driven off (Nencki, B. 9, 228). The simplest guanamine is formed when
guanidine formate is heated, or when biguanide (p. 457) is acted on by chloro-
form and potassium hydroxide solution (B. 25, 535). This For mo guanamine,
HC<^N^C(NH2i^>N' m'p< 325°' is identical with diaminohydrocyanuric acid
(see above). Homologous guanamines are derived from this, by the replacement
of the H-atoms in the CH- group by alcohol radicals.
Acetoguanamine, CH8C<^£|]™2j>H, m.p. 265°, is produced from guani-
dine acetate. Concentrated sulphuric acid at 150° converts it into aceto-
guanamide (comp. Acetyl Urethane, p. 436).
Ketenes, Carbomethenes, discovered by Staudinger in 1905, show a great
similarity to the derivatives of isocyanic acid or the carbimides, such as
KETENES 475
alkyl isocyanates and acyl isocyanates (pp. 461, 462). By analogy to carbimides,
they can be called carbomethenes :
CO=NCH3 CO=CH,
Methyl Isocyanate Ketene
Carbo-methylimide. Carbo-methene.
The ketenes can also be considered as internal anhydrides of monocarboxylic
acids, and are then comparable with carbon monoxide (p. 267).
They are prepared (i) by the action of zinc on o-bromo-fatty acid bromides
in indifferent solvents :
Zn
CH2Br— COBr > CH2=CO + ZnBr,
(CH2)2CBr— CBr — V (CH8),C=CO + ZnBr,.
Also, by the action of tertiary amines, such as triethylamine, on carboxylic acid
chlorides, whereby hydrochloric acid is split off, ketenes probably are formed,
but they polymerize instantaneously (see below).
(2) When the vapours of acetic anhydride are passed over a platinum wire
heated electrically to redness, or through an electric arc, ketenes are formed :
CH8CO.O.COCH3 > 2CH2=CO+H20.
(3) By heating dialkyl malonic anhydride (B. 41, 2208) :
r(C2H,)aC CO! (C2H6)2C
Up to the present time the following members have been prepared : Ketene,
carbomethene, CH8 : CO, m.p. —151°, b.p. —56°, a colourless, poisonous liquid,
having an odour of chlorine and acetic anhydride. Methyl Ketene, Carbomethyl
Methene, Carboethylidene, CH3CH : CO, and Ethyl Ketene, Carboethyl Methene,
Carbopropylidene, C2HBCH : CO, have only been obtained in ethereal solution.
Dimethyl Ketene, Carbodimethyl Methene, Carboisopropylene, (CH8)2C:CO
(comp.p. 290), m.p. — 97*5°, b.p. 34°, is a very mobile, wine-yellow liquid. Diethyl
ketene, (C2HS)2C3CO2, b.p. 92°, is a yellow liquid.
Reactions. — The lower members are only stable at low temperatures, but
somewhat more so in solution. They polymerize with extraordinary ease
spontaneously or under the influence of zinc bromide or tertiary amines. Ketene
gives rise to dehydracetic acid, and dimethyl ketene to tetramethyl-cyclobutane-dione :
(C2H5)3N -
4CH2:CO > C8Hg04, (CH3)2C : CO > (CH3)4C4Ot.
The ketenes show none of the characteristic ketone reactions. Like the
carbimides, they easily combine with water to form carboxylic acids or anhydrides ;
with alcohols to carboxylic esters, with ammonia or amines to carboxylic acid
amides :
H20 H20
CH3N=CO > CH,NHCOOH, etc. CH2=CO > CH3COOH
CH3OH C6HUOH
CH8N =CO > CH3NHCOOCH8 CH2=CO > CH,COOC6Hn
CH8N=CO %• CH,NHCONH2 (p.46i), CH2=CO > CH8CO.NH8.
Bromine is taken up to form a-bromo-fatty acid bromides.
In contradistinction to the lower ketenes, dimethyl ketene combines with
tertiary amines, such as pyridine, quinoline, etc., to form stable bodies,
CBH5N[(CH3)2C:CO]2, an oil ; C8H7[(CH8)2C : CO]2, m.p. 83°, which, when boiled
with hydrochloric acid, form complex intermediate compounds and ultimately
break down into the amine and isobutyric acid. Stable compounds are also
formed with substances possessing the group — C=N— (isocyanates, mustard
oils, Schiffs bases). Oxygen is absorbed to form a very explosive peroxide
(A, 356, 51; B. 41, 1025). Closely connected with the ketenes is carbon suboxide,
CgOjj, obtained from malonic acid and described with it (p. 487). See also
diphcnyl ketene and diphenylene ketene (Vol. II.)*
476 ORGANIC CHEMISTRY
10. DIBASIC ACID, DICARBOXYLIC ACIDS
A. PARAFFIN DICARBOXYLIC ACIDS, OXALIC ACID SERIES,
CnH2n.204, CnH2n(C02H)a
The acids of this series contain two carboxyl groups, and are there-
fore dibasic. They differ very markedly from each other on the
application of heat, depending upon the position of the carboxyl
groups. Oxalic acid, CO2H.CO2H, the first member of the series, breaks
down on heating chiefly into CO2, CO and water, and in part into CO2
and formic acid. The nature of the latter decomposition is cha-
racteristic of all those homologues of oxalic acid, in which the two
carboxyls are attached to the same carbon atom — the j3-dicarboxylic
acids, e.g. malonic acid, CH2(CO2H)2. The latter acid and all mono-
and di-alkyl malonic acids decompose on heating at the ordinary pressure
into acetic acid (also mono- and di-alkyl acetic acids) with the elimina-
tion of C02. Malonic acid is the type of these acids :
Malonic Acid. Acetic Acid.
On the other hand, when the two carboxyl groups are attached to
adjacent carbon atoms, as in ordinary or ethylene succinic acid,
CO2H.CH2CH2.CO2H, and in the alkyl ethylene succinic acids, these
y-dicarboxylic acids, when heated, do not give up CO2, but part with
water and pass into anhydrides, which can also be prepared in other
ways, whereas the anhydrides of the malonic acids are not known
(p. 488). Ethylene succinic acid is the type of these acids :
CH,COOH CH2COV
I =|
CH2COOH
Ethylene Succinic Succinic Anhydride.
Acid.
Glutaric acid, or normal pyrotartaric acid, C02H.CH2.CH2.CH2.-
C02H, in which the two carboxyl groups are attached to two carbon
atoms, separated by a third, behaves in this manner. Like succinic
acid, it yields a corresponding anhydride when it is heated. All
acids, which can be regarded as alkyl glutaric acids, behave
analogously :
Glutaric Acid. Glutaric Anhydride.
When the carbon atoms, carrying the carboxyl groups, are separated
by two carbon atoms from each other — e.g. adipic acid, CO2H.CH2.-
CH2.CH2.CH2.CO2H — they do not influence one another on the appli-
cation of heat. Adipic acid volatilizes undecomposed.
Therefore, the numerous paraffin dicarboxylic acids are arranged
in different groups, and, after oxalic acid, the malonic acid group, the
succinic acid group, and the glutaric acid group will be discussed.
Then will follow adipic acid, suberic acid, sebacic acid and others
which do not belong to any one of the three acid groups mentioned
above.
SATURATED DICARBOXYLIC ACIDS 477
Formation. — The most important general methods are —
(i) Oxidation of (a) diprimary glycols, (b) primary hydroxyalde-
hydes, (c) dialdehydes, (a) primary hydroxyacids, and (e) aldehyde
acids (p. 400} :
CH2.OH COOH CHO CO2H CO,H
CH2.OH > CH2OH ino" ^ COH " ^ C02H
Glycol. Glycollic Acid. Glyoxal. Glyoxylic Acid. Oxalic Acid.
The dibasic acids are also formed when the fatty acids, CnH2nO2,
and the acids of the oleic acid series, as well as the fats, are oxidized
by nitric acid. Certain hydrocarbons, CnH2n, have also been converted
into dibasic acids by the action of potassium permanganate.
(2) By the reduction of unsaturated dicarboxylic acids :
CHCO.H CH2COaH
II +2H= |
CHCO2H CH2CO2H
Fumaric Acid. Ethylene Succinic Acid.
(3) When hydroxydicarboxylic acids and halogen dicarboxylic
acids are reduced.
Nucleus- synthetic Methods of Formation. — These are very numerous.
(4) When silver in powder form (B. 2, 720) acts on mono-iodo
bromo-) fatty acids :
CH2CH2CO2H
2l.CH2CH2COaH+2Ag = | +2AgI.
CH2CH2CO2H
/S-Iodopropionic Acid. Adipic Acid.
See trialkyl-glutaric acids for the abnormal course of this re-
action when a-bromisobutyric acid is used.
(5«) Conversion of monohalogen substituted fatty acids into cyan-
derivatives, and boiling the latter with alkalis or acids (pp. 252 and
280):
Cyanacetic Acid. Malonic Acid.
(56) Conversion of the halogen addition products of the alkylenes,
CnH2n, into cyanides and the saponification of the latter :
CH2.CN CH2.CO2H
| +4H20 = I +2NH,.
CH3.CN CHa.C02H
Only the halogen products having their halogen atoms attached to two
different carbon atoms can be converted into dicyanides.
Since dicarboxylic acids or their esters or anhydrides can be reduced
to hydroxycarboxylic acids or their lactones (p. 372) by means of
nascent hydrogen (from sodium and alcohol, electrolysis, etc.), and
these can be converted into cyanocarboxylic acids, vid halogen-car-
boxy lie acids, it follows that these processes provide a means for the
478 ORGANIC CHEMISTRY
synthesis of progressively higher members of the dicarboxylic acid
series :
C02H.CO2H > CH.OH.C02H > CH2C1CO2H > CN.CH2CO2H
> C03H.CH2COaH.
(5c) y- and ^-Lactones, when heated with potassium cyanide and
subsequently hydrolyzed, are converted directly into a higher acid
(cornp. p. 373) (C. 1905, II. 755) :
(CH8)2C.C02R H (CH3)2C.CHas^ KNC (CH3)2C.CH2.CN RQH
HaC.COaR HaC.CO / H2CCOOH HC1
(CHs)aC.CHa.COaR H ^ (CH3)X.CHa.CHa
HaC.COaR CH2.COO
(6) In the synthesis of the mono- and di-alkyl malonic acids it is
of the first importance to replace the hydrogen atoms of the CH2 group
of the malonic acid in its esters by alkyl groups, just as was done in
the case of acetoacetic ester (p. 413). This reaction will be more fully
developed in the malonic acid group (p. 487).
(7) By the electrolysis of concentrated solutions of the potassium
salts of the dicarboxylic acids mono-alkyl esters (see electrolysis of
the mono-carboxylic acids (pp. 73, 83, 253) :
CH2CO2C2H6 CH2COaC2H5
2 I +2HaO = I +2CO.+2KOH+2H.
C02K CH2C02C2H5
Potassium Ethyl Succinic Ethyl
Malonate. Ester.
(8) A very general method for the synthesis of dibasic acids is
based upon the decomposition of 0-ketone dicarboxylic esters. Acid
residues are introduced into the latter and the products decomposed
by concentrated alkali solutions (p. 415) :
Acetomalonic Ester. Malonic Acid.
CH3CO.CHCOaC2.H5 _ CH2COaH
CH?C02C2H, CH2C02H
Acetosuccinic Ester. Succinic Acid.
(9) Tricarboxylic acids, containing two carboxyl groups attached to
the same C-atom, split off CO2 and yield the dibasic acid. Ethane
tricarboxylic acid yields succinic acid, and isobutane tricarboxylic
acid gives rise to unsym.-dimethyl succinic acid, etc.
Isomerism. — The possible structural isomers of the dicarboxylic
acids depend upon whether the two COOH groups are attached to
two different carbon atoms or to a single atom. Isomers of the
first two members of the series —
CO,H /COaH
(i) I and (2) CH2<
C02H XC02H
Ozs Uc Acid. M*k>tic Acid.
DERIVATIVES OF THE DICARBOXYLIC ACIDS 479
are not possible. For the third member two structural cases
exist :
CH2CO2H /CO2H
(3) | and CH8.CH<(
CHSC08H XC02H
Ethylene Dicarboxylic Acid, Etbylidene Dicarboxylic Acid,
Succinic Acid. Isosuccinic Acid.
PO TT
There are four possible isomers with the formula C,H,<CO2H>
etc. ; all are known :
CH8C02H CH2C02H CH(CO2H), CH,
(4) CHt CHC02H CH, C(C02H)2
CH2C02H CHS CH3 CH3
Glutaric Acid, Ord. Pyrotartaric Ethyl Malonic Dimethyl Malonic
»-PyroUrtaric Acid. Acid. Acid. Acid.
(5) The fifth member of the series, the acid C4H8(C02H)2j has nine
possible isomers ; all are known :
(a) Adipic acid— CO2H[CH2]4CO2H.
(b) a- and jS-Methyl glutaric acid.
(G) Sym.- and unsym.-dimethyl succinic acid, and ethyl succinic
acid.
(d) Propyl, isopropyl, and methyl ethyl malonic acids.
(6) There are twenty-four imaginable isomers of the sixth
member— the acids C5H10(C02H)2 (A. 292, 134).
Nomenclature (p. 42). — Whilst the names of the older dicarboxylic
acids — e.g. oxalic, malonic, succinic, etc. — recall the occurrence or
the methods of making these acids, the names of those acids which
have been synthetically prepared from malonic esters are derived from
malonic acid, e.g. methyl malonic acid, dimethyl malonic acid. The
names of the alkyl ethylene succinic acids, etc., have been derived from
ethylene succinic acid.
The " Geneva names " are deduced, like those for the mono-
car boxylic acids, from the corresponding hydrocarbons ; oxalic acid=
[Ethane-diacid] ; malonic acid=[Propane-diacid] ; ethylene succinic
acid=[Butane-diacid]. The bivalent residues linked to the two hy-
droxyls are called the radicals of the dicarboxylic acids — e.g. CO.CO,
oxalyl; CO.CH2.CO, malonyl, and CO.CH2.CH2.CO, succinyl. The
melting points of the normal dicarboxylic acids exhibit great regularity :
the members containing an even number of carbon atoms melt higher
than those with an odd number (Baeyer, p. 62).
Derivatives of the Dicarboxylic Acids — It has been indicated
in connection with the monocarboxylic acids (p. 233) what derivatives
of an acid can be obtained by a change in the carboxyl group. As
might well be expected, the derivatives of the dicarboxylic acids are
much more numerous, because not only the one group, but both
carboxyls can take part in the reaction. The heterocyclic derivatives
of the ethylene succinic and glutaric acid groups are particularly
noteworthy : they are the anhydrides (p. 476) and the acid imides,
e.g. succinimide, I ^>NH, and glutarimide, CH2<£**2;£°>NH. They
CHj.CO
have been previously mentioned.
48o ORGANIC CHEMISTRY
OXALIC ACID AND ITS DERIVATIVES
(1) Oxalic Acid, [Ethane-diacid], C204H2 (Acidum oxalicum),
m.p. anhydrous, 189°, hydrated, 101°, if rapidly heated (B. 21, 1961),
occurs in many plants, chiefly as potassium salt in the different varieties
of Oxalis and Rumex. The calcium salt is often found crystallized in
plant cells ; it constitutes the chief ingredient of certain calculi.
The acid may be prepared artificially (i) by oxidizing many carbon
compounds, such as sugar, starch, etc., with nitric acid.
Frequent mention has been made of its formation in the oxidation
of glycol, glyoxal, glycollic acid and glyoxylic acid (pp. 312, 477).
(2) From cellulose : by fusing sawdust with potassium hydroxide
in iron pans at 200-220°. The fused mass is extracted with water,
precipitated as calcium oxalate, and this is then decomposed by
sulphuric acid (technical method).
(3) It is formed synthetically by (a) rapidly heating sodium formate
above 440° (B. 15, 4507) : the addition of sodium hydroxide, carbonates
or oxalates enable the reaction to take place at 360°, and more com-
pletely (C. 1903, II. 777 ; 1905, II. 367) :
HCOONa COONa
= j +Ht;
HCOONa COONa
by (b) oxidizing formic acid with nitric acid (B. 17, 9).
(4) By conducting carbon dioxide over metallic sodium heated to
35o-36o0 (A. 146, 140) :
2CO2+Na2=C2O4Na2.
CO2 and potassium hydride yield a mixture of potassium formate
(p. 237) and oxalate.
(5) Upon treating the nitriles, cyanocarbonic ester and dicyanogen,
with hydrochloric acid or water respectively :
CN CO2H CN
> I < I •
CO2C2H6 CO2H CN
History. — At the beginning of the seventeenth century salt of sorrel was
known, and was considered to be a variety of argol. Wiegleb (1778) recognized
the peculiarity of the acid contained in it. Scheele had obtained the free oxalic
acid as early as 1776 by oxidizing sugar with nitric acid, and showed in 1784
that it was identical with the acid of the salt of sorrel. Gay-Lussac (1829) dis-
covered that oxalic acid was formed by fusing cellulose, sawdust, sugar, etc.,
with potassium hydroxide. This process was introduced into practical manu-
facture in 1856 by Dale.
Constitution. — Free oxalic acid crystallizes with two molecules of
water. The crystallized acid is probably ortho-oxalic acid, C(OH)3.-
C(OH)3 (p. 235). Ortho-esters of the acid C2(OR')6 are not known,
but esters do exist, which are derived from the non-isolated half -ortho-
oxalic acid, C(OH)3.CO2H.
Properties and Reactions. — Oxalic acid crystallizes in monoclinic
prisms, which effloresce at 20° in dry air. Large quantities of the acid,
introduced into the system, are poisonous. It is soluble in 9 parts
OXALIC ACID 481
of water at ordinary temperatures, and fairly easily in alcohol, and
with difficulty in ether (C. 1897, I. 539). Anhydrous oxalic acid
crystallizes from concentrated sulphuric and nitric acid (B. 27, R. 80),
and can be employed as a means of bringing about condensation,
on account of its power of abstracting the elements of water from the
substance to be condensed (B. 17, 1078). When carefully heated to
150° the anhydrous acid sublimes undecomposed. (i) Rapidly heated
it decomposes into formic acid and carbon dioxide, and also into CO2,
CO and water : «,
C2H204=CH2O2+ CO, ; C,H2O4=CO2-fCO+H2O.
(2) An aqueous oxalic acid solution under the influence of light and air
decomposes into CO2, H2O, and in the presence of sufficient oxygen, H2O2 (B.
27, R. 496).
(3) Oxalic acid decomposes into carbonate and hydrogen by fusion
with alkalis or soda lime :
C204K2+2KOH=2KaC03+H2.
(4) Heated with concentrated sulphuric acid it yields carbon
monoxide, dioxide and water.
(5) Nascent hydrogen converts it first into glyoxyllic acid (p. 400)
and then into glycollic acid (p. 362).
(6) Concentrated nitric acid slowly oxidizes oxalic acid to CO2 and
water. However, potassium permanganate in acid solution rapidly
oxidizes it, a reaction which is used in volumetric analysis.
Persulphates in acid solution and in presence of silver salts oxidize
oxalic acid very energetically. This reaction constitutes a quantitative
method for determining the active oxygen of persulphates (B. 38, 3963).
A solution of mercuric chloride and ammonium oxalate rapidly
decomposes, in the light and in absence of oxygen, into carbon dioxide
and calomel (B. 38, 2602).
(7) PC15 changes oxalic acid into POC13, C02, CO, and 2HC1.
It has also been possible to replace 2C1 by O in certain organic di-
chlorides by using anhydrous oxalic acid (p. 272). SbCl5, however,
and oxalic acid yield the compound (COOSbCl4)2 (A. 239, 285 ; 253,
112 ; B. 35, 1119).
The oxalates, excepting those with the alkali metals, are almost insoluble in
water.
Di-potassium Oxalate, C2O4K2+H2O. Mono-potassium Oxalate, C2O4HK, dis-
solves with more difficulty than the neutral salt, and occurs in the j uices of plants,
such as Oxalis and Rumex. Potassium Peroxalate, C2O4KH.C2O4H2+2H2O.
Di-ammonium Oxalate, C2O4(NH4)2-t-H3O, consists of shining, rhombic
prisms, which occur in laevo- and dextro-/z0mt hedral crystals (B. 18, 1394; C. 1905,
II. 885). Calcium Oxalate, C2O4Ca+H2O, is- insoluble in acetic acid, and serves
for the detection of calcium and of oxalic acid, both of which are determined
quantitatively in this form. The silver salt, C2O4Ag2, explodes when quickly
heated.
Oxalic acid yields crystalline compounds with substances containing oxygen,
such as cinnamic aldehyde, cineol, and dimethyl pyrone (Vol. II.) (B. 35, 1211).
Trimercuric Acetic Acid, HOHg(Hg2O)C.COOH, and Mercarbide, HOHg-
(Hg2O)C.C(Hg2O)HgOH (comp. p. 116), are derivatives of oxalic acid. They
are obtained when acetic acid or alcohol is heated with HgO in the presence
of alkalis. They consist of white powders of basic character. Mercarbide is
very stable towards reagents, but explodes violently when heated above 200°
(B. 33, 1328 ; 36, 3707 ; 38, 3654).
Oxalic Esters. — The acid and neutral esters of oxalic acid are formed
VOL. I. 2 I
482 ORGANIC CHEMISTRY
simultaneously when anhydrous oxalic acid is heated with alcohols. They are
separated by distillation under reduced pressure (Anschutz, A. 254, i).
CO,CaH8
Oxalic Mono-ethyl Ester, | , b.p.lt 117° ; D20=i-2i75. Oxalic n.-
COaH
Propyl Ester, COa.C3H7.CO,H, b.p.lt 118°. Preserved in sealed tubes, the
alkyl oxalic acids decompose into anhydrous oxalic acid and the neutral
esters. Distilled at the ordinary temperature, they break down mainly into
oxalic ester, COa, CO and H2O, and in part to COa and formic esters.
Oxalic Methyl Ester, C2O<(CH,)a, m.p. 54*. b.p. 153°.
Oxalic Ethyl Ester, b.p. 186*, is formed upon heating oxomalonic ester
(B. 27, 1304). See p. 427 for its conversion into carbonic ester. Oxalic ester,
under the influence of sodium ethoxide, condenses with acetic ester to form
oxalacetic ester, CO,C2H8.CO.CHt.COaC,H8, and with acetone to acetone oxalic
ester comp. (chelidonic acid). Zinc and alkyl iodides convert the oxalic ester into
dialkyl oxalic esters (p. 358).
Oxalic ester unites with hydroferrocyanic acid to form a well-crystallizing
compound (COOC,H,)2.H4Fe(CN), (B. 34, 2692). With SbCl, ethyl oxalate
forms CLSbCjHiOCO.COOCaH^SbClJ, (B. 35, 1120).
COOCH,
Ethylene Oxalic Ester, \ \ , m.p. 143°, b.p., 197* (B- 27, 2941).
Half-ortho-oxalio Acid Derivatives. — Dichloroxalic Esters : When PC1B acts
on the neutral oxalic esters, one of the doubly-linked oxygen atoms is replaced
by 201 atoms :
COOC,H8 CClaOC,H,
I +PC1,= | +POC1,.
COOCaH5 COOCaH. «
These products are called dichloroxalic esters (B. 28, 61, note). When
fractionated under greatly reduced pressure, they can be separated from unaltered
oxalic ester. Distilled at the ordinary pressure, these esters decompose into
alkyl chlorides and alkyl oxalic acid chlorides (see below).
Dichloroxalic Dimethyl Ester, CCla(OCHs).COaCHs, b.p.ia 72°. 0,0=1-3591.
Dichloroxalic Diethyl Ester, b.p. 1 0 85°. Dichloroxalic Di-n-Propyl Ester, b.p. j 0 1 07°.
Ethyl Dichloroxalic Chloride, COCl.CClt.OCaH8, b.p. 140°, results from tri-
chlorovinyl ethyl ether, CClt: CClOCtH,, by absorption of oxygen (A. 308, 324).
Half -ortho-oxalic Esters are produced by the interaction of dichloroxalic
esters with sodium alcoholates in ether :
COtC1H».CCl1OCfH5-f2CaH5ONa=COaC1H,.C(OCaH5),+2NaCl.
Tetramethyl Oxalic Ester, C(OCHS),.COOCH8, b.p.lt 76°; 0—1-1312. Tetraethyl
Oxalic Ester, b.p.lt 98° (A. 254, 31).
The anhydride of oxalic acid is not known. In attempting to prepare it
CO, and CO are produced. However, the chlorides of the alkyl oxalic acids,
and probably oxalyl chloride, are known.
Chlorides of Alkyl Oxalic Acid are obtained by the action of POC1, on potas-
sium alkyl oxalates, and of SOC1, on alkyl oxalic acids (B. 37, 3678). It is
most practically prepared by boiling dichloroxalic esters under the ordinary
pressure until the evolution of the alkyl chloride ceases (A. 254, 26). They
show the reactions of an acid chloride (p. 269). With benzene hydrocarbons
and AlaCl, they yield phenyl glyoxylic esters and their homologues (B. 14,
1689 ; 29, R. 511, 546 ; C. 1897, I. 407).
are liquids with a penetrating odour. Oxalic Mono-ethyl Ester Anhydride,
(CaH6OCO.CO)aO, b.p.ieo 135°, is prepared by heating ethyl oxalic chloride and
sodium acetate together, and fractionating the product of reaction (C. 1900, II. 174).
Oxalyl Chloride, CtOaCl, (?), b.p. 70°. It has not been obtained free from
POC1S. It is said to be formed when three molecules of phosphorus penta-
chloride act on (COOCjH,), (B. 25, R. no).
AMIDES OF OXALIC ACID 483
AMIDES OF OXALIC ACID
Oxalic acid yields two amides : oxamic acid, corresponding with the
mono-ethyl oxalic ester, and oxamide, corresponding with oxalic diethyl
ester. Oximide can be included with these :
COOC.Hr CO.NH. COOC2H6 CONH, CCk
I III >NH(?).
COOH COOH COOC2H5 CONH, CCK
Ethyl Oxalic Oxamic Oxalic Oxamide. Oximide.
Acid. Acid. Ester.
Oxamic Acid, C,Oa<QHt> m.p. 210° with decomposition. Its ammonium
salt (Balard, 1842) is produced (i) by heating ammonium hydrogen oxalate ;
(2) from oxamide ; (and (3) by boiling oxamic acid esters with ammonia (B. 19,
3229 ; 22, 1569). Hydrochloric acid precipitates oxamic acid from its ammonium
salt as a difficultly soluble crystalline powder.
Its esters result from the action of alcoholic or dry ammonia on the esters
of oxalic acid :
Ethyl Oxamic Ester, Oxamethane, CONH2.COOC2H5, m.p. 114° (Boullay
and Dumas, 1828). The behaviour of oxamethane towards PC16 is important
theoretically, because at first it yields ethyl oxamino-chloride, oxamethane chloride,
a derivative of half-ortho-oxalic acid (comp. Dichloroxalic Ester, p. 482). This
splits off a molecule of HC1 and becomes ethyl oximido-chloride, and by the loss
of a second molecule of HC1 passes into cyanocarbonic ester (p. 484) '(Wallach,
A. 184, i):
COOCjH, PCI. COOCaH§ -HCI^ COOC2H5 -HCI ^ COOCjH.
CONH2 CC12NH? CC1=NH C^N
Oxamethane. Ethyl Oxamino- Ethyl Oximido- Cyanocarbonic
chloride. chloride. Ester.
Oxamine Trimethyl Ortho-Ester, CONH2.C(OCH3)3, m.p. 115°, is formed on
heating half-ortho-oxalic methyl ester with anhydrous methyl alcoholic ammonia.
Methyl Oxamic Acid, CONH(CH8).CO2H, m.p. 146°.
Ethyl Oxamic Acid, CONH(C2H6)CO2H, m.p. 120°.
Diethyl Oxamic Acid, Diethyl Oxamethane, CON(C2H5)2CO2H, b.p. 254°, is
produced by the action of diethylamine on oxalic esters. It regenerates
diethylamine on being distilled with potassium hydroxide. A method for separat-
ing the amines (p. 161) is based on this behaviour.
Oxanilic Acid (see Vol. II.).
CCK
'\
C
PCltO (B. 19, 3229). The molecule is probably a double one.
Oxalimide, \ }NH (?), is obtained from oxamic acid by the aid of PCL or
~CK
Oxamide, C202(NH2)2, separates as a white, crystalline powder,
when neutral oxalic ester is shaken with aqueous ammonia (1817,
Bauhof). It is insoluble in water and alcohol. It is also formed on
heating ammonium oxalate (1830, Dumas ; 1834, Liebig) ; and when
water and a trace of aldehyde act on cyanogen, C2N2 ; or by the
direct union of hydrocyanic acid and hydrogen peroxide :
2HNC +H2O2 =C202N2H4.
Oxamide is partiallysublimedwhenheated,thegreaterpart, however,
being decomposed. When heated to 200° with water, it is converted
into ammonium oxalate. P2O5 converts it into dicyanogen ; concen-
trated sulphuric acid, into ammonium sulphate, CO2 and CO (B. 39, 57).
Alkyl oxamides are produced by the action of the primary amines
on the oxalyl esters.
484 ORGANIC CHEMISTRY
sym.-Dimethyl Oxamide, (CONHCH3)2, m.p. 210°.
sym.-Diethyl Oxamide, (CONC2H6)2, m.p. 179°.
Tetramethyl Oxamide, [CON(CH3)~2]2, m.p. 80°, is obtained from dimethyl
urea chloride by the action of sodium (B. 28, R. 234).
Oxanilide (Vol. II.).
PC16 converts these alkyl oxamides into amide chlorides, which lose 3HC1
and pass into glyoxaline derivatives (Wallach, A. 184, 33 ; Japp, B. 15, 2420) :
thus diethyl oxamide yields chloroxalomethyline, and diethyl oximide yields chloroxai-
ethyline :
CONHCH5 aPCl. CC12NHCH8 _2HC1 CC1:NCH8 -HC1 CH— N(CH3K
I > I > I > II _^CH
CONHCH3 CC12NHCH8 CClrNCH, CC1— N^
Dimethyl Dimethyl Dimethyl Chloroxalmethylin.
Oxamide. Oxamide Oximide
Tetrachloride. Dichloride.
Oxamidoacetic Acid, Amidoxolyl Glycocoll, NH2CO.CONH.CH2CO2H, m.p.
224-228° with decomposition, and Oxalyl Diglycocoll, Oxamidodiacetic Acid,
CO2HCH2.NHCOCONH.CH2CO2H, are formed 'from oxamethane and cfcalic
ester and glycocoll respectively (B. 30, 580).
Diethyl Dinitro-ox amide, ^^| >N.CO.CO.N<^« , m.p. 35°, is decomposed
by dilute sulphuric acid to form ethyl nitramine (C. 1898, I. 373).
Hydrazides and Hydroxyamides of Oxalic Acid, Semi-ox amazide, Oxaminic
Hydrazide, NH2COCONH.NH2, m.p. 220° with decomposition, is prepared
from oxamethane and hydrazine. Similarly to semicarbazide, it gives condensa-
tion products with aldehydes and ketones (B. 30, 585).
Oxalic Hydrazide, NH2.NHCOCO.NHNH2, decomposes at about 235°, and
turns brown. It is formed when hydrazine hydrate acts on oxalic ester. It
unites with acetoacetic ester to form bis-acetoacetic ester oxalhydrazone,
(C6H1002) : NNHCOCONHN:(C,H1002) (B. 40, 711).
The reaction products of diazoacetic acid (p. 405) can be looked on as being
cyclic hydrazine derivatives of oxalic acid ; they yield hydrazine and oxalic
acids when hydrolyzed.
Hydroxyl Oxamide, NH2COCONH.OH, m.p. 159°, is formed from oxamethane
and hydroxylamine.
Acetoxyl Oxamide, NH2COCONH.OCOCH8, m.p. 173°, when heated with
acetic anhydride to 110° is decomposed into cyanuric acid (p. 463) and acetic
acid (A. 288, 314; comp. C. 1901, II. 210/402). Amidoxime Oxalic Acid,
HOOC.C(NOH)NHa (A. 321, 357).
NITRILES OF OXALIC ACID
Two nitriles correspond with each dicarboxylic acid : a nitrilic acid,
or a half-nitrile, and a dinitrile. The nitrilic acid of oxalic acid is
cyanocarbonic, cyanoformic, or oxalonitrilic acid, and it is only known
in its esters. Dicyanogen is the dinitrile of oxalic acid. The connec-
tion between these nitriles and oxalic acid is shown by their formation
from the oxamic esters and oxamide through the elimination of water,
and their conversion into oxalic acid by the absorption of water and
the loss of ammonia :
COOC2HB -H20 COOC,HS CONH, -«H2O CN
CONH2 CN CONHa CN
Oxamethane. Cyanocarbonic Ethyl Ester. Oxamide. Dicyanogen.
Cyanocarbonic Esters, Cyanoformic Esters, Nitrilo-oxalic Esters, are produced
during the distillation of oxamic esters with P2O6 or PCI (p. 483), as well as
from cyanimidocarbonic ether. Cyanocarbonic Methyl Ester, CN.CO2CH,,
b.p. 100°. Cyanocarbonic Ethyl Ester, b.p. 115°. These are liquids with a
DICYANOGEN 485
penetrating odour. They are insoluble in water, which slowly decomposes
them into CO2, hydrocyanic acid, and alcohols. Zinc and hydrochloric acid
convert them into glycocoll (p. 385). Concentrated hydrochloric acid breaks
them down into oxalic acid, ammonium chloride, and alcohols. Bromine or
gaseous HC1 at 100° converts the ethyl ester into the polymeric cyanuric tri-
carboxylic esters (p. 465).
Cyanimidocarbonic Acid Ethers, Oxalic Nitrik Imido Ether, CN.C( : NH)OCaH8,
b.p.ao 50°, is prepared from cyanogen chloride or bromide and water, alcohol,
and potassium cyanide ; also from potassium cyanide, water, and ethyl hypo-
chlorite (p. 141), when the following intermediate compounds must be assumed :
KN:COC2H5 KNC KN:C.OC2H6 H2O HN:COC2H5
I
Cl
KN:C+C2H6OC1 > \ > \ >
C1C:NK CN
This reaction points to K.N:C being the formula for potassium cyanide,
since it is hard to represent it with the formula KCN (A. 287, 273). Cyanimido-
carbonic acid ether forms a yellow, sweet oil, possessing, at the same time, a
pungent odour. Concentrated hydrochloric acid converts it into ammonium
chloride and cyanocarbonic acid ester.
Chlorethyl Imidoformyl Cyanide, Oxalic Nitrile Ethyl Imidochloride,
CN.C( : NC2H5)C1, b.p. 126°, is prepared from cyanogen chloride and ethyl
isocyanide (A. 287, 302).
Cyanorthoformic Ester, Triethoxyacelonitrile, Ortho-oxalonilrilic Ethyl Ester,
CN.C(9C2H6)3, b.p. 160° (A. 229, 178).
Trinitro-acetonitrile, CNC(NO2)3, m.p. 41 -5°, explodes at 220° (see fulminuric
acid, p. 250).
Dicyanogen, Oxalonitrile, [Ethane Dinitrile], CN.CN, b.p. —21°,
D=0'866 (liquid), is present in small quantity in the gases of the blast
furnace. It was obtained in 1815 by Gay-Lussac by the ignition of
mercury cyanide. The change proceeds more readily by the addition
of mercuric chloride :
Hg(CN)t=C2N2+Hg. Hg(CN)a+HgCla=CaNa+HgaCla.
Silver and gold cyanides behave similarly. Dicyanogen is most readily
prepared from potassium cyanide, by adding gradually a concentrated aqueous
solution of i part KNC to 2 parts cupric sulphate in 4 parts of water, and then
heating. At first a yellow precipitate of copper cyanide, Cu(CN)2, is produced,
but it immediately breaks up into cyanogen gas and cuprous cyanide, CuCN
(B. 18, R. 321):
2CuSOi+4KNC=Cu2(CN)2+(CN)a+2K2SO4.
Its preparation by heating ammonium oxalate, and from oxamide
and P-2O5, is of theoretical interest.
Properties and Reactions. — Cyanogen is a colourless, peculiar-
smelling, poisonous gas. It may be condensed to a mobile liquid at a
temperature of —25°, or by a pressure of five atmospheres at ordinary
temperatures ; at —34° it forms a crystalline mass. It burns with a
bluish, purple-mantled, flame. Water dissolves 4 volumes and alcohol
23 volumes of the gas.
On standing the solutions become dark and break down into ammonium
oxalate and formate, hydrogen cyanide and urea, and at the same time a brown
body, the so-called azulmic acid, C4H6N6O, separates. With aqueous potassium
hydroxide cyanogen yields potassium cyanide and isocyanate. In these reactions
the molecule breaks down, and if a slight quantity of aldehyde be present in
the aqueous solution, only oxamide results. Oxalic acid is produced in the
presence of mineral acids, CaN2+4H1O=CaO4Ha-f-2NH8. When heated with
486 ORGANIC CHEMISTRY
concentrated hydriodic acid it is converted into glycocoll (p. 385). Cyanogen
unites with acetyl acetone (p. 350), with sodium acetoacetic ester (p. 418), and
with sodium malonic ester (p. 488).
Paracyanogen. — On heating mercuric cyanide there remains a dark substance,
paracyanogen, a polymeric modification, (C2N2)w. Strong ignition converts it
again into cyanogen. It yields potassium cyanate with potassium hydroxide.
Thioamides of Oxalic Acid. Rubeanic Acid, Dithio-ox amide, CSNH2.CSNH2,
and Flaveanic Acid, Cyanothioformamide, CS.NH2.CN, m.p. 87-89°, with de-
composition, are formed when H 2S and cyanogen interact. They can be separated
by means of chloroform, in which rubeanic acid is soluble with difficulty,
and which deposits the flaveanic acid in the form of yellow, transparent,
flat needles (A. 254, 262). Rubeanic acid forms yellowish-red crystals. Primary
bases cause the replacement of the amido-groups by alkyl amido-groups (A. 262,
354). Aldehydes unite with rubeanic acid, with elimination of water (B. 24,
1017). Chrysean, C4H6N3S2, is prepared from KNC and HaS, or thioformamide,
HCSNH., and probably possesses the formula || \C.CSNH2 (B. 36,
H2NC - N'
3546). Thio-oxalic Acid, HSCO.COSH (C. 1903, I. 816).
Diamido-oxalic Ethers result from the action of ammonia on dichloroxalic
esters, but have not yet been obtained in a pure condition. Aniline and dichlor-
oxalic ether in cold ethereal solution, yield Dianilido-oxalic Ether, CO2C2H6C-
(NHC,jH,)2OC2H5, a thick liquid, soluble in ether. At o° hydrochloric acid
precipitates from this ethereal solution the hydrochloride, CO2C2H6C(NHC0H5-
HC1)2OC2H6. Mixed diamido-ethers can be obtained by allowing anhydrous
ammonia gas to act on a cooled, ethereal solution of monophenylimido-oxalic
acid dimethyl ether. In this way Amino-anilido-oxalic Methyl Ester,
CO2CH3.C(NH2)(NHC6H6)OCH3> is obtained, m.p. 215°.
Imido-oxalic Ethers : Mono-imido-oxalic Ether, CO2C2H5.C( : NH)OC2H6,
b.p.ls 73°, results from the action of a calculated amount of ^ w-hydrochloric
acid on di-imido-oxalic acid (A. 288, 289). Phenylimido-oxalic Methyl Ether,
COaCH3.C(=N.C8H6)OCHa.
Di-imido-oxalic Ether, C2H6O.(NH)C— C(NH).OC2H6, m.p. 25°, b.p. 170°.
Its hydrochloride is obtained on conducting HC1 into an alcoholic solution of
cyanogen (B. 11, 1418) (comp. p. 281).
Oxalamidine, NH2(NH)C— C(NH)NH2, results from the action of alcoholic
ammonia on the hydrochloride of oximido-ether (B. 16, 1655).
HN:C.NHNH2
Carbohydrazidine, Oxalodi-imide Dihydrazide, , forms white,
NH:C.NHNH2
flat needles, which assume a reddish-brown colour on heating and do not melt
at 250°. It results from the union of cyanogen with hydrazine. Dibenzal
Carbohydrazidine, m.p. 218° (J. pr. Ch. [2] 50, 253).
Oxalodihydroxamic Acid, [C : (NOH)OH]2, m.p. 165°, results from oxalic ester
and hydroxylamine (B. 27, 709, 1105).
Oxalodiamidoxime, [C(N.OH)NH2]2, m.p. 196°, with decomposition. It is
formed when NHaOH acts (i) on cyanogen (B. 22, 1931), (2) on cyananiline
(B. 24, 801), (3) on hydrorubeanic acid (B. 22, 2306); dibenzoyl derivative,
m.p. 222° (B. 27, R. 736).
Chloroximido-acetic Ester, Ethoxalo-oxime Chloride, CO2C2H5.C( : NOH)C1,
m.p. 80°, is obtained from chloracetoacetic ester by means of fuming nitric acid ;
and when concentrated hydrochloric acid acts on nitrolacetic ester (B. 28,
1217 ; 39, 784). Similarly, chloracetoacetic ester and diazobenzene chloride yield
chlorophenylhydrazido-acetic ester, oxalic ester, phenylhydrazido-chloride, CO2R.C-
(:NNHC6H5)C1 (C. 1902, II. 187).
Nitrolacetic Ester, Ethoxalonitrolic Acid, CO2C2H6.C(:NOH).NO2, m.p. 69°,
is prepared from isonitroso-acetoacetic ester and nitric acid of sp.gr. 1-2 (B.
28, 1217).
Formaxyl Carboxylic Acid, COjH.C1 , m.p. 162°, when rapidly
heated, is produced when its ester is saponified. The ester results from the
action of diazobenzene chloride (i) on the hydrazone of mesoxalic ester,
(2) on sodium malonic ester, and (3) on acetoacetic ester, whilst oxalic acid
MALONIC ACID 487
breaks down into formic acid and CO 2, fonnazyl carboxylic acid decomposes into
formazyl hydride (p. 244) and CO2 (B. 25, 3175, 3201).
Ureides of Oxalic Acid, Parabanic acid, and Oxaluric acid will be considered
together with the derivatives of uric acid (q.v.).
THE MALONIC ACID GROUP
Malonic Acid [Propane Diacid], CH2(CO2H)2, m.p. 132°, occurs
as its calcium salt in sugar-beets, (i) The acid was discovered in 1858,
by Dessaignes, on oxidizing malic acid, CO2H.CH(OH).CH2CO2H,
with potassium bichromate (hence the name, from malum, apple), and
quercitol with potassium permanganate (B. 29, 1764). It is also
produced (2) in the oxidation of hydracrylic acid, and (3) of propylene
and allylene by means of KMnO4. (4) Kolbe and Hugo Miiller obtained
it almost simultaneously (1864) by the conversion of chloracetic acid
into cyanacetic acid, the nitrile acid of malonic acid, and then saponi-
fying the latter with potassium hydroxide. (5) By the decomposition
of barbituric acid or its malonyl urea (q.v.). (6) Malonic ester and
CO are formed in the distillation of oxalacetic ester (q.v.} under the
ordinary pressure (B. 27, 795).
Preparation. — One hundred grams of chloracetic acid, dissolved in 200 grams
of water, are neutralized with sodium carbonate (no grams), and to this 75
grams of pure, powdered potassium cyanide are added, and the whole carefully
heated, after solution, upon a water-bath. The cyanide produced is hydrolyzed
either by concentrated hydrochloric acid or potassium hydroxide (B. 13, 1358 ;
A. 204, 225 ; C. 1897, I. 282). To obtain the malonic ester directly, the cyanide
solution is evaporated, the residue covered with absolute alcohol, and HC1 gas
led into it (A. 218, 131), or it is treated with sulphuric acid and alcohol (C. 1897,
I. 282).
Properties. — Malonic acid crystallizes in triclinic plates. It is
easily soluble in water and alcohol. Above its melting point it de-
composes into acetic acid and carbon dioxide. Bromine in aqueous
solution converts it into tribromacetic acid and CO2, whilst iodic acid
changes it to di- and tri-iodoacetic acid (p. 489) and CO2.
Salts.— Barium salt, (C3H2O4)Ba+2H2O : calcium salt, C3H2O4Ca-
+ 2H20, dissolves with difficulty in cold water : silver salt, C^L2O^Ag2,
is a white, crystalline compound.
Ester. Malonic Mono-ethyl Ester, b.p.ai 147°, is decomposed at higher
temperatures into CO2, acetic ester, acetic acid, and diethyl malonate : potas-
sium salt is prepared from the neutral ester and one molecule of alcoholic potas-
sium hydroxide. Electrolysis of this produces succinic ethylene ester (pp. 478,
492) (comp. C. 1900, II. 171 ; 1905, II. 30, where also are found ester-acids of
alkyl malonic acid).
The neutral malonic esters are made by treating potassium cyan-
acetate or malonic acid with alcohols and hydrochloric acid. These
compounds are of the first importance in the synthesis of the poly-
carboxylic acids, because of the replaceability of the hydrogen atoms
of the CH2-group by sodium.
History. — This property was first observed in 1874 by van't Hoff, Sr. (B. 7,
1383), and the possibility of obtaining the malonic acid homologues, by means
of it, was indicated. The comprehensive, exhaustive experiments begun in
ORGANIC CHEMISTRY
1879 by Conrad first demonstrated that malonic esters were almost as valuable
as the acetoacetic esters in carrying out certain synthetic reactions (pp. 412, 415)
(A. 204, 121).
The methyl ester, CH2(CO2CH3)2, b.p. 181° ; ethyl ester, b.p. 198° ; D18 ro68.
By the action of sodium ethoxide on it the Na-compounds, CHNa(CO2C2H5)2
(p. 490) and CNa2(CO2C2H5)2 (?), result. The malonic esters possess the character-
istics of weak acids (B. 17, 2783 ; 24, 2889 ; 32, 1876 ; 86,268). Aluminium
Malonic Ester, A1[CH(CO2C2H5)]3, m.p. 95°, is formed by the action of aluminium
amalgam on malonic ester (C. 1900, I. 12).
Reactions of Malonic Ester and its Salts. — Iodine converts both sodium
malonic esters into ethane and ethylene tetracarboxylic esters (q.v.). Sodium
malonic ester, when electrolyzed, yields ethane tetracarboxylic ester (B. 28,
R. 450). Alkyl halides convert the sodium malonic esters into esters of malonic
acid homologues (B. 28, 2616). When sodium acts on malonic ester at 70-90°,
alcohol is given off, and there is formed the di-sodium compound of acetone
tricarboxylic ester. This substance acted on by sodium malonic ester at 145°, loses
two molecules of alcohol, whereby tri-sodium phloroglucinol carboxylic ester is
formed (Vol. II.) (B. 32, 1272) :
C02CaH6CHNa.CNa(COtCaH6)2+CHNa(CO2C2H6)2
=C608Na3(C02C2H6)3+2C2H6OH.
Malonic ester condenses with aldehydes under the influence of acetic anhy-
dride, hydrochloric acid, sodium ethoxide, or small quantities of ammonia
diethylamine and piperidine. In the last case an intermediate product is formed
— alkylidene piperidine, which is converted by malonic ester into alkylidene bis-
malonic ester (B. 31, 2585).
The free malonic acid also condenses with aldehydes and with some ketones,
when heated with acetic acid, acetic anhydride, or pyridine ; water and COa are
split off and unsaturated carboxylic acids are formed (pp. 290, 305).
a/J-dlefine aldehydes, a/?-olefine ketones, and aj3-olefine carboxylic esters
unite with sodium malonic ester, a synthesis in which the NaC(CO2R)2 residue
joins with the £ -carbon atom, and the H-atom with the a-carbon atom. The
aldehyde groups of the olefme aldehydes under these conditions unite also with
two molecules of malonic ester (comp. A. 360, 323).
Cyanogen combines with malonic ester in presence of a little sodium ethoxide
to form cyanimido-di-isosuccinic ester, NC.C(NH)CH(CO2C2H5)2, and di-imido-
oxalyl dimalonic ester, (C2H6OCO)2CHC(NH).C(NH)CH(CO2C2H6)2.
Diazobenzene chloride and malonic ester yield mesoxalic ester phenylhydrazone
(q.v.).
Malonic Anhydride, CH2<Sp>O, is not known (comp. p. 476).
Carbon Suboxide, Dioxoallene, Carbon Dicarbonyl, C8O2, m.p. — 108°, b.p. +7°,
D°o=i*H37, is produced when malonic ester, or, better, malonic acid, is heated with
PS^S (0- Diets, B. 41, 82). It may be looked on as being a double malonic anhy-
dride. In behaviour it resembles most nearly the ketenes (pp. 474, 475), and
is therefore to be looked on as carbon dicarbonyl or dioxoallene: CO=C=CO;
it may also be considered as being f}-hydroxypropiolic lactone, co^0 (B- 41»
925). Carbon suboxide polymerizes at ordinary temperatures to a dark-red solid
mass. Water regenerates malonic acid ; ammonia and aniline produce malon-
amide and maloanilide. Hydrochloric acid forms malonyl chloride ; bromine
produces dibromomalonyl bromide which reforms carbon suboxide by the action
of zinc in ether (B. 41, 906) :
-2H2O 4Br
CH,(COOH)2 < >CO=C=CO: CQ=C=CO< > BrCOCBr,COBr.
•faHjO aZn
Chlorides of Malonic Acid.
Malonyl Chloride Monoethyl Ester, CO2C2H6.CH2COC1, b.p.18 69°, is prepared
from ethyl potassium malonate and PC18 ; or malonic ester and SOC12 (B. 25,
1504 ; C. 1905, II. 30 ; also for homologous chloride esters).
Malonyl Chloride, CHt(COCl)a, b.p.a? 58°, is formed by the action of SOC1,
ALKYL MALONIC ACIDS 489
On malonic acid, together with the monochloride, HOCOCH2COC1, m.p. 65°,
with decomposition (B. 41, 2208).
Malonamide Monoethyl Ester, CO2C2H6.CH2CONH4, m.p. 50°, is formed when
malonic ester imido-ether hydrochloride (see below) is heated ; also from malonyl
chloride mono-ester and ammonia (B. 28, 479 ; C. 1905, II. 30).
Malonamide, CH2(CONH2)2, m.p.ijo0. Malonic Hydrazide, CHa(CONH.NH2)t,
m.p. 154°, reacts with aldehydes and ketones with loss of water (B. 39, 3372 ;
41,64i).
Nitriles of Malonic Acid: Cynacetic Acid, Nitrihmalonic Acid, half nitrile of
malonic acid, CN.CH2.CO2H (p. 487), m.p. 70° (B. 27, R. 262), dissolves very
readily in water, and at about 165° breaks down into CO2 and acetonitrile (p.
280). Cyanacetic Ethyl Ester, CN'.CH2.CO2C2H6, b.p. 207° (for preparation, see
C. 1905, I. 150), forms sodium derivatives like malonic ester (C. 1900, II. 38),
by means of which the hydrogen of the CH2-groups can be replaced by alkyls
(B. 20, R. 477) and acid radicals (B. 21, R. 353). Cyanacetamide, CN.CH,.CONH2,
is prepared from the ester and ammonia, m.p. 118°. Cyanacefyl Hydrazide,
CNCH2CO.NHNH2, m.p. 114° (J. pr. Ch. [2] 51, 186).
Cyanacetic ester unites with alcohol and hydrochloric acid to form malonic
ester imido-ether hydrochloride, C2H6OCO.CH2C(:NH.HC1)OC2H5, which, on
digestion with alcohol, yields the half ortho-ester of acid malonic ester (comp.
Ortho-ester, p. 284). The latter loses alcohol and passes into the acetal of car-
bomethane carboxylic ester, called Diethoxyacrylic Ester, (C2H6O)2C=CH.CO2C2H5,
b.p.12 128°. This substance, when shaken with water, is converted into malonic
ester ; bromine produces an oily dibromide, and with an increased quantity,
dibromo malonic ester (B. 40, 3358).
Malononitrile, Methylene Cyanide, CH2(CN)2, m.p. 30°, b.p. 218°, is obtained
by distilling cyanacetamide with P2O5 (C. 1897, I. 32). It is soluble in water.
Ammoniacal silver nitrate precipitates CAg2(CN2) from the aqueous solution
(B. 19, R. 485). Hydrazine and malononitrile yield Diamidopyrazole,
C3N2H2(NH2)2 (B. 27, 690) (see also cyanoform). Methenylamidoxime Acetic
Acid, NH2(HON) : C.CH2CO2H, m.p. 144° (B. 27, R. 261 ; A. 321, 357). Nitrilo-
malonimidoxime, Cyanethenylamidoxime, CN.CH2C(:NOH)NH2, m.p. 124-127°.
Malondihydroxamic Acid, CH2[C( : NOH)OH]2, m.p. 154° (B. 27, 803). Malon-
diamidoxime, CH2.[C( : N.OH)NH2]2, m.p. 163-167° (B. 29, 1168).
The urefdes of malonic acid and cyanacetic acid will be treated later in con-
nection with uric acid (q.v.).
Halogen-substituted Malonic Acids are formed by the action of chlorine or
sulphuryl chloride, bromine or iodine and iodic acid on malonic acid or its esters.
Such malonic and alkyl malonic acids (see below) easily part with CO2 and form
a-halogen fatty acids, some of which are conveniently prepared in this way (B.
35, 1374 1813; 39, 351). Monochloromalonic Acid, CHC1(COOH)2 ; ethyl ester,
b.p. 222°. Monobromomalonic Acid, CHBr(COOH)2, b.p. 113°, with decomposi-
tion ; methyl ester, b.p. 215-225°. Dichloromalonic Acid, CC12(COOH)2 ; ethyl
ester, b.p. 231-234° ; amide, m.p. 203°. Dibromomalonic Acid, CBr2(COOH)2,
m.p. 147°, with decomposition ; dimethyl ester, m.p. 64°. Dibromomalonic
Nitrile, m.p. 65° (C. 1897, I- 32)- Dibromomalonyl Bromide, b.p.,, 92° (see p.
488, Carbon Suboxide). Dibromomalonamide, m.p. 200.° Di-iodomalonic
Acid, CI2(COOH)2, is prepared from malonic acid, iodine, and iodic acid in formic
acid. It is extremely unstable ; methyl ester, m.p. 80°, can be obtained from
dibromomalonic ester and KI.
The mono- and di-halogen malonic acids serve as a connecting link between
malonic acid and tartronic and mesoxalic acids. Monobromo- and mono-iodocyan-
acetic Esters, CN.CHXCO2R, are obtained from sodium cyanacetic ester with
bromine or iodine in the cold. At higher temperatures dicyanosuccinic ester and
tricyano-trimethylene tricarboxylic esters are formed (C. 1900, II. 38, 1202).
Monothio - bis - malonic ester, S[CH(CO2R)2]2, Dithio- bis -malonic Ester,
S2[CH(CO2R)2]2, and tri-thio-bis-malonic ester, S3[CH(CO,R)2]2, are formed from
malonic ester and S2C12 (B. 36, 3721).
Alkyl Malonic Acids. — The general methods suitable for the
preparation of alkyl malonic acids are (i) reaction 5« (p. 477), con-
version of a-halogen fatty acids into a-cyano-fatty acids — the half
490 ORGANIC CHEMISTRY
nitriles of the malonic acid homologues ; and (2) reaction 6 (p. 478),
the replacement of the hydrogen atoms of the CH2 group in the malonic
esters by alkyls. First, with the aid of sodium ethoxide, or sodium in
ether (J. pr. Ch. 72, 537), monosodium malonic esters are made, which
alkyl iodides convert into mono-alkyl malonic esters. These are
further able to yield monosodium alkyl malonic esters, which alky-
logens change to dialkyl malonic esters — e.g. :
COaC2H. COaCaH, COaCaH, COaC2H. CO2C2H5
CHf > CHNa > CH.CH, > CNaCH8 > C(CH3)3
CO2C2H5 COtC2H5 CO2C2H, CO2C2H6 CO2C2HS
Malonic Ethyl Sodium Malonic Methyl Malonic Sodium Methyl Dimethyl
Ester. Ester. Ester. Malonic Ester. Malonic
Ester.
It has previously been mentioned under acetoacetic ester (p. 412) that the
reaction consists in the addition of sodium ethoxide to the carboxethyl group,
with the splitting-off of alcohol and the production of a double union, to which
the alkylogen attached itself, followed by the elimination of a sodium halide
(A. 280, 264) :
Alkyl malonic esters are also formed when alkyl oxalacetic esters lose CO,
(B. 31, 551).
Some of these dialkyl malonic acids are formed when complex carbon deriva-
tives are oxidized — e.g. dimethyl malonic acid results from the oxidation of
unsym. -dimethyl ethylene succinic acid, mesitonic acid, camphor, etc. The pro-
duction of dimethyl malonic acid in this manner proves the presence, in these
bodies, of the atomic grouping —
All mono- and dialkyl malonic acids, when exposed to heat, lose C02
and pass into mono- (B. 27, 1177) and dialkyl acetic acids (p. 476).
See Z. phys. Ch. 8, 452, for the affinities of the alkyl malonic acids. Consult
B. 29, 1864 ; J. pr. Ch. [2] 72, 537, upon the velocity of hydrolysis of the
alkyl malonic esters.
Isosuccinic Acid, Ethylidene Succinic Acid, Methyl Malonic Acid
[Methyl-propane Di-acid], CH3CH(CO2H)2, m.p. 130° with decom-
position, is isomeric with ordinary succinic acid or ethylene succinic
acid (p. 491), and is obtained (i) from ct-chloro- and a-bromo-propionic
acids through the cyanide (B. 13, 209), and (2) from sodium malonic
ester and methyl iodide (A. 347, 93).
When ethylidene bromide, CH3.CHBr2, is heated with potassium
cyanide and alkalis, the expected ethylidene succinic acid is not formed,
but by molecular rearrangement, ordinary ethylene succinic acid
results.
The acid is more soluble than ordinary succinic acid in water. If heated above
130°, it breaks up into carbon dioxide and propionic acid (p. 258) ; ethyl ester t
b.p. 196° ; methyl ester, b.p. 179° ; diamide, m.p. 216°.
ETHYLENE SUCCINIC ACID 491
For the rules of formation of the diamides oi homologous allkyl and di-alkyl-
malonic acids, see B. 39, 1596 ; C. 1905, II. 725 ; 1906, I. 1235, etc.
a-Cyanopropionic Ester, CH3CH(CN)CO2C2H8, b.p. 197-198°.
Bromisosuccinic Acid, CH3CBr(COaH)a, m.p. 118-119° (B. 23, R. 114).
Methyl Bromomalonic Ester, b.p.,, 115-118° (B. 26, 2356).
Ethyl Malonic Acid, C2H5.CH(CO,H)a, m.p. 111-5°. The ethyl ester, b.p. 200° ;
amide, m.p. 216°; Ethyl Bromomalonic Ester, b.p. 125° (B. 26, 2357).
Dimethyl Malonic Acid, (CH3)2C(CO2H)2, m-P- l85° with decomposition
(A. 247, 105) ; ethyl ester, b.p. 195° ; amide, m.p. 261° ; nitrile, m.p. 32°, b.p,22
64° ; dichloride, m.p. 165°. The latter, with aqueous pyridine, yields a poly-
meric anhydride, [(CHS)2C(CO)2O], (A. 359, 169), which can also be formed by
heating the monochloride, HOCOC(CH3)2COC1, m.p. 65° with decomposition ;
and also by prolonged heating of dimethyl ketene (p. 475) (B. 41, 2212).
In the case of the subjoined alkyl malonic acids, the boiling points of the
ethyl esters (inclosed in parentheses) are given, together with the melting points
of the acids.
Propyl Malonic Acid, CHSCH,CHCH(CO2H)2, m.p. 96° (219-222°).
Isopropyl Malonic Acid (CH,)2CH.CH(CO2H)2, m.p. 87° (213-214°).
Methyl Ethyl Malonic Acid, CH8(C2H6)C(CO2H)2, m.p. 118° (207-208°).
n.-Butyl Malonic Acid, CH8(CH2)3.CH(CO2H)2, m.p. 101-5°. Isobutyl
Malonic Acid, m.p. 107° (225°). sec.-Butyl Malonic Acid, CHa(C2H5)CH.CH-
(CO2H)2, m.p. 76° (233-234°). Propyl Methyl Malonic Acid, CH3(CH3.CH2-
CH2)C(CO2H)2, m.p. 107° (220-223°). Isopropyl Methyl Malonic Acid, m.p. 124°
(221°). Diethy I Malonic Acid, m.p. 121° (A. 292, 134) ; dimethyl ester, b.p. 205° ;
chloride, b.p. 197°, yields a polymeric anhydride, [(C2H6)aC(CO)2O]12, when treated
with pyridine and soda solution. Boiling hi benzene partially de-polymerizes
it, whilst when heated alone it is decomposed into diethyl ketene (p. 475) and COa
(A. 359, 159 ; B. 41, 2216) ; amide, m.p. 224° (B. 35, 854 ; A. 359, 174 ; C. 1906,
I. 1237). Di-ethy I Malonic Acid Nitrile, m.p. 44°, b.p.24 92°. Veronal is a urelde
of this acid (see Barbituric acid).
Pentyl Malonic Acid, CH3[CHa]4CH(CO2H)2, m.p. 82°. Dipropyl Malonic
Acid, (CH3CH2CH2)2C(CO2H)a, m.p. 158°. Cetyl Malonic Acid, CH8[CH2]16
CH(C02H)2, m.p. 122° (A. 204, 130 ; 206, 357 ; B. 24, 2781).
For alkyl and di-alkyl cyanacetic esters and amides, see also A. 340, 310.
THE ETHYLENE SUCCINIC ACID GROUP
Ethylene succinic acid and its alkyl derivatives, as mentioned in
the introduction, are characterized by the fact that when heated they
break down into anhydrides and water. The anhydride formation
takes place more readily in the alkyl succinic acids, the more hydrogen
atoms of the ethylene residue of the succinic acid are replaced by
alkyl radicals.
The alkyl succinic acids form anhydrides more readily with acetyl
chloride, and are more volatile in aqueous vapour than their isomeric
alkyl n-glutaric acids (A. 285, 212). The sym.-dialkyl succinic acids
show remarkable isomeric phenomena, which will be more fully discussed
under the symmetrical dimethyl succinic acids (p. 493).
The following serve to characterize a succinic acid : (i) the anhy-
dride ; (2) the anilic acid, which appears in the chloroform, ethereal,
or benzene solution of the anhydride ; (3) the anil, produced by
heating the anilic acid, or by the action of phosphorus pentachloride or
acetyl chloride on it (A. 261, 145 ; 285, 226 ; 309, 316).
The anhydrides of the succinic acids unite with alcohols to form
acid esters, which are also formed by partial exterification of the acids,
and by partial hydrolysis of the neutral esters. The production of
jymmetrically substituted succinic acids is effected mainly by means
unsymn
492 ORGANIC CHEMISTRY
of the two first methods ; the last is employed when preparing certain
isomeric acid esters (comp. C. 1904, I. 1484 ; A. 354, 117).
Ordinary Succinic Acid, Ethylene Dicarboxylic Acid, C02H.CH2-
CH2.CO2H, m.p. 185°, b.p. 235°, with decomposition into water and
succinic anhydride, is isomeric with methyl malonic acid, or isosuccinic
acid (p. 490). It occurs in amber, in some varieties of lignite, in resins,
in turpentine oils, and in animal fluids. It is formed in the oxidation
of fats with nitric acid, in the fermentation of calcium malate or
ammonium tartrate (A. 14, 214), and in the alcoholic fermentation
of sugar (p. 115).
In the general methods of formation (p. 476) ethylene succinic
acid has been in part the example chosen. It is produced (i) by the
oxidation of y-butyrolactone and of succinic dialdehyde.
(2) By the reduction of fumaric and maleic acids with nascent
hydrogen.
(3) By reducing (a) malic acid (hydroxysuccinic acid) and tartaric
acid (dihydroxysuccinic acid) with hydriodic acid, or by the fermen-
tation of these bodies ; (b) by the action of sodium amalgam on
halogen succinic acids.
It is a nucleus-synthetic product obtained in small quantities
(4) by the action of finely divided silver on bromacetic acid.
(50) By converting j3-iodopropionic acid (p. 289) into the cyanide
and decomposing the latter with alkalis or acids. (56) M. Simpson,
in 1861, was the first to prepare it synthetically from ethylene, by
converting the latter into the cyanide. Succinic acid is formed by
boiling its dinitrile with potassium hydroxide or mineral acids :
CH,CN
•I
CH2CN
Ethylidene chloride and potassium cyanide also yield ethylene cyanide (p. 499).
CHaCO,H.
(6) By the electrolysis of potassium ethyl malonic ester (p. 487)
the ester is produced.
(7) By the decomposition of *acetosuccinic esters, (8) of ethane
tricarboxylic acid, (9) of sym.-ethane tetracarboxylic acid.
Succinic acid crystallizes in monoclinic prisms or plates, and
has a faintly acid, disagreeable taste. At the ordinary temperature
it dissolves in 20 parts of water.
Uranium salts decompose aqueous succinic acid in sunlight into
propionic acid and CO2. The electric current decomposes the potas-
sium salt into ethylene, carbon dioxide, and potassium (p. 81).
Paraconic Acids, y-lactone carboxylic acids, are formed when sodium succinate
is heated with aldehydes and acetic anhydride (Fittig, A. 255, i). When succinic
acid, zinc chloride, sodium acetate, and acetic anhydride are heated to 200°,
small quantities of aa'-dimethyl £-acetyl pyrrole (B. 27, R. 405) are produced.
When calcium succinate is distilled, £-diketo-hexamethylene (Vol. II.) is
produced in small quantities (B. 28, 738).
Succinates : calcium salt, C4H4O4Ca+3H2O, separates from a cold solu-
tion, but when it is deposited from a hot liquid it contains only iH2O. WThen
ammonium succinate is added to a solution containing a ferric salt, all the iron
is precipitated as reddish-brown basic ferric succinate (separation of iron from
aluminium).
PYROTARTARIC ACID
493
Esters. Potassium Ethyl Succinate when clectrolyzed yields adipic ester (p. 505)
Monomethyl Succinate, m.p. 58°, is prepared from the anhydride and alcohol
(C. 1904, I. 1484). Dimethyl Succinate, CO2CH8.CH2.CH2CO2CHS, m.p. 19°,
b.p.10 80°. Diethyl Succinate, b.p. 216°. Sodium converts it into succinyl
ROCO.CH— CO— CHa
succinic ester, (q.v .). Ethylene Succinate (A. 280, 177).
CHa— CO— CH.COOR
Mono-alkyl Succinic Acids. Pyrotartaric Acid, Methyl Succinic
CHS.CH.CO2H
I , m.p. 112°, was first obtained in (i) the dry
CH8.CO2H
Distillation of tartaric acid. It is produced (2) from pyroracemic
»cid or its condensation product, keto-valerolactone carboxylic acid,
when heated with hydrochloric acid (A. 317, 22) :
CH3C(COOH).0V -C02 CH3CH.COOH
2CH.COCOOH > >CO >•
CHa- CO/ hHa° CH2COOH.
The remaining methods of formation correspond with those for the
production of succinic acid ; (3) by the reduction of ita-, citra-,
and mesa-conic acids (p. 515) ; (4) from ^3-bromobutyric acid and
propylene bromide by means of potassium cyanide ; (5) from a- and
J8-methyl acetosuccinic esters ; and (6) from a- and /J-methyl ethane
tricar boxy lie acids. The acid dissolves readily in water, alcohol, and
ether. When quickly heated above 200° it decomposes into water and
the anhydride. If, however, it be exposed for some time to a tem-
perature of 200-210°, it splits into CO2 and butyric acid. It undergoes
the same decomposition when in aqueous solution, if acted on by
sunlight in presence of uranium salts (B. 24, R. 310). Resolution into
its optically active components is effected by strychnine (B. 29, 1254).
Dextro-rotatory pyrotartaric acid is also formed when menthone is
oxidized.
Potassium Salt, C6H6O4K2 ; calcium salt, C5H6P4Ca+2H2O, dissolves with
difficulty in water ; methyl ester, b.p.20 153° ; ethyl ester, b.p"23 160° ; dimethyl
ester, b.p. 197° ; diethyl ester, b.p. 218° (B. 26, 337 ; C. 1900, I. 169 ; 1904, I.
1484).
Ethyl Succinic Acid, m.p. 98°. n-Propyl Succinic Acid, (A. 292, 137). /so-
butyl Succinic Acid, m.p. 107° (A. 304, 270).
(CH3)2CH.CHCO,H
Pimelie Acid, Isopropyl Succinic Acid, , m.p. 115*. was
CH,C02H
first prepared by fusing camphoric acid and tanacetogen dicarboxylic acid (B. 25,
335°) with potassium hydroxide. It may be synthetically obtained from aceto-
acetic or malonic esters (A. 292, 137 ; 298, 150), as well as from the products
of the action of potassium cyanide on isocaprolactone at 280° (C. 1897, I. 408)
sym.-Dialkyl Succinic Acids, CO2H.CHR'-CHR'.CO2H.
Symmetrical dimethyl succinic acid exists, like the other symmetrical disub-
stituted succinic acids — e.g. dibromosuccinic acid (p. 500), diethyl-, methyl-
ethyl-, di-isopropyl-, and diphenyl-succinic acids — in two different forms, having
the same structural formulae.
Dihydroxysuccinic acid or tartaric acid occurs in two active and two inactive
forms (one can be resolved and the other cannot), which are satisfactorily explained
by van 't Hoff's theory of asymmetric carbon atoms (p. 30). The pairs of isomeric
dialkyl succinic acids, also containing asymmetric carbon atoms, manifest certain
analogies with paratartaric acid (racemic acid), and anti- or meso-tartaric acid.
Hence it is assumed that their isomerism is due to the same cause. The higher
melting, more difficultly soluble modification is called the para-form, whilst the
494 ORGANIC CHEMISTRY
meso- or anti-form is more readily soluble, and melts lower (Bischofj, B. 20, 2990 ;
21, 2106). However, this assumption is doubtful, inasmuch as not one of the
constantly inactive dialkyl succinic acids has ever been converted into an active
variety (B. 22, 1812). Bischoffhas set forth a theory of dynamical isomerism (B. 24,
1074, 1085) in which he presents views in regard to the equilibrium positions of
the atoms and radicals, joined to the two asymmetric carbon atoms, in the
symmetrical dialkylic succinic acids.
Isomeric pairs of the dialkyl succinic acids are formed (according to method 2,
p. 477) by the reduction of dialkyl maleic anhydrides, such as pyrocinchonic
anhydride (p. 518), by means of HI or sodium amalgam (B. 20, 2737 ; 23, 644) ;
from a-monohalogen fatty acids by finely divided silver (method of formation 4)
(B. 22, 60) ; from a-monohalogen fatty acids by the action of potassium cyanide
(B. 21, 3160) ; from aceto-dialkyl-succinic esters by elimination of the acetyl
group (method 8) ; from sym.-dialkyl ethane polycarboxylic acids by heating
them with hydrochloric (method 9) (comp. p. 492).
In all these reactions both dialkyl succinic acids are formed together, and
may be separated by crystallization from water.
sym.-Dimethyl Succinic Acids, CO2H.CH(CH3)— CH(CH3)CO2H.
The para-acid, m.p. 192-194°, is soluble in 96 parts of water at 14°. It
forms needles and prisms, which lose some water upon melting. If the acid be
heated for some time to 180-200°, it yields a mixture of the anhydrides of the
para- and anti-acid, C6HtO3, m.p. 38° and 87°. With water each reverts to its
corresponding acid. When acetyl chloride acts on the para-acid, its anhydride,
m.p. 38°, is the only product. This crystallizes from ether in rhombic plates, and
unites with water to form the pure para-acid (B. 20, 2741 ; 21, 3171 ; 22, 389 ;
23, 641 ; 29, R. 420).
If the para-acid be heated to 130° with bromine, it yields pyrocinchonic
anhydride, C6H6O3 (p. 518). Both acids, when digested with bromine and phos-
phorus, yield the same bromo-dimethyl-succinic acid, C8H9BrO4, m.p. 91°. Zinc
and hydrochloric acid change it to the anti-acid (B. 22, 66). The ethyl ester of
the para-acid (from the silver salt) b.p. 219° ; methyl ester, b.p. 199°.
The meso- or anti-acid, m.p. 120-123° (after repeated crystallizations from
water) (analogous to antitartaric acid and maleic acid) dissolves in 33 parts of
water at 14°. It crystallizes in shining prisms. It yields its anhydride, C6H8O3,
m.p. 87°, when heated to 200°. It regenerates the acid with water. If the
anti-acid be heated with hydrochloric acid to 190°, it becomes the para-acid.
The methyl ester, b.p. 200° ; ethyl ester, b.p. 222°. When the anti-acid is esterified
with HC1, it yields a mixture of the esters of the anti- and para-acid (B. 22, 389,
646 ; 23, 639). The ethyl ester is also obtained when a-iodopropionic ester
is shaken with mercury in sunlight (C. 1902, I. 408).
The monomethyl ester of the para-acid, m.p. 38°, and of the anti-acid, m.p. 49°,
are obtained by the action of methyl alcohol on the anhydrides (C. 1904, 1. 1484).
sym.-Methyl Ethyl Succinic Acids, CO8H.CH(CH3).CH(C2H5)CO2H. The para-
acid, m.p. 179° ; anti- or meso-acid, m.p. 101° (A. 298, 147).
sym.-Methyl Isopropyl Succinic Acids : The para-acid, m.p. 174° ; meso-
acid, m.p. 125° (B. 29, R. 422).
sym.-Diethyl Succinic Acids. — The para-acid, m.p. 189-192°; anti-acid,
m.p. 129° (B. 20, R. 416 ; 21, 2085, 2105 ; 22, 67 ; 23, 650).
The para- and meso-forms of the sym.-di-n. -propyl succinic acid, di-isopropyl
succinic acid, and propyl isopropyl succinic acid are prepared by the introduction
of propyl or isopropyl groups into propyl or isopropyl cyanosuccinic ester
followed by hydrolysis and decomposition of the condensation "products. Di-iso-
propyl succinic acid also results from bromisovaleric ester and silver (A. 292,
162 ; C. 1900, I. 846, 1205). Other sym.-dialkyl succinic acids, see C. 1901, 1. 167.
Unsymmetrical Succinic Acids.
uus.-Dimethyl Succinic Acid, CO2H.CH2.C(CH3)2.CO2H, m.p. 140°, is synthe-
sized from a-dimethyl ethane tricarboxylic ester by the action of boiling sulphuric
acid. The ester is the reaction product of bromisobutyric ester and sodium
malonic ester (C. 1898, I. 885). It can also be obtained from dimethyl cyan-
ethane dicarboxylic ester, the product of reaction of sodium cyanacetic acid
and a-bromisobutyric ester ; from the acid nitrile, the product of the inter-
action of potassium cyanide and j8-chlorisovaleric acid (C. 1899, I. 182) ; also,
from its nitrile (p. 499). The imide (p. 497) is obtained by oxidation of mesitylic
SUCCINIC ANHYDRIDES 495
acid. Esterification of uns. -dimethyl succinic acid proceeds by first attacking the
carboxyl group attached to the CH2-group, producing uns,-Dimethyl Succinic a-
Mono-ethyl Ester, COZH..C(CHS)2.CH2CO2C1,H6, m.p. 70°, b.p.14 150°. This sub-
stance can also be obtained by the action of alcohol on dimethyl succinic anhy-
dride. Partial hydrolysis of nns.-Dimethyl Succinic Diethyl Ester, b.p. 215°, pro-
duces the liquid isomer dimethyl succinic ^-mono-ethyl ester (Private communica-
tion of Anschutz and Guttes). uus.-Dimcthyl Succinic Monomethyl Ester, m.p. 42°
and 51° (C. 1904, I. 1485).
Trimethyl Succinic Acid, CO2H.CH(CH3)— C(CH3)2.CO2H, m.p. 151° (A. 292,
142), results on hydrolyzing the tricarboxylic ester (B. 24, 1923) produced in
the action of bromisobutyric ester on sodium methyl malonic ester, or sodium
a-cyanopropionic ester, as well as in the oxidation of camphoric acid (B. 26,
2337) '• an<3 by fusing camphoronic acid with potassium hydroxide (Vol. II. ;
A. 302, 51). The formation of trimethyl succinic anhydride from camphoronic
acid by distillation is rather important in the recognition of the constitution of
camphor (B. 26, 3047). Trimethyl succinic acid is resolved into its optically
active components by means of the quinine salts (C. 1901, I. 513).
Tetramethyl Suceinic Acid, CO2H.C(CH3)2.e(CH3)2CO2H, m.p. 190-192,
with loss of water, is formed, together with trimethyl glutaric acid (p. 504), when
o-bromisobutyric acid (or its ethyl ester) is heated with silver (B. 23, 297 ; 26,
1458) ; also by electro-synthesis from potassium dimethyl malonic ester, and
from azobutyronitrile (p. 397) (A. 292, 220) ; monomethyl ester, m.p. 63°.
Tetra-ethyl Succinic Acid, m.p. 149° with conversion into anhydride, and
Tetrapropyl Succinic Acid, m.p. 137°, are obtained by hydrolysis of the respective
dialkyl malonic mono-esters (C. 1905, II. 670 ; 1906, II. 500).
These tetra-alkylated succinic acids pass very readily into their an-
hydrides.
Chlorides of the Ethylene Succinic Acid Group.
Of the possible chlorides, the monochloride, C1.CO.CH2.CH2.CO2H, is only
known in the form of its ethyl ester, b.p.90 144°, which results from the action of
POC13 (B. 25, 2748) on sodium succinic ethyl ester.
Succinyl Chloride, m.p. 16°, b.p.25 103°, results from the action of PC15 on
succinic acid.
Two formulae have been suggested for this substance, a symmetrical (i), and
an unsymmetrical one (2) :
CH2COC1 CH2.CC18X
(i) I (2) | >0
CH2COC1 CH2.CO /
lis latter view would make succinyl chloride a dichloro-substitution product
of butyrolactone, into which it passes on reduction. The behaviour of succinyl
: chloride towards zinc ethide is in harmony with its lactone formula, for it then
yields y-diethyl butyrolactone (p. 374), and in the presence of benzene and alumi-
nium chloride it chiefly affords y-diphenyl butyrolactone (B. 24, R. 320). A small
quantity of dibenzoyl ethane, C6H5CO.CH2CH2.COC,H6, is produced at the
same time. These reactions, whilst supporting the unsymmetrical formula, do
not completely exclude the symmetrical representation (comp. B. 30, 2268).
Pyrotartryl Chloride, C,H,O2C12, b.p. 190-195° (B. 16, 2624). uns.-Dimethyl
Succinyl Chloride^ C,H§Oa.Cla, b.p. 200-202° (A. 242, 138, 207).
Anhydrides of the Ethylene-Succinic Acid Group.
The ready formation of anhydride is characteristic of ethylene
succinic acid and its alkyl derivatives. It proceeds the more easily
the more the hydrogen atoms of the ethylene group are replaced
by alcohol radicals (p. 492).
Formation. — (i) By h'eating the acids alone. (2) By the action
of P2O5 (B. 28, 1289), PC15 or POC13 (A. 242, 150) on the acids.
(3) By treating the acids with the chloride or anhydride of a
496 ORGANIC CHEMISTRY
monobasic fatty acid, e.g. acetyl chloride or acetic anhydride (Anschiitz,
A. 226, i) :
CHjCCX CH3.COv
I >0+ >0
CH2CCK CH3OX
CH2.COOH CH,COV CH3.C(
+2CH8COC1 =| >0+ >0+2HC1.
CH..COOH
(4) When the chloride of a dicarboxylic acid acts (a) on the
acid, or (b) on anhydrous oxalic acid (A. 226, 6) :
CH2.CC12, COOH CH2COX
>0+ = | >0+2HCl+CO+COr
CH,CO / COOH CH2COX
CH8C(X
CH2OX
Succlnic Anhydride, J ;>O, m.p. 120°, b.p. 261°. Methyl Succinic
Anhydride, Pyrotartaric Anhydride, m.p. 32°, b.p. 247° (A. 336, 299 ; C. 1904,
I. 1485). Ethyl Succinic Anhydride, b.p. 243°. Isopropyl Succinic Anhydride,
b.p. 250°. Para- and Meso-sym.-dimethyl Succinic Anhydride, m.p. 38° and 87°,
respectively (B. 26, 1460 ; C. 1899, II. 610). Meso-sym.-methyl Ethyl and
Meso-sym.-diethyl Succinic Anhydrides, m.p. 244°, b.p. 245°. unsym.-Dimethyl
Succinic Anhydride, m.p. 29°, b.p. 219°. Trimethyl Succinic Anhydride, m.p. 31°,
b.p.7tt 231°; b.p.12 101°. Tetramethyl Succinic Anhydride, m.p. 147°, b.p.
230'5°. Tetra-ethyl Succinic Anhydride, m.p. 86°, b.p. 270°. Tetrapropyl
Succinic Anhydride, m.p. 370°.
Properties and Reactions. — Succinic anhydride has a peculiar, faint, pene-
trating odour. It can be recrystallized from chloroform. It reverts to succinic
acid in moist air, but more rapidly when boiled with water. It yields succinic
alkyl ester acids with alcohols. Ammonia and amines change it to succinamic
and alkyl succinamic acids. PC15 changes it to succinyl chloride. Sodium
amalgam reduces it to butyrolactone (B. 29, 1193); reduction of homologous
succinic anhydrides by sodium and alcohol produces y-lactones and even 1,4-
glycols (comp. pp. 310, 373). If the anhydride is boiled for some time it loses
CO 2 and changes to the dilactone of acetone di acetic acid, CO(CH2.CH2-
CQ2H)2 (q.v.)', P2S 3 converts succinic acid and sodium succinate into thiophene,
CH=CH — S — CH=CH (q.v.). The homologues of succinic anhydride resemble
the latter in behaviour.
unsym.-Dimethyl succinic anhydride is partially decomposed by Al2Cle in
chloroform into CO, H2O,and dimethyl acrylic acid, (CHS)2C:CHCOOH (C. 1902,
I- 567).
Peroxides.
Succinyl Peroxide, (C4H4O4) , is obtained from succinyl chloride and sodium
peroxide. It is a very explosive crystalline powder (B. 29, 1724). Succinic
Peroxide, O2(COCH2CH2COOH)2, m.p. 124° with decomposition, is prepared from
succinic anhydride and 7-5 per cent. H2O2 solution. It explodes when heated,
and decomposes in xylene solution into CO2, a small quantity of adipicacid (p. 505),
succinic anhydride, and other bodies. Water hydrolyses it into succinic acid
and succinic hydrogen peroxide, HOCOCH2CH2CO.OOH, m.p. 107° with decom-
position, which decomposes on careful heating into CO2, H2O, and acrylic acid
(C. 1904, II. 765).
NITROGEN-CONTAINING DERIVATIVES OF THE ETHYLENE SUCCINIC
ACID GROUP
Ethylene succinic acid, like oxalic acid, yields an imide, a diamide,
a nitrile acid and dinitrile :
CH2C02H CH2COv CH2CONH, CH2CO2H CH2CN
I I >NH | | |
CH.CONH, CH2COX CH2CONH3 CH2CN CH2CN
Succinamic Succinimide. Succinamide. S-Cyanopropionic Hthylene
Acid. Acid. Cyanide.
SUCCINIMIDE 497
(a) Amldo- Acids (A. 309, 316). — Most of these have been prepared by decom-
posing the imides with alkalis or barium hydroxide. They are also formed on
adding ammonia, primary aliphatic amines, and aromatic amines (e.g. aniline and
phenyl-hydrazine) to acid anhydrides. They behave like oxamic acid (p. 483).
When heated, or when treated with dehydrating agents, e.g. PC15 or CH3COC1,
they become converted into imides, which bear the same relation to them that the
anhydrides sustain to the dicarboxylic acids. Succinamic Acid, COaH.CH2CH2.-
CONHr is obtained from succinimide by the action of barium hydroxide solution.
Succinamic Methyl Ester, m.p. 90°, is obtained from succinimide and methyl
alcohol at 178° (C. 1899, II. 864). Succinethylamic ^«d,CO2H.CHaCH2.CONHC2H,
(A. 251, 319). Succinanilic Acid, COaHCH2CHaCONHC6H5 (B. 20, 3214) ;
methyl ester, m.p. 98°, is obtained from succinanil (p. 498) and sulphonic acid
in methyl alcoholic solution, and P2S. in toluene produces thiosuccinanil,
CHa.CCX
A\N.C6H8, m.p. 167°, which is split by alkalis into thiosuccinanilic acid,
H2.CSX
HOCO.CH2CH2CSNHC6H5, m.p. 107° (B. 39, 3303). \\nsym.-Dimethyl Succinct-
nilic Acid, COaHC(CH8)2CH2CONHC6H5, m.p. 189°.
(b) Imides. — These are produced (i) on heating the acid anhy-
drides in a current of ammonia ; (2) when the ammonium salts,
diamides, and amido-acids are heated ; (3) from the dinitriles, by partial
hydration (C. 1902, I. 711). They show a symmetrical structure,
as will be explained in connection with succinanil.
CH2.COV
Succinimide, I /NH, m.p. 126°, b.p. 288°, crystallizes with
CH2.CO/
water, and has the character of an acid, as the hydrogen of the NH-
group can be replaced by metals.
Potassium Succinimide, C2H4(CO)2NK ; Sodium Succinimide (B.
28, 2353) ; Silver Succinimide (A. 215, 200) ; Potassium Tetrasuccini-
mide Tri-iodo-iodidey (C^OalSOJs.KI (B. 27, R. 478 ; 29, R. 298).
The cyclic imides are readily broken down by alkalis and alkaline
earths :
CH.CCX H20 CH2CO.OH
I >NH > I
CHjCCK CH2CO.NHt
On distilling succinimide with zinc dust, pyrrole (p. 318) is formed ;
when heated with sodium in alcoholic solution it is converted into
etramethylene imide or pyrrolidine (p. 335). Electrolytic reduction
produces y-butyrolactone or pyrrolidone (p. 395).
CHa.COv CH2.CO v CHa.CHa,
NH -< - | >NH - > | >NH | >NH
CHa.CO/ CHa.CH/ CH2.CH/
Pyrrole. Succinimide. Pyrrolidone. Pyrrolidine.
Hypochlorous acid, and hypobromous acid acting on succinimide, and iodine
»n silver succinimide produce : Succinochlorimide, C2H4(CO)2NC1, m.p. 148° ;
)uccinobromimide, C2H4(CO)2NBr, m.p. 174° with decomposition, and Succiniodo-
mide (B. 26, 985). Phosphorus pentachloride converts succinimide into dichloro-
CC1.CO v
e naleinimide chloride, || yNH, pentachloropyrrole, C4C15N, and the hepta-
N hloride, C4C17N (A. 295, 86). Bromine and potassium hydroxide convert
uccinimide into j5-amidopropionic acid (p. 393) :
I eH22:c£>NBr+4KOH = gg^0»K + KBr+K2C08-f HaO.
VOL. I. 2 K
498 ORGANIC CHEMISTRY
Sodium methoxide changes succinobromimide by a molecular rearrange-
ment into Carbomcthoxy-p-amidopropionic Ester, CH,O.CO.NHCHaCHaCOaCHs,
m.p. 33'5° (B. 26, R. 935).
Methyl Succinimide, CaH4(CO)aN.CHa, m.p. 66-5°, b.p. 234°, is obtained
from the oxime of laevulinic acid (p. 421) by the action of concentrated sulphuric
acid (A. 251, 318).
Ethyl Succinimide, m.p. 26°, b.p. 234°, is formed when ethyl iodide
acts on potassium succinimide. It yields ethyl pyrrole when it is distilled with
zinc dust. Isopropyl Succinimide, m.p. 61°, b.p. 230°. Isobutyl Succinimide,
m.p. 28°, b.p. 247° (B. 28, R. 600).
Phenyl Succinimide, Succinanil, CaH4(CO)a.N.C6Hf, m.p. 150°, is converted
CC1— CO v
by PCI, into dichloromaleic anil dichloride, || >NC,H,, the lactam of
CC1— CC1/
CC1=CCK
y-anilidoperchlorocrotonic acid and tetrachlorophenyl pyrrole, | ^>NC,H5.
ca—ccK
This last fact, and the reduction of dichloromaleic dichloride to y-anilidobutyro-
CHa.CO v
lactam or n-phenyl butyrolactam, | yNC6H6, indicate that the symmetrical
CHa.CHa
formula properly represents both succinanil and succinimide (A. 295, 39, 88).
CHj.CH.CO v
Pyrotartrimide, \ /NH, m.p. 66°. n-Alkyl Pyrotartrimide (B. 30,
CH,.OCX
3039). sym. -Dimethyl Succinimide (B. 22, 646). unsym.-Dimethyl Succinimide,
m.p. 1 06°, is obtained by heating ao-dimethyl succinonitrile acid (C. 1899, I.
873) ; also by oxidation of mesitylic acid (A. 242, 208 ; B. 14, 1075). unsym.-
Dimethyl Succinanil, m.p. 85°. Trimethyl Succinanil, m.p. 129°. Tetramethyl
Succinanil, m.p. 88° (A. 285, 234; 292, 176, 184). Pimelimide, m.p. 60° (A. 220,
276).
(c) Diamides and Hydrazides.
Succinamide, NH2CO.CH2CHaCONHa, is produced like oxamide. It crystal-
lizes from hot water in needles. At 200° it decomposes into ammonia and
succinimide.
Succinodibromodiamide, NH2CO[CH8]aCONBra, is obtained from succinamide
and KBrO (see also fl-Lactyl Urea, p. 444). Pyrotartr amide, m.p. 225° (B. 29.
CH8CO.NHNH,
R. 509). Succinohydrazide, \ , m.p. 167° (J. pr. Ch. [2] 51, 190 ;
CHaCO.NHNHj
B. 39, 3376).
(d) Cyclic Diamides. — Ethylene Succinyl Diamide, \
CH2CONH.CH,
(B. 27, R. 589). Succinophenylhydrazide, i-Phenyl-3,6-Orlhopiperazone,
/~*TT f*/"\ "M" ("* JT
| I 5, m.p. 199°, is obtained from the hydrochloride of
CH2CO.NH
phenylhydrazine and succinyl chloride (B. 26, 674, 2181) ; whilst
succinic anhydride and phenylhydrazine yield the isomeric n-anilino-
succinimide C2H4(CO)2 N.NHC6H5, m.p. 155°.
(e) Nitrilic Acids and Dinitriles. — Dimethyl Cyanopropionic Ester t
CN.CH2.C(CH3)2CO2C2H5, b.p. 218°, results when dimethyl cyano-
succinic mono-ethyl ester is heated (C. 1899, I- ^74)-
Dinitriles are produced from alkylene bromides (the addition pro-
ducts of bromine and the defines) by treatment with potassium cyanide.
Absorption of water converts these dinitriles into the ammonium salts
of the corresponding acids, the synthesis of which they thus facilitate,
HALOGEN COMPOUNDS OF THE SUCCINIC ACID GROUP 499
When reduced, they take up eight atoms of hydrogen and become the
diamines of the glycols — e.g. :
CHS.CO,H
CH2.CO2H
CH2.CH2.NHa
CH2.CH2.NH2
CH2OH CHS CH2Br CH2.CN
CH, "^CH," ^CHjBr" * CH2.CN~
Succinonitrile, Ethylene Cyanide, CN.CH2CH2.CN, m.p. 54*5°, b.p.2o
159°, is an amorphous, transparent mass (C. 1901, II. 807), readily
soluble in water, chloroform and alcohol, but sparingly soluble in ether.
It is also obtained by the electrolysis of potassium cyanacetate (p. 65).
It yields ethylene succinic acid when saponified, and tetramethylene diamine
upon reduction. It combines with 4HI (B. 25, 2543). Paraformaldehyde, glacial
acetic acid and sulphuric acid convert it into methylcne succinimide, (C2H4.C2O2N)2-
CH2, m.p. above 270° (J. pr. Ch. [2] 50, 3). When heated with water and sul-
phuric acid it forms succinimide (C. 1902, I. 711).
Pyrotartaric Nitrile, m.p. 12°, is obtained from allyl iodide and two molecules
of KNC (A. 182, 327 ; B. 28, 2952).
unsym-Dimethyl Succinic Nitrile, CN.CH2C(CH3)2CN, b.p. 219° (B. 22, 1740).
(/) Oximes.— Succinyl Hydroxamic Acid, CO2H.CH2CH2.C( : N.OH)OH
(B. 28, R. 999). Succinyl Hydroxamic Tetracetate, m.p. 130° (B. 28. 754). Hy-
CH2.C(:NOHK
clroxylamine converts succinonitrile into Succinimidoxime, \ /NH,
CH2.CO /
CH,.C(:NOHK
m.p. 197° (B. 24, 3427), and Succinimide Dioxime, \ >NH, m.p. 207°
CHj.CONOH)/
(B. 22, 2964).
HALOGEN SUBSTITUTION PRODUCTS OF THE SUCCINIC ACID GROUP
The monosubstitution products are obtained (i) by the direct action of halogens
on the acids, their esters, chlorides or anhydrides. In case of the acids, it is
advisable to act on them with amorphous phosphorus and bromine (B. 21,
R. 5) ; (2) by the addition of a halogen hydride to the corresponding unsaturated
dicarboxylic acid of thefumaric and maletc groups (A. 254, 161) ; (3) by the action
of a halogen hydride, and (4) of PC16 or PBr6 on the corresponding a-mono-
hydroxyethylene dicarboxylic acids (A. 130, 21); (5) from aminosuccinic acids
by means of potassium bromide, sulphuric acid, bromine and nitric oxide (B. 28,
2769).
Inactive Chlorosuccinic A cid, CO 2H.CHClCHa.CO2H, m.p. 152°, is formed from
fumaric acid and hydrochloric acid : dimethyl ester, b.p.14 106-5° ; diethyl ester.
b.p.16 122° ; anhydride, m.p. 41°, b.p.lt 126° (A. 254, 156 ; B. 23, 3757).
d-Chlorosuccinic Acid, m.p. 176° with decomposition, is obtained from 1-malic
acid by means of PC15 and water. Its silver salt is converted into d-malic acid
when it is boiled with water ; dimethyl ester, b.p.1B 107° ; chloride, b.p.n 92° ;
anhydride, b.p.20 138° (B. 28, 1289).
l-Chlorosuccinic Acid is prepared from 1-aspartic acid, which can be changed
to 1-malic acid. Starting, therefore, with 1-aspartic acid, it is not only possible
to prepare 1-chlorosuccinic acid and 1-malic acid, but with the aid of the latter we
can obtain d-chlorosuccinic acid, which can be transposed into d-malic acid
(p. 55) :
rl-Chlorosuccinic Acid •<- d-Malic Acid
I-Aspartic Acid ^
> d
Acid >• d-Chlorosuccinic Acid.
On the other hand, 1-chloro- and 1-bromo-succinic acid, which yield 1-malic
acid with silver oxide, give, with ammonia, d-aminosuccim'c acid, from which
5oo ORGANIC CHEMISTRY
d-malic acid can be obtained on boiling the substance with barium hydroxide
solution (Walden's Inversion, pp. 55, 364. 388) (B- 30, 2795) :
1-Chlorosuccinic Acid > 1-Malic Acid
d-Aminosuccinic Acid ^ d-Malic Acid.
Inactive Bromosuccinic A cid, CO 2H.CHBrCH2.CO2H, m.p. 160°, is prepared
from hydrobromic acid and fumaric acid. It is decomposed by alkalis into its
components (A. 348, 261); dimethyl ester, b.p.10 110°; anhydride, m.p. 31°,
b.p.n 137°.
d-Bromosuccinic Dimethyl Ester is formed from 1-malic acid and PBr5, b.p.M
124° (B. 28, 1291).
\-Bromosuccinic Acid, is prepared from 1-aspartic acid (B. 28, 2770 ; 29, 1699).
m.p. 173° with decomposition.
Monoiodosuccinic Acid has only been obtained as a basic lead salt (B. 30, 200).
The free, inactive acids and their esters, when heated at the ordinary pressure,
break down into a halogen acid and fumaric acid and its ester, whilst the
anhydrides yield the halogen hydride and maleic anhydride (A. 254, 157). Moist
silver oxide converts bromosuccinic acid into inactive malic acid (q.v.), which can
thus be synthesized in this way.
The addition of a halogen acid to ita-, citra-, and mesaconic acids produces
chloropyrotartaric acids, C5H7C1O4 :
(1) Itachloropyrotartaric Acid, m.p. 140-141° (comp. Paraconic Acid and
Itamalic Acid).
(2) Mesa- or Citrachloropyrotartaric Acid, m.p. 129° (A. 188, 51; C. 1899, I.
1070).
Bromopyrotartaric Acids, C6H2BrO4 :
(1) Itabromopyrotartaric Acid, m.p. 137*.
(2) Citrabromopyrotartaric Acid, m.p. 148°.
Dihalogen Substitution Products are produced (i) by the direct action of
bromine and water on the acids ; (2) by the addition of halogen acids to the
monohalogen unsaturated acids of the/w marie and maleic series ; (3 ) by the addition
of halogens — particularly bromine — to the unsaturated acids of the fumaric
and maleic series.
When hydrobromic acid is added to fumaric and maleic acids they yield the same
monobromosuccinic acid, but with bromine, fumaric acid forms the sparingly soluble
dibromosuccinic acid, whilst maleic acid and bromine yield the easily soluble iso-
dibromosuccinic acid and fumaric acid. These two dibromosuccinic acids have the
same structural formula, they are symmetrical in arrangement, and their isomerism
is probably due to the same cause prevailing with the dialkyl sym.-succinic acids
(p. 494 ). Yet they are intimately related to racemic and mesotartaric acids, which
were first synthetically prepared by means of the dibromosuccinic acids. Inasmuch
as fumaric acid yields racemic acid when oxidized, therefore the sparingly soluble
dibromosuccinic acid, the dibromo-addition product of fumaric acid, should cor-
respond with racemic acid, and isodibromosuccinic acid with mesotartaric acid.
However, the transposition reactions of the dibromosuccinic acids show many
contradictions.
Dichlorosuccinic Acid, m.p. 215° with decomposition, is prepared from fumaric
acids and liquid chlorine ; methyl ester, m.p. 32° (A. 280, 210).
Isodichlorosuccinic Acid, m.p. 170° with decomposition, is obtained from the
anhydride, m.p. 95°, the addition product of maleic anhydride and liquid chlorine.
When heated, the anhydride changes to chloromaleic anhydride (A. 280, 216).
Dibromosuccinic Acid, C2H2Bra(CO2H)2, consists of prisms which are not
very soluble in cold water. When heated to 200-235° it breaks up into HBr and
bromomaleic acid ; and with acetic anhydride it yields bromomaleic anhydride
and acetyl bromide ; methyl ester, m.p. 62° ; the ethyl ester, m.p. 68°.
Isodibromosuccinic Acid, C2H2Br2(CO2H)2, m.p. 160°, is very soluble in
water. It decomposes at 180° into HBr and bromofumaric acid (p. 514). Its
anhydride, C,H2Br?(CO)2O, m.p. 42°, is formed from maleic anhydride and
bromine. At 100° it breaks down into HBr and bromomaleic anhydride (A. 280,
207). The anilic acid, m.p. 144°. The anil, m.p. 177° (A. 292, 233 ; 239, 143).
When reduced, both acids yield ethylene succinic acid ; when boiled with potas-
sium iodide they change to fumaric acid, whilst boiling sodium hydroxide or
GLUTARIC ACID 501
barium hydroxide solutions convert them into acetylene dicarboxylic acid (A. 272,
127). The sparingly soluble dibroma acid, when boiled with water, passes into
bromomaleic acid, whilst the readily soluble acid, under like treatment, becomes
converted into bromofumaric acid. Two hundred parts of boiling water convert
the difficultly soluble dibromo-acid, in the presence of the brominated unsaturated
acid, into mesotartaric acid, together with a little racemic acid, whilst the readily
soluble acid yields much racemic acid and but little of the mesotartaric acid
(A. 292,295; 300,i).
The silver salt of the difficultly soluble dibromo-acid changes on boiling with
water to mesotartaric acid (q.v.), whilst racemic acid is obtained under similar
conditions from the easily soluble isodibromosuccinic acid (B. 21, 268). Much
mesotartaric acid with but little racemic acid is formed on boiling the barium or
calcium salt of the difficultly soluble dibromosuccinic acid. The contradictions
in these reactions are made clearer in the scheme which follows :
KMn04
Fumaric Acid ^- Racemic Acid.
Dibromosuccinic Acid >• Mesotartaric Acid (in quantity).
KMnO4
Maleic Acid >• Mesotartaric Acid.
Isodibromosuccinic Acid >• Racemic Acid (in quantity).
Trichlorosuccinic Acid is a crystalline, exceedingly soluble mass, obtained on
exposing chloromaleic acid, water and liquid chlorine to sunlight (A. 280, 230).
Tetrachlorosuccinanil, m.p. 157°, is formed together with dichloromaleic anil
chloride (p. 514), when PC15 acts on dichloromaleic anil (A. 295, 33).
Tribromosuccinic Acid, C2HBr3(CO2H)2, m.p. 136°, is produced when
bromine and water act on bromomaleic acid and isobromomaleic acid. The
aqueous solution decomposes at 60° into CO2, HBr, and dibromacrylic acid,
CsH2Br2O2 (p. 295). Alkalis convert it into dibromomalelc acid ; whilst excess
of ammonia produces monobromofumaric acid (A. 348, 264).
Dibromopyrotartaric Acids. — The addition of bromine to ita-, citra -and mesa-
conic acids gives rise to three dibromopyrotartaric acids, which upon reduction
revert to the same pyrotartaric acid (p. 493).
The ita-, citra"-, and mesa-dibromopyrotartaric Acids, C5H8BraO4, are
distinguished by their different solubility in water. The ita- compound changes
to aconic acid, C5H4O4, when the solution of its sodium salt is boiled ; the citra-
and mesa- compounds, on the other hand, yield bromomeihacrylic acid (p. 297).
An excess of potassium hydroxide will convert citradibromopyrotartaric acid
into bromomesaconic acid (p. 516).
GLUTARIC ACID GROUP
Glutaric acid and its alkyl derivatives, like ethylene succinic acid,
are characterized by the fact that when heated they break down into
the anhydride and water. The anhydrides readily yield anilic acids,
from which anils can be obtained by the withdrawal of water. The
glutaric acids resemble the ethylene succinic acids in behaviour, but
they are changed to anhydrides with greater difficulty by acetyl
chloride, and are not so volatile with steam.
Glutaric Acid, Normal Pyrotartaric Acid [Pentane Diacid]
CH2<CH2CO*H' m-P- 97°» is isomeric with monomethyl succinic acid or
ordinary pyrotartaric acid, as well as with ethyl and dimethyl
malonic acids (p. 491). It was first obtained by the reduction of a-
hydroxyglutaric acid with hydriodic acid. It may be synthetically
prepared from trimethylene bromide (p. 322), through the cyanide ;
502 ORGANIC CHEMISTRY
from acetoacetic ester by means of the acetoglutaric ester (q.v] ; from
glutaconic acid (p. 520), and from propane tetracarboxylic acid or
methylene dimalonic acid, C3H4(CO2H)4, by the removal of 2CO2 ;
from hydroresorcinol and potassium hypobromite (B. 32, 1871) ; by
electrolysis of a mixture of potassium malonic ester and succinic ester
(C. 1903, II 1053). Glutaric acid crystallizes in large monoclinic
plates, and distils near 303°, with scarcely any decomposition. It is
soluble in 1*2 parts water at 14°.
The calcium salt, C6H,O4Ca+4H2O, and barium salt, C6H,O4Ba-f5H2O, are
easily soluble in water ; the first is more readily in cold than in warm water
(like calcium butyrate, p. 259); monomethyl ester, b.p.ao 153° (B. 26, R. 276;
C. 1900, 1. 169) ; ethyl ester, b.p. 237°.
The anhydride, C6H,O,, m.p. 56-57°, forms on slowly heating the acid to 230-
280°, and in the action of acetyl chloride on the silver salt of the acid.
Glutarimidg, C3H,(CO)2NH, m.p. 152°, is formed when ammonium glutarate
is heated ; when trimethylene cyanide (q.v.) is heated with sulphuric acid and
water to 180-200* (C. 1902, I. 711), and by oxidation of pentamethylene imine
(p. 336) or piperidine with H2Oa (B. 24, 2777). When heated to redness with
zinc dust, a little pyridine is formed (B. 16, 1883).
Glutaric Peroxide, O2(COCH2CH2CH2COOH)2> m.p. 108° with decomposition,
is prepared from glutaric anhydride and H,,O2. On being heated it yields a
little suberic acid (p. 506) (C. 1904, II. 766).
Glutaric Dihydrazide, (CH2)8(CONHNH2)a, m.p. 176°. Glutaric Diazide is an
explosive oil (J. pr. Ch. [2] 62, 194).
Nitrite of Glutaric Acid, Trimethylene Cyanide, CH2<£**2<£^, m.p. -29°,
b.p. 286° (C. 1901. II. 807), is obtained from trimethylene bromide and potassium
cyanide. Alcohol and sodium convert it into pentamethylene diamine (p. 334)
and piperidine (p. 336), whilst it yields glutarimide dioxime with hydroxylamine
(B. 24, 3431).
fi-Chloro glutaric Acid is obtained from /?-hydroxy glutaric acid. Diethyi-
aniline converts it into glutaconic acid (p. 326) (C. 1905, I. 1225).
Pentachloroglutaric Acid, CO2H.CC12CHC1CC12.CO2H (B. 25, 2219).
a-Bromo- and a-Iodo-glutaric Ester are converted by KOH or diethyl aniline
into trimethylene dicarboxylic acid (comp. p. 507) (C. 1905, I. 1225).
ay-Dibromoglutaric Acid, CH2(CHBrCOOH)2, cis-iorm, m.p. 170° ; trans-
form, m.p. 143° with decomposition (comp. p. 503, ay-di-alkyl glutaric acids)
result when glutaric acid is brominated, and by the oxidation of cis- and trans-
dibromides of cyclopentadiene (Vol. II.). Reduction converts them into glutaric
acid, whilst afi-Dibromoglutaric, the dibromide of glutaconic acid (p. 520),
yields glutaconic acid when reduced (A. 314, 307, 509).
Mono-alkyl Glutaric Acids.— a-Methyl Glutaric Acid, C
m.p. 76°, results from the reduction of saccharone, and on treating camphor-
phorone with KMnO4 (B. 25, 265). It may be synthesized from methyl aceto-
acetic ester and /?-iodopropionic acid ; and when KNC acts on laevulinic acid.
It is a by-product in the decomposition of isobutylene tricarboxylic ester, the
condensation product of bromisobutyric ester and alcoholic sodium malonate
(see below). A series of a-alkyl glutaric acid are formed by the decomposition
of the alkylated i,i,3-propane tricarboxylic esters (C. 1901, I. 302), a-Methyl
glutaric acid and P2S6 yield $-M ethyl Penthiophen; anhydride, m.p. 40°, b.p. 283° ;
anilic acid (A. 292, 211); dinitrile, a-methyl trimethylene cyanide, b.p. 270°, is
prepared from dibromobutane and KNC (C. 1902, II. 1097).
a-Ethyl Glutaric Acid, m.p. 60°, b.p.80 1905; anhydride, b.p. 275°; anilic
acid (A. 292, 144, 215).
^-Methyl Glutaric Acid, EthylideneDiaceticAcid, CH3CH(CH2CO2H)2, m.p. 86',
is formed from crotonic ester and sodium malonic ester or sodium cyanacetic
ester (C. 1906, I. 186) ; also from ethylidene dimalonic acid ; anhydride, m.p. 46°,
b.p. 283° (B. 24, 2888). fi-Ethyl Glutaric Acid, Propylidene Diacetic Acid, m.p. 67°,
is prepared from propylidene dimalonic acid. fi-Isopropyl Glutaric Acid, m.p.
ALKYL GLUTARIC ACIDS 503
ioo6, in formed from a-cyano-/J-isopropyl glutaric mono-ester or /?-isopropyl
glutaric ester, whose methyl-substitution product yields a-methyl fi-isopropyl
glutaric acid (B. 38, 947). The /3-isopropyl glutaric acid, when oxidized with
CrO3, is converted into terpenylic acid (p. 558); but KMnO4 produces terebic
acid (p. 558) (C. 1899, I. 1157 ; 1900, II. 39, 467). The dinitriles of the j8-alkyl
glutaric acids are obtained also by boiling with water the oximes of alkylidene
bis-pyroracemic acids (diketopimelic acids, RCH[CHaC(NOH)COOH]a (C.
1906, I. 1105).
Di- and Tri-alkyl Glutaric Acids are produced together with tri- and tetra-
methyl succinic acids in the syntheses of these latter acids from a-bromiso-
butyric acid with silver, with methyl malonic ester, etc. In order to explain the
formation of these unexpected alkyl glutaric acids in these reactions, it has been
assumed that a portion of the a-bromisobutyric acid gives up HBr and passes into
methacrylic ester. In the silver reaction the HBr attaches itself to the methyl
acrylic ester, and the silver withdraws bromine from the a- and /8-bromisobutyric
esters, whereby the residues unite to trimethyl glutaric ester (B. 22, 48, 60) :
prr —HBr PTT -fHBf PTT -R_
C1HsOOC.CBr<££ - > C2H6OOC.C<~£3 - > CaH6OOC.CH<~gal
In the second stage sodium methyl malonic ester attaches itself to methyl
acrylic ester, and when the addition product is saponified it yields dimethyl
glutaric acid (B. 24, 1041, 1923) :
The aat- (or ay-) and ajS-dialkyl glutaric acids, similarly to the sym.-dialkyl
succinic acids (p. 494), exist in two modifications — the para- and meso-, or cis-
and tows-forms. The cis- acids are easily converted into anhydrides and imides,
whilst the tows-acids undergo these changes with difficulty or not at all (comp.
C. 1903, I. 389, etc.).
aai-Dimelhyl Glutaric Acid, CH2[CH(CH3)CO2H]2, m.p. cis- acid, 127°, trans-
acid 140° (A. 292, 146 ; B. 29, R. 421), are also prepared from CHaI2 and sodium
a-cyanopropionic ester. The cis-acid can also be obtained by reduction of
aa-dimethyl glutaconic acid (p. 521 ) by means of HI and phosphorus, accompanied
by the wandering of a methyl group (C. 1903, I. 697).
Bromine converts both acids into a-bromo-derivatives, from which hydroxy-
dimethyl glutaric acids and their lactones are obtained (B. 25, 3221 ; A. 292, 146).
Acetyl chloride or acetic anhydride convert the cis- acid into its anhydride, m.p.
94*, whilst the trans-acid is not changed when gently warmed (B. 31, 2112).
aa-Dimethy I Glutaric Acids,m.ps. 120° and 94°, are formed when/J-hydroxy-diethyl-
glutaric acid is reduced with HI (C. 1902, II. 107). On heating the barium salts
of aa-dimethyl and -diethyl glutaric acids there result dimethyl tetramethylene
ketone and diethyl tetramethylene ketone (C. 1897, II. 342). aa^-Methyl Iso-
butyl Glutaric Acids, m.ps. 121° and 78°, are produced from sodium isobutyl
malonic ester and bromisobutyl ester, etc. (C. 1900, II. 368).
afi-pimrtkyl Glutaric Acids, CO2H.CH(CH3)CH(CH,)CH2CO2H, tows-acid
fluid, cts-acid, m.p. 87°, are formed by hydrolysis and splitting off of COa from
the condensation products of crotonic ester, sodium cyanacetic ester and
iodomethane ; also of angelic or tiglic esters (p. 298) and sodium cyanacetic
ester (C. 1903, 1. 565, 1122 ; 1906, 1. 186 ; comp. also A. 292, 147 ; B. 29, 2058).
unsym.-aa-Dimethyl Glutaric Acid CO2H.C(CHs)aCH2CH2Cp2H, m.p. 85°;
anhydride, m.p. 38°, is prepared from y -chlorisobutyl acetic acid and potassium
cyanide (C. 1898, II. 963 ; comp. C. 1902, II. 25) ; by reduction of the addition
product of HI to aa-dimethyl glutaconic acid by means of zinc and hydrochloric
acid ; also by oxidation of camphor compounds (Vol. II.) (C. 1900, II. 282).
Treatment of aa-dimethyl glutaric anhydride with A12C16 in chloroform leads to
a partial production of isocaprolactone and pyroterebic acid and COa (comp.
unsym.-dimethyl succinic anhydride (p. 496) ; also C. 1902, 1. 567).
504 ORGANIC CHEMISTRY
ftp-Dimethyl Glutaric Acid, CO2H.CH2C(CH?)2CH2CO2H, m.p. 104° ; an
ide, m.p. 124°, is prepared from dimethyl acrylic ester with sodium or potassi
anhy-
dride, m.p. 124°, is prepared from dimethyl acrylic ester with sodium or potassium
malonic ester with subsequent decomposition of the dimethyl propane tricarboxylic
ester which is formed (A. 292, 145 ; C. 1897, I. 28) ; by decomposition of jSjS-di-
methyl propane tetracarboxylic ester (C. 1899, I. 926), of j8/?-dimethyl aardi-
cyanoglutaric ester or imide" (C. 1901, I. 821) ; also by oxidation, by means of
KBrO, of dimethyl hydroresorcinol (Vol. II.) (C. 1906, II. 18 ; B. 32, 1879) ; anilic
acid, m.p. 174°. Bromo-jSjS-dimethyl glutaric ester and alcoholic potassium
hydroxide yield the two caronic acids (Vol. II.). fifi-M ethyl Ethyl Glutaric Acid,
m.p. 87°. ftp-Methyl Propyl Glutaric Acid, m.p. 92°. pp-Methyl Butyl Glutaric
Acid, m.p. 65°. BB-Diethyl Glutaric Acid, m.p. 108° (see C. 1901, I. 821).
aaa^Trimethyl Glutaric Acid, CO2H2CH(CHS)CH2C(CH8)2CO2H, m.p. 97°
(comp. Tetramethyl Succinic Acid) ; anhydride, m.p. 96°, b.p. 262° (A. 292, 220,
C. 1906, II. 422). afip-Trimethyl Glutaric Acid, m.p. 88°, is obtained from cam-
phoric acid (Vol. II.), and a-cyano-oSS-trimethyl glutaric ester; anhydride, m.p.
82° (C. 1899, I. 522); a-cyano-aa,j3p-tetramethyl glutaric ester, produced by
methylating a-cyano-aj8/?-trimethyl glutaric ester, yields the aa^ft-Tetra-
methyl Glutaric Acids, CO2H.CH(CH,)C(CH3)2CH(CH8)CO2H, m.p. 140° and 90°
(C. 1900, II. 466).
aaa^-Tetramethyl Glutaric Acid, CH2[C(CH3)2COOH]2, m.p. 186°, is pro-
duced from/J-hydroxy-tetramethyl-glutaric acid by HI (C. 1900, II. 529).
GROUP OF ADIPIC ACID AND HIGHER NORMAL PARAFFIN
DICARBOXYLIC ACIDS
Adipic acid, CO2H[CH2]4C02H, and its alkyl derivatives volatilize
under reduced pressure without decomposition. They, together with
normal pimelic acid and suberic acid, are characterized by the fact
(i) that when their calcium salts are heated cyclic ketones result (J
Wislicenus, A. 275, 309) :
CHa— CH2— COOH CH2— CH2
CH,— CHa— COOH CH2— CH2
Adipic Acid. Adipic Ketone [Cyclopentanonejl
CH2— CH2— CH2.COOH CH2— CH2— CHa
CHa— CH2— COOH CH2— CH2— CO
n-Pimelic Acid. Pimelic Ketone [CyclohexanoneJ.
CHa— CHa— CH2COOH CH2— CH2— CH2
CH,— CH2— CH2.COOH CH£— CH2— CH-T
Suberic Acid. Suberone [Cycloheptanone].
CHa— CHj— CH2— CH2COOH CH2— CH2— CH2— CHt
CHa— CHa— CH2.COOH CHa— CH2— CH2— CO
Arelaic Acid. Azelaic Ketone [Cyclo-octanone].
CHa— CHS— CHa—CH2COOH > CH2— CH2— CH2— CH.
CHi— CH2— CH2— CH,COOH CH2— CH2— CH2— CH8>(
Sebacic Acid. Sebacic Ketone [Cyclononanone].
(2) Cyclic Condensation can also be brought about by the action of sodium or
sodium amide on the esters of adipic, pimelic acid, and, to a lesser extent, suberic
acid ; &-keto-cycloparaffin carboxylic esters are formed having the general formula
xCO
(CH,)n<M . Like acetoacetic ester, the CH-group can be alkylated by
CHCO2R
C2H8ONa and alkyl iodides, but when boiled with alcoholic sodium alcoholate the
ring becomes broken, reforming the dicarboxylic esters. These reactions provide
ADIPIC ACID
505
a method for alkylating adipic and pimelic acids in the a-position (A. 317, 27;
comp. C. 1905, II. 31 ; 1908, I. 1169), e.g. —
ROCO
CH2.CH,
ROCO.CH2.CH2
ROCOCH.(CH3).CHa
CH(CH3).CHa
ROCO-
ROCO
I
/CH.CH2
O/ |
\CH2.CH2
ROCO
I
/C(CH3).CHa
O/ |
XCH2 - CH2
ROCO.CH(CH3).CHa
I
CH2.CHa
>• |
ROCO
C(CH3)— CH,
ROCO
t /CH(CH3).CH,
co<
XCH CHa
ROCO
(3) Adipic acid and the higher normal paraffin dicarboxylic acids, similarly
to succinic acid, tend to form anhydrides when boiled with acetyl chloride or
acetic anhydride. The resulting bodies probably do not consist of single mole-
cules, but are multiples of them (B. 27, R. 1105 ; C. 1896, II. 1091 ; 1907, I. 964)
(comp. also the anhydrides of dialkyl malonic acids, p. 491 ).
The anhydrides obtained from adipic and pimelic acids and their alkyl sub-
stitution products by boiling with acetic anhydride, decompose when distilled
into CO a and cycloketones (C. 1907, II. 685) : —
CH3CH.CH2.CO v
I Sot?)
CH2.CH2.CO/
(CH3)2C— CH2.CH2.CO
I I (?)
CH2.CH2.COO
CH3CH.CH, x
I >co
CHj.CH/
(CH,)2C— CHa.CHt
Ha.CHa.CO
I
C
Adipic Acid [Hexane Di-acid], CO2H.[CH2]4CO2H, m.p. 148°, b.p.10 205-5°,
was first obtained by the oxidation of fats (adeps=fat) by nitric acid. It can also
be formed by the oxidation of cyclohexane, and particularly by oxidation of
cyclohexanone or cyclohexanol, the products of reaction of phenol (Vol. II.) and
alkaline potassium permanganate (B. 39, 2202 ; 41, 575). It can be prepared
(i) by reduction of hydromuconic acid (p. 522) ; (2) synthetically, from j8-iodo-
propionic acid and silver at 130-140°, or copper at 160° (B. 28, R. 466) ; (3) from
ethyl potassium succinate, by electrolysis (A. 261, 177) ; (4) from ethylene
dimalonic acid or butane tetracarboxylic acid ; (5) by hydrolysis and splitting
of y-cyanopropyl malonic ester or of tetramethylene dicyanide (C. 1901, I. 218,
610 ; II. 807).
The action of sodium converts adipic ester into jS-ketopentamethylene
monocarboxylic acid ester. Distillation of the calcium salt or anhydride results
in the production of cyclopentanone (p. 504). Amide, m.p. 222° (B. 32, 1772).
Adipic Dinitrile, Tetramethylene Dicyanide, m.p. i°, b.p. 295°, is formed from tetra-
methylene bromide or iodide and KNC (C. 1901, 1. 610 ; II. 807).
a-M ethyl Adipic Acid, m.p. 64°. a-Ethyl Adipic Acid is a liquid. j9 -Methyl
Adipic Acid, m.p. 89°, b.p.l4 211°. It results from the oxidation of pule-
gone and menthone (A. 292, 148); ethyl ester, b.p.16 138° [a]D +2-24°. Con-
densation of the ester (see above) to methyl cyclopentanone carboxylic ester is
accompanied by a great increase in the optical rotation to [o]D +78'240 (C. 1905,
II. 31), a-lsopropy I Adipic Acid, m.p. 67°, b.p.ia 222° (C. 1908, I. 1169, 1616).
Dialkyl Adipic Acids are obtained (i)from cyclopentanone carboxylic esters,
by alkylation and breaking of the ring (see p. 504) ; (2) from ethylene bis-alkyl
malonic esters; (3) from lactones or the bromo-fatty acids corresponding with
them, by the action of KNC or sodium malonic ester or sodium cyanacetic ester
(comp. p. 477) (C. 1907, II. 897; 1908, I. 1616) ; (4) by oxidation of hydro-
aromatic ketones (Vol. II.) ; a8 -Dimethyl Adipic Acid, two modifications, m.ps.
143° and 76° ; dinitriles are produced from the two 2,5-dibromohexanes (p. 323),
by KNC (B. 34, 807). aa-Dimethyl Adipic Acid, m.p. 90°. pp-Dimethyl Adipic
Acid, m.p. 87° (C. 1905, I. 26 ; 1907, I. 239 ; 1908, I. 1616). ay-Dimethyl
Adipic Acid, m.p. 80°. a-Ethyl '/-Methyl Adipic Acid, m.p. 98°. a§-Methyl
ropyl Adipic Acid, m.p, 111°, etc.
506 ORGANIC CHEMISTRY
Normal Pimelic Acid [Heptane Diacid], CO2H[CH2]6COaH, m.p. 105° (A. 292,
150), was first prepared by oxidizing suberone ; and from salicylic acid by the
action of sodium inamyl alcohol solution; cyclohexanone results as an intermediate
product, and the ring is broken according to the formulae on p. 505 (A. 286, 259) ;
by heating furonic acid, C7H8O6, with HI ; and in the oxidation of fats with nitric
acid. It can be obtained synthetically from trimethylene bromide and malonic
ester by heating pentamethylene tetracarboxylic acid, which is the first product
of the reaction (B. 26, 709). It may be conveniently prepared from the dinitrile,
Pentamethylene Dicyanide, b.p.12 172°. This is obtained from crude dichloro-
pentane (pp. 321, 323), and KNC (B. 37, 3588 ; C. 1904, II. 587). When its
calcium salt is distilled pimelic ketone [cyclohexanone] is produced (p. 504).
Alkyl Pimelic Acids : a-, /?-, and y-Methyl Pimelic Acids, m.p. 54°, 49°, and
56°. They are formed when the -o, m-, and p-cresotic acids (Vol. II.), or better
their dibromo-derivatives, are reduced by amyl alcohol and sodium (A. 295, 173).
The a-acid may also be prepared from the corresponding tetracarboxylic acid
(B. 29, 729), and by acid decomposition of methyl ketohexamethylene carboxylic
ester (p. 504).
aa^Dimethyl Pimelic Acids, m.p. 81° and 76° (B. 28, R. 465).
apa-Trimethyl Pimelic Acid, b.p.15 214° (B. 28, 2943).
f}p-Dimethyl Pimelic Acid, m.p. 104°, and ^a^-Trimethyl Pimelic Acid,
m-P- 55°. are prepared from the condensation products of S-bromo-jS-dimethyl
caproic ester and sodium malonic ester and sodium methyl malonic acid respec-
tively. The anhydrides of these acids yield on distillation dimethyl cyclohexanone
and trimethyl cyclohexanone (p. 505) (C. 1906, 1. 1819 ; 1907, 1.964).
aa^-Dibromopimelic Acid, m.p. 141° ; diethyl ester, b.p.28 224°, when acted
on by sodium ethoxide becomes A'-cyclopentene dicarboxylic acid (Vol. II.).
Suberic Acid [Octane Diacid], c62H[CH2],CO2H, m.p. 140°, is obtained by
boiling cork (B. 26, 3089), or fatty oils, with nitric acid (B. 26, R. 814). Its
ethyl ester, b.p. 280-282°, has been synthesized by electrolyzing potassium ethyl
glutarate ; it is also obtained by the action of magnesium and COa on trimethylene
bromide (p. 322) (B. 40, 3039). Distillation of the calcium salt produces suberone
(p. 504) (A. 275, 356) ; anhydride, m.p. 62° ; diamide, m.p. 216° (B. 31, 2344) ;
dihydrazide, m.p. 185°; diazide, m.p. 25°. See also i,6-hexamethylene diamine
(P- 334) (J- pr- Ch. [2] 62, 198). fifi^Tetramethyl Suberic Acid, [HOOC.CH2C-
(CH3)2.CH2]2, m.p. 165°, is produced from j8-dimethyl glutaric mono-ester, by
electrolysis (C. 1906, II. 18).
Higher Parafiin-dicarboxylic Acids result, accompanied by oxalic, succinic and
suberic acids, when fatty and oleic acids are oxidized by nitric acid.
The higher acetylene carboxylic acids (p. 304) usually decompose into the
acids CnH2/lO4, when oxidized with fuming nitric acid. The mixture of acids that
results is separated by fractional crystallization from ether ; the higher members,
being less soluble, separate out first (B. 14, 560). Such acids have also been
produced by the breaking-down of ketoximic acids through the action of con-
centrated sulphuric acid, e.g., sebacic acid from ketoxime stearic acid (p. 300).
Lepargylic Acid, Azelaic Acid [Nonane Diacid], CO2H[CH2]7CO2H, m.p.
1 06°, is obtained by the oxidation of oleic acid and castor oil by nitric acid or per-
manganate (B. 17, 2214 ; C. 1900, I. 250). The name is derived from azotic
acid=nitric acid, and elaidic acid, connected with oleic acid. It is synthetically
prepared from pentamethylene bromide and sodium acetoacetic ester (B. 26,
2249). When distilled with lime it yields azelaone (p. 504) ; ethyl ester, b.p. 291°
(A. 307, 375) ; anhydride, m.p. 52° ; nitrile, b.p.21 195° (C. 1898, II. 848). Azelaic
Dithiolic acid, COSH[CH2]7COSH, m.p. 73°, is formed when azelaic diphenyl ester
is " hydrolyzed " by NaSH. Sodium converts it into a disulphide, [CHa]7[COa]S2
(C. 1905,11.217).
Sebacic Acid [Decane Di-acid],CO2H[CH2]8CO2H, m.p. 133°, is formed (i) by
dry distillation of oleic acid ; (2) by oxidation of stearic acid, spermaceti or castor
oil by nitric acid ; (3) from stearyl ketoxime ; (4) from heptane tetracar-
boxylic acid (B. 27, R. 413). Anhydride, m.p. 78°; diethyl ester, b.p.20 196°;
XONH
dihydrazide, m.p. 185° ; diazide, m.p. 34°. sym.-Sebacic Hydroxide [CH,]8<f
XCONH
m.p. 142° (J. pr. Ch. [2] 62, 216).
OLEFINE DICARBOXYLIC ACIDS 507
Nonane Dicarboxylic Acid [CH2]9(CpOH)?, m.p. 110°, is obtained from w-hydro-
xyundecylic acid (p. 375) by oxidation with CrO3. Deceive Dicarboxylic Acid
[CH2]10(COOH)2, m.p. 127°, is prepared from co-brorno-undecylic acid and KNC;
also synthetically by electrolysis of pimelic mono-ester (B. 34, 900 ; C. 1901,
II. 1046).
Brassylic Acid [CH2]n(CO2H)2, m.p. 114°, is obtained by oxidation of behenolic
acid and erucic acid (B. 26, 639, R. 705, 811). It is synthetically prepared by
condensing a;-bromo-undecylic ester and sodium malonic ester in alcohol, and
subsequently hydrolysing and decomposing the condensation product. On the
simultaneous formation of an isomeric acid (possibly a-Methyl Decane Dicar-
boxylic Acid], m.p. 82°, see B. 34, 893 (comp. C. 1901, II. 1046).
Roccettic Acid, C17H32O4, m.p. 132°, occurs free in nature in Roccella tinctoria.
B. OLEFINE DICARBOXYLIC ACIDS, CnH2n-4O4
The acids of this series bear the same relation to those of the oxalic
acid series that the acids of the acrylic series bear to the fatty acids.
The free acid hydrates of all the acids of the oxalic series are
known, but in the case of the unsaturated acids there are some, like
carbonic acid, which only exist in the anhydride condition. When
the attempt is made to liberate the acids from their salts, they imme-
diately split off water and pass into the corresponding anhydrides,
e.g. dimethyl and diethyl malei'c anhydrides. The analogy of such
acids with carbonic acid, to which reference has already been made
(p. 307), shows itself in the following constitutional formulae (A.
254, 169 ; 259, 137) :—
— ONa ^°=C<OHJ- ->0=C=0+HtO
/ONa / /OH\
CH3.C— C^-ONa / CH3.C— C(-OH \ CH3.C— C==O
CH.3C— C=0 \CH3.C— C=0 / CH3.C— C=0
Sodium Pyrocinchonate Pyrocinchonic Acid Pyrocinchonic An-
or Dimethyl Maleate. (does not exist). hydride.
