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AMERICAN

Chemical JOURNAL

EDITKD BY

IRA REIVISEN

PROFESSOR OF Chemistry in the Johns Hopkins University.

Vol. XXIII. January-June. 1900.

BALTIMORE : THE EDITOR.

The Chemicai. Publishing Co., Printers,
Easton, Pa.

CONTENTS VOL. XXIII.

No. I.

Contribution from the Kent Chemical, Laboratory of the
University of Chicago :

On the Molecular Rearrangement of o-Aminophenylethyl Car-
bonate to o-Oxyphe7iylurethane . By James H. Ransom . i

Diazocaffeine. By M. Gomberg 51

The Action of Ethyl Iodide on Tartaric Ester and Sodium

Ethyi,aTE. By John E. Bucher 70

NOTE.
Improvements in the Manufacture of Sulphuric Acid . . .83

REVIEWS.

The Soluble Ferments and Fermentation 86

Einfiihrung in die Chemie in leichtfasslicher Form . . . .88

No. 2.

On Some Abnormal Frekzing-point lyOWERiNos Produced
by Chlorides and Bromides of the Alkaline Earths.
By Harry C. Jones and Victor J. Chambers . ... 89

Contributions from the Chemical Laboratories of the
Massachusetts Institute of Technology :

XXIII. — The Preparation of Pure Tellurium. By James
F. Norris, Henry Fay, and D. W. Edgerly . . . 105

XXIV. — The Reduction of Selenitim Dioxide by Sodium
Thiosulphate. By James F. Norris and Henry Fay . 119

Action of Picryl Chloride on Pyrocatechin in Pres-
ence OF Alkalies. By H. W. Hillyer .... 125

Contributions from the Chemical Laboratory of the
Rose Polytechnic Institute :

XVII. — Camphoric Acid. By William A. Noyes . . 128

Contributions from the Sheffield Laboratory of Yale
University :

LXXIII.^ — On the Rearrangement of Imido-esters . By
Henry L. Wheeler 135

The Double Halides of Antimony with Aniline and the

Toluidines. By Howard H. Higbee 150

On the Rancidity of Fats. By Iskar Nagel . . . .173

55149

iv Contents.

NOTE.
The Wax of the Bacillariaceae and Its Relation to Petroleum . 176

OBITUARY.

Johann Carl Wilhelm Ferdinand Tiemann 178

REVIEWS.
Theoretische Chemie i79

No. 3.

Contributions from the Chemicai, Laboratory of Corneli.

University :

Anethol and Its Isomers. By W. R. Orndorff and D. A. Mor-
ton .... 181

The Supposed Isomeric Potassium Sodium Sui^phites. By Geo. S.

Fraps 202

Condensation Compounds of Amines and Camphoroxalic Acid.

By J. Bishop Tingle and Alfred Tingle 214

A Method for the Determination of thb Mei.ting-point. By M.

Kuhara and M. Chikashigd 230

The Symmetrical Chloride of Paranitroorthosulphobenzoic

Acid. By F. S. Hollis 233

Contribution from the Kent Chemical Laboratory of the

University of Chicago :
Stereoisomers and Racemic Compounds. By Herman C. Cooper 255

OBITUARY.

Carl Friedrich Rammelsberg 261

NOTES.

Polonium and Radium 262

Asymmetric Optically Active Nitrogen Compounds .... 265

REVIEWS.

Les sucres et leurs principaux d^riv^s 267

Modes Opdratoires des essais du Commerce et de I'industrie . . 267

Water and Water Supplies 268

Outlines of Industrial Chemistry 268

Introduction to Physical Chemistry 269

A Text-book of Physical Chemistry 270

Optical Activity and Chemical Composition 271

A Short History of the Progress of Scientific Chemistry in Our Own

Times 271

The Kinetic Theory of Gases 272

Contents. v

The Compendious Manual of Qualitative Chemical Analysis of C. W.

Eliot and F. H. Storer 273

Descriptive General Chemistry 274

The Arithmetic of Chemistry 275

Experimentelle Einfiihrung in die unorganische Chemie . . . 275

Qualitative Analyse unorganischer Substanzen 275

Les Parfums Artificiels 275

No. 4.

The Ei,ectrical Conductivity of Liquid Ammonia Solutions.

By Edward C. Franklin and Charles A. Kraus .... 277

On the Cause of the Evolution of Oxygen when Oxidizable
Gases are Absorbed by Permanganic Acid. By H. N. Morse

and H. G. Byers 313

Contribution from the Chemical Laboratory of Wesleyan
University :

Absorption Apparattis for Elementary Organic Analysis. By
Francis Gano Benedict ........ 323

The Elementary Aiialysis of Organic Substances Containing
Nitrogen. By Francis Gano Benedict .... 334

Contribution from the Chemical Laboratory of the Univer-
sity OF Utah :

An Apparatus for Determining Molecular Weights by the
Boiling-point Method. By Herbert N. McCoy . . 353

REVIEWS.

Elementary Chemistry 361

Victor von Richter's Organic Chemistry, or Chemistry of the Carbon
Compounds 362

No. 5.

Preparation and Properties of the So-called "Nitrogen

Iodide." By F. D. Chattaway and K. J. P. Orton . . .363

The Action of Reducing Agents upon Nitrogen Iodide. By

F. D. Chattaway and H. P. Stevens 369

Contributions from the Chemical Laboratory of Harvard Col-
lege:

CXVII. — On Certain Colored Substances Derived from Nitro
Compounds. By C. Loring Jackson and F. H. Gazzolo . 376

The Solution-tension of Zinc in Ethyl Alcohol. By Harry C.

Jones and Arthur W. Smith 397

$

vi Contents.

Contribution from the Kent Chemicai^ Laboratory of the Uni-
versity OF Chicago :

Notes on Lecture Experiments to Illustrate Equilibrium and

Dissociation. By Julius Stieglitz 404

A Contribution to the Knowi,edge of Tei^lurium. By F. D.

Crane 408

Contributions from the Chemical Laboratory of Cornei^l Uni-
versity :

The Constitution of Gallein and Coerulein. By W. R. Orn-

dorff and C. E. Brewer 425

Permanganic Acid by Electrolysis. By H. N. Morse and J. C.

Olsen 431

On Chlorine Heptoxide. By Arthur Michael and Wallace T. Conn. 444

OBITUARY.

Dr. Guillaume Louis Jacques de Chalmot 447

NOTES.

Gadolinium 447

On Inorganic Ferments 449

REVIEWS.

A System of Instruction in Qualitative Chemical Analysis . . 451

Determination of Radicles in Carbon Compounds .... 451

Additions 452

No. 6.

Contributions from the Sheffield Laboratory of Yale Uni-
versity :

LXXIV. — Researches on the Sodium Salts of the Amides. By

Henry L. Wheeler 453

Contribution from the Division of Chemistry, U. S. Depart-
ment OF Agriculture :
Estimation of Alkali Carbonates in the Presence of Bicarbonates.

By Frank K. Cameron -47^

Contributions from the Chemical Laboratories of the Massa-
chusetts Institute of Technology :
XXV. — On the Isomorphism of Selenium and Tellurium. By
James F. Norris and Richard Mommers .... 486

Contributions from the Chemical Laboratory of Harvard Col-
lege :

CXVIII. — Note on the Constitution of Diparabrombenzyl-
cyanamide. ByC. Loring Jackson and R. W. Fuller . . 494
On the Effect of Very Low Temperatures on the Color of
Compounds of Bromine and Iodine. By J. H. Kastle . . 500

Contents. vii

On the Supposed Allotropism of Phosphorus Pentabromide.

By J. H. Kastle and L. O. Beatty . . . . • . .505

Contribution from the Chemical Laboratory of Hobart Col-
i,EGE :

On the Action of Nitrous Acid on Ethyl Anilinomalonate . By
Richard Sydney Curtiss ....... 509

On a Minimum in the Moi.ecui.ar L,owering of the Freezing-
point OF Water, Produced by Certain Acids and Sai.ts. By
Victor J. Chambers and Joseph C. W. Frazer . . . -512
REPORT.
The Year's Adyiance in Technical Chemistry 520

REVIEWS.
The Theory of Electrolytic Dissociation and Some of Its Applications 529
Traits El^mentaire de Mecanique Chimique Fondle sur la Thermo-

dynamique ........... 531

Legons de chimie Physique ......... 531

Errata 532

Index 533

Vol. XXIII. January, 1900. No. i.

AMERICAN

Chemical Journal

Contribution from the Kent Chemical Laboratory of the University of Chicago.

ON THE MOIvECUIvAR REARRANGEMENT OF ^-AM-

INOPHENYLETHYL CARBONATE TO t?-OXY-

PHENYIvURETHANE.'

By James H. Ransom.

On reducing ^-nitrophenylethyl carbonate,

0,NC,H,OCOOC,H„

with tin and hydrochloric acid in alcoholic solution, according
to Beiider,^ a white crystalline compound (melting-point 95°,
as given by Bender) separates out of the acid solution.
Analysis gave figures agreeing with the composition of the
expected reduction-product, aminophenyleth^d carbonate,
H.^NC„H^OCOOC,^Hj,, and this constitution has been ascribed
to the compound in spite of the striking absence of basic
properties. The seeming contradiction between properties
and constitution led Professor Stieglitz, who recently had oc-
casion to use the substance in connection with an investiga-
tion with Dr. H. N. McCoy, ^ to suspect that after the reduc-
tion of the nitro compound to an amine base, a molecular re-
arrangement of the latter produces Bender's body. Such a

1 See a preliminary report : Ber. d. chem. Ges., 31, 1055.

2 Ber. d. cheru. Ges., 19, 226S.
s This Journal, 21, iii.

2 Ransom.

molecular rearrangement could occur in one of the following
ways :

/OCOOC.H, yOs. /OH

CeH,/ --^ C,h/ )>C< (I)

^NH, \n/ ^0C,H,

H

/O.COOC.H, /OH

or C,h/ --* C,h/ (II)

^NH, \nHCOOC,H,

The well-known ease with which ^-aminophenols give ring
compounds suggested constitution (I). The possibility of
isolating and identifying a substance of such a constitution
seemed particularly important and worthy of close investiga-
tion for two reasons. In the first place, in the action of
amines on acid esters, and vice versa, of alcohols on acid
amides, an intermediate addition-product is quite generally
assumed to be formed according to

RCOOR+H,NR:r:RC(NHR)(OH)ORZ!:RCONHR+HOR,

but the addition-product has not been isolated. Formula ' ^'
represents such an addition-product of an amine to an estei,
made stable, possibly, by the general tendency towards the
formation of ortho rings. In the second place formula (I)
represents the constitution of the hydroxide base correspond-
ing to the hydrochloride of ethoxymethenylaminophenol (an
imido ether) if the salts of imido ethers are formed by the ad-
dition of the acid to the double bond between the carbon and
nitrogen atoms :'

C,H,< \C0C,H,+ HC1 — C,h/ >C<

\n^ \nh \ci

A substance of constitution (I) would have to show the most
intimate relationship to this hydrochloride ; and the exist-
ence or non-existence of such a relationship would go a great
way towards settling the constitution of the hydrochlorides of
imido ethers.

Constitution (II) would result from the migration of an
acyl group from a negative phenol radical to the basic amido

1 Vide Stieglitz : This Journal, ai, loi.

Molecular Rearrangement. 3

group. Similar migrations have been observed, occasionally,
before. Notably <?-nitroplienyl benzoate, closely related to
the nitro body under investigation, gives on reduction in hot
alcoholic solution benzoyl-o-aminophenol. Bottcher' showed
that the anhydro base, benzenylaminophenol, is formed by
loss of water in the experiment, and under the same condi-
tions goes over into benzoylaminophenol by the addition of
water :

NO,C,H,OCOC,H, -> N-C,H,0-CC,H, --*

II II

C,H,CONHC,H,OH.

He concluded, therefore, that benzenylaminophenol is an in-
termediate product in the rearrangement. But a substance of
formula (II) could result, without the formation of an anhy-
dro base, by further transformation of (I), according to

HO. /O

>C< >C,H, — C,H,OCONHC,H,OH,
C,H,0/ \NH

I change entirely analogous to the conversion of an acid ester
into an acid amide, as shown on page 10.

Such a rearrangement of an aminophenyl carbonate into an
oxyphenylurethane (II), demonstrated to occur only in the
ortho series, and to take place without the intermediate forma-
tion of an anhydro base, would prove the intermediate forma-
tion of compound (I), and thus incidentally strongly support
the modern conception of ester and amide transformations.
In such an event, also, the substance of constitution (I)
would be shown to have an existence, however, transitory,
and it might be possible to establish, even then, some con-
nection between it and the hydrochloride of ethoxymethenyl-
aminophenol, although the inability to isolate the hydroxide
itself would, no doubt, render such a work not only more diffi-
cult but also far less decisive in determining the constitution
of the hydrochlorides of the imido ethers.

With these objects in view, the present investigation was
suggested by, and carried out under the direction of. Professor
Stieglitz, to determine first, the true constitution of the reduc-

1 Ber. d. chem. Ges., i6, 630.

4 Ransom.

tion-product of (?-nitrophenylethyl carbonate (Bender's com-
pound) , that no opportunity might pass for isolating and in-
vestigating a possible hydroxide of constitution (I), and
secondly, to study more closel)'- than has been done by Bottcher
and others the mechanism of the rearrangement after reduc-
tion.

The facts bearing on the question of the constitution of
Bender's compound (m. p. 95°) known at the outs.:t of this
investigation were as follows : It crystallized out of strong
acid solution and could not possibly have the constitution
H,NC,H,OCOOC,H,, which he assigned to it. Such a sub-
stance would have approximately the basicity of aniline and
would dissolve readily in dilute hydrochloric acid (as has
since been confirmed by isolating aminophenylethyl car-
bonate).

On the other hand, Bender prepared an acetyl derivative of
his compound that on distilling gave acetylcarbonylamino-
phenol', CH3CO— N"— C„H,— O— C=0, which evidently is in

better accord with Bender's view of the constitution,
CH3C0NHC,HpC00C,H,, than, for instance, with the iso-
meric constitution, CH3COOC3H,NHCOOC,H,. Finally
Groenvik^ had already prepared an oxyphenylurethane (II),
HOC,H,NHCOOC,H, (soluble in alkalies, insoluble in dilute
acids), from ^-aminophenol and ethyl chlorformate, and found
its melting-point to be 85°, which is 10° lower than that of Ben-
der's compound. On comparing the two substances I found them
to be identical. After one or more recrystallizations, of prep-
arations made a number of times, the melting-point of both
bodies was found to be 86'',^ and this was not changed by
mixing the two compounds even without recrj^stallizing.
Both dissolve easily in alkalies and give in alkaline solution
the same beuzoate. In view of the solubility of the substance
in alkali no doubt can remain that Bender's compound was
not an aminophenylethyl carbonate but had suffered molecu-
lar rearrangement to (I) or (II).

1 Bender : Ber. d. chem. Ges., 19, 2270.

2 Bull. Soc. Chim., 25, 177.

3 The melting-point given by Bender is probably due to a typographical error or
to an unreliable thermometer : Vide, Ber. d. chem. Ges., 19, 2951.

Molecular Rearrange77ient. 5

On reducing o-nitrophenylethyl carbonate, (7-aminoplienyl-
ethyl carbonate is undoubtedly first formed. The acid solu-
tion remains clear for some time, and the precipitation of Ben-
der's compound is completed, in the cold, only after a day or
two. By keeping the solution very cold while reducing and
then rendering immediately alkaline,' and extracting with
ether, I was able to isolate a-aminophenylethyl carbonate — an
oil soluble in dilute acids but insoluble in alkali — as the
product of the first stage of the reaction. In the acid solu-
tion, therefore, a rearrangement of aminophenylethyl carbon-
ate to oxyphenylurethane must occur according to

H,NC,H,0(COOC,HJ — (COOC,H,)NHC,H,OH (II),

if Groenvik's oxyphenylurethane really has the constitution
one would be inclined to assign to it on the basis of its solu-
bility in alkalies and of its preparation from (7-aminophenol
and ethyl chlorforraate :

NH,C,H,OH + C1C0,C,H, — (CO,C,H,)NHC,H,OH.

It is obvious, however, that the attempt to prepare two com-
pounds,

/OCOOC^H, /OH

C,h/ and C,h/

\nh, \nhcooc,h,

could also lead to one and the same body, if in both cases the
well-known tendency of the ortho series to form ring com-
pounds was exhibited — both substances could yield the ring
compound,

/O /OH
c,h/ >C/ (I),

\nh ^oc,h,

as the stable form. It still remained, therefore, to determine
whether ^-oxyphenylurethane has the constitution (I) or (II).
The attempt to decide this question by alkylating with
methyl iodide in alkaline solution was quite unsuccessful.
Most of the substance was recovered unchanged. The sub-
stance also proved to be too sensitive to the oxidizing effects
of silver oxide to prepare a silver salt for the purpose of
methylation (blackening occurred under all conditions).

6 Ransom.

On the other hand, acyl derivatives were so easily made in
the cold, b}^ Baumann's method, with quantitative yields, that
this method of investigation was pursued next. It led to most
surprising results, the experimental data of which were care-
fully confirmed by me by two independent investigations with
an interval of half a year. By benzoylating oxyphenylureth-
ane, as Bender's and Groenvik's compound may be called,
a benzoyl derivative is obtained melting at 75°. 5. If oxy-
phenylurethane has the constitution its name expresses (II),
the benzoate should be C.H,COOC,H,NHCOdaH,. But

G c> 6 4 ti E>

exactly the same benzoyloxyphenyluretliane (m. p. 75°. 5) was
obtained by me on treating benzoyl-c?-aminophenol,

HOC,H,NHCOC,H„

(from ^-arainophenol and benzoyl chloride ; soluble in alka-
lies, insoluble in acids), in alkaline solution with ethyl chlor-
formate. Both bodies melt at 75°. 5 and there is no depression
of the melting-point on mixing them. The two reactions,

HOC,H,NHCOOC,H, -f CICOC.H,

and HOCeH,NHCOC,H, + CICOOC.H,,

give the same product. The inevitable conclusion (exclu-
ding molecular rearrangements) is that both acyl carbon atoms,

* **

C and C, must be attached to the nitrogen atom in benzoyl-

oxyphenylurethane. The latter would then be

/O. /OH /OH

C,H / >C< (I') or C,H / /CO,C,H, (IF). '

\N< X-)C,H, \N<

COC.H, ^^^^^^

The behavior of benzoyloxyphenylurethane towards heat
would seem to show that, when oxyphenylurethane is ben-
zoylated, the benzoyl group goes to the nitrogen atom. On
heating it gives alcohol and benzoylcarbonylaminophenol,' in
which the benzoyl group is found attached to nitrogen. The
same substance was obtained by benzoylating carbonylamino-
phenol :

1 Bender's acetaminophenylethyl carbonate shows similar behavior.

Molecular Rearrangement. 7

HNC.H.O— CO + CICOC.H, — >

J 1

C.H,CON.C,H,.0— C0+ HCl.

J 1

Benzoyloxyphenylurethane is insoluble in alkalies and
shows none of the properties of a phenol. An acyl group en-
tering the urethane molecule according to

HOC,H,NHCO,C,H, + CICOC.H, —

HOC,H,N(COC,H,)COAH,+ HCl,

would be without a parallel under the conditions observed.
Phenylurethane, ^-methoxyphenylurethane, etc., are not ben-
zoj^lated under the same conditions. Consequently formula
(II') can be considered as completely disposed of as a possi-
ble constitution for benzoyloxyphenylurethane. If both acyl

carbon atoms C and C are attached to nitrogen only formula
(I') would be left to represent the true constitution of ben-
zoyloxyphenylurethane, and oxyphenylurethane itself would
have the ring constitution

HNC.H.O— C(OH)OC,H, (I).

1 I

Imide groups in similar ring complexes have frequently
been found to give to compounds acid properties. For in-
stance, ethenyl-^-phenylenediamine,*

H.NCgH.N^C.CH,,

I 1

and ethoxymethenyl-^-phenylenediamine,''

H.NC,H,N=COC,H„

I 1

are soluble in alkalies, and this is undoubtedly due to the
presence of the imide group (NH) in these substances. The
solubility, in alkalies, of oxj^phenylurethane as a ring deriva-
tive could then very well be due to the imide group, and, on
benzoylating such a compound, the union of the benzoyl
group with the nitrogen atom, as found above, would be ex-
pected in a normal case. The behavior of oxyphenylureth-

1 Bamberger : Ann. Chetn. (I,iebig), 273, 274.

2 Sandmeyer : Ber. d. chem. Ges., 19, 2654.

8 Ransom.

ane towards acyl chlorides — exactly the same results were

obtained on using w-nitrobenzoyl chloride in place of benzoyl

chloride — agrees in every detail far better, therefore, with

constitution (I), HNC,H,OC(OH)OC,H„ than with consti-
I 1

tution (II), HOC,H,NHCO,C,H,.'

But in view of the fact that we were dealing with deriva-
tives, for which one molecular rearrangement of the mother
substance had already been positively proved, thef:^ conclu-
sions were further tested as follows : Benzoylox^'phenylureth-
ane, as (C,H,CO)N.C,H,OC(OH)OC,H,. being insoluble in

alkalies, the alcoholic hydroxyl group could have no marked
acid properties. Now oxyphenylmethylurethane can be pre-
pared from methylaminophenol and ethyl chlorformate ac-
cording to the equation :

CH3NHCeH,0H -f C1C0,C,H, —

C„H,0,CN(CH,)C,H,OH + HCl.

and being in every way analogous to oxyphenylurethane, it

must have an analogous constitution, and would be, as a ring

derivative, CH3NC,H,0C(0H)0C,H,. Such a compound, as
I I

explained in the case of benzoyloxyphenylurethane, having
no acid imide group, should have no marked acid properties.
On preparing oxyphenylmethylurethane it was found to dis-
solve quite readily in alkalies like an ordinarj^ phenol. This
result made the ring constitution for it, and consequently for
oxyphenylurethane itself, again very doubtful, since the sur-
prising nature of the acyl derivatives — verified experimentally
in every point again — could very well be due to molecular re-
arrangements (see below) analogous to the proved rearrange-
ment of aminophenylethyl carbonate. Recourse was had,
therefore, in the final instance to methylation of oxyphenyl-
urethane with diazomethane in neutral solution, following
Von Pechmann's method for determining delicate questionsof
constitution. Von Pechmann' has shown that substances of
an acid or a phenol character are easily methylated with this

1 See preliminary report, loc. cit., p. 1059.

2 Ber. d. chem. Ges., 28, S55.

Molecular Rearrangement. 9

reagent in absolute ether solution, thus minimizing the prob-
abilit}^ of molecular rearrangements, Oxyphenylurethane
gave with diazomethane, methoxyphenylurethane,

CH30CeH,NHC0,C,H„

recognized by converting it into methoxyphenylurea,

CH30C,H,NHC0NH,,

which was in everj' particular identical with a prepara-
tion made synthetically from ^-anisidine or from ^-anisidine-
urethane. The constitution of ^-oxyphenylurethane is con-
sequently

HOC,H,NHCOX,H, (II),
and not

NHC,H,OC(OH)OC,H, (I)' ■
I 1

as decided in the preliminary report. The reaction with
diazomethane is represented as follows :

HOC,H,NHCOAH, -j-CH.N,—

CH30C,H,NHC0,C,H, + N,.

The second object of this investigation, viz., the study of the
process of rearrangement of c-aminophen5'lethyl carbonate to
oxyphenylurethane, was also carried out to a considerable de-
gree. It was possible to isolate aminophenylethyl carbonate
as the first product of the reduction of (?-nitrophenylethyl car-
bonate in acid solution and as the first undoubted c?-amino-
phenol ester known. Its hydrochloride is quite stable in dry
condition ; in aqueous solution it gradually goes over into
oxyphenylurethane. But the free base, o-aminophenylethyl
carbonate, is voxy much less stable — standing over night in a
desiccator the oil is found to solidify to oxyphenylurethane —
losing its basic properties and acquiring acid characteristics.
This rearrangement of the free amine cannot possibly be due
to the intermediate formation of the anhydro base, ethoxy-
methenylaminophenol, and its subsequent saponification, ac-
cording to

1 Vide, preliminary report, Lxic. cit.

lo Ransom.

c,h/ — c,h/ >C0C,H, + H,0 -

OH

\NHCO,C,H,

since the anhydro base is quite a stable body, having been
preserved for months without excluding traces of moisture,
and even in contact with water no such rapid change was ob-
served as in the case of aminophenyl carbonate. This con-
clusion is confirmed by the fact that diacylaminophenols,
Ac.NHCgH.OAc', as shown below, apparently suffer similar
rearrangement, even more readily than aminophenylethyl car-
bonate itself, and, in their case, an anhydro base as interme-
diate product is plainly impossible. Aminophenylethyl car-
bonate, therefore, suffers rearrangement without the interme-
diate formation of an anhydro base, as Bottcher was led to
assume in the analogous case of the reduction of ^-nitro-
pheny] benzoate. Nevertheless, an intermediate ring deriva-
tive is most likely formed for the following reasons :

1. ^-Aminophenyl carbonate was found to be a perfectly
stable compound, not liable to rearrangement — the rearrange-
ment is peculiar to the ortho series.

2. The rearrangement occurs as long as the nitrogen atom
holds at least one hydrogen atom, and no longer.

Thus the fact that the two reactions,

HOC,H,NHCO,C,H, -f CICOC.H,,
and HOC,H,NHCOC,H, + C1C0,C,H,.

give one and the same substance, C,H,COOCeH,NHCO,CjH„
(see below) is most likely due to similar rearrangements of
the diacylaminophenols. But the analogous derivatives of
methylaminophenol give two series of isomers ; e.g.,

C,H,C00C,H,N(CH3)C0AH„
and (C,HAC)OC„H,N(CHJCOC.H„

both of which have been prepared, which are perfectly sta-
ble substances. There is, therefore, no direct exchange of
ac3*ls in the kind of rearrangement under discussion : its de-

Molecular Rearrangement. ii

pendence on the hydrogen of the imide group points clearly to
intermediate ring formations, which may be illustrated most
simply in the rearrangement of aminophenylethyl carbonate
itself :

/OCO,C,H, /O /OH

CeH,/ — C,h/ >C< (I) —

\NHH \NH ^0C,H,

/OH

c.h/

\nhco,c,h.

It is obvious that at least one, but only one, reactive hydro-
gen atom of the amine group is essential to such rearrange-
ments, and that the second one may be replaced by a second
acyl group without interfering with the possibility of such
ring transformations.

Thus, while oxyphenylurethane has not the ring constitu-
tion (I), there is every reason for believing that this ring
compound has a transitory existence when aminophenylethyl
carbonate goes over into oxyphenylurethane. No other
rational explanation of the change seems possible on the basis
of the experimental evidence presented. It follows then that
derivatives, RC(OH)NH(OR), of the ortho acids are formed,
but have no stable existence even under the favorable condi-
tions caused by a ring formation.

The unusual results obtained in preparing diacylamino-
phenols, to which frequent reference has been made, require a
few words of explanation. The same benzoyloxj^phenyl-
urethane (m. p. 75°. 5, always giving by saponification with
alkalies benzoic acid and oxyphenylurethane), was obtained
by the following three reactions :

a. The action of benzoyl chloride on oxyphenylurethane,

HOC„H,NHCO,C,H, + CICOC.H,.

b. The action of ethyl chlorformate on benzoylaminophenol
in alkaline solution,

HOC,H,NHCOC,H, -|- C1C0,C,H,.

c. The action of benzoyl chloride on aminophenylethyl car-
bonate in aqueous alkaline, or in ether, solution,

(COAHJOCeH.NH.-f CICOC.H,.

12 Ra7iso7n.

According to its behavior on saponification, and according
to preparation a benzoyloxyphenylurethane seems to have the
constitution C.H.COOCeH^NHCO.C.H, (A). According to
preparations b and <: and their behavior w^hen heated (p. 6) ben-
zoyloxyphenylurethane would be

(COOC.HJOCeH^NHCOCeH, (B). Since the

same body is produced only one of these formulae can be the
correct one. When an attempt is made to prepare -he second
compound it is evidently converted by rearrangement into the
stable modification. Formula (A) probably represents the true
constitution of the stable substance, for the reason that when
saponified it yields benzoic acid and oxyphenylurethane.
This method gave perfectly reliable results in determining the
position of the acyl groups in the case of bodies of undoubted
constitution in the methylaminophenol series,

AcN(CH3)C6H,OAc',

where both series of isomers have been prepared and found to
be stable. With these compounds, the acyl group attached
to oxygen is, without exception, removed first by saponifi-
cation with alkalies. When the compound (B) is formed by
methods b and c it at once goes over into the form (A) as fol-
lows :

(COAHJOCeH^NHCOCeH, — > CeH.COOCsH.NHCO.C.H,.

*
As the hydrogen atom H is essential for the rearrangement

(when it is replaced by methyl there is no rearrangement),
intermediate ring derivatives must be formed first similar to
that given on page 2 as representing the rearrangement of
aminophenylethyl carbonate. It is even possible that in the
case of the diacyl compounds such a ring derivative repre-
sents the final form of the stable modification ; for example,
benzoyloxyphenylurethane ma}^ be

C,H,C0NC6H,0C(0H)0C,H„
I 1

which would agree, in part, somewhat better with its behavior
than the constitution (A) assigned to it.