Hence, dimethyl and diethyl malei'c acids cannot contain two
carboxyl groups any more than carbonic acid can contain them.
Even in the salts and esters a y-lactone ring would be present. The
hypothetical acid hydrates would be unsaturated y-dihydroxy-
lactones.
The cycloparamn dicarboxylic acids, having a like carbon content and isomeric
with the unsaturated dicarboxylic acids, will be discussed after the cycloparafnns,
e.g. :
Trimethylene Dicarboxylic Acid, \ >C(COaH)f
CH/
KCHa— CHCOaH
etramethylene Dicarboxylic Acid, \
CHa— CHCOaH
>CH2CHC08H
mtamethylene Dicarboxylic Acid, CH2<T
\:H2CHCO2H.
Jhe lowest member of the series has two possible structural iso-
mers : meihylene • malonic acid, CH2 : C(CO2H)2, and ethylene di-
'boxylic acid, CO2HCH:CH.CO2H. The first is" only known in the
5o8 ORGANIC CHEMISTRY
form of its ester. However, there are two acids, fumaric and maleic
acids, which it is customary to regard as different modifications of
ethylene dicarboxylic acid.
(a) Alkylidcne Malonic Acids.
Methylene Malonic Ester, CH2=C(CO2C2H5)2, is produced when i molecule
of methylene iodide and 2 molecules of sodium ethoxide act on t molecule
of malonic ethyl ester (together with p-ethoxyisosuccinic ester, C2H6O.CHaCH-
(CO2R)2 (B. 23, R. 194 ', 22, 3294 ; A. 273, 43). Under diminished pressure it
distils as a mobile, badly-smelling oil. If allowed to stand, it soon changes into
a white, solid mass, (C8Hi2O4)2 (C. 1898, II. 1169). The liquid ester unites with
bromine. See also j3-Hydroxyisosuccinic Acid, p. 550.
Ethylidene Malonic Ester, CH3CH:C(CO2C2H6), b.p.17 116°, is formed when
acetaldehyde is condensed with malonic ester by acetic anhydride (A. 218, 145).
Malonic ester combines with it to form ethylidene dimalonic ester. Hydrolysis
with barium hydroxide solution converts it into a hydroxy-carboxylic acid,
C8H6(OH)(CO2H)2. Trichlorethylidene Malonic Ester, CC13CH : C(CO2C2H6)2, b.p.,,
1 60°, results when chloral and malonic ester are condensed by acetic anhydride
(A. 218, 145). Isoprofylidene Malonic Acid, (CH3)2C : C(CO2Ha), m.p. 170';
ethyl ester, b.p.i20 176°, is formed from malonic ester and acetone by the action of
acetic anhydride (B. 28, 785, 1122, comp. B. 34, 1955).
Cyanacetic ester, reacting with aldehydes in the presence ot sodium ethoxide,
gives rise to olefine nitrile esters, such as ethylidene cyanacetic ester, CHSCH:C-
(CN)CO2R (C. 1901, I. 1271 ; comp. C. 1898, I. 664). Cyanacetic ester con-
densed with acetone by diethylamine, is converted into Isopropylidene Cyan-
acetic Ester, (CH8)2C : C(CN)CO2C2H6, m.p. 28° (B. 33, 3530; C. 1905, II. 726).
Allyl Malonic Acid, CH2:CH.CH2CH(CO2H)2> m.p. 103°, is obtained from
malonic ester by means of allyl iodide. It crystallizes in prisms (A. 216, 52).
Compare y -Valerolactone, p. 374, and Carbovalerolactonic Acid, p. 551. See
B. 29, 1856, and C. 1905, II. 660, for Ethyl Ally I Malonic Acid and its homologues.
(b) TTnsaturated Dicarboxylic Acids, in which the carboxyl groups
are attached to two carbon atoms.
Formation. — They can be obtained, like the acrylic acids, from the
saturated dicarboxylic acids by the withdrawal of two hydrogen atoms.
This is effected (i) by acting on the monobromo-derivatives with
alkalis :
— HBr
C2H,Br(C02H)2 > C2H2(CO2H)a;
Bromosuccinic Acid. Fumaric Acid.
(2) by allowing potassium iodide to act on the dibromo-derivatives
(p. 500). Thus, fumaric acid is formed from both dibromo- and iso-
dibromo-succinic acids :
C,H1Br1(COtH)a+2KI=C1H,(COtH)t+2KBr+I1;
and mesaconic acid, C3H4(CO2H)2, from citra- and mesa-dibromo-
pyrotartaric acids, C3H4Br2(CO2H)2. As a general rule the unsaturated
acids are obtained (3) from the hydroxydicarboxylic acids by the
elimination of water (p. 509).
Behaviour. — The acids of this series show the same tendency to
addition reactions as was observed with the unsaturated monocar-
boxylic acids. Thus (i) hydrogen causes them to revert to saturated
dicarboxylic acids ; (2) halogen acids (particularly HBr) and (3) halo-
gens convert them into haloid saturated dicarboxylic acids. (4) When
heated with potassium hydroxide an addition of hydrogen occurs with
the production of monohydroxy-saturated dicarboxylic acids ; others,
again, are molecularly rearranged (B. 26, 2082). Such rearrangement
FUMARIC ACID 509
among isomers has been induced by boiling water or acids (comp.
fumaric and maleic acids, mesaconic, citraconic and itaconic acids).
(5) Potassium permanganate oxidizes some of the unsaturated di-
carboxylic acids to dihydroxy-dicarboxylic acids of the paraffin series.
(6) Amino- and substituted amino-dicarboxylic acids of the saturated
series have been obtained by the addition of ammonia, anih'ne and other
bases.
(7) The acids of this series combine with diazomethane or diazoacetic acid,
yielding pyrazoline derivatives (A. 273, 214 ; B. 27, 868), which pass into trime-
thylene derivatives by the elimination of nitrogen (p. 404) :
ROCOCH ROCOCH— CH^C02R . ROCOCH— CHCOOR
n +N.CHCO.R — > i VNT — >• i ^
ROCOCH ROCOCH N^^ ROCOCH^
Fumaric and maleic acids, the first members of this series, are by
far the most important acids of their class.
Fumaric Acid, C2H2(C02H)2, occurs free in many plants, in
Iceland moss, in Fumaria officinalis, and in some fungi. It is formed
(1) when inactive and active malic acid are heated (water and maleic
anhydride are also produced) (B. 12, 2281 ; 18, 676), and by boiling
malic acid with sodium hydroxide solution (B. 33, 1453) ; (2) by boiling
the aqueous solutions of monochloro- and monobromo-succinic acids ;
(3) by heating dibromo- and isodibromo-succinic acids with a solu-
tion of potassium iodide ; (4) synthetically from dichlor- or dibrom-
acetic acid and silver malonate ; also from glyoxylic acid and malonic
acid by heating them with pyridine (B. 34, 53) ; (5) from maleic acid
(see the conversion of fumaric and maleic acids into each other, p. 511) ;
and fumaric acid is obtained by boiling with water bromosuccinyl
bromide, the reaction product of phosphorus and bromine on succinic
acid (B. 23, 3757).
Properties. — It is almost insoluble in cold water, but crystallizes
from hot water in small, striated prisms. It sublimes at 200°, and at
higher temperatures decomposes, forming maleic anhydride and water.
Salts. — The silver salt, C4H2O4Aga, is very insoluble ; it is fairly stable under
the influence of light ; barium salt, C4H2O4Ba+3H2O, consists of prismatic
crystals, which effloresce and when boiled with water change to C4HaO4Ba — a
salt that is practically insoluble in water.
Esters — The fumaric esters are formed (i ) from the silver salt and alkyl iodides ;
(2) from fumaric acid, alcohols and hydrochloric acid ; (3) from the esters of mono-
bromosuccinic acid by the action of pyridine or quinoline (C. 1905, I. 25) ; by the
slow distillation of malic and acetyl malic esters (B. 22, R. 813) ; (4) from maleic
esters (see interchange between fumaric and maleic acids, p. 511) ; (5) by heating
diaxoacetic esters (B. 29, 763).
The methyl ester, C2H2(CO2CH3)2, m.p. 102°, b.p. 192° ; ethyl ester, b.p. 218°
(B. 12, 2283). Bromine unites with fumaric esters to form dibromosuccinic esters.
Many other substances have the power of adding themselves to them, e.g.
sodium acetoacetic ester, sodium malonic ester (B. 24, 309, 2887, R. 636), sodium
cyanacetic ester (B. 25, R. 579), diazoacetic ester (above) phenyl azoimide, etc.
Fumaryl Chloride, COC1.CH:CH.COC1, b.p. 160°, is produced when PC15
acts on fumaric acid (B. 18, 1947 ; C. 1906, II. 19). Bromine converts it into
dibromosuccinyl chloride (A. Suppl. 2, 86) ; and with sodium peroxide it yields
Fumaric Peroxide, C4H2O4, a white powder, exploding at 80° (B. 29, 1726).
Fumaramic Acid, CONH2.CH:CH.CO8H, m.p. 217°. is formed when aspara-
gine is acted on by methyl iodide and potassium hydroxide (A. 259, 137).
Fumaramide, CONHaCH=CH.CONH8, m.p. 266° (B. 25, 643).
510 ORGANIC CHEMISTRY
Fumarhydrazide, NH2NH.CO.CH:CH.CO.NHNHa, m.p. 220°, with de-
composition. Fumarazide, N8CO.CH:CH.CON8, is crystalline. It explodes
easily and when boiled with alcohol yields Fumarethyl Urethanc, ROCONHCH:-
CHNHCOOR (B. 29, R. 231).
Fumaranilic Acid, C6H6NH.COCH=CH.CO2H, ra.p. 231°, is formed from the
corresponding chloride and water. Fumaranilic Chloride, C6H6NH.CO.CH =
CH.COC1, m.p. 120°, crystallizes from ether in transparent, strongly refracting,
sulphur-yellow coloured prismatic needles or plates. It is produced when aniline
acts on fumaryl chloride in excess. . Fumardianilide, C6H5NHCOCH=»
CHCONHC,H5, m.p. 234°, with decomposition (A. 239, 144 ; C. 1906, II. 19).
Malei'c Acid, C4H4O4, m.p. 130°, b.p. 160° with decomposition
into malei'c anhydride and water. Its anhydride is formed as men-
tioned under fumaric acid :
(1) By the rapid heating of malic acid.
(2) In the slow distillation of monochloro- and monobromosuccinic
acid, as well as acetyl malic anhydride at the ordinary pressure.
(3) By the action of PC15 on malic acid (A. 280, 216).
(4) Malei'c acid is formed synthetically, in small amount, when
silver or sodium acts on dichloracetic acid and dichloracetic ester.
(5) Maleic acid is obtained on decomposing trichlorophenomalic
acid or j3-trichloracetyl acrylic acid (p. 425) with barium hydroxide
solution. Chloroform is produced at the same time.
(6) From quinone (Vol. II.) by oxidation with silver peroxide
(B. 39,3715):
CH.CO.CH CHCOOH
II II > II -f 2COf.
CH.CO.CH CHCOOH
(7) From fumaric acid (see transformations of fumaric and maleic
acids).
Properties. — Maleic acid crystallizes in large prisms or plates, is
very easily soluble in cold water, and possesses a peculiar, disagreeable
taste.
Salts. — C4H2O4Ag2 is a finely divided precipitate. It gradually
changes to large crystals. C4H204Ba -J-H20 is soluble in hot water,
and crystallizes well.
The esters result from the action of alkyl iodides on the silver
salt:
The methyl ester, C2Ht(CO8.CH,),, is a liquid, b.p. 205° ; ethyl ester, b.p. 225°.
When heated with iodine the}'- change for the most part into fumaric esters.
CHCO\
MaleYc Anhydride, II /O, m.p. 53°, b.p. 202°, is produced
(i) by distilling maleic or fumaric acid alone, or more readily (2) with
acetyl chloride or P2O5 (B. 37, 3722) ; (3) by the distillation of mono-
chloro- and monobromosuccinic acids, and also of acetomalic anhy-
dride (A. 254, 155) ; (4) when PC16, P206 and POC13 act on fumaric
acid (A. 268, 255). It is purified by crystallization from chloroform
(B. 12, 2281 ; 14, 2546). It consists of needles or prisms, having a
faintly penetrating odour. It regenerates maleic acid by union with
water, and forms isodibromosuccinic anhydride when heated with
bromine (comp. Asparagine, p. 554).
FUMARIC AND MALEIC ACIDS 511
Maleic Chloride (B. 18, 1947 ; C. 1906, II. 20).
CH.CONH, CHC(OH)NH,V
Makinamic Acid, \\ or || V), m.p. 153°. Its ammonium
CH.COOH CHCO /
salt results when ammonia acts on maleic anhydride. Aqueous potassium
hydroxide converts the acid into maleic acid, whereas fumaric acid results when it
is treated with alcoholic potassium hydroxide. Makinmethylamic Acid, m.p. 149"
(B. 29, R. 653).
Maleinimide, C,H2(CO)3NH, m.p. 93°, is produced when pyrrole is oxidised
by chromic acid mixture. It sublimes when heated (C. 1904, II. 305).
CH.CO.NHC4H5 CHC(OH)(NHC,H5K
Maleinanilic Acid, (| or || y>O. m.p. 187°,
CH.COOH CHCO /
is formed when aniline acts on an ethereal solution of maleic anhydride. Heated
under greatly reduced pressure it splits into maleic anhydride and aniline, which
reunite in the receiver to maleinanilic acid. Alcoholic potassium hydroxide and
barium hydroxide solution convert it into fumaric acid (A. 259, 137).
CHCOv
Maleinanil, 11 ;>NC.Hr, m.p. 91°, results upon heating aniline malate, in
CHCO'
the form of bright yellow needles. It combines readily with aniline, forming
phenyl asparaginanil (A. 239, 154). Maleindianilide, m.p. 175° (C. 1901, I. 171).
CH.C=N.NH,
Aminomaleinimide, \\ >O , m.p. 111°, is obtained from maleic
CH.CO
anhydride and hydrazine hydrate in alcohol. When its solution is heated it
CHCO.NH
changes to Malein Hydrazide, \\ \ , consisting of white crystals, which do not
CHCO.NH
melt at 250°. It is a strong acid.
BEHAVIOUR OF FUMARIC AND MALEiC ACIDS
1. Acetylene is formed when the alkali salts of these acids are clectrolyzed
(p. 86).
2. Sodium amalgam, or zinc, reduces them both to succinic acid.
3. When heated to 100° with sodium hydroxide both acids change to inactive
malic acid (A. 269, 76), whilst malic acid is changed into fumaric acid when boiled
with sodium hydroxide solution (p. 509).
4. Fumaric and maleic esters react with sodium alcoholates to form alkyl-
hydroxy-succinic acids (B. 18, R. 536).
5. Bromine converts :
Fumaric acid into dibromosuccinic acid.
Fumaric ester H dibromosuccinic ester.
Fumaryl chloride „ dibromosuccinyl chloride.
Maleic anhydride „ isodibromosuccinic anhydridt.
6. Potassium permanganate changes (B. 14, 713) :
Fumaric acid into racemic acid.
Maleic acid mesotartaric acid.
CONVERSION OF FUMARIC AND MALEIC ACIDS INTO EACH OTHER
1. When fumaric acid is heated, or treated with PC16, POC1, and P8O6 (A. 268,
255 ; 273, 31) it becomes converted maleic anhydride.
2. Maleic acid changes to fumaric acid :
(a) When it is heated alone in a sealed tube to 200° (B. 27, 1365).
(b) By the action of cold HC1, HBr, HI and other acids ; also SO2 and H2S
(B. 24, R. 823), HaO. (B. 33, 3241), as well as by the action of bromine in sunlight
(B. 29, R. jo8o)
512 ORGANIC CHEMISTRY
(c) On heating maleic ester with iodine fumaric esters result.
(d) Alcoholic potassium hydroxide changes maleinamic and maleinanilic acids
to fumaric acid.
THE ISOMERISM OF FUMARIC AND MALEiC ACIDS
The view generally acepted as to the cause of the isomerism of
these two acids was presented in the introduction, under the section
relating to the geometrical isomerism, the stereoisomerism of the
ethylene derivatives (p. 32). In conformity with this representation
we find in maleic acid, readily forming an anhydride, an atomic grouping
which follows the plane-symmetrical configuration, according to which
the carboxyl groups are so closely arranged with reference to each
other that the production of an anhydride follows without difficulty.
Fumaric acid is not capable of forming an anhydride, hence it has
the central or axial symmetrical structure.
These space-formulae satisfactorily represent the intimate con-
nection existing, as shown by Kekule and Anschiitz, between fumaric
and racemic acids, and maleic and inactive tartaric acids. According
to the van *t Hoff-Le Bel view of these four acids, the oxidation of
fumaric to racemic acid by means of potassium permanganate and
maleic to mesotartaric acid, may be shown by the following formulae,
which have a spacial significance (comp. p. 32) : —
C02H COaH
H— G— COaH H— *C— OH HO— *C— H
2 || +20+2H.O - | + ' J
CO2H— C— H HO— *C— H H— *C— OH
COaH C02H
Fumaric Acid. Dextro-tartaric Acid + Laevo-tartaric
Acid = Racemic Acid.
C02H
H— C— COaH H— *(^OH
|| +0+H.O « |
H— C— COaH H— *C— OH
C02H
Maleic Acid. Mesotartaric Acid.
The oxidation of the two acids, based on stereochemical formulae,
is so represented that upon severing the double linkage in fumaric
acid by the addition of hydroxyl groups an equal number of mole-
cules of dextro- and laevo-tartaric acid results, whilst by the rupture
of the double linkage in maleic acid only mesotartaric acid is formed.
Cognizant of this view, /. Wislicenus has sought to explain the conversion of
maleic into fumaric acid by hydrochloric acid in the following manner : In these
two acids the two doubly-linked carbon atoms cannot rotate independently of each
other, consequently not in opposite directions ; but when the double union is
removed by the addition of two univalent atoms, then free rotation at the single
bond can occur. Accordingly, /. Wislicenus' explanation proceeds, in his own
words, as follows : "On account of the extreme ease with which maleic acid,
in contrast to fumaric acid, lends itself to the formation of addition products
FUMARIC AND MALEIC ACIDS 513
(B. 12, 2282), it first absorbs the elements of the mineral acids (e.g., HC1), and
becomes converted into a substituted succinic acid, which, under the directing
influence of the greater affinities, assumes the preferred configuration (in which
similar groups are as far removed from each other as possible) by the rotation
of the one system in opposition to the other, and then by the loss of HC1, under
the influence partly of the water which is present and partly of the slight solubility
of fumaric acid, the latter acid must result."
HC1C02H
'
H
+ HCI C C -HCl C02H— C— H
CO2H C C H— C— CO3H
HCOaH H H COaH
Malelc Acid. Monochlorosuccinic Acid Fumaric Acid.
previous to after rotation
rotation in the preferred position.
Only that intermediate product, monochlorosuccinic acid, is known in the free
condition, which is in the preferred configuration. It is stable towards hydro-
chloric acid at 10°, and its anhydride unites with water to form the original acid,
instead of yielding fumaric acid, although in so doing the monochloroscuccinic
acid, as predicted by /. Wislicenus, in the conversion of maleic into fumaric acid
would change, through rotation, from the less favourable to the preferred con-
figuration (Anschutz, A. 254, 168). This is by no means the only fact with which
the preceding explanation of the mechanism of the reactions showing the conver-
sion of fumaric into maleic acid, and vice versa, clashes (comp. B. 20, 3306 ;
24, R. 822 ; 24, 3620; 25, R. 418 ; 26, R. 177 ; A. 259, i ; 280, 226 ; J. pr. Ch.
[2] 75, 105 ; see also Z. phys. Ch. 48, 40).
In the introduction to the unsaturated dicarboxylic acids it was shown that
at least some of these acids could only exist in the anhydride form, as their
hydratcd forms broke down, in the mo'ment of their liberation from salts, into
anhydrides and water. These acids, the dialkyl maleic acids (p. 518), are intimately
related to maleic acid. The monoalkyl acids (p. 516) are still capable of existing
in hydrate form, although they change more easily than maleic acid to their
anhydrides. Considering the analogy with carbonic acid, the salts of the dialkyl
maleic acids may be viewed as being derivatives of a hypothetical acid hydrate,
in which the two hydroxyl groups are attached to the same carbon atom, and this
view may be considered to prevail with maleic acid and with the monoalkyl
maleic acids, so similar to the dialkyl maleic acids. The assumption that fumaric
acid is symmetrical ethylene dicarboxylic acid and maleic acid the 7-dihydroxyl-
actone corresponding with this dicarboxylic acid in no wise renders a stereochemical
formulation of the two acids impossible. Probably the stereochemically different
arrangement and position, in the chemical structure, of the atoms contained in
acids, mutually influence each other (A. 254, 168) :
/OH
H.C.COOH H.C.C^-OH
CO2H.C.H H.CO
Fumaric Acid. M.lei'c Acid.
However, even this view, as yet, does not afford a satisfactory explanation of
the reactions by which these acids are converted into each other. Consult A. 239,
161, for the history of the isomerism of fumaric and maleic acids.
The various ideas as to the cause of the isomerism of fumaric and maleic
acids are connected with the question as to the nature of the double linkage
Finally, attention may be directed to the difference in the heat of combustion
of the acids. This would indicate that the energy present in the acids, in the form
of atomic motion, is markedly different. " This fact suggests the possibility that
the cause of the isomerism is not to be sought exclusively in the varying arrange-
ment of the atoms, nor in their different spacial positions, but also in the varying
VOL. I. 2 L
514 ORGANIC CHEMISTRY
magnitude of the motion of the atoms (or atom complexes) ." " It is also possible
to imagine a case in which the isomerism would only be influenced by the differ-
ence in energy content — a case in which there might be perfect similarity in linkage
and also in the spacial arrangement of the atoms."
In addition to structural and spacial isomerism, there is the hypothesis of
energy or dynamical isomerism (Tanatar, A. 273, 54 ; B. 11, 1027 ; 29, 1300), to
which this name is more applicable than to that to which attention has been
drawn in connection with the sym.-dialkyl succinic acids (p. 494)' Klinger
proposes the name " alloergatia " (from ergasia or ergatia) for that type of iso-
merism when molecules of the same weight and chemical construction contain
unequal quantities of energy (B. 32, 2194).
It is by no means established that fumaric acid is not a polymeric modification
of maleic acid. That their vapour densities are the same proves nothing on this
point, inasmuch as the vapour densities of racemic and tartaric esters are identical,
and yet the molecule of solid racemic acid consists of a molecule each of dextro-
and kevo-tartaric acids. The same remarks are true in regard to the results
obtained by the freezing-point depressions.
Haloid Fumaric and Maleic Acids
Monochlorofumaric Acid, C4H3C1O4, m.p. 192°, results (i) from
tartaric acid and PC16 or PC18 ; (2) from the two dichlorosuccinic
acids ; (3) from acetylene dicarboxylic acid and fuming nitric acid.
Monochloromdleic Acid, m.p. 106° ; anhydride, m.p. o° and 34°, b.p.760
197°, b.p.25 95°, is produced when acetyl chloride acts on chloro-
fumaric acid, and when isodichlorosuccinic anhydride is heated (A.
280, 222).
Monobromofumaric Acid, C4H3BrO4, m.p. 179°, is produced from acetylene
dicarbonic acid and HBr ; and from isodibromosuccinic acid and boiling water.
Monobromomaletc Acid, m.p. 128°, is formed when dibromosuccinic acid — the
addition product of bromine and fumaric acid — is boiled with water ; ester, b.p.ia
140°, is prepared from dibromosuccinic ester and quinoline (C. 1905, I. 26);
anhydride, b.p. 215°, is prepared by heating isodibromosuccinic anhydride and
dibromosuccinic acid, either alone or with acetic anhydride or acetyl chloride.
The action of HBr is to produce bromofumaric acid and some dibromosuccinic
acid. Monoiodofumaric acid, m.p. 183° (B. 15, 2697).
Dichloromaleic Acid, C4ClaHaO4, results when hexachloro-p-diketo-R-hexene>
CO<CC1 — CC1 >CO' and P*rrttor*cctyl acrylic acid, CCl3CO.CCl-CCl.COaH
(p. 425), are decomposed by sodium hydroxide (A. 267, 20 ; B. 25, 2230). On the
application of heat it passes into the anhydride, CaCl2(CO)2O, m.p. 120°. PC15
converts succinic chloride into two isomeric dichloromaleic chlorides (B. 18, R. 184 ;
C. 1900, I. 404). Its imide, C2C12(CO2)2NH, m.p. 179°, is obtained when succinimide
is heated in a current of chlorine. One molecule of PC16 changes the imide to
Dichloromaleinimide Chloride (i), m.p. 148°, which is also formed from PC16 and
succinimide. Aniline converts it into dichloromaleinimide anil (2), m.p. 152°.
Two molecules of PC18 transform dichloromaleinimide into pentachloropyrrole (3),
CC1— CC12X CC1C(NC6H5K CCla.CCk
(i) II >NH (2) || ^\NH (3) || >N
CC1— CO / CCLCO-^" CC1.CC1/
Dichloromalein Anil, C,Cla(CO)aNC,H,, m.p. 203*, is formed when dichloro-
malein anil chloride is boiled with glacial acetic acid or water.
Dichloromalein Anil Chloride, m.p. 124°, b.p.a 179°, is produced, together witr.
Tetrachloro-n-phenyl Pyrrole, m.p. 93°, on treating succinanil with PCI,. By re-
duction it yields S-anilidobutyrolactam (see Succinimide, p. 497). Alcohols
convert it into dialkyl esters: Dichloromalein Anil Dimethyl Ester, m.p. 110°,
wljilst with aniline it yields Dichloromalein Dianil, m.p. 187° (A. 295, 27) :
ITACONIC ACID 515
CH2.CO 4PC1, CCl.CCla H CH,— CH,
>NC.H§ > || >NC6H5 > | >NC,H.
CH2.CO i CC1.CO \ CH2— CO
Succinanil. Dichlormalemanil xv y-Anilidobutyro-
Chloride. >^ lactam.
™-rn Yrr.1:
CCL
CC1=CC1 YCCl.C(OCH3)a CC1.C
>N.C6Hf || >N.C,H6 || >NC8H6
CC1 CC1.CO CC1.CO
a-Phenyl Tetrachloropyrrole. Dichlormalem Anil Dichlormalem Dianil.
Dimethyl Ester.
Dibroinomaleie Acid, C2Br2(CO2H)2, m.p. 120-125°, is obtained by acting*
on succinic acid with Br (C. 1900, I. 404), or by the oxidation of mucobromic acid
with bromine water, silver oxide or nitric acid. It is very readily soluble, and
readily forms the anhydride, C2Br2(CO)2O, m.p. 115° (B. 13, 736). Chlorobromo-
maleic Acid, see B. 29, R. 186.
Dibromofumaric Acid, m.p. 219-222°, and di-iodofumaric acid, decomposes
at 192°, are addition products of bromine and iodine with acetylene dicarboxylic
acid (B. 12, 2213 ; 24, 4118). Chloriodofumaric Acid, m.p. 227° with decom-
position, unites with chlorine to form an iodosochloride (i) (comp. p. 135). It
reacts with alcohol, losing CO2 and forms chloracrylic acid iodosochloride (2) ;
which, with hot water, yields iodosochloracrylic acid (3) ; and finally this, with
glacial acetic acid to form iodosochloracrylic acid acetate (4) (B. 38, 2842) :
CIC—CO\ C1C— CC\
(i) II >0 > (2) H X> >
HOCOC.I(Cir HCI(CJ) '
C1C— CO v C1C CO.
(3) II >0 > (4) I! >O
HCI(OH)X HCI(OCOCH3K
Acids, C5H604=C3H4(CO2H)2. — Eight dicarboxylic acids, having
this formula, are known. There are four unsaturated acids isomeric
with ethylidene malonic acid described on p. 508 : (i) Itaconic acid,
(2) Citraconic acid, (3) Mesaconic acid, (4) Glutaconic acid, and three
trimethylene dicarboxylic acids. Mesaconic and citraconic acids bear
the same relation to each other as fumaric to maleic acid. They show
similar conversions of one into the other, which, however, occur less
readily than in the case of the latter acids (B. 27, R. 412). The in-
troduction of the methyl group very considerably increases the tendency
of citraconic acid to break down into its anhydride and water. This
takes place at 100° under diminished pressure (comp. Chloral Hydrate).
Mesaconic acid is more easily changed by acetyl chloride to citraconic
anhydride than fumaric acid to maleic anhydride. Furthermore,
maleic anhydride combines more readily, and therefore more rapidly,
with water than citraconic anhydride.
CH2=O-COOH
Itaeonic Acid, Methylene Succinic Acid, , m.p. 161°, is pro-
CH2.COOH
duced from its anhydride by combination with water ; or by heating citraconic
anhydride with 3 to 4 parts of water at 150°, whereby the citraconic anhydride is
first transformed into itaconic anhydride which is then converted into the acid.
It is not volatile in steam. Hydrogen converts it into pyrotartaric acid, and per-
manganate into hydroxyparaconic acid (q.v.) (A. 305, 41). When electrolyzed
it is decomposed into sym.-allylene or allene, CH2=C=CH3 (p. 90). When boiled
with aniline it forms pseudoitaconanilic acid, the lactam of y-anilinopyro-tartaric
acid (p. 556) (A. 254, 129). On the addition of HBr and Br2, see pp. 500, 501.
Itaconic Dimethyl Ester, m.p. 38°, b.p.n 108°, when not quite pure, poly-
merises into a glassy variety possessing a strong refractive index (B. 14, 2787 ;
A. 248, 203 ; B. 38, 691). Itaconic Mono-esters (B..30, 2649).
516 ORGANIC CHEMISTRY
CHa=C - CCK
Itaconic Anhydride, /O, m.p. 68°, b.p.30 146°. Its name is
CH2— OX
formed by interchanging the syllables of aconitic acid. Itaconic anhydride is
obtained from the hydrate (B. 13, 1539), and from the silver salt by means of
acetyl chloride (B. 13, 1844). It has been found in the distillate obtained
when citric acid is heated (B. 13, 1542), and is probably produced by the de-
composition of the aconitic acid which is first formed. It crystallizes from
chloroform. When distilled at ordinary pressures it passes into citraconic
anhydride, which unites with water far less readily than itaconic anhydride.
Itaconanilic Acid, m.p. 151-5 (A. 254, 140).
Citraconic Acid, Methyl Maleic Acid, m.p. 91°, is formed when its anhydride
takes up water. The acid itself is soluble in water. Its volatility in steam is
due to its decomposition below 100° into water and the anhydride which vola-
tilises. It resembles mesaconic acid in its behaviour towards KMnC>4 (below).
CH3CCOX
Citraconic Anhydride, \\ >O m.p. 7°, b.p. 213°, is found among the
HCCCK
distillation products of citric acid, probably through the transformation of the
first-formed itaconic anhydride, it is formed when citraconic acid or mesaconic
acid is heated alone ; and when treated with acetyl chloride. Prolonged heating
at about 200° changes it partly into Xeronic Acid or diethyl maleic anhydride
(p. 519). Bromccitraconic Anhydride, m.p. 99° (B. 27, 1855).
Hydrogen converts citraconic and mesaconic acids (below) into pyrotartaric
acid. Addition products with halogens and halogen acids have been examined
already as substitution products of pyrotartaric acid (pp. 500, 501). Either acid.
when electrolyzed, yields allylene,
Citraconanilic Acid, m.p. 153°
CH3C^CH (p. 90).
p. 153° (A. 254-, 135).
Citraconanil, m.p. 98° (B. 23, 2979 ; 24, 314).
Mesaconic Acid, Methyl Fumaric Acid, Hydroxyietrinic Acid, C8H4(CO2H)2,
m.p. 202°, is formed when citraconic or itaconic acid is heated with a small
quantity of water at 200° ; by the action of sunlight on an ether-chloroform
solution of citraconic acid, containing a trace of bromine ; by heating citraconic
acid with dilute nitric acid, concentrated halogen acids, or concentrated sodium
hydroxide solution (A. 269, 182 ; B. 27, R. 412) (comp. a- and ^-Methyl Malic
Acid, pp. 556, 557) ; and from dibromomethyl acetoacetic acid (p. 420). It is
soluble with difficulty in water, and is non-volatile in steam. KMnO4 oxidizes
it to pyroracemic and oxalic acids (A. 305, 407) ; barium salt, CBH4O4Ba+4H2O ;
dimethyl ester, b.p. 203° ; diethyl ester, b.p. 229°.
The relation between the results of partial hydrolysis and of esterification of
the mesaconic acids have been investigated in detail. Hydrolysis of the di-alkyl
ester yields a-Mesaconic Monomethyl Ester, m.p. 84°, and mono-ethyl ester, m.p. 68°,
HOCO-CH : C(CH8)COOR ; whilst partial esterification yields a mixture of
a-mesaconic acid esters and ^-Mesaconic Monomethyl Ester, m.p. 52°, and mono'
ethyl ester, m.p. 67°, HOCO.C(CH3) : CHCOOR. The structure of the latter
bodies is demonstrated by their being prepared in a state of purity when y-dibromo-
a-methyl acetoacetic ester (p. 420) is boiled with water and barium carbonate.
The a- acid esters are weaker acids than the /J-compounds in which the free
carboxyl group is united to a quarternary carbon atom ; in the dialkyl esters
this group is more difficult to hydrolyze. The acid-esters give rise to a corre-
sponding series of mono-ester acid chlorides, amides, anilides, etc.
Mesaconyl Chloride, C1OC.C(CHS) : CHCOC1, b.p.14 65°, reacts with two mole-
cules of aniline and forms a-mesaconanilide acid chloride, C1OC.C(CH3) : CHCONH-
C6H8 (A. 353, 139).
Bromomesaconic Acid, m.p. 220° (B. 27, 1851, 2130).
The Homologues of Itaconic, Citraeonie, Mesaconic and Aticonic Acids have
become known mainly by the painstaking investigations of R. Fittig and his co-
uorkers (A. 304, 117; 305, i); they will be described before the glutaconic
acids which are homologous with the above-named acids.
The parent substances from which these acids are formed are the alkyl
paraconic acids (p. 557), which are prepared by condensation of aldehydes with
succinic acid or pyrotartaric acid by means of acetic anhydride. On distillation
they yield unsaturated monobasic acids, and anhydrides of two acids of the
HOMOLOGOUS, ITACONIC, ETC., ACIDS 517
taconic and citraconic series isomeric with the particular paraconic acid employed,
f the alkyl paraconic esters are warmed with sodium alcoholate in alcoholic
olution they are converted into the sodium salts of the corresponding itaconic
mono-esters, from which the acids themselves are obtained by hydrolysis (A. 255,
6 ; 256, 50). Thus, terebic acid and sodium ethoxide produce teraconic acid ;
md similarly y-dimethyl paraconic acid yields y-dimethyl itaconic acid:
C02C2H6 C02C2H5
H— CH2-f-NaOCaH5 = ™3>C=C— CHa+C2H,OH
CO C02Na
Alkyl itaconic acids when heated alone are converted into the anhydrides of
alkyl citraconic acids. Alkyl citraconic acids become changed into alkyl itaconic
icids when heated with water at 130-150°. This depends on the decomposition
f the alkyl citraconic acids into anhydride and water below its boiling point,
and the gradual transformation of this anhydride at a somewhat higher tempera-
ure into itaconic anhydride, which takes up water to form the stable acid.
The alkyl citraconic acids are easily converted into the corresponding alkyl
mesaconic acids by the action of sunlight on an ether-chloroform solution of the
acids to which a little bromine had been added.
When the alkyl itaconic acids are boiled with sodium hydroxide solution, the
position of the double bond becomes changed, and there are produced alkyl
mesaconic acids and a new series of isomeric acids named by Fittig, alkyl aticovic
icids. The reaction is, however, not a general one, since y-methyl itaconic acid
s stable towards boiling sodium hydroxide solution, whilst y-dimethyl itaconic
icid readily yields the aticonic acid (A. 330, 292). The alkyl aticonic acids when
boiled with sodium hydroxide solution pass mainly into the alkyl itaconic acids,
50 that ultimately a point of equilibrium is reached which is not changed by
urther boiling.
A mixture of alkyl itaconic and alkyl aticonic acids (or alkylidene pyrotartaric
icids) also result from the condensation of ketones, such as acetone and alkyl
nethyl ketone, with succinic acid ester by means of sodium methoxide (Stobbe,
3.30,94; A. 321, 83).
Aromatic itaconic and aticonic acids can be prepared by the two nucleus-
ynthetic methods (Vol. II.).
The alkyl itaconic and alkyl mesaconic acids are as little volatile in steam as
he itaconic and mesaconic acids themselves, whilst of the alkyl citraconic acids,
ome are only obtained as anhydrides, and others are dissociated into the
j .nhydride and water below 100°, like citraconic acid ; these anhydrides are
. -olatile in steam. The calcium and barium salts of the alkyl mesaconic acids
, re readily soluble in water, whilst the corresponding alkyl itaconic acid salts
" j issolve with difficulty.
The itaconic acids are converted into the paraconic acids, from which they
.^ '•ere prepared, by heating with hydrochloric or hydrobromic acids and by suitable
^ reatment with sulphuric acid. The isopropyl itaconic acid alone behaves
^ xceptionally, by yielding isopropyl isoparaconic acid, isomeric with the original
;.;;. opropyl paraconic acid :
CH H*°<
^vf"*T-T /-» /^TT /"^TT V V-' XJ. «^. /^TT /"*TT f* f*f\ ^ V/J-Ao'Xv f^TT /^TT /** f*f°\ TT
sS\sn. — ^ — v^xl — Lx±l2 ~sr*-I-Ts?\*>rl.\sri=z\^——\_,{j'L —?- ___t>_x>UJtl.v_-rl =v^ — ^w2rl
>propyl Paraconic Acid.
iole- ^n3 \o
O CO CH2.OX
sopropyl Itaconic Anhydride.
[2C— CO- ^ CH3
CH2CO2H
Isopropyl Itaconic Acid.
^"3 \Q ^-"a I
CH.OX O CO
Isopropyl Citraconic Anhydride. Isopropyl Isoparaconic Acid.
Reduction with sodium amalgam converts the alkyl itaconic, alkyl citraconic,
, id alkyl mesaconic acids into the corresponding succinic acids, the first acid
: acting least readily than the third, and the second most easily of all three.
5i8 ORGANIC CHEMISTRY^
Homologous Itaconic Acids.
CH3.CH=C.C01H
y-M ethyl Itaconic Acid, Elhylidene Succinic Acid, m.p.
CH2CO2H
165°. y-Ethyl Itaconic Acid, m.p. 162°. y-n-Propyl Itaconic Acid, m.p. 159°.
y-Isopropy I Itaconic Acid, m.p. 189°. y-Isobutyl Itaconic Acid, m.p. 160°. y-n.-
Hexyl Itaconic Acid, m.p. 129°. Teraconic Acid, y- Dimethyl Itaconic Acid,
(CH3)2C=C.C02H,
m.p. 162°, is prepared from terebic acid (p. 517, and
CH2CO2H
Vol. II.) ; and by the condensation of succinic ester and acetone by means of
sodium ethoxide(B. 36, 197; J. pr. Ch. [2] 67, 197). Hydrobromic or sulphuric
acid reconverts it into terebic acid ; water at 190° decomposes it into CO2 and
isocaprolactone (C. 1889, I. 780); anhydride, b.p. 275°. y-M ethyl Ethyl Itaconic
acid. m.p. 181° with decomposition.
CH2=C.COaH
a-M ethyl Itaconic Acid, m,p. 150°, is obtained from pyro-
CH3— CH.C02H
cinchonic acid (below) ; anhydride, m.p. 63°, is produced by heating anhydro-
methyl aconitic acid (C. 1906, II. 21).
CH2=C— COOH,
aa -Dimethyl Itaconic Acid, m.p. 141°, is prepared from
(CH3)2CCOOH
a-bromotrimethyl succinic acid and diethyl aniline ; anhydride, b.p. 210-215°;
diethyl ester, b.p. 20 127° (C. 1902, 1. 180 ; 1904, 1. 434).
ay-Dimethyl Itaconic Acid, CH3CH : C(COOH).CH(CH3)COOH, m.p. 202°
(anhydride, b.p.26 131°) and a.-Ethyl Itaconic Acid, CH2: C(COOH).CH(C2H6)COOH
(anhydride, m.p. 52), result from boiling methyl ethyl maleic acid (p. 519) with
sodium hydroxide solution ; the former also, from ay-dimethyl paraconic acid
by boiling it with NaOC2H5 solution (B. 39, 1535). The alkyl itaconic acids
mostly have no sharp melting points, owing to their tendency to form anhydrides.
Homologous Citraconic Acids, Alkyl Maleic Acids.
CH3— CHt—C— C02H
y-Methyl Citraconic Acid, Ethyl Maleic Acid, \\ , m.p. 100°,
CH.CO2H
can also be obtained by heating jS-ethyl malic acid (B. 37, 2382 ; 38, 2737) ;
anhydride, b.p. 229°, is obtained from ethyl fumaric acid, p. 519) by heating it
with acetyl chloride. When vapourised with ammonium it forms the imide,
m.p. 141°. y-Ethy I Citraconic Acid, n-Propy I Maleic Acid, m.p. 94°; anhydride,
b.p. 224°. y-Propyl Citraconic Acid, m.p. 80°. y-Isopropyl Citraconic Acid,
m.p. 78°. y-fsobutyl Citraconic Acid, m.p. 75°. y-Hexyl Citraconic Acid, m.p. 86°.
(CH3)2CH.C— C(\
y-Dimethyl Citraconic Anhydride, >O, m.p. 5°, b.p.n 138°
CH.OX
(C. 1899, 1. 668, 780).
The y-alkyl citraconic acids or monoalkyl maleic acids do not melt sharply
on account of the formation of anhydrides. The a-alkyl citraconic or dialkyl
maleic acids only exist as anhydrides, which are formed when the acid is liberated
from its salts by stronger acids.
Pyrocinehonic Anhydride, Dimethyl Maleic Anhydride, a-Methyl Citraconic
CH3.CCO
Anhydride, \\ >O, m.p. 96°, b.p. 223°, is formed when cinchonic acid
CHS.CCO/
(q.v.) is heated :
CO2H CO.O.CO
I -H20 | |
CHa.CH.CH.CO,H • > CH3C C
I I ~c°2 !
CO— O— CHa CH,
Cinchonic Acid. Pyrocinchonic Anhydride.
It also results, together with terebic acid, when turpentine oil is oxidized with
nitric acid; from a-dichloro- and a-dibromo-propionic acid and silver (B. 18, 826,
835) '• by condensation of pyroracemic acid and sodium succinate by means of
acetic anhvdi
ATICONIC ACIDS 519
; anhydride (A. 304, 158) ; by distillation of ajS-dimethyl malic acid (p. 556)
under reduced pressure (a method of preparation) ; by distillation of anhydro-
methyl aconitic acid (C. 1906, II. 21).
Dimethyl ester, b.p. 219°, and diethyl ester, b.p. 237°, are prepared from silver
pyrocinchonate and iodo-alkyls (B. 33, 1410). The solution of pyrocinchonic
anhydride reacts strongly acid and decomposes alkali salts forming pyrocincho-
nates, the constitution of which has already (p. 513) been discussed. Ferric
chloride produces a dark red coloration in pyrocinchonic anhydride solutions.
Reduction produces two dimethyl succinic acids (p. 494). It unites with chlorine
to form dimethyl dichlorosuccinic anhydride (B. 26, R. 190). When boiled with
20 per cent, sodium hydroxide solution, pyrocinchonic acid is converted into
dimethyl fumaric acid and /2-methyl itaconic acid (A. 304, 156). Pyrocinchonic
ester, when heated with alcoholic ammonia, yields amino-dimethyl-succinimide
(p. 557) and pyrocinchonimide, m.p. 119° (B. 33, 1408), which, on hydrolysis yields,
in part, ^S-methyl itaconic acid.
Methyl Ethyl Malelc Anhydride, b.p. 236°, is formed by condensation of pyro-
tartaric acid and pyroracemic acid, by means of acetic anhydride (A. 267, 214) ;
by distillation of ay-dimethyl paraconic acid whereby a-methyl £y-pentinic acid
is also formed (B. 39, 1535) ; by the slow distillation of methyl ethyl malic acid ;
imide, m.p. 67° ; dimethyl ester, b.p. 235°. The imide and anhydride can also be
obtained from the destruction of haematin or hasmatinic acid (comp. haemoglobin)
(A. 345,i).
Methyl Propyl Malelc Anhydride, b.p. 242° (imide, m.p. 57°) and Methyl
IsopropylMaleic Anhydride, b.p. 241° (imide, m.p. 45°) are obtained from methyl
propyl and methyl isopropyl malic acid (A. 346, i).
Xeronic Anhydride, Diethyl Maleic Anhydride, b.p. 242°, is prepared by
heating citraconic anhydride (A. 346, i).
Homologous Mesaconic Acids, Alkyl Fumaric Acids. For the formation of
alkyl mesaconic acids from the corresponding alkyl itaconic and alkyl citraconic
acids, seep. 517.
The products of reaction of alcoholic potassium hydroxide and the y-dibromo-
derivatives of monoalkyl acetoacetic ester belong to the alkyl fumaric acid series
(C. 1899, I. 780) ; hydroxytetrinic acid being mesaconic acid, and hydroxy-
penlinic acid being ethyl fumaric acid, etc. (p. 420).
The reaction is most simply explained by the assumption that keto- or hydroxy-
aldehydic acids are first formed, which are then converted into unsaturated car-
boxylic acids (B. 32, 1005) :
X,CH.COCHR'.COaR > OCH.CO.CHR'.CO2R
O.CH.C(OH)=CR'.COtR > COaH.CH : CR'.CO2R.
Also, monoalkyl fumaric acids are obtained from monoalkyl ethane tri-
carboxylic acids by the introduction of halogen and subsequent splitting off of
halogen acid and CO8 (B. 24, 2008).
Ethyl Fumaric A cid, -/-Methyl Mesaconic A cid, m.p. 194°- ^..-Propyl Fumaric
Acid, y -Ethyl Mesaconic Acid, m.p. 174°. Isopropyl Fumaric Acid, y-Dimethyl
Mesaconic Acid, m.p. 184°. n.-Butyl Fumaric Acid, y-Propyl Mesaconic Acid,
m.p. 170°. y -Isopropyl Mesaconic Acid, m.p. 185°. y-Isobutyl Mesaconic Acid,
m.p. 205°. y-Hexy I Mesaconic Acid, m.p. 153°.
Dimethyl Fumaric Acid, a-M ethyl Mesaconic Acid, m.p. 239° ; diethyl ester,
b.p. 235°, is formed when diazopropionic ester is heated (p. 410) (B. 37,
1272).
Aticonie Acids. — For the formation of these acids from the alkyl itaconic
acids by synthetic methods, see p. 517. Dimethyl Aticonie Acid, l-M ethyl Vinyl
Succinic Acid, y-Methyl Methylene Pyrotartaric Acid, cjj^^'^^CO^H '
m.p. 146°, results when teraconic acid is boiled with sodium hydroxide solu-
tion. Isobutyl Aticonie Acid, ^-Isopropyl Vinyl Succinic Acid, CH*>CH.CH —
CH.CH<£Q «.gO»Hf m.p. 93°. Hexyl Aticonie Acid, 2-Amyl Vinyl Succinic Acid.
520 ORGANIC CHEMISTRY
CH3[CH2]4CH=CH.CH<£g22£°2H, m.p. 78° (A. 304, 117; 305, i). Methyl
Ethyl Aticonic Acid, y-Ethylidene y-M ethyl Pyrotartaric Acid, i ,i-Dimethyl Vinyl
Succinic Acid, (CH3)CH:C(CH3)CH<£o^°2H, m.p. 142°, is the chief product
of reaction between methyl ethyl ketone and sodium ethoxide on succinic ester.
Oxidation converts it into acetic acid and laevulinic acid (A. 321, 106).
In indifferent solvents, the alkyl aticonic acids readily take up bromine. The
dibromides, on losing HBr, change into the bromolactonic acids, which are con-
verted by hydrogen into isoparaconic acids, and by boiling water, or when standing
in alcoholic solution, into the neutral dilactones :
HOCO
CH2:C(CH
,).CH
HOCO.CHj
Dimethyl Aticonic Acid.
HOCO
CH,Br.CBr(CH
HOCO
•).CH
.CH^
O CO
CH2.C(CH3).CH
O— CO.CH,
Isoheptodilactone.
The formation of dilactones requires that each of the two doubly bound "carbon
atoms shall stand in the y-position to one of the two carbonyl groups (A. 304, 135).
This shows the alkyl aticonic acids to be y8-unsaturated acids. It follows, there-
fore, that one of the itaconic acids is theoretically not possible, since this acid
lacks the 8 carbon atom. The aticonic acids can be looked on as being vinyl
succinic acids, or can be derived from pyrotartaric acid, cantiderations which are
indicated in the names given to the dimethyl aticonic acids.
The dilactones, obtained from the aticonic acids through the bromolactonic
acids, are converted by prolonged boiling in water into isomeric unsaturated
lactonic acids, known as isaconic acids. Sodium amalgam converts them into
isoparaconic acids, in the same way that the better known aconic acids give
paraconic acids.
Glutaeonie Acid, CO2H.CH : CH.CH2.CO2H, m.p. 132°, is prepared from
dicarboxylic glutaconic ester by hydrolysis with hydrochloric acid (A. 222, 249);
fromcoumalic ester and barium hydroxide (A. 264, 301) ; from/?-hydroxyglutaric
acid (p. 559), and sodium hydroxide solution (B. 33, 1452). It is isomeric with
itaconic, citraconic, mesaconic and ethylidene malonic acids.
The zinc salt is deposited from its boiling solution ; ethyl ester, b.p. 237°, is
most readily obtained by distillation of /?-acetoxyglutaric ester (p. 599). Under
certain conditions it polymerises to a di-molecular substance which, on hydrolysis,
yields diglutaconic acid [C3H4(CO2H)2]2, m.p. 207°. This acid is also formed by
hydrolysing the dimolecular isaconitic ester (q.v.), whilst the di-molecular
glutaconic dicarboxylic ester (9.1;.) yields a diglutaconic acid, m.p. 234° (B. 34,
675)- When warmed with sodium ethoxide two molecules of glutaconic ester
unite with the loss of alcohol, and there is formed dicarboxycyclohexenone acetic
ester (B. 37, 2113, comp. C. 1903, I. 960).
Glutaconic Anhydride, m.p. 82°, is formed when glutaconic and jS-hydroxy-
glutaconic acids are heated (Kekulf) ; and from glutaconic acid and acetyl chloride
(m.p. 87°, B. 27, 882) ; the imide, aa-Dioxypyridine, CH<':>NH or
m.p. 183°, is formed (i) from glutaconaminic acid; (2)
from glutaconamide, and (3) from jS-hydroxyglutaric amide, when these are
heated with H2SO4 to 130-140°. Na and CH3I react with it to produce glutaconic
methylimide ; with nitrous acid it gives rise to a nitroso-compound ; when
distilled over zinc dust pyridine is formed : PCI, produces pentachloropyridine,
C6C16N (see Constitution of Pyridine, Vol. II.).
fi-Chloroglutaconic Acid, m.p. 129°, is prepared from acetone dicarboxylic
acid and PC18 (p. 566 ; comp. glutinic acid, p. 523). Tetrachloroglutaconic Acid,
m.p. 109-110° (B. 26, 2697).
Homologous Glutaeonie Acids. The alkylated glutaconic acids are best
obtained by heating the acetyl compounds ct the alkylated /S-hydroxyglutaric
acids, just as glutaconic acid itself from alkylated glutaconic acids (comp. C. 1903,
The CHt- group of the glutaconic ester is replaceable by alkyl groups by means
HOMOLOGOUS GLUTACONIC ACIDS 521
of sodium or sodium alcoholate and iodoalkyls. It appears, therefore that the
second carboxyl group exerts its influence on the methylene group across the
"thylene group ;
• -LAJ ^ and CH2MX)R
Glutaconic Ester. Malonic Ester.
The reaction with C2H6ONa and CH3I not only converts glutaconic ester into
aa-di methyl glutaconic ester, but also produces ay-dimethyl glutaconic ester.
Of this latter compound two desmotropic forms, I. and II. (see below) exist;
further methylating of II. results in the production of aay-trimethyl glutaconic
ester (C. 1903, 1. 1405) :
I. RO2C.CH(CH3)— CH=CHCO2R and II. RO2C.C(CH8)=CH— CH2CO2R
.OaC.C(CH8)a— CH=CHCO2R RO2C.C(CH8)=CH— CH(CH8)COaR
R02C.C(CH,)=CH— C(CH3)2C02R
The existence of the two desmotropic modifications HO2C.CR =CH — CH2CO2H
and HO2C.CHR — CH=CHCO2H is also demonstrated by the identity of the
ajS- and j3y-dialkyl glutaconic acids, obtained by the following syntheses : sodium
cyanacetic ester and acetoacetic ester produce sodium cyano-jS-methyl-glutaconic
ester (i); CH3I converts this into a-cyano-a/?-dimethyl glutaconic ester (2),
which by hydrolysis and loss of CO2 is change'd into aj8-dimethyl-glutaconic
acid (3). This substance is identical with the decomposition product of the con-
densation of cyanacetic ester and a-methyl acetoacetic ester (4), which should
be similar to j8y-dimethyl glutaconic acid (5) (C. 1906, I. 183) :
/~»TT r>"tj /^TI
v^in 8 v_xii 3 v^XJL •
(i) RO2C.CH=C— CNa(CN)C02R > (2) RO2C.CH=C C(CN)CO8R
CH3 CH3 CH8 CH8
(3) HO2C.CH=C CHCO2H « (5) HO2C.C=C— CH2CO2H
:CH3 CH3 CH3 CHa CH3 CN
R02C.CH— CO-j-CHNaC02R > (4) ROaC.C=C CNaCO2R
KThe alkyl glutaconic acids show cis-trans isomerism.
1-M ethyl Glutaconic Acid, Homomesaconic acid, HO2C.CH : C(CH8).CHaCO2H.
form 147°, trans-form, 116°, is prepared from cyano-j8-methyl-glutacqnic
ester (see below); from carboxyl /? -methyl glutaconic ester CO2R)2CH.C(CH8) :-
CHCO2R ; and from isodehydracetic acid (lactone of aci-acety I ^-glutaconic mono-
ester, CH3C(OH) : (CO2R).C(CH3) : CHCO2H) obtained by splitting the as- and
trans-forms. The cts-acid can be transformed into the trans-a,cid by boiling with
strong alkali. The cis-acid forms an anhydride, m.p. 86°; imide, m.p. 194°
(A. 345, 60).
aj8- or fay-Dimethyl Glutaconic Acid (see above), m.p. 148°, is formed by the
method (3), above ; also from j8-methyl glutaconic ester by the action of sodium
and iodomethane (A. 345, 117) ; anhydride, b.p.2, 162° ; imide, m.p. 189°.
aa-Dimethyl Glutaconic Acid, HO2C.C(CH3)2CH : CHCO2H, ct's-form, m.p.
134° ; trans-form, m.p. 172°, is prepared from a-dimethyl glutolactonic acid
(B. 33, 1920) ; from j3-hydroxy a-dimethyl glutaric acid ; from glutaconic ester,
sodium and iodomethane ; some ay-Dimethyl Glutaconic Acid, m.p. 147°, is also
tned (above) (C. 1903, II. 1315).
aay-Trimethyl Glutaconic Acid, cis-iorm, m.p. 125°, trans-iorm, m.p. 150°,
Qrmed from jS-hydroxy trimethyl glutaric acid and by methylating ay-dimethyl
itaric acid. The cis- acid gives rise to an anhydride, m.p. 88 .
aap-Tritnethyl Glutaconic Acid, cis-iorm, m.p. 133°, trans-iorm, m.p. 148*
522 ORGANIC CHEMISTRY
(C. 1903, II. 1315). aBy-Trimethyl Glutaconic Acid, m.p. 127° ; anhydride, m.p.
119° ; imide, m.p. i8o6 (C. 1906, I. 185).
Hydroinueonic Acids.
aj8-acid : CO2H.CH2CHaCH=CHCO2H, m.p. 169°, stable form.
0y-acid : CO2H.CH2CH=CH.CH2CO2H, m.p. 195°, labile form.
The labile acid is formed by the reduction of dichloromuconic acid or muconic
acid (below), and of diacetylene carboxylic acid (p. 523). It dissolves with
difficulty in cold water, and is oxidised to malonic acid by potassium per-
manganate. When boiled with sodium hydroxide solution it is transformed into
the stable acid, which is oxidised to succinic acid by permanganate. Sodium
amalgam converts the labile acid into the stable form and reduces this to adipic
acid (p. 505). Dichlorides and Dimethylene ester (C. 1901, II. 1119).
a-Mcthylene Glutaric Acid, CH2 : C(COOH)CH2.CHaCOa.H, m.p. 129-130°,
and a-Ethylidenep-Methyl Glutaric Acid, CHS.CH : C(CO2H)CH(CH3)CHaCOaH,
m.p. 129°. The esters of these acids are obtained by the polymerisation of acrylic
and crotonic acids respectively (pp. 294, 295) by means of sodium alcoholate
(B. 33, 3766 ; 34, 427). a-Methylene glutaric acid is also formed by the dis-
tillation of a-methyl a-hydroxyvaleric acid (B. 36, 1202). Suitable methods of
reduction convert these acids into a-methyl glutaric acid and a-ethyl /3-methyl
glutaric acids respectively.
a-Ethylidene Glutaric Acid, CH3CH : C(COOH)CHaCH2CO2H, m.p. 152°, see
8-Caprolactone Carboxylic Acid (p. 560). Sodium hydroxide solution converts
it into a-Vinyl Glutaric acid, CH2:CH.CH(CO2H)CHaCHaCO2H, m.p. 97° (B. 31,
2000).
Isoamylidene Glutaric Acid, (CH3)2CHCH2CH : C(CO2H)CH2CH2CO2H, m.p.
15°, is formed together with diisovalerylidene glutaric acid (see below).
Allyl Succinic Acid, CH2:CH.CHaCH(CO2H)CH2CO2H, m.p. 94°, is prepared
from allyl ethylene tricarboxylic ester (B. 16, 333). Allyl Methyl- and Allyl'
Ethyl Succinic Acid, see B. 25, 488.
C. Dioleflne Dicarboxylic Acids.
Diallyl Malonic Acid, (CH2=CHCH2)2C(CO2H)2, m.p. 133°, with hydrobromic
CH2.CH2.CH2.C.CH2.CH.aCH2
acid yields a dilactone, | A I . It breaks down into
O CO CO O
CO2 and diallyl acetic acid when heated (p. 306).
Muconic Acid, CO2H.CH=CH-CH=CH.CO2H, m.p. 292°, with decomposi-
tion, is formed when alcoholic potassium hydroxide acts on the dibromide of
/?y-hydromuconic acid ; also, synthetically, from glyoxal and two molecules of
malonic acid by means of pyridine ; dimethyl ester, m.p. 158° (B. 35, 1147). Di-
chloromuconic Acid, C6H4C12O4, results when PC15 acts on mucic acid (B. 24,
R. 629). It yields jSy-hydromuconic acid with sodium amalgam (B. 23, R. 232).
Dichloromuconic Acid Dichloride, and Dimethyl Ester (C. 1901, II. 1119).
Isomeric muconic acids are not known.
CHa:C.COOH
Dimethylene Succinic Acid, may be considered as being the
CH2:C.COOH
parent substance of a large number of strongly coloured well-crystallising acids
ot the aromatic series (Vol. II.). It easily passes into a more deeply coloured
anhydride, and exhibits a reversible difference of state in violet and ultra-violet
« i ^P' 3^' Therefore Stobbe named the hypothetical acid Fulgenic Acid
(iulgere=to shine) and the anhydride fulgide. The lesser known aliphatic
fulgemc acids and fulgides are colourless (A. 359, i, etc.).
Succinic Acid, aaSS-Tetramethyl Fulgtnic Acid, (CHS)2C:-
: C(CH8)a, m.p. 230° with decomposition, and Isopropylidene
™TT Succinic Acid, oaS-Dimethyl Isopropyl Fulgenic Acid, (CH8)2C:-
C(COOH)C(COOH):CHCH(CH8)2, m.p. 226° with decomposition, result from
ne reaction of teraconic ester and acetone or isobutyl aldehyde respectively,
with sodium ethoxide. The anhydrides, m.ps. 59° and 72°, are formed by means
of acetyl chloride (B. 38, 3673, 3683).
is obtltn^T*' Gk\talicAcid.' CH2[C(C02H):CHCH2CH(CH3)a],, m.p. 220°, and
I from glutaric acid and isovaleraldehyde with acetic anhydride and
sodium ethoxide or sodium (A. 282, 357).
TRIHYDRIC ALCOHOLS 523
D. Acetylene and Polyacetylene Dicarboxylic Acids.
Acetylene Diearboxylic Acid, CO2H.C=C.CO2H+2H2O, m.p. 175° with
decomposition, is obtained when aqueous or alcoholic potassium hydroxide acts
on dibromo- and isodibromo-succinic acid (A. 272, 127). It effloresces on
exposure. The anhydrous acid crystallises from ether in thick plates. The acid
unites with the halogen acids to form halogen f umaric acids, whilst with bromine
and iodine it yields dihalogen fumaric acids (p. 515). Its esters unite with bromine
and form dibromomaleic esters and dibromof umaric esters (B. 25, R. 855). With
water they yield oxalacetic ester (B. 22, 2929). They combine with phenyl-
hydrazine and hydrazine, forming the same pyrazolone derivatives as oxalacetic
ester (B. 26, 1719); and with diazobenzene imide they form phenyltriazole
dicarboxylic ester (B. 26, R. 585). Oxalacetic ester and acetylene dicarboxylic
ester are condensed by alcoholic potassium hydroxide to aconitic ester (B. 24, 127).
(See also Acetoxymale'ic Anhydride, p. 565.) The primary potassium salt, C4O4HK,
is not very soluble in water, and when heated decomposes into CO2 and potassium
propiolate (p. 303) ; silver salt breaks down readily into CO2 and silver acetylide
(A. 272, 139); diethyl ester, b.p.15 145-148°, is obtained from dibromosuccinic
ester with sodium ethoxide (B. 26, R. 706). (See also Thiophene Tetracarboxylic
Esters.)
Glutinie Acid, CO2H.C=C.CH2.CO2H, m.p. 145° with evolution of carbon
dioxide, is obtained by the action of alcoholic potassium hydroxide (B. 20, 147)
upon chloroglutaconic acid (p. 520).
Diaeetylene Dicarboxylic Acid, CO2H.C^C— C=C.CO2H+H2O, is made by
the action of potassium ferricyanide on the copper compound of propiolic
acid (B. 18, 678, 2269). It assumes a dark red colour on exposure to light, and at
177° explodes with a loud report. Sodium amalgam reduces it to hydromuconic
acid, and at the same time splits it up into adipic and propionic acids. The
ethyl ester t b.p.20o 184°. Zinc and hydrochloric acid decompose it and yield
propargylic ester (p. 303).
Tetra-acetylene Dicarboxylic Acid, CO 2H.C=C.C=C.C^C.C^C.CO2H. Carbon
dioxide escapes on digesting the acid sodium salt of diacetylene dicarboxylic acid
with water, and there is formed the sodium salt of diacetylene monocarboxylic
acid, CH==C.CHCO2Na, which cannot be obtained in a free condition. When
potassium ferricyanide acts on the copper compound of this acid, tetra-acetylene
dicarboxylic acid is formed. This crystallizes from ether in beautiful needles,
rapidly darkening on exposure to light and exploding violently when heated.
Consult B. 18, 2277, for an experiment made to explain the explosibility of this
derivative.
V. TRIHYDRIC ALCOHOLS: GLYCEROLS AND THEIR
OXIDATION PRODUCTS
The trihydric alcohols, or glycerols, and their oxidation products
are connected with the dihydric alcohols (glycols) and their oxidation
products.
The glycerols, so-called after their most important member, are
obtained from the hydrocarbons by the substitution of three hydroxyl
groups for three hydrogen atoms, linked to different carbon atoms.
As the number of hydroxyl groups increases, the number of theoreti-
cally possible classes of glycerols, in contrast to the glycols, also becomes
greater. The number of possible classes of oxidation products also
grows accordingly, and in the case of the trihydric alcohols this number
is 19. However, this chapter of organic chemistry has been less regu-
larly developed than that pertaining to the dihydric derivatives, and
it may be said that the glycerols serve, even to a less degree than the
glycols, as parent bodies for the preparation of the various classes
524 ORGANIC CHEMISTRY
belonging here, some of which are : dihydroxymonocarboxylic acids,
monohydroxydicarboxylic acids, diketone-monocarboxylic acids, tricar-
boxylic acids.
Hydroxydialdehydes, hydroxydiketones, trialdehydes, aldehyde-diketones
and triketoncs are represented to only a slight extent, if at all. The same may
be said of the hydroxyaldehyde ketones, hydroxyaldehydic acids, hydroxyketonic
acids, aldehyde-carboxylic acids, and aldehyde-ketone-carboxylic acids.
I. TRIHYDRIC ALCOHOLS
Glycerol stands at the head of this class, although it is not a tri-
primary alcohol, but rather a diprimary-secondary alcohol. The
simplest imaginable triprimary alcohol would have the formula CH-
(CH2OH)3, and could be referred to trimethyl methane, CH(CH3)3,
whereas glycerol is derived from propane, and considering the structure
of the carbon nucleus, it is the simplest trihydric alcohol.
Although it may appear unnecessary to develop all the possible kinds of
trihydric alcohols and their oxidation products, as was done with the glycols,
yet the oxidation products theoretically possible from glycerol will be deduced.
By enlarging this scheme we really construct a comparative review of the oxygen
compounds, obtainable from methane, ethane, and propane.
It is also possible to tabulate the formulae of the oxygen derivatives of a
hydrocarbon in such manner that the hydrogen atoms may be regarded as re-
placed, step by step, by hydroxyl groups, and we may indicate the number of
hydrogen atoms attached to one carbon atom, which have been replaced by
hydroxyl groups.*
Thus, in compounds containing more than one hydroxyl attached to the
same carbon atom, numbers are employed to express the formulae of ortho-
derivatives, usually only stable in the form of ethers. When a carbon atom of a
hydrocarbon is joined to hydrogen, and no hydrogen atoms are replaced by
hydroxyl, this is expressed by a zero :
M 'ethane = CH 4=o
I II III IV
0123 4
/H /OH /OH /OH /OH
C/H /H /OH /OH /OH
U\ C\H C\H C\OH C<OH
\H \H \H XOH
Ethane =CH3.CHa=oo
I
II
III
IV
V
VI
00
10
20
3°
22
32
33
II
21
31
CH,
CH2OH
CH(OH)2
C(OH,)
CH(OH)2
C(OH)3
C(OH)3
CH,
AH.
CH3
CH3
CH(OH),
CH(OH),
C(OH),
CH2.OH
CH(OH),
C(OH)3
CHa.OH
CH8OH
CH2OH
* The author is indebted to A . J. Baeyer in Munich for indicating this method
of exposition, " which has the great advantage of facilitating the derivation of
the possible hydroxyl compounds from the higher hydrocarbons, and also to
make apparent the degree of oxidation, i.e. the number of oxygen valencies which
have entered."
TRIHYDRIC ALCOHOLS
535
000
100
Pr
200
300;
3IO
CH3=0
320J
00
303i 322 323!
OIO
O20;
210
22Oi
302 i
321 313;
110
120:
301 |
311
312!
101
201
202 1
*2I2
222J
III
211
I2IJ
*22lj
The following formulae correspond with
I
II
IV
ooo
100
OIO
200
020
no
101
CH3.CHa.CH3
CHaOH.CH2.CH,
CHS.CHOH.CH8
CH(OH)a.CH2.CH,
CH8C(OH),CH3
CHaOHCH.OH.CH8
CHaOH.CHa.CH2OH
III: 300 C(OH)8.CHa.CH3
210 CH(OH)a.CH(OH)CH.
CH(OH)aCHa.CH2OH
CH2OH.C(OH)2CH3
CH2OH.CHOH.CH2OH
C(OH)3.CHOH.CH3
(COH)3.CH2.CH2OH
CH(OH)a.C(OH)2.CH3
CH(OH)2.CH2.CH(OH)2
CH(OH)2.CH.OH.CH2OH
CH2OH.C(OH)2.CH2OH
C(OH)3.C(OH)2.CH3
C(OH)3.CH2.CH(OH)8
C(OH)3.CHOH.CH2OH
CH(OH)2.C(OH)2.CH2.OH
CH(OH)2.CH(OH).CH(OH)2
C(OH)3.CH2.C(OH)3
C(OH)8.C(OH)a.CH2OH
C(OH)8.CHOH.CH(OH )a
CH(OH)1.G(OH)1.CH(OH)I
C(OH)3.C(OH)2.CH(OH)2
C(OH)8.CH(OH).C(OH),
C(OH)3.C(OH)2.C(OH)3
VI
VII
VIII
201
120
III
310
301
22O
2O2
211
121
320
302
311
221
212
303
321
3I2
222
322
313
323
these groups of numbers :
Propane
n-Propyl Alcohol
Isopropyl Alcohol
Propionic Aldehyde
Acetone
Propylene Glycol
Trimethylene Glycol
Propionic Acid
Unknown (pp. 336, 340)
/?-Hydroxypropionic Aldehyde
Hydroxyacetone, Ketol
Glycerol
Lactic Acid
Hydracrylic Acid
Pyroracemic Aldehyde
Malonic Dialdehyde (p. 347)
Glycerose
Di hydroxy acetone
Pyroracemic Acid
Formacetic Acid
Gly eerie Acid
Unknown
Unknown
Malonic Acid
Hydroxypyroracemic Acid (p. 543)
Tartronic Semialdehyde (p. 543)
Mesoxalic Dialdehyde
Unknown
Tartronic Acid
Mesoxalic Acid
Of the 29 possible hydroxyl substitution products of propane indicated in
the above tables by numbers, five are underlined, n-propyl alcohol, isopropyl
alcohol, propylene glycol, trimethylene glycol and glycerol. The remaining 24
can be looked on as being oxidation products of these. The dotted line connects
these products with the parent substance. Two are derivable from n-propyl
alcohol, one from isopropyl alcohol, five from propylene glycol and from trimethyl-
ene glycol ; eleven from glycerol. The following table shows them rearranged
according to their usual formulae — that is, their ortho-formulae minus water :
CHaOH
CH.OH
CH2OH
(in)
Glycerol.
CHO
CHOH
CH2OH
(211)
Glycenc
Aldehyde.
CO2H
CH2OH
CHO
C02H
COjH
CHOH
CO
<io
^0
CHOH
CH2OH
CH2.OH
CH2.OH
CH2.OH
CHO
(3")
(121)
(221)
(321)
1312;
Glyceric Acid.
Dihydroxy-
Unknown.
Hydroxypyro-
Tartronic
acetone.
racemic Acid.
Semialde-
hyde.
526 ORGANIC CHEMISTRY
CHO C02H CHO C02H CO2H
CHOH CHOH CO CO C(OH)a
CHO C02H CHO CHO CO2H
(212) (313) (222) (322) (323)
Unknown Tartronic Acid. Mesoxalic Di- Mesoxalic Semi- Mesoxalic
aldehyde. aldehyde. Acid.
Glyceric acid, tartronic acid, and mesoxalic acid are the only accurately known
representatives of these eleven oxidation products of glycerol. Glyceric aldehyde,
dihydroxyacetone, hydroxyacemic acid, tartronic semialdehyde, mesoxalic di-
and semi- aldehydes have all been investigated to only a small extent.
Three hydrogen atoms in glycerol can be replaced by alcohol or
acid radicals, producing ethers and esters :
(OH (OH (O.C2H80
C3H6<OH C8H6^O.C2H80 C,H5{ O.C2H3O
(O.C2H30 (O.C2H80 (O.C2H80
Acetin. Diacetin. Triacetin.
The haloid esters are the halohydrins :
C3H5(OH)2C1 C3H6(OH)Cla C3H6C1,
Monochlorhydrin. Dichlorhydrin. Trichlorhydrin.
Formation. — The trihydric alcohols are obtained (i) by heating the
bromides of the unsaturated alcohols with water ; or —
(2) By oxidizing the unsaturated alcohols with potassium per-
manganate (B. 28, R. 927).
(3) Aldehydes having the constitution RCH2CHO condense with
formaldehyde in the presence of lime to form triprimary glycerols :
RCH2CHO+3CHfO+H2O=RC(CH2OH)2CH2OH+HCOOH.
(4) Dialkyl ethers of glycerol are prepared by the magnesium
organic synthesis from carboxylic esters or alkoxyketones and chloro-
or iodo-substituted ethers.
Glycerol [Propanetriol], CH2OH.CHOH.CH2OH, m.p. 17° (solidifies
below o°), b.p.760 290° almost without decomposition, b.p.12 170°,
D15= 1*265, is produced (i) in small quantities in the alcoholic
fermentation of sugar ; hence is contained in wine (p. 114). (2) It
is prepared by hydrolysis of oils and fats, which are glycerol esters
of the fatty acids. Glycerol is also formed (3) from synthetic allyl
trichloride by heating it with water, and (4) from allyl alcohol when
it is oxidized with potassium permanganate. (5) Also, by the
reduction of dihydroxyacetone.
Historical. — Scheele discovered glycerol in 1779, when he saponified olive oil
with litharge, in making lead plaster. Chevreul, who recognized ester-like
derivatives of glycerol in the fats and fatty oils, introduced the name glycerol,
and in 1813 pointed to similarities between it and alcohol. The composition of
glycerol was established in 1836, by Pelouze. Berthelot and Lucca (1853), and
later Wurtz (1855), explained its constitution, and proved that it was the simplest
trihydric alcohol, the synthesis of which Friedel and Silva (1872) effected from
acetic acid :
C02H CH8 CH8 CH8 CH8 CH2C1 CH2OH
io -^ <W -<i AH -£ cWi -^ inci ^ UH
CH, CH8 CH, CHjCl CH,C1 CH8OH
GLYCEROL
527
(i) Acetone is obtained from calcium acetate. (2) Acetone by reduction
passes into isopropyl alcohol. (3) Propylene results when anhydrous zinc
chloride withdraws water from isopropyl alcohol. (4) Chlorine and propylene
yield propylene chloride. (5) Propylene chloride and iodine chloride unite to
form propenyl trichloride or allyl trichloride, the trichlorhydrin of glycerol.
(6) Glycerol is produced when trichlorhydrin is heated with much water to 160°
(B. 6, 969). Metallic iron and bromine convert propylene bromide into tri-
bromhydrm, which silver acetate changes to triacetin. Bases saponify the latter
and glycerol results (B. 24, 4246).
A second method of synthesizing glycerol is that of 0. Piloty (1897), which
starts from L. Henry's nitro-tert.-butyl glycerol, the condensation product of
formaldehyde and nitromethane. (i) NitroTtert.-butyl glycerol is reduced to
hydroxylamino-tert.-butyl glycerol, which is then (2) oxidized by HgO to di-
hydroxyacetone oxime :
:(CH2OH)2C:NOH+HC02H+H2O;
(3) bromine water converts this substance into dihydroxy-acetone :
2(CHaOH)aC : NCH+2Bra+H2O=2(CH2OH)2C : O+N2O+4HBrt ;
which, finally, is reduced to glycerol by sodium amalgam (B. 30, 3161) :
CH2OH
/CH2OH /CH.OH
(i) NOg.Cf-CH,OH > (2) NH(OH).CeCH;OH > (3) C=NOH >
NCH,OH \CH2OH
CHaOH
CHaOH CHaOH
CO > (4) CHOH
CH2OH CH2OH
Preparation. — Glycerol is produced in large quantities during the saponifica-
tion of fats and oils in soap and candle manufacture. When the process is carried
out with superheated steam, an aqueous solution of glycerol and free insoluble
fatty acids are formed. Pure glycerol is produced from its solution by distillation
under reduced pressure.
Properties. — Anhydrous glycerol is a thick, colourless syrup, which
slowly solidifies at o°, forming transparent crystals. With superheated
steam it distils entirely unaltered. It has a pure, sweet taste, hence
the name glycerol, and it is very hygroscopic, mixing in every pro-
portion with water and alcohol. It is fairly soluble (i : 3) in acetone
(A. 335, 319), but insoluble in ether. It dissolves the alkalis, alkali
earths and many metallic oxides, forming with them, in all probability,
metallic compounds similar to the alcoholates (p. 116). Copper Sodium
Glycerate, (CgHsC^CuNa^+sHgO, is obtained from glycerol, copper
oxide and sodium hydroxide solution (B. 31, 1453)-
Reactions. — (i) When glycerol is distilled with dehydrating sub-
stances, like sulphuric acid and phosphorus pentoxide, boric acid, or
preferably potassium hydrogen sulphate, it decomposes into water
and acrolein (p. 214).
(2) When heated to 430-450°, glycerol decomposes partly into
acrolein and partly into acetol :
— 2H.O — HaO
CH,:CH£HO ^ — 1 CHa(OH).CH(OH).CHa(OH) ^ CH,.CO.CHaOH
(comp. transformation of glycols into aldehydes and ketones, p. 312) ;
the acetol partially decomposes into acetaldehyde and formaldehyde
528 ORGANIC CHEMISTRY
which, like acrolem itself, unite with glycerol to form acetal-like
substances (A. 335, 209).
(3) When sodium glycerol or glycerol and sodium hydroxide are
heated together, hydrogen is evolved and mainly lactic acid is formed,
together with lower fatty acids, methyl alcohol and propylene glycol
(A. 335, 279).
(4) Platinum black and air, mercuric oxide and alkali or dilute
nitric acid convert glycerol into glyceric and tartronic acids ; sodium
and bismuth nitrate oxidize it to mesoxalic acid (B. 27, R. 666).
Energetic oxidation produces oxalic, glycollic and glyoxylic acids (p.
400) ; silver oxide gives rise to formic and glycollic acids (A. 335, 316).
(5) Moderated oxidation (with nitric acid or bromine) produces
glycerose, which consists chiefly of glyceraldehyde and dihydroxyacetone,
CO(CH2.OH)2. This unites with HNC and forms trihydroxy butyric
acid :
CH2OH COaH CO2H CO2H
CH.OH > CH.OH - — > CH.OH C(OH)2
CH2.OH CH2OH CH2.OH CH2OH CO2H CO2H
Glyceral- Dihydroxy- Glycerol. Glyceric Tartronic Mesoxalic
dehyde. acetone. Acid. Acid. Acid.
(6) Phosphorus iodide or hydriodic acid converts it into allyl iodide,
isopropyl iodide, and propylene (p. 104). (7) In the presence of
yeast at 20-30° it ferments, forming propionic acid. By Schizomycetes
fermentation, induced by Butyl bacillus (B. 30, 451 ; 41, 1412), normal
butyl alcohol (p. 118), trimethylene glycol and formic and lactic acids
result (p. 314).
(8) When glycerol is distilled with ammonium chloride, ammonium phos-
phates and other ammonium salts, /?-picoline (Vol. II.), as well as 2,5-dimethyl
pyrazine (Vol. II.), results. Under certain conditions it is only the latter which
is produced (24, 4105 ; B. 26, R. 585 ; 27, R. 436, 812 ; A. 335, 223).
Uses. — Glycerol is applied as such in medicine. It is also used in
gas meters. Duplicating plates and hectographs consist of mixtures
of gelatin and glycerol.
The bulk of glycerol is consumed in the manufacture of nitro-
glycerine (p. 529).
Glycerol Homologues.— i.z.s-Butyl Glycerol, CH3.CH(OH).CH(OH).CH2OH,
b.p.27 172-175°, is prepared from crotonylalcohol dibromide (p. 124).
[1,2,3-Pentanetriof], C2H6.CH(OH).CH(OH).CH2.OH, b.p.63 192°; [2,3,4-
Pentanctriol\, CH3.CH(OH).CH(OH).CH(OH).CH3, b.p.27 180°; & -Ethyl Glycerol,
CH3.CH2C(OH)(CH2OH)2, b.p.68 186-189°. These and other glycerols result
upon oxidizing unsaturated alcohols with potassium permanganate (B. 27, R.
165 ; 28, R. 927). Pentaglycerol, CH3C(CH2OH)3, m.p. 199°, is obtained
by the action of lime on propyl aldehyde and formaldehyde (A. 276, 76).
Dimethyl Pentaglycerol, (CH3)2CHC(CH2OH)3, m.p. 83°, is prepared from iso-
valeraldehyde and formaldehyde by the action of lime (B. 36, 1341). These
substances are triprimary glycerols.
[i,4,5-Hexanetrio[], CH3.CH(OH).CH(OH).CH2.CH2.CH2OH, b.p.10 181°, and
some other isomers and higher homologues have been obtained from the
addition products of bromine and hypochlorous acid with the corresponding
unsaturated alcohols.
GLYCEROL ESTERS OF INORGANIC ACIDS 529
A. GLYCEROL ESTERS OF INORGANIC ACIDS
(a) Glycerol Haloid Esters.— These are called halohydrins (p. 124). There
are two possible isomeric mono- and di-halohydrins. They are distinguished
as a-halohydrins and /3-halohydrins :
CH2C1 CH2OH CH2C1 CHtOH
CHOH CHC1 CHOH CHC1 '
CHaOH CHaOH CH2C1 CH2C1
o-Chlorhydrin. 0-Chlorhydrin. «-Dichlorhydrin. 0-Dichlorhydrin.
The monohalohydrins may also be regarded as halogen substitution products
of propylene and trimethylene glycol, whilst the dihalohydrins are probably the
dihalogen substitution products of propyl and isopropyl alcohol (p. 117).
a-Monohalohydrins are formed when the halogen acids act on glycerol, and by
andClOH (C. 1897, 1.741).
a-Dihalohydrins are produced when the halogen acids (A. 208, 349) act on
glycerol, and on the epihalohydrins (p. 532) (B. 10, 557). Potassium iodide
changes the chlorine derivative into the iodine compound.
a-Dichlorhydrin, CH2Cl.CHOH.CHaCl, b.p. 174°, D19 = 1-367, is a liquid, with
ethereal odour. It is not very soluble in water, but dissolves readily in alcohol
and ether. When heated with hydriodic acid it becomes converted into isopropyl
iodide ; sodium amalgam produces isopropyl alcohol. When sodium acts on
an ethereal solution of a-dichlorhydrin, we do not get trimethylene alcohol,
but ally! alcohol as a result of molecular transposition (B. 21, 1289). Chromic
acid oxidizes it to ^S-dichloracetone (p. 224) and chloracetic acid. Potassium
hydroxide converts it into epichlorhydrin (p. 532).
a-Dibrotnhydrin, CH2Br.CHOH.CHaBr, b.p. 219°; D1?=2'ii.
a-Di-iodhydrin, 0=2-4, solidifies at — 15°, is a thick oil.
It readily loses HI and polymerizes to ft-iodopropionaldehyde (C. 1900, II. 169).
fl-Ethyl 0,-Dichlorohydrin, C2H6C(OH)(CHaCl),, b.p.18 77°, is formed from sym.-
dichloracetone and ethyl magnesium bromide (C. 1906, I. 1471).
The /?-DihaIohydrins result from the addition of halogens to allyl alcohol.
p-Dichlorhydrin, b.p. 183°, Dc= 1-379, is converted by sodium into allyl alco-
hol. Hydriodic acid changes it to isopropyl iodide ; fuming nitric acid oxidizes
it to ajS-dichloropropionic acid.
Both dichlorhydrins are changed to epichlorhydrin by alkalis.
ft-Dibromhydrin, b.p. 212—214°.
Trihalohydrins are formed when halogens are added to the allyl halides;
also in the action of phosphorus halides on the dihalohydrins, and when iodine
chloride acts on propylene chloride, and bromine and iron on propylene bromide
and trimethylene bromide (B. 24, 4246).
Trichlorhydrin, Glyceryl Chloride, i,i,3-Trichloropropane, CHaCl.CHCl.CHaCl,
b.p. 158°.
Tribromhydrin, m.p. 16°, b.p. 220°, is converted by silver acetate into glycerol
triacetyl ester. When this is saponified it yields glycerol (p. 527).
(b) Glyeerol Esters of the Mineral Acids containing Oxygen. — The
neutral nitric acid ester (nitroglycerol) — nitroglycerine (discovered by
Sobrero in 1847) — is the most important member of this class.
Nitroglycerine, Glycerol Nitrate, CH2(ONOa).CH(ONOa).CHa(ONO2), m.p.
16°, D=ai-6, is produced by the action of a mixture of sulphuric and nitric acids
on glycerol. The latter is added, drop by drop, to a well-cooled mixture of
two parts of fuming nitric acid and three parts of concentrated sulphuric acid.
On standing the nitroglycerol rises, and, after separation, is poured into water.
VOL. I. 3 M
530 ORGANIC CHEMISTRY
The heavy oil (nitroglycerine) is washed with water and dried by means of calcium
Nitroglycerine is a colourless oil, which is easily volatilized at 160° (15 mm.
pressure) (B. 29, R. 41). It has an acrid taste, and is poisonous when taken
internally. It is sparingly soluble in water, dissolves with difficulty in cold alcohol,
but is easily soluble in wood spirit and ether. Heated quickly, or upon
percussion, it explodes very violently ; mixed with kieselguhr it forms dyna-
mite, and with nitrocellulose, smokeless powder.
Alkalis convert nitroglycerine into glycerol and nitric acid ; ammonium
sulphide also regenerates glycerol. Both reactions prove that nitroglycerine is
not a nitro-compound, but a nitric acid ester.
Partial nitration of glycerol or partial hydrolysis of nitroglycerine by dilute
sulphuric acid produces the two possible dinitroglycerines, C3H6(OH)(ONO2)a,
oils, which are not explosive; and also the two mononitroglycerines, C8H6(OH)2-
(ONO)a, m.ps. 59° and 54° ; these substances are easily soluble in water (B. 41,
1107).
Glycerol Nitrite, C3H5(O.NO)3, is formed by the action of N2O3 on glycerol.
It is isomeric with trinitropropane (B. 16, 1697).
Glycerol Sulphuric Acid, CH2OH.CHOH.CH2.OSO3H, is obtained from
glycerol and sulphuric acid. Propane-i,2,^-trisulphonic Acid, C3H6(SO2H)3, how-
ever, is formed from tribromhydrin and ammonium sulphite (C. 1904, II. 944)-
Glycerol Phosphoric Acid, C3H5<L pQjj , occurs combined with the fatty
acids and choline as lecithin (p. 531) in the yolk of eggs, in the brain, in the bile,
and in the nerve tissue. It is produced on mixing glycerol with metaphosphoric
acid. The free acid is a thick syrup, which decomposes into glycerol and phos-
phoric acid when it is heated with water. It yields easily soluble salts with two
equivalents of metal. The calcium salt is more insoluble in hot than in cold
water ; on boiling its solution, it is deposited in glistening leaflets (C. 1899, 1. 1 105).
For mono-acidic and neutral glycerol phosphate, C8H6.O3PO, see C. 1904, I. 431.
For the action of PC13 on glycerol, see C. 1902, I. 1048.
Glycerol mcrcaptans are produced when chlorhydrins are heated with alcoholic
solutions of potassium hydrosulphide.
B. GLYCEROL FATTY ACID ESTERS, GLYCERIDES
(a) Formic Acid Esters. Mono:ormin, C3H6(OH)2OCHO, is volatile under
diminished pressure. It is supposed that it is formed on heating oxalic acid and
glycerol. When it is heated alone it breaks down into allyl alcohol (p. 123),
water, and carbon dioxide. Diformin is most certainly produced under these
conditions. Monoformin also results from the action of fZ-monochlorhydrin on
sodium formate. Diformin, C3H6(OH).(O.CHO)2, b.p.20_30 163-166°.
(6) Acetic Esters, or Acetins, result when glycerol and acetic acid are heated
together (C. 1897, II. 474). Monacetin, b.p.2_3 131°. Diacetin, C3H6(O.COCH3)2-
(OH), b.p. 159° (B. 25, 3466). Triacetin, C8H6(O.COCH8)S, b.p. 258°, occurs
in small quantities in the seed of Euonymus europaus, and has also been
obtained from tribromhydrin (p. 529). Dichloromonacetin and monochlorodiacetin
(C. 1905, I. 12).
(c) Tributyrin, C,H6(OC4H7O),, b.p.10 185° (C. 1899, II. 21 ; 1900, II. 215),
occurs in cow's butter (p. 259).
(d) Glycerides of Higher Fatty Acids occur, as already stated (p. 264), in the
vegetable and animal fatty oils, fats, and tallows. They can be artificially
obtained by heating glycerol with the fatty acids (C. 1899, II. 20), or from tri-
bromhydrin and fatty acid salts (C. 1900, II. 215). The mono- and di-esters
(monostearin, dipalmitin, etc.) are prepared from mono- or di-chlorhydrins and
salts of the fatty acids, or by esterifying glycerol and the fatty acids by means of
concentrated sulphuric acid (C. 1903, I. 133 ; B. 38, 2284). If esterification is
completed with different acids mixed glycerides, such as palmitodistearin, are
formed, which occur to a certain extent in natural fats (B. 36, 2766).
Glycerides are very slightly soluble in cold alcohol, but easily so in ether.
They are saponified by alkalis or lead oxide (comp. p. 264) (C. 1899, II. 1699).
GLYCEROL ETHERS 531
When boiled with alcohols in presence of a little alkali or acid, the glycerides are,
to a great extent, converted into glycerol and fatty esters of the alcohols (C.
1907,1.151; 1908,1.1157; 11.495).
The most important glycerides are :
Trimyristin, or Myristin, Glycerol Myristic Ester, C3H5(O.C14H27O)3, m.p. 55°,
occurs in spermaceti, in nutmeg butter, and chiefly in oil nuts (from Myristica
surinamensis), from which it is most readily obtained (B. 18, 2011). It crystallizes
from ether in glistening needles. It yields myristic acid (p. 261 ) when saponified.
Tripalmitin, C3H5(O.CieH31O)3, m.p. (45°) 65°, is found in most fats,
especially in palm oil ; it can be separated from olive oil at low temperatures.
Tristearin, C3H5(O.C18H35O)3, m.p. (55°) 71-5°, occurs mainly in solid fats
(tallows). It can be obtained by heating glycerol and stearic acid to 280-300°.
It crystallizes from ether in shining leaflets.
On the phenomenon of the " double melting-point " of palmitin and stearin,
see C. 1902, I. 1196.
Triolein, or Ole'in, C3H?(O.ClgH33O)3, solidifies at —6°. It is found in oils,
like olive oil. It is oxidized on exposure to the air. Nitrous acid converts
it into the isomeric elaidin, m.p. 36° (p. 301).
Lecithins are widely distributed in the animal organism and occur especially
in the brain, in the nerves, the blood corpuscles, and the yolk of egg, from
which stearin-palmitic lecithin is most easily prepared. Lecithin occurs in the
seeds of plants (B. 29, 2761). It is a wax-like mass, easily soluble in alcohol and
ether, and crystallizes in fine needles. It swells up in water and forms an opalescent
solution, from which it is reprecipitated by various salts. It units with bases
and acids to salts, forming a sparingly soluble double salt, (C42H84NPO8.HC1)2.-
PtQ4, with platinic chloride. Lecithin is decomposed into choline, glycero-
phosphoric acid (see above), stearic acid, and palmitic acid, when it is boiled with
acids or barium hydroxide solution. Therefore we assume it to be an ethereal
compound of choline with glycerophosphoric acid, combined as glyceride with
stearic and palmitic acids :
CH2— O.COC17H8i
CH— O.COC15H81
(CH3)8\ TO" <-VT»
CH2— O.PO(OH).O.CH2CH2^>JN<UJrl
Lecithin is optically active — dextro-rotatory. When heated in alcoholic
solution to 90-100° it is racemized, and from this i-lecithin, l-lecithin can be
separated by lipase (C. 1901, II. 193 ; 1906, II. 493)-
The distearin and dioleo- compounds are also known. Protagon, a substance
obtained from the brain, appears to be closely related to the lecithins.
Glycerol Ethers : i. Alkyl Ethers.
Mixed ethers of glycerol with alcohol radicals are obtained by heating the
mono- and dichlorhydrins with sodium alcoholates.
Epichlorhydrin, sodium hydroxide solution, and an alcohol form glycerol
dialkyl ether (C. 1898, I. 237).
Monoethylin, CHaOH.CHOH.CH2OC2H5, b.p. 230°, is soluble in water.
Glycerol Dimethyl Ether, b.p. 169°. Diethylin, CH2OH.CH(OC2H?)CH2OC2H6,
b.p. 191°, dissolves with difficulty in water, and has an odour resembling that of
peppermint. Triethylin, C8H6(OC2H6)3, b.p. 185°, is insoluble in water.
Allylin, CH2OH.CHOH.CH2C3H6, b.p. 225-240°, is produced by heating
glycerol with oxalic acid (B. 14, 1946, 2270), and is present in the residue from
the preparation of allyl alcohol (p. 123). It is a thick liquid. Dtallyhn,
HO.C3H6(OC3H5)2, b.p. 225°-227, is produced when sodium allylate acts on
epichlorhydrin (B. 25, R. 506).
Dialkyl Ethers of Homologous Glycerols.
Fatty acid esters are condensed with chloromethyl alkyl ethers to form
dialkyl ethers of homologous glycerols by means of magnesium, which can be
rendered more active by means of HgCl2 (C. I9°7» J- 87r) :
RCOOC2H6+2ClMgCH2OC2H6 > RC(OH)(CH2OC2H6)2.
These diethylines yield acroleins, similarly to glycerol itself, when treated
532 ORGANIC CHEMISTRY
with oxalic acid : two molecules of alcohol are eliminated and a-alkyl acrolems
result (comp. p. 214).
Ethyl Glycerol Diethyl Ether, C2H5C(OH)(CH2OC2H6)a, b.p. 195°, is prepared
.«-«. ,^ .,;,-, ^o-t-n^ ^v.l/-kT-<->mofhTrl p+Vrul ^i-hpr pnrl mafnesiiim. Pvn-hvl fll'vr.p.vnl
XiH.-O.CH,
/CH2.O.CHa\ /
Glycerol Ether, CH^ O )CH or CHa /OCH, b.p. 171°, is
\CH2.O.CH/ \ / \
XCH — OCH,
formed when glycerol is heated to 270-330°, with a little ammonium chloride
(A. 335, 209) ; also, together with diallylin, from epichlorhydrin and sodium
allylate (see above). It is readily soluble in water, and is hydrolyzed with
difficulty.
An isomeric substance, m.p. 124°, has been obtained as a by-product of the
preparation of pyridine bases from glycerol and ammonium phosphate (comp.
p. 528) (C. 1897, I. 583).
Glycerol derivatives resemblingtheacetalsare formed when formaldehyde, acet-
aldehyde, acrolem, benzaldehyde, or acetone act on glycerol hot, or in presence of
/O.CH, /O.CHax
hydrochloric acid. Formal Glycerol, CH / \ orCH2< >CHOH«
XO.CH.CH2OH XO.CH/
b.p. 193° (A. 289, 29 ; 335, 209). Acetal Glycerol, HOCSH6O2>CHCH8, b.p.lt
86*. a-Acrolein Glycerol, HO.C3H6O2>CH.CH:CH2, is isomeric with glycerol
ether or jS-acrolein giycerol (q.v.). Benzal Glycerol, HOC3H6O2>CHC6H5, m.p.
66°. Acetone Glycerol, HOC3H5O2>C(CH3)2, b.p.n 83° (B. 27, 1536 ; 28, 1169).
xCH.CHaOH
Glycide Compounds: Glycide, Epihydrin Alcohol, Oc | , b.p. 162°,
XCH?
D0 = i'i65, is isomeric with acetyl carbinol (p. 341). This body shows the
properties both of ethylene oxide and of ethyl alcohol. It is obtained from its
acetate by the action of sodium hydroxide or barium hydroxide. Glycide and
its acetate reduce ammoniacal silver solutions at ordinary temperatures.
Glycerol also forms polyglycerols. Thus glycerol yields Diglycerol, (HO)a.C8-
H8OC3H6(OH)2, when it is treated with chlorhydrin or aqueous hydrochloric acid at
CH2— O— CH.CHjOH ,
130°. The polymer of glycide, Diglycide - • (?),
JtlU — L/rl 2 — Url U — Uxl 2
results from the action of sodium acetate on epichlorhydrin in absolute alcohol,
and the subsequent hydrolysis of diglycide acetate with sodium hydroxide.
XCH.CH2C1.
Epichlorhydrin, O<( b.p. 117°, D0=i-203, is isomeric with mono-
NCH,
chloracetone, and constitutes the parent substance for the preparation of the
glycide compounds, It is obtained from both dichlorhydrins by the action
of alkali hydroxides (analogous to the formation of ethylene oxide from glycol
chlorhydrin) (p. 319) : '
C1CH2.CHOH C1CH2.CH v C1CH.CH2C1
CH2C1 CH2/ HOCH8
It is a very mobile liquid, insoluble in water. Its odour resembles that of
chloroform, and its taste is sweetish and burning. It forms a-dichlorhydrin with
concentrated hydrochloric acid. PC16 converts it into trichlorhydrin. Con-
tinued heating with water to 180° changes it to a-monochlorhydrin. Con-
centrated nitric acid oxidizes it to j8-chlorolactic acid. Metallic sodium converts
it into sodium allylate, CHa=CH.CH jONa.
DIHYDROXY-ALDEHYDES 533
Like ethylene oxide, epichlorhydrin combines with HNC to the hydroxy-
cyanide,
Epibromhydrin, C3H6OBr, b.p. 130-140°, is prepared from the dibrom
hydrin.
Epi-iodohydrin, C8HSOI, b.p.12 62°, is prepared from epichlorhydrin by the
action of KI and alcohol, and subsequent treatment with aqueous alkali hydroxides.
Epihydrin- ether, [O<C3H5]2O, b.p.22 103°, is produced from the above by means
of silver oxide; and Nitroglycide, NO2.OC3H6>O, b.p.15 63°, by silver nitrate.
It also results when alkali acts on either of the two dinitroglycerols (p. 510)
(A. 335, 238; B. 41, 1117).
Di-epi-iodohydrin, ICH2.CH/°~^a^CH.CH2I, m.p. 160°, is formed
when iodine acts on mercury allyl alcohol iodide, (C3H6O.HgI)2. This body, as
well as mercury propylene-glycol iodide, IHg.CH2CH(OH)CHaOH, is also obtained
from allyl alcohol and mercury salts (comp. Mercury Ethanol Iodide, p. 326)
(6.34,1385,2911).
Epiethylin, Ethyl Glycide Ether, O<C8H6.OC2H6, b.p. 129°, and Amyl
Glycide Ether, b.p. 188°, are produced from the respective ethers of chlorhydrin
by distillation with potassium hydroxide (A. 335, 231). Glycide Acetate,
O<C8H6.OCOCH3, b.p. 169°, is formed from epichlorhydrin and anhydrous
potassium acetate.
Nitrogen Derivatives of the Glycerols.
Nitroisobutyl Glycol, CH3C.(tfO2)(CH2OH)a, b.p. 140°, is formed from nitro-
ethane and formaldehyde (B. 28, R. 774).
i-Aminopropane Dial, NH,.CH2CH(OH)CH2OH, b.p.m 238°, is formed
from glycide and aqueous ammonia. Similarly, the i-alkyl aminopropane dials
can be prepared ; tertiary amines react with glycerol a-chlorhydrin to form
quaternary ammonium chlorides, e.g. (C8H6)8N(C1)CH2CHOH.CH2OH (B. 33,
3500). 2-Aminopropane Diol, HOCH2.CH(NHa).CH2OH, is formed when
dihydroxyacetone oxime is reduced (B. 32, 751).
2- Amino-tert. -butane Diol, CH3C(NH2)(CH2OH)2 (C. 1908, I. 816).
From i,3-Diamino-2-propanol is derived the local anaesthetic Alypin,
C6H6CO.OCH[CH2N(CH3)2]2 (C. 1905, II. 1551); also i.^-Dianilinopropanol,
(CflH6NHCH2)2CHOH, from aniline and epichlorhydrin (B. 37, 3034); also,
finally, Trimethylene-imino-2-sulphonic acid. This substance is obtained from
bromomethyl taurine, a decomposition product of the thiazoline derivative obtained
from allyl-mustard oil dibromide (B. 39, 2891).
BrCH,.CH— Sv O BrCHa.CHSO8H _HBr CHa— CHSO,H
\CCR - > | - > | |
-N/' CH2.NH2 NH— CH2
Triaminopropane, CH2NH2.CHNH2,CH2NHS, b.p.9 93°, is prepared from
Glycerol Triurethane, C8H6(NHCO2C2H6)3, m.p. 92°, which is formed from the
action of absolute alcohol on the triazide of tricar ball vlic acid (J. pr. Ch. [2]
62, 240).
i,3-Tetramethyl-diamino-2-nitropropane, [(CH3)2N.CH2]2.CHNO2, or [(CH8)2-
NCH2]2C: NOOH, m.p. 58°, is prepared from 2 molecules of methanol-
dimethylamine, (CH8)2NCH2OH, and nitromethane. It forms salts both with
acids and alkalis (comp. Nitromethane, p. 151). When boiled with water it is
decomposed to formaldehyde ; with aqueous aniline it forms Dianilinonitro-
propane, (C,H6NHCH2)2CHNO2 ; by reduction with tin chloride it yields Tetra-
methyl-i,3,2-triamino-propane, [(CH8)2NCHa]2CHNHj, b.p. 175° (B. 38, 2037).
2. DIHYDROXY-ALDEHYDES.
Glycerol Aldehyde [Propane Diolal], CH2OH.CHOH.CHO, m.p. 138', is pre-
pared in the pure state by hydrolysis of its acetal (see below) with dilute sulphuric
acid. When treated with alcohol and hydrochloric acid, it is reconverted into
the parent substance. It crystalizes in needles from dilute methyl alcohol,
and is almost insoluble in alcohol and ether. It reduces Fehling's solution in
the cold, and forms a characteristic compound with phloroglucinol (Vol. II.) with
534 ORGANIC CHEMISTRY
loss of water. The Glycerol Acetal, CH2OH.CHOH.CH(OC2H$)a, b.p.81 130°, is
best obtained by oxidation of acrolem acetal (p. 215) with permanganate.
Glycerol Aldehyde Oxime, CH2OH.CHOH.CH : NOH, is an oil. When warmed
with alkalis it loses water and hydrocyanic acid, forming glycol aldehyde (p. 337)
(comp. the carbohydrates). In the solid form both glycol aldehyde and glycerol
aldehyde are apparently to be looked on as dimolecular polymers (B. 33, 3095).
2-Chloro-3-hydroxy-propionacetal, CH2(OH).CHC1.CH(OCH3)2, b.p.n 98°, is
formed from acrolem acetal and HC1O. Oxidation converts it into 2-chloro-
3-dimethoxy-propionic acid, (CH3O)2CH.CHC1COOH ; reaction with ammonia
produces -z-Hydroxy-^-amino-propionacetal, CH2(NH2).CH(OH)CH(OCH8)2, m.p.
55-58°, b.p.n in0, with intermediate formation of open ethylenoxy-com-
pound. This acetal gives rise to the hydrochloride of fi-Aminolactic Aldehyde,
NH2CH2CH(OH)CHO, which, on oxidation yields isoserine (p. 541) (B. 40, 92).
A mixture of a little glycerol aldehyde with glycerol ketone or dihydroxy-
acetone (see below) is formed by the oxidation of glycerol with dilute nitric acid,
bromine or hydrogen peroxide in presence of a little ferrous sulphate (C. 1888,
II. 104 ; B. 33, 3098). It is known as glycerose, and is condensed by sodium
hydroxide to inactive acrose. This compound is related to dextrose, which can
also be formed from each of the two separate compounds above mentioned.
Methyl Glycerol Aldehyde, CH3CH(OH).CH(OH)CHO, is a syrupy body
formed, analogously to glycerol aldehyde, from its acetal, CH3CH(OH)CH(OH)-
CH(OC2H6)2, the oxidation product of croton aldehyde acetal (B. 35, 1914).
Pentaglycerol, Aldehyde, CH3C(CH2OH)2CHO, is prepared by condensing
propionaldehyde with two molecules of formaldehyde. Hexyl Glycerol Aldehyde,
(CH3)2C(OH)CH(OH)CHaCHO, is obtained by condensation of d-hydroxy-
isobutyric aldehyde with acetaldehyde (M. 22, 443, 527).
Chloral Aldol, CC13.CH(OH).CH(CHO).CHOH.CH3< and Butyl Chloral Aldol,
CH3.CHC1.CC12.CH(OH).CH(CHO).CHOH.CH3, are thick oils. They result
from the condensation of chloral or butyl chloral with paraldehyde and
glacial acetic acid (B. 25, 798).
3. DIHYDROXY-KETONES (OXETONES)
Dihydroxy acetone, Glycerol Ketone [Propane Diolone], CH2OH.CO.CH2OH,
m.p. 68—75°, is prepared from its oxime by the action of bromine (p. 527). It
tastes sweet and cooling. Water, alcohol, and acetone dissolve it easily, ether
with difficulty. Reduction (p. 527) and the action of the sorbose bacterium
(C. 1898, I. 985) convert it into glycerol (see also Glycerose, above). It reduces
Fehling's solution in the cold. The oxime, CH2OH.C=N(OH).CH2OH, m.p.
84°, is produced from hydroxylamino-tert.-butyl-glycerol by HgO (B. 30, 3161).
Chloracetyl Carbinol, C1CH2.CO.CH?OH, m.p. 74°, is formed from allene (p. 90)
and HC1O, together with some dichloracetone (C. 1904, I. 576). Diethoxy-
acetone, (C2H6O)CH2.CO.CH2(OC2H6), b.p. 195°, is prepared from ay-diethoxy-
acetoacetic ester, and by distillation of calcium ethyl glycollate (B. 28, R. 295).
Diaminoacetone, NHaCH2.CO.CH2NH2, is obtained by the reduction of di-
isonitroso-acetone (B. 28, 1519). 2,2-Nitro-bromo-trimethylene Glycol [2,2-Nitro-
bromo-propane-diol\t HO.CH2CBr(NO2).CH2OH, m.p. 106°, is prepared from
bromonitromethane and formaldehyde (C. 1899, !• *79)«
Homologous Dihydroxyketones.
Trimethyl Triose, (CH3)2C(OH).CH(OH)COCH8, b.p.1$ 109°, is obtained by
the oxidation of mesityl oxide, (CH8)2C : CHCOCH3 (p. 229), by permanganate,
and appears to decompose rapidly into acetone and acetol. Dihydroxy-dihydro-
methyl-heptenonc, (CH3)2C(OH)CH(OH)CHaCH2COCH8> m.p. 67°, is similarly
prepared from methyl heptenone (p. 232) and permanganate (B. 34, 2979 ; 35,
1181). y%-Dihydroxy-butyl-methyl Ketone, CH2(OH)CH(OH)CH2CH2COCH8,
b.p. 22 190°, results from the splitting up of a-acetyl-8-chloro-y-valerol acetone
(the condensation product of epichlorhydrin and acetoacetic ester) by means of
potassium carbonate (B. 34, 1981). It is similarly prepared from epichlorhydrin
and sodium acetyl acetone (C. 1904, I. 356).
Derivatives of Triacetone Dialcohol, £*
is as yet unknown) are compounds, discussed" in connection witlT phorone (p. 229),
HYDROXY-DIALDEHYDES 535
such as triacetonamine, triacetone diamine, triacetone hydroxylamine, triacetone
dihydroxylamine, their anhydrides and dmitroso-di-isopropyl-acetone. Similar
compounds when treated with ammonia, also yield, in part, methyl ethyl ketone
p. 224). Trimethyl Diethyl Ketopiperidine,
m.p. 247°, corresponding with triacetonamine (B. 41, 777).
The oxetones, discovered by Fittig, may be considered as the anhydrides of
the yy-dihydroxyketones. Their constitution is indicated by the formation of
dimethyl oxetone by treatment of the addition product of dialkyl acetone with
two molcules of HBr with potash solution ( Volhard, A. 267, 90) :
Br Br
HaO
CH8CHCH2CHa.CO.CH2CH2CHCH3 >
:3CHCH2CH2.C.CH2CH2CHCH3
The oxetones are obtained from the condensation products of the y-lactones
with sodium ethoxide in consequence of the elimination of carbon dioxide (see
P- 374)-
Oxetone, C7H12OZ, b.p. I59'4°- Dimethyl Oxetone, C9H16O2, b.p. 169*5°,
D0 = o-978. Diethyl Oxetone, CUH20O2, b.p. 209°. These oxetones are mobile
liquids, and possess an agreeable odour. They are not very soluble in water,
reduce an ammoniacal silver solution, and combine with 2HBr to y-dibromo-
ketones.
/-ITT _ PT-T
y-Pyrone, CO<~->O, mav be considered the anhydride of an unsatu-
and
rated dihydroxyketone.
4. HYDROXY-DIALDEHYDES
Nitromalonic Dialdehyde, NO2CH(CHO)2, or HO2N : C(CHO)2, m.p. 50*,
is a derivative of the dialdehyde of tartronic or hydroxymalonic acid. Its sodium
salt is prepared from mucobromic acid (p. 402) and sodium nitrite (comp. C.
1900, II. 1262). The free aldehyde is obtained from the silver salt by hydro-
chloric acid, in ethereal solution. In aqueous solution it changes into formic
acid and sym.-trinitrobenzene (Vol. II.). It condenses with acetone in alkaline
solution to form £-nitrophenol, and behaves similarly with a series of other
ketones, ketonic acid esters, etc. (C. 1899, II. 609; 1900, II. 560). Hydroxyl-
xCH =N
amine converts nitromalonic aldehyde into mtro-isoxazole, NO2C^ j ,
salts of the unstable nttromalonic aldehyde dioxime, MeO2N.C(CH : NOH),,
which can be converted into nitromalonic aldoxime nitrile, NO2HC(CN)CH : NOH,
andfulminuric acid, NO2HC(CN)CONH2 (C. 1903, I. 957)-
Chloromalonic Dialdehyde, C1CH(CHO)2 or CHO.CC1 : CHOH, m.p. 144*,
with decomposition, and
Bromomalonic Dialdehyde, BrC3H3O2, m.p. 140°, with decomposition, are
prepared from nitromalonic aldehyde and mucochloric and mucobromic acids.
Aniline causes the loss of CO2 and converts them into dianils of the dialdehydes,
which are liberated by hydrolysis :
CC1CHO -C02 CC1.CH:N,CH5 2H2O CC1CHO
H02CCC1 HCNHC,H, HCOH
The two dialdehydes are also formed from ethoxyacrolem acetal
(CtH5O)CH : CH.CH(OC2H6)2 (see Malonic Dialdehyde, p. 347), by chlorine
and bromine. The ewoJ-configuration (see above) gives rise to strongly acid
bodies giving a reddish- violet coloration with ferric chloride. Their stability
towards alkalis is remarkable. Hydrazines give rise to pyrazoles (B. 37, 4638).
536 ORGANIC CHEMISTRY
5. HYDROXY-ALDEHYDE KETONES
Hydroxypyroracemic Aldehyde, CHO.CO.CH8OH, m.p. 134°, is the simplest
hydroxyaldehyde ketone. It is only known in the form of its osazone, and is
produced by the interaction of phenylhydrazine and dihydroxyacetone (B. 28,
1522).
Propanone Trisulphomc Acid, (SO3H)2CHCOCH2(SO3H), is a derivative of
hydroxypyroracemic acid, prepared by the action of fuming sulphuric acid on
acetone. It is decomposed by alkalis into methionic and sulphoacetic acid (C.
1902, I. 101).
6. HYDROXY-DIKETONES
afi-Diketo-butyl Alcohol, CH,CO.COCH2OH, is the simplest hypothetical
hydroxydiketone. A derivative is a-Dibromethyl Ketol, CH,CBr2.CO.CH2OH,
m.p. 85°, prepared from bromotetrinic acid (p. 544) and bromine.
Derivatives of a body, (CH3)2C(OH)COCOCH3, are found among the reaction
products of nitrous or nitric acid on mesityl oxide oxime (p. 231).
i-Ethoxy acetyl Acetone, (C2H6O)CH2COCH2COCH3, b.p.13 84°, is prepared
from ethoxyacetic ester, sodium, and acetone (comp. p. 350) (C. 1907, I. 871).
•$-Amino acetyl Acetone, (CH3CO)2CHNH2, is formed when isonitroso-acetyl
acetone is reduced. Nitrous acid converts it into Dimethyl Diacetyl Pyrazine (i),
m.p. 99°, and a diazo-anhydride or furo[a.b]diazole (2), of which the connecting
oxygen is easily replaceable by NR and S (see Vol. II. ; Pyrro[&b]diazoles and
Thio[zb]diazoles) (A. 325, 129) :
CH.C— N— C.COCH3 CH8C— (X
(i) II I II (2) || >N
CH,COC— N— CCH, CH,COC— N^
Hydroxymethylene Acetyl Acetone, (CH3CO)2C=CHOH, m.p. 47°, b.p. 199°,
which is the aci- or enol-iorm of sym.-Formyl Acetyl Acetone, Formyl Diacetyl
'Methane, (CH3CO)2CH.CHO, is a stronger acid than acetic acid, and soluble in
aqueous alkali acetates. It readily absorbs oxygen from the air, and is decom-
posed by gentle heating with water and HgO into COt and acetyl acetone ;
" copper salt, m.p. 214°.
Ethoxymethylene Acetyl Acetone, (CH,CO)2C=CH(OC2H5), b.p.ie 141°, is
formed by condensation of acetyl acetone with orthoformic ether by acetic
anhydride. It decomposes with water into alcohol and the previous substance.
It combines with acetyl acetone to form Methenyl-bis-acetyl Acetone,(CH3CO}2C=
. CH — CH(COCH3)2, m.p. 118°, which is easily changed by ammonia into di-
acetyl lutidine (Vol. II.), and by abstraction of water into diacetyl w-cresol.
Aminomethylene Acetyl Acetone, (CH8CO)2C : CHNH2, m.p. 144°, is formed
from ethoxymethylene acetyl acetone and ammonia. Anilinomethylene Acetyl
Acetone, (CH3CO)2C : CHNHCCH5, m.p. 90°, results when diphenyl fonnamidine,
C8H5N : CH.NHC0H5, is heated with acetyl acetone (B. 35, 2505).
Hydroxymethylene acetyl acetone, as well as the corresponding derivatives
of acetoacetic ester and malonic ester, can be considered as being formic acid
in which the intra-radical oxygen has been replaced by a carbon atom carrying
two negative groups (X) :
O=CH.OH ^>C=CH.OH.
Formic Acid. Hydroxymethylene Compounds^
As these bodies are strong monobasic acids, the group X2C= would seem
to exert an influence on the carbon atom combined with it, or on the hydroxyl
, m union with the carbon atom, just as is done by oxygen that is joined with two
bonds, but the influence may not be as great as in the latter case. The com-
pounds just described are the first of the complex substances, containing only
u, tt and O, which, without carboxyl, still approach the monocarboxylic acids
n acidity. Indeed, in some instances they surpass them in this respect (B. 26,
2731 ; L. Claisen, A. 297, i).
TRIKE10NES 537
7. DIALDEHYDE KETONES
Mesoxalic Dialdehyde, CHO.CO.CHO, is formed, together with acetone
peroxide, when phorone ozonide (p. 229), (CH3)2C(O3)CHCOCH(O3)C(CH3)2, is
shaken with water, and the aqueous solution concentrated. It may be in the
form of a syrup, the hydrate, solidifying to a glass-like substance, or a loose
light yellow powder (a polymerized body), which, in aqueous solution, is strongly
reducing in its action. The diphenylhydrazone, CO[CH : NNHC,H5],, m.p. 175°
with decomposition, is formed by the action of phenylhydrazine, and also from
acetone dicarboxylic acid (p. 568) with diazobenzene ; the triphenylhydrazone,
C6H5NHN : C[CH : NNHC6H812, m.p. 166°, may be prepared (B. 38, 1634).
The Dioxime, Di-isonitroso-acetone, CO[CH : NOH]2, m.p. 144", with decom-
position, is formed from acetone dicarboxylic acid and nitric acid ; further action
of N2O3 produces mesoxalic dialdehyde. The trioxime, trioximidopropane,
HON : C[CH : NOH],, m.p. 171°, is formed by means of hydroxylamine (B. 38,
1372).
8. ALDEHYDE DIKETONES
See above, under hydroxymethylene acetyl acetone or zci-formyl diacetyl
methane (p. 536).
9. TRI KETONES
Related Triketones are obtained from the i,3-diketones by means of nitroso-
dimethyl-aniline, followed by decomposition of the resulting dimethyl amido-acid
by dilute sulphuric acid (B. 40, 2714) :
NOC6H4N(CH3)a H2O
(CH3CO)2CH2 - --»• (CH3CO)2C : NCaH4N(CH3)2 — -»• (CH8CO)2CO.
These tri-ketones are orange-red oils which form colourless hydrates with
water. They are very strongly reducing bodies, and indicate a relationship with
animal hairs.
Triketopentane [Pentane-2,3,4-trione], CH3CO.CO.COCH8, b.p.8(, 65-70°, is
formed by decomposing the reaction product of nitroso-dimethyl-aniline (Vol. II.)
and acetyl acetone. It is an orange-yellow oil, which unites with water to form a
colourless crystalline hydrate, C6H,O84-H2O. The phenylhydrazone, benzene
azo-acetyl acetone, C6H6NHN : C(COCH3)2, and the oxime, isonitroso-acetyl acetone,
HON : C(COCH3)2, m.p. 75", are prepared from sodium acetyl acetone and diazo-
benzene salts or nitrous acid (A. 325, 139, 193). Triketopentane and phenyl-
hydrazine form a bis-phenylhydrazone ; with semicarbazide a bis-semicarbazone,
m.p. 221° ; with hydrazine hydrate, dimethyl-hydroxy-pyrazole (comp. i,3-diketone,
P- 350) I with o-phenylene diamine, a quinoxaline-derivative (comp. i,2-diketone,
p. 348). Alkalis decompose triketopentane into 2 molecules of acetic acid and
formaldehyde.
2,3,4-Triketohexane, CH8CO.CO.COC2H5, b.p.ls 70°, is obtained, analogously
to triketopentane, from acetyl methyl ethyl ketone, CH8COCH2.COC2HS
(B. 40, 2728).
2,3,5-Triketohexane. The trioxime, CH3C(NOH)CH2C(NOH)C(NOH)CH8, m.p.
159°, is formed, similarly to succinic dialdoxime from pyrrole (p. 355), and from
/3-nitroso-oa, -dimethyl-pyrrole and hydroxylamine (C. 1908, I. 1630).
Diacetyl Acetone, 2,^,6-Triketoheptane, [2,4,6-Heptane Trione], CO(CH,CO-
CH8)2, m.p. 49°, is produced from 2,6-dimethyl pyrone, CO^H
end concentrated barium hydroxide solution, from which it is separated by hydro-
chloric acid. It decomposes spontaneously into water and dimethyl pyrone (A.
257, 276). Ferric chloride produces a deep red colour with it. The oxime, m.p.
68°, easily turns into an anhydride (B. 28, 1817). With sodium and iodomethane
it is converted into a Dimethyl Diacetyl Acetone, m.p. 87° (C. 1900, II. 625)*
Acetonyl Acetyl Acetone, CH8COCH2.CH(COCH8)2, b.p.,, 156°, is formed from
•odium acetyl acetone and chloracetone (C. 1902, II. 346).
538 ORGANIC CHEMISTRY
10. DIHYDROXY-MONOCARBOXYLIC ACIDS
The acids of this series bear the same relation to the glycerols that
the lactic acids sustain to the glycols, and may also be looked on as
being dihydroxy-derivatives of the fatty acids. They may be arti-
ficially prepared by means of the general methods used in the pro-
duction of hydroxacids, and also by the oxidation of unsaturated acids
with potassium permanganate (p. 293) (B. 21, R. 660 ; A. 283, 109).
Glyceric Acid, C3H604, Dihydroxypropionic Acid, [Propanediol
Acid], is formed : (i) By the careful oxidation of glycerol with nitric
acid (method of preparation, B. 9, 1902, 10, 267 ; 15, 2071) ; or by
oxidizing glycerol with mercuric oxide and barium hydroxide solu-
tion (B. 18, 3357), or with silver chloride and sodium hydroxide (B.
29, R. 545), or with red lead and nitric acid (C. 1898, I. 26). The
calcium salt is decomposed with oxalic acid (B. 24, R. 653) :
CHt(OH).CH(OH).CH2.OH+O2=CHa(OH).CH(OH).CO.OH+H8O.
(2) By the action of silver oxide on j8-chlorolactic acid, CH2CL-
CH(OH).C02H, and a-chlorohydracrylic acid, CH2(OH).CHC1.CO2H
(p. 368). (3) By heating glycidic acid with water (p. 539).
Glyceric acid forms a syrup which cannot be crystallized. It is
easily soluble in water, alcohol, and acetone. It is optically inactive,
but as it contains an asymmetric carbon atom (p. 29), it may be
changed to active laevo-rotatory glyceric acid by the fermentation
of its ammonium salt, through the agency of Penicillium glaucum.
Bacillus ethaceticus, on the other hand, decomposes inactive givceric
acid so that the laevo-rotatory glyceric acid is destroyed and the
dextro-rotatory acid remains (B. 24, R. 635, 673). This glyceric acid
is also formed by reduction of hydroxypyroracemic acid (p. 543),
whilst the 1-glyceric acid is obtained by the action of milk of lime on
glycuronic acid. Further, both forms can be separated by means of
brucine (B. 37, 339 ; C. 1905, I. 1085, 1089).
Reactions. — When the acid is heated above 140° it decomposes
into water, pyroracemic and pyrotartaric acids. When fused with
potassium hydroxide it forms acetic and formic acids, and when boiled
with it, yields oxalic and lactic acids. Phosphorus iodide converts
it into j3-iodopropionic acid. Heated with hydrochloric acid, it yields
a-chlorohydracrylic acid and aj^-dichloropropionic acid. (See also
j3-chlorolactic acid (p. 368).)
When glyceric acid is kept, it probably forms a lactide or anhydride. This
is sparingly soluble in water, and crystallizes in fine needles.
Salts and Esters. — Its calcium salt, (C8H5O4)sCa+2HaO, dissolves readily in
water ; lead salt, (C3H6O4)2Pb, is not very soluble in water ; ethyl ester is formed
on heating glyceric acid with absolute alcohol. The rotatory power of the
optically active glyceric esters increases with the molecular weight (B. 26, R.
540), and attains its maximum with the butyl ester (B. 27, R. 137, 138 ; C. 1897,
I. 970).
The homologues of glyceric acid (Dihydroxy-acids with adjacent hydroxyl groups)
have been obtained (i) from the corresponding dibromo-fatty acids ; (2) from the
corresponding glycidic acids on heating them with water (A. 234, 197) ; and
(3) by oxidizing the corresponding unsaturated carboxylic acids (p. 293) with
potassium permanganate or persulphuric acid, which at the same time occasion
DIHYDROXY-MONOCARBOXYLIC ACIDS 539
stereoisomeric transformation (comp. Dihydroxystearic Acid) (A. 268, 8 ; B. 22,
R. 743 ; C. 1903, I. 319).
ap-Dlhydroxybiityric Acid, fi-Methyl Glyceric Acid, CH3CH(OH)CH(OH)CO2H,
m.p. 75°, is resolved from the mixture of its optically active components
by quinidine. Also, the a-form appears to result from oxycellulose by the
action of milk of lime (B. 32, 2598 ; C. 1904, I. 933). aft-Dihydroxyisobutyric
Acid, a-Methyl Glyceric Acid, CH2OH.C(CH3)(OH)CO2H, m.p. 100°. Triglyceric
Acid, m.p. 88°. Anglyceric Acid, m.p. 111° (A. 283, 109). a-Ethyl Glyceric
Acid, m.p. 99°. a-Propyl Glyceric Acid, m.p. 94°. a-Isopropyl Glyceric Acid,
m.p. 102° (C. 1899, I. 1071). a-Ethyl ft -Methyl Glyceric Acid, Isohexeric Acid,
CH3CH(OH)C(C2H6)(OH)COOH, m.p. 145°, is formed from a-ethyl crotonic
acid (A. 334, 68).
apDihydroxyiso-octylic Acid, (CH8)2CHCH2CH2CH(OH)CH(OH)CO2H, m.p.
106° (A. 283,291).
a-Isopropyl ^ -I sobuty I Glyceric Acid, m.p. 154° (B. 29, 508).
py-pihydroxybutyric Acid, Butyl Glyceric Acid, CH2(OH).CH(OH)CH2CO2H,
is a thick oil. The fty-dihalogen and hydroxy-halogen-butyric acids corresponding
with these, are obtained from vinyl acetic acid (p. 297.), or from epihalogen hydrins
(p. 532), and hydrocyanic acid; y-Ethoxy-d-hydroxy-butyric Acid is a syrup;
ethyl ester, b.p.18 121° ; nitrite, b.p. 245°, is prepared from epiethylin (p. 533)
and hydrocyanic acid (C. 1903, II. 106 ; 1905, I. 1586).
y%-Dihydroxyvaleric Acid, CH2(OH)CH(OH)CH2CH2CO2H, rapidly decom-
poses into water and forms hydroxylactone.
Dihydroxyundecylic Acid, CUH22(OH)2O2, m.p. 85°, is prepared from unde-
cylenic acid (p. 299). Dihydroxystearic Acid, C18H34(OH)2O2 (see Oleic and
Elai'dic Acids, p. 300) (C. 1902, I. 179 ; 1903, I. 319). Dihydroxybehenic Acid,
C22H42(OH)2O2, m.p. 127°, is formed from erucic acid, C22H42O2.
Glycidic Acids are formed (i) by the action of alcoholic potassium hydroxide
on the addition product of hypochlorous and define carboxylic acids (A. 266,
204) ; (2) by condensation of ketones and a-halogen fatty esters by sodium
ethoxide or sodium amide, whereby the glycidic esters are formed :
(CH3)C20 +NaNH2 r(CH8)2C.ONa-| (CH8)2(
CO2R.CH2C1~~ *" L CO2R.CHC1 J CO2R.CH'
The acids obtained from these esters easily lose CO2 and change into aldehydes
or ketones (C. 1906, I. 669 ; B. 38, 699).
In general, the glycidic acids, like ethylene oxide, form addition products
with the halogen acids, water and ammonia, whereby chloro-hydroxy fatty acids,
dihydroxy, and amino-hydroxy-fatty acids can be prepared. Many add sodium
malonic ester, etc. (C. 1906, II. 421).
XCHCO2H
Glycidic Acid, Epihydrinic Acid, O<^ | , is isomeric with pyroracemic
acid. It is produced, like epichlorhydrin (p. 532), from a-chlorhydracrylic acid
and /J-chlorolactic acid by means of alcoholic potassium hydroxide. Glycidic
acid, separated from its salts by means of sulphuric acid, is a mobile liquid miscible
with water, alcohol, and ether. It is very volatile and has a penetrating odour.
The free acid and its salts are not coloured red by iron sulphate solutions (dis-
tinction from isomeric pyroracemic acid). It combines with the halogen acids to
/? -halogen lactic acids, and with water, either on boiling 'or on standing, it yields
.glyceric acid. Its ethyl ester, m.p. 162°, obtained from the silver salt with ethyl
iodide, resembles malonic ester in its odour (B. 21, 2053).
p-Methyl Glycidic Acid, CH3CH.OCHCOOH, is known in two modifications.
The one, m.p. 84°, unites with water to qg-dihydroxybutyric acid. The other
modification is a liquid. Epihydrin Carboxylic Acid, CH2.O.CHCH2COOH,
m.p. 225°, is obtained from its nitrile, which results from the action of KCN on
epichlorhydrin (p. 532). a-Methyl Glycidic Acid, CH2.O.C(CH,)COOH, consists
.of shining leaflets. The ethyl ester, b.p. 162-164° (B. 21, 2054). ap-Dimethyl
Glycidic Acid, CK8CH.O.C(CH3)COOH, m.p. 62° (A. 257, 128).
540 ORGANIC CHEMISTRY
Pp-Dimethyl Glycidic Acid, (CH3)2C.O.CHCOOH, is formed as a syrup, from
a-chloro-/Miydroxy-iso valeric acid (A. 292,282) ; ethyl ester, b.p. i8x°, is obtained
in good yield from acetone, chloracetic ester and sodium amide (see above)
(B. 38, 707). pfi-Methyl Ethyl Glycidic Ester, b.p. 198° ; fifi-Diethyl Glycidic Ester,
b.p. 212° ; and fip-Trimethyl Glycidic Ester, b.p.20 81°, etc., are formed according
to method 2.
Hydroxylactones are formed from those dihydroxy acids in which the hydroxyl
group stands in the y-position to the carboxyl group. Thus, a-hydroxy-y -lac tones
are obtained by hydrolysis of cyanhydrins of the aldols (p. 338) :
CH3CH(OH)CH,CHOH CH8CH.CHaCHOH
CN O CO
HOCHaC(CH8),CHOH CH2C(CH8)tCHOH
CN O— —CO
These hydroxylactones are readily caused by acids to undergo isomeric
transformation accompanied by wandering of the OH-group ; in the case of
a-hydroxyoalerolactone (see above), the OH-group apparently migrates first to
the j8- and finally to the y-position, forming lasvulinic acid (p. 421) (A. 334, 68 ;
C. 1914, I. 217). On the other hand, the cyanhydrin of fi-chloro-diethyl-ketone
(p. 228) and alkali yield salts of Ethyl Trimethylene Oxide Carboxylic Acid:
I I
CtH6C(COOH).CH2.CH,O, b.p.lg 136° (C. 1908, I. 1615).
HO.CH2CH O
8-Hydroxyvalerolactone, \ \ , b.p. 300-301°, results from
CH2CH2— CO
the action of potassium permanganate on allyl acetic acid (A. 268, 61).
Hydroxycaprolactone and Hydroxyisocaprolactone, C6HIOO3, are colourless liquids,
into which the oxidation products of hydrosorbic acid by means of KMnO4
rapidly pass on liberation from their barium salts (A. 268, 34). Hydroxyiso-
heptolactone, (CH3)2CH.CH.CH(OH).CH2.COO, m.p. 112°. Hydroxyiso-octolactone,
(CH8)2CH.CH?.CH.CH(OH)CH8CO.O, m.p. 33° (A. 283, 278, 291).
The following section of the hydroxy-amino, thio-amino, and diamino-carboxylic
acids embraces a number of substances which, with the simple amino-acids
(pp. 381, 390), commands the greatest interest, as constituting the decomposi-
tion products of the proteins — serine, cystine, ornithine, arginine, proline,
lysine.
Monoamino-hydroxy-earboxylic Acids.
a-Aminohydracrylic Acid, a.-Amino-p-hydroxy-propionic Acid, HO.CHaCH-
(NH2)COOH, m.p. 246° with decomposition, has been named serine, because it
was first obtained from sericin (silk-gum). It is also obtained from silk-fibroin,
horn, gelatin, casein, etc., by hydrolysis with dilute acids. It was first synthesized
from glycolyl aldehyde (p. 337), ammonia, hydrocyanic acid, and hydrochloric acid
(B. 35, 3794) ; also, by the following steps : formic ester and hippuric ester were
condensed by sodium ethoxide to formyl hippuric ester, CHO.CH(NHCOC6H5)-
COOC2H, (p. 543), which, on reduction, yields benzoyl serine ester, HOCH2CH-
(NHCOC,H6)COOC?H8, m.p. 80° ; this, on hydrolysis, gives serine (A. 337, 222).
The best synthesis consists in preparing p-ethoxy-a-amino-propionic acid
CSH,OCH1.CH(NH1)COOH, m.p. 256° with decomposition, from ethoxyacetal-
dehyde (p. 338), NH$, HCN, and HC1, and decomposing this with hydrobromic
acid (B. 39, 2644).
Serine forms hard crystals, soluble in 24 parts of water at 20*, but insoluble
in alcohol and ether. As an amino-acid it reacts neutral, but forms salts with
bases and acids. The taste is sweet, like glycocoll.
Both synthetic and natural serine are optically inactive on account of racemiza-
tion ; resolution can be effected through the quinine salts of the p-nitrobenzoyl-
derivative into d- and \-serine, [a]D2o=+6<8°, m.p. 228° with decomposition,
soluble in 3-4 parts of water. d-Serine tastes sweeter than 1-serine (B. 38, 2942)
MONAMINOTHIOCARBOXYLIC ACIDS 541
Serine Methyl Ester, a syrup, loses alcohol spontaneously and passes into a
di-aci-piperazine (p. 391 ) :
oi which the 1-form [aJDas*** ~~ 67*46° appears to be identical with a decomposition
product of silk-fibroin.
Nitrous acid converts serine into gly eerie acid. PC16 changes serine ester into
ft-chloro-a-amino-propionic acid, which, on reduction, yields alanine ; 1-serine gives
d-alanine (p. 388).
^-Naphthaline Sulphoserine, m.p. 214°. Serine fi-Phenyl Cyanate, m.p. 169°.
fi-Amino-lactic Acid, a-Hydroxy-fi-amino-propionic Acid, Isoserine, H2NCHa-
CH(OH)COOH, m.p. 248° with decomposition, is prepared from fl-chlorolactic
acid (p. 368) or from glycidic acid (p. 539), and NH3 ; from o/J-diaminopro-
pionic acid, hydrochloride, and silver nitrite (B. 37, 336, 343, 1278) ; also by reduc-
tion of the addition product of acrylic acid and nitrous acid (C. 1903, II. 343) ;
Isoserine ethyl ester, m.p. 78° ; methyl ester, a syrup, passes easily into isoseryl
isoserine ester, and dipeptide. Isoserine ester hydrochloride yields glyceric ester
with sodium nitrite. Reduction produces /J-alanine (p. 393) (B. 37, 1277; 38,
4171).
a-Amir.o-p-hydroxy-butyric Acid, CH8CH(OH).CH(NHa)COOH, m.p. 230°
with decomposition, is obtained by reduction of the addition product of crotonic
acid and nitrous acid. HI and phosphorus yield a-aminobutyric acid (C. 1903,
II. 554).
a-Amino-y-hydroxy-butyric Acid, HOCH,.CH,CH(NH,)COOH, m.p. 207°
(indefinite), is obtained by the decomposition of /?-hydroxy-ethyl-phthalimido-
malonic mono-ester lactone, a product of ethylene bromide and sodium phtha-
limidomalonic ester (C. 1908, II. 683). The hydrobromide of the lactone
(formula, see below) is obtained by heating together hydrobromic acid and
y-Phenoxy-a-amino-butyric acid, m.p. 233° with decomposition. This substance
is prepared by acting with ammonia on phenoxybromobutyric acid, the result
of brominating and then decomposing phenoxyethylmalonic acid. The oily
lactone changes spontaneously into di-p-hydroxy ethyl diketopiperazine, m.p. 192°
(B. 40, 106) :
20CH2CHaCH/
JN x~i.«
a-Amino-y-hydroxy-valeric Acid, CH8CH(OH)CHaCH(NH2)COOH, m.p. 211°
with decomposition, is prepared from aldol, NH3, HCN, and HC1. Like thv
previous substance, it readily passes into the aminolactone, b.p.18 124°, which
spontaneously changes into the dipeptide anhydride, m.p. 224°. Reduction with
HI yields a-amino-n-valeric acid (B. 35, 3797).
8-Amino-y-hydroxy-valeric Acid, NH2CH2CH(OH)CH2CHaCOOH, is formed
from alkyl acetic acid dibromide (B. 32, 2682).
a-Amino-S-hydroxy-valeric Acid, HOCH2.CH2CH2CH(NHa)COOH, m.p. 224°
with decomposition, is prepared from phthalimidobromopropyl malonic ester,
BrCHaCHaCH2C(CO2R)2N(CO)aC,H4 (C. 1905, II. 398).
Monaminothiocarboxylic Acids.
a-Amino-B-thiolactic Acid, Cysteine, HSCHa.CH(NH2)COOH, is easily oxidized
by the air to the disulphide. Cystine, HOOC.CH(NH2)CH2S.SCHaCH(NHa)COOH.
decomposes at 258-261°. The laevo-rotatory form of this substance is obtained
from many proteins, especially from hair, horn, egg-shells. It is the chief
sulphur compound of the proteins. It occurs also in the crystallites of those
suffering from cystinuria (C. 1905, II. 1237). The action of nitrous and hydro-
chloric acids changes cystine into a-chlorodithiolactic acid, (SCHaCHCl.COOH)2,
which yields B-dithiopropionic acid, (SCH2CH2COOH)a, on reduction. Hydro-
bromic acid produces cysteinic acid, SO3H.CH2CH(NH2)COOH, which loses
CO2 and changes into taurine, SO8H.CH2CH2NHa (p. 326) (C. 1902, II. 1360).
Cysteine and cystine are closely connected with serine : (i) when jS-chloro-a-
amino-propionic acid (above) is heated with Ba(SH)2, it yields first cysteme and
then cystine ; (2) the syntheic benzoyl serine ester (p. 540), treated with P?S8
gives benzoyl cystetne ester, HSCH2CH(NHCOC2H6)COOC2H6, m.p. 158°, which
542 ORGANIC CHEMISTRY
on hydrolysis is changed to i-cysteine and i-cystine (A. 337, 222 ; B. 40, 3717).
l-Serine produces the natural laevo-rotatory cystine [a]D28= —224°. Cystine forms
crystals which dissolve with difficulty in water. Salts (C. 1905, II. 220) ; dimethyl
ester, is a syrup ; hydrochloride, m.p. 173°, with decomposition (C. 1905, II.
l23£'Thio-p-amino-propionic Acid, Isocysteine, NH2CH2CH(SH)COOH, hydro-
chloride, m.p. 141° with decomposition, is obtained from ^alanine (p. 393)
by gradual transformation of its ure'ide, hydrouracil (p. 444) — into bromohydro-
uracil, then into cyanohydrouracil, and decomposing the latter with hydrochloric
acid.
CO NH.CHa NH2CH2
NH— CO— CH.SCN COOH.CH.SH
Isocysteine is oxidized by iodine to Isocystine, [SCH(CH2NH2)COOH]2, m.p. 155°,
with decomposition ; and by hydrobromic acid into Isocysteine acid, HO3S.CH-
(CH2NH2)COOH (B. 38, 630).
a-Thio-y-amino-butyric Acid and y-Amino-a-butyro-sulphonic Acid, NH,CH2-
CH2CH(S03H)COOH (B. 41, 513)-
Diaminomonoearboxylic Acids.
Diaminopropionic Acid, CH2NH2.CHNH2.CO2H, is obtained from ajS-
dibromopropionic acid by means of aqueous ammonia ; also by the decompo-
sition of hippuryl asparaginic acid (p. 554). Optical resolution has been per-
formed by means of its salts with d-camphor sulphonic acid (Vol. II.) ; and through
the quinidine salts of dibenzoyl diaminopropionic acid (C. 1906, II. 1119 ; B.
39, 2950). The dextro-rotatory compound reacts with i molecule of HNO2
to form isoserine (p. 541), and with 2 molecules of HNO2 to produce 1-glyceric
acid. Diaminopropionic methyl ester is changed by heat into the ester of di-
aminopropionyl diaminopropionic ester, one of the dipeptides (B. 38, 4173).
ap-Diaminobutyric Acid, CH3CH(NH2).CH(NH2)COOH, is formed from
ajS-dibromocrotonic acid and ammonia, together with a hydroxyaminobutyric
acid (C. 1906, II. 764).
ay-Diaminobutyric Acid, NH2CH2CH2CH(NH2)COOH, is obtained from
phthalimido-ethyl-malonic ester by bromination, hydrolysis of the phthalimido-
a-bromobutyric acid formed, treatment with NH3, and final decomposition ;
dibenzoyl derivative, m.p. 201° (B. 34, 2900).
aS-Diaminovaleric Acid, NH2CH2CH2CH2CH(NH2)COOH, is synthetically
prepared from S-phthalimido-a-bromovaleric acid, and from the condensation
product of phthalimidopropyl bromide with sodium phthalimidomalonic ester
(C. 1903, II. 34). It is the optically inactive form of the dextro-rotatory Ornithine.
This body is produced, together with urea by the action of barium hydroxide
solution, on Arginine, a-Amino-S-guanidino-valeric Acid, NH2(NH)C.NHCH2-
CH2CH2CH(NH2)COOH, a substance found among the decomposition products
of many animal and vegetable proteins (B. 34, 3236 ; 38, 4187). Permanganate
converts arginine into y-guanidinobutyric acid (C. 1902, II. 200). It is prepared
synthetically from cyanamide, CN.NH2, and ornithine (B. 34, 454 ; C. 1902, I.
300). The dibenzoyl derivative of ornithine, Ornithurie Acid, m.p. 185°, occurs
in the urine of hens when fed with benzoic acid (B. 31, 3183).
CH2.CH(COOHK
a-Pyrrolidine Carboxylic Acid, Proline, I >NH, is the imine
CH2.CH2^-^
of 08 -diamino valeric acid. It results when casein, gelatin, and other proteins
are treated with hydrochloric acid. It can be synthetically prepared in
several ways, more particularly from a8-dibromovaleric acid and ammonia ;
and from 8-bromo-a-amino-valeric acid, the decomposition product of bromo-
propyl phthalimidomalonic ester (C. 1908, II. 680; B. 33, 1160; 34, 3071;
37, 3071 ; C. 1902, II. 284).
It is connected with the coca-alkaloids.
ae-Diaminocaproic Acid, NH2CH2CH2CH2CH2CH(NH2)COOH, is prepared
synthetically by the reduction of a-hydroximfdo-y-cyano-valeric acid by means
of sodium and alcohol. This product is the inactive form of the optically active
lysine, which is formed in the decomposition of casein and other proteins. Pan-
creatic decomposition converts lysine into pentamethylene diamine (cadaverine,
DIHYDROXYOLEFINE MONOCARBOXYLIC ACIDS 543
334) » and ornithine into tetramethylene diamine (putresceine, p. 333) (B. 32,
3542 ; C. 1902, I. 985). Permanganate oxidizes lysine into glutaric acid, together
with hydrocyanic and oxalic acids (B. 35, 3401).
Like the simple amino-acids, the hydroxyamino-, thioamino-, and
diamino-carboxylic acids are connected with one another and with the
mono-amino acids in so far that through their amides they go to form
protein-like bodies, such as di- and poly-peptides and dipeptide anhy-
drides (diazopiperazines, p. 391) . Therefore, in general, similar methods
of formation can be employed in both cases : Diglycl Cystine, [NH2-
CH2CONHCH(COOH)CH2S]2, is prepared from bischloracetyl cystine
and ammonia; Leucyl Proline f rom bromisocaproyl proline ; anhydride,
m.p. 126-129°. Protyl Alanine, from aS-dibromo-valeryl-alanine ; anhy-
XCH2.N— CO.CH3
dride, m.p. 171-121°. Prolvl Glycine Anhydride, CHa<; \ ,
\CH2.CH— CO.NH
m.p. 183°, is obtained by tryptic digestion of gelatin (comp. B. 37,
3071, 4575 ; 38, 4173 ; 39, 2060, etc.).
Dihydroxyolenne Monocarboxylic Acids.
The y-lactones of these bodies are the tetronic acid and mono-alkyl tetronic
acids. These substances can also be looked on as being the aci-forms of fi-Keto-y-
lactones. They are, therefore, considered under the heading of hydroxy-ketone-
carboxylic acids (below) according to the principle set down on p. 398.
ii, 12. Aldo-hydroxy-carboxylie Acids and Hydroxy-keto-carboxylie Acids.
Hydroxypyroracemic Acid, CH2OH.CO.COOH, or Formyl Hydroxy 'acetic
Acid, Tartronic Acid Semi- Aldehyde, CHO.CH(OH)COOH, is formed when
nitrocellulose (collodion cotton) is treated with sodium hydroxide solution.
Reduction converts it into /-glyceric acid ; hydrocyanic and hydrochloric acids
produce /- and some meso-tartaric acid (C. 1905, I. 1088). Formyl- or Hydroxy-
methyleng Hippuric Ester, OCH.CH(NHCOC,H6)CO2R, or HOCH : C(NHCOC6H6)-
COjR, m.p. 128° (comp. p. 540), is a derivative of formyl hydroxyacetic acid.
Tribromomethyl Ketol, CH2OH.CO.CBr,, decomposes at 174° (see Bromotetronic
Acid, p. 544).
The following substances are derived from the enol- or aci-iorm of
a-Hydroxyacetoacetic Acid, CH3COCH(OH)COOH, and y-Hydroxy-
acetoacetic Acid, HOCH2.COCH2COOH, both of which are unknown
in the simple form.
a-Thioacetoacetic Ester, S[CH(COCH3)CO2C2H5]2, keto-iorm, m.p. 76°, is
prepared by the action of sulphur chloride or thionyl chloride on acetoacetic ester.
The solid A^o-form is converted into the oily enol- or act-form by the influence
of solvents (alcohol, benzene), or a trace of alkali ; soda causes the re-production
of the keto-body (B. 39, 3255). Benzene-sulphone-thioacetoacetic Ester, C6H6-
SO2.SCH(COCH8)CO2C2H6, m.p. 55°, is prepared from a-chloracetoacetic ester
and benzene thiosulphonate (J. pr. Ch. [2] 70, 375).
a-Nitro-methyl-isoxazolone, ON:C(CH3).CH(NO2)CO, decomposes at 123°, is
formed when isonitroso-methyl-isoxazolone is oxidized by nitric acid (B. 28,
2093).
a-Amino-acetoacetic Acid, CH?CO.CH(NH2)COOC2H5, is obtained by the
reduction of isonitroso-aceto-acetic ester (p. 546) by zinc and sulphuric acid,
together with dimethyl pyrazine dicarboxylic ester (Vol. II.). Amino-acetoacetic
acid reacts with nitrous acid to form Diazo-acetoacetic Ester Anhydride,
Ncv /N
or CH,COC(CO2R)<J|, an oil, b.p.12 102-104°. Acids
and alkalis convert it into acetic and diazo-acetic acids (p. 402). When boiled
with water or superheated to above 110°, it breaks down into nitrogen and methyl
544
ORGANIC CHEMISTRY
malonic mono-ester (L. Wolff, A. 325, 129), a decomposition which may be
explained as follows (Schroeter) :
CH,COC(C02R)<J| > N1+CH,COC(C01R)< ->
CH3C(C02R)=CO .-^> CH3CH(C02R)C08H.
Ammonia or amines convert the diazo-anhydride into pyrro[ab]diazole ;
H.S produces thio[ab]diazole (Vol. II.). /3-Diketones react with it as with aromatic
diazo-bodies (Vol. II.), forming azo-compounds, such as hydrazones, which easily
condense further to pyrazoles.
a-Isonitramine Acetoacetic Acid; sodium salt, CH3COCNa(N2O2Na)COaCaH6
(pp. 397, 416).
Lactones of the y-Hydroxy-acetoacetic Acids (pp. 420, 543) are tetronic acid
and the alkyl tetronic acids. Substances of this class were obtained by Demarqay
from y-mono-bromo-substituted mono-alky! acetoacetic esters by alcoholic
potassium hydroxide, and were named by him tetrinic acid, pentinic acid, etc.
Michael recognized in tetrinic acid a keto-lactone (formula i). L. Wolff
examined the parent substance of these compounds and called it tetronic acid,
and derived Demarcay's acids from it under the names of a-methyl-, a-ethyl
tetronic acid, etc. (A. 291, 226). The keto- and enol-formulse (I. and II.) are
applicable to tetronic acid and a-methyl tetronic acid (tetrinic acid) :
CO.CH2V C(OH).CHav
I. | >0 II. || >0
CH3CH.CO/ CH,.C CO/
but Conrad and Gast favour the hydroxyl formula, through indirect evidence,
namely : that they prepared the lactone of y-hydroxy-dialkyl-acetoacetic acids
from dialkyl acetoacetic esters and y-bromo-dialkyl-acetoacetic ester, and
they showed that these true keto-lactones differ throughout in boiling-point and
chemical behaviour from tetronic acid and the a-alkyl tetronic acids.
C(OH)CH,v
Tetronic Acid, || }O (i) is prepared from synthetic tetronic ester,
CH— CO/
by hydrolysis, and elimination of CO2 (B. 36, 471) ; also by reduction by sodium
C(OH)CH2X
amalgam of a-Bronwtetronic acid, II >O (2) the decomposition product
CBr CO/
CO— CH2X
of ay-dibromacetoacetic ester. Dibromotetronic acid, \ j)O (3) is
CBr 2— CO/
obtained from bromotetronic acid and bromine. It slowly decomposes into
bromotetronic acid and tribromo-methyl-ketol (p. 543), with elimination of CO2.
C(OH)CH2V C(OH)CH2V CO— CHav
(i) I! >0 •< (2) || \0 > (3) | >0.
CH CO/ CBr O/ CBra-CO/
C(OH).CH2V
Tetrinic Acid, a-M ethyl Tetronic Acid, \\ >O, m.p. 189°, b.p.
CH3C-CO /
292°, with partial decomposition, results on heating y-bromo-methyl-aceto-
acetic ester or by treating it with alcoholic potassium hydroxide. Heated with
water to 200°, it breaks down into ethyl ketol (p. 341) and CO2, and when it
is boiled with barium hydroxide it yields glycollic acid and propionic acid,
Chromic acid oxidizes it to diacetyl and CO2 (A. 288, i).
Pentinic Acid, a-Ethyl Tetronic Acid, m.p. 128°. Hexinic Acid, a-Propyl
Tetronic Acid, m.p. 126°. Heptinic Acid, a-Isobtttyl Tetronic Acid, m.p. 150°.
It is the tertiary methinic group of the tetronic acid (formula i, above) and
the methylene group in the diketone formula (I., above) that react most actively
with other substances : iodine produces directly iodotetronic acid ; fuming
sulphuric gives rise to sulphotetronic acid. Nitrous acid gives oximidotetronic
acid, Oximido-ketobutyrolactone, (C4H2O3) : NOH, m.p. 136°, with decomposi-
tion, which on oxidation yields Nitrotetronic acid, (C4H2O3) : NOOH, m.p. 195°,
with decomposition ; this substance can also be prepared directly from tetronic
acid and nitric acid. Reduction results in the formation of aminotetronic acid,
ALDEHYDOKETONE CARBOXYLIC ACIDS 545
from which nitrous acid produces (i) Diazotetronic anhydride, m.p. 93°. It is
stable towards acids, but with alkalis generates nitrogen and forms (2) glycollo-
glycollic Acid, m.p. 100° (p. 367) :
/CH2.C(OH) /CH2.C— Ov ,CH2COOH
(i) 0< || - > (2) 0< || >N - > o(
NX).C(NH2) \CO.C— H^ XX).CH2OH
Tetronic acid reacts with diazobenzene salts to form diketobutyrolactone
phenylhydrazone, (C4H2O3) : NNHC6H8, which is isomerized by alkalis to salts
of benzene azotetronic acid. a-Methyl Tetronic acid is converted by rupture of
the ring into glycolyl pyroracemic acid phenylhydrazone,
XH2COOH
) : NNHC,H5
by diazobenzene salts.
Aldehydes and ketones unite very readily with two molecules of tetronic acid
to form alkylidene bis-tetronic acids, (C4H9Ot)tCRRlt substances from which
further condensation produces a series of interesting cyclic compounds (see Vol.
II.) (A. 312, 119; 322,351).
Ethoxyl Acetoacetic Ester, (C2H6O)CH2COCH2COOC2H6, or CH8.CO.CH-
(OC2H5).CO2C2H6, b.p.44 105°, is formed by reduction of ethoxyl chloraceto-
acetic ester, the condensation product of chloracetic ester and sodium (A. 269, 15).
y-M ethoxyl Dimethyl Acetoacetic Ester, (CH,O)CH2.CO.C(CH8)2CO2C2H6, m.p.
70°, b.p. 241°, is prepared from y-bromo-dimethyl-acetoacetic ester and sodium
methoxide in methyl alcohol (B. 30, 856).
y-Acetoxyla-Acetyl Butyric Ester, C2H8O.OCH2.CH2CH(COCH3)CO2CH8, b.p.,2
150-153°, is formed from glycol bromacetin (p. 230) and sodium acetoacetic
ester (C. 1904, II. 586).
a-HydroxylcBvulinic Acid, CH3CO.CH2CH(OH)CO2H, m.p. 103°, and /?-
Hydroxylavulinic Acid, CH3COCH(OH)CH2CO2H, an oil, are prepared from the
corresponding bromolaevulinic acids (A. 264, 259). Chloral acetone (p. 342)
may be considered as being the orthotrichloride of the first of these acids.
a-Amino-a-methyl-lfsvulinic Acid; the nitrile (formula, see below), b.p.17
108°, is formed from acetonyl acetone (p. 351) and ammonium cyanide. It
readily loses water and passes into a cyclic imine or pyrroline derivative (B. 40,
2886) :
CH2COCH8 CH8.C(CH8)(NH,)CN CH2—
_
CHjCOCH, CHjCOCHj, CH = qCH,,)/
Ketohydroxystearic Acid, CH3[CH2]5CH(OH)CH2CH2CO[CH2]7COOH, m.p.
84°, is obtained from ricinostearolic acid (p. 302). An isomeric ketohydroxy-
stearic acid, m.p. 64°, is obtained by oxidizing oleic acid with permanganate in
neutral solution (B. 36, 2657).
Hydroxy-oleflne Ketoearboxylie Acids include Hydroxymethylene Acetoacetic
Ester, HOCH:C(COCH3)CO2R, which can also be looked on as being the act-
form of formyl acetoacetic ester among the aldehydoketone carboxylic acids
(below).
13. ALDEHYDOKETONE CARBOXYLIC ACIDS
Glyoxyl Carboxylic Acid, CHO.CO.CO2H, is formed by the oxidation of
tartaric acid by chlorine in the presence of ferrous salts ; also from dihydroxy-
male'ic acid (q.v.) and ferric sulphate (C. 1902, I. 857, 978). Uric Acid may be
looked upon as the diure'ide of this half -aldehyde of mesoxalic acid. Di-isonitroso-
propionic Acid, HON:CH.C:N(OH).CO2H, is the dioxime of glyoxyl carboxylic
acid. It is obtained from dibromopyroracemic acid. It is known in two modi-
fications, the one m.p. 143°, the other m.p. 172° (B. 25, 909)- Furazan Carboxylic
Acid, o<Ni9>C°2H> m.p. I07°, is the anhydride of this dioxime. It results
from the oxidation of furazan propionic acid with KMnO4. Sodium hydroxide
causes it to rearrange itself into cyanoximido-acetic acid (A. 260, 79 ; B. 24,
1167). Osazone of glyoxyl carboxylic acid, CH(NNHC6H5)C(NNHC6H6)COOH,
m.p. 223°.
VOL. I. 2 N
546 ORGANIC CHEMISTRY
Glyoxyl Propionic Acid, HCO.CO.CHaCH2CO?H, results, together with
diacetyl, when £S-dibromol£evulinic acid is boiled with water. It forms a yellow
varnish ' It passes into succinic acid upon oxidation. Its oxime is y§-dioximido-
valeric acid, HC(:NOH).C(:NOH).CHa.CHa.COaH, m.p. 136°. Concentrated
sulphuric acid changes it into the anhydride, Furazan Propionic Acid,
O<N:?-CH>CH«CO«H, m.p. 86°. Sodium hydroxide converts this acid into
cyanoximidobutyric acid (p. 568), whilst with potassium permanganate it yields
furazan carboxylic acid. In the form of a keto-aldehyde (see pp. 346, 349),
glyoxyl propionic acid condenses with ammonia and formaldehyde to a glyoxaline
^N — CH
propionic acid, CH^ || * which is also produced from histidine,
xNH.CCHaCH2C02H
one of the protein decomposition bodies (C. 1905, II. 830 ; 1908, II. 606).
Gloxyl Isobutyric Acid, CHO.CO.C(CH8)aCOOH, m.p. 138°, is obtained from the
isomeric Dihydroxyacetyl Dimethyl Acetic Acid Lactone, (HO)CH.CO.C(CH8)aCOO,
m.p. 1 68°, by solution in soda and subsequent precipitation by hydrochloric acid.
The lactone was obtained on treating y-methoxy-dimethyl-acetoacetic ester
with bromine, and then decomposing the monobromosubstitution product with
water (B. 30, 856).
Derivatives of an aldehydo-keto-carboxylic acid, CHO.CHaCO.COaH (or
an unsaturated hydroxy-aldehydic acid, CHO.CH:C(OH)COaH), are probably
exemplified by muco-hydroxy-chloric acid and muco-hydroxy-bromic acid (p. 402)
(Am. 9, 148 ; 160).
Formyl Acetoacetic Acid, CHO.CH(COCH,)COOH, and in its desmotropic
enol-forms, H9CH:C(COCH8)COOH, and CH8C(OH):C(CHO)COaH, is the
hypothetical acid from which may, perhaps, be derived
Hydroxymethylene Acetoacetic Ester, HOCH=C<^J^|H», b.p.81 95°, which
is formed by the action of water on Ethoxymcthylene Acetoacetic Ester,
6, b.p.16 150°. The substances are also obtained from
orthoformic ester and acetoacetic ester by heating them with acetic anhydride
(B. 26, 2730). Hydroxymethylene acetoacetic ester is a strong acid (see Hydroxy-
methylene Acetyl Acetone, p. 536) ; it is readily soluble in alkali acetates, but
is insoluble in water ; copper salt, m.p. 156°. Ethoxymethylene acetoacetic
ester is converted by ammonia into Aminomethylene Acetoacetic Ester (C6H8O8)-
=CH.NHa, m.p. 55°, and combines with acetoacetic ester to form Methenyl
Bis-acetoacetic Ester, (C6H8O8):CH(C6H9O8), m.p. 96°. The latter is converted
by ammonia into lutidine dicarboxylic ester (Vol. II.) ; and by sodium ethoxide
into m-hydroxyuvitic acid (L. Claisen, A. 297, 14). When alkoxymethylene
acetoacetic acid is melted with sodium acetoacetic ester, two dyes of undeter-
mined structure are formed — xanthophanic acid and glaucophanic acid (B. 39, 2071).
14. DIKETOCARBOXYLIC ACIDS
Paraffin DIketocarboxylic Acids.
a.^-Diketobutyric Acid, afi-Dioxybutyric Acid, Acetyl Glyoxylic Acid, CH8CO.-
CO.COOH. The acid is unknown in the free state, but the ester is obtained
when acetoacetic ester is acted on by NaO8, in acetic anhydride and ether
solution. The esters are orange-yellow, mobile liquids (comp. a-Diketones and
a-Triketones, p. 348), which combine with water to form colourless crystalline
hydrates: methyl ester, b.p.is 65-68°, +HaO, m.p. 80°; ethyl ester, b.p.18 70°,
+iH2O, m.p. 148°; isobutyl ester, b.p.18 96-100°, +£HaO, m.p. 115-120°.
Isonitroso-acetoacetic Estor, CH3COC(NOH)CO2R, is an intermediate product
in the formation of the above esters. The ethyl ester, m.p. 56°, b.p.15 155°,
can be isolated by treating acetoacetic ester in acetic acid solution with ice-cold
sodium nitrite solution ; the action of NO. converts it into the diketobutyric
ester (C. 1905. 1. 1591 ; n. 34) :
CH8CO HONO CH8CO CO, CH.CO
ROCO.CH, ROCO.C=NOH " ROCO.C=O
DJKETOCARBOXYLIC ACIDS 547
Isonitroso-acetoacetic ester is also formed from acetyl malonic ester (p. 564)
and nitrous acid. One molecule of hydroxylamine produces a/3-Di-isonitroso-
butyric Ester, CH3C(NOH).C(NOH)COaC2H6, m.p. 161°, which is changed by
hydrochloric acid into isonitroso-methyl-isoxazolone (i), m.p. 159°, one of the
lactazones (see p. 416), whilst nitric acid causes the formation of a peroxide (2)
m.p. 92° (B. 28, 2683 ; 38, 926) :
CH3C.C(NOH).CO CH3C - C.CO2H
(i) H I (2) I! ||
N - O N.O.O.N
p-Phenylhydrazone Acetyl Glyoxyl Ester, CH3C(NNHCaH6).CO.COaC2H8, m.p.
103°, is formed from diketobutyric ester and one molecule of phenylhydrazine
in the cold.
a-Phenylhydrazone Acetyl Glyoxyl Ester, CH3CO.C(NNHC6H5)CO8C2H8, m.p.
154°, is prepared from sodium acetoacetic ester and diazo-benzene salts ; with
phenylhydrazine it forms an Osazone, m.p. 209° (A. 247, 205 ; C. 1904, II. 588).
py-Diketovaleric Acid, fiy-Dioxovaleric Acid, CH3CO.CO.CH2CO2H, is
unknown ; but its derivative,
p-Isonitrosolezvulinic Acid, CH3CO.C(NOH)CHaCO2H. m.p. 119* with
decomposition, is formed from acetosuccinic ester (p. 568). When fused, it
loses CO2 and changes into isonitroso-methyl-ethyl-ketone (p. 354).
a-Diketoearboxylic Acids include stearoxylic acid, and behenoxylic acids, etc.,
which have already been referred to (p. 304). 9, iz-Diketostearic Acid, m.p. 96°,
is obtained from ricinostearolic acid (p. 302) C. 1907, I. 916).
j8-Diketocarboxylic Acids.
Acetyl Pyroracemic Ester, Acetone Oxalic Ester, ay-Diketo- or ay-Dioxo-valeric
Ester, CH3CO.CH2CO.COaCaHB, is formed from one molecule of acetone, one
molecule of oxalic ester, and sodium ethoxide solution (C. 1908, 1, 1379). Ferric
chloride produces a dark red colour. The free acid liberated from the ester
condenses to sym.-hydroxytoluic acid, CO2H[i]CeH3[3,5](OH)CH3 (B. 22,
3271). Acetone oxalic ester and phenylhydrazine form Phenyl Pyrazole Car-
boxylic Ester, m.p. 133° (A. 278, 278). With chloral it behaves as an a-hydroxy acid
and there results Acetyl Pyroracemic Chloralide, C
m.p. 137° (B. 31, i3°5)-
Besides acetone, other ketones, such as ethyl methyl ketone, isobutyryl,
and butyryl ketone, react with oxalic ester and sodium alcoholate to form Pro-
piony I Pyroracemic Ester, CH3CH2CO.CH2COCO2C2H5 (?), b.p.0.6 73-78°; acid,
m.p. 83 (B. 39, 1333), Isobutyryl Pyroracemic Ester, (CH3)2CHCO.CH2COCO2C2H6,
and Butyryl Pyroracemic Ester, CH»CHjCHaCOCH2COCO2C2H5 (C. 1902, II.
189 ; 1903, I. 138) respectively.
Diacyl Acetic Esters.
The hydrogen in acetoacetic ester can not only be replaced by alkyls, as
abundantly shown above, but also by acid radicles (comp. p. 419), by acting with
icid chlorides on the sodium compound suspended in ether.
a-Acetyl Acetoacetic Ester, Diacetyl Acetoacetic Ester, (CH3CO)2CHCO2CaHt,
D.p.60 123°, is prepared by the action of acetyl chloride as indicated above ; by the
iransformation of the isomeric /?-acetoxycro tonic ester by means of K2CO3,
>r by heat (p. 418) ; by the action of alcohol on the reaction product of A1C13
md acetyl chloride, (CH3CO)2CH.CClaOAlCla (p. 350) (Gustavson, B. 21, R. 252).
The anilide, (CH8CO)2CH.CONHC,H5, m.p. 119°, results from the union of
liacetyl methane with phenyl isocyanate, and a trace of alkali (B. 37, 4627 :
>8, 22). The diacetoacetic ester, like acetoacetic ester itself, forms metallic
alts. Water at ordinary temperatures slowly converts it into acetic acid and
.cetoacetic ester: sodium ethoxide causes the displacement of the acetyl
'roup with the formation of acetic ester and sodium acetoacetic ester. Pyridine
nd acetyl chloride form an O-acetate, CH3C(OCOCH3):C(COCH3)CO2C2HB,
>.p.10 143° (B. 33, 1245). Cyanacetyl Acetone, see Acetyl Acetone (p. 351).
Methyl Diacetoacetic Ester and Ethyl Diacetoacetic Ester are volatile only under
educed pressure.
Diacyl acetoacetic ester containing two different acid radicles can be decom-
posed in three ways (comp. pp. 217, 351, 4I5)- When such an ester is treated
water at 148-150°, there are formed diacyl methane, CO,, and alcohol ;
548 ORGANIC CHEMISTRY
ammonia or fixed alkali in the cold produces mono-acyl-acetic ester and acetic
acid ; heated with hydrochloric at 130-140° it breaks down into alkyl methyl
ketone, COa> acetic acid, and alcohol (C. 1903. !• 225) :
RCQ >. RCOCH2COCH,+COa+CaH6OH
\CHC02C2H8 >- RCOCH2C02C2H6+CH3COOH
CH8C(X — ^ RCOCH3+COa+C2H6OH+CH3C02H
lodo-alkyls react with sodium diacyl acetic ester and form acyl alkyl acetic
ester by replacement of the acetyl group (C. 1904, II. 25).
Propionyl Acetoacetic Ester, C2H6COCH(COCH3)CO2C2H6, b.p.ao 111°; copper
salt, m.p. 89°. n-Butyryl Acetoacetic Methyl Ester, b.p.14 105°. Isobutyryl
Acetoacetic Ester, b.p.15 114°. Caproyl Acetoacetic Ester, b.p.10 136°. Butyryl
Isobutyryl Acetic Ester, CH8CH2CH2COCH[COCH(CH3)a]CO2C2H5, b.p.18 125°.
BB-Diacetopropionic Ester, (CH3CO)2CHCH2CO2CaH6, b.p.24 147°, pp-Diaceto-
isobutyric Ester, (CH3CO)2CHCH(CH3)CO2C2H3l b.p.33 150°, yy-Diacetobutyric
Methyl Ester, (CH3CO)2CHCHaCH2CO2CH3, b.p.24 161°, are formed from sodium
acetyl acetone and chloracetic ester, a-bromopropionic ester, and j3-bromo-
propionic ester, respectively. Sodium alcoholate decomposes diacetopropionic
ester into acetic ester and laevulinic ester ; sodium alcoholate and iodomethane
break it down into acetic ester and jS-methyl laevulinic ester. Diacetobutyric
ester undergoes similar changes (C. 1902, II. 345).
y- Acetyl Acetoacetic Ester, Triacetic Acid is prepared in the form of its
lactone, CH3C:CHCO.CH2COO, by heating dehydracetic acid (q.v.) with sulphuric
acid (B. 34, R. 857). When heated with acetic anhydride and sodium acetate it
is then reconverted into dehydracetic acid (B. 37, 338 ; C. 1905, I. 348 ; 1906,
II. 1044).
y- Acetyl Dimethyl Acetoacetic Methyl Ester, a-Dimethyl Triacetic Ester, CH8-
CO.CH2.COC(JH3)2COaCH3, is formed, together with isobutyric ester, from
dimethyl acetoacetic methyl ester and sodium at 115-125° (B. 31, 1339).
y- Acetyl a-Dimethyl Acetoacetic Ester is similarly formed from diethyl aceto-
acetic ester and sodium ethoxide (B. 33, 2683).
y-Diketocarboxylic Acids.
A cetony I Acetoacetic Ester, afi-Diacetopropionic Ester, CH3COCHa.CH(COCH,)-
COaC2H5, is formed from chloracetone and sodium acetoacetic ester. Fuming
hydrochloric acid turns it into pyrotritaric ester (B. 17, 2759).
When heated with water to 160° the ester yields acetonyl acetone (p. 351).
Acetonyl Lavulinic Acid, CH3COCHaCH2COCHa.CHaCO2H, m.p. 75°, is»
formed from furfuracetone (Vol. II.) when heated with hydrochloric acid (B. 32,
1176).
Unsaturated Diketoearboxylie Acids, p-Mesityl Oxide Oxalic Acid, (CH3)aC;CH.-
CO.CH2.CO.COaH, m.p. 166° with decomposition. Potassium hydroxide
liberates it from either its ethyl ether, m.p. 59°, b.p.u 143°, or its methyl
ether, m.p. 67°. On allowing sodium in ether to act on molecular quantities
of mesityl oxide and oxalic ester, then acidifying with dilute sulphuric acid and
distilling, a mixture of a- and j8 -mesityl oxide oxalic esters results. It can be
separated by means of a sodium carbonate solution, in which the a-ether alone
is soluble. Ferric chloride turns this a blood red.
a- or zci-Mesityl Oxide Oxalic Ethyl Ester, (CH3)2C:CHC(OH):CHCOaCaH6,
m.p. 21°, gives a blood-red coloration with ferric chloride. Potassium hydroxide
solution liberates the corresponding acid, m.p. 92 (A. 291, HI, 137).
15. MONOHYDROXY-DICARBOXYLIC ACIDS
A. MONOHYDROXY-PARAFFIN DICARBOXYLIC ACIDS, CwH2n-i(OH)(CO2H)2.
Numerous saturated monocarboxylic acids are known : thus,
the hydroxymalonic acid group corresponds with the malonic acid
group, hydroxysuccinic acid group with the ethyl succinic acid group,
hydroxyglutaric acid group with the glutaric acid group, etc.
HYDROXYMALONIC ACID GROUP 549
It may be mentioned here that there are many representatives of
these acids in which the hydroxyl group occupied the y-position with
reference to the carboxyl group, and these acids, when separated from
their salts, readily part with water and become lactones. In general,
the alcoholic hydroxyl group is introduced into the dibasic acids, just
as it is done in the case of the monobasic acids. The reaction leading
to the alkyl paraconic acids (p. 557) is worthy of mention. It is a
condensation reaction between aldehydes and succinic acid or mono-
alkylic succinic acids (p. 493).
HYDROXYMALONIC ACID GROUP
CO TT
Tartronic Acid, CH(OH)<^2g, Hydroxymalonic Acid [Pro-
panol diacid], m.p. 184° with decomposition, is produced : (i) From
glycerol by oxidation with potassium permanganate ; (2) from chloro-
and bromo-malonic acid by the action of silver oxide or by hydro-
lysis of their esters with alkalis ; (3) from trichlorolactic acid when the
latter is digested with alkalis (B. 18, 754, 2852) ; (4) from dibromo-
pyroracemic acid when digested with barium hydroxide solution ;
(5) from mesoxalic acid (p. 562) by the action of sodium amalgam.
(6) Nucleus synthesis : from glyoxylic acid (p. 400) by the action of
HNC and hydrochloric acid, (7) by the spontaneous decomposition
of nitrotartaric acid and of dihydroxytartaric acid. (8) It can be con-
veniently prepared from tartaric acid by allowing it to remain in con-
tact with nitric acid and P205 (A. 343, 154).
Its formation from nitrotartaric acid, described in 1854 by Des-
saignes, has given it the name tartronic acid.
Tartronic acid is easily soluble in water, alcohol, and ether, and
crystallizes in large prisms. On melting it is decomposed into carbon
dioxide and polygly collide, (C2H2O2)# (p. 367) (B. 18, 756).
The calcium salt, C3H2O5Ca, and barium salt, C3H2O5Ba-}-2H2O,
dissolve with difficulty in water, and are obtained as crystalline pre-
cipitates.
Ethyl Ester, CH(OH)(CO2C2H6)2, b.p. 222-225° (B. 18, 2853) ; Ethoxyl Malonic
Acid, C2H6O.CH(CO2H)2, m.p. 124° ; ethyl ester is formed from ethoxyl acetic
ester (q.v.) ; acetate, CH3CO.OCH(CO2C2H5)2, b.p.62 158-163° (B. 24, 2997).
Chloral- and bromal-cyanhydrins (p. 379) and trichlorolactic acid (p. 368)
may be looked on as being derivatives of tartronic acid. See also Chloro- and
Bromo-malonic ester (p. 489).
Nitromalonic Ester, NO2.CH(CO2C2H6), b.p.to 127°, and nitromalonamide,
NO2CH(CONH,),, are prepared from malonic acid and malonamide, respectively,
by nitric acid (C. 1901, I. 1196; 1902, I. 1198; 1904, II. 1109). Nitromalonic
Dimethylamide, NO2.CH(CO.NHCH8)2, m.p. 156° (B. 28, R. 912). Fulminuric
Acid is a nitromalonic acid derivative (p. 250).
Methyl Nitromalonic Ester, NO2C(CH8)(CO2C2H5)2, is formed from the
ammonium salt of nitromalonic ester and iodomethane. The higher alkyl
nitromalonic esters are obtained by nitrating alkyl malonic esters. Sodium
alcoholate converts them into nitro-fatty acid esters (C. 1904, II. 1600).
Aminomalonic Acid, NH2CH(CO2H)8, m.p. 109 with decomposition, is
formed by the reduction of isonitrosomalonic acid (p. 563) ; from chloromalonic
acid and ammonia (B. 35, 2550) ; by alkaline decomposition of uramil (p. 578)
550 ORGANIC CHEMISTRY
(A. 333, 77). It forms brilliant prisms. When warmed in aqueous solution
it is decomposed into CO, and glycine (p. 385)- Methyl Ester Hydrochloride,
m.p. 159° with decomposition, and Ethyl Ester Hydrochloride, m.p. 162° with decom-
position, are obtained from their acids, and from the isonitrosomalonic esters
by reduction. Ammonia produces from them Aminomalonamide, m.p. 192°
with decomposition (B. 39, 514). This body is also prepared from chloromalonic
ester and alcoholic ammonia at 130°, together with some Iminomalonamide,
NH[CH(CONH2)2]a (B. 15, 607). Aminomalononitrile, NHa.CH(CN)2, m.p. 184°,
is a product of polymerization of hydrocyanic acid (p. 241 ) (B.35, 1083). Anilino-
malonic Acid, C6H5NH.CH(CO2H)2,m.p. 121° (C. 1897, H. 568 ; 1898, I. 829).
The esters of this acid are condensed to indoxylic ester (see Indigo, Vol. II.).
Phthalimidomalonic Ester, C,H4(CO)2N.CH(COaCaH5)a, m.p. 74°, is formed
from bromomalonic ester and potassium phthalimide (C. I9<>3> II. 33)-
Alkyl Tartronic Acids. — Methyl Tartronic Acid, Isomalic Acid, a-Hydroxyiso-
succinic acid, CH3C(OH)(COaH)2, is obtained (i) by the action of silver oxide
on bromisosuccinic acid ; (2) when hydrocyanic acid acts on pyroracemic
acid ; Pyroracemic ester and hydrocyanic acid produce the nitrile ester,
CHSC(OH)(CN)CO2C2H8, m.p.lfl 105°, which is converted on hydrolysis to iso-
malic acid (C. 1899, I. 1206; B. 39, 1858); (3) Diacetyl cyanide (p. 409), the
acetate of Methyl T artrodinitrile , CH3C(OCOCHa)(CN)2, is hydrolyzed by fuming
hydrochloric acid to methyl tartronic acid (B. 26, R. 7 ; 27, R. 510). The acid
breaks down into CO2 and lactic acid when it is heated to 140°.
Ethyl Tartronic Acid, C2H6C(OH)(CO2H)2, m.p. 98°, is formed (i) on boiling
ethyl chloromalonic ester with barium hydroxide solution (p. 491); (2) from
dipropionyl cyanide (p. 409) ; (3) by the action of ethyl iodide on sodium
acetartronic ester (B. 24, 2999). When heated above its melting point it breaks
down into COa and a-hydroxybutyric acid. Propyl Tartronic Acid, CH3CH2CH2.-
C(OH)(COaH)a+HaO, m.p. 52-56°, and Isopropyl Tartronic Acid, decomposes
at 149°, are formed by the hydrolysis of dibutyryl and diisobutyryl dicyanide
(p. 409) (B. 28, R. 295).
a-Aminoisosuccinic Acid, CH,.C(NHI)(COOH)1> results when pyroracemic acid
is acted on with HNC and alcoholic ammonia (B. 20, R. 507).
fi-Hydroxyisosuccinic Acid, CHaOH.CH(COaH)8, a syrup, is produced by
hydrolysis of the reaction product of chloromethyl ether (p. 207) and sodium
malonic ester. It decomposes at 113° into HaO, CO2, and acrylic acid (C. 1904,
II. 641); ethyl ^^r,C2H6OCH2.CH(COsH)a, has been obtained from methylene
malonic ester (p. 508) by the action of alcoholic potassium hydroxide (B. 23, R. 194).
y-Hydroxyalkyl Malonic Acids. — The following y-hydroxymalonic acids are
only known in the form of alkali or alkali earth salts. These are produced
when the corresponding y-lactone carboxylic acids are treated with alkali
hydroxides or the hydroxides of the alkali earths. The y-lactonic acids can
easily be obtained from these salts ; these salts are produced by treatment with
carbonates.
f»TT f*TT f"*T-T/~*/"^ *tT
Butyrolactone a-Carboxylic Acid, I *| * , is prepared from brom-
ethyl malonic acid, BrCHaCHa.CH(COaH)a, m.p. 117°. This is the hydro-
bromide addition product of vinaconic acid, thetrimethylene-i,i-dicarboxylic acid,
when it is heated with water; also on digesting the latter with dilute sulphuric
acid (A. 227, 31). Heated to 120°, butyrolactone carboxylic acid breaks down
into COa and butyrolactone (p. 373). The ethyl ester, b.p.S5 175°, is formed by
the combination of ethylene oxide and sodium malonic ester, whereby hydroxy-
ethyl malonic ester is produced, which immediately loses alcohol to form a lactone.
Ammonia converts the lactone ester into B-Hydroxy ethyl Malonamide, HOCH2CH2-
CH(CONH2)2, m.p. 150° (B. 34, 1976). The phenyl ether of Hydroxyethyl Tartronic
Acid, C,H6O.CH,.CH,.CH(COOH)a, m.p. 142° (B. 29,R. 286).
H»CH(CH8)COaH
a-Methyl Butyrolactone a-Carboxylic Acid,
-CO
results when bromethyl isosuccinic ester, the reaction product of ethylene bromide
and sodium isosuccinic ester, is treated with barium hydroxide solution and then
acidified [A. 294, 89).
HYDROXYSUCCINIC ACID GROUP 551
a-Carbovalerolactonic Acid, y- Methyl Butyrolactone a-Carboxylic Acid
GH8CHCHaCHC02H
| | , results when allyl malonic acid is acted on with HBr.
It breaks down at 200° into CO2 and y-valerolactone (p. 374).
HYDROXYSUCCINIC ACID GROUP
Malic Acid, Hydroxyethylene Succinic Acid (Acidum malicum],
HO.*CHCOaH
[Butanol diacid], I , m.p. 100°. Since malic acid contains
CH2CO2H
an asymmetric carbon atom, it can occur in three modifications t
(i) a dextro-rotatory form, (2) a Isevo-rotatory form, and (3) an
inactive [d-fl] variety. This is a compound of equal molecules of
the dextro- and laevo-rotatory modifications.
The laevo-variety occurs free or in the form of salts in many plant
juices, hence it is frequently spoken of as ordinary malic acid. It is
found free in unripe apples, in grapes, and in gooseberries, also in
mountain ash berries (Sorbus aucuparia), in Berberis vulgaris, and
in the sea buckthorn (or sallow thorn), Hippophae rhamnoides
(B. 32, 3351). It is obtained from the last-named fruits by means of
the calcium salts (A. 38, 257 ; B. 3, 966). Calcium hydrogen malate
exists in tobacco leaves ; potassium hydrogen malate in the leaves
and stalks of rhubarb (C. 1902, I. 1399). On malic acid obtained
from the Crassulacece, see B. 31, 1432.
Historical. — Ordinary malic acid was discovered in 1785 by Scheele in unripe
gooseberries. Liebig ascertained its composition in 1832. Pasteur, in 1852,
obtained inactive malic acid from inactive aspartic acid, and Kekutt (1861) made
it from bromosuccinic acid. The dextro-acid was first obtained by Brewer in
the reduction of dextro-tartaric acid.
Formation of Optically Inactive or (d+1] Malic Acid, m.p. 130° (B. 29, 1698) :
1. From the mono-ammonium salt of laevo- and dextro-malic acid.
2. By heating fumaric acid to 150-200° with water.
3. When fumaric or maleic acid is heated with sodium hydroxide to 100°
(B. 18, 2713).
4. By treating monobromosuccinic acid with silver oxide and water with
water alone, with dilute hydrochloric acid, or with dilute sodium hydroxide at
100° (B. 24, R. 970).
5. By the action of N2OS on inactive aspartic acid.
6. By the reduction of racemic acid with hydriodic acid.
7. When oxalacetic ester is reduced with sodium amalgam in acid solution
(B. 24, 3417; 25,2448).
8. By the action of potassium hydroxide on the transposition-product of
KNC and j8-dichloropropionic ester.
9. By saponifying the esters of chlorethane tricarboxylic acid.
10. When potassium hydroxide acts on y-trichloro-jS-hydroxybutyric acid,
CC13CH (OH )CHaCOaH,' the reaction-product of glacial acetic acid or pyridine with
chloral and malonic acid (B. 25, 794 ; 38, 2733).
The identity of the acids from i to 6 has been proved by means of the well-
crystallized mono-ammonium salt, C4H,O6NH4+HaO, of the inactive acid
(B. 18, 1949, 2170).
Formation of the Icevo- and dextro- forms : Both acids can be
produced by resolution of the inactive malic acid by cinchonine
(B. 13, 351 ; 18, R. 537). The dextro-acid has also been obtained
55*
ORGANIC CHEMISTRY
by the reduction of ordinary or dextro-tartaric acid with hydriodic
acid, and by the action of nitrous acid on dextro-aspartic acid,
whereas 1-asparagine and 1-aspartic acid yield ordinary or 1-malic
acid (B. 28, 2772). The two optically active malic acids can be
converted into each other by treating chlorosuccinic acids, obtained
from them by the action of PC15, with moist silver oxide (Walden, B.
29, 133).
Properties. — Malic acid forms deliquescent crystals, which dissolve
readily in alcohol, slightly in ether.
Reactions. — (i) When heated to 100° anhydro-acids are formed
(B. 32, 2706) ; at 140-150° mainly fumaric acid results ; when rapidly
heated to 180° it decomposes into water, fumaric acid, and male'ic
anhydride (pp. 510, 511). Prolonged boiling with aqueous sodium
hydroxide converts malic acid partially into fumaric acid (B. 33, 1452).
(2) Oxidation with permanganate or hydrogen peroxide in presence of
ferrous salts produces oxaloacetic acid (p. 564). (3) Reduction gives
rise to succinic acid. It results from the fermentation of the calcium
salt by yeast, of the free acid by Bacillus aerogenes (B. 32, 1915), and
when the acid is heated to 130° with hydriodic acid (p. 492). (4) Heating
with hydrobromic acid produces bromosuccinic acid; 1-malic acid
and PC16 at ordinary temperatures yield d-chlorosuccinic acid, which,
with moist silver oxide changes into d-malic acid (pp. 499, 500). ' (5)
When heated alone or with sulphuric acid or zinc chloride, it is con-
verted into coumalic acid (p. 561). (6) On being heated with phenol
and sulphuric acid, coumarin results ; it is possible that the half alde-
hyde of malonic acid CHO.CH2.CO2H is first formed, with which the
phenol then condenses (B. 27, 1646).
Salt and esters of i-malic acid : Mono-ammonium Malate, C4H6O6NH4-f-H2O
(B. 18, 1949, 2170). Resolution into the optical components (B. 31, 528).
i-Malic Diethyl Ester, C2H3(OH)(CO2C2H6)2, b.p. 255° (B. 25, 2448).
Salts of the lavo-acid, malates : Mono-ammonium salt, C4H6O6(NH4), when
exposed to a temperature of 160-200°, becomes converted into fumarimide
(A. 239, 159 note).
Neutral Calcium Malate, C4H4O6Ca+H2O, separates as a crystalline powder
on boiling. Acid salt, (C4H6O6)2Ca+6H2O, forms large crystals which are not
very soluble in cold water, but are more soluble in hot (B. 19, R. 679).
1-Malic Ethers and Esters : The dialkyl esters are prepared from malic acid,
alcohols, and hydrochloric acid. They can be distilled unchanged (Z. phys. Ch. 16,
494), but when slowly heated pass into fumaric esters (B. 18, 1952). Reaction
with PC15 and PBrB in chloroform changes them into d-chloro- and d-bromo-
succinic esters (p. 499). Attempts to prepare malic esters by means of the silver
salt of the acid result in the partial substitution of the hydroxyl hydrogen by
the alcoholic radical (C. 1899, I. 779).
The optical rotatory power of many of these esters has been determined ; they
are laevo-rotatory (B. 28, R. 725 ; 29, R. 164, C. 1897, 1. 88) :
1-Malic Methyl Ester b.p.ia 122°
1-Malic Ethyl Ester „ 129°
1-Malic n-Propyl Ester „ 150°
1-Malic n-Butyl Ester „ 170°
[a]D = — 6.88, [M]D = — 11-15
[a]D = — 10.64, [M]D = — 20- 22
[a]D = — II. 60, [M]D =• — 25-29
[a]D =—10.72, [M]D =—26-38
Triethyl Ester, C2H6O.C2H3(CO2C2H5)2, b.p.15 119° (B. 13, 1394).
Acetyl Malic Acid, CH3CO.OC2H3(CO2H)2, m.p. 132°.
Acetyl Malic Dimethyl Ester, CH3CO.OC2H3(CO2CH3)2, when carefully dis-
tilled at the ordinary temperature, yields fumaric dimethyl ester. Acetyl
Malic Anhydride, CH8CO..OCaH8(C,Oa), m.p. 54°, b.p.14 161°, decomposes when
AMINOSUCCINIC ACIDS 553
distilled at the ordinary temperature into malei'c anhydride and acetic acid
(A. 254, 166).
Acetyl-1-malic Methyl Ester, b.p.12i32°; [a]D= — 22*86, [M]D = — 46-64.
Acetyl-1-malic Ethyl Ester, b.p.l2 141° ; [a]D=— 22-60, [M]D=— 52-43.
Propionyl-1-malic Methyl Ester, b.p.12 142° ; [a]D= — 23-08, [M]D= — 50-31.
On the homologous series ofacyl l-malic ethyl esters and their molecular rotations
(Z. phys. Ch. 36, 129).
Nitromalic Ester, NO2.OCH(CO2R)CH2CO2R ; methyl ester, m.p. 25° [off
—33-01°, and ethyl ester, b.p. 148-151° [aft3-^!^0, are prepared from the
l-malic esters and nitrosulphuric acid (B. 35, 4363).
Amides of the malic acids, a- and fi-Malic Mono-amides, NH.CO.CH(OH)CH«-
COOH and HOOC.CH(OH)CH2.CONH2, and their esters are formed from the
malic esters and alcoholic ammonia ; from malonamide by partial hydrolysis ; also,
from bromosuccinic acid and ammonia, a reaction which may result in this amide,
partially or wholly in place of the expected aspartic acid (B. 41, 841). Malamide,
HO.C2H3(CONH2)2, is prepared fro'm the monoamidomalic ester and from the
malic ester by the action of ammonia (C. 1900, II. 1009).
Thiomalic Acid, HOOC.CH2CH(SH)COOH, m.p. 150°, is formed by the
action of ammonia on Xanthosuccinic Acid, HOOC.CH2CH(SCSOC2H6)COOH,
m.p. 149°, which in turn is prepared from bromosuccinic acid and potassium
xanthoganate (A. 339, 369 ; B. 38, 2687).
Sulphosuccinic Acid. SO3H.C2H3(COOH)2, is prepared from succinic acid
and S0a (A. 175,20).
AMINOSUCCINIC ACIDS
Aspartic acid bears the same relation to malic and succinic acids as glycocoll
bears to glycollic acid and acetic acid ; hence, it may be called aminosuccinic
acid :
NH2.CH2C02H HO.CH2C02H CH8.CO2H
Glycocoll. Glycollic Acid. Acetic Acid.
NHa.CHCOjH HO.CHCO2H CHa.CO2H
CH2C02H CH2C92H CH2.CO2H
Aminosuccinic Acid. Malic Acid. Succinic Acid.
Aminosuccinic acid contains an asymmetric carbon atom, so that
like malic acid, it appears in three modifications. The 1-aminosuccinic
acid or Isevo-aspartic acid is the most important of these. See also
d- and 1-chlorosuccinic acid (p. 499) and d- and l-malic acid (p. 551,
etc.).
Inactive [d+1] Aspartic Acid, Asparacemic Acid, C^HjCNHjXCOjH),, is
produced :
(1) By the union of 1- and d-aspartic acids.
(2) On heating active aspartic acid (a) with water, (6) with alcoholic ammonia
to 140-150°, or (c) with hydrochloric acid to 170-180° (B. 19, 1694).
(3) When fumarimide (p. 522) is boiled with hydrochloric acid.
(4) On heating fumaric and maleic acids with ammonia (B. 20, R. 557 ; 21,
R. 644).
(5) By evaporating a solution of hydroxylamine fumarate (B. 29, 1478).
(6) By reducing oximidosuccinic ester with sodium amalgam (B. 21, R. 351).
Benzoyl Asparacemic Acid is resolved into its optical components by means
of brucine (B. 32, 2461).
Like glycocoll, it combines with alkalis and acids yielding salts.
Nitrous acid changes it into inactive malic acid.
[d+1] Aspartic Diethyl Ester, NHt.C4Ha(CO2C2H6)2, b.p.26 150-154°, is pro-
duced on heating fumaric and maleic esters with alcoholic ammonia (B. 21, R.
86).
554 ORGANIC CHEMISTRY
NH2.CHC02C2H5
a-Aspartic Mono-ethyl Ester, \ , m.p. 165° with decomposition,
CH2CO2H
is formed by the reduction of a-oximidosuccinic monethyl ester and the oxime of
oxalacetic diethyl ester. Ammonia converts it into inactive a-asparagine (con-
stitution, comp. p. 555).
B-A spartic Mono-Ethyl Ester, , m.p. 200° with decomposition,
NH2.CHC02H
is also obtained from the oxime of oxalacetic ester by reduction with sodium
amalgam. A partial saponification occurs at the same time. Ammonia converts
it into the two optically active asparagines, which are therefore j8-aminosuccinamic
acids.
Phenyl Aspartic Acid, C6H6NH.CH(COaH(CH2CO2H, m.p. 131°, is formed
by the action of bromosuccinic acid on aniline. Phenyl Asparaginanil,
C6H5NHC2H3C,Oa.NC,H6, m.p. 210°, results on adding aniline to maleinanil
(A. 239, 137).
1-Aspartic Acid, m °T NHCOOH' occurs in the vinasse
obtained from the beet root, and is procured from proteins in
various reactions. It is obtained by the splitting of [d-j-1] aspartic
acid (see above), and from 1-asparagine by boiling it with alkalis and
acids (B. 17, 2929).
It crystallizes in small rhombic leaflets or prisms, and is not very soluble in
water. Nitric acid converts it into ordinary 1-malic acid (B. 28, 2769). 1- Aspartic
acid is laevo-rotatory in alkaline solutions, and dextro-rotatory in acids ; dextro
in aqueous solution at low temperatures, and Isevo at higher temperatures.
This behaviour may be due to dissociation of cyclic ammonium salts (above)
(B. 30, 294). Diethyl Ester, b.p.^ 126°, is formed from aspartic acid or asparagines
by alcohol and hydrochloric acid (B. 34, 452 ; 37, 4599) ; dimethyl ester, b.p.16
120° (B. 40, 2058).
d- Aspartic Acid results when d-asparagine is boiled with dilute hydrochloric
acid (B. 19, 1694) and from 1-chlorosuccinic acid (p. 499).
CHjCONH,
1- and d-Asparagine, | -f-HtO, are the monamides of
NHj.CHCOjH
the two optically active aspartic acids, and are isomeric with mala-
mide (p. 553). Crystallographically, they are identical as regards the
hemihedral surfaces (C. 1897, II. 1108).
Historical. — As early as 1805 Vauquelin and Robiquet discovered the laevo-
asparagine in asparagus. Liebig, in 1833, established its true composition.
Kolbe (1862) was the first to regard it as the amide of aminosuccinic acid. Piutti
(1886) discovered dextro-asparagine in the sprouts of vetches, in which it occurs
together with much laevo-asparagine.
Laevo-asparagine is found in many plants, chiefly in their seeds ;
in asparagus (Asparagus officinalis) , in beet-root, in peas, in beans, and
in vetch sprouts, from which it is obtained on a large scale, and also in
wheat. The laevo- and dextro-asparagines not only occur together in
the sprouts of vetches, but they are found together if asparaginimide,
produced from bromosuccinic ester, is heated to 100° with ammonia ;
or by the action of alcoholic ammonia on j3-aspartic ester (B. 20,
R. 510 ; B. 22, R. 243). A mixture of the two naturally occurring
asparagines has been produced by heating maleic anhydride to 110°
with alcoholic ammonia (B. 29, 2070).
AMINOSUCCINIC ACIDS 555
Both optically active asparagines crystallize in rhombic, right and
left hemihedral crystals, which dissolve slowly in hot water, in alcohol
and ether, but they are not easily soluble. It is not possible for them
to combine in aqueous solution to an optically inactive asparagine.
It is remarkable that the dextro-asparagine has a sweet taste, whilst
the • laevo-form possess.es a disagreeable and cooling taste. Pasteur
assumes that the nerve substance dealing with taste behaves towards
the two asparagines like an optically active body, and hence reacts
differently with each.
Similar differences of taste are observed with d- andl-valine (p. 389),
d- and 1-leucine (p. 390), and d- and 1-serine (p. 540).
Constitution of the Asparagines. — When the oxime of oxalacetic ester (i ) (below)
is reduced with sodium amalgam, either a- or /?-ethyl aminosuccinic acid (2 and 3)
is formed with a partial saponification, depending upon the conditions of the
reaction. The constitution of the a-acid, m.p. 165°, follows from its formation
by the reduction of the two probable spacial isomeric oximidosuccinic ethyl
ester acids (4), which split off CO2 and yield a-oximidopropionic acid (5) (p. 410).
Hence, it may be inferred that the acid melting with decomposition at 200°
contains the amino group in the £ -position with reference to the carboxethyl
group (B. 22, R. 241). Ammonia converts both acids into their corresponding
amino-acids. We obtain inactive a-asparagine (6) from the a-acid, and from the
j3-acid a mixture of the two optically active /3-asparagines (7) results :
ROCO.C:NOH _ ROCO.C:NOH _ ROCO.C:NOH
[) ROCO.CHa I - " HOCO.CH, I CH3
HOCO.CHNH, ROCO.CHNH,
(2) ROCO.CH2 I (3) HOCO.CH, I
HOCO.CHNH, d- and 1- NHaCO.CHNHa
'NHaCO.CH2 0-Asparagine (7' HOCO.CH, a- Asparagine
[d+l]-a- Asparagine, Isoasparagine, HOaC.CHaCH(NH2)CONH2, decomposes
at 214°, is formed from asparagine imide, aspartic dimethyl ester, and a-aspartic
mono-ethyl ester by the action of concentrated ammonia ; also, from the potas-
sium salt of aminofumaric monoamide (p. 566) and aluminium amalgam (C.
1897, I. 364).
Asparagine Diamide, NHaCO.CH(NH2)CHaCONHa, m.p. 131°, is prepared
from aspartic ester and fluid ammonia. It is very soluble in water, and is
easily decomposed. Asparagine Imide, Di-aci-piperazineDiacetamide, (C4H,ONt)2
(formula, see below), decomposes at 250°, is formed at the same time as asparagine
diamide (above). It forms needles, and is with difficulty soluble in water. It
is also prepared from bromosuccinic ester and ammonia ; and from Di-aci-
piperazine Diacetic Ester (formula, see below) ; methyl ester, m.p. 248°, ethyl ester,
m.p. 180-185°, by the same reagent. The latter ester is also obtained when
aspartic ester is heated (B. 37, 4599 ; 40, 2059) :
Hydrolysis of the ester or amide results in the formation of di-aci-piperazine
diacetic acid, and also the dipeptide.
Aspartyl Aspartic Acid, HOOC.CH2CH(CO2H)NHCOCH(NH2)CH2COaH.
The di- and tri-peptides of the aspartic series are prepared in the same way as the
peptides of the simple amino-acids (p. 391, etc.). and serine, cystine, etc. (pp. 540,
541 ), e.g. Glycyl Aspartic Anhydride, NHCH2CONHCH(CO)CH2.COOH, from chlor-
acetyl aspartic ester; Leucyl Asparagine, C4H,.CH(NHa)CONHCH(COaH)CH,-
556 ORGANIC CHEMISTRY
CONH2, from bromisocaproyl asparagine ; Aspartyl Dialanine, HO2CCH(CHa)-
NHCOCH2CH(NH2)CONHCH(CH3)CO2H, from fumaryl dialanine and am-
NHCHCO.NHCH(C4H,)C02H
monia : Glycyl A spartyl Leucine, from chlor-
NH2CH2COCH2CONH2
acetyl aspartyl chloride, C1CH2CONHCH(COC1)CH2CONH2, with leucine ester
and ammonia (B. 37, 4585 ; 40, 2048). Hippuryl Aspartic Acid, C6H5CO.NHCH2-
CONHCH(CO2H)CH2CO2H, is prepared from hippurazide (p. 388, Vol. II.), and
aspartic acid, and yields a diazide, which, reacting with aspartic ester, gives rise
to hippuryl aspartyl bis-aspartic ester, and still more complex chain compounds
(J. pr. Ch. 70, 158).
Malic Acid Homologues are formed : by the addition of hydrocyanic acid
to £-ketonic esters ; by the addition of HC1O to alkyl malic acids and subsequent
reduction ; and by the reduction of alkyl oxalacetic esters.
a-Hydroxypyrotartaric Acid, Citramalic Acid, a -Methyl Malic Acid,
CH8C(OH)CO,H
, m.p. 119°, is produced (i) in the oxidation of isovaleric acid
CH2.C02H
(p. 260) with nitric acid ; (2) from acetoacetic ester by means of HNC and HC1 ;
(3) by the reduction of chlorocitramalic acid, the addition product resulting
from the union of HC1O with citraconic acid ; (4) from methyl asparagine and
nitric acid. It breaks down at about 200° into water and citraconic anhydride
(B. 25, 196).
Citramalic acid is resolved into its optical components by means of brucine
(B. 32, 712). a-M 'ethyl Malic Nitrile Ester, Acetoacetic Ester Cyanhydrin,
CH3C(OH)(CN)CH2CO2C2H5, m.p. 8-5°, b.p.ie 127° (B. 39, 1858).
a-Aminopyrotartaric Acid, [d+l]-Homoaspartic Acid, HO2C.CH2C(CH3)-
(NH2)CO2H, m.p. 166°. Its diamide is formed from itaconic, citraconic, and
mesaconic esters by the action of ammonia (B. 27, R. 121). The acid is resolved
into its d- and 1- forms by crystallization. Methyl Asparagine, HO2C.CH2C(CH3)-
(NH2)CONH2 (?), m.p. 255° with decomposition, is formed from citraconic
acid and ammonia (C. 1898, II. 762). a-Anilinopyrotartaric Acid, HO2C.CH2C-
(CH3)(NHC,H8)CO2H, m.p. 135°, results from the hydrolysis of a-anilino-
pyrotartaric monoester nitrile, an oil, which is formed from acetoacetic ester
cyanhydrin and aniline ; also, from acetoacetic ester anil and hydrocyanic
acid. Ester Amide, m.p. 119°, is formed from the nitrile and sulphuric acid in
the cold ; it is easily converted into the imide, m.p. 168° (B. 35, 2078).
The anilinopyrotartaric acid when heated yields a-anilinopyrotartaric anil
and citraconic anil (A. 261, 138).
CH8.CHCO2H
fi-M ethyl Malic Acid, , is a colourless syrup, readily soluble
CH(OH)CO2H
in water, in alcohol, and in ether. It is formed when methyl oxalacetic ester is
reduced with sodium amalgam, and in an active 1- form from a citraconic acid
solution by the action of a mould (B. 27, R. 470). Mesaconic acid and citraconic
anhydride (B. 25, 196, 1484) are produced when it is heated.
Pp-Dimethyl Malic Acid [2,2-Dimethyl-3-butanol diacid], CO2H.CH(OH).-
C(CH8)2.CO2H, m.p. 129°, is obtained by the action of alkalis or hydrochloric
acid on the lactone. ^-Dimethyl Malic Lactone, OCHCCOjHJCfCH^aCq, m.p.
46°, -f- aq., m.p. 54°, is formed from monobromo-as.-dimethyl-succinic acid and
silver oxide. It was the first ft-lactone of the fatty acid series known (v. Baeyer
and Villiger, B. 30, 1 954). When distilled under reduced pressure it is transformed
into the anhydride, b.p.18 145-150° (B. 33, 3270) :
(CH8)2C— CO (CH8)2C OX
CO.H.CH.O HO.CH— CO/
a.p-Dimethyl Malic Acid, CH3C(OH)(CO2H)CH(CH8)CO2H, m.p. 143°, is
prepared from a-methyl acetoacetic ester cyanhydrin. During distillation it
is converted into pyrocinchonic anhydride (p. 518). This, when heated with
AMINOSUCCINIC ACIDS 557
alcoholic ammonia, is converted into Amino-dimethyl-succinic Imide
NH,C(CH3).C(\
>NH, m.p. 168° (B. 33, 1410).
HC(CH3).C(X
p-Ethyl Malic Acid, C2H6.CH(CO2H)CH(OH)COaH, m.p. 87° with decom-
position. Its orthotrichloride, a-Ethyl fi-Hydroxy^y-trichlorobutyric Acid, C2H5CH-
(CO2H)CH(OH)CC13, m.p. 137°, is formed from chloral, ethyl malonic acid, and
pyridme. When heated with potassium hydroxide it is changed into malic acid,
which on heating decomposes into water and ethyl maleic acid (p. 518) (B. 38, 2733).
ap-M 'ethyl Ethyl Malic Acid, m.p. 130° (B. 26, R. 190).
Trimethyl Malic Acid, Hydroxy-Trimethyl-Succinic Acid, m.p. 155°, is ob-
tained from dimethyl acetoacetic ester with hydrocyanic acid, with subsequent
hydrolysis by hydrochloric acid (B. 29, 1543, 1619). The corresponding fi-lactone
acid, OC(CH3)(CO2H).C(CH3)2CO, m.p. 119°, is obtained from bromo-trimethyl-
succinic acid and silver oxide, similarly to the production of /?j8-dimethyl malic
acid lactone.
Isopropyl Malic Acid, m.p. 154°, from bromopimelic ester (A. 267, 132).
Paraconic Acids are y-lactonic acids. Like the y-hydroxyalkyl hydroxymalonic
acids, they are converted by alkalis and alkali earths into salts of the corre-
sponding hydroxysuccinic acids. When the latter are set free from their salts
they immediately break down into water and lactonic acids. The alkyl paraconic
acids are formed when sodium succinate or pyrotartrate and aldehydes (acetal-
dehyde, chloral, propionic aldehyde) are condensed by means of acetic anhydride
at 100-120° (Fittig, A. 255, i) :
CHa.CO2H CH3.CH— CH.CO2H
CH3.CHO+ | = +HaO
CH2.COjH O.CO.CHj
Succinic Acid. Methyl Paraconic Acid.
CHa— CHC02H
Paraconic Acid, | , m.p. 57°, is best prepared by boiling
O.CO.CHa
itabromopyrotartaric acid with water and acidifying the calcium salt of the
corresponding hydroxysuccinic acid — itamalic acid, formed on boiling itachloro-
pyrotartaric acid with a soda solution. When boiled with bases, it forms salts
of itamalic acid ; it yields citraconic anhydride when it is distilled (A. 216, 77 ;
255, 10).
CHa— CHCO,H
Pseudoitaconanilic A cid, v-A nilidopyrotartrolactamic A cid, ,
CaH5.N.CO.CH,
m.p. 190°, is formed from itaconic acid (A. 254, 129), by the addition of anilin^,
and subsequent lactam formation.
CHaCH— CHC02H
y-Methyl Paraconic Acid, , m.p. 84-5°. Ethyl ester, b.p.17
O.CO.CH,
56°, is also prepared from acetosuccinic ester by reduction with amalgamated
'• aluminium. Sodium ethoxide solution transforms and hydrolyses it into
methyl itaconic acid. When distilled, methyl paraconic acid yields valerolactone
ethylidene propionic acid (p. 298), methyl itaconic acid, and methyl citraconic
acid (B. 23, R. 91).
CC13.CH— CHCOjH
Trichloromethyl Paraconic Acid, , m.p. 97°, is changed by
O.CO.CHa
cold barium hydroxide solution into isocitric acid (q.v.). Reduction (C. 1897,
II. 184; 1902, II. 343).
CH3CH,CH— CH.CO,H
Ethyl Paraconic Acid, , m.p. 85° C., when dis-
O.CO.CH,
tilled, breaks up chiefly into carbon dioxide and caprolactone (p. 374). Hydro-
sorbic Acid is formed at the same time (B. 23, R. 93)-
a~M ethyl Paraconic Acid, CH8CH(CO)CH(COaH)CH,O, m.p. 104°, is obtained
558 ORGANIC CHEMISTRY
bv the action of sodium amalgam on £-formyl pyrotartaric ester, the reaction
product of formic ester, pyrotartaric acid and sodium ethoxide. When heated
it decomposes partly into water and pyrocinchonic anhydride (p. 518) (B. 37,
I6xo). .
ay-Dimethyl Paraconic Acid, CH8CH(CO)CH(COOH),CH(CH8)O, m.p. 131°,
b p ' 195°, is formed by reducing jS-acetopyrotartaric ester with sodium amalgam.
When heated it partially breaks down into water and methyl ethyl maleic
anhydride (p. 519), and into CO, and a-methyl j3-pentenoic acid (CH,CH(CO2H)-
CH:CHCH, (B. 37 1615).
(CH3)2C CHCU,tl
Terebic Acid, I •
O.CO.CHj
(CH8)2C CHCH2CO,H
Terpenylic Acid, I 1 •
. U — L/U — Url 2
(CH8)3C CHCH2CH2C02H
and Homoterpenylie Acid, are three oxidation
O . CO . CH2
products of turpentine oil. They will be discussed in connection with pmene
(Vol. II.), the principal ingredient of the oil.
Propyl Paraconic Acid, CH8CH2CH2.CH(O)CH(CO2H)CH2CO, m.p. 73-5°,
yields, on distillation, y-heptolactone (p. 375), heptylenic acid, C7H12O2, and
propylitaconic acid, C^12Ot (p. 518) (B. 20, 3180).
Isopropyl Paraconic Acid, m.p. 69°. when distilled, decomposes into
y-isoheptolactone and isoheptylenic acid.
I |
Isopropyl Isoparaconic Acid, (CH8)2C(O)CH2CH(CO).CH2CO2H, m.p. 143°, is
formed from isopropyl itaconic acid (p. 5*7) and hydrochloric acid at 130°,
and by oxidation of isobutyl succinic acid by means of KMnO4.
aap-Trimethyl Paraconic Acid, OCH2.C(CH8)(CO2H).C(CH8)2CO, m.p. 270°,
is formed from sodium trimethyl succinate and thioxymethylene, by the action
of acetic anhydride. Ethyl ester, m.p. 34° ; chloride, m.p. 140° ; amide, m.p. 242°.
The anhydride, m.p. 155°, is obtained, together with Trimethyl Acetyl Itamalic
Anhydride, OOC.C(CH3)2.C(CH8)(OCOCH8)CO, b.p.2a 185-195°, from tri-
methyl itamalic acid salts by boiling them with acetic anhydride (C. I9°5» I.
*374)-
HYDROXYGLUTARIC ACID GROUP
a-Hydroxyglularic Acid, CH2<^^Q^OaH , m.p. 72°, occurs in molasses. It
is formed from a-bromoglutaric acid (C. 1902, II. 187) ; and by the action of
nitrous acid on a-aminoglutaric acid. It also occurs in the reaction products of
nitric acid on casein (C. 1902, II. 285). It crystallizes with difficulty (A. 208,
66; B. 15, 1157). Its lactone, m.p. 50°, into which it readily passes when
heated (A. 260, 1129), is reduced to glutaric acid (p. 501) by hydriodic acid.
Glutaminic Acid, a-Aminoglutaric Acid, CH^jj^ m.p. 202°
with decomposition, contains an asymmetric carbon atom (p. 29), and therefore
can, like malic acid (p. 551), appear in three modifications. Dextro- or ordinary
glutaminic acid occurs in the seeds of pumpkins and of vetches, as well as
with aspartic acid in the molasses from beet-root, and is formed along with
other compounds (p. 381) when proteins are boiled with dilute sulphuric acid.
It consists of brilliant rhombohedra, soluble in hot water but insoluble in alcohol
and ether. Diethyl Ester, b.p.IO 140°, is prepared from the acid, alcohol, and
hydrochloric acid (B. 34, 453).
HYDROXYGLUTARIC ACID GROUP 559
\-Glutaminic Acid is obtained from the inactive variety by means of Penicillium
glaucum (p. 57).
Inactive [d-\-l]-Glutaminic Acid, m.p. 198°, results from ordinary glutaminic
acid on heating it to 150-160° with barium hydroxide solution, and from a-iso-
nitrosoglutaric acid (A. 260, 119). By repeated crystallization it breaks down
into d- and 1-glutaminic acid (B. 27, R. 269, 402 ; 29, 1700). Resolution
is also effected by means of the strychnine salts of r-benzoyl glutaminic acid
(B. 32, 2466). [d-f-l]-Pyroglutaminic Acid, m.p. 182-183°, is the y-lactam of
the glutaminic acid, which results on heating ordinary glutaminic acid to 190°,
and on continued heating breaks down into CO, and pyrrole (B. 15, 1342) :
COCH2CH2CH(COaH)NH > CH:CH.CH:CH.NH+CO,+HtO
Pyroglutamine Acid. Pyrrole.
Glutamine a-Aminoglutaramic Acid, C3H5(NHa)<£^2*' occurs together
with asparagine in beet-root, in the seeds of pumpkins and other plants (B. 29,
1882, C. 1897, I. 105). Its optical rotation is not constant (B. 39, 2932).
y-Carbovalerolactonlc Acid, a-Methyl Glutolactonic Acid, Valerolactone
y-Carboxylic Acid, O.C(CH8)(COaH)CHaCH2CO, m.p. 68-70°, is deliquescent,
and is produced (i) by oxidizing y-isocaprolactone (p. 374) or isocaproic acid
with nitric acid (A. 208, 62 ; B. 32, 3661) ; and (2) by the action of potassium
cyanide and hydrochloric acid on laevulinic acid.
y-Carbovalerolactamic Acid Nitrile ; a-Methyl Pyrrolidone a-Carboxylic Acid
Nitrile, HNC(CH,)(CN).CH2.CH2.CO, m.p. 141°, is formed from laevulinic
ester, hydrocyanic acid, and alcoholic ammonia (comp. B. 38, 1215).
Isopropyl Glutolactonic Acid, CO2H.C(C8H7)CH2.CH2COO, m.p. 67°, is pre-
pared from a-dimethyl laevulinic acid and hydrocyanic by means of
hydrochloric acid (A. 288, 185). a-Hydroxy-yy-dimethyl-glutolactonic Acid,
O.CH(COaH).CH2C(CHa)2CO, m.p. 85° (indefinite), results, together with
dimethyl glutaconic acid, when alcoholic potassium hydroxide acts on a-bromo-
dimethyl glutaric acid (C. 1902, I. 810 ; comp. also cyano-dimethyl-acetoacetic
ester, p. 570). a-Hydroxy-py-dimethyl-glutolactonic Acid, trans-form, m.p. 142°,
et's-form, liquid, b.p.15 194°, is formed from )3-methyl laevulinic acid, hydro-
cyanic and hydrochloric acids (C. 1900, II. 242). a-Hydroxy-ayy-trimethyl-
glutolactonic Acid, O.C(CH8)(CO2H)CHaC(CH8)2CO, m.p. 103°, is prepared from
bromo-trimethyl-glutaric acid and aqueous potassium hj'droxide, and from
mesitonic, hydrocyanic and hydrochloric acids (A. 293, 220).
Mesitylic Acid, a-Amino-ayy-trimethyl-glutaric Acid Lactam, HNC(CH,)(COjH)-
CH2C(CH8)2CO, m.p. 174°, is prepared by boiling the addition product of mesityl
oxide and hydrochloric acid with potassium cyanide and alcohol (see Mesitonic
Acid, p. 423). If mesityl oxide alone be heated with two molecules of potassium
cyanide in alcohol, there is formed on acidification Trimethyl-a-hydroxy-glutaric
Acid Dinitrile, NC.C(CH8)aCH8C(CH,)(OH)CN, m.p. 166°, which on being
warmed with hydrochloric acid yields mesitylic acid (C. 1904, II. 1108). Oxida-
tion with permanganate in acid solution yields unsym.-dimethyl succinimide
(B. 14, 1074).
fi-Hydroxyglutaric Acid, CH(OH)<^HaCO2H' m'P' 95°» is obtained bv the
reduction of an aqueous solution of acetone dicarboxylic acid (B. 24, 325<>)- I* is
decomposed on distillation into COa, HaO and vinyl acetic acid (p. 297) ; Sul-
phuric acid and also boiling with aqueous alkali hydroxides (B. 33, 1452) produce
glutaconic acid (p. 520). Acetyl chloride gives rise to Acetoxyglutanc Anhydride,
CH,COOCH(CHaCO)aO, m.p. 88°. Hydroxyglutaric Dimethyl Ester, b.p.u 150 ,
yields acetoxy glutaric ester, which on distillation under ordinary pressures breaks
down into glutaconic ester (B. 25, 1976 ; C. 1903, II. 1315). ^-Hydroxyglutaric Di-
amid* is converted by sulphuric acid into glutaconimide. p-Chloroglutanc Acid is
560 ORGANIC CHEMISTRY
obtained from glutaconic acid and hydrochloric acid. From it and from glutaconic
acid ammonia produces fi-Aminoglutaric Acid, COaH.CHaCH(NHa)CHaCOaH,
m.p. 248° with decomposition. fi-Bromoglutaric Acid, m.p. 139° (C. 1899, II. 28).
sym.-Alkyl fi-Hydroxyglutaric Acids are also formed by condensation of
formic ester with a-bromo-fatty esters by means of zinc (see formation of
secondary alcohols, p. 106) ; a-bromopropionic ester yields ay-Dimethyl /J-
Hydroxy glutaric Acid; a-bromobutyric acid gives ay-Dimethyl p-Hydroxy-
glutaric Acid; a-bromoisobutyric ester produces aayy-Tetramethyl fi-Hydroxy-
glutaric Acid (C. 1898, II. 415, 885 ; 1900, II. 529 ; 1902, II. 107).
aa-Dimethyl fi-Hydroxyglutaric Acid, m.p. 169°, and aay-Trimethyl fi-Hydroxy-
glutaric Acid, cis-iorm, m.p. 115° ; trans-iorm, m.p. 155°, arc obtained from the
corresponding di- and trimethyl acetone dicarboxylic esters (p. 569) (C. 1903, I.
76 ; 1904, I. 720). aafi-Trimethyl ft -Hydroxy glutaric Ester is prepared from
a-dimethyl acetoacetic ester, bromacetic ester, and zinc (C. 1903, II. 1315).
The acetylated esters of these acids yield alkyl glutaconic acids when distilled.
CH(COaH)CHaCH2CO
B-Caprolactone y-Carboxylic Acid, I , m.p. 197°, is formed
CH3CH— — O
when a-acetoglutaric acid (p. 570) is reduced (B. 29, 2368). On dry distillation
it yields yS-hexenic acid (p. 299) and a-ethylidene glutaric acid (p. 522).
y-Valerolactone fi-Acetic Acid, CO\rjr CHCH^CO H' m'P' ^4° » oy-Hepto-
lactone fi-Acetic Acid, m.p. 88°, are obtained by reduction of the j3-acyl glutaric
acids (p. 570), or their dilactones (A. 314, 13).
HIGHER HYDROXY-DICARBOXYLIC ACIDS
aa-Hydroxyadipic Acid (B. 28, R. 466). a-Hydroxysebacic Acid (B. 27,
1217).
a-Hydroxy-a-methyl-adipic Acid, CO2H.C(CH3).(OH)[CH2]3CO2H, m.p. 92°.
is prepared from y-acetobutyric acid, potassium cyanide, and hydrochloric acid.
On dry distillation it gives a mixture of yS- and Se-hexenic acids, which are
characterized by their ability to be converted into a- and 8-caprolactone (A. 313,
37*)-
B-Methyl p-Hydroxyadipic Acid, COOH.CH8C(CH3)(OH)CH2CHaCOOH, and
aay-Trimethyl p-Hydroxyadipic Acid, CO2H.C(CH3)2C(CH3)(OH)CH2CH2COOH ;
their lactone esters are formed by condensation of bromacetic ester and a-brom-
isobutyric ester with laevulinic acid by means of zinc. The latter lactone ester is
easily decomposed by alkalis into isobutyric acid and laevulinic acid (C. 1900, I.
1014 ; B. 36, 953)-
a-Amino-adipic Acid, COOH.CH(NH2)CH2CH2CH2CO2H, m.p. 206° with
decomposition, is formed from a-oximido-adipic acid (p. 570) by reduction
with tin and hydrochloric acid ; also, by hydrolysis and decomposition of
cyanopropyl phthalimidomalonic ester, C6H4(CO)2NC(CO2R)aCH2CHaCH2CN,
the product of reaction of sodium phthalimidomalonic ester and chlorobutyro-
nitrile. It is sparingly soluble in water. When heated, it yields water and
a lactam, a-Piperidone ^-CarboxylicA cid, NHCH(COaH)CH2CH2CHaCO, m.p. 178°.
a-Amino-fi-methyl-adipic Acid is prepared from a-oximido-/3-methyl-adipic acid.
In the free state it immediately changes into its lactam, m.p. 144° (B. 38, 1654 ;
C. 1903, II. 33). a-Aminopimelic Acid, NH2CH(COOH)[CHa]4COOH, m.p. 225°
with decomposition, is obtained from a-oximidopimelic acid.
B. AND C. HYDROXY-OLEFINE CARBOXYLIC ACIDS AND HYDROXY-
OLEFINE DICARBOXYLIC ACIDS
The following is derived from the true olefme-hydroxy-dicarboxylic acids :
Monolactonic Acid, OCOCH:CH.CHCH2COOH (?), m.p. 122-125°, is obtained
from hydromuconic dibromide and silver oxide.
The aci- or enol-iorms of the fi-aldo- a.nd.p-keto-dicarboxylic acids can also be in-
cluded ; seeformyl and acetyl malonic acids (pp. 561, 56,\),formyl and acetyl succinic
acids (pp. 561, 568), a-acetyl glutaric acid (p. 570), oxalacetic acid (p. 564), acetone-
dicarboxylic acid (p. 568), a~formyl and a-acetyl glutaconic acid (pp. 561, 571), etc.
ALDODICARBOXYLIC ACIDS 561
l6. ALDODICARBOXYLIC ACIDS
A. /J-Aldodicarboxylie Acids. The simplest member, (i) Formyl Malonic
Acid, OCH.CH(CO2H)2, is unknown in the free state. From its corresponding
aci- or enol-iono. (see p. 560) are derived the following : —
Hydroxymethylene Malonic Ester, HOCH:C(CO2C2H6)2, b.p. 218°, exists in
the fonn of its ethyl ether, Ethoxymethylene Malonic Ester, C2H6O.CH:C(CO2C2H6)2,
b.p. 280°, which is prepared from malonic ester and orthoformic ester by boiling
with acetic anhydride and zinc chloride. The ethyl ether is " hydrolysed "
by alcoholic potassium hydroxide into the potassium salt of hydroxymethylene
malonic ester. It can also easily unite with more malonic ester to form a
dicarboxyglutaconic ester (RO2C)2CH — CH=C(CO2R)2. This substance is
decomposed by many reactions into derivatives of hydroxymethylene malonic
ester ; ammonia produces Aminomethylene Malonic Ester, H2N.CH:C(CO2C2H5)2,
m.p. 67°, which can be formed directly from ammonia and ethoxymethylene
malonic ester ; hydrazine, hydroxylamine, and amidines give rise to cyclic deriva-
tives of hydroxymethylene malonic or formyl malonic acids (B. 26, 2731 ; 27,
1658 ; 30, 821, 1083 ; J. Ch. S. 59, 746). Copper salt, m.p. 138°.
(2) Formyl Succinic Acid, OCH.CH(CO2H)CH2CO2H is unknown in the free
state. Derivatives are : Hydroxymethylene Succinic Ester, aci-Formyl Succinic
Ester, HOCH:C(COjC2H6)CH2CO2C2H6, b.p.16 125°, is obtained from succinic
ester, formic ester, and sodium ethoxide. With ferric chloride it produces a
violet coloration. Reduction produces itamalic ester (p. 557), alkalis decompose
it into succinic and formic acids (B. 26, R. 91 ; 27, 3186. Action of Hydrazine,
see B. 26, 2061).
Aconic Acid: aci-Formyl Succinic Acid Lactone, OCH:C(CO2H)CH2CO,
m.p. 164°, is formed when itadibromopyrotartaric acid is boiled with water ;
methyl ester, m.p. 85°. The acid yields formic and succinic acids when boiled
with barium hydroxide ; reduction produces paraconic acid (p. 557) ; phenyl-
hydrazine gives the phenylhydrazone of jS-formyl propionic hydrazide (p. 406)
as well as CO2 ; whilst with aconic methyl ester it forms the phenylhydrazone,
of formyl succinic monoester phenylhydrazide, m.p. 167° (A. Spl. I. 347 ; 329,
373 ; B. 31, 2722).
Formyl Pyrotartaric Ester (B. 37, 1610).
(3) a-Formyl Glutaconic Acid, OCH.CH(CO2H)CH:CHCO8H, is also a hypo-
thetical acid, of which the following are derivatives: —
Coumalie Acid, a-Pyrone-^-carboxylic Acid, a-a.ci-Formyl Glutaconic Acid
Lactone, OCH:C(CO2H)CH:CH.CO, m.p. 206° with decomposition, is formed from
malic acid by heating it with concentrated sulphuric acid or with zinc chloride,
with probably an intermediate formation of hydroxymethylene acetic
acid, HOCH:CHCO2H (p. 401), which, with the concentrated sulphuric acid,
gives coumalic acid. This substance yields yellow salts with excess of alkali,
like chelidonic and meconic acids (q.v.). Boiling with barium hydroxide solution
decomposes it into formic and glutaconic acids ; boiling with dilute sulphuric
acid gives two molecules of CO2 and crotonaldehyde. Ammonia produces the
aci-formyl glutaconic acid lactam, (3-hydroxynicotinic acid, HN.CH:C(CO2H):-
CHrCHCO. Hydrazine causes decomposition of the production of the lactazam
of hydroxymethylene acetic acid, pyrazolone (p. 406) (A. 264, 269 ; B. 27, 791).
Methyl alcohol and hydrochloric acid cause fracture of the lactone ring and forma-
tion of
MethoxymethyleneGlutaconic Ester, CH3COCH:C(CO2CH,)CH:CHCO2CH8, m.p.
62° (A. 273, 164).
B. y-Aldodicarboxylic Acids.
Acetal Malonic Ester, (C2H6O)2CHCH2(CO2C2H6)2, b.p.1B 152°, and acetal
methyl malonic ester are prepared from sodium malonic ester and sodium methyl
malonic ester with bromacetal. The free acids lose water and form jS-forrayl
fatty acids (p. 402).
VOL. I. 2, Q
562 ORGANIC CHEMISTRY
17. KETONE-DICARBOXYLIC ACIDS
Dibasic carboxylic acids, containing a ketone group in addition to
the carboxyl groups, are mostly synthesized as follows :•—
1. By the introduction of acid radicals into malonic esters.
2. By introducing the residues of acid esters into acetoacetic ester.
3. By the condensation of oxalic esters with fatty acid esters.
4. By condensation of carboxylic anhydrides with tricarballylic
acids.
5. From sec.-hydroxydicarboxylic acids or tert.-hydroxytricar-
boxylic acids by oxidation or decomposition.
These methods of formation will be more fully considered under the
individual groups of the monoketone carboxylic acids. The position
of the two carboxyl groups is again the basis for their classification,
whereby the ketomalonic acid group, the ketosuccinic acid group, the
ketoglutaric acid group, etc., are differentiated.
KETOMALONIC ACID GROUP
(i) Mesoxalic Acid, Dihydroxymalonic Acid, [Propanediol diacid],
m.p. 115°, like ordinary oxalic acid, glyoxylic acid, and other sub-
stances possessing adjacent CO groups, firmly holds a molecule of
water, which is assumed to be present, not as water of crystallization, but
to be combined with the CO-groups :
(HO),C— C(OH), (HO)2CH— C02H (HO)aC=(COaH)t
Ortho-oxalic Acid. Orthoglyoxylic Acid. Orthomesoxalic Acid.
Furthermore, esters of mesoxalic acid exist, derived from both
forms, and are known as oxo- and dihydroxymalonic acid esters.
Mesoxalic acid is prepared (i) from alloxan (p. 578) or mesoxalyl
urea, an oxidation product of urea when boiled with barium hydroxide
solution ; (2) from dibromomalonic acid, by boiling barium hydroxide
solution, silver oxide, or aqueous sodium hydroxide (method of for-
mation : B. 35, 1819) ; (3) from aminomalonic acid by oxidation
with iodine in KI solution ; (4) from glycerol, by oxidation with
nitric acid, sodium nitrate, and bismuth subnitrate (B. 27, R. 666).
Mesoxalic acid crystallizes in deliquescent prisms. At higher
temperatures it decomposes into CO2 and glyoxylic acid, CHO.CO2H
(p. 400). It breaks up into CO and oxalic acid on the evaporation
of its aqueous solution.
Mesoxalic acid behaves like a ketonic acid, inasmuch as it unites
with primary alkali sulphites ; and when acted on by sodium
amalgam in aqueous solution, it is changed to tartronic acid
(p. 549). It combines with hydroxylamine and phenylhydrazine.
Salts, — Calcium mesoxalate, C(OH)2(CO2)2Ca, and barium mesoxalate, are
crystalline powders, not very soluble in water; ammonium salt, C(OH)2.(CO2.-
NH4)2, crystallizes in needles ; silver salt, C(OH),.(CO2Ag),, when boiled with
NITROGEN DERIVATIVES OF MESOXALIC ACID 563
water yields mesoxalic acid, silver oxalate, silver, and CO, ; bismuth salt. B. 27,
R. 667.
Esters. — Two series of esters may be derived from mesoxalic acid
— the anhydrous or ketomalonic esters, CO(C02R')2> and the di-
hydroxymalonic esters, C(OH)2(CO2R')2- The keto- or oxo-malonic esters
absorb water with avidity, and thereby change into their corresponding
dihydroxymalonic esters. The two compounds bear the same relation
to each other that chloral bears to chloral hydrate :
CC13.CHO Chloral -^ CC13.CH(OH), Chloral Hydrate
CO(CO2CaH6)2Ketomalonic Ester — - — >- C(OH)2(COaCaHB)a Dihydroxymalonic Ester.
During preparation a mixture of both forms is obtained if water is not excluded.
Nevertheless, the hydrates easily pass into the anhydrous compounds when
heated under reduced pressure.
Mesoxalic ester is produced (i) from mesoxalic acid, by the usual methods ;
(2) from isonitrosomalonic ester (below) ; or from malonic ester direct by the
action of nitrous gases (C. 1903, II. 658 ; 1905, II. 120 ; 1906, II. 320) :
N203 Nao,
2(R02C)aCHa > 2(ROaC)aC : NOH > 2(ROaC)aC: O-f 2NaO-f-HaO
(3) From bromotartronic ester acetate or bromonitromalonic ester by the action
of heat (B. 25, 3614 : 37, 1775) :
— CH3COBr — NOBr
(ROaC)aC(OCOCH,)Br — — >- ROaC.CO •< BrNOaC(COaR)a
(4) from dihydroxysuccinic ester when heated, some oxalic ester being also formed
(B. 27, 1305):
ROjC.CO -co ROa(\ -co ROSC
| > >CO >•
ROaC.CO ROaC/ RO,C.
Ketomalonic Ethyl Ester, CO(COaC2H8)a, b.p.14 101°, Die= 1-1358, possesses
a bright greenish-yellow colour. It is a mobile liquid, with a faint but not dis-
agreeable odour. Dihydroxymalonic Methyl Ester, (HO)aC(COaCH3)a, m.p. 81°.
Dihydroxymalonic Ethyl Ester, C(OH)a(COaCaH8), m.p. 57°, dissolves easily in
water, alcohol, and ether. Diethoxy malonic Ester, (CaH6O)2C(COaCaH,), m.p.
43°, b.p. 225° (C. 1897, II. 569). Diacetoxymalonic Ester, (CH,CO.O)aC(COaCaHf)a,
m.p. 145°. Dihaloid-malonic Acids, HaC(COaH)a (p. 489).
Nitrogen Derivatives of Mesoxalio Acid.
Nitrobromomalonic Acid, BrNOaC(COaR)a ; methyl ester, b.p.lt 133°, and
ethyl ester, b.p.n 137°, are formed from nitromalonic ester (p. 549) and bromine.
As in other per-substituted nitromethanes (p. 155) the halogen is easily replace-
able. Decomposition into ketomalonic ester (see above) (B. 37, 1775).
Diaminomalonamide, (NHa)aC(CONHa)2, is prepared from dibromomalonic
ester and ammonia. It consists of white crystals, and when heated, easily changes
into imidomalonamide, NH : C(CONH,)a. Tetramethyl Diaminomalonic Ester,
[(CH?)2N]2C(COOCH3)2, m.p. 84°, is also obtained from dibromomalonic ester
and NH(CH3)2. Dianilinomalonic Ester, (C6H6NH)2C(COOCH3)2, m.p. 125°,
results from the action of aniline on dibromomalonic ester (B. 35, 1374 ; 1813).
Oximidomesoxalic Acid, Isonitrosomalonic Acid, HON=C(CO2H)2, m.p. 126°,
with decomposition into HNC, COa, and HaO. It is formed when hydroxylamine
acts on mesoxalic acid ; also from violuric acid (described in connection with
alloxan — isonitroso-malonyl-urea (B. 16, 608, 1021) ; also from isonitrosomalonic
ester, HON : C(CO2R)a ; methyl ester, m.p. 67°, b.p.lt 168°, ethyl ester, b.p.ia 172°,
which are prepared from the malonic ester, sodium alcoholate, and alkyl nitrites.
They form yellow alkali salts. Amides and alkyl amides of isonitrosomalonic
acid (C. 1903, 1. 441, 448).
Oximidomesoxalic Nitrite Ester, Isonitrosocyanacetic Ester, HON:C(CN).-
COtCaHj, m.p. 128°, is formed from sodium cyanacetic ester and amyl nitrite.
564 ORGANIC CHEMISTRY
It is a stronger acid than acetic acid (B. 24, R. 595 ; C. 1902, II. 1412). The free
isonitrosocyanacetic acid, m.p. 129° with decomposition, has been obtained in
different ways : (i) from dihydroxytartaric acid (q.y.) and hydroxylamine, some
dioximidosuccinic acid being formed at the same time ; (2) from furazan dicar-
boxylic acid, the anhydride of dioximidosuccinic acid (3) from furazan mono-
carboxylic acid (p. 545) (B- 24, 1988 ; 28, 72) :
HON:C.C08H /N:C.CO2H N:C.COaH HON:C.CO2H
HON:CC02H *:C.CO2H tf:CH NjC
(4) by the action of N2O3 on isoxazolone hydroxamic acid, prepared from oxal-
acetic ester and 2 molecules of NH2OH (see p. 567) (B. 28, 761). Further
derivatives of isonitrosomalonic acid are : isonitrosocyanacetamide, desoxyfulmi-
nuric acid, HON: C(CN)CONHa (p. 251): Isonitrosocyanacetohydroxamic acid,
HON:C(CN)C<C^Qjj, is prepared from formyl chloridoxime and NH3 (pp. 243,
i - N
249). Oxy furazan Carboxylic Acid, , is formed from hydroxy-
ON:C(C02H).COH
furazanacetic acid (see Oxalacetic Ester, p. 566).
Phenylhydrazonomesoxalic Ester, C6H6NHN:C(CO2R)2, dimethyl ester, m.p.
62° ; diethyl ester, an oil, is prepared (i ) from mesoxalic ester and phenylhydrazine :
(2) from sodium malonic ester and benzene diazonium salts (B. 24, 866, 1241 ;
25,3183; 28,858; 37,4169).
Hydrolysis causes the formation first of the monomethyl ester, m.p. 125°, and
monoethyl ester, m.p. 115°, and then of Phenylhydrazonomesoxalic Acid,
C,H6NHN : C(CO2H), m.p. 163° with decomposition, which can also be obtained
from mesoxalic acid and phenylhydrazine. Phenylhydrazonomesoxalic Ester
Nitrile, Benzene Azocyanacetic Ester, C6H5NHN : C(CN)CO2C2H6, or C6H6N :
NCH(CN)CO2C2H6, m.p. 125°, is formed from sodium cyanacetic ester and
benzene diazonium chloride (B. 27, R. 393 ; 28, R. 997 ; C. 1906, II. 625) ; and
also from potassium malonitrile and benzene diazonium salts. Phenylhydrazono-
mesoxalic Dinitrile, C6H6NHN : C(CN)2 (B. 29, 1174). Phenylhydrazonomesoxalic
Diamide, m.p. 232° (B. 37, 4173).
Hydrazonomesoxalic Diamide, NH2N:C(CONH2)2, m.p. 175°, is formed from
dibromomalonic diamide and hydrazine (B. 28, R. 1052).
Oxazomalonic Acid is formed by the action of nitric oxide and sodium ethoxide
on malonic ester. The product of reaction is unstable and forms a sodium salt,
N2O : C(CO2Na)2+2H2O, with aqueous sodium hydroxide. This and other salts
readily explode, especially when dry (B. 28, 1795).
(2) Acetyl Malonic Acid, CH3CO.CH(CO2H)2; ethyl ester, b.p.17 150°, results
when sodium or, better, copper acetoacetic ester is acted on by chlorpcarbonic
ester (p. 419) (B. 21, 3567 ; 22, 2617). On hydrolysis it decomposes into CO,,
acetone, and acetic acid. Acetomalonic MonoesterAnilide, CH3CO.CH(CONHC6H6)-
CO2C2H5, m.p. 58, is formed by the union of acetoacetic ester and phenyl cyanate.
It is decomposed by alkalis in the cold into acetic acid and malonic acid anilide
(B. 33,2002).
Acetyl Cyanacetic Ester, Cyanaceto acetic Ester, CH3CO.CH(CN).CO2C2H5,
m.p. 56°, b.p.16.20 119°, is prepared (i) from the sodium or pyridine salt of cyan-
acetic ester and acetyl chloride ; if acetic anhydride be employed, cyanacetyl
acetone is also formed ; (2) from dicyanacetoacetic ester (p. 417) by separating
hydrocyanic acid by alkalis. When the salts of cyanacetoacetic ester are alkylated
and acylated O-derivatives of the enolfrom result : CH3C(OCH3) : C(CN)CO2CH8,
m.p. 97°; CH3C(OCOCH8):C(CN)CO2CH3 and ammonia yield CH3C(NH2):-
C(CN)COaCH3, m.p. 181° (C. 1904, I. 1135 ; B. 37, 3384). Propionyl Cyanacetic
Ester, b.p.M 155-165° (B. 21, R. 187, 354 ; 22, R. 407 ; C. 1899, I. 185).
KETOSUCCINIC ACID GROUP
t. Oxalacetic Acid, Ketosuccinic Acid [Butanone di-acid], C4H4O5,
is relatively stable in the free state, and is simultaneously an a- and
OXALACETIC ACID 555
/3-keto-acid. In this connection, the desmotropic enol formulae of
hydroxymalei'c and hydroxyfumaric acids should be compared :
CHa— COOH CH COOH HOCO— CH
CO— COO
)H C(OH)— COOH HO.C-COOH
Ketosuccinic Hydroxymalei'c Hydroxyfumaric Acid.
Acid. Acid.
Oxalacetic acid is prepared (i) from synthetic oxalacetic esters
(p. 566) by hydrolysis with concentrated hydrochloric acid in the cold
(C. 1904, I. 85) ; (2) from malic acid (hydroxysuccinic acid) and per-
manganate or H2O2 and ferrous salts at a low temperature (C. 1900,
I. 328 ; 1901, 1. 168) ; (3) from teraconic acid (isopropylidene succinic
acid (p. 518) by cleavage of the chain with permanganate ; (4) from
diacetyl tartaric anhydride (q.v.) or acetoxymaleic anhydride (see
below), pyridine and acetic acid, there is formed the pyridine salt of
hydroxymaleic anhydride which with dilute acids yields oxalacetic
acid or hydroxymaleic acid respectively (B. 40, 2282) :
CH8COO.CHCO\ CH3COO.CCOV CBH6N
I >0 > II >0 >
CH.COO.CHCCK HCOX
C,H5NO.C CO. HOC.OX
I II >o > II >o
H CH— CO/ HC.CO /
When the pyridine salt of hydroxymaleic anhydride is treated
with 12% sulphuric acid, the Hydroxymaleic Acid, m.p. 152°, is formed,
which is converted by 30% acid into Hydroxyfumaric Acid, m.p. 184°,
from the salts of which dilute acids regenerate hydroxymaleic acid ;
probably ketosuccinic acid is formed as an intermediate product.
Hydroxyfumaric and hydroxymaleic acids show equally strong
colorations with ferric chloride and decolorations with permanganate
(reactions of the enol group). The heat of combustion of hydroxy-
maleic (286*58 cals.) is io'8 cals. more than that of hydroxyfumaric
acid (see Fumaric or Maleic Acids, pp. 60, 512).
Hydroxymaleic Anhydride, &ci-0xalacetic Anhydride, HO.CaH(CO)aO, m.p. 85°
with transformation, is prepared from the pyridine salt, m.p. 108° (see above),
by the action of HC1 in ether. It is very hygroscopic. Acetyl chloride produces
from it Acetoxymaleic Anhydride, CH3COO.CaH(CO2)O, m.p. 90°, which is also
formed when oxalacetic acid and acetylene dicarboxylic acid are acted on by
acetic anhydride at 100° (B. 28, 2511).
The hydroxymaleic anhydride, when treated with aniline at —20° and
acidified with 5N hydrochloric acid, is changed into Hydroxyma-leinanilic Acid,
CeH6NHCOC(OH):CHCOOH, m.p. 113° with decomposition, which is converted
by loN sulphuric acid into Hydroxyfumaranilic Acid, m.p, 140° with decomposi-
tion. The ethyl ester of Oxalacetanilic Acid, C8H5NHCOCH?CO.COaCaH5, the
third position isomer, is obtained from oxalic ester, acetanilide, and sodium
ethoxide. The anil acids are converted by acetyl chloride into hydroxymaleinanil
(and further intoAcetoxymaleinanil, CH3COO.C2H(CO)2NC6H6, m.p. 126°), which
easily loses water and forms the dimolecular Xanthoxalanil ; aniline produces
Anilinomaleinanil, CeHBNH.CaH(CO)NC6H6, m.p. 233° (see above) (B. 40,
2282).
Hydroxyfumaranilic acid and hydroxymalemanilic acid, which are fairly
stable alone, are decomposed even at o° by aniline into COa and pyroracemic
anilide (p. 409).
566 ORGANIC CHEMISTRY
Oxalacetic Ethyl Ester, C2H5OOC.COCH2COOC2H5 or C2H5OOC.-
C(OH):CH.COOC2H5, b.p.24 132°, and the methyl ester, m.p. 770°,
labile form, m.p. 87°, b.p.89 137° (A. 277, 375 ; B. 39, 256), are formed
from oxalic and acetic esters (p. 412) by means of sodium alconolate
(W. Wislicenus] ; also from acetylene dicarboxylic esters (p. 523) by
the addition of water by warming with sulphuric acid ; and from the
silver salt of oxalacetic acid and iodo-alkyls. When boiled with alkalis,
the ethyl ester undergoes " acid cleavage " into oxalic acid, acetic
acid, and alcohol ; when boiled with dilute sulphuric acid " ketone
cleavage " occurs into CO2 and pyroracemic acid, CH3.CO.C02H (p. 407).
When heated under ordinary pressure it suffers " carbon monoxide
cleavage " into CO and malonic ester, with pyroracemic ester as a by-
product (B. 28, 811) :
Hg Acid cleavage
CO2CaH6.CO.CH,TcOaCaH8j Ketone cleavage
COsCaH5Jc6|.CHICO8CaH6 Carbon monoxide cleavage
Reduction converts oxalacetic ester into the ester of i-malic acid
(B. 24, 3416).
Ferric chloride colours a solution of the ester a deep red. Copper
acetate precipitates the ethyl ester as a green copper salt (C8HnO5)2-
Cu-fH2O, m.p. 155°, anhydrous, m.p. 163°. If this salt is boiled with
methyl alcohol, it is converted into the copper salt of Oxalacetic Methyl
Ethyl Ester, COOCH3.COCH2COOC2H5, b.p.8 110° (A. 321, 372).
Ammonia becomes added on to oxalacetic ester, forming what is
probably the ammonium salt of the aci-oxalacetic ester (hydroxy-
fumaric or hydroxymaleic ester), CaHgOOC.qONHJlCH^OOCtH*
m.p. 83°. It becomes gradually changed into oxalocitric lactone ester,
which is also formed from oxalacetic ester and a tertiary amine (comp.
B. 39, 207).
Aminofumaric Ester, C2H5OCO.C(NH2):CH.CO2C2H5, b.p.20 142°,
is formed when the above ammonium salt is rapidly distilled ; also,
from chlorofumaric and chloromaleic ester and ammonia. Copper
acetate slowly regenerates the copper oxalacetate ester (A. 295, 344).
Aminofumaramide Ester, m.p. 139°, and Aminomaleic Amide Ester,
m.p. 119° (C. 1897,1.364).
Similarly to acetic ester, oxalic ester also condenses with aceto-
nitrile (B. 25, R. 175), and with acetanilide (see above) (B. 24,
1245).
unsym.-Diethoxysuccinic Ester, CO2C2H6.C(OC2H5)2CH2CO2C2H6, is formed
together with ethoxyfumaric ester (below) both from ordinary dibromosuccinic
ester and acetone dicarboxylic ester by the action of sodium ethoxide. The
resulting diethoxysuccinic acid, when allowed to stand under greatly reduced
pressure or when heated to 100°, loses ether and becomes converted into oxalacetic
acid (B. 29, 1792).
Ethoxyfumaric Ester, C2H5OOC.C(OC2H6) : CH.COOC2H6, b.p.n 130°, is
prepared from silver oxalacetic ester and iodoethane, and from dibromosuccinic
ester, with simultaneous formation of diethoxysuccinic ester (see above), by taking
up alcohol. The free Ethoxyfumaric Acid, m.p. 133°, is obtained from the ester
by the action of cold dilute alkali. Acetic anhydride converts it into the fluid
ethoxymaleic anhydride, which takes up water and forms Ethoxymaleic Acid, m.p.
OXALACETIC ESTERS 567
126*. Both acids are hydrolyzed by hydrochloric acid into oxalacetic acid (B. 28,
2512 ; 29, 1792).
Methyl Oxalacetic Ester, Oxalopropionic Ester, CO2C2H5.CO.CH(CH8).CO2-
C2HS, is formed from oxalic ester and propionic ester. Methyl Oxalacetanil,
CO.CO.CH(CH3)CONC8H8, m.p. 192°, is prepared from oxalic ester and pro-
pionanilide; also from anilinocitraconanil CO.C(NHCeH5):C(CHs)CONC6H6, the
product of action of chloro- or bromo-citraconanil (p. 516), aniline and sulphuric
acid (B. 24, 1256 ; 35, 1626).
Ethyloxalacetic Ester, Oxalobutyric Ester, CO2C2H6.CO.CH(C2H6)CO2C2Hg
(B. 20, 3394). Dimethyl Oxalacetic Ester, Oxalisobutyric Ester, CO2C2H5.CO
C(CH8)2CO2C2H8, b.p.u 117°, is obtained from oxalic ester, bromisobutyric ester,
and magnesium (B. 41, 964). Methyl Ethyl Oxalacetic Ester, b.p.14 134° (C. 1905,
1. 1590).
Nitrogen Derivatives of Oxalacetic Acid (B. 24, 1198). For the salt-like
addition products of oxalacetic anhydride and oxalacetic ester with pyridine and
ammonia, and their reaction products, see pp. 564, 565.
Oximes and Phenylhydrazones. a-Oximidosuccinic Acid, m.p. 143° with de-
composition, is formed from oxalacetic acid and hydroxylamine. Acetic anhydride
converts it into the fi-acid, m.p. 126° with decomposition (C. 1901, I. 353).
fi-Oximidosuccinic Monoethyl Ester, m.p. 54°, is prepared from the oxime of
oxalacetic ester and water ; and a-Oximidosuccinic Ethyl Ester, m.p. 107°, is
obtained from di-isonitroso-succinyl-succinic ester and water. When heated they
both yield CO2 and a-oximidopropionic ester, CH8C : N(OH)CO2C2H5. Both
monoesters are given the formula CO2H.CH2C : N(OH)CO2C2Hft, and are assumed
to be stereoisomers (B. 24, 1204). Oximidosuccinic ester, COaC2H5.C:N(OH).-
CH2CO2CaH5, is a colourless oil (B. 21, R. 351). Comp. Aspartic Acid and
Asparagine (pp. 553, 554).
Hydroxylamine and ammonia act on oxalacetic ester producing the ammonium
salt of isoxazolone hydroxamic acid, which is converted by alkalis into hydroxy-
furazan acetic acid,
O.N:C.CH,.CO /N:CCH2COOH
I ^O/ |
HON:C(OH) XN:C(QH)
which is oxidized by permanganate into hydroxyfurazan carboxylic acid (B. 28,
761).
Phenylhydrazine reacts with oxalacetic acid to form a phenylhydr ozone,
COOH.C(NNH.C8H5)CH8.COOH, m.p. 95°, with decomposition into CO2 and
pyroracemic acid phenylhydrazone. It undergoes the same decomposition when
boiled with water, but when heated with acids, it forms phenylpyrazolone car-
boxylic acid or lactazam (p. 406) (C. 1902, II. 189) :
COOH.C.CH. HaO COOH.C.CHa.COOH H2SO4 COOH.C.CHt.CO
II < II > II I
NNHC8H8 NNHCaH8 N N.C.H.
Phenylhydrazine becomes added to oxalacetic ester like ammonia (p. 566);
the addition product, m.p. 105°, is either a phenylhydrazine salt of hydrpxyfumaric
ester or is analogous to an aldehyde-ammonia compound. It readily changes
into Oxalacetic Ester Phenylhydrazone, m.p. 97°,which is also formed from acetylene
dicarboxylic ester and phenylhydrazine. The reaction products of hydrazine
and phenylhydrazine on oxalacetic acid also readily form lactazams or pyrazolone
derivatives by loss of alcohol (see above) (A. 246, 320 ; B. 25, 3442. '• 26» 1721).
Diazosuccinic Ester is formed when aspartic ester hydrochloride reacts with
sodium nitrite. It is yellow in colour, and is easily decomposed. When boiled
with water it forms fumaric ester ; reduction re-produces aspartic ester. Diazo-
succinamide Methyl Ester, CH8O2C.CN2.CH2CONH2, m.p. 81°, is formed, together
with fumaramide, from diazosuccinic methyl ester and ammonia (B. 19, 2460 ;
' Urea unites with oxalacetic ester to form Uracil Carboxylic Ester (i), m.p. 189°,
568 ORGANIC CHEMISTRY
*u<lD^oxalacetic Ester Carbamide (2), m.p. 104°; guanidine produces Dioxalacetic
Ester Guanidine (3), m.p. 147° with decomposition (C. 1898, 1. 445).
ROaC.C:CH.CO CH2COaR CH2CO2R
NH.CONH :> CO(N:C.COaR)2 HN:C(N:C.CO2R)2
2. Acetosuccinic Esters and Alkyl Acetosuccinic Esters are pro-
duced when sodium acetoacetic esters and their monoalkyl deriva-
tives are acted on by esters of the a-monohalogen fatty acids.
Acetosuccinic Ester, CH3CO.CHCO2C2H5
, b.p.14 141°, is prepared from
CH2.CO2C2H6
sodium acetoacetic ester and brom- or chloracetic ester. The hydrogen atom of
the CH- group, in the esters, can be replaced by alkyls, e.g., by methyl :
a-Methyl Acetosuccinic Ester, CH3COC(CH3)(CO2C2H6).CHaCO2C2HB, b.p.
263°, is formed from methyl acetoacetic ester and chloracetic ester.
fi-Methyl Acetosuccinic Ester, CH3CO.CH(CO2C2H6).CH(CH8)CO2CaH6, b.p.
263°, from acetoacetic ester and a-bromopropionic ester.
When heated alone the acetosuccinic acids act as in the aci- or enol- form,
lose alcohol and form define lactone carboxylic acids (C. 1898, I. 24). Ammonia
and the primary amines produce aminoethylidene succinic ester, which readily
changes into olefine-lactamic ester :
CH3CO.CH.C02R _ CH3C=C.C02R _ CH3C= = C.CO2R
CH2C02R NH2 CH2C02R NH.CO.CH2
Ammonia produces a.- A minoethylidine Succinic Ester, m.p. 72°, and A minoethylident
Succinimide, which is converted by hydrochloric acid into Acetosuccinimide,
m.p. 84-87° (A. 260, 137 ; B. 20, 3058 ; C. 1897, 1. 283) :
CH80=C — CCX CH3CO.CH— COV
| | \NH - > I >NH.
NH2 CHj.CCK CH2— CCK
Acid cleavage changes acetosuccinic acids into acetic and succinic or alkyl
succinic acids (pp. 492, 493). Ketone cleavage causes the formation of COaand
y-keto-acids (p. 421). Nitrous acid causes acetosuccinic ester to lose alcohol and
CO2, and to change into isonitrosolcevulinic acid (p. 547) (comp. Isonitrosoacetone,
P. 354)-
COaC2H5 HN02
C02H.CH2.C : (NOH).CO.CHt.
KETOGLUTARIC ACID GROUP
1. a-Ketoglutaric Acid, COOH.CH2CH2.CO.COOH, m.p. 113°, is obtained
from oxalosuccinic ester by ketone cleavage (C. 1908, II. 786). Cyanoximidobutyric
Acid, CO2H.CH2.CH2.C = (NOH)CN, m.p. 87°, is a derivative of a-ketoglutaric
acid. It is formed when cold sodium hydroxide acts on furazan propionic acid
(p. 546). When it is boiled with sodium hydroxide a-Oximidoglutaric Acid,
CO2H.CHa.CH2C=N(OH)CO2H, m.p. 152°, is produced (A. 260, 106).
2. Acetone-Dicarboxylic Acid, fi-Ketoglutaric Acid, CO(CH2C02H)2,
m.p. about 130°, and decomposes into CO2 and acetone. It may be
obtained by warming citric acid with concentrated sulphuric acid (v.
Pechmann, B. 17, 2542 ; 18, R. 468 ; A. 278, 63), and by oxidizing
it with permanganate (C. 1900, I. 328), The diethyl ester may be-
prepared by the action of alcoholic hydrochloric acid on y-cyanaceto-
acetic ester.
Acetone dicarboxylic acid dissolves readily in water and ether. The
alteration which takes place on heating the acid alone (see above),
also occurs on boiling it with water, acids, or alkalis. The solutions
KETOGLUTARIC ACID GROUP 569
of the acid are coloured violet by ferric chloride. Hydrogen reduces
the acid to /Miydroxyglutaric acid (p. 558).
PC15 converts the acid into j3-chloroglutaconic acid, CO2H.CH : CCl.CHjCOjH.
Hydroxylamine changes it to Oximidoacetone Dicarboxylic Acid, CO2H.CH2.-
C(NOH)CH2CO2H+H2O, m.p. 54°, anhydrous, m.p. 89° (B. 23, 3762). Nitrous
acid converts acetone dicarboxylic acid into diisonitroso-acetone (p. 537) and
CO2 (B. 19, 2466 ; 21, 2998). The acid is condensed by acetic anhydride to
CH3.CO.CH.CO.C.CO2H
dehydracetocarboxylic acid, \\ (A. 273, 186).
CO-O-CCH,
Acetone Dicarboxylic Ester, RO2C.CH2COCH2.CO2R ; methyl ester, b.p.12 128° ;
ethyl ester, b.p.12 138° (B. 23, 3762 ; 24, 4095 ; C. 1906, II. 1395)- Acid and
alkaline reagents cause the esters to lose alcohol and water, and readily to condense
R02C.CH2.C:C(COaR)x
to orcinol upfi-tricarboxylic ester, RO2C.C/ ^COH (Vol. II.).
^
Sodium, and iodo-alkyls produce alkyl acetone dicarboxylic esters, whereby
the hydrogen atoms of the two CH2-groups can be successively replaced by alkyl
groups (B. 18, 2289) ; it is, however, difficult to separate completely the various
products of the reaction. aa^-Dimethyl Acetone Dicarboxylic Ester, CH8CH(CO2R)-
COCH(CO2R)CH3, is condensed by concentrated sulphuric acid into aci-dimethyl-
CH3C— CO
cyclobutanone carboxylic ester, , a monobasic acid (B. 40,
HOC— C(CH3)C92R
1604), of which the sodium salt reacts with iodomethane in alcohol to form
trimethyl acetone dicarboxylic ester. This is also formed from aa-diethyl acetone
dicarboxylic ester, (CH3)aC(CO2R).COCH2CO2R, the product of reaction of
dimethyl malonic ester, acetic ester, and sodium (C. 1903, I. 76 ; II. 190).
aa-Diethyl Acetone Dicarboxylic Ester, CO2C2H5.C(C2H5)2COCHaCO2C2H8, is
formed by the carbon monoxide cleavage of a-diethyl y-oxalyl acetoacetic ester,
C2H5O?C.C(C2H?)2COCH2COCO2C2H5 (comp. pp. 567, 609) (B. 33, 3438).
Iodine and di-sodium acetone dicarboxylic ester produce hydroquinone tetra-
carboxylic ester (Vol. II.).
Condensation of acetone dicarboxylic ester and aldehydes (B. 29, 994 ; R. 93;
41, 1692, etc.).
O-Ethyl Acetone Dicarboxylic Ester, fi-Ethoxyglutaconic Ester, C2H6O?C.CH :-
C(OC2H6).CH2CO2C2H5, b.p.n 146°, is formed from acetone dicarboxylic ester,
orthoformic ester, and acetyl chloride. Hydrolysis produces at first the free
fi-Ethoxyglutaconic acid, m.p. 182° (C. 1898, II. 414).
Aqueous ammonia converts the ester into fi-Hydroxyaminoglutaminic Ester,
RO2C.CH2C(OH)(NH2).CH2CONH2, and then Glutazine, fi-Aminoglutaconimide.
I |
CO.CH : C(NH2).CH2CONH, m.p. 300° with decomposition. This substance is
converted by alcoholic ammonia into fi-Aminoglutaconic Ester, RO2C.CH : (NH2)-
CH2CO2R (B. 23, 3762). Aniline at ordinary temperatures produces Anilacetone
Dicarboxylic Ester, C8H5N : C(CH2CO2R)2, m.p. 98° ; whilst at 100° Acetone Di-
carboxylic Anilide, OC(CH2CONHC6H5)2, is formed, together with other sub-
stances (B. 33, 3442 ; 35, 2081).
Nitrous acid converts acetone dicarboxylic esters into I sonitrosoacetone
Dicarboxylic Ester (i) and Hydroxyisoxazole Carboxylic Ester (2) (B. 24, 857) ;
fuming nitric acid produces a Di-isonitroso-Peroxide (3) (B. 26, 997) :
RO2C.C.COCH2.CO2R ROZ.C.C.C(OH) : C.COaR
(i) II (2) II I
NOH N - O
ROaC.C-CO-C.C02R
(3) looJ
The phenylhydrazone of acetone dicarboxylic acid, like the ester, readily forms
bhe corresponding lactazam (phenylpyrazolone acetic acid) (B. 24, 3253) :
C6H6NHN : C.CH2CO2H _ C6H6N.N : CCH,CO,H
HOOC.CH. CO— CH,
570
ORGANIC CHEMISTRY
y-Cyanacetoacetic Ester, CN.CHaCO.CHaCOaC2H5, b.p.40 135°, is formed from
y-chloracetoacetic ester and potassium cyanide (B. 24, R. 18, 38). y-Cyano-
dimethyl-acetoacetic Ester, CN.CH2CO.C(CH3)2.CO2CH3, is formed from y-bromo-
dimethvl-acetoacetic ester. When heated with alkalis or acids it passes into
COaH.CH.CH(OH).C(CH3)a
aa-Dimethylfiy-Dihydroxy glutaric Acid Lactone, \ \ , m.p.
214° (B. 32, 137), which, on reduction, is converted into y-hydroxy-dimethyl-
glutaric acid lactone (p. 559).
3. a- A cetyl n.-Glutaric Acids are prepared by the action of j8-iodopropionic
ester on the sodium compounds of acetoacetic ester and the alkyl acetoacetic
esters : a-Acetoglutaric Ester, ROaC.CH(COCH8)CHa.CHa.COaR, b.p. 272° ;
a-Ethyl a-Acetoglutaric Ester, RO2C.C(CaH6)(COCH3).CH2CHaCO2R, decomposes
on distillation. On loss of COa, the free acids pass into the corresponding 8-keto-
carboxylic acids (p. 424) (A. 268, 113). With ammonia and primary amines they
form lactams of B-amino-olefine dicarboxylic mono-esters (B. 24, R. 660).