Molecular Rearrangement. 13

It is noteworthy that it has been possible to isolate the two
isomers, aminophenylethyl carbonate and ^-oxyphenylureth-
ane, and to observe the change of the former into the latter,
but that contrary to expectation all endeavors to isolate the
corresponding second isomeric benzoyl derivative (and the
second nitrobenzoyl isomer) have thus far been unsuccessful.
In fact the two isomers in the series of ^-diacylaminophenols,
AcOCeH.NHAc' and Ac'OCeH^NHAc, have in no instance
been obtained with absolute certainty as yet. In the case
of Ac being made benzoyl (CeH^CO), and Ac' w-nitrobenzoyl
(NOjCeH^CO) substances were obtained, crystallizing per-
sistently in different forms, but of practically the same melt-
ing-point, (152° and i53°)whichwas not depressed more than 4°
(softening slightly at 146°, melting at i49°-i53°) on mixing
the two substances. The one crystal form was twice observed
to changeover into the other and remain so permanently,' and
both compounds gave the same saponification products. It is
somewhat uncertain, therefore, whether the)^ really represent
chemical isomers of the two series just mentioned, but it is
probable that they do. Further investigation of the constitu-
tion of the stable compounds obtained will be carried out, and
further attempts made to isolate isomers in this series and ob-
serve the conditions of their change to the stable forms.

The work involved in attaining the first two objects of this in-
vestigation— determining the constitution of oxyphenylureth-
ane and studying the rearrangements in this group — left but
little time for taking up the third object, a study of the
connection between the ring derivative,

OC,H,NHC(OH)OC„H„

I I

and the hydrochloride of ethoxymethenylaminophenol,

OC,H,N = COC.H,
I 1

(see p. 2). As the ring derivative has only a transitory ex-
istence in the rearrangement of c»-aminophenylethyl carbonate
to t'-oxypheny lure thane (p. 11) the basis for an experimental
investigation seemed too slight for much work in this direc-

1 Vide, experimeutal part.

14 Ransom.

tion at present. It was shown that the above hydrochloride
gives, by hydrolysis, oxyphenylurethane under the same con-
ditions that aminophenylethyl carbonate does. The reactions
are exactly in accord with what was to be expected from
hydrolysis* of the hydrochloride of an imido ether formed by
the addition of hydrochloric acid to the double bond of
ethoxymethenylaminophenol \^

I. 0C,H,N=C0C,H,+ HC1 — 0C,H,NHCC1(OC,hJ.

I I I \

II. 0C«H,NHCC1(0C,H J + HOH —

i 1

OC,H,NHC(OH)OC,H, +HC1.

I 1

III. OC,H,NHC(OH)OC,H, — HOC,H,NHCOOC,H,.^

A more thorough investigation, for instance, of the reversi-
bility of reaction II is necessary, to make the reactions of per-
manent value for the theory of the constitution of imidoether
salts.

EXPERIMENTAL PART.

Reduction of o-Nitrophenylethyl Carbonate.

Oxyphenylurethane, HOC„H,NHCOOC,H,.— The reduction
was carried out at first in alcoholic solution, according to
Bender's directions : 27 grams of ^-nitrophenyl carbonate
were dissolved in alcohol, 65 cc. of concentrated hydrochloric
acid added, and then slowly 40 grams of powdered tin. The
whole was kept cool with ice-water. After three hours the
solution was filtered and about an equal quantity of water
added. Immediately an oil separated which slowly crystal-
lized on being placed in ice-water. The melting-point of the
crystals was 72°-83°. After crystallizing the substance three
times from water and then precipitating it from a solution in
benzene with ligroin, the melting-point remained constant at
86°. On heating the filtrate, from the oil which first separa-
ted, and then allowing it to cool slowly, more crystals sepa-

1 Stieglitz : This Journal, 21, 106.

2 Stieglitz ; Ibid., Loc. cit.

Molecular Rearrangement. 15

rated which had the melting-point 85°. If, however, the fil-
trate was allowed to stand without heating, crystals began to
separate only after some hours, and then continued to form
for some days. The melting-point was the same in both
cases.

A quicker method of carrying out the reduction is to use a
concentrated aqueous acid solution : 25 grams of the nitro
carbonate are put in a flask with 60 cc. of concentrated hydro-
chloric acid and very little water, then 40 grams of tin slowly
added, and the whole kept cold in ice-water during the first
part of the action, it being allowed finally to reach the ordi-
nary temperature. When the solution has become clear
(in about forty-five minutes) it is filtered through glass-wool,
after the addition of about an equal volume of water, and heated
nearly to boiling for a few minutes. An oil separates which, on
cooling, becomes a solid mass of crystals. On recrystallizing
twice from water the melting-point is 86". 5. If the solution,
during reduction, is allowed to become quite warm, mixtures
result which melt between 70° and 130'', consisting of oxy-
phenylurethane (m. p. 86°) and carbonylaminophenol (m. p.
137°). This was proved by separating the mixture, by frac-
tional precipitation, from a solution in benzene by carefully
adding ligroiu. Incidentally the presence of carbonylamino-
phenol was shown on treating a sample of oxyphenylureth-
ane, which happened to contain some carbonylaminophenol,
with diazomethane. Crystals separated in this case from the
methoxyphenylurethane, which is an oil, and these were iden-
tified as carbonylmethylaminophenol (m. p. 86°), by compari-
son with the synthetic compound.

The oxyphenylurethane, prepared as described, crystallizes
in rather short, thick needles or plates, varying somewhat
with the medium from which it is crystallized. It is soluble
in most of the organic solvents except ligroin, somewhat solu-
ble in cold water, much more so in boiling water. It is solu-
ble in cold, dilute, caustic alkalies, from which solution it is
precipitated unchanged by acids. The crude crystals (m. p.
72°-83°) deposited from the acid solution invariably dissolved
completely in dilute alkali. The change into oxyphenylureth-
ane was, therefore, not effected by the process of purification

i6 Ransom.

but occurred in the original acid solution. From a concentra-
ted solution in the alkalies the potassium and sodium salts
cr5'stallize in large needles.

Analyses of oxyphenylurethane, obtained by reduction of
i7-nitrophenylethyl carbonate, gave the following results :

I. 0.2485 gram substance gave 0.5410 gram CO^, ando.1371
gram H^O.

II. 0.3244 gram substance gave 21.5 cc. N at 15.75° ^^^
749.1 mm (corr.).'

Calculated for
CgHiiNOa. Found.

C 59-66 59.35

H 6.07 6.12

N 7.73 7-76

For comparison with Bender's product, oxyphenylurethane
was also prepared according to Groenvik's^ method, by treat-
ing (?-aminophenol (2 mols. ) in ethereal solution with e nyl
chlorformate (i mol.). Transparent, thick needles separated
out on partial evaporation, and these were recrystallized from
hot water. The melting-point was then 86. °5, and in appear-
ance the compound was similar to the substance obtained by
reduction of nitrophenylethyl carbonate. Mixtures of the two
had the same melting-point as either separately.

Befizoyloxyphenylurethatie, C,H,COOC,H,NHCO,C,H,.— In
order more fully to establish the identity of the two substances
as oxyphenylurethane, the benzoate was obtained from both
preparations. Each of the substances was dissolved in a
solution of potassium hydroxide (i mol.). In each case an
oil separated which, when shaken, hardened to a crystalline
mass. This was recrystallized twice from alcohol, to which a
little water had been added. The melting-point of each, as
well as that of a mixture of the two, was 75°. 5. Both were
insoluble in alkalies and acids, very soluble in warm alcohol
and most of the organic solvents. About 90 per cent of the
theoi'etical yield was obtained.

I. 0.1696 gram substance gave 7.9 cc. N at 19". 2 C. and
744.7 mm. (corr.).

1 Corrected for vapor-tension over 30 per cent caustic potash.
2 Bull. Soc. Chim., 25, 177.

Molecular Rearrangevient . 17

II. 0.3305 gram substance gave 15 cc. N at 23°. 5 C. and
735.3 mm (coiT.).

Calculated for Found.

C,eH,5N04. I. II.

N 4-91 5-35 5-o8

Benzoyloxyphen54urethane was also obtained by treating
benzoyl-^-aniinophenol with ethyl chlorformate.

Benzoyl-o-aminophenol, C,H,CONHC,H,OH. — This sub-
stance was first made by Hiibner,' but the following method
was found to give satisfactory results : i gram (2 mols.)
of (7-aminophenol was suspended in absolute ether, and
0.5 gram (i mol.) of benzoyl chloride then slowly added to
the mixture. A reaction began at once, the hydrochloride of
I molecule of the base being precipitated, mixed with some of
the benzoyl derivative which is not very soluble in ether.
The hydrochloride was dissolved out with water, the ether
soli;iion washed with dilute hydrochloric acid and water, and
the ether then evaporated. The benzoylaminophenol so pre-
pared melted at i65''-i67° (with decomposition), was soluble
in alkalies, and had all the properties of Hiibner's product.

Action of Ethyl Chlorformate on Benzoyl-o-aminophenol .

Three grams of benzoyl-^-aminophenol were dissolved in a
little more than i molecule of potassium hydroxide and 1.5
grams (i mol.) of ethyl chlorformate added. An oil separa-
ted out which solidified when shaken. The substance is very
soluble in alcohol and ether, fairly soluble in ligroin (40°-6o°) ,
from which it crystallizes in white needles. After three re-
crystallizations the melting-point was constant at 76°. 5.
• 0.2380 gram substance gave 0.5848 gram CO,, and 0.1143
gram H„0.

Calculated lor
Ci,H,6N04. Found.

C 67.36 67.01

H 5-26 5.33

As the melting-point was so near that of its supposed iso-
mer, obtained from oxyphenylurethane and benzoyl chloride
in alkaline solution, and as the appearance of the two was so
similar, more of that isomer was made and carefully purified

1 Ann. Chem. (Liebig), 2io, 3S7.

1 8 Ransom.

by recrystallizing it from ligroin. The melting-point now be-
came 76°. 5, and that of a mixture of the two was the same.
Neither substance decomposed at the melting-point, which
was unchanged after the substance solidified on cooling. The
substances obtained from benzoyl chloride and oxyphenyl-
urethane on the one hand, and from benzoylaminophenol and
ethyl chlorformate on the other hand, are therefore identical.
This unexpected conclusion was confirmed by a strdy of the
saponification products of the two substances.

One gram of benzoyloxyphenylurethane (prepared from
benzoylaminophenol) was shaken for an hour with a dilute
aqueous solution of caustic potash ( 2 mols. ) , warming slightly
toward the end. Nearly all went into solution. After acidi-
fying, the mixture was extracted with ether, the ethereal solu-
tion shaken out with bicarbonate of soda, dried, and the ether
evaporated. After recrystallizing from hot water the residue
melted at 83° ; mixed with ^-oxyphenylurethane the melting-
point was 84°, and it showed all the properties of this substance.
The bicarbonate solution was acidified and extracted with
ether, a substance being thus obtained whose odor and melt-
ing-point characterized it as benzoic acid.

Some of the benzoyloxyphenylurethane (p. 16) prepared from
oxyphenylurethane and benzoyl chloride was saponified ex-
actly as described above, and gave the same products — ben-
zoic acid and oxyphenylurethane, thus confirming the iden-
tity of the two substances. Consequently some rearrange-
ment in the molecule of one (or both) of them must have oc-
curred. According to the saponification-products the stable
substance is benzoyloxj^phenylurethane,

QH^COOC.H^NHCO.C.H,.

The attempt to prepare the two possible isomers was re-
peated, the solutions being kept below 5°, in the hope that, at
this temperature, real isomers might be isolated. The sub-
stances, however, were identical in every way with those de-
scribed above, as proved both by appearance and melting-point
as well as by saponification in alcoholic potash, which could be
accomplished in one or two minutes. As seen under a micro-
scope, no difference could be distinguished between the crys-

Molecular Rearrangement. 19

tal forms. Both appeared as small, well-formed prisms with
end faces perpendicular to the long axis. Finally, the two
substances were prepared at — 5°, at once washed with water,
acid, and alcohol, and then immediately saponified by means
of alcoholic potash. The same saponification-products were
obtained, showing that one of the isomers did not change into
the other stable modification in purifying it, but in preparing
it.

Dry Distillation of B en zoyloxypheny lure thane .

Several grams of the dry substance were heated in an An-
schiitz distilling flask until the thermometer in the vapor had
reached too° C. The liquid collected in the receiver was
then poured off and shown to be alcohol by the iodoform test.
The flask was then heated again under somewhat reduced
pressure, until crystals began to appear in the neck of the re-
ceiver. The liquid in the receiver was again poured off and,
by its odor and boiling-point (213°), proved to be benzoic
ether. A vacuum was again secured and most of the residue
distilled at 200°-220°. A solid distillate collected in the re-
ceiver. This was digested some time with caustic soda, and
filtered. The filtrate was acidified and extracted with ether.
On evaporating the ether a small amount of a ver}^ impure
substance was obtained, melting at 85°-io5°. It was proba-
bly impure carbonylaminophenol, but was not further investi-
gated. The larger part of the solid distillate was insoluble in
alkali and was washed with acidified water, then with pure
water, and finally recrystallized once from alcohol, in which
it is soluble with difliculty. Crystals were obtained melting
at 174° and possessing all the properties of benzoylcarbonyl-
aminophenol, which will be described presently. When water
was added to the mother-liquor from the first crj^stallization
from alcohol, crystals were deposited which were very soluble
in alcohol and melted at 97°-ioi°. Some of the substance,
sublimed i7i vacuo, melted at 102°. The crystals were long
needles soluble in cold ether and benzene, less soluble in
ligroin, somewhat soluble in boiling water, slightly in dilute
sulphuric acid, quite soluble also in concentrated hydrochloric
acid, reprecipitated by alkalies. It was suspected that this

20 Ra7isoin.

substance was benzenylaminophenol (m. p. ioi°-io3°), and
this was confirmed by preparing the latter synthetically ac-
cording to the method described b}^ Ladenburg.' The melt-
ing-point and properties of the substance were the same as
those described above, and a mixture of the two had the same
melting-point.

Benzoylcarbonyl-o-aminophenol, CeH^CoNCsH^OCO. — By

J J

distilling oxyphenylurethane, alcohol is given off and car-
bonylaminophenol is formed. As in distilling benzoyloxy-
phenylurethane alcohol was formed in large quantities, it was
concluded that the substance melting at 174° was the corre-
sponding benzoylcarbonylaminophenol. This substance is
not described in the literature, so that it became necessary to
prepare it synthetically. This was done by treating carbonyl-
aminophenol in alkaline solution with benzoyl chloride :

NHCcH.OCO + C.H^COCl— > C.H^CONCeH^OCO + HCl.
I 1 I \

Recrystallized from alcohol the substance melts at 174".

0.2851 gram substance gave 14.8 cc. of nitrogen at 18°, and
730.3 mm. (corr.).

Calculated for
C14H8NO3. Found.

N 5.85 5.88

B}^ mixing equal portions of this substance with that formed
by distillation (m. p. 174°) the melting-point was not lowered.
The two are identical. The products of the dry distillation of
benzoyloxyphenylurethane are therefore chiefly alcohol and
benzoylcarbonylaminophenol, to a small extent ethyl benzoate
and carbonylaminophenol, and finally some benzenylamino-
phenol. The formation of ethyl benzoate and carbonylamino-
phenol according to

C,H,COOC,H,NHCO,C,H, (I) —

HNC,H,OCO + CeH.CO.C^H,,

is perhaps in better accord with the constitution assigned to
benzoyloxyphenylurethane than with the other possible open-
chain form,

i Ber. d. chem. Ges., 9, 1526.

Molecular Rearrangeme7it. 21

(C,HAC)0C,H,NHC0C6H,(II) —

HNC.H^OCO + C,H,COOC,H..

I \

The formation of these compounds would involve the sepa-

*
ration of carbon atom C from nitrogen, which does not occur

as easily as from oxygen. But it is particularly worthy of

note that the main products of the dry distillation of benzoyl-

ox3'phenylurethane are decidedly in better accord with this

isomeric form' than with the one chosen on the basis of the

saponification-products.

C,H/ — CeHX >CO + C„H,OH,

^NHCOCeH. \N((

\COC,H,

appears as a very simple and likely reaction, but the forma-
tion of the same products from

CeH.CO.O.CsH.NHCO.aH,

evidently would involve a much more complicated reaction
since the benzo)'! group is finally found attached to nitrogen.
Much value was attached to this fact in my preliminary re-
port— rightly it seems as long as molecular rearrangements of
the diacyl compounds were not to be considered. But since
these must take place under much simpler conditions below
0°, their occurrence in the process of dry distillation would
not now be surprising. More work, however, has been
planned for the study of these conditions. It may be men-
tioned, in this connection, that the dry distillation of the
otherwise analogous w2-nitrobenzoyloxyphenylurethane does
not yield any ?/z-nitrobenzoylcarbonylaminophenol. In this
case the chief product is w-nitrobenzenylaminophenol, corre-
sponding to the decomposition-product obtained from benzojd-
oxyphenylurethane in smallest quantity — the anhj-dro base,
benzenylaminophenol. The formation of this substance ac-
quires special interest therefrom. It was suspected that it is
formed from benzojdcarbonylaminophenol as follows :

1 Or with the ring form, see preliminary report, loc. cit., p. 1063, and introduction,
p. 5.

22 Ratisoni.

C,h/ >C0 — CeH,/ \C-C,H, + CO„

VOCeH,

and it was shown that pure benzoylcarbonylaminophenol,
when distilled, does decompose to some extent in the manner
indicated. This may account for the fact that, in the case of
/»-nitrobenzoyloxyphenylurethane, as the w-nitrob^nzoylcar-
bonylaminophenol disappears from the distilled product, the
amount of anhydro base is proportionately increased. But it
has also awakened the suspicion that the first action of heat
may be to form alcohol and benzoyloxyphenyl isocyanate:'

C^H^COOCeH^NHCOOC.H, — C6H,C00C„H,N=C0.

This could very well be converted into benzoylcarbonyl-
aminophenol, or lose carbon dioxide, and givebenzenylamino-
phenol. The preparation of this isocyanate will, therefore, be
one of the first steps in the further study of these derivatives.

The result of the one case already given, in which the same
substance is formed in whatever order the two acyl groups are
introduced into the c-aminophenol molecule, was so unex-
pected that its correctness was tested by the use of other acyl
radicals, in order to determine whether it holds, in general, for
diacyl-c'-aminophenols. w-Nitrobenzoyl chloride being easily
available, it was first used in place of benzoyl chloride.

m- NUrobenzoyloxyphenylurethane ^
NO,C,H,COOC,H,NHCO,C,H„ was prepared from oxy-
phenylurethane and w-nitrobenzoyl chloride in alkaline solu-
tion. Recrystallized from alcohol it melts at 86°. 5.

I. 0.2425 gram substance gave 0.5147 gram CO^, and o. 1032
gram H,0.

II. 0.2541 gram substance gave 0.5388 gram CO^, and
0.0992 gram H^O.

III. 0.2698 gram substance gave 16.9 cc. N at 18°, and
730.4 mm. (corr.).

IV. 0.2523 gram substance gave 17.3 cc. N at 19"^, and
734.9 mm. (corr.).

V. 0.2085 gram substance gave 16.2 cc. N at 20°, and 728.8
mm. (corr.).

1 Vide Hof maan : Ber. d. chem. Ges., 14, 2727 ; Folin : This Journal, 19, 338.

Molecular Rearrangement. 23

Calculated for Found.

CibHi4N,0«. I. II. III. IV. V.

C 58.18 57-88 57-81

H 4.24 4.70 4.32

N 8.48 7.09 7.78 8.72

In the first two estimations of nitrogen, nitrite was found in
the potash solution. Therefore the last analysis was made in
a long furnace with the introduction of a spiral of reduced
copper 12 to 15 inches in length.

The substance is soluble in alcohol, ether, and benzene,
almost insoluble in ligroin, and insoluble in alkalies and
acids. By dissolving in benzene and then adding ligroin, very
fine prisms are formed.

Three grams of the substance (m. p. 86°. 5) were saponified
in the cold by alcoholic potash (2. mols.) and the products iso-
lated in the usual manner. They were found to be oxy-
phen^durethane and w-nitrobenzoic acid, having all the prop-
erties of the synthetic products. A very small amount of ethyl
w-nitrobenzoate (m. p. 4o''-42°) was also recovered. The
only products of the saponification of wz-nitrobenzoyloxy-
phenylurethane are, therefore, ?^i-nitrobenzoic acid and oxy-
phenylurethane. To a slight extent ethyl w-nitrobenzoate is
split from the molecule, exactly as occurs on heating the sub-
stance. No ?;e-nitrobenzoylaminophenol is formed.

Five grams of 7;z-nitrobenzoyloxyphenylurethane (m.- p.
86''. 5) were heated in a metal bath to 250°-26o°, an Anschiitz
flask being used. Alcohol was driven off, and also a small
amount of a solid melting at 8o°-i23°. The flask was then
exhausted and the contents distilled. Some decomposition
occurred, giving a slight odor of aniline. About 2.5-2.75
grams of distillate were obtained. This was ground in a mor-
tar with alkali, and filtered. On acidifying the filtrate a
small amount of a white solid separated, which proved to be a
mixture of 7«-nitrobenzoic acid and carbonylaminophenol.
The neutral residue (chief part) was then boiled out with
very little alcohol, to remove w-nitrobenzoic ether. On add-
ing water to the filtrate a solid separated, which melted at
38°-4i°, and proved to be this ether. The greater part was
found to be almost insoluble in alcohol, ether, and acetone ;

24 Ranso?7t.

fairly soluble in chloroform and acetic acid, depositing a white
solid melting at 203°-205°. Recrystallized from a large
amount of absolute alcohol, the melting-point was raised to
207°, resolidifying at 200°. The compound is also soluble in
concentrated hydrochloric acid, but is reprecipitated on add-
ing water. Reasoning from the results of the work on the
benzoyl derivative, it was thought to be either we-nitroben-
zoylaminophenol or w-nitrobenzenylaminophenol, and was
shown to be the latter by comparing it with synthetic prepa-
rations of these substances.

vi-Nitrobenzoylcarbonylaminophenol^
NOXfiH^CO—NC.H.OCO.— Molecular quantities of carbonyl-

aminophenol and ?w-nitrobenzoyl chloride in caustic soda
solution gave this substance. On recrystallizing from alco-
hol, in which it is very difficultly soluble, it becomes pure
white and melts at i99°.5-20i°.5, but resolidifies at 180°, again
melting at the same temperature as before. Mixed with the
substance of melting-point 207°, obtained in the dry distilla-
tion of m-nitrobenzoyloxyphenylurethane, the melting-point
was depressed to i75''-i93°, showing that the substances are
not identical. It is practically insoluble in ether, ligroin,
alkalies, and concentrated h5'drochloric acid, somewhat solu-
ble in acetic acid, easily in chloroform. The purity of the
substance was controlled by an analysis :

0.1986 gram substance gave 0.4289 gram CO^, and 0.0545
gram H^O.

Calculated for
C,4H8N205. Found.

c 59.15 58-89

H 2.81 3.04

ni'Nitrobenzenyl-o-ammophenol, C6H^(N02)C = NCeH^O. —

I I

This anhydro base was prepared by heating molecular quan-
tities of c-aminophenol and w-nitrobenzoyl chloride. The
residue was difl&cultly soluble in alcohol, but recrystallized
from this solvent in light grayish-yellow crystals of melting-
point 207°, resolidifying at 200°. Mixed with the substance
having the same melting-point, obtained by distilling wz-nitro-
benzoyloxyphenylurethane, no depression was observed. The

Molecular Rearrangement . 25

two substances are therefore identical. Mixed with ;;z-nitro-
benzoylcarbon5daminophenol (m. p. i99°-2oi°) the melting-
point was depressed 25°. The anhydro base is difficultly sol-
uble in most organic solvents, except chloroform, but is solu-
ble in concentrated hydrochloric acid, and is reprecipitated by
adding water.

0.1052 gram substance gave 0.2498 gram CO^, and 0.0346
gram H^O.

Calculated for
CisHgNjOj. Found.

C 65.00 64.76

H 3-33 3-6i

The high-melting product of the dry distillation of nitroben-
zoyloxyphenylurethane is, consequently, ;;z-nitrobenzenyl-^-
aminophenol. It is evident, therefore, that in distilling the
molecule lost both alcohol and carbon dioxide. Several at-
tempts were made to split off the first alone, by heating to
different temperatures, but without success — both coming off
at the same temperature, as was proved. The amount of the
high-melting substance was always much less than the theo-
retical. On that account a roughly quantitative experiment
was carried out as follows : 4.75 grams were slowly heated in
a metal bath to 125°. The loss in weight, 0.2 gram, was ap-
parently a little moisture. Pure, dry air was drawn through
the flask into lime-water, but no trace of carbon dioxide was
found ; nor had the melting-point of the substance changed.
Heating was continued until the first indication of decompo-
sition, 195", and the temperature kept between this and 200°
as long as action was visible. A very little oil had distilled,
and the presence of alcohol and carbon dioxide was proved.
The residue now weighed 4 grams. This was digested with cold
alcohol and filtered into a tared beaker. When the alcohol
had evaporated the residue weighed 2.63 grams. After boil-
ing out the more insoluble part with a very little alcohol it
weighed 0.8 gram, so that a large part was soluble in cold
alcohol. The part soluble in cold alcohol was digested with
caustic soda and filtered. On acidifying the filtrate a solid
was deposited, which, after recrystallization from alcohol and
water, was not quite pure, melting at i33°-i35°, and proved

26 Ransom.

to be carbonylaminophenol by the usual tests. The oily resi-
due, insoluble in alkali, solidified on standing, melted at 38°-
40°, and gave all the tests for 7;z-nitrobenzoic ether. The most
insoluble part, as well as that soluble in boiling alcohol, were
mixtures melting from i5o°-i8o°. No simple substance could
be separated by recrystallization, but on heating them to 250°
they were converted into w-nitrobenzenyl-o-aminophenol (m.
p. 207"). It is evident that in the drj- distillation of w-nitro-
benzoyloxyphenylurethane the decomposition into eth}^! nitro-
benzoate and carbonylaminophenol occurs to a larger degree
than in the case of benzoyloxj^phenylurethane (page 6).
The decomposition reactions, into nitrobenzoylcarbonylamino-
phenol, and of this into nitrobenzenylaminophenol, seem to
occur at the same temperature, so that the anhydro base be-
comes one of the main products. The theoretical bearing of
this has already been discussed (page 8).

As the substance by heat could not be made to lose alcohol
alone, a little was dissolved in concentrated sulphuric acid
and allowed to stand about five minutes. Then water was
added slowly, when a solid separated which was recrystallized
from much hot alcohol. The melting-point was i99°-2oi°,
and mixed with ;;z-nitrobenzoylcarbonylaminophenol, made
synthetically and melting at this point, no depression of the
melting-point was observed. We have here again the pecul-
iar fact that the 7;2-nitrobenzoyl group is found attached to
nitrogen, while the above synthesis and saponification of
w-nitrobenzoylurethane show it attached to oxygen, unless,
indeed the diacyl-^-aminophenols have a ring constitution,
which the monoacyl derivatives have been proved not to pos-
sess (page 9, introduction).

m-Nitrobe7i2oyl-o-ami?iophe7iol, {in)- O^NCsH^CONHCgH^OH.
— To 2 grams (2 mols.) of (7-aminophenol, suspended in ether,
an ether solution of 1.7 grams (i mol.) of w-nitrobenzoyl
chloride was added. The ethereal filtrate gave a small yield
of a substance melting at 207°. The solid which was precipi-
tated in the ether solution was washed with water to remove
the hydrochloride of aminophenol. Recrystallized from alco-
hol, the substance was obtained in short, thick prisms of a
light-yellow color, melting at 207°. Nitrobenzoylaminophe-

Molecular Rearrangement. 27

nol dissolves in alkalies, forming a bright-yellow solution, and
is reprecipitated unchanged on addition of dilute acids.

Action of Ethyl Chlorformate 07i ni-Nitrobenzoyl-o-aniinophenol.
— 3-35 grams of the nitrobenzoylaminophenol were dissolved
in a little more than the calculated amount (i mol.)
of potassium h^-droxide in solution, and 1.5 grams (i
mol.) of ethylchlorforraate added. On shaking a solid sepa-
rated in a somewhat oily condition. It was extracted with
ether, but this solution immediately commenced to deposit
crystals. The substance was purij&ed by dissolving in ben-
zene and carefully adding ligroin. The melting-point was
found to be 86°. 5. The 3'ield was quantitative.

0.1335 gram substance gave 0.2845 gram CO,, and 0.0536
gram H,0.

Calculated for
Cj6H]4N20g. Found.

C 58.18 58.12

H 4.24 4.42

The substance has the same appearance, crystalline form,
and melting-point as its supposed isomer, ?«-nitrobenzoyloxy-
phenylurethane, and the melting-point of a mixture of the two
is the same as that of either, proving the identity of the com-
pounds. This was fully confirmed by the result of saponify-
ing the substance whose preparation has just been described.