4. fi-Acyl Glutaric Esters are formed when the sodium salt of tricarballylic
acid (p. 593) is heated with carboxylic anhydrides, with simultaneous loss of CO2 ;
they are, however, converted at the temperature of reaction into dilactones,
from which the ketone dicarboxylic acids are regenerated by the action of alkalis
(Fittig, A. 341, i) : ______
/CHjCOOH (RCO)20 /CH2COO /CHaCOOH
HOOC.CH/ > RC.CH/ < > RCO.CH<
xCHaCOOH xCHaCOO \:HaCOOH
Tricarballylic Acid. DUactone. 0-Acyl Glutaric Acid.
fi-Acetyl Glutaric Acid, CH3CO.CH(CH2COOH)2, m.p. 58°, is obtained from
its dilactone, m.p. 99°, b.p.ia 205°, by the action of boiling water or alkalis. The
dilactone is formed when sodium tricarballylate is heated with acetic anhydride
at 120-130°, also when acetotricarballylic ester is boiled with hydrochloric acid
(A. 295, 94).
fi-Butyryl- and fi-Isobutyryl-glutaric Acid, CH3CH2CH3COCH(CH2COOH)2,
m.p. 88°, and (CH3)2CHCOCH(CH2COOH)2, m.p. 100° with decomposition;
dilactones, m.ps. 55° and 90°, ajre obtained from sodium tricarballylate and butyric
or isobutyric anhydrides.
Keto-adipic, Ketopimelic and the Higher Ketone-diearboxylie Oxides.
1 . Oximes of a-Keto-adipic A cid and a- Ketopimelic A cid are obtained from
adipic and pimelic esters by means of their carboxylic condensation products
(comp. p. 504) when acted on by ethyl nitrite and sodium alcoholate :
CHa.CH(COaR)v HN°2 CHa.C(NOH)COaR
| >CO > |
GHa CH/ R.OH CH2.CHa.C02R.
o.'0ximido-adipic Ester, m.p. 53°; acid, HOaC.CH2CH2CH2C(NOH)COaH,
m.p. 152° with decomposition into CO2,H2O, and glutaric acid nitrile (p. 502).
a.-Oximido-y-methyl-adipic Ester, m.p. 50° ; acid, HOOC.CH2CH(CH3).CH2-
C(NOH)CO2H, m.p. 163° with decomposition into CO2, H2O, and 0-methyl
glutaric acid nitrile (p. 503). a-Oximidopimelic Ester, on oil ; acid, HOOC[CH2]4-
C(NOH)CO2H, m.p. 143° with decomposition into COa, HaO, and adipic acid
nitrile (p. 505) (B. 33, 579).
2. Acetone Diaeetic Acid, Hydrochelidonic Acid, Lavulinic Acetic Acid, y-Keto-
pimelic Acid, CO(CHaCHaCOaH)2, m.p. 143°, is formed from chelidonic acic
(or acetone dioxalic acid, p. 621) by reduction; also from furfuracrylic acid
(Vol. II.) by cleavage with hydrochloric acid. Treatment with acetyl chloride
or acetic anhydride converts it into a dilactone, m.p. 75°, which when boiled with
water or alkalis re-forms the acid :
<aCH2CO2H I /CH2CH2COO
•< > C<
,CHaCOaH | \CHaCHaCOO
DI-OLEFINE-KETONE DICARBOXYLIC ACIDS 571
This dilactone is also formed during the prolonged boiling of succinic acid :
2C4HflO4==C7H8O4+CO2+2H2O (B. 24, 143 ; A. 267, 48 ; 294, 165). Hydroxyl-
amine produces the oxime, C(NOH)(C2H4.CO2H)2, m.p. 129° with decomposition ;
phenylhydrazine gives rise to the phcnylhydrazone, C(N2H.C,H6)(C2H4CO2H),
m.p. 107°. The Acetone Diacetic Ester (ethyl ester, b.p.18 171°) gives, with bromine,
sym.-dibromacetone diacetic ester ; methyl ester, m.p. 58° ; ethyl ester, m.p.
49° (B. 37, 3295).
Phoronic Acid, Acetone Tetramethyl Diacetic Acid, CO[CHa.C(CH3)aCO2H]2,
m.p. 184°, is formed from the addition product of phorone and two molecules of
hydrochloric acid (p. 229) by successive treatments with potassium cyanide and
hydrochloric acid (B. 26, 1173). The corresponding y-dilactone, m.p. 143°
(A. 247, no).
3. Acetone Di-fi-propionic Acid, 8-Keto-azelaic Acid, CO[CHaCHaCH2CO2H]2,
m.p. 102° (dimethyl ester, m.p. 31°), is obtained from acetone dipropionic dicar-
boxylic ester, the product of di-sodium acetone dicarboxylic ester and two
molecules of /J-iodopropionic acid. Reduction changes it into sym.-hydroxy-
azelaic acid, HOCH[CH2CH2CH2CO2H]2, m.p. 105°. When heated it gives off
water, but instead of a dilactone (p. 570) a hexamethylene ring body is formed :
Dihydroresorcyl Propionic Acid, CO[CH2]3COCH[CH2]2CO2H. This, on cleavage
with nitrous acid (comp. p. 570), yields oximido-acetone dipropionic acid,
HOaC[CH2]3COC(NOH)[CH2]2CO2H, which undergoes the Beckmann inversion
(p. 227), and is decomposed into glutaric and succinic acids (B. 37, 3816).
OLEFINE- AND DI-OLEFINE-KETONE DICARBOXYLIC ACIDS
1. Oxalocrotonic Acid, COOH.CO.CH2CH : CH.CO2H, m.p. 190°, with for-
mation of a di-olefme-lactone carboxylic acid, a-Pyrone ^-Carboxylic Acid,
CO2H.C: CH.CH : CHCOO, m.p. 228°, is prepared from Oxalocrotonic Ester,
C2H5O2C.CO.CH2CH : CHCO2R, m.p. 79°, which is formed by condensation of
oxalic and crotonic esters by sodium alcoholate. Like oxalacetic ester, it
possesses strong acidic properties (comp. Glutaconic Ester, p. 521) (C. 1901, II.
1264).
2. a-Aceto-p-methyl-ghitaconic Acid, CH3CO.CH(CO2H)C(CH3) : CHCOaH, is
the hypothetical acid of which the lactone of the act-form isIsodehydraceticAcid,
Dimethyl Coumalic Acid, CH3C : C(CO2H).C(CH3) : CHCO, m.p. 155°. . This is
obtained by condensation of acetoacetic ester by means of sulphuric acid ; also
by reaction of sodium acetoacetic ester with jS-chlorocrotonic ester. The
lactone decomposes at 205° into COa and mesitene lactone (p. 399). Methyl
ester, m.p. 67°, b.p.14 167° ; ethyl ester, m.p. 25°, b.p.12 166°, takes up two molecules
of ammonia to form a salt which resembles ammonium carbonate in its decom-
position products ; at 100-140°, however, there is formed the corresponding
lactam, Carboxethyl Pseudolutidostyril, CH8C: C(COaR)C(CHs):CHCONH, which
is also formed by condensation of j8-aminocrotonic ester (p. 419) (A. 259, 172;
B. 30, 483).
3. fi-Carboxyl Diacrylic Acid, s-Keto-^-pentadiene Dicarboxylic Acid, CO[CH :-
CHCOOH] 2, m.p. above 230°, with decomposition. Its esters are yellow-coloured ;
dimethyl ester, yellow leaflets, m.p. 169°, diethyl ester, yellow prisms, 50°, are
formed from dibromacetone diacetic esters (above) by the loss of 2 molecules
of hydrobromic acid through quinoline (B. 37, 3293).
Carboxyl Dimethyl Acrylic Acid, Acetone Dipyroracemic Acid is precipitated
: C(CHj).COO
from its salts in the form of its anhydride or y-dilactone, C< t
'. C(CIi3).COO
i
m.p. 1 66°, b.p. 234°, which is obtained by the condensation of acetone and pyro-
racemic acid (B. 31, 681).
572 ORGANIC CHEMISTRY
THE URIC ACID GROUP
Uric acid is a compound of two cyclic urea residues combined with
HN— CO
a nucleus of three carbon atoms : OC C— NH- By its oxida-
">CO.
HN— C— NH/
tion the ureUes of two dicarboxylic acids — oxalic acid and mesoxalic
acid — were made known. The ureide of a dicarboxylic acid is a
compound of an acid radical with the residue, NH.CO.NH ; e.g.
\co=ureide of oxalic acid, oxalyl urea, parabanic acid.
CO— NH/
They are closely related to the imides of dibasic acids, succinimide
(p. 497 jf, and phthalimide ; and parabanic acid may, for example, be
regarded as a mixed cyclic imide of oxalic and carbonic acids. Like
the imides, they possess the nature of an acid, and form salts by the
replacement of the imide hydrogen with metals. The imides of dibasic
acids are converted by alkalis and alkaline earths into amino-acid
salts, which lose ammonia and become converted into salts of dibasic
acids. Under similar conditions the ureide ring is ruptured. At first
a so-called wr-acid is produced, which finally breaks down into its
components, urea and a dibasic acid :
CH2COX CH.CONH. > CHaCOOH
| >NH > | -f NH,
CH2CCK CHjCOOH CH2COOH
Succinimide. Succinamic Acid. Succinic Acid.
CONHX CONHCO COOH NHav
I >co > i > I + >co.
CONH/ COjHNH, COOH NH/
Parabanic Oxaluric Oxalic Urea.
Acid. Acid. Acid.
The names of a series of urei'des having an acid character end in
" uric acid," — e.g. barbituric acid, violuric acid, dilituric acid. These
names were constructed before the definition of the ur-acids given
above, and it would be better to abandon them and use the ureide
names exclusively, — e.g. malonyl urea, oximidomesoxalyl urea, nitro-
malonyl urea, etc.
It is the purpose to discuss the urea derivatives of aldehyde- and
keto-carboxylic acids, of glyoxalic acid and acetoacetic acid in con-
nection with the ure'ides and " ur " acids of the dicarboxylic acids.
These are allantom and methyl uracil. The first can also be prepared
from uric acid, whilst the methyl uracil constitutes the parent sub-
stance for the synthesis of uric acid.
Xanthine, theobromine, theophylline, theine or caffeine, and
guanine, hypoxanthine, adenine, etc., are related to uric acid.
Urei'des or Carbamides of Aldehyde- and Keto-monocarboxylic
Acids.
These bodies are connected themselves with the ureides of the
oxyacids, hydantoin, and hydantoic acid, which have already been
discussed (p. 442).
ALLANTOIN 573
The following compounds with urea are derived from glyoxylic acid :
OCH.CO.NHCONHa HOCH.CO.NH.CONH
v -v -/
Allanturic Acid or Glyoxalyl Urea.
(NH2CONH)2CHCOOH NH2CONH.CHCO.NHCONH
Allantoic Acid and Allantom.
Allantoin, C4H?O3, m.p. 231° with decomposition, is present in the urine
of sucking calves, in the allantoic liquid of cows, and in human urine after the
ingestion of tannic acid. It has also been detected in beet-juice (B. 29, 2652).
It is produced artificially on heating glyoxalic acid (also mesoxalic acid,
CO(CO2H)2) with urea to 100° ; also from hydanto'in by the action of bromine
and urea (A. 332, 134).
Allantom is formed by oxidizing uric acid with PbO, and MnOa, potassium
ferricyanide, or with alkaline KMnO4 (B. 7, 227). Methylated uric acids when
oxidized in alkaline solutions yield methyl allantoins (comp. p. 583) (A. 323, 185).
Allantoin crystallizes in glistening prisms, which are slightly soluble in cold
water, but readily in hot water and in alcohol. It has a neutral reaction, but
dissolves in alkalis, forming salts.
Sodium amalgam converts allantoin into glycoluril, or acetylene urea.
Allantoic Acid (formula, see above) decomposes at 165°, is prepared by
hydrolysis of allantoin or its salts. It is not very soluble in water, and readily
decomposes into urea and glyoxylic acid. Ethyl ester, (NH2CONH)2CHCOa-
C2H6, is prepared from glyoxylic ester, urea, and hydrochloric acid. Ammonia
or alkali hydroxide solutions condense it to allantoin (C. 1904, I. 792 ; 1906, II.
Allanturic Acid (formula, above) is obtained when allantom is warmed with
nitric acid, and by the oxidation of hydantoin (p. 442). It is a deliquescent
amorphous mass, insoluble in alcohol. Glyoxyl Urea (formula, see above) is a
decomposition product of oxonic acid, C4H6N3O, obtained by oxidation of uric
acid. It consists of thick needles, readily soluble in hot water (A. 175, 234).
Glyoxylic acid unites with guanidine to form, according to the conditions of
reaction, guanidine glyoxylic acid (i), m.p. 210° with decomposition, or imido-
allantoin (2) (?) (A. 315, i); but with thiourea it forms glyoxyl thiocarbimide (3),
consisting of red-brown crystals (A. 317, 151) :
/NH— CHOH /NH— CH.NKL /NHCO
(i) HNC< (2) HNC< >CO (3)
\NH8 COOH \NHa CO.NHK
Pyruvil, NH2CONH.C(CH3)CO.NHCONH, is formed by heating pyroracemic
acid and urea, during which an intermediate product, CH3C(NHCONH2)2COOH,
is formed (C. 1901, II. 1114).
The uracils are the ureides of jS-aldo- and jS-keto-carboxylic acids. The simplest
uracil, the ure'ide of formyl acetic acid, its amino-derivative cytosine, like thymine,
the uride of a-formyl propionic acid, together with various purine derivatives
(p. 587), are members of the nucleinic acids (see Proteins) which occur in thymus
glands, fish spermatozoa, yeast, kernels of plants, etc., and obtained from these by
hydrolysis with sulphuric acid. The uracils contain the six-membered pyrimidine
ring (Vol. II.), which, when united to the five-membered glyoxaline ring, shows
the constitutional formula of uric acid (q.v.). Derivatives of uracil are, there-
fore, employed in many ways for the synthesis of uric acid and other purine
derivatives (pp. 585, et seq).
(6) (0
Uracil, C4H402N8. (3) CH<— NH>CO(2) or
~
(4) (3)
Dihydroxypyrimidine, m.p. 335° with decomposition, It is prepared from
574 ORGANIC CHEMISTRY
nuclemic acid (p. 573), and synthesized (i) from hydrouracil (p. 444) by
bromination to bromhydrouracil, C4H6BrO2N2, and withdrawal of hydrobromic
acid by means of pyridine ; (2) Trichloropyrimidine, C4HC13N2, obtained from
barbituric acid (p. 576), and POC18, reacts with sodium methoxide to form
dimethoxychloropyrimidine, (C4H(OCH8)2C1N, ; this is reduced with zinc dust
and hydrochloric acid to 2,6-dimethoxypyrimidine, C4Ha(OCH3)2Na, which is
hydrolyzed to uracil by evaporation with hydrochloric acids; (3) 0-Methyl
thiourea and formyl acetic ester produce methyl mercapto-oxypyrimidine
(comp. p. 453), which is decomposed by hydrochloric acid into methyl mercaptan
and uracil (B. 34, 3751 ; 38, 3379 ; C. 1903, I. I3°9)- Uracil is easily soluble in
hot water, and with difficulty in alcohol and ether. It is precipitated by phospho-
tungstic acid and mercuric sulphate.
Cytosine, Uracilimide, 2-Oxy-6-amino-pyrimidine, C4H6ON3 (see below),
decomposed at 320-325°, is synthesized as follows : ethyl mercapto-oxypyri-
midine (p. 573) and PC15 give ethyl mercaptochloropyrimidine, which, by
ammonia, is converted into ethyl mercapto-aminopyrimidine ; this is decom-
posed by hydrobromic acid into mercaptan and cytosine (C. 1903, I. 1309).
Nitrous acid converts cytosine into uracil (C. 1903, I. 1365) :
,N«=CC1 NH, ,N==C.NH2
8 : C«HS.C/ | >
^N.CH : CH
/N— -C.NH, HNO, /NH CO
oc/ i > oo( i
\NH.CH : CH XNHCH : CH
Cytosine. Uradl.
Cytosine is decomposed by permanganate into biuret (p. 445) and oxalic acid.
It forms salts with nitric acid, sulphuric acid, H2PtCla ; also with silver, mercury,
etc. : 4>icrate, m.p. 278°. The isomeric 2-Amino-6-oxypyrimidine, theguaneide of
/NH CO
formyl acetic acid, NHaC< | ,m.p. 276° with decomposition, is formed
\NHCH : CH
from guanidine and formyl acetic ester.
Thymlne, s-Methyl Uracil, CH8C<^CH'NHyCO, m.p. 318-321* with decom-
position, is synthesized analogously to the uracils : (i) from 5-methyl hydro-
uracil (p. 444) ; (2) from C-methyl barbituric acid (p. 577) ; (3) from 2-methyl-
mercapto-5-methyl-6-oxypyrimidine, the product of 0-methyl thiourea and
a-fonnyl propionic ester (B. 34, 3751 ; 38, 3394 ; C. 1903, I. 1309).
QQ NH
4-Methyl Uracil, CH<r,rTT x xrH*>CO, m-P' 320* w^^ decomposition, is
synthesized: (i) from acetoacetic ester and urea and (2) from 4-methyl hydro-
uracil (p. 444) ; POC18 reacts with methyl uracil and produces ^-methy 1-2,6-
dichlor o-pyrimidine ; electrolytic reduction yields methyl trimethylene urea
(p. 441) and i, 3-diamino butane. Nitric acid and PaO6 give 5-nitro-4-methyl-
uracil, and this on reduction forms amino-methyl-uracil (p. 585). Permanganate
produces $-oxy-methyl-uracil and then 4,5,5-trioxy-methyl-hydrouracil (methyl
isodialuric acid) . The latter, by further action of permanganate, is broken
up into acetoxaluric acid ; but alkalis produce acetyl glyoxyl urea (the ureide
of a/2-diketobutyric acid) which, with chromic acid, yields parabanic acid
(P- 575).
NHCOCH NH.CO.COH NH.CO.C(OH)S
KNH.CCH, CO.NHCOCH3 / I CO.NH.C(OH)CH,
NH.CO, NH.CO.COH * NH.OXCOOH
I >co •< /I I
CO.NH/ CO. NHCOCH, CO.NH.COOH,
CARBAMIDES OF DICARBOXYLIC ACIDS 575
This series of oxidations and transformations probably represents the alkaline
oxidation reactions of uric acid and its derivatives (comp. scheme, p. 583, and
A. 333, 144).
Methylation of 4-methyl uracil by means of KOH and iodomethane
produces ^, ^-dimethyl uracil, m.p. 22°, I, ^-dimethyl uracil, m.p. 262°, and
1,3,4-trimethyl uracil, m.p. 111° (A. 343, 133, etc.).
Further uracil derivatives are obtained as intermediate compounds during
the synthesis of uric acid (pp. 585, 586).
UREIDES OR CARBAMIDES OF DICARBOXYLIC ACIDS
The most important members of this class are parabanic acid and
alloxan. They were first obtained by oxidizing uric acid with nitric
acid. These cyclic urei'des by moderated action of alkalis or alkali
earths are hydrolyzed and become " ur "-acids. When the action of
the alkalis is energetic, the products are urea and dicarboxylic acids
—e.g. :
CO— NHv H20 C02H NH2V H2o CO2H NH
\CO —^ I >CO —> I +
O— NEK Ba(OH)2 CO NH/ (KOH) CQ R NH
Oxalyl Urea Oxaluric Oxalic Carbamide.
Parabanic Acid. Acid. Acid. Urea.
/NH.CO
Oxalyl Urea, Parabanic Acid, co< I , m.p. 243° with decom-
NNH.CO
position, is produced by the oxidation of uric acid and alloxan with
ordinary nitric acid (A. 182, 74) ; by the treatment of hydantom
(p. 442) with bromine and water (A. 333, 115) ; and, synthetically, by
the action of POC13 on a mixture of urea and oxalic acid ; or by
heating oxamide and diphenyl carbonate CO(OC6H5)2 together at
240° (C. 1900, I. 107). It is soluble in water and alcohol, but not in
ether.
Its salts are easily converted by water into oxalurates ; silver salt, C3N2O8Ag2,
is obtained as a crystalline precipitate.
Oxalyl Methyl Urea, Methyl Parabanic Acid, C3H(CH3)N2O3, m.p. 149-5°, is
formed by boiling methyl uric acid, or methyl alloxan, with nitric acid, or by
treating theobromine with chromic acid mixture. It is soluble in ether.
Oxalyl Dimethyl Urea, Dimethyl Parabanic Acid, Cholestrophane, C3(CH3)2-
N2O8, m.p. 145°, b.p. 276°, is obtained from dimethyl alloxan and theine by
oxidation, or by heating methyl iodide with silver parabanate.
Oxaluric Acid, NH2CO.NHCO.CO2H, results from the action of alkali
L parabanic acid. Free oxaluric acid is a crystalline powder,
dissolving with difficulty. When boiled with alkalis or water, it
lecomposes into urea and oxalic acid ; heated to 200° with POC13,
t is again changed into parabanic acid.
The ammonium salt, C3H8N2O4NH4, and the silver salt, C,H8N2O4Ag, crystal-
ize in glistening needles.
The ethyl ester, C8H8(C2H6)N2O4, m.p. 177°, is formed by the action of ethyl
odide on the silver salt, and has been synthetically prepared by allowing ethyl
>xalyl chloride to act on urea.
Oxaluramide, Oxalan, NH2OO.NHCOCONH2, is produced on heating ethyl
ixalurate with ajmnoaia, and by fusing urea with ethyl oxamate.
576 ORGANIC CHEMISTRY
xNHCO
Oxalyl Guanidine, HNrCX' | , is formed from oxalic ester and guanidine
(B. 26, 2552 ; 27, R. 164). NHCO
(i) (6)
Malonyl Urea, Barbituric Acid, (*) CO<>CH, (5), is obtained from
alloxantin by heating it with concentrated sulphuric acid, and from dibromo-
barbituric acid by the action of sodium amalgam. It may be synthetically
obtained by heating malonic acid and urea to 100° with POC1S, or by boiling
urea and sodium malonic ester together in alcoholic solution (B. 37, 3657). It
crystallizes with two molecules of water in large prisms from a hot solution, and
when boiled with alkalis is decomposed into malonic acid and urea. Electrolytic
reduction converts it into hydrouracil and trimethylene urea (pp. 441, 444).
The hydrogen of CHa in malonyl urea, as in malonic ester, can be readily
replaced by bromine, NO2, and the isonitroso-group. It forms metallic salts (B.
14,1643; 15,2846).
When silver nitrate is added to an ainmoniacal solution of barbituric acid, a
white silver salt, C4HaAgaNaO3, is precipitated.
Malonyl Dimethyl Urea, i.^-Dimethyl Barbituric Acid, CH2[CON(CH3)]2CO,
m.p. 123°, and Malonyl Diethyl Urea, m.p. 52°, are formed from malonic acid,
POC13, and the respective di-alkyl urea (B. 27, 3084 ; 30, 1815).
6-Imino-isobarbituric Acid, ^-Aminouracil, CHa<lNH>CO' is ob~
tained in the form of needles which, when heated, form cyanacetic ester,
sodium ethoxide, and urea. During the reaction cyanacetyl urea, CN.CH2CO.-
NHCONHa, is formed as an intermediate product, which can also be prepared
from cyanacetic acid, urea, and POC18 or (CH3CO)2O. 6-Imino-2-thio-barbituric
Acid, CHa[CaO(NH)](NHa)CS, is produced from cyanacetic ester and thiourea ;
guanidine and this latter body form 6,2-Diiminobarbituric Acid, CHa(aCaONH)-
(NH)aC : NH. These substances are decomposed by dilute acids into ammonia,
barbituric acid, and 2-Thiobarbituric Acid, Malonyl Thiourea, CHa(CONH)2CS,
&nd2'IminobarbituricAcid,MalonylGuanidine, CH2(CONH)aC: NH, respectively.
These compounds are directly produced from malonic ester and thiourea or
guanidine (A. 340, 312 ; B. 26, 2553). 2,4,6-Triiminobarbituric Acid, 2,4,6-
Triaminopyrimidine, CHa[C(NH).NH]tC : NH, is formed from malonic nitrile
and guanidine (B. 37, 4545). 4,4,6-Trichloropyrimidine, CH<(C.C1.N)2>CC1,
b.p. 213°, is formed from barbituric acid and POC18 at 130-145° (B. 37, 3657).
It can be converted into uracil (p. 573).
C-Alkylated Barbituric Acids.
These compounds have been minutely studied on account of some
of their number acting as valuble saporifics, e.g. C-diethyl barbituric
acid (Veronal) and C-dipropyl barbituric acid.
Methods of formation.
(1) Alkylation (by the action of iodomethane on the silver salt of barbituric
acid) only produces directly C-dimethyl barbituric acid.
(2) Malonyl guanidine (see above) is more conveniently alkylated, and the
mono- and di-alkyl malonyl guanidines which are produced are converted into
mono- and di-alkyl malonyl ureas when heated with acid (C. 1906, II. 1465).
(3) Condensation may occur between monomalonyl chloride (or, better,
the malonic ester), monocyanacetic ester or mono-alkyl malononitrile with
urea, thiourea, guanidine, or dicyandiamide, with or without the help of sodium
alcoholate ; C-mono-alkyl barbituric acid or its thio- and imino-derivatives (see
above) are formed, which, on hydrolysis, yield the barbituric acids. The di-
alkyl compounds produce the respective barbituric acid (A. 335, 334 ; 340,
310 ; 359, 145 ; C. 1906, I. 514 ; II. 1465 ; 1695, etc.) :
NITROMALONYL UREA 577
(4) Dialkyl Malonuric Acids, such as Diethyl Malonuric Acids, HOOC.C-
(CaH|)a.CO.NHCONHa, m.p. 162°. with decomposition ; Dipropyl Malonuric Acid,
m.p. 147° with decomposition, are formed from the malonic acid, urea, and
fuming sulphuric acid. They readily decompose into COa and dimethyl aceto-
urea; the nitriles, on the other hand, such as NC.C(CaH,)a.CO.NHCONHa
(which is produced from alkyl cyanacetic ester, NaOR, and urea at ordinary
temperatures) easily condense to cyclic compounds. Similarly, Diethyl Malonyl
Urethane, (CaH,)aC(CONHCOOC2H,)a, is formed from diethyl malonyl chloride
and two molecules of urethane ; it is readily converted into diethyl barbituric
acid by CaH,.ONa (C. 1906, II. 574).
C-Monomethyl Barbituric Acid, CH3CH(CONH)aCO. m.p. 203° (B. 38, 3394).
C-Ethyl Barbituric Acid, m.p. 190°, unlike barbituric acid itself, is easily ethylated
by iodoethane and alkalis to veronal. C-Propyl Barbituric Acid, m.p. 208°.
C'Isopropyl Barbituric Acid, m.p. 216°.
C-Dimethy I Barbituric Acid, (CH,),C(CONH),CO, m.p. 279°, is also obtained
from dimethyl malonic acid, urea, and POC1, ; but if this treatment be applied
to the homologues, only di-alkyl acetoureas, RaCHCO.NHCONHa, are pro-
duced. These acids yield stable di-sodium salts, whilst the homologous di-
alkyl barbituric acids only give easily Hydrolyzed mono-sodium salts.
C-Diethyl Barbituric Acid, Veronal, (C.HO.CfCONHJ.CO, m.p. 212°. has a
bitter taste, and acts as a soporific. It crystallizes from hot water in the form
of colourless spear-shape crystals, and is easily soluble in alkalis and ammonia.
Thioveronal, Diethyl Malonyl Thiourea, (CaH,)tC(CONH)aCS, m.p. 180°, when
heated with aniline and phenylhydrazine exchanges S for the groups :NC6H6
and NNHC6HB. Reduction with sodium amalgam produces di-ethyl malon-
amide, (CtH8),C(CONH,)^D»>/Ay/ Malonyl Methylene Diatninc or Desoxy veronal.
(CjHaJaCtCONHJjCH,, m.p. 293°, and other substances (A. 359, 154).
Tartronyl Urea, Dialuric Acid, CO <£[**£§> CH-OH» is formed by the re-
duction of mesoxalyl urea (alloxan) with ammonium sulphide or with zinc
and hydrochloric acid, and from dibromobarbituric acid by the action of hydrogen
sulphide. On adding hydrocyanic acid and potassium carbonate to an aqueous
solution of alloxan, potassium dialurate separates but potassium oxalurate
remains dissolved :
Potassium Dialurate. Potassium Oxalurate.
Isodialuric Acid, isomeric with dialuric acid, is prepared from oxyuracil
(p. 585) and bromine water ; bases easily convert it into dialuric acid,
C0^NH.C1 (CHk CQ _ ^ CO<rNH'CCScHOH
*-Aj\^JJ £Q _ ^>UU 7" *•*•' Xj^H .CO^
Isodialuric acid is differentiated from dialuric acid by its more ready oxidation
(A. 315, 246).
Dialuric acid crystallizes in needles or prisms, shows a very acid reaction,
and forms salts with i and 2 equivalents of the metals (A. 344, i). It becomes
red in colour in the air, absorbs oxygen and passes into alloxantin :
2C4H4N,04+0=C,H4N40,+2HaO.
Acetyl Dialuric Acid, CH,COOCH(CONH),CO (?), m.p. 211°, is prepared
from dialuric acid and acetic anhydride. It combines with alloxan to form
acetyl-alloxantin.
Tartronyl Dimethyl Urea, HOCH[CON(CH8)]aCO, m.p. 170° with decom-
position (B. 27, 3082).
Nitromalonyl Urea, Nitrobarbituric Acid, Dilituric Acid :
CO<NHCO>CHNO" or CO<NH:CO>C:NOOH (c' lSg7> IL 266)'
is obtained by the action of fuming nitric acid on barbituric acid and by the
oxidation of violuric acid (B. 16, 1135). It crystallizes with three molecules
of vrater and can exchange three hydrogen atoms for metals. Nitromahnyl
Dimethyl Urea, m.p. 148° (B. 28, R. 311).
VOL. I. 2 P
578 ORGANIC CHEMISTRY
Amiiioraalonyl Urea, Aminobarbituric Acid, Uramil, Dialuramide, Murexan,
CO<S5£0>CHNH2, is obtained in the reduction of nitro- and isonitroso-
barbituric acid, and also alloxan phenylhydrazone with hydriodic acid ; by
boiling thionuric acid with water, and by boiling alloxantin with an ammonium
chloride solution. Alloxan remains in solution, whilst uramil crystallizes out.
Uramil, together with alloxan, is formed in the decomposition of murexide and
purpuric acid; also, when ammonium dialurate is heated (A. 333, 71). It is
only slightly soluble in hot water, and crystallizes in colourless, shining needles,
which redden on exposure.
Uramil dissolves in alkalis, forming salts, but prolonged action of alkalis
causes decomposition into urea and aminomalonic acid, and other bodies (A.
333, 77). When a solution of uramil is boiled with ammonia, murexide (p. 580)
is formed. Nitric acid converts uramil into alloxan. Oxidation with perman-
ganate (A. 333, 91). Acetyl Uramil, CH,CO.NHCH(CONH)2CO, is obtained
from uramil and acetic anhydride ; its metallic salts form well-defined crystals.
Thionuric Acid, Sulphaminobarbituric Acid, HO,S.NH.CH(CONH)aCO,
and alkyl thionuric acids are obtained as ammonium salts from alloxan or violuric
acid (below) ; or from alkylated alloxans and ammonium sulphite ; or methyl
ammonium sulphite. They are decomposed by acids into sulphuric acid and
uramil or alkyl uramil. Dimethyl ammonium sulphite and alloxan yield a true
bisulphite compound (see p. 579), which is decomposed into its components
by acids (A. 333, 93).
Alkyl Uramils.
In order to define the position of the alkyl groups the carbon and nitrogen
atoms of uramil aje numbered from i to 7, as is the uric acid (or purine) ring
(P- 8°3) : , 6
^Methyl Uramil, CO(NHCO)2CH.NHCH3; ^-Dimethyl t7rami/,CO[N(CH3)-
CQjgCHNH,; 1,^-Trimcthyl Uramil are obtained from the corresponding
thionuric acids (see above) ; the i,^~ Dimethyl Uramil is also produced by methy-
lating uramil. Dibarbituryl Methylamine, CH8N[CH(CONH)2CO]2, decomposes
at 280°, is formed from alloxantin and methylamine hydrochloride (]. pr. Ch.
[2] 73, 473).
5-Methyl Uramil, CO(NHCO)aC(CH,).NH2, m.p. 237°, and $-Ethyl Uramil,
m.p. 216°, are obtained from C-alkyl barbituric acid by bromination and the
action of alcoholic ammonia (A. 335, 359).
Pscudouric Acid, Carbamido-malonyl-urea, CO<^'^Q>CH.NHCONH2, is
produced, as an ammonium salt, from uramil and urea at 180° ; as a potassium
salt from uramil or murexide and potassium cyanate.
j-Monomethyl Pseudouric Acid', it$-Dimcthyl Pscudouric Acid; 1,3,7-
Trimethyl Pseudouric Acid', i,$-Diethyl Pscudouric Acid are prepared from
the corresponding alkyl uramils and potassium cyanate. When heated with
oxalic acid to 150°, or when boiled with hydrochloric acid, they change into the
corresponding uric acids (B. 30, 559, 1823).
Phenyl Pscudouric Acid, (C4H,Oa).NHCONHC,H,, is prepared from uramil
and phenyl cyanate (C. 1900, 1. 806).
N"FT CVSH^
Thlouramil, CO<JJg-£g^>C.NHf, results when a solution of potassium
urate is heated with ammonium sulphide to 155-160° (B. 28, R. 909 ; A. 288,
157). It is a strong acid. Its solution imparts an orange colour to a pine chip.
It gives the murexide test (p. 580). Nitric acid oxidizes it to sulphuric acid
and alloxan. p-Thiopseudouric Acid, CO<^g^^>C.NHCO.NHa, is ob-
tained from thiouramil and potassium cyanate (A. 288, 171).
Alloxan, Mesoxalyl Urea, CO<^'co>co' *s Pr°duced by the
careful oxidation of uric acid, or alloxantin, with nitric acid, chlorine,
ALLOXAN 579
or bromine. Alloxan crystallizes from warm water in long, shining,
rhombic prisms, with 4 molecules of H2O, the crystals having the
formula : CO(NHCO)2C(OH)2+3H2O. When exposed to the air they
effloresce with separation of 3H2O. The last molecule of water is
intimately combined (p. 562), as in mesoxalic acid, and does not escape
until heated to 150°.
Alloxan is easily soluble in water, has a very acid reaction, and possesses a
disagreeable taste. The solution placed on the skin slowly stains it a purple
red. Ferrous salts impart a deep indigo blue colour to the solution. When
hydrocyanic acid and ammonia are added to the aqueous solution, the alloxan
breaks down into COa, dialuric acid, and oxaluramide (p. 575), which separates
as a white precipitate (reaction for detection of alloxan).
Alloxan is the parent substance for the preparation of numerous derivatives
(Baeyer, A. 127, i, 199 ; 130, 129), which have in part already received mention,
and some of which will be discussed after alloxan. These genetic relationships
are expressed in the following diagram :
(10)
/NH.CO
. .
UramU.
OK v\NH.CO/~ '"TZT ^XNH.CO^^ w«i
\NH.CO Violuric Acid. (7)
Parabanic Acid.
(i) Reducing agents, e.g. hydriodic acid, SnCla, HaS, or Zn and hydrochloric
acid, convert alloxan in the cold into alloxantin (p. 580) ; (2) on warming, into
dialuric acid (p. 577). (3) Alloxantin digested with concentrated sulphuric acid
becomes barbituric acid (p. 576) ; (4) fuming nitric acid changes it to dilituric
acid; (5) and with potassium nitrite it yields violuric acid. (6) (7) Uramil
results from the reduction of dilituric acid and violuric acid. (8) Dilituric acid
is formed when violuric acid is oxidized. (9) Hydroxylamine converts alloxan
into its oxime — violuric acid. (10) Boiling dilute nitric acid oxidizes alloxan
to parabanic acid and COa.
The primary alkali sulphites unite with alloxan just as they do with mesoxalic
acid, and crystalline compounds are obtained, e.g. C4HaNaO4.KHSO3-f HaO.
Pure alloxan can be preserved without undergoing decomposition, but in the
presence of even minute quantities of nitric acid it is converted into alloxantin.
Alkalis or calcium or barium hydroxide change it to alloxanic acid, even when
acting in the cold. Its aqueous solution undergoes a gradual decomposition
(more rapid on heating) into alloxantin, parabanic acid, and CO,.
Alloxan Phenylhydrazone, m.p. 284° (B. 24, 4140 ; 31, 1972).
Alloxan Semicarbazide (B. 30, 131). Alloxan unites with aromatic amines
to form dyes of quinonoid character (Vol. II.) (A. 333, 36 ; J. pr. Ch. [2] 73,
XN=C.CO.NH
449). o-Phenylene diamine produces Alloxazine, C,H4< . Sub-
XN=C.NH.CO
stances with an active CHa-group readily react with alloxan (A. 255, 230, etc.).
Methyl Alloxan, CQ<ffffH^~ro>CO, is produced by the oxidation of
methyl uric acid.
Dimethyl Alloxan, CO[N(CH,).CO],CO, is produced when aqueous chlorine
(from hydrochloric acid and KC1OS) acts on theme ; and by the careful oxidation
of tetramethyl alloxantin (B. 27, 3082). When it is boiled with nitric acid,
methyl and dimethyl parabanic acid are formed.
Diethyl Alloxan, B. 30, 1814.
Dibromomalonyl Urea, Dibromobarbituric Acid, BraC(CONH)aCO, results when
mine acts on barbituric acid, nitro-, amido- and isonitroso-barbituric acids.
58o ORGANIC CHEMISTRY
Oxlmldomesoxalyl Urea, Isonitrosobarbituric Acid, VioluricAcid, CO(NHCO)t-
C:NOH, the oxime of alloxan, the first known " ketoxime," is obtained by the
action of potassium nitrite on barbituric acid, and of hydroxylamine on
alloxan. It unites with metals to form blue, violet, or yellow coloured salts
(B. 32, 1723). When heated with the alkalis, it breaks down into urea and
isonitrosomalonic acid (p. 563). Oximidomesoxalyl Dimethyl Urea, m.p. 141*
(B. 28, 3142 ; R. 912). Diethyl Violuric Acid (B. 30, 1816).
Alloxanic Acid, NH2.CO.NH.CO.CO.COaH. If barium hydroxide solution
be added to a warm solution of alloxan as long as the precipitate which forms
continues to dissolve, barium alloxanate, C4HaN2O6Ba+4HaO, will separate
out in needles when the solution cools. To obtain the free acid, the barium salt
is decomposed with sulphuric acid and the liquid is evaporated at a temperature
of 30-40°, whereby a mass of crystals is obtained. Water dissolves them easily.
Alloxanic acid is a dibasic acid, inasmuch as both the hydrogen of carboxyl and
of the imide group can be replaced by metals. When the salts are boiled
with water, they decompose into urea and mesoxalates (p. 562).
DinreYdes. — When the ureides, parabanic acid, alloxan and di-
methyl alloxan are reduced, there is probably combination of the
reduced with the still unreduced molecules (see Vol. II., Quinhydrone),
whereby the diureides, oxalantin, alloxantin and amalic acid are
formed (comp. A. 333, 63 ; 344, 17).
Oxalantin, Leucoturic Acid, C8H,N4O6, is obtained by the reduction of
parabanic acid.
Alloxantin, cO(NHCO)aa:C(OH)>O+3HaO (?), is obtained (i) by reducing
alloxan with SnCl?, zinc and hydrochloric acid, or HaS in the cold ; (2) by
mixing solutions of alloxan and dialuric acid ; (3) from uric acid and dilute
nitric acid (A. 147, 367) ; (4) from convicin, a substance occurring in broad
beans, Vicia faba minor, and in vetches, Vicia sativa, when they are
heated with sulphuric or hydrochloric acid (B. 29, 2106). It crystallizes
from hot HaO in small, hard prisms with 3HaO and turns red in an atmo-
sphere containing ammonia. Its solution has an acid reaction ; ferric chloride
and ammonia give it a deep blue colour, and barium hydroxide solution
produces a violet precipitate, which on boiling is converted into a mixture of
barium alloxanate and dialurate. On boiling alloxantin with dilute sulphuric
acid, it changes into the ammonium salt of Hydurilic Acid, C8H8N4Oe+ 2H?O.
It combines with cyanamide, forming IsouricAcid, NC.NHCH(CONH)aCO, which
yields uric acid when boiled with hydrochloric acid, and y-thiopseudouric acid,
HaN.CS.NHCH(CONH)aCO, when heated with ammonium sulphide (B. 33,
2563).
Tetramethyl Alloxantin, Amalic Acid, C8(CH3)4N4O7, is formed by the
action of nitric acid or chlorine water on theme, or, better, by the reduction
of dimethyl alloxan (see above) with hydrogen sulphide (A. 215, 258).
Purpuric Acid, C8H6NeO6, is prepared from murexide (the salt of this
acid) by passing hydrochloric acid gas into its solution in glacial acetic acid.
It is an orange-red powder, which is immediately decomposed into alloxan and
uramil by the action of water (J. pr. Ch. [2] 73, 463).
Murexide, C8H4N,O6(NH4)+HaO (structural formula, see below), is the
ammonium salt of purpuric acid. It is formed (i ) from alloxantin and ammonium
acetate and carbonate when they are heated ; (2) by mixing alloxan and uramil
in ammoniacal solution ; (3) by careful oxidation of uric acid with dilute nitric
acid (see above, Alloxantin) and adding ammonia to the residue on evaporation
(murexide reaction, C. 1898, I. 665 ; A. 333, 28). It forms tables or prisms of
a gold-green colour, which dissolve in water to a purple-red coloured solution.
Sodium Purpurate, C8H4N8O6Na-f-H2O, is formed from murexide and sodium
chloride ; potassium purpurate also from the di-potassium salt of uramil and
iodine.
Hydrochloric acid decomposes murexide partially into uramil and alloxan,
and partly into ammonia and alloxantin. i,3-Dimethyl uramil and alloxan, also
1,3-dimethyl alloxan and uramil, give two different murexides, showing that
URIC ACID 581
the molecule is an unsymmetrical one. 5-Alkyl uramils (p. 578) do not yield a
murexide ; 7-alkyl uramils lose alcohol and form salts of a simple purpuric acid ;
therefore, purpuric acid is considered to be a.ci-barbituryl imidoalloxan, and
murexide, the ammonium salt to have the formula :
/NH.CO.C— N=C(CONH)aCO
\NH C.ONH4
(A. 333, 22 ; C. 1904, II. 316 ; J. pr. Ch. [2] 73, 499).
NH— CO
Uric Acid, c6H4N4O3,CO C— NHX is a white, crystalline,
I II >CO
NH— C— NHX
sandy powder, discovered by Scheele in 1776, in urinary calculi. It
occurs in the fluids of the muscles, in the blood and in the urine,
especially of the carnivorae, whilst that of the herbivorae contains
mostly hippuric acid ; also, in the excrements of birds (guano), reptiles,
and insects. When urine is exposed for a while to the air, uric acid
separates ; this also occurs in the organism (formation of gravel and
joint concretions) in certain abnormal conditions.
History (B. 32, 435). — Liebig and Wohler (1826) showed that numerous deriva-
tives could be obtained from uric acid. Their relationships and constitution
were chiefly explained by Baeyer in 1863 and 1864. In consequence of certain
experiments of A. Strecker, Medicus (1875) proposed the structural formula
given above for the acid. This was conclusively proved by E. Fischer in his
investigation of the methylated uric acids.
The results derived from analysis were confirmed by the synthesis
made in 1888 by R. Behrend and 0. Roosen, who proceeded from
acetoacetic ester and urea (p. 585). Horbaczewski (1882-1887) had
previously made syntheses of uric acid at elevated temperatures, but
obtained poor yields. They consisted in melting together glycocoll,
trichlorolactamide, etc., with urea. No clue as to the constitution of
the acid could be deduced from these. In 1895 E. Fischer and Lorenz
Ach showed how pseudouric acid (p. 578), previously synthesized
by A. Baeyer, could, by fusion with oxalic acid, be converted into
uric acid.
Preparation. — Uric acid is best prepared from guano or the
excrements of reptiles.
Properties. — Uric acid is a shining, white powder. It is odourless
and tasteless, insoluble in alcohol and ether, and dissolves with
difficulty in water ; i part requires 88,000 parts of water at 18° (C.
1900, II. 42) for its solution, and 1800 parts at 100°. Its solution
remains long supersaturated. Its solubility is increased by the
presence of salts like sodium phosphate and borate. Water precipi-
tates it from its solution in concentrated sulphuric acid (B. 34, 263).
On evaporating uric acid to dryness with nitric acid, a yellow residue is
obtained, which assumes a purple-red colour if moistened with ammonia,
or violet with potassium or sodium hydroxides (murexide reaction
p. 580). When heated, uric acid decomposes into NH3, CO2, urea and
cyanuric acid. The action of chloride and oxychloride of phosphorus
582 ORGANIC CHEMISTRY
on uric acid and alkyl uric acids is of special importance in the chemistry
of the uric acid group. The reaction is comparable to the conversion
of acid amides into imidochlorides. The resulting compounds are
highly reactive, whereby the chlorine can be exchanged for alkoxyl,
hydroxyl, hydrosulphyl, the amino-group, iodine, and sometimes also
hydrogen. The inter-connection between the members of the uric
acid group can be elucidated by these chemical changes (B.
32, 445).
Carbon disulphide, when heated under pressure with uric acid,
NH.CO.CNHv
forms with it Thioxanthine \ ij ^CSH, which also results when
CO.NHC— 1ST
y-thiopseudouric acid (p. 580) is boiled with mineral acids (C.
1902, I. 548 ; B. 34, 2563). When heated with ammonium sulphide
urea is converted into thiouramil (p. 578). Electrolytic reduction in
/NH.CH2.CH.NHV
sulphuric acid solution produces Purone CCX /CO (?)
\NH CH.NH/
a neutral body, together with the isomeric isopurone, soluble in alkalis
and acids, which can also be produced by the transformation of purone,
and also tetrahydrouric acid, C5H8N4O3. Similar products are also
obtained from the methylated uric acids (below) (B. 34, 258). Form-
aldehyde unites with uric acid to form mono- and di-formaldehyde uric
acid (A. 299, 340).
Salts. — Uric acid is a weak dibasic acid. It forms hydrogen salts
with the alkali carbonates. The normal alkali salts are obtained
by dissolving the acid in potassium or sodium hydroxide. When
C02 is conducted through the alkaline solution, the primary salts
are precipitated.
The potassium salt, C,H,N4O8K, dissolves in 800 parts of water at 20°; the
sodium and ammonium salts are more insoluble ; lithium salt (Lipowite)
is much more soluble (in 368 parts of water at 19°) (A. 122, 241), hence
lithium mineral waters are used in such diseases where there is an excessive
secretion of uric acid. This salt is, however, greatly surpassed by the piper azine
salt, C,H4N4Ot.NH<^«-™»\NH (Finzelberg), which dissolves in 50 parts
of water at 17° (B. 23, 3718). The lysidint or the methyl glyoxalidine salt (Laden-
burg) is even more soluble (one part in 6 parts of water ; B. 27, 2952).
Methyl Uric Acids (B. 32, 2721 ; A. 309, 260). — The four hydrogen atoms
in uric acid can be replaced by methyl. In all methyl uric acids, including
tetramethyl uric acid, the methyl groups are linked to nitrogen ; this, in con-
junction with the decompositions and synthesis of uric acid, argues for formula I.,
without, however, in the light of our present representations, excluding formulae
such as II. (comp. below, the isomeric 3 -methyl uric acids) :
NH— CO N=C.OH
I. CO C— NHV II. HO.C C-NH,
II >CO || || >C.OH.
NH— C-NH/ N-C N^
To indicate the position of the methyl groups in the methyl uric acids and
the constitution of other bodies containing the same hetero-twin ring, E. Fischer
suggested that the carbon and nitrogen atoms of the nucleus contained in uric
acid and bodies related to it be numbered, and that the hydrogen compound
of the nucleus, C6N4, which could have two formulae, should be called " purine "
(from purum and uricum) :
URIC ACID 583
N=CH N=CH
II II
— ^ 8 HC C— NHV HC C Nx
I >c || || >CH || || VH.
N C-N N-C N^ N-C-NH/
Purine (B. 32, 449).
The methyl uric acids are obtained (i ) by treatment of lead and potassium
urates and methyl urates with iodomethane ; (2) from the formaldehyde uric
acid compound (p. 582) by reduction (C. 1900, II. 459) ; (3) from the corresponding
pseudouric acid (p. 578) through loss of water. Whilst formula I. for uric acid
indicates the possibility of only four isomeric monomethyl uric acids, actually
six are known, as well as six dimethyl uric acids, four trimethyl uric acids and
one tetramethyl uric acid.
g-Methyl Uric Acid (ft) and ^-Methyl Uric Acid (a) are 'formed from uric acid.
The former yields alloxan, the latter methyl alloxan, when treated with nitric
acid ; both are converted into glycocoll when heated with hydrochloric acid.
j-Methyl Uric Acid (y) is formed from 7-methyl pseudouric acid (p. 578). §-M ethyl
Uric Acid, prepared from i,4-dimethyl uracil (A. 309, 260) and ^-methyl uric
acid, prepared by methylating uric acid in a weak acetic acid solution are both
different from a-methyl uric acid, although they contain the methyl group in the
3-position. i-Methyl Uric Acid («-) is also formed from monomethyl alloxan
(B. 32, 2721). The 3-methyl uric amides (a, 8, and £) when oxidized with per-
manganate, give rise to the same a-methyl allantoin as it obtained from g-methyl
uric acid. Similarly, i- and 7-methyl uric acid yield the same j8-methyl allantoin,
which can be explained by the assumption of the existence of a common! sym-
metrical intermediate compound (A. 333, 145) :
COOH
/NH C.CO.NH ,NH C NHX /NH.C.CO NH
ccxr ii i °co< i ;>cooco< H i
N(CH3).C.NH.CO-> XN(CH8).C(OH).NH/ XNH.C.N(CH,).CO
C0
NH - CH-NH, /N(CH8).CH —
, /8. — V
>CO C0< | >CO
/ X - /
XN(CH3).CO H2N NH - CO
a-Methyl Allantoin. -^ 0-Methyl Allantoin.
COOH
N(CH3)C.CO.NH , N(CH,)-C - NHV /NH.C.CO.N.CH,
|| | OCO< | NCOOCO/ [| ]
NH — C.NH.CO^ XNH - C(OH).NH/ NNH.C.NHCO
3,9-Dimethyl Uric Acid (a) is obtained from basic lead urate and iodomethane.
j,g-Dimethyl Uric Acid (ft) (B. 17, 1780). i,^-Dimethyl Uric Acid (y), is prepared
from i,3-dimethyl pseudouric acid (p. 578) ; and from i,3-dimethyl 4,5-diamino-
uracil (see also Theophyllin, p. 590). ^^-Dimethyl Uric Acid (8) is formed from
7-methyl uric acid (see also Theobromine, p. 589). i.'j-Dimethyl Uric Acid is
produced from i,7-Dimethyl Uric Acid, i ,g-Dimethyl Uric Acid (B. 32, 464).
1,3,7-Trimethyl Uric Acidt prepared from 1,3, 7- trimethyl pseudouric acid (a),
is identical with hydroxycaffeine (B. 30, 567). s.'j.g-Trimethyl Uric Acid (a) is
formed from 7,9-dimethyl uric acid. i,3,g-Trimethyl Uric Acid is produced from
i,3-dimethyl uric acid. i.j.g-Trimethyl Uric Acid (B. 32, 466).
Tetramethyl Uric Acid is prepared from potassium trimethyl urate and iodo-
methane. Isomeric with it is methoxy caffeine, i ,3, 7 -trimethyl 2,6-dioxy-S-methoxy-
5*4
ORGANIC CHEMISTRY
purine, which is prepared from bromo- or chloro-caffeme by the action ot sodium
hydroxide in methyl alcohol (B. 32, 467).
Phenyl Uric Acid is prepared from phenyl pseudouric acid (p. 578) (C. 1900,
Purine C8N4H4, m.p. 216°, is the fundamental compound of the uric acid
group (p 583) It cannot be obtained directly from uric acid, but is prepared by
converting uric acid by POC1, (p. 581) into trichloropurine, which, with hydriodic
acid at o°, gives 2,6-diodopurine ; this, on reduction with zinc dust and water
results in purine.
Purine, like uric acid, can also be synthesized as follows :— synthetic
methyl uracil is converted into 5-nitrouracil (p. 585) ; this, with POC1,, yields
2,4-dichloro-5-nitropyrimidine (i ), which with ammonia gives 2 chloro-4-ammo-5-
nitropyrimidine (2); reduction with hydriodic acid gives 4,5-diaminopyrimi-
dine (3), of which the formyl-derivative (4), obtained by the action of formic
acid, is decomposed when heated with water, when purine is formed :
NH— CO
do '
N=C.C1
C— NHV — >CC1 C— NHV
I II >CO H || )CC1
NH^-C.NH / N— C N^
Uric Acid. Trichloropurinc.
N— CI
-CI-C-NEL
II II >CH
N_C — N^
Diiodopurine.
N=CH
-CH C— NHX
II II CH
N— C
Purine.
N=CH
(i) 1 1
C1C C.NO8—
Uc,
N=CH
(2) I |
> C1C CNO, — •
II II
N— C.NH,
N=CH
(3) 1 1
> HC CNH2
II II
N=GH
(4) I !
HC CNH.CHO
II II
N— CNH,
Purine reacts simultaneously as an acid and as a strong base. It is easily soluble
in water, and is stable towards oxidizing agents.
Methyl Purines and other simple purine derivatives are obtained similarly
(B. 31, 2550 ; 39, 250).
OXIDATION OF URIC ACID
Mesoxalyl urea or alloxan and oxalyl urea or parabanic acid
are produced when uric acid is oxidized with nitric acid. When
the acid is carefully oxidized either with cold nitric acid or with
potassium chlorate and hydrochloric acid, it yields mesoxalyl urea
and urea. Allantoin is produced when potassium permanganate, or
iodine in potassium hydroxide, acts on the acid (B. 27, R. 902).
Hydrogen peroxide converts sodium urate into tetracarbonimide,
C4H4N4O4, a weak tetrabasic acid (B. 34, 4130). When air or potas-
sium permanganate acts on the alkaline solution of uric acid (B. 27,
R. 887 ; 28, R. 474), allantoin is formed together with uroxanic acid,
diureidomalonic acid, C5H8N4O8=(NH2CONH)2C(COOH)2 (?) (comp.
A. 333, 151). From this alkali produces oxonic acid, aminohydan-
CO.NH.C[NH8]COOH
idin carboxylic acid, C4H8N,O4=*| | (?). For the
course of these oxidation reactions compare the scheme of oxida-
tion of the methyl uric and to the methyl allantoins (p. 583), and of
methyl uracil (p. 574). These reactions suggest the following diagram,
SYNTHESIS OF URIC ACID
585
in which the breaking-down of alloxan and parabanic acid is con-
sidered :
NH— CO
I
CO C— NH
H— C— NH/
Uric Acid.
C.H.N.O.
Urozanic Acid.
C4H,N304
Oxonic Acid.
NH.CH.NHv
I I >CO
CO CO.NIi/
NH,
AllantolB.
Nil— CO
NH, CO,H
co co
NH— CO
NH, COtH
Mesoxalio
Acid.
Parabanic Acid.
NH, CO,H
CO
I I
NH, COSH
Oxalic
Acid.
NH— CO— NH
C0(?)
NH— CO— NH
Tetracarbooimide.
Uric acid is the diureide of the hypothetical body, CO=C(OH).-
CO2H, or C(OH)2=C(OH)-CO2H, the pseudo-form of the half-
aldehyde of mesoxalic acid, CHO.CO.CO2H, (p. 545).
SYNTHESIS OF URIC ACID ! (l) FROM ACETOACETIC ESTER : (2) FROM
MALONIC ACID I (3) CYANACETYL UREA
(i ) From Acetoacetic Ester : (i ) Acetoacetic ester and urea unite to fi-uramido-
crotonic ester. When this is hydrolyzed with alkali it yields an acid which, in a
free state, splits off water and becomes a cyclic ureide — methyl uracyl. (2) Nitric
acid converts the latter into nitrouracyl carboxylic acid, (3) whose potassium salt
when boiled with water loses a molecule of carbon dioxide, and becomes converted
into the potassium salt of nitrouracyl. (4) The reduction of the latter with tin
and hydrochloric acid gives in part antinouracyl (A. 309, 256) and in part hydroxy-
uracyl or isobarbituric acid. (5) Bromine water oxidizes the latter to isodialuric
acid, which when heated (6) with urea and sulphuric acid yields uric acid (A. 251,
235).
CH,
CO.CH,
Accloacetic
Ester.
NH— CH
Aminouracyl.
NH.CO
I I
CO CH
I [I
NH.C.CH3
Methyl Uracyl.
C— N02
NH,-C— CO2H
Nitrouracylic Acid.
(3)
NH— CO
CO C— NOt
I II
NH— CH
Nitrouracyl.
H
NH— CH
Hydroxyuracyl
(Isobarbituric
Acid).
Isodialuric Acid.
NH.C-NH
Uric Acid.
586
ORGANIC CHEMISTRY
from pseudouric acid by means of molten oxalic acid or boiling hydrochloric acid,
uric acid results (B. 30, 559) :
CO,H
NH.CO
NH.CO
i
1 _ C>
1 1 <2)
>- co C-N OH
CH,
• U<J i-xl.
i i
CO,H
Malonic Add.
NH.CO
Malonyl Urea.
t~\
NH.CO
Oximidomesoxalvl
Urea.
-<-
NH.CO
\jt —
NH.CO
NH.CO
I 1 (4)
v rn PTTTSITT rn"WTT
(5) NCOCNH '
CO CHNH a
NH.CO
— ^ L/w L-rlINrl.LxWiN Ii2
NH.CO
1 1 >co.
NH.C.NHX
Uramil.
Pseudouric Acid.
Uric Acid.
Since alloxan and dimethyl alloxan yield methylated pseudouric acids, methy-
lated uric acids can also be synthesized in this way.
(3) From Cyanacetyl Urea: Urea and cyanacetic acid are condensed to (i)
cyanacetyl urea, and this to (2) 4-aminouracil or 4-ammo-2,6-dioxypyrimidine
(C. 1906, II. 1590 ; B. 41, 532). This, with nitrous acid, gives (3) a nitroso-com-
pound which, with ammonium sulphide, is reduced to (4) 4,5-diaminouracil.
The diamine reacts with chlorocarbonic ester and aqueous sodium hydroxide^to
form (5) a urethane, the sodium compound of which when heated to 180-190° is
converted into (6) sodium urate (W. Traube, B. 33, 3035 ; A. 331, 64) :
NH— CO
CO CH. -
NH, CN
Cyanacetyl Urea.
NH— CO
CO CNH\ -<r5— CO C.NHCO,R
NH— CO
CO CH
I R
NH— C.NH,
4-Aminouracil.
NH— CO
NH— CNH
Uric Acid.
\
>0
(2)
(4)
NH— C.NH,
NH— CO
CO C.NO
I II
NH— C.NH ,
NH— CO
I II
CO C.NH,
I II
NH— C.NH,
4,5-Diaminouracil.
(3)
This synthesis can be generally employed, with the following modifications : —
(1) Replacement of the urea by methylated ureas in the condensation with
cyanacetic acid to obtain methylated uric acids.
(2) Replacement of the chlorocarbonic ester by formic acid ; formyl diamino-
uracil is formed, the sodium compound of which, on being heated, yield xanthine
or methylated xanthines (p. 587).
(3) Condensation of guanidine, instead of urea, with cyanacetic acid to form
2,4,6-diamino-oxypyrimidine ; this is ultimately transformed into guanine (p. 587).
(4) Condensation of cyanacetic acid with thiourea to form 2-thio-4-amino-
6-oxypyrimidine. This is converted into thio-oxypurine which, when oxidized by
nitric acid, yields sulphuric acid and hypoxanthine (p. 588).
(5) Condensation of malonic nitrile with thiourea to form 2-thio-4,6-diamino-
pyrimidine (below), which, analogously to the above, is converted through its
nitrous compound into 2-thib-4,5,6-triammopyrimidine (2), of which the potassium
salt of the formyl-compound, when heated yields 2-thio-6-aminopurine (3) ; oxida-
tion with H2O2 produces sulphuric acid and adenine (4):
N=CNHt
N— CNH,
N=CNH,
(i)HSC CH->(2)HSC CNH,->(3)HSC CNH
II II II II II II
N— C.NH, N— CNH, N— C— N
Thioaminopurine.
N=C.NH,
C
H
->(4)HC CNH
N-C—
Adenine.
CONVERSION OF URIC ACID INTO XANTHINE 587
Xanthins Group. — Guanine, xanthine, hypoxanthine, and adenine stand in
close relation to uric acid. Like it, they occur as products of the metabolism of the
animal organism, and are most easily produced from nucle'inic acids (p. 573) by
boiling them with water (comp. B. 37, 708). Xanthine and hypoxanthine occur
in the extract of tea. Bodies of the xanthine group are found in the juice of the
sugar beet (B. 29, 2645).
HN— CO
CO C— NHv -<-
1 H >CH
HN— C W
Xanthine.
HN— CO
HN:C C— NHV
1 II >CH
HN— C W
Guanine.
HN— CO
CH C— NH\ •<-
II II >CH
N— C N^
Hypoxanthine.
HN— C:NH
1 1
— - CHC— NHv
II II >CH
N— C N^
Adenine.
Guanine is
inidine on <
changed into xanthine
decomposition (p. 455).
by the action of nitrous acid and yields
It is, therefore, to be regarded as being
xanthine in which a guanidine residue takes the place of a urea residue, i.e. the
oxygen of a CO-group is replaced by NH. Adenine stands in similar relation to
hypoxanthine as guanine to xanthine, in that its conversion into hypoxanthine
is brought about by nitrous acid.
CONVERSION OF URIC ACID INTO XANTHINE, GUANINE,
HYPOXANTHINE AND ADENINE
Potassium urate and phosphorus oxychloride produce 8-oxy-2, 6-dichloropurine,
which on further treatment with phosphorus oxychloride yields 2, 6, 8-trichloro-
purine, m.p. 188°. The latter is a weak acid, and gives, on methylation, a
mixture of the two isomeric forms of methyl trichloropurine.
H— CO N=C.C1
I (i) I I
3 C— NHV ^C.Cl Cr-^n^
II >CO || || >CO
H— C— NHX N C— NHX
UricAoid. 8-Oxy-2, 6-dichloropurine. Trichloropurine.
(3) Ml (9)
=CNH
I
(5)
y
NH— CO
I I
CC1 C-NH
Dichloroadenine.
=CN]
I C— NHs
7) NH— CO
-> I I
x H2NC C— NHs
II >cci ||
N C N^ N <
Dichlorohypoxanthin*.
4
NH— CO
C— NHv
II >CH
CH
N C N
HrpozanUiina.
N=COC2H6
I I
CaH5OC C— NHx
3,6-Diethoxy- 8-chloro-
purine( m.p. 209°).
NH— CO
CO C— NHV
I II >CH
NH— C N^
Xanthine.
The chlorine atoms 2 and 6 are easily substituted in the presence of alkalis "by
OH, C2H6O, and NH2 ; but in the 8-position the chlorine atom can be replaced by
fuming hydrochloric acid, but not by alkalis. On this behaviour is based the
synthesis of xanthine, guanine, hypoxanthine and adenine (B. 30, 2220, 2226).
588 ORGANIC CHEMISTRY
Uric acid is (i) acted on by POC18 to form 8-o*y-2,6-dichloropurine, and is
similarly (2) converted into trichloropurine. The latter, with aqueous ammonia
at 100° gives (3) dichlor adenine, with aqueous KOH at 100° (5) dichlorohypo-
xanthine, and with sodium ethoxide (9), 2,6-dimethoxy-8-chIoropurine. These
three substances, when reduced with hydriodic acid yield (4) adenine, (6) hypo-
xanthine, and (10) xanthine. Further, dichlorohypoxanthine and alcoholic
ammonia (7) yield chloroguanine, and this, with hydriodic acid, (8) guanine.
For the synthetic preparation of these four substances see p. 586, scheme 3,
for the synthesis of uric acid.
Xanthine and the methylated xanthines (p. 589) are reduced electrolytically
in sulphuric acid solution, whereby the oxygen atom in position 6 is replaced by
two hydrogen atoms to form the desoxy-compound, which easily loses two hydrogen
atoms by oxidation to form oxypurine. Similarly, guanine yields desoxy guanine
and this 2-atninopurine, similarly with adenine (Tafel, B. 33, 3369 ; 84, 1165) :
NH.CO.C.NH, 4H NH.CHa.C.NHv o N:CH— C.NH
I II >CH - > | || >CH - > | ||
CO.NH.C— N^ CO.NH.C— N^ CO.NH.C—
Xanthine. Desoxyxanthine. 2-Oxypurine (isomeric with
Hypoxanthine).
Desoxy xanthine, desoxyheteroxanthine, and desoxy paraxanthine are decomposed
by acids into CO2, NH, and amino-methyl-imidazolone :
NR.CO.C.NR. 2HaO NHR.CO.CH.NR
II >CH - > |
.NH.C— N^ CO— N
.
I
CO.
whilst desoxytheophylline and desoxy caffeine, xanthines, in which the methyl
group occupies the 3-position, are far more stable (B. 41, 2546).
Xanthine, 2,6-Dioxypurine, C,N4H4Oa (constitutional formula, above), occurs
in small quantities in animal secretions, such as urine, blood, the liver, and some-
times in urinary calculi ; it is found, also, in extract of tea. It is prepared by
the action of nitrous acid on guanine in sulphuric acid solution (B. 32, 468) ; also,
by heating the sodium salt of formyl-4,5-diaminouracil (p. 586) to 220°. It
forms a white amorphous mass, which is somewhat soluble in boiling water, and
combines with both acids and alkalis. It dissolves easily in boiling ammonia, from
a solution in which silver nitrate precipitates a compound, C,HaAgaN4Oa+H2O.
The corresponding lead compound is converted into theobromine (dimethyl
xanthine) when heated with iodomethane at 100°. Methylation in alkaline
aqueous solutions produces caffeine. When heated with potassium chlorate and
hydrochloric acid, xanthine (analogously to caffeine, p. 590) is broken down into
alloxan and urea.
CO.NH.C.NH,
S-Thioxanthine, \ \\ >SC, is formed when y-thiopseudouric acid
NH.CO.C.NH/
(P- 579) is heated ; and from 4,5-diaminouracil (p. 586), and carbon disulphide
(C. 1903, II. 80).
Guanine, 2~Amino-6-oxypurine, CjNjHjO (constitutional formula, p. 587),
occurs in the pancreas of some animals, and particularly in guano ; also in the
silvery matter of the scales of bleak (connected with the dace), Alburnus lucidus
(C. 1898, I. 1132). It is readily synthesized by converting cyanacetyl guanidine
XNH.CO.C.NH2
(p. 586) into triamino-oxypyrimidine, H^.C^ || , and heating this
\N - CNH,
with formic acid (B. 33, 1371).
Guanine forms an amorphous powder, insoluble in water, alcohol and ether.
It combines with one and two equivalents of acids forming crystalline salts, such
as C6H,N6O.2HC1 ; and also with alkalis to form crystalline compounds. Silver
nitrate precipitates a crystalline compound, C6H6N6O.AgNO3, from a nitric acid
solution of the substance. Nitrous acid converts guanine into xanthine. Potas-
sium chloride and hydrochloric acid decompose it into parabanic acid, guanidine
and carbon dioxide (p. 455).
Bromoguanine is formed from guanine and bromine. Fuming hydrochloric
CONVERSION OF URIC ACID INTO ADENINE 589
acid converts it into 2-Amino-6,8-dioxypurine. Chloroguanine is prepared from
dichlorohypoxanthine and alcoholic ammonia. With hydriodic acid it yields
guanine.
Hypoxanthine, 6-Oxypurine, C6N4H4O (constitutional formula p. 587) almost
invariably accompanies xanthine in the animal organism, and can be differentiated
from it particularly by the slight solubi lity of its hydrochloride. It forms needles,
soluble with difficulty in water, but soluble in acids and alkalis, and in ammoniacal
solution is precipitated by silver nitrate which forms C6H2Ag2N4O+H2O. Di-
f methyl Hypoxanthine is decomposed when heated with hydrochloric acid into
* methylamine and sarcosine (p. 387) (B. 26, 1914). The position of the oxygen
atom is determined by the transformation of adenine into hypoxanthine by
nitrous acid ; also by its formation from the decomposition of the synthetic
/NH.CO.C.NH,
2-thio-6-oxypurine HSC1 ^CH.
^N C— N^
Adenine, 6-Aminopurine, C6N6H6 (constitutional formula, p. 587). m.p. 360-
368° with decomposition (B. 30, 2242), is a polymer of hydrocyanic acid.
It is obtained from the pancreas of cattle, and occurs in extract of tea. It
crystallizes with 3 molecules of water in mother-of-pearl crystals, which lose water
at 54° and turn white. Nitrous acid converts it into hypoxanthine ; hydrochloric
acid at 180-220° into glycocoll, ammonia, formic acid and carbon dioxide
(Kossel, B. 23, 225 ; 26, 1914). The position of the amino-group is fixed by
the connection of adenine with 6-amino-2,8-dioxypurine through dichloradenine ;
fuming hydrochloric acid converts dichloradenine into 6-amino-2,8-dioxypurine,
which on decomposition does not yield guanidine, showing that the amino-
group must be in the 6-position and not in the 2 or 8.
Synthesis of adenine from 2-thip-4,5,6-triaminopyrimidine (p. 587). The
analogous formation of purine derivatives still richer in nitrogen, such as 2-amino-
adenine, C6N4H2(NH2),, from malonic nitrile, guanidine, etc., see B. 37, 4544.
Heteroxanthine,Theobromine, Paraxanthine,Theophylline, Theine (or Caffeine),
are all methyl derivatives of xanthine.
in urine, and is formed from theobromine by the loss of methyl. By raethylation
it is converted into caffeine ; hydrochloric acid decompose it into sarcosine
(B. 32, 469). Electrolytic reduction produces desoxyheteroxanthine, which on
oxidation forms 7 -methyl-2-oxy purine (comp. p. 588). The isomeric ^-methyl
xanthine is prepared from 3-methyl uric acid (p. 583), and also from cyanacetyl
methyl urea, CN.CHaCO.NHCONH.CH8, as shown in diagram 3 of the uric acid
synthesis (p. 586).
Theobromine, 3,7-Dimethyl Xanthine, C6H2N4O2[3,7](CH8), occurs in the cocoa
beans of Theobroma cacao ; it is artificially prepared by methylating xanthine
(p. 588) or 3-methyl xanthine (B. 33, 3050).
Theobromine forms a bitter-tasting crystalline powder, slightly soluble in hot
water and alcohol, but is fairly easily soluble in ammonia. It sublimes unchanged
when carefully heated at 290°. Its reaction is neutral, but it forms crystalline
salts with acids, which are decomposed by excess of water. Its silver salt,
C7H7AgN4Oj, and iodomethane produces caffeine. Electrolytic reduction pro-
duces desoxy theobromine, which on oxidation yields 3,7-dimethyl-2-oxypurine
(comp. p. 588). Theobromine on oxidation is converted into oxy-3,7-dimethyl
uric acid (B. 31, 1450) ; potassium chlorate and hydrochloric acid decompose it
into monoethyl alloxan and monomethyl urea. The action of dry chlorine on
theobromine (B. 30, 2604).
Theobromic Acid, C7H8N4Of.
Pseudotheobromine is formed from the silver xanthine compound and iodo-
methane (C. 1898, 1. 1132).
Paraxanthine, 1,7 '-Dimethyl Xanthine, C6H2N4O2ri,7](CH8)2, m.p. 289°, occurs
in urine (B. 18, 3406). It is prepared from theobromine by the removal of
methyl and its replacement in another position (see below for synthesis). It is
obtained from i,7-dimethyl uric acid, as theobromine is from the 3,7-compound
(B. 82, 471). Methylation produces caffeine (B. 30, 554)-
590 ORGANIC CHEMISTRY
SYNTHESIS OF HETEROXANTHINE, THEOBROMINE, AND PARAXANTHINE
7-Methyl pseudouric acid yields y-methyl uric acid, which by methylation
gives 3 7 -dimethyl uric acid. POC18 converts (i) s.y-dimethyl uric acid into
chlorotheobromine, which is reduced (2) by hydriodic acid to theobromine,
and which is formed from theobromine (3) by iodine chloride.
When theobromine is heated with POC1, and PC15 (4) it loses a methyl group
and forms y-methyl 2,6-dichloropurine which with hot fuming hydrochloric acid
2-chloropurine from which hot fuming hydrochloric acid produces (8) paraxanthine
(B. 32, 469).
NH— CO NH— CO /,N NH— CO N=CC1
I CH, (i) CH3 J3) I I CH, (4) I I CH,
CO C-N^ '— > CO C-N< 8±T CO C-N< *—>- CC1 C-N<
I | Sco I y >cci -r> i H >CH H || >CH
CHsN C-Nlf CH,N C-N ™ CH,N— C-N — C-N
3-7-Dimethyl Uric Acid. Chlorotheobromine. Theobromine. 7-Methyl- a,6-di-
chloropurine (m.p. 200).
(6)
Y
Y (5)
NH— CO
CH3N CO CH,N—
-CO
NH— CO
1 1 CH3 (7)
CCI C— N< — $
N C— N*^
1 1 CH3 (8)
CCI C— N< — >•
JUU^11
b
NH-
1 CH3
C— N< 3
CH3
CO C— N<
1 II >CH
NH— C— N
7-Methyl-6-oxy-
2-chloropurine.
i,7-Dimethyl-6-
oxy-2-chloropurine.
Par«
knthine.
Heterozanthlna
(m.p. 380').
The constitution of 7-methyl-6-oxy-2-chloropurine is so assigned, because its
reaction product with ammonia gives guanidine when oxidized with chlorine, so
that it must be 7-methyl-6-oxy-2-aminopurine. This establishes the constitution
of heteroxanthine.
The product of methylating 7-methyl-6-oxy-2-chloropurine can only have
the second methyl group in the i -position, whereby the i.y-position of the methyl
group in paraxanthine is determined.
Theophylline, 1,%-Dimethyl Xantkine, m.p. 264°, was discovered in 1888 by
Kossel in tea extract. By the action of methyl iodide on silver theophylline he
obtained caffeine (B. 21, 2164). Theophylline has been synthetically prepared
from 1,3- or y-dimethyl uric acid by its conversion with PC15 into chlorotheo-
phylline, m.p. 300° with decomposition ; hydriodic acid reduces it to theophylline
(E. Fischer, B. 30, 553). A shorter synthesis is from cyanacetyl dimethyl urea,
CN.CHa.CON(CH3)CONH.CH3, in which, following diagram 3 of the uric acid
synthesis (p. 586), this body is converted into: i,3-dimethyl 4,5-diaminouracil,
of which the formyl-compound (2) is converted into theophylline when warmed
with alkalis (B. 33, 3052 ; C. 1903, I. 370).
CH8N— CO CH3N— CO CH8N— CO
OC C— NH W. OC C— NH^CH <*>> OC CNH.CHO
CH8N— C N^ CHSN— C *T " CH3N— C.NHa
Caffeine, Coffeine, Theine, i.^.j-Trimethyl Xanthine, C8H10N4O,, m.p. 239°,
occurs in the leaves and beans of the coffee tree (0-5 per cent.), in tea (2-4 per cent.),
in Paraguay tea (from Ilex Paraguay ensis), in guarana (about 5 per cent.), the
roasted pulp of the fruit of Paullinia sorbilis, and in the kola nuts (3 percent.).
It is also found in minute quantities in cocoa. It is used in medicine as a nerve
stimulant.
Caffeine crystallizes with one molecule of water. It has a feeble bitter taste,
and forms salts with the strong mineral acids, which are readily decomposed by
water. On evaporating a solution of chlorine water containing traces of caffeine
there remains a reddish-brown spot, which acquires a beautiful violet-red colour
CAFFEINE, COFFEINE, THEINE 591
when dissolved in aqueous ammonia. See also sarcosme (p. 387). Electrolytic
reduction converts caffeine into Desoxycaffeinc (comp. p. 588).
Sodium hydroxide converts theme into caffeidine carboxylic acid, C7HUN4O.-
CO2H, which readily decomposes into COa and caffeidine, C7H,2N4O (B. 16, 2309).
For other caffeine derivatives (apocaffelne, caff uric acid, caffolin) see A. 215, 261,
and 228, 141.
Chlorine water breaks caffeine up into dimethyl alloxan and methyl urea
(p- 579)- Chlorine and bromine convert caffeine into Chlorocaffeine, m.p. 180°,
and Bromocaffeine, m.p. 206°. Zinc dust reduces both of them to caffeine ;
ammonia and bromocaffeine produce aminocaffeine, which behaves like an aromatic
amine (Vol. II.) in so far that it yields diazocaffeine with nitrous acid, which can
be coupied to form caffeine diazo- bodies (C. 1900, I. 407). Sodium methoxide
converts chlorocaffeme into methoxy caffeine, m.p. 174°, which when heated to
200° is converted into tetramethyl uric acid (B. 35, 1991). The latter is decom-
posed by hydrochloric acid into chloromethane and hydroxy caffeine, m.p. 345°.
This is identical with I ,$,7-trimethyl uric acid. PCI, converts hydroxycaffeine
into chlorocaffeme. Proceeding from dimethyl alloxan, 1,3,7-trimethyl uric
acid may be synthetically made (p. 586), and from this caffeine through chloro-
caffeine. Furthermore, the lower homologues of caffeine — theobromine and
theophylline — can be synthesized, and by introducing methyl into them caffeine
will result. This, then, is an additional synthesis of caffeine (E. Fischer, B. 30,
549)-
Finally, caffeine can be produced from the already synthesized i,3-dimethyl-
4,5-diaminouracil (see above, theophylline) by preparing the formyl compound,
methylating it (below) and heating the product (B. 33, 3054) :
CH8N— CO CH8N— CO CH3N— C
I II
CH8N— C— N' CH8N— C— N' CH8CN-C-NH2
Chlorocaffeine, from 1,3,7- Caffeine Formyl Methyl 4,5-diamino-
Trimethyl-uric Acid. i,3-dimethyl Uracil.
Just as caffeine can be built up by exhaustive methylation of xanthine and the
lower methyl xanthines, so these bodies are obtained by the breaking down of
caffeine. Chlorocaffeine (see above) treated with chlorine and POC1, at low tem-
peratures gives a product in which the 7-methyl group is chlorinated, whilst at
higher temperatures the 3-methyl group is attacked ; if excess of chlorine be
employed a tetrachlorocaffeine results, in which all three methyl groups are
chlorinated. When boiled with water, these methyl groups are lost in the form of
formaldehyde, and by reduction hydrogen may be exchanged for the chlorine
in the a-position (B. 89, 423) :
CH8N— CO CICHjN— CO
OOC_N<£?»-> ioLN<CH«C1-
I II /^ I II >cci
CH.N— C— N C1CH2N— C— *T
8-ChlorocaffeIne. Tetrachlorocaffeine. 8-Chloroianthine.
8- A Iky I Xanthines are obtained from the corresponding uric acids by heating
them with carboxylic anhydrides (C. 1901, II. 71).
NH . COC.NH, ,rH ro x0 NH.CO.C.NPL
|| \CO (CH'C°a)°> I || >CCH.
CO.NH.C.NH/ ^ CO.NH.C.N/
Uric Acid. 8-Methyl Xanthine.
The methyl group in these substances is easily chlorinated : 8-trichloro-
methyl xanthin* can be converted into xanthine 8-carboxylic acids, as can
^-methyl xanthin* 8-carboxylic acid, CBH,N4O2[3]CH8[8]CO,H, caffeine ^-carboxylic
acid, C6H4O2[i,3,7](CH,)8[8]CO,H, theobromine 8-carboxylic acid, C6HN4O2[3,7]-
(CH.),[8]CO1H. The acids Jose COa when boiled with water (C. 1904, U. 625),
592 ORGANIC CHEMISTRY
Carnine, C7H,N4O+H,O, has been found in meat extracts. It is a powder.
fairly soluble in hot water, which forms a crystalline compound with hydrochloric
acid. Bromine water or nitric acid produces sarcine.
18. TRICARBOXYLIC ACIDS
A. SATURATED TRICARBOXYLIC ACIDS
(d) Triearboxylic Acids with Two or Three Garboxyls attached to the Same
Carbon Atom.
Formation. — (i a) By the action of the halogen fatty-acid esters on the sodium
compounds of malonic esters, CHNa(COaR')a and alkyl malonic esters, R : CNa-
(CO2R')a — e.g. chjorocarbonic ester, chloracetic ester, a-bromopropionic ester,
a-bromobutyric ester, a-bromisobutyric ester, (i b) The tricarboxylic esters,
resulting in this way from sodium malonic ester, still contain a hydrogen of the
CH,-group of malonic ester, which can be acted on anew with sodium and alkyl
iodides. They then yield the same esters which are obtained by starting with
the monoalkyl malonic esters.
(2) By the addition of sodium malonic esters to unsaturated carboxylic esters,
e.g. crotonic ester (B. 24, 2888 ; C. 1897, I. 28).
(3) Also, by the gradual saponification of tetracarboxylic esters, containing
two earboxyl groups attached to the same carbon atom, which split off carbon
dioxide and yield tricarboxylic esters (B. 16, 333 ; 23, 633 ; A. 214, 58).
(4) By heating the best adapted ketone-tricarboxylic esters (B. 27, 797), when
a loss of CO occurs.
Like malonic acid, these tricarboxylic acids readily break down with the
elimination of CO2, yielding succinic acids, e.g. :
(CH3)2CCO,H 1 > (CH3)2CC02H
CH(CO2H), CH2CO2H
Isobutane oo/3-Tricarboxylic unsyra.-Dimethyl Succinic
Acid. Acid. '
For the saponification of tricarboxylic esters consult B. 29, 1867.
Formyl Tricarboxylic Ester, Methane Tricarboxylic Ester Malonic Carboxylic
Ester, CH(CO2CaH8),, m.p. 29°, b.p. 253°, is obtained from sodium malonic
ester, CHNa(COaC2H,)a, and ethyl chlorocarbonate (B. 21, R. 531).
Methane Tricarboxylic Diphenylamidine Diethyl Ester, (C2H.OOC)aCH.-
Of , m.p. 167°, is formed by the combination of sodium malonic ester
XNHC9H5
and carbodiphenylimide, C(NC,H6)2, (Vol. II.) (B. 32, 3176).
Cyanomalonic Ester, CH(CN)(CO2R)2, results from the action of cyanogen
chloride on sodium malonic ester. It volatilizes without decomposition under
greatly reduced pressure. It has a very acid reaction, and decomposes the
alkali carbonates, forming salts, like CNa(CN)(CO,R), (B. 22, R. 567; C. 1901,
I. 675).
Cyanoform, CH(CN)8-f CH3OH (?), m.p. 214°, with decomposition. Sodium
cyanoform is produced when cyanogen chloride acts on malonitrile and sodium
ethoxide (B. 29, 1171).
Ethenyl Tricarboxylic Ester, Ethane Tricarboxylic Ester, Succinic Carboxylic
Ester, C2HsOOC.CHa.CH(COOC2H,)a, is obtained from sodium ethyl, b.p. 278°,
malonate and the ester of chloracetic acid. Chlorine converts it into Chlor ethane
Tricarboxylic Ester, C,HtCl(CO2C2H6)8, b.p. 290°. When heated with hydro-
chloric acid, it yields carbon dioxide, hydrochloric acid, alcohol, and fumade
acid; when hydrolyzed with alkalis, carbon dioxide and malic acid are the
products (A. 214, 44).
Methyl a-Cyanosuccinic Ester, (COaCH,)CH2CH(CN)CO2CH,, is obtained
from methyl cyanacetic ester and chlpracetic ester (B. 24, R. 557).
TRICARBALLYLIC ACID 593
afi-Dicyanopropionic Ester, NC.CH2CH(CN)COaCaH5, b.p.20 169°, is prepared
from formaldehyde cyanhydrin and sodium cyanacetic ester, CNCH«OH4-
NaCH(CN)CO2R=CN.CHaCNa(CN)COaR+H,O. The cyanhydrins of homo-
logous aldehydes and ketones condense similarly : afi-Dicyanisovaleric Ester,
NC.C(CHS)2CH(CN)CO2C2H6, b.p.ia 150°; ap-Dicyanopelargonic Ester, C.HnCH
(CN)CH(CN)COaC2H6, b.p.to 192° (C. 1906, II. 1562), etc.
CHsCHCOaC2H6
Propane aafi-Tricarboxylic Ester, , b.p. 270°.
CH(C01C,Hi)1
The free acid (isomeric with tricarballylic acid), m.p. 146°, breaks down into
carbon dioxide and pyrotartaric acid.
CHaCOaR
Propane afift-Tricarboxylic Ester, , b.p. 273°.
CH,C(C02R)a
CaH6CH.COaR
n.-Butane aafi-Tricarboxylic Ester, , b.p. 278*.
CH(C02R)2
CHaCO2R
n.-Butane afifi-Tricarboxylic Ester, , b.p. 281°.
C2H6C(C02R)t
n.-Butane aa§-Tricarboxylic Ester, (CO2R)CHaCHaCHaCH(COaR)a, b.p.40 203°
(C. 1897, II. 542).
Isobutane aafi-Tricarboxylic Ester, (COaR)C(CH8)a.CH(CO,R)a, b.p. 277°.
(Comp. B. 23, 648).
unsym.-Dimethyl Cyanosuccinic Ester, COaR.CH(CN).C(CH8)a.CO2R, b.p. 186°,
is formed from sodium cyanacetic ester and bromoisobutyric ester (B. 27, R. 506 ;
C. 1899, I. 593, 873)-
a-Cyanoglutaric Ester (B. 27, R. 506).
a-Alkyl a-Carboxyl Glutaric Ester (A. 292, 209 ; C. 1897, I. 28).
a-Cyano-p-isopropyl-glutaric Ester, b.p.g0 195° (C. 1899, I. 1157).
fi-M ethyl Propane aay-TricarboxylicAcid, fi-M ethyl Glutaric a-Carboxylic Ester,
(CO2R)aCHCH(CH,)CHaCpaR, b.p.u 165° is formed from sodium malonic ester
and crotonic ester, and gives, somewhat remarkably, a sodium salt of the con-
stitution (CO2R)2CH.CH(CH8)CHNaCOaR, which, with iodomethane yields
fa-Dimethyl Pro pane aay-Tricarboxylic Ester, (COaR),CHCH(CH8)CH(CH,)COaR,
b.p.10 167°. This substance is isomeric with afi-Dimethyl Propane aay-Tricarboxylic
Acid, (CO2R)jC(CH,)CH(CH,)CHaCOaR, b.p.10 161°, prepared from sodium
methyl malonic ester and crotonic ester. This substance yields a sodium salt
which, with iodomethane gives afiy-trimethyl propane aay-tricarboxylic acid
(B. 33,3731).
^-Dimethyl a-Carboxyl Glutaric Ester, see $3-Dimethyl Glutaric Acid (p. 504).
pj}-Dimethyl a-Cyanoglutaric Ester (C. 1899, I. 252, 532).
(b) Tricarboxylic Acids with the Carboxyl Groups attached to Three
Carbon Atoms. There are many members of this class which are
obtained through loss of CO^ from tetra- and penta-carboxylic acids,
which possess one or two pairs of CO2H-groups attached to the same
carbon atom (B. 24, 307, 2889 ; 25, R. 746 ; C. 1902, 1. no).
Tricarballylic Acid, CH2(CO2H).CH(CO2H).CH2(CO2H,),m.p. 162-
164°, occurs in unripe beetroot, and is found in the deposit in the
vacuum pans during the manufacture of beet sugar. It is prepared
'i) by reduction of aconitic acid (p. 594) (A. 314, 15 ; C. 1903,
[I. 187), and of citric acid (p. 610) ; (z) synthetically from allyl
ribromide, CH?Br.CHBr.CH2Br and KNC, and decomposition of
he tricyanide with aqueous potassium hydroxide : also from a whole
eries of synthetically prepared bodies by cleavage reactions ; (3) from
liallyl acetic acid (p. 306) by oxidation ; (4) from a-acetyl tricar-
>allylic acid ester (p. 612) by hydrolysis (B. 23, 3756) ; (5) from
VOL. i, £ 9
594 ORGANIC CHEMISTRY
propane aafiy- and -aj8j8y-tetracarboxylic ester; (6) from cyanotri-
carballylic ester, the product of combination of sodium cyanosuccinic
ester and bromacetic ester (C. 1902, I. 409) ; (7) from propane
pentacarboxylic ester (p. 622), with loss of CO2 (B. 25, R. 746). It
forms prisms which are easily soluble in water.
The silver salt, CflH6O8Ag8 ; calcium salt, (C6H5O8)2Ca8-f 4H2O, dissolves with
difficulty (C. 1902, I. 409) ; trimethyl ester, C6H6O6(CH8)3. b.p.18 150° ; chloride,
C8H5(COC1)3, b.p.14 140° (B. 22, 2921); anhydride acid, CBH6O6, m.p. 131°
(B 24,2890); triamide, C3H6(CONH2)3, m.p. 206°; amidimide, C6H8O3N2,
m P. 173° (B. 24, 600). Trihydrazide and Triazide, C8H6(CON8)8 (J. pr. Ch. [2]
62,235).
Homologous Tricarballylic Acids :
a-Methyl-, two modifications, ra.ps. 180° and 134° (comp. M. 23, 283);
B-Methyl-, m.p. 164° ; a-Ethyl-, m.p. 147° ; a-n.-propyl, m.p. 151° ; a-isopropyl,
m.p. 161° (B. 24, 288) ; aa^dimethyl-, three modifications (B. 29, 616) ; aa-di-
methyl-, three modifications, m.ps. 143°, 174°, and 206° (C. 1899, I. 826 ; 1900, II.
316 ; 1902, I. 409). These acids are prepared from the corresponding cyano-
tricarballylic acids (the condensation products of sodium cyanosuccinic esters
and a-bromo-fatty acid esters), or from sodium cyanoacetic esters and alkyl
broniosuccinic esters. Trimethyl bromosuccinic ester, however, after reaction
with sodium cyanacetic ester, hydrolysis and cleavage of the product of con-
densation, does not yield the expected trimethyl tricarballylic acid, but oa-
dimethyl butane afa-tricarboxylic acid (CH8)2C(COOH)CH(COOH)CH2CH2COOH
(C. 1902, 1. 409).
aajS-Trimethyl Tricarballylic Acid, Camphoronic Acid, (CH3)2C(CO2H)C(CH3)-
(CO2H).CH2COaH, m.p. 135°, is formed when camphor is oxidized. It is of
fundamental importance in the determination of the constitution of camphor
(Vol. II.). ajSS Butane Tricarboxylic Acid, m.p. 119° (C. 1902, II. 732).
ay$-Pentane Tricarboxylic Acid, Hcemotricarboxylic Acid, two modifications,
m.p. 141° and 175°, is formed by the acid reduction of haematinic acid (p. 595)
(A. 345, 2).
aye-Pentane Tricarboxylic Acid, m.p. 107° (B. 24, 284). Butane fiS-Dicarboxylic
yAcetic Acid, CH8CH(COOH)CH(CH2COOH)2 (M. 21, 879). Methine a-Tri-
propionic Ester, CH[CH(CH8)CO2R]3, m.p. 201°, is prepared from orthoformic
ester, a-bromopropionic ester and zinc (C. 1906, I. 338).
B. OLEFINE TRICARBOXYLIC ACIDS
C02H C02H CO2H
Aconitic Acid, I II, rn.p. 191°, with decomposition
CH o C = CH
into CO2 and itaconic anhydride (p. 516). It is isomeric with tri-
methylene tricarboxylic acid (q.v.), and occurs in different plants ;
for example, in Aconitum napellus, in Equisetum fluviatile, in sugar
cane, and in beet roots. It is obtained by heating citric acid alone
or with concentrated hydrochloric or sulphuric acid (B. 20, R. 254 ;
A. 314, 15).
Aconitic acid has been synthetically prepared by the decomposition ,
of oxalocitric lactone ester (q.v.) with alkali ; by the decomposition \
of the addition product of sodium malonic ester and acetylene di- a
carboxylic ester (J. pr. Ch. [2] 4)9, 20) ; also from cyanaconitic acid c
the product of reaction of cyanacetic ester, oxaloacetic ester anc [
sodium ethoxide (C. 1906, II. 20). It is readily soluble in water, anc „
is reduced by nascent hydrogen to tricarballylic acid.
TETRAHYDRIC ALCOHOLS 595
The calcium salt, (C8H3O6)2Cas+6H2O, dissolves with difficulty; trimethyl
ester, C6H8Ofl(CH8)8. b.p.14 161°, results from the distillation of acetyl citric tri-
methyl ester (B. 18, 1954), and fr°m aconitic acid, methyl alcohol, and hydro-
chloric acid (B. 21, 669).
unsym.-Aconitic Anhydride Acid, C6H4O5 (constitutional formula, see below),
m.p. 76°, is formed when aconitic acid is heated in vacuo to 140°, and when it is
treated with acetyl chloride. When distilled in vacuo it decomposes into CO2 ard
itaconic anhydride (B. 37, 3967). unsym.-Aconitimide Acid, C6H4O4(NH) (consti-
tutional formula, see below), m.p. 191°, is formed from acyl citrimide ester and
alkalis (p. 611); also from /?-anilinotricarballylimide esters and dilute hydro-
chloric acid (B. 23, 3185, 3193)- But the aconitic esters and ammonia yield the
amide of sym.-aconitimide acid, citrazinic acid (formula, see below) (Vol. II.),
which results also from the amide of citric acid and mineral acids (B. 22, 1078,
3054; 23,831 ; 27,3456):
/CO — O /CO . NH XH — CO,
HOaC.CH:C< HOaC.CH:C< HOaC.Cf >NH
XCH2— CO xCHa.CO XCH2-COX
unsym.-Aconitic Anhydride Acid. unsym.-Aconitimide Acid. Citrazinic Acid.
a-(ory)-Methyl Aconitic Acid, HO2C.C(CH8): C(CO2H)CH2CO2HorH9?C.CH.-
CH2C.(CO2H) : CHCOjH, m.p. 159°, is prepared from methyl cyanaconitic ester
(p. 615). It reacts with acetyl chloride to form an anhydride acid, m.p. 51°, which
when heated to 159° decomposes into £ -methyl itaconic anhydride and CO2.
ay-Dimethyl Aconitic Acid, m.p. 164° ; the anhydride-acid, m.p. 74°, is formed
from cyano-ay-dimethyl-aconitic ester (C. 1906, II. 21).
Isoaconitic Ethyl Ester, (C2H6OOC)aCHCH : CHCOOC2H5, is formed when
dicarboxylic glutaconic ester is incompletely hydrolyzed. It is converted by
piperidine into a bimolecular polymer which yields a bimeric glutaconic acid,
m.p. 207" (p. 520) on hydrolysis with hydrochloric acid (B. 34, 677).
Aceconitic Acid and Citr acetic Acid, C,H9O«, are two acids of unknown con-
stitution, isomeric with aconitic acid. They are obtained by the action of sodium
on bromoacetic ester (A. 135, 306 ; comp. B. 27, 3457).
ayS-Butene Tricarboxylic Acid, HOOC.CHaCH(COaH)CH : CHCO2H, m.p. 148°
^C. 1902, II. 732).
&*-Pentene ayS -Tricarboxylic Acid, HOaC.CHaCHaC(CO2H):CH.COaH, is un-
known in the free state. Its anhydride- and imide-acid are identical with the
hcematic acids, obtained from haematin (q.v.) by the ordinary action of chromic
acid. The acids decompose on dry distillation into COa and methyl ethyl maleic
anhydride and imide, respectively (p. 519) (A. 345, i).
VI. TETRAHYDRIC ALCOHOLS AND THEIR OXIDATION
PRODUCTS
Theoretically, there are 15 classes of tetrahydric alcohols, a figure which is
obtained by the combination of the individuals — CH2OH, =CHOH, =COH,
According to the formula, " . etc., where m=3. The
i- lumber of possible classes of oxidation products can be calculated by combining
11 ;he six individuals — CH2OH, =CHOH,^COH,— CHO, =CO, — CO2H, substitut-
ng w=6 in the above equation and subtracting the number 15 of the tetrahydric
ilcohols. Thus, it is found that there are in classes (126— 15) of oxydation pro-
lucts, a number which is diminished when the 10 different classes of trihydroxy-
ddehydes, the 10 classes of trihydroxy-ketones, and the 10 classes of trihydroxy-
arboxylic acids are reckoned as 3 main classes. The more so when the 6 classes
;ach of the dihydroxy-dialdehydes, dihydroxy-diketones, dihydroxy-aldehyde-
ifl cetones, dihydroxy-aldehyde-carboxylic acids, dihydroxy-keto-carboxylic acids
ml ind di-hydroxy-dicarboxylic, acids are considered as constituting 6 main classes.
nirther, the 3 classes each of the monohydroxy-trialdehydes, monohydroxy-
lialdehydediketones^monohydroxy-aldehyde-diketones.monohydroxy-triketones,
596 ORGANIC CHEMISTRY
monohydroxy-dialdehyde-monocarboxylic acids, monohydroxy-monoaldehyde di-
carboxylic acids, monohydroxy-aldehyde-ketone-carboxylic acids, monohydroxy-
diketone-carboxylic acids, monohydroxy-mono-ketone-dicarboxylic acids, and
monohydroxy-tricarboxylic acids, can all be reduced to 10 main classes. There
remains still 15 classes of oxidation products, composed of the fourfold combina-
tion of the three individuals, — CHO, =CO, — CO2H. Thus, the total number of
main classes of the oxidation of the 15 classes of tetrahydroxy-alcohols is 3+6 +
1 0 + 15=34 classes.
These considerations give a clear indication of how little the field of the tetra-
hydroxy alcohols and their oxidation products has been exhausted, since only
15 classes are as yet known.
i. TETRAHYDRIC ALCOHOLS
Ordinary erythritol is best known of the tetrahydric alcohols corre-
sponding with the four tartaric acids (p. 600). By an intramolecular
compensation it, like mesotartaric acid, becomes optically inactive,
and is therefore called i-erythritol. This alcohol and [d-fl] erythritol
were synthetically prepared by Griner in 1893 from divinyl.
Divinyl, or butadiene (p. 88), forms an unstable dibromide, which becomes
rearranged at 100° into two different but stable dibromides. When these are
oxidized by potassium permanganate, the one passes into the dibromhydrin
(m.p. 135°) of ordinary or i-erythritol, whilst the other becomes the dibromhydrin
(m.p. 83°) of [d-fl] erythritol. Potassium hydroxide converts these two dibrom-
hydrins into two butadiene oxides, which, with water, yield the erythritols
corresponding with i- and [d+1] erythritol (B. 26, R. 932 ; A. 308, 333) :
HC.CH2Br (HO)HC.CH2Br (HO)HC.CH,(OH)
^f H -- > I - >"
CH=CH2^ HC.CH2Br (HO)HC.CH2Br (HO)HC.CH2(OH)
CH = CH, \ m.p. 135° i-Erytbritol.
>X HC.CH2Br (HO)HC.CH2Br (HO)HC.CH2(OH)
CH2Br.CH CH2BrCH(OH) CH2(OH)CH(OH)
m.p. 83° [d + l]-Erythritol.
i-Erythritol, Erythroglucin, Phycitol, CH2(OH).CH(OH.)CH(OH).-
CH2.OH, m.p. 126°, b.p. 330°, occurs free in the alga Protococcus
vulgaris. It exists as erythrin (orsellinate of erythritol) in many lichens
and some algae, especially in Roccella Montagnei, and is obtained from
these by hydrolysis with sodium hydroxide or calcium hydroxide.
Erythrin. Erythritol. Orsellinic Acid.
Also, i-erythritol is formed by the reduction of i-erythrose (B. 32, 3677).
Like all polyhydric alcohols erythritol possesses a sweet taste.
By carefully oxidizing erythritol with dilute nitric acid erythrose results. More
intense oxidation produces erythritic acid and mesotartaric acid (p. 604).
i-Nitro-grythritol, C4H6(ONO)24, m.p. 61°, explodes violently when struck.
\-Tetra-acetyl Erythritol, C4H6(OCOCH34), m.p. 85°. i-Erythritol Dichlorhydrin,
C4H8(OH)2Cla, m.p. 125°, is formed from erythritol by the action of concentrated
hydrochloric acid. i-Erythritol Ether, CH^CH CI?CH ' b'p> I38°' Di»*=1'II3»
is formed when potassium hydroxide acts on the dichlorhydrin. It is a liquid
with a penetrating odour, and behaves like ethylene oxide (p. 317). It combines
slowly with water, yielding erythritol, with 2HC1 to the dichlorhydrin, and with
2HNC to the nitrile of dihydroxyadipic acid (B. 17, 1091). Erythritol, in the
TETRAKETONES
597
presence of hydrochloric acid, combines with formaldehyde, benzaldehyde, and
acetone, yielding :
i-Erythritol Diformal, C4H6O4(CH2)2, m.p. 96° (A. 289, 27) ;
i-Erythritol Dibenzal, m.p. 97° ; and
i-Erythritol Diacetone, C4H6O4(C8Ha)2, m.p. 56°, b.p.29 105° (B. 28, 2531).
d-Erythritol, m.p. 88, [a]D=— 4*4°, is obtained by the reduction of erythimlose
(C. 1900, II. 31). 1-Erythritol, [a]D=+4'3°, is similarly obtained from 1-threose
(C. 1901, II. 179)-
[d-f-l]-Erythritol, m.p. 72°, is obtained by the combination of the d- and 1-
compounds. It is identical with the substance obtained from divinyl (p. 596).
[d+Y\-Erytkrito* Ether (B. 26, R. 932). Tetraacetyl-(d+l]-Erythritol, m.p. 53°.
Nitro-tert. -Butyl Glycerol, NO2C(CH2OH)3, m.p. 158°, is formed from nitro-
methane, formaldehyde, and potassium hydrogen carbonate (B. 28, R. 774).
Reduction converts it into hydroxylamino-tert.-butyl-glycerol, HOHN.C(CH2OH)8,
m.p. 140° (B. 30, 3161). See also Dioxyacetone (p. 534).
Penta-erythritol, C(CH2OH)4, m.p. 250-255°, has been prepared by con-
densing formaldehyde and acetaldehyde withlime (C. 1901, II. 1114). See also
vinyl-trimethylene (Vol. II.). Tetraacetyl Penta-erythritol, C(CH2OCOCH3)4, m.p.
84° (A. 276, 58). Penta-erythritol Dibenzal, m.p. 160° (A. 289, 21). Tetra-ethyl
Ether, C{CH2OC2H6)4, b.p. 220° (C. 1897, II. 694). Two Hexyl Erythritols have
been prepared by oxidizing diallyl, CH2=CH.CHa — CH2 — CH=CH2 (p. 90).
Oxidation of hexadiene dibromide, CH3CHBrCH : CHCHBrCH,, produces a
dibromo-di-hydroxyhexane which, when warmed with aqueous sodium hydroxide
yields Hexylene Dioxide, O.CH(CH3)CH.CH..CI1(C113).O, b.p. 177° (B. 35, 1341).
2. TRIHYDROXY ALDEHYDES and 3. TRIHYDROXYKETONES : Erythritose,
Tetrose, is probably a mixture of a trihydroxyaldehyde and a trihydroxyketone
(comp. Glycerose, p. 534 ; B, 35, 2627). It is produced when erythritol is
oxidized with dilute nitric acid. It yields phenylerythrosazone, C4H6O2(N2H-
CeH8)2, m.p. 167° (B. 20, 1090). This probably is also produced from the
condensation product of glycolyl aldehyde (p. 337) (B. 25, 2553 ; 35, 2630).
rf-Erythritose (lavo-rotatory) is formed when d-arabonic acid is oxidized with
OH OH
hydrogen peroxide (B. 32, 3674). 1-Erythritose, HOC.C — CCH2OH (dextro-rotatory)
H H
results from the oxidation of 1-arabonic acid, or by the decomposition of
1-arabinose oxime through the nitrile, by loss of hydrocyanic acid (B. 32, 3666 ; 34,
1365) (comp. also the decomposition of d-dextrose, p. 618). Similarly, by oxidation,
H OH
or by the hydrocyanic acid reaction, 1-xylose yields l-threost, HOC-<j>— CCH,OH
OHH
stereosomeric with erythrose. 1-Erythritose and 1-threose yield the same osa-
zone (B. 34, 1370). Erythrulose is obtained from erythritol by means of the
Sorbose bacterium. It yields d-erythritol on reduction, and is probably a ketose.
Methyl Tetrose, CH3[CHOH]3CHO, is obtained from rhamnose oxime and acetic
anhydride, and also from rhamnonic acid and hydrogen peroxide, iosazone, m.p.
173°. Benzyl Phenylhydrazone, m.p. 97°, when oxidized with nitric acid, yields
d-tartaric acid ; bromine water produces methyl tetronic acid (B. 29, 138 ; 35,
2360).
4. HYDROXYTRIKETONES : ^-Methyl-heptane-^-o\-2^t6-tnonet
aldol of diacetyl, CH3COC(OH)(CH3).CH2CO.COCH3, b.p.18 128° (p.349)-
5. TETRAKETONES: Tetra-acetyl Ethane, (CH3CO)2CH— CH(CO-
CH3)2, is obtained from sodium acetyl acetone by means of iodine or
by electrolysis (p. 350).
Oxalyl Diacetone, CH3COCH2.COCO.CH2COCH3, m.p. 121°, and
are formed from oxalic ester acetone or methyl ethyl ketone and sodium
598 ORGANIC CHEMISTRY
ethoxide. It consists of yellow crystals, which remain yellow on
fusion and form yellow solutions. Oxalyl diacetone give a dipyrazole
derivative with phenylhydrazine (A. 278, 294).
Methenyl Bisacetyl Acetone, (CH3CO)2CH.CH=C(COCH3)2, is ob-
tained from ethoxymethylene acetyl acetone (p. 536) by the addition
of acetyl acetone.
6. TRIHYDROXY-MONOCARBOXYLIC ACIDS.
Trihydroxybutyric Acid, rac.-Erythronic Acid, Erythrogluctc Acid, CH2OH-
[CHOH],CO2H, is obtained by the oxidation of erythrytol and mannitol (2) (B. 19,
468). It is a crystalline deliquescent mass. d-Erythronic Acid (Uevo-rotatory)
is formed by the oxidation of d-erythritose with bromine ; from d-fructose with
HgO ; and from the dextrosone (p. 629), with bromine (C. 1902, I. 859 ; II. 109).
d-Erythronic Lactone, m.p. 103°. l-Erythronic Acid (dextro-rotatory) is prepared
from 1-erythrose and bromine water.
l-Erythronic Lactone, m.p. 104° (B. 34, 1362).
i&c.-Erythr onic Lactone, m.p. 91°. is obtained from y-hydroxycrotomc lactone
(p. 398), and permanganate. The y-ethyl ether oi erythronic acid, C2H6O.CH2CH-
OH.CHOH.CO,H, m.p. 91°, is similarly obtained from y-ethoxycro tonic acid
(c. 1905, 1. 1138; 11.457.
Trihydroxyisobutyric Acid, (CHsOH)a.C(OH)CO8H, m.p. 116°, is obtained
from glycerose and HNC (B. 22, 106).
afiy-Trihydroxyvaleric Acid; afi-Dihydroxy-y-valerolactone, CH3CHCH(OH)-
CH(OH)COO, m.p. 100°, is formed by oxidation of a-angelic acid lactone (p. 398)
by permanganate (A. 319, 194). This dehydroxyvalerolactone must be looked
on as being the racemic form of the Methyl Tetronic Acid Lactone, m.p. 121°, [a]D =
—47-5°, obtained by oxidation of methyl tetrose (p. 597) by bromine water,
afiy-Trihydroxyvaleric Acid is specially characterized by its phenylhydrazide,
m.p. 169°, and its brucine salt (B. 35, 2365).
1,3,4-Trihydroxyvaleric Acid ; the 1,4-0*1^1 of this acid, the (3-Hydroxy-
tetrahydrofurfurane a-Carboxylic Acid, OCH2.CH(OH)CH2CHCOOH, m.p. 110°, is
formed from the corresponding malonic acid derivative when it is heated with
water (B. 37, 4544)-
The corresponding 1,4-imide — p'-Hydroxypyrrolidine a-Carboxylic Acidf
P'-Hydroxyproline, HNCH2CH(OH)CH2CHCOaH, a-form, m.p. 26°, with decom-
position, 6-fonn 250°, with decomposition, is formed from a§-bromo-chloro-y-
valerolactone, ClCH,CH.CHa.CHBr.COO. The a-form yields a slightly soluble
copper salt. The last named acid, like the i,4-oxide (see above) is prepared
from the synthetic 8-chlorovalerolactone carboxylic ester (p. 599) by the action
of ammonia. It has not yet been determined whether the synthetic hydroxy-
proline is the racemic form of the natural Hydroxyproline, m.p. 270° with decom-
position [a]^= — 81-04°, which is obtained by the hydrolysis of gelatin. Both
compounds possess a sweet taste, are reduced by hydriodic acid and phosphorus to
proline (p. 542), and are very stable towards hydrolytic agents (B. 41, 1726).
7. DIHYDROXYKETO-MONOCARBOXYLIC ACIDS.
ay-Diethoxy-acetoacetic Ester, C2H5O.CH1CO.CH(OC2H6).CO2C2H5, b.p.14
132°, is prepared from ethoxychloracetoacetic ester (p. 545) and sodium ethoxide
(A. 269, 28).
8. HYDROXYDIKETO-CARBOXYLIC ACIDS.
Acetyl Acetone Chloral, CCl8.CH(OH)CH2CO.CHaCOCH8, m.p. 78°, is a de-
rivative of heptane-2-ol-4,6-dione-l-acid. It is prepared from chloral and acetyl
acetone (C. 1898, II. 704).
9- TRIKETO-MONOCARBOXYLIC ACIDS.
The fi-phenylhydrazone of afiy-Triketo-n.-valeric Acid, m.p. 206°, is prepared
from sodium acetone oxalic acid and diazobenzene chloride (A. 278, 285).
SUCCINIC ACID DERIVATIVES 599
Diacetyl Pyroracemic Acid, (CH3CO)2CHCOCO2H, provides a derivative
cyaniminomethyl acetyl acetone (CH3CO)2CH.C(NH)CN, which is prepared from
acetyl acetone, cyanogen and a little sodium ethoxide. Aqueous sodium hydroxide
decomposes it into sodium cyanide and cyanacetyl acetone (p. 547). It combines
with a further quantity of acetyl acetone to form dicyano-diacetyl-acetone and
similarly with acetoacetic ester and malonic ester (A. 332, 146).
Derivatives of pyruvylpyruvicacid,CHtCOCO.ClizCOCOOlI, are formed from
pyroracemic ester and aromatic amines, e.g., CH8C(NC,H5)COCHaC(NC6H6)COa-
C2H6, which is decomposed by sulphuric acid into CHaC^NCgHgJCOCHjCOCO,-
CjjHg, m.p. 140 (C. 1902, I. 1320). Homopyruvyl Pyruvic acid, Heptane-^fo-
trione-j-acid, provides derivatives such as the methoxime ester, C2H6C(NO.CH,)-
COCH2COCO2R ; methyl ester, m.p. 80° ; ethyl ester, m.p. 41°, which are prepared
from the methoxime of acetyl propionyl (pp. 349, 354), oxalic ester, and sodium
ethoxide (B. 38, 1917).
ay-Diacetyl Acetoacetic Acid, CHSCOCH2COCH(COCH3)CO2H. The lactone
of the 8-aci- or -enol-form of this hypothetical acid, Dehydr acetic Acid, 6-Methyl-
CO— O— CCH,
5-aceto-pyronone, \\ , m.p. 108°, b.p. 269°, is formed by
CHjCO.CH.CO.CH
boiling acetoacetic ester under a reflux condenser ; from dehydracetocarboxylic
acid (A. 273, 186) by evaporation with aqueous sodium hydroxide ; from acetyl
chloride and pyridine ; and from triacetic acid (p. 548) by heating with acetic
anhydride and sulphuric acid (C. 1900, II. 625). It is isomeric with isodehydr-
acetic acid (p. 571 ). The constitution of dehydracetic acid has been demonstrated
by Feist (A. 257, 261 ; B. 27, R. 417). Hydriodic acid produces dimethyl pyrone,
I ° 1
CH,.C:CH.CO.CH.C.CH, (?.».).
10. DIHYDROXY-DICARBOXYLIC ACIDS.
A. Malonie Acid Derivatives, yS Dihydroxypropyl Malonic Acid, CH,(OH)CH-
(OH)CH2CH(CO2H)a; lactone ester, S-hydroxy-y-valerolactone carboxylic ester,
CH2(OH).CHCHaCH(CO2C2H,)COO, a syrup, is formed from 8-chloro-y-valero-
lactone carboxylic ester, the product of condensation of epichlorhydrin (p. 532) and
malonic ester. The lactone ester and alcoholic ammonia form y-S-Dihydroxy-
propyl Malonamide, m.p. 140° (B. 35, 197) ; comp. also B. 38, 1939)- Hydro-
lysis of the chlorovalerolactone ester causes loss of CO 2 and production of chloro-y-
valerolactone, together with the dilactone OCHaCH.CHa.CH.CO, m.p. 180° ;
b io
bromine produces a-bromo-S-chloro-y-valero-lactone ester (B. 40, 301).
CHaCHa.CHa, XHaCHaCH,
Di-(D-hydroxypropyl Malonic Acid Lactone, \ "/> C<Q I ,
m p. 106°, is formed from diallyl malonic acid (p. 522), and hydrobromic acid
(A. 216, 67).
B. SUCCINIC ACID DERIVATIVES.
Tartaric Acids or Dihydroxyethylene Succinic Acids. — Tartaric acid
is known in four modifications; all possess the same structure
and can be converted into one another. They are : (i) Ordinary or
Dextro-tartaric acid. (2) Lcevo-tartaric acid. These two are distin-
guished from each other by their equally great but opposite molecular
rotatory power. (3) Racemic Acid, paratartaric acid, or [d+l]-tartanc
acid. This is optically inactive, but can be resolved into dextro-
and Icevo-tartaric acids, from which it can again be reproduced by their
union. (4) Mesotartaric acid, antitartaric acid, \-tartaric acid, is
optically inactive and cannot be split into other forms. The isomensm
6oo ORGANIC CHEMISTRY
of these four acids was exhaustively considered in the introduction.
According to the theory of van 't Hoff and Le Bel, it is attributable
to the presence of two asymmetric carbon atoms in the dihydroxy-
ethylene succinic acid. A compound containing one asymmetric carbon
atom may occur in three modifications — a dextro-form, a laevo-form,
and, by union of these two, an inactive, decomposable [d-fl] modifica-
tion. If the same atoms or atomic groups are joined to two asymmetric
carbon atoms, — that is, if the compound be symmetrically constructed,
like hydroxyethylene succinic acid, — then in addition to the three
modifications capable of forming a compound with one asymmetric
carbon atom there arises a fourth possibility. Should the groups
linked to the one asymmetric carbon atom (viewed from the point
of union of the two asymmetric carbon atoms) show an opposite
arrangement from that of the groups attached to the second asymmetric
carbon atom, then an inactive body will result by virtue of an internal
compensation. The action on polarized light occasioned by the one
asymmetric carbon atom is equalized by an equally great but oppositely
directed influence exerted by the second asymmetric carbon atom.
(Sea also B. 35, 4344.)
Therefore, the four symmetrical dihydroxysuccinic acids can be
represented by the following formulae, to which must be ascribed a
spacial significance as basis (p. 32) :
COaH CO.H CO.H
H— *<>-OH HO— *C— H H— *(>-OH
HO— *A-H H— *C— OH * H— *C— OH
CO,H CO,H C08H
(i) Dextrotartaric Add. a) Laevotartaric Acid. (3) Mesotartaric Acid.
d-Tartaric acid+1-tartaric acid=U) Racemic Acid.
The configuration of d-tartaric acid, as represented on p. 646,
follows in consequence of the formation of this acid from the oxidation
of methyl tetrose, the decomposition product of rhamnose.
Historical. — Scheele in 1769 showed how this acid could be isolated from argol.
Kestner in 1822 discovered racemic acid as a by-product in the manufacture of
ordinary tartaric acid, and in 1826 Gay-Lussac investigated the two acids. He and
later Berzelius (1830) proved that ordinary tartaric acid and racemic acid pos-
sessed the same composition, and this fact led Berxelius to introduce the term
isomerism into chemical science (p. 25). Biot (1838) showed that a solution of
ordinary tartaric acid rotated the plane of polarized light to the right, whereas the
solution of racemic acid proved to be optically inactive, and was without action
upon the polarized ray. Pasteur's classic investigations (1848-1833) demonstrated
how racemic acid could be resolved into dextro- and lavo-tartaric acid, and be again
re-formed from them. In addition to lasvo-tartaric acid, Pasteur also discovered
inactive or mesotartaric acid, which cannot be resolved. Kekule in 1861 and,
independently of him, Perkin, Sr.t and Duppa synthesized racemic acid and meso-
tartaric acid from succinic acid, derived from amber, through the ordinary
dibromosuccinic acid. In 1873 Jungfleisch obtained racemic acid and meso-
tartaric acid from synthetic succinic acid, and also the other two tartaric acids
derivable from racemic acid. Van 't Hoff in 1874 and, independently of him,
Le Bel referred the isomerism of the four tartaric acids to the presence of two
asymmetric carbon atoms in symmetrical dihydroxyethylene succinic acid.
KekuU and Anschutx in 1880 and 1881 found that when racemic acid was oxidized
it yielded fumaric acid, and that inactive or mesotartaric acid gave maleic acid.
RACEMIC ACID
601
The oxidant was potassium permanganate. This reaction directly linked the
isomerism of the tartaric acids to the isomeris
isomerism of the two unsaturated acids
fumaric acid and maleic acid.
(i) Racemic Acid, Paratartaric Acid, C4H6O6-f-H2O, m.p. 206°
with decomposition (anhydrous), is sometimes found in conjunction
with tartaric acid in the juice of the grape, and is formed in the pre-
paration of ordinary tartaric acid, when the solution is evaporated
over a flame, especially in the presence of alumina.
Racemic acid appears (i) in the oxidation of mannitol, dulcitol
and mucic acid with nitric acid, as well as when fumaric acid (B. 13,
2150), sorbic acid, and piperic acid are oxidized by potassium per-
manganate (B. 23, 2772). It is synthetically obtained (2) from
glyoxal by means of hydrocyanic and hydrochloric acids (together
with mesotartaric acid, B. 27, R. 749), and (3) from isodibromo- and
(together with mesotartaric acid) from dibromosuccinic acid, by the
action of silver oxide (pp. 501, 604) ; (4) together with glycollic acid
(comp. the pinacone formation, p. 313), when glyoxylic acid is
reduced with acetic acid and zinc ; (5) by heating desoxalic acid with
water to 100°, when carbon dioxide is split off.
Ethyl alcohol, which can be synthesized in various ways, constitutes
the parent substance for the first four syntheses. In the fifth synthesis
carbon monoxide serves for that purpose.
SYNTHESIS OF RACEMIC ACID
CH2OH
I
CH,
COaH
Succinic
Acid.
C02H
C02H
CO,H
CHBr
CHBr
CH
' 1
CHa
> 1 3
CHBr
' CH
COaH
CO2H
CO,H
Monobromo-
Ord. Dibromo-
Fumaric
succinic Acid.
succinic Acid.
Acid.
CHO
— 7-
CO,H
V^IN
CH.OH
^\^aXA
CH.OH
> f i
I>^
^ i
CHO
'->
CHO
CH.OH
CH.OH
CN
CO,H
Glyoxal.
Glyoxalic Acid.
COaNa COaCaH6
Racemic Acid.
(C08CaH6), (COaH)t
COH COH
CO —
-> HCOaNa ->-
COaNa COaCaH6
CHOH CH.OH
CO,CaHs CO.H
Carbon
Sodium
Sodium
Desoxalic Acid.
Monoxide.
Formate.
Oxalate.
602 ORGANIC CHEMISTRY
Racemic acid is also produced when equal quantities of concen-
trated solutions of dextro- and Isevo-tartaric acids are mixed (B. 25,
1566), and together with mesotartaric acid when ordinary tartaric
acid is heated with water to 175°.
Properties. — Racemic acid crystallizes in rhombic prisms which slowly
effloresce in dry air. It is less soluble (i part in 5-8 parts at 15°) in water than
the tartaric acid, and has no effect on polarized light. Potassium permanganate
oxidizes it to oxalic acid, and hydriodic acid reduces it to inactive malic and
ethylene succinic acids. Its salts closely resemble those of tartaric acid, but do
not show hemihedral faces ; the acid potassium salt is appreciably more soluble
than cream of tartar; calcium salt, C4H4O6Ca+4H2O, dissolves with more
difficulty than the corresponding salts of three other tartaric acids. Dilute
acetic acid and ammonium chloride do not dissolve it. It is formed on mixing
solutions of calcium dextro- and laevotartrates ; barium salt, C4H4O8Ba+2jH2O,
or 5H,O (A. 292, 311). Racemic changes of the racemates (B. 32, 50, 857).
Optical Kesolution of Racemic Acid. — When Pasteur was
studying racemic acid he discovered methods for the decomposition
of optically inactive bodies into their optically active components,
which were briefly considered in the introduction (p. 57) :
(i) Penicillium glaucum, growing in a racemic acid solution,
destroys the dextro-tartaric acid, leaving the 1-tartaric acid un-
attacked.
(20) From a solution of sodium ammonium racemate the unaltered
salt, withput hemihedral faces, separates above +28° (B. 29, R. 112).
When the crystallization takes place below +28°, large rhombic crystals
form, some of which show right, others left hemihedral faces. Re-
moving the similar forms, or by testing a solution of the crystals with
a solution of calcium dextro-tartrate (A. 226, 193), the former will be
found to possess dextro-rotatory power and yield common tartaric
acid, whereas the latter yield the laevo-acid.
(zb) A solution of cinchonine racemate yields, on the first crystalliza-
tion, the more sparingly soluble laevo-tartrate. If only- half as much
cinchonine, as is necessary for the production of the acid salt, be intro-
duced, then two-thirds of the calculated quantity of cinchonine laevo-
tartrate will separate (B. 29, 42). Quinicine dextrotartrate is the first
to crystallize from a solution of quinicine racemate.
Esters of Racemic Acid : Dimethyl ester, m.p. 85°, b.p. 282°, is produced
from racemic acid, methyl alcohol, and HC1. It can be made by fusing together
the dimethyl ester of dextro- and laevo-tartaric acids. It is obtained pure by
distillation under reduced pressure. In vapour form it dissociates into the
dimethyl ester of the dextro- and laevo-tartaric acids (B. 18, 1397 ; 21, R.
643).
Diacetyl Racemic Anhydride, (C,H3O2)2C4H1OS, m.p. 123° (B. 13, 1178).
Dimethyl Diacetyl Racemic Ester, (C2H3O2),C4H2O4(CH8),, m.p. 86°, results
from the action of acetyl chloride on the dimethyl ester ; and upon evaporating
the benzene solution of the dimethyl-1- and d-diacetyl tartaric esters (A. 247, 115).
Nitrile of Diacetyl Pyroracemic Acid, CH3CO.OCH(CN).CH(CN)O.COCH8, m.p. 97°,
is produced together with the nitrile Qi diacetyl mesotartaric acid, when acetic
anhydride acts on the liquid portion of the additive product resulting from
HNC and glyoxal in alcohol (B. 27, R. 749).
Imides: Methyl-, ethyl-, and phenyl-imides, m.p. 157°, 179°, and 235° (B. 30,
3040). The anil of diacetyl racemic acid, m.p. 94°, results when PC16 acts
on the anilic acid, and when the Anils of d- and \-Diacetyl Tartaric Acids, m.p.
126°, combine (privately communicated by Anschiitz and Reitter).
ORDINARY TARTARIC ACID 603
(2) Dextro-rotatory or Ordinary Tartaric Acid (Acidum tartaricum),
m.p. 167-170° (B. 22, 1814), is widely distributed in the vegetable
world, and occurs principally in the juice of the grape, from which it
deposits after fermentation in the form of potassium hydrogen tartrate
(argol). It results on oxidizing methyl tetrose, saccharic acid, and
lactose with nitric acid.
Ordinary tartaric acid crystallizes in large monoclinic prisms,
which dissolve readily in water (i part in 076 parts at 15°) and
alcohol, but not in ether. Its solution rotates the ray of polarized
light to the right, but a very concentrated aqueous solution at low
temperatures turns it to the left (B. 32, 1180). When it is heated
with water to 165° it changes mainly to mesotartaric acid ; at 175°
the racemic acid predominates. Also, boiling with concentrated
aqueous alkali converts d-tartaric acid partially into racemic and
mesotartaric acids (B. 30, 1574). It also forms racemic acid when it
is brought together with a concentrated solution of 1-tartaric acid.
Pyroracemic and pyrotartaric acids (p. 50) are products of its dry
distillation.
^ When gradually oxidized, d-tartaric acid becomes dihydroxyfumaric
acid (p. 607), dihydroxytartaric acid, and tartronic acid (p. 549) ;
stronger oxidizing agents decompose it into carbon dioxide and formic
acid.
Hydriodic acid reduces it to d-malic and etlrylene succinic acids.
d-Tartaric acid is applied in dyeing or colouring, as an ingredient of
effervescing powders, and as a medicine. Nearly all of -its salts meet
with extended uses.
Salts. Tartrates. — The normal potassium salt, C4H4O6K2+|H2O, is readily
soluble in water ; from it acids precipitate the salt, C4H5O6K, which is not very
soluble in water, and constitutes natural argol (Cremor tartari) ; potassium sodium
tartrate, C4H4O6KNa+4H2O (Seignette salt], crystallizes in large rhombic prisms
with hemihedral faces; -sodium ammonium salt, C4H4OaNa(NH4)-{-4H2O, is
obtained from sodium ammonium racemate ; calcium salt, C4H4O6Ca-fH2O, is pre-
cipitated from solutions of normal tartrates, by calcium chloride, as an insoluble,
•crystalline powder. It dissolves in acids and alkalis, and is reprecipitatecl as
a jelly on boiling — a reaction serving to distinguish tartaric from other acids.
(See also Calcium Racemate.)
Lead salt, C4H4O,Pb. Copper salts are not precipitated by alkali hydroxides
in presence of tartaric acid. When cupric hydroxide is dissolved in tartaric
acid and aqueous alkali, double salts are formed, such as cupric sodium ditartrate,
C4H2O8CuNa2+C4H2O6Na4-fi3H2O (B. 82,2347). A solution of copper sulphate,
rochelle salt, and sodium hydroxide is known as Fehling's solution, and is employed
in the quantitative analysis of certain sugars (p. 628).
Tartar Emetic. — Potassio-Antimonyl Tartrate, Tartarus emiticus, Tartarus
stibiatus, COOK.CHOH.CHOH.COOSbO+£H20, or C4H4O6:SbOK+iHaO, or
C02K[CHOH]2COOSb<^>Sb.OCO[CHOH]2.COOK+H20 (B. 16, 2386), is pre-
pared by boiling cream of tartar with antimony oxide and water. It crystal-
lizes in rhombic octahedra, which slowly lose their water of crystallization on
exposure and fall to a powder. It is soluble in fourteen parts of water at 10°.
Its solution possesses an unpleasant metallic taste, and acts as an emetic. See
B. 29, R. 84 ; 28, R. 463, for the corresponding arsenic compound.
Dextro-tartaric Acid Esters, ROOC.CH(OH)CH(OH).COOR (comp. Racemic
Esters), are obtained as follows: the acid is dissolved in methyl or ethyl
alcohol, hydrochloric acid gas is passed through the solution, and the liquid
is distilled under diminished pressure. PClg converts them into esters of chloro-
'ic acid (p. 605) and chlorofumaric acid. The esters constitute the first
mal
604 ORGANIC CHEMISTRY
homologous series of optically active substances, of which the rotation Of the
plane of polarized light was investigated (Anschutx and Pictet, B. 13, 1177;
comp. B. 27, R. 5«. 621, 7*5. 7*9', B. 28, R. 148 ; C 1898, II. 17) Dimethyl
Ester, m.p. 48°, b.p.760 280° [a]Dto=*+ 2*16. Diethyl Ester, fluid, b.p.760 280°
[a]Dto==_j_266. Di-n.-propyl Ester, fluid, b.p. 7,0 303° [a]Dto = +i2'44-
The action of iodo-alkyls and silver oxide is to produce ethers by substitution
of the alcoholic hydroxyl groups of the tartaric esters. Thus, d-tartaric ester
is converted by iodomethane and silver oxide into d-Dimethoxysuccimc Dimethyl
Ester, CH302C.CH(OCH8)CH(OCH8).C02CH8, m.p. 51°. b.p.lt 132°, which, on
hydrolysis with barium hydroxide solution, yields d-Dimethoxysuccinic Acid,
m.p. 151°. These ether-esters are also produced from silver tartrate and iodo-
alkyls. But if sodium ethoxide is present during reaction between tartaric esters
and iodo-alkyls there results a mixture of sym.- and unsym.-dialkoxysuccinic
esters (p. 566), which can also be produced by the action of sodium ethoxide on
sym.-dibromosuccinic ester (C. 1900, I. 404 ; 1901, II. 401).
Mono- and Di-formal Tartaric Acids.
3 /OCH— CHOV
and CH,< | )>CHt
;H.CO»H NDCO coo '
(C. 1903, I. 136).
Diacetyl d-Tartaric Anhydride (C2H8O)2C4H2O3, m.p. 135°, is prepared by
treatment of tartaric acid with acetic anhydride and a little sulphuric acid..
Pyridine acetate at o° produces the pyridine salt of hydroxymaleic anhydride
(p- 565). Diacetyl Tartaric Dimethyl Ester, m.p. 103°. Diacetyl Tartaric Dianilidef
m.p. 214° (A. 279, 138). Diacetyl d-Tartaric Anil ; see Diacetyl Racemic Anil
(p. 602). Other imides (B. 29, 2710).
Nitrotartaric Acid, Dinitrotartaric Acid, (NO,O)aCaHa(CO2H)2, is obtained
from tartaric acid by the action of nitric and sulphuric acids. It dissolves
readily in alcohol and ether, and is insoluble in benzene and chloroform.
[a]Dao=* 4- 1 3' 5° in methyl alcohol. In aqueous solution the substance decomposes
into dihydroxytartaric acid (p. 607), COaH.C(OH)2.C(OH)2CO2H, which breaks
down further into COa and tartronic acid. Dinitrotartaric Esters: Dimtthyl
Ester, m.p. 75° ; diethyl ester, m.p. 27°. Mononitrotartaric esters, ROaC.CH(ONOa)-
CH(OH).CO2R; dimethyl ester, m.p. 97°; diethyl ester, m.p. 47°. Both the
series of compounds are formed together when tartaric esters are treated with
nitric and sulphuric acids (C. 1903, I. 627 ; B. 36, 778).
(3) Laevo-Tartaric Acid, m.p. 167-170°, is very similar to the
dextro-variety, and only differs from it in rotating the ray of polarized
light to the left. Their salts are very similar, and usually isomorphous,
but those of the laevo-acid exhibit opposite hemihedral faces.
The dimethyl ester has the same melting and boiling points as the
dimethyl ester of d-tartaric acid (see above) ; comp. also racemic
acid esters (p. 602). In the description of racemic acid the method
by which 1-tartaric acid could be obtained from it was exhaustively
considered (p. 602). In concentrated solution it combines with
d-tartaric acid and yields racemic acid.
(4) Inactive Tartaric Acid, Mesotartaric Acid, Antitartaric Acid,
is obtained when parasorbic acid and erythritol are oxidized with
nitric acid, or (together with racemic acid) when dibromosuccinic acid
is treated with silver oxide (p. 601) ; and maleic acid or phenol with
potassium permanganate (B. 24, 1753). It is most readily prepared
by heating common tartaric acid with water to 165° for two days. It
contains one molecule of water of crystallization.
Calcium Salt, C4H4O,Ca+3HaO (A. 226, 198); barium salt, C4H4O,Ba-
+HaO (A. 292, 315); dimethyl ester, m.p. 111°; diethyl ester, m.p. 54%
GLUTARIC ACID DERIVATIVES 605
b.p.u 156° (B. 21, 51?)- Mesotartaronitrile, CN.CH(OH).CH(OH)CN, rn.p. 131°
with decomposition, is produced by the addition of hydrocyanic acid to glyoxal,
dissolved in a.lcohol. Diacetyl Mesotartaronitrile, m.p. 76° (B. 27, R. 749)
Chbromalic ksM,a-Chloro-8-kydro»y-succinic Ester, HO2C.CH(OH)CHC1 CO H
m.p. 143°, and Bromomalic Acid, m.p. 134°, are obtained from fumaric or maleic
acid by the addition of HC1O or HBrO (in the form of chlorine or bromine
water). When heated they decompose into water and chloro- and bromo-maleic
acids ; when boiled with water they break down into CO2l the halogen acid,
aldehyde, and a mixture of racemic and mesotartaric acid . The acids are optically
inactive. If, however, d-tartaric ester is treated with PC18 or PBr3, l-chloromalic
ester and \-bromomalic ester result (B. 28, 1291 ; A. 348, 273).
/CH.CO2H
Elhylene Oxide Dicarboxylic Acid, Fumaryl Glycidic Acid, O<; I m p
XCH.COZH'
203°, is prepared from chloro- and bromo-malic acid by aqueous sodium
hydroxide ; HBr and HC1 regenerate the original acids. When boiled with water
it breaks down into racemic and mesotartaric acids ; dimethyl ester, m.p. 73° ;
diamide, m.p. 225° with decomposition ; dichloride, m.p. «n°, bo „« 00-01*
(A. 348, 299).
Diaminosuccinic Acid, CO2H.CH(NH2)CH(NH2).CO2H, is formed when
the diphenylhydrazone of dioxosuccinic acid (p. 608) is reduced with sodium
amalgam. The one acid corresponds with mesotartaric acid (p. 604), the other with
racemic acid (p. 601), as has been proved by conversion into these acids ; diethyl
ester, b.p.1B 160-165°. Diacetyl Diaminosuccinic Diethyl Ester, m.p. 180° (B. 38,
1589). Reaction with one molecule of nitrous acid produces Hydroxyamino-
succinic Acid, HO2C.CH(NH2)CH(OH).COaH, m.p. 314-318° (C. 1905, I. 1890;
see also A. 348, 307).
Dianilinosuccinic Ester, CO2C2H6.CH(NHC6HB)CH(NHC6H6).CO2C2H6, m.p.
149°, is obtained from dibromo- and isodibromo-succinic ester and alcoholic
aniline heated to 100° (B. 27, 1604).
/CH— CO2C2H5
Iminosuccinic Monoethyl Ester, NH<f , m.p. 98° is prepared
\;H.C02H.
from iminosuccinic monoester amide, a product of the reaction of alcoholic
ammonia and dibromosuccinic ester (B. 25, 646).
Azinsuccinic Ester, (CO2C2H6)2C2H2.N2.C2H2(CO2C2H8), is obtained from
diazoacetic ester ; an isomeric ester is obtained from diazosuccinic ester (B. 29,
763).
.
Oxycitraconic Acid, O<( | , decomposes at 162°. It is formed when
XCH.CO2H
a-Chlorocitramalic Acid, m.p. 139°, the addition product of HC1O and citraconic
acid, is treated with alkali hydroxide. Hydrochloric acid changes it to fi-Chloro-
citramalic Acid, m.p. 162° with decomposition (A. 253, 87).
CH2 - CO\
Hydroxyparaconic Acid, >O, m.p. 104°, is prepared from
H02C.C(OH).CH/
itaconic acid (p. 515) and potassium permanganate.
CH8.C(OH).CO2H
Dimethyl Racemic Acid, +H2O, m.p. 178° with decomposition,
CH8.C(OH)CO2H
is formed (i) from pyroracemic acid (p. 407) by reduction (B. 25, 397), and (2) from
diacetyl (p. 349) by the action of HNC and hydrochloric acid (B. 22, R. 137).
C. Glutaric Acid Derivatives.
ap-Dihydroxyghttaric Acid, HO2C.CH(OH)CH(OH)CH2.CO2H, m.p. 158°, is
formed from the bromine addition product of glutaconic acid, or from the latter
by permanganate. An optically active form of this acid has been obtained by
the break-down of metasaccharopentose (p. 620) (B. 38, 3625).
ay-Dihydroxyglutaric Acid, HO2C.CH(OH)CHaCH(OH)CO2H, m.p. 120°;
lactone acid, m.p. 165°, is formed from ay-dihydroxypropane aay-tricarboxylic
acid (the oxidation product of isosaccharine, p. 620) by loss of CO3 (B. 18, 2576 ;
38, 3624).
606 ORGANIC CHEMISTRY
ay-Dihydroxy-ay-dimethyl-glutaric Acids, 8
exists in two modifications, both of which are prepared from acetyl acetone and
hydrocyanic acid (B. 24, 4006 ; 25, 3221 ). The one, m.p. 98°, is obtained in enantio-
morphous crystals from ether ; the other readily passes into the lactonic acid>
m p 90°, which, when heated, forms a dilactone, m.p. 105°, b.p. 235°, ap-Dihydroxy-
yy-dimethyl-glutaric Lactonic Acid (p. 57°) '• ay-Dihydroxy-fip-dimethyl-glutaric
Acid, (CH3)2C[CH(OH)CO2H]2; lactonic acid, m.p. 146° (C. 1901, II. 109);
ay-Dihydroxy- and py-trimethyl-glutaric Acid (B. 28, 294°)-
D. Adlplc Acid Derivatives and Higher Homologues.
aa-Dihydroxyadipic Acid, HO2C.CH(OH)CH2CH2CH(OH)CO2H, exists in
two forms which are produced from the corresponding aa-Dibromadipic Acids,
m.ps. 139° and 193°, which occur together after the bromination of adipic acid
chloride (C. 1908, I. 2021). The racemic form, m.p. 146°, is resolved by means
r- -
of cinchonidine, and when heated yields a dilactone, OCOCHCH2CHaCHCOO,
m.p. 134° ; meso-form, m.p. 173°, is not resolvable, and when heated gives a
lactone lactide.
CH2CH(NH2)C02H
aai-Diamino adipic Acid, \ , decomposes at 275°, is pre-
CH2CH(NH2)C02H
pared by decomposition of ethylene bis-phthalimidomalonic ester, a product
of reaction of ethylene bromide and sodium phthalimidomalonic ester (p. 550).
Similarly, aja^-diaminopimeUc acid is formed from trimethylene bis-phthalimido-
malonic ester (C. 1908, II. 682).
NH2.CHCH2CO2H
BB,-Diaminoadipic Acid, +H2O.
NH2.CHCH2CO2H
, OC
The dilactam, OCCH2CH(NH)CH(NH)CH2CO, m.p. 275°, is formed by heating
muconic acid or muconic amide (p. 522) with ammonia to 135-150° ; also by reduc-
tion of dicyanodimalonic ester, (RO2C)a.CHC(NH).C(NH)CH(CO2R)2 (p. 655),
and subsequent hydrolysis and abstraction of CO2 (B. 36, 172).
aa,i-Diaminosuberic Acid, aa^-Diaminosebacic Acid, aa^-Diaminoazelaic Acid,
are prepared from the corresponding dicarboxylic acid by bromination and
reaction with two molecules of NH,. When heated they break down into COa
and alkylene diamines (p. 333) (C. 1905, II. 462 ; 1906, II. 764). Dimethyl
Dihydroxyadipic Acids are formed from acetonyl acetone and hydrocyanic acid
(B. 29, 819). Cineolic Acid, C10H-lgO8, is the anhydride of a-hydroxyisopropyl
a-methyl a-hydroxy-adipic acid, comparable to the alkylene oxides (see Cineol,
Vol. II.).
Dihydroxy suberic Acid and Dihydroxysebacic Acid ; see Adipic Dialdehyde
and Suberic Dialdehydes (p. 348) (C. 1905, II. 462 ; 1907, II. 1236).
Dihydroxy-olefine-earboxylie Acids.
Dihydroxymaleic Acid, HO2C.C(OH):C(OH).CO2H+2H2O, may perhaps be
looked on as being oxalohydroxyacetic acid, HO2CCO.CH(OH)CO2H (A. 357,
291). It is formed when tartaric acid is oxidized with hydrogen peroxide in
presence of small quantities of ferrous salts in sunlight. A warm solution of
HBr in glacial acetic acid converts it into an isomeric body, probably dihydroxy-
fumaric acid. When heated with water it decomposes into 2CO2 and glycol
H02C.C:CHN
aldehyde ; ammonia produces Pyrazine Dicarboxylic Acid,
N:CHC.C02H
Oxidation of the sodium salt of dihydroxymaleic acid with bromine in acetic
acid gives rise to sodium dihydroxytartrate (p. 608) ; whilst oxidation with ferric
salts produces glyoxyl carboxylic acid (p. 545) (C. 1905, II. 456). Diacetyl
Dihydroxymaleic Acid, m.p. 98°. See also Dichloro- and Dibromo-maleic Acids,
and their decomposition products (p. 514) (B. 38, 258).
DIKETONE DICARBOXYLIC ACIDS 607
ii. HYDROXY-KETO-DICARBOXYLIC ACIDS.
Ethoxyoxalacetic Ester, CaH5OjC.COCH(OC2H6)CO2C2H6, b.p.n 155°, is
prepared from oxalic ester and ethyl glycollic ester. When distilled undei
ordinary pressure it gives ethoxymalonic ester (B. 31, 552). See also Dihydroxy-
maleic Acid (above).
/CH— COZC,H,
N^ |
^
Nitrilosuccinic Dimethyl Ester, N | , b.p.40 154°, is produced
^C - CO2CaHB
by the reaction of the silver salt of /J-oximidosuccinic ester (p. 567) and iodo-
ethane and subsequent distillation (B. 23, R. 561 ; 24, 2289).
Glycolyl Malonic Acid ; y-Hydroxyacetoacetic a-Carboxylic Acid, HOCH2-
COCH(COaH)2, is a hypothetical acid, from which is derived Tetronic a-Carboxylic
ester, OCH,COCH(CO,R)CO ; methyl ester, m.p. 172° with decomposition ; ethyl
ester, m.p. 125°. The substances are prepared from sodium malonic ester and
acetyl glycollic chloride or chloracetyl chloride, of which the desmotropic
aci-form, OCHaC(OH):C(CO2R)CO, are strong acids like tetronic acid itself
(p. 544) into which they pass on hydrolysis and loss of COa. Sodium cyan-
acetic ester and chloracetyl chloride produce Chloracetyl Cyanacetic Ester,
C1CH2COCH(CN)CO2R ; methyl ester, m.p. 73° ; ethyl ester, 43°. The silver
salt and iodoethane yield the O-ethyl ether of the aci-form, C1CH2C(OC2H6):-
C(CN)CO2C2H5, m.p. 94°, which with ammonia gives the a»m«0-compound,
ClCH2.C(NH2):C(CN)COaCH5, m.p. 129°. The sodium salt of chloracetyl
cyanacetic ester, however, reacting with ammonia forms a lactone — Cyanoketo-
pyrrolidone, NHCH2COCH(CN)CO, m.p. 221° with decomposition (B. 41,
2399). Homologous with the tetronic carboxylic esters is Carbotetrinic Ester,
OCH2COCH(CHaCOaC2H6)CO, m.p. 96°, which results from distillation of
bromacetos-accinic ester.
CH3C(C02H)CH8v
a-Keto-y-valerolactone y-Carboxylic Acid, /CO, m.p. 117°,
O - —CO /
results from the spontaneous decomposition of pyroracemic acid (p. 407), or
more quickly under the influence of hydrochloric acid. It reacts also in the
tautomeric enol-form, yielding a-phenylhydrazone, which, on cleavage of the
lactone ring and loss of water passes into phenyl methyl pyridazone carboxylic
CH3C=GH — C.COaH
acid, (Vol. II.). Alcoholic hydrochloric acid converts
CON(C6H6)N
the keto-valerolactone acid into y-Methyl Ketoglutaconic Ester, CH3C(CO2C2H5):-
CH.COCO2C2H5, b.p.28 183°, whilst hot strong hydrochloric acid produces
pyrotartaric acid (p. 493) (A. 317, I ; 319, 121 ; C. 1902, II. 508 ; 1904, II. 193).
C2H6C(C02H).CHCH,
a-Keto-p-methyl-y-caprolactone-y-carboxylic Acid, \ \ , m.p.
128°, is produced from a-methyl oxalacetic ester (p. 567) by 70-80 per cent.
sulphuric acid (B. 35, 1626).
12. DIKETONE DICARBOXYLIC ACIDS
C(OH)2.CO2H
Dihydroxytartarie Acid, | , m.p. 98° with decomposition, is ob-
C(OH)2.CO2H
tained (i) when protocatechuic acid, pyrocatechin, or guaiacol (Vol. II.), in
ethereal solution, is acted on with nitrous acid ; (2) by oxidation of dihydroxy-
maleic acid ; and (3) by spontaneous decomposition of nitrotartaric acid (see
A. 302,291, footnote).
It was formerly regarded as carboxytartronic acid, C(OH)(CO2H)3. Its
formation from the benzene derivatives just cited is proof for the assumption that
in benzene one carbon atom is combined with three other carbon atoms. Howevei|
6og ORGANIC CHEMISTRY
Kekule removed the basis from this assumption when he showed that the body
supposed to be carboxytartronic acid could also be made from nitrotartaric
acid by the action of an alcoholic solution of nitrous acid, and then by reduction
be converted into racemic and mesotartaric acids. He therefore named it dihy-
droxytartaric acid, for it sustains the same relation to tartaric acid that glyoxy lie
acid bears to glycollic acid, and mesoxalic acid to tartronic acid (A. 221, 230).
Glyoxal is formed when sodium dihydroxytartrate is acted on with sodium
hydrogen sulphite. The sodium salt, C4H4O8Naa-f 2H2O, is a sparingly soluble
crystalline powder, which can be employed for precipitating the acid and for
the estimation of sodium (C. 1898, I. 688). Other salts (C. 1898, II. 276 ; 1905,
The dihydroxytartaric esters are not known. Diliydroxyketosuccinic Diethyl
Ester, COaCaH§.C(OH)aCO.COaCaH8, m.p. 116°, is, however, known, consisting of
colourless crystals, produced on adding water to Diketosuccinic Diethyl Ester,
CO8CaH,.COCO.CO2CaH,, b.p. 230°, b.p.18 116°, D8o = ri896, and subsequent
distillation under diminished pressure. Hydrochloric acid acting on sodium
dihydroxytartaric acid suspended in alcohol produces the dioxosuccinic diethyl
ester. It is a thick liquid with an orange-yellow colour (B. 25, 1975) (comp.
a-diketones, p. 349). When it is boiled under a reflux condenser CO splits off,
and oxomalonic ester (p. 563) and oxalic ester result (B. 27, 1304).
Oximes. Dioximidosuccinic Acid, HOaC.C(NOH)C(NOH).CO2H, and its
esters have been obtained in different stereomeric forms (C. 1908, I. 1042, etc.).
The dioxime anhydride, Furazan Dicarboxylic Acid (i) is prepared by oxidation
of dimethyl furazan (comp. p. 355) ; the dioxime peroxide of the ester (2) from
isonitroso-acctic ester (p. 405) or isonitroso-acetoacetic ester (p. 546) and nitric
acid. It is an easily decomposable oil (B. 28, 1213).
/N=C— CO,H O— N=C— COaR
(i) 0< (2) I
\N=C— COaH 6— N=C— COaR
Hydrazones. Hydrazone Pyrazolonc Carboxylic Acid (i) and Pyrazolono-
pyrazolone (2) may be taken as being the lactazam and dilactazam (comp. p. 406)
of the mono- and dihydrazone of diketosuccinic acid (see Vol. II.).
a.CO.H /N=C.COV
(2) NH< >NH
-N.NH, XCO.C=N/
Diketosuccinic Ester Monophenylhydrazone, C6H6NH.N:C(COaC2H8).CO.-
COaCaH5, m.p. 73°, is formed from oxalacetic ester (p. 566) and diazobenzene. It is
converted into the stereomeric Hydr azone, m.p. 127°, by sodium alcoholate (€.1904,
1. 580). The osazone of diketosuccinic acid readily passes into the lactazam, Phenyl-
hydrazone Phenylpyrasolone Carboxylic Acid, CeH8N.N:C(COaH)C(NNHCeH6).CO
the basis of the dye tartrazine. Diketosuccinic Diethyl Ester Osazone [C6H6NHN:
C(CO8CjH,)]a is known in three modifications, a-, m.p. 121° ; £-, m.p. 137°
Y-, m.p. 175°. The a-form gradually passes spontaneously into the /J-substance
a change which is accelerated by iodine or sulphur dioxide. All three forms are
readily converted into pyrazolone compounds.
Oxalodiacetio Acid, Ketipic Acid, HOaCCHa.COCO.CHaCO2H, is precipitated
from the ester by concentrated hydrochloric acid, as a white insoluble powder.
Heat decomposes it into 2CO, and diacetyl. The ester, CaH5O2CCHa.COCO.CHa-
COaCaHB, m.p. 77°, is prepared, similarly to oxalacetic ester (p. 566) from a
mixture of oxalic ester and two molecules of acetic ester by the action of sodium
(B. 20, 591) ; also, from oxalic ester and chloracetic ester and zinc (B. 20, 202).
An alcoholic solution of the ester is given an intense red coloration by ferric
chloride. Chlorine and bromine produce tetrachlor- and-tetrabrom-oxalodiacetic
ester. The first, known as Tetrachlorodiketoadipic Ester, is also obtained by the
action of chlorine on dihydroxyquinone dicarboxylic ester (B. 20, 3183). The
osazone of oxalodiacetic ester can be converted into di-i-phenyl-^^-bis-pyrazolone
(Vol. II.) (B. 28, 68).
a-Oxalacetoacetic Ester, HO2CCO.CH(COCH8)CO2H, is not known, but a deri-
vative, a-Cyaniminomethylacetic Ester, NCC(NH)CH(COCHg)CO2C3H5, m.p. 122°,
DIKETONE DICARBOXYLIC ACIDS 609
has been prepared from dicyariogen and acetoacetic ester by the action of
sodium ethoxide (comp. p. 417). Acids or secondary amines convert it into
the various possible desmotropic modifications of the enol type, into two isomeric
forms, m.ps. 178° and 211°, and with absorption of water into a-acetyl fi-imino-
succinamic ester, and finally into a-acetyl fi-iminosuccinimide (A. 332, 104).
y-Oxalo-a-dimethyl-acetoacetic Ester, C2H5O2C.CO.CH2COC(CH,)2CO2C,H5,
is obtained by condensing oxalic ester and a-dimethyl acetoacetic ester. When
distilled under ordinary pressure there is a partial loss of CO. The free acid,
m.p. 180° with decomposition, into CO, and (CH3)2CHCO.CH2COCO8H. Oxalo-
dimethyl-acetoacetic Ester, C2H5O2C.CO.CH2C(C2H6)2CO2C2H5, b.p. 275-285°
with decomposition, into CO and a-dimethyl acetone dicarboxylic ester (p. 569).
These esters are in general similar to oxalacetic ester (B. 33, 3432).
Se-Oxalolavulinic Acid, yt-Diketopimelic Acid, HO2C.CO.CH3COCH2CH2CO2H,
m.p. 100-125°, is obtained from its ethyl ester, m.p. 19°, the condensation product
of oxalic ester and Isevulinic ester by warming the two esters with sulphuric
acid. When heated the acid breaks down into CO2, CO, and laevulinic acid.
Reduction produces n.-pimelic acid (B. 31, 622).
aai-Diketopimelic Acid, CH2(CH2COCO2H)2, m.p. 127°, is obtained from
methyl ene bis-oxalacetic ester by hydrolysis and loss of CO2. When treated with de-
hydrating agents there is formedPyran Dicarboxylic Acid, CH2<£**
decomposes at 250° (Vol. II.) (C. 1904, II. 602).
sym.-Diacetyl- or Diacetosuccinic Acid, C8H,0O6 ; ethyl ester is formed by
electrolysis or the action of iodine on sodium acetoacetic ester (A. 201, 144 ;
B. 28, R. 452):
CH3CO.CHNa.CO2R CH3CO.CH.CO2R
+ ii - I
CH8CO.CHNa.CO2R CH3CO.CH.CO2R
Theory demands the existence of 13 isomeric forms of this body — two optically
active, and two optically inactive keto-forms, three cis-trans isomers of the
double enol-form, and four optically active and two racemic mixed keto-cnol-
fonns. Of the seven optically inactive modifications, five are known : j3 and y-
keto-forms, m.ps. 90° and 68°; c^-, a2-, and a3-enol-forms, m.ps. liquid, 21° and
31° (A. 306, 332). When heated or acted on by acids, diacetosuccinic ester
is converted into carbopyrotritaric ester (a derivative of furfurane) ; ammonia
and the amines produce pyrrole derivatives — a reaction which serves to identify
the substance (B. 19, 46). Phenylhydrazine reacts as it does with acetoacetio
ester, forming a bis-pyrazolone derivative (A. 238, 168).
When boiled with potash solution the ester undergoes the ketonic change
into CO2 and acetonyl acetone (p. 350).
unsym.-Diacetosuccinic Ester, (CH8CO)2C(CO2C2H6)CHtCO2C2H6, b.p. 275,
is formed from sodium acetosuccinic ester and acetyl chloride (J. pr. Ch. [2] 65,
532).
CH3CO.CHC02H
aQ-Diacetoglutaric Acid, . Its diethyl ester is obtained
CH3CO.CHCH2C02H
from sodium acetoacetic ester and jS-bromolaevulinic ester (p. 423). Being a
y-diketone compound, it unites with ammonia and forms a pyrrole derivative
(B. 19, 47).
CH3CO.CH C02C2H6
ay - Diacetoglutaric Ester, >CH, , is formed from form-
CH3CO.CH CO2C2H6
i»
ehyde and acetoacetic ester in the presence of small quantities of a primary or
secondary amine (Knoevenagel, A. 288, 321 ; B. 31, 1388). It passes readily into
a. tetrahydrobenzene derivative. The /9-alkyl-ay-diacetoglutanc esters prepared
from the homologous aldehydes behave in a similar manner.
CH2CH(COCH3).C02H
aS-Diaceto-adipic Acid, \ • Ethylene bromide acting
CH1CH(COCH1).CO,H
VOL. I. 2 R
6lo ORGANIC CHEMISTRY
on two molecules of sodium acetoacetic ester, forms its diethyl ester. Phenyl-
hydrazine converts it into a bis-pyrazolone derivative (B. 19, 2045).
Diaceto-dimethyl-pimelic Acid (B. 24, R. 729)-
CH2COCH2CH2C02H
Dilavulinic Acid, [4,7-Decane dione diacid,] | . results
when alcoholic hydrochloric acid acts on 8-furfural laevulinic acid (A. 294, 167).
Iodine converts disodium diacetosuccinic ester into diacetofumanc ester,
CH,CO.CCO2R
|| , m.p. 96° (B. 30, 1991).
CH,CO.C.COaR CO C H
Methenyl Bis - acetoacetic Ester, C°c^>^-CH^C<^
ethoxymethylene acetoacetic ester (p. 546).
13. HYDROXYTRICARBOXYLIC ACIDS
Citric Acid, Hydroxytricarballylic Acid (Acidum citricum), CO2H-
CH2.C(OH)(CO2H).CH2CO2H+H2O, m.p. (anhydrous) 153°, occurs
free in lemons, in currants, in cranberries, in beets, and in other acid
fruits. It is obtained on a commercial scale from lemon juice, and by
the action of certain ferments, such as Citromycetes pfefferianus and
glaber (B. 26, R. 696 ; 27, R. 78, 448).
The acid can be prepared synthetically from jS-dichloracetone ;
this is accomplished by first acting on the latter compound with
hydrocyanic acid and hydrochloric acid, whereby dichlorohydroxyiso-
butyric acid is formed, which is then treated with potassium cyanide
producing a cyanide, which is hydrolyzed with hydrochloric acid :
CHaCl CH2C1 CH2C1 CHaCN CHaCOaH
|| I
> C(OH)CN - > C(OH)COaH - > C(OH)COaH -- > C(OH)COaH
HaCl CHaCl CH2C1 CHaCN CHaCOaH
Further, citric acid is formed from acetone dicarboxylic ester,
CO(CH2.CO2R)2 (P- 568), by the action of HNC and hydrochloric acid :
sym.-citric dimethyl ester amide and sym.-citric dimethyl di-ester
(p. 611) are obtained as intermediate substances :
CHa.COaCH, CH2.C02CH3 CH2.COaCH, CHa.COaCHt CHa.CO2H
CO + C(OH)CN -*• C(OH)CONHa -> C(OH).COaH -> C(OH)COaH
CHa.COaCH, CHaCOaCHt CHaCO2CH, CHa.COaCH, CHaCOaH
Properties. — Citric acid crystallizes in large rhombic prisms, which
dissolve in 4 parts of water of 20°, the anhydrous acid crystallizes
mostly anhydrous from its solutions (B. 36, 3599). It readily dissolves
in alcohol and with difficulty in ether. The aqueous solution is not
precipitated by milk of lime when cold, but on boiling the tertiary
calcium salt separates, which is insoluble, even in potassium hydroxide
solution (see Tartaric Acid).
When heated to 175° citric acid decomposes into aconitic acid
(p. 594). Rapidly heated to a higher temperature aconitic acid breaks
down into water and its anhydride acid, which changes to C02 and
C
HYDROXYTRICARBOXYLIC ACIDS 611
itaconic anhydride, and the latter in part to citraconic anhydride (B.
13, 1541). Another portion of the citric acid loses water and CO2,
becoming converted thereby into acetone dicarboxylic acid, which
immediately splits into 2CO2 and acetone :
CHaC02H
I
C(OH)CO2H
C
HaCO,H
CCO— v
If >0
CH3C02H CH, CH.CCX
It breaks up into acetic and oxalic acids when fused with potassium
hydroxide, and by oxidation with nitric acid. Acetone dicarboxylic
acid (p. 568) is produced when citric acid is digested with concentrated
sulphuric acid, and when oxidized with permanganate (C. 1900, I.
328).
Salts. — Being a tribasic acid it forms three series of salts, and also two different
mono- and two different di-alkali salts (B. 26, R. 687).
The calcium salt, (C6H6O7)2Ca3+4H2O, is precipitated on boiling.
Esters. — Trimethyl Ester, m.p. 79°, b.p.16 176°; dimethyl ester, citric dimethyl
acidesier, CH2(CO2CH3)C(OH)(CO2H)CH2CO2CH3, m.p. 126°, is formed by partial
esterification of the acid. It crystallizes with I molecule of water and is
difficultly soluble in cold water (B. 35, 2085). Acetocitric Trimethyl Ester, b.p.16
171°, is decomposed by distillation at ordinary pressures into acetic acid and
aconitic ester (B. 18, 1954). syia..-Acetocitric Dimethyl Acid Ester, m.p. 75°;
amide, m.p. 109° (B. 38, 3194). Acetocitric Anhydride, m.p. 121° (B. 22, 984),
decomposes on distillation at ordinary pressures into CO2, acetic acid, and
Ql^»* 2 2 • / 2
, m.p. 208°,
O
is prepared from citric acid, formaldehyde, and hydrochloric acid ; or from
formaldehyde derivatives (C. 1902, I. 299, 738 ; 1908, I. 1589).
Methoxycitric Acid, (CH3O)C(CO2H)(CH2CO2H)2, m.p. 131° ; trimethyl ester,
b.p.]2 165°, is prepared from citric trimethyl ester, iodomethane, and silver oxide
(A. 327, 228).
Citr amide, C3H4(OH)(CONHa)3, when heated with hydrochloric or sulphuric
acid, is condensed to citrazinic acid, sym.-aconitimide acid, dihydroxypyridine
carboxylic acid (p. 595) (B. 17, 2687 ; 23, 831 ; 27, R. 83). sym.-C^n'c Dimethyl
Ester Amide, NH2OC.C(OH)(CH2O2CH3)2> m.p. 107°, is prepared from the nitrile,
Acetone Dicarboxylic Ester Cyanhydrin, m.p. 53°, and reacts in concentrated
sulphuric acid with sodium nitrite to form sym.-citric dimethyl ester (p. 610).
Benzoyl Citrimide Ethyl Ester, m.p. 115", is prepared from Citric Diethyl Ester
Amide, m.p. 74°, and benzoyl chloride. It is decomposed in the cold by aqueous
sodium hydroxide into benzoic acid- and asym.-aconitimido-acid (p. 595) which is
isomeric with citrazinic acid (see above) (B. 38, 3193) •
C.H,O.C.CHa.C(OCOCtH5)CO\ HOaC.CH=C— COV
V >NH — > I NNH+HO.C.C.H..
CH, CCX CHaCCK
Isocitric Acid, CO2H.CH(OH).CH(CO2H).CH2CO2H (see Trichloromethyl
Paraconic Acid, p. 557), readily passes into a y-lactone dicarboxylic acid", ester,
ixp.14 149°, is formed by reduction of oxalosuccinic ester (A. 285, 7).
a-M ethyl Isocitric Acid, CO2H.C(CH3)(OH).CH(CO2H).CH2CO2H, is formed
jom acetosuccinic ester, hydrocyanic, and hydrochloric acids. When separated
612 ORGANIC CHEMISTRY
from its salts it immediately changes into fiy-dicarboxy-y-valerolactone, which is
also formed by oxidation of isopropyl succinic acid or pimelic acid, and from
terebic acid by the oxidizing action of nitric acid. When heated it decomposes
into HaO, CO a, and pyrocinchonic anhydride (B. 32, 3861)-
(CH8)2C CH.CO2CaH5
Y-Dimethyl Butyrolactone aft- Dicarboxylic Ester, , m.p.
O.CO.CH.CO2C2H6
46°, b.p.12 174°, is prepared from /?-methyl glycidic ester (p. 539) and sodium
malonic ester. When boiled with hydrochloric acid, it yields terebic acid (p. 558)
(C. 1906, II. 421).
aa-Dimethyl y-Hydroxytricarballylic Lactone Acid (B. 30, 1960), is formed from
oa-dimethyl tricarballylic acid (see decomposition products of pinene (Vol. II.).
Cinehonie Acid, Butenyl S-Hydroxy-ap-y-tricarboxylic Lactone, m.p. 168° (A.
234, 85; B. 25, R. 904), is produced when sodium amalgam acts on cincho-
meronic acid or £y-pyridine dicarboxylic acid. When heated to 168° it breaks
down into COa and pyrocinchonic anhydride (p. 518);
N CH=C.C02H O CHa— CH.C02H CH3.C.COV
|| I > I I > II >0
CH — CH =C.C02H CO — CH2— CH.COaH CH3 C.CCK
Cinchomeronic Acid. Cinehonie Acid. Pyrocinchonic
Anhydride.
14. KETONETRICARBOXYLIC ACIDS
Carboxethyl Oxalacetic Ester, Oxalomalonic Ester, C2H6O2C.CO.CH-
(CO2C2H6)2, b.p.10 220°, is obtained from sodium malonic ester and ethyl oxalyl
chloride (C. 1898, I. 440). Nitrogen derivatives of carboxy-oxalacetic acid
include Dicyanomalonic Ester, fi-cyano-y-imido-isosuccinic ester, NC.C(NH)CH-
(CO2C2H6)2, m.p. 93°, which is prepared from dicyanogen and malonic ester
by means of sodium methoxide (p. 488). It can be hydrolyzed to Dicyano-
malonic Mono-ester, m.p. 238°, and Imido-oxalomalonic Mono-ester, m.p. 134° with
decomposition, is reduced by sodium amalgam to a-Asparigine Carboxylic Acid,
NH2COCH(NH2)CH(CO2H)2, m.p. 120° with decomposition (A. 332, 118.
a-Cyanoxalacetic Ester, C2H5O2C.COCH(CN)COaC2H6, m.p. 96°, is formed from
oxalic mono-ester chloride and sodium cyanacetic ester. It is a strong acid
(C. 1905, I. 1312).
Acetone Tricarboxylic Ester, C2HBO2C.CHaCOCH(CO2CaH5)a, is formed from
malonic ester and sodium (p. 488). Cyanacetone Dicarboxylic Ester, C2HBO2C.-
CH2COCH(CN)CO2C2H5, m.p. 44°, is prepared from sodium acetone dicarboxylic
ester and cyanogen chloride. Double decomposition of its salts with iodo-
alkyls produces O-alkyl ethers of the unsaturated enol form (C. 1901, I. 883).
ay-Dicyanacetoacetic Ester, NC.CH2CO.CH(CN)CO2C2H6, m.p. 88°, is prepared
from chloracetyl cyanacetic ester (p. 607) and potassium cyanide (B. 41,
2403).
C2H6O,C.CO.CHCOjC2H5
Oxalosuccinic Ester, , b.p.17 155°, is obtained from
CHaC02C?H5
oxalic and succinic esters and sodium ethoxide. Heat at ordinary pressure
decomposes it into CO and ethenyl tricarboxylic ester (p. 592) (B. 27, 797).
Since it is a jS-ketonic acid its alcoholic solution becomes coloured red with ferric
chloride and forms a pyrazolone derivative with phenylhydrazine (B. 27, 797 ;
A. 285, i). The sodium salt of the ester reacts with iodo-alkyls, producing the
O-ester of the enol modification. Hydrochloric acid decomposes it into CO2 and
a-ketoglutaric acid, HO,C.CH2CH2CO.CO2H (comp. p. 568) (C. 1908, II. 768).
a-Acetotricarballylic Ester, CH,CO.CH(CO2C2H6)CH(CO2C2H6)CH2(CO2C2H6),
b.p.g 175°, is formed from chlorosuccinic ester or fumaric ester and sodium aceto-
acetic ester (B. 23, 3756 ; C. 1899, I. 180).
fi-Acetotricarballylic Ester, C2H5O2CCH2C(COCH3)(CO2C2H5)CH2CO2C2H,,
b.p.,, 190°, is prepared from sodium acetosuccinic ester and chloracetic ester ;
also it results as a subsidiary product during the formation of acetosuccinic
ester (A. 295, 94). (See also a-Acetoglutaric Acid, p. 570.)
PARAFFIN TETRACARBOXYLIC ACIDS 613
Olefine Ketotricarboxylic Acids.
a-Acetaconitic Ester, C2Cjf3^2c>CH.C(CO2C2H6):CH(CO2CaH6), is formed by
the reaction of chlorofumaric ester, chloromaleic ester or acetylene dicarboxylic
ester with sodium acetoacetic ester (C. 1900, II. 92).
15. TETRACARBOXYLIC ACIDS
A. PARAFFIN TETRACARBOXYLIC ACIDS
Formation. — (i) By the action of iodine on sodium malonic esters. (20)
From the sodium derivatives of malonic esters and alkylene dihalogenides or
halogen malonic esters. (2b) From sodium tricarboxylic esters and halogen
acetic esters. (3) By the addition of sodium malonic esters to the esters of
unsaturated dicarboxylic acids, etc. Usually they are only known in the form of
their esters.
sym. - Ethane Tetracarboxylic Acid, Dimalonic Acid, (CO2H)SCH — CH-
(COOH)2, m.p. 1 68*, heated to higher temperatures becomes ethylene
succinic acid. It is obtained from its ester by means of sodium hydroxide (B. 25,
1158). The ethyl ester, m.p. 76°, b.p. 305° with decomposition, is produced by
electrolysis (B. 28, R. 450) ; by the action of chloromalonic ester and of iodine
on sodium malonic ester ; and by heating dioxalosuccinic ester (p. 656) Potassium
hydroxide hydrolyses it to ethane tricarboxylic acid with the elimination of CO2
(p. 592). See B. 28, 1722, for the dihydrazide.
Sodium ethoxide converts ethane tetracarboxylic ester into a disodium
derivative, which yields tetrahydronaphthalene tetracarboxylic ester (B. 17,
449) with o-xylylene bromide, CeH4(CH2Br)2.
Ethyl Ethane Tetracarboxylic Ester, B. 17, 2785.
Dimethyl Ethane Tetracarboxylic Ester, B. 18, 1202 ; 28, R. 451.
Diethyl Ethane Tetracarboxylic Ester, B. 21, 2085 ; 28, R. 452.
Alkylene Dimalonic Acids. — Methylene,- ethylene-, and trimethylene-dima-
Ionic acids are, for practical reasons, included in this class. Their ethyl
esters are produced when methylene iodide, ethylene bromide, and trimethylene
bromide act on sodium malonic esters ; also, by the action of aliphatic aldehydes
on malonic ester in the presence of diethylamine, piperidine, and similar bases.
In the latter case, the corresponding aldehyde amines are formed as intermediate
compounds, such as methanol piperidine, CH2(OH)(NC6H10), or methylene bis-
piperidine, CH2(NC5H10)2, which react with malonic ester to form alkylidene
dimalonic esters.
Methylene Dimalonic Ester, Dicarboxyglutaric Ester, fi-Propane Tetracarboxylic
Ester, CHatCHfCOjjCaHJJjj, b.p.18 205°; dimethyl ester, m.p. 48°, is formed
(i) from formaldehyde or methylene iodide (B. 22, 3294; 27, 2345; 31, 738,
2585), and malonic ester; also (2) by reduction of ^3-propylene tetracarboxylic
ester (B. 23, R. 240). Ammonia produces the tetramide, CH2[CH(CONH2)2]2,
m.p. 249°, which, when heated above its melting point, passes into the diimide,
CH2[CH(CO2)NH]2 (J. pr. Ch. [2] 66, i). Sodium alcoholate and iodo-alkyls
produce methylene dialkyl malonic ester, from which aardialkyl glutaric acids can
be obtained by decomposition.
Ethylidene Dimalonic Ester, CH,.CH.[CH(CO2C2H6)2]2, is produced by the
union of ethylidene malonic ester (p. 508) and sodium malonic ester.
Ethylene Dimalonic Ester, Butane Tetracarboxylic Ester, (COaC2Hg)a-
CH — CH2.CH2 — CH^OjCjHgJa, is formed together with cyclopropane dicar-
boxylic ester when ethylene bromide acts on sodium malonic ester (B. 19,
2038).
See, further, trimethylene i.i-dicarboxylic acid and hexamethylene 1,1,4,4*
tetracarboxylic ester (Vol. II.). Its di-sodium compound reacts with di-iodo-
methane to form cyclopentane- 1,1,3, 3, -tetracarboxylic ester (Vol> n-) (B- 31»
195°)-
Alkyl Butane Tetracarboxylic Ester, B. 28, R. 300, 464.
Trimethylene Dimalonic Ester, Pentane Tetracarboxylic Acidt (CO2C2H6)a-
CH— CHj.CHg.CHj— CHlCOaCjH.),, is formed, together with cyclobutane
614 ORGANIC CHEMISTRY
dicarboxylic ester (q.v.) in the action of trimethylene bromide on two
molecules of sodium malonic ester. See also hexamethylene-i,i,3,3,-tetra-
carboxylic ester (Vol. II.).
It is noteworthy that the disodium derivatives of the alkylene dimalonic esters
are converted by the action of bromine or iodine, or of CH?I2 and CH2Br.CH2Br,
into cycloparaffin tetracarboxylic esters. The alkylene dimalonic acids split off
two CO2-groups and yield alkylene diacetic acids ; so, too, the cycloparaffin
tetracarboxylic acids, obtained from the alkylene dimalonic acids, yield cyclo-
paraffin dicarboxylic acids :
/CH(C02C2H6)2 /CCCO^Hj), /CHCOjH
CH,< - > CH2< | - > CH2< |
XCH(CO2C2H5)2 XC(CO2C2H6)2 XCHCO2H
Methylene Dimalonic Acid. Trimethylene Tetracar- Trimethylene Dicarboxylic
boxvlic Acid. Acid.
CH2CH(C02C2H6), CH2C(C02C2H6), CH2CHCO2H
CH2CH(C02C2H6)2 CH2C(C02C2H6)2 CH2CHCO2H
Ethylene Diamalonic Acid. Tetramethylene Tetracar- Tetramethylene Dicarboxylic
boxylic Acid. Acid.
,CH.CH(C02C2H6)2 /CH2C(C02C2H6)2 /CH2— CHCO,H
CH2< -^CH2< | ->CH2< |
XCH2CH(C02C2H6)2 XCH2C(C02C2H5)2 XCH2— CHCO2H
Trimethylene Diamlonic Acid. Pentamethylene Tetracar- Pentamethylene Dicarboxylic
boxylic Acid. Acid.
Propane afifiy-Tetracarboxylic Acid, Malonic Diacetic Acid, (HO2C)2C(CH,-
CO2H)2, m.p. 151° with decomposition into CO2 and tricarballylic acid (p. 593) ;
ethyl ester, b.p. 200, 295°, is prepared from sodium ethane tricarboxylic ester
and chloracetic acid.
Tetracarboxylic acids are formed by the addition of sodium malonic and sodium
alkyl malonic esters to the olefine dicarboxylic esters. These acids lose COf
and become tricarballylic acids (p. 593) (J. pr. Ch. [2] 35, 349; B. 24, 311 ;
24, 2889 ; 26, 364). If citraconic ester be added to sodium malonic ester and
sodium alkyl malonic ester, a further partial condensation takes place of the first
formed tetracarboxylic ester to Ketocyclobutane Tricarboxylic Ester (Vol. II.) (B. 33,
3742) •
CO2R CH2CO,R CO— CHCO2R
RO.C.CH - C(CH,)C02R RO2C.CH— CfCHJCO.R.
Propane aajSy - Tetracarboxylic Ester, (CO2C2H6)2CH.CH(CO2C2H6).CHa'
CO2C2H6, b.p. 203°, is obtained (i) from fumaric ester and sodium malonic
ester (comp. ethylidene dimalonic ester) ; (2) from monochlorosuccinic ester and
sodium malonic ester (B. 23, 3756; 24, 596). Tricarballylic acid is produced
when the ester is hydrolyzed with alcoholic potassium hydroxide.
a-Ethyl Propane aofiy -Tetracarboxylic Ester is formed from sodium ethyl
malonic ester and fumaric ester. It yields a sodium salt, (C2H6O2C)2C(C2H6).-
CH(CO2C2H8).CHNa(CO2C2H$), which, with iodomethane, gives a-ethyl y-
methyl propane aafiy-tetracarboxylic ester (comp. p. 593) (B. 33, 3743).
aa-Dimethyl fi-Cyanotricarballylic Ester, b.p.15 234°, is prepared from sodium
cyanosuccinic ester (p. 592) and bromisobutyric ester (C. 1899, I. 826). Boiling
dilute hydrochloric acid hydrolyzes it to oa-dimethyl tricarballylic acid (p. 594).
^ Butane ajSyS - Tetracarboxylic Acid, CH2(CO2H)CH(CO2H)CH(CO2H)CH2. -
(CO2H), m.p. 244°, is prepared from a-malonic tricarballylic acid. Its dianhydride
m.p. 173° (B. 26, 364 ; 28, 882).
Methylene Disuccinic Acid, CHt[CH(COaH)CH,(CO2H)]t, m.p. 216° with
decomposition (C. 1902, II. 733).
j.jv .,.t
Trimethylene Disuccinic Acid, >CH.[CH,],.CH< , m.p.
H02C/ XC02H
159 , is produced when hydrochloric acid effects the hydrolysis of trimethylene
dicyanosuccinic ester, the reaction product of trimethylene bromide and sodium
cyanosuccinic ester (C. 1899, I. 326).
PENTAHYDRIC ALCOHOLS, PENTITOLS 615
B. OLEFINE TETRACARBOXYLIC ACIDS
Ethylene Tetracarboxylic Ester, (C2H6O2C)2C=C(CO2C2H6)2, m.p. 58°, b.p.
325°, is formed from disodium malonic ester and iodine ; from chloromalonic
ester and sodium ethoxide (B. 29, 1290) ; and from bromomalonic ester and
K2CO, or tertiary bases (B. 32, 860 ; 34, 2077).
Dicarboxyl Glutaconic Acid, Propylene aayy-Tetracarboxylic Ester, Methenyl Bis-
malonic Ester, (C2H6O2C)2CH.CH=C(CO2C2H6)2, is formed from sodium malonic
ester and chloroform or carbon tetrachloride (B. 35, 2881). It is an oil, which
is converted by the action of piperidine in benzene solution into two dimolecular
modifications, m.ps. 103° and 88° ; these are transformed into the sodium salt
of the ordinary ester by sodium alcoholate. The ester melting at 103° is
hydrolyzed by hydrochloric acid into the bimeric glutaconic acid, m.p. 207°
(p. 521), whilst the ordinary ester, similarly treated, yields the single glutaconic
acid, m.p. 139° (B. 34, 6757). Reduction with sodium amalgam produces the
fluid dicarboxyl glutaric ester (p. 613). When heated it passes into the B-lactone,
m.p. 94°, by loss of alcohol (B. 22, 1419 ; 26, R. 9 ; A. 297, 86).
aH, C2H6OaC.C=C.OC,H§
-C2H6OH
CH -^-> CH O
I! !! |
CjHgOjC.C.COaC.H, C2H6O2C.C— CO
Aqueous alkali hydroxide decomposes it into formic acid and malonic acid,
together with glutaconic acid (p. 520) (B. 27, 3061 ; C. 1897, I. 29, 229) (comp.
also isoaconitic (p. 595). Ammonia, hydrazine, and hydroxylamine causes the
splitting off of a malonic ester from the dicarboxyl glutaconic ester molecule,
wa^reby a cyclic derivative of hydroxymethylene malonic ester is formed (p. 561).
Aniline combines with it at o° in ethereal solution to form ^-Anilino-dicarboxyl-
glutaric Ester, m.p. 46°, which, by further action of aniline, undergoes the decom-
position described above (B. 30, 1 757, 2022). When sodium dicarboxyl glutaconic
ester is heated with alcohol to 150°, trimesic acid (Vol. II.) is formed, a reaction
which probably also depends on primary formation into hydroxymethylene
malonic acid (C. 1901, II. 822).
ay-Dicyanoglutuconic Ester, C«H«°|£>CH— CH=C<£°2C'H«, m.p. 178°,
and ay-Dicyanoglutaconic Amide are formed from chloroform or carbon tetra-
chloride and sodium cyanoacetic ester or sodium cyanacetamide respectively
(C. 1898, I. 29, 37 ; B. 26, 2881).
Propylene afiyy-Tetracarboxylic Acid. A derivative of this is a-Cyanaconitic
Fster, CNCH(CO2C2H6)C(CO2C2H6):CH(CO2C2H6, b.p.S6 215°, which results
from the reaction of cyanacetic ester, oxalacetic ester, and sodium alcoholate.
The sodium salt of the ester and iodomethane give first a-cyano-a- or -y-methyl-
aconitic ester, b.p.25 211°, and then a-cyano-ay-dimethyl-aconitic ester, CNC(CH8)-
(C02C2H6).C(C02C2H5):C(CH8)C02C2H6, b.p.26 206° (C. 1906, II. 21).
Butene Tetracarboxylic Ester, CH2(CO2R)C(CO2R)2CH:CH(CO2R), b.p.14 216-
218°, is formed from sodium isaconitic ester and bromacetic ester (C. 1902, II.
722).
VII. THE PENTAHYDRIC ALCOHOLS OR PENTITOLS AND
THEIR OXIDATION PRODUCTS
I. PENTAHYDRIC ALCOHOLS, PENTITOLS
One of these, adonitol, occurs in nature ; all the rest have been
obtained by the reduction of the corresponding aldopentoses with
sodium amalgam. Their constitution follows from that of the aldo-
pentoses from which they have been prepared (p. 616). The simplest
pentitol, C5H7(OH)6 or CHa.OH.CHOH.CHOH.CHOH.CHaOH. can
6i6 ORGANIC CHEMISTRY
have five theoretical modifications, because in the formula two asym-
metric carbon atoms are present, and they are separated by a non-
asymmetric carbon atom. There are two optically active modifica-
tions, one of which is known as 1-arabitol. There is also an inactive
resolvable modification, produced by the union of the preceding forms,
and finally, there exist two optically inactive modifications due to
internal compensation. These can not be resolved, and are known as
xylitol and adonitol. The pentitols are oxidized to pentoses by
bromine and sodium hydroxide (B. 27, 2486). Comp. p. 640 for
the stereochemical constitution of the pentitols.
The number of possible classes of pentahydric alcohols is 21 ; that of the
classes of substances which can be termed oxidation products of the pentitols
is 55, if the hydroxy-compounds are not divided into sub-classes according to
the character of the alcoholic hydroxyls, otherwise the number rises to 231.
1. 1-Arabitol, C6H7(OH)5, m.p. 102°, is Isevo-rotatory after the addition of
borax to its aqueous solution. It is produced by the reduction of ordinary or
1-arabinose (p. 618), and has a sweet taste (B. 24, 538, 1839 note). Benzal
Arabitol, m.p. 150° (B. 27, 1535). Diacetone Arabitol, b.p.23 145-152° (B. 28,
2533)- d-Arabitol is dextro-rotatory, and is produced by reduction of d-arabinose
or d-lyxose. It combines with 1-arabitol to form the racemic [d+\]-Arabitol,
m.p. 106° (B. 32, 555 ', 33, 1802).
2. Xylitol, C,H7(OH)6, is syrup-like and optically inactive. It results from
the reduction of xylose (p. 619) B. 24, 538 ; 1839 note ; R. 567 ; 27, 2487).
3. Adonitol, C6H7(OH)5, m.p. 102°, is optically inactive. It occurs in Adorns
vernalis, and is produced by the reduction of ribose (p. 619) (B. 26, 633).
Adonitol Diformacetal, m.p. 145° (B. 27, 1893).
Adonitol Diacetone, b.p.17 150-155°.
4. Rhamnitol, CH3.C5H$(OH)5, m.p. 121°, is dextro-rotatory ; it results
from the reduction of rhamnose (p. 619 ; B. 23, 3103). Dimethylene Rhamnitol,
CH3.C6H6O4(CH2)2OH, m.p. 138° (A. 299, 321).
Aminotetroles : Arabinamine, CHaOH[CH(OH)]3CH2NH2, m.p. 99°, is laevo-
rotatory, and is formed from 1-arabinose oxime (p. 618) by reduction with sodium
amalgam. It is a strong base, and is reduced by hydriodic acid to n-amylamine.
Xylamine is prepared from xylose oxime, and is a colourless syrup (p. 619),
(C. 1904, I. 579).
2. TETR AH YDROXY ALDEHYDES, ALDOPENTOSES
The tetrahydroxyaldehydes, the first oxidation products of the
pentahydric alcohols, are closely related to the pentahydroxyaldehydes
or aldohexoses, the first class of the carbohydrates in the more re-
stricted sense, to which also the aldopentoses are very similar in
chemical behaviour. Whereas formerly the carbohydrates occupied a
special position in the province of aliphatic chemistry, they are now
found to be very closely allied to simpler classes of bodies. All alde-
hyde- and ketone-alcohols, which can be regarded as the first oxida-
tion products of the simplest representatives of the polyhydric alcohols,
contain, like the carbohydrates in a narrower sense, not only carbon,
but also hydrogen and oxygen in the same proportion as exist in
water, e.g. :
CHO CHO CHO CHO CHO
CH2OH CHOH [CHOH]f [CHOH], [CHOH]4
Glycolyl CH2OH CH2OH CH2OH CH2OH
Aldehyde Glycerose Erythritos Arnbinose Dextrose
(Diose, C2H4Oa) (Tnose, C3H608). (Tetrose ,C4H8O4). (Pentose, C,H10Ofi). (Hexose,C8HiaO«)'
TETRAHYDROXYALDEHYDES, ALDOPENTOSES 617
The simplest carbohydrates are, therefore, aldehyde-alcohols, such
as those just mentioned, or ketone-alcohols — e.g., fructose, CH2OH.-
CO.[CHOH]3CH2OH (p. 635).
The aldopentoses show the following reactions in common with
the aldohexoses : I. They form ethers with alcohols in the presence
of small quantities of hydrochloric acid (B. 28, 1156).
la. They combine with the mercaptans to form mercaptals in the
presence of hydrochloric acid (B. 29, 547).
za. They combine with aldehydes, especially with chloral and
bromal.
2b. They unite with acetone in the presence of small quantities
of hydrochloric acid.
3. They are reduced by sodium amalgam to alcohols : pentitols.
4. Nitric acid oxidizes them to hydroxycarboxylic acids : tetra-
hydroxymono- and trihydroxydicarboxylic acids ; they reduce Fehling's
solution.
5. They yield osamines with methyl alcoholic ammonia (B. 28, 3082).
6. Hydrazine converts the pentoses into aldazines (B. 29, 2308).
7. Phenylhydrazine changes them to hydrazones and characteristic
dihydrazones : osazones.
8. They yield oximes with hydroxylamine.
9. By successive treatment with hydrocyanic acid and hydrochloric
acid they pass into pentahydroxyacids, the lactones of which may be
reduced to hexoses (p. 630), whereby consequently the synthesis of a
hexose from a corresponding pentose is realized.
However, the aldopentoses are (i) not fermented by yeast ; (2)
they yield furfuraldehyde or alkyl furfurals when they are distilled
with hydrochloric acid or with dilute sulphuric acid. This reaction
can be applied in the quantitative determination of the aldopentoses
(B. 25, 2912). (3) When they are heated with phloroglucinol and
hydrochloric acid they give a cherry-red coloration (B. 29, 1202).
Formation. — Their production from animal and vegetable sources
will be indicated under the individual aldopentoses. However, a
reaction will be given in this connection, which promises to afford a
general method for the conversion of aldohexoses into aldopentoses.
On treating d-dextrosoxime (p. 634) with acetic anhydride and
sodium acetate, the nitrile of pentacetyl gluconic acid is obtained.
This, when treated with ammoniacal silver solution gives up hydro-
cyanic acid, and is converted into d-arabinose diacetamide, which
on hydrolysis with hydrochloric acid yields d-arabinose (B. 32, 3666).
CH=N(OH) CN
H.C.OH HCO.COCH, H.CO
HO.C.H CH3COOCH HO.C.H
H.C.OH HCO.COCH, H.C.OH
I I I
H.C.OH HCO.COCH, H.C.OH
CH.OH CH8O.COCH, CH,.OH
d-Dextrosoxime. Nitrile of Pentacetyl d-Arabinose.
Gluconic Acid.
6i8 ORGANIC CHEMISTRY
When d-dcxtrose is oxidized with chlorine water it is converted into
d-gluconic acid which is further changed by hydrogen peroxide in
presence of ferric acetate into d-arabinose (B. 32, 3672) :
CHO C02H
H.C.OH H.C.OH HCO
I ! I
HO.C.H HO.C.H HO.C.H
| > | -> |
H.C.OH H.C.OH H.C.OH
H.C.OH H.C.OH H.C.OH
CH2OH CH2OH' CH2OH
d-Dextrose. d-Gluconic Acid. d-Arabinose.
d-Arabinose is the first aldopentose to be prepared synthetically,
as it may be obtained from d-dextrose (p. 637) which can be
synthesized.
The two degradation methods described above have led to the
following reactions : the production of 1- and d-xylose from 1- and d-
gulonic acid (see below, and p. 619) ; lyxose from galactose and galac-
tonic acid (p. 619) ; 1-erythritose and 1-threose from 1-arabinose and
1-xylose (p. 597) ; d- and 1-erythritose and 1-threose from 1- and
d-arabonic acid and 1-xylonic acid, etc.
The aldopentoses of the formula CH2OH.CHOH.CHOH.CHOH.CHO, con-
taining three asymmetric carbon atoms, can appear theoretically in eight optically
active isomers, and four optically active, racemic (or [d+1] modifications which
can be resolved (p. 639).
i. Arabinose, C4H6OH)4CHO, is known in three modifications.
1- Arabinose, Pectinose, m.p. 160°, is formed when cherry gum and other gums
(p. 663) are boiled with dilute sulphuric acid (B. 35, 1457 ; 37, 1210). Reduction
produces 1-arabitol (p. 616), and oxidation 1-arabonic acid (p. 620) and 1-tri-
hydroxyglutaric acid, m.p. 127° ; hydrochloric acid gives rise to furfural. It
is dextro-rotatory, [a]D= + 105-25°, and it reduces Fehling's solution. Methyl 1-
Arabinose, C6H9O6.CHa, m.p. 170° (B. 26, 2407; £8, 1156), is prepared from
arabinose, methyl alcohol and hydrochloric acid. The action of iodomethane
and silver oxide produces methylation of the OH-groups, forming Trimethyl
Methyl-Arabinose, m.p. 44°, b.p.14 124°. Hydrochloric acid hydrolyzes this
substance to Trimethyl Arabinose, (CH3O)3C6H7O2, b.p.19 148-152° (C. 1906,
II. 1045). l-Arabinosazone, C6H8O3(N2HC6H6)2, m.p. 160° (B. 24, 1840, footnote).
Arabinosone (B. 24, 1840, footnote; C. 1904, I. 579). \-Arabinose p-Bromo-
phenylhydrazone, m.p. 150-155° (B. 27, 2490). l-Arabinose Semicarbazide,
m.p. 163° with decomposition (C. 1897, II. 894). l-Arabinose Oxime, m.p. 133°
(B. 26, 743) can be degraded to 1-erythritose (p. 597), and reduced to 1-arabinamine
(p. 616). Arabinose Ethyl Mercaptal, m.p. 125°. Arabinose Ethylene Mercaptal,
m.p. 154°. Arabinose Trimethylene Mercaptal, m.p. 150° (B. 29, 547). Arabino-
Moral, a-form, m.p. 124°; /3-form, m.p. 183°. Arabinobromal, C6H8O6.CH.CBr3,
m.p. 210° (B. 29, R. 544). Arabinose Diacetone, m.p. 42° (B. 28, 1164). Arabinose
Tetranitrate, m.p. 85° (B. 31, 71). A cetochlor arabinose, C6H6C1(OCOCH3)S, m.p.
149°, and Acetobromarabinose, C6H8Br(OCOCH3)8, m.p. 137°, are prepared from
arabinose and acetyl chloride and bromide respectively. Silver acetate converts
them into Tetracetyl Arabinose, C3H6O(OCOCH3)4> m.p. 80° (C. 1902, I. 911).
d-Arabinose is prepared (i) by degradation of d-dextrose oxime; from the
reaction product it is best separated as the diphenylhydrazone, C4H5(OH)4-
CH :N-H(C6H6)2, which is decomposed by formaldehyde (C. 1902, I. 985); (2)
by oxidation of d-gluconic acid by H2O2 (above), or by heating a solution of
mercuric d-gluconate (C. 1908, I. 1166). It is l&vorotatory, [a]D= — 105°. d-
Arabinosazone, m.p. 160°. d-Arabinose DiacetamidetC6H.10O^(NH.COCU3)2, m.p.
TETRAHYDROXYMONOCARBOXYLIC ACIDS 619
[d-j-l]-Arabinose, m.p. 164°, is produced by the union of the two optically
active forms of arabinose. It occurs in the urine of a sufferer from pentosuria.
This is of interest, since, so far, only optically active sugars have been found to
be produced as a result of metabolism. It can be resolved by asym.-.d-amyl
phenylhydrazone (B. 38, 868). [d+l]-Arabinosazone, m.p. 167° (B. 33, 2243).
2. 1-Xylose, Wood Sugar, C4H6(OH)4.CHO, m.p. 143°, is produced when
wood gums (B. 22, 1047 ; 23, R. 15 ; C. 1902, I. 301), corn-cobs (B. 24, 1657),
maize, or elder pith (B. 35, 1457) are boiled with dilute acids ; by the degrada-
tion of 1-gulonic acid (p. 649) by hydrogen peroxide (B. 33, 2142) ; also, by
pancreatic hydrolysis of nucleo-proteins (B. 35, 1467). It is dextro-rotatory, and
yields inactive xylitol (p. 616) on reduction ; oxidation converts it into 1-xylonic
acid (p. 620) and inactive trihydroxyglutaric acid, m.p. 152°. Hydrocyanic acid
produces 1-gulonic acid and 1-idonic acid (p. 650). \-Xylosazone, m.p. 160°.
d-Xylose is obtained from d-gulonic lactone by degradation. It is lavo-
rotatory (B. 33, 2145). (d+])-Xylosazone, m.p. 210-215°, with decomposition
(B. 27, 2488; 33, 2145). Methyl Xylose, CBH9O8.CH3, a-, m.p. 91°; fl-,
m.p. 156° (B. 28, 1157). Xylochloral, m.p. 132° (B. 28, R. 148).
3. Lyxose, m.p. 101°, is prepared by reduction of lyxonic lactone (p. 620) ;
from pentacetyl galactonic nitrile by loss of hydrocyanic acid (B. 30, 3103) ; and
from d-galactonic acid and H2O? (B. 33, 1798). Addition of hydrocyanic acid
and hydrolysis produces galactonic and talonic acids (B. 33, 2146).
4. Ribose, C4H6(OH)4CHO, is produced by oxidation of 1-arabinose to
1-arabonic acid, conversion of this 1-arabonic acid (p. 620) and reduction of the
lactone of this acid (B. 24, 4220).
5. Apiose, B-Hydroxymetkyl Erythritose, (CH2OH),C(OH)CH(OH)CHO, is pre-
pared by hydrolysis of apiine, a glucoside occurring in parsley (Vol. II.). It
differs from the isomeric pentoses by reason of its branched carbon chain. Oxida-
tion with bromine water produces tetrahydroxyisovaleric acid (A. 321, 71).
6. Rhamnose, or Isodulcitol, CH3(CHOH)4CHO+H2O, m.p. 93°, in
anhydrous form ; b.p. 122-126° when crystallized from acetone. It is dextro-
rotatory (B. 29, R. 117, 340). It results upon decomposing different glucosides
(quercitrine, xanthorhanmine, rhamninose, a disaccharide, derived from galac-
tose and rhamnose (C. 1900, 1, 251 ),hesperidine, naringine) with dilute sulphuric
acid. Isodulcitol yields a-methyl furfural when distilled with sulphuric acid (B.
22, R. 751).
It gives rise to rhamnitol upon reduction, and by oxidation 1-trihydroxy-
glutaric acid (m.p. 127°). HNC and hydrochloric acid convert it into rhamnose
carboxylic acid (p. 650 ; B. 22, 1702) ; oxime has been decomposed into methyl
tetrose (p. 597 ; B. 29, 1378) ; hydrazone, m.p. 159°, and its osazone, m.p. 180°
(B. 20, 2574). Acetone Rhamnose, C,H10O6 : C3H6, m.p. 90° (B. 28, 1162).
Rhamnose Ethyl Mercaptal, m.p. 136°. Ethylene Mercaptal, m.p. 169° (B. 29,
547). Tetranitrate, m.p. 135° (B. 31, 71).
7. Isorhamnose has been obtained by the reduction of the lactone of isorham-
nonic acid.
8. Chiaovose, CH3[CHOH]4CHO, isomeric with rhamnose, is a product
obtained by decomposing chinovine, occurring in varieties of quina and cinchona
with hydrochloric acid. Osazone, m.p. 193-194° (B. 26, 2417).
9- Rhodeose, CH3[CH(OH)]4CHO, is one of the methyl pentoses obtained
by decomposing the pentosides convovulin and jalapin (Vol. II.). It is strongly
dextro-rotatory, and is the optical antipodes to Fucose. This substance is
obtained by hydrolysis of the Fucus variety of sea-weeds with dilute sulphuric
acid. Osazone, m.p. 177°. Determination of configuration (B. 40, 2434).
3. TETRAHYDROXYMONOCARBOXYLIC ACIDS
Acids of this class are obtained by oxidizing the aldopentoses with bromine
water or dilute nitric acid. They readily pass into lactones, some of which
yield pentoses on reduction. Furthermore, oxidation changes them in part to
dicarboxylic acids. Hydriodic acid reduces some of them to lactones of the
monohydroxyparaffin carboxylic acids. All the known acids are optically
active.
Tetrahydroxy-n-valeric acids, have theoretically eight optically active forms,
as have the aldopentoses with an equal number of carbon atoms, five of which
are known, and four are [d-f-1] modifications.
620 ORGANIC CHEMISTRY
(1) l-Arabonic Acid, CO2H[CHOH]3CH2OH, [^=-73-9°, is prepared from
1-arabinose (B. 21, 3007). It readily yields a lactone, C6H8O5, m.p. 95-98°,
and is converted by oxidation into \-trihy droxyglutaric acid; phenylhydrazide,
m.p. 215° (B. 23, 2627; 24, 4219). Tetracetyl l-Arabonic Nitrile, m.p. 117°,
is produced from 1-arabinose oxime, acetic anhydride, and sodium acetate.
Silver oxide changes it into triacetyl 1-eythrose (B. 32, 3666). d-Arabonic
Acid, [a]^=+737°, is formed from d-arabinose and bromine water; lactone,
m.p. 98°. Oxidation by H2O2 converts it into d-erythritose, [d+l]-Arabonic
Lactone, m.p. 116° (B. 32, 556). When heated to 145° with aqueous pyridine it
gives 1-arabonic and pyromucic acid, together with some
(2) 1-Ribonic Acid, which, under the same conditions, is partially recon-
verted into arabonic acid. Ribonic Lactone, C3H8O6, m.p. 72-76° (B. 24, 4217) ;
phenylhydrazide, m.p. 163°.
(3) 1-Xylonic Acid is prepared from 1-xylose and bromine. It yields a
sparingly soluble bromocadmium double salt (comp. B. 35, 1473). Pyridine
converts it into
(4) d-Lyxpnie Acid; lactone, m.p. 113° (B. 30, 3107) (see also Lyxose, p. 619);
phenylhydrazide, m.p. 162°.
(5) Apionic Acid, Tetrahydroxyisovaleric Acid, (CH2OH)2C(OH)CH(OH)-
COOH, is produced from apiose (p. 619) and bromine water. Phenylhydrazide,
m.p. 127°, is converted by hydriodic acid and phosphorus into isovaleric acid
(A. 321, 78).
(6) Rhamnonic Acid is formed from rhamnose and bromine, and passes
directly into the lactone, CttH10O6, m.p. 150° (B. 23, 2992 ; A. 271, 73). Methyl
Rhamnonic Lactone, C6H8(CHt)O5, m.p. 179° (A. 309, 323). When heated with
pyridine to 150° it yields some
(7) Isorhamnonic Acid, of which the lactone, m.p. 151°, when oxidized
yields xylotrihydroxyglutaric acid (p. 621) (B. 29, 1961) (see also Isorhamnose,
p. 619).
(8) Saccharic Acids is the name given to a number of tetrahydroxypentane
carboxylic acids which are obtained from the hexoses or disaccharides by the
action of alkalis, or, better, lime-water, accompanied by atomic migration. They
readily pass into lactones, known as saccharines, which must not be confused with
saccharine (Vol. II.) a sweetening agent entirely unconnected with sugars and
their associated compounds.
CO O
Saccharine, , m.p. 1 60°, possesses a bitter taste.
CH3 C(OH).CH(OH)CH.CH2OH
CO O
Isosaccharine, , m.p. 95°.
HO.CH2.C(OH).CH2.CH.CH2OH
CO O
Metasaccharine, , m.p. 141°.
HOCH.CH2.CH.CH(OH)CH2OH
CO O
Parasaccharine, I , a syrup.
HOCHa.CH(OH).C(OH)CH2CH2
Saccharine is produced by the action of lime-water on dextrose, laevulose
and invert sugar ; iso-, meta-, and para-saccharine from lactose or galactose
and lime-water. When reduced with hydriodic acid, saccharine and isosaccharine
yield ay-dimethyl butyrolactone, whilst metasaccharine gives y-n.-caprolactone.
Nitric acid converts saccharine into a-methyl trihydroxyglutaric acid (saccharonic
acid] ; isosaccharine into ay-dihydroxyglutaric y-carboxylic acid, (HO2C)2C(OH)-
CH2CH(OH)COSH ; metasaccharine into ajSS-trihydroxyadipic acid (see below) ;
and parasaccharine to parasaccharonic acid and hydroxycitric acid (p. 622),
H2O2 (p. 618) brings about the degradation of iso- and para-saccharine to two
ketopentane trioles, HOCH2.COCH2CH(OH)CH2OH, and HOCHa.CH(OH).CO.-
CH2CH2OH, respectively ; metasaccharine gives an aldotriose metasaccharo-
pentose, HOC.CH2CH(OH)CH(OH)CHaOH, the aldehyde of a j8yS-trihydroxy-
valenc acid, which is reduced by hydriodic acid to y-valerolactone (A. 218,
37^ ; 299, 323 ; B. 18, 631, 2514 ; 35, 2361 ; 37, 3612 ; 38, 2671 ; 41, 158).
DIHYDROXYTRICARBOXYLIC ACIDS 621
4. TRIHYDROXYDICARBOXYLIC ACIDS
Trihydroxy-n.-glutaric Acids, CO?H[CHOH]3CO2H, can theoreti-
cally exist in four stereochemical modifications, corresponding with the
four pentitols (p. 615), and in addition in an inactive form, which can
be resolved.
d-Trihydroxyglutaric Acid, m.p. 127°, is prepared from d-arabinose and
nitric acid. \-Trihydroxyglutaric Acid, m.p. 127°, is formed from 1-arabinose
and nitric acid, as well as by the oxidation of rhamnose (p. 619) and sorbinose
(p. 636) (B. 21, 3276). [d+l]-Trikydroxygluiaric Acid, m.p. 154°, results from
the union of d- and 1-trihydroxyglutaric acid in acetone solution (B. 32, 558).
i-Xylotrihydroxyglutaric Acid, m.p. 152°, is formed when xylose is oxidized ; it
corresponds with xylitol (p. 616). It is very similar to, but not identical with,
the racemic acid (B. 32, 559). i-Ribotrih'ydroxyglutaric acid results from the
oxidation of ribose, and corresponds with adonitol (p. 616). It readily passes
into a lactonic acid, CSH6O6, m.p. 170° (B. 24, 4222).
Saccharonic Acid, a-Methyl Trihydroxyglutaric Acid, CH8C(OH)(CO2H)CH-
(OH)CH(OH)(CO2H), is formed by the oxidation of saccharine (see above)
with nitric acid. It changes in a desiccator, or when heated, into a laevo-rotatory
CO - O
lactone, Saccharone, , m.p. 145-156° (A. 218, 363).
CH3C(OH).CH(OH).CHC02H
Hydriodic acid converts the lactone into a-methyl glutaric acid (p. 502).
Trihydroxyadipic Acid, CO2HCH(OH)CH2CH(OH)CH(OH)CO2H, m.p. 146°
with decomposition, results from the oxidation of metasaccharine (see above)
with dilute HNO3 (B. 18, 1555 ; 37, 2668). Heated with HI it is reduced to
adipic acid.
5. DIHYDROXYKETONE DICARBOXYLIC ACIDS : The pyrone dicarboxylic
esters, resulting from the condensation of acetone dicarboxylic esters with alde-
hydes, are anhydrides (like ethylene oxide) of the dih)'droxyketone dicarboxylic
acids.
Dimethyl Tetrahydropyrone Dicarboxylic Ester,
102°, is formed from acetone dicarboxylic ester, acetalclehyde, and hydrochloric
acid (B. 29, 994)-
6. TRIKETONE DICARBOXYLIC ACIDS. Acetone Dioxalic Ester, Diethyl
Xanthochelidonic Ester, CO[CH2CO.CO?C2H5]2> m.p. 104°, is obtained from
acetone, oxalic ester, and sodium ethoxide. Hydrochloric acid converts it into
Chelidonic Ester, CO<=>O22> m.p. 63°. Some other acids, allied
with this, are also derived from pyrone, CO<>O (Vol. II.), such as
a product of dehydration of carbonyl diacetoacetic ester, CO[CH(COCH8)CO2C2H6],,
prepared from copper acetoacetic ester and phosgene (B. 19, 19).
7. DIHYDROXYTRICARBOXYLIC ACIDS
Desoxalic Acid, CO2H.CHOH.C(OH)(CO2H)2, is a deliquescent crystalline
mass ; triethyl ester, CO2C2H6.CHOH.C(OH).(CO2C2H6)2, m.p. 78°, b.p.2 156°,
results from the action of sodium amalgam on diethyl oxalate (A. 297, 96).
When its aqueous solution is evaporated, or when its ester is heated with water
or dilute acids to 100°, the acid yields carbon dioxide and racemic acid
(p. 601):
HOaC.CH(OH)C(OH)C02H)a - > HO2C.CH(OH)CH(OH)COaH+COt.
Desoxalic Acid. Racemic Acid.
Acid
radicals can be substituted for the two hydroxyl groups of the desoxalic
ester. Heated with hydriodic acid, desoxalic acid gives off carbon dioxide,
and is reduced to succinic acid.
ORGANIC CHEMISTRY
Desoxalic ester and phenylhydrazine yield phenylhydrazine glyoxylic ester,
whilst isonitrosomalonic ester and glycollic acid are the products of reaction
with hydxroylamine (B. 29, R. 9°8.
Hydroxycitrie Acid, a^-Hydroxy-tricarballylic Acid, CO2HCH?qOH)(CO,H)-
CH(OH)CO2H, m.p. 160°, accompanies aconitic, tricarballylic, and citric
acids in beet juice, and is produced by boiling chlorocitric acid (from aconitic
acid and HC1O) with alkalis or water (B. 16, 1078). It can be obtained pure by
oxidation of parasaccharine (p. 620) with nitric acid (B. 37, 3614).
ay-Dihydroxypropane aay - Tricarboxylic Acid, ay - Dihydroxyglutaric y-Car-
boxylic Acid, (CO2H)2C(OH)CH2CH(OH)COOH, results from the oxidation of
isosaccharine with nitric acid. It is a thick crystalline mass. At 100° it loses
carbon dioxide, and forms ay-dihydroxyglutaric acid. Hydriodic acid and
phosphorus convert it into glutaric acid, C,H6(COaH)a (B. 38, 2671).
8. PENTACARBOXYLIC ACIDS
Paraffin Pentaearboxylic Acids. Propane apfiyy-Pentacarboxylic Acid, py-Di~
carboxy tricarballylic Acid, (CO2H)2CH.C(CO2HJ2.CH2CO2H, m.p. 150°, is obtained
from its penta-ethyl ester, the reaction product of sodium malonic ester and
chlorethane tricarboxylic ester (p. 592). Propane aa^yy- Pentacarboxylic Methyl
Ester, ay-Dicarboxytricarballylic Ester, CH8O2C.CH[CH(CO2CH3)2]2, m.p. 86°, is
prepared from dichloracetic ester and two molecules of sodium malonic ester;
also, by reduction of dicarboxyaconitic ester (see below) with zinc and glacial
acetic acid (A. 347, 5). Similarly, reduction of dicarboxy-methyl-aconitic ester
gives rise to Butane aafiyy-Pentacarboxylic Methyl Ester, ay-Dicarboxy-a-methyl-
tricarballylic Ester, (CH3O2C)2.CH.CH(CO2CH3).C(CH3)(.CO2CH3)2, m.p. 59°.
These esters yield tricarballylic or the stereoisomeric a-methyl tricarballylic
acids on hydrolysis and expulsion of CO2.
Butane a$3y8 - Pentaearboxylic Ester, C2H5O2C.CH2CH(CO2CaH5)C(CO1-
C2H6)2.CH2CO2C2H5, b.p.162i7°, is formed from chlorosuccinic ester and sodium
ethenyl tricarboxylic ester.
Olefine Pentacarboxylic Acids : Dicarboxyaconitic Pentamethyl Ester,
(CH3O2C)2.C: C(CO2CH3).CH(CO2CH3)2, m.p. 62°, is formed by condensation
of dichloroxalic methyl ester and two molecules of sodium malonic methyl ester,
instead of the expected dicarboxy-methyl-citric ester, which loses methyl alcohol :
3 2NaCl+CH3OH.
The ester, when hydrolyzed, loses CO2 and yields aconitic acid ; with sodium
and iodomethane it forms a-Methyl Dicarboxyaconitic Ester, Butylene aa,8yy-
Pentacarboxylic Ester. CHsC(COaCH3)aC(CO8CH3) : C(CO8CH3)2, m.p. 86° A.
347, i).
Butylene apyy 8- Pentacarboxylic Ester, C2H6O2C.CH2.C(CO2C2H6)2C(CO2C2-
H6) : CHCO2C2H6, b.p.10 230°, is prepared from sodium ethenyl tricarboxylic
ester and chlorofumaric ester (B. 31, 47). Butylene aayyS- Pentacarboxylic
Ester, C2H5O2C.CH2C(CO2C2H6)2CH : C(CO2C2H6)2, b.p.12 224°, is formed from
sodium dicarboxyglutaconic ester (p. 615) and chloracetic ester (J. pr. Ch.
[2] 66, i, 104).
VIII. HEXA- AND POLY-HYDBIC ALCOHOLS, AND THEIE
OXIDATION PRODUCTS
I A. HEXAHYDRIC ALCOHOLS, HEXAHYDROXYPARAFFINS,
HEXITOLS
The hexahydric alcohols approach the first class of sugars (p. 625) —
the dextroses — very closely. They resemble them in properties ; they
have a very sweet taste, but they do not reduce an alkaline copper
HEXA- AND POLY-HYDRIC ALCOHOLS 623
solution, and are not fermented by yeast. 8-Mannitol, S-sorbitol,
and dulcitol occur in nature. These three and certain hexitols have
been prepared by the reduction of the corresponding dextroses — aldo-
and keto-hexoses — with sodium amalgam. Moderate oxidation con-
verts them into dextroses. The compounds which the hexitols yield
with aldehydes, especially formaldehyde and benzaldehyde, in the
presence of hydrochloric acid or sulphuric acid, or with acetone and
hydrochloric acid, are characteristic of them (A. 299, 316 ; B. 27, 1531 ;
28, 2531).
Theory requires the existence of 28 classes of hexahydroxy-
paraffin alcohols, which give rise to 79 classes of oxidation products,
if the hydroxy compounds are included with those of the glycol oxida-
tion products. The total number of sub-classes of oxidation compounds
amounts to 434, of which 28 are free from alcoholic hydroxyls.
The simplest hexitols with six carbon atoms contain four asym-
metric carbon atoms in the molecule. According to the theory of van
't Hoff and Le Bel, 10 simple spacial isomeric forms are possible for
such a compound.
i. Mannitol or Mannite, CH2OH[CHOH]4CH2OH, exists in three
modifications : dextro-, laevo-, and inactive mannitol ; the latter
is identical with the a-acritol made from synthetic a-acrose or [d+1]
fructose. It is the parent substance for the synthesis of numerous
derivatives of the mannitol series (B. 23, 373), and also of dextrose
(p. 632) and of Icevulose (p. 635), as will be more fully explained under
these bodies.
Ordinary, or d-Mannitol, m.p. 166°, occurs frequently in plants
and in the manna-ash (Fraxinus ornus), the dried sap of which is
manna. It is obtained from the latter by extraction with alcohol
and allowing the solution to crystallize. It is produced in the ropy
fermentation of the different varieties of sugar, and may be artificially
prepared, together with sorbitol, by the action of sodium amalgam
on d-mannose (p. 631), d-fructose (B. 17, 127 ; 23, 3684).
Mannitol crystallizes from alcohol in delicate needles, and from
water in large rhombic prisms. It possesses a very sweet taste. Its
solution is dextro-rotatory in the presence of borax. When oxidized
with care, it yields fructose (previously known as mannitose) (B. 20,
831), and d-mannose (B. 21, 1805). Nitric acid oxidizes mannitol to
d-mannosaccharic acid (B. 24, R. 763) (p. 653), erythritic acid, and
oxalic acid. Hydriodic acid converts it into 2- and 3-hexyl iodide
(B. 40, 140).
When mannitol is heated to 200° it loses water and forms the anhydrides.
Mannitan, C6H12O6, and Mannide, C6H10O4, m.p. 87°, b.p.80 176°. The latter
is also obtained by distilling mannitol in a vacuum.
Esters. — Mannitol Dichlorhydrin, C,H8C12(OH)4, m.p. 174°, is formed when
d-mannitol is heated with concentrated hydrochloric acid. Hydrobromic acid
yields the dibromhydrin, m.p. 178°.
Nitromannitol, C,H8(O.NO2)6, m.p. 113°, is obtained by dissolving mannitol
in a mixture of concentrated nitric and sulphuric acids. It crystallizes from
alcohol and ether in bright needles ; it melts when carefully heated and deflagrates
strongly. When struck it explodes very violently. Alkalis and ammonium
sulphide regenerate mannitol. Ammonia, or, better, pyridine, acting on
hexanitromannitol, produces pentanitromannitol, m.p. 82° (C. 1901, JJ. 983 ;
B. 36, 794).
624 ORGANIC CHEMISTRY
Hexacetyl d-Mannitol, C8H6(OCOCH3)«, m.p. 119° (B. 12, 2059), when
left in contact with liquid HC1, changes into Tetra-acetyl Mannitol Dichlorhydrin,
C.H.fC.H.O.^Cl., m.p. 214° (B. 35, 842).
Hexabenzoyl Mannitol, m.p. 149°-
Mannitol Triformal, CflH8O8(CH2)3, m.p. 227° (A. 289, 20).
Mannitol Tribenzal, C6H8O«(CHC8Hf)8. m.p. 213-217° (B. 28, 1979).
Mannitol Triacetone, C6H8O8(CSH8)3, m.p. 69°, is obtained from mannitol,
acetone, and a little hydrochloric acid. It has a bitter taste (B. 28, 1168).
Lsevo-mannitol, m.p. 163-164°, is obtained by the reduction of 1-mannose (from
1-arabinose carboxylic acid, p. 649) in weak alkaline solution with sodium
amalgam (B. 23, 375). It is quite similar to ordinary mannitol, but melts a
little lower, and in the presence of borax is laevorotatory.
Inactive Mannitol, [d-fl] Mannitol, m.p. 168°, is produced in a similar
manner, from inactive mannose (from [d+l]-mannonic acid). It is identical
with the synthetically prepared a-acritol (from a-acrose, p. 636) (B. 23, 383). It
resembles ordinary mannitol, bat in aqueous solution is inactive even in the presence
of borax. Nitric acid oxidizes it to inactive mannose and inactive mannonic
acid. The latter can be resolved into d- and 1-mannonic acids (B. 23, 392).
d- and 1-Mannonolactones may be reduced to d- and 1-mannoses, and these to
d- and 1-mannitols. All of these compounds have been synthesized in this way.
2. d- and 1-Iditols are colourless syrups formed by the reduction of d- and
1-iodoses ; tribenzal compounds, m.p. 219-223° (B. 28, 1979).
3. d-Sorbltol (p. 642), CH2OH(CHOH)4CH2OH, m.p. 75° (anhydrous, 104-
109°), occurs in mountain-ash berries, forming small crystals which dissolve
readily in water. It is produced in the reduction of d-dextrose, and together
with d-mannitol in the reduction of d-fructose (p. 637) (B. 23, 2623). It is
reduced to secondary hexyl iodide (B. 22, 1048) when heated with hydriodic acid.
Sorbitol Triformal, C8H8O8(CH2)3, m.p. 206° (A. 289, 23).
Triacetone Sorbitol, C8H8O8(C3H6)3, m.p. 45°, b.p.25 172°.
1-Sorbitol (p. 642), m.p. 75°, is obtained by the reduction of 1-gulose (p. 634)
(B. 24,2144).
4. Dulcitol, Melampyrin, CH2OH(CHOH)4CH2OH (p. 642), m.p. 188°,
occurs in various plants, and is obtained from dulcitol manna (originating in
Madagascar). It is produced artificially by the action of sodium amalgam
on lactose and d-galactose. It crystallizes in large monoclinic prisms, having
a sweet taste. It dissolves in water with more difficulty than mannitol, and is
almost insoluble even in boiling water. Its solution remains optically inactive even
in the presence of borax (B. 25, 2564). Hydriodic acid converts it into the same
hexyl iodide that mannitol yields. Nitric acid oxidizes dulcitol to mucic acid.
There is also an intermediate aldehyde compound that combines with two mole-
cules of phenylhydrazine and forms the osazone, C8H10O4(N,H,C6H6)2 (B. 20,
1091).
Hexacetyl Dulcitol, m.p. 171°.
Dimethylene Dulcitol, C8H10O6(CH2)2, m.p. 244° (A. 299, 318). Dibenzal
Dulcitol, C8H10O6(CHCflHB)2, m.p. 215-220* (B. 27, 1554). Diacetone Dulcitol,
c«Hio°«(C8He)a. m.p. 98°, b.p.18 194° (B. 28, 2533). Dulcitol Hexanitrate,
m.p. about 95°. Dulcitol Pentanitrate, m.p. about 75° (B. 36, 799).
5. d-Talitol, m.p. 86°, is produced in the reduction of a-talose.
Tribenzal d-Talitol, m.p. 206° (B. 27, 1527 ; C. 1908, I. 1529).
[d+1] Talitol, m.p. 66°, is formed by the reduction of the body produced
when dulcitol is oxidized with PbOE and hydrochloric acid (B. 27, 1530).
6. Rhamnohexitol, CH3.[CHOH]6.CH2OH, m.p. 173°, is formed when
rhamnohexose (p. 635) is reduced with sodium amalgam (B. 23, 3106).
7. Glucamines. These bodies stand in the same relation to the hexoseimines
and amines (p. 636) as the hexitols to the hexoses. They are formed (i) from
the hexose oximes, and (2) the hexose amines by reduction with sodium amalgam.
d-Glucamine, CH8OH.[CHOH] 4CHNH2, m.p. 128°, is prepared from dextrose oxime
and also from isodextrosamine (p. 636). It is a strong base, and is dextro-rotatory.
Together with the above are formed d-Manno-amine, m.p. 139°, d-Galactaminc,
m.p. 139°, is laevorotatory (C. 1902, II. 1356 ; 1903, II. 1237 ; 1904, I. 871).
i B. HEPTAHYDRIC ALCOHOLS : Perseitol or Mannoheptitol, C7H,(OH)7,
is known in three modifications: d-mannoheptitol, m.p. 187°, 1-mannoheptitol,
POLYHYDROXYALDEHYDES AND KETONES 625
m.p. 187°, and [d+1] mannoheptitol,m.p: 203°. The d-mannoheptitol or perseitol
occurs in Laurus persea, and is obtained, like the other two modifications,
by the reduction of the corresponding mannoheptoses (B. 23, 936, 2231). The
[d + 1] mannoheptitol is formed when equal quantities of d- and 1-manno-
heptitol are mixed (A. 272, 189). Hydriodic acid reduces it to hexahydro-
toluene (B. 25, R. 503).
a-Glucoheptitol, CH2OH(CHOH)6CH2OH, m.p. 128°, is obtain ed froma-glu-
coheptose (p. 637; A. 270, 81). Triacetone a-Glucoheptitol, C2H10O7(CaH.)a,
b.p.2420o°(B.28,2534).
a-Galaheptitol, C7H16O2, m.p. 183°, is obtained from a-galaheptose (p. 637).
Volemitol, C7H9(OH)7, m.p. 156°, dextrorotatory, is found in the pileated
mushroom, Lactarius volemus (B. 28, 1973) and in the Primulacece (C. 1902,
II. 1513)-
Anhydro-enneaheptitol, C9HltO8, m.p. 156°, is formed from acetone and
formaldehyde with lime and water. It is an anhydride of the heptahydric
alcohol [CH,OH]3 : C.CH(OH)C j [CH,OH], (B. 27, 1089 ; A. 289, 46).
i C. OCTAHYDRIC ALCOHOLS : a-Glueo-octitol, CH2OH[CHOH]8.CH2.OH,
m.p. 141°, is obtained from a-gluco-octose (p. 637, A. 270, 98). d-Manno-
octitol, CH2OH[CHOH]6CH2OH, is produced from manno-octose, m.p. 258°.
It dissolves with difficulty in water.
i D. NONOHYDRIC ALCOHOLS: Glucononitol, C8H20O,, m.p. 194°, is
obtained from glurononose (A. 270, 107).
2 AND 3. PENTA-, HEXA-, HEPTA-, AND OCTO-IIYDROXY-
ALDEHYDES AND KETONES
The long-known representatives of the first class of carbo-
hydrates, which are produced by hydrolysis from the more complex
carbohydrates, the saccharobioses (p. 657), like sucrose, maltose,
and lactose, and from the polysaccharides, — e.g. starch, dextrin,
cellulose, and others, — are pentahydroxyaldehydes and pentahydroxy-
ketones. The most important sugar of the first class is dextrose, formed
together with laevulose by the hydrolysis of sucrose. It also occurs
as the final product of the hydrolysis of starch and of dextrin. In
this connection it may be mentioned that dextrose and laevulose have
already been referred to with ethyl alcohol, and in connection with
its formation by alcoholic fermentation (p. 112).
The aldehyde character of these bodies is inferred from the ready oxidation
of certain dextroses to monocarboxylic acids, and their reduction to hexahydric
alcohols. Zincke (1880) was the first (B. 13, 641 Anm.) to suspect that ketone
ilcohols were represented among the dextroses. Kiliani, in 1885, investigating
the HNC additive products, proved that dextrose must be regarded as an aldehyde
ilcohol, and laevulose as a ketone alcohol. Hence, it is customary to distinguish
ildoses and ketoses. The same chemist also showed that arabinose was an aldo-
oentose, and in so doing laid the basis of an extension of the idea of carbohydrates.
What was lacking was a method of synthesis. It is true, sugar-like bodies had
:>een obtained from formaldehyde (p. 636), but it was E. Fischer who first demon-
strated that a well-defined sugar, a-acrose, could be isolated from it. This,
is will be observed later, became in his hands the starting-point for the synthesis
)f dextrose and of laevulose.
By reducing the lactones of the polyhydroxycarboxylic acids to hydroxy-
ddehydes or aldoses, E. Fischer developed a method for the preparation of
lydroxyaldehydes rich in carbon, or carbohydrates, from polyhydroxycarboxylic
tcids obtained synthetically from aldoses by the addition of hydrocyanic acid
ind subsequent hydrolysis. In this way carbohydrates, containing seven,
ight, and nine carbon atoms in the molecule, were gradually built up (p. 616).
The dextroses mostly crystallize badly, and for their isolation and recognition
>henylhydrazine was used. This, E. Fischer also discovered, gave the very best
VOL. I. 2 S
626 ORGANIC CHEMISTRY
assistance. Wohl showed how the oximes of the aldoses could be utilized in
their breaking down (p. 617).
The monose character of a compound is very much affected by its
constitution, as aldehyde alcohol— CH(OH).CHO, or ketone alcohol—
CO.CH2.OH, in which the aldehyde and ketone group is directly com-
bined with an alcohol group or groups. We thus have monoses con-
taining not only six, but even a less or greater number of carbon and
oxygen atoms. They are named according to the number of the
oxygen atoms.
The simplest aldose, glycolyl aldehyde, CH2OH.CHO, is an
aldodiose. Glyceric aldehyde, CH2OH.CHOH.CHO, and dihydroxy-
acetone, CH2OH.CO.CH2OH, represent an aldotriose and a ketotriose
(p. 534). The aldehyde and ketone of erythritol is an aldo- and keto-
tetrose.a-s just developed under the pentoses (p. 615). Following the
latter are the hexoses. In this class belong the real sugars : dextrose,
Icevulose, and galactose.
In addition to the long-known hexoses — dextrose, laevulose, and
galactose — many others have been discovered through E. Fischer's
investigations, so that now the hexoses must be removed from the
carbohydrate class, and be considered in immediate connection with
their corresponding hexahydric alcohols. Then follow the heptoses,
octoses, and nonoses, as well as the oxidation products of these alde-
hyde and ketone alcohols : the polyhydroxymonocarboxylic acids, the
polyhydroxyaldehydrocarboxylic acids, and the polyhydroxypolycar-
boxylic acids. After the consideration of all these, the higher carbo-
hydrates, the saccharobioses, and the poly sacchar ides, which are the
anhydrides of the hexoses, will be brought together and fully discussed
(p. 656).
2 A. PENTAHYDROXY ALDEHYDES AND 3 A. PENTAHYDKOXY-
KETONES: HEXOSES, DEXTROSES (GLUCOSES), MONOSES
Occurrence. — Some hexoses occur widely distributed in the free
state in the vegetable kingdom, especially in ripe fruits. Esters of the
glucoses (from yXuxvs, sweet) with organic acids are also frequently
found in plants. They are called glucosides — e.g. salicin, amygdalin,
coniferin, the tannins, which are dextrose esters of the tannic acids,
etc. The glucosides are split into their components by ferments,
acids, or alkalis.
Formations. — (i) They are formed by the hydrolytic decomposi-
tion of all di- and poly-saccharides, as well as of glucosides, by fer-
ments (p. 113) (B. 28, 1429), or by boiling them with dilute acids.
(2) d-Mannose and d-fructose have been made artificially by oxidizing
d-mannitol. (3) A far more important method pursued in the fo"Tiation
of the dextroses is to reduce the monocarboxylic lactones with sodium
amalgam in acid solution (E. Fischer, B. 23, 930). (4) Different
optically inactive hexoses, particularly a-acrose or [d+1] fructose
(P- 637), have been directly synthesized by the condensation of formic
aldehyde, CH2O, and glyceric aldehyde.
The [d+1] fructose, prepared in this way by E. Fischer is the parent
HEXOSES 627
substance for the complete synthesis of those forms of mannitol, dex-
trose, and laevulose, as occur in nature.
Properties. — The hexoses are mostly crystalline substances, very
soluble in water, but dissolving with difficulty in alcohol. They
possess a sweet taste. The representatives of the hexoses occurring
in nature rotate the plane of polarization, when in solution, either to
the left or to the right. The stereoisomers of the more important
tiexoses found in nature have been prepared artificially, and by the
union of the corresponding dextro- and laevo-forms the optically
inactive [d-f-1] varieties have been obtained. One of these, [d+1]
[ructose or a-acrose, as previously mentioned, has been directly syn-
thesized.
Reactions. — The hexoses show the general reactions of the alcohols,
the aldehydes, and the ketones.
(1) The alcoholic hydrogen of the dextroses can also be replaced
:>y metals on treating them with CaO, BaO, and PbO, forming saccha-
rates, which correspond with the alcoholates, and which are decomposed
y carbon dioxide.
(2) On treating the alcoholic solutions of the hexoses with a little
aseous hydrochloric acid, their ethers result : glucosides of the
alcohols (B. 26, 2400 ; 29, 2927).
(3) The hexoses combine with aldehydes, particularly with chloral,
and with ketones, in the presence of inorganic acids, with an accom-
panying loss of water (B. 28, 2496).
(4) The hydrogen of the hydroxyls can be readily replaced by acid
radicals. A mixture of nitric and sulphuric acids (p. 323) converts
:hem into esters of nitric acid (B. 31, 73) — the nitro-compounds (p. 529).
The acetyl esters are best obtained by heating the sugars with acetic
anhydride and sodium acetate or ZnCl2, whereby five acetyl groups
are thus introduced (B. 22, 2207). The pentabenzoyl esters are
prepared with even less difficulty, it being only necessary to shake
he hexoses with benzoyl chloride and sodium hydroxide (p. 324)
B. 22, R. 668 ; 24, R. 791).
An elementary analysis will not yield a positive conclusion as to the number
of acyl groups that have entered compounds like those just mentioned. This is
ascertained by first hydrolyzing them with titrated alkali solutions, or, better,
with magnesia (B. 12, 1531). Or, the acetic esters are decomposed by boiling
them with dilute sulphuric acid. The acetic acid that distils over is then titrated
(A. 220, 217 ; B. 23, 1442). The presence of hydroxyl in the dextroses may also
DC proved by means of phenylisocyanate, with which they form carbanilic esters
[B. 18, 2606 ; C. 1904, I. 1068).
(5) Alkyl sulphuric acids result entreating the dextroses with chlorosulphonic
icid, C1HSO3. This is similar to the behaviour of alcohols when exposed to like
xeatment (B. 17, 2457).
The following reactions show the aldehyde and ketone character of
' :he hexoses :
(1) By reduction (action of sodium amalgam) they become changed
' nto hexahydric alcohols. d-Mannose and d-lsevulose yield d-mannitol
md d-sorbitol, galactose yields dulcitol, and d-sorbitol (and d-mannitol)
ieems to result from the reduction of d-dextrose (grape-sugar).
(2) The oxidation of the hexoses does not occur directly upon
sure to the air, but takes place readily by the aid of oxidizing
628 ORGANIC CHEMISTRY
agents ; hence they show feeble reducing power. They precipitate
the noble metals from solutions of their salts, and even reduce am-
moniacal silver solutions in the cold. A very marked characteristic
is their ability to precipitate cuprous oxide from warm alkaline cupric
solutions. One molecule of hexose precipitates about five atoms of
copper, as Cu2O. This is the basis of the gravimetric and volumetric
method for the estimation of the dextroses by means of Fehling's
solution. Only maltose and lactose, of the di- and polysaccharides,
act directly upon the application of heat. The others must be first
converted into dextroses (p. 657).
Fehling's solution is prepared by dissolving 34*65 grams of crystallized copper
sulphate in water, then adding 200 grams Rochelle salt and 600 c.cm. of NaOH
(sp.gr. i -1200), and diluting the solution to i litre. 0*05 gram of hexose is required
to reduce completely 10 c.c. of this liquid. The end reaction is rather difficult
to recognize, hence it is frequently recommended to estimate the separated
cuprous oxide gravimetrically (B. 13, 826 ; 27, R. 607, 760 ; 29, R. 802). Consult
B. 23, 1035, for Soldaini's suggestion of using a copper carbonate solution for
the estimation of the hexoses.
The oxidation-products of the hexoses formed by the action of Fehling's
solution varies according to the concentration, and consist partly of penta-
hydroxycarboxylic acids (p. 647) and partly of acids of lower carbon content
down to formic and carbonic acids (A. 357, 259).
The hexoses are converted into their corresponding monocar-
boxylic acids (p. 647) by moderated oxidation with chlorine and
bromine water, or silver oxide. The ketoses are more stable than
the aldoses towards bromine and iodine solutions.
More energetic oxidation changes them (as well as nearly all carbo-
hydrates) to saccharic or mucic acids. Lactose yields both acids at
the same time.
(3) The aldohexoses produce a red coloration in a sulphite-fuchsine solution
(Schiff's reagent), whilst the ketohexoses, like laevulose and sorbinose, do not
show this reaction (B. 27, R. 674). The penta-acetyl and pentabenzoyl deriva-
tives of the dextroses and galactoses no longer show the aldehyde character
(B. 21, 2842 ; 22, R. 669). Hence, it is supposed that the hexoses possess a
constitution like ethylene oxide or a lactone (B. 21, 2841 ; 22, 2211 ; 23, 2114
26, 2403 ; 28, 3080).
(4) The aldoses yield mercaptals with mercaptans, in the presence
of hydrochloric acid (B. 27, 673).
(5) Oximes are produced when alcoholic hydroxylamine acts or
the hexoses. To break down the aldoses, the acetyl hydroxy-acid
nitriles, obtained from the aldoximes and acetic anhydride, are split
into hydrocyanic acid and acetyl pentoses (p. 617) (B. 24, 993 ; 26
730).
(6a) Osamines are formed when the hexoses are acted on with mcthy
alcoholic ammonia.
(66) The hexoses and aniline, as well as its homologues, yield the anilides — e.g
dextrose anilide, CH2OH[CHOH]4CH : NC6H0, which form cyanides with HNC
—e.g. anilidodextrose cyanide, CH2OH[CHOH]4.CH.(CN)NHC6HB (B. 27, 1287).
(7) Hydrazine converts the aldohexoses into aldazines, and the ketohexosei
into ketazines (p. 228) B. 29, 2308).
(8) The phenylhydrazine derivatives are especially interesting
(pp. 213, 356). (a) If one molecule of the phenylhydrazine, a:
HEXOSES 629
acetate, is allowed to act, the first product will be a hydrazone, C6H12O5.-
(N.NH.C6H5). This class of compounds dissolves readily in water
(with the exception of those derived from the mannoses and the higher
dextroses, B. 23, 2118). They generally crystallize from hot alcohol
in colourless needles. Cold concentrated hydrochloric acid resolves
them into their components. Benzaldehyde is also an excellent
reagent for the decomposition of the phenyfhydrazones (A. 288, 140).
With unsym.-diphenylhydrazine the slightly soluble diphenylhydrazones are
mainly formed (B. 23, 2619, etc.). Benzyl phenylhydrazine is very well suited
for the preparation of pure sugars : the benzyl phenylhydrazones are decomposed
by formaldehyde, whereby the sugar is liberated and formaldehyde benzyl phenyl-
hydrazone, m.p. 41°, is formed (B. 32, 3234). Also, unsym.-methyl phenyl-
hydrazine, bromophenylhydrazine, and ^S-naphthylhydrazine have been recom-
mended from time to time for the precipitation and separation of the sugars
(B. 35, 4444, etc.).
(b) In the presence of an excess of phenylhydrazine the hexoses,
like all dextroses, combine with two molecules of it upon application
of heat and form the osazones (E. Fischer) :
C«H1806 + 2H2N.NH.C4Hf=C6H1004(N.NH.C6H6)a+2HaO-fH2.
Dextrosazone.
The reaction is carried out by adding two parts of phenylhydrazine, two
parts of 50 per cent, acetic acid, and about twenty parts of water to one part of
dextrose. This mixture is digested for about one hour upon the water bath.
The osazone then separates in a crystalline form (B. 17, 579 I 20, 821 ; 23,
2117). In this reaction a hydrazone is first produced, and one of its alcohol
groups, adjacent to either an aldehyde or ketone group, is oxidized to CO, two
hydrogen atoms in the presence of excess of phenylhydrazine appearing as aniline
and ammonia ; the aldehyde- or keto-group, which is formed, reacts further
on a second molecule of phenylhydrazine. One and the same dextrosazone,
CH2OH.(CHOH)3.C(N2HC,H6).CH(N2HC8H6) (B. 23, 2118), is thus obtained
from d-mannose, d-dextrose, and d-laevulose. This would indicate that the
four carbon atoms which did not enter into reaction with phenylhydrazine
contain the atoms or groups of atoms with which they are combined similarly
arranged,
It is of importance in the separation of aldoses and ketoses that with
unsym.-alkyl phenylhydrazines, such as a-methyl phenylhydrazine, only the
ketoses yield the yellow methyl phenyl osazones, whilst the aldoses give the simple
colourless hydrazones (B. 35, 959, 2626).
The osazones are yellow-coloured compounds (see Tartrazine, p. 608). They
are usually insoluble in water, dissolve with difficulty in alcohol, and crystallize
quite readily. When dextrosazone is reduced with zinc dust and acetic acid it
becomes converted into isodextrosamine (p. 637). Nitrous acid converts the
latter into Isevulose (B. 23, 2110). The reformation of the hexoses from their
osazones is readily effected by digestion with concentrated hydrochloric acid ;
they are then resolved into phenylhydrazine and the osones (B. 22, 88 ; 23,
2120 ; 35, 3141):
C6H1004(N2H.C6H6)2+2HaO=CHaOH.(CHOH)3.CO.COH+2N2H3.C6Hi.
Dextrosazone. Dextrosone.
The osones dissolve readily in water, and have not been obtained pure.
They are also formed from aldoses and ketoses directly by oxidation with H2O,
in presence of ferrous salts (C. 1902, I. 859). They combine, like keto-aldehydes,
with two molecules of phenylhydrazine and form osazones. They are converted
into ketoses by reduction, as when digested with zinc dust and acetic acid. In
this way fructose is prepared from dextrosazone (B. 3, 2121).
The osones, like all orthodicarbonyl compounds, yield quinoxalmes (B. 23,
2121) with the orthodiamines. The dextroses also combine directly with the
ortho-phenylene diamines (B. 20, 281).
630 ORGANIC CHEMISTRY
(c) Benzoyl hydrazide, or benzhydrazide, NH2NH.COC6H5, combines with
the aldohexoses to benzosazones, which contain four benzhydrazide residues
(B. 29, 2310):
C.Hia06+4NH2NH.COC6H5=CeH60,(N.NH.COC6H6)4+4H20 + 3H2.
Synthetic and Degradation Reactions of the Hexoses.
(1) Being aldehydes or ketones, the hexoses combine with hydro-
cyanic acid, forming cyanhydrins, which yield monocarboxylic acids
(p. 615). Their lactones can in turn be reduced to aldoses, whereby
the synthesis of the monoses is achieved. Usually in the hydrogen
cyanide addition the nitriles of both the acids possible theoretically
are produced, but not in equal amounts.
These two reactions: (i) the hydrogen cyanide addition to the aldoses, and
(2) reduction of the lactones of the hydroxycarboxylic acids, obtained from the
nitriles, by means of sodium amalgam make possible the genetic connection of
the following aldoses (B. 27, 3192) :
.1-Mannose > 1-Mannoheptose
1-Arabinose ^
"^1- Dextrose
vl-Idose
1-Xylose <J
•^1-Gulose
Rhamnose >-d-Rhamnohexose > Rhamnoheptose > Rhamno-octose
d-Mannosc >-d-Mannoheptose >• -Manno-octose - — >• d-Mannononose
a-Gluco-octose >~ Glucononose
,a-Glucoheptose ^
d- Dextrose <Q ~^#-Gluco-octose
^/?-Glucoheptose
, a-Galaheptose >Galaoctose
d-Galactose g
^^8-Galaheptose
(2) The degradation of the aldohexoses to aldopentoses through their oximes,
and by oxidation with HaOs has already been discussed as a special case of a
general reaction (p. 618).
(3) The behaviour of the hexoses with alkalis, such as the hydroxides of sodium,
calcium, lead, zinc, etc., is noteworthy. Dilute alkalis strongly depress the
optical rotation of the naturally occurring hexoses, as a result of partial isomerisa-
tion to the stereomeric aldoses and ketoses as far as the point of equilibrium (see
B. 28, 3078 ; A. 357, 294). Mannose, dextrose, and lavulose yield a mixture of
these three hexoses, together with \lf-lavulose and glutose (or $-ketohexose ?) ;
similarly, galactose may yield l-sorbose, d-tagatose, talose, and galtose (or 3- keto-
hexose ?).
Longer action of alkalis decomposes this mixture of hexoses mainly into
lactic and other acid (B. 41, 1009). It is probable that the formation of lactic
acid results from the initial formation of glyceraldehyde, which loses oxygen and
is changed into methyl glyoxal (p. 348), which in turn changes into lactic acid :
CH2(OH)CH(OH)CH(OH) CH2(OH)CH(OH).CHO - — >
CH2(OH)CH(OH)CO > CH2(OH)CH(OH).CHO >
3-Ketohexose (see above). Glyceraldehyde.
CHSCO.CHO > CH3CH(OH)CO,H
CH3CO.CHO > CH8CH(OH)COOH
Methyl Glyoxal. Lactic Acid.
The formation of methyl glyoxal, according to the above scheme, is made
the more probable by the action of zinc ammonium hydroxide on dextrose pro-
ducing methyl glyoxaline, which should be prepared from methyl glyoxal and
ammonia (p. 346) (B. 39, 3886).
ALDOHEXOSES 631
In addition to the products of reaction between hexoses and alkalis, there
are also formed — particularly when lime-water is employed — saccharic acids
(p. 620), the production of which results partly from an intra- molecular wandering
of oxygen, and also in a change of the form of the normal carbon chain (comp.
A. 357, 294 ; B. 41, 469, 1012).
If air be passed through an alkaline solution of the hexoses, or if HaOa be
added, mainly formic acid is formed, together with higher molecular non-volatile
acids, the formation of which is explained by partial decomposition of the hexose
into formaldehyde and the oxidation of the latter into its acid (B. 39, 4217) (see
also p. 628 ; Fehling's solution).
(4) Fermentation of the Hexoses. — The ready fermentation of the
hexoses when exposed to the action of schizomycetes is characteristic
of them. They undergo various decompositions.
(a) The alcoholic fermentation of the hexoses is the most important
decomposition of some of the aldohexoses which is induced by yeast
cells. d-Dextrose or grape-sugar, d-mannose, d-galactose, and the
ketohexoses, d-fructose or fruit-sugar, are acted on in this manner.
This subject was examined in detail under ethyl alcohol (p. 112).
The other hexoses are not altered by the yeast fungi (B. 27, 2030).
(b) In the lactic acid fermentation, the hexoses, lactose, and gums decompose
directly into lactic acid :
C6H12Ofl=2C3H(tO,
the active agents being various kinds of fission-fungi — schizomycetes, bacilli,
and micrococci. Decaying protein matter (decaying cheese) is requisite for
their development, which only proceeds in liquids which are not too acid
(p- 363). The temperature most favourable varies from 30-50°. Prolonged
fermentation causes the lactic acid salts which are formed to undergo
(c) Butyric acid fermentation, which is due to the action of other bacilli (p. 259).
This fermentation is explained chemically by the decomposition of lactic acid
into formic acid and acetaldehyde (p. 199), the condensation of the latter into
aldol (p. 338) which changes into butyric acid with the intra-molecular wandering
of an oxygen atom :
CH3CHOH H CH3CHO CH3CHOH CH3CHa
COOH 2COOH HOC.CH, HOC.CHa HOaC.CHa
(d) Citric Acid fermentation of dextrose (p. 610).
(e) In mucous fermentation chains of cells are to be found, which convert
dextrose into a mucoid, gummy substance, with the generation of COa. d-Manmtol
and lactic acid are also formed.
2A. ALDOHEXOSES
(i) Mannose, C6H12O6, is the aldehyde of mannitol. Like the
latter, it exists in three forms (p. 610) : dextro-, laevo-,. and inactive
[d+1] mannose (spacial formulae, p. 641 ; constitution, p. 644).
d-Mannose, Seminose, m.p. 136°, was first prepared by oxidizing ordinary
d-mannitol, together with d-fructose, with platinum black or nitric £ 1 (tt.
22, 365). It is also obtained from salep mucilage (from salep, the 1
certain orchids), and most easily from seminine (reserve-cellulose), occurring »
different plant seeds, particularly in the shells of the vegetable ivory nut, when
this is boiled with dilute sulphuric acid (hence called semtnose) (B. 22, 609, 3218).
d-Mannonic acid yields it upon reduction. It reduces Fehhng 's solution, a
is fermented by yeast (B. 22, 3223). When treated with alkalis jt changes
partly to d-dextrose and d-fructose (p. 630). Its hydrazone, m.p. 195 . dlsso^'
with difficulty in water. Benzaldehyde decomposes it into pure crystallized
d-mannose (B. 29, R. 913). Its osazone, C6H10O4(N2HC.H6)a, is identical with
632 ORGANIC CHEMISTRY
d-dextrosazone. d-Mannosoxinte, m.p. 184° (B. 24, 699). Nascent hydrogen
converts it into d-mannitol. Bromine oxidizes it to d-mannomc acid. Hydro-
cyanic acid causes it to pass into d-mannoheptonic acid (p. 651).
Methyl d-Mannose, C,HnO6.CH8, m.p. 190°, [a]f>=+79'2 (B. 29, 2928);
pentanitrate, m.p. 81° (B. 31, 76)- .
1-Mannose results when 1-mannomc lactone is reduced (p. 649 ; B. 23, 373).
It is very similar to the preceding compound, but is laevo rotatory, and is fer-
mented with more difficulty. Its hydrazone, m.p. 195°, also dissolves with
difficulty It unites with two molecules of phenylhydrazine to form 1-dextro-
sazone It becomes converted into 1-mannitol by reduction (B. 23, 375). Methyl
l-Mannose, m.p. 190°, [a]f =-79'4° (B. 29, 2929).
[d+1] Mannose is formed (i) by the oxidation of a-acritol or [d+1] manmtol
(p. 623), which can be obtained by the reduction of synthetic a-acrose or [d+1]
fructose ; (2) by the reduction of inactive [d+1] mannonic lactone ; (3) by the split-
ting of a mixture of d- and 1-mannose phenylhydrazone by formaldehyde (C. I9°3.
I. 1217). It is quite similar to the two preceding compounds, but is inactive.
Its hydrazone, m.p. 195°, dissolves with difficulty, and is inactive. Its osazone
is [d+l]-dextrosazone, identical with a-acrosazone. Yeast decomposes it, the
d-mannose is fermented, and 1-mannose remains (B. 23, 382). Methyl [d+1]
Mannose, m.p. 165°, is obtained from the solution of equal quantities of its
components at 15°. Below 8° the components crystallize out separately (B. 29,
2929).
(2) Dextrose, C6H1206, is probably the aldehyde of sorbitol, and
occurs as dextro-, laevo-, and inactive [d+1] dextrose (p. 642).
d-Dextrose, or Grape Sugar, formerly called glucose, m.p. with
one molecule of water 86°, anhydrous, 146°, occurs (with Isevulose)
in many sweet fruits and in honey ; also in the urine in Diabetes mellitus.
It is formed by the hydrolytic decomposition of polysaccharides
(sucrose, starch, cellulose) and glucosides. It is prepared on a large
scale by boiling starch with dilute sulphuric acid (see B. 13, 1761).
The synthesis of dextrose has been made possible by the production of
dextrose in the reduction of the lactone of d-gluconic acid (p. 637).
Commercial dextrose is an amorphous, compact mass, containing only about
60 per cent, dextrose, along with a dextrin -like substance, gallisin, C12H24O10,
which is not fermentable (B. 17, 2456).
The best method for preparing pure crystallized dextrose consists in adding
to 80 per cent, alcohol mixed with T'5 volume of fuming hydrochloric acid, finely
pulverized sucrose, as long as the latter dissolves on shaking ( J. pr. Ch. [2] 20, 244).
Dextrose crystallizes from water at the ordinary temperature, or
dilute alcohol, in nodular masses, with one molecule of water, which it
loses at 110°. At 30-35° it crystallizes from its concentrated aqueous
solution, and from its solution in ethyl or methyl alcohol, in anhydrous,
hard crusts (B. 15, 1105).
Dextrose is not quite as sweet to the taste as sucrose, and is employed
to " improve " wines. <*
When the ordinary crystalline dextrose is dissolved in water without the
assistance of heat, it shows [a]D=+io6° ; if it be boiled for twenty-four hours,
or if a trace of alkali be added to it the rotation falls to one half, [a]D=+53-
An equilibrium is here set up, and the more highly rotating a-dextrose can be
separated. But if melted dextrose be heated to 110° another modification —
y-dextrose, [a]D=+22'6° is obtained, which, in aqueous solution, slowly rises
to [a]o=+53°, In pyridine solution dextrose (m.p. 146°) also exhibits birota-
tion ; if this solution be treated with acetic anhydride at o° mainly a-pentacetyl
dextrose (p. 634) will be obtained. If, however, the solution be heated till it
shows the smaller angle of rotation, then jS-pentacetyl dextrose will be obtained
ALDOHEXOSES 633
by the same reagent. Further, the highly-rotating form of a-methyl glucose
(below), when hydrolyzed by the ferment malta.se, yields the more highly
rotating a-dextrose ; the lower /?-form of methyl dextrose gives, with emulsin,
the lower rotating y-dextrose.
It is, therefore, probable that there are two interconvertable stereomeric
forms of dextrose having a alkylene oxide or lactone structure
CH2(OH)CH(OH)CH(0)CH(OH)CH(OH)CH(OH)
from which the stereomeric alkyl dextrose, pentacetyl dextrose etc are
derived (A. 331, 359).
In general, dextrose shows all the properties of the aldoses ; syn- and anti-
fa- and fi-) d-dextrose phenylhydrazine, m.p. 160° and 141°, is laevo-rotatory (A
362, 78).
d-Dextrosazone, a- variety, m.p. 145°; £- variety m.p. 205° (B. 41, 75)
is laevo-rotatory in aqueous solution. It may also be prepared from
d-mannose and d-fructose, as well as from dextrosamine and isodextro-
samine. Concentrated hydrochloric acid converts d-dextrosazone into
phenylhydrazine and dextrosone, C6H10O0 (p. 629) ; which regenerates
d-dextrosazone with two molecules of phenylhydrazine. It is a non-
fermentable syrup (C. 1902, I. 895), and if it be reduced with zinc
and acetic anhydride, is converted into d-fructose (B. 22, 88).
Dextrose is converted, by reduction with sodium amalgam, into d-sorbitol
with some d-mannitol, by acid oxidation, into d-gluconic acid and d-saccharic
acid. Alkalis convert it partly into d-mannose and d-fructose (B. 28, 3078)
together with ^r-fructose and glutose (p. 630) ; prolonged action of alkalis produces
lactic and other acid products (p. 630).
Milk of lime converts dextrose partially into saccharic acid (p. 620). Alkalis
and benzhydrazide break up the dextrose molecule, and form benzoyl osazone of
glyoxal and methyl glyoxal (B. 31, 31). Ammonium zinc hydroxide gives methyl
glyoxaline (p. 630). For the products of alkaline oxidation of dextrose, see pp. 628,
631, and B. 27, R. 788.
The quantitative determination of dextrose may be effected by means of
alkaline mercury cyanide and mercury potassium iodide solutions (B. 39, 504).
Saccharates. — With barium and calcium hydroxide solutions dextrose forms
saccharates, like C,Hi2O8.CaO, and C8H12O6.BaO, which are precipitated by
alcohol. With NaCl it forms large crystals, 2C<Hi2O8.NaCl+H2O, which some-
times separate in the evaporation of diabetic urine.
Alkyl d-Glucosides. — The glucosides are the ethereal derivatives of the
dextroses. Those of dextrose particularly are frequently found in the vegetable
kingdom. They generally contain the residues of aromatic bodies, and therefore
will be discussed later. The simplest glucosides are the alkyl ethers of the sugars,
which are produced in the action of HC1 on alcoholic sugar solutions (B. 28,
1151). Fehling's solution and phenylhydrazine at 100° do not affect the alkyl d-
dextroses. However, they are decomposed into their components when boiled
with dilute acids, or by ferments (p. 631 ). These properties argue for the alkylene
oxide formulae for the alkyl dextroses (p. 632) :
a- and fi-Methyl Dextrose, C6HuO8.CHs,m.ps. 165° and 107°, are stereochemi-
cally different, the a-compound being dextro-rotatory [a]D+ = i57'6°, thejS-body
being laevo-rotatory [a]D= —31 '85° (B. 34, 2899). They are formed together by the
action of hydrochloric acid and methyl alcohol on dextrose, and can also be obtained
from a- and /?-aceto-chloro- orbromo-dextrose, methyl alcohol and silver carbonate,
and hydrolyzing the resulting tetra-acetyl methyl dextrose. jS-Methyl dextrose
is formed from dextrose, dimethyl sulphate and alkate (B. 34, 957, 2885 ; C. 1905,
I. 1593). The a-compound is decomposed by invertin, but not the /J-substance,
which, however, is attacked by emulsin (B. 27, R. 885 ; 27, 2479, 2985 ; 28,
1145). If a-methyl dextrose be alkylized by means of silver oxide and iodo-
methane in methyl alcohol there is formed, among other compounds, a-Methyl
Tetramethyl Dextrose, b.p.]7 145°. Hydrolysis converts this into Tetramethyl
Dextrose, CH.OCHjCH^CHgJCHCOJCHCOCH^CHfOCH^CHOH, m.p. 89°, b.p. a,
634 ORGANIC CHEMISTRY
182-185°. It is also found by the hydrolysis of methylated saccharose and
maltose, also from pentamethyl salicin (Vol. II.) (C. 1903, II. 346 ; 1904, II.
891 ; 1906, II. 345 ; 1908, I. 1043). It is a reducing substance, exhibits muta-
rotation, and is converted by oxidation into tetramethyl gluconic lactone.
fi-Phenyl Glucoside, C6HUO6.C6H6, m.p. 175°, is formed from /2-acetochloro-
dextrose and sodium phenolate (B. 34, 2898).
a- and B-Pentacetyl Dextrose, C6H7O(OCOCH3)6, m.ps. 112° and 131°.
a- zndB-Acetochlorodextrose, C6H7O(OCOCH3;4C1, m.ps. 64° and 74°.
a- and ft-Aceiobromodextrose, CaH7O(OCOCH3)4Br, m.ps. 80° and 89°, are closely
connected with the a- and j8-alkyl d-dextroses and must therefore possess a similar
structure, a- and jS-pentacetyl dextrose, which have lost theiraldehidic character
are formed from dextrose and acetic anhydride with zinc chloride, sodium acetate
or pyridine (see above) ; zinc chloride causes the /J- variety to change into the a-
form. When treated with liquid HC1 or HBr one acetyl group is exchanged for
a halogen atom and acetochloro- and acetobromo -dextroses result. The/3-aceto-
halogen-dextroses were first formed directly from dextrose by the action of acetyl
chloride or bromide ; the j8-acetochlorodextrose being also obtained from pent-
acetyl dextrose, PC16 and A1C13. They are remarkable for the reactivity of the
halogen atom, which can readily be replaced by the acetyl, alkoxyl, and O.NO2-
groups. In the latter case, Acetonitrodextrose, C6H7O(OCOCH3)4(.ONO2), m.p.
151°, is formed, which crystallizes well. It is also formed from /J-pentacetyl
dextrose and nitric acid (A. 331, 381). The following formulae express the probable
structure of these compounds, in which the a- and ^S-varieties are considered as
being stereomeric (p. 633) (B. 34, 957, 2885, 3205 ; 35, 833 ; C. 1902, I. 180) :
,CH.OCH, .CH.OCOCH, ,CH.C1 .CH.Br
/! /I /I /I
O (CHOH)2 O (CHOCOCH3)2 O (CHOCOCH,), O (CHOCOCH8),
\ I \ | \ I \l
\CH \CH \CH XCH
II I I
CHOH CHOCOCH3 CHOCOCH3 CHOCOCH,
I I I
CH2OH - CHjOCOCH, CH2OCOCH3 CH2OCOCH3
Methyl Pentacetyl Acetochloro- and Acetobromo Dextrose.
Glucoside. Dextrose.
d-Dextrose Mercapial, C6H12O6(SC2H5)a, m.p. 127°, is obtained from d-
dextrose, mercaptan, and HC1. d-Dextrose Ethylene Mercaptal, C6H12O5:-
SaC2H4, m.p. 143°. d-Dextrose Trimethylene Mercaptal, C6H12O5:S2C3Ha, m.p.
130°. d-Dextrosebenzyl Mercaptal, CflH12O6(SCH2.CaH5)2, m.p. 133° (B. 29, 547).
Methylene Dextrose, C6Hi0(CH2)Oe, m.p. 187° (B. 32, 2585).
d-Dextrose Monacetone, CaH10Oa:C(CH3),, m.p. 156°. d-Dextrose Diacetone,
C6H8Oa[C(CH8)2]2, m.p. 107° (B. 28, 2496).
d-Chloralose, m.p. 189°, and d-Parachloralose, C8H12C13O6, m.p. 227°, are
two isomeric bodies, produced by the rearrangement of d-dextrose with chloral
<B.27,R.47i; 29, R. 177).
d-Dextrosoxime, C6H12O6NOH, m.p. 137°, when acted on with acetic
anhydride and sodium acetate, yields pentacetyl d-glucononitrile (p. 649), from
which d-arabinose was isolated (p. 618). These are reactions which render
possible the breaking down of the aldoses. Reduction to glucamine (p. 624).
d-Dextrose Aminoguanidine Chloride, C6H12O6.CN4H4.HC1, m.p. 165°, is ob-
tained from d-dextrose and aminoguanidine hydrochloride (B. 27, 971).
d-Dextrose Semicarbazone, m.p. 175° with decomposition (B. 31, 2199, footnote).
d-Dextrosc Aldarine, CH2OH[CHOH]4CH:N— N:CH[CHOH]4CH2OH, is very
hygroscopic (B. 29, 2308).
1-Dextrose, m.p. 143°, is formed when the lactone of 1-gluconic acid is reduced.
It is perfectly similar to dextrose, but is laevo-rotatory, [a]D=— 51-4°. Its
dextrosazone is, however, dextro-rotatory. Its diphenylhydrazone, C,H12O6:N.-
N(C6Hs)2> rn.p. 163°, dissolves with difficulty (B. 23, 2618).
[d+l]-Dextrose results from the union of d- and 1-dextrose, and by the reduc-
tion of [d-f l]-gluconic lactone. \d+\}-Dextrosazone, m.p. 218°, is also formed from
inactive mannose, and from synthetic a-acrose, or [d+l]-kevulose (p. 637) (B. 23,
383, 2620).
(3) Gulose, CH,OHLCHOH]4CHO (space formula, p. 642), the second
KETOHEXOSES 635
aldehyde of sorbitol, is likewise known in its three modifications. They are
formed by the reduction of the lactones of the three gulonic acids (p. 640), and
by further reduction yield the sorbitol. They are syrups and are not fermented
by yeast. The name gulose is intended to indicate their relationship to glucose
(the old name for dextrose), the first aldehyde of sorbitol. 1- and [d-fl] Gulose
Phenylhydrazone, m.p. 143°. \-Gulosazone, m.p. 156°. [d+1] Gulosazone, m.p.
I57-I590.
(4) d- and 1-Idoses are prepared by the reduction of the idonic acids or their
lactones (p. 650). They yield d- and 1-iditolon reduction (p. 624) (space formula,
p. 642).