Two and three-tenths grams of the substance treated with
alcoholic potash, as described for 7«-nitrobenzoyloxypheuyl-
urethane, gave 0.93 gram w-nitrobenzoic acid (m. p. 139°-
141°) and 1. 18 grams oxyphenylurethane, which softened at
79° but melted at 84°. The melting-point was raised a little
by mixing with pure oxyphenylurethane. These are the
same saponification-products as ?;z-nitrobenzoyloxyphenyl-
urethane gives. Again the action of ethyl chlorformate on
nitrobenzoyl-c»-aminophenol,

HOC.H.NHCOC^H.NO, + C1C0,C,H„
and of nitrobenzoyl chloride on oxyphenylurethane,

HOCeH.NHCO.C.H, -f ClCOCeH.NO,,
give the same substance which, according to the saponifica-
tion-products, is ;;z-nitrobenzoyloxyphenylurethane,
N0,C„H,C00C6H,NHC0,C,H,.

28 Ransom.

A molecular rearrangement must then convert the isomer into
this same compound.

Diacyl-^-aminopheuols were also prepared, benzoyl and
nitrobenzoyl being used as the two acyl radicals, without
any carbethoxy group, particularly in order to determine
whether their abnormal behavior — originally in excellent
agreement with a ring formation, now considered to be due to
rearrangements by means of ring formations — is dependent in
any way on the reactivity of the carbethox}^ group. The pre-
liminary work indicated a difference of 15" in the melting-
points of the two substances, benzoylaminophenol w-nitroben-
zoate and ;?z-nitrobenzoylaminophenol benzoate. By further
purification, however, this difference was reduced to hardly
1°. The saponification-products of both substances were re-
peatedly found to be identical. However, the general ap-
pearance and crystalline forms remained persistently so differ-
ent that I was led to a careful and exact reinvestigation of
the reaction under different conditions. The results were the
same, so that I shall describe only those conditions which
seem to me to be the most favorable for the production and
identification of isomeric bodies.

ni-Nitrobenzoyl-o-aininophenol Be7izoate,
NO.CeH.CONHCeH^OCOCeH,.— 1.29 grams of ;;z-nitroben-
zoyl-^-aminophenol, freshly made and carefully purified, were
dissolved in a solution of sodium hydroxide (i mol.) at 0°,
and 0.7 gram (i mol.) of cold benzoyl chloride added, the
whole being well shaken. The separated solid was filtered,
washed with alkali, then thoroughly vv^ith water. A little
was dried, and without being crystallized it melted at 148°-
151°. The rest was washed with cold alcohol ; a little dis-
solved which had the melting-point I5i°-i53°. Some was re-
crystallized twice from alcohol ; it then melted at 153°.

0.2486 gram substance gave 17.4 cc. N at 22° C, and 726.9
mm. (corr.).

Calculated for
C,oHj4N205. Found.

N 7.73 7.78

The crystals were long, white, hair-like needles, not very
soluble in alcohol, insoluble in alkalies and acids. 3 grams

Molecular Rearrangement. 29

of the substance, without crystallization, were treated with
alcoholic potash in excess. In one minute all had dissolved,
and this was not precipitated on adding water. The solution
was acidified immediately, extracted with ether, the extracts
washed with water, and a solution of sodium bicarbonate (.5),
dried with calcium chloride, and the ether evaporated. This
residue {^A) containing the monoac3'laminophenols was dis-
solved in alkali and extracted with ether to remove any of the
original substance, and again acidified. A solid separated
which was recrystallized several times. The melting-point
was about 160°, though not sharp. A little was dissolved in
alkali and benzoyl chloride added. A solid formed, melting
at 178°, 2° above that given for dibenzoyl-^-aminophenol. To
remove any trace of w-nitrobenzoyl-(7-aminophenol, the mono-
acylaminophenol was dissolved in alcohol, ammonia added,
and hydrogen sulphide passed through the solution to reduce
the nitro body. After evaporation the solid residue was
washed with acid and water, then recrystallized from alcohol.
It now softened at 164°, melting at i65°-i67". Mixed with
benzoyl-<?-aminophenol this was not depressed, showing that
(.(4) consisted chiefly of this substance. The carbonate solu-
tion (j5) was acidified and extracted with ether, yielding a
substance melting at i39°-i4i'', and with all the properties of
?«-nitrobenzoic acid. The benzoate of wz-nitrobenzojdamino-
phenol gives, therefore, as the chief products of saponification
;«-nitrobenzoic acid and benzo3daminophenol, in which the
benzoyl group is attached to nitrogen, in the position origi-
nally held by the other acyl radical. Only traces of benzoic
acid and w-nitrobenzoylaminophenol are formed. The sub-
stance was saponified also in warm hydrochloric acid, a little
alcohol being used as solvent. The products were the same
as those in alkaline solution.

Benzoyl-o-aminophenol-rn-nitrobenzoate,
CeH^CONHC.H.OCOCeH^NO,.— 4 grams of benzoyl-^-amino-
phenol were dissolved in caustic soda, 3.5 grams (i raol.) of
?«-nitrobenzoyl chloride (in ether) added, and the whole
shaken for some time. The separated solid was w'ashed and
then recrystallized from alcohol. After the first recrystalliza-
tion the melting-point was constant at 152°. The crystals be-

3C Ransom.

ing colored, thej' were boiled with alcohol and bone-black,
filtered, then allowed to crystallize. If heated very slowly the
substance now melted at 151°. It was dried at 100" and ana-
lyzed.

0.1 178 gram substance gave 0.2862 gram CO,, and 0.0433
gram H,0.

Calculated for
CjoHjiN^Ob. Found.

C 66.29 66.21

H 3.86 4.07

The substance crystallizes persistently in short, thick
prisms, quite unlike the hair-like needles described above.

Two grams of the substance were shaken with a solution
containing 2 molecules of caustic potash, heat being applied
toward the end. Nearly all went into solution. After filtering
and acidifying, the solution was extracted with ether, the ether
solution washed with a solution of sodium bicarbonate {B) , and
the ether allowed to evaporate. The residue (^) containing
monoacylaminophenol was boiled with water, then dissolved
in alcohol, boiled with bone-black, and filtered. The crystals
were then digested with a very little cold ether. Nearly all
dissolved, leaving but a small amount of a substance melting
at 204°-207°, which was recognized as ?w-nitrobenzo34-o-amino-
phenol by the fact that a mixture of the two had the same
melting-point. The chief part of {A), soluble in ether, on
further purification softened at 158° and melted at 163°. It
is evidently benzoyl-<7-aminophenol mixed with a trace of the
nitro body, but this was not removed as in the former case.
The bicarbonate solution (^B) when acidified and extracted
with ether, left a substance melting at 136°-! 38° and having
somewhat the odor of benzoic acid. It has all the properties
of ;;2-nitrobenzoic acid (m. p. 141°). The chief saponification-
products of the w-nitrobenzoate of benzoylaminophenol are
therefore 7«-nitrobenzoic acid and benzoylaminophenol, the
same as those of the benzoate of ;/i-nitrobenzo3d-^-aminophe-
nol. But, exactly as in the case of the latter, very small
quantities of benzoic acid and nitrobenzoylaminophenol are
also formed — the latter containing the nitrobenzoyl group at-
tached to nitrogen where the benzoyl group was originally
held.

Molecular Rearrangement. 31

The melting-point of a mixture of benzoyl-^-aminophenol-
m-nitrobenzoate,

C,H,CONHC,H,OCOC,H,NO,
(m. p. 152°), and w-nitrobenzoyl-(7-aminophenol benzoate,

NOXeH.CONHC.H^OCOC.H,
(m. p. 153°), was less exact than that of either separately, as
it softened slightly at 146° and melted at 149°-: 53°. The
saponification-products are the same but the crystal forms are
persistently different. The solubility of the two forms, in
alcohol, are 31.16 per cent and 27.5 per cent, respectively.
Many attempts were made to change one form of crystals into
the other, but under no conditions could more than a trace of
the hair-like needles be changed into the prisms, and never
any in the opposite direction. The closeness of the melting-
points, the identity of the saponification-products,' and the
fact that by mixing the two substances the depression of the
melting-point is very slight, while, as a rule, in this series,
such a mixture causes a depression of i5°-20°, raise some
doubt as to the isomerism of the two substances. The per-
sistent difference in crystal form and the like difference in
solubility, make it very probable, on the other hand, that they
are isomers. In that event, however, rearrangement must oc-
cur either just before or just after saponification, unless the
substances are indeed ring derivatives.

One other attempt was made to obtain more sharply defined
isomers of the two diacyl-^-aminophenol series by means of
phenyl isocyanate. I^euckart has shown""' that phenyl iso-
cyanate, in the presence of aluminium chloride, unites with
"the amide group in <?-amidophenol, but that in substituted
(?-amidophenols the isocyanate reacts with the hydroxyl
group :

HOC.H^NH, + C,H,NCO — > HOCgH.NHCONHCcH, ;
HOC.H.NHCOR+CgH.NCO — CgH^NHCOOCgH.NHCOR.

Carbethoxyaminophenol Phenylcarbamate,
CeH^NHCOOQH^NHCO.C.H,, or

' C.H.NHCONHCeH^OCO.C.H,.—

1 See p. 36 as to the saponification-products of the two corresponding undoubt-
edly isomeric diacyl derivatives of methylaminophenol.

2 J. prakt. Chem., 41, 301.

32

Ransom.

Five grams of oxj^phenyluretliane and a little more than i
molecule of phenyl isoc3'anate were mixed in solution in abso-
lute ether, and a small amount of aluminium chloride slowly
added. The solution became warm and the odor of hydrogen
chloride was noticed. After standing some hours, and being
shaken at intervals, an oil settled out. On evaporating the
ether, and washing with water and hydrochloric acid, the oil
solidified. On dissolving in alcohol a small amount of carb-
anilide was separated. After recrystallizing several times the
melting-point was constant at ii6°-ii8°.

0.1215 gram substance gave 10.5 cc. N at 20°. 5 C. and
726.6 mm. (corr. ).

Calculated for
C,6H,6N204. Found.

N 9.33 9-65

The substance crystallizes in small, nearly white, prisms
and is fairly soluble in most of the usual solvents, but is in-
soluble in alkalies and acids.

Action of Ethyl Chlorformate on Oxydiphenylurea.

Chemically pure oxydiphenylurea' (m. p. 167") prepared
according to lycuckart, was dissolved in sodium hydroxide,
and ethyl chlorformate (i mol.) added. An oil separated
which was extracted with ether. The ether solution was
washed with alkali, water, acid, then again with water until
it gave no test for acid. The solution was dried for from fif-
teen to eighteen hours with fused sodium sulphate and the
ether evaporated. It was then put in a vacuum over sul-
phuric acid for three days. It did not crystallize, nor would
it crystallize on being cooled for a day to — io°-30° (cold win-
ter night). It is insoluble in acid and alkalies, easily soluble
in most of the organic solvents. As the oil could not be puri-
fied by distillation it was analyzed.

0.2867 gram substance gave 18.9 cc. N at 21° C. and 729
mm. (corr.).

Calculated for
CisHieNjO,. Found.

N 9-33 7-37

The oil was apparently quite impure, but it is evidently not

1 Leuckart gives the melting-point at i63°-i65°.

Molecular Rearrangement. 33

identical with the substance just described (m. p. Ii6°-ii8°),
as it could not be made to crystallize by inoculation with a
crystal of that substance. The small amount of the oil that
remained was saponified, after standing a couple of months,
with the result that, instead oxydiphenylurea, a few crystals
of oxyphenylurethane were obtained. This result is as diffi-
cult to explain, on the assumption of an unchanged open
chain, as those obtained with the other acyl derivatives, but,
as with these, it is easily understood by assuming a ring con-
stitution,

CeH,NHC0NC6H,0C(0H)0C,H„

J I

or a rearrangement of some of the substances before or after
saponification.

Acyl Derivatives of Methyl-o-aminophenol.

Of peculiar importance for the determination of the consti-
tution of oxyphenylurethane and the interpretation of the
nature of the diacyl derivatives of (?-aminophenol, has been
the study of the corresponding derivatives of (7-methylamino-
phenol, CHjNHCeH.OH. The replacement of one hydrogen
atom by methyl made it possible to determine the seat of
acidity in oxyphenylurethane and, preventing a rearrange-
ment of the diacyl compounds, made a close study of the two
isomeric series possible. The methylaminophenol necessary
for the experiments, I found, can be prepared much more
readily by means of carbonylmethylaminophenol than by way
of the corresponding thiocarbonylmethylaminophenol.'

Carbonylmethylaminophenol^' CHgNCeH^OCO. — This is best

i 1

prepared by dissolving carbonylaminophenol in methyl alco-
hol, in which is dissolved i molecule of potassium hydroxide,
and heating for two hours with somewhat more than i mole-
cule of methyl iodide. By this method 70 per cent of the
theoretical yield was obtained and the remainder of the car-
bony 1 body recovered. The best results were obtained by us-
ing not more than 5 grams of the carbonyl body for one ex-
periment. It can be purified by repeated crystallization from

1 Jour, prakt. Chem. [2], 42, 453.

2 See Bender : Ber. d. chem. Ges., 19, 2269 ; Carbonylethylaminophenol.

34 Ransom.

ligroin. It is very soluble in most organic solvents, but in-
soluble in acids and alkalies. It melts at 86°.

0.2347 gram substance gave 19.3 cc. N at 19° and 741 mm.
(corr.).

Calculated for

C8H7NO5. Fouud.

N 9.39 9.42

Preparation of o-Methylamhiophenol, CHjNHCgH^OH. —
Four to five grams of methylcarbonylaminoplienol are sealed
in a tube with 15-18 cc. of concentrated hydrochloric acid and
heated to 180° for one and a half hours. The contents of the
tube are then evaporated to dryness. By stopping the evapo-
ration just at the right point, crystals of the hydrochloride can
be obtained, but generally there remains a thick, sticky mass,
which gradually hardens. By neutralizing this with a solu-
tion of sodium carbonate the free base, methyl-(7-aminophenol,
is liberated, as a white solid, in a fairly pure condition, and
melts at 88°-90°.' The base turns brown on standing in
the air, especially when moist.

Benzoylmethyl-o-aminophenol, CeH^CO ( NCH^ ) CeH.OH .—
3.7 grams (2 mols.) of methyl-c'-aminophenol are suspended in
ether and 2.1 grams (i mol.) of benzoyl chloride added.
After shaking for some time, the ether solution is washed and
partly evaporated. Crystals are deposited, which, after two
recrystallizations from alcohol, melt at i6o°-i62°. The com-
pound was dried at 105° and analyzed.

0.2845 gram substance gave 15.9 cc. N at 17°. 5 C. and
727.5 mm. (corr.).

Calculated for
C,4H,3N02. Found.

N 6.16 6.31

The substance is soluble in alkali and is reprecipitated by
acids.

Benzoyhnethyl-o-aminophenylethyl Carbonate,
C6H,C0N(CH3)C6HPC0,C,H,. — 4.5 grams of benzoyl-
methyl-^-aminophenol were dissolved in i molecule of potas-
sium hydroxide, and then a little more than i molecule of ethyl
chlorformate added. A semisolid substance separated. This
was extracted with ether, and the ether solution washed and

1 Seidel gives m. p. 80°. See J. prakt. Chem. [2], 42, 453.

Molecular RearrangetJient . 35

dried. On evaporating the ether an oily, crj^stalline mass was
deposited, which was exceedingly soluble in alcohol, ether,
and benzene, fairly soluble in ligroin (40°-6o°). From the
last solvent long, silky needles, free from oil and melting at
68°, were obtained.

0.3419 gram substance gave 14.4 cc. N at 18°. 5 and 736.9
mm. (corr.).

Calculated for
CiiHjtNO,. Found.

N 4.68 4.80

One and nine-tenths grams of the substance (not quite c. p.)
were shaken one and a half hours with 2 molecules of caustic
soda. When nearly all had dissolved it was shaken with
ether, to remove any unchanged material, then acidified and
again extracted. The ether solution was washed with sodium
bicarbonate. On evaporating the ether and recrystallizing
the residue from alcohol it melted at i6o°-i62°, and was iden-
tical with benzoylmethyl-c'-aminophenol. The solution in bi-
carbonate contained a very small amount of a solid which was
not identified.

0- Oxyphenylmethylurethane ( ethyl-o- oxyphenylmethylcarbavi-
ate), HOC6H,N(CH3)CO,C,H,.— 2.72 grams (2 mols.) of
methyl-c-aminophenol were suspended in absolute ether ; to
this was added 1.28 grams (i mol. ) of ethyl chlorformate, and
then the mixture was shaken for some time. The ether solu-
tion was poured from the hydrochloride of the base, washed,
dried, and the ether evaporated. The resulting oil was dis-
tilled at reduced pressure (18-20 mm.), nearly all passing
over at 175^-180". The oil did not crystallize in a freezing-
mixture of ice and salt, nor on standing a week in vaaio in an
ice chest. Some months later, when the temperature was -20° to
— 30°, it was kept for twenty-four hours at this temperature after
adding a little ligroin, and thus it was crystallized. On re-
crystallization it tended to become oily, but I was able, by in-
oculation, to get a product sufficiently pure to determine the
melting-point as 53°. The oil is soluble in alkalies and is re-
precipitated by acids. It is separated from a little methylcar-
bonylaminophenol, formed in distilling, by dissolving in
alkali, extracting with ether, acidifying, and again extract-
ing. It was analyzed in the form of its benzoate.

36 Ransom.

Benzoyl-o-oxyphenylmethylurethane,
C6H,COOC6H,N(CH3)CO,C,H,.— The purified oil was dis-
solved in sodium hydroxide, i molecule of benzoyl chloride
added, and the whole shaken for some time. A solid separa-
ted, which was purified by recrystallization from alcohol. It
melted at 88°-90°.

0.2623 gram substance gave ] 1.2 cc. N at 18°. 5 C. and 725.6
mm. (corr.).

Calculated for
Ci,Hi7N04. Found.

N 4.68 4,79

The substance crystallizes in nearly white needles, is fairly
soluble in most organic solvents, but insoluble in alkalies and
acids.

The benzoate, saponified and treated as usual, gave ben-
zoic acid (m. p. 121°, not depressed by an admixture of the
acid) , and an oil which had all the properties of oxyphenyl-
methylurethane. The two reactions, between ethyl chlorfor-
mate and benzoylmethylaminophenol on the one hand, and
between benzoyl chloride and oxyphenylmethylurethane on
the other hand, led to two different substances — stable iso-
mers :

HOC6H,N(CH3)COCoH, + C1C0,C,H, —

(COah;)OC6H,n(ch,)coc6H, + hci,

and H0C,H,N(CH3)C0AH, + C1C0C6H, —

C6H,COOC6H,N(CH3)COAH, + HCI.

By saponification each conipou7id loses first the acyl bound to oxy-
gen. A mixture of the two isomers (melting respectively at
68° and 88"-9o°) had, of course, no constant melting-point,
but it melted partly at 58°, and from this slowly to 80°. The
former was much the more soluble in alcohol, and the general
appearance of the two was quite different.

7n-Nitrobenzoylniethyl-o-aminophenol,
HOC6H,N(CH3)COC6H,NO„ was prepared from methyl-(?-
arainophenol (2 mols.) and w-nitrobenzoyl chloride (i moL).
The substance is not very soluble in ether. On crystallizing
from alcohol beautiful, large, nearly white crystals separated.
They melted at 105°, and decomposed at iio°-ii5°. The sub-

Molecular Rcarrangemejit. 37

stance is soluble in alkalies. It was analj^zed in the form of
its benzoate.

?«-Nitrobenzo5'lmetli3d-^-aminophenol, HOC6H^N(CH3)-
COCeH^NO^ (1.5 grams), was dissolved in sodium hydroxide
and somewhat more than i molecule of benzoyl chloride
added. An oil separated, which solidified with difficulty. On
recrystallizing it from alcohol, the crystals were pure white
and exceptionally perfect, melting at 141°.

0.3231 gram substance gave 0.7908 gram CO.^, and 0.1227
gram H,0.

Calculated for
CviHigN^Oj. Found.

C 67.00 66.76

H 4.25 4.21

One gram of the substance was saponified exactly as in the
former cases. The acid part melted at ii7°-i20°, and, mixed
with benzoic acid, this melting-point was not depressed. It
also had the odor and other properties of benzoic acid. The
other portion, crystallized from ether, melted at 105° and de-
composed at 1 10°. It had all the properties of ?«-nitrobenzoyl-
methyl-<7-aminophenol.

771-Nitrobenzoate of Benzoylmethyl-o-aviinophenol,
NO,C,H,COOCoH,N(CH3)COC6H,.--Beuzoylmethyl-^-amino-
phenol, HOC6H^N(CH3)COC6H, (1.75 grams), was dissolved
in sodium hydroxide (i mol.) and w-nitrobenzoyl chloride (i
mol.) added. An oil separated which slowly solidified. On
recrystallizing it from alcohol, it separated in large, stout
crystals melting at 123°. 5.

0.2109 gram substance gave 14.5 cc. N at 2o°.5 C. and 735
mm.

Calculated for
CsiHjfiNjOs. Fouud.

N 7.45 7.78

The substance is quite soluble in alcohol, ether, and ben-
zene ; insoluble in acids and alkalies.

One gram of the substance was saponified, two to three
times the calculated amount of alcoholic potash being used.
All dissolved in a few minutes, and nothing was precipitated
on adding water. The solution was then acidified and treated
as in other cases, when it yielded benzoylmethyl-i?-aminophe-

38 Ransom.

nol, melting at i59''-i6i°, and w-nitrobenzoic acid, melting at
i39°-i4i°. A mixture of the two isomers, melting respectively
at 123°. 5 and 141°, melted at 115°. In the diacyl derivatives
of methylc-aminophenol, therefore, there is no molecular
rearrangement. Both isomers are stable, and by saponi-
fication the acyl attached to oxygen is always split off first.

Methylation of Oxyphenylurethane, HOCeH^NHCOOC.H,.—
The behavior of the diacyl derivatives of ^-aminor>henol, and
particularly of the acylated ^-oxyphenylurethanes, showed
plainly that we were dealing with derivatives of the ring form,

NHC6H,0C(0H)0C,H„

J 1

or with substances possessing a most remarkable tendency to
rearrangement. The study of the acyl derivatives of <?-methyl-
aminophenol, particularly of ^-oxyphenylmethj-lurethane, on
the other hand, made the ring constitution again improbable,
and the probability of molecular rearrangements correspond-
ingly greater. As no definite conclusion as to the constitu-
tion of oxyphenylurethane was reached by this line of experi-
ment, recourse was had again to the surer process of methyla-
tion. It had failed early in the course of this study, before
the investigation of the acyl derivatives had been taken up.
The failure of the earlier attempts at methylating oxyphenyl-
urethane seemed to be due to the fact that methyl iodide, in
boiling alkaline solution, reacted much too slowly to be of
value in the determination of such a delicate question of con-
stitution, and that no silver salt could be prepared on account
of the sensitiveness of the substance toward silver oxide. By
using Von Pechmann's method of methjdating by means of
diazomethane, perfectly definite results were obtained, oxy-
phenylurethane giving ^-methoxyphenylurethane (anisidine-
urethane), CH^OC.H^NHCOOC.H,, and having, therefore,
the constitution HOCeH^NHCOOC.H,.

Since it seemed possible that i7-anisidineurethane would be
obtained, it was thought best to prepare this substance first,
synthetically, from (?-anisidine to determine the best means of
identifying it. These derivatives of anisidine will be de-
scribed first.

Molecular Rearrangement. 39

o-Methoxyphenylur ethane {p-Anisidineurethane) ,
CH30C6H,NHC02C2H,.^Anisidine was suspended in water,
an excess of alkali added, and then one molecule of ethyl
chlorformate. An oil was formed, insoluble in acids. It was
washed with dilute acid, extracted with ether, and this solu-
tion dried. After evaporating the ether the oil was distilled
at 25-30 mm. pressure. This distillate was fractionated,
when a nearly colorless oil, boiling at i8o°-i82° under 26 mm.
pressure, was obtained.

0.3146 gram substance gave 20.4 cc. N at 18°. 5 C. and 733.1
mm. (corr.).

Calculated for
CjoHjaNOs. Found.

N 7.18 7.36

0-Methoxybromphenylethylurethane,
CH30C6H3BrNHCO,C,H,.— An attempt to brominate the
urethane, so as to get a solid derivative, showed that mix-
tures of two products were formed, one melting at 252°, the
other at 102°. 5, which it was very hard to purify. The last
sub.stance gave figures which corresponded very well with a
monobrom derivative of anisidineurethane, but the mixtures
were so difiicult of separation that it was not thought practical
to attempt an identification of anisidineurethane by this
method. The substance, melting at 102°. 5, was dried over
sulphuric acid in vacuo and analyzed.

I. 0.2302 gram substance gave 0.3796 gram C0„, and 0.0997
gram H,0.

II. 0.3181 gram substance gave 0.521 1 gram CO^, and
0.1298 gram H^O.

III. 0.1588 gram substance gave 0.2626 gram CO,, and
0.0652 gram H,0.

IV. 0.2740 gram substance gave 12.9 cc. N at 18°. 5 and
745.4 mm. (corr.).

Found.
I. II. III. IV.

44.96 44.67 45.08

4.82 4.52 4.53

5-43

A much more satisfactory identification was based on the
change of the urethane into the corresponding urea chloride

Calculated for
CioHijBrNOs.

c

H

N

43-79
4-37
5.10

40 Ransom.

by means of phosphorus pentachloride, according to the
method of I^engfeld and Stieglitz,' as modified \>y Folin and
Stieglitz. The urea chloride was converted into anisidine-
urea and anisidinephenylurea, which were easily purified and
identified. The reactions are represented thus :

I. CH,0C6H,NHC00C,H, + PC1, —

CH30C,H,NHC0C1 + aH.Cl -[- POCl, ;

II. CH,0C,H,NHC0C1 + 2NH3 —

CH30CgH,NHC0NH, + NH.Cl.

Two and two-tenths grams of anisidineurethane were placed
in a distilling flask, and after adding some chloroform
and 2.33 grams (i niol.) of phosphorus pentachloride the
mixture was warmed on a water-bath to 5o''-55° as long as a
gas (ethyl chloride) was evolved. Then the contents of the
flask were cooled and dry hydrogen chloride passed through
the solution until the chloroform and most of the phosphorus
oxy chloride were evaporated. More chloroform was added
and again evaporated. Without attempting to purify the
urea chloride it was converted into the urea by pouring it
into a concentrated solution of ammonia. Immediately an
amorphous solid, which was very soluble in alcohol, separated,
but on adding water to the alcoholic solution a crystalline
substance, which melted at i30°-i40°, separated. On boiling
it with ligroin, in which it was insoluble, then recrystallizing
it from water again, and finally from chloroform and ligroin,
the melting-point became constant at i43°-i45° (Beilstein
gives m. p. 146°. 5). It was identical with the urea made
from anisidine hydrochloride and potassium isocyanate.

0- Anisidinephenylurea, (CH30)CeH,NHCONHC6H,.— 0.61
gram of anisidine and 0.59 gram of phenyl isocyanate were
mixed in a small beaker, cooled with water. On stirring the
mass a thick, heavy oil formed. When the reaction was
ended dilute hydrochloric acid was added, which caused the
oil to solidify. The urea is soluble in alcohol, ether, and
chloroform, almost insoluble in ligroin (40°-6o°), Recrys-
tallized from alcohol, it melts at 144°. Dissolved in chloro-

1 This Journal, i6, 70.

Molecular Rearrangement . 41

form and precipitated with ligroin, it crystallized in thick
prisms with the same melting-point.

0.2709 gram substance gave 28 cc. N at 22° and 736.8 mm.
(corr.).

Calculated for
Cj4H,4N202. . Found.

N 11.66 11.65

On heating a little on platinum foil a strong odor of isocya-
nate was noticed.

The urea chloride of anisidine was again made, as before
described, from the urethane, and then poured into an excess
of pure aniline. A heavy, thick oil formed, mixed with a
solid. It was washed with dilute acid and water, the oil ex-
tracted with ether, and the ether evaporated. The thick oil
which remained refused to crystallize even when scratched
with a glass rod, and allowed to stand in vacuo for several
days. But on rubbing into the oil, moistened with alcohol, a
crystal of the synthetic urea, it became crystalline imme-
diately. It was recrystallized from alcohol, then from chloro-
form and ligroin. The crystals now softened at 141° and
melted at i42°-i44°. Mixed with the synthetic urea the point
of fusion was raised slightly. When heated on platinum foil
the isocyanate odor became distinctly perceptible.

Methylation of o-O xypheyiylurethane with Diazomethane. —
The diazomethane was prepared from nitrosomethylurethane
according to the method of Von Pechmann.' The methyl-
amine was prepared from acetamide^ according to Hofmann's
method. Nitrosomethylurethane was prepared by following
the description of Von Pechmann,^ the ethereal solution of the
urethane being placed in the separating-funnel in which it
was to be washed and dried. In this way I avoided entirely
the disagreeable effects experienced by this experimenter.