(5) Galactose, the aldehyde of inactive dulcitol (p. 624), formed by internal
compensation, is known in three varieties. The [d+1] Galactose, m.p. 140-142°,
results from the reduction of the lactone of [d+1] galactonic acid, and when fer-
mented with beer yeast it becomes 1-galactose; phenylhydrazone. m.p. 158-
160° ; osazone, m.p. 206°.
1-Galaetose, m.p. 163° (p. 642), yields dulcitol on reduction, and mucic acid when
it is oxidized ; phenylhydrazone, m.p. 158-160° ; osazone, m.p. 206°.
d-Galactose, CH2OH[CHOH]4CHO, m.p. 160°, is dextro-rotatory and fer-
mentable (B. 21, 1573) (see also p. 642 ; B. 27, 383). It is formed along with
d-dextrose in the hydrolysis of lactose, of galactitol, C9H18O7, a beautifully crystal-
lized body occurring in yellow lupins (B. 29, 896 ; and of various gums (called
galactans) (B. 20, 1003), which nitric acid oxidizes to mucic acid. It is prepared
by boiling lactose with dilute sulphuric acid (A. 227, 224). Dulcitol is formed
by its reduction, and galactonic and mucic acids by its oxidation. HNC and
hydrochloric acid change it to galactose carboxylic acid (p. 651). When heated
with alkalis it is converted into l-sorbose, d-tagatose, d-talose, etc. (p. 636). a-
and /?-Methyl d-Galactose, m.p. 111° and 173-175°. Emulsin decomposes the
second (B. 28, 1429). It stands in the same relation to pentacetyl galactose,
m.p. 142°, acetochlorogalactose, m.p. 76° (82°), acetobromogalactose, m.p. 83°,
and acetonitrogalactoss, m.p. 94°, as do the corresponding dextrose derivatives
(p. 634). a- and ^-Methyl Tetramethyl-Galactose, etc., form, b.p.u 137°, /3-form,
m.p. 45° (C. 1904, II. 892). a- and ^-Galactose Pentanitrate, m.ps. 115° and 72°
(B. 31, 74). Galactochloral, m.p. 202° (B. 29, 544) ; oxime, m.p. 175°, see
Pentacetyl Galactonic Nitrile (p. 650) ; osazone, m.p. 193°. Galactose Amido-
guanidine Chloride (B. 28, 2613). The Ethyl Mercaptal, m.p. 127°; Ethylene
Mercaptal, m.p. 149° (B. 29, 547).
(6) d-Talose, CHaOH[CHOH]4CHO, is formed by the reduction of the lactone
of d-talonic acid (p. 650) (B. 24, 3625). Space formula, p. 643 ; comp. B. 27, 383.
(7) Rhamnohexose, Methyl Hexose, CH3.CHOH(CHOH]4.CHO, m.p. 181°, is
produced by the reduction of rhamnose carboxylic acid ; osazone, m.p. 200°. It
forms methyl heptonic acid with hydrocyanic and hydrochloric acids.
3A. KETOHEXOSES
i. Fructose, CH2OH[CHOH13.CO.CH2OH, occurs as d-, I-, and
[d+1] varieties.
d-Fructose, Laevulose, Fruit Sugar (space formula, p. 646), m.p.
95°, occurs in almost aD sweet fruits, together with dextrose. It
was discovered in 1847 by DubrunfatU. It is formed, (i) together
with an equal amount of dextrose, in the decomposition of sucrose,
and is separated from the latter through the insolubility of its calcium
compound (B. 28, R. 46). As fructose rotates the plane of polariza-
tion more strongly towards the left than dextrose does to the right, the
decomposition of the d-sucrose leads to the formation of a Isevo-rotatory
invert sugar solution (p. 113).
(2) On heating inulin with water to 100° for twenty-four hours,
it is changed exclusively to laevulose (A. 205, 162 ; B. 23, 2107). It
can also be obtained from secalose, a carbohydrate contained in green
rye plants (B. 27, 3525).
(3) It is formed together with d-mannose in the oxidation of
636 ORGANIC CHEMISTRY
d-mannitol ; also (4) from d-dextrosazone, which has been prepared
from d-dextrose, as well as from d-mannose. This method of formation
allies fructose genetically with d-dextrose and d-mannose (p. 631). Hence,
in spite of its laevorotation of [a]D=— 92-3° (A. 25, 166), it is called
d-fmctose. Fructose crystallizes with difficulty, and dissolves with
greater difficulty than dextrose. By reduction it yields d-mannitol
and d-sorbitol ; and when oxidized the products are d-erythronic
acid (p. 598) and glycollic acid. It is partially converted into d-
dextrose and d-mannose by alkalis (p. 631). Heated under pressure
with a little oxalic acid, d-fructose becomes j3-hydroxy-8-methyl-
furfural (B. 28, R. 786). It yields d-fructose carboxylic acid (p. 651)
when treated with hydrocyanic and hydrochloric acids ; this may be
reduced to methyl butyl acetic acid, whereby the constitution of
fructose is proved. Phenylhydrazine and fructose yield d-dextrosazone.
Methyl d-Fructose (B. 28, 1160). Lavulochloral, m.p. 228° (B. 29, R. 544).
a- and fi-Lavulosan Trinitrate, CaH7O5(NO,)3, m.ps. 137° and 48° (B. 81,76).
1- Fructose is produced by fermenting [d+1] fructose (a-acrose) with yeast (B.
23, 389).
[d+1] Fructose or a-Acrose. — The resolvable fructose modification is, by
virtue of its own synthesis, of the greatest importance in the synthesis of sugars
(p. 637).
Historical. — Melhylenitan, the first compound resembling the sugars that
was prepared, was obtained by Butler ow (1861), who condensed trioxy-
methylene (p. 199) with lime-water. 0. Loew (1885) obtained jormose, (CH2OH)2-
C(OH)CH(OH).CO.CH2OH (?) (J. pr. Ch. 33, 321 ; C. 1897, I. 803, 906) in an
analogous manner from hydroxymethylene, and somewhat later the fermentable
methose, by the use of magnesia (B. 22, 470, 478). E. Fischer considers these
three compounds mixtures of different dextroses, among which a-acrose occurs
(B. 22, 360). The latter, together with /S-acrose, is obtained more easily by the
action of barium hydroxide on acroleln bromide, C3H6OBr2 (E. Fischer and
as well as from glyceric aldehyde,CH2OH.CHOH.CHO, or dihydroxyacetone,
/. Tafel (B. 20, 1093)), and by the condensation of so-called glycerose" (p. 534),
CH,OH.CO.CH2OH, by condensation (B. 23, 389, 2131 ; 35, 2630). Reduction
converts [d+1] -fructose or a-acrose into [d+l]-mannitol or a-acritol.
(2) rf-Tagatose, C6H12O8, m.p. 124°, is formed by the action of potassium
hydroxide solution on galactose. It is a ketose. d-Tagatose, galactose, and
talose yield the same osazone, and therefore bear the same relation to one
another as laevulose, dextrose, and mannitol. The above-mentioned alkali
treatment also produces Galtose and
(3) 1-Sorbose, ifj-Tagatose, m.p. 154°, the optical isomer of
d-Sorbose, Sorbinose, C6H12Oe, m.p. 154°. This is obtained from d-sorbitol
(p. 624) by the action of Bacterium xylinum, and unites with 1-sorbose to form
[d +1] sorbose. Reduction with sodium amalgam gives d- and 1-sorbose, as well
as d- and 1-sorbitol and d- and 1-iditol (p. 624). They are to the guloses and idoses
what the laevuloses are to the dextroses and mannoses, and are also ketoses
(C. 1900, I. 758).
Hexose and Pentose Imines and Amines. Ammonia unites with the hexoses
with loss of water to form dextrosimine, mannosimine, galactosimine, and forms
with the pentoses arabinosimine, xylosimine, etc., which are decomposed by acids
into the original aldosr s and ammonia. Isomeric with the hexosimines is
d-Dextrosamine, Chitosamine, CH2OH[CHOH]3CH(NH2)CHO, m.p. 110° with
decomposition (B. 31, 2476), is obtained, with other hexosamines, by hydrolyzing
with hydrochloric acid the chitin of the armour of lobsters, and from the cellulose
of the fungus Boletus edulis ; also from the hydrolysis of proteins, particularly
mucine (see B. 34, 3241, etc). It is therefore of great physiological interest. It
is prepared synthetically by reduction with sodium amalgam of the lactone of
d-dextrosaminic acid, which is formed from d-arabinosimine, hydrocyanic, and
hydrochloric acids (B. 36, 28). It loses water with phenyl cyanate, and forms
a compound, m.p. 211° ; phenylhydrazine produces as dextrosazone. With
SYNTHESIS OF GRAPE SUGAR 637
hyrlroxylamine it forms dextrosaminoxime, m.p. about 122° (B. 31, 2198). Dextros-
amine reacts with nitrous acid to form an imfermentable sugar chitose (B. 35,
4021 ; 36, 2587) ; oxidation with bromine water produces d-dextrosaminic acid
(p. 651) ; with nitric acid isosaccharic acid.
Isodextrosamine, d-Fructosamine, CH,OH[CHOH]8CO.CHNHa, is obtained by
reduction of dextrosazone, and when reduced by sodium amalgam yields d-mannos-
amine and d-glucamine (p. 624).
2B. ALDOHEPTOSES, 2C. ALDO-OCTOSES AND 2D. ALDONONOSES
(E. Fischer, A. 270, 64).
Just as aldohcxoses can be built up from aldopentoses, so can aldo-
heptoses be obtained from aldohexoses, and aldo-octoses from the
aldoheptoses, etc., — e.g. hydrocyanic acid is added to d-mannose,
the lactone of the d-mannoheptonic acid is then reduced to d-manno-
heptose, which, subjected to the same reactions, yields d-manno-
octose (see p. 630) . The heptoses and octoses do not ferment. Heptitols,
octitols and nonitols are formed in their reduction (p. 624).
d-Mannoheptose, C7H14O7, m.p. 135°, is obtained (i) from the lactone of
mannoheptonic acid (p. 651) ; (2) perse'itol yields it when oxidized (p. 625).
Its hydrazone, m.p. about 198°, dissolves with difficulty ; osazone, m.p. about
200° (B. 23, 2231). Sodium amalgam converts it into perseitol (p. 625). 1-Manno-
heptose (A. 272, 186).
a-Dextroheptose, C7H14O7, m.p. about 190° ; osazone, m.p. about 195°.
/3-Dextroheptose (A. 270, 72, 87).
a-Galaheptose, C7HJ4O7, from a-galaheptonic acid, forms an osazone, m.p.
about 200° ; it is converted by hydrocyanic and hydrochloric acids into gala-
octonic acid (p. 652). £-Galaheptose, m.p. with decomposition 190-194°, is
obtained from the lactone of /?-galaheptonic acid (A. 288, 139).
d-Manno-octose, C8H,6O8, is obtained from the lactone of manno-octonic
acid (B. 23, 2234). a-Gluco-octose (A. 270, 95). a-Galaoctose (A. 288, 150).
d-Mannononose, C9Hi8O8, the lactone of d-mannonononic acid, is very
similar to dextrose. It ferments under the influence of yeast ; hydrazone, m.p. 223° ;
osazone, m.p. about 227° (B. 23, 2237). Glueononose (A. 270, 104).
THE SYNTHESIS OF GRAPE SUGAR OR d-DEXTROSE, AND OF FRUIT
SUGAR OR d-FRUCTOSE
As repeatedly mention :d, E. Fischer succeeded in isolating a- Acrose or [d +1]-
Fructose from the condensation products of glycerose (p. 534) and formaldehyde
(p. I99)- In his hands this became the parent substance for the preparation
not only of laevulose or d-fructose, and of dextrose or d-glucose, but also of
d-mannose, of ordinary or d-mannitol, and of ordinary or d-sorbitol, as well as of the
l-modifications corresponding with the bodies just mentioned. The intimate con-
nections between these substances are represented in a diagram given on p. 368.
Following the course laid down in this scheme, which finally culminated in the
synthesis of laevulose and of dextrose, the parent material is found to be a.- Acrose
or [d-\-\]-Fructose. This is produced by the aldol condensation of glycerose,
a mixture of the first oxidation products of glycerol, through the agency of
sodium hydroxide. The reduction o^a-acrose yields a-acritol or [d-\-l]-mannitol,
which is arrived at in the following manner : When ordinary or d-mannitol is
oxidized, d-mannose results, and the latter by similar treatment becomes d-
mannonic acid, which readily passes into its lactone. 1-Arabinose also, by
rearrangement through hydrocyanic acid, becomes \-arabinose carboxylic acid
or \-mannonic acid. Its lactone combines with the lactone of d-mannonic acid
and the product is the lactone of [d+l]-mannonic acid. Upon reducing the
three lactones in sulphuric acid solution with sodium amalgam, d-, 1-, and [d-fl]-
mannose, and [d+l]-mannitol, formed by the further reduction of the latter bodies,
are produced. [d-\-\]-Mannitol is identical with a-acritol or a-acrose. Therefore,
[d-fl] mannonic acid became a very suitable parent substance in realizing the
second synthesis, because a-acrose is very hard to obtain in anything like a desir-
able quantity.
638
ORGANIC CHEMISTRY
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SPACE-ISOMERISM 639
The course from [d +l]-mannonic acid divides in the same way to the d-deriva-
tives as it does toward the 1-compounds, because [d+lj-maniionic acid, like
racemic acid (p. 601), can be resolved by strychnine and morphine into d- and
1-mannonic acid. By the reduction, on the one hand, of the lactone of d-mannonic
acid, d-mannose and d-mannitol are formed, and on the other hand, d-mannose
and phenylhydrazine yield d-dextrosazone, which can also be obtained from
dextrose or d-glucose, and laevulose or d-fructose.
d-Dextrosazone yields dextrosone (p. 629), and the latter by reduction forms
laevulose or d-fructose.
To pass d-mannonic acid to d-dextrose, the former is heated to 140° with
quinoline, whereby it is then partially converted into d-gluconic acid. Conversely,
the latter under the same conditions changes in part to d-mannonic acid (comp.
the intertransformation of d-dextrose and d-mannose, by the action of alkalis,
(p. 630). d-Dextrcse or Grape Sugar is formed in the reduction of the lactone
of d-gluconic acid. d-Sorbitol is produced when grape sugar is reduced. Pro-
ceeding from 1-mannonic acid, the corresponding 1-derivatives are similarly
obtained. \-Fructose is also formed by the fermentation of [d+1] -fructose or
a-acrose, and l-mannose in like manner from [d+l]-mannose.
The gulose groups and the sugar-acids, produced in the oxidation of the
pentahydroxy-n-caproic acids, are also considered in the table. d-Saccharic acid,
resulting from the oxidation of d-gluconic acid, becomes d-gulonic acid on reduc-
tion, and the lactone of the latter by similar treatment changes to d-gulose, the
second aldehyde of d-sorbitol.
The aldohexoses are connected with the aldopentoses (i) through \-arabinose,
which, by the addition of HNC, as already mentioned, passes over into arabinose
carboxylic acid or 1-mannonic acid, and also into \-gluconic acid ; (2) through
the xyloses, the HNC-addition product of which is the nitrile of xylose carboxylic
acid, or l-gulonic acid. Oxidation changes 1-gulonic acid to l-saccharic acid.
l-Gulose and l-sorbitol are formed in the reduction of its lactone.
A. THE SPACE-ISOMERISM OF THE PENTITOLS AND PENTOSES, THE
HEXITOLS AND HEXOSES
The structural formula of the normal, simplest pentitol : CH2OH.CHOH.-
CHOH.CHOH.CH2OH, contains two asymmetric carbon atoms. The CHOH-
group, standing between them is the cause of two possible inactive modifications
instead of one (the case with the tartar ic acids), as the result of an internal com-
pensation. Furthermore, theory permits of two optically active modifications,
and a fifth optically inactive form, arising from the union of the two optically
active varieties. This is the racemic or [d+1] -modification, corresponding with
[d +1] -tartaric acid or racemic acid. These relations are most quickly and readily
made clear by means of the atomic models. The molecule-model is projected
upon the surface of the paper, and then formulae similar to those observed with
tartaric acid are derived :
CO2H COjH CO2H
H.C.OH HO.C.H H.C.OH
HOC.H HC.OH H.C.OH
I ! I
C02H C02H C03H
d-Tartaric Acid. 1-Tartaric Acid. i-Tartaric Acid.
A. Space-isomerism of the Pentitols and Aldopentoses.
The formula! for the four stereochemically different pentitols arise in the same
manner as in the case of the tartaric acids. Suppose these four pentitols to be
oxidized, in one instance the upper CH2OH group, and then the lower similar
group having been converted into the CHO-group, there will result eight stereo-
chemically different aldopentose formulae, none of which passes into any other
640
ORGANIC CHEMISTRY
by a rotation of 180*. The number of predicted space-isomers with n sym-
metric carbon atoms, and with an asymmetric formula may be more easily
deduced by applying the 2" formula of van 't Hoff, in which n indicates the number
of asymmetric carbon atoms. In the aldopentoses «=3, hence 2n=23=8 :
Pentitol (and Tri-
hydroxy-
glutaric Acids'). Aldopentoses (and Pentone Acids}.
(i) CH2OH
(i1) CHO
CH2OH (21)
CHO
H.C.OH
H.C.OH
H.C.OH
HO.C.H
H.C.OH
H.C.OH
H.C.OH or
HO.C.H
H.C.OH
H.C.OH
H.C.OH
HO.C.H
CH2.OH
CH2OH
CHO
CH2OH
Adonitol (Ribotri-
l-Ribose
hydroxyglutaric Acid).
(l-Ribonic Acid).
(2) CH2OH
(3l) CHO
CH.OH (41)
CHO
H.C.OH
H.C.OH
H.C.OH
HO.CH
HO.C.H
HO.C.H
HO.C.H or
H.C.OH
H.C.OH
H.C.OH
H.C.OH
HO.CH
CH2OH
CH2.OH
CHO
CH2OH
Xylitol (Xilotri-
l-Xvlose
d-Xylose.
hydroxyglutaric Acid).
(1-Xylonic Acid).
(3) CH2OH
(51) CHO
CH2OH (61)
CHO
HO.C.H
HO.CH
HO.CH
HO.C.H
H.C.OH
H.C.OH
H.C.OH or
HO.C.H
H.C.OH
H.C.OH
H.C.OH
H.C.OH
CH,OH
CH2OH
CHO
CH2OH
d-Arabitol (d-Tri-
d-Arabino^e
l-Lyxose
hydroxyglutaric Acid).
(d-Arabonic Acid).
(d-Lyxonic Acid).
(4) CH2OH
(7') CHO
CH2.OH (81)
CHO
H.C.OH
H.C.OH
H.C.OH
H.COH
I
I
I
!
HO.C.H
HO.C.H
HO.C.H or
H.COH
HO.C.H
HO.C.H
HO.C.H
HO.CH
CH2OH
CH2OH
CHO
CH2OH
l-Arabitol (1-Tri-
l-Arabinose
hydroxyglutaric Acid).
(1-Arabonic Acid).
The stereoisomeric aldopentoses are capable naturally of uniting to four
inactive double molecules, which can be resolved. The space-formulae (y1) and
(31) for ordinary or 1-arabinose and the xyloses follow from the intimate con-
nection of the 1-arabinoses with 1-dextrose, and the xyloses with 1-gulose, as will
be shown later (p. 645).
If the space formula of inactive xylitol may be considered as established,
there remains but one possible formula for inactive adonitol, the reduction product
of ribose.
Four trihydroxyglutaric acids (p. 621) correspond with the four theoretically
SPACE-ISOMERISM OF THE SUGARS, ETC. 641
predicted pentitols. The same number of eight space isomers as indicated by
the pentoses are possible also for the corresponding monocarboxylic acids
the tetrahydroxy-n-valeric acids, as well as for their corresponding aldehydo-
carboxylic acids, and also for the ketoses of the hexitol series, to which fructose
belongs.
B. THE SPACE-ISOMERISM OF THE SIMPLEST HEXITOLS AND THE SUGAR-
ACIDS, THE ALDOHEXOSES AND THE GLUCONIC ACIDS *
The structural formula of the normal and simplest hexitol :
CH2OH.CHOH.CHOH.CHOH.CHOH.CH3OH, contains four asymmetric carbon
atoms. The theory of van 't Hoff and Le Bel permits of ten possible space-isomeric
configurations for such a compound.
In tartaric acid (p. 606) we started with the point of union of the two asym-
metric carbon atoms in determining the successive series ; and in hexitol also
we begin in the middle of the molecule, and then compare C-atom i with C-atom 4,
and C-atom 2 with C-atom 3. In this manner the ten hexitol configurations given
below have been derived.
If in each of the ten hexitols, in one instance the upper — -CH2OH group,
and in another the lower — CH2OH group 2, have been oxidized to aldoses,
then twenty space-isomeric aldohexoses would result. However, each of the
four hexitols (Nos. I, 2, 3, and 4) yields two aldoses, whose formulae by a rotation
of 1 80° pass into each other, which consequently would reduce the number of
possible space-isomeric aldohexoses to 16.
Ten tetrahydroxyadipic acids (saccharic acids) correspond with the ten space-
isomeric hexitols ; sixteen pentah yd roxy-n.- valeric or hexonic acids (gluconic
acids), and sixteen aldehydotetrahydroxy-monocarboxylic acids (glucuronic
acids) correspond with the sixteen space-isomeric aldohexoses.
The hexitols and the tetrahydroxyadipic acids also have four inactive, racemic
or [d-f-1] -modifications, the aldohexoses, hexonic acids, and aldehydotetra-
hyclroxycarboxylic acids also 8 [d+1] -modifications, as is evident from an inspec-
tion of the formulae in the appended table.
The number of theoretically possible space-isomeric aldohexoses, containing
four asymmetric carbon atoms in the molecule, are more readily derived by
employing the van 't Hoff formula 2n given above with the aldopentoses. This
for 2* would give sixteen space-isomeric aldohexoses.
The space-isomerism of the ketohexoses, containing three asymmetric C-atoms,
has been included in the isomerism of the aldopentoses (p. 640).
Hexitols (and
Saccharic Acids).
Aldohexoses (and
Ilcxonic Acids).
(i) CHjOH
(2) CH2.OH
(ii) CHO
(21) CHO
H.C.OH
HO.CH .
H.C.OH
HO.C.H
j
1
H.C.OH
HO.CH
H.C.OH
HO.C.H
|
|
|
I
HC.C.H
H.C.OH
HO.C.H
H.C.OH
|
|
I
1
HO.C.H
H.C.OH
HO.C.H
H.C.OH
CH2OH
1-Mannitol
CH2OH
d-Mannilol
CH2OH
l-Mannose
CH2OH
d-Mannose
(1-Mannosaccharic
(d-Mannosaccharic
(1-Mannonic Acid).
(d-Mannoiuc Acid).
Acid).
Acid). J
* Die Lagerung der Atome im Raum von /. H. van 't Hoff, deutsch bearbsitet
von F. Herrmann (Vieweg, Braunschweig, i Aufl. 1877 ; 2 Aufl. 1894, and Grundriss
der Stercochemie von Hantzsch (Breslau, Trewendt, 1893). Lehrbuch der Stereo-
chemie, von A. Werner (Fischer, Jena, 1904)-
VOL. I. 2 T
r
642 ORGANIC (
(3) CH2.OH (4) CH.OH
(31) CHO
(4*) CHO
HO.C.H H.C.OH
HO.C.H
H.C.OH
H.C.OH HO.C.H
H.C.OH
HO.C.H
| |
1
1
HO.C.H H.C.OH
HO.C.H
H.C.OH
1 |
I
!
H.C.OH HO.C.H
H.C.OH
HO.C.H
CH..OH CH2.OH
CH2OH
1
CH2OH
1-Iditol d-Iditol
l-Idose
d-Idose
(1-Idosaccbaric Acid). (d-Idosaccharic Acid) .
(1-Idonic Acid).
(d-Idonic Acid).
(5) CHaOH
(51) CHO
(61) CHO
|
1
I
HO.C.H
HO.C.H
H.C.OH
H.C.OH
H.C.OH
H.C.OH
1
1
1
HO.C.H
HO.C.H
HO.C.H
I
1
HO.C.H
HO.C.H
H.C.OH
I
I
1
CH2OH
CH2OH
CH2OH
l-Sorbitol
1-Dextrose
l-Gulose
(1-Saccharic Acid).
(1-Gluconic Acid).
1-Gulonic Acid).
(6) CH2OH
(7l) CHO
(S1) CHO
H.C.OH
H.C.OH
HO.C.H
HO.C.H
HO.C.H
HO.C.OH
H.C.OH
H.C.OH
H.C.OH
I
I
1
H.C.OH
H.C.OH
HO.C.H
I
I
I
CH2OH
CH2OH
CH2OH
d-Sorbitol
d-Dextrose
d-Gulose
d-Saccharic Acid).
(d-Gluconic Acid).
(d-Gulonic Acid).
(7) CH2OH
(91) CHO
(lo1) CHO
1
H.C.OH
H.C.OH
HO.C.H
HO.C.H
HO.C.H
H.C.OH
HO.C.H
HO.C.H
H.C.OH
H.C.OH
H.C.OH
HO.C.H
CH2OH
CH2OH
CH2OH
Dulcitol
d-Galactose
l-Galactose
(Mucic Acid).
(d-Galactonic Acid)
(1-Galactonic Acid)^
(8) CH2OH
(n1) CHO
(I21) CHO
H.C.OH
H.C.OH
HO.C.H
H.C.OH
H.C.OH
HO.C.H
H.C.OH
H.C.OH
HO.C.H
H.C.OH
H.C.OH
HO.C.H
CH2OH
(Allomucic Acid 7).
CH,OH
CH.OH
(9) CH.OH
H.C.OH
H.C.OH
H.C.OH
HO.C.H
SPACE-ISOMERISM OF THE SUGARS, ETC. 643
CHO
H.C.OH
HO.C.H
HO.C.H
HO.C.H
CH,OH
CHO
HO.CH
H.C.OH
H.C.OH
H.C.OH
CHaOH
(1-Talomucic Acid).
(10) CH,OH
HO.C.H
HO.C.H
HO.C.H
H.C.OH
CH.OH
d-Talitol (d-Talomucic Acid).
(I31) CHO (i4t)
H.C.OH
H.C.OH
H.C.OH
HO.C.H
CH,OH
(151) CHO (i6»)
HO.C.H
HO.C.H
HO.C.H
H.C.OH
CH,OH
d-Talose (d-Talonic Acid).
To render rational names possible, E. Fischer has proposed to indicate the
configuration by the sign + or — . These are not intended to show the influence
of the individual asymmetric carbon atom upon the optical properties of the
molecule, as van 't Hoff formerly expressed it, but merely the position of a sub-
stituent upon the right or left side of the preceding configuration formulae. (See
also B. 40, 102.) The formula should be so viewed that in the sugars the aldehyde
or ketone group, and in the monobasic acids the carboxyls stand above. The
numbers begin above, and the sign -f- or — represents the position of hydroxyl, e.g. :
Grape Sugar, d-Dextrose=Hexanepentolal -1 1- + (Formula yl).
d-Gluconic Acid . «=Hexanepentol acid -\ + + (Formula y1).
Laevulose, d-Fructose »=Hexanepentol-2-one 1- -{-.
"In the case of symmetrical structure, — as it exists, for example, in the
diacids and alcohols of the sugar group, — there is no favoured position ; con-
sequently, presuming that the numbering invariably proceeds from the top down,
we get a doubled steric designation," e.g. :
d-Saccharic Acid . . «=Hexanetetrol diacid H H+ or— 1
Dulcitol «=Hexanehexol . -f hor hH
Derivation of the Space-formula for d-Dextrose or Grape Sugar, the most
important aldohexose. The following relations arranged first in the diagram
are the basis of this derivation :
d-Gulose •< — d-Gulolactone •< — d-Gulonic Acid
I. d-Sorbitol
d-Dextrose -4- d-Gluconolactone -<- d-Gluconic Acid
II. d-Dextrose — > d-Dextrosazone -< — d-Mannose
rd-Mannitol
"d-Saccharic
Acid
III. d-Fruc
d-Sorbitol
IV. 1-Arabitol^ 1-Arabinose
Xylitol •< Xylose
Dextrosazone
1-Mannonic Acid
1 Arabinose Carboxylic Add
1-Gluconic Acid —
1-Gulonic Acid —
Xylose Carboxylic Acid,
1-Dextrose
1-Gulose.
644 ORGANIC CHEMISTRY
Diagram I shows that d-dextrose or grape sugar and d-gulose yield the same
d-saccharic acid. Hence it follows that d-saccharic acid and the d sorbitol corre-
sponding with it cannot have the formulae (i), (2), (3), (4) (p. 641), because it is
only the hexitols and saccharic acids, (5), (6), (7), (8), (9), (10), which yield two
space-isomeric aldohexoses each. The formulae (7) and (8) of the six space-
formulas represent, by virtue of internal compensation, optically inactive
molecules, which therefore disappear for the optically active d-saccharic acid and
d-sorbitol.
The fact that d-saccharic acid and d-mannosaccharic acid, d-gluconic and
d-mannonic acids, d-dextrose and d-mannose, d-sorbitol and d-mannitol, only
differ by the varying arrangement of the univalent atoms or atomic groups with
reference to the carbon atom, which in d-dextrose and d-mannose is linked to
the aldehydo-group, makes, it possible to decide between the stereoisomeric
formulae (5) and (6), (9) and (10) ; for d- and 1-saccharic acid, d-mannose and
d-dextrose, yield the same osazone. diagram II (p. 643). 1-Arabinose treated with
hydrocyanic and hydrochloric acids gives rise to both 1-mannonic or 1-arabinose
carboxylic acid, and 1-gluconic acid (diagram IV, p. 643). The same relations
which are observed with 1-mannonic and 1-gluconic acid prevail naturally
with their stereoisomers — d-mannonic acid and d-gluconic acid. A mixture of
d-mannitol and d-sorbitol is obtained by the reduction of d-fructose.
Assuming that d-sorbitol and d-saccharic acid possessed the space-formulae
(9) or (10) (p. 643) :
(9) CH2OH (10) CH2OH
H.C*.OH HO.C.H
i !
H.C.OH HO.C.H
I I
H.C.OH HO.C.H
H.OC.H H.C*.OH
I I
CH2OH CHaOH,
then d-mannitol, and also d-mannosaccharic acid, would have the formulae
(7) or (8) :
(7) CH2OH (8) CH2OH
H.C.OH HC*.OH
I I
HO.C.H HC.OH
I I
HO.C.H HC.OH
.OH HC.OH
H.C*.<
:HaOH CH.OH,
because only these formulae differ from (9) and (10) exclusively in the varying
arrangement of the atoms or atom groups with reference to asymmetric carbon
atoms, designated by asterisks. However, formulae (7) and (8) by internal
compensation give rise to inactive molecules, consequently cannot give back the
configuration of d-mannitol and d-mannosaccharic acid.
Thus, for d-sorbitol and 1-sorbitol, d-saccharic acid and 1-saccharic acid there
remain only formulas (5) and (6), from which (6) is arbitrarily selected for d-sorbitol
and d-saccharic acid, and (5) for 1-sorbitol and 1-saccharic acid. " When this
has been done then all further arbitrary selection ceases ; now the formulae for
all optically active compounds connected experimentally with saccharic acid
are regarded as established " (B. 27, 3217). Hence, the space-formula (2) falls
to d-mannitol and d-mannosaccharic acid, and formula (i) to 1-mannitol and
1-mannosaccharic acid, which would also give formulae (2 ) and (i1) to d- and
1-mannonic acids (p. 648).
The aldohexoses (7*) and (81) (p. 642) correspond with d-sorbitol and the
saccharic acid with space-formula (6) :
SPACE-ISOMERISM OF THE SUGARS, ETC. 645
(6) CH2OH (y1) CHO (8*) CH2OH (8^) CHO
I I I I
H.C.OH H.C.OH H.C.OH HO.C.H
|i| .
HO.C.H HO.C.H HO.C.H rotated HO C H
I I I I8o° I
H.COH H.C.OH H.C.OH H.C.OH
III I
H.C.OH H.C.OH H.C.OH HO.CH
III I
CH2OH CH2OH CHO CH.OH
d-Sorbitol (d-Saccharic Add).
In order to obtain the aldehyde group at the top of the formula image, formula
(81) must be turned 1 80°. This converts it into formula (81), and the succession of
the atomic groups attached to the asymmetric carbon atomTs naturally not altered.
The choice between formulae (71) and (81) for d-dextrose and d-gulose still
remains. We are able to determine this if we can select out the space-formulae
for the two stereoisomers — 1-dextrose and 1-gulose. This is possible with a
proper consideration of the genetic relation of the last two bodies with 1-arabinose
and xylose, as represented in diagrams IV and V (p. 643).
The formulae (51) and (6^of the aldohexoses correspond with the formula (5) of
1-saccharic acid. (61) when rotated becomes (61) :
(5) CH2OH ""(51) CHO (61) CH2OH (61) CHO
III I
HO.C.H HO.C.H HO.C.H H.C.OH
III I
H.C.OH H.C.OH H.C.OH H.C.OH
III I
HO.C.H HO.C.H HO.C.H rot°arteVd 180' HO.C.H
HO.C.H HO.C.H HO.C.H H.C.OH
III I
CH2OH CHaOH CHO CH2OH
I-Sorbitol (1-Saccharic Acid).
Remembering that, according to diagram IV (p. 643), it is possible to obtain
d-dextrose from 1-arabinose, and, according to diagram V, 1-gulose from xylose,
then the pentoses mentioned must have the space-formulae which can be derived
for formulae (5') and (6l) by omitting the first of the C*-atoms, by which the
structure becomes asymmetric :
(61) CHO CHO CH2OH
I ! I
H.C*.OH H.C.OH H.C.OH
H.C.OH HO.C.H HO.C.H
HO.C.H H.C.OH CH.C.OH
I I I
H.C.OH CH2OH CH2OH
j Xylose. Xylitol.
CH2OH
1-Gulose.
(51) CHO
HO.C*.H CHO CH,OH
I I I
H.C.OH •< H.C.OH > H.C.OH
HO.C.H HO.C.H HO.C.H
HO.C.H HO.C.H HO.C.H
CH,OH CH.OH Ft'0,11
1-Dextrose. 1-Arabiaose. 1-Arabitol.
646
ORGANIC CHEMISTRY
It is at once seen that the aldopentose corresponding with formula (61) must,
by reduction, yield an inactive pentitol, xylitol (p. 616) — through an internal
compensation. Similarly, the pentose with formula (s1) changes to an optically
active pentitol — 1-arabitol (p. 616). In this manner is fixed not only the configura-
tion for xylitol and xylose, 1-arabitol and 1-arabinose, but it is also demonstrated
that 1-gulose, from xylose, has the formula (61), and 1-dextrose, synthesized from
1-arabinose, the space-formula (51). (81) is the stereoisomeric formula of space-
formula (61), which, therefore, belongs to d-gulose. Formula (7*) corresponds
with space-formula (51), and hence it belongs to d-dextrose. From all this it would
follow that d- and 1-mannoses have formulae (21) and (i1), which facts confirm
that d-dextrose and d-mannose on the one hand, and 1-dextrose and 1-mannose
on the other, pass into the same dextrosazone — i.e. they differ only in the con-
figuration at one asymmetric C-atom.
When it is remembered that d-fructose, by reduction, yields a mixture of
d-mannitol and d-sorbitol,and d-dextrosazone on treatment withphenylhydrazine,
it will be recognized that both it and its corresponding d-arabinose must have
the space-formulae :
CHa.OH
do
HO.C.H
H.C.OH
H.C.OH
CH2OH
d-Fructose.
CHO
HO.C.H
H.C.OH
H.C.OH
CH2OH
d-Arabinose.
The configurations of other ketoses, such as tagatose and sorbose (p. 636), can
similarly be derived.
DERIVATION OF THE CONFIGURATION OF d-TARTARIC ACID
The configuration of d-tartaric acid is evident, according to E. Fischer, from
its production in the oxidation of d-saccharic acid. The formula of the latter has
been previously deduced above. It is in harmony, therefore, with its formation
in the oxidation of methyl tetrose (p. 597), a decomposition product of rhamnose.
The latter, when oxidized, passes into 1-trihydroxyglutaric acid. The a-rhamno-
hexonic acid, obtained from the latter by the hydrocyanic acid addition, yields
mucic acid on oxidation, and the latter, on similar treatment, changes to racemic
acid. Assuming that the methyl group of rhamnose is eliminated in the oxidation
of rhamnohexonic acid, rhamnose would have the following configuration-
formula :
COaH
H.C.OH
H.C.OH
HO.C.H
CO,H
CHO
H.C.OH
H.C.OH
HO.C.H
? CH.OH
CH8
CO,H
HO.C.H
H.C.OH
-> H.C.OH
HO.C.H
?CHOH
1_
CO,H
HO.C.H
H.C.OH
H.C.OH
HO.C.H
CO,H
CO.H
HO.C.H
H.C.OH
CO,H
CO,H
H.C.
OH
HO.C.H
COaH
l-Trihydroxy-
glutaric
Acid.
Rhamnose.
a-Rhamnose
Carboxylic
Acid.
Mucic Acid.
Racemic Acid.
This assumption has been proved through the behaviour of the stereoisomeric
/5-rhamnohexonic acid, which results on heating a-rhamnohexonic acid to 140*
PENTAHYDROXYCARBOXYLIC ACIDS
647
with pyridine. All experiences go to show that the two stereoisomeric rhamno-
hexonic acids only differ in the arrangement or position of the carboxyl group
in direct union with the asymmetric carbon atom. Had the methyl group not
been split off in the oxidation, but merely changed to carboxyl, then a- and
^-rhamnohexonic acids would have yielded the same mucic acid, because the
asymmetric C-atom linked to carboxyl in a- and /?-rhamnohexonic acid, that
caused the difference in the two acids, would have been oxidized to carboxyl.
/?-Rhamnohexonic acid, however, oxidizes to 1-talomucic acid, which justifies
the preceding assumption, and consequently proves the configuration, even to
the position of the asymmetric carbon atom linked to methyl.
Wohl's procedure permits of the conversion of rhamnose into methyl tetrose,
which is oxidized to d-tartaric acid by nitric acid. Hence, we may suppose that
here the methyl group is split off as in the case of the oxidation of rhamnose
to 1-trihydroxyglutaric acid, and of a-rhamnohexonic acid to mucic acid. This
then demonstrates the configuration of d-tartaric acid (B. 29, 1377) :
CHO
H.C.OH
H.C.OH
HO.C.H
? CH.OH
CHO
H.C.OH
HO.C.H
? CH.OH
Rhamnose.
Methyl Tetrose.
COaH
H.C.OH
HO.C.H
CO8H
d-Tartaric Acid.
C02H
H.C.OH
AH
HO
H.C.OH
H.C.OH
CO,H
d-Saccharic Acid.
4. Hexaketones. Oxalyl Bis-acetyl Acetone, (CH3CQ)2CHCO.CO.CH(CqCH8)a,
is the parent substance of dicyano-bis-acetyl acetone, aa^Tetracetyl pBi-Diimino-
butane, (CH3CO)CHC(NH).C(NH).CH(COCH3)S, m.p. 147°, which is prepared
from dicyanomonacetyl acetone (p. 599), acetyl acetone, and a little alcoholate.
Even when boiled in water it is changed into a carbocyclic derivative (A. 332, 146).
5. POLYHYDROXYMONOCARBOXYLIC ACIDS
A. PENTAHYDROXYCARBOXYLIC ACIDS
These acids are produced (i) by the oxidation of the alcohols and
aldoses corresponding with them (B. 32, 2273), by means of chlorine and
bromine water ; (2) by the reduction of the corresponding aldehydo-
acids and lactones of dicarboxylic acids ; synthetically, from the
aldopentoses (arabinose, rhamnose, p. 618) by means of HNC, etc.
This is analogous to the synthesis of glycollic acid from formaldehyde,
and ethylidene lactic acid from acetaldehyde :
CN
<CH(OH)
CHa
CN
[CHOH]4
CHaOH
CHO
CH8
HNC
HC1
aHaO
CHO
[CHOH], —
CH,OH
l-Arabinose.
1-Glucononitrile.
C08H
CHOH
CH3
CO2H
[CHOH]«
CHaOH
l-Gluconic Acid.
1-Arabinose Carboxylic Add.
Behaviour— (i) Being y- and 8-hydroxy-derivatiyes, nearly all of
these acids are very unstable when in a free condition. They lose
water readily and pass into lactones (p. 371) :
-HaO
C.HnO, > C6H100».
648 ORGANIC CHEMISTRY
(2) The capacity of the lactones, but not the acids themselves, to
pass into the corresponding aldohexoses by combination with two
atoms of hydrogen (E. Fischer), is of great importance in the synthesis
of the aldoses (p. 625) :
•H
C6H1008 > C6H120,.
d-Gluconolactone. d -Dextrose.
(3) These acids, when acted on with phenylhydrazine, form characteristic
crystalline phenylhydrazides, C6HuOB.CO.NtH2CflH? (B. 22, 2728). They are
de'composed into their components when boiled with alkalis. They are dis-
tinguished from the hydrazones of the aldehydes and ketones by the reddish-
violet coloration produced upon mixing them with concentrated sulphuric acid
and a drop of ferric chloride.
(4) Heated to 130-150° with quinoline or pyridine a geometric
rearrangement ensues, which, is, however, restricted to the asymmetric
carbon atom in union with the carboxyl (comp. the inter-transformation
of stereomeric hexoses under the influence of alkali, p. 630). It is a
reversible reaction, and therefore yields a mixture of both stereo-
isomers, e.g. (B. 27, 3193) :
d- and 1-Gluconic Acid -^ >- d- and 1-Mannonic Acid.
1-Gulonic Acid -< > 1-Idonic Acid.
d-Galactonic Acid •< ^ d-Talonic Acid.
(5) These acids are reduced to lactones of the y-monohydroxy-
carboxylic acids (p. 374), if they are heated with hydriodic acid.
(6) Oxidation of the hexonic acids or their lactones with hydrogen
peroxide and ferric acetate, causes degradation to the pentoses (comp.
p. 616).
Isomerism. — Spacial isomers of pentahydroxy-n.-caproic acid are as
numerous, according to theory, as the aldohexoses (p. 641), i.e. sixteen
optically active and eight [d-fl] -modifications, which are inactive.
Mannonic Acid, C5H6(OH)5.C02H. The syrup-like acids — d-, 1-,
and [d-}-l]-mannonic acids — yield d-, 1-, and [d-\-l]-mannosaccharic acids
on oxidation (p. 653). They change to lactones on the evaporation of
their solutions ; which by further reduction yield d-mannitol, \-mannitol,
and [d-{-l]-mannitol. [d+\]-Mannitol is identical with a-acritol, the
reduction product of synthetic a-acrose or [d-|-l]-fructose. As [d-f-1]-
mannitol or a-acritol, when oxidized, yields [d+l]-mannose, and the
latter by similar treatment becomes converted into [d-}-l]-mannonic
acid, which can be split into d-mannonic acid and 1 mannonic acid,
the complete synthesis of all bodies of the mannitol series can be
realized through these reactions (p. 637) :
d-MannitoM-d-Mannose •< — d-Mannonolactone
i
d-Mannonic Acid — >• d-Manno saccharic
Acid
a-Acrose->a-AcritoK-[d-f-l] Mannose^-[cl+l]-Mannonic Acid-> [d+l]-Mannosac-
[d+l]-FructoseJd+l]-Man- charic Acid
1-Mannonic Acid ^ 1-Mannosaccha-
•^ ric Acid
l-Mannitol-<-l-Mannose -< 1-Mannonolactone.
d-Mannonolactone, C6H10O6, m.p. 149-153° [a]D=+ 53'8°
1-Mannono actone, ,, 140-150° [a]D=+ 54-8°
[d-j-11-Mannonolactone (C,H10O,)a, m.p. 149-155°.
PENTAHYDROXYCARBOXYLIC ACIDS 649
d- and \-Mannonic Acid Phenylhydrazide, C6H11O6(N2H2.C6HB), m.p. 215°.
[d-}-l]-Mannonic Acid Phenylhydrazide, m.p. about 230° when it is rapidly
heated. The hydrazides are converted into the acids on boiling with barium
hydroxide solution (B. 22, 3221), a reaction which is well adapted for the purifica-
tion of the acids, d- and \-Methylene Mannonic Lactone, (C.H.Og(CHA m.p. 206°
(A. 310, 181).
A very important feature is that a partial conversion of d- and l-
mannonic acid into d- and /- gluconic acids occurs on heating the former
to 140° with quinoline. The last two acids, subjected to the same treat-
ment, change in part into d- and 1-mannonic acids.
This method of preparing d- and l-gluconic acids shows the genetic
connection existing between d- and l-dextrose and the mannitol series, and
thereby renders possible the synthesis of dextrose.
The formation of 1-mannonic acid or 1-arabinose carboxylic acid
(together with l-gluconic acid) from 1-arabinose by means of hydro-
cyanic acid, constitutes one of the transitions which allows of the
synthesis of aldohexoses from aldopentoses :
(l-Mannonic Acid >• 1-Mannonolactone M-Mannose
l-Arabinose<l-Arabinose Carboxylic Acid.
(1-Gluconic Acid >• 1-Gluconolactone M-Dextrose.
Gluconic Acid, CH2OH[CHOH]4C02H, is known in the d-, 1-, and
[d +l]-modifications (B. 23, 801, 2624; 24, 1840) (space formula,
see p. 642).
1. The lactones of these three acids change to d-, l-f and [d-fl]-
dextrose on reduction.
2. By oxidation they become converted into d-, 1-, and [d-fl]-
saccharic acids.
3. When heated to 140° with quinoline they change in part to d-,
1-, and [d+l]-mannonic acids (p. 648). Conversely, d-, 1-, and [d-f-1]-
gluconic acids are obtained by the same treatment from d-, 1-, and
[d+lj-mannonic acids.
The d- and \-phenylhydrazides, CeHnOetNgH^CgHy, m.p. about
200° when they are rapidly heated ; [d-\-\]-phenylhydrazide, m.p. 190°.
d-Gluconic Acid, Dextronic Acid, Maltonic Acid, is formed (i) by
the oxidation of dextrose, sucrose, dextrin, starch, and maltose with
chlorine or bromine water ; and is most readily obtained from dextrose
(B. 17, 1298) ; (2) from d-mannonic acid. Gluconic acid forms a
syrup which, when evaporated or upon standing, changes in part to
its crystalline lactone, C6H10O6, m.p. 130-135°. Sodium amalgam
reduces it to d-dextrose or grape sugar (B. 23, 804). Its barium salt
crystallizes with three molecules of water ; calcium salt with one.
The acid is dextro-rotatory. On the conversion into d-arabinose by
oxidation with H2O2, see p. 618.
Pentacetyl Glucononitrile, C6Hfl(O.C2H3O)BCN (B. 26, 730). Dimethylene
Gluconic Acid, C,H8O7(:CHj)2, m.p. 220°, is prepared from d-gluconic acid and
formaldehyde (A. 292, 31 ; 310, 181).
1-Gluconic acid is formed (i) from 1-mannonic acid (p. 648) and (2) together
with 1-mannonic acid from 1-arabinose by aid of HNC.
[d+l]-Gluconie Acid is obtained from a mixture of d- and l-gluconic acids.
Its calcium salt, which dissolves with difficulty, is obtained, like calcium racemate,
by mixing solutions of d- and 1-calcium gluconates.
Gulonio Acid, CH4OH[CHOH]4CO,H, is known in three forms, which
650 ORGANIC CHEMISTRY
become converted into d-, 1-, and d+1] -saccharic acids (p. 653) when they are
oxidized. The reduction of their lactones produces d-, 1-, and [d-f l]-guloses
(p. 635).
d-Gulonic Acid is obtained by reduction both of glucuronic acid (p. 752)
and d-saccharic acid ; lact&ne, m.p. 181° ; phenylhydrazide, m.p. 148° (B. 24,
526).
1-Gulonic Acid, Xylose Carboxylic Acid, results when xylose is acted on with
HNC. This reaction unites also the aldopentoses with the aldohexoses. 1-Idonic
acid is produced simultaneously, and when heated with pyridine changes partially
to 1-gulonic acid. l-Gulonic Lactone, m.p. 185°, yields 1-xylose when oxidized
with H2Oa (p. 619) ; phenylhydrazide, m.p. 147-149° (B. 23, 2628); 24, 528).
[d+l]-Gulonie Acid readily changes into its lactone, which by crystallization
splits into d- and 1-gulonolactone. Calcium [d+l]-gulonate dissolves with more
difficulty than calcium d- and 1-gulonate ; phenylhydrazide, m.p. i53-I55°
(B. 25, 1025).
1-Idonic Acid is formed together with l-guloni<; acid from xylose, and is
separated by means of its brucine salt from the mother liquor of 1-gulonolactone.
Heated with pyridine to 140°, it changes in part to 1-gulonic acid, and vice versd.
1-Idose is its reduction product (p. 635). d-Idonic Acid, obtained from d-gulonic
acid by means of pyridine, yields d-idose on reduction (B. 28, 1975)-
Galactonic Acid, CHaOH[CHOH]4CO2H, is known in three modifications,
[d+l]~Galactonic Acid results in the reduction of ethyl mucic ester and also of
the lactone of mucic acid ; [d+l]-lactone, m.p. 122-125° ; phenylhydrazide, m.p.
205°. This acid can be resolved by means of its strychnine salt into the 1-salt,
which is more easily soluble in alcohol, and the d-salt, which dissolves with more
difficulty (B. 25, 1256). l-Galactonic Acid resembles in a remarkable degree the
longer-known —
d-Galactonie Acid, Lactonic Acid, CHaOH[CHOH]4CO2H, which isproduced
from lactose, d-galactose, and gum arabic by the action of bromine water ; also,
with d-talonic acid, from d-lyxose cyanhydrin by hydrolysis (B. 33, 2146) . It
can be converted into d-talonic acid, and then be prepared from the latter.
It is converted into mucic acid by oxidation with nitric acid (p. 654). It crystal-
lizes, and at 100°, yields d-galactonic lactone, C,HiaO6, m.p. 91°, which unites
with water of crystallization to form C6H10O6+HaO, m.p. 64° (A. 271, 83).
Acetyl chloride produces Triacetyl Galactonic Lactone Chlorhydrin, C6H6Oa-
(OCOCH3)3C1, m.p. 98° (B. 35, 943). Reduction converts it into the lactone
d-galactose (p. 635); calcium salt, (CeHuO7)2Ca+5H2O ; phenylhydrazide, m.p.
200-205° ; amide, m.p. 175° ; anilide, m.p. 210° (B. 28, R. 606).
Dimethylene Galactonic Acid, CBH7O6(CHa)2CO2H, m.p. 136 (A. 310, 181).
Pentacetyl d-Galactonic Nitrile, b.p. 135°, is formed from d-galactose oxime and
acetic anhydride, and yields, with silver oxide and ammonia, the acetamide
compound of lyxose (p. 619).
d-Talonie Acid, CH2OH[CHOH]4CO2H, results together with hydroxy-
methylene pyromucic acid on heating d-galactonic acid with pyridine or quinoline
to 140-150°. Conversely, d-galactonic acid is obtained from d-talonic acid by
the same treatment (B. 27, 1526). Reduction changes it to d-talose (p. 635).
a-Rhamnose Carboxylic Acid, CH8[CHOH]5COaH, is formed from rhamnose
(see Isodulcitol, p. 619) with HNC, etc. ; lactone, C7H12O6, m.p. 162-168° (B. 21,
2173); phenylhydrazide, C7Hi,O,.N,HaC,H,, m.p. about 210° (B. 22, 2733).
When heated with hydrochloric acid and phosphorus it is reduced to n-heptylic
acid, C7H14OS ; but sodium amalgam changes it into the lactone of methyl hexose
(P- 635) (B- 23, 936). Oxidation produces mucic acid (B. 27, 384).
(3-Rhamnose Carboxylic Acid is formed when the a-compound is heated to
150-155° with pyridine; lactone, m.p. 134-138°; phenylhydrazide, m.p. 170°.
Oxidation converts the /?-acid into 1-talomucic acid (p. 654). Chitonic Acid,
which is produced from chitose (p. 636) and bromine water, and chitaric acid,
C6H10O,, prepared from d-glucaminic acid (see above) and nitrous acid
are probably stereomeric trihydroxymethyl tetrahydrofurfurane carboxylic acid,
HOCH,.CH(0)CH(OH)CH(OH)CHCOtH, since acetic anhydride converts it into
theocrfyJderivative of hydroxymethyl £yrowttc«caarf,CHaCO.O.CHa.C(O):CH.CH:C-
CO2H (Vol. II.), B. 36, 2587). Oxidation with H2O2 and ferrous sulphate degrades
chitonic.acid into.d-arabinose or d-ribose (p. 619)4(6. 35, 4016).
HEXOSE CARBOXYLIC ACIDS 651
Glucosaminic Acid, a-Amino-fiy'oe-tetrahydtoxycaproic Acid, HOCH2[CHOH]3-
CH(NH2)CO2H, is known in d-, 1-, [d+l]-forms. d- and 1-glucosaminic acid
are prepared from d- and 1-arabinosimine (p. 636), hydrocyanic and hydrochloric
acids, and unite to form the less soluble [d+1] acid. d-Glucosaminic acid is also
prepared from d-glucosamine and bromine water. Alcohol and hydrochloric
acid convert it into a lactone-like syrup, which, on reduction with sodium amalgam,
regenerates d-glucosamine. Reduction with hydriodic acid produces a-amino-
caproic acid ; with nitrous acid it forms chitaric acid (see above). It yields
isomeric fi-aminoglucoheptonic acids, CH2OH[CHOH]3CH(NH2)CHOHCO2H,
with hydrocyanic and hydrochloric acids (B. 38, 27, 618).
Galaheptpsaminic Acid, CHaOH[CHOH]4CH(NH)2CO2H, m.p. 240° with
decomposition, is prepared from galactosimine (p. 636) and hydrocyanic and
hydrochloric acids (B. 35, 3801).
B. HEXOSE CARBOXYLIC ACIDS, HEXAHYDROXYMONOCARBOXYLIC ACIDS
Acids of this kind have been obtained from d-dextrose, d-mannose,
d-galactose, and d-fructose by the addition of hydrocyanic acid, and
the subsequent saponification of the nitrile with hydrochloric acid.
(1) Maimoheptonic Acid, is known in three modifications :
d-Mannose Carboxylie Acid, d-Mannoheptonic Acid, CHaOH.[CHOH]5.CO2H,
is obtained from d-mannose (A. 272, 197) ; phenylhydrazide, m.p. about
220° with decomposition ; lactone, m.p. 149°. Sodium amalgam reduces the
lactone to d-mannoheptose, C7H14O7, and then to the heptahydric alcohol
perseitol, C7H18O7 (B. 23, 936, 2226). Hydriodic acid reduces the acid toheptolac-
tone and heptylic acid (see above and B. 22, 370). When oxidized it yields 1-penta-
hydroxypimelic acid (A. 272, 194). \-Mannose Carboxylie Acid is obtained from
1-mannose ; phenylhydrazide, m.p. about 220°; lactone, m.p. 154°. [d+1]-
Mannose carboxylic acid is formed from d- and 1-mannose carboxylic acid, as
well as from [d+]-mannose (A. 272, 184).
(2) a,d-Dextrose Carboxylic Acid, a.d-Glucoheptonic Acid, CHaOH[CHOH]6-
COaH, is formed (i) together with the /3-acid from d-dextrose; (2) on heating
the /S-acid to 140° with pyridine ; (3) by the hydrolysis of lactose- and
maltose carboxylic acids (p. 661) (A. 272, 200) ; lactone, m.p. 140-145°.
Hydriodic acid reduces it to heptolactone and normal heptylic acid. Sodium
amalgam reduces the lactone to dextroheptose (d-glucoheptose). Dimethylene
a-Glucoheptonic Lactone, C7H8(CH2)2O7, m.p. 280°. The acid, when oxidized,
is converted into inactive pentahydroxypimelic acid (p. 655) ; phenylhydrazide,
m.p. 171° (B. 19, 1916 ; 23, 936 ; space-formula, A. 270, 65).
^-Dextrose Carboxylic Acid is formed together with the a-acid from dextrose ;
phenylhydrazide, m.p. 151° ; lactone, m.p. 151°, and yields /?, d-glucophetose
on reduction (p. 637). Dimethylene p-Glucoheptonic Lactone, m.p. 230° (A. 299,
328; 310, 181).
a,d-Galaetose Carboxylic Acid, a-Galaheptonic Acid, CH2OH[CHOH]6CO2H,
m.p. 145°, is produced together with f$-galaheptonic acid from galactose ; lactone,
m.p. 150°. Sodium amalgam changes it into a-galaheptose (p. 637). When
oxidized it yields carboxy-d-galactonic acid (p. 655) (A. 288, 39).
d-Fructose Carboxylic Acid, CH2OH.[CHOH]8C(OH)(CO2H)CH,OH, is obtained
from fructose or laevulose by the action of hydrocyanic acid. It yields tetra-
hydroxybutane tricarboxylic acid when it is oxidized. Its lactone, m.p. 130 ,
when reduced with sodium amalgam two aldoheptoses with branched C-chams
result (B. 23, 937). Reduction with hydriodic acid forms heptolactone and
heptylic acid, C7H14Oa. The latter is identical with methyl n.-butyl acetic acid
(p. 261). Hence it is evident that lavulose is a ketone-alcohol (Kthant, B. 19,
23,451; 24,348).
C. ALDjDHEPTOSE CARBOXYLIC ACIDS, HEPTAHYDROXYCARBOXYLIC ACIDS
d-Manno-octonic Acid, CHaOH.[CHOH]6COaH, has been obtained from
oheptose (p. 637) ; hydroxide, m.p. 243° ; lactone, m.p. about 168 , has
652 ORGANIC CHEMISTRY
a neutral reaction, and a sweet taste. By reduction it forms d-manno-octose
(p. 637). a- and fi-Gluco-octonolactone, m.p. 145° and 186° (A. 270, 93). a-Gala-
octonolactone, from a a-galaheptose (A. 288,149).
D. ALDO-OCTOSE CARBOXYLIC ACIDS, OCTOHYDROXYCARBOXYLIC ACIDS
d-Mannonononic Acid, CH2OH[CHOH]7CO2H, has been obtained from d-
manno-octose ; hydrazide, m.p. 254°; lactone, m.p. 176°. When reduced it
forms d-mannononose (p. 637).
6. TETRAHYDROXY- AND PENTAHYDROXY-ALDEHYDE ACIDS
d-Glueuronie Acid, CHO(CHOH)4COaH, is obtained by decomposing euxanthic
acid (Vol. II.) on boiling with dilute sulphuric acid. Various glucoside-like
compounds of glucuronic acid with camphor, borneol, chloral, phenol, and
different other bodies (B. 19, 2919, R. 762) occur in urine after the introduction
of these compounds into the animal organism. In this change the substances
mentioned combine with the aldehyde group of dextrose, the primary alcohol
group of which is then oxidized. Boiling acids decompose them into their
components. Synthetically, such conjugated glucuronic acid can also be obtained,
r~ ~^j
e.g. Diacetyl Bromoglucurolactone, OCHBrCH(OaC,H3)CH.CHCH(O2C2H3)CqOf
m.p. 90°, the product of reaction between glucuronic lactone and acetyl bromide
reacting with euxanthone (Vol. II.) or phenol (Vol. II.) and sodium alcoholate,
gives rise to euxanthic or phenol glucuronic acid (C. 1905, I. 1086). Glycuronic
acid can be identified in animal secretions by the blue coloured substance, soluble
in ether, which is formed with jS-naphthoresorcinol and hydrochloric acid (B. 41,
1788).
Glucuronic acid forms a syrup, which rapidly passes into the sweet-tasting
lactone, C,H8O,, m.p. 175°. (For derivatives of the same see B. 33, 3315).
Bromine water oxidizes it to saccharic acid. It also appears that when saccharic
acid is reduced glucuronic acid results (B. 23, 937), and by further reduction
d-gluconic acid (p. 649) is formed (B. 24, 525). The acid unites with potassium
cyanide to form the half nitrib of a-glucopentahydroxypimelic acid (p. 655) ;
with three molecules of phenylhydfazine to form an osazone, m.p. 200-205° ;
with urea, accompanied by loss of water (C. 1905, I. 1084). Urochloralic Acid,
C7HUC13O7, m.p. 142°, decomposes with water absorption on boiling with dilute
hydrochloric or sulphuric acid into glucurcnic acid and trichlorethyl alcohol
(p. 117). Urobulyl Chloralic Acid, C10H16C13O7, decomposes, like the preceding
body, into glucuronic acid and aa/3-trichlorobutyl alcohol (p. 118).
Aldehydogalactmic Acid, COH[CHOH]5CO2H, is obtained from d-galactose
carboxylic acid, and may be converted into carboxygalac tonic acid (p. 655;.
7. Monoketotetrahydroxy Carboxylic Acids. Hydroxyglucuronic Acid, HOCH,.-
CO[CHOH]3CO2H, is formed, together with d-arabinose, when calcium gluconate
is oxidized ; also by bacterial action (B. 32, 2269), as in the case of the n.-hexitols
(P- 641).
8. POLYHYDROXYDICARBOXYLIC ACIDS
A. TETRAHYDROXYDICARBOXYLIC ACIDS
These are obtained by the oxidation of various carbohydrates with
nitric acid, and are readily prepared from the corresponding mono-
carboxylic acids upon oxidation with nitric acid. Mannosaccharic
acid, the saccharic acids, and the mucic acids are the most important
representatives of the series. Gluconic acid (p. 649) yields saccharic
acid, galactonic acid (p. 650), mucic acid, and mannonic acid (p. 648)
mannosaccharic acid. Their lactones, by very careful reduction, can
TETRAHYDROXYDICARBOXYLIC ACIDS 653
be converted into aldchydehydroxycarboxylic acids and hydroxy-
monocarboxylic acids. When reduced by HI and phosphorus the
preceding acids are converted into normal adipic acid (p. 505), hence
all of them must be considered as normal space-isomeric tetrahydroxy-
adipic acids. Theoretically, ten simple and four double modifications
are possible, as in the case of the n.-hexitols (p. 641). All the tetra-
hydroxyadipic acids, when heated with hydrochloric or hydrobromic
acid, change more or less readily to dehydromucic acid (B. 24, 2140)
(1) Mannosaccharic Acid, " CO2H[CHOH]4CO2H, is known in
three modifications (space-formula, p. 641), which pass into double
lactones when they are liberated from their salts. They also result
upon oxidizing the three mannonic acids with nitric acid (p. 648).
[d+l]-Mannosaccharolactone, C6H6O6, m.p. 190° with decomposition, is formed
by the union of d- and 1-mannosaccharolactcne ; and also from [d +l]-manno-
lactone ; diamide, m.p. 184° ; dihydr oxide, m.p. 220-225° (B. 24, 545).
d-Mannosaccharolactone, C6H6O6+2H2O, m.p. 181° anhydrous, is produced
when d-mannitol, d-mannose, and d-mannonic acid are oxidized with nitric
acid; diamide, m.p. 189°; dihydr azide, m.p. 212° (B. 24, 544). l-Manno-
saccharolactone, Metasaccharic Acid, C6H 6O6-f 2H2O, m.p. 68°, anhydrous, 180°,
is produced when 1-mannonic acid and the lactone of 1-arabinose carboxylic acid
are oxidized (B. 20, 341, 2713) ; diamide, m.p. 190° ; dihydrazide, m.'p. 213°.
Diactyl l-Mannosaccharolactone, m.p. 155° (B. 21, 1422 ; 22, 525 ; 24, 541).
(2) d- and 1-Idosaccharic Acids are syrups. They are obtained
by oxidizing the corresponding idonic acid (p. 650) (space-formula,
p. 642).
(3) Saccharic Acid, CO2H[CHOH]4CO2H, exists in three modifi-
cations (space-formulae, p. 642) ; of these the d-saccharic acid is
ordinary saccharic acid.
[d+Y]-Saccharic Acid is formed by the oxidation of [d+l]-glu conic acid. Its
monopotassium salt is formed on mixing solutions of equal quantities of the
d- and 1-salt ; dihydrazide, m.p. 210° (B. 23, 2622).
Ordinary, ond-saccharic acid, results in the oxidation of sucrose
(B. 21, R. 472), d-dextrose (grape sugar), d-gluconic acid and d-gluconic
lactone (B. 24, 521), and many carbohydrates with nitric acid ; also
from the action of bromine water on glucuronic acid (p. 652).
If forms a deliquescent mass, readily soluble in alcohol. If the
pure syrupy acid be allowed to stand for some time, it changes to a
crystalline lactonic acid, C6H8O7, m.p. 131°. It is converted into
glucuronic acid when reduced with sodium amalgam. Hydriodic acid
reduces it to adipic acid. When oxidized with nitric acid, d-tartaric
acid (B. 27, 396) and oxalic acid are formed
Sails. — The hydrogen potassium salt, C6H8O8K, anu the ammonium salt,
36H9O8(NH4), dissolve with difficulty in cold water ; diethyl ester is crystalline ;
imide is a white powder ; tetra-acetate, m.p. 61°. Acetyl chloride, acting on
1 free saccharic acid, converts it into the lactone of diacetyl saccharic acid,
• 36H4(O.C2H8O)2O4, m.p. 188°. Monomethylene Saccharic Acid (A. 292, 40).
; The diamide is a white powder; dihydrazide, m.p. 210° with decomposition
t [B. 21, R. 186).
l-Saccharic Acid is obtained upon oxidizing 1-gluconic acid with nitric acid. It
' s quite similar to d-saccharic acid, but is laevo-rotatory. It also forms a
) Uhydratide. m.p. 214°.
654 ORGANIC CHEMISTRY
.P. 210°
(4) Mucic Acid, Acidum mucicum, CO2H[CHOH]4CO2H, m.p.
with decomposition, corresponds in constitution with dulcitol, and
possesses the space-formula No. 7 (p. 642), one of the two theoretically
possible forms of tetrahydroxyadipic acid, optically inactive through
internal compensation. This is supported by its oxidation to racemic
acid, and its formation by oxidation from a-rhamnose carboxylic acid
(p. 650) (B. 27, 396).
It is also obtained in the oxidation of dulcitol, lactose (Preparation,
A. 227, 224), d- and 1-galactose, d- and 1-galactonic acid, and nearly
all the gum varieties.
It is a white crystalline powder, almost insoluble in cold water and
alcohol. When boiled for some time with water it passes into a readily
soluble lac tonic acid, CfiH8O7, formerly designated paramucic acid,
d-saccharolactonic acid (p. 653 ; B. 24, 2141). Reduction changes
this mucic lactonicacid into [d+l]-galactonic acid (p. 650 : B. 25, 1247).
Mucic acid heated to 140° with pyridine becomes allomucic acid, from
which it can be reformed under similar conditions.
The ready conversion of mucic acid into furfurane derivatives is
rather remarkable. Digestion with fuming hydrochloric or hydro-
bromic acid changes it to furfurane dicarboxylic acid (dehydromucic
acid) :
>CO,H
CH(OH)CH(OH)C02H CH=CX
- | >0 +3HaO.
CH(GH)CH(OH)CO2H CH=C\
XC02H
When mucic acid is heated alone it loses carbon dioxide and
becomes converted into furfurane monocarboxylic acid (pyromucic
acid) :
C4H4(OH)4(COaH)a - C4H,O.C01H+3HtO+C01.
Heated with barium sulphide it passes in like manner into a-thio-
phcne carboxylic acid (B. 18, 457).
Pyrrole is produced when the diammonium salt is heated :
C6H8(NH4)a08 =* C4H4NH+NH3-f2C02+4H20.
5a//s and Esters. — The di-potassium salt and di-ammonium salt, crystallize
well and dissolve with difficulty in cold water ; the hydrogen salts dissolve readily.
The silver salt, C8H8AgaO8, is an insoluble precipitate ; diethyl ester, m.p. 158° ;
tetr a- acetate, m.p. 177° (B. 21, R. 186 ; C. 1898, II. 963).
See p. 522 for the action of PC16 on mucic acid.
(5) Allomucic Acid, C8H10O8, m.p. 166-171°, is optically inactive, and
more soluble than mucic acid, from which it is obtained on heating with pyridine,
and into which it also passes (see mucic acid (B. 24, 2136).
(6) Talomucio Acid, COtH[CHOH]4COaH, is known in two space-isomeric
modifications :
d-Talomucic Acid, m.p. about 158° with decomposition, and resulting from
the oxidation of d-talonic acid (B. 24, 3625).
l-Talomucic Acid, prepared by oxidizing /J-rhamnose carboxylic acid (p. 650)
(6.27,384).
(7) Isosaceharic Aeid, COaH.CH.CHOH.CHOH.<iHC9aH, m.p. 185°. [0JD
•=+46'i° results from glucosamine (p. 636) upon oxidizing it with nitric
acid (B. 19, 1258 ; see also Chitonic and Chitaric Acids, p. 650). The acid itself
PENTAHYDROXY-DICARBOXYLIC ACIDS 655
and some of its derivatives must be regarded as compounds of tetrahydro-
furfurane, as is evident from the constitution formula of the acid. Other deriva-
tives should be referred to isosaccharic acid -j-HjO — that is, to tetrahydroxy •
adipic acid, and they are described as derivatives of norisosaccharic acid; for
example, the diethyl ester. C4H8O,(C2H6)2, m.p. 73°, which changes in the desiccator
to the Diethyl Ester of Isosaecharic Acid, CiHaO7(C1H,)1, m.p. 101°. Diacetyl
Isosaccharic Ester, m.p. 49° (B. 27, 118).
B. PENTAHYDROXYDICARBOXYLIC ACIDS
Pentahydroxypimelie Acid, [Glucoheptanepentol Diacid], CO2H[CHOH]5CO2H,
is produced in the oxidation of dextrose carboxylic acid with nitric acid ; lactone
is crystalline, m.p. 143° (B. 19, 1917).
a-Carboxygalactonie Acid, [a-Galaheptanepentol Diacid], CO2H[CHOH]6CO2H.
m.p. 171° with decomposition, is formed in the oxidation of a-d-galactose
carboxylic acid with nitric acid. It dissolves with difficulty in water, and
crystallizes in plates.
/?-Galaheptanepentol Diacid, is formed from 5-galaheptonic acid and nitric
acid (A. 288, 155).
9. Tetraketodicarboxylic Acids.
Acetonyl Acetone Dioxalic Ester, C8H6O2C.CO.CH2COCH2.CH2COCH2.CO.COa-
C2H5, m.p. 101°, is prepared from acetonyl acetone (p. 350), oxalic ester, and
sodium in ethereal solution. Hydrazine produces a dilactazam, ethane dipyrazyl
carboxylic ester (B. 33, 1220).
<Mv-Diacetyl $-Diketoadipic Acid, CH8CO.CH(CO2H)COCOCH(COCH8)CO2H,
is the hypothetical parent substance from which is derived Dicyano-bis-aceto-
acetic Ester, aa^Diacetyl ffi^Diiminoa-dipic Ester (i), m.p. 132°. This is prepared
from dicyanomonoacetoacetic ester (p. 608), acetoacetic ester, and a little sodium
alcoholate. Alkalis convert it first into a yellow lactam (t), m.p. 136°, and later
into the free acid, m.p. 230° with decomposition. Reduction with sodium
amalgam, accompanied by simultaneous ketone decomposition, forms a8-Diacetyl
fiy-Diaminovaleric Ester (3), m.p. 35° (A. 332, 138) :
CH°>C(NH)
CH,COCH,.HNH,
,.6
10. Triketotri carboxylic Acids.
a-Acetyl BfcDiketoadipic a^-Carboxylic Acid, CH3COCH(CO2H)COCOCH(CO2-
H)2, has, as a derivative, Dicyanacetoacetic Malonic Ester, CH8COCH(CO2C2H5) -
e(NH)C(NH)CH(.CO2C2H5)2,m.p. 93°, the reaction product of dicyanacetoacetic
ester (p. 608) and malonic ester (A. 332, 144). But dicyanomalonic ester and so-
dium acetoacetic ester yield Dicyanomalonic Acetoacetic Ester Lactam, m.p. 137°
(indefinite). Similarly, dicyanocyanacetic ester and sodium acetoacetic ester give
rise to Dicyanocyanacetic Acetoacetic Ester Lactam, m.p.i68°(indefinite) (A. 882/129).
Oxalyl Dimalonic Acid, fifi-Diketoadipic aa^Dicarboxylic Acid, (HO2C)2CH.CO.-
COCH(CO2H)2, is the hypothetical parent substance of dicyano-bis-malonic
acid, (HO2C)2CHC(NH).C(NH).CH(CO2H)2, of which the dilactam is formed from
dicyanogen and sodium malonic ester. Sodium amalgam reduces it to diamin-
adipic dicarboxylic acid, which losei CO, and becomes changed into /j^diamino-
adipicacid (p. 606) (A. 832, 122).
n. Hydro xyketotetracarboxylic Acids.
CO,R C02RC02R
Oxalocitric Lactone Ethyl Ester, CH - C - CH2, b.p.80 210°, is prepared
CO— COO
from two molecules of oxalacetic ester by aldol condensation and lactone forma-
tion (A. 295, 347)-
...
led
;tra-
acid
656 ORGANIC CHEMISTRY
12. Diketotetracarboxylie Acids.
R02C.CO.CH.C02R
Dioxalosuccinic Ethyl Ester, \ , is formed by the conden-
RO2C.COCH.CO2R
sation, of succinic and oxalic esters by sodium ethoxide. When distilled
under' greatly reduced pressure it loses CO and is converted into ethane tetra-
carboxvlic ester. When liberated from its disodium compound by sulphuric
O - CO
it gives Dioxalosuccinic Lactone Ethyl Ester, RO2C.C:C(CO2R).CH.CO.COaR, m.p.
89° (A. 285, ii).
13. Hexacarboxylic Acids.
Ethane Hexacarboxylic Acid, (CO2H)3C.C(CO2H),, is not known, though
derivatives exist, of which two may be mentioned.
Bis-cyanomalonic Ester, NC.C(Cp2C2H6)2.C(CO2C2H5)CN + i£H2O, m.p. 57°,
is obtained by electrolysis of sodium cyanomalonic ester (C. 1905, I. 1141).
Also, by the action of carbon disulphide and bromine on sodium malonic ester
and sodium cyanacetic ester there is formed Dithiotetrahydrothiophene Tetra-
(RO8C)2C.CSV
carboxylic Ester, \ >S, (B. 34, 1043).
(RO2C)2C.CS/
Pentane oayy '^-Hexacarboxylic Ester, (RO2C)2CH.CH2.C(CO2R)2CH2CH-
(CO2R)2, m.p. 54°, b.p.16 155°, is prepared by condensation of two molecules
of formaldehyde and three of malonic ester brought about by diethylamine.
Its disodium salt and bromine produce a pentamethylene derivative (C. 1900, I.
802). On an isomeric pentane hexacarboxylic ester, CH2[C(CO2R)2.CH2CO2R]2,
see C. 1902, II. 733.
Hexane 1,^,^^,^,-Hexacarboxylic Ester, C2H6O2CCH2CH2C(CO2C2H6)2C(CO2-
CaHB)aCHaCHa.CO2C2H6, is formed from disodium ethane tetracarboxylic
ester and two molecules of /J-iodopropionic ester. Hydrolysis and decomposition
produces diglutaric acid (C. 1903, I. 628).
Heptane Hexacarboxylic Acid. A derivative of this acid is Trimethylene
Dicyanosuccinic Ester :
m.p. 69°, b.p.7 215°, produced by the interaction of trimethylene bromide on
sodium cyanosuccinic ester (C. 1897, II. 520 ; 1899, I. 826).
Appendix. Higher polycarboxylic ethyl esters may be obtained from sodium
propane pentacarboxylic ester, chloromalonic ester, and chloropropane penta-
carboxylic ester, giving rise to Butane Heptacarboxylic Ester, C4H3(CO2C2H5)7,
b.p.1M 280-285°, and Hexane Dekacarboxylic Ester, C6H4(CO2CaH5),0, a yellow
oil. Octane Tesserakaideka-carboxylic Ester, C8H4(CO2C2H6)14, is prepared from
sodium butane heptacarboxylic ester and chlorobutane heptacarboxylic ester.
It is the highest known carboxylic ester, and consists of a thick oil (B. 21, 2111).
CARBOHYDRATES *
This term is applied to a large class of compounds, widely distributed
in nature, comprising natural sugars, and substances related to them.
They contain six, or a multiple of six carbon atoms. The ratio of
their hydrogen and oxygen atoms is the same as that of these elements
in water, hence their name.
Most of the carbohydrates have their origin in plants, although
some are probably also produced in the animal organism. Those
* " Kohlenhydrate," von B. Tollens. " Die Chemie dei Zuckerarten," von
E. O. von Lippmann, II. Auflage, 1895. " Die Chemie der Kohlenhydrate und
ihre Bedeutung fiir die Physiologic," von E. Fischer, 1894.
DISACCHARIDES, SACCHAROBIOSES 657
which occur in the vegetable kingdom meet with the most extensive
employment.
Carbohydrates serve for the preparation of alcoholic drinks (p. 114).
Sugars, particularly cane sugar, form the basis of many foodstuffs.
Starch is the chief ingredient of flour from which bread, the most
important food, is made. It is found stored up in potatoes and grain
fruits. Cellulose, related to it, is the principal constituent of wood,
cotton, etc., and is applied in paper-making and for the production
of explosives. The carbohydrates in conjunction with the proteins
constitute the most important food-materials for man.
Their molecular magnitude is the basis of their arrangement into
these classes :
Monoses, or Monosaccharides,
Saccharobioses, or Disaccharides,
Saccharotrioses, or Trisaccharidts,
Poly saccharifies.
The monosaccharides, including dextrose and laevulose, have
already been discussed in connection with the hexahydric alcohols,
of which they are the first oxidation products (p. 626).
Nearly all of the naturally occurring carbohydrates are optically
active, i.e., their solutions rotate the plane of polarization of light (p. 54).
The specific rotatory power is not only influenced by the temperature
and concentration of their solutions, but very frequently also by the
presence of inactive substances (B. 21, 2588, 2599). Some represen-
tatives also exhibit the phenomena of birotation and semirotation
(p. 632). Constant rotation is generally attained by heating the
solutions for a brief period. The determination of this rotatory
power of the carbohydrates by means of the saccharimeter serves to
ascertain their purity, or for the determination of their amount when
dissolved : optical sugar test, saccharimetry (p. 659).
A. DISACCHARIDES, SACCHAROBIOSES
Disaccharides, consisting of two molecules of dextroses or monoses
(p. 625), hence termed biases t have up to the present only been known
among the hexoses, C6H12O6 (see Galacto-arabinose (p. 660), their
formula being C12H22On. By the absorption of water they are
resolved into two molecules of the hexoses :
2C,HltO..
nMu. .
This reaction is known as hydrolytic decomposition or hydrolysis.
The higher carbohydrates are also capable of undergoing this change.
The constitution of the disaccharides indicates that they are ether-
like anhydrides of the hexoses, in which the union occurs either through
the alcohol and the aldehydo- or keto-group. Lactose and maltose
also contain the aldose group, CH(OH).CHO, as is shown by their
reducing Fehling's solution upon boiling, forming osazones with phenyl-
hydrazine, and when oxidized with bromine water, yielding monobasic
acids, C12H22O12, lacto- and maltobionic acids (p. 660) (B. 21, 2633 ;
22, 361). Sucrose does not show reducing power and does not yield
VOL. l, 3 V
658 ORGANIC CHEMISTRY
an osazone ; the reducing groups of dextrose and laevulose appear to
be combined together in this compound. The osazones of some of
these sugars split off glyoxal osazone when treated with alkalis (B.
29, R. 991) (comp. also the formation of glyoxalin from the hexoses
and ammonia, p. 630).
The hydrolysis of the saccharobioses has already been described in
detail under alcoholic fermentation (p. 112) ; it is brought about by
unorganized ferments, such as diastase and synaptase or emulsin (con-
tained in sweet and bitter almonds). Invertin (changing a dextro-
rotatory sugar solution into laevo-rotatory invert sugar), ptyalin (the
ferment of saliva), pancreas diastase, and other animal secretions exert
a like action (p. 677).
When the di- and poly-saccharides are heated with water and a
little acid they undergo hydrolysis, with a rapidity which, according to
Ostwald, bears a close relation to the affinity of the acids (J. pr.
Chem. [2] 31, 307). Certain inorganic salts, and also glycerol, are
capable of inverting sucrose (B. 29, R. 950 ; 27, R. 574).
Prolonged or strong heating with acid brings about a reversion, in which the
dextroses, and particularly Isevulose, undergo a backward condensation to dextrin-
like substances (B. 23, 2094). Also ferments such as maltase, kefir-lactase, etc., can
cause reversion of the hexoses into disaccharides. It is also possible to build up
some of the disaccharides from acetochlorodextrose (p. 634) or acetochloro-
galactose (p. 635) with sodium dextrose or sodium galactose in alcohol solution.
From this the galaclosidodextrose appears to be identical with melibiose (B. 35,
3M4)-
Sucrose, Saccharose, Saccharobiose, C12H22O1:i, m.p. 160°, D=r6o6,
[a]^ = 4-66'5° (B. 17, 1757), the most important of the sugars,
occurs in the juice of many plants, chiefly in sugar cane (Saccharum
officinarum) (20 per cent, of the juice), in some varieties of maple, in the
sorghum (Sorghum saccharatum), and in beet-roots (Beta maritima)
(10-20 per cent.), from which it is prepared on a commercial scale ;
and also in the seeds of some plants (B. 27, 62).
Whilst the hexoses occur mainly in fruits, sucrose is usually
contained in the stalks of plants. The sugar cane contains, together
with the sucrose, laevulose and dextrose, of which the quantity
diminishes with the growth of the plant.
Historical. — Sugar has been obtained from sugar cane from the earliest times.
In the middle ages sugar cane was a rarity in Germany ; it was only after the
discovery of America that it was gradually introduced as a sweetening agent.
In 1747 Marggraf,* in Berlin, discovered sucrose in beet- roots, an observation
which became the basis of the beet-sugar industry. In 1801 A chard, in Silesia,
erected the first beet-sugar factory. The continental blockade forced by
Napoleon I. hastened the development of the new industry, which during the last
fifty years has attained a constantly increasing importance in Germany, where
about one-fifth of the total sugar yield of the world is produced. In the year 1906-7,
369 factories consumed 14, 186,536 tons (i ton = 1000 kilos) of beets, which produced
2,242,000 tons of beet-sugar. The total production of sugar in the world was, in
1906-7, about 7,120,000 tons of beet-sugar and 5,140,000 tons of cane sugar.
Technical Preparation.^ — The sugar is best removed from the cane and from
* Ein Jahrhundert chemischer Forschung unter dem Schirme der Hohenzollern,
von A. W. Hofmann, 1881.
t Hdb. d. chem. Technologic, Ferd. Fischer, 1893. s- 851-888.
DISACCHARIDES, SACCHAROBIOSES
659
the finely divided beets by the diffusion process. The saccharine juice diffuses
through the cell walls, whereas the colloids in the latter remain behind. The
filtered sap is heated to 80-90° with milk of lime, to saturate the acids, and pre-
cipitate the prot-ins. The juice is next treated with carbon dioxide, phosphoric
acid, or SO2 (to arrest fermentation), filtered through animal charcoal,
and is concentrated in vacuum pans till it crystallises. The mother-liquor,
tnelasse, is separated by centrifugation, and the solid is washed with a pure
sugar solution (" Klarsel ") or purified by recrystallisation, and thus forms refined
sugar.
Sugar may be obtained from the syrupy mother liquor — the molasses, which
cannot be brought to crystallization :
(1 ) By osmosis, depending upon diffusion through parchment paper, in appara-
tus similar to filter presses.
(2) By washing (Schcibler,. 1865). The sparingly soluble saccharates of
lime and strontium are obtained from the molasses (see below) and these are
freed from impurities by washing with water or dilute alcohol. The purified
saccharates are afterwards decomposed by carbon dioxide, and the juice which
is then obtained, after the above plan, is further worked up.
The molasses is also converted into rum (p. 114).
Properties. — When its solutions are evaporated slowly, sucrose
separates in large monoclinic prisms, and dissolves in one-third part
water of medium temperature ; it dissolves with difficulty in alcohol.
After being melted it solidifies to an amorphous glassy mass (sugar
candy), which in time again becomes crystalline and non-transparent.
At 190-200° it changes to a brown non-crystallizable mass, called
caramel, which finds application in colouring food stuffs.
The quantity of sugar in solution may be determined by polariza-
tion, using the apparatus of Soleil-Ventzke-Scheibler, or the half-shadow
instrument devised by Schmidt and Hansch (B. 27, 2282), as well as
from the specific gravity by means of the saccharimeter of Brix.
Reactions and Constitution. — Sucrose is hydrolyzed into d-dextrose
and d-lasvulose (invert sugar) when boiled with dilute acids ; and
also by the action of ferments. It is only after this occurs that it is
i capable of reducing Fehling's solution. Mixed with concentrated
sulphuric acid it is converted into a black, humus-like body. d-Sac-
charic acid, tartaric acid and oxalic acid are formed when it is boiled
with nitric acid. Sucrose heated to 160° with an excess of acetic
anhydride gives octacetyl ester, C12H1408(O.COCH3)8, m.p. 67° (B. 34,
4347). This latter fact and the failure of sucrose to reduce Fehling's
solution under ordinary conditions are made to appear in the following
formulae :
I. (Tollens)
(B. 16, 923)
CH.OH
CH.OH
II. (E. Fischer] /CH Ox
(B. 26, 2405) / |
/CHOH
\ CH.OH
VH
CHtOH
1
C
CH.OH
.OH
CHOH
CH,OH
\ CH.
\CH
CH,OH
Saccharates.— Sucrose unites with bases to form saccharates ClsHaiOn.CaO +
2HaO, is precipitated by alcohol, whilst C12H22On.2CaO crystallizes on cooling.
CtJH^O,, 3CaO dissolves with great difficulty (B. 16, 2764). Similar compounds
are formed with the oxides of strontium and barium (see above) (B. 10. 984)*
660 ORGANIC CHEMISTRY
Telranitrosaccharose, C12Hi8(NO2)4On, explodes violently.
Lactose, Milk Sugar, Lactobiose, C^H^On+HoO, m.p. anhydrous
205° with decomposition, occurs in the milk of mammals, in the amniotic
liquor of cows, and in certain pathological secretions. Fabriccio
Bartoletti, of Bologna, discovered it in 1615.
Lactose is prepared from whey, which is evaporated to the point of crystalliza-
tion, and the sugar which separates is purified by repeated crystallization.
Lactose crystallizes in white, hard, rhombic prisms, which become
anhydrous at 140°. It is soluble in 6 parts cold or 2\ parts hot water,
has a faint sweet taste, and is insoluble in alcohol. Its aqueous solution
is dextro-rotatory and exhibits birotation (p. 632). It resembles the
hexoses in reducing ammoniacal silver solutions in the cold, but in case
of alkaline copper solutions boiling is necessary.
Reactions and Constitution. — Lactose is decomposed into galactose and
d-dextrose by being heated with dilute acids. It is only slowly attacked by
yeast, but it readily undergoes lactic acid fermentation (pp. 363, 631). Nitric acid
converts it into d-saccharic and mucic acids. Bromine produces lactobionic acid,
CujHajOu, which splits up into d-gluconic acid and d-galactose ; whilst oxidation
with HjOj breaks it down, as it does the aldoses (p. 617) into galacto-arabinose,
CUH20O10. The latter forms an osazone, m.p. 237°, and is hydrolyzed into
d-galactose and d-arabinose (B. 33, 1802). Lactose takes up hydrocyanic acid
and forms ultimately lactose carboxylic acid, C^H^O^.CO^H., which decomposes
into d-glucoheptonic acid (p. 651) and d-galactose (A. 272, 198). See also
Isosaccharine (p. 620). Lar.tosa.znne. C12H20O9(N2HC8H6)2, m.p. 200° (B. 20,
829). Octo-acetyl Lactose, C/jh^OglpCOCHglg, m.p. 106°, yields, with fluid HC1
hepta-acetyl chlorolactose, C12H14O8OCOCH8)7C1. Hepta-acetyl Bromolactose is
formed from lactose and acetyl bromide. The two last-named lactose compounds
exhibit polymorphism. When treated with methyl alcohol and silver carbonate,
they yield hepta-acetyl methyl lactose, C12H14O3(OCOCH3)7CH3 (B. 35, 841;
C. 1902, II. 1416). These changes demonstrate the formula of lactose to be that
of galactodextrose :
HOCHa.CHOH.CH[CHOH]2CH— O— CH2[CHOH]4CHO.
Lactic acid forms a crystalline compound with aminoguanidine nitrate and
sulphate (B. 28, 2614).
Maltose, Malt Sugar, Maltobiose, C^H^O
(B. 28, R. 990 ; C. 1897, II. 695), is a variety of sugar formed, together
with dextrin, by the action of malt diastase (p. 115) on starch as in the
mash of whiskey and beer. It is also an intermediate product in the
action of dilute sulphuric acid on starch, and of ferments (p. 677)
diastase, saliva, pancreas on glycogen (p. 662). It can also be obtained
from starch paste by means of diastase (A. 220, 209). It is capable
of direct fermentation. It forms a hard, white, crystalline mass.
Reactions. — It was formerly believed that maltose could be directly fermented
by yeast. It appears, however, that there is present a second enzyme (glucase ?)
which, along with invertin, which does not hydrolyze maltose, decomposes
the maltose into dextrose (B. 29, R. 663). Maltose reduces Fehling's solution,
but only about two-thirds as much as dextrose, which it resembles very closely
(A. 220, 220).
Diastase does not exert any change on maltose. When boiled with dilute
acids, it absorbs water and passes completely into d-dextrose or grape sugar.
Nitric acid oxidizes it to d-saccharic acid, whilst chlorine changes it to malto-
This yields dextrose and d-gluconic acid when it is
POLYSACCHARIDES 661
heated with acids. Hydrocyanic acid transforms it into maltose carboxylic
acid, C12H23On.CO2H, which decomposes into d-dextrose and d-glucohep tonic
acid (A. 272, 200).
When boiled with lime-water it forms isosaccharine (p. 620). Octacetyl
Ma//os*,CiaH14O3(OCOCH3)8, m.p. 156°, yields, with fluid HC1 Heptacetyl Chloro-
maltose, C]2H14O3(OCOCH3)7C1, m.p. 67°; fuming nitric acid in chloroform
solution produces Heptacetyl Maltose Nitrate, Ci2H14O8(OCOCH3)7(ONOa), m.p.
94°. Both the latter substances react with methyl alcohol to form a Heptacetyl
Methyl Maltose, m.p 128°, from which the loss of the acetyl groups leaves fi-Methyl
Maltose, Ci2H21On(CH3), m.p. 94° (B. 34, 4343; 35, 840). Maltosazone, m.p.
206°, is decomposed by benzaldehyde into maltosone (B. 20, 831 ; 35, 3142).
Maltose is constituted similarly to lactose (p. 660) (B. 22, 1941).
The following saccharobioses are less important: Isomaltose, C12H22On,
[a]D=+7o°, isomeric with maltose, results from the action of hydrochloric acid
on d-dextrose (B. 28, 3024), and in the mashing process (B. 25, R. 577 ; B. 29,
R. 991). Yeast does not ferment it ; diastase converts it into maltose ; osazone,
m.p. 150-153°.
Mycose, Trehalose, C12H22On+2H2O (B. 24, R. 554; 28, 1332), occurs in
several species of fungi — e.g., in Boletus edulis (B. 27," R. 511), in ergot, and in the
oriental Trehala. Acids convert it into d-dextrose (B. 26, 3094).
Melibiose, CI2H22On, m.p. 84° (incomplete), [a] £°= + 129-38° (C. 1899, II.
526) is prepared from melitriose (see below) ; it is probably identical with the
synthetic galactodextrose (p. 658). It is decomposed by hydrolysis into
d-galactose and d-dextrose; osazone, m.p. 177° (B. 22, 3113; 23, 1438, 3066;
35,3146).
Turanose, C12H22OU, [a]D=+65 to +68°, is formed along with d-dextrose
in the partial hydrolysis of melecitose as a white mass ; osazone, m.p. 215-220° (B.
27, 2488).
Agavose, C12H22On, is obtained from the stalks of Agave americana (B. 26,
R. 189). Lupeose, C^H^O^ is contained in lupin seeds (B. 25, 2213).
B. TRISACCHARIDES, SACCHAROTRIOSES
Raffinose, Melilose, Melitriose, C18H32O16-f5H2O (B. 21, 1569,
C. 1897, II. 520) [a]D=i04°, occurs in rather large quantity in Australian
manna (varieties of Eucalyptus), in cotton seed meal, in small amounts
in sugar beets, and being more soluble than sucrose, it accumulates
in the molasses in sugar manufacture. From this it crystallizes
out with the sugar (A. 232, 173). Its crystals have peculiar terminal
points, and show strong rotatory power (Plus sugar).
To determine raffinose quantitative!)', consult B. 19, 2872, 3116.
By hydrolysis it yields fructose and melibiose (B. 22, 1678 ; 23, R. 103).
Melecitose, C18H82O1$-f2H2O, m.p. (anhydrous) 148°, occurs in the juice
of Pinus larix, and in Persian manna. It is distinguished from sucrose by its
greater rotatory power (B. 26, R. 694), and in not being so sweet to the taste.
It decomposes by partial hydrolysis into d-dextrose and turanose (B. 27, 2488).
Stachyose, ClgH,aO18, is obtained from Stachys tuberifera (B. 24, 2705).
C. POLYSACCHARIDES
The polysaccharides having the empirical formula C6H10O5, all
possess a much higher molecular weight, (C6H10O6);l, and differ much
more from the hexoses than the di- and tri-saccharides. They are,
in general, amorphous and soluble in water, except cellulose, which is
insoluble. By hydrolysis, by boiling with dilute acids, or under the
influence of ferments (p. 677), nearly all are finally broken up into
loses (see Dextrin). Their alcoholic nature is shown in their ability
662 ORGANIC CHEMISTRY
to form acetyl and nitric esters. They may be classified as starches,
gums and cellulose.
There are certain gums, like cherry gum and wood gum (p. 663) which yield
pentoses by hydrolysis. They are, therefore, called pentosans to distinguish
them from the dextrosans — the polysaccharides, which break down into dextroses
when they are hydrolyzed (B. 27, 2722).
On experiments for determining the molecular magnitude of the polysaccharides
such as starch, glycogen, cellulose, by chemical and physical means, see C. 1906,
I. 655, etc.
Starches.— (i) Starch, Amylum, (C6H10O5)n, is found in the cells
of many plants, in the form of circular or elongated microscopic granules,
having a definite structure. The size of the granules varies, in different
plants, from O'oo2-O'i85 mm. Air-dried starch contains 10-20 per
cent, of water ; dried over sulphuric acid it retains some water, which is
only removed at 100°. .Starch granules are insoluble in cold water
and alcohol. When heated with water they swell up at 50°, burst,
partially dissolve, and form starch paste, which rotates the plane of
polarization to the right. The soluble portion is called granulose, the
insoluble, starch cellulose. Alcohol precipitates a white powder — soluble
starch — from the aqueous solution (C. 1897, II. 842).
One of the supposed main differences between granulose and
cellulose in the starch grains appears on closer examination not to
exist, since starch is completely soluble at 138° ; the starch cellulose
is perhaps a reversion product (see p. 658) of the partially hydrolyzed
starch. The main constituent of starch, that which is coloured by
iodine, and is completely converted by malt into maltose (see below),
is known as amylose, which is different from the slimy, paste-forming
constituent known as amylopectin (see Pectin, p. 663) (A. 309, 288 ;
C. 1905, II. 314 ; 1906, II. 229).
The blue coloration produced by iodine is characteristic of starch,
both the soluble variety and that contained in the granules (B. 25,
1237 ; 27, R. 602 ; 28, 385, 783 ; C. 1897, 1. 408, 804 ; 1902, II. 26).
Heat discharges the coloration, but it reappears on cooling. Consult
B. 28, R. 1025, for a quantitative, colorimetric method for the deter-
mination of starch.
Boiling dilute acids convert starch into dextrin and d-dextrose
(Kirchhoff, 1811). When heated at 160-200° it changes into dextrin.
Malt diastase changes it to dextrin, maltose, and isomaltose (p. 661)
(B. 27, 293). This is a reaction which is carried out technically on
a large scale in the manufacture of alcohol from starch (p. 115).
(2) Paramylum, (C6H10O5)«, occurs in the infusoria Euglena viridis. It is not
coloured by iodine, and is soluble in potassium hydroxide.
(3) Lichenin. Moss-starch, (C,H10O,)n, occurs in many lichens, and in Iceland
moss (Cetraria islandica). Iodine imparts a dirty blue colour to it. It yields
d-dextrose when boiled with dilute acids.
(4) Inulin is found in the roots of dahlia, in chicory, and in many Compositae
like Inula helenium. Iodine gives it a yellow colour. When boiled with water
it is completely changed to d-fructose.
(5) Carubin, (C.HltO.)n, occurs in St. John's Bread, the pods of Ceratonia
sihqua, and is decomposed by mineral acids into d-mannose, C6H18O6.
(6) Glycogen, Liver Starch, (C6H10O5)n, is an important product
of metabolism, and occurs in the liver and other portions of mammals ;
POLYSACCHARIDES 663
also in the lower animals and fungi (mushrooms). The liver forms
glycogen from dextrose and other monoses, glycerol, formaldehyde
etc. (C. 1907, II. 168; 1908, I. 1176). When boiled with dilute acids
glycogen is changed into d-dextrose; ferments, however, produce
maltose. For quantitative determination see C. 1899, I. 572 * 1903
I. 1305-
The Gums. — These are amorphous, transparent substances widely
disseminated in plants ; they form sticky masses with water and are
precipitated by alcohol. They are odourless and tasteless. Some of
them yield clear solutions with water, whilst others swell up in that
menstruum and will not filter through paper. The first are called the
real gums and the second vegetable mucilages. Nitric acid oxidizes
them to mucic and oxalic acids.
Dextrin, Starch Gum, Leiocome, (C6H10O5)n. — By this name are
understood substances readily soluble in water and precipitated by
alcohol ; they appear as intermediate products in the conversion of
starch into dextrin, e.g., heating starch alone at 170-240°, or by
heating it with dilute sulphuric acid. Different modifications arise
in this treatment : amylodextrin, erythrodextrin, achroo -dextrin, which,
however, have received little study (B. 28, R. 987 ; 29, R. 41 ; C.
1897, I. 408 ; A. 309, 288). They are gummy, amorphous masses, of
which aqueous solutions are dextro-rotatory, hence the name dextrin.
They do not reduce Fehling's solution, even on boiling, and are incapable
of direct fermentation ; in the presence of diastase, however, they can
be fermented by yeast (p. 113), and are then converted into d-dextrose.
They yield the same product when boiled with dilute acids. The
dextrins unite with phenylhydrazine (B. 26, 2933). The yeast gum
present in yeast cells, has been isolated (B. 27, 925).
Dextrin is prepared commercially by moistening starch with two per cent.
nitric acid, allowing it to dry in the air, and then heating it to 1 10°. It is employed
as a substitute for gum (B. 23, 2104).
Arabin, Gum, exudes from many plants, and solidifies to a transparent, glassy,
amorphous mass, which dissolves in water to a clear solution. Gum arabic or
gum S enegal consists of the potassium and calcium salts of arabic acid . The latter
can be obtained pure by adding hydrochloric acid and alcohol to the solution. It
is then precipitated as a white, amorphous mass, which becomes glassy at 100°,
and possesses the composition (C,H10O6)t+HaO. It forms compounds with
nearly all the bases, which dissolve readily in water.
Some varieties of gum, e.g., gum arabic, yield galactose in considerable quantity
when boiled with dilute sulphuric acid ; and with nitric acid they are converted
into mucic acid ; others, like cherry gum, are transformed on boiling with sulphuric
acid into 1-arabinose, C,H,0O, (p. 619), and into oxalic acid, not mucic acid, by
nitric acid. The gum, extracted from beechwood by alkalis and precipitation
with acids, is converted into xylose (p. 619) by hydrolytic decomposition. Hence
these gums must be regarded as pentosans (p. 662) (B. 27, 2722). On the
hydrolysis of the pentosans, see also B. 36, 319)'
Bassorin, Mucilage, constitutes the chief ingredient of gum tragacantb,
Bassora gum, and of cherry and plum gums (which last alsO contain arabm).
swells up in water, forming a mucilaginous liquid, which cannot be filtered ; it
dissolves very readily in alkalis. On the hydrolysis of plant-mucus, see B. 80,
19 Pectin substances (from miierts, coagulated) occur in fruit juices, e.g. .apple,
cherries, currants, greengages, etc. They cause these, under suitable condU
to gelatinize. They are closely allied to the vegetable gums, and may be regarded
as oxymucilage (A. 286, 278 ; B. 28, 2609).
664 ORGANIC CHEMISTRY
Cellulose, Wood Fibre, Lignose (ClzH2(f>io}x, possibly C72H12006o
(B. 32, 2507), forms the principal ingredient of the cell membranes
of all plants, and exhibits an organized structure. To obtain it pure,
plant fibre, or, better, cotton-wool is treated successively with dilute
potassium hydroxide solution, dilute hydrochloric acid, water, alcohol,
and ether, to remove all admixtures (incrusting substances). Cellulose
remains then as a white, amorphous mass.
Sulphite Cellulose is prepared by treating wood with hot calcium
bisulphite liquor under pressure, whereby the lignin surrounding the
wood fibre is dissolved. Sodium cellulose is formed when straw is
heated with sodium hydroxide solution. Cellulose is employed for the
manufacture of paper, parchment paper, gun-cotton, smokeless pow-
der, celluloid and celluloid-like bodies, artificial silk, oxalic acid, etc.
Cellulose is insoluble in most of the usual solvents, but dissolves
without change in an ammoniacal copper solution (B. 38, 2798). Acids,
various salts of the alkalis and sugar precipitate it as a gelatinous
mass from such a solution. After washing with alcohol it is a white,
amorphous powder. When acted on by sodium hydroxide solution
of various concentrations, cellulose absorbs the alkali with simul-
taneous contraction. The alkali can be removed by washing with
water leaving the cellulose behind as a hydrate (Mercerisation, B. 40,
441, 4903). The alkali cellulose combines with carbon disulphide to
form water soluble xanthates, known as viscose (B. 34, 1513, etc.),
which on hydrolysis also yield hydrocellulose or cellulose hydrates.
These hydration products of cellulose can also be produced in various
other ways.
Oxycelluloses constitute a whole series of bodies obtained when
cellulose is oxidized by nitric acid, bleaching powder, permanganate,
and hydrogen peroxide (B. 34, 719, 1427, 2415, 3589).
If unsized filter paper be immersed for a short time in sulphuric
acid, which has been diluted with half its volume of water, and then
washed with water there is formed parchment paper (vegetable parch-
ment) which is similar to parchment, and has many uses. In concen-
trated sulphuric acid cellulose swells and dissolves to a paste from which
water precipitates a body similar to starch (amyloid), which is coloured
blue by iodine. Prolonged action of sulphuric acid produces dextrin,
which is converted into racemic acid by dilution and subsequent
boiling. Sulphuric acid and acetic anhydride produce an acetoacetate
of a saccharobiose, the crystalline celloUose, C^H^On, osazone, m.p.
198°. This, which can be obtained from the acetate by hydrolysis
with potassium hydroxide, yields in part on hydrolysis with dilute
sulphuric acid, dextrose. Cellobiose stands in the same relation to
cellulose as maltose to starch (B. 34, 1115 ; C. 1902, I. 183 ; comp.
I. 1902, I. 405).
Nitrocelluloses. — Strong nitric acid produces from cellulose, first,
a hydrolyzable nitrate (B. 37, 349 ; C. 1908, I. 2024). A more concen-
trated acid, or, better, a mixture of nitric and sulphuric acids forms
nitric esters, known as nitrocelluse (C. 1901, II. 34, 92 ; B. 34, 2496).
According to the mode of action, the products show varying characteristics.
If pure cotton wool is immersed for 3-10 minutes in a cold mixture of I part of
ANIMAL SUBSTANCES OF UNKNOWN CONSTITUTION 665
nitric acid with 2-3 sulphuric acid, and then carefully washed with water, there
is formed gun-cotton (pyroxylin), which was discovered in 1845 by Schbnbein. It
is insoluble in alcohol and ether and their mixture, and explodes violently when
ignited in a closed space by percussion. In the air it burns very rapidly without
exploding. If the cotton wool be immersed for a longer time in a warm mixture
of 20 parts of powdered sodium nitrate and 30 of concentrated sulphuric acid,
there is formed soluble pyroxylin, which is dissolved by a mixture of ether and
a little alcohol. The solution is known as collodion ; this, on evaporation, leaves
the pyroxylin in the form of a thin transparent skin insoluble in water, which is
employed in surgery and photography.
The explosive insoluble gun-cotton consists mainly of cellulose
hexanitrate, C12H14(O.N02)6O4, whilst the ether-alcohol soluble pyro-
xylin is formed chiefly of the tetranitrate, C12H16(ONO2)4O6, and the
pentanitrate, C12H15(O.NO2)5O5 (B. 13, 186). The solution of collodion
cotton in nitrogylcerine (with small quantities of other substances),
constitutes a blasting gelatin which is employed as smokeless powder
(B. 27, R. 337).
When mixed with camphor, nitrocellulose forms celluloid, a sub-
stance like vulcanite (highly vulcanized rubber), having the dis-
advantage of burning violently when ignited.
Acetyl Cellulose is formed by the action of glacial acetic acid, acetic
anhydride, and a small quantity of concentrated sulphuric acid, or
zinc chloride on cellulose. It is characterized by its solubility in various
organic solvents and insolubility in water. It is used, like ammonium-
copper hydroxide cellulose (p. 664) and nitrocellulose, for the prepara-
tion of artificial silk, and many other technical purposes (C. iy02, 11.
1022 ; 1907, I. 1736 ; 1908, I. 1831).
Simultaneous action of acetic anhydride and nitric acid produces
cellulose acetonitrate (B. 41, 1837). Formic acid and sulphuric or
hydrochloric acid give rise to cellulose formate (C. 1908, I. 328).
Benzoyl chloride and pyridine produce benzoyl cellulose (C. 1903, I.
744)'
It is remarkable that it has been found impossible to introduce
more than three acyl, NO2, CH3CO, etc., groups into cellulose, of which
the simplest formula is C6H10O5 (C. 1906, II. 672). This, together
with the ease with which cellulose is converted by HC1 or HBr into
bromo- and chloro-methyl furfural (Vol. II.) suggests as the simplest
HO OH OH OH— —OH
formula >o >o L (C. 1906, II. 321), of which 12 polymers
HOCH— CH— CH2
of cellulose become possible.
The products of dry distillation of wood, such as acetic acid, acetone,
and methyl alcohol, are the most important decomposition-products of
cellulose. When fused with alkali, cellulose similarly yields oxalic acid
(p. 480). Fermentation of cellulose causes the formation of CO2,
hydrogen and methane (C. 1904, 1. 1338 ; I9°6» L I034. etc.).
ANIMAL SUBSTANCES OF UNKNOWN CONSTITUTION
Now that the description of the aliphatic bodies has been con-
1, certain substances of animal origin will be mentioned, of which
666 ORGANIC CHEMISTRY
exhaustive treatment properly belongs to the province of physiological
chemistry. It is especially noteworthy that very frequently well-
known mono- and di-amino-acids and hydroxyamino-acids of the
aliphatic series are found among the decomposition products of these
bodies. Many of the substances described in the following pages occur,
both in the vegetable and animal kingdoms, in closely related modi-
fications of uncertain constitution, e.g., the proteins, the nucle'ins, the
cholesterols, the enzymes, etc., and also the carbohydrates (p. 656) and
lecithins (p. 531), which have already received mention.
PROTEINS, ALBUMINS*
These were formerly known as proteid substances, and form the
principal constituents of the animal organism. They also occur in
plants (chiefly in the seeds), in which they are exclusively produced.
When absorbed into the animal organism as nutritive matter they
undergo but very slight alteration in the process of assimilation.
The composition of the different proteins varies within definite limits (J. pr.
Ch. [2] 44, 345) :
C 50-0 to 55-0 per cent. Crystallized Albumin : C 51-48 per cent.
H 6-9 „ 7-3 ,. H 676
N 15-0 „ 19-0 „ N 18-14
O 19-0 „ 24-0 M O 22-66 „
S 0-3 „ 2-4 „ S 0-96 „
The molecular magnitude of the proteins is not definitely known. There is
no doubt but that their molecular weights are large. Sabanejeff, employing
Raoult's method, obtained 15,000 for the molecular value of purified egg albumin.
All proteins rotate the plane of polarization to the left. They always leave an
inorganic residue when they are burned. In the solution and precipitation pro-
cesses employed in obtaining them free from mineral ash, the protein frequently
undergoes a change in its properties (B. 25, 204).
When the proteins are oxidized, there are formed volatile fatty acids and their
aldehydes, ketones and nitriles, hydrocyanic and benzoic acids. Permanganate
produces first oxyprotosulphonic acid, of the composition C=5i'2i per cent.,
H =6-89 per cent., N =14-59 percent., 8 = 1-77 percent., 0=25-54 per cent.; and
finally peroxyproteic acid 0=46-22 per cent., and H=6'43 per cent., N = I2'3O
per cent., 8=0-96 per cent., 0=34-09 per cent. (Z. physiol. Ch. 19, 225).
Boiling with dilute sulphuric or hydrochloric acid, or with barium hydroxide
solution or other alkalis, produces mainly amino-acids, the simplest decomposition
products of the proteins, with varying quantities of ammonia and carbon dioxide.
The most important of the acids, of which the structural formulae can be ascer-
tained are :
a. Monamino-monocarboxylic Acids.
Glycocoll, NHaCHaCOaH (p. 385). Hippuric Acid, Ce
(Vol. II.).
* Die Eiweissarten der Getreidearten, Hulsenfriichte und Oelsamen, von
H. Ritthauscn, 1872. Handbuch der physiologisch- und pathologisch-chemischen
Analyse, von F. Hoppe-Seiler, 1893. "Eiweisskorper," Artikel von Drechsel in
Ladenburg's Handw., 1885. R. Ngumeister, Lehrbuch der physiol. Chemie,
Aufl. II., 1897. Hammarsten, Lehrbuch der physiol. Chemie, Aufl. IV., 1899.
A. Kossel, Uber den gegenwartigen Stand der Eiweisschemie, B. 34, 3214; E.
Fischer, Untersuchungen liber Aminosauren, Polypeptide und Proteine, 1906.
PROTEINS, ALBUMINS 667
Alanine, NH2CH(CH3)CO2H (p. 388).
V aline. NHaCH[CH(CH,} JCO,H (p. 389).
Leucine, NH2CH[CH2CH(CH8)2]COaH (p. 389).
Isoleucine, NH2CH[CH(CH3)(CaH6)]COaH (p. 390).
Phenyl Alanine, NHaCH(CH2C6H6)CO2H (Vol. II.).
Tyrosine, NHaCH[CH,[i]C.H4[4](OH)]CO2H (Vol. II.).
Tryptophane, NHaCH[CHa.C<£«^*>NH]CO2H (Vol. II.).
b. Monamino-dicarboxylic Acids.
Aspartic Acid, NHaCH(CO2H)CH2CO2H (p. 553).
Glutaminic Add, NHaCH(CO2H)CHaCH2CO2H (p. 558).
c. Hydroxamino-, Thioamlno-, Diamino-, Imino-Acids.
Serine, HOCH2.CH(NH2)CO2H (p. 540).
Cystine, NH2CH(CO2H)CH2S.SCHaCH(NH2)CO3H.
Ornithine, NH2CH2CH2CH2CH(NH2)CO2H, together with Arginine, NH2C(NH)-
NH.CH2CH2CH2CH(NH2)CO2H, and Ornithuric Acid, C6H5CONHCH2CHaCHa-
CH(NHa)C02H (p. 542).
Lysine, NH2CH2CH2CH2CH2CH(NH2)COaH (p. 542).
Proline, NHCHaCH2CH8CHCOaH (p. 542).
Hydroxyproline, NHCHaCHaCH(OH)CHCO2H (?) (p. 598).
/NH.CH
Histidine, CB.^ \\ (comp. p. 546).
^N— C— CHaCH(NH2)CO2H
All these products are not obtained fiom ail proteins, and their relative
quantities vary within wide limits according to the various parent proteins. The
quantitative separation of each amino-acid from a mixture of decomposition
products has until now only been effected imperfectly, either by precipitation
methods (comp. p. 669) or by E. Fischer's method of esterifying the acid
mixture, and separating the esters by fractional distillation in vacuo (p. 49).
The hydrolytic decomposition of proteins is carried out most quickly by
mineral acids, and less well by alkalis ; further, the same effect is achieved by
means of the ferments of the alimentary canal such as pepsin and trypsin, whereby
the protein passes through a series of intermediate products — albumoses, peptones,
poly- and di-peptides (comp. pp. 390, 670) before the amino-acids are reached.
The mineral acid hydrolysis can be carried out so that the poly- and di-peptides
can be collected (B. 40, 3544).
The life processes of lower organisms such as the bacilli, bacteria, etc., con-
cerned in putrefaction break down the proteins into fatty acids up to caproic
acid, 8-aminovaleric acid (p. 389) (B. 24, 1364); phenyl acetic acid, C6H6CH2CO2H
(Vol. II.) ; p-hydroxyphenyl propionic acid, HO[4]C.H4[i]CHaCHaCOaH (Vol. II.) ;
phenol, C,H6OH (Vol. II.) ; also fi-indole propionic acid, indole acetic acid,
skatole (/2-methyl indole), indole — bodies which are produced by the breaking
down of tryptophane (see above) similarly to the previously mentioned from
phenyl alanine and tyrosine (formula, see above, and B. 37, 1801 ; 40, 3029).
Other basic substances are also formed during putrescence, mainly diamines and
imines of the fatty series, known as ptomaines and toxins (p. 331).
Certain pathogenic organisms, such as the diphtheria and anthrax bacilli,
produce a less far-reaching basic decomposition (?) whereby poisonous protein
and peptone-like bodies are formed known as toxalbumins, which, when heated
in aqueous solution lose their poisonous properties (B. 23, R. 251).
Proteins are produced in plants in daylight by unknown means from CO2,
H2O, NHS, HNO, and HaSO4 ; plants containing chlorophyll also use substances
containing the groups — CH2 — and — CHOH — .
A knowledge of the constitution of the proteins can only be formed from a
few general aspects.
The decomposition products show that the major part of the carbon is aliphatic.
Also the protein yields only a relatively small quantity of break-down products
possessing the aromatic ring, such as phenyl alanine, tyrosine, tryptophane, as
well as phenol, skatole and indole (B. 12, 652, 1987).
Potassium or barium hydroxide solution expels various quantities of N as NH,
668 ORGANIC CHEMISTRY
(up to J) according to the kind of protein, and length of time of boiling (C. 1867,
385; Pfliiger's Arch. 6, 606 ; Z. physiol, Chem. Ch. 29, 51).
When boiled with hydrochloric acid, about tV of the N separates as NH3,
$ to | as amino-acid, whilst the rest is obtained as bases precipitated by phos-
photungstic acid (Z. physiol. Ch. 27, 105 ; 29, 47).
Nitrous acid drives out about ^ of the protein nitrogen as gas (B. 29, 1354).
Thus the large quantities of amino-acids formed by hydrochloric acid are not
previously formed, but are produced by hydrolytic decomposition, especially the
NH2-groups.
Since pepsin digestion constitutes a mild form of hydrolysis, the proteins
acted on by this reagent yield $ of theirjiitrogen as N2 when treated with nitrous
acid, but give no nitroso-reaction — the :NH group is absent. Protein thus
digested and treated with nitrous acid yields aminocaproic acid when boiled with
dilute sulphuric acid, whereby the amino -group can only be called into being by
the hydrolysis (J. pr. Ch. [2] 31, 134, 142).
Since glutin-peptone is a decomposition product of protein in which the
nitrogen occurs in primary, secondary, and tertiary combination (B. 29, 1084),
the above discussed facts hold good for protein also. When it has been shown
that the NH2 -group occurs only in small numbers in the protein molecule, the
larger part of the nitrogen must occur in secondary and tertiary form. The latter,
in particular, must unite together the groups of atoms from which hydrolysis
produces amino acids.
The sulphur present in proteins can be separated up to about one-half as
potassium sulphide, by boiling with alkalis in absence of oxygen ; whilst the other
half can be found as sulphuric acid when the substance is fused with sodium
nitrate and hydroxide, but it is uncertain whether oxidation has taken place
(Z. physiol. Chem. 25, 16). Probably the main portion of the sulphur is contained
in proteins as an atomic complex of cystine (p. 667).
Oxygen is found in the decomposition products other than that in the phenol-
hydroxyl of tyrosine, and the alcoholic hydroxyl in serin e and hyd roxyproline
(p. 677), mainly in the carboxyl groups of the amino acids. Therefore, in the
protein it must exist as COOH, CONH2 and C<H~C^ or C
Moreover, protein is found united with sugar (or hexosamine, such as dextros-
amine), p. 636, forming glucoproteins. If the sugar is split off by the action of
acids, the protein is obtained with all its characteristic properties (Pfliieer's Arch.
85, 281 ; C. 1899, I. 687 ; comp. B. 34, 3241).
It is so far quite unknown how the larger groups of atoms which are found
as decomposition bodies, are arranged in space in the protein molecule.
The physiological significance of the proteins lies mainly in the fact that they
supply the material from which cell -substance is built. Here the protein
is sometimes, perhaps always, in chemical combination with other inorganic and
organic molecules.
It is also remarkable that protein is the only substance which, with water and
salt alone, and without fat and carbohydrates, can preserve animal life ; it can
only partially be replaced by fats and carbohydrates. However copious may be
the supply of food, it will not preserve life if it does not contain a certain quantity
of protein substances. The energy of an animal increases with the content of
protein in a mixed diet.
Like the fats and carbohydrates, ordinary protein is quite indifferent to
atmospheric oxygen, in the absence of ferments. Since the intensity of oxidation
exerted by the living organism, i.e., by the cell-substance, is quite independent of
the iat and carbohydrate content but very dependent on the nitrogen content,
the conclusion has been drawn that protein changes its composition on becoming
itituent of cell-matter, and becomes " active " to oxygen, comparably to
y ell5>w phosphorus among the inorganic substances. In other words, there is a
vast difference between dead and living proteins (Pfliieer, arch. 6, 43 ; 10, 251,
I4239 5422 '' *2778V33 ; 14' lf 63° ;- 18' 247 ; 19' l66 ; 51> 229' 3I7 ; 52'
Fi
Finally, protein establishes its peculiar position in animal metabolism by the
lact, that in the nourishment of the living animal the protein is first and com-
-ely oxidized, and that the fat and carbohydrate are only attacked when the
quantity of protein matter is not sufficient. Thus, the protein metabolism increases
PROTEINS, ALBUMINS 669
within definite limits proportionally to its supply and quite independently of the
supply of fat and carbohydrate ; an increase in fat and carbohydrate has no
deep influence on the former (Pfltiger, etc.).
The nitrogenous derivatives of protein, which are eliminated in the urine,
cannot in general be obtained artificially. The living organism converts protein
by oxidation and cleavage into ammonium salts, which become synthesized
mainly in the liver, to urea, uric acid, and other amido-bodies.
The proteins are usually insoluble in water. Their presence in
the juices or fluids of the living organism is entirely due to the presence
of salts and other substances which are still unknown. They are
insoluble in alcohol and ether ; most of them are precipitated on
boiling in weak acetic acid solution, by acetic acid and potassium
ferrocyanide, or acetic acid and sodium sulphate, and by certain
mineral acids, as well as by salts of the heavy metals ; also, by phos-
photungstic acid, phosphomolybdic acid, potassium mercury iodide
and potassium bismuth iodide, all in the presence of mineral acids ;
further, by acetic and tannic or picric acids, trichloracetic acid, sulpho-
salicylic acid, taurocholic acid, nucleic acid, and chondroitin-sulphuric
acid ; finally, by alcohol in neutral or weakly acid solution.
Many proteins are separated from solution by boiling, by alcohol,
by mineral acids, etc : they are coagulated. Their solubility is entirely
changed. This is not the case with the so-called propeptones, which
when precipitated by alcohol dissolve after the removal of the latter
as readily in water as before the precipitation.
Reactions. — All proteins are coloured a violet-red, like tyrosine, when warmed
with a mercuric nitrate solution containing a little nitrous acid (Millon's reagent).
A yellow colour is produced when they are digested with nitric acid, which becomes
a golden yellow on neutralization with ammonia (Xanthoprotein reaction). The
proteins yield beautiful violet-coloured solutions when digested with fuming
hydrochloric acid. Potassium hydroxide solution and copper sulphate also impart
a red to violet coloration to protein solutions (Biuret reaction) (B. 29, 1354).
On the addition of sugar and concentrated sulphuric acid they acquire a red
coloration, which on exposure to the air becomes dark violet. If concentrated
sulphuric acid be added to the acetic acid solution of proteins they acquire a violet
coloration and show a characteristic absorption band in the spectrum.
The manner of distinguishing and classifying the various proteins
is yet very uncertain. The original proteins, occurring in nature,
are albumin, globulin, casein, gluten proteins, etc., whilst the secondary
modifications obtained from them through the agency of chemicals
or ferments are : acidalbumins, albuminates, coagulated albumins,
fibrins, propeptones, peptones, etc.
Many of these modifications result from the breaking-down of the molecule of
the original protein. It is well worth noting in such instances that the decom-
position product still maintains the essential character of the proteins just as the
starch molecules yield molecules of dextrose, which, like the starch, continue as
carbohydrates. The breaking-down of the original protein, in the reactions
referred to, is proved by a fall in molecular weight. This has been partly
determined by the method of Raoult (p. 16) and in part by testing the
electric conductivity. The decomposition is also evidenced by the fact that the
proportion of the carbon to the nitrogen in the decomposition product frequently
varies from that in the other decomposition product, just as much as it varies
between these substances in the parent body (Schmiedeberg, Arch. exp. Path. 39).
This decomposition of the protein molecule is a hydrolytic decomposition. See
Proteins, p. 666.
670 ORGANIC CHEMISTRY
In a certain number of secondary protein modifications ammonia, sulphur, and
amido-acids, like leucine and tyrosine, etc., have been split off, without the loss of
the essential character of the protein.
Of pre-eminent importance is the fact that the organs of the living animal body
have the power of synthesizing the original protein from the products with lower
molecular weights. This is certainly similar to the formation of glycogen (p. 662)
— the animal starch, from dextrose, in the liver.
1. Albumins, soluble in water, dilute acids and alkalis, dilute and saturated
solutions of sodium chloride or magnesium sulphate. In the presence of acetic
acid the albumins are completely precipitated by saturation with sodium chloride,
magnesium or ammonium sulphate. When heated with sodium hydroxide
solution there is produced the sodium salt of the water-insoluble protalbic acid,
and the water-soluble lysalbic acid (B. 35, 2195). When heated in presence of
neutral salts, the albumins, including serum-, egg-, and lact-albumin, are
coagulated.
2. Globulins, insoluble in water, but soluble in dilute solutions of sodium
chloride and magnesium sulphate. These solutions are coagulated on boiling, and
by saturated solutions of ammonium or magnesium sulphates at 30°, which pre-
cipitate them without any alteration in properties. This class contains : myosin
and musculin (muscles), fibrinogen (in the living blood converted to fibrin
by the fibrin ferment) ; fibrin-globulin ; serum-globulin ; crystal-lens globulin
and vitellin ; also the proteins of the seeds of plants, especially edestin, which
forms a crystalline calcium and magnesium salt, and which has been more
thoroughly examined.
3. The Gluten Proteins are characterized by their physical properties. In
the hydrous state they are pasty, elastic masses. They only occur in wheat flour,
where they constitute the chief essential for bread-making. Gluten is insoluble
in water, and sparingly soluble in water containing a very little dilute acid or
alkali. Its solubility in alcohol (60—70 volume per cent.) is very characteristic.
Some gluten proteins when decomposed yield large quantities of glutaminic acid.
Thus, Ritthausen obtained not less than 25 per cent, of glutaminic acid from
mncedin (see Ritthausen, etc., p. 222). Possibly the liver-proteins are proteins
modified by ferments.
4. Acid Albumins or Syntonins are insoluble in water and salts, soluble in
hydrochloric acid or a soda solution, do not expel carbon dioxide from calcium
carbonate, and are precipitated in acid solution by neutral metallic salts of the
alkalis and alkali earths. Alkali hydroxide converts them into albuminate.
The acid albumins are produced on treating the albumins, globulins, etc., with
hydochloric acid, or with other acids (B. 28, R. 858).
5. Albuminates, insoluble in water and salts, readily soluble in dilute acids
(but precipitated by an excess) and a soda solution, expel carbon dioxide from
calcium carbonate. They can be precipitated without alteration from acid, as
well as alkaline, solutions by saturation with solutions of neutral salts of the
alkalis and alkali earths. The albuminates are produced when albumin,
globulin, etc., are treated with alkali hydroxide (see above, Protalbic and Lysalbic
acids). They cannot be changed by mineral acids into acid albumins, and the
compound from acid albumin and alkali is not an alkali albuminate. The modifica-
tions produced by treatment with mineral acids and alkalis are quite different
bodies,
6. Coagulated Albumins. — They are insoluble in water and salt solutions,
and scarcely soluble in dilute acids. They are obtained by heating other albumins,
or by the addition of alcohol, certain mineral acids and metallic salts.
7. Fibrins, insoluble in water, scarcely soluble in sodium chloride solution, and
in other salts, or in dilute acids, formed from globulin by a ferment (thrombin) in
discharged blood. The process of blood coagulation is expressed according to the
investigations of Schmiedeberg (Arch. exp. Path. 31, 8) by the following equation :
(CinH168N80S035)a+H20=Cl08H]62N80S084+Cn4Hl76N30S087.
Fibrinogen. Fibrin. Fibrinoglobulin.
8. Frppeptones or Albumoses (B. 29, R. 518). Enzymes of the gastric and
pancreatic juices produce modifications of the proteins by hydrolytic digestion,
whereby the protein passes through a series of changes — from the water-insoluble
condition to that soluble in water containing neutral salts or even in pure water,
GLUCOPROTEINS 671
but still precipitated by nitric or acetic acids and potassium ferrocyanide, and
finally not even by these. The albumoses cannot be separated from the mixture
either by neutralization or by boiling, but are completely precipitated by a
saturated solution of ammonium sulphate containing a little acetic acid. The
following is noteworthy : —
" The albumoses cannot be coagulated either by boiling their neutral or acidi-
fied aqueous solutions, nor by the prolonged action of alcohol upon them, although
they are insoluble in strong alcohol, and are precipitated by the latter." *
Prolonged digestion converts them finally into —
9. Peptones, which are perfectly soluble in water, acids, alkalis and salts
of the light metals. They cannot be separated from their solutions either by heat,
nitric acid, by acetic acid and potassium of ferrocyanide, or by ammonium
sulphate. Phosphotungstic acid precipitates the peptones in the presence of
hydrochloric acid ; mercuric chloride, basic lead acetate, alcohol, etc., incompletely.
Proteins, when acted on by pepsin and dilute hydrochloric acid at 30-40°,
are dissolved, completely digested, and at first are converted into syntonins
or acid albumins, then into albumoses or propeptones, and finally into
peptones, which dissolve readily in water, are not coagulated by heat, and are
not precipitated by most reagents (B. 16, 1152 ; 17, R. 79). For the molecular
weight and constitution of the peptones consult B. 25, R. 643 ; 26, R. 22. The
lowering of molecular weight of the protein molecule by digestion, indicates that
it has been broken down. That hydrolysis has taken place is most clearly shown
by the action of nitrous acid which evolves much less nitrogen from proteins than
from the albumoses or peptones ; and also by obtaining by boiling with acids
without ferments, or by merely heating in presence of water, the same bodies as
by digestion (see p. 667). Further, the pancreatic enzyme and the ferments of
putrescence also produce true peptones from proteins. The gastric enzyme does
not act in neutral solution, contrary to that of the pancreas, which not only
converts proteins to peptones (like the gastric ferment) but also splits them into
amino acids and bases (Hedin, Dubois-Reymond's Arch. 1891, 273 ; Kutscher,
Z. physiol. Ch. 25, 195 ; Kossel, Z. physiol. Ch. 25, 194). It is therefore note-
worthy, that in the case of carnivors, at any rate, the purely meat portion of the
food is only dissolved in the stomach (Pfluger's Arch. 77, 438).
The artificially synthesized di- and polypepiides which have already been dis-
cussed (pp. 390, 543, 555) resemble the peptones, in that many of them are
broken down by pancreatic juice to the simpler amino-acids, as happens with
the peptones themselves.
There exists a whole series of bodies more or less closely connected with the
proteins. Some are even more complicated than the proteins themselves because
they are compounds of them ; others possess the characteristics of the more or
less decomposed protein molecule.