One and eight-tenths grams of oxyphenylurethane were

1 Ber. d. chem. Ges., 28, 855.

2 As no details could be found of the methods employed for making acetamide
from ammonia and acetic ether, experiments were carried out to determine the con-
ditions for obtaining: the best yield. By mixing :oo grams of the ether with 200 cc. of
concentrated ammonia (sp. gr. 0.90), and allowing the mixture to stand until it had
become homogeneous (two days), and then distilling, 75-Soper cent of the theoretical
amount was obtained.

3 Loc. cit.

42 Ransom.

dissolved in a small amount of ether, and to this solution was
added diazomethane dissolved in ether. The whole was then
warmed on the water-bath for an hour, a reflux condenser be-
ing used. The 3^ellow color of the solution nearly disap-
peared and a gas (nitrogen) was evolved. More diazometh-
ane was added audit was again warmed. When the color of
the solution remained light-yellow, which showed a slight ex-
cess of diazomethane, the ether solution was washed with
sodium hj'droxide, then with hydrochloric acid and water.
On drying and evaporating the ether an oil remained, insolu-
ble in acids and alkalies. It is somewhat viscous, possesses
a pleasant, ethereal odor, and is soluble in most of the organic
solvents. It could not be made to crystallize in the cold, but
was identified as <?-methoxyphenylethylurethane,

CH30C6H,NHCOAH„

by converting it into methoxyphenylurea and methoxycarb-
anilide by treatment with phosphorus pentachloride, fol-
lowed by ammonia or aniline, as described above for the syn-
thetic urethane. 0.7 gram of the urethane was thus con-
verted into the urea. A little oil separated, which soon
solidified. After filtering it off the solution was evaporated
to dryness. The solid residue was dissolved in chloroform,
and ligroin carefully added. Transparent crystals formed
which, after several recrystallizations, were of a light-brown
color, and melted at 145°, softening a little at i40°-i42°.
Mixed with the urea (m. p. i43°-i45°) made from anisidine
urethane, the melting-point was not depressed. The crystal
forms, as seen under the microscope, were the same, proving
conclusively that the two substances are identical.

More of the urea chloride of the methylated urethane was
made as already described, and poured into an excess of ani-
line. A thick oil was formed, which was washed with dilute
acids and water. On rubbing the oil with a crystal of the
synthetic urea it became a solid mass of crystals. These were
purified by recrystallizing from chloroform and ligroin. The
substance melted at 144°, and, mixed with the synthetic
phenylurea, the melting-point was not depressed. On heat-
ing some of the substance on platinum foil, the isocyanate

Molecular Rearrangement. 43

odor was easily perceptible. The methylated oxyphenyl-
urethane is undoubtedly an anisidine derivative, and there-
fore c?-oxyphenylurethane must contain a phenol hydroxyl
group.

0- Aminophenylethyl Carbonate, H^NCeH^OCOjC^H^. — Hav-
ing established the fact that a rearrangement occurs when
c'-nitrophenyl carbonate is reduced with tin and hydrochloric
acid, and that oxyphenylurethanewasthe only product thus far
liberated, it seemed of interest to isolate the free amino-
phenyl carbonate, which must be the first product of the re-
duction, as that might throw some light on the mechanism of
the rearrangement. After some unsuccessful attempts, the
following method was found to give satisfactory results :

Four grams of (7-nitrophenyl carbonate are put in a flask
with 15 cc. of concentrated hydrochloric acid and cooled in
ice-water. To this is added powdered tin in small portions
and the whole shaken, the temperature being kept near 0°.
If the solution is kept suflBcientlj^ cold, almost immediately
after becoming clear a fine, white, crystalline solid begins to
appear. This contains both organic and inorganic material
and is probably a double salt. When no more crystals form,
the contents of the flask are poured slowly into a well-cooled
solution of 50 grams of potassium hydroxide in 50 cc. of water.
If too much heat is allowed to develop at this stage the re-
sults are negative. The alkaline solution is immediately ex-
tracted six times with ether, a sufficient amount of water be-
ing added during the last extractions to dissolve the potas-
sium chloride. The ether solution is washed with water and
then dried with solid potassium hydroxide. When dry, the
ether is poured off and dry hydrogen chloride passed into it.
A copious, white precipitate of the hydrochloride of c'-amino-
phenylethyl carbonate is formed which can be filtered and
dried on a clay plate. It is stable at the ordinary tempera-
ture, and remains perfectly white. From 60-70 per cent of
the theoretical yield is obtained. It melts at i50°-i52° with
evolution of much gas. It is very soluble in cold water and
in alcohol. Sodium carbonate decomposes it, forming amino-
phenylethyl carbonate, an oil which is soluble in dilute acids.
On heating an aqueous solution of the salt it becomes cloudy

44 Ransojti.

before the boiling-point is reached, and an oil separates which
gradually solidifies on cooling. On recrN'stallizing this solid
from somewhat diluted alcohol, crystals are formed which
melt at 85°-86°.5, and resemble oxyphenylurethane. When
these crystals are mixed with oxyphenylurethane the melting-
point is not depressed. It is also soluble in alkalies and is
reprecipitated by acids. A nearly saturated solution of the
hydrochloride of <?-aminophenylethyl carbonate was made, and
to this a concentrated solution of platinic chloride was added.
After a few minutes, yellow crystals formed. They were
somewhat soluble in water and alcohol, insoluble in ether.
They were washed with ether in which was some alcohol,
dried and analyzed.

0.0446 gram chlorplatinate gave 0.01125 gram of platinum.

Calculated for
Ci8H24N.20„PtClg. Found.

Pt 25.16 25.22

0.1664 gram of the hydrochloride was titrated with tenth-
normal silver nitrate, potassium chromate being used as indi-
cator. 7.7 cc. of the solution were required.

Calculated for
CsHi-jNClOs. Found.

CI 16.32 16.42

Some of the salt was put into a separating-funnel with
ether and a solution of sodium carbonate added to alkaline re-
action. The ether solution was then washed, dried with
fused potassium sulphate, and the ether evaporated in vacuo.
Aminophenylethyl carbonate remained as a basic oil, which
was easily soluble in dilute acids and could be converted back
into the hydrochloride and the chlorplatinate of (?-araino-
phen5'lethyl carbonate. It was kept over sulphuric acid.
After twelve hours it had changed to a cr3'stalline solid which
melted at 86°, and it was now soluble in alkalies and was re-
precipitated by acids. All the properties of this solid, as well
as the melting-point of a mixture with oxyphenylurethane,
proved it to be this substance.

In an attempt to convert the hydrochloride of aminophenyl-
ethyl carbonate into the corresponding urea, 0.3 gram of the
hydrochloride was dissolved in water and a solution of potas-

Moleadar Rearrangement. 45

siutn isocyanate added. An oil separated which was dis-
solved in water, and, on standing some hours, crystals melt-
ing at 86° separated, which proved to be oxyphenylurethane.
Another attempt was made, an alcoholic solution of the salt
being used, but it was converted into the urethane,
as in the former experiment. Evidently the rearrangement
takes place rather than the usual addition to isocyanic acid.

One gram of the hydrochloride was treated with an ice-cold
solution of 2 molecules of sodium h\^droxide and a little more
than I molecule of benzoyl chloride added. The solution
was then extracted with ether several times. The residue,
left on evaporating the ether, was again digested with very
little ether, which dissolved all but a little, and this, recrys-
tallized from alcohol, melted at 180°, and, mixed with diben-
zoylarainophenol, did not melt lower. ^ The ether solu-
tion deposited crystals which, after one recrystallization from
ligroin, melted at 76° and in its crystal form as in its other
properties, was identical with the benzoyl derivative of 0x5^-
phenylurethane. A mixture of the two had the same melt-
ing-point.

In a second attempt to prepare the isomer of the latter com-
pound a little more than i gram of the hydrochloride, corre-
sponding to 0.9 gram (2 mols.) of the free base, was put in a
separating-funnel with ether and then treated with an excess
of sodium carbonate. The ether solution of the free base was
washed, dried with solid potassium hydroxide, and then i
molecule of benzoyl chloride added. After a minute the
hydrochloride of i molecule of the base separated. This was
filtered out, the ether washed with alkali, then with dilute
acid, finally with water, and dried with calcium chloride. On
distilling the ether a solid remained which melted at 76°.
Mixed with the benzoyl derivative of oxyphenylurethane, the
melting-point was not depressed.

In order to compare the behavior of aminophenylethyl car-
bonate towards dilute acid, with that of ethoxymethenyl-
aminophenol,

0-C,H,N=C-OC,H„

I I

1 Hiibuer gives 176° as the melting-point of this derivative.

46 Ransom.

I gram of the hydrochloride was allowed to stand twenty-four
hours with less dilute hydrochloric acid than was sufficient to
dissolve all of it. Then it was completely dissolved in this
reagent. After standing some days longer, the solution was
divided into two portions and one was extracted with ether.
On evaporating the ether a solid remained, which, after one
recrystallization from water, melted at 70°-! 19°. The other
portion, on standing longer, deposited crystals which melted at
70°-8o°, but when mixed with oxyphenylurethane, the melting-
point was raised a little. Decomposing this by distilling some of
it into the upper part of a test-tube the melting-point was raised
to i35°-i37°, which proved the sublimate to be carbonylamino-
phenol. It is quite certain that the original product is a mix-
ture of oxyphenylurethane and carbonylaminophenol, as I
have found that mixtures of these, in different proportions,
have melting-points anywhere between 70° and 120°. By
distillation they give pure carbonylaminophenol.

Action of Hydrochloric Acid on Ethoxymethenylo-aminophenol.
— In the reduction of the c-nitrophenyl carbonate it was
thought possible that the h3-drochloride of the anhydro base,
ethoxymethenylaminophenol, might be formed' instead of the
amino base. A comparison of this base with aminophenyl-
ethyl carbonate was, therefore, undertaken. Some of the
anhydro base, obtained through the kindness of Dr. H. N.
McCoy, was dissolved in absolute ether and dry hydrogen
chloride passed into the solution. The first bubbles produced
a crystalline deposit, but this immediately disappeared, and,
on evaporating the ether, only carbonylaminophenol remained.
The experiment was repeated in dry ligroin solution at — 11°.
A solid separated which was stable at that temperature, but
when put on a clay plate in a cold room the crystals began to
decompose, giving off a gas (ethyl chloride) which burned
with a green flame. On the clay plate there remained pure
carbonylaminophenol (m. p. ise^-isS").^ The behavior of this

1 As in Bottcher's experiments with o-nitrophenylbenzoate.

2 This is the typical behavior of the hydrochloride of an imido ether which
ethoxymethenylaminophenol hydrochloride represents :

/O /Cl /O

/ >C< ^ C,H4< >CO + ClC,H6.

Attention maybe called to the unusually low temperature at which the salt decom-

Molecular Rearrangement . 47

base is therefore different from that of the amino base formed
by reducing (7-nitrophenyl carbonate. And this fact, coupled
with the observation already given, that the amino base on
standing is converted into the urethane while the anhydro
base is stable in ordinary moist air, proves conclusively that
the latter is not an intermediate product in the intramolecular
rearrangement.

For reasons stated in the introduction (p. 9), it was
thought desirable to compare the behavior of the anhydro
base toward dilute hydrochloric acid with that of amino-
phenylethyl carbonate (see above). The anhydro base was
allowed to stand several days in contact with dilute hydro-
chloric acid. The oil gradually disappeared and was replaced
by white crystals. When all the oil had disappeared the
crystals were filtered off, recrystallized from water, and dried.
They melted at 70°-8o°, were soluble in alkali, and reprecipi-
tated by acids. On distilling into the upper part of a test-
tube and then recrystallizing from water, in which was a little
alcohol, a substance melting at i36°-i38° was obtained, which
proved to be carbonylaminophenol. The low-melting sub-
stance is certainly a mixture of oxyphenylurethane, and car-
bonylaminophenol. The products formed are identical with
those obtained by allowing the hydrochloride of aminophenyl
carbonate to stand in an acid solution.

p-Nitrophenyl Carbonate, NO.CgH^OCOOC.H,.— The pe-
culiar rearrangement observed on reducing <?-nitrophenyl
carbonate in the usual way, by which ^-oxyphenj'lurethane
results, suggests a comparison of corresponding derivatives
in the meta or para series, preferably the para series, as that
is the more susceptible to molecular rearrangement, and
usually resembles the ortho series more than the meta series
does.

Ten grams of ^-nitrophenol were treated with excess of
potassium hydroxide, and somewhat more than i molecule of

poses. It recaUs the behavior of the hydrochloride of ethylphenylimidochlorfor-
mate, ClC(NC6H(i)OC2H5, which, decomposing below — 15° into ethyl chloride and
chlorformanilide, could not be isolated by Lengfeld and Stieglitz.i although its
formation was clearly indicated and formed an important link in their arguments.
The properties of the solid hydrochloride of ethoxymethenylaminophenol fully sup-
port their assumption of such an intermediate hydrochloride.
1 This Journal, 16, 73.

48 Ransom.

ethyl chlorformate was added in small portions, wliile the con-
tents were vigorously shaken. A quantitative 5deld of a
nearly white solid melting at 68° was obtained.

0.2533 gram substance gave 14.8 cc. N at 17° and 736.8 mm.

Calculated for

C9H9NOB. Found.

N 6.63 6.71

The carbonate is soluble in ligroin, ether, alcohol, and
somewhat in boiling water, from all of which it crystallizes in
long, white needles.

Synthesis of p-Nitrophenylethyl Carbonate .

In order fully to establish that in /-nitrophenyl carbonate
the carbethoxy group is attached to phenol oxygen and not
to the nitro group, a synthesis from phenylethyl carbonate
was carried out. The phenjd carbonate was cooled to 0° in
ice-water and then poured slowly into ice-cold, fuming nitric
acid. On pouring the mixture into water a nearly white,
crystalline solid separated immediately. If allowed to stand
for some time in the strong nitric acid the product is much
more impure. On recrystallizing from alcohol it crystallizes
well and melts at 68°. A mixture of this with the carbonate
made from /)-nitrophenol has the same melting-point as either,
and the two are identical in all their properties.

p- Aminopheny let hy I Carbonate, H^NCgH^OCO^CjII,. — Several
attempts were made to reduce the carbonate with tin and
hydrochloric acid, in aqueous and in alcoholic solution, but
the 5'ields in each case were small owing to the fact, after-
wards discovered, that the base is somewhat soluble in water
and is not extracted with ether completely. The best results
are secured by proceeding as follows :

Two grams of the nitrocarbonate were dissolved in warm
alcohol, concentrated hydrochloric acid added, and then
slowly, and in small portions, 11 grams (6 mols. ) of stannous
chloride. The solution became light-yellow. After fifteen
minutes a drop gave no precipitate with water. The whole
was then diluted and hydrogen sulphide passed into the .'solu-
tion, until all the tin was thrown down. After filtering, the
solution was concentrated m vacuo at 5o°-55°. On standing,

Molecular Rearrangement. 49

white crystals of the hydrochloride of /•-aminophenylethyl
carbonate were deposited. The yield was 70 per cent. The
crystals are very soluble in water. From dilute solutions
caustic alkalies do not precipitate the base. From fairly con-
centrated solutions sodium hydroxide or sodium carbonate
precipitates an oil which solidifies on standing and then melts
at 36°. On recrystallizing it an oil, which solidifies only on
standing some days, is formed at first. Both crystals and oil
dissolve in acid. The base is somewhat soluble in water,
gives no purple color with ferric chloride, and does not be-
come colored in the air. On heating the hydrochloride it
darkens at 160° and melts at 197° with violent decomposition.
0.2005 gram of the hydrochloride dissolved in water and
titrated with tenth-normal silver nitrate, potassium chromate
being used as indicator, required 9.3 cc. of the nitrate solu-
tion.

Calculated for
CjHijNOaCl. Found.

CI 16.32 16.46

The platinum salt was made in aqueous solution by pre-
cipitating with chlorplatinic acid, washing the precipitate
with alcohol and ether, and then drying in vacuo over sul-
phuric acid.

0.2869 gram substance gave 0.0722 gram Pt.

Calculated for
(CgHi2N03)2PtCl8. Found.

Pt 25.16 25.16

It is a bright-yellow, crystalline solid melting at 237°,
blackening at 208°.

p-Ureidophenylethy I Carbonate, NH,CONHC«H,OCOOC,H,.
— The paraminophenylethyl carbonate can also be identified
easily by converting it into its urea. 0.3 gram of the hydro-
chloride was dissolved in a little water and the calculated
amount of potassium cyanate added. An oil separated which
soon became crystalline. On crystallizing once from hot
water it was nearly white and melted at 147°- 150°. It is in-
soluble in alkalies.

All attempts to cause a rearrangement of />-aminophenyl-
ethyl carbonate to /-oxyphenylurethane were unsuccessful.
One gram of the hydrochloride was dissolved in water, and.

50 Ransom.

after the addition of some hydrochloric acid, the solution was
allowed to stand two days. No change having taken place,
apparently, the solution was boiled two and a half hours un-
der a reflex condenser. It was then allowed to stand a week.
The solution was then evaporated at 5o°-6o° hi vacuo in an
atmosphere of hydrogen sulphide. The residue was washed
with a little water, filtered, and tested as follows :

Ferric chloride produced a deep-purple color, due to
/-aminophenol. Sodium carbonate produced a solid which
gradually turned brown on standing. A urea, made as in the
former experiment, melted at 167°, blackening at 162° (/-oxy-
phenylurea melts at 167°). It was quite soluble in alkalies.
Mixed with the urea of />-aminophenyl carbonate (m. p. 147°-
150"), the melting-point became i3o°-i50°. Evidently the
acid had caused a saponification of the hydrochloride of
/-aminophenylethyl carbonate to that of />-aminophenol.

Another gram of the hydrochloride of ^-aminophenylethyl
carbonate was dissolved in water and allowed to stand at the
temperature of the room for a week. The solution was then
evaporated as was the first portion. Ferric chloride gave a
very light-purple color. Sodium carbonate precipitated an
oil which became solid on inoculating it with a crystal of
/-aminophenyl carbonate. The oil dissolved in hydrochloric
acid. The urea was made as in the former case. It softened
slightly at 142°, melting at i46°-i48°. Mixed with a syn-
thetic /-ureidophenylethyl carbonate, the melting-point was
not lowered. It was insoluble in alkalies. No change had
occurred. A third portion of the h^'drochloride was dissolved
in water and alcohol, allowed to stand a week, and then
treated as in the former case.

Ferric chloride gave a reddish-purple color. Sodium car-
bonate separated an oil which gave tests corresponding to
/-aminophenyl carbonate and formed the same urea. It is
evident from these tests that />-aminophenylethyl carbonate ex-
hibits no tendency to change into a urethane correspond-
ing to />-oxyphenylurethane.

I wish here to express my thanks to Professor Stieglitz for
valuable suggestions and for the careful attention he has
given to each step of this work.

DIAZOCAFFEINE.

By M. Gomberg.

Such few of the aliphatic amines as yield diazo derivatives
at all have the amido group linked to a primary or secondary
carbon atom. As a consequence the tendency towards the
formation of a closed ring is easily satisfied. Curtius' histori-
cal diazoacetic ester' has the constitution

CH,.C00aH, — CH— COOC^H,.

I /\

N:=N— X N=N

A similar constitution is ascribed to the esters of diazo-
propionic^ and diazosuccinic'^ acids, diazoacetonitril,*

CN.CH<^ II , as well as to the diazomethane itself, CHY II •

There is, therefore, a wide difference between these diazo
compounds and those of the aromatic series. The first can-
not combine with phenols and amines to form azo dyes, while
the latter alwaj'S do so. No diazo derivatives have been pre-
pared of aliphatic amines in which the amido group is
linked to a tertiarj' carbon atom whose three valencies are
taken up by three radicals. Some heterocyclic amines, how-
ever, with a tertiary carbon atom, have been diazotized, and
the derivatives so obtained closely resemble those of the purely
aromatic series in their capacity for coupling with phenols and
amines. In all such heterocyclic amines the carbon atom
carrying the amido group has a linking similar to that in the
aromatic amines :

C N N N

^ ^ \ \

C— NH„, C— NH„, C— NH., C— NH,.

I " I ' II " II

C C C N

Aromatic. Heterocyclic.

1 Curtius ; J. prakt. Chem. [2], 38, 396.

2 Curtius and Koch : /bid., 4S7.

3 Curtius and Koch : Ibid., 474.

* Curtius : Ber. d. chem. Ges., 31, 2489.
6 Von Pechmann : Ibid., 27, 1888.

52 Gomberg.

Not all heterocyclic amines of the above constitution can,
however, be diazotized. Only very few have yielded such
derivatives, and in some cases the diazo salts were not
isolated in the dry state, but could exist only in solution.
Amidotetrazol,' diamidophenylosotriazol,'' amidotriazol,* as
well as its methjd and carboxy derivatives, are the most im-
portant examples of heterocylic amines that have been suc-
cessfully diazotized.

Caffeine, although usually looked upon as an aliphatic
compound, behaves in many of its reactions more like an aro-
matic body. Its halogen substitution derivatives part with
the halogen with great difficulty ; ammonia acts upon them
only at a comparatively high temperature and pressure, while
zinc ethyl'' does not act at all at a temperature of i20°-i3o° C.
Caffeine, like all other ureides, can be looked upon as a
heterocyclic compound. Its constitution from this standpoint
is that of a naphthalene-like combination of a methylated
pyrimidiue and glyoxaline rings :

CH, CH3

CH N CO N

CH

N
CH,

Recent formula.*

It is therefore not strange that amidocaffeine, with the
amido group linked to the tertiary carbon atom, should give a
diazo compound on treatment with nitrous acid, even if the
amine itself is a very weak base.

Diazocaffeine is a very unstable substance, and so far has
been obtained only in solution ; even in that form it could be

1 Thiele and Marais : Ann. Chem. (Liebig), 373, 144 ; 387, 244.

2 Thiele and Schleusner : Ibid., 395, 150.

^ Thiele and Manchot : Ibid., 303, 40, 50, 54.

4 Gomberg : This Journal, 14, 616.

5 I5. Fischer : Ber. d. chem. Ges., 30, 553.

Diazocaffeine . 53

kept without decomposition at a comparatively low tempera-
ture only. It possesses a very great tendency to combine
with aromatic phenols and amines. The beautiful azo dyes
so formed are quite stable, and are of intense dyeing power.
The following few typical examples are described in this
paper : Caffeineazophenol, caffeineazodimethylaniline, caf-
feineazophenylenediamine, and caffeineazo-/5-naphthol.

That the caffeine molecule is not broken up by the action
of nitrous acid, but that a true diazo salt of caffeine is
formed, has been proved in two ways. First, if caffeine in-
stead of its amido derivative is subjected to the same treat-
ment with nitrous acid, it remains entirely unchanged.
Second, the azo dyes (the dimethylaniline compound, for in-
stance) on treatment with stannous chloride, furnish almost
quantitatively amidocaffeine and the corresponding aromatic
body :

C.H,NA-N : N.C,H,N(CH,), + 4H =

C,H,NA.NH, +H,N.C6H,.N(CH,),.

Diazocaffeine couples readily not only with a large number
of aromatic compounds but with aliphatic as well. It com-
bines with acetoacetic ester and the free acid, with their
horaologues, with nitroethane, nitropropane, etc.

Ever since V. Meyer's' discovery of the action of diazoben-
zene upon acetoacetic ester, this same question has been re-
peatedly the subject of investigations. The derivatives
obtained by this reaction are no longer looked upon as azo
bodies, — a view originally entertained by the discoverer, — but
rather as hydrazones. This change of view as to the consti-
tution of these and all analogous bodies is due especially to
the work of R. Meyer, '^ of Japp and Klingemann,^ and to the
more recent investigations of Bamberger and of Von Pech-
mann upon the constitution of the formazyl derivatives. It
has been established that whenever a diazo salt combines with
an aliphatic compound containing a methylene or a methine
group, made negative by carbonyl or nitro groups, the deriv-
atives so obtained do not possess the expected azo constitu-

1 Ber. d. chem. Ges., lo, 2075.

2 Ibid., 21, 118 ; 24, 124.1.

8 Ann. Chem. (r,iebig), 247, 190.

54 Gomberg.

tion, but suffer an intramolecular change to the h3'drazones :

CH3 CH3'

I I

CO CO

I 1

CH— N : N.Ph — * C = N.NHPh.

I i

COOR COOR

CH, CH3

I I

CO CO

I t

CH— N : N.Ph — CH=N.NHPh

I + CO,.

COOIH

So great is this tendency to change into hydrazones, that if
an alkyl acetoacetic ester is employed in this reaction then
one of the two negative groups — the acetyl or the carboxyl, de-
pending upon the conditions of the experiment — is entirely
split off in order to allow the formation of such a hydrazone :'
CH3 CH,^

I I

CO COOH

CH3— C— N : N.Ph — * CH3— C=N.NH.Ph

I I

COOR COOR

CH3 CH/

I I

CO CO

t I

CH3— C— N : N.Ph — > CH3— C=N.NHPh
I +C0,

COOH
The recent investigations of Bamberger,* Von Pechmann,®

1 Billow, in a recent article (Ber. d. cheni. Ges., 32, 197) stiU maintains that in
case of acetoacetic ester and some diazo salts true azo bodies result. A similar con-
stitution is ascribed by him to benzoylacetone. Ibid., 2637.

'^ Billow's diacetylsuccinic ester seems to form an exception to this rule. Ber. d.
chem. Ges. 32, 2SS0.

s Japp and Klingemann : Ann. Chem. (Liebig), 247, 20S.

i /^z'rf., 247, 21S. Also, for instance, in the action of diazobenzene upon cam-
phoric acid (Betti : Ber. d. chem. Ges., 32, 1995).

5 Bamberger and Wheelright : Ber. d. chem. Ges., 25, 3201 ; Bamberger : Ibid.,
3547- ^ Ibid.. 25, 3175.

Diazocaffeine . 55

Claisen,' and Wislicenus^ show, however, that under certain
conditions a second diazo molecule can be introduced into
these and similar compounds, and a class of bodies — the
formazyl derivatives — is obtained which contain both the
hydrazone and the azo constitution. In case of acetoacetic

^N.NH.Ph
ester we get either acetylformazvl, CHjCO.C^ , or

\N:N.Ph
^N.NH.Ph

formazylformic ester, C — COOR , the nature of the prod-

^NrN.Ph

uct being governed by the conditions of the experiment. In
presence of a large excess of alkali, even a third molecule of
the diazo compound can be introduced, and thus only one car-
bon atom is left of the whole chain of the acetoacetic ester :

/.N.NH.CeH, '
CeH.N : N.C:^

It is unnecessary to enter here in detail upon the behavior
of the formazyl derivatives, so thoroughly studied by Bam-
berger, Von Pechmann, and especially by Wedekind.

The body which I have obtained by the action of diazo-
caffeine upon acetoacetic acid resembles in appearance so
strongly the formazyl compounds, that at first thought it was
taken for such. It was considered rather unusual that a
formaz\'l-iike body should be formed to such a large extent in
an acid solution, especially when the acetoacetic acid was
alwaj-s in excess. Instead of a pale to an orange-j-ellow hy-
drazone a body of dark-blue to violet color was obtained in
every instance, with a beautiful metallic luster and having the
appearance either of fuchsin or of methyl-violet. It possesses
intense coloring properties and shows characteristic color re-
actions in cold and hot water, not unlike those peculiar to
cobalt salts. The results of elementary analysis of several
samples point, however, to a formula different from what a

1 Ber. d. chem. Ges., 25, 746. 2 Ibid., 25, 3453.

3 This benzeneazoformazyl is the end-product of the action of diazobenzene upon
a large number of compounds containing either the CH3.CO group, or the CHj group
linked to two negative radicals which can be split off more or less readily by
hydrolysis.

56 Gomherg.

caffezyl body would require. Instead of the caffezylmethyl-
ketone,

I
CO

I ^N.NH.C,H,NA

the analytical results point rather to a disazo body ;

CH3

I
CO

I /N : N.C,H,NA

y\N : N.C,H,NA-

COOH
Such a reaction has, to my knowledge, been observed only
once.'

Propyl and benzylacetoacetic acids were next taken for this
reaction, with the expectation that in this case monoazo
bodies would result. But here, too, judging from the results
of analysis, disazo compounds were formed, at the expense of
the acetyl group :

CH3 CH3

I I

CO COOH

I N • N C H N O

^'^' I ^^-"^ |N:N.C,H,N,0/

COOH COOH

CH3 CH,

I I

CO COOH

I N • M C H N O

^''■"' I ^'-^^ Vn : N.C^H.N.O/

COOH COOH

All these dyes, while not at all, or only slightly, soluble in
water, dissolve in dilute alkalies, even in solutions of sodium
carbonate, a fact which points to the presence of a carboxyl

1 Unfortunately, the exact reference has escaped me for the present.

Diazocaffeine . 57

group. While they dissolve in concentrated sulphuric acid,
some with reddish, and some with yellowish-green color, none,
however, gives on the addition of ferric chloride or of potas-
sium dichromate the blue or violet of Billow's reaction, so
characteristic of all the hydrazones and consequently of the
formazyl derivatives. And yet, notwithstanding all these
facts, I should still be of the opinion that we have here to
deal with formazyl-like bodies had it not been for the follow-
ing consideration :

Bamberger' has shown that the constitution assigned by V.
Meyer to the so-called mixed nitroazoparaffins is correct only
in cases in which the diazo molecule is linked to a tertiary
carbon atom. In all other cases they, too, must be considered

/NO,

as hydrazones.^ Thus, nitroethane forms CHgC^^ ,

^N.NH.Ph
while z-nitropropane gives, under similar conditions,

CH3C— NO,

^N : N.Ph

And as the NO, group, unlike the acetyl or the carboxyl,
cannot be split off under the conditions of the experiment,' it
follows that of all the nitroparaffins nitromethane alone can
give rise to formazyl derivatives. In fact, nitroformazyl,

^N.NH.Ph
NO, — C<^ , is the principal product of the interac-

\N : N.Ph

tion of diazobenzene and nitromethane. The yellow hydra-
zone can be obtained only by observing special precautions.

Diazocaffeine, however, gives in alkaline solutions with
nitroethane and nitropropane, compounds which resemble in
appearance and in the characteristic color reactions so closely
the body obtained from acetoacetic acid as to leave no doubt
that the nature of the reaction must be the same in both cases.

1 Ber. d. chem. Ges., 27, 155.

^NO.ONa

2 The salts have a true azo constitution, as CHsC^ . Bamberger : Ber.

\n : N.Ph
d. chem. Ges., 31, 2626.

^ The NO5 group in the azoparaffins can be removed by hydrolysis by means of
alkali when heated. Bamberger : Ibid., 2630.

58 Gombcrg.

But, as neither nitroethane or nitropropane can, according to
Bamberger, give rise to formazyl derivatives — caffezyl com-
pounds in this case — it must be concluded that the dyes from
acetoacetic acid also, which resemble so markedly the above
nitro compounds, are not caffezyl compounds. It must, how-
ever, be remembered that the elementary analysis of the nitro
bodies, while pointing to a disazo formula, did not give satis-
factor}' results in the case of carbon and hydrogen. Whether
this was due to insufficient purification of the small amount
of material at hand, or as in Bamberger's experience,' to the
marked tendency of these bodies to form oxides of nitrogen
during combustion has not yet been determined.

It is hoped that further study of the action of diazocaffeine
upon aliphatic compounds will help to clear up the nature of
the reaction.

Diazocaffei7ie Hydrochloride.

After many trials it was found that amidocaffeine can best
be diazotized when dissolved in concentrated hydrochloric
acid, because the base is only very slightly soluble in dilute
acids, and even when in ver}^ fine suspension, is only slowly
attacked by nitrous acid. Amidocaffeine" is dissolved in five
times its weight of hydrochloric acid (sp. gr. 1.20) and the
solution is well cooled in a freezing-mixture to about — 18° C.
The calculated quantity of sodium nitrite, dissolved in about
four to five times its weight of water, is very slowly run into
the bottom of ^.he dish containing the amine, the solution be-
ing vigorously stirred by means of a turbine. The tempera-
ture is best kept down to — 10° C. The foam on the surface
of the solution can be broken up by the occasional addition of
a few drops of alcohol. The strongly yellow solution, de-
canted from the solid sodium chloride which separates during
the reaction will remain clear for over an hour, if kept in a
freezing-mixture. But if the temperature is allowed to rise, a

1 Ber. d. chem. Ges., 27, 157.

2 The amido compound was prepared according to E. Fischer's method [Ann.
Chem. (Liebig), 215, 265]. The heating under pressure was done in autoclaves, by
placing in it a large test-tube containing the chlorocaffeiue and alcoholic ammonia.
Ordinary packing, such as asbestos, rubber, graphite, etc., would not stand. Strips
of sheet-lead gave very good satisfaction. In this manner 20 grams of the halogen
compound could be used in one operation, and the j'ield was 17-18 grams of pure
amidocaffeine. The temperature of the oil-bath was kept at i5o°-i6o'.

Diazocaffeine . 59

gas, probably nitrogen, is evolved, and a small quantit}' of
very bulky amorphous decomposition-product separates out.
The clear solution shows all the reactions of a diazo com-
pound. All the efforts to obtain it in the form of some insol-
uble salt — as chromate, picrate, or cyanide' — proved fruitless.
Attempts to reduce it by stannous chloride to a hydrazine
were equally unsuccessful. The solution of the diazo salt
stains the skin dark-red, quickly changing to brown, which
remains permanent for some days.

Apparently the same diazo compound is produced by the
action of nitric acid upon amidocaffeine in the cold. This is
probably due to a partial reduction of the nitric to nitrous acid.

Caffeine-p-azophenol, C,H,NA-N : N.CsH^COH) (;^).— Di-
azocaffeine couples W'ith phenol in both acid and alkaline
solutions, in water or in alcohol. The solution of the diazo
salt in hydrochloric acid can at once be added to an ice-cold
solution of phenol in water. The azo compound separates
immediately as a dark-yellow to an orange mass, resembling
in its appearance freshly precipitated ferric hydroxide. The
mixture is allowed to stand about an hour, filtered, washed,
and dried on a porous plate. The almost black pow^der is
best recrystallized from a large quantity of glacial acetic acid,
from which it can be obtained, on slow cooling, in beautiful
red needles reflecting light strongly. For anal5'sis it must be
recrj'stallized several times from the same solvent in order to
free it entirely from some of the disazophenol, which, as could
be judged from the high percentage of nitrogen, was also
formed to some extent in the same reaction.

I. 0.1862 gram substance gave 0.3650 gram CO^, and 0.0778

gram H,0.
0.1744 gram substance gave 40.4 cc. N at 21°. 5 C. and
743.5 mm.

II. 0.1409 gram substance gave 34.7 cc. N at 26° C. and

731.7 mm.

Calculated for Found.

C8H8X402.N3.C8H40H. I. II.

C 53-50 53.52

H 4.46 4.64 . • ..

N 26.75 26.52 27.26

1 .\na. Chem. (Liebig), 305, 64.

6o Gomberg.

The dye is insoluble in cold water and only slightly when
heated. It dissolves in dilute alkali hydroxides and carbon-
ates with a deep-red color. Alcohol, even on boiling, takes
up only traces of the dye forming yellow solutions. The
same is true of chloroform. It is insoluble in ether and ben-
zene. Glacial acetic acid and nitrobenzene are the best sol-
vents for this substance. Concentrated sulphuric acid dis-
solves the dye with a deep-red color, which instantly changes
to an intense violet-blue ; this color is changed to a pale-yel-
low by a drop of potassium dichromate solution, but ferric
chloride imparts to it a greenish tint. A slightl}^ alkaline
solution of the azo body dyes unmordanted cotton pink,
which is discharged by acids, but is brought back by soap
solutions.

Caffeine-p-azodimethylaniline ,
C,H,N,0,.N : N.C,H,N(CH3),(/).— Diazocaffeine combines
with dimethylaniline even in the presence of hydrochloric
acid. A better yield of the dye is, however, obtained when a
solution of the diazo salt in concentrated hydrochloric acid is
slowly added to a cold solution of the calculated quantity of
dimethylaniline, to which suflScient sodium acetate has been
added to take up all the hydrochloric acid. The solution of the
dimethylaniline is best cooled by introducing ice directly into it.
After standing for from one to two hours the mixture is gently
heated on the water-bath until the apparently amorphous pre-
cipitate assumes a decidedly crystalline appearance. Ten
grams of amidocaffeine gave in this way 9 grams of the azo
body. For further purification the dye is recrystallized from
boiling chloroform, from which it comes down almost com-
pletely on the addition of a very small quantity of ether. The
long, dark-red needles, of a beautiful greenish iridescence,
were again redissolved in chloroform, and the concentrated
solution, while hot, was slowly poured into boiling toluene.
The dye is at once precipitated in the form of dark steel-blue
needles. A portion of this was then recrj^stallized from a
large quantity of toluene.

I. From toluene: 0.1550 gram substance gave 0.3204
gram CO^, and 0.0828 gram H^O.

Dia zocaffein e. 6 1

0.1698 gram substance gave 43.9 cc. N at 25° C. and
745.5 mm.

II. From chloroform and toluene: 0.1865 gram substance

gave 0.3885 gram CO^, and o.iooi gram H3O.
0.1916 gram substance gave 49.4 cc. N at 24° C. and
745.5 mm.

III. From chloroform alone : 0.1650 gram substance gave
42 cc. N. at 25° C. and 739 mm.

Calculated for

Found.

C8H9N4OJ Nj.C.H<N(CH,),,.

I.

II.

C 56.30

56.37

56.80

H 5.57

5-93

5-96

N 28.73

29.18

29.19

28.48

This azo compound can be obtained, as mentioned above,
either in cherry-red crystals with a green reflection or in the
form of steel-blue needles, or as bluish-red, shining crystals.
It is hardly at all soluble in water, dissolves only slightly in
dilute, but fairly readily in glacial acetic acid. It is only
sparingly soluble in alcohol (red solution), or benzene, not at
all in ether. It dissolves in dilute mineral acids forming a
deep-red solution. Concentrated sulphuric acid dissolves it
with a yellowish-green color, while concentrated hydrochloric
acid forms a deep-green solution. The hydrochloride of the
base was prepared by dissolving the body in chloroform and
passing gaseous hydrochloric acid into the solution. It is a
fairly stable salt when dry, but easily decomposed by water.

It dissolves in pure chloroform with a clear red color. But
when the chloroform is contaminated with certain impurities
then it dissolves the dye with a distinct violet color. Sev-
eral samples of chloroform on the market responded to
this test, giving violet solutions, but on purification gave the
red solutions. I was unable to find out just what impurities
cause this change in color. Experiments have shown that it
is not due to traces of hydrochloric acid, alcohol, or carbon}^
chloride.

Reduction with Stannorcs Chloride.

Two grams of the dimethylaniline dye were dissolved in
concentrated hydrochloric acid, and to this solution, while
hot, a solution of stannous chloride (10 grams in 20 cc. of

62 Go7nberg.

concentrated hydrochloric acid) was added drop by drop until
the green color was completely discharged. The solution
was then diluted with water to about 300 cc. and the acid
partially neutralized. In about an hour the amidocaffeine sep-
arated in the form of a white granular powder. It was
washed with dilute acid (in which it is almost insoluble),
alcohol, and ether. The yield was nearly i gram. For
analysis it was recrystallized from glacial acetic aci.l.

0.1643 gram substance gave 50.2 cc. (moist) N at 19°. 5 C.
and 742 mm.

Calculated for

C8H9N4O2NH5. Found.

N 33.50 33-82

The filtrate from amidocaffeine was shaken out with ether,
and the residue obtained on evaporating the latter was tested
in the usual way for/>-amidodimethylanilineby means of hydro-
gen sulphide and ferric chloride. The characteristic methyl-
ene blue was thus obtained.

The reaction with stannous chloride is therefore to be rep-
resented by the equation :

C,H,NA-N : N.C6H,N(CH3), + 4H =

C,H,NANH, + NH,C,H,.N(CH3),.

Caffeineazo-2 ,^-dia m idoben zene^
/NH, {0)
CeH,N,0,.N : N.C^Hj^ .—The diazo salt couples

\NH, ip)
very readily with metaphenylenediamine. The reaction
was carried out in presence of sodium acetate. The bulky
chocolate-brown precipitate becomes almost black on drying.
It was recrystallized from glacial acetic acid and analyzed
with the following results :

0.1620 gram gave 48.9 cc. N at 26°. 5 C. and 736.5 mm.

Calculated for
CgHjN403.N2.C6Ha(NH5)3. Found.

N 34-15 33-54

It is of a brown color. It is only slightly soluble in the

usual organic solvents. Hot glacial acetic acid is the best

solvent for it. It does not melt at 285" C. It dissolves in

dilute mineral acids with an intense reddish-brown color.

Dia zocaffein e. 63

Caffeineazo-fi-7iaphthol, C,H,N,0,.N : N.C,„H,OH. — Five
grams of amidocaffeine were diazotized in the usual manner
and added to the theoretical amount of /5-naphthol in 500 cc.
of a 4 per cent solution of potassium hydroxide. The sep-
aration of the azo body begins at once, and is greatly ha-
stened and increased by saturating the solution with salt. It
was filtered and washed with a solution of salt. On the ad-
dition of dilute mineral acid to a warm solution of the alkali
salt of the uaphthol compound, the free azonaphthol separates
in the form of brown flakes mixed with an oil, which on
further warming and stirring changes all to a granular pre-
cipitate. It was then filtered, washed, first with water then
with alcohol and ether, to remove any free /5-naphthol, and
finally dried on a porous plate. The yield was 6 grams. For
analysis the substance was recrystallized from glacial acetic
acid ; the crj^stals were collected in two separate crops, the
first consisting of minute ponceau-red needles, the second
crop being of a somewhat lighter color.

I. 0.2324 gram substance gave 0.5007 gram CO,, and 0.0976

gram H„0.
0.2071 gram substance gave 41.4 cc. N at 24° C. and
735.5 mm.

II. 0.1589 gram substance gave 33.9 cc. N at 25°. 5 C. and

733 mm.

Calculated for Found.

C8H|,]Sr402.N2.C,oH,;OH. I. II.

C 59.34 48.82

H 4.40 4.66 • . . .

N 23.08 22.56 23.63

The dj'e, insoluble in water, dissolves slowl3Mn a cold solu-
tion of sodium carbonate, more rapidly when heated ; is solu-
ble in dilute hot alkali hydroxide, forming a deep-red solution.
Alcohol dissolves it only slightly, with a violet-blue color ; it is
insoluble in ether, but dissolves in hot benzene and chloro-
form with a deep-red color. It dissolves in concentrated sul-
phuric acid, giving a deep- blue solution, which is intensified
by a drop of a solution of ferric chloride, but is discharged by
potassium dichromate. This reaction with ferric chloride re-
minds one in its play of colors of Billow's reaction for hydra-

64 Gomberg.

zones — a structure sometimes ascribed to ox5'azo compounds.
Reaction with Acetoacetic Acid.

Diazocaffeine couples with acetoacetic ester and the free
acid, in alkaline solutions, as well as in presence of acetic
acid, and even in hydrochloric acid solutions.

After many trials the following method was adopted : 6.5
grams (i molecule) of the ester are dissolved in about 100 cc.
of dilute potassium hydroxide containing 3 grams (i mole-
cule) of the alkali, and allowed to stand twenty-four hours for
complete saponification. 10.5 grams (i molecule) of amido-
caffeine are diazotized in the manner above described, and
slowly added to the well-cooled, slightly acidulated solution
of the acetoacetic acid, to which about 100 grams of sodium
acetate and 300 cc. of water has been previously added. On
the first addition of the diazo solution a noticeable evolution
of gas takes place, but this soon stops. The azo compound
separates at once as a bulky, dark-brown precipitate, which
completely fills the beaker. The mixture is allowed to stand
in ice about two hours. Salt is then added to saturation, and
the solution is gently warmed on the water-bath, whereby the
precipitate becomes granular and is easily filtered. On
washing, however, with distilled water it swells up again,
and can then be filtered only with difficulty. The precipi-
tate, dried on a porous plate, presents a green to blue irides-
cence, and not infrequently possesses the metallic copper lus-
ter of malachite-green. The yield is about 5 grams. It can
be recrystallized either from glacial acetic acid or from chlo-
roform. When to the warm solution of the dye in glacial
acetic acid a few drops of alcohol or ether are added, it be-
gins to come down at once in the form of a gelatinous, stringy
mass, which very soon changes to lumps of dark-blue crystals
with a decided green reflection. Alcohol also helps in the
crystallization of the substance from chloroform.

I. From glacial acetic acid : 0.2968 gram substance gave
0.4869 gram CO^, and 0.1214 gram H,0.
0.1987 gram substance gave 55.5 cc. N at 24° C. and
734.7 mm.

Diazocajffeine. 65

II. From chloroform : 0.2765 gram substance gave 0.4472
gram CO^, and 0.1105 gram H^O.
0.1627 gram substance gave 48 cc. (moist) N at 27° C.
and 737 mm.

Calculated for Found.

y

C0CH3

(CbH9N402N5),C<

^COjH

-\f

C 44-28 44.73 44.15

H 4.06 4.55 4.44

N 31.00 31.12 31.55

The acetoacetic acid compound possesses, as mentioned above,
a beautiful dark-green, cantharidine-like luster. It is some-
what soluble in water, dissolving slowly, and forming a red-
dish-violet solution. On boiling the solution turns deep-blue,
of almost the same shade as Fehling's reagent. . On cooling
the original color comes back. The same changes of color
are more marked in dilute solutions of sodium carbonate or
hydroxide, in which the dye dissolves, forming intensely col-
ored solutions. It is only slightly soluble in alcohol and
benzene, with a pure blue color in the first and a violet-blue
in the second. It is fairly soluble in chloroform, and here
again the color of the solution is violet-blue. The phenomena
of change of color in hot and cold solutions are much more
marked in the case of nitroethane and nitropropane com-
pounds. The azo compound shows slight signs of melting at
about 200° C, but no further melting is noticeable even at
285° C.

As regards Billow's reactions, the substance dissolves in
concentrated sulphuric acid with a red color, which is not
changed either by ferric chloride or potassium dichromate.

Reaction with Propylacetoacetic Acid.

Eight and six-tenths grams (i molecule) of propylaceto-
acetic ester mixed with 3 grams ( i molecule) of potassium
hydroxide in 100 cc. were allowed to stand twenty-four hours
for complete saponification. To this dilution, diluted to
about 500 cc. and well cooled, the hydrochloric acid solution
of 10.5 grams (i molecule) of diazotized amidocaffeine was
slowly added. Considerable foaming took place at the be-
ginning. The separation of the azo compound greatly in-

66 Gomberg.

creased on the addition of about loo grams of sodium ace-
tate to the dark-red solution. The mixture, after standing
for some time, was saturated with salt and warmed for a short
time on the water-bath. The precipitate became granular
and was easily filtered. It was washed with a little water
and dried on a porous plate. An attempt to remove all the
inorganic salts by suspending the well-dried dj'e in cold
water (a treatment successfully employed with other dyes in
this work) gave a gelatinous thick mass which proved al-
most impossible to filter. The yield of the dr}' substance,
well washed with ether, was about 2.8 grams. The substance
was dissolved in hot chloroform and to the filtered concentra-
ted solution one-half its volume of ether was added. The
crop of crystals which separated in a few hours was recrj's-
tallized from glacial acetic acid with the addition of a little
alcohol.

0.2493 gram substance gave 0.4217 gram C0„, and 0.1205
gram H„0.

0.2054 gram substance gave 55.4 cc. N at 21°. 5 C. and 738
mm.

Calculated for

(C8HsN402N5),C<^ ^ ' . Found.

^COOH

C 46.49 46-17

H 4.80 5-37

N 30.09 30.91

It is a dark-brown crystalline powder with a bluish tint,
but lacks the metallic luster of the acetoacetic acid compound.
It is very slightly soluble in water, but readily in alkali car-
bonates and hydroxides — in all cases with a yellow-green
color which does not change on boiling. Dilute mineral
acids take up small quantities of this azo compound forming a
red, cobalt-like solution. The dye is only slightly soluble in
benzene, giving a bluish-red solution, while to chloroform, in
which it is fairly soluble, it imparts a reddish-violet color. It
does not melt at 285° C.

It dissolves in concentrated sulphuric acid, forming a red
solution which is not affected by ferric chloride, but is dis-
charged by potassium dichromate.

Diazocaffeine . 67

Reaction with Benzylacetoacetic Acid.

The reaction proceeds as with the propylacetoacetic acid
but less smoothly. As this ester is not saponified readily, the
alkaline solution, after standing twenty-four hours, was
gently warmed for a short time to about 50° C, acidulated and
filtered from the unsaponified ester. The coupling was done
in presence of sodium acetate. There was considerable
foaming on the addition of the diazo salt. There was some
flocculent precipitate mixed with a considerable amount of a
black oil. It was filtered, thoroughly washed with water,
dried on a porous plate, and washed directly on the plate with
ether. The dull-black powder was recrystallized twice from
chloroform with the addition of ether. The precipitate, at
first amorphous, becomes crystalline on standing. The yield
of the pure substance was 0.5 gram from 10 grams of amido-
caffeine.

0.1802 gram substance gave 0.3320 gram CO,, and 0.0792
gram H,0.

0.1872 gram substance gave 49.6 cc. (moist) N at 22° C.
and 737 mm.

Calculated for

(CgHsN,02N,,),C<f ' ' . Found.

^COjH

C 50.84 50.30

H 4.40 4.88

N 28.47 29.07

This body resembles in its solubility very much the propyl
derivative, giving yellow to yellow-green solutions. In
Billow's reaction it is almost identical with the propyl com-
pound. It does not melt at 285° C.

Reaction with Nitroethane.

The diazo salt was added to a well-cooled solution of an ex-
cess (1.5 molecule) of nitroethane in about 700 cc. of water
containing enough potassium hydroxide to neutralize all the
hydrochloric acid of the diazo solution. After standing for
some hours the precipitate was filtered off from the dark
cherr\--red solution, and was well washed with water. The
dry substance was dissolved in hot chloroform and the filtered

68 Gomberg.

solution concentrated. The crystals, consisting of deep-blue
flakes, were filtered, washed with a mixture of chloroform and
ether, and recrystallized once more in the same way. The
melting-point remained constant , 2 1 8°-2 1 9° C . Seven grams of
amidocaffeine gave about 0.5 gram of the purified dye. The
results of analysis are given below, although the carbon and
hydrogen are considerably higher than theory for a disazo body
requires. I hope to obtain larger amounts of th^s body, and
establish its composition more exactly.

I. 0.1241 gram substance gave 0.2023 gram CO^, and 0.0604

gram H,0.
0.1442 gram substance gave 45.8 cc. N at 22° C. and 739
mm.

II. 0.1224 gram substance gave 38.9 cc. N at 23° C. and

739 mm.

Calculated for Found.

/CH,

(C8HbN40jN2)5C< . I. II.

^NOj

C 41-94

H 4.08

N 35-34

The nitroethane derivative presents some very peculiar
color reactions, similar in nature to those of the acetoacetic
acid derivative but more pronounced in character. While in-
soluble in cold water it dissolves on boiling, giving a deep-blue
solution, not unlike that of an ammoniacal copper solution.
On cooling, the solution first becomes violet and finally almost
entirely red. On reheating, the same phenomena can be ob-
served. This change of color from red to blue and conversely
is even more pronounced in dilute alkali solutions, in which
the dye is only slightly more soluble than in water. The sub-
stance is insoluble in ether, very slightly in benzene (blue
solution), readily soluble in chloroform with an intense blue
color, and dissolves also in glacial acetic acid, forming a red
solution.

Dissolved in concentrated sulphuric acid it gives, like
formazyl derivatives,' a red solution, which, however, does
not change, on standing, into a violet of Billow's reaction, as

1 Wedekind : Ber. d. chem. Ges., 30, 2995.

44-50

....

5.41

(?),...

35-90

35.80

Diazocaj^eine. 69

nitrohydrazones do through intramolecular oxidation;' nor
does ferric chloride or potassium dichromate bring about this
change into the blue or violet.

Reaction with Nitropropane .

The reaction was carried on under the same conditions as
with nitroethane. The brown precipitate, after washing and
drying, was recrystallized twice from chloroform with the ad-
dition of ether and obtained in the form of very light, deep-
blue flakes with a slight metallic luster, and melting with de-
composition at 237°-238° C. The yield was again small.
Ten grams of amidocaffeine furnished about 0.7-0.8 gram of the
purified product. The carbon and hydrogen are considerably
higher than the theory for a disazopropane requires. What
was said under nitroethane applies equally well in this case.

0.2488 gram substance gave 0.4189 gram CO^, and 0.1186
gram H,0.

0.1415 gram substance gave 44 cc. N at 21° C. and 739 mm.

Calculated for

/CjHs
(C8H,N40jN2)2C< . Found.

^NOj

C 43-29 45-95

H 4-35 5-29

N 34.40 35.26

This body is somewhat more soluble in all the solvents than
the corresponding nitroethane derivatives. It shows the same
peculiar color reactions when its solution in water or dilute
alkalies is heated, giving, when hot, a deep-blue solution,
which, on cooling, assumes a lavender color.

■ Towards concentrated sulphuric acid and oxidizing agents
it behaves exactly like the nitroethane compound.

Chemical Laboratory,

University of Michigan,

July, 1899.

1 Bamberger : Bar. d. chem. Ges., 31, 2631.

THE ACTION OF ETHYL IODIDE ON TARTARIC
ESTER AND SODIUM ETHYI^ATE.

By John E. Bucher.

Introduction.

By the action of the ethylate of sodium or of potassium on sym-
metrical dibromsuccinic ester (m. p. 58°), a number of inves-
tigators have obtained diethoxysuccinic ester. The sym-
metrical constitution for this compound seems to have been
generally accepted. Michael and Bucher,' however, showed
that it consists mainly of the uusymmetrical diethoxysuccinic
ester. They also obtained the same ester by the addition of
sodium ethylate to several unsaturated compounds. In no
case did they prove the presence of the corresponding sym-
metrical ester. The following investigation was undertaken
with the object of preparing the symmetrical ester and acid
so that their properties might be studied.

One of the most obvious methods seemed to be the action
of ethyl iodide on disodium tartaric ester. The literature on
the subject was not found to be favorable to this method.
Meyer and Jacobson,^ in speaking of the esters of tartaric
acid, make the following statement : " Die Wasserstoffatome
der alkoholischen Hydroxylgruppen konnen in diesen Estern
durch Natrium und Kalium ersetzt werden ; die so entste-
henden Alkoholate, wie C,HJOK),(CO,C,HJ,, sind zu dop-
pelten Umsetzungen indessen nicht brauchbar." Reference
is made to the work of Perkin, I^assar-Cohn, and Mulder.
As the original articles, except that of Eassar-Cohn,^ were not
accessible, it was necessary to rely on abstracts in the Chem-
isches Central-Blatt. In these abstracts no mention is made
of the fact that Perkin" has studied the action of ethyl iodide
and bromide on the above sodium or potassium derivatives.
Eassar-Cohn, however, states that Perkin supposed he had
probably replaced the sodium in sodium tartaric ester by this

1 Preliminary articles : Ber. d. chem. Ges., 38, 2511 ; 29, 1792.

2 Lehrbuch d. organisclien Chemie, p. 805.

3 Ber. d. chem. Ges., 20, 2003.

4 Chem. Centrbl., 1867, p. 593.

Action of Ethyl Iodide. 71

method. Lassar-Cohn found that no reaction took place on
treating the monosodium derivative with methj'l iodide or
ethyl bromide. The disodium derivative proved to be equally-
inactive. From these observations he concluded that Perkin
probably mistook tartaric ester, regenerated by the action of
moisture, for the expected ethoxy derivative. More recently
Mulder' has published a number of long papers on the action
of ethyl chloride on disodium tartaric ester. From the ab-
stracts it appears that he was entirely unsuccessful in prepar-
ing diethoxysuccinic ester but that a ketone ester was ob-
tained.

Apparently, the above investigators used the dry sodium or
potassium derivatives. It was thought that the reaction
might take place in alcoholic solution. A preliminary ex-
periment showed this to be the case, an oil being obtained
which was not soluble in alkalies and which gave no color re-
action with ferric chloride. After having prepared diethoxy-
succinic ester and obtained several salts from it, the abstract
of an article by Purdie and Pitkeathly^ appeared. They had
obtained the symmetrical diethoxysuccinic ester by the action
of ethyl iodide on tartaric ester and silver oxide. In view of
their work, it has seemed desirable to publish the results thus
far obtained, although the work is still in progress.

EXPERIMENTAL PART.

One experiment will be described in detail, so that only the
variations need be mentioned in the others. To a cooled
solution of 27 grams of sodium (25 grams = 2 atoms) in 340
cc, of absolute alcohol 112.5 (2 mols.) grams of tartaric ester
and 245 grams of ethyl iodide were added. The solution was
boiled with a reflux condenser for twelve hours. The clear
solution soon became colored yellow and later red. The red
color was not due to the separation of iodine. Carbon diox-
ide was now passed into the solution, which was very faintly
alkaline. The alcohol and excess of ethyl iodide were then
distilled off on the water-bath. The residue, after the addi-
tion of water, was extracted with ether. This extract was

iChera. Centrbl., 61, 467; 622, 442 : 63, 5S7; 645,529,644; 66,531; 67,,:97;67,,
345-

2 Ibid., 70, 779.

72 Bucket.

then shaken violently for one-half minute with a solution of
caustic alkali to remove any tartaric and ketone esters. The
extract was dried with calcium chloride and the ether dis-
tilled off on the water-bath. In this way 60 grams of crude
product were obtained as a slightly yellowish- red oil.

A part of the aqueous solution, which had been extracted
with ether, was acidified and again extracted. So much hy-
driodic acid was dissolved by the ether that it turned
red rapidly from the separation of iodine. This interfered so
much that the viscous oil thus obtained was not examined.
A solution of calcium chloride was added to the remainder of
the aqueous solution. A large quantit}^ of a white precipitate
was obtained which was shown to be mainh^ calcium tartrate
(or racemate). The above 60 grams of crude ester were dis-
tilled under diminished pressure with a column of beads, using
the method described by Michael.' About 0.9 of the product
came over between i34°-i4o° at 11.5 mm. The first few cc,
being colored by free iodine, were rejected. There was some
decomposition at the end of the distillation, about i gram of
residue remaining in the flask. On redistillation the greater
part boiled at 131°. 5-136°. 5 at 10.5 mm. It was found to
contain 53.86 per cent of carbon and 8.10 per cent of hydro-
gen.