A. GLUCOPROTEINS
These bodies yield proteins and sugar or aminocarbohydrates when boiled
with mineral acids (Eichwald, A. 134 ; Pavy, The Physiology of the Carbohydrates,
tr. into German by K. Grube, 1895, Hofmeister, Z. physiol. Ch. 24, 169 ; Mutter
and /. Seemann, Deutsche med. Wochenschr., 1899, m. 13 ; Seemann, Arch. J.
Verdauungskrankheiten, IV. 1898).
They are sub-divided into —
(i) The glucoproteins, which almost completely resemble the true sugar-free
proteins in elementary composition and in all reactions, and which includes
ovalbumin of birds' eggs (Hofmeister, Z. physiol. Ch. 24, 169). This group is not
absolutely established, partly because of the impurity of the parent substances,
and because a solution of the ovalbumin can be crystallized out from the dextrose
compound (ovomucoid) ; partly because such trustworthy chemists as K. Morner
or Spenzer could not obtain a sugar from purified ovalbumin ; and partly because
the glucoproteins almost completely resemble the sugar-free proteins in elementary
composition and all other reactions.
* Lehrbuch der phys. Chcmie von R. Neumeister, S. 229 (1897).
672 ORGANIC CHEMISTRY
(2) The Mucins are poorer in carbon and particularly in nitrogen, and are
richer in oxygen than the glucoprotelns, probably on account of their larger sugar
content. They are not coagulated when boiled in neutral or weakly alkaline
solution ; nor by acetic acid and potassium ferrocyanide in presence of sodium
chloride ; but are precipitated by an excess of acetic acid. They form ropy
solutions.
(3) The chondroglucoproteins are compounds of protein or gum with chondroitm
sulphuric acid (p. 673).
(4) The Mucoids, Mucinogens and Hyalogens include a large number of sub-
stances which belong to this section, such as ovomucoid, pseudomucin of the
ovarial cysts, etc., but which have only been investigated to a small extent.
B. PHOSPHORPROTEINS
These bodies consist of proteins with which phosphoric acid is combined in a
peculiar manner.
(1) The Nucleins. When various cell-substances are dissolved with gastric
juice there remains behind the insoluble cell nucleus (Meischer, Hoppe-Seyler's
Med.-chem. Untersuchung, p. 451). This is nucle'in, which can be purified by
solution in dilute alkalis, precipitation with dilute acids and final washing with
alcohol and ether. Boiling mineral acids or alkalis split the nucleins into albumin
and nucleimc acid. This is further decomposed when boiled with mineral acids
into phosphoric acid, uracil bodies (see uracil, crytosine, thymine, p. 574), purine
bases (see xan thine, guanine, adenine, hypoxanthine, p. 587), and other bases
not clearly recognized. According to Liebermann, nuclem contains metaphos-
phoric acid (B. 21, 102). Some nucleins yield carbohydrates on decomposition,
such as hexoses and pentoses (comp. 1-Xylose, p. 619). (See constitution of
thymus nucleic acid, B. 41, 1905.) Nucleic acid and albumin in acid solution give
a precipitate, which is included among the nucleins (Z. physiol. Ch. 22, 80).
(2) Para- and pseudo-nuclems are differentiated by their yielding albumin and
phosphoric acid, but no purine bases when boiled with mineral acids. They can
be artificially prepared by the action of metaphosphoric acid on albumin (Pfluger's
Arch. 47, 155 ; B. 21, 598). The proteins remaining insoluble after the action of
pepsin on paranucleins, are known as nucleo-albumins, to which class milk-casein
belongs.
Casein is dissolved in milk in the form of a salt containing the percentage
composition of a protein with 0-85 per cent, of phosphorus. It is precipitated
by dilute acids, as it is insoluble in water. Solution in alkalis and precipitation
by acids is employed for its purification. Sodium chloride or magnesium sulphate
precipitates it from its solution without change, and it can be purified by a repeti-
tion of this process. Decomposition of casein with concentrated hydrochloric
acid leads to the formation of all the hydrolytic decomposition products referred
to on p. 677, together with diamino-trihydroxy-dodecanoic acid (E. Fischer, I.e.
p. 736). For chlorocasein and its decomposition product, see C. 1901, II. 690).
A solution of the alkali or calcium salt of casein does not coagulate when
heated.
A calcium-free solution of casein is not coagulated by rennet, but coagulation
occurs on the addition of a calcium salt, even after the rennet has been rendered
inactive by boiling. Rennet probably causes a decomposition of the casein into
protein which is precipitated (paracasein) and a soluble protein (milk albumin).
The paranuclcin which is left behind after the action of gastric juice on casein
is finally completely dissolved (Salkowsky, Pfliiger's Arch. 50, 225).
That portion of the casein molecule with which the phosphoric is combined
is attacked only with difficulty during hydrolytic decomposition ; so that at a
certain period during reaction, this behaves as a paranuclein, and would be called
a true nuclein if it also contained xanthine bases.
The following class of substances have much in common, though
to a diminished extent, with the decomposition products of the
proteins,
GELATIN 673
c. GELATIN (DERIVATIVES OF INTERCELLULAR MATERIALS)
Certain nitrogenous animal tissues, when boiled with water yield
glutins, and form the major portions of the intercellular substances —
they are true collagens.
That they are formed from albumin is shown by their absence
in birds' eggs before incubation, and their first appearance in the
embryo ; also, by the young of herbivorous animals which take only
milk (which contains no gelatin), still continuously producing large
quantities of collagen tissue.
Glutin, Gelatin, Bone Glue, swells in cold water, and dissolves on boiling to
a sticky liquid, which gelatinises again on cooling. Concentrated acetic acid or
boiling dilute sulphuric acid destroys this power of setting (fluid glue}.
Gelatin has approximately the elementary composition of the proteins, except
that it contains less sulphur. It rotates the plane of polarization to the left.
Solutions of gelatin are precipitated by acetic acid and sodium chloride or
potassium ferrocyanide (excess ol the latter, however, redissolves it), also by
mercuric chloride and hydrochloric acid or sodium chloride, by metaphosphoric
or phosphotungstic acid and hydrochloric acid, or potassium mercury iodide and
hydrochloric acid, or by saturation with ammonium sulphate.
Tannic acid precipitates gelatin tannate as a yellow sticky precipitate. It
also combines with substances which yield gelatin, and forms leather. Gelatin
solutions give the Millon and biuret reaction ; also a feeble xanthoprotein colour.
Dry distillation of gelatin gives rise to the formation of pyrrol* and pyridine
bases (bone oil). Oxidation with permanganate produces ox amide (which also
results from other proteins) and guanidine (from arginine, p. 667) ; and, with
acid hydrogen peroxide, acetone and isovaleraldehyde (probably from leucine)
(C. 1902, II. 340).
When gelatin is boiled with concentrated hydrochloric acid the same decom-
position products are obtained as from albumin — glycocoil (about 16-5 per cent.)
leucine, proline, oxyproline, also serine, aspartic acid, glutaminic acid, alanine,
phenylalanine, arginine, etc. (E. Fischer, I.e. pp. 671, 680, 739), but no tyrosine and
tryptophane, and in the case of putrescence, no tyrosine, indole and skatole.
Gentle action of hydrochloric acid produces the alcohol-soluble glutin-peptone
hydrochloride. The action of nitrous acid on the glutin peptone shows that it
contains primary and secondary, as well as tertiary amino groups (B. 29, 1084).
Longer action of approximately a 12 per cent, hydrochloric acid solution gives
rise to glutokyrine (a glutin-peptone), which appears to be formed, together with
glutaminic acid and glycocoll, from arginine andlysine (C. 1903, 1. 1144). Tryptic
digestion of gelatin produces a dipeptide anhydride prolyl glycine anhydride
(p. 543) (comp. B. 40, 3544).
Although gelatin is very similar to albumin in its composition, it cannot
replace it in animal metabolism.
According to the substitution of calcium and magnesium salts, fat, etc., into
those tissues which can supply gelatin, bone-fat and cartilage result.
" The cartilage-gelatin, or chondrin of some authors, obtained by boiling
ordinary cartilage, consists of a mixture of gelatin, and certain compounds of
chondroitin sulphuric acid with gelatin- or protein-like substances on the one
hand and alkalis on the other " (Schmitdeberg, Arch. exp. Pathol. u. Fharmakol.
28 ; Morner, see p. 655, footnote; Hammavsten, p. 322).
Chondroitin Sulphuric Acid is, in its structural details, a still unelucidated
condensation product of sulphuric acid, acetic acid, and a pclysaccharide amide
or its corresponding acid (A. 351, 344). An arti€cial mixture of gelatin and
chondroitin sulphuric acid salts give the reaction of chondrin. Amyloid, which
appears pathologically in concentrically arranged layers of grains, and in the
arterial walls, belongs to the chondroprotelns, and also contains chondrc
sulphuric acid.
Chitin is the chief compound of the shells of crabs, lobsters, and other arti-
culates. Krawkow (Z. L Biol. 29, 177) considers that the chitin m shells is com-
bined with a protein-like substance, and occurs in various modifications. It is
VOL. I. 2 X
674 ORGANIC CHEMISTRY
noteworthy that here also the nitrogen is contained as dextrosamine (p. 636), since
the cleavage of chitin by hydrochloric acid yields dextrosamine and acetic acid
(Ledderhose, Z. physiol. Ch. 2, 224). In that case the equation should hold
(Schmiedeberg, etc.) :
C18H80N2012+4H20 = 2C6H18N06+3CH3C02H.
Chitin. Dextrosamine. Acetic Acid.
When chitin is fused with potassium hydroxide at 184° it is converted into
acetic acid and chitosan, which, when heated with hydrochloric acid is split up
into acetic acid and dextrosamine (B. 28, 32). The stiffening material of fungi is
probably identical with chitin, so that the mycosin, obtained from it by potassium
hydroxide is identical with chitosan (B. 28, 821, R. 476 ; C. 1908, II. 2016).
Elastin differs from albumin by its low sulphur content, and by its hydrolysis
to glycocoll (25*75 per cent.) leucine (21*38 per cent.), alanine, phenyl alanine,
valine, proline and glutaminic acid (C. 1904, I. 1364). Keratin, the main com-
ponent of hair, nails, etc., possesses a very variable and sometimes particularly
high sulphur content (0-7 to 5 per cent.) (B. 28, R. 561) ; but in spite of this, its
percentage composition is close to that of the proteins. Keratin yields almost the
same products as albumin, viz., leucine, tyrosine and serine (B. 35, 2660). Elastin
and Keratin are more difficultly soluble and decomposable than the true protein
substances. Elastin is digested by pepsin and trypsin, but not keratin. Partial
hydrolysis of elastin gives rise to several dipeptides — d-alanyl l-leucine, glycyl
valyl anhydride, d-alanyl prolyl anhydride (B. 40, 3544).
Fibroin is the chief substance in silk which also contains silk glue ; this is de-
composed mainly into serine (p. 546). When left in solution in contact with cold
concentrated hydrochloric acid it is converted into a peptone-like body, from
which trypsin only produces tyrosine. The remaining peptone-like body is de-
composed by acids or alkalis into glycocoll and d-alanine, or glycyl d-alanine (Ch.
Ztg. 1902, 940). Also, a tetrapeptide, made up of glycocoll, alanine and tyrosine
has been isolated by partial hydrolysis of silk-fibroin (B. 40, 3552).
Protamines, discovered by Meischer (Arbeiten, Leipzig, 1897) are obtained by
treatment of fish-sperm with mineral acids. Hydrolytic decomposition and action
of trypsin produce lysine, arginine and histidine (Kossel, Z. physiol. Ch. 25, 165 ;
B. 84, 3233 ; C. 1905, I. 1721). The protamines are free from sulphur and
phosphorus, and react with the biuret test, but do not give Millon's reaction.
Haemoglobin occupies a position in physiology of the highest importance, and
has been minutely studied chemically. In connection with this chlorophyll will
be discussed, whilst the related gall-dyes will be found in the section biliary
substances.
D. HEMOGLOBINS
The oxyh&moglobins are found in the arterial blood of animals and may be
obtained in crystalline form by the addition of alcohol to an aqueous solutio'n of
blood corpuscles, after cholesterol and lecithin have been removed by shaking
out with ether. The different oxyhaemoglobins, isolated from the blood of various
animals, exhibit some variations, especially in crystalline form. Their elementary
composition approximates very closely to that of albumin. It differs, however,
by an iron content of 0-4 per ce'nt. If the molecular weight of haemoglobin be cal-
culated in the supposition that it contains an atom of iron, the value obtained
exceeds 13,000. The haemoglobins are bright red, crystalline powders, very soluble
in cold water, and are precipitated in crystalline form by alcohol. When the
aqueous solution of oxyhaemoglobin is placed under reduced pressure or when it
is exposed to the agency of reducing agents (ammonium sulphide) it parts with
oxygen and becomes hemoglobin. The latter is also present in venous blood, and
may be separated out in a crystalline form (B. 19, 128). Its aqueous solution
absorbs oxygen very rapidly from the air, and reverts again to oxyhaemoglobin.
Both bodies in aqueous solution exhibit characteristic absorption spectra, whereby
they may be easily distinguished.
If carbon monoxide be conducted into the oxyhaemoglobin solution, oxygen
is also displaced and haemoglobin-carbon monoxide formed, which can be obtained
in large crystals with a bluish colour. This explains the poisonous action of
Carbon monoxide.
CHLOROPHYLL 675
The bluish-red solution of carbon monoxide in haemoglobin, like oxyhasmo-
globin, shows two characteristic absorption bands between the Fraunhofer lines
D and E, which do not disappear on the addition of ammonium sulphide (method
of differentiation from oxyhaemoglobin). Oxygen-free haemoglobin shows one
absorption band between D and E. =CO and O2 enter into combination in equal
volumes ; it is, therefore, not a question of molecular attraction, but actual
atomic union : Hb=COandHb<^ |. These compounds are partially dissociated
NO
above o°. Equivalent quantities of other gases, such as NO4, HNC, are absorbed
by haemoglobin. Haematochromogen (below) also absorbs one equivalent of CO.
At 70°, or by the action of acid or alkalis, oxyhaemoglobin is split up into
a protein such as globin (hydrolysis, see E. Fischer, I.e. 695, 740), differing
for each animal, fatty acids and the colouring matter hamatochromogen ; the
latter substance, in contact with free oxygen passes into haematin. It contains
9 per cent, of iron, and corresponds with the formula C84H8RFeN4O6 (Hoppe-
Seyler), C8aH32N4FeO4 (Nencki and Sieber) or C32H34N4FO8 (Hufncrand Ktister).
If one drop of glacial acetic acid and very little sodium chloride be added to
oxyhaemoglobin (or dried blood), microscopic reddish-brown crystals of hamin or
hcsmatin chloride, C34H33N4O4FeCl (?) are formed (B. 29, 2877 ; 40, 2021 ; A. 358,
213), from which alkalis precipitate htzmatin, C34H33N4O2FeOH. The formation
of these crystals serves as a delicate test for the detection of blood. The structural
formula of haematin appears to be near its elucidation.
Oxidation with potassium bichromate breaks haematin down into the imide
CH,C— OX
of the tribasic h&matic acid, \\ /NH, m.p. 114°, which yields
HOOC.CH2CH2.C— COX
the corresponding anhydride acid, CBH7(CO2H)(CO)2O, m.p. 97° when treated
with alkalis. When heated above 120° it loses CO2 and passes into the imide of
the dibasic methyl ethyl maleic acid (comp. p. 519).
When haematin is treated with hydrobromic acid it loses iron and is converted
into hfsmatoporphyrin, C34H38N4Oft. Gentle action of hydriodic acid and phos-
phonium iodide produces mesoporphyrin, C34H88N4O4 ; more energetic treatment
gives rise to an oxygen-free, volatile, easily altered oil, hesmopyrrole, C8H]8N. It
is probably an alkylated (methyl propyl?) pyrrole (Vol. II.), the more probably
since the breaking-down of haematin (see above) by oxidation, gives rise to alkyl-
ated maleic acid (B. 34, 997 ; C. 1906, 1. 1026).
CHLOROPHYLL
Under this heading are collected those vegetable colouring matters which occur
in all the green portions of plants, and which play a r61e of the highest importance
in physiological development in the vegetable, and therefore indirectly animal,
kingdoms.
It is remarkable that chlorophyll, the green vegetable colouring matter, and
hajmin, the colour in red blood, appear to be closely connected (p. 676). What
iron is to haemin, magnesium is to chlorophyll (Willstatler).
Amorphous chlorophyll is obtained by extracting the fresh or dried green parts
of plants with alcohol, and the liquid thus formed is purified by shaking out with
benzene or carbon disulphide and water. Purified chlorophyll is an amorphous
green mass, still probably consisting of a mixture of substances, the ash of which
consists of magnesia. Magnesium in the chlorophyll can be abstracted by dilute
acids and neutral ash-free substances result — chlorophyllan, phaeophytm, pnyl-
logen', etc. (comp. A. 354, 207 ; B. 41, 1352 ; C. 1908, II. 952). These seem
to be partially of ester-like character, since hydrolysis with alcoholic potassium
hydroxide liberates an alcohol phytol, C20H40O, b.p.0.08 145°, D0
the acid portion consists of a mixture of substances, phytochlonne and phytorhodin
Alkalis' are not able to separate the magnesium even at 200°, but rather con-
vert the chlorophyll into other substances containing magnesium, such zsrhodo-
phyllin etc (A 358, 205), from which dilute acids again produce ash-free bodie
A similar treatment converts chlorophvll into phylloporphyrin, which is closely
I
676 ORGANIC CHEMISTRY
similar to raesoporphyrin and haematoporphyrin (p. 675), as shown by its formula,
C84H3,N4Oa (?), its chemical reactions — it yields a pyrrole derivative, similar to
haemopyrrole — and its absorption spectrum (Schunk and Mar Mew ski, A. 290,
306 ; B. 29, 2877 ; 34, 1687 ; 41, 847).
The chemical relationship between haemoglobin and chlorophyll indicates an
analogous physiological activity ; haemoglobin takes up the oxygen from the air
breathed into the lungs and gives it up to those organs of the body which require
it, whilst chlorophyll abstracts oxygen from carbon dioxide and water and gives
it'up for the use of the animals.
Since the lower fungi which contain no chlorophyll are able to build up carbo-
hydrates, fats, and proteins from many different bodies containing the groups
CH 2 and CHOH, there can be no doubt this synthesis is carried out by the living
cell -substance to which the required atomic groups are delivered by reduction in
the green parts of the plant (private information from E. Pfliiger).
Crystallized chlorophyll, CagH^OjlS^Mg (?) and its reaction products, see A.
358, 267 ; C. 1908, II. 715).
Carotin and Xanthophyll are red and yellow colouring matters which occur
with chlorophyll in leaves, and give rise to the autumn colours.
Carotin, C40H6e, m.p. 168°, is also obtained from carrots (Daucus carota) ;
it forms red crystals.
Xanthophyll, C40H66O2, m.p. 172°, forms yellow crystals. It is characterized
by its beautiful iodine addition products ; it absorbs oxygen energetically, and
may be of significance in connection with the oxygen-breathing of plants as chloro-
phyll is for the CO, breathing (A. 355, i).
E. BILIARY SUBSTANCES
In the bile, the liquid secretion of the liver which assists in the emulsifying
and absorption of fats, there exist a connected series of peculiar acids in the form
of their sodium salts. The best known are glycocholic acid and taurocholic acid ;
also lecithin (p. 531), cholesterol, and some bile pigments.
Bilirubin, Bilifuscin, Biliprasin, C32H86N4O«, (?), is closely connected with the
blood pigment. When oxidized with chromic acid it yields biliverdic acid, identical
with hamatic acid (p. 675) (B. 35, 1268 ; C. 1905, I. 1253, 1906, I. 1498).
Cholalic Acid, Cholic Acid, m.p. anhydrous 195° (B. 27, 1339 ; 28, R. 233 ;
29, R. 142), is obtained together with glycocoll when glycocholic acid is broken
down, and with taurin when taurocholic is similarly acted on. It is a mono-basic
acid. Glycocholic and taurocholic acids occur as sodium salts in bile. In the
preparation of cholalic acid, choleinic acid, C24H40O4 and fellic acid, C28H88O4, are
also formed. Iodine produces a blue compound similar to that between iodine
and starch (B. 28, 785, R. 720). On the oxydation of cholic acid, see B. 32, 683.
Glycocholic Aeid,C24H39O4.NHCH2CO2H, m.p. 153°, decomposes into cholalic
acid and glycocoll (p. 385) when boiled with aqueous alkali hydroxides.
Taurocholic Acid, C24H8,O4.NH.CH2CH2SO8H (ravpos^ox, Xo\4 = bile) is
easily soluble in water and alcohol, and is decomposed when boiled with water
into cholalic acid and taurine (p. 326).
Cholesterol, C27H45OH, m.p. 148°, b.p. about 360°, [a]D=— 31-12° (in ether)
occurs, partly free and partly as an ester with the higher fatty acids, in many
parts of the animal organism, not only in the bile (xoAf?=bile, (Treap= tallow),
but also in gall-stones, which contain 90 per cent, cholesterol, in the brain, blood,
egg-yolk, wool-fats, etc.
In the intestine cholesterol is reduced to coprosterol, Ca7H47OH (?), m.p. 96° ;
a dextro-rotatory saturated alcohol (B. 29, 476 ; C. 1908, II. 1279, 1500).
Cholesterol protects the red blood corpuscles from haemolysis by certain toxins ;
it acts, therefore, against invading poisons (C. 1905, I. 1265 ; B. 42, 238).
Cholesterol is insoluble in water, but soluble in most organic solvents. It
crystallizes from alcohol in mother-of-pearl leaflets or tables possessing a fatty
feel, and containing one molecule of water ; from ether it forms anhydrous
needles. It is a secondary olefine alcohol, it takes up HC1, bromine (dibromide,
^27H4BBr2OH, m.p. 125°, serves to characterize it), and hydrogen^dihydroc holes-
terol, C27H47OH, m.p. 142°, B. 41, 2199).
Cholesteryl Chloride, CS7H4BC1, m.p. 96°, is formed from cholesterol and
UNORGANIZED FERMENTS OR ENZYMES 677
thionyl chloride ; sodium and amyl alcohol reduce it to cholestene, C,7H4t,
m.p. 90° (B. 27, R. 301). The esters of cholesterol were the first discovered
substances found to possess a crystalline fluid condition (p. 46).
When heated to 310° cholesterol is partly converted into the (stereo- ?) isomeric
^-cholesterol, m.p. 160°, which can also be formed by reduction of cholestenone,
Ca7H44O, the ketone corresponding with cholesterol. It can be reconverted into
the ordinary form of cholesterol through the benzoate (B. 41, 160).
Cholesterol contains only one define bond, and, as is shown by its C : H ratio,
a carbon ring ; and is connected with the terpenes (Vol. II.). Its structure has
been partially elucidated by an examination of its oxidation products (Mauthner,
Suida, Dials, Abderhalden, Windaus ; B. 41, 2558, 2596). Without examining
the matter in detail, it suffices to give the following provisional formula : —
rw r w <^CH2CH2CH(CH3)t
CW a Ox 7 hi ae \CH
CHOH— CH2 £H
According to this, chlolesterol is a polycyclic, secondary ring alcohol, with
several side chains, among which an isoamyl and a vinyl group are to be identified,
the latter giving easy opportunity for further ring formation, similarly to what
happens among the olefinic terpenes (Vol. II.).
Cholic acid (p. 676) should be related to cholesterol, but still more closely
allied appears to be chenocholic acid, C27H44O4, which occurs in the bile of geese
(A. 149, 185).
The esters of cholesterol and isocholesterol, m.p. 138°, with the higher fatty acids
are the constituents of lanolin or wool fat which is found on uncleaned sheep's wool,
and is employed as an ointment, since it has the peculiarity oi being absorbed by
the skin.
In the mixture of soaps, resulting on saponification of lanolin, there have been
isolated lanoceric acid, C30H60O4, m.p. 104°, lanopalmitic acid, C16H82O8, m.p. 87°,
myristic acid (p. 262) and carnaubic acid, C24H48O2 (B. 29, 2890).
Cholesterol-like substances have been found in plants. Phytosterol, isomeric
with cholesterol, occurs in seeds and plant-germs (B. 24, 187). a- and fi-Amyrin,
from Elemi resin (B. 24, 3836), and lupeol (B. 24, 2709) from the seed husks of
Lupinus luteus are other examples. Hippocpprosterol, or chortosterol, Ca,H63OH,
m.p. 79° (C. 1908, II. 1277).
F. UNORGANIZED FERMENTS OR ENZYMES
(Comp. p. 113.)
The unorganized ferments, which play an important r61e in fermentation,
many putrescing processes, and digestion, are produced from animal and vegetable
cells. They are of unknown structure, soluble in water, and lose their activity
on being boiled. Their influence is mainly hydrolytic. It is striking that for
the hydrolytic decomposition of different substances, almost always different
enzymes are required. Pepsin and trypsin hydrolyze proteins but not fats or
starch ; the diastatic ferment of saliva hydrolyzes starch, but has no action on
fats. The configuration of glucosides has a definite influence on the action of
enzymes (B. 28, 984, 1429). Vegetable enzymes are : invertin, diastase (p. 113),
emulsin or synaptase in bitter almonds, papayotin, from the fruit^of the paupaw
(Carica -papaya], all producing far-reaching decomposition of proteins (B. 35, 695).
Nomenclature of enzymes (B. 36, 331).
On the inclusion of zymase, the active fermentative principle in the ]uice
expressed from yeast, as an enzyme (see p. 112).
INDEX
SUBSTANCES should also be sought in the more general Paragraphs of the
various sections and derivatives^ also under the various compounds.
ACBCONITIC Acid, 595
Acediamine, 282
Acetaconitic Ester, 613
Acetal, Acrolein. 215, 534
Acetaldehyde, 30 63, 163, 199, 249, 256, 258,
312, 318, 425, 631
Cyanhydrin, 288, 379
Disulphonic Acid, 210, 847
Hydrazone, 213
Semicarbazone, 447
Substituted, 201, 343
Acetaldoxime, 152, 213, 283
Acetal Malonic Acid, 402
Acetal Malonic Esters, 561
Peroxide, 204
Acetals, 195, 200, 204, 205, 340
Glycol, 837, 338, 340
Acetamide, 277, 278
Acetamidine, 282
Acetethylamide, 277
Acetic Acid, 255, 298, 396, 526
Amino-derivatives, 382, 388, 389, 390
Derivatives, 258,260,261, 366, 384,
388, 401, 574, 651
Halogen Substitution Products ot,
287
Isonitramtne, 397
Sulphur Derivatives, 376, 377- See
also Thio-acids
Anhydride, 273, 475
Ester, Diethylamine, 387
, Ethyl Sulphonic Fthyl, 377
Nitrourethane, 396
Esters, 267
Acyl and Alky 268, 401, 547, 548
Ether, 267
Acetimido-Ethers, 281
Acetimido-Thio-ethers, 282 ;
Ace tins, 530
Acetoacetic Acid, 218, 222, 410, 516
Acyl, 546, 599
Alkyl, 259, 353, 420, 421
Derivatives, 419, 421
Aldehyde, 343
Ester, 38, 253, 256, 262, 263, 267, 296, 347,
350, 370, 372, 377, 380, 398, 411, 412, 418, 486,
502, 504, 534, 556, 571, 572, 574, 581, 585, 599
Acetonyl, 351, 648
Acyl, 419, 425, 545, 547, 548, 599
Alkyl and Alkylidene, 232, 254, 355,
407, 419, 425, 519, 531, 544, 548, 568
Cyano-derivatives, 556, 570
Derivatives, 353, 416, 447, 546, 556,
569, 609, .655
Ethers of, 418
Halogen Substitution Compounds, 419,
420, 421, 423, 544, 545
Homologues, 412 ; acid decomposi-
tion, 415: ketone decomposition, 415; ester
decomposition, 416
Hydroxy-derivatives, 374, 4*9, 545
346, 598
Sulphur Compounds, 543
Acetoamides and Derivatives, 277
Acetoamylamide, 277
Acetobenzalhydrazine, 278
Acetobromamide, 277
Acetobromarabinose, 618
Acetobromogalactose, 635
Acetobromodextrose, 634
Acetobutyl Alcohol, 342
Acetobutyric Acids, 342, 423, 424
Acetochlorarabinose, 618
Acetochlorodextrose, 634, 658
Acetochlorogalactose, 635, 658
Acetocitric Ester, 611
Derivatives, 419, 548
Acetoethylidine Propionate, 207
Acetoglutaric Ester. 570
Acetoguanamine, 474
Acetohydrazide, 278
Acetohydroxamic Acid, 151, 288
: — Derivatives, 284
Acetohydroximic Acid Chloride, 283
Acetohydroxyamido-oxime, 284
Acetom, 341
Acetolasvulinic Acid, 423
Acetol Ether, 341, 841, 527
Formate, 341
Acetomalonic Monoester Anilide, 564
Acetone, 63, 89, 90, 222, 257, 313, 314, 341, 411,
Alcohol, 341
Anilide, 569
Bisulphonic Acid, 377
Carboxylic Acids, 410, 488, 568, 6ia
Chloride, 225
Chloroform, 222, 365
Cyanacetyl Derivatives, 599, 647
Cyanhydrin, 379
Diacetic Acids, 670, 571
Dialkyl Sulphone, 226
Dihydroracemic Acid, 571
Dilactone, 496
Dioxalic Ester, 621
Dipropionic Acid, 571
Ester Cyanhydrin, 611
Ethyl Mercaptol, 226
Formyl, 348
Formyl Acetyl, 536
Mercarbide, 223
Methenyl Bisacetyl, 598
Oxalic Ester, 547
.- Oxalyl Bisacetyl, 647
Peroxide, 224
Phenylhydrazone, 228
Rhamnose, 619
Semicarbazone, 228, 447
Acetonic Acid, 365
Acetonitrile, 280, 401
Acetonitrodextrose, 634
Acetonitrogalactose, 635
Acetonyl Acetoacetic Ester, 351, 34*
Acetone Dioxalic Ester, 655
Acetones, 310, 851, 537
68o
INDEX
Acetonyl Acetonosazone, 356
Laevulinic Acid, 548
Urea, 443
Acetopropionic Acid, 421
Aldol, 339
Acetoprapyl Alcohol, 315, 342
Acetonitrolic Acid, 283
Acetonitrpso-oxime, 284
Acetonuria, 365
Acetonyl Acetone Dioxime, 355
Acetosuccinic Esters, 568
Acetosuccinimide, 568
Aceto-tert.-Butylamine, 227; Nitraminc, 227
Acetotricarballylic Esters, 612
Acetoxime, 227
Derivative, 405
Ethyl Ether, 227
Acetoximic Acid, 354
Acetoxycrotonic Ester, 419
Acetoxy-dimethyl-acetoacetic Ester, 421
Acetoxyglutaric Ester, 559
Anhydride, 559
Acetoxymesityl Oxide, 343
Acetoxypivalic Acid, 370
Acetoxypropionaldeyhde, 338
Acetoxyl Acetyl Butyric Ester, 545
Oxaraide, 484
Acetoxymale'ic Anhydride, 565
Acetoxymale'inanil, 565
Acetyl Acetone, 350
Derivative, 534
Salts, 351
Chloral, 598
Dioxirae, 355
Aceturic Acid, 338
Acety) Acetic Acid, 410
Acetoacetic Ester, 419
Derivative, 548
Acetonamine, 345
Acetone, Amino-compounds, 345
Acetoxyl Valerolactone, 422
Bromide, 271
Butyryl, 349
Methane, 351
Caproyl, 349
Caprcyl Methane, 232, 351
Carbinols, 341
Carboxylic Acid, 303
Cellulose, 665
Chloride, 270
Chromate, 271
Cyanacetic Ester, 564
Cyanide, 409
Cyano-imino-propionic Ester, 417
Dialuric Acid, 577
Dibromacrylic Acid, 425
Dithiourethane 450
Formic Acid, 407
Formyl, 348
Formyl Chloride Oxime, 244
Formyl Oxide, 273
Glutaric Acid, 570
Glycocoll, 388
Glycoliic Acid Nitrile, 379
Glyoxglic Acid, 546
Derivatives, 547
Glyoxyl Urea, 574
Hydantoln, 442
Imidodithiocarbonic Ester, 450
Iminosuccinamic Ester, 609
Iminosuccinimide, 609
• Iodide, 271
Isobutyric Acid, 423
Isobutyryl Methane, 351
• Isocaproyl, 349
— Isocyanate, 462
— - Isovaleryl, 349
• Ketones, 351, 537
— — Lactic Acid, 368
— — Lsevulinic Acid, 42*
Leucine, 390
• Malic Acid. 552
— — Malonanilic Acid Ester, 419
•— Maloiuc Acid, 564
Acetyl Malonic Ester, 419
Methyl Isourea, 446
Methyl Nitrolic Acid, 409
Nitrite, 271
CEnanthylidene, 832, 351
Oxide Formyl, 272
Peroxide, 273
Propionyl, 349
— Hydrazones, 355
Methane, 351
Osazone, 356
Semicarbazone, 355
Pseudothiourea 453
Pyroracemic Chloralide 347
Ester, 547
Sulphide, 274
Thiocarbamic Ester, 449
Thiocarbamide, 471
Trichlorophenomalic Acid, 425
Uramil, 578
Ureas, 160, 441, 442
Ure thane, 436
Acetylene Alcohols, 125
Aldehydes, 199, 215
and Polyacetylene Dicarboxylic Acids, 523
Bromide, 98
Carboxylic Acids, 802, 304
Chlorides, 96, 98
Bromides, 96, 98
Dicarboxylic Acid, 501, 523
Dinitrodureine, 441
Diurea, 441
Glycols, 315
Iodides, 98
Ketones, 232
Mercury Chloride, 246
Urea, 573
Acetylenes, 64, 67, 72, 81, 85, 86, 88, 95, 225, 239
337, 347, 348
Metallic Derivatives, 88
Achroo-dextrin, 663
Aci-, explanation of term, 40
Acid Amides, 162, 274, 277, 281
Anhydrides, 271
Azides, 160, 278
Bromides, 270
Chlorides, 269
Cleavage, 415. 566
Fluorides, 270
Halides, 269
Hydrazides, 278
Iodides, 270
Nitriles, 247
Peroxides, 273
Acidum Aceticum, 253
citricum, 610
formicum, 236
inalicum, 551
mucicum, 654
oxalicum, 480
tartaricum, 603
trichloraceticum, 287
Aconic Acid, 402, 501, 561
Aconitic Acid, 594, 610
Derivatives, 595, 615, 623
Ester, 523
Aconitimide Acid, 595, 611
Aconitum napellus, 594
Acritol, 628, 624, 632 636
Acrolein, 203, 214, 294, 338, 527
Acetal, 215
Alykl Derivatives, 215, 306
— — -ammonia, 215
Bromide, 636
Cyanhydrin, 397
Acrose, 215, 337, 534, 6*3, 624, 626, 632, 634,
636
Acryl Chloride, 294
Acrylic Acid, 294
Acyl, 402, 425
Alkyl, 291, 292, 299
Derivatives, 399, 401,571
Acyl Glycoliic Nitriles, 379
Thiocyanates, 471
INDEX
681
Acyloins, 341, 349
Adenine, 587, 589
Adipic Acids, 496, 604, 505, 621
Acid, Derivatives, 299, 560, 606, 621, 653
Dialdehyde, 348
Dinitrile, 505
Adonis vernalis, 616
Adonitol, 615, 616, 621
^Ether aceticus, 267
anaestheticus, 135
bromatus, 135
Agaricus Muscarius, 340
Agave americana, 66 1
Agavose, 661
Alanine, 363, 364, 381, 388, 390. 893, 541, 667,
674
Alanyl, 392
Benzoyl, 388
Chloracetyl, 392
Glycyl, 392
Prolyl, 543
Alanyl Alanine, 392
Glycine, 392
Albuminous Substances, 541
Albumins, 666, 670
Acid, 670, 676
Albumoses, 870, 671
, Ethyl, 73, 111, 254
, Methyl, 109
Alburnus lucidus, 588
Alcohol, Acetobutyl, 310
Acids, 306, 356, 538, 548, 598 599, 610 619,
621, 647, 652
Allyl, 123
Amyl, 119, 120, 121
Butyl, 118, 652
Crotonyl, 124
Ethers, 316
Hexadecyl, 122
• Isobutyl, 119
Isopropyl, 117
— — Manufacture of Pure Absolute, 115
of crystallisation, 108, 110, 116
of Fermentation, 120, 164
Oleic, 124
Pinacohyl, 85
Propargyl, 125
Propyl, 117
Alcoholates, 108, 116, 204
Alcoholic Beverages, 114, 342
Fermentation, 112, 426, 492, 526, 681
Alcohols, 98, 114, 362
Acetylene, 125
Chlorine cubstituted, 117, 118
— - conversion of primary into secondary and
tertiary, 108
Dihydric, 306
Diolefine, 125
Higher, 121
Monohydric, 100, 102, 105
— — Olefine, 123
Paraffin, 109
Reactions distinguishing primary, secondary
and tertiary, 109
Saturated, 109, 121
Alcoholysis, 418
Aldehyde, Glycolyl, 203
Acids, 306, 400, 561
Nitrogen derivatives of the, 402, 405,
406
Alcohols, 306, 337, 533, 597, 616, 625
. , Nitrogen, containing- derivatives of
the, 339
Aldehyde-ammonia, 117, 195, 199, 212, 329,
339, 388, 443, 450, 451
• Bisulphites, 207
~ — Chloride, 206
Cyanhydrin, 207, 37 »
• Dihalides, 206
— — Halohydrins, 205
Derivatives, 206
— Hydrazones, 213
Ketones, 306, 343, ««> 536
Nitrogen Derivatives, 353, 354, 355, 35O
Aldehyde Resin, 200
Sulphoxylates, 207
Aldehydes, 100, 103, 106, 124, 189, 235
Acetylene, 215
Acyl, 343
Aldoximes, 196
Dihalogen, 205
Diolefine, 215
Disulphonic Acids of the 210
Halogen Substitution Products of the
Saturated, 201
— — Hydrazones, 196
Hydroxysulphonic Acids of the, 210
Nitrogen Derivatives of the, 210
of the Saturated series, 191
Olefine, 214
Ozonides of the, 204
1 Peroxides of the 203
Sulphur Derivatives of the Saturated, 208
Aldehydogalactonic Acid, 652
Aldines, 344
Aldobutyric Acids, 402
Aldol-ammonia, 339
Condensations, 196, 198, 221, 337, 338, 339
Cyamhydrins, 540
Aldo-olefine Carboxylic Acids, 402
Aldols, 214, 388, 339, 349, 631
Aldopentpses, 616
Aldopropionic Acid, 401
Aldotriose Metasaccharopentose, 620
Aldovaleric Acid, 402
Aldoximes, 151, 212
Alkaloids, 164
Alkamines, 328
Alkarsine, 176, 177
Alkelnes, 328
Alkenes, 8p
Alkenyl Dimethyl Acetic Acid, 299
Alkines, 85
Alkoxides, 108
Alkoxyethylene Ether, Homologues of, 139
Alkyl Acetpsuccinic Esters, 568
Acrylic Acids, 298
Amides, 491
Aminopropane diols, 533
Aminoxy-hydrates, 164
Derivatives, 156
Ammonium Alkyl Dithiocarbamates, 469
Arsenic Acid, 176
Arsonium Compounds, 179
Azides, 169
Carbimides, 461
Chlorides, 162
Chlorophosphines, 175
Compounds. See also Parent substances
Cyanacetic Esters, 491
Cyanamides, 472
Cyanates, 461
Cyanides, 247, 278
Derivatives of Antimony, 179
of Bismuth, 179
of Boron, 180
of Cadmium, 187
of Germanium, 181
of Lead, 188
of Mercury, 187
of Silicon, 180
of the Alkali metals, 184
of the Aluminium group, 188
of the Magnesium group, 184
of the Melamines, 473
of Tin, 182
of Zinc, 1 86
Diazo-compounds, 169, 170
Diazoimides, 171
Disulphides, 144
Disulphoxides, 147
Dithiocarbamic Acids, 449
Fumaric Acids, 519
Glucoses, 633
Guanidines, 455
Halides, 93, 131 _
Halides, Magnesium, 185, 274, 319- Set
also Magnesium Alkyl Halides
682
INDEX
Alkyl Hydautolns, 443
Hydrazines, 169
Hydrogen, 129
Hydrosuiphides, 142
— — — Hydroxylamines, 153, 163, 171
Ketones, 341
Isomelamines, 474
Maleic Acids, 518
• Malonic Acids, 489
Diamides of Homologous, 491
Oxalic Acid, Chlorides of, 482
Oxamides, 483
Oxychlorophosphines, 175
Phosphinic Acids, 141, 173, 175
Phosphinic Oxides, 173, 175
Phospho-acids, 173, 174, 175
Phosphonium Compounds, 173
• Pyrotartrimide, 498
Semicarbazides, 447
— — Succinic Acids, 493
Sulphamides, 168
Sulphaminic Acids, 168
Sulphinic Acids, 146, 147
Sulphonic Acids, 146
Sulphorochlorophosphines, 175
Tetrachlorophosphiries, 175
Tatronic Acids, 550
Thiocarbamic Ester, 449
Thiocarbamides, 469
Thiocyanates, 468
• Thionuric Acids, 578
Thionylamines, 167
Thiosulphonic Acids, 146, 47
Uramils, 578
Xanthines, 591
Alkamines, 330
Alkoxyacrylic Acids, 303
Alkoxy-formamidines, 446
Alkylamine Halides, 167
Alkylamines, 156
Halogen, 330
Hydroxethyl, 329
Phosphorous Derivatives of the, 168
Sulphur Derivatives of the, 167
Alkylated Acetyl Acetones, 351
Diamines, 331
Dimalonic Acids, 613
Imines, 334
Malonic Acids, 508
Nitrosates, 345
Nitrosites, 345
Nitrosochlorides, 343
Alkylenes, 79, 80
Alkylene Oxide, 316
Alkylidene Amino-sulphites, 207
Bis-pyroracemic Acids, 503
Bis-tetronic Acids, 545
Alkali Metals, Alkyl Derivatives of the, 184
Alkylogens, 103, 131
Allan toic Acid, 573
Allantom, 573
Allan turic Acid, 573
Allene, 90
Allium saiivum, 144
ursinum, 144
Allocro tonic Acid, 297
Alloergatia, 209, 514
Alloisomerism, 32, 34
Allomucic Acid, 654
Allophanic Acid, 444
Ester, o-Methyl, 446
Allophanamide, 445
Alloxan, 578
Alloxanic Acid, 580
Alloxantin, 580
Alloxazine, 579
Allyl Acetone, 232
Alcohol, 123, 124, 215, 298, 32*
Derivatives, 124, 454
Alcohols, 124
Acetic Acid, 299
Ester, 229
Acetoacetic Ester, 232
Alkyl Ketone, 228, 229
Allyl Bromide, 136
Chloride, 136, 137
Cyanide, 297
Cyanimide, 472
Disulphide, 144
Ether, 129
Ethylene Tricarboxylic Ester saa
Fluoride, 136
Formamide, 239
Halides, 98, 136
Iodide, 136
Mercury, 188
Isothiocyanic Ester, 470
Malonic Acid, 508
Mustard Oil, 123. 137, 144 470
Succinic Acids, 522
Sulphide, 137, 144
Sulphocarbamide, 452
Thiocyanate, 137
Tribromide, 593
Urea, 440, 446
Allylamine, 166
Alkylaminoacrylic Esters .Homologous, 420
Allylene Iodide, 98
Allylenes, 85, 89, 90, 220
Allylin, 531
Almond Oil, 300
Aluminium, Alkoxy derivatives, 117
Carbide, 67, 72
Group, Alkyl derivatives of the metala of
the, 188
Alypin, 533
Amalic Acid, 580
Amide Acids, 162
Chlorides, 281
Amides, 233, 274, 277
Cyclic, 36
Amidines, 281, 282
Amidoacetonitrile, Methylene, 243
Amidoaldehydes, 339
Amidocarbonyl Glycollic Ester, 436
Lactic Ester, 436
Amido-fatty Acids, 381
Amidoformic Acid, 435
Amidoguanidine Chloride, Galactose, 635
Mercaptals, 635
Amidoisethionic Acid, 325
Amidolactic Acid, 363
Amidomalonic Acid, Nitrile of, 241
Amidothioazoles, 451
Amidovalerolactone, 423
Amidoximes, 283
Amidoxime Oxalic Acid, 484
Amidoxalyl Glycocoll, 484
Amidoxyl Acetic Acid, 381
Amidoxyl-fatty Acids, 381
Amidoxyl Nitriles, 213
Amines, 104, 156, 184, 165, 166, 191
Ketoxime, 345
Aminoacetal, 339, 340
Aminoacetaldehyde, 330, 340
Aminoacetamide, 386
Aminoacetic Acid, 385
Ethyl Ester, 386
Aminoacetoacetic Acid, 543
Aminoacetone, 344
Diethyl Sulphone, 344
Aminoacetonitrile, 386
Aminoacetyl Acetone, 536
Amino-acids, 885, 389, 399
Aminoadenine, 589
Aminoadipic Acid, 560
Aminoalanine, 397
Amino-methyl-la?vulinic Acid, 545
Amino-anilido-oxalic Ester, 486
Aminobarbitunc Acid, 578
Aminobiuret, 445
Aminobutanol, 330
Aminobutyric Acetal, 340
Acid, 889,392, 393, 394
Amino-butyro-sulphonic Acid, 54*
Aminobutyryl, 392
Aminocaffeine, 591
Aminocaproic Acid, 299, 889, 394, 393, 631
INDEX
683
Amiuocaprylic Acid, 390
Aminocarboxylic Acids, 393
Carbamic Acid Derivatives of the.
436
Cyclic Amides of the, 395
Arainocrotonic Acid Nitrile, 420
Ester, 304, 399, 419
Amino-dialkyl-acetic Acids, 382
Araino-dimt:thyl-acetoacetic Acid, Lactam of,
421
Amino-dimetbyl-acrylic Acid Ester, 399
Amino-diinethyl-succinic imide, 557
Amlnodioxypurines, 589
Aminodioxypyrimidine, 586
Aminodithiocyanuiic Acid, 468
Aminoethyl Alcohol, 329
Ether, 330
Mercaptan Hydrocbloride, 331
Sulphonic Acid, 326
Aminoethylidene Succiuic Ester, 568
Ammo-fatty Acids, 381
Aminofumaric Ester, 566
Amino-forniimido-ethers, 446
Aminotumaramide, Ester, 566
Aminoglucoheptouic Acids, 651
Aminoglutaconic Ester, 569
Aminogiutaconimide, 569
Aminoglutaramic Arid, 559
Ij Aminoglutaric Acid, 558, 559, 560
I Aminoguanidine, 458
I Amino-6-guanidino-valeric Acid, 543
Chloride, d-Dextrose, 634
Aminoheptyhc Acid, 396
Aminohydantoic Ester, 447
Aminohydantoin, 447
"i Aminohydantoin Carboxylic Acid, 584
Aminohydracrylic Acid, 540
i Amino-hydroxy-butyric Acid, 541
i Amino-hydroxy-propipnic Acid, 540
, Amino-hydroxy-valeric Acid, 541; Dipeptide
Anhydride, 541
i Amino-imino-metbyl Cyanotriazene, 459
Aminoisethionic Acid, 326, 331
^minoisobutyric Acid, 230, 389
Aminoisosuccinic Acid, 550
; Aminoisovaleric Acid, 393
Aminoketones, 229, 345
iAminolactic Acid, 541
Aldehyde, 534
Aminomalei'c Amide Ester, 566
Amimomaleinimide, 511
iAminomalonamide, 550
Aminomalonic Acid, 549
Aminomalononitrile, 550
Aminomalonyl Urea, 444, 678
Aminomethane Disulphonate, Potassium, 454
Amino-methyl-ethyl Acetic Acid, 389
Aminomethyl Ketones, 244
Sulphurous Ester, 211
Nitrosilic Acid, 459
Aminoraethylene Acetoacetic Ester, 546
Malonic Ester, 561
Aminonane, 165
Amino-octanic Acid, 394
Amino-oenanthic Acid, 390
Amino-olifine Carboxylic Acids, 399
Amino-oxy-pyrimidine, 574
Aminopalmitic Acid, 390
Aminoparaldimine, 212
Aminopentadiene Acid, 399
Aminopentanol, 330
Aminopimelic Acid, 560
Aminopropane Diol, 533
Aminopropanol, 330
\minopropionaldebydes, 340
Acetal, 340
Aminopropionic Acid, 388
Aminopropionitrile, 38"
Aminopropyl Methyl Ketone, 344
Aminopurines, 588, 589
Derivatives, 590
\minopyrotartaric Acid, 556
\mino-sec.-butyl Acetic Acid, 390
Vminostearic Acid, 390
Aminosuccinic Acid, 499, 653
Aminosulpiioual, 344
Amino-tert. -butane Diol, 533
Aminotetrahydroxycaproic Acid, 651
Aminotetrazole, 459
Amiuotetroles, 616
Amiuotetronic Acid, 544
Arninothiolactic Acid, 541
Aminothiopropionic Acid, 376
Aminotic Liquur, 660
Arninotriazoles, 405, 458
Aminoundecaue, 165
Aminouracil, 576
Aminourazole, 448
Aminovaleric Acid, 389, 394
Aldehyde, 340
Aminoxy-hydrates, Tri-alykl, 164
Ammelide, 473
Ammeline, 473
Ammonium Bases, 165, 166
Cyanate, 461
Cyanide, 242
Thiocyanate, 467
Ampelopsis hederacea, 363
Amygdalin, 239, 626
Amyl Acrolein, 215
Alcohol, 119, 120
Acetic Ester of Fermentation, 268
Alcohol of Fermentation, 85, 114, 12 J
Glycerol Diethylin, 532
Glycide Ether, 533
Nitrate, 138
Oxalic Chloride, 483
— — Propiolic Acid, 304
Aldehyde, 216
Amylainine, 164, 165
Amylene, 85
Hydrate, 121
Amylium Nitrosum, 138
Amylodextrin, 663
Amylopectin, 661
Amylose, 662
Amyloxybutyl Bromide, 315 .
Amyloxypropionic Acid, 315, 170
Amylum, 662
Analysis, Elementary organic, 3
Angelic Acid, 292, 898 350
Lactone, 398
Angelica archattgelica .260, 298
roots, 260
Anglyceric Acid, 539
Anhydride of Ethionic Acid, 327
Anhydrides, Acid, 271
Anhydro-euneaheptitol, 625
Anhydroforraaldehyde Urithane, 436
Anhydro-nitrp-acetic Ester, 380
Anhydrotaurine, 327
Anilacetone Dicarboxylic Ester, 569
Anilidobutyrolactam, 498, 514
Anilidodextrose Cyanide, 628
Anilidoperchlorocrotonic Acid, 498
Anilidopyrotartrol actinic Acid, 557
Aniline-acrolein Anil, 347
Anilinocitraconanil, 567
Anilino-dicarboxyl-glutaric Ester, 615
Anilinomaleinanil, 565
Anilinomalonic Acid, 550
Anilinopyrotartaric Acid, 556
Derivatives, 515, 556
Anilinosuccinimide, 498
AnilinotricarbaUylimide Esters, 595
Anilonitroacetone, 231
Anil-pyruvinic Acid, 409
Anil-uvitonic Acid, 409
Animal Fluids, 492
Anthemis nobilis, 298
Anthracene, 96
Antimony, Alkyl derivatives of 179, 184
Antipyrine, 267
Antitartaric Acid, 604
Ants, 236
Apiine, 619
Apionic Acid, 620
Apiose, 819, 630
I
684
INDEX
Apocaffeine, 591
Apples, 551, 663
Aqua amygd alarum amararum, 239
Arabinaminc, 616
Arabinobromal, 618
Arabinochloral, 618
Arabinose, 620, 621, 363, 616, 617, 8l8r 619, 649,
650, 651, 660
Carboxylic Acid, 624, 649, 653
Arabinosimine, 636, 651
Arabitol, 99. 818, 61 8
Arabonic Acid, 597, 618, 619, 820
Arachidic Acid, 261, 262
Arachis hypogcea, 262, 300
Argaricus muscarius, 329
Arginine, 542
Amines, Arsenic, Boron, and Silicon derivative
of Secondary, 168
Aromatic Hydrides, 78
Hydrocarbons, 83
Arrack, 238
Arrhenal, 177, 178
Arrhenius, Electrolytic Dissociation Theory of, 16
Arsenic Acid, Alkyl, 176, 177, 178
Esters of, 141
Alkyl Derivatives of, 175
Oxides, Alkyl, 176
Arsine, Alkyl, 176, 177, 178, 179
Sulphides, 177, 178
Derivatives, 178
Arsenious Acid, Dimethyl, 176
Arsenite, Acetyl, 171
Arsenoxide, Alkyl, 177, 179
Arsonium Compounds, 176, 177, 179
Asparacemic Acid, 553
Asparaginanil, Phenyl, 511
Asparagine. 664, 559, 567
Carboxylic Acid, 612
Aspartic Acids, 499, 668, 567
Aspartyl Aspartic Acid, 555
Dialanine, 556
Asphaltum, 78
Asymmetric Carbon Atoms, 29, 55
Aticonic Acids, 516, 619
Atomic Linking, 21
Volumes, 45
Azaurolic Acid, 284
Azelalc Acid, 300, 506
Aldehyde Acid, 300
Amide. 334
— Dithiolic Acid, 506
Nitrite, 334
Azide, Allophanic Acid, 443
— — Carbamic Acid, 447
Hippuryl, 392
Azides, Acid, 278
Dicarboxylic, 332
Azidoacetic Acid, Hydrazide of, 404
Azidocarbonic Amide, 447
Methyl Ester, 446
Azimethyl Carbonate, 459
Azimethylene, 213
Azine of Glyoxylic Amide, 405
Azinomethane Disulphonate, Potassium, 454
Azocyanacetic Ester, Benzene, 564
Azodicarbamidine, 458
Azodicarbonamide, 447
Azodicarbondiamidine, 458
Azodicarboxylic Acid and Derivatives, 447
Azo-fatty Acids, 397
Azoformamide, 447
Azoformic Acid, 447
Azoic Acid, Methyl, 171
Azo-isobutyromtrile, 397
Azotetrazole, 459
Azoxazoles, 355
Azoxybismethenylamidoxim, 459
Azulmic Acid, 485
Bacillus acidi lacti, 363
— — acidi laevolactici, 364
• boocopricus, 259
Bacillus etkaceticus, 538
• subtilis, 259
tartricus, 341
Bacteria, 381, 652
Bacterium, Sorbose, 341
Bacterium aceti, 256
termo, 313
Barbituric Acid, 444, 574, 578
Barbituryl Imidoalloxan, 581
Bassorin, 663
Beans, 554, 580
Beckmann Change (Inversion, Rearrangement,
Transposition), 160, 227, 300, 571
Beeswax, 122, 262, 260
Beet-Juice, 455, 573, 622
Beet-Root, 387, 39<>, 554, 558, 559, 593, 394,610,
658
Beet Sugar, 121
Behenic Acid, 261, 262
Behenolic Acid, 304, 507
Behenoxylic Acid, 304
Benzal Hydrazine Carbonate, 446
Laevulinic Acids, 422
Semicarbazide, 447
Benzaldehyde, 239
Benzene, 88
Azocyanacetic Ester, 564
Derivatives, 232, 343
Ring, 21
Sulphochloride, 162
Sulphoethoxypyrrolidine, 340
Sulphohydroxamic Acid, 283
sulphone-thipacetoacetic Ester, 543
Sulphuric Acid, 283
Benzene-azo-acetyl Acetone, 537
Benzil, 333
Benzine, 78
Benzotrimethylene, 404
Benzoyl Alanine, 388
Amines, 335
• Amyl Aminomalonic Ester, 393
Cellulose, 665
Glycocoll, 388
Imines, 335
Piperidine, 394
Serine Ester, 540
Triglycyl Glycine, 393
Benzoyl Aminocapronitrile, 395
Benzoyl Aminocaproic Acid Nitrile, 334
Benzylic Acid, Transformation, 342
Berberis vulgaris, 551
Beryllium Alkyls,
Beta vulgaris, 387
Betaine, 165, 33<>, 377, 383, 887, 338
Derivatives, 387, 389
Aldehyde, 340
Bi-iodo-acetacrylic Acid, 423
Bile, 326, 530
Biliary Substances, 676
Bilineurine, 329
Bilirubin, 676
Bioses, 657
Birds, Excrements of, 581
Birotation, 632, 660
Bis-acetoacetic Ester, 546
Derivatives, 484, 610
Bis-acetol Methyl Alcholate, 341
Bis-acetyl Acetone, Methenyl, 598
Bis-aminoguanidine, 458
Bis-aspartic Ester, Hippuryl Aspartyl, 556
Bis-cyanomalonic Ester, 656
Bis-diazoacetamide, 403, 405
Bis-diazoacetic Acid, 405
Bis-diethyl Agimethylene, 228
Bis-dimethyl Azimethylene, 228
Bis-hydrazinocarboxyl, 448
Bis-methyl Alkyl Azimethylenes, 228
Bis-phthalimidomalonic Ester, Alkylene, 606
Bis-pyrazolone Derivatives, 608, 609
Bis-trimethyl Ethylene Nitrosate, 345
Bis-trimethylene Diimine, 337
Tetramethvl Diimonium Chloride. 337
Bismuth, Alkyl Compounds and Derivativesof, 1 7j
INDEX
685
Bisulphites, Aldehyde, 207
Bisulphites, Ketone, 225
Bitter Almonds and Oil, 239
Bituminous Shales, 79, 82
Biuret, 445, 574
Reaction, 392, 445, 66)
Blood Corpuscles, 531, 581, 588
Boghead Coal, Dry Distillation of 71
Boiling Point, 48
• Determination of the molecular weight
from the raising of the, 14; Beckmann's
Method, 15
Boletus edulis, 661
Bombyx processioned, 236
Bone Glue, 673
Oil, 64, 673
Borate, Alkyl, 271
Boric Acid, Esters of, 141
. , Ethyl, 180
Diethyl Ester, Diethyl, 180
Boron, Alkyl Compounds and Derivatives of,
1 80
Derivatives of the Secondary Amines
168
Brain, si 9, J3C, 53-
Br assies, campe&rti, XDZ, 302
rcpa, 3*3
Brassidic Acids, 251. Jol
Brassylic Acid, 301, 507
Bromacetaldehyde, 203
Bromacetic Acids, 288
Bromacetoacetic Esters, 420
Bromacetol, 225
Bromacetonitrile, 388
Bromacetoxime, 345
Bromacetyl Bromide, 97
Bromacetylene, 303
Bromacetyl Urea, 442
Urethane, 436
Bromacrylic Acid, 295
Bromal and Derivatives, 203, 207
Bromallyl Alcohol, 124
Bromamides, 277
Bromanilic Acid, 224
Bromaminocrotonic Est^r, 419
Bromethyl Acctoacetic Ester, 420
Piperidine, 337
Bromethylamine, 331
Bromethylidine Acetone, 349
Bromhydrin, 529
Bromhydrouracil, 574
Bromides, Alkyl, 134, 162
Bromimidocarbonic Ethyl Ester, 446
Bromine, 5
Broraisobutyric Acid, 289
Bromisobutyryl Bromide, 289
Bromisocaproic Ester, 299
Bromisocaproyl Lencine, 392
Pentaglycyl Glycine, 393
Bromisocrotonic Acid, 297
Bromisosuccinic Acid, 491
Bromo-acetoxy-diethyl Acetoacetic Ester, 366
Bromobutyl Methyl Ketones, 225, 343
Bromobutylamine, 331
Bromobutyric Acids, 289, 542
Bromocaffelne, 591
Bromocitraconic Anhydride, 516
Bromocrotonic Acids, 295, 304
Bromo-dimethyl-acetoacetic Ester, 421, 423
Bromo-dimethyl-caproic Ester, 506
-glutaric Ester, 504
Bromoenanthic Acid, 375
Bromo-Ether, 129
Bromo-ethyl-succinic Acid. 298
Bromoform, 94, 203, 235, 246, 408
Bromofumaraldebyde, 347
Bromoglucurolactone, Diacetyl, 652
Bromoglutaric Acids, 297, 560
Ester, 502
Bromoguanine, 588
Bromoisobutyl Aldehyde, 338
Bromoisobutyric Acid, 297
Bromoisopropane, 135
Bromolactic Acid, 368
394
Bromolactose, Hepta-acetyl 660
Bromolasvulinic Acids, 423
Bromomalic Acid, 605
Bromomalonic Dialdehyde 535
Bromometbacrylic Acid, 207, 501
Bromomesaconic Acid, 501, 516
Bromomethyl Amyl Ether 315
Bromomethyl Furfural, 665 -
Bromonitroethane, 151
Bromonitroform, 156, 426
Bromonitromethane, 151, 210
Bromonitropropane, 210
Bromonitropropanol, 344
Bromonitrosobutane, 153
Bromonitrosodimethyl Butane, 153
Bromonitroso-paraffin, 153
Bromonitrosopropane, 153
Bromo-olefine Ketones, 229
Bromopicrin, 152, 156, 426, 421
Bromopropane, 135
Bromopropiolic Acid, 303
Bromopropionyl Urethane, 436
Bromoproprionic Acid, 288, 289
Bromopropylamines, 331
Bromopropyl Malonic Esters,
Methyl Ketones, 343
Phthalimidoraalonic Ester, 543
Bromopyoureide, 443
Bromopyrotartaric Acids, 500
Bromosuccinic Acids, 499, 500
Bromotetronic Acid, 544
Bromotriacetonamine, "2 30
Bromotrinitromethane, 156
Bromoundecylic Acid, 507
Brown Coal, Dry Distillation of, 71, 79
Bunte's Salt, 147
Butadiene Carboxylic Acid, 305
Butallyl Methyl Carbinol, 323
Butane, 76
Dicarboxylic Acetic Acid, 594
Heptacarboxylic Ester, 656
Pentacarboxylic Estrrs, 622
Tetracarboxylic Ester, 613, 614
Tricarboxylic Acid, 593. 504, 595
Butene Lactone Crotolactone, 398
Tetracarboxylic Ester, 615
Butenyl Hydroxy Tricarboxylic Lactone, 6ia
Butter, 259, 262, 530
Butyl, Mercury, 188
Acetylene Acid, 261, 348
Carboxylic Acids, 304
Alcohol of Fermentation, 119, 164
Alcohols, 118, 119, 652
Aldehyde, 118, 201, 215, 314
Carbinols, 120
Chloracetal, 205
Chloral, 118, 195, 203, 534
Acetal, 205
Aldol, 534
Hydrate, 195, 203
Fumaric Acid, 519
Glycerol, 528
Glyoxal, 348
Glyoxime, 354
Isocyanide, 248
Lactic Acid, 365
Malonic Acids, 491
Mustard Oils, 470
Nitramine, 169
Pseudonitrole, 153
Pyrrolidine, 334
Butalanine, 389
Butylamine, 470
Butylamines, 164
Butylene Glycols, 310, 314. 34!
Hydrate. 118
Pentacarboxylic Esters, 622
Butylenes, 82, 118
Butylidene Acetic Acid, 299
Butyramide, 277
Butyric Acid, 258, 259
Derivatives, 289, 402, 406
Fermentation, 363, 365, 259, 6S1
. Ester, Dithioetbyl, 419
686
INDEX
Butyric Esters, 268
Butyrobetaine, Trimethyl, 394
Butyioin, 310, 342
Butyrolactam, 395
Phenyl, 498
Butyrolactone, 289, 373, 874, 497
Derivatives, 374, 375, 398, 495
Carboxylic Acids, 550, 551
Dicarboxylic Ester, Dimethyl, 612
Butyrone Oxime, 227
Butyronitrile, 280
Butyryl Acetoacetic Methyl Ester, 419
Cyanide, 409
Formic Acid, 408
Halides, 271
Butyryl Isobutyl Acetic Ester, 548
Pyroracemic Ester, 547
Butyryl Glutaric Acid, 570
Cacao Butter, 262
Cacodyl, 176, 178, 179
Derivatives, 177, 178
Oxide, 176, 177, 178
Cacodylic Acid, 176, 178
Cadaverine, 331, 334, 542
Cadet's fuming arsenical liquid, 176
Cadmium, Alkyl Derivatives of, 187
Caffeidine, 591
Carboxylic Acid, 591
Caffeine, 387, 572, 590
Derivatives, 591
Caffolin, 591
Caff uric Acid, 591
Calcium Carbide, 67, 88, 97
Cyanamide, 457, 471
Ethoxide, 117
Ethyl Iodide, 186
Malcite, Fermentation of. 491
Calculi, 480, 588
Camomile Oil, Roman, 120
Campholinc Acid, 424
Camphor, 495, 594, 652
Camphoric Acid, 493, 495
Canxphoronic Acid, 495, 594
Camphorphorone, 229, 502
Canarine, 468
Candles, 264, 527
Cane Sugar. See Sucrose
Inversion of, 266
Cannel Coal, Dry Distillation of, 71
Caoutchouc, 91
Capric Acid, 261, 262, 301
Ester, 268
Aldehyde, 201
Caprilonitrile, 281
Caprinone, 223
Caproic Acid, 261
Caprom, 310
Caprolactam, and Derivatives, 396
Caprolactones, 374, 375, 557, 620
Derivatives, 560, 607
Capronamide, 278
Caprone, 223
Capronoln, 314, 842
Caproyl Acetoacetic Ester, 548
Chloride, 271
Caprinamide, 278
Caprylamine, 278
Caprylic Acid, 122, 281
Capryl Ketoxime, 227
Ca pry lone, 223
Caramel, 659
Carbamic Acid, 435
Derivatives, 436, 437, 445, 447
Esters, 428
Sulphur-containing Derivatives of, 448
Azide, 447
Ethyl Ester, Methyl, 436
Hydraride, 447
Carbamide, Dioxalacetic Ester, 568
Carbamide Imidazide, 458
Oxime, 448
Carbamides, 438
Carbamidocyanotriazene, 447
Carbamido-ethyl Alcohol, 440
Carbamidohvdrazoacetic Ester, 447
Carftamido-malpnyl-urea, 578
Carbamidopropionate, 443
Carbamme-thiolic Acid, 448
Carbamino-carboxylic Acid, 383
Carbamyl Thiocarbamyl Hydrazine, 454
Carbazide, 447
Carbazone, Acetoacetic Ester, 447
Carbimides, Alkyl, 461, 464
of Aldehydo- and Keto-monocarboxylic
Acids, 572
of Dicarboxylic Acids, 575
Carbimidoisobutyric Acid, 443
Carbiminodiacetic Acid, 462
Carbinol, zor, 109
Carbinolates 204
Carbithionic Acids. See Dithionic Acids
Carbodiazide, 447
Carbodiimide, 471
Derivative, 472
Carbodimethyl Methene, 475
Carboethyl Methene, 475
Carboethylidene, 475
Carbohydrates, 656
Carbohydrazides, 447, 448
Carbohydrazidine, 486
Carboisopropylene, 475
Carbolthionic Acids, 273
Carbomethane, 475
Carboxylic Ester, Acetal of 489
Carbomethenes, 474
Carbomethoxy Glycine, 437
Carbomethoxy-/3-amidopropionic Ester, 498
Carbomethyl Methane, 475
Carbon Compounds — Constitution Early
theories ; dualistic theory of Berzelius ;
chemical-radical theory ; unitary theory ;
equivalent, atom, and molecule, 18 ; theory of
Gerhardt, 19 ; recent views, 20 ; theory of
atomic linking, or the structural theory, 21 ;
recent views, 27 ; nomenclature, 42 ; physical
properties ; crystalline form 43
Classification of, 68
Carbon, Determination of, 3
Dicarbonyl, 488
Dioxide, 67, 114, 237, 238, 256, 425, 462,
481
Disulphide, 67, 219, 481, 433
Monosulphide, 247
Monoxide, 63, 64, 67, 236, 237, 847, 256,
426, 481
Cleavage, 566
Potassium, 247
Oxychloride, 430
Oxysulphide, 431
Suboxide, 236, 475, 488
Tetrabromide, 426, 429
Tetrachloride, 71, 95, 288. 426, 428
Tetrafluoride, 66, 94, 426, 428
Tetraiodide, 426, 429
Carbonate, Benzalhydrazine, 446
Carbon-dithiolic Acid, 432
Carbonic Acid, Amide Derivatives of 435
Chlorides of, 430
Esters, of, 427
Guaneides of, 457
Hydrazine-, Az'ine- . and Azido-deriva-
tives of, 446
Hydroxylamine Derivatives of. 448
Sulphur Derivatives of Ordinary, 431
Derivatives, 425
Carbonyl, Iron, 247
Bromide, 431
Chloride, 430
Diacetoacetic Ester, 621
Dimethyl Urea, 445
Dithioacetic Acid, 434
— Diurea, 445
• Diurethane, 445
Nickel, 247
Carbopropylidcne, 475
Carbothiacetonine, 452
INDEX
687
Carbothialdine, 450
Carbothiolic Acids, 273
Esters, 274
Carbovalerolactonic Acids, 551, 559
Carbovalerolactamic Acid Nitrile 550
Carboxalkyl Sulphocarbamide, 453
Carboxethyl Acetoacetic Ester, 419
Alanine, 437
Glycine, 437
• Glycyl Glycine Ester, 437
Hydroxycrotonic Ester, 419
Isocyanate, 445, 463
Oxalacetic Ester, 612
Thiocarbimide, 471
Carboxygalactonic Acid, 652, 655
Carboxyl Cyanides, 409
Dimethyl Acrylic Acid, 571
Carboxylic Acids, 100, 232, 392
Alkyl Sulphide, 376
Hydroxysulphine, 377
Mercaptal, 376
Mercaptol, 376
Saturated, 207, 476, 592, 613. 656
Sulphone, 377
Unsaturated, 290, 507, 594, 615, 622
Carboxytartronic Acid, 607
Carbyl Sulphate, 82, 326, 827
Carbylamines, 158, 163, 236, 241, 242, 247, 276
Carbyloxime, 248
Carica papaya, 677
Carnauba Wax, 269
Carnaubic Acid, 677
Carnine, 592
Carob Tree, 259
Caronic Acids, 504
Carotin, 676
Cartilage Gelatin, 673
Casein, 390, 540, 542, 672
Castor Oil, 262, 299, 302, 506
Beans, 264
Catalytic Reactions, 127, 185, 466
Cellobiose, 664
Celluloid, 665
Cellulose, 218, 222, 480, 625, 632, 636, 657, 663,
664
Acetonitrate of 665
Acetyl, 665
Dry Distillation of, 218 223
Formate, 665
Hydrate, 664
Reserve, 631
Sulphite, 664
Ceratonia siliqua, 259
Ceresine, 79
Cerotate, Ceryl, 269
Cerotic Acid, 122, 261 262, 269
Cerotin, 122
Cervical Ligament, 390
Ceryl Alcohol, 122, 262, 269
Certatoe, 269
Cetaceurn, 268
Cetene, 82
C dr aria islandica, 662
Cetyl Alcohol, 82, 122,268
Bromide, 135
Cyanide, 281
Ester, 262
Iodide, 136
Malonic Acid ,491
Cheese, 631
Chelidonic Acid, 482, 561, 570, 621
Chenocholic Acid, 677
Chinese Wax, 122, 262, 269
Chinovine, 619
Chinovose, 619
Chitaric Acid, 650
Chitin, 636
Chitonic Acid, 650
Chitosamine 636
Chitose, 687, 650
Chloracetal, 337, 339
Chloracetaldehyde, 203
Chloracetoacetic Esters, 420
Cbloracetol, 223
Chloracetoxime, 345
Chloracetyl Alanine, 392
Aspartyl Chloride, 556
Carbinol, 534
Cyanoacetic Ester, 607
Digiycyl Glycine, 393
Glycyl Glycine. 392
Urea, 441
Urethane, 436
Chloracetylene, 303
Chloracrylic Acids, 294
Chloral, 118, 201, 204, 239. 368, 429, 534, 652
— Acetyl Acetone, 598
Chloride, 207
Acetone, 842, 425
Alcohate, 204, 369
Aldol, 534
Butyl, 203
Hydrate, 203
Cyanhydrin, 379
Diacetate, 207
Dimethyl Ethyl Carbinolate, 204
Formamide, 239
Hydrate, 195, 202, 204
Hydroxylamine, 213
Oxime, 213
Urethane, 436
Chloralacetamide, 277
Chloral-ammonia, 212
Chloralic Acid, Urobutyl, 652
Chloralide, 202, 294, 368
Chloralides, 369
Chloralimides, 212
Chiorallyl Alcohols, 124
Chloralose, 634
Chloraminocrotonic Ester, 419
Chloranilic Acid, 224, 349
Chlorethane Tricarboxylic Ester, 592
Chlorethers, 129
Chlorethyl Acetate, 323
I Imidoformyl Cyanide, 485
Ketones, 342
Mcthylamines, 331, 335
Sulphonic Acid, 326
Chloride, 326
Chlorethylamine, 331
Chlorhydrins, 84, 319, 368, 520
Chlorides, Alkyl, 134
Amide, 281
Imide, 281
Chlorine, 5
Chloroiodofumaric Acid, 515
Chlorimidocarbonic Ethyl Ester, 446
Chlorisobutyl Methyl Ketone, 225
Chlorisocrotonic Acids, 2yC, 297
Chlorisonitrosoacetone, 409
Chloro-amino-propionic Acid, 541
Chloroamylamine, 331
ChlorobromomaleTc Acid, 515
Chlorobutane Heptacarboxylic Ester, 656
Chlorobutylaldehyde, 203
Chlorobutylamines, 331
Chlorobutyric Acids, 203, 289, 374
Nitrile, 289
Chlorocaffeine, 591
Chlorocarbonic Amide .438
Esfcer, 430
Chlorocarbon-thiolic Ethy Ester, 434
Chlorocasem, 672
Chlorocitramalic Acids, 605
Chlorocitric Acid, 622
Chlorocrotonic Acids, 34. 295, 296, 297, 304, 416
Chlorocyanogen, Solid, 466
Chloro-diraethoxy-propionic Acid, 534
Chlorodithiocarbonic Ethyl Ester, 434
Chlorodithiolactic Acid, 541
Chloroethoxybutane, 319
Chloroform, 72, 94, 222, 235, 245, (29, 510
Acetone, 222
Methyl ,2 84
of Crystallization 245
Chlorofnmaric Acid, 408
Cbloroghitaconic Acid, 620 569
Dialdehyde, 347
688
INDEX
Chloroglutarie Acid, 502, 559
Chloroguanine, 588, 589
Chloroheptylaraine, 331
Cblorohexylamine, 331
Chlorohydracrylic Acid, 539
Chlorohydroxybutycic Ester, 420
CbJorohydroxyisobutyric Acid Nitrile.. 379
Chlorohydroxyisovaleric Acid, 540
Chlorohydroxyprppionacetal, 534
Cbloroiodofumaric Acid, 515
Chloroke tones and Derivatives. 228, 540
Chloroketostearic Acid, 424
Chlorolactic Acid, 388, 532, 539
Chlorolactone, Hepta-acetyl, 660
Chloromalic Acid, and Ester, 603, 605
Chloromalonic Dialdehydc, 535
Chloromaltose, Heptacetyl, 661
Chloromethyl Ether, 127
Furfural. 665
Chloronitrobutanol, 344
Chloronitroe thane, 151
Chloronitromethane, 151
Chloronitropropane, 153
Chloronitropropanol, 344
Chloronitrosoethane, 153. 213
Chloronitrosoparaffin, 152
Chloronitrosopropane, 153
Chlorophenylhydrazido-acetic Ester, 486
Chlorophosphines, Alkyl, 175
Chlorophyll, 674
Chlorophyllan, 675
Chloropicrin, 152, 164, 247, 426, 429
Chloropropiolic Acid, 303
Chloropropionacetal, 338
Chloropropionaldehyde, 215
Acetal,2i5
Chloropropionic Acids 203, 288 ,320
Aldehyde, 203
Chloropropyl Dimethylamine, 331, 337
Alcohol, 319
Chloropyrotartaric Acids, 500
Chlorosuccinic Acid, and Ester, 499 612, 622
Chlorosulphone Acetyl Chloride, 377
Chlorotheophylline, 590
Chlorothioncarbonic Ethyl Ester, 434
Chlorovalerolactone, 423, 599
Carboxylic Ester, 599
Chloroxalethyline, 484
Chloroxalomethyline, 484
Chloroxethose, 129
Chloroximido-acetic Ester, 486
Cholalic Acid, 676
Cholestene, 677
Cholesterol, 676
Cholestrophane, 575
Cholic Acid, 326
Choline, 329, 387, 530, 531
Chondrltin, 672
Chondroglucoprotems 672
Chortosterol, 677
Chromate, Acetyl, 271
Chromopseudomerism, 41
Chrysean, 486
Cinchomeronic Acid, 6ia
Cinchona, 619
Cinchonic Acid, 57*. •«
Cinene, 91
Cineolic Acid, 606
Anhydride, 232
Cistrans Crotonic Acid, 297
Citrabromopyrotartaric Acid, 500
Citracetic Acid, 595
Citrachloiopyrotartaric Acid, 297, 500
Citraconanil , 516
Citraconanilic Acid, 516
Citraconic Acid, 34, 78, 89, 407, 515. 516
Alkyl, 408, 518
Anhydrides, 616, 518, 611
Citradibroraopyroracemic Acid, 297
Citradibromopyrotartaric Acid, 501
Citral, 215, 232
Citramalic Acid, 556
Citramide, 6n
Citrazinic Acid 595, 611
Citric Acid, Dry Distillation of, 218
Fermentation, 631
Acids, 222, 247, 516 .568, 610, 611
Citromycetes glaber, 610
Citromycetes pfefferianus, 610
Citronellal, 215
Acetal, 402
Classification of the Carbon Compounds, 68
Coagulated Proteins, 669
Coal, Dry Distillation of, 71, 79
Coca Alkaloids, 542
Coccus ceriferus, 269
Cochlearia officincilis, 164, 470
Cocoa Beans, 589, 590
Cocoanut Oil, 261, 262, 264
Cod-liver Oil, 300
Coffee Tree, 590
Coffeme, 590
Collidine, 215, 339
Colour, 51
Combination of Carbon with other Elements, the
Direct, 65
Combustion, Heat of, 60
Common centaury, 363
Condensation Reactions, 197
Conductivity, Electric, 58
Coniferin, 626
Coniine, 424
Convicin, 580
Convolvulin, 260 ,619
Conylene, 90
Copper Fulminate, 250
Coprin, 344
Cork, 506
Corn-cobs, 619
Cotton Seed Meal, 661
Seeds, 387
Cotton-wool, 657, 664
Coumalic Acid, 399, 401, 405, 561
Coumalin, 399
Cranberries, 610
Cream of Tartar, 603
Creatine, 164, 387, 455, 456
Creatinine, 456
Crtmor tartari, 603
Cresotic Acids, -o, m-, and p-, 506
Crossulacca, 551
Croton Oil, 259
Croton tiglium, 298
Crotonal-ammonia, 215
Crotonaldehyde, 203, 215, 312, 338, 561
Cyanhydrin, 397
Crotonic Acids, 34, 215, 292, 295, 296, 379, 40^
Acid, Thioethyl, 419
Anilide, 298
Crotonyl Alcohol, 124
Peroxide, 296
Crotonylene, 89
Crystal-lens Globulin, 670
Crystalline Liquid, 47
Crystallites, 541
Cucumbers, Pickled, 362
Cumin, Roman Oi of, 298
Curare, 344
Currants, 610, 663
Curtius Biuret Base, 392
Cyamelide, 438, 460, 461
Cyanacetaldehyde, 354, 401
Cyanacetamide, 443, 489
Cyanacetic Ester, Acetyl, 564
Cyanacetoacetic Esters, 564, 570
Cyanacetone, 354, 419
Cyanacetyl Acetone, 547, 564, 599
Urea, 576, 586
Hydrazide, 489
Acid, 268, 489
Cyanaconitic Ester, 615
Cyanamide, 439, 451, 453. 455, 458, 471
Cyanarmdodicarboxylic, Acid, 445
Cyanariiline, 486
Cyanacetone Dicarboxylic Ester, 612
Cyanacetyl Dimethyl Urea, 590
Cyanamidodithiocarbonic Acid, 467
Cyanammonium Bromide, Trialkyl, 473
INDEX
689
Cyanethenylamidoxime, 489
Cyanethines, 280
Cyanetholines, 461
Cyanhydrins, 197, 221, 240, 37S
Cyanic Acid, 249, 460
Salts, 461
Cyanides, 241
, Alkyl, 278
Cyanimidocarbonic Acid Ethers, 485
Cyanimidodicarbonic Ester, 445
Cyaniraidodiisosuccinic Ester, 488
Cyanimidomethyl Acetyl Acetone .350
Cyanisonitrosoacetamide, 251
Cyanisonitrosoacetohydroxamic Acid. 244
Cyanacetic Ester, Chloracetyl .607
Cyanaconitic Ester, 615
Cyanocarbonic Esters, 483, 484
Cyanodiamylamine, 472
Cyano-dimethyl-acetoacetic Ester, 559, 570
Glutaconic Ester, 521
Cyanodimetbylamine, 472
Cyanodipropylamine, 472
Cyanoform, 592
Cyanoforrnic Esters, 405, 484
Cyanogen (Dicyanogen), 64, 239, 241 485,
488
Bromide, 64, 465
Chloride, 250 465
Iodide, 465
Sulphides, 467, 468
Sulphur Compounds of, 466
Triselenide, 467
Cyanoglataric Esters, 593
Cyanoguanidine, 457
Cyano-isopropyl-glutaric Mono-ester, 503
Cyano-keto-pyrrolidone, 607
Cyanomalonic Ester, 592
Cyanomethazonic Acid, 380
Cyano-methyl-glutaconic Ester, 521
Cyanopropionacctal, 340, 402
Cyanopropionic Ester, 491, 495, 503
Cyanopropyl Phthalimidomalonic Ester, 560
Cyanorthoformic Ester, 485
Cyanosuccinic Ester, Methyl, 592
Cyano-tetramethyl-glutaric Ester, 504
Cyanothioformamide, 486
Cyanotriazene, Amino-imino-methyl, 459
Cyanotricarballylic Ester, Dimethyl, 614
Cyano-trimethyl-glutaric Ester .504
Cyanourea, 445
Cyanoximidobutyric Acid, 546, 568
Cyanuramine Chloride, 474
Dichloride, 474
Hydrides, 474-
Cyanuraminoethylamine Chloride, 474
Cyanurate, Tri-sodium, 461
Cyanurodiamine Monochloride, 474
Cyanuroethylamine Dichloride, 474
Cyanuromethylamine Dichloride, 474
Cyanuramide, 473
Cyanuric Acid, 445, 463, 582
, Amides of, 473
Cyanuromethylamine-ethylamine Chloride, 474
Cyanuric Acid, Dimethyl, 464
Bromide, 466
Chloride, 466, 471, 473
Halides, 465
Iodide, 466
Triacetate, 465
Tricarbonic Ester, 465
Triurea, 465
Cyclic Esters, 371
Sulphinates, 377
Cyclodiacetone Peroxide, 224
Cycloketones, 504
Carboxylic Acids, 505
Derivatives, 221, 250
Cycloparaffins, 80
Carboxylic Acids, 506, 613, 614
Cyclopentene Aldehyde, 348
Ozonide, 402
Cyclotriacetone Peroxide, 224
<>steine, 376, 641
Cystemic Acid, 541
VOL. I.
Cystine, 390, 540, 541, 667
, Diglycl, 543
Cystinuria, 333, 54
Cytosine, 573, 674, 673
Daucus carota, 676
Decane Dicarboxylic Acid, 322 507
Decamethylene Diamine, n <
Glycol, 315
Imines, 335
Decenyl Glycerol Dimethylin, 532
Decyl Alcohol, 107
Decylic Acid, 262
Decylenic Acid, 299
Dehydracetic Acid, 270, 417, 475, 599
Derivatives, 569, 599
Dehydrochloralimides, 212
Dehydromucic Acid, 653, 654
Dehydro-undecylenic Acid, S99. 304
Dekamethylene Diamine, 334
Density, 45
Desmotropy, 38
Desoxalic Acid, 621
Desoxycaffeine, 588, 591
Desoxyfulminuric Acid, 251, 564
Desoxyguanine, 588
Desoxyheteroxanthine, 588, 680
Desoxyparaxanthine, 588
Desoxytheobromine, 589
Desoxytheophylline, 588
Desoxyxanthine, 588
Determination of Carbon, 3
of Hydrogen, 3
of Nitrogen, 6 ; Dumas' method, 6;
Kjeldahl's method, 8 ; Will and Varrentrap's
method, 7
of Phosphorus, 8
of Sulphur, 8
of the Halogens, 8
of the Molecular Weight by the Chemical
method, 10 ; from the vapour density, n ;
Victor Meyer's method, 12 ; of substances
when in solution, 13 ; by means of Osmotic
Pressure, 13 ; plasmolytic method, 13 ; from
the lowering of the vapour pressure or the
raising of the boiling-point, 14 ; Beckmann's
method, 15 ; from the depression of the
freezing-point, 15; Beckmann's method, 17;
Eykmann's method, 17
Dextrin, 113, 625, 632, 649, 660, 661, 668, 664
Dcxtro-compounds. See Gluco-compounds
Dextroheptose, 637
Dextrolactic Acid. 364
Dextronic Acid, 649
Dcxtrosamine, 636
Dextrosaminic Acid, 636, 637
Dextrosaminoxime, 637
Dextrosazone, 629, 633
Dextrose, 113, 341, 363, 534. 620. 623, 624,^30,
632, 636, 649, 653, 660, 662, 663
-Acetone Compounds, 634
Anilide, 628
Benzyl Mercaptal, 634
Carboxylic Acid, 651
Substituted, 633, 634
Dextrosinaine, 636
Dextrosone, 633
Dextroso-oxime, 634
Dextrotartaric Acid, 603
Diacetic Acid, Malonic, 614
Sulphone, 377
Ester, Dibromacetone, 571
Succinic Ester, 351
Diacetin, 530
Diacetoacetic Ester, 547
Diacetoadipic Acid, 609
Diacetobutyric Methyl Ester, 548
Diaceto-dimethyl-pimelic Acid, 610
Diacetofumaric Acid, 610
Diacetoglutaric Acids, Esters, 609
Diacetobydrazine sym., 278
Diacetoisobutyric Ester, 548
Diacetonamine deriv \tives of, 230
2 Y
6go
INDEX
Diacetone, Adonitol, 616
Arabinose, 618
Alcohol, 230, 842
Alkamine, 330
Arabitol, 616
Dextrose, 634
Dulcitol, 624
Hydroxylamine, 281, 342
• Oxalyl, 597
Diacetopropionic Esters, 548
Diacetosuccinic Acid, 609
Diacetoxymalonic Ester, 563
Diacetyl Acetoacetic Ester, 355, 599
Acetone, 537
Acetylhydrazone, 355
Aldol of, 597
• Bromoglucurolactone, 652
Butane, 352
Creatine, 456
Cyanide, 409, 550
Diaminosuccinic Diethyl Ester, 605
Diammovaieric Ester, 655
Dihydroxyacetic Acid, 400
Dihydroxymaletc Acid, 606
Diiminoadipic Ester, 417, 659
Diketoadipic Acid 655
Dioxime, 354
Isosaccharic Ester, 655
Mannosaccharolactone, 653
Mesotartaronitrile, 605
Orthonitric Acid, 156 271
Osazones, 356
Pentane, 352
Pentane Dioxime, 355
Propane, 352
Pyroracemic Acid, 599
Racemic Anhydride, 602
Semicarbazone, 355
' Succinic Acid, 609
Tartanc Acid aud Derivatives, 602, 604
Anhydride, 565 604
Urea, 442
Diacetylene Carboxylic Acids, 523
Glycol, 316
Ethane, 351
Ethylene Diamine, 333
Glutaric Ester, 352
Peroxide, 273
Diacetylenes, 91
Diacetylhydrazone, 355
Diacipiperazine, 391, 892, 541, 543
Diacetamide, 555
Diacetic Ester, 555
Dialanine, Aspartyl, 556
Dialdan, 338
Dialdehydes, 306, 346
Nitrogen-containing derivatives of the, 353
Dialkyl Acetic Acids. Ureides of the 442
Arsine Derivatives, 177
Ethyl Esters, 366
Glutaric Acids, 502
HydantoTns, 443
Hydrazines, 169
Hydroxy- Acids, 369
Nitramines, 169, 170
Peroxides, 129
Phosphinic Acids, 174
Pyrrodiazoles, 278
' Sulphocarbamic Chlorides, 434
Thiocarbamic Acid Chloride, 450
Thiodiazoles, 278
Ureas, 170, 440
Dialkylamlne Sulphonic Acid, 159
— — Oxychlorophosphines, 168
Dialkyl amino-acetonitriles 388
Dialkylamino-acrylic Esters, 420
Dialkylaminochlorophosphines, 168
Dialkylaminosulphochlorophosphines, 168
Dlalkylene Diimlnes, 336
Diallyl, 91, 597
Acetic Acid, 306
— — Acetone, 223, 882, 333
-•• Butyrolactone, 399
— — Carbinolc, 125
Diallyl Malonic Acid, 522 599
Suiphocarbam'de, 452"
Tetra bromide, 91
Ureas, 440
Diallylin, 531
Dialuramide, 578
Dialuric Acid, 444, 577
Diaraide, 169
Diamido-oxalic Ethers, 486
Diamidopyrazole, 489
Diamines, 155
Diaminoacetic Acid, 402
Diaminoadipic Acid. 606
Diaminoazelaic Acid, 606
Diaminobutyric Acids, 542
Diaminobutane, 833
Diaminocaproic Acids, 305, 334, 542
Diaminodiethyl Sulphone, 331
Diaminoethyl Disulphide Hydrochloride, 331
Ether, 330
Diaminoguanidine, 459
Diaminohexanes, 333, 334
Diaminohydrocyanuric Acid, 474
Diaminomalonamide, 563
Diaminononane, 334
Diaminooctane, 334
Diaminopentaues,333, 334
Diaminopimelic Acid, 606
Diaminopropanol, 533
Diaminopropionic Acid, 542
Diaminopropionyl Diaminopropionic Ester, 542
Diaminopyrimidine, 584
Diaminosebacic Acid, 334, 606
Diaminosuberic Acids, 334, 606
Diaminosuccinic Acid, 605
Diaminosulphonal, 331
Diamino-trihydroxy-dodecanoic Acid, 672
Diaminouracil, i, 3, 586, 588, 590, 591
Diaminovaleric Acid 542
Diamylene, 83
Dianilido-oxalic Ether, 486
Dianilinomalonic Ester, 563
Dianilinonitropropane, 533
Dianilmo-propanol, 533
Dianilinosuccinic Ester, 605
Diarsine, Tetralkyl, 176
Diastase, 113, 658, 660, 661, 663, 677
Malt, 660
Pancreas, 658
Diazoacetic Acid and Ester, 169, 402, 419, 509
Diazoacetoacetic Ester Anhydride, 543
Diazoacetyl Glycinamide, 404
Glycine Ester, 403
Glycyl Glycine, 403
Diazoaminomethane, 169, 171
Diazobenzene Sulphonic Acid, 194
Diazocaffeine, 591
Diazomino-paramns, 169, 171
Diazo Compounds, Alkyl, 170
Diazoethane Sulphonate, Potassium, t-?*
Diazoethoxane, 138
Diazoguanidine Cyamide, 459
Diazoimides, Alkyl, 171
Diazoisoraproic Ester, 410
Diazornethane, 167, 169, 197, 213, 418, jwo
Disulphonate, Potassium, 454
Diazoparaffins, 213
Diazopiperizine, 543
Diazopropionic Esters, 410
Diazosuccinamide Methyl Ester, sftjr
Diazosucoinic Ester, 567, 605
Diazotetronic Anhydride, 545
Dibarbituryl Methylamine, 578
Dibenzal, Pentaerythritol, 597
Carbohydrazide, 447
Carbohydrazidine, 486
Diaminoguanidine, 459
Dulcitol, 624
Dibenzoyl Ethane, 495
Ethylene Diamine, 322
Dibromacetaldehyde, 87, 208, 347
Dibromacetic Acid, 888, 509
Dibromacetoacetic Esters, 420, 544
Dibromacetone, 348
INDEX
691
Dibromacetone Diacetic Ester, 571
Dibromacetyl Bromide, 97, 288
Dibromaciylic Acids, 295, 425
Dibromadipic Acids, 606
Dibromethyl Ketol, 536
Dibromhydrins, 529
Dibromisobutyric Acid, 297
Dibromisoheptoic Acid, 423
Dibromobarbituric Acid, 576, 579
Dibromobutane, 323
Dibromobutene Lactones, 398
Dibromobutyl Ketone, 225
Dibromobutyric Acids, 289, 296, 297
Dibromobutyronitrile, 297
Dibromocrotonic Acid, 297, 304
Dibromodiacetyl, 349
Dibromodiethylamine, 331
Dibromofluoracetic Acid, 288
Dibromoglutaric Acids, 502
Dibroraoglyoxime Peroxide, 250
Dibromohexane, 323
Dibromoketones, 225
Dibromolaevultnic Acid, 423
Dibromomaleic Acid, 615, 606
Dialdehyde, 347
Dibromomalonic Acid and Derivatives, 489
Dibromomalonyl Urea, 579
Dibromomethane Diethyl Sulphone, 434
Methyl Ethyl, 225
Dibromomethyl Ether, 207
Dibromonitroacetonitrile, 250
Dibromonitromethane, 151, 247
Dibromopentanes, 90, 321, 323
Dibromofumaric Acid, 515
Dibromopimelic Acid, 506
Dibromopropionic Acids, 215, 289, 294, 318
Dibromopropylene, 90, 124
Dibroraopyrotartaric Acids, 501
Dibromopyruyic Acid, 408
Dibromostearic Acids, 301
Dibromosuccinic Acid, 500, 508, 566, 604
Aldehyde, 347
Dibromotetronic Acid, 544
Dibutyryl, 815, 349
Dicaproyl, 350
Dicarboxyaconitic Pentamethyl Ester, 622
Dicarboxycyclohexenone Acetic Ester, 520
Dicarboxyglutaconic Ester, 561, 616
Dicarboxyglutaric Ester, 613
Dicarboxylic Acids, 306, 310, 373, 515
Sulphur Derivatives, 376, 377
Azides, 332
Oxides, Higher Keton«, 570
Dicarboxy-methyl-tricarballylic Ester, 622
Dicarboxytricarboxylic Acids, 622
Dicarboxyvalerolactone, 612
Dichloracetal, 201, 203, 205
Dichloracetaldehyde, 87, 203, 347, 368
Dichloracetic Acid, 287, 509
Dichloracetoacetic Esters, 224, 420
;Dichloracetone, 224, 348, 529, 534i 610
i Dichloracrylic Acids, 295
Dichloradenine, 588
Dichloral Peroxide Hydrate, 204
Dichlorethers, 129, 205, 319, 338
Dichlorethyl Alcohol, 117, 337
Dichlorhydrins, 123, 224. 529
Dichlorisobutyl Ketone, 225
Dichlorisopropyl Alcohol, 338
Dichlorobutene Lactone, 398
Dichlorobutyric Acid, 289. 296
Dichlorocrotonic Acids, 297, 304
Dichlorohydantoln, 442
Dichlorohypoxanthine, 588
Dichloroketones, 225
Dichlorolactic Acid, 368
Dichloromaleic Acid and Derivatives, 514, 606
Dichloromalein Anil and Derivatives, 498, 501,
5i4
— Dianil, 514
Dicliloromalelnimide, Derivatives, 497, 5*4
Dichlororaalonic Acid, 489
Dichloromethane. See Methylene Chloride
Monosulphonic Acid, 247
Dichloromethane, Substituted 225
Dichioromethyl Alcohol, 247
— — Ether, 111, 127, 287
Djchloromethylal, 205
Dichloromouacetin, 530
Dichloromuconic Acid, 522
Dichloronitrosoethane, 153
Dichloropentane, 321. 323
Dichloropinocoline, 348
Dichloropropane, 136 [538
Dichloropropionic Acids, 289/294, 295, 407, 518,
Dichloropropyl Methyl Ketone 89
Dichloropropylene, 124, 203, 215
Dichloropurine, Methyl, 590
Oxy-, 587
Dichlorosuccinic Acid, 500
Dichloroxalic Esters and Derivatives, 482
Dicyanacetoacetic Esters, 564, 608 612
Dicyanacetyl Acetone, 599
Dicyandiamide, 453, 467, 472
Dicyandiamidine, 457
Dicyanisovaleric Ester, 593
Dicyanoacetoacetic Malonic Ester, 655
Dicyano-bis-acetoacetic Ester, 655
Dicyano-bis-acetyl Acetone, 647
Dicyano-bis-malonic Add, 655
Dicyano-diacetyl Acetone. 599
Dicyanogen, 485. See also Cyanogen
Dicyanoglutaconic Ester, 615
Dicyanomalonic Acetoacetic Ester Lactam.
655
Dicyanomalonic Esters, 612
Dicyanopelargonic Ester, 593
Dicyanopropionic Arid and Ester, 379, 593
Dicyanosuccinic Esters, 489, 614
Dielectric Constant, 53
Di-epi-iodohydrin, 533
Diethoxyacetic Acid, 401
Diethoxyacetoacetic Ester, 534, 598
Diethoxyacrylic Ester, 489
Diethoxybutyric Acids and Esters, 348, 349, 412,
Diethoxymalonic Ester, 563
Diethoxymethylal, 205
Diethoxypropionic Acids, 347, 401
Diethoxysuccinic Acid, 566
Diethyl Acetamide, 278
Acetic Acid, 261, 369
Acetonitrile, 280
Acetyl Chloride, 271
Acetylene Glycol Dipropionate, 315
Alloxam, 579
Ally! Carbinol, 124
Aminpacetone, 344
Arninoacetonitrile, 211, 888
Aminomethyl Sodium Sulphite, 211
Aminomethylene Acetate, 211
Arsenic Acid, 1 78
Barbituric Acid, 576, 577
Borine Chloride, 180
Butyrolactone, 876, 495
Carbinol, 119 121
Chloride, Tin, 182
Cyanacetamide, 443
Dinitro-oxamide, 484
Dithiophosphinic Acid, 175
Hydroxybutyric Acid, 371
Ethane Tetracarboxylic Ester 6ij
Ethylene Lactic Acid, 371
Ethylidene Lactic Acid, 366
Formal, 205
Glutaric Acid, 504
Glycidic Ester, 540
Glycocoll, 387
Glycollic Acid Nitrile, 379
Hydantoln, 448, 444
Hydroxides, Thallium, 188
— • — Hydroxylamine, 172
Ketone, 106, 223
— Semicarbaz.one, 228
Magnesium, 184
Malelc Anhydride, 516, 519
Malonic Acid, 491
Acid Nitrite, 491
692
INDEX
Diethyl Malonuric Acids, 577
• Malonyl Thiourea, 577
• Urethane, 577
Methyl Ethylene Nitrosate, 343
Nitramine, 169
Nitrosamine, 168
Oxalic Acid. 366
Oxalyl Acetoacetic Ester, 569
Oxamic Acid, 483
Oxamide, 484
Oxamethane, 483
Oxetone, 535
Oxide, Tin, 182
Peroxide, 130
Pseudouric Acid, 578
Silicon Compounds, 181
Stannic Oxide, 183
Succinic Acids, 494
Sulphate, 138
Sulphite, 141
Sulphocarbamide, 452
Sulphone Dibromomethane, 434
Methyl Ethyl Methane, 226
Tetramethylene Ketone, 503
Tin, 182
Urea Chloride, 438
Ureas, 440
Violuric Acid, 580
Xanthochelidonic Ester, 621
Diethylamine, 165
Diethylamine, Acetic Ethyl Ester, 387
Diethylaminochloroborine, 168
Diethylaminochlorophosphine, 162, 168
Diethylaminochlorosilicine, 162, 168
Die thylaminopropionit rile, 389
Diethylaminosulphochlorophosphino, 1 68
Diethylaminoxychlorophosphiue, 168
Diethylene Diimine, 336
Disulphide, 324, 325
Thetine, 377
Disulphone, 325
Glycol, 813, 316
Diethyleneimide Oxide, 330
Oxide, 312, 318
Sulphone, 324
Tetrasulphide, 325
Diethylbydrazine, Diformyl, 239
, Thionyl, 170
Diethylhydrazines, 170
Diethylin, 531
Difluorethyl Alcohol, 288
Bromide, 288
Difluoracetic Acid, 288
Difomin, 530
Diformacetal, Adonitol, 616
Diformal Peroxide Hydrate, 203
Tartaric Acids, 604
Diformal dehyde, 199
Peroxide Hydrate, 129
Uric Acid, 582
Diformyl, 346
Diethylhydrazine, 239
Hydrazine, 170, 239
Diglutaconic Acid, 520
Diglutaric Acid, 658
Diglycerol, 532
Diglycide, 532
Diglycl Cystine, 543
Diglycocoll, Oxalyl, 484
Diglycollamic Acid, 378
Diglycollamide, 378
Diglycollic Acid, 313, 367, 378
Diglycollide, 367
Diglycollimide, 378
Diglycolyl Diamide, 392
Diglycyl Glycine, 391, 392
Carboxylic Acid, 437
Dihalogen Aldehydes, 205
Propanes, 322
Dihaloid Malonic Acids, 563
Dphalohydrins, 529
Dihydric Alcohols, 307
Dihydrocholesterol, 676
Dihydro-m-xylol, 232
Dihydroresorcinol, 424
Dihydrotetrazine, 405
Dihydroresorcyl Propionic Acid, 571
Dihydrotrimesic Acid, Methyl, 408
Dihydroxyacetic Acid, 400
Dihydroxyacetone Glycerol Ketone, 53 \
Dihydroxyacetyl Dimethyl Acetic Acid Lactone,
546
Dihydroxyadipic Acids, 348, 606
Dihydroxybehenic Acid, 539
Dihydroxy-butyl-methyl Ketone, 534
Dihydroxy butyric Acids, 296, 539
Dihydroxy-dihydro-methyl-heptenone, 53 4
Dihydroxy-dimethyl-acetoacetic Acid Lactone
421
Dihydroxy-dimethyl-glutaric Acid, 606
Dihydroxyethylamine, 328, 330, 388
Dihydroxyethyl Diketopiperazine, 541
Dihydroxyethylene Succinic Acids, 599
Dihydroxyglutaric Acids, 605, 606, 622
Dibydroxyguanidine, 459
azo-body, 459
Dihydroxyiso butyric Acid, 539
Dihydroxyiso-octylic Acid, 339
Dihydroxyketone Dicarboxylic Acids, 621
Dihydroxyketosuccinic Diethyl Ester, 608
Dihydroxymaleic Acid, 337, 606
Dihydroxymalonic Acid, 562
Dihydroxy-olefine Carboxylic Acids, 606
Dihydroxy propane Tricar boxylic Acids, 605, 622
Dihydroxypropionic Acid, 538
Dihydroxypropyl Malonic Acid, 599
Dihydroxypyridine Carboxylic Acid, 6il
Dihydroxypyrirnidine, 573
Dihydroxysebacic Acid, 606
Dihydroxystearic Acids, 301, 539
Dihydroxysuberic Acid, 348, 606
Dihydroxytartaric Acid. 607
Dihydroxytricarboxylic Acids, 621
Dihydroxyundecylic Acid, 539
Dihydroxyvaleric Acid, 539
Dihydroxyvalerolactone, 598
Dihyroracemic Acid, Acetone, 571
Diimide, 447
Diimido-oxalic Ether, 486
Diimido-oxalyl Dimalonic Ester, 488
Diimido-tctra-acetyl Butane, 350
Diiminoadipic Ester, Diacetyl, 655
Diiminobarbituric Acid, 576
Diiminobutane, Tetracetyl, 647
Di-iodbydrin, 529
Di-iodoacetamide, 404
Di-iodoacetic Acid, 288, 404
Di-iodoacetone, 225
Di-iodoacrylic Acids, 295
Di-iodoethers, 129, 320, 330
Di-iodoethylene, 97
Di-iodofumaric Acid, 515
Di-iodomalonic Acid, 489 Ti.S4
Di-iodoraethane Disulphonate, Potassium, 434,
Di-iodomethyl Ether, 207
Diiodopurine, 584
Diisethionic Acid, 326
Diisoamyl Arsenic Acid, 178
Diisoamylarsine Compounds, 178
Diisoamylene, 85
Oxide, 318
Diisobutyl Acetylene Glycol Diisovalerate, 316
Diisobutylaminochloroarsine, 168
Diisobutylaminochloroborine, 168
Diisobutylaminochlorophosphine, 168
Diisobutylaminochlorosilicine, 168
Diisobutylaminosulphochlorophosphine, 168
Diisobutylaminoxychlorophospbine, 168
Diisobutyl Carbylamine, 165
Glycollic Acid 366
Ketone, 223
Diisobutylene, 85
Diisobutyryl, 349
Diisocrotyl Oxide, 318
Diisomtramines, 154
Diisonitrosoacetone, 534, 5S7
Diisonitramines, 210
Diisonitrosobutyric Ester, 547
INDEX
693
Diisonitrosopropionic Acid, 545
Diisonitroso-succinyl-succinic Ester. 567
Diisopropenyl, 91
Diisopropyl Ketone, 223
Oxalic Acid, 366
Sortie Methyl Ketone, 232
Succinic Acid, 494
Diisopropylidene Succinic Acid, 522
Diisovaleryl, 349, 316
Glutaric Acid, 522
Diketoadipic Carboxylic Acids, 655
Diketobehenic Acid, 304
Diketobutane, 349
Diketobutyl Alcohol, 536
Diketobutyric Acid, 546
Diketobutyrolactone Phenylhydrazone, 545
Diketocarboxylic Acids, 546
Peroxide, 547
Diketohexamethylenc, 492
Diketone Dichlorides, 350
Diketones, 306, 348
• Nitrogen-containing derivatives of
— ; — Oximes of, 354
Diketopimelic Acids, 503, 609
Diketostearic Acid, 304
Diketosuccinic Esters, 608
Diketovaleric Acid, 547
Dilactyl Diamide, 393
Dilactylic Acid, 367
Dilaevulinic Acid, 610
Dilituric Acid, 577
Dimalonic Acid, Oxalyl 65 s
— Acids, 613
Dimethoxyacetone, 534
Dimethoxychloropyrimkline, 574
Dimethoxyheptane-4-ol, 532
Dimethoxymethylal, 205
Dimethoxypyrimidme, 574
Dimethyl Acetal, 205
Acetic Acid, 248, 259
Acetoacetic Acid, 420
Acetobutyric Acid, 424
Acetonyl Acetone, 852. 423
Acetone Dicarboxylic Esters, 423, 569
Acetyl Pyrrole, 492
Acrylic Acids, 291, 298
• Adipic Acids, 505
Alloxans, 575, 579, 580
Allyl Acetyl Acetone, 229
Carbinol, 124
Amido-acid, 537
Aminoacetone, 344
Aminobutane, 165
• Aminobutyric Methyl Ester, 394
Angelic Lactone, 399
A'- Angelic Lactone, 398
Arsenious Acid, 176
Arsine, 177
Trichloride, 178
Aticonic Acid, 519
Aziethane, 355
Barbituric Acids, 576, 577
Bishydrazimethylene, 355
Bromide, Thallium, 188
Butane Tricarboxylic Acid, 594
— — Butanonal Acid, 348
Butyrolactam, 396
Butyrolactone Dicarboxylic Ester, 612
Butyrolactones, 374, 620
Carbinol, 117
Chloride, Thallium, 188
Chloromine, 164
Citraconic Anhydride, 518
Coumalic Acid, 571
Coumalin, 399
Cyanamide, 472
Cyanethane Dicarboxylic Ester, 494
Cyanoglutaric Ester, 593
Cyanopropionic Ester, 498
Cyanosuccinic Esters, 498, 593
Cyanuric Acids, 464
Cyclobutanone Carboxylic Ester, 569
Diacetyl Acetone, 537
the,
Dimethyl Diacetyl Pyrazine, 536
; — Racemic Ester, 602
Dibromohexane, 91
Dicyanoglutaric Ester, 504
- Dicyano-methyl Ammonium Bromide,
Diethyl Ammonium Iodide, 166
Dinitroethane, 155
Tetrahydrofurfurane, 318
Dihydroxyadipic Acids, 606
Dihydroxyheptamethylene, 352
Diketone, 349
Ethane Tetracarboxylic Ester 613
Tricarboxylic Ester, 494
Ethoxypyrimidine, 282
Ethyl Acetic Acid, 261
Derivatives, 271, 280
Betames, 387
Carbinol, 83, 119, 120, 121
Ethylene Nitrosochloride, 345
Hydracrylic Acid, 371
Ethylene,
Oxide, 318
Formocarbothialdine, 450
Fumaric Acid, 519
Furazane, 355
Furfurane, 351
Glutacpnic Acids, 521
Glutaric Acids, 503, 504, 521, 593
~~~ — — Bromo-derivatives, 503
Derivative, 424
Ester, 506
Glutolactonic Acid, 521
• Glycidic Acids, 539, 612
Glycocoll, 387
Glyoxal, 349
Glyoxime Peroxide, 355
Hydantolns, 443
Hydracrylic Acid, 370
Hydrazines, 170
Hydroxyglutaric Acids, 560
Hydroxypro picnic Acid, 339
Hypoxanthine, 589
lodamine, 167
Iodide, Thallium, 188
Isopropenyl Acetic Acid, 371
Isopropyl Ethylene Lactic Acid, 371
Fulgenic Acid, 523
Isoxazples, 354, 355
Itaconic Acids, 518
Ketazine, 228
Ketene, 236, 290, 475
Ketol, 841, 342
Ketone, 222
Ketopyrrolidone, 421
Laevulinic Acids, 398, 428
Methyl Ketone, 353
Magnesium, 184
Malei'c Anhydride, 518
Malic Acids, 421, 656
Malonic Acid, 299, 491
Mesaconic Acid, 519
Metbylene Dithioglycollic Acid, 376
Nitramine, 169
Nitrosamine, 168
Phenyl Pyridazolone, 424
Oxalacetic Ester, 567
Oxalic Acid, 365
Oxamic Acid, 161
Oxamide, 161, 484
Oxetone, 225, 585
Oxychloropurine, 590
Parabanic Acid, 575
Paraconic Acid, 518, 558
Pentaglycerol, 528
Phosphinic Acid, 175
Pimelic Acids, 506
Piperidine, 167
Propane Tricarboxylic Esters, .593
Tetracarboxylic Ester, 504
Pseudouric Acid, 578
Pyrazolidine, 355
• Pyridone, 399
Pyrone, 599
Pyroracemic Acid, 408
694
INDEX
Dimethyl Pyrrole, 352
Pyrrolidines, 335, 396
Racemic Acid, 408, 605
Semicarbazide, 447
Sorbic Acids, 305, 306
Methyl Ketone, 232
Stannic Oxide, 183
Succinanil, 498
Succinanilic Acid, 497
Succinic Acids, 494
Derivatives, 494, 496, 499
Esters, 315, 495
Succinimide, 498
Succino-nitrile Acid, 498
Succinyl Chlorides, 423, 485
Sulphate, 138, 158, 164, 166, 171, 266
Sulphite, 140
Sulphurous Ester, 140
Tellurium Oxide, 148
Tetrahydrofurfurane, 318
Tetrahydropyrone Dicarboxylic
621
Tetramethylene Glycols ,315
. Ketone, 503
Oxide, 318
Thetine, 377
Dicarboxylic Acid, 377
Thiosemicarbazide, 454
Thioureas, 452
Triazene, 171
Tricarballylic Acids, 593, 6ia
Trimethylene Glycols, 314
Uracies, 575
Uramil, 578, 580
Urea Chloride, 438
1 Malonyl, 576
Uric Acids, 588, 589, 590
Valerolactones, 375
Vinyl Hydracrylic Acid, 398
Succinic Acid, 520
Xanthines, 588, 589
Oxypurine, 589
Dimethytemine, 159, 165
Carboxylic Esters, 393, 394
Hydroxyethyl, 329
Ethyl Ether, 330
Dimethylaminoacetic Methyl Ester. 387
Diraethylaminoacetomtrile, 387. 388
Dimethylene £-Dihydrazinophenyl, 198
Dulcitol, 624
Galactonic Acid, 650
Glucoheptonic Lactone, 631
Gluconic Acid, 649
Imine, 335
Rhamnitol, 616
Succinic Acid, 522
Dimethyl-hydroxy-pyrozole, 537
Dimethyl-nitroso-hydroxy-urea, 448
2,6-Dimethyl-octane-3-one Acid, 424
Dimethoxysuccinic Acid, 604
Dimyricyl, 76, 77, 122
Dinitroacetic Ester, 402
Dinitroalkylamines, 339
Dinitrobromobenzene, i6a
Dinitrobutane, 155
Dinitrocaproic Acid, 420
Dinitrodiisoamyl, 155
Dinitrodiisobutyl, 155
Dinitroethane, 155
Dinitroethyl Methyl Ether, 156
Dinitroethyiic Acid, 172, 187
Dinitroglycerines, 530
Dinitroglycoluril, 441
Dinitrohexane, 155
Dinibro methane, 155, 156, 339
Dinitro-oxamide, Diethyl, 484
Dinitroparaffins, 154, 210, 219
Dinitropropanes, 165, 259, 333, 380
Dinitrosodiisopropyl Acetone, 231, 535
Dinitrosoisopropyl Acetone, 535
Dintrosopentamethylene Tetramine, 211
Diniitrotartaric Acid, 604
Dinitrotriiodoethylene, 151
Dinitrourea, Ethylene, 441
Ester,
Dinotroethyiic Acid, 172
Dioctyl Acetic Acid, 261
Diolennes, 85, 80, 186
Diozonides, 90, 91
Diolefine Alcohols, 125
Aldehydes, 215
Carboxylic Acids, 303
Ke tones, 228
Lactams, 399
Dioxalic Ester, Acetone, 621
• , Acetonyl Acetone, 655
Dioxalosuccinic Ethyl Ester, 656
Lactone Ethyl Ester, 656
Dioximidosuccinic Acid, 564, 608
Ester, Peroxide of, 405
Dioximidovaleric Acid, 546
Dioxoallene, 488
Dioxopiperazine, 391, 392
Dioxybutyric Acid, 296, 539, 546
Dioxypurine, 588
Amino-derivatives, 589
Dioxypyridine, 520
Dioxypyrimidine, Amino-, 586
Dioxyvaleric Acid, 547
Dipalmitin, 530
Dipentene, 91
Dipentyl Ethylene Glycol, 314
Dipeptides, 390, 391, 403, 542, 543, 671
Dipcptones, 671
Diphenyl Butyrolactone, 495
Diethylene Diamine 336
Dipiperidyl Piperazonium Bromide, 337
Dipivaloyl, 350
Dipropargyl, 91
Dipropionic Acid, u-Sulphone, 377
Acid, Mercury, 289
, Oximidoacetone, 571
Dipropionyl, 315, 349
Cyanide, 408, 550
Dipropyl Acetylene Glycol Dibutyrate, 315
Aminochloroborine, 168
Aminosulphochlorophosphine, 168
Barbituric Acid, 576
Bromide, Thallium, 188
Carboxylic Ester, Ethane, 653
Chloramine, 167
Chloride, Thallium, 188
Ethylene Glycol, 314
Hydroxylamine, 172
Iodide, Thallium, 188
Ketone, 106, 223
Malonic Acid, 419
Malonuric Acid, 577
Nitramine, 169
Succinic Acid, 494
Sulphite, 141
Dipropylaminoxychlorophosphine, 168
Di-£-toluene Sulphotrimethylene Diaimde,
Disaccharides, 657
Disacryl, 215
Disilicon Hexethyl, 181
Dispersion, 52
Distillation, 48
Disuccinic Acid, Methylene, 614
, Trimethylene, 614
Disulphide, 367
Sulphocarboxethyl, 433
Disulphides, Thiuram, 449
Disulphonic Acid, Ethylidene, 210
Hydroxymethane, 247
Methylene, 210
of the Aldehydes, 210
Acetone, 226
Dithioacetic Acid, Carbonyl, 434
Dithioacetone, 226
Dithioacetyl Acetone, 350
Acetyl Acetone, 350
Dithio-bis-malonic Ester, 489
Dithiobiuret, 453
Dithiobutyrolactone, 376
Dithiocarbalkylaminic Acids, 449
Dithiocarbamates, Alkyl, 469
Dithiocarbamic Acid, 449
INDEX
695
Dithlocarbamic Acid, Cyclic Derivatives of,
450
Esters, 450
Dithiocarbamyl Diallylamine, 454
Hydrazine, 454
Dithiocarbazine Acid, 454
Dithiocarbonic Acids, 431, 438
Esters, 449
Ethylene Ester, 344
Dithiocyanic Acid, 467, 468
Dithiocyanoethane, 469
Dithiocyanomethane, 468
Dithiodiethylamine, 162, 167
Dithiodiglycollic Acid. 376
Dithiodilactic Acid, 376
Dithiodimethylamine, 167
Dithiodipropionic Acid, 376
Dithioethyl Butyric Ester, 419
Dimethyl Methane, 226
Dithioglycol, 324
Dithioglycollic Acid, Dimethyl Methylene, 376
Dithiomelanurenic Acid, 468
Dithionic Acids, 273, 274
Dithio-oxamide, 486
Dithiophosphinic Acid, Diethyl, 175
Dithiopropionic Acid, 541
Dithiotetrahydrothiophene Tetracarboxylic Ester,
656
Dithiotetralkyl Diamines, 167
Dithiotetralkylamines, 167
Dithiourazole, 454
Dithiourethanes. 450
Dihydroxypropyl Malonic Acid Lactone, 599
Dipropyl Carbodiimide, 472
Diurea, 448
Carbonyl, 445
Ethylene, 441
Diureldes, 347, 680
Diureldomalonic Acid, 584
Diurethane, Carbonyl, 445
Glyoxylic Acid, 436
Diurethanes, 436
Divinyl, 88, 90, 596
Dodecane, 77
6,7-Dodecane-diol, 310
Dodecyclic Acid, 262
Dry distillation of peat, bituminous shale, brown
coal, coal, boghead, cannel coal, 71
cf tar, 218
of tartaric acid, 256
of wood, 71, 107, no, 218, 222
of wood vinegar, 256
Drying oils, 301
Hemp oil, 302
Linseed oil, 302
Nut oil, 302
Poppy oil, 302
Dulcitol, 112, 601, 684, 627, 635, 654
Duroquinoae, 349, 350
Dyes, 451
Dynamite, 530
EARTH-NUT Oil, 263
Edestin, 670
Egg, Yolk of, 329, 530, 53«
Egg-shells, 541
Elaldic Acid, 292, 801
Elastin, 392
Elayl Chloride, 322
Electric Conductivity, 58
Electrical Absorption, Anamolous, 54
Electricity, Action of, 64
Electrolytic Dissociation, Theory of Arrnemus, 16
Elemi Resin, 677
Empyreumatic Oils, 257
Emulsin, 633, 635. 658, 677
Enneamethylene Glycol, 313
Enzyme, Gastric, 671
Pancreatic, 671
Theory, 112
Enzymes, 113, 658, 660, 666, 677
Epibromohydrin, 533
Epichlorhydrin, 296, 368, 838, 539
Epiethylin, 538, 539
Epihalohydrins, 529
Epihydrin 368
Alcohol, 532
Carboxylic Acid, 539
Ether, 533
Epihydrinic Acid, 539, 368
Epi-iodohydrin, 533
Equisetum fiuviatile, 594
Ergot. 661
Erlenmeyer, Ruie of, 37, 343
Erucic Acid, 292, 801, 507
Erythrene, 90
Erythrin. 596
Erythritol, 90, 99, 118, 596, 604
Derivatives, 596, 597
Erythroca centaurium, 363
Erythrodextrin, 663
Erythroglucic Acid, 598, 536
Erythroglucin, 596
Erythronic Acid, 598
Erythronitrolic Acid Salts, 154
Erythrose, 596, 597, 616, 618, 620
Derivatives, 597, 619
Erythrulpse, 596
Ester Acids, 130
Esters, 108, 125, 130, 263
Acid, 130
Neutral, 130
Ethal, 122
Ethane, 64, 72, 258
Dibenzoyl, 495
DisuJphochloride, 327
Disulphonate, 327
Hexacarboxylic Acid, 656
Hexamethyl, 75, 77
Polyhalide, 95
Tetra-acetyl, 597
Tetracarboxylic Acid, 492, 813, 656
Ester, 488, 656
Tricarboxylic Ester, 492, 502, 613
Ethanoyl Chloride, 270
Ethenyl Amidine, 282
Amidoxime, 283
Tricarboxylic Ester, 592
Trichloride, 284
Ether, Addition Compounds, 127
Derivatives, in, 127
Homologue of Alkoxyethylene, 139
Methyl, 127
Sulphur, 127
Vinyl, and Derivatives, 129
Ethers, 125, 127, 281, 404
Mixed, 129
Monohaloid, 206
Etherates, 127, 185, 207
Ethers of the Glycols, 204, 316
Ethionic Acid, 326
Ethionic Acid Anhydride, 327
Etho-glycollic Ester, Ethyl, 360
Ethoxal Nitrolic Acid, 486
Ethoxaldoxime Chloride, 486
Ethoxyacetaldehyde, 338
Ethoxyacetonitrile, 341, 879
Ethoxyacetyl Acetone, 536
Ethoxyacroleln Acetal, 347
Ethoxyacrylic Acids, 897, 401
Ethoxyaminopropionic Acid, 540
Ethoxy butyric Aldehyde, 338
Ester, 296, 870
Ethoxybutyronitrile, 380
Ethoxycaprylic Ester, 359
Ethoxycro tonic Acids, 898, 418
Ethoxyfumaric Ester, 566
Ethoxyglutaconic Acid, 569
Ethoxyhexyl Iodide, 315
Ethoxy-hydroxy-butyric Acid, 539
Ethoxyisosuccinic Ester, 508
Ethoxyl Chloracetoacetic Ester, 545, 598
. Malonic Acid, 549, 607
Propionic Acid, 366
Ethoxylamine, 172
Ethoxymaleic Acid, 566
Anhydride, 566
696
INDEX
EthoxymaleTc Homologous, 341
Ethoxymethyl Acrylic Acid, 401
Ethoxymethylene Acetal, 347
Acetoacetic Ester, 546
Acetyl Acetone, 536
Ketone, 343
Malonic Ester. 561
Ethoxypyridine, 399
Ethyl, Beryllium, 184
Cadmium, 187
Germanium, 181
Mercury, 188
Zinc, 187
Acetic Acid, 258, 259
Acetoacetic Acid, 355, 418
Amide, 419
Acetobutyric Acid, 424
Acetoglutaric Ester, 570
Acetone Dicarboxylic Ester, 569
Acetopropionic Acid, 375
Acetylene Carboxylic Acid. 304
Acrylic Acid, 298
Adipic Acid, 505
Alcohol, 73, HI, 251, 601
Aldehyde, 199. See Acetaldehyde
Allyl Acetic Acid, 375
Aminovaleric Acid, 394
tert.-Amyl Ketone, 224
Arsenate, 141
Arsenic Acid, 177
Arsenite, 141
Arsine, 177
Aticonic Acid, 520
Borate, 141
Boric Acid, 180
Bromide, 135
Bromomalonic Ester, 491
Butene Lactone, 398
sec.-Butyl Hydroxylamine, 172
Butyrolactones, 3/4
Cacodyl, 176, 178
. Calcium Iodide, 186 ; " etherate," 186
Carbamic Ethyl Ester, 436
Carbamine-thiolic Acid, 448
Carbonic Acid, 427
Carbothiolic Acid, 274
Carbylamine, 248
Chloride, 74, 1", 135
Chlorophosphine, 175
Citraconic Acid, 518
Creatinine, 457
Crotonic Acid, 299
Cyanide, 280
Cyanamide, 472
Diacetamide, 277
Diallyl Acetoacetate, 306
Diazoacetate, 403
Dichloramine, 167
Dichlorhydrin, 529
Dichloroxalic Chloride, 482
Dimethyl Butyrolactone, 375
Trimethylene Glyco!, 314
Disilicate, 141
Ether, 127
Ethane Tetracarboxylic Ester, 613
Etho-glycollic Ester, 360
— Ethylene, 85
Fluoride, 133
Formamide, 239
Fumaric Acid, 420, 518
Glutaric Acids, 502
Glyceric Acid, 539
Glycerol, 528
, Diethyl Ether, 532
, Glycide Ether, 533
Glycocoll, 387
Glycollic Acid, 966
— — Ester, 360, 368, 404, 607
HydantoTns, 443
Hydracrylic Acid, 370
Hydrazine, 170
Hydrogen Peroxide Salt, Barium 3 3
-.. Hydroselenide, 148
Hydroxysorbic Ester, 398
Ethyl Hydroxybutyric Acid, 370
— — Hydroxyl Urea, 448
— — Hydroxylamine, 172
Hydroxythiourea, 454
Hydroxytrichlorobutyric Acid, 557
Hypochlorite, 141
Imidochlorocarbonic Ester, 446
• Iodide, 136
Iodide, Mercury, 188
Isothionate, 326
Isocrotonic Acid, 299
Isocyanide, 248
Itaconic Acids, 518
Ketone, 475
Ketol, 341
Laevulinic Acid, 423
Magnesium Iodide, 185
Male'ic Acids, 518
Malic Acids, 557
Malonic Acid, 491
Mercaptal, Arabinose, 618
Mercaptan, 143, 449
Mercaptochloropyrimidine, 574
Mercuric Hydroxide, 188
Mesaconic Acid, 519
Methyl Acetopropionic Acid, 375
Adipic Acid, 505
Butyrolactones, 375
Glyceric Acid, 539
Ketone Semicarbazone, 228
Valerolactone, 375
Methylamine, 165
Methylene Amine, 211
Mustard Oil, 470
Nitramine, 169
Nitrate. 116, 137, 138
Nitric Ester, 137
• Nitrolic Acid, 154
• Nitrosolic Acid, 284
Nitrous Ester, 138
Oxalacetic Ester, 567, 607
Oxalic Chloride, 482
Oxamic Acid, 483
Oxamino-chloride. 4 83
Oxychlorophosphir.PS, 175
Paraconic Acid, 299, 557
Phosphate, 141
Phosphinic Acid, i75
Phosphite, 141
Piperidone, 396
Propane Tetracarboxylic Ester, 614
Propyl Acetic Acid, 261
. Ketone, 106
Selenide, 148
Selenite, 148
Silicates, 141
Silicoformate, 141
Silicon Trichloride, 181
Triethylate, 181
Sorbic Acid, 305
Stannonic Acid, 183
Succinaldoxime, 355
Succinic Acid, 493
Succinimide, 498
Sulphide Acetic Acid, 376
Sulphides, 142, 143
Sulphocarbamide, 452
Sulphochloride, 147
Sulphonate, 147
Sulphone Acetic Acid," 377
Propionic Acid, 377
Sul phones, 146
Sulphonic Acid, 147, 245
Ethyl Acetic Ester, 377
Sulphoxides, 145
Sulphurane, 325
Sulphuric Acid, 8x, 104, xii.ne, 126. 139,
Chloride, 140
Tartronic Acid, 550
Telluride, 148
Tetronic Acid, 4^0, 544
Thiocarbamic Ethyl Ester, 449
Thiocarbonic Acid, 43*
INDEX
697
Ethyl Thionamic Acid, 168
Thiosulphuric Ethyl Ester, 147
Tr carballylic Acid, 504
Uramil, 578
Urea, 440
Chloride, 438
Valerolactam, 396
Xanthic Acid, 433
Formic Ester, 433
Ethylamine, in, 164
Ethylene, 80
Bromide, 81, 86, 322, 613
Chlorhydrin, in, 319
Chloride, 81, 312, 323
Cyanhydrin, 380
Cyanide, 499
Diamine, 322, 333, 436
Derivatives, 322, 333
Dicarboxylic Acid, 492
Diethyl Sulphide, 324
Sulphone, 325
Dimalonic Ester, 613
Dimethyl Sulphide, 324
Dinitramine, 333
Disulphinic Acid, 327
— Disulphonic Acid, 327
Dithioethylidene, 324
Ester, Carbonic, 428
Dithiocarbonic, 433
Ethenyl Amidine, 333
Ethylidene Ether, 317
Glycol, Thio- compounds of, 324 ; Mercap-
tans, Sulphides, 324 ; Sulphine derivatives,
Sulphones, Sulphonic Acid .325
Glycols, 82, 99, 192, 224, 312, 313
Halides, 322
Hydrinsulphonic Acid, 325
Imide, 166
Imine, 335
Iodide, 322
Lactic Acid, 317, 889, 371
Mercaptal, Arabinose, 618
, Dextrose, 634
• Mercaptals, 324
Mercaptan, 324
Mercaptols, 324
Methylene Ether, 316
Nitrate, 323
Oxalic Ester, 482
Oxide, 107, 118, 192, 216, 817, 318, 539, 550
Carboxylic Acid, 193, 287, 605
Pseudothiourea, 453
Bis-phthalimido-malonic Ester, 606
Selenocyanide, 468
Succinic Acids, 491, 613
— • Chlorides, 495
Nitrogen Derivatives, 496, 497 498,
499
Sulphide, Polymeric, 324
Sulphocarbamide, 452
Sulphone Anilide, 147
Sulphonic Acid, 147
Tetracarboxylic Ester, 613
Tetramethyl Halides, 322
Thiocyanate, 468
Thiohydrate, 324
Trimethyl, 83
Ureas, 441
Derivatives, 441 .446
Urethane, 436
Ethylidene, Acetoacetic Ester, 425
Acetone, 229
Azine, 214
Bromide, 206
Chlorhydrin Acetate, 207
Chloride, 80, 208, 492
Cyanacetic Ester, 508
Diacetate, 200, 207
. Diacetic Acid, 502
Diethyl Ether, 205
Sulphone, 210
Dimalonic Ester, 508, CIS
Dimethyl Ether, 205
— — Disulphonic Acid, 209. 21ft
Ethylidene, Dithioglycollic Acid, 376
Diurethane, 436
Glycols, Carboxylic Esters of, 207
, Ethers and Esters of, 204
Glutaric Acid, 522
Iodide, 206
Lactic Acid, 362, 369
Halogen Derivatives, 368
Nitrite, 379
Malonic Ester, 292, 508, 613
Methyl Butyrolactone, 423
Glutaric Acid, 296, 622
Pyrotartaric Acid, 520
Oxide, 199
Phenylhydrazine, 213
Propionic Acid, 292, 298
Succinic Acid, 490, 518
Urea, 441
Ethylidenimine, 212
Ethylidine Chlorhydrin Acetate, 207
Ethylimidopyruvyl Chloride, 248
Euglena viridus, 662
Euonymus europ&us, 530
Euxanthone 653
FAECES, 333
Fat, Wool, 265
Fats, 261, 262, 284, 492, 506, 527, 530
Technical application of the, 264
Fatty-acid Derivatives, 284
Esters, 265
Nitramines, 396
Nitriles, 252, 278
Fatty Acids, 251, 260
, Halogen Substitution Products ot
the, 284, 290
, Isonitramine, 396
Synthesis and Decomposition of, 262
Fehl ing's Solution, 603, 628
Fellic Acid, 676
Ferment, Fibrin, 670
Maltase, 633
My rosin, 470
Fermentation, Butyric, 261, 363, 365
Butyric Acid of, 259, 631
Citric Acid, 631
Lactic Acid, 363, 365, 631
Mucous, 631
Ropy, 623
of Calcium Malate, 492
of Glycerol, 315
of Lactic Acid, Butyric, 259
of Starch, Butyric, 259
of Sugar, Butyric, 259
of the Hexoses, 631
Ferments, 1 13, 264, 38 1, 62 6, 658, 659, 660,663, 877
Butyric, 365
Decomposition of Fats by, 264
Ferrocyanide, Potassium, 243
Ferrofulmirate, Sodium, 250
Fibrin, Globulin, 670
— Putrescence of, 394
Fibrinogen, 670
Fibroin, 392, 540
of Silk, 386, 388
Fire-damp, 71
Fish, Decay of, 334
Fish-sperm, 674
Flaveanic Acid, 486
Flesh, Putrescence of, 394
Fluoracetic Acids, 288
Fluorescence, 51
Fluorethylene, 97
Fluorochlorobromoform, 247
Fluorochloroform, 247
Fluoroform, 246
Fly agaric, 329, 34<>
Formal, 205
Formalazipe, 214
Formaldehyde, in, 158, 163, 197, 203, 337- 527,
631, 663
Derivatives, 209, 029
I Peroxide, 203
698
INDEX
Formaldehyde Sulphoxylate, 308
Formaldoxime, 213
Formalhydrazine, 214
Formalin, 198
Formamide, 288, 239, 277
Derivatives, 239, 240, 409
Formamidine, 243, 244, 282, 455
Formamidoxime, 243, 244, 283
Formamine Acetic Acid, 388
Formazyl Carboxylic Acid, 244, 488
• Hydride, 244
Sulphonic Acid, 454
Formhydroxamic Acid, 243, 244, 283
Formic Acid, no, 193, 215, 236, 400, 631
Derivatives, 407, 408
Esters, no, 192, 194, 238, 243, 530
• — , Ortho-, Esters of, 141
, Nitrile of, 239
Formimido-ether, 192, 243,, 281
Derivative, 244
Formisobutyric Aldol, 339
Formocarbothialdine, Dimethyl, 450
Formoguanamine, 457, 474
Formonitroxime, 244
Formose, 636
Formoxime, 313
Formulae, Constitutional, 31
Empirical, 21, 25
Rational, 25
Structural, 31, 22, 90, 91
Formyl Acetic Acid, 398, 401
Guaneide of, 574
Acetoacetic Ester, 545, 546
Acetone, 843, 348
Chloridoxime, 243, 244, 249
Diacetyl Methane, 536
Glycocoll, 385, 388, 401
Hippuric Arid, 540, 543
• Hydrazine, 239
Ketones, 343
• Leucine, 390
Malonic Acid, 560, 561
Methyl Thiosemicarbazide, 454
Tricarboxylic Ester, 592
— — Trisulphonic Acid, 235, 247, 429
Urea, 441
Valine, 389
Fraxinus chivensis, 269
Freezing-point, Determination of the molecular
weight from the depression of the, 15 ; Beck-
mann's method ; Eykemann's method, 17
Fructosamine, 637
Fructose, 198, 215, 617, 623, 626, 631, 632, 633,
635, 636, 637, 651, 659, 661
Fruit essences, Artificial, 267
Fulgenic Acid, 522
Fulgide, 522
Fulminate, Metallic, 250
Fulminic Acid, 236, 247, 248
Fulminuric Acid, 250, 535, 549
Fumaramic Acid, 509
Fumaranilic Acid, 510
Fumarazide, 510
Fumardianilide, 510
Fumarethyl Ure thane, 510
Fumarhydra/ide, 510
Fumaria officinalis, 509
Fumaric Acid, 63, 65, 87, 509, 511, 567, 592,600,614
• Derivatives, 514
Acids, Alkyl, 420, 519
— — , Isomerism of, 512
Dialdehyde, 347
Fumaryl Glycidic Acid, 605
Peroxide, 509
Fungi, 114, 509, 631, 661
Fission, 631
Furazan Carboxylic Acids, 545, 568, 608
Furazanes, 355
Furfural, 106, 348, 618
Furfurane, 818, 347, 35 1, 654
Carboxylic Acids, 654
Furodiazoles, 355, 536
Furonic Acid, 506
Fusel Oil, 114, 117, 119, 361, 363
GALACTAMINE, 624
Galactans, 635
Galactitol, 635
Galactochloral, 635
Galactodextrose, 660, 661
Galactonic Acid, 374, 618, 619, 650
Lactone Chlorhydrin Triacetyl, 650
Nitrile, Pentacetyl, 619, 850
Galactose, 113, 114, 618, 619, 624, 630, 635, 636,
660, 661
Carboxylic Acids, 635, 651, 655
Galactosidodextrose, 658, 661
Galactosimine, 636, 651
Galaheptanepentol, Diacid, 655
Galaheptonic Acids, 637, 651, 655
Galaheptosaminic Acid, 651
Galaheptose, 637, 651
Galaoctonic Acid, 637, 652, 654
Galaoctonolactone, 652
Galaoctose, 637, 650, 651, 654, 660
Galapeptose, 652
Gallic Acid, 408
Gallisin, 632
Gallium, Alkyl Derivatives of, 188
Galtpse, 630
Garlic, 144
Oil of, 123
Gas, Illuminating, 71, 87, 90, 93
" Olefiant," 322
Gastric Juice, 363, 672
Gaultheria procutnbens, no
Gelatin, 392, 540, 542, 598, 673
Blasting, 665
Putrescence of, 394
Tannate, 673
Geranial, 215
Geraniol, 232, 422
Germanium, Alkyl Derivatives of, 181
Glaucophanic Acid, 546
Gliadin, 392
Globulins, 670
Gloxypropionic Acid, 423, 545
Glucamines, 624
Glucase, 660
Gluco- compounds. See Dextro- compounds
Glucohepitol, 625
Glucoheptonic Acid, 651, 6Co, 661
Lactone, Dimethylene, 651
Glucoheptose, 651
Gluconic Acid, 374, 618, 634, 641, 649, 653, 660
Lactone, 633
Tetramethyl, 634
Glucononitol, 625
Glucononitrile, Pentacetyl, 617, 634, 649
Glucononose, 625, 637
Gluco-octitol, 625
Gluco-octonolactone, 652
Gluco-octose, 625, 637
Glucopentahydroxypimelic Acid, 653
Glucoprqtei'ns, 671
Glucosamine, 633, 636
Glucosaminic Acid, 651
Glucoses, Alkyl, 883, 634. Set also Dextrose
Glucosides, 470, 626, 633
Glue, 385
Glutaconamide, 520
Glutaconaminic Acid, 520
Glutaconic Acid, Dicarboxyl, 613
Anhydride, 520
Dialdehyde, 347
Acids, 502, 515, 620, 521, 559, 561
Derivatives, 571, 561, 607
Glutamine, 559
Glutaminic Acid, 658, 667, 670
Glutaric Acid and Esters, 296, 424, 501, 543, 593,
615, 620, 622
Half Aldehyde of ,403
Nitrile of, 502
Derivatives 503, 503, 504, 522, 56o,
570, 593, 605, 606
Dialdehyde, 347, 408
Diazide, 333, 503
Dioxide, 502
Dihydrazide, 502
INDEX
699
Glutaric Peroxide, 50*
Glutarimide, 502
Giutazine, 569
Gluten Proteins, 670
Glutin-peptone, 668
Giutinic Acid, 523
Glutolactonic Acid, Methyl, 433
— — Derivatives, 559
Nitrile, 422
Glyceraldehyde, 583, 630
Derivatives, 534
Glyceric Acids, 258, 289, 364, 368, 389, 525, 538.