The experiment was repeated many times, varying the con-
ditions and the quantities of the reacting substances. Usually
about 2.2 molecules of ethyl iodide were used to each mole-
cule of tartaric ester. In some cases the excess of absolute
alcohol was driven from the sodium ethylate by drying in
vacuo at 230", and the tartaric ester and ethyl iodide were
added to the dry solid. In a few experiments the solution of
sodium ethylate was allowed to flow into the boiling mixture
of tartaric ester and ethyl iodide. In a few of the earlier ex-
periments the ether extract was not shaken out with caustic
alkali, but this was not neglected after finding much tartaric
(or racemic) ester in the product, when using one atom of
sodium per molecule of tartaric ester. The shaking was not
continued more than one-half minute, using a 5 per cent solu-
tion of caustic alkali. In one experiment no heat was ap-

1 J. prakt. Chem., N. F., 46 Nachtrag.

Actio7i of Ethyl Iodide. 73

plied, the substances being allowed to stand at the room tem-
perature for two weeks. The quantit}' of sodium varied from
I to 2.2 atoms per molecule of tartaric ester. The 5-ield of
crude product varied between 50 and 60 per cent of the
weight of the tartaric ester used. Evidently other reactions
interfere, so that only about one-half of the calculated yield
of crude ester is obtained. The products distilled under di-
minished pressure, with a column of beads, did not have a
constant boiling-point, the range being from 4° to 10°. Analy-
ses of the above products showed that, although the yield was
fairly constant, the composition varied very much, the per-
centage of carbon in the various fractions varj-ing from 51.8
to 54.9 per cent.

Calculated for Calculated for Calculated for

C5H2(OC.2H5)o(CO.,CjH5)5. CoH,(OH)(OC2Hs)(COjC,H5)j. C3H,(OH).,(CO,C2H5),.

C 54.89 50.75 46.60

H 8.40 7.60 6.80

When from I to i.i atoms of sodium per molecule of tar-
taric ester were used, the average composition of the fractions
was 52.4 per cent of carbon, and when from 2 to 2.2 atoms
were used, the average was 54.3 per cent of carbon. As the
fractions analyzed did not represent the entire j'ield, the fol-
lowing additional experiments were made. The entire prod-
uct was collected in one fraction, only about 5 per cent being
lost at each end of the distillation.

Experiment a. — To 5 grams (i atom) of sodium dissolved
in 60 cc. absolute alcohol, 45 grams (i mol.) of tartaric ester
and 130 grams of ethyl iodide were added. After boiling five
hours with a reflux condenser the alcohol and excess of ethyl
iodide were distilled off on the water-bath. Water was added
to the residue and the mixture extracted with ether. The
ether extract w^as shaken out with caustic alkali for one-half
minute. The yield of crude product was 23 grams, boiling at
i46°-i50° at 17 mm. [«^]d was + 31° at 20°.

Experiment b. — Proceeded exactly as in Experiment a, ex-
cept that the quantities were as follows : 8 grams (1.07 atoms)
of sodium, 100 cc. of absolute alcohol, 67.5 grams (i mol.) of
tartaric ester, 150 grams of ethyl iodide, crude product 36
grams (=53 per cent of the weight of tartaric ester). The

74 Bucher.

time of boiling was seven hours, and the ester distilled at
i45°-i50° at i6 mm. [«^]d was +24° at 20°.

Experiment c. — Proceeded as in Experiment a, except that
the quantities were as follows : 15 grams (3 atoms) of sodium,
180 grams of absolute alcohol, 45 grams (i mol.) of tartaric
ester, and 150 grams of ethyl iodide. The yield of crude
product was 20 grams, or 44 per cent of the weight of the tar-
taric ester. It boiled at i44°-i47° at 17 mm. [«^]d was
-1-1.1° at 20°.

Analyses of these three preparations gave the following re-
sults :

a, I. 0.2269 gram substance gave 0.4379 gram CO,, and
0.1637 gram H„0.

b,\. 0.2042 gram substance gave 0.3954 gram CO,, and
0.1486 gram H,0.

b,\\. 0.2170 gram substance gave 0.4199 gram CO^, and
0.1574 gram H,0.

c,l. 0.2379 gram substance gave 0.4750 gram CO^, and
0.1788 gram H^O.

c,\\. 0.2056 gram substance gave 0.4085 gram COj, and
0.1515 gram H,0.

aj.

b,\.

6,11.

c,l.

<r,II.

c

H

52.63
8.02

52.81
8.09

8.06

54.34
8.36

54.19
8.19

From these five analyses and the preceding ones to which
reference has already been made, it is evident that when
about I atom of sodium is used per molecule of tartaric ester
the resulting product contains about 52.6 per cent of carbon,
and when 2 to 3 atoms of sodium are used the percentage of
carbon is increased to about 54.3. These results show that,
as might be expected, when only i atom of sodium is used,
much diethoxysuccinic ester is formed. Also, that when 2 or
3 atoms are used the product consists mainly of this ester. It
was possible, in some cases, to obtain a product having the
composition of pure diethoxysuccinic ester by fractional dis-
tillation under diminished pressure. As these products did
not have a constant boiling-point it was evident that frac-
tional distillation did not offer a practical method of obtaining
the pure ester or acid.

Action of Ethyl Iodide. 75

According!}', a specimen of ester having the composition of
diethox3'succinic ester and boiling at 127°. 5 to 130° at 9 mm.,
was saponified by warming with a solution of caustic soda in
dilute alcohol. After driving off the alcohol and neutraliz-
ing the excess of caustic alkali, a white crystalline precipitate
was obtained on the addition of barium chloride.

The results of two analyses of this salt were :
I. 0.5035 gram air-dried salt lost 0.0272 gram at 100°.

II. 0.5762 gram air-dried salt lost 0.0313 gram at 100°, and
gave 0.3747 gram BaSO^.

Calculated for Found.

C2H,(0CjH6)2(C03)jBa.H.j0. I. II. III.

H,0 5.01 5.40 5.44 5. II

Ba 38.22 ... 38.27 38.44

The results tabulated under III. were obtained from another
portion of the same sample of ester. In this case, after
saponifying, the solution was acidified and extracted with
ether. The acid, which was a very viscous oil, was dissolved
in water, neutralized with ammonia, and precipitated with
barium chloride.

III. 0.3773 gram air-dried salt lost 0.0193 gram at 100°, and
gave 0.2464 gram BaSO,.

The free acid was prepared from the latter specimen of barium
salt by adding dilute sulphuric acid and extracting with
ether. The ether was removed from the extract at the room
temperature, leaving a very viscous colorless oil. The oil
was soluble in water and gave no color reaction with ferric
chloride solution. On heating a drop of the oil on a watch-
glass over the water-bath, bubbles were given off and it
turned into a white solid. The white solid was very soluble
in water, and gave an intense red color with ferric chloride
solution. It was oxalacetic acid. This reaction and the
composition of the barium salt led to the conclusion that the
oil was not the symmetrical compound, but that it was iden-
tical with the unsymmetrical diethoxysuccinic acid studied by
Michael and Bucher. This was confirmed by dissolving the
oil in water, neutralizing with ammonia, and making the
salts of silver, calcium, and lead by precipitation.

The silver salt, which was a white crystalline precipitate,

76 Bucher.

was dried in the air to constant weight and analyzed with the
following result :

0.6499 gram salt gave 0.4428 gram AgCl.

Calculated for
C2H5(OCjH5)2(C05Ag)2. Found.

Ag 51.40 51-29

The calcium salt separated as a white crystalline precipi-
tate. These microscopic crystals were six-sided pl?tes, many
having four sides curved, so that they had the same appear-
ance as sections cut from a barrel parallel to its axis. The
salt also showed great creeping power when freshly precipita-
ted. These properties are very characteristic of the calcium
salt of unsymmetrical diethoxysuccinic acid. An analysis of
the air-dried calcium salt gave the following result :

0.4963 gram salt gave 0.2553 gram CaSO^.

Calculated for
CHa(OC5H6)2(COj)2Ca.HjO. Found.

Ca 15-28 15.14

The lead salt also was a white crystalline precipitate. The
analysis of the air-dried salt gave the following result :
I. 0.5018 gram salt gave 0.3553 gram PbSO,.
II. 0.5262 gram salt gave 0.3729 gram PbSO,.

Calculated for

Fou

md.

C,H5(0C,H6)2(CO5)jPb.H2O.

I.

II.

48.23

48.35

48.40

Pb

The properties of the free acid and the composition of these
four salts leave no doubt that the acid has the constitution

C(OC,HJ,CO,H

I
CH,CO,H

This complicated the matter somewhat, and in order to ob-
tain a large quantity of ester all the remaining specimens of
the older preparations were united. The 90 grams thus ob-
tained were subjected to fractional distillation. The main
lot boiled at i38°-i43° at 13 mm., about 16 cc. being rejected
at the beginning and 6 cc. at the end of the distillation. This
fraction was again distilled at i33°-i37° at 11 mm., about 3
cc. being rejected at each end. This was redistilled, and the
first two-thirds, boiling at i33°-i35°.5 at 11 mm., was collected

Action of Ethyl Iodide. 77

as fraction ^. [a']D at 23° was -|-i°.4 for this fraction. All
the other fractions were reunited and found to boil at 133°-
139° at II mm. This will be called fraction n. \oc\-a at 23°
was 4" 2°. 5 for this fraction.

The average of three analyses of fraction k and four of frac-
tion n gave the following result :

Calculated for Found.

C.,H,(OC.,H5),(CO,C2H6)j. k n

C 54.89 54-72 53-92

H 8.40 8.22 8.07

Fraction k had the composition of a nearly pure diethoxy-
succinic ester. Exactly 5 grams were saponified by caustic
soda dissolved in dilute alcohol. After the alcohol had been
driven off on the water-bath the excess of alkali was neu-
tralized and an aqueous solution of 5.5 grams of calcium chlo-
ride added. The volume of the solution was 150 cc, and,
after filtering, the precipitate was washed with 150 cc. of
water. The yield of air-dried salt was 2.51 grams, but on con-
centrating the filtrate and washings an additional 0.2 gram
was obtained. This total of 2.71 grams of calcium salt corre-
sponds to 54 per cent of unsymmetrical ester in fraction k.
The salt was not quite pure, however, as it contained 15.98
per cent of calcium. Probably 45 per cent of the unsym-
metrical ester is near the truth. This calcium salt, combined
with that obtained by saponifying the remainder of fraction
k, was acidified with dilute acid and extracted with ether.
The colorless viscous oil thus obtained yielded the pure cal-
cium salt, an analysis giving 15.33 P^r cent of calcium.

Fraction n was treated exactly as fraction k had been.
From 5 grams of ester 1.77 grams of air-dried calcium salt, cor-
responding to 35 per cent of unsymmetrical ester, were ob-
tained. This calcium salt seemed not to be quite as pure as
that from fraction k, and probably 25 per cent is about the
quantity of unsymmetrical ester present. The remainder of
fraction n was saponified and treated with calcium chloride as
before . After filtering off the insoluble calcium salts the filtrate
was acidifi^ed and extracted with ether. On evaporation, a
very viscous colorless oil was obtained, which did not give
any color with ferric chloride solution, before or after it had

78 Bucher.

been heated to 100°. It did not solidify on standing over sul-
phuric acid in the ice- chest for a week. After neutralizing,
it did not give a precipitate vi'ith barium, calcium, or lead
salts. Both the neutral and acid potassium salts are very-
soluble in water. [«']d for this crude acid in aqueous solu-
tion at 18° was +2°. The oil was neutralized with caustic
potash and the solution evaporated to a doughy mass on the
water-bath. Absolute alcohol was then added slowly. In
this way it was possible to separate out a nice crystalline pre-
cipitate. This salt, dried at 150°, gave the following result
on analysis :

I. 0.3244 gram salt gave 0.2010 gram K^SO^.

Another specimen was prepared in the same way, dried at
150°, and analyzed with the following result :

II. 0.4172 gram salt gave 0.2573 gram K^SO,.

Calculated for Found.

C2Hj(OC2H.02(COjK)j. I. II.

K 27.71 27.81 27.68

An aqueous solution of this salt had no action on polarized
light. The pure acid was prepared from this potassium salt
by acidifying and extracting with ether. On evaporating the
ether in vacuo the acid separated as an oil, which quickly
solidified at the temperature of the room. Without further
purification it was dried over sulphuric acid in a partial
vacuum for a week. It melted at ()f~^(f. The results of an
analysis were as follows :

0.2273 gram substance gave 0.3890 gram CO,, and 0.1416
gram H.^0.

Calculated for
C2H2(OC3H6)3(C0.2H)2. Found.

C 46.67 46.58

H 6.92 6.87

The aqueous solution of the acid had no effect on polarized
light. When neutralized with ammonia, it did not give pre-
cipitates with solutions of lead, calcium, or barium salts of
the ordinary strength. It was not changed on heating to
100°. A portion was boiled with 10 per cent sulphuric acid
with reflux condenser, and on adding a solution of phenylhy-
drazin sulphate, no precipitate was formed. This shows

Action of Ethyl Iodide. 79

that no pyruvic acid was formed. These two experiments
show how the above acid differs from the unsymmetrical one,
and it evidently has the constitution represented by the for-
mula

CH(OC„HJCO,H
I

CH(0C,HJC0,H

The remainder of this acid was boiled with water and
barium carbonate. The solution was filtered and evaporated
on the water-bath. The salt which crystallized out was air-
dried, and, on analysis, gave the following result :

0.5025 gram salt lost on heating one hour and a half,
finally at i9o°-2i5°, 0.0872 gram, and gave 0.2836 gram
BaSO,,

Calculated for
C,H2(OC2H5)j(C05)jBa.4H20. • Found.

Ba 33.23 33.22

H,0 17.48 17.35

This salt was soluble in about 12 parts of water at the room
temperature and had no effect on polarized light. Nothing
else was separated in the pure form from these 90 grams of
ester, although there must have been a number of other com-
pounds present. It was at this point that the preparations
already referred to as a, b, and c were made.

Fifteen grams of preparation b were saponified with caustic
soda in dilute alcoholic solution. After driving off the alcohol
on the water-bath, and neutralizing the excess of alkali,
calcium chloride solution was added. Only 50 milligrams of
precipitate were obtained, and this was not the calcium salt
of unsymmetrical diethoxysuccinic acid. Hence, very little,
if any, of the unsymmetrical ester is formed when i atom of
sodium is used per molecule of tartaric ester. This result is
confirmed below under the saponification of fraction a. The
filtrate from the above calcium salt was acidified with sul-
phuric acid and extracted ten times with ether. The first
four of these extracts were united and yielded 5.4 grams of
a very viscous oil, and the remaining six yielded 2.6 grams
more. Neither specimen gave, before or after heating to
100°, a color reaction with ferric chloride, nor did they solidify
in the ice-chest.

So Bucher.

The specimen weighing 5.4 grams was converted into the
barium salt by means of barium carbonate. The solution was
filtered and evaporated to 14 cc. The salt which crystallized
out on cooling was air-dried. The following results were ob-
tained on analysis :

I. 0.4767 gram salt lost, on heating to iio°-i30° for one
hour, 0.0840 gram, and gave 0.2694 gram BaSO^.

II. 0.4026 gram salt lost, on heating to 155° for one hour,
0.0725 gram, and gave 0.2277 gram BaSO^.

Calculated for
C2H2(0C2H5)o(C02)2Ba.4H20.

I.

Found.

II.

Ba 33.23
H,0 17.48

33-26
17.62

33.29
18.01

[«]i5 for this sample in aqueous solution was +I4''- The
salt was recrystallized from water by evaporating in vacuo
over sulphuric acid. The crystals which first separated were
short and compact, looking exactly like those which were
prepared by Purdie and Pitkeathly's method for comparison.
L,ater, however, the substance crystallizing out had a differ-
ent appearance. [<^]d for the recrystallized salt was now
-|-i8°. This is lower than the value given by Purdie and
Pitkeathly, showing the difficulty in separating the active
from the inactive salt. There is no doubt that the part first
separating out is the barium salt of af-diethoxysuccinic acid.
The salts, which remained in the mother-liquor from the first
crystallization of the barium salt, were much more soluble and
less active than the latter. The efforts to isolate them were
entirely unsuccessful.

The 2.6 grams of acid from the last six extractions were
dissolved in a very small quantity of water, and a concentra-
ted solution of lead acetate added. The white precipitate
thus prepared was dried at 100° and gave the following result
on analysis :

0.4828 gram salt gave 0.3823 gram PbSO^.

Calculated for
CjH20H(0CjH5)(C0s)2Pb. Found.

Pb 54.03 54.07

The salt does not separate out unless the solution is rather
concentrated, and it was not examined in polarized light.

Action of Ethyl Iodide. 8i

The existence of the hydroxyethoxysuccinic ester and acid
was confirmed by the next experiment.

Preparation a was saponified in the same manner as the
above. As in the former case, there was little or no precipi-
tate of insoluble calcium salt, proving the absence of the un-
symmetrical ester. The acid was converted into the barium
salt in the usual manner. The solution was then evaporated
on the water-bath until a scum began to form. Absolute
alcohol was added to the hot mass and the pasty precipitate
rejected. The filtrate was treated in the same manner. This
last filtrate was concentrated, acidified, and extracted with
ether. The acid thus obtained was added to a strong solution
of lead acetate, and the white precipitate thus obtained, after
being dried to a constant weight in the air-bath, contained
53-9 P^r cent of lead. This corresponds to the percentage of
lead in the lead salt of hydroxyethoxysuccinic acid.

Preparation c (from 3 atoms of sodium per molecule of tar-
taric ester) was lost, but not before it was shown to contain
much unsymmetrical diethoxysuccinic ester. One gram was
saponified in the usual manner. From this an insoluble cal-
cium salt separated in abundance. The acid prepared from
this showed the characteristic conduct of the unsymmetrical
acid on heating to 100°, and toward ferric chloride solution
before and after heating.

It is evident from the fact that the unsymmetrical diethoxy
ester was formed from tartaric ester, a compound having the
symmetrical constitution, that the reaction must be more com-
plicated than the simple replacement of hydrogen by ethyl.
The following preliminary experiment may throw some light
on the subject : When i molecule of tartaric ester is boiled
with 2 atoms of sodium, dissolved in absolute alcohol, a yel-
lowish-brown salt begins to separate in about fifteen minutes,
and the reaction seems to be complete within an hour. The
salt can be filtered off, and on evaporating the filtrate there
seems to be nothing left except a small quantity of the same
substance.

The salt can be acidified and extracted with ether. The
very viscous oil is apparently a ketone ester, as it gives a
deep-red color with ferric chloride and reacts with

82 Bucher.

phenylhydrazine. On neutralizing the aqueous solution
which had been extracted with ether, and adding calcium
chloride solution, a small quantity of a white precipitate was
obtained. It was the calcium salt of tartaric acid or its iso-
mers.

The yellowish-brown salt, when boiled with caustic soda
and evaporated to a small bulk, yields sodium oxalate very
abundantly. Also, when it is dissolved in dilut.: sulphuric
acid, and a solution of phenylhydrazine sulphate added, a
large quantity of oily product is formed immediately. This
turns to a sticky solid mass in the ice-chest. When this sub-
stance is boiled with caustic alkali it passes into solution.
From this highly colored solution acids precipitate a substance
which it is difl&cult to obtain pure. By alternately boiling
with bone-black and crystallizing from dilute alcohol it was
obtained nearly colorless. With ferric chloride it gave
the violet color-test for i-phenyl-5-pyrazolon-3-carboxylic
acid. The melting-point also corresponded to that of this
compound, but the crystals had a different appearance from
those prepared by other methods. The percentage of carbon
was about 0.5 higher than the calculated amount. It was
probably impure i-phenyl-5-pyrazolon-3-carboxylic acid, but
this conclusion can only be regarded as tentative. If oxal-
acetic ester is formed, this might possibly form an ethoxy
ester by the action of ethyl iodide on its sodium salt, and this,
by the addition of sodium ethylate, form an unsymmetrical
product. W. Wislicenus got a carbon homologue .from the
sodium salt of oxalacetic acid, but he did not follow the reac.
tion very far.

One experiment has been made, using ethyl bromide in-
stead of ethyl iodide with the sodium ethylate and tartaric
ester. The yield of ester was fully as good as with ethyl
iodide, and it has the great advantage of not forming halogen
by-products.

Rhode Island Agricultural College,
Kingston, R. I.

NOTE.

Improvements in the Manufacture of Sulphuric Acid.

In a recent number of the Journal of the Society of Chemi-
cal Industry, there is an interesting address by Professor G.
Lunge from which the following is taken :

" We naturally begin with sulphuric acid, and here we are
at once confronted with the greatest revolution which has
taken place since that acid became a commercial product in
the days of Ward and Roebuck ; a revolution beside which
the invention of the Gay-Lussac and Glover tower, let alone
that of plate-columns and the like, sinks into insignificance.
I mean, of course, the total abolition of the vitriol chamber,
and even of the use of nitrous fumes as oxygen carriers, b)^
the use of the catalytic power of platinum, perhaps also by
that of ferric oxide and other substances, a reaction of which
the first literary landmark is the British patent of Phillips
taken out in 1831, but which has been mainly worked out by
German chemists, Dobereiner, Magnus, Wohler, Plattner,
Clemens Winkler, and others, not to forget my originally
German countryman, Messel. All of these had been content
to apply that reaction to the preparation of sulphur trioxide,
in the shape of Nordhausen fuming acid. Some years ago it
was whispered that the Badische Anilin and Soda Fabrik had
perfected and cheapened that process to such a degree
that they were manufacturing ordinary sulphuric acid in this
way cheaper than by the old process, and thatthey were gradu-
ally pulling down their vitriol chambers. This was hardly be-
lieved to be possible, and was taken as an exaggeration of the
truth. But last year the Badische applied for patents in all
countries, some of which are now published. Other firms
have proceeded on the same lines partly with other contact
substances, among them oxide of iron in the shape of pj^rites
cinders, with which I mj-self experimented many years ago
as a means for combining SO^ with oxygen."

"We now know the Badische invention. The principal
feature of it is their discovery that it is necessary to get rid of
the heat of the reaction in order to obtain a quantitative union
of sulphur dioxide and ox)'gen to sulphur trioxide, and that
under such circumstances a complete union is obtained, even
when using ordinar}^ dilute technical gases, such as result
from pyrites burners. As a measure of the progress made, I
may remind 3'ou that, as I wrote at the end of the year 1897
in ' The Mineral Industry of the United States and Other
Countries,' p. 130 : —

84 Note.

" 'Probably 67 per cent must be considered very good work,
and the remaining 33 per cent, of sulphurous acid must be
sent into lead chambers, together with better gas from other
burners.'

" In lieu of 67 per cent, we must nozv speak of 98 per cent.

" The said removal of the heat of reaction can be effected

in such a way as to heat the entering gases to the temperature

necessary for the reaction, so that the contact stoves when

once started work automatically.

"A further important feature of the Badische invention
consists in the discovery of the reason why the contact-sub-
stance (platinized asbestos) as hitherto used, in a short time
wholly or partly loses its activity, and of means for preventing
this. The cause of this loss of activity has been traced to cer-
tain constituents in the technical gases, the deleterious action
of which was hitherto unknown. To remove these, a special
washing process has been invented, which, in a certain direc-
tion, goes far beyond any attempt at purification published up
to this time.

" Of course there is still a wide step from knowing those
principles, to carrying them out as paying concerns ; although
former employees have offered their knowledge of the princi-
ples referred to for sale for several years, it is not known that
anyone has successfully manufactured from their information.
But it is absolutely certain that at Ludwigshafen itself that
step has been made, and that in more than one large works
the lead chambers are either entirely abolished or at least
moribund.

' ' This is a sad outlook for those whose capital is, to a great
extent, sunk in the old vitriol process! But as yet very many
of them need not despair. It would appear that in the case of
less concentrated acids, up to the point of chamber acid, or
even Glover tower acid, the chamber process can still compete
with the catalytic process, and for acid of such strength there
would be no need whatever to incur the expense of introdu-
cing the catalytic system. Indeed the Badische patents
state : —

' ' 'Acids weaker than up to 50° Be. (that is, containing about 63
per cent H^SOJ can, according to this invention, be pre-
pared at least as cheaply as by means of the chamber process,
and all stronger acids are produced by this invention more
cheaply, the advantages being greater the stronger the acid.'
" In cases, however, where the purity of the acid is an im-
portant point, the Badische process is advantageous even for
dilute acids, for all the acids made by this process are excep-
tionally pure and especially free from arsenic. It is worth

Note. 85

mentioning also that the cost of plant for the new process is
considerably less than that of the old one and requires less
space. Thus, in the Badische works, I am told that the
capital outlay for a plant which is used for making all grades
of acid from anhydride down to weak acid costs about two-
thirds as much as a plant calculated to yield a corresponding
quantity of concentrated oil of vitriol of 66° Be.

" Since in the case of less concentrated acids, say up to
about 80 per cent. H^SO^, the chamber process can still com-
pete for cheapness with the catalytic process, the enormous
capital sunk in vitriol chambers for the manufacture of super-
phosphates, of salt-cake and all analogous cases would still
remain operative ; but certainly vitriol makers are now put
upon their mettle to look out for the best means for improving
the efficiency of their plant and of their method of working.
For various reasons I shall abstain from going into reasons
on that point ; but I may be excused for indulging in some
" music of the future," in mentioning the advantages to be
derived from using oxygen in a more concentrated form than
that of atmospheric air. The proposal of Messel for employ-
ing electrolytic oxygen, or that of myself for Brin's oxygen,
came undoubtedly too early even for the manufacture of SO,
at its former prices, but since we can make a gaseous mixture
rich in oxygen, very cheaply by liquefying air, the possibility
of employing that mixture in the manufacture of sulphuric
acid is decidedly less removed from the sphere of actuality.
In Germany ' lyinde-Iyuft,' as it is there called, is already an
article of commerce ; it is actually used for the preparation of
an explosive, and it is at least thought of even for such uses
as the working of gas-producers. In America they are going
ahead with it much faster, if we may credit even a portion of
the sensational accounts which reach us. Do not let us forget
that in this case the advantage will again lie with those na-
tions who possess cheap force in the shape of water-power, in
order to produce liquid air.

' ' Coming back from the aerial regions to the solid ground
of present facts, there seems to be no doubt that the catalytic
processes have a decided advantage over the chamber process
where acid of a higher concentration than Glover acid or of
special purity is required.

" Proof of this is the fact that one after the other the great
German colour works, where mainly strong acid is used, have
introduced the new processes, or are making preparations for
doing so. But even here some comfort remains to the owners
of lead chambers, and glass or platinum retorts and the like.
Where the initial cost of plant has been written off to a great

86 . Reviews.

extent during former better years, and especially in small-
sized works they will, in the face of the cost of new plant and
of the royalties to be paid for the processes, be able to hold on
to their existing plant for a number of years. The first to
change will be probably those works where much waste acid
is to be disposed of and reconcentrated, as for instance in the
manufacture of explosives. But I must content myself with
these general allusions."

REVIEWS.

The Soi,uble Ferments and Fermentation. By J. Reynolds
Green, Sc.D., F.R.S., Trinity College, Cambridge ; Professor of
Botany to the Pharmaceutical Society of Great Britain ; For-
merly Senior Demonstrator in Physiology in the University of
Cambridge. Cambridge University Press. 1899. 480 pp.

This book, which is one of the Cambridge Natural Science
Manuals, Biological Series, aims to give a full and concise
account of the present state of our knowledge concerning the
so-called soluble ferments. The subject is treated historically
so that we have, in addition, a more or less complete account
of the lines along which development has taken place up to
the present time. This gives the volume added value as a
book of reference, a value which is increased by the very
full bibliography at the end of the volume.

The first chapter deals with the nature of fermentation and
its relation to enzymes, followed by a classification of enzymes,
in which the latter are grouped according to the materials on
which they work. While the list is not wholly complete,
mention is made of urease which forms ammonium carbon-
ate from urea, and the new zymase of Buchner, i.e., the alco-
hol-producing enzyme. Four chapters are devoted to a dis-
cussion of vegetable and animal diastase, while inulase, cytase
and other cellulose-dissolving enzymes, urease, pectase, oxida-
ses or oxidizing enzymes, are each given a chapter descriptive
of their chemico-physiological properties. To proteolytic en-
zymes and proteolysis three chapters are devoted. The clot-
ting enzymes are likewise given due consideration, while fat-
splitting enzymes and sugar-splitting enzymes are duly con-
sidered, as are also alcoholic fermentation, the fermentative
power of protoplasm, the secretion of enzymes, the constitution
of enzymes, while a brief account of the theories of fermenta-
tion closes the volume.

We have in this book by Dr. Green, a very readable state-
ment of existing knowledge regarding enzymes, but we fail
to find in it much that is original. This, perhaps, is hardly

Reviews. 87

to be expected, since the book aims primarily, as stated in
the preface, "to put together as far as possible, the results
reached up to the present time." The book is especially op-
portune at the present moment, since we have now reached a
point in our knowledge where we are practically compelled to
drop the old distinction between organized and unorganized
ferments, and the more thoroughly knowledge is disseminated
regarding the part which enzymes play in intracellular, metab-
olism, so much the sooner will the chemical and physiologi-
cal world acquire a true appreciation of the many points of
similarity between the metabolic processes of higher and lower
organisms. Enzymes are unquestionably intimately associa-
ted with the living substance of protoplasm, and consequently
we may look for an intimate relationship between fermentation
and the ordinary processes of metabolism. For furthering
the spread of knowledge regarding these points, the present
volume is especially well adapted, and the book is to be wel-
comed as a valuable addition to the store-house of knowledge.
Careful scrutiny of the subject-matter composing some of
the chapters of the book must lead to criticism of the
thoroughness with which the work of compilation and selection
has been done. Thus, on pages 264-267, dealing with the
myosin ferment and the proteids of muscle, we look in vain for
any reference to the very important work of Von Furth on this
subject, which appeared in volumes 36 and 37 of the Archiv
fur experitne^itelle Pathologie und Pharmakologie, 1895-1896.
Further, in chapter XVI, dealing with thrombase, the fibrin-
ferment, we find among the various facts and theories of
blood-coagulation discussed, no mention of the widely quoted
work of Ivilienfeld on this subject, which appeared in 1894,
and which is now incorporated in all recent text-books of phys-
iological chemistry. Again, on page 188, where the character-
istic products of trypsin-proteolysis are discussed, we look in
vain for any mention of the very important work of Kossel
and his coworkers on the hexone bases, arginin, lysin, and
histidin, which are now recognized as among the characteris-
tic end-products of trypsin-proteolysis. Among these bases,
lysin was first emphasized as a product of trypsin-proteolysis
in 1 89 1 by Drechsel and Hedin. These are a t3'pe of criti-
cisms, however, which apply to nearh^ all books. Perfection
is not of this world. It may be, however, that these omissions
simply represent the author's opinion of the relative value of
the omitted facts as contrasted with those presented. If this
is the case, the reviewer cannot agree with the author in his
estimate of their relative value in any discussion of soluble
ferments and fermentation.

R. H. Chittenden.

88 Reviews.

EiNFUHRUNG IN DIE ChEMIE IN LEICHTFASSLICHER FORM. VON

Prof. Dr. Lassar-Cohn. Konigsberg, Hamburg und Leipzig;
Verlag von Leopold Voss.

In this volume Prof. Lassar-Cohn offers a text-book of
chemistry for university-extension work. He acknowledges
in his preface that the problem of how to write a book for
this purpose is difficult, and that the task first seemed to him
impossible. The present volume is a natural sequence of his
popular lectures published under the title " Die Chemie im
taglichen Leben,'" and every reader of those admirable lec-
tures will feel that lyassar-Cohn was well qualified to attempt
a text-book simpler in form and matter than those used in col-
leges, yet addressed to thinking men and women.

The descriptive part of the book treats of the more impor-
tant elements and inorganic compounds, omitting all reference
to less important substances ; the theoretical part covers the
same field as an ordinary text-book of inorganic chemistry.
In the chapter on carbon, the commonest organic compounds
and their relations to the simpler hydrocarbons are briefly
discussed, while the fundamental theories of organic chemistry
including substitution, valence, Kekule's benzene theory,
isomerism, ortho, meta, and para compounds, are explained
clearly and simply.

The impression left on the reviewer is that the author has
succeeded in his task ; that he has written a book simple
enough to enable an intelligent working man to master it
with the help of experimental lectures, and scientific enough
to give the learner a solid basis for further work, should op-
portunity offer. The book should interest us all in view of
the spread of the university-extension movement in this
country. E. R.

iThe English translation of this book by M. M. Pattison Muir, "Chemistry in Daily
Life" was reviewed in This Journal, 19, page 81.

Vol,. XXIII. February, 1900. No. 2.

AMERICAN

Chemical Journal

ON SOME ABNORMAIv FREEZING-POINT LOWER-

INGS PRODUCED BY CHI.ORIDES AND

BROMIDES OF THE ALKALINE

EARTHS.

By Harry C. Jones and Victor J. Chambers.

Jones and Mackay,' in their work on solutions of double
sulphates, used both the conductivity and freezing-point
methods to determine the condition of these substances in
solution. Jones and Ota,^ in their work on the double chlo-
rides, attempted to follow the same plan. They succeeded in
applying the conductivity method to the solutions of double
chlorides and their constituents, but were not able to get satis-
factory results with the freezing-point method. The results
were irregular in the case of the double salts, and did not point
to any definite conclusion. Jones and Knight^ extended the
work of Jones and Ota to a number of double chlorides and
bromides, and again attempted to apply the freezing-point
method in the same connection. They also obtained unsatis-
factory results in the cases of a number of double salts, and
found, for some of the constituents, that the molecular lower-

1 This Journal, 19, 83.

2 Ibid., 22, 5.

3 Ibid., 22, no.

go Jo7ies ayid Chambers.

ing increased with increase in concentration from a certain
dilution, and then increased again from this point with the
dilution, as would be expected. The increase in the molecu-
lar lowering became very marked at great concentrations, in-
deed, so pronounced that the molecular lowering of a normal
solution was as great as, or greater than, the theoretical molec-
ular lowering when all of the salt was completely dissociated.

This was evidently a phenomenon worthy of careful study,
and we undertook the investigation which will now be de-
scribed. Before beginning experimental work we examined
the literature to ascertain what had been done bearing upon
this point.

Arrhenius,' in applying the freezing-point method to the
then newly proposed theory of electrolytic dissociation, found
the following freezing-point lowerings for a few solutions of
calcium, strontium and magnesium chloride, and cadmium
iodide :

CaCl,.
Concen- Molec.
tration. low.

SrCl,.
Concen- Molec.
tration. low.

MgCl,.
Concen- Molec.
tration. low.

Cdl,.
Concen- Molec.
tration. low.

0.0476 5.17

0.043

5-37

0.0532

5-13

0.0544 2.96

O.II9 4.95

0.107

4.89

0.133

5.02

0.136 2.35

0.199 5-OI

0.214

4.92

0.322

5.33

0.342 2.09

0.331 5-i6

0.356

5-03

0.537

5.70

0.684 2.19

In each of these cases the molecular lowering increases with
the concentration, from a certain point, and then increases
from this same point with the dilution. The data are, how-
ever, too meager to warrant conclusions to be drawn from
them. Further, when this work was done the freezing-point
method was so imperfectly developed, that errors of consider-
able magnitude are necessarily present in the results.

From the work of Arrhenius, it seems probable that a min-
imum in the freezing-point lowering exists in a few other salts.

An increase in the molecular lowering with increase in con-
centration was also observed by Arrhenius'^ in the cases of
four organic compounds, glycerin, mannite, dextrose, and
cane-sugar. This has been subsequently^ verified by one of
us' for cane-sugar and dextrose.

1 Ztschr. phys. Chem., 2, 496.

2 Ibid., 3, 495-

^.^3 Jones : Ibid., 12, 642.

Abnormal Freezing -poi7it Lowerings. 91

A possible explanation of the increase in molecular lower-
ing, from a certain point, with increase in concentration, has
been offered by Arrhenius' for the non-electrolytes.

In the formula for osmotic pressure :
;r= AK+ BK'.

n is the osmotic pressure, A is the product of the gas con-
stant R into the absolute temperature, B is a new constant,
which gives the difference between the following attractive
forces : That between the solvent and dissolved substance,
and that of dissolved substance for itself. K is the concen-
tration.

If the concentration K is small, BK* with respect to AK is
small, and we have the law for an ideal gas. But if K in-
creases, the osmotic pressure would, relatively, increase or de-
crease as B is positive or negative. But with water as a sol-
vent, B is, in general, positive. Therefore, as solutions which
fulfil the above conditions increase in concentration, the
osmotic pressure would increase more rapidly than the con-

centration, and -=p- would increase.

He showed later, in the same communication, that propor-
tionality exists between osmotic pressure and freezing-point
lowering. Since freezing-point lowering is proportional to

E

osmotic pressure, -T^ would increase (^r:= lowering), and this

agrees with experimental facts.

An increase in the molecular lowering of the freezing-point,
with increase in concentration, has been observed by Loomis^
for hydrochloric acid and magnesium chloride. He obtained
the following results :

Hydrochloric acid. Magnesium chloride.

Concentration. Molec. low. Concentration. RIolec. low.

O.OI

3.61

O.OI

5-14

0.02

3.60

0.02

5-07

0.05

3-59

0.05

4-98

O.IO

3-546

O.IO

4.948

0.20

3-565

0.15

4-965

0.30

3.612

0.20

5-OI9

0.25

5-079

0.30

5-186

:hr. phys. Chem., lo, 51.

2 Wied., Ann., 57, 503.

92 Jones ayid Chambers.

lyoomis did not obtain any evidence of a minimum of
molecular lowering with barium chloride. He concluded
from his extensive work on freezing-point lowerings, that
" the molecular lowering continually increases with the dilu-
tion. The only exceptions are MgCl, and HCl in the region
of stronger concentration. Both show a minimum value of
the molecular lowering at w = o.io (m = concentration nor-
mal). This minimum is pronounced with MgCl^, it is much
less striking with HCl but is just as certain. To avoid any
possible doubt in reference to the minimum with hydrochloric
acid, the value of the molecular lowering for 0.3 normal was
determined. This shows with certainty the position of the
minimum at approximately o.i normal."

The work which has been done hitherto is thus evidently
fragmentary, and shows that for a few substances there is a
minimum of molecular lowering. But no generalization
whatever can be made from what has thus far been done.
Are these abnormal results peculiar to a substance here and
there, regardless of its chemical nature, or are they confined
to some group of compounds ? Do substances which are
chemically allied show this peculiarity, or is it due to some
physical property or properties of the compounds ? It is with
the hope of answering such questions as these that we have
taken up a systematic study of the problem.

It is well known that the alkaline halides give normal
freezing-point lowerings, i. e., the molecular lowering increases
with the dilution from the greatest concentrations which have
been studied. It is also very probable from what has already
been done, that cadmium chloride gives normal lower-
ings of the freezing-point. Since abnormal values had
already been observed by Jones and Knight for one or two
members of the calcium group (the alkaline earths) , we de-
termined to study this group more thoroughly. We have
therefore measured the lowering of the freezing-point of water
produced by calcium chloride, barium chloride, strontium
chloride, and magnesium chloride. In order to see whether
the same abnormal values were obtained with cadmium, we
also measured the freezing-point lowerings of fairly concen-
trated solutions of cadmium chloride.

Abnormal Freezing-point Lowerings. 93

In measuring the freezing-point lowerings produced by the
above compounds, care was taken to keep the temperature of
the freezing-bath only a little below the temperature at which
the solution froze. Indeed, the bath was always kept at the
highest temperature at which it was possible to freeze the solu-
tion. The difference between the temperature of the bath and
that of the solution w^hen it froze was always less than 2°.

A number of experiments were made to determine the
effect of the temperature of the bath on the freezing-point of
the solution. While the molecular lowering of dilute solutions
changed very appreciably with change in the temperature of
the bath, this was not observed with the more concentrated
solutions. A change of 5° or 6° in the temperature of the bath,
changed the molecular lowering of the most concentrated solu-
tions to only a slight extent. This is what we might expect,
since the magnitude of the quantity measured is so much
smaller for the more dilute solutions. The apparatus used
was essentially that described by Beckmann, with some slight
changes.

The results which we obtained for the chlorides named
above, are given in the following tables. The most concen-
trated solution of each chloride was standardized gravimetric-
ally by determining one of the constituents. From this, all of
the remaining dilutions were prepared. Column I gives the
concentration of the solution in terms of normal, column II
the observed lowering of the freezing-point, column III the
correction for ice separation, column IV the correct lowering
of the freezing-point, and column V the molecular lowering.

Calcium

Chloride

{iio.g).

I.

II.

III.

IV.

v.

0.102

0.519°

o.oii''

0.508°

4-98

0.153

0.770

0.018

0.752

4

91

0.204

1.045

0.033

1. 012

4

96

0.255

1.294

0.027

1.267

4

97

0.306

1-577

0.040

1-537

5

02

0.408

2.124

0.020

2.104

5

16

0.510

2.724

0.043

2.681

5

26

0.612

3-397

0.049

3-348

5

47

94 Jones and Chambers.

Strontium Chloride {138.6).

I.

II.

III.

IV.

V,

0.05

0.265°

0.007°

0.258°

5-16

O.IO

0.501

0.013

0.488

4.88

0.135

0.673

0.021

0.652

4.82

0.20

1.002

0.029

0.973

4-87

0.30

1.498

0.027

1. 471

4-90

0.40

2.007

0.029

1.978

4.95

0.50

2.597

0.053

2.544

5.09

0-75

4.166

0.095

4.071

5-42

Barium Chloride {208. j).

I.

II.

III.

IV.

V.

0.0976

0.480°

0.007°

0.473°

4-85

0-I953

0.959

0.027

0.932

4.77

0.2929

1.448

0.035

1.413

4.82

0.4882

2.485

0.067

2.418

4-95

0.5858

3-005

0.060

2.945

5-03

Magnesium Chloride {93.26).

I.

II.

III.

IV.

V.

0.0508

0.287°

0.007°

0.280°

5-51

0.1016

0.550

0.013

0.537

5-28

0.1525

0.798

0.027

0.771

5-06

0.2033

1.088

0.030

1.058

5.20

0.2541

1.372

0.037

1-335

5-25

0.3801

2.055

0.040

2.015

5-30

0.5082

2.837

0.075

2.762

5-43

0.6099

3-5IO

0.038

3-472

5-69

Cadmium, Chloride

{182.9).

I.

II.

III.

IV.

V.

0.214

0.743°

0.016°

0.727°

3-39

0.322

1. 051

0.029

1.022

3-18

0.429

1.342

0.044

1.298

3-03

0.643

1.862

0.030

1.832

2.85

0.858

2.369

0.040

2.329

2.72

1.072

2.908

0.023

2.947

2.65

It will be seen from the above results that the chlorides of
calcium, barium, strontium, and magnesium, all have a mini-
mum lowering which lies between o.i and 0.2 normal. The
results for cadmium chloride show that the molecular lower-

Abnormal Freezing-point Lowerings. 95

ing increases from the most concentrated to the most dilute
solution used, there being nothing to indicate the presence of
a minimum in the molecular lowering.

The relations between the molecular lowerings for the
above substances will be seen most readily in the following
curves (Fig. I). The molecular lowerings are plotted as
ordinates, the concentrations as abscissae.

The dotted portions of the curves, and the entire curve for
sodium chloride introduced for the sake of comparison, are
plotted from data previously obtained by one of us.'

Having found this minimum in the molecular lowering for the
chlorides of the alkaline earths, we next turned our attention
to the bromides of this group. These compounds, like the cor-
responding chlorides, were carefully purified, and a standard
solution prepared in each case. From this solution all the
remaining dilutions were made. The bromides of calcium,
barium, strontium, and magnesium were studied to ascertain
whether there is a minimum in the molecular lowering,
and if so, at what concentration it exist. The bromide of
cadmium was examined to see whether it is normal, like
cadmium chloride. It is well known that the bromides of the
alkalies behave normally, /. <?., the molecular lowering in-
creases throughout with increase in dilution. The results
which were obtained for the bromides are given in the follow-
ing tables, the several columns representing the same quan-
tities as with the corresponding chlorides :

Calcium Bromide {igg.g2).

I. II. III. IV. V.

0.04355 0.233° 0.005° 0.228° 5.24

0.08710 0.462 0.017 0.445 5-II

0.13065 0.686 0.022 0.664 5.07

0.17422 0.936 0.032 0.904 5.18

0.2613 1-403 0.035 1-368 5.23

0.3484 1.893 0.046 1.847 5.30

0.4355 2.421 0.024 2.397 5.50

0.5226 3.007 0.058 2.949 5.64

1 Jones ; Ztschr. phys. Chem., ll, 113, 529.

ng.r

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Abnormal Freezing-point Lowering s.

97

Strontium Bromide

{247-59) •

I.

II.

III.

IV.

V.

0.052

0.270°

0.008°

0.262°

5-04

0.103

0.521

0.018

0.503

4

88

0.155

0.795

0.022

0.773

4

98

0.207

1.062

0.027

I -035

5

00

0.259

1.327

0.019

1.308

5

05

0.310

1. 615

0.023

1-592

5

13

0.414

2.203

0.056

2.147

5

19

0.517

2.781

0.040

2.741

5

30

0.621

3.516

0.069

3.447

5

55

Barium Bromide (.^p/.j/) .

I.

II.

III.

IV.

V.

O.IO

0.518°

0.012°

0.506°

5.06

0.15

0.759

0.022

0.737

4.91

0.20

1.026

0.025

1. 001

5-00

0.40

2.084

0.045

2.039

5-09

0.50

2.633

0.042

2.591

5.18

Magnesium

Bromide

{I84.2J).

I.

II.

III.

IV.

V.

0.0517

0.283°

0.006°

0.277°

5-36

0,103

0.557

0.026

0.531

5-14

0.155

0.824

0.023

0.801

5-17

0.207

1.093

0.005

1.088

5-26

0.310

1. 710

0.020

1.690

5-45

0.414

2.413

0.066

2-347

5-67

0.517

3-097

0.075

3.022

5-84

Cadmium Bromide

{272.2).

I.

II.

III.

IV.

V.

0.22

0.665°

0.013°

0.652°

2.959

0.44

1.220

0.007

1. 213

2.757

0.66

1.768

0.030

1-738

2.633

0.88

2.314

0.037

2.277

2.

S87

The results obtained for the bromides are plotted in curves
(Fig. II), the same units being used as ordinates and ab-
scissae as in Fig. I. The dotted portion of the curve for cad-
mium bromide was plotted from results previously obtained
by one of us.'

The curves for the bromides as for the chlorides show a

1 Jones : Ztschr. phys. Chetn., 11, 529.

98 Jo7ies and Chambers.

distinct minimum, and all of them at about the same dilution,
from o. I to 0.15 normal. Thisisalmost exactly the same con-
centration as that at which the corresponding chlorides showed
a minimum of molecular lowering. The curves of the chlo-
rides were extended, in a number of cases, be3^ond the dilu-
tion used in this work, on the basis of work previously done,
to show that the minimum of molecular lowering had un-
questionably been reached. The results for sodium chloride
were plotted on the same scale, for the sake of comparison.

The general conclusion which can be drawn from the freez-
ing-point lowerings is that all the chlorides and bromides of
the alkaline earths have a minimum of molecular lowering of
the freezing-point, this minimum lying between o. i and 0.2
normal. Further, in very concentrated solutions these sub-
stances give a lowering of the freezing-point as great as, or
greater than, the theoretical lowering, if the compounds were
completely broken down into ions. These apparently abnor-
mal results are shown neither by the alkaline halides nor by
the halogen compounds of the magnesium-zinc group.

It is a little difl&cult to see at first sight how these results
can be brought into accord with the theory of electrolytic dis-
sociation, or interpreted in terms of it. Before attempting
any explanation of these results, we determined to measure
the conductivity of the same solutions whose freezing-point low-
erings we had studied. The conductivities of a number of
these solutions had already been measured by Jones and
Knight,' in connection with their work on the condition of
double chlorides and bromides in solution. We measured
the conductivities of the more concentrated solutions of cal-
cium and barium chlorides, and calcium, strontium, and
magnesium bromides. For the conductivities of the more
dilute solutions of these substances we are indebted to Mr.
Caldwell, who kindly made the measurements which we de-
sired. The conductivities of the remaining compounds had, as
already stated, been measured by Jones and Knight.

We give below the molecular conductivities of the com-
pounds which showed abnormal freezing-point lowerings, and
state in each case by whom the measurements were made :

1 This Journal, 22, no.

Abnormal Freezing-point Lowering s.
Calcium Chloride. Strontium Chloride.

99

(Chambers.)

(Knight.)

V.

h^v 25°.

V.

l^v 25°.

1. 961

134.3

I

108.5

3.912

152.06

2

130.0

4.902

156.62

4

146.6

6.536

164.75

8

162.6

9.804

174-05

16

179-5

12.256

179-35

40

196. 1

19.610

185-75

80

207.4

33-333

197-50

160

219.0

(Caldwell.)

320

229.3

32.66

198.15

640

237-6

65-33

210.8

1600

246.4

130.66

222.55

3200

252.5

261.33

234-97

6400

260.0

522.66

244.94

12800

270.0

1045-33

246.59

2090.66

253.44

4181.33

265.73

Barium Chloride.

Magnesium, Chloride.

(Chambers.)

(Knight.)

V.

h^v 25°.

V.

}^v 25*.

2.013

131.45

1.76

126.3

4.026

148.37

3-52

143.3

5-033

158.44

7.04

159.8

6. 711

161. 14

14.08

175. 1

10.063

170.62

35.2

190.3

12.580

184.85

70.4

201. 1

20.130

191. 16

140.8

211. 3

33-558

200.88

281.6

221,1

(Caldwell.)

563.2

227.4

33.547

203.06

1408.0

234.5

67.094

213.78

2816.0

243-2

134.188

224.77

5632.0

253-3

268.37

237.0

536.75

248.2

1073.5

260.8

2147.0

270.3

4294.0

276.3

lOO

Jones and Chambers.

Calcium Bromide.

Strontium Bromide.

(Chambers.)

(Chambers.)

V.

l^v 25°.

V.

l^v 25°.

2.193

151.2

1.932

141-33

4.596

170.88

3.864

159-46

5-74

174.37

4.831

165.7

11.48

189.8

6.439

171. 6

M-34

191-9

9.661

18:. 5

22.96

201.3

12.08

183-9

38.27

2IO.I

19.32

194. 1

32.20

207.7

(Caldwell.)

(Caldwell.)

38.27

208.2

32.19

208.6

76.54

219.8

64.38

221.6

153.08

230.3

128.8

231.6

306.2

241.2

257-5

244.6

612.3

248.8

515-0

254.2

1224.7

256.0

1030. 1

261.8

2449.0

262.5

2060.2

272.5

4898.0

270.2

4120.3

282.4

Barium Bromide.

Magnesium

Bromide.

(Knight.)

(Chambers.)

V.

f^v 25°.

V.

f^v 25°.

2

147.7

3.868

141-9

4

162.4

4.812

159-3

8

176.5

6.447

163.8

16

190.9

9.671

173-5

32

202.0

12.09

176.2

80

218.5

19-34

187-5

160

228.8

32.26

190.3

320

241.5

(Caldwell.)

640

249.2

32.24

191. 7

1280

257-1

64.48

206.1

3200

270.8

128.9

216.7

6400

280.8

257-9

226.8

515-8

234.8

1031.6

245.0

2063.2

253-9

4126.3

257.8

For the sake of comparison, the conductivities of cadmium
chloride and cadmium bromide, as measured by Knight, are
also given.

Abnormal Freezing-point Lowerings. loi

Cadmium Chloride. Cadmium Bromide.

(Knight.) (Knight.)

V.

}^v 25°.

V.

}^v 25°.

0.932

28.0

2.60

41-3

1.864

44.9

5.20

57-4

3.728

62.8

10.40

75-7

7-456

82.5

20.80

95-1

14.91

IOI.5

41.60

115-3

• 37-37

129.6

104.0

144.2

74-75

150.3

208.0

166.0

149-5

171. 7

416.0

188.8

299.0

192.3

832.0

209.3

598.0

206.5

1664.0

228.2

1495-0

227.6

3328.0

242.4

2990.0

242.0

6656,0

256.1

5980.0

255-3

1 1960.0

269-5 .

The conductivity measurements given in the above tables
are plotted in curves (Figs. Ill and IV), that they may be
compared directly with the freezing-point lowerings. The
conductivities of the dilute solutions are not included in the
curves, since these are far less interesting from our present
point of view. The conductivity results, from the most con-
centrated solutions used to about 0.025 normal, are included
in the curves. The part of the conductivity curve which is
of special interest is that for the concentration at which the
freezing-point curve shows a minimum. We wish es-
pecially to see whether there is any irregularity in the con-
ductivity curve in this region. The molecular conductivities
are plotted as ordinates, the concentrations as abscissae. The
concentrations are expressed in " volumes," or the number of
liters which contain a gram-molecular weight of the sub-
stance. An examination of the conductivity curves shows no
irregularity in the region where the molecular lowering of
freezing-point becomes a minimum. The conductivity curves
are just such as would be expected for any strongly dissocia-
ted electrolyte in water. The conductivity increases regu-
larly from the most concentrated to the most dilute solution
investigated, and shows a continually increasing dissociation
with increase in dilution.

Ul

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Abnormal Freezing-point Lowerings. 103

A Possible Explanation of the Abyiormal Res7ilts.

The facts which have to be taken into account are these :
The molecular lowering of the freezing-point increases from
about 0.1 normal with increase in concentration and also
with increase in dilution, there being a minimum of molecu-
lar lowering for the chlorides and bromides of the alkaline
earths at about this concentration. The increase in molecu-
lar lowering with increase in dilution is normal, but the in-
crease in the molecular lowering with increase in concentra-
tion is abnormal, and apparently at variance with the theory
of electrolytic dissociation.

The conductivities of solutions of these chlorides and bro-
mides increase, as would be expected, from the most concen-
trated to the most dilute solution employed.

These facts mean that the freezing-point lowering produced
by concentrated solutions of these chlorides and bromides are
much greater than we should expect from a consideration of
the theory, especially when we take into account the fact that
the dissociation of the most concentrated solutions is hardly
more than 50-60 per cent, as is shown by the conductivity
measurements.

How is it then possible to account for these abnormally
great depressions of the freezing-point ? There appears to us
to be only one way. In concentrated solutions these chlo-
rides and bromides must take up a part of the water forming
complex compounds with it, and thus removing it from the
field of action as far as freezing-point lowering is concerned.
The compound, which is probably very unstable, formed by
the union of a molecule of the chloride or bromide with a
large number of molecules of water, acts as a unit, or as one
molecule in lowering the freezing-point of the remaining
water. But the total amount of water present, which is now
acting as solvent, is diminished by the amount taken up by
the chloride or bromide molecules. The lowering of the
freezing-point is thus abnormally great, because a part of the
water is no longer present as solvent, but is in combination
with the chloride or bromide molecules. By assuming that a
molecule of the halide is in combination with a large num-

I04 Jones atid Chambers.

ber of molecules of water, it is possible to explain all of the
freezing-point results obtained.

But the conductivity results must also be taken into ac-
count. These show, unmistakably, a marked degree of dis-
sociation even in the most concentrated solutions employed.
There must, therefore, be a certain number of the molecules
broken down into ions, either by the water acting as solvent,
or by the water in combination with the molecules, just as
salts are probably dissociated in their water of crystallization.

We know of cases where there is direct experimental proof
that molecules combine with water in the more concentrated
solutions, and are then dissociated with increase in dilution.

The case of sulphuric acid is especially interesting in this
connection. It was shown by one of us,' while working in
the laboratory of Arrhenius, that sulphuric acid first forms the
definite hydrates, H,SO,.H,0 and H,S0,.2H,0, and then, on
further addition of large volumes of water, it is known from
the conductivity measurements that sulphuric acid breaks
down completely into ions.

The existence of the hydrates was shown by the freezing-
point method. Acetic acid was used as the solvent, and the
lowering of its freezing-point produced by sulphuric acid
alone was determined. Then the lowering of the freezing-
point of acetic acid by water alone was determined, and,
finally, the lowering produced by sulphuric acid and water
when brought together into the acetic acid. This was never
equal to the sum of the separate lowerings, and from the
amount of the difference the amount of water in combination
with the sulphuric acid was calculated.

It should be observed in connection with the explanation
we have offered of these abnormal results, that the chlorides
and bromides of the alkaline earths are, generally, very
hygroscopic substances, resembling sulphuric acid in their
power of attracting water. Some of them are, it is true, far
more hygroscopic than others, yet, when dehydrated, they all
combine readily with water. It may be due to this property
that they combine with water to such an extent in concentra-
ted solutions. It is true that the chlorides of zinc and cad-

1 Jones : Ztschr. phys. Chem., 13, 419 ; This Journal, 16, i.

Preparatioti of Pure Tellurium. 105

mium are also hygroscopic, but the halides of zinc, and es-
pecially of cadmium and mercury, behave, in general, abnor-
mally with respect to their dissociation in water.

It should also be noted that the compound, in addition to
magnesium chloride, with which I^oomis found a minimum of
molecular lowering — hydrochloric acid — is also very hygro-
scopic, attracting water with great energy.

We do not put forward the above suggestion to account for
our results as a final statement of a theory, but only as tenta-
tive, and subject to modification as new facts are brought to
light. It does, however, seem to account qualitatively for
the experimental facts which have been brought to light.

We propose to extend this investigation to a much larger
number of hygroscopic substances, to ascertain whether there
is any relation between this property and abnormal freezing-
point lowerings such as those recorded in this paper.

Chemical Laboratory,

Johns Hopkins University,

May, 1899.