539
Glycerides, 530, 531
Glycerol Acetal, 532, 534
, Acrolem, 532
Benzal, 532
Diethylin Derivatives, 532
Esters of Inorganic Acids, 529, 530
of Organic Acids : Formic Acid,
237 ; Myristic Acid, 531
Ethers, 206, 214, 531, 532
Fermentation of, 314
Formal, 532
Mercaptans, 530
Triurethane, 533
Glycerols, 99, 114, 123, 214, 237, 313, 3M> 34*,
628, 531, 562, 663
Nitrogen Derivatives of the, 533, 597
Glycerophosphoric Acid, 329, 531
Glycerose, 525, 528, 534, 616, 636
Glyceryl Chloride, 529
Glycide Compounds, 532, 533
Glycidic Acids, 368, 639, 540
Acid, Fumaryl, 605
Glycine. See Glycocoll -
Glycocholic Acid, 386, 388, 676
Glycocoll, 241, 362, 381, 385, 390, 405, 443, 581,
666, 673, 674
Amidoxolyl, 484
• Derivatives, 392, 393, 403, 437
Hydrazide, 386
Nitrile, 386
Substituted, 330, 387
Glycocollamide, 386
Glycocollic Ester, 386
Derivatives, 366, 379, 386, 462
Glycocyamidine, 456
Glycocyamine, 456
Methyl, 387, 456
Glycogen, 660, 662
Glycol Acetals, 312, 316, 320, 323, 387, 338
Derivatives, 324
Aldehyde. See Glycollic Aldehyde
Azide, 378
Bromhydrin, 319
Carbonate, 428
Chloracetin, 323
Chlorhydrin, 117, 312, 319
Chloride Hydrochloride, 386
Diacetate of the Olefine, 342
Diformin, 323
Dinitrate, 313, 323
Dipalmitate, 324
Distearate, 324
Ethers, 316
Ethylene, 99
— Hydrazide, 378
lodacetin, 324
lodohydrin, 319, 320
Methylene, 199
Nitro-bromo-trimethyle&e, 534
Tribromethylidene, 203
Trichloretbylidene, 202
Nitrohydrin, 328
Sulphuric Acid, 323
Glycols, 216, 306, 312, 373
Acetylene, 315
. Esters of, 319
— Homologous, 313-3*5
Hydroxyalkyl Bases, 328
Nitrogen Derivatives of, 327, 328
Olefine, 315
Paraffin, 307. 313
Glycoliminohydrin, 378
Glycollamide, 378
Glycollic Acid, 116, 256, 287, 312, 862, 366, 401,
477, 528,545,636
• Esters, 367
Nitrile, 379
Aldehyde, 117, 198, 203, 337, 606, 616
Anhydride, 367
Ester, Chlorocarbonate, 430
Glycollyl Aldehyde. See Glycollic Aldehyde
Glycolureine, 441
Glycoluric, 347, 441, 442, 573
Acid, 442
Glycolyl Guanidine, 456
Malonic Acid, 607
Pyroracemic Acid Phenylhydrazone, 343
Urea, 442
Glycosine, 346
Glycuronic Acid, 538
Glycyl Alanines, 392
Aspartic Anhydride, 553
Aspartyl Leucine, 556
Glycine, 391, 392
Derivative, 437
Valyl Anhydride, 674
Glyoxal Acetals, 346
Bisguanidine, 355
Disemicarbazone, 355
Osazone, 356
Osotetrazone, 356
Sodium Sulphite, 346
Glyoxalic Acid. See Glyoxylic Acid
Glyoxaline Derivatives, 484
Glyoxalines, 333, 348, 347, 349. 354. 451
Glyoxals, 116, 203, 312, 846, 441, 477, 608, 633
Glyoxime Peroxides, 355
Propionic Acid, 546
Ring, 573
Glyoxyl Carboxylic Acid, 545, 546
Thiocarbimide, 573
Urea, 573
, Acetyl, 574
Glyoxylic Acid, 116, 203, 235, 287, 312, 388 .400,
405,444, 562
Acetyl, 546
Diurethane, 436
Guanidine, 573
Phenylhydrazone, 405
Amide, Azine of, 405
Glyoxyl Propionic Acid, 423, 84*
Gooseberries, 400, 551
Granulo-bacillui, 365
Granulose, 661
Grapes, 551, 601
Gravity, Specific, 43
Groups, 24
Guaiacol, 607
Resin, 215
Guaiol, 215
Guanamines, 455, 474
Guanazine, 459
Guanazole, 458
Guaneides of the Acids, 455, 457, 574
Guanidine, Acetic Acid, 456
Glyoxylic Acid, 573
Malonyl, 576
Oxalyl, 576
Propionic Acids, 457
Guanidines, 250, 426, 454, 455, 673
Derivatives, 568
Guanidinobutyric Acid, 542
Guanidocarbonic Ester. 457
Guanidodicarbonic Diethyl Ester, 457
Guanine, 455, 572. 587, 688, 672
Guano, 455, 581, 588
Gnanoline, 457.
Giianyl Guanidine, 457
Thiourea, 458
Urea, 457
! Guarana, 590
Gulonic Acid, 619, 635, 649, 650
Gulose, 634, 639. 650
Gum, Cherry, 618, 663
I Arabic, 650, 663
700
INDEX
Gum Tragacanth, 663
Gums, 631,
Guncotton,
Gums, 631, 635, 662
\, 664
HEMATIC Acid, 519, 595, «70, 676
Haeraatin, 519
Chloride, 675
Haematinlc Acid. See Haematic Acid
Haematochromogen. 675
Haematoporphyrin, 675, 676
Hasmin, 675
Haemoglobins, 674
Haemolysis, 676
Haemopyrrole, 675, 676
Haemotricarboxylic Acid, 594
Hair, 541
Halochroism, 41
Halogen Acetylenes, 98
Alkyls, 93, 131
Esters of the Alcohols, 131
— — Mononitro-paraffin, 148
Nitro-compounds, 151
Nitrosoparaffin, 152, 153
defines, 96, 136, 225,
Halogens, Determination of the, 8
Heat, Action of, 61
Hemiterpene, 91
Henbane, 333
Hentriacontane, 77
Hepta-acetyl Chlorolactose, 660
Heptachlorethylidene Acetone, 229
Heptachloropropane 225
Heptacosane, 77
Heptadecyl Methyl Ketone, 263
Heptadecylic Acid, 262
Heptahydric Alcohols, 624
Heptahydroxy- Aldehydes and Ketones, 625
Heptamethylene Chloride, 323
Diamine, 334
Glycol, 315
Imines, 335
Heptane, 76, 77, 122
Acids, 598, 599
Hcptenyl Amidoxime, 283
Heptitols, 637
Heptolactam, 396
Heptolacton* Acetic Acid, 560
Heptolactones, 299, 876, 651
Heptoic Acid, 261
Ester, 268
Heptyl Alcohol, 122
Mustard Oil, 470
Propiolic Acid, 304
Heptylic Acid, 396, 650, 651
Heracleum gigantentn in
sphondylium, in, 122, 256, 268
Herring-brine, 165
Heteroxanthine, 689, 590
Hexachloro-p-diketo-R-hexene, 514
Hexachlorodimethyl Tetroxan .205
Trioxan, 205
Hexachloro-R-pentenes, 305
Hexachloropropylene, 295
Hexacontane, 76, 122
Hexadecane, 76
Hexadecyl Methy Ketone, 263
Hexadecylene, 268
Hexadecylic Acid, 262
Hexa-di-me-diol, 316
Hexaethyl Melamine 475
Hexaethylidene Tetramine, 212
Hexahydric Alcohols, 622
Hexahydropyrazine, 336
Hexahydroxy- Aldehydes and -Ketone 625
Hexaketones, 647
Hexamethyl Ethane, 75, 77
Hexamethyl Melamine, 474
Hexamethylene Chloride, 323
Diamine, 334
Diethyl Urethane, 334
Glycol, 315
- • • Imines, 335
— — Ketone Isoxime, 395
Hexamethylene Tetracarboxylic Esters, 613, 614
, Tetramine, 198, 210, 211
Triperoxydiamine, 2*4
Hexane, 75, 78, 77
Dekacarboxylic Ester, 656
Hexacarboxylic Ester, 656
Hexane-diol. 310
Hexane-trio!, 528
Hexaoxymethylene Diamine 204
Hexenyl Amidoxime, 283
Hexenpne, Trimetbyl cyclo-, 221
Hexenic Acids, 299, 395
Hexetbyl, Disilicon, 181
Hexinic Aeid, 544
Hexitols, 622, 639
Space Isomerism, 641
Hexonic Acids, 641
Hexoic Acid, 261
Esters, 268
Hexose Amines, 624, 636
Carboxylic Acids, 651
Imines, 636
Methyl, 635
Hexoses, 626, 639, 672
• Synthetic and Degradation Reactions of
the, 630
Ilexoxybenzene, Potassium, 247
Hexyl Alcohol, 122
Mustard Oil, »-, 470
Hexylene Dioxide, 597
Glycol, 315
Oxide, 318
Hippophne rhamnoides, 551
Hippuric Acid, 385, 386, 388, 581, 666
Ester, Derivatives, 540, 543
Formyl, 540
Hippuryl Aspartic Acid and Compounds, 542, 558
Azide, 392
Histidine Propionic Acid, 547
Hoffmann's Anodyne Spiritus Actbereus, 128
Hofmann Rearrangement, 160
Homoaspartic Acid, 556
Homocholine, 329
Homoconiinic Acid, and Derivatives, 394, 396
Homolaevulinic Acid, 423
Homoraesaconic Acid, 521
Homopyroracemic Acids, 408
Homopyruvyl Pyruyic Acid, 599
Homoterpenylic Acid, 558
Horn, 390, 540, 541
Hydantoic Acid, 442, 455
Hydantolns, 442, 443, 456, 457, 573
Hydracetamide, 212
Hydracetyl Acetone, 221, 229, 342
Ketones, 342
Hydracrylic Acid, 314, 317, 369
Substituted, 370
Aldehyde, 338
Hydramines, 328
Hydraziacetic Acid, 405
Hydrazicarboxylic Ester, 447
Hydrazides, Acid, 278
of the Hydroxy-acids, 378
Hydrazidine, 234, 284
Hydrazine, 169, 212, 378, 405, 458
Carboxylic Acids, 439, 446
Derivatives, 239, 378, 446, 454
Hydrazino-fatty Acids 397, 405
Hydrazino-nitriles, 213
Hydrazino-olefine Carboxylic Ac ds, 399
Hydraxipropionic Ethyl Ester, 410
Hydrazodicarbonamide, 448 459
Hydrazodicarbonamidine, 458
Hydrazodicarbonic Ester, 447
Hydrazodicarbonimide, 447, 448
Hydrazo-fatty Acids, 397
Hydraioformamide, 447
Hydrazoic Acid, 171, 405, 447, 458, 459
Hydrazones, Aldehyde, 213
Hydrazonomesoxalic Diamide, 564
Hydrazo oxime, 284
Hydrazotetrazole, 459
Hydrocarbons, 69
Saturated, 69
INDEX
701
Hydrocarbons, Unsaturated, 79
Hydrocellulose, 664
Hydrocholidonic Acid, 570
Hydrocyanic Acid, 164, 236, 239, 460
Hydrocyanuric Acid, 474
Hydroferrocyanic Acid, 243
Hydrogen, Determination of, 3
Hydrolysis, 118, 131, 251, 277
Hydromuconic Acid, 505, 622
Hydronitroprussic Acid, 243
Hydrorubianic Acid, 486
Hydrosorbic Acid, 299, 305, 370, 540, 557
Hydrosulphides, Alkyl, 142
Hydrouracil, 444, 573
Hydroxalkyl Phosphinic Acids, 196
Hydroxamic Acids and Derivatives, 150, 152, 160,
194, 234, 282, 499
Oxime, 234, 288
Tetracetate, Succinyl, 499
Hydroxamides, 378
Hydroximic Acid Chlorides, 283
Hydroximidocyanovaleric Acid, 542
Hydroxyacetic Acid, 357, 802
Derivatives, 298, 543
Hydroxyacetoacetic Acids, 543
Carboxylic Ester, 607
Lactones, 544
Hydroxyacetone, 338, 341
Hydroxy-acid Nitriles, 207, 221, 378
Hydroxy-acids, 850, 362, 366, 371, 356, 365
Alkyl Derivatives, 366, 367
Anhydride formation of the a-, 366
Cyclic Double Esters of the, 367, 385
Esters, 368
Guaneides of the, 455
Halogen, 368
Nitrogen Derivatives, 378
Sulphur Derivatives, 376
Ureides of, 442
Hydroxyacrylic Acid, 898
Derivatives, 401
Hydroxyadipic Acid, 560
Hyclroxyalkylamines, Haloid Esters of the,
Hydroxyamido-oximes, 284
Hydroxyaminoglutaminic Ester, 569
Hydroxyaminopropionacetal, 534
Hydroxyaminopropionic Acid, 393, 541
Hydroxyaminosuccinic Acid, 605
Hydroxyazelaic Acid, 571
Hydroxybehenic Acid, 376
Hydroxybutyl Aldehyde, 338
Hydroxybutyraldehyde, 196, 338
Hydroxybutyric Acid, 296, 297, 34i> 365, 370,
37i, 375
Nitrite, 379
Hydroxybutyrolactone, 297
Hydroxycaffeine, 583, 691
Hydroxycaproic Acids, 299, 365, 870, 876
Hydroxycaprolactone, 299, 640
Hydroxycaprylamide, 378
Hydroxycaprylic Acid, 86
Nitrile, 379
Hydroxycarboxylic Acids, 36*
Saturated, 362
Unsaturated, 367, 368, 401
Monohydroxy-, 193, 356, 548, 610
Di-f 538, 599
Tri-, 598, 621
Tetra-, 619, 652
Penta-, 652, 655
Poly-, 652
Hydroxycitric Acid, 620, 622
Hydroxycro tonic Acid, 398
Hydroxy-dimethyl-aminoacetic DimetUyl Amide,
402
Hydroxyethylamine, 329
Sulphur derivatives of, 331
Hydroxyethyl-phthalimido-malonic Mono-ester
Lactone, 541
HydroxyethylTr.methyi Ammonium Hydroxide,
329
Hydroxyethylene Oxides, 340
Hydroxyfatty Acid Esters, *87, 399
Hydroxyfumaranilic Acid, 565
Hydroxyfumaric Acid and Ester, 565, 566
Hydroxyfurazan Carboxylic Acid and Deriva-
tives, 564 , 567
Hydroxyglutaric Acid 297, 504, 658, 559, 560
Lactone, 570
Hydroxyguanidine, 458
Hydroxyhexenic Acid, 305 897
Hydroxyhydrosorbic Acid, 398
hydroxyhydrosulphides, 208
Hydroxyimidobydrines, 378
Hydroxyiso butyl Imidohydrine, 378
Hydroxyisobutyric Acids and Derivatives, 297,
365, 870, 379, 443
liydroxyisocaproic Acids, 365, 370
Hydroxyisocaprolactone, 540
Hydroxyisoctylic Acid, 371
Hydroxyisoheptolactone, 540
Hydroxyisoheptylic Acid, 370
Hydroxyiso-octolactone, 540
Hydroxy-di-isopropyl Acetic Acid, 366
Hydroxy-di-n-propyl Acetic Acid, 366
Hydroxyisoxazole Carboxylic Ester and Deriva-
tive, 569
Hydroxyisosuccinic Acids, 550
Hydroxyisovaleric Acids and Derivatives, 260,
298, 366, 370, 379
Hydroxyketone Carboxylic Acids, 543, 598, 607,
652, 655
Hydroxyke tones, 340, 534, 536, 597, 620
Hydroxyl Ethyl Sulphide, 324
Oxamide, 484
Urea, 448
Hydroxyketopentane, 342
Hydroxylactones, 640
Hydroxylaevulinic Acids, 423, 425, 645
Hydroxylamines, Alkyl, 152 163, 171
Nitroso-alkyl, 172
Hydroxylaminoacetic Acid, 381
Hydroxylamino-fatty Acid, 381
Hydroxylaminoisobutyric Acid, 381
i Hydroxylamino-ketones, 345
1 Hydroxylamino-oximes, 229
hydroxylauric Acid, 366
Ilydroxymalelc Acid and Derivatives, 565
Ester, 566
Hydroxymalonic Acid Group, 549
Hydroxy-mercury Propionic Anhydride, 289
Hydroxymethane Disulphonic Acid, 210, 247
Hydroxymethylene Disulphonic Acid. See
Hydroxymethane Disulphonic Acid
Ketones, 848, 348, 636
Hydroxymyristic Acid, 366
Hydroxycenanthylic Acid, 375
Hydroxypalmitic Acid, 366
Hydroxyparaconic Acid, 515, 605
Ilydroxypentenic Acid, 397, 420
Hydroxypivalic Acid, 298, 870
Acid, Vinyl, 398
Hydroxyproline, 698, 667
Hydroxypropiolic Lactone, 488
Hydroxypropionacetal, 838, 347
Hydroxypropionaldehyde, 338
Hydroxypropionic Acid, 314, 86Z
Lactone, 488
Hydroxypyroracemic Acid, 543
Aldehyde, 536
Hydroxypyrotartaric Acid, 556
Hydroxypyrrolidone Carboxylic Acid, 598
Hydroxysebacic Acid, 560
Hydroxystearic Acid, 366, 375
Hydroxysuccinic Acid, Methyl, 260
Hydroxysulphine Carboxylic Acids, 377
Hydroxysulphonic Acid, 2 ro
Hydroxytetrahydrofurfurane Carboxylic Acid,
598
Hydroxytetrinic Acid, 420, 516
Hydroxythioureas, Alkyl, 454
Hydroxytricarballylic Acid, 610, 622
Derivative. 612
Hydroxyundecylic Acid, 376, 507
Hydroxyurethane, 448
Hydroxyvaleric Acids, 298, 365, 870, 540
Derivatives, 370, 522. 599
702
Hydroxyvalerolactone, 540
Hydurilic Acid, 580
Hyocyamus, 333
Hypochlorous Acid, Esters of, 141, 446
Hypogaeic Acid, 300
Hypoxanthine, 572, 586, 587, 689, 672
ICELAND Moss, 509, 662
Iditols, 624, 635, 636
Derivatives, 624
Idonic Acid, 619, 635, 660, 653
Idosaccharic Acids, 642, 653
Idose, 624, 636, 650
Ilex paraguayensis, 590
Imidazoles, 344
Imidazolyl Mercaptans, 344
Imide Compounds, 156, 165, 168, 479, 487
Chlorides, 234, 281
Imidoallantom, 573
Imidoalloxan, Barbituryl, 581
Imidazolone, Amino-methyl, 588
Imidocarbonic Acid, Derivatives of, 445
Imidodicarboxylic Hydrazide, 447
Imidodioximidocarbonic Acid, 445
Imidodithiocarbonic Esters, Hydroiodides of, 450
Imidodithiocarboxylic Acid, 448
Imidoethers, 191, 234, 281
Imidoformyl Cyanide, Chlorethyl, 485
Imidohydrines, 378
Imidomalonamide, 563
Imidooxalic Ethers, 486
Imidooxalomalonic Ester, 612
Imidothiodisulphazolidine ,467
Imidothiourasole, 454
Iminoacetoacetic Ester, 419
Nitrile, 419, 420
Iminoacetonitrile, 388
Iminobarbituric Acid, 576
Iminodiacetic Acid, 388
Iminodilactic Acid, 409
Iminodipropionic Acid, 389
Iminodipropionimide, 389
Iminoisobarbituric Acid, 576
Iminomalonamide, 550
Iminosuccinamic Ester, Acctyl, 609
Imjnosuccinic Ester, 605
Iminosuccinimide, Acetyl, 609
Irainotbiobarbituric Acid, 5/6
Indium, Alkyl Derivatives of, 188
Indole and Derivatives, 406, 667. See also Pyra-
zine Derivatives .423
Insect Wax, 269
Insects, Excrements of, 581
Intramolecular Atomic Rearrangements, 36, 369,
68 1
Inulin, 635
Invert Sugar, 118, 620, 635, 658, 659
Invertin, 118, 658, «77
Iodides, 134, 178, 182
Iodine, 5
Starch Reaction, 66a
lodoacetal, 205
lodoacetic Acids, 288
lodoacetone, 224
lodoacetoxime, 345
lodoacetylene, 98, 303
lodoacrylic Acid, 295
lodobutyric Acid, 289, 290, 296, 297
lodoethane, 136
lodoethyl Ether, 129
— — Trimethyl Ammonium Iodide, 333
lodoethylamine, 331
lodoform, 94, 222, 235, 246, 428
Reaction, no, 115, 222
lodoglutaric Ester, 502
lodohydrin, 529
lodoiso propane, 136
lodolactic Acid, 368
lodoleic Acid, 302
lodomethane, 136
— — Disulphonate Potassium, 134
lodopropiolic Acid, 303
lodopropionaldehyde, 529
INDEX
lodopropionic Acid, 288, 289, 369, 503
lodosochloracrylic Acid, 285, 515
lodosochlorochloracrylic Acid, 295
lodosochlorochlorofumaric Acid, 295
lodotetronic Acid, 544
Ir is root, 262
Iron Carbonyl, 247
Isaconic Acids, 520
Isethionic Acid, 324, 826, 327, 331
Isoactoneitrile, 248
Isoacetoxime Sodium Iodide, Methyl, 227
Isoaconitic Ethyl Ester, 595
Isoallylamine 166
Isoamyl, Chlorophosplmies, 175
- Dithionic Acid, 274
- Ethyl Alcohol, Isopropyl, 107
- Nitrate, 137
- Nitrous Ester, 138
- Zinc, 187
Isoamylamine, 165
Isoamylene, 83, 86, 121, 343
- Glycol, 313, 314
Isoamylidine Acetone, 229
Isoasparagme, 555
Isobromomethacrylic Acids, 297
Isobutane Tricarboxylic Ester, 593
Isobutyl, Acetaldehyde, 201
- Acetamide, 278
- Acetonitrile, 280
- Acrolem, 215
- Alcohol, 119
- Aldehyde, 201, 310, 320
- Butyrolactone, 375
- Carbamine-thiolic Acid, 448
- Carbinol, 114, 119, 120
-- Derivatives 268
- Glycerol Dietbylin, 532
- Hydanto'ic Acid, 443
- Hydantoin, 443
- Mustard, oil, 470
- Nitrate, 137
- Succinimide, 498
-- Zinc, 187
Isobutylamine, 164
Isobutylene, 75, 80, 82, 84, 119
- Glycol Chlorhydrin, 320
- Oxide, 318
: - Tricarboxylic Ester, 502
Isobutyiidene Acetone, 229
Isobutylonitrile, 280
Isobutyraldpxime, 213
Isobutyramide, 277
Isobutyric Acid, 119, 258, 259
Derivatives, 268, 402
Aldol, 339
Formaldehyde, 348, 421
339
423
- Isovaleric Aldol,
Isobutyrom, 342
Isobutyrone Oxime, 227
Isobutyryl, 343
- Chloride, 271, 315
- Cyanide, 409
- Formaldehyde. See Isobutyric Formalde-
hyde
- Isobutyric Ester, 414, 418
Isocaprolactone, 299, 374, 559
Isocholesterol, 677
Isocholine, 329
Isocitric Acid, 557, 611
Isocro tonic Acid, 292 ,295, 297
- Anilide, 298
Isocyanate, Carboxethyl, 445, 463
Isocyanates, 159, 242, 481, 463,475
Ispcyanides. See Isonitriles
Isocyanogen, 459
Isocyanotetrabromide, 459
Isocyanoxide, 459
Isocyanuric Acid, Esters of, 159
-- Imides of, 473
Isocystelne, 542
- Acid, 542
Isocystinc. 542
Isodehydracetic Acid, 399, 417. 521, 671
Isodextrosamine, 624, 633, 637
INDEX
703
Isodlaluric Acid, 577
Isodiazoacetic Ester, 403
Isodibromosuccinic Acid, 800, 508, 605
Isodibutylene, 83
Isodibutyryl, 315
Isodichlorobutyric Acid, 297
Isodicblorosuccinic Acid, 500
Isodiisobutyryl, 315
Isodiisovaleryl, 315
Isodipropionyl, 315
Isodulcitol, 619
Isoerucic Acid, 301
Isohexenic Acid, 299
Isohexeric Acid, 539
Isohexylene Glycols, 814, 315
Isohydracetic Acid, 417
Isobydrosorbic Acid, 299
Isohydroxy butyric Acid, 297
Isohydroxyurea, 448
Isolaurpnolic Acid, 424
Isoleucine, 890, 667
Isomalic Acid, 550
Isomelamines, 473 ,474
Isomerism,25
• Aloergatic, 209, 514
Dynamical, 494
Geometrical, 32
Isomuscarine, 340
Isonitramine Acetic Acid, 397, 381
Acetoacetic Acid, 544
Ester, 416
• Fatty Acids, 896, 403
Isonitroso Derivatives, 416
Isonitriles, 158, 192, 236, 246, 247 279
Isonitroethane, Benzoyl, 151
Isonitroform, 155
Isonitro-paraffins, 150
Isonitropropane, 151
Isonitrosoacetoacetic Ester, 543, 646, 608
Isonitrosoacetone, 354
Dicarboxylic Ester, 569
Isonitrosoacetic Acid and Ester, 250, 405 608
Isonitrosoacetyl Acetone, 536
Isonitrosobarbituric Acid, 580
Isonitrosocyanacetamide, 564
Isonitrosocyanacetic Acid and Ester, 563, 564
Isonitrosocyanacetohydroxamic Acid, 564
Isonitroso-fatty Acids, 153, 381, 405, 453
Isonitroso-ketones, 219, 344, 349, 353, 354
Isonitrosolaevulinic Acid, 647, 568
Isonitrosomalonic Acid, 550, 563
Isonitroso-malonyl-urea, 563
Isonitroso-methyl-isoxazolone, 547
Isonitrosonitroacetic Ester, 405
Isonitroso-nitro-succinic Acid Nitrile, 380
Isonitrosopropionic Acid, 410
Iso-octenolactone, 398
Iso-oleic Acid, 301
Isoparaconic Acid, Isopropyl, 517
Isophorone, 221, 229
Isopral, 364
Isoprene, 91
Isopropenyl Ethyl Ether, 29, 418
Isopropyl Acetonitrile, 280
Alcohols, 114, 117, 527, 529
Barbituric Acid, 577
Bromide, 135
Butyrolactones, 375
Carbinol, 119
Ether, 129
Ethylene, 85
Oxide, 318
Glyoxal, 348
Iodide, 118, 1*6, 313
Isoamyl Ethyl Alcohol, 107
Methyl Bu tyro) ac tone, 375
Caprolactone, 375
Mustard Oil, 470
Nitrate, 137
Pyrolidone, 395
Succinimlde, 498
Isopropylamine, 164
Methyl Carbinol Acetate, »6j
—• - Ketone, 3x4
Isopropylamine, Zinc, 187
Isopropyl-heptane-2-one Acid, 5, 424
Isopropylidene Acetoacetic Ester, 425
Cyanacetic Ester, 508
Isobutylidene Succinic Acid, 522
Isopurone, 582
Isopyrotritaric Acid, 351
Isoquinoline, 62, 69
Isorhamnonic Acid Lactone, 619
Isorhamnose, 619
Isosaccbaric Acid, 637, 654
Isosaccharine, 605, 620, 661
Isoserine, 393, 541
Isosuberone Oxime, 395
Isosuccinic Acid, 259, 490
Ester, Cyano-Imido, 6ia
Isothioacetanilide, 274
Isothiocarbimide, 466
Isothiocyanic Acid and Esters, 159, 466, 469
Isothiocyanuric Esters, 471
Isothiuram Disulphide, 450
Isotrichloroglyceric Acid, 408
Isotriethylin, 338
Isourea, Derivatives of, 446
Isouretin, 244, 283
Isouric Acid, 580
Isovaleraldehyde, 63, 201 314, 390, 522, 673
Isovalcraldoxime, 213
Isovaleric Acid, 258, 260, 620
Isovaleryl Halides, 271, 315
Isoxazoles, 216, 232, 344, 350, 854
Isoxaiolone Derivatives, 545, 547, 564, 567
Isoximes, 213, 394
Itabromopyrotartaric Acid, 500, 557
Itachloropyrotartaric Acid 500 557
Itaconanilic Acid, 516
Itaconic Acids, 65, 90, 516. 516
Derivatives, 516, 517, 518, 595, 611
Itadibromopyrotartaric Acid 601 .561
Itamalic Acid, 557
Derivatives, 558
JALAPIN, 619
Japan Wax, 262
KEFIR-LACTASE, 658
Keratin, 674
Kerosene, 78
Ketazines, 228, 628
Ketenes, 270, 474, 475, 488
Ketipic Acid. 349, 608
Ketoadipic Acid, Oximes of, 570
Keto-amines, 345
KetoazelaTc Acid, 571
Ketobrassidic Acid, 304
Ketobutyric Acid, 410
Keto-compounds. See also Oxo-compoundi,
and Ketone Compounds
Ketocyclobutane Tricarboxylic Ester, 61*
Keto-cycloparaffin Carboxylic Esters, 504
Ketoglutaric Acids, 568, 612
Ketohydroxystearic Acid, 302, 546
Keto-lactones, 543
Ketols, 340
Derivatives, 343
Olefine, 343
Saturated, 340
Ketomalonic Acid Group, 562
Keto-methyl-caprolactone Carboxylic Acid, 607
Ketone Alcohols, 228, 306, 340, 625
Nitrogen-containing Derivatives of the,
Aldehydes, 348, 526, 537, 629
Carboxylic Acids, 306
Di-, 546, 607, 656
Mono-, 436 et seq., 562, 607, 6ia
Tri-, 598, 655
Cyanhydrines, 379
Decomposition of Acetoacetic Ester, 415
of Oxalacetlc E«t*r, 546
of Dlacetyl Diizninoadlpic Ester (re-
duced), 655
704
INDEX
Ketone Nitriles, 418, 410, 420
Esters, and Derivatives, 418, 419, 420
Oximes, 410
Nitrogen Derivatives of, 418, 419
Phenylhydrazones, 228
Semicarbazones, 228
Kctones, 100, 103, 106, 124, 139. *92
Acetylene, 232
Alkyl Ethers of the, 225
Cyclic, 504
Halogen substitution products of the, 94,
221, 224, 226
Hydroxymethylene, 343
Olefine and Diolefine, 228
Oximes of Cyclic, 394
Nitrogen Derivatives of the, 226
Saturated,
Di-, 348
Hexa-, 647
Mono-, 216
Tetra-, 597
Tri-, 527
Sulphur Derivatives of the, 225
Ketopentamethylene Monocarboxylic Acid Ester,
505
Ketopentane Trioles, 620
Ketopimelic Acids, 570
Ketopiperidine, 396
Derivatives, 535
Trimethyl diethyl, 535
Ketopyrrolidone, Dimethyl, 421
Ketostearic Acids, 300, 304, 424
Ketosuccinic Acids, 564
Keto-trimethyl-dihydroisoxazole Oxime, 231
Ketovaleric Acid, 421
Ketovalerolactone Carboxylic Acid, 408
Ketoximes, 152 eiseq., 197, 227
Derivatives, 253, 345
Kjeldah's Method for determining Nitrogen, 8
Klarsel, 659
Kola Nuts, 590
LACTALBUMIN, 670
Lactamide, 378
Lactams, 36, 39, 305
Lactarius volemus, 625
Lactazams, 406, 416, 419, 567
Lactazones, 406, 416
Lactic Acid, 193, 247, 258, 313, 341, 382, 364,
389, 408, 528, 630, 633
Bacillus, 363
Derivatives, 366, 371
Fermentation, 362, 363, 365, 631, 660
Nitrile, 380
Anhydride, 367
Ester, Chlorocarbonate of, 430
Ethylidene Ester, 368
Lactides, 367, 385
Lactime, 39
Lactimide, 392
Lactimidohydrin, 378
Lactobionic Acid, 660
Lactone Carboxylic Acids, 492
Lactones, 310, 371 ft seq., 375
Lactose, 113, 624, 625, 631, 654, 660
Carboxylic Acid, 660
Derivative, 660
Lacturamic Ester, 443
Lactyl Acetyl Lactic Acids, 367
Ureas, 443, 444
Lactylplactic Acid, 367
Laevulinamide, 423
Laevulinic Acetic Acid, 570
Acids, 342, 397, 421, 423, 540, 609
Derivatives, 422, 423. 548
Aldehyde, 91, 348
Methylal, 348
Chloride, 423
Lasvulosan Trinitrate. 636
Lasvulose, 113, 239, 422, 620, 623, 630, 634, 635,
651, 659
Lanoceric Acid, 677
Lanolin, 265, 677
I.anopalmitic Acid, 677
Lauramide, 278
Laurie Acid, 223, 261, 262
Ester, 268
Aldehyde, 201
Laurinamidoxime, 283
Laurone, 223
Laurouitrile, 281
Laurus nobilis, 262
per sea, 625
Lauryl Ketoxime, 227
Lesser centaury, 363
Lead, Alkyl derivative of, 188
Leather, 673
Lecithin, 329, 530, 531, 666, 676
Leiocome, 663
Lemons, 610
Lepargylic Acid, 506
Leucic Acid, 366
Leucine, 165, 380, 390, 394, 443, 66)
Carbonic Anhydride, 437
Chloride Hydrochloride, 390
Derivatives, 392
Glycyl Aspartyl, 556
Leucyl, 392
Leuco-nitrolic Acid Salts, 154
Leucoturic Acid, 580
Leucyl Asparagine, 555
Leucine, 392
Pentaglycyl Glycine, 393
Proline, 543
Lichenin, 662
Lichens, 596, 662
Liebermann Nitroso reaction, 173
Light, Action of, 62
Lignite, 79, 492
Lignose, 664
Ligroine, 78
Linalopl, 125, 232, 423
Linoleic Acid, 301
Linolic Acid, 30
Lipase, 531
Liver Starch, 66a
Locust tree, 259
Lupeol, 677
Lupeose, 661
Lupins, 390, 635
Lupinus lutcus, 677
Lycine, 330, 387
Lycium barbarum, 387
Lymph-glands, 389
Lysalbic Acid, 670
Lysidine, 333
Lysine, 334, 390, 540, 542, 543, 667
Lyxonic Acid, 619, 620
Lyxose, 616, 619
MAGNESIUM Alkyl, 72, 103, 124, 133, 144, 147,
171, 184
Halides, 185, 189, 193, 217, 310, 316,
318, 329, 359. 365,417
" Etherates " 185
Alkyls, 184
Magnetic Rotary Power, 57
Maleiic Acid, 28, 31, 33, 34, 63. 86, 510, 511
Half Aldehyde of, 402
Haloid, 514
Ismerism of, 512
Substituted, 516 :5i8
Anhydride, 510
Anhydrides, Alkyl, 518, 519, 595
Chloride, 511
Mnlem Hydrazide, 511
Malemamic Acid. 511
Malei'nanil, 511
Malemanilic Acid, 511
Malelndianilide, 511
Malemimide, 511
Malemmethylamic Acid, 511
Malic Acid, 247, 499, «1. 561, 565
Derivatives, 556
Homologues, 421, 519, 556> 557
Acids, Amides of the, 553
Malonamide, 489
Derivatives, 489, 550, 577 599
INDEX
705
Malonanilic Acid Ester, Acetyl, 4x9
Malondiamidoxime, 489
Malondibydroxamic Acid, 489
Malonic Aldehydes, 847, 354, 401
Acid, 249, 256, 286, 296, 444, 487, 583
Chlorides of, 488
Derivatives, 402, 491, 549, 677
Glycolyl, 607
Acids, Halogen-substituted, 489
— — Nitriles ot, 489
• Carboxylic Ester, 592
• Derivatives, 306, 490, 491, 508 522,
550,614,615
Ester, 254, 268, 377, 487, 506, 566, 592, 599
Derivatives, 394, 395, 419, 489,495,
543, 550
Dicyanoacetoacetic, 655
• Methylene Compounds, 561, 613
Sodium, 615
Hydrazide, 489
Malononitrile, 489
Malonuric Acid Dialkyl, 577
Malonyl Chloride, 488
Guanidine, 576
Thiourea, 576
Urea, 444, 570, 583
Malt, 113
Germ of, 387
Maltase, 633, 658
Maltobionic Acid, 660
Maltobiose, 660
Mai tonic Acid, 649
Maltose, 113, 114, 625, 649, 660, 661, 663
Carboxylic Acid, 661
— Derivatives, 661
Manna, 624, 661
Manna-ash, 623
Mannide, 623
Mannitan, 623
Mannite, 623
Mannitol, 99,112,601, 628,627,631, 632, 633,683
Dervatives, 624
Mannitose, 623
Manno-amine, 624
Mannohepitol, 624
Mannoheptonic Acid, 631
Mannoheptose, 687, 651
Mannolactone, 653
Mannonic Acid, 624, 648, 649, 633
Lactone, 632
Mannononic Acid, 637, 652
Mannononose, 637,652
Manno-octilol, 625
Manno-octonic Acid, 637, 651
Manno-octose, 625, 687, 652
Mannosaccharic Acid, 623, 65S
Mannosaccharolactone, 653
Mannose, 624, 630, 631, 633, 631
Carboxylic Acid, 651
Derivative, 632
Mannosimine, 636
Maple, 658
Margaric Acid, 223, 261, 268
Aldehyde, 201
Margarine, 264
Marsh Gas, 71
Mass Action, Law of, 265
Meat, Decay of, 334
Extract, 456, 592
Melam, 473
Melamine, 472, 478
Melampyrin, 624
Melanurenic Acid, 473
Melasse, 387, 390, 669
Melecitose, 66 1
Melem, 473
Melibiose, 658. 661
Melissic Acid, 261. 268
Melissyl Alcohol, 122
Melitose, 661
Melitriose, 661
Melting-point, 46
Menthone, 37', 424. 493t 5<>3
• Oxime, 396
VOL. I.
Mercapto-aminopyrimidine, Ethyl, 574
Mercaptal Carboxylic Acids, 376
Mercaptals, 143, 200, 209, 617
and their Sulphones. 209
Dextrose, 634
Ethylene, 324
Rhamnose Ethyl, 619
Mercaptan Carboxylic Acids, 376
Mercaptans, 83, 142, 146, 824, 453
Glycerol, 530
Tellurium, 148
Mercaptides, 142, 144, 185
Mercaptol Carboxylic Acids, 376
Mercaptols, 143, 209, 220, 226, 229
Ethylene, 324
Mercapto-mercaptols, 229
Mercapto-oxypyrimidine, Methyl, 574
Acetone, 223
Mercurialis anua, 164
perennis, 164
Mercuric Cyanide, 242
Hydroxide, Ethyl, 188
Mercury Acetamide, 276
Alkyls, 187, 1 88
Iodides, 188
Allyl Iodide, 188
Diethylene Oxide, 320
Dipropionic Acid, 289
Ethanol Iodide, 320
Formamide, 239
Fulminate, 151, 249
Mercaptide, 143
Nitrate, Methyl, 188
Nitroacetic Ester, 380
Prophylene Glycol Iodide, 333
Merotropy, 38
Mesachloropyrotartaric Acid, 500
Mesaconanilide Acid Chloride, 516
Mesaconic Acid, 407, 420, 515, 516
Homologues of, 408, 516, 519
Mesaconyl Chloride, 517
Mesadibromopyrotartaric Acid, 501
Mesitalcohol, 230
Mesitene Lactam, 399
Lactone, 899, 571
Mesitonic Acid, 398, 483, 559
Derivative, 424
Mesityl Nitrimine, 231
Oxide, 91, 221, 225, 228, £29, 298, 342, 348,
423, 534^
Denvatives, 231, 342, 548
Mesitylene, 89, 221
Mesitylic Acid, 494, 498, 559
Mesodibromopyroracemic Acid, 297
Mesodinitroparamns, 154, 226
Mesoporphyrin, 675
Mesotartanc Acid, 28, 32, 34, 511, 600, 603, 604
Mesotartaronitrile, Diacetyl, 605
Mesoxalic Dialdehyde, 537
Acid, 444. 528, 489, 562, 572
Derivatives of, 563, 564
Mesoxalyl Urea, 578
Metacarbonic Acid, Esters of, 427
Metacrolein, 215
Metaforraaldehyde, 199
Metaformic Acid, 235
Metaldebyde, 199, 200
Metallo-Organic Compounds, 183
Metamerism, 25
Metapropyl Aldehyde, 201
Metapyroracemic Acid, 408
Metasaccharic Acid, 374, «68
Metasaccharine, 620, 621
Metasaccharopentose, 605, 620
Methacrylic Acid and Ester, 224, 297, 503
Anilide, 298
Methane, 64, 66, 67, 71, 198, 242, 258
Disulphonate Phenylhydrazone, Potassium,
Homologues of, 74
Tricarboxylic Ester and Derivative, 592
Methanol Piperidine, 613
Trisulphonate .Potassium, 434
2 Z
706 INDEX
Metharonic Acid, 151, 339
Methenyl (radical), 24, 233
— — Amidme, 244
— — Amidoxime, 244, 283
Acetic Acid, 489
Bis-acetoacetic Ester, 640, 6ro
Bis-acetyl Acetone, 536
Bis-malonic Ester, 615
Carbohydrazide,*448
Disulphpnic Acid. See Methionic Acid
Methine (radical), 24, 233
Tripropionic Ester, 594
Trisulphonic Acid, 210, 247
Methionic Acids, 210, 377, 434, 536
Anilides, 210
Methionyl Chloride, 210
Methose, 636
Methoxy-dimethyl-acetoacetic Ester, 546
Methoxyacetonitrile, 379
Methoxybutyronitrile, 380
Methoxycaffeme, 583, 591
Methoxycitric Acid, 611
Methoxycrotonic Ester, 418
Methoxylamine, 172
Methoxymesityl Oxide, 343
Methoxymethylene Glutaconic Ester, 561
Methyl Acetic Acids, 258, 260, 261, 268
Acetobutyl Alcohol, 342
Acetyl Thiocarbamate, 449
Urea, 442
Alcohol, 99, 109
Aldehyde, 197
Allantoms, 573, 583
— — Alloxan, 579
Ammonium Compounds, 164
— — Arsenic Compounds, 176, 177
Asparagine, 556
Azoic Acid, 171
Biuret, 446
Borate, 141
Bromide, 135
Butene Lactone, 398
Butyl Tetrazone, 171
Caprolactams, 396
Carbamic Ethyl Ester, 436
Carbamyl Chloride, 438
— Carbimide, 462
Carbinols, 118, 119, 120, 121, 370, 371
Carbonic Ester, 428
Carbotholic Acid, 274
Chloride, 135, 161
Chloroform, 95, 284
Chloro-Ke tones, 341, 350
Crotonic Acid, 298
Cyanamide, 472
Cyanide, 280
Cyanuric Acid, 464
Cyclohexanone, 375
Oxime, 396
Cyclopentanone Carboxylic Ester, 505
Decane Dicarboxylic Acid, 507
Diacetamide, 277
Diazoimide, 171
Dibarbituryl, 578
Dichloramine, 167
Diethyl Betame, 387
Glyoxime, 354
Hydantoln, 443
Melamine, 474
Peroxide, 355
Pinacone, 224
Semicarbazide, 447
Thetine, 377
Diiodamine, 167
Diketoncs, 349
Disulphldes, 144
Ether Glycollic Acid, 366
Ethers, 127, 129
Chloride, 140
Ethyl Ethylene Oxide. 318
Acetaldehyde, 201
Acetonitrile, 280
1 • Acetylene, 89
• Acroleln, 215
Carbin Carbino!, 114, 120
Methyl Ethyl Glycidlc Ester, 540
Glycollic Acid, 365
Nitrile, 379
Ethylene Glycol, 313
• Imine, 335
Fluoride, 133
Glyceric Acids, 539
Glycerol Aldehyde, 534
Glycidic Acids, 539
Glycocoll, 387, 456
Glycocyamide, 387
Glycocyamidine, 456
Glycocyamine, 456
Glycollic Ester, 366
Glyoxal, 348, 356, 630, 633
Derivatives, 348, 356
Glyoxalidine, 333
Glyoxime, 354
Guanidine Acetic Acid, 456
Guanidines, 455
Heptenone, 91, 282, 422
Glycol, 352
Heptonic Acid, 635
Hexyl Acetonitrile, 281
Hydantom, 387, 443, 456
Hydrazine, 168, 170
Hydrouracils, 444
Hydroxy-hydrosorbic Ester, 398
Hydroxyl Urea, 448
Hydroxylamine, 172
Hypochlorite, 141
Iodide, 136
Mercury, 188
lodochloride, 136
Indole, 667
Isoacetoxime Sodium Iodide, 227
Isobutyl Glyoxime, 354
Isobutylene Amine, 211
Isocitric Acid, 611
Isocyanate, 462
Isocyanide, 248
Isodialuric Acid, 574
Isopropyl Acetamide, 278
Carbinol, 119, 121
Ketoxime, 227, 345
Pinacone, 314
Isothiocyanic Ester, 470
Isourea, 446
Isouretin, 244
Isoxazoles, 354
Ketone, 224, 475
Derivatives, 224, 226, 227
Ketones, 223, 225, 232, 250
Ketoximes, 227
Lffivulinaldioxime, 355
Mercury Nitrate, 188
Methylene Amine, 211
Morphimethin, 329
Mustard, Oil, 470
Nitramines, 169
Nitrate, 137, 158
Nitric Ester, 137*
Nitroform, 284
Nitrolic Acid, 154, 243, 244, 248
Nitromalonic Ester, 549
Nitrosourethane, 437. See also Nitroso
methyl Urethane
Nitrourethane, 437
Nitrous Ester, 138
Nonyl Ketone, 223, 224, 261
CEnanthone, 223
Orthosilicate, 141
Oxalacetanil, 567
Oxalacetic Ester, 567
Oxamic Acid, 483
Parabanic Acid, 446, 675
Paraconic Arid, 298, 374, &51
Pentamethylene Glycol, 315
Pentenic Acid, 519
Penthlophen, 502
Phenyl Osa zones. 629
Osotriazole, 356
Pyridazolene, 424
Phosphinic Acid, 175
INDEX
707
Methyl Phosphite, 141
Piperidone, 396
Propane TricarboxyHc Acid, jgj
Propyl Acetaraide, 201, 278
Carbinol, 119, 121
Glyoxiine, 354
Purines, 584
Pyrazoles, 343, 858
Pyrazalone, 399, 416
Pyridazinone, 424
Pyridazolone, 424
Pyrrolidines, 335
Pyrrolidones, 396
Quinoline, 339
Semicarbazide, 447
Stannic Trihalides, 183
Stannonic Acid, 182, 183
Succinimide, 498
Sulphide, 143
Sulphobromide, 145
Sulphocarbamide, 470
Sulphochloride, 147
Sulphones, 146
Sulphonic Acid, 146
Anhydride, 147
Calcium Salt, 247
Sulphonyl Isocyanate .463
Sulphoxides, 145
Sulphuric Acid, 139
Tartrodinitrile, Acetate of, 550
Tartronic Acid, 409, 550
Telluride, 148
Tetrahydrofurfurane, 318
Tetramethylene Glycol, 315
Tetronic Acid, 420, 544, 545
Tetrose, 603, 619, 646
Thialdine, 209
Thiosemicarbazide, 454
Triacetonamine, 230
Trimethylene Glycol, 314
Urea, 441, 574
Uracil, 416, 674, 584
Uramils, 578
Urea, 440
Uric Acids, 582
Xanthic Ethyl Ester, 4=33
Xanthine, 589
— — Derivatives, 591
.jthylal, 205
[ethylamine, 184, 211
lethylaride, 169. 171
lethylene Aminoacetonitrile, 242, 386, 887.
See also Glycocoll
Bromide. 206
Chloride, 209
Cyanhydrin, 385
Cyanide, 489
Diacetamide, 277
Diacetate, 207
Diamine, 211
Derivatives, 277
Diethyl Sulphone, 209, 243
Diisonitramine, 154
Disulphonic Acid, 468. See Methionic Add
Diurethane, 436
Ethers, 205
Glycol, 199
Derivatives, 204, 207
Iodide, 80, 208, 246
Lactate, 367
Malonic Esters, 508, 613
Mannonic Lactone, 649
Succinimide, 499, 5*5
Sulphones, 209, 210, 243
Thiocyanate, 468
— Urea, 441
fethylenitan, 636
r Sthyl-heptane-3-ol-2,5,6-trione, 597
!thylimidodithiocarbonic Dimethyl Ester,
iethylimidothiobiazoline, 454
ethyl - mercapto - 5 - methyl - 6 - oxypyrimidine,
574
'icrococci, 631
Micrococcus aceti, 256
Milk, Albumin, 672
Casein, 672
Sour, 362
Sugar, 660. See also Lactosa
Mineral Acids, Esters of, 130
Oil, 77
Waxes, 79
Mixt. sulf. acida, 139
Molasses, 588, 659
Dry Distillation of, no
Molecular Volumes, 45, 46
• Weight, Determination of by the
chemical method, 10 ; from the vapour
density, n ; Victor Meyer's method, 12;
of substances when in solution, 13 ; by means
of Osmotic Pressure, 13 ; plasrnolytic method,
13 ; from the lowering of the vapour pressure
or the raising of the boiling point, 14 ; Beck-
mann's method, 15 ; from the depression of the
freezing point, 15; Beckmann's method,
Eykmann's method, 17
Monacetin, 530
Monaminothiocarboxylic Acids, 541
Moniodoacetic Acid, 288
Monoaminohydrocyanuric Acid, 474
Monoamino-hydroxyl-carboxylic Acids, 540
Monobromacetal, 203, £05
Monobromacetic Acids, 288
Monobromacetone, 224
Monobromethane, 135
Monobromethyl Ether, 287
Monobromo-asym.-dimethyl-succinic Acid, 556
Monobromocyanacetic Ester, 489
Monobromofumaric Acid, 514
Monobromoleic Acid, 301
Monobromomaleic Acid, 514
Monobromomalonic Acid, 489
Mono bromome thane, 135
Monobromomethyl Acetate, 207
Ether, 207
Monochloracetal, 201, 203. 205, 337
Monochloracetaldehyde, 208, 337
Monochloracetic Acid, 287, 320
Monochloracetone, 884, 417
Monochlorethane, 135
Monochlorether, 129
Monochlorethyl Acetate, 207
Alcohol, 117
Ether, 207
Monochlorhydrin, 532
Monochlorodiacetin, 530
Monochloro formic Acid, 238
Monochlorofumaric Acid, 514
Monochloromaleic Acid, 514
Monochloromalonic Acid, 489
Monochloromethane, 135
Monochloromethyl Acetate, 207
Ether, 206
Propyl Ether, 206
Monoethylin, 531
Monofluoracetic Acid, 288
Monofluoromethane, 134
Monoformal Tartaric Acid, 604
Monoformaldehyde Uric Acid, 58a
Monoformin, 237, 680
Monohalogen Acids, 288
Monohalohydrins, 529
Monoiodacetaldehyde, 203
Monoiodosuccinic Acid, 500
Monoiodocyanacetic Ester, 489
Monoiodofumaric Acid, 514
Monoiodomethyl Ether, 207
Monolactonic Acid, 560
Monomethyl Pseudouric Acid, 578
Thiourea, 452
Mononitroglycerines, 530
Mononitro-olefine, 148
Mononitroparaffins, 148, 151
Monoses, 113, 66 1
Monostearin, 530
Monosulphide, Thiuram, 450
Monosulphonic Acid, Dichloromethane, 347
Monothioacetyl Acetone, 350
7o8
Monothio-bis-malonlc Ester, 489
Monothiocarbonic Acids, 432
Monothiocyanuric Acid, 471
Monothioethylene Glycol, 3*4
Moringa oleifera, 262
Morphine, 164
- Bases, 330
Morpbolines, 330
Morphotropy, 44
Moss-starcb, 662
Mountain Ash, 305
__ Berries, 399, 55«
Mucedin, 670
Mucic Lactomc Acid, 654
Mucine, 636
Mucinogens, 672
INDEX
u cid, 303, 398, 515, 402, 535
Mucochloric Acid, 39.8, 432, 535
Muco-hydroxy-bromic Acid, 540
Muco-hydroxy-chloric Acid, 540
Mucoids, 672
Muconic Acid, 522, 606
Mucor mvttdo, 114
Mucous Fermentation, 631
Murcxan, 578
Murexide, 578, 680
- Reaction, 580, 581
Muscarine, 829, 34°
Muscles, Fluids of the, 363, 364
Musculin, 670
Mushroom, 625
Mustard. Oil of, 123
- Oil, 159, 166, 331, 46o, 489
-- Test, 469
- Seeds, Black, 470
Mutarotation, 634
Mycoderma aceti, 256, 34*
Myosin, 670
Myricyl Alcohol, 122, 262
— — Halides, 135, 136
- Ketoxirae, 227
-- Palmitate, 269
_ Ester, 268
- Aldehyde, 201
Myristica suritutmenv*, 53*
Myristin, *6a, *31
- Aldoxime, 213
Myristinidoxime, 283
Myristone, 223 „
Myristonitrile, 281
Myristyl Nitrate, 137
Myronate, Potassium, 470
NAPHTHA, 77
Naphthalene Sulphoalanme, 381
- Sulphoglycine, 388
Naphthenes, 78
Naringene, 619
Neftigil, 79
Neroli Oil, no
Nerve Tissue, 530
Nettles, Stinging, 236
Neuridine, 334
Neurine, 166, 829, 34*
Nickel Carbonyl, 247
Nitramines, 169, 192
Nitrate, Acetyl, 271
- Ethylene, 323
- Urea, 439
Nitric Acid, Esters of, 137
Nitrile Bases, 156, 165
Nitriles, 167, 212, 217, 240, 24*
- Acid, 240, 278, 374
Nitriloacetonitrile, 388
Nitrolomesityl Dioxime P, roxide, 231
Vitrilo-oxalic Esters, 484
NitrUotriacetic Acid, 388
Nitrimine, Mesityl, 231
trite, Acetyl, 271
troacetaldehyde Hydrazone, 150
troacetamide, 380
troacetic Ester, 380
troacetone, 344
- Anil, 344
troacetonitrile, 249, 380
troalcohols, 151, 328, 344
troaldehydes, 339
troalkyl Isonitramines, 154
.troazoparaf&ns, 150
itrobarbituric Acid, 577
itrobenraldehyde, 63
itrobeniene, 63, 148, 158
itrobenzoates, 401
itrobiuret, 445
itrobromacetamide, 380
itrobromalcohols, 339
itrobromoform, 152
itrobromomalonic Acid, 563
itrobutanes, 151
itrobutyl Glycerols, 151. »*'
Nitrobutyric Ester, 380
Nitrocarbamic Acid, 437
Nitrocelluloses, 530, 664
itrochloroform, 152, 429
itrocyanacetamide, 250
itrodibromacetic Acid, 380
Nitrodibromacetonitrile, 380
Nitrodibromomacetamide, 380
Nitrodimethyl Acrylic Acid, 399,
- Isomeric Ester, 380, 399
Nitroerythritol, 596
Nitroethane, 151
Nitroethyl Alcohol, 117, 828
- Urea, 441
Nitroethylisonitramme, 154
Jitro-fatty Acids, 380, 549
Nitroform, 88, 155, 235, 247, 4*9
rogn , 6 ; Dumas' method,
6 ; Kjeldahl's method, 8 ; Will and Varren
trap's method, 7
- Carbonyl, 447
- Stereochemistry of, 36
_ Tricarboxylic Di-ester Nitrile, 443
- Tricarboxylic Ester, 445
Nitrogylcerine, 264, 529
Nitroglycide, 533 ,
Nitroglycollic Acid, 368
Nitroglycollyl Glycollic Acid, 368
Nitroguanidine, 458
Nitrohydantoin, 442
Nitrohydrazones, 150
Nitrohydroxylarainic Acids, 194, *e3
Nitroisobutyl Glycol, 533
Nitroisobutylene, 151
Nitroisobutyric Acid, 380
Nitroisohexylene, 151
Nitroisopropyl Acetone, 231
- Alcohol, 328
Nitroiso valeric Acid, 260, 300
Nitroisoxazole, 535
Nitroketones, 344
Nitrolacetic Ester, 486
Nitrolactic Acid, 368
Nitrolamines, 345 , .,
Nitrolic Acid, 150, 152, 153, 234, 283
- Derivatives, 154, 249, 409
Nitrolomalonic Acid, 489
- - Ester, 380, 549
Nitrolomalonimidoxime, 489
Nitrolosuccinic Dimethyl Ester, 607
Nitromalic Ester, 553
Derivatives, 535
_ Dimethylamide, 549
Nitromalonyl Urea, 577
Nitromannitol, 623
Nitromethane, 151, 339, 429, 527
_ Disulphonic Acid, 247
2 -Nitro-2 -Methyl Butane, 151
Nitro-methyl-hydantom, 443
Nitro-uracil, 574
.
INDEX
709
Nitro-methyl-isoxazolone, 54*
Nitronic Acids, 150
Nitronitrosobutane, 153
Nitronitrosoparaffins, Meso-, 153
Nitronitrosopropane, 153
Nitro-octane, 151
Nitro-octylene, 151
Nitro-olefine Carboxylic Acids, 399
Nitro-olefines, 148, 151, 192, 328
Nitroparaffins, 148, 150, 158, 171, 192. 210
Nitrophthallic Acid, 120
Nitropropanol, 328
Nitropropionic Acid, 380
Nitropropyl Alcohol, 328
Nitropropylene, 151
Nitroprusside, Sodium, 243
Nitropyrimidine, Derivatives, 584
Nitrosamines, 163, 198
Nitrosates, Alkylene, 84, 846
Nitrosites, Alkylene, 84, 845
Nitroso-alkyl Hydroxylamines, 172
Nitrosocarbamic Methyl Ester, 437
Nitrosochlorethane, 283
Nitrosochlorides, Alkylene, 345
Nitrosodichloroethane, 283
Nitroso-diethyl-urea, 441
Nitrosodiethyline, 168
Nitroso-dimethyl-auiline, 159, 537
Nitrosodimethylene, 168
Nitroso-dimethyl-pyrrole, 537
Nitroso-ethyl-hydroxylamine, 173
Nitroso-fatty Acids, 381
Nitrosoguanidine, 458
Nitrosoisobutyric Acid, Nitrile of, 381
Nitrosolsopropyl Acetone, 231
Nitrosolic Acids, 234, 884
Nitroso-methyl-hydroxylamine, 173
Nitrojonitronic Acids, 152
Nitroso-octane, 153
Nitrosoparaffins, 152
Nitrosoparaldimine, 212
Nitrosopropyl Acetone, 231
Nitroso-tert.-butane, 153
Nitroso-tert.-pentane, 153
Nitrosoureas, 441
Nitrosourethane, 213, 487
Nitrosoximes, 284
Nitrosuccinaldehyde, 347
Nitrotartaric Acid, 604
Nitrosyl Chloride, 138, 163
Nitro-tert.-butyl Glycerine, 198, 527, 597
Nitrotetronic Acid, 544
Nitrotriiodoethylene, 151
Nitrouracyl, and Derivatives, 585
Nitrourea, 441
Nitrourethane, 213, 487
Nitrourethane Acetic Ester, 396
Nitrous Acid, Esters of, 137
Nonane, 74
Dicarboxylic Acid, 375, 5<>7
Non-drying Ofis, 302 ; Olive Oil, 302 ; Rape
seed Oil, 302
Nonitols, 637
Non-naphthene, 79
Nonohydric Alcohols, 623
Nonoic Acid, 861, 301
Ester, 268
Nonoses, 637
Nonyl Aldehyde, 193, 300
Ketoxime, 227
Propiolic Acid, 304
Nonylamine, 165
Nonylenic Acid, ig7, 291, «»»
Norcaradiene Carboxylic Esters, 404
Norisosaccharic Acid, 655
Nuclemic Acids, 573, 587, 672
Nucleo-albumins, 672
OcTACKTYt Maltose, 66l
Octadecane, 76
Octahydric Alcohols, 6*5
Octane, 77
Tesserakaidekacarboxylic Ester, 656
Octanolactam, 396
Octitols, 637 *
Octoacetyl Lactone, 660
Octobromacetyl Acetone, 351
Octochloracetyl Acetone, 351
Octodecylic Acid. 262
Octohydroxy-Aldehydes and -Ketones, 625
Octoic Acid, 261
Ester, 268
Octomethylene Diamlnc 335
Glycbl, 315
Octyl Alcohol, 128, 302
Glycerol Diethylin. 5j«
Mustard Oil, 470
Nitrate, 137
CEnanthaldoxime, 213
CEnanthamide, 278
CEnanthol, 801, 291, 30*
Hydrocyanide, 379
CEuanthone, 223
Cb'nanthyl Aldehyde, aoi
Nitrile, 280
CEnanthylic Acid, 261
(Enanthylidene, 89, 90
Oil, Mineral, 77
of Garlic, 123
of the Dutch Chemists, 38*
Rock, 77
Oils, Drying, 301
Fats, 264, 527, 530
Non-drying, 302
Technical application of the, 264
Olaeomargaric Acid, 302
Olefine Acetylenes, 91
Alcohols, 183, 124, 221
Aldehydes, 193, 814, 305, 346
Aminoketones, 345
Chlorhydrins, 84
Dicarboxylic Acids, 507
Glycol, Diacetate, 342
Glycols, 315, 340
Ketols, 343
Ketones, 228
Monocarboxylic Acids, 890, 300
Ozonides, 84
Pentacarboxylic Acids, 622
Polymerisation of, 84
Terpenes, 215, 422
Tetracarboxylic Acids, 615
Tricarboxylic Acids, 594
defines, 79, 186, 322
Oleic Acids, 124, 193, 890, 292, 800, 301, 506
Alcohol, 124
Oleln, 531
Olive Oil, 262, 364, 300, 302, 526, 531
Optical Properties, 51; colour; fluorescence;
refraction, 51 ; dielectric constant, 53
Resolution of Racemic Acid, 602
Rotary Power, 54
Orchids, 631
Orcinol, 425
Tricarboxylic Ester, 569
Ornithin, 540, 648, 667
Ornithuric Acid, 548, 667
Orsellinate of Erythritol, 596
Orthoacetic Derivatives, 884, 413
Orthoacetone Ethers, 225
Orthoaldehydes, 189, 204
Orthocarbonic Acid, Nitro-derivatives of, 429
and Esters, 426, 428
Sulphur derivatives of, 434
Orthoformic Acid and Esters, 141, 192. *•«> «44.
412, 56i, 594
Derivatives of, 244
Orthoke tones, 189
Alkyl Ethers of, 225
Ortholactic Acid, Chloride of, 364
Orthonitric Acid, Diacetyl, 271
Ortho-oxalic Acid and Derivatives, 482, 483, 56*
Orthophosphoric Acid, Esters of, 141
Orthopropionic Ester, 284
Orthothioformic Estert, 209, 835, *«•
710
INDEX
Orthoxazone, 406
Osamines, 617, 628
Osazones, 856, 629
Osmotic Pressure, Determination of the Molecular
Weight of substances when in solution, 13 ;
plasmolytic method, 13
Osotetrazones, 356
Osones, 629
Osotriazones, 356
Ovalbumin, 671
Ovomucoid, 672
Oxaiacetanilic Acid, 565
Oxalacetic Acid, 560, 564
Derivatives of, 565, 566, 567
Ester, 668, 655
Derivatives, 567, 612
Oxalacetoacetic Ester, 608
Oxalainidine, 486
Oxalan, 575
Oxalantin, 580
Oxaldehyde, 346
Oxalhydrazone, Bis-acetoacetic Ester, 484
Oxalhydroxyacetic Acid, 606
Oxalic Acid, 1 16, 250, 287, 312, 400, 401, 404,
408, 444, €80, 653, 659, 663, 664, 665
• Amides of, 483
• Derivatives, 349, 439, 482, 548
Ester, no, 161, 314, 481
Nitriles of, 484, 485
— . Thioamide, 486
Ureides of, 487
Hydrazide, 484
Derivatives, 380
Oxalimide, 483
Oxalines, 347
Oxalis, 480
Oxalisobutyric Ester, 567
Oxalobutyric Ester, 567
Oxalocitric Lactone Ester, 566, 594, 655
Oxalocrotonic Acid, 571
Oxalodiacetic Acid, 608
Oxalodiamidoxime, 486
Oxalodihydroxamic Acid, 486
Oxalodi-imide Dihydrazide, 486
Oxalo-dimethyl-acetoacetic Esters, 609
Oxalolaevulinic Acid, 609
Oxalomalonic Ester, 612
Oxalonitriie, 485
Oxalopropionic Ester, 567
Oxalosuccinic Ester, 612
Oxaluramide, 575
Oxaluric Acid, 487, 575
Oxalyl Bis-acetyl Acetone, 647
Chloride, 482
Diacetone, 597
Diglycocpll, 484
Dimalonic Acid, 655
Dimethyl Ethyl Ketone, 597
Guanidine, 576
Ureas, 442, 675
Oxamethanes, and Derivatives, 483
Oxamic Acid, 483
Oxamide, 483
Derivatives, 484
Oxamidines, 283
Oxamidoacetic Acids, 486
Oxamine Trimethyl Ortho-ester, 483
Oxaminic Hydrazide, 484
Oxanilic Acid, 483
Oxanilide Dioxime, 250
Oxazomalonic Acid, 564
Oxetones, 225, 374, 535
Oximes, 151, 152, 153, 212, 227
Oximide compounds. See Isonitroso-com-
pounds
Oximidoacetic Acid, 405
Oximidoacetone Dicarboxylic Acid, 569, 571
Oximidoadipic Esters, 570
Oximidobutyric Acid, 4x0
Oximido-fatty Acids, 381, 407, 410
Oximidoglutaric Acid, 568
Oximidoisocaproic Ester, 408
Oximidoketobutyrolactone, 544
Ozimidoketones, 353
Oximidomesoxalic Acid, 563
nitnle Ester, 563
Oximidomesoxalyl Ureas, 580
Oxiraidopiraelic Ester, 570
Oximidopropionic Acids, 405, 410, 55=;. 567
Oximidosuccinic Acids, and Esters, 51 /
Oximidotetronic Acid, 544
Oximidovaleric Acid, 408, 410
Oxo-compounds. See Koto-compounds
Oxonic Acid, 573, 584
Oxonium Oxygen, 127
Salts, 316. See also Etherates
Oxostearic Acid, 424
Oxy-amino-pyrimidine, 574
Oxycelluloses, C64
Oxychlorophosphines, Alkyl, 175
Oxycitraconic Acid, 605
Oxyfurazan Carboxylic Acid, 564
Oxyhasmoglobins, 674
Oxy-methyl-uracil, 574
Oxymucilage, 663
Oxyneurine, 330, 387
Oxypurine, 589
Amino-, 588
Oxytetraldine, 215, 339
Oxythiazole, Methyl, 469
Oxytriazine, Diphenyl, 447
Ozokerite, 79
Ozone, 339, 340, 347
Ozonides, 84, 91 ; diozonides, 90, 91, 204, 294,
300, 436
PALM Oil, 262, 264, 531
Palmitamide,273
Palmitic Acid, 122, 223, 261, 262, 268, 301, 531
Aldehyde, 201
Palmitin, 264
Palmitodistearin, 530
Palmitone, 223
Palmitonitrile, 281
Palmityl Amidoxime, 283
Ketoxime, 227
Pancreas, 389, 393, 589, 619, 660
Diastase, 658, 671
Pancreatic Decomposition, 542, 619
Pangium edule, 239
Paper, 657, 664
Papyotin, 677
Parabanic Acids, 442, 446, 487. 574, 575
Parabromacetaldehyde, 200
Paracasem, 672
Parachloralose, 634
Paraconic Acids, 197, 299, 375, 492, 517, 557,
558, 561
Paracyanogen, 486
Paraffin, Solid, 79
Carboxylic Acids—
Di-, 476
Hexa-, 656
Hepta-, 656
Peuta-, 622
Mono-, 235
Tetra-, 613
Tri-, 592
Paraffins, 69, 83, 132
Halides, 93, 94
Paraformaldehyde, 199
Paraglyoxal, Polymeric, 346
Paralactic Acid, 364
Paraldehyde, 199, 200, 203, 296, 534
Paraldimine, 212
Paraldol, 338
Param, 437
Paramucic Acid, 651
Paramylum, 662
ParanucleTns, 672
Parapropyl Aldehyde, 201
Parapyroacemic Acid, 408
Parasaccharine, 620, 622
Parasaccharonic Acid, 620
Parasorbic Acid, 305, 399, 604
Paratartaric Acid, 601
Paraxanthine, 589
INDEX
711
Paraxanthine Synthesis, of, 590
Parsley, 619
Pastinaca saliva, 122, 259 268
Paullinia sorbilis, 590 "
Peas, 554
Peat, 79
Dry Distillation of, 71
Pectin Substances, 663
Pectinose, 618
Pelargonamide, 278
Pelargonia roseum, 261
Pelargonic Acid, 261, 264, 300
• Anhydride, 273
Pelargonitrile, 281
Penicillium glaucum, 12, 364, 390, 538, 559, 602
Pentabromacetone, 224
Pentacarboxylic Acids, 622
Pentacetyl Gluconic Acid and Derivatives 617,
634, 649
Pentachloracetone, 224
Pentachloroglutaric Acid, 503
Pentachloropyridine, 520
Pentachloropyrrole, 497, 514
Pentadecane, 76
Pentadecatoic Acid, 261
Pentadecylamine, 165
Pentaerythritol, 198, 587
Derivative, 597
Pentaethyl Phloroglucinol, 223
Pentaglycerol, 528
Aldehyde, 534
Pentaglycol, 314
Pentaglycyl Glycine Ester, 392
Pentahydric Alcohols, 615
Pentahydroxyaldehydes, 625, 626
Pentahydroxycaproic Acids, 639
Pentahydroxydextroses, 626
Pentahydroxyhexoses, 626
Pentahydroxyketones, 625, 626
Pentahydroxymonoses, 626
Pentahydroxypimelic Acid, 651 651
Pental, 85
Pentallyl Dimethylaraine, 167
Pentamethyl Acetone, 224
Ethyl Alcohol, 122
Phloroglucinol , 223
Pentamethylene Chloride, 323
• Diamine, 211, 310, 331, 315, 334, 395, 502,
Dicarboxylic Acid, 507
Dicyanide, 506
Glycol, 315, 395
Imines and Imides, 331, 335, 836, 395,
502
Oxide, 817, 395
Tetramine,2ii
Pentane, 76
Dialkyl Sul phone, 226
Hexacarboxylic Ester, 656
Tetracarboxylic Acid, 613
Tricarboxylic Acids, 694
Pentane-triols, 528
Pentanitromannitol, 623
Pentapeptides, 391
Pentatriacontane, 77
Pentene Tricarboxylic Acid, 595
Pentenic Acids, 298, 299, 519
Pentenoic Acid, Methyl, 558
Penthiophen, Methyl. 502
Pentinic Acid, 420, 544
Pentitols, 815. 639
Pentosans, 662, 663
Pentoses, 615, 619, 616, 639, 67*
Pentosuria, 619
Pentyl Ethylene, 84
Pentylene Malonic Acid, 491
Oxide, 315, 317, 318
Pepsin, 667, 668, 671, 677
Peptides, Carbamic Acid Derivative? of the. 436
of the Aspartic Series, Di- and Iri -, 555
Peptone, 391. 671
Perbromacetone, 224
Perbrome thane, 96
Perbromethylene, 96
Perchloracetaldehyde, 288
Perchloracetic Methyl Ester Derivatives, a88,
Perchloracetyl Acrylic Ac.d, 426, 514
Perchlorethane, 92, 96
Perchlorether, 129
Perchlorethylene, 96, 97, 288
Perchloric Acids, Esters of, 141
Pcrchlorobenzene, 66, 92, 96
Perchlorobutadiene Carboxvlic Acid, los
Percblorodithiocarbonic Methyl Ester 444
Perchlorodithioformate Methyl 4*4. '
Percbloromesole, 98
Pcrchloromethane, See Tetrarhlorome thane
Perchloromethyl Ether, 127
Mercaptan, 432, 434
Pf rchloroputine Carboxylic Acid, 305
Perchlorous Acids, Ester of, 141
Perchloro vinyl Ether, 129
Peroxalate, Potassium, 481
Peroxide, Acetone, 224
Crotonyl, 296
Cyclodiacetone, 224
Cyclotriacetone, 224
Dibromoglyoxime, 250
Diethyl, 130
Dioxime, 608
Ethyl Hydrogen, 130
Fumaryl, 509
Glutaric, 502
Nitrilomesityl Dioxime, 231
Succinic, 496
Peroxides, Acid, 273
Aldehyde, 203
Alky] Hydrogen and Dialkyl, 129
Dialkyl, 129
Glyoxirae, 355
Perseitol, 624, 637, 651
Perspiration, 236, 259
Perthiocyanic Acid, 467, 461
Petroleum, 71, 77, 78, 82
Petrolic Acids, 79
Phaeophytin, 675
Pharaoh's Serpents, 467
Phase Rule, 56
Phasotropism, 38
Phenanthraquinone 63, 333
Phenanthrene, 62
Phenol, 140, 347, 552, 652, 667
Carboxylic Acids, 429
Glucuronic Acid, 652
Phenoxyacetal, 338
Phenoxy-amino-butyric Acid, 541
Phenoxybromobutyric Acid 541
Phenoxycapronitrile, 380
Phenoxyethyl Malonic Acid, 541
Phenyl Acetic Acid. 667
Alanine, 667
Asparaginanil, 511
Azoethyl, 214
Azoformaldoxime, 403
Azoimide, 509
Butyrolactam, 395
Cyanate, 564
Diazoimide, 169
Glucoside, 634
hydrazido-chloride, Oxalic Esters, 486
Phenylamido-dimethyl-pyrrole, 356
Phenylene Diamine, 349
Phenylhydrazone Dimethyl Laevulinic Acid, 424
Mesitonic Acid, 424
Phenylhydrazones, Ketone, 228
Phenylhydrazonomesoxalic Acid and Deriva
tives, 564
Phenylimido-oxalic Methyl Ester .486
Isouretin, 244
Methyl Pyrazolone, 304, 416, 419
Pyridazone Carboxylic Acid, 6o7
Orthopiperazone, 498
Pseudouric Acid, 578
Succinimide, 498
Ureldo-Acids, 384
Uric Acid. 584
Phenylpyrazolone Acetic Acid, 569
INDEX
Phenylpyraiolone Carboxylic Acid and Deriva-
tives, 567, 608
Phenyltriaaole Dicarboxylic Ester, 523
Phlorogluconol, Carboxylic Ester, 488
Phorone, 91, 221, 225, 228, 229, 230, 537,
571
Phoronic Acid, 571
Phosgene, 63, 245, 256, 417, 428, 430
Phosphines, 173, 174, 176
Phosphinic Acids, 141, 173, 174, 175
Oxides, 173, 174, 175
Phosphonium Bases and Derivatives, 173, 174
Phosphoacids, Alky], 173, 174. i75, 196
Phosphoric Acid, Esters of Ortho-, 141
Phosphorous Acids, 141, 175
Phosphorproteins, 672
Phosphorus Bases, 173
Determination of, 8
Phototropy, 63
Phthalic Acid, 159
Phthalimidoacetone, 344
Phthalimidobromopropyl Malonic Ester, 541
Phthalimidobromovaleric Acid, 542
Phthalimido-alkyl Malonic Esters, 394, 395,
Phthalimidomalonic Ester, 550
— — Cyanopropyl, 560
Phthalyl Aminobutyric Nitrile, 394
Glycocoll Ester, 385
Phycitol, 596
Phyllogen, 675
Phylloporphyrin, 675
Physeter macrocephalus, 268
Phytochlorine, 675
Phytorhodin, 675
Phytosterol, 677
Pichurim Beans, 269
Picoline, 215, 528
Dicarboxylic Acid, 409
Picric Acid, 429
Pimelic Acid, 322, 493, 506, 613
Diacetodimethyl, 610
Ketone, 504
Nitrile, 334
Pimelimide, 498
Pinacoline, 216, 223, 219, 224, 314, 379, 408
Oxime, 165, 227
Pinacolyl Alcohol, 85, 122
Sulphocarbamide, 452
Pinacone Formation, 352
Transformation, 83, 314
Pinacones, 63, 216, 220, 224, 311, 81S
Pine-apple Oil, Artificial, 268
Pine Needles, 236
Pinene, 558
Pinus Jeffrey*, 77
. larix, 661
sabiniana, 77
Pipecoline, 331
Piperazines, 836, 337, 391, 384
Pipercyonium Halides, 331. 836
Piperic Acid, 601
Piperidic Acid, 394
Piperidine, 90, 321, 331, 886, 502
Derivatives, 337, 340, 396, 535, 6*3
Pyperidene Oxide, 340
Piperidone, 396
Carboxylic Acid, 560
Piperidyl Ure thane, 394
Piperine, 336
Piperylene, 90
Pivallic Acid. See Trimethyl Acetic Acid
Pivaloi'n, 342
Plane Symmetrical Configuration, 33
Plant Mucus, 663
Plaster, 264, 265
Polarization, Rotation of the Plane of Optical,
Polyethylene Glycols, 313
Polyglycerols, 532
Polyglycollide, 287, 867, 549
Polymerism, 25
Polymerization, 63
of Formaldeh
yde, 199
Polymerization of the Cyanogen-Oxygen Com-
pounds, 460
of the Olefines, 84
Polymethacrylic Acid, 297
Polymethylene Derivatives, Cyclic, 33
Halides, 323
Polymorphism, 43
Polynitroparaffins, 155
Polypeptides, 390, 391, 543, 671
Esters, 403
Polysaccharides, 113, 661
Potasfio-antimonyl Tartarte, 603
Potassium A Iky Is, 184
Carbon Monoxide, 247
Cyanate, 461
Cyanide, 242
Ferrocyanide, 243
— — Isocyanate, 242, 461
Seltnocyanate, 467
Thiocyanate, 467
Potato Spirit, Manufacture of, 113
Powder, Smokeless, 530, 665
Primulaceee, 625
Procession caterpillar, 236
Proline, 390, 540, 642, 598, 667
Leucyl, 543
Prolyl Alanine, 543
Glycine Anhydride, 643, 673
Propalanine, 230
Propanal Disulphonic Acid, 348
Propane, 74, 76
Disulphonic Acid, 327
— — Pentacarboxylic Acid, 622 | [614
Tetracarboxylic Acid and Ester, 594, 613.
Tetrasulphonyl, Tetraethyl, 347
Tricarboxylic listers, 502. 681
Trisulphonic Acid, 530
Propargyl Alcohol, 125
Ethyl Ether, 129
Halides, 136, 137
Propargylamine, 167
Propargylic Acid, 803, 523
Aldehyde, 215, 354
Propenyl Alkyl Ketones, 228, 229
Glycollic Acid, 897, 422
Trichloride, 527
Propenylamine, 166
Propeptones, 669, 670
Propiobetalne, Trimethyl, 393
Propiolic Acids and Ester, 129, 295, 808, 304,
418
Aldehydes, 216, 347
Propionaldehyde (see also Propyl Aldehyde), 314
Propionaldoxime, 213
Propionacetal Malonic Acid, 402
Propionamide, 77
Propionic Acid, 258, 294, 303, 368, 4Q2, 528
—— — Derivatives, 401, 402, 406
— — and Ester, Formyl, 401, 402
— — Derivatives, 377, 397
Acids, Halogen, 288, 289
Aldol, 339
Anhydride, Hydroxy-mercury, 289
Esters, 194, 268
Peroxide, 273
Propionitrile and Derivatives, 280
Propionoin, 342
Propionyl Acetic Ester, 418
Acetoacetic Ester, 419, 548
Acetonitrile, 419
Azide, 278
Carbinol, 341
Cyanacetic Ester, 564
Cyanide, 409
Formamide, 409
Formic Acid, 397, 408
Halides, 270, 271, 3*5
Malic Ester, 553
Propionaldioxime, 355
Propionic Ester, 418
Pyroracemic Ester, 547
Propyl Acetoacetic Ester, 418
Acetic Acid, 258, 260
Acetylene Carboxylic Acid, 304
INDEX
7*3
Propyl, Acroleln, a 15
Alcohols, 114, 117, 529
Aldehyde, 117, 201, 218, 313. See also
Propionaldehyde
• Phenylhydrazone, 214
Aminovaleric Acid, 394
Barbituric Acid, 577
Bromide, 135
Butyrolactone, 375
Carbinol, 118
Chloramine, 167
Chloramylaraiae, 331
-Chloride, 134
Chlorophosphine, 173
Dichloramine, 167
Ether, 129
Iodide, 136
Isocyanide, 248
Methyl Carbinol Acetate, 367
Butyrctactone, 375
Methylene Amine, 211
Mustard Oil, 470
Nitramine, 169
Nitrate, 137
Nitrolic Acid, 154
Oxychlorophosphines, 175
Phospho-acid, Diethyl Ester, 173
Piperidone, 396
Pseudonitrole, 153
Silicoformate, 141
Sulphide, 144
Thiourea, 452
Zinc, 187
Propylamine, 164, 165
Propylene, 82, 85, 97, 117, 124, 527
Diamine, 333
Glycols, 813, 341
• Derivatives, 320, 324, 533
Halides, 822, 493, 527
Oxide, xx8, 222, 818
Pseudothiourea, 452, 458
Pseudourea, 440, 446
Sulphonic Acids and Derivatives, 147
Tetracarboxylic Acids, 613, 615
Propyl Glyceric Acid, 539
Propylidene Chloride, 206, 319
Diacetic Acid, 502
Propionic Acid, 299
Protagon, 531
Protalbic Acid, 670
Protaraines, 674
Proteins, 114, 541. 542, 554, 558, 657, 666
Decay of, 259, 33O, 390, 438, 439
Hydrolysis of, 383
Nucleo-, 672
Protocatechuic Acid, 607
Protococcus vulgaris, 596
Prozan-derivative, 459
Prussic Acid, 239
Pseudo-acids, 40
Pseudocyanogen Sulphide, 468
Pseudodiazoacetamide, 403, 406
Pseudodithiobiuret, 453
Pseudoforms, 38
Pseudofructose, 633
Pseudoionone, 232
Pseudoitaconanilic Acid, 515, 557
Pseudolutidostyril, 399
Derivatives, 419, 57*
Pseudomerism, 38
Pseudomucin, 672
Pseudonitroles, 150, 152, 153
Pseudonucleins, 672
Pseudosulphocarbamide, Derivatives of, 453
Pseudotheobromine, 589
Pseudotbiohydantom, 453
Pseudourea, 446
Pseudouric Acids, 578, 590
Ptomaines, 330, 331, 334i 667
Ptyalin, 658
Pule gone, 505
Pumpkins, 558, 559
Purine, 573, •••
Purone, 582
Purpuric Acid, 580
Putresceme, 838, 543
Pyknometer, 46
Pyran Dicarboxylic Acid, 609
Pyrazines, 336, 340, 344, 528
Derivatives, 330, 423, 543, 606
Pyrazoles, 88, 170, 213, 216, 232, 304, 344, 350,
858, 53.5, 544, 598
Derivatives, 343, 537, 547, 598
Pyrazolmes, 229, 231
Derivatives, 213, 293, 404, 509
Pyrazolone and Derivatives, 170, 303, 304, 403,
406, 416, 419, 523, 561, 567, 607, 608, 6ia
Methyl, 424
Pyridazinone, Methyl, 424
Pyridazone Carboxylic Acid, Phenyl Methyl, 607
Pyridine, 62, 69, 272, 336, 343, 347, 502, 5«,
648, 673
Dicarboxylic Acid, 6ia
Pyridone, 399
Pyrimidine and Derivatives, 280, 282 417, 453,
Pyrro^diazoles, 536, 344
Pyrocatechin, 607
Pyrocinchonic Anhydride, 507, 818, 6x«
Pyrocinchonimide, 519
Pyroglutaminic Acid, 559
Pyromucic Acid, 402, 654
Derivatives, 650
Pyrone, 535, 621
Carboxylic Acids, 561, 571, 6ai
Dimethyl, 599
Pyroracemic Acids, 219, 247, 289, 349, 363, 388,
407, 408, 516, 519, 539, 550, 573, 603, 605, 607
Acid Derivatives, 219, 408, 410, 347, 599,
602, 650
Alcohol, 341
Aldehyde, 848, 363
Derivatives, 334, 335
Peroxide, 219
Pyrotartaric Acid, 498, 499, 501, 5 15, 516. 603, 607
Derivatives, 374,495,498,519, 520, 561
Pyroterebic Acid, 899, 374, 503
Pyrotritaric Acid, 351, 408, 548
Pyrrole and Derivatives, 318, 335, 343, 347, 351,
353, 497, 5", 559, 609, 654, 673
Pyrrolidine, 90, 885, 340, 396, 497
Carboxylic Acid, 542
Pyrrolidones, 395, 396, 497
Derivative, 559
Pyrroline and Derivatives, 335, 543
Pyrrolylene, 90
Pyrromonazoles, 347
Pyruvic Acid, 407
Pyruvyl, 599
Nitrile, 409
Ureide, 443
Pyruvil, 573
Pyruvyl Compounds, 409, 399
JARTENYUC ACID, 295, 297
jrcitol, 487
srcitrine, 619
linoline, 90
linones, 349, 510
linonoid Dyes, 579
salines, 349, 62 9
RACBMIC Acid and Esters, 28, 32, 34, 57, 303, 4°°.
401, 501, 5", *01, 6°8, 621, 654
Dimethyl, 408, 605
Bodies, 56
Radicals, 18, 24
Radish Oil, 470
Raffinose, 661
Rape-seed Oil, 301, 30*
Rapinic Acid, 302
Reaction, Velocity of, 266
Rearrangements, Intramolecular, 36, 333, 401,
446, 469, 470,498, 631,634
Reduction, Electrolytic, 65
Refraction, 31
714
Rennet, 672
Reptiles, Excrements of, 581
Residues, 24
Resin, Guaiacol, 215
Reversion (of sugars), 658
Rhamnitol, 616, 619
Rhamnohexitol, 624
Rhamnohexose, 624, 635
Rhamnonic Acid, 620
Rhamnose, 616, 619
Carboxylic Acid, 635, 646, 650, 654
Rhodanic Acid, 451, 453
Rhodeose, 619
Rhodinal, 215
Rhodophyllin, 673
Rhubarb, 551
Ribonic Acid, 620
Ribose, 619, 650
Ribotrihydroxyglutaric Acid, 621
Ricinelaidic Acid, 302
Ricinoleic Acid, 301, 302, 399, 424
Ricinostearolic Acid, 302, 547
Roccella Montagnei, 596
tinctoria, 507
Roccellic Acid, 507
Rock Oil, 77
Rongalite, 208
Rubeanic Acid, 486
Rue, Oil of, 224
Rum, 114
artificial, 238, 268
Rumex, 480
Ruta graveoletK, 224
Rye, 636
SACCHARATES, 633, 659
Saccharic Acids, 603, 620, 631, 633, 639, 641,649,
652, 653, 659, 660
Saccharimeter, 659
Saccharimetry, 657
Saccharine, 620
Saccharobiose, 658
Saccharobioses, 113, 657, 658
Saccharolactonic Acid, 654
Saccharomyces, 114
ceuvisia seu vini, 112
Saccharone, 621
Saccharonic Acid, 620, 621
Saccharose, 658
Saccharum officinarum, 658
Salep Mucilage, 631
Salicin, 626
' Pentamethyl, 634
Salicylic Acid. 408, 506
Salicylide-chloroform, 245
Saliva, 658, 660
Sallow Thorn, 551
Saponification, 104, 131, 251, 267, 277
Sarcolatic Acid, 288, 363, 364
Sarcosine, 887, 392, 456, 589
Anhydride, 392
Sauerkraut, 363
Sawdust, 480
Schiff s Bases, 383, 475
Reagent, 628
Schizomomycetes, 114, 118, 314, 528, 631
Scurvy grass, 470
Sea buckthorn, 551
Sebacic Acid, 299, 301, 302, 506
Derivatives, 334
Secalose, 635
Secretions, Animal, 236
Seeds of Plants, 531
Seignette Salt, 603
Selenetines, 377
Selenium Compounds, 145, 148
Selenocyanate, Potassium, 467
Selenocyanide, Ethylene, 468
Semicarbazide, 441, 446
Semicarbazones, 228, 231
Seminine, 631
Seminose, 631
Semi-oxaraazide, 484
INDEX
Serican, 540
Serine, 364, 390, 540, 541, 667, 568, 674
Phcnyl Cyanate, 541
Serum-albumin, 670
Serum-globulin, 670
Sesquimercaptol, 342
Shales, Bituminous, 79, 82
Dry Distillation of, 71, 79
Silicic Acids, Esters of the, 141, 181
Silicoformic Esters, 141
Silicon, Alkyl and Alkyl Halide Derivatives of,
180, 181
sec. Amine Derivatives, 168
Chloroform, i8r
Silicononane, 181
Silicononyl Compounds, 181
Silicopropionic Acid, 181
Silk Fibroin, 392, 540, 674
Gum (Silk Glue), 540, 674
Silver Cyanide, 242
Fulminate, 250
Sinamine, 452, 472
Sinapin, 329
Sinapis alba, 329
nigra, 470
Sincalin, 329
Sinapoline, 440
Skatole, 667
Smokeless Powder, 530, 665
Soap Manufacture, 527
Soaps, 131, 264
Sodium Acetoacetic Esters, 323, 355, 372, 413,
418, 486, 506, 509, 609, 610
Cyanamide, 458, 471
Ethenyl Tricarboxylic Ester, 622
— *• Ethoxide, 116
Ethyl Sulphite, 140
Sulphonate, 140
Ferrofulminate, 250
Formamide, 239
Fulminate, 250
Malonic Ester, 323, 372, 393, 486, 490, 494,
502, 505, 506, 507, 509, 550, 576, 613, 614
Nitroprusside, 243
Solubility, 50
Sorbic Acid, 299, 305, 398, 601
Ketones, 232
Sorbin Oil, 305, 399
Sorbose, 630, 635, 636
Bacterium, 341, 534, 597
Sorbus ancuparia, 305, 399, 551
Sorghum saccharatum, 658
Sorrel, Salt of, 480
Sour Milk, 362
Space-isomerism, 29, 33, 639
Specific Gravity, 45
Volumes, 45, 46
Spermaceti, 122, 262, 268, 506, 531
Spirits of Wine, in
Spiritus (stherjs nitrosi, 1 38
Spleen, 389
Spoon wort, 470
St. John's bread, 662
Stachyose, 661
Stocky s tuberifera, 66 1
Stannic Alkyl Compounds, 183
Stannonic Acids, 182, 183
Starch, 113, 114, 259, 480,625, 632, 649, 657, 662
Cellulose, 661
Gum, 663
Stearamide, 278
Stearic Acid, 74, 223, 261, 262, 300, 506, 531
Aldehyde, 201
Anhydride, 273
Stearin, 264, 531
Stearin-palmitic Lecithin, 531
Stearolactone, 375
Stearolic Acid, 301, 304
Stearone, 223
Stearonitrile, 281
Stearoxylic Acid, 804, 547
Stearyl Amidoxime, 283
Ketoxime, 227
Stereochemistry of Carbon, 19
INDEX
7*5
Stereochemistry of Nitrogen 16
of Sulphur, 36
of Tin, 36
Stereoisomerism, 29, 32, 214
Stibine Compounds, 179
Strain Theory of von Baeyer, 363
Strophanthus, 329
Stuffer's Law, 325, 327
Styryl Ethylamine, 340
Suberane, So
Suberic Acid, 322, 506
1 Azide, 334
Dialdehyde, 348
Suberone, 375, 504, 506
Substitution, Retrogressive, 93, 286 321
Succinaldehyde Dioxime, 355
Succinamic Acid, 497
Succinamides, 444, 496, 498
Succinanilic Acid, 497
Succinethylamic Acid, 497
Succinic Acid, 63, 81, 114, 402, 492, 516
Acids, Higher, 493, 494, 495, 5I8( 5i9j 520,
522, 551,556,557,561, 599
Halogen Substitution Products of, 499
Lactone, Aci-formyl, 561
Aldehydes, 91, 347, 402
Anhydride, 496
Carboxylic Ester, 592
Ester Derivatives, 561, 568, 603
Peroxides, 496
Succinimide, 335, 487
- — Derivatives, 497, 499, 557, 559, 568
ouccmodibromodiamide 498
Succinohydrazide, 498
Nitrile, Tetramethyl, 397
Succinonitrile, 499
Succinophenyl Hydrazide, 498
Succinyl Chloride, 374, 375, 495
Derivatives, 422, 423
Hydroxamic Acid, 499
Methylimide, 424
Peroxide, 496
Sucrose, 113, 114, 341, 594, 625, 649, 655, 658
Suet, 264
Sugar Beets, 587, 593, 66 1
Dry Distillation of, 218, 222
Inversion of Cane, 266
of Lead, 257
Sugars, 112, 480, 649, 656, 671
Sulphamide, Alkyl, 168
Sulphaminic Acids, 168
Sulphaminobarbituric Acid, 578
Sulphanhydrides. See Thio anhydrides
Sulphide Dicarboxylic Acids, 376
Sulphide-sulphones, 208
Sulphides, 143
Sulphine, 144
Compounds, 144, 324, 323
Sulphinic Acids, 147, 185, 325
Sulphite, Sodium Ethyl, 140
Cellulose, 664
Sulpho-. See also Thio-
Sulpho-acetic Acid, 326, 877
Sulpho-alanine, Naphthalene, 388
Sulpho-aminovaleric Acid, 394
Sulphocarbamic Acid, 449
Derivatives, 434
Sulphocarbamide, 451, 452
Sulphocarbimide, 466
Sulphocarbonic Acid, 432
Derivatives, 434
Sulphocarboxethyl Disulphide, 433
Sulphocarboxylic Acids, 377
Sulphocyanacetic Acid, 469
Sulphocyanic Acid, 466
Sulphocyanuric Acid, 471
Sulphoglycine, Naphthalene, 388
Sulphohydantom, 453
Sulphohydroxamic Acid, Benzene, 283
Sulpho-isobutyric Acid, 377
Sulphonal, 143, 209, 228
Sulphonates, 140, 170
Sulphone Carboxylic Acid, 377
Sulphones, 145, 208, 209, 225, 226, 245, 325
Sulphonic Acids, 146, 325
1 Derivatives, 159 454
— - Chloride, Trichloromethyl, 434
Sulphonium Compounds 144
Sulphosuccinic Acid, 553
Sulpho tetronic Acid, 544
Sulphothiocarbonic Acid, 433
Sulphourea, 451
Sulphoxides, 145
Sulphoxylates, Aldehyde, 20?
— — Ketone, 225
Sulphoxylic Acid, 147
Sulphur, 6
Atom, Asymmetric, 377
Determination of, 8
Stereochemistry of, 36
Sulphur-Ether, 127
Sulphuranes, 324, 325
Sulphuric Acid, Esters of, 38, 139
Glycol, 323
Ether-acids, 139
Sulphurous Acid, Esters of, 140
Synaptase, 658, 677
Syntonins, 670, 671
TAGATOSE, 630, 635, 636
Talitol, 624
Derivatives, 624
Tallow, 262, 264, 530, 531
Talomucic Acid, 647, 854
f Talonic Acid, 635, 650
Talose, 630, 635, 636
Tanacetogen Dicarboxylic Acid, 4gt
Tar, 79,82
Oils, 83
Tartar Emetic, 603
Tartaric Acid, Configuration of, 646
Acids, 25, 28, 31, 56, 63, 222, 364. 597,
599, 641, 653, 659
Tartarus emeticus or stibiatus, 603
Tartrazine, 608
Tartronic Acid, 489, 528, 549, 603
Derivatives, 544, 550
Semi- Aldehyde, 543
Tartronyl Ureas, 444, 577
Taurine, 325, 326, 331, 335, 541, 626
Bromomethyl, 533
Taurobetaine, 327
Taurocarbamic Acid, 327
Taurocholic Acid, ȣ6, 676
Tautomerism, 38
Tea, Paraguay, 590
Tellurium Compounds, 145, 148, 184
Teraconic Acid, 517, 518, 565
Teracrylic Acid, 299
Terebic Acid, 299, 374, 503, 517, 518, 658, 612
Terephthalic Acid, 402
Terpenes, 125, 215, 423, 424
Terpentine, 558
Terpenylic Acid, 299, 503, 658
Te trace tyl Diiminoputane, 647
Ethane, 597
Tetra-acetylene Dicarboxylic Acid, 523
Tetra-alkyl Ammonium Compounds, 165
Arsoniurn Compounds, 179
Diarsine, 176
Phosphonium Compounds, 173, 175
Stiboniura Compounds, 179
Tetrazones, 171
Tetrabromobutyric Aldehyde, 203
Tetrabromodiacetyl, 349
Tetrabromofonnalazme, 459
Tetrabromomethane, 429
Tetrabromoxalpdiacetic Ester, 608
Tetracarbonimide, 584
Tetrachlpracetone, 118, 224
Derivative, 229
Tetrachlorethane, 96
Tetrachlorethylene, 97
Tetrachlorocaffeme, 591
Tetrachlorodiacetyl, 349
Tetrachloroglutaconic Acid, 520
Tetrachloromethane. See Carbon Tetrachloride
716
INDEX
Tetrachlorophenyl Pyrrole, 498, 514
Tetrachlorophosphines, Alkyl, 175
Tetrachlorosuccinanil, 501
Tetrachloroxalodlacetic Ester, 608
Tetradecyl Butyrolactone, 375
Propiolic Acid, 304
Tetradecylic Acid, 262
Tetraethanyl Hexasulphide, 274
Tetraethyl Acetone, 223
Compounds. See also Tctra-alkyl Com-
pounds, and also parent substances
Oxalic Ester, 482
Succinic Acid, 495
Tetraethylium Iodide, 166
Tetrafluoromethane, 95, 426, 428
Tetrahydrocarvone, 375, 396, 424
Tetrahydrofurfurane, 318. 395, 655
Tetrahydronaphthalene Tetracarboxylic Acid,
613
Tetrahydropicoline, 343
Tetrabydropyridine Aldehyde, 340
Tetrahydropyrone Dicarboxylic Ester, Dimethyl,
621
Tetrahydropyrrolc, 90, 885, 395
Tetrahydrouric Acid, 582
Tetrahydroxyadipic Acids, 641, 653
Tetfahydroxyaldthydes, 616
Tetrahydroxyisovaleric Acid, 619, 620
Tetrahydroxymonocarboxylic Acids, 617, 619
Tetrahydroxypentane Carboxylic Acids, 620
Tetrahydroxyvaleric Acids, 810, 641
Tetraiodoethylene, 97
Tetraiodomethane, 429
Tetraldan, 338
Tetramethyl Acetone, 223
Compounds. See also Tetra alkyl Com-
pounds, and also parent substances
Dextrose, 633
Diaminoacetic Methyl Ester, 402
Diaminomalonic Ester, 563
• Diketocyclobutane, 290
Dinitroazoxymethane, 153
Ethyl Alcohol, 122
Ethylene, 83, 85, 122
Halides, 91, 322
— — Nitrosobromide, 322
Nitrosyl Chloride, 327
Oxide, 216, 314, 818
Fulgenic Acid, 522
Hydrazonium Iodide, 170
Hydroxyglutaric Acid, 560
Methane, 75, 76
Oxalic Ester, 482
Piperazonium Chloride, 331, 337
Pyrazine, 423
Pyrrolidine, 335
Succinanil, 498
Succinic Acid, 495
Nitrile, 397
Triaminopropane, 533
Uric Acid, 583, 591
Tetramethyl-cyclobutane-dione, 475
Tetramethyl-diamino-2-nitropropane, 533
Tetramethyl Dinitroethane, 155
Tetramethyl-methene-pentadiene, 91
Tetramethylene Carboxylic Acids, 292, 507, 614
Chloride, 323
Diaraine, 331, 338 395, 543
Dicyanide, 505
Glycol, 814, 370, 395
Imines, 835, 395
Nitrosamine, 335
Oxides, 316, 818, 395
Tetramethylium Iodide, 166
Tetranitroethane, 156
Tetranitromethane, 156
Tetranitrosaccharose, 660
Tetrapeptides, 391, 674
Tetrapropyl Succinic Acid, 495
Urea, 440
Tetrasuccinimide Tri-iodo-iodide, Potassium,
497
Tetrasulphide Acetic Acid, 377
Tetrazine Dicarboxylic Amide, 405
Tetrazpnes, Tetra-alkyl, 171
Tetrinic Acid, 341, 420, 544
Tetrolic Acid, 291, 296, 804
Tetronal, 226
Tetronic Acid, 544
Derivatives, 420, 545. 598. 607
Tetrose, 337, 897, 616
Tetroxan, Hexachlorodimethyl 20^
Thallium Alkyl Compounds, 1 88
Thiene, 164, 572, 575, 579, 580, 589, 590
Theobroma cacao, 589
Theobromic Acid, 262, 589
Theobromine, 588, 689. 590
Carboxylic Acid, 591
Theophylline, 572, 589, 590
Thetines, 377
Thiacetamide, 282
Thiacetic Acid, 273, 274, 536
Thialdine, 209, 212
Thiazole, 282, 420, 453, 469
Cyclic, 450
Thio-. See also Sulpho-
Thioacetals and their Sulphones, 2*9
Thio-acids, 273
Thioacetoacetic Ester, 543
Thioalcohols, 142
Thioaldehydes, 34, 208. 209
Thioallophanic Ester, 453
Thio-amino-butyric Acid, 542
Thio-amino-propionic Acid, 543
Thioammeline, 468
Thio-anhydrides, 273
Thiobarbituric Acid, 576
Thiobutyric Acid, 376
Thiocarbamic Acid. 449
Derivative. 450
Thiocarbamides, Acyl, 471
Alkyl, 469
Thiocarbonic Acids, 432
Derivatives, 431. 454
Thiocarbonyl Chloride, 432, v3-.
Thiocyanacetic Acid, 466, 469
Thiocyanacetone, 469
Thiocyanic Acid, 466
Derivatives, 239, 451, 471
Anhydride, 467
Esters, 432, 468, 471
Thiocyanodiamidine, 458
Thiocyanuric Acid, 471
Thiodiacetoacetic Ester, 417
Thiodialkylamines, 167
Thiodiazoles, 536, 543
Thiodibutyric Acid, 376
Thiodiethylamine, 167, 881
Thiodiglycol, 324
Thiodiglycollic Acid, 376
Anhydride, 376
Thiodilactylic Acid, 376
Thio-ethers, 143
Thioethyl Carbonic Ester, 432
Thioethyl Crotonic Acid, 419
Thioformethylimide, 243
Thioformic Acid, 243
Thioglycollide, 376
Thioglycollic Acid, 876, 453
Thiohydantom, 376, 453
Thio-imido-ethers, 234, 282
Thioisobutyric Acid, 376
Thioketones, 209, 220, 225
Thiolactic Acid and Derivatives, 408
Thiolactic Acids, 376
Thiolcarbamic Acid, 448
Ester, 449
Thiol-carbethylamme, 449
Thioraalic Acid, 553
Thionamic Acids, 168
Thion-carbonic Acid, 432
Thionic Acids, 273
Thion-carbon-thiolic Acid, 431, 481
Thionuric Acid, 578
Thionyl Chloride, 162, 168
Dialkylamines, 168
Diethyl Hydrazine, 170
Ethylamines, 162, !••
INDEX
717
Thionyl Ethylene Diamine, 333
Isobutylamine, 164
• Methylamine, 168
— — Tetralkyl Diamincs, 168
Thionylamines, 162
Thio-oxalic Acid, 486
Thio-oxypurine, 586, 589
Thiophene, 62, 69, 318, 347, 351, 496
Derivatives, 388, 654
Thiophosgene, 434
Thiopropionamide. 982
Thiopropionic Acid, 274
Thiopseudouric Acids, 578, 580
Thiopyrrolidone, 396
Thiosemicarbazide, 454
Thiosemicarbazones, 454
Thiosinamine, 452
Thiosuccinanil, 497
Thiosuccinanilic Acid, 497
Thiosulphonic Acids, 147
Thiotetralkyl Diamine, 167
Thiotolene, 422
Thiotriaminopyrimidine, 586
Thiouramil, 578
Thiourazole, 454
Thiourea, 420, 439, 451, 452, 574
Diallyl, 440
Guanyl, 458
Malonyl, 576, 577
Thiourethanes, 449
Thiouric Acid, 578
Thioveronal, 577
Thioxanthines, 582, 588
Thiuram Sulphides, 449, 450
Threose, 597
Thrombin, 670
Thujone, 423
Thymine, 573, 574, 672
Thymus Glands, 573
Tiglic Acid, 34, 292, 298
Aldehyde, 215
Ester, 298
Tin, Alkyl Compounds, 182, 183
Stereochemistry of ,36
Tobacco, 77, 55 1
Tolane Dihalides, 34
Toluene Sulphimide, 337
Toxalbumins, 667
Toxins, 667
Transformation, Benzylic Acid, 34*
Pinacone, 83, 314
Transposition, 89, 438, 467
Trehalose, 661
Triacetamide, 277
Tiiacetic Acids, 548
Triacetin, 530
Triacetohydrazide, 278
Triacetonamine, 230, 535
Triacetone Dialcohol, 534
Diamine, 280, 535
Dihydroxylamine, 231, 533
Anhydride, 231
Diurea, 441
Glucoheptitol, 625
Hydroxylamine, 535
Mannitol, 624
Triacetonylamine Trioxime, 345
Triacetyl Benzene, 343
Borate, 271
Trialkyl Ammonium Salts, 340
Cyanammonium Bromide, 473
Phosphine Oxide, 174
Trialkylamine Oxides, 172
Triallyl Melamlne, 472
Triamido phenol, 224
Triaminoguanidine, 459
Triaminopropane, 533
Triaminopyrimidine and Derivatives 576, 588
Triamyl SUicol, 181
Triazan Derivatives, 459
Triazene, Dicarboxylic Amide, 459
Dimethyl, 171
Triazole, 239
Triazolones. 404, 436
Tribenzoyl Methane, 40
Tribromacetic Acid, 288
Tribromacrylic Acid, 295
Tribromaldehyde, 203
Tribromethane, 96
Tribromethylidene Glycol, 203
Tribromhydrin, 529
Tribromobutyric Acid, 289
Tribromolactic Acid, 369
Nitrile, 497
Tribromomethyl Ketol, 643, 544
Tribromopropane, 136
Tribomopyruvic Acid, 408
fribromopyroracemic Acid, 246, 408
Tribromopyruvic Acid. 409. See Tribromo-
pyroracemic Acid
Tribromosuccinic Acid, 501
Tribromothiotolene, 425
Tributyrin, 530
Tricarballylic Acids, 306, 593, 594
Tricarbamidic Ester, 444, 445
Tricarbimide Esters, 464
Trichloracetal, 205
Trichloracetaldehyde, 201, 203
Trichloracetic Acid, 202, 287
Trichloracetoacetic Ester, 404, 421
Trichloracetoacrylic Acid, 425
Trichloracetyl Chloride, 97, 129, 288
Tetrachloracetone, 229
Trichlorocrotonic Acid, 425
Trichloracrylic Acid, 295
Trichlorethane, 95, 284, 337
Trichlorether, 129
Trichlorethyl Alcohol, 117, 652
Trichlorethylene, 97
Trichlorethylidene Glycol, 202
Malonic Ester, 508
Trichlorolactic Ester 368
Ure thane, 436
Trichlorobutyl Alcohol, 118, 651
Trichlorobutyraldebyde, 203
Trichlorobutyric Acid, 203, 289
Trichlorohydracetyl Acetone, 221
Trichlorhydrin, 529, 532
Trichlorisopropyl Alcohol, 106, 118, 364
Tiichlorocro tonic Acid, Trichloracetyl, 425
Trichlorohydroxybutyric Acid, 551
Trichlorolactamide, 581
Trichlorolactic Acid, 368, 549
Trichloromercuriacetaldehyde, 87
Trichloromethyl Paraconic Acid, 667, 618
Sulphonic Acid, 146, 434
Xanthine, 591
Trichlorophenomalic Acid 425
Trichloropropane, 529
Trichloropurine, 584, 587, 588
Trichloropyrimidine, 574, 576
Trichloropyroracemic Acid, 408
Trichlorosuccinic Acid, 501
Trichlorovalerolactic Acid, 369
Nitrile, 379
Trichlorovinyl Elkyl Ether, 482
Trichloryl Isocyanuric Acid, 466
Tricosane, 76
Tricyanic Acid, 463
Tricyanogen Chloride, 466
Tricyanotrimethylene Tricarboxyhc Esters, 489
Tricyantriamide, 473
Tridecane, 76
Tridecylamide, 278
Tridecyclic Acid, 261
Tridecylonitrile, 281
Triethoxyacetonitrile, 485
Triethyl Hydroxylamine, I7»
Iodide, 189
Triethylamine, 165
Derivative, 172
Triethylidene Disulphone Sulphide, 209
Trisulphone, 209
Triethylin, 531
Triformal, Mannitol, 624
Triformoxime, 213
Triglyceric Acid, 539
Triglycyl Carboxylic Acid, 437
7i8
INDEX
Triglycyl Glycine, 393
Trihalogen Acrylic Acids, 303
Trihalohydrins, 529
Trihydrocyanuric Acid, 474
Trihydroxyadipic Acids, 620, 621
Trihydroxybutyric Acid, 598
Trihydroxydicarboxylic Acids, 617, 621
Trihydroxyethylamine, 330
Trihydroxyglutaric Acids, 618, 619, 620, 621
Trihydroxyisobutyric Acid, 598
Trihydroxyvaleric Acids, 598, 620
Triiminobarbituric Acid, 576
Tri-iodoacetic Acid, 246, 288
Tri-iodoacetone, 246
Tri-iodoaldehyde, 246
Triisoamylene, 85
Triketokexanes, 537
Triketone Dicarboxylic Acids, 6ai
Triketopentane, 537
Trike to valeric Acid, 598
Trimercuric Acetic Acid, 481
Trimesic Acid, 303, 401, 615
Trimethyl Acetic Acid, 120, 247, 258, 280
Derivatives, 271, 268
Acetone Dicarboxylic Ester, 569
Acetonitrile, 280
Acetonyl Ammonium Chloride, 344
Acetyl Itamalic Anhydride, 558
Acrylate, 383
Benzene, 89
Carbimide, 464
Carbinol, 119
Carbylamine, 164
Diethyl Ketopiperidine, 535
Dihydropyi idine Dicarboxylic Ester, 212
Dioxymethoxypurine, 583
Ethyl Methane, 75
Ethylene, 83, 345
Derivatives, 327, 345
Hexadiene. 91
Hydracrylic Acid, 299, 370
• Hydrazonium Iodide, 170
Hydroxyadipic Acid, 560
Methane, 74
Pimelic Acids, 506
Propane Tricarboxylic Acid, 593
Propionic Betame, 389, 393
Pyrazoline, 228, 229, 231
• Succinanil, 498
— — Sulphonium Compounds, 145
Trimethylene Diamine, 333
Triose, 534
Uracil, 575
• UramU, 578
Valerobetalne, 394
Vinyl Acetic Acid, 375
Ammonium Hydroxide, 166
Trimethylamine, 19, 26, 165
Trimethyl-butadiene, 91
Trimethylene, 80
Bis-phthalimidomalonic Ester, 606
Carboxylic Acids, 292, 289, 404, 507, 550,
613, 614
Cyanides, 310- SOS
Diamine, 333
Dicyanosuccinlc Esw? 656
Dimalonic Ester, 613
Diphthalimide, 332
Disuccinic Acid, 614
Disulphide, 324
Disulphonic Acid, 327
Ethylene Diimine, 337
Nitrosite, 327
Toluene Sulphimide, 337
Glycols, 314
Deri
ivatives, 319, 324
Halides, 94, 289, 321, 822, 501, 614
• Imine, 335
Iminosulphonic Acid, 533
Mercaptal, Arabinose, 618
Dextrose, 634
Mercaptan, 324
Oxide, 222, 818
- Carboxylic Acid, 540
Trimethyleno Phenylhydrazine, 214
Sulphones, 209
Triamine, 211
Urea, 441
Trirnethylol-picoline, 199
Triketoheptane, 537
Trimyristin, 531
Trinitroacetonitrile, 155, 250, 485
Trinitrobenzene, 535
Trinitrochloro benzene, 162
Trinitroethane, 158, 284
Trinitrornethane, 155, 247
Trinitrophenol, 429
Trinitropropane, 530
Trinitrosotrimethylene Triamine, 211
Trinitrotrimethyl Propane, 344
Triolefines, 91
Triolein, 300, 531
Trional, 226
Triose, Trimethyl, 534, 616
Trioxan, Hexachlorodimethyl, 205
Trioximidopropane, 537
Trioxy-methyl-hydrouracil, 574
Trioxymethylene, 106, 199, 362, 461, 636
Tripalmitin, 531
Tripeptides, 391
Triphemyl Acetic Acid, 247
Tripropylamine, 172
Derivative, 172
Triselenide, Cyanogen, 467
Tristearin, 531
Tristearyl Borate, 271
Trisulphide Acetic Acid, 377
Trisulphone Acetone, 226
Trisulphones, 208, 342
Trisulphonic Acid, Formyl, 235
Propanone, 536
Trithioacet aldehyde, 209
Trithioacetone, 226
Tri-thio-bis-malonic Ester, 489
Trithiocarbonic Acid, 431, 433
Trithiocarboxylic Diglycollic Acid, 434
Trithiocyanuric Esters, 474
Trithiodibutyrolactone, 376
Trithioformaldehyde, 209
Triurea, Cyanuric, 465
Tropelne, 328
Truxillic Acid, 63
Trypsin, 667
Tryptic Digestion, 392, 543
Tryptophane, 406, 667
Turanose, 66 1
Turpentine Oil, 299, 492, 516, 518, 538
Type Theory, 272, 287
Tyrosine, 57, 390, 667, 674
UNDECANA&, 201
Undecane, 76
Undecanonic Acid, 424
Undecenylamine, 167
Undecolic Acid, 299, 304 424
Undecylamine, 165
Undecylenic Acid, 201, 299, 302, 304
Undecylenol, 124
Undecylic Acid, 261, 262, 539
Uracil Carboxylic Ester 567
Uracilimide, 574
Uracils, 444, 573, 672
Uramido-crotonic Ester, 585
Uramil, 444, 578, 580, 586
Uraroles, 447, 448
Urea, 25, 244, 250, 347, 428, 432, 488, 447, 461,
485, 542, 581
Ureas, Alkyl, 440
Azocyanide, 447
Chlorides, 430, 437
Compound, 160
Cyanacetyl, 576, 590
Cyclic Alkylene, 440
Hydrazine Derivatives of, 448
Derivative of Diacetonainine, 230
Guanyl, 457
Hydroxyl, 448
INDEX
719
Ureas, Malonyl, 677, 578, 579
Mesoxalyl, 578
Oximidomesoxalyl, 580
Sulphur-containing Derivatives of, 448
Tartronyl, 577
Ureldes, 384, 441, 442, 487, 571, 572, 575
Urethanes, 394, 485, 437, 577
Uric Acid, 336, 416, 455, 545, 572, 575 578, 581,
583, 587, 591
Synthesis of, 585
Urine, in, 333, 573, 619
Urobutyl Chloralic Acid, 203, 658
Urochloralic Acid, 202, 652
Urotropin, 210
Uroxanic Acid, 584
Uvic Acid. 408
Uvitic Acid, 408
Uvitonic Acid, 409
VALERALDEHYDE, 201
Valeramide,277
Valeriana officinalis, 260
Valeric Acid, 258, 280
Derivatives, 402, 424, 619, 641
Esters, 268
Valerobetalne, Trimethyl, 394
Valeroin, 342
Valerolactam, 396
Valerolactone, 374, 375, 559, 620
Derivatives, 378, 422, 559, 560, 598, 607,
612
Valeronitrile, 280
Valeryl Chloride, 271
Thiocarbimide, 471
Valerylene, 89
Valine, 889, 667
Vapour Density, Determination of the Molecular
Weight, ii
— — Pressure, Determination of the Molecular
Weight from the lowering of the, 14
Vaselines, 79
Vegetable Ivory Nut, 631
Veronal, 491, 577
Vetch Seeds, 455
Vetches, 554, 558, 580
Vicia faba minor, 580
saliva', 580
Vinaconic Acid, 55°
Vinasse, 165, 554
Vinegar, 256, 374
Vinyl Acetic Acid, 291, 297, 299, 539
Anilide,298
Acetonitrile, 297
Acrylic Acid, 305
Alcohol, 37, 128
Alkyl Ketones, 228, 229
Vinylamine, 166
Cyanide, 294
. Diacetonamine, 230
Ethers, 129
Ethylene Mercaptan, 324
Glutaric Acid, 522
Glycollic Acid, 397
Halides, 95, 97
Hydroxypivalic Acid, 39*
Hydroxypivalic fl
Mustard Oil, 144
Vinylamine, Sulphide, 144
Sulphonic Acid, 147
Trimethyl Ammonium Hydroxide, 329
Vinylidene Oxanilide, 349
Violuric Acid, 563, 680
Virginia Creeper, 362
Viscose, 664
Vitellin, 670
Volemitol ,625
WALDEN'S Inversion, 55, 364, 389, 500
Wandering, Atomic. See Intramolecular Atomic
Rearrangement
Water of Crystallisation, 44
Wax, Chinese, 122
Waxes, 268, 269
Mineral, 79
Wheat, Germ of, 387
Whey, 660
Whitethorn, 164
Wood, 79
Distillate from, 164
Dry Distillation of, 71
Fibre, 664
Oil, Japanese, 302
Spirit, 109, 222, 257, 267
''inegar Process, 257, 374
Wool Fat, 265
Spii
Vim
XAKTHANE Hydride 467
Xanthates, 433
Xanthic Acetic Acid, 433
Xanthine, 572, 586, 587, 688
Homologous, 590, 591
Xanthochelidonic Acid, 621
Xanthogenamic Acid, 449
Xanthogenamides, 449
Xanthogenic Acid Ester, 432, 438
Xanthophanic Acid, 547
Xanthophyll, 676
Xanthoproteln Reaction 669
Xanthorhamnine, 619
Xanthosuccinic Acid 553
Xanthoxalanil, 565 '
Xeronic Acid, 516, 519
Xylamine, 616
Xylitol, 616, 619, 621
Xylochloral, 619
Xylonic Acid, 618, 619, 620
Xyloquinone, 349
Xylose, 363, 597, «1». 621, 663
Carboxylic Acid, 650
Xylosimine, 636
Xylotrihydroxyglutaric Acid, 620, 621
Xylylene Bromide, 613
YEAST, 112, 394, 528, 552, 573, 632, 637, 663
ZINC, Alkyl Derivatives of, 186, 187, 256, 269
Alkyl Synthesis, 72, 83, 105, 217
Fulminate, 250
Zymase, ill, 677
END OF VOL. I.
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