Contributions from the Chemical Laboratories of the Massachusetts Institute of Tech-
nology.

XXIII.— THE PREPARATION OF PURE TELI.U-

RIUM.

By James F. Norris, Henry Fay, and D. W. Edgerly.

In testing a volumetric method' for the estimation of tellu-
rium which we proposed some time ago, we were led to study
the methods which had been used for the purification of tel-
lurium. As it appeared that a substance of undoubted purity
could be obtained only by a very long series of operations,
which involved fusion with potassium cyanide, precipitation,
and subsequent distillation in hydrogen, a new method was
sought. It seemed probable that the basic nitrate of tellurium
might be used for this purpose, as it is a well-crystallized
compound, very easily obtained. We accordingly prepared
it, and having found that the sample did not agree in some of
its properties with those which had been assigned to it in the
literature, a careful study of it was made. Klein and Morel''

1 This Journal, 20, 278.

2 Bull. See. Chim. [2], 43, 198.

io6 No7-ris, Fay, and Edgerly.

prepared the compound b}^ dissolving tellurium in nitric acid
(1.25 sp. gr.) and evaporating the solution. To the crystals
which formed they assigned the formula 4Te02.N,05.i|H,0.
Only very small crystals were formed and these were hygro-
scopic. The nitrate prepared by us by the method of Klein
and Morel was obtained in crystals sometimes a centimeter in
length and were not hygroscopic. An analysis was accord-
ingly made, which showed that the compound has ^he formula
4TeO,.N,0,.H,0, or better Te,0,(0H)N03, since the wateris
not present as water of crystallization.

In the preparation of the nitrate it is crystallized from nitric
acid, and as the impurities present in the tellurium do not
form crystalline compounds under these conditions, it was
thought that the salt could be obtained quite pure. The tel-
lurium obtained from it would, as a result, be free from those
substances with which it is invariably mixed when precipita-
ted from solution by sulphur dioxide or other reducing agents.
A sample of basic nitrate was recrystallized three times and
then subjected to a careful study, with the result that no im-
purity was discovered.

On account of the fact that the most trustworthy atomic
weight determinations of tellurium have given results which
place it in the eighth group in the periodic system of the ele-
ments, notwithstanding its striking similarity to sulphur and
selenium, the hypothesis has been put forward that tellurium
is a mixture of true tellurium with an atomic weight of about
125, and another element with a higher atomic weight.
Brauner,' who spent a number of years studying tellurium,
has expressed this as his opinion.

As no known substance was found in the tellurium obtained
from the pure nitrate, the element was subjected to a fraction-
ation to determine whether it could be broken down into two
or more substances by this means, which proved so effective
in the case of didymium. The double bromide of tellurium
and potassium, made from tellurium dioxide, hydrobromic
acid, and potassium bromide prepared with the greatest care,
was carried through a fractionation which involved over 200
crystallizations. In order to determine whether this fraction-

1 J. Chem. Soc, 55, 382 ; and 67, 549.

Preparation of Pure Tellurium. 107

ation had accomplished any decomposition, the tellurium from
the end fractions was converted into the nitrate, and the loss
in weight of the latter compound on ignition determined.
Any change in atomic weight could be determined in this
way. The results obtained with the two fractions were iden-
tical within the limits of accuracy of the method. The difier-
ences obtained, 0.4 of a unit in the atomic weight, was proba-
bly due to inaccuracies in the method. The conversion of the
nitrate into the oxide, as at present carried out, does not ap-
pear to give results from which the atomic weight of tellurium
can be determined with great accuracy.

Preparation of Basic Tellurium Nitrate.

The tellurium used was obtained from a residue obtained in
the electrolytic refining of copper. This residue was a solu-
tion which consisted principally of the sodium salts of tellurous,
selenous, and silicic acids, with the last-named acid in great
excess. Whitehead' has described the process by which the cop-
per is refined and how the liquid is obtained. Tellurium was
obtained from this liquid in two ways. At first the solution was
diluted with water and neutralized with sulphuric acid, which
threw out a heavy white precipitate of tellurous acid and
silica. This mixture was evaporated to dryness twice with
hydrochloric acid to render the silica insoluble, and the resi-
due extracted several times with strong hydrochloric acid.
From the solution of the chloride so formed, the tellurium
was obtained by precipitation with acid sodium sulphite. In
later experiments the tellurium was precipitated from the hot
alkaline solution with commercial glucose. The tellurium
obtained by both methods contained silica and other impuri-
ties. The crude metal was added to warm dilute nitric acid
(sp. gr. 1.25), and the resulting solution evaporated to dry-
ness in order to insure complete removal of silica. The mix-
ture of basic nitrate and oxide was ignited till free from nitric
acid, and was then extracted a number of times with strong
hydrochloric acid. The solution in hydrochloric acid was fil-
tered through asbestos and precipitated with acid sodium sul-
phite. The sulphite was added slowly until the precipitate

1 J. Am. Chem. Soc, 17, 849.

io8 Norris, Fay, and Edgerly.

formed was black, thus showing that most of the selenium was
precipitated. After the mixed precipitates of selenium and
tellurium had settled, the solution was decanted, filtered, and
the precipitation continued. The tellurium which had been
freed from a large share of its impurities by this second pre-
cipitation was again dissolved in nitric acid (sp. gr. 1.25), and
the basic nitrate obtained from the solution by crystallization.
The nitrate was twice recrystallized. This was bes', done as
follows : The salt was stirred with a large amount of nitric
acid (sp, gr. 1.25) heated to about 70° C. At a higher tem-
perature the nitrate was decomposed into a mixture of amor-
phous and crystalline oxide, which was not readily dissolved
by the acid. The solution was filtered through asbestos and
evaporated at a temperature of about 80°. In some cases the
solution was allowed to cool after crystals appeared. In other
cases the evaporation was continued while the crystals were
separating from the liquid. By the latter method larger crys-
tals were obtained, which were at times 0.5 cm. in length.
The nitrate crystallizes in orthorhombic prisms, terminated
by macrodomes and truncated by well-developed macropina-
coids and small brachypinacoids. The salt is not hygroscopic,
some crystals having stood in the open air for over a month
without losing their bright luster.

Purity of the Basic Nitrate of Tellurium,.

The purity of the basic nitrate of tellurium, which had
been twice recrystallized, was studied. It was again recrys-
tallized from nitric acid and a qualitative analysis of the crys-
tals was made. The mother-liquor was evaporated to dryness
and also analyzed. The presence of no foreign element was
detected in either case. Whitehead' and Keller^ have deter-
mined what substances are present in the crude copper from
which the tellurium used in this work was obtained. These
are silver, gold, bismuth, arsenic, antimony, and selenium.
As none of these elements forms a crystalline compound which
is diflScultly soluble in nitric acid, it is seen that the basic
nitrate of tellurium was readily obtained in pure condition.
Brauner has shown that pure tellurium cannot be obtained

1 J. Am. Chem. Soc., 17, 849.

2 Ibid., 19, 778.

Preparation of Pure Tellurium. 109

by precipitation, and that repeated distillation of the metal is
necessary to free it from the heavy metals.

In order to test for minute traces of selenium, a common
impurity in tellurium, the following method was devised,
based on the difference in behavior of the oxides of selenium
and tellurium with hydriodic acid. The former oxide is re-
duced and iodine set free, while the latter is converted into
the tetraiodide. The test is made in this way : About 0.15
to 0.2 gram of the oxide to be tested is dissolved in 2 cc. of a
10 per cent solution of sodium hydroxide, and 3 cc. of hydro-
chloric acid (sp. gr. 1.12) is added. The solution is then
cooled to the room temperature, carbon bisulphide and 2
drops of a dilute solution of potassium iodide (2 grams in 100
cc. water) are added, and the tube is shaken. Under the
above conditions, if selenium is present, the carbon bisulphide
will be colored by the iodine liberated, and the small amount
of tellurium tetraiodide formed will remain in solution. It is
necessary to avoid a large amount of potassium iodide in order
to prevent the formation of much tellurium tetraiodide, which
would dissolve in the carbon bisulphide and so obscure the
color of the iodine. Any doubt whether the color is due to
liberated iodine or to tellurium tetraiodide can be decided
definitely by shaking the carbon bisulphide with water. The
color produced by the iodine is not altered while the tellurium
tetraiodide is decomposed and the carbon bisulphide again
becomes colorless. The accuracy of the method was tested
by mixing known amounts of selenium dioxide with the tel-
lurium to be tested. Using the amounts given above, 0.0012
mg. selenium can be detected in the presence of 0.160 gram of
tellurium dioxide, that is about i part in 150,000. No sele-
nium could be detected in the oxide obtained from the pure
nitrate when this very delicate test was applied.

It is of interest to note here that a strong solution of potas-
sium iodide acidified with hydrochloric acid, is a ver}^ deli-
cate test for tellurium. The dark color produced is quite
characteristic, resembling somewhat in strong solution the
color of platinum solutions containing iodides. The difference
is readily shown, however, by dilution, when the color pro-
duced by platinum persists as a pink, while the color pro-

no Norris, Fay, ajid Edgerly.

duced by the tellurium disappears on account of the decom-
position of the iodide.

No foreign substance was found in the tellurium from the
nitrate by careful qualitative analysis, yet it was subjected to
additional tests. Brauner and Wills found that the purest
tellurium obtained by precipitation invariably left a residue
when distilled in hydrogen. A sample of the oxide prepared
from the nitrate was dissolved in pure hydrochloric acid and
the tellurium precipitated with sulphur dioxide and washed
until free from hydrochloric acid. The tellurium was then
distilled in a stream of hydrogen, which was prepared by the
action of sulphuric acid on zinc. The gas was purified by
the method used by Wills' in preparing pure tellurium for a
determination of its atomic weight. After the distillation a
bright stain was left on the porcelain boat. The tellurium
was redistilled a number of times with the same result. The
gray, shiny spot on the boat was not affected by hot sodium
hydroxide, hydrochloric, or nitric acid, and was not volatilized
by the heat of a blast-lamp.

From the following experiments it was shown that this resi-
due was due to the union of a small amount of tellurium with
the porcelain of the boat at the high temperature required for
the distillation. Some tellurium prepared from the nitrate
was next distilled in a vacuum. After the first distillation a
light gray substance was left in the boat. This was floccu-
lent, dissolved completely in dilute hydrochloric acid and
sodium hydroxide, and evidently was tellurium dioxide,
which is always present in precipitated tellurium. The tel-
lurium, when redistilled in vacuum, left no residue, but when
distilled in hydrogen a stain was left on the boat as before.
Some pure tellurium, obtained by distillation in a vacuum,
was heated on porcelain in a blast-lamp flame. A stain was
left which was caused by the combination of a small amount
of the tellurium with the porcelain. This does not take place
when the metal is distilled in a vacuum as the temperature
of distillation is lower.

The oxide prepared from the nitrate was also completely
volatile without leaving a residue. It was heated to redness

1 J. Chem. Soc, 35, 704.

Preparation of Pure Tellurium. iii

on a platinum foil placed inside of a porcelain cnicible. The
above experiments show that a careful examination of the
tellurium obtained by recrystallization of the basic nitrate did
not show the presence of any knowm substance.

Analysis of Basic Tellurium Nitrate.

As the basic nitrate obtained by crystallization from nitric
acid is a stable substance, and is not hygroscopic as Klein
and Morel have reported, a careful analysis of it was consid-
ered necessary. The water was determined by igniting the
substance, which had been previously dried at 120°, in a
current of oxygen for two hours. In the front part of the
tube was placed metallic copper to reduce the oxides of nitro-
gen. The nitrogen was estimated by a method which was
essentially that of Dumas. The tellurium dioxide was deter-
mined by heating the nitrate slowly until all of the oxides of
nitrogen were given off, and then fusing quickly the oxide
left. The decomposition of the nitrate was accomplished
most conveniently by placing the platinum crucible inside of
a larger porcelain crucible, which was heated by a Bunsen
burner. Alter an hour's heating the oxide was in the
form of a loose white powder. The results of the analyses
follow :

I. 0.7975 gram substance gave 23.25 cc. N at 0° and 760
mm. pressure.

II. 1.2222 gram substance gave 37.20 cc. N at 0° and 760
mm. pressure,

I. 2.0530 gram substance gave 0.0538 gram H^O.
II. 2.2981 gram substance gave 0.0590 gram H^O.

I. 0.9491 gram substance gave 0.7925 gram TeO^.
II. 0.9920 gram substance gave 0.8282 gram TeO^.

Calculated for Calculated for Found.

4Te03.N506.iiHj0. 4TeO,.N305.H20.

N 3.62 3.66

H,0 3.49 2.36

TeO, 82.54 83.52

The atomic weight of tellurium has been taken as 127.6 in
calculating the above results. Klein and Morel,' using 129
as the atomic weight of tellurium, obtained these results :

1 Bull. Soc. Chim. [2], 43, 198.

I.

II.

3-64

3.84

2.62

2.57

8349

83-36

112 Norris, Fay, and Edgerly.

Calculated for

Found.

4TeOj.N30j.iiH20.

I.

II.

N

3-59

3-70

....

H,0

3-47

2.90

3.80

TeO,

82.66

82.20

83-30

Te

65-57

66.10

66.50

Experiments described below show that there is no water of
crystallization in the compound. The formula therefore is
best written Te,03(0H)N0,.

Decomposilion of Basic Tellurium Nitrate by Heat.

Two samples of the nitrate were heated at gradually in-
creasing temperatures in order to determine whether the hy-
drogen in the compound is present as water of crystallization.
The substance was heated for two or more hours at intervals
of 10°, beginning at 110°. If at the end of that time the
weight had changed, the heating was continued without
changing the temperature until constant weight was ob-
tained. The results follow :

Number of Percentage loss,

hours heated. Temperature. I. II.

12 iio°-i70° 0.00 0.00

2 1 70''- 1 80° 0.07 0.03

4 i8o°-i9o° 0.42 0.26

II i90°-200° 2.47 3.36

9 200°-2IO° 3.71 4.15

9 2I0°-220° 4.02 5.85

6 220°-230° 8.00 9.67

9 230°-25o° 8.60 10.30

I About 350° 16.51 16.50

From the above results it will be seen that there is no loss
of weight up to 170°, when a slight decomposition begins.
At 190° oxides of nitrogen begin to be evolved. There was no
distinct point at which the water was given off. The decom-
position was gradual, both water and nitric acid being given
off at the same time. The figures in the last line of the table
give the results of heating two portions of the nitrate in cov-
ered platinum crucibles protected b}'- porcelain crucibles. The
results are practically the same as those obtained in the very
accurate determinations described later; viz., 16.47. ^"^^
oxide which was left was tested for nitric acid by phenol-sul-

Preparatio7i of Pure Tellurium. 113

phonic acid, and only a trace was found. It is therefore un-
necessary to fuse the oxide in making a gravimetric estima-
tion of tellurium, if it is heated in the manner described.
The loss which accompanies fusion can be done away with
and more accurate results obtained. The experiments re-
corded above are not in accord with the statement of Klein
and Morel that the nitrate begins to decompose at the fusing-
point of lead.

Action of Nitric Acid on the Nitrate.

In recrystallizing the nitrate it was observed that at times a
residue was left which dissolved with difl&culty in nitric acid-
This residue examined under the microscope showed well-
developed crystals in the form of octahedra, and, when igni-
ted, it did not lose in weight. The nitrate was changed into
a mixture of amorphous and crystalline tellurium dioxide. It
was therefore important to study the conditions of formation
of the oxide in order to be able to get crystals of the nitrate
in perfectly pure condition.

Some nitrate was heated with not enough nitric acid (sp.
gr. 1.20) to dissolve it. After the acid had boiled twenty-
five minutes the residue was examined and found to contain
no nitrate. From the hot solution a small amount of white
amorphous powder separated. On evaporation of the nitric
acid solution well-defined crystals of the nitrate were formed.
These were shown by analysis to be free of oxide. The loss
in weight on ignition was 16.51 per cent. Theory requires a
loss of 16.48 per cent. The same results were obtained when
nitric acid of specific gravity 1.25 was used. It will be seen,
therefore, that, while the dilute acids decompose the nitrate,
any crystals which are formed from it by concentration are
pure nitrate. The reasons for the directions given above for
the recrystallization of the nitrate, are now evident. The ni-
trate is stirred with the acid (sp. gr. 1.25) at about 70° in
order to avoid decomposition into the oxide, and saturation of
the solvent. Crystals of the nitrate increase markedly in size
when heated with concentrated boiling nitric acid, and a large
amount crystallizes from the oxide on cooling.

114 Norris, Fay^ and Edgerly.

Elecb'olytic Deposition of Tellurium.

Schucht' and Whitehead^ have shown that tellurium is de-
posited by the electric current from an acid or alkaline solu-
tion. Numerous attempts were made to get the conditions
under which the deposit would be made in such a form that it
could be weighed. It was deposited from hydrochloric and
nitric acid solutions and from solutions of the alkali tellurites.
As tellurium is nearest to antimony in the electrolytic scale,
the conditions under which antimony is deposited were ap-
plied to tellurium. The precipitate was always in an amor-
phous, flocculent condition. Some tellurium which had been
deposited by electrolysis was converted into the nitrate and
the loss in weight on ignition determined. This was done to
determine whether the electrolysis had effected any decompo-
sition of the element. As the loss in weight was 16.55 P^r
cent, it was concluded that no decomposition had taken place.

Fractional Crystallization of Potassium Bromtellurate.

Owing to the uncertainty of the homogeneity of tellurium
it was subjected to a careful fractionation. Wills'' fused tel-
lurium with potassium cyanide and precipitated the element
in two fractions from the aqueous solution of the telluride by
a current of air. Brauner used this same process but separa-
ted the tellurium into four fractions. He also precipitated
tellurous acid in eight portions from a solution of tellurium
tetrachloride, and subjected tellurium tetrabromide to frac-
tional sublimation in a vacuum. The details of the latter
method are not given.

Staudenmaier'' crystallized telluric acid and collected the
compound in four portions. In all cases atomic weight de-
terminations of the fractions gave no evidence of a breaking
down of the tellurium.

The importance of testing the hypothesis of the compound
nature of tellurium led us to undertake a more careful frac-
tionation than had been accomplished heretofore. The re-
sults of Wills, Brauner, and Staudenmaier are not conclusive,
since the fractionation was not carried far enough in any case

1 Jahresbericht, 1S83, 222, 1514. 2 j. Am. Chem. Soc, 17, 849.

3 J. Chem. Soc, 35, 704. * Ztschr. anorg. Chem., 10, 1S9.

Preparation of Pure Tellurium , 115

to warrant definite conclusions. Cr5-stallization was selected
as the means of fractionation, as it appears to be much more
efficient than precipitation. A number of compounds were
studied with the view of using them for this purpose. The
organic compounds formed by tellurium tetrachloride with
anisolandphenetol, TeCl^CC.H^.OCH,),, TeCl,(C,H,OC,H,)„
were prepared. They are described as crystallizing well.
The progress of the crystallization could be easily watched as
the compounds have distinct melting-points. It was found
extremely difficult, however, to prepare these compounds in
large quantities and to recrj^stallize them.

The salt finally selected was the double bromide of tellu-
rium and potassium. This salt is readily prepared and crys-
tallizes well from water. In order to have the results of the
fractionation as conclusive as possible all the reagents used
were prepared with the greatest care.

Potassium bromide was prepared by heating chemically
pure potassium bromate of commerce which had been recrys-
tallized four times. Hydrobromic acid was made by Squibb's
method, and purified by four redistillations from potassium
bromide. The tellurium dioxide was made from basic nitrate
which had been recrystallized three times from nitric acid.
The nitrate was decomposed at about 350° and then fused in
portions of 6 to 10 grams in a platinum crucible protected by
a larger porcelain crucible. Theoretical quantities of tellu-
rium dioxide and potassium bromide were dissolved in hydro-
bromic acid and the salt obtained by crystallization. Through-
out the work porcelain dishes alone were used. Eight hun-
dred grams of this compound were then subjected to frac-
tional crystallization.

The following diagram may help to make the scheme of
fractionation clear. Crystals are represented by solid lines
and mother-liquors by dotted lines :

1234
•n 5 X\ 6 /\ 7 /

\/ \/ ^-y

I' 2' 3' ^

ii6 Norris^ Fay, and Edgerly.

Four portions of 200 grams each were dissolved in water,
usually containing a small amount of hydrobromic acid, and
the solutions evaporated to such a point that about 100 grams
of salt separated on cooling. The salt from fraction i was set
aside ; the salt from fraction 2 was added to the mother-
liquor of fraction i , making number 5 ; the salt from number
3 was added to the mother-liquor from number 2 ; and the
salt from 4 was added to mother-liquor number 3. The
mother-liquor from fraction 4 was set aside during the inter-
mediate crystallization of fractions 5, 6, and 7. These solu-
tions were evaporated as before. The salt from fractions i
and 5 were united, making the first portion of the second
series. The mother-liquor of number 5 and the crystals from
6 made number 2 of the second series. The mother-liquor of
6 and the crystals from 7 made number 3, and finally the
mother-liquors of 4 and 7 made number 4 of the second series.
It will be seen that a complete series involves seven crystal-
lizations. This procedure of adding the crystals of one frac-
tion to the mother-liquor of another tends to make the most
soluble and the least soluble portions collect in the end frac-
tions. The fractionation was repeated thirty times, which in-
volved 215 crystallizations.

There were no indications during the work of any change
in the salts, so an atomic weight determination of the tellu-
rium from the end fractions had to be made. More than fif-
teen different methods have been studied in attempting to
determine the atomic weight of tellurium, and of these but
one method, the determination of bromine in the tetrabro-
mide, was found to give concordant results. As the use of
this method is not free from objections, and involves a large
amount of work, a simpler method was sought. Very con-
cordant results were obtained in the analysis of the basic ni-
trate when it was changed to the oxide by ignition, and it
seemed possible that trustworthy results, which -would show
any variations in the atomic weight, might be obtained, if the
ratio between the nitrate and oxide was determined with great
care.

As Klein and Morel have stated that the nitrate is hygro-
scopic, experiments were made with a pure sample to test this

Preparation of Pure Tellurium. 117

point. Two portions of the salt were heated for eight hours
at 120° in platinum crucibles, transferred to a desiccator, and
after cooling were weighed immediately, a platinum crucible
being used as a tare. After standing half an hour and fifteen
hours in the balance case, the crucibles were weighed again,
with the following results :

Hours.
O

15.0

It will be seen that the weights remained perfectly constant
after the crucibles had stood long enough to be in equilibrium
with the atmosphere of the balance case, which shows con-
clusively that the salt is not hygroscopic. It was then
heated at 120'' for varying periods of time to determine
whether it could be brouo:ht to constant weight.

A.
1.96242

B.
2.19839

1.96275

2.19860

1.96274

2.19855

Hours heated.

A.

B.

2-5

2.28692

2.12905

14.0

2.28667

2.12897

7-5

2.28676

2.12896

7.0

2.28672

2.12905

The above results show that this could be done very satis-
factorily.

The preliminar}^ experiments on the decomposition of the
nitrate showed that the oxides of nitrogen evolved during
heating carried off a small amount of tellurium dioxide me-
chanically. In order to avoid this loss the following device
was used : A platinum crucible was provided with two remov-
ble platinum disks which fitted the crucible at distances of about
one-half and one inch from the bottom. In the center of the
lower disk a hole was cut about one-eighth inch in diameter.
The salt was placed in the crucible, the disks adjusted, and
the cover put on. There were three surfaces over which the
issuing gases had to pass, and on these the oxide carried along
was deposited. In the experiments a slight dullness was
visible on the upper disk, but the cover was bright, thus
showing that no oxide had reached it.

The nitrate was decomposed slowly in order to avoid a rush
of gas. It was heated for two hours at 200°, 250°, and 300° ;

ii8 Norris, Fay, and Edgerly.

three hours at 350°, 400°, 450°, 500°, and 550° ; and was
finally fused quickly in the oxidizing flame of a Bunsen
burner.

The tellurium from the two end fractions of the fractional
crystallization was converted into nitrate. The salt was
moistened with concentrated nitric acid when being ground
in order to prevent decomposition from atmospheric moisture.
The finely divided nitrate was heated to constant .veight and
converted into the oxide in the manner described above.

The results of the analysis of the nitrate prepared from the
tellurium from the fraction which would contain the most sol-
uble portion, follow :

Tes03(0H)N03.

TeO,.

Percentage TeOj,

I.

2.84426

2.37354

83.45

II.

2.55736

2.13397

83.44

The analysis of the nitrate from the fraction which would
contain the least soluble portion, was made under the same
conditions as before.

Tej03(OH)N03.

TeO,.

Percentage TeOj.

III.

1.39948

I. 16824

83.48

IV.

1.85244

1.54649

83.49

The difference between the average of determinations I and
II and the average of III and IV corresponds to a difference
of 0.4 in the atomic weight. When a sample weighing 2 grams
is used an error of 0.3 mg. in the weight of the nitrate would
affect the atomic weight to this extent. Although the
weights of the nitrate in the above experiments appear to be
accurate to o.i mg., nevertheless the difference found is
probably more apparent than real.

The basic nitrate is a crystalline compound and may have
held mother-liquor within the crystals, although the salt was
ground to a fine powder and did not lose weight when heated
for ten hours at 120°. On account of this uncertainty, we do
not consider the results as data which can be used for calcu-
lating the atomic weight of tellurium. The results are of
value, however. The analyses of the nitrate prepared from
the fractionated tellurium were made under exactly the same
conditions, and any error in the method would have affected

Reduction of Selenmm Dioxide. 119

the two determinations equally. We can, therefore, safely
conclude that the fractionation of potassium bromtellurate did
not effect any decomposition of the tellurium, which could be
detected by a method capable of giving results accurate to 0.4
of a unit in the atomic weight.

The work described above is preliminary to an atomic
weight determination which is now in progress. When a
method has been devised which will give accurate results, the
atomic weight from the end fractions will be determined, in
order to decide whether the difference of 0.4 of a unit indica-
ted by the experiments given above is a real one or not. We
hope also to offer more conclusive evidence in regard to the
elementary nature of tellurium. The fractional sublimation
of tellurium dioxide, which is now in progress, seems to offer
a more efficient means of deciding this point than fractional
crystallization.

This paper has been published in this unfinished form, as
the departure of one of us from the Institute prevents us from
continuing the work in common.

Boston, Dec. i, 1899.

XXIV.— THE REDUCTION OF SELENIUM DIOXIDE
BY SODIUM THIOSULPHATE.

By James F. Norris and Henry Fay.

Some time ago we proposed a volumetric method for the
estimation of selenous acid' based on the reaction between it
and sodium thiosulphate in the presence of hydrochloric acid.
The procedure, in brief, is as follows : The solution in which
the selenous acid is to be determined is diluted with ice-
water, acidified with dilute hydrochloric acid, and an excess
of a tenth-normal solution of sodium thiosulphate added. The
excess of thiosulphate is determined by titration with a
solution of iodine. It was shown that i molecule of selenous
acid reacted with 4 molecules of sodium thiosulphate, and
that the reaction afforded a means for the accurate determina-
tion of selenium.

1 This Journal, 18, 703.

I20 Norris and Fay.

At the time this method was proposed we were not able to
state the exact nature of the reaction, but we have studied
further the reduction and are now able to write the complete
reaction. The most probable reaction between the two sub-
stances may be represented by the following equation :

SeO, H-4Na,S,0, — 2NaA0, + Se + 2Na,0.

If strong solutions of selenium dioxide and sodium thiosul-
phate are mixed, selenium is precipitated, and the solution
shows an alkaline reaction. In dilute solutions, on the other
hand, no selenium is precipitated, and the reaction is not
complete according to the above equation, since the sodium
hydroxide formed neutralizes a part of the selenous acid
which, accordingly, does not enter into the reaction. If,
however, acid is present, 4 molecules of sodium thiosulphate
react with i molecule of selenium dioxide. The amount of
acid required to complete the reaction was determined. This
was found to vary with the dilution, the excess of thiosul-
phate, and the time of reaction. The following table gives
the results obtained. In each case 10 cc. of a solution of
selenium dioxide, which was equivalent to 26.40 cc. of sodium
thiosulphate, according to the ratio SeO, : 4Na,S503, were
used :

Molecules

NajSjOj

Na,S,Oj

Water

HCl.

taken.

used.

added.

cc.

cc.

cc.

I.

3

50

17.90

II.

4

27

22.02

300

III.

4

27

24.96

300

IV.

4

50

25.40

300

V.

5

30

26.38

300

VI.

4

50

26.40

In experiment I., 3 molecules of acid were used and only
17.90 cc. of thiosulphate entered into the reaction. Using 4
molecules in II, 22.02 cc. of thiosulphate reacted. In the
third experiment the same proportions were used, but the
solutions stood forty minutes before the excess was deter-
mined. This had a marked effect on the result, as about 3
cc. more of the thiosulphate reacted. A large excess of thio-
sulphate hastened the reaction, as is shown in experiment

Reduction of Selenium Dioxide. 121

IV. Experiment V shows that 5 molecules of acid are suffi-
cient at a dilution of 300 cc, and with a slight excess of
sodium thiosulphate to complete the reaction. In experi-
ment VI no water was added to the solutions used and the re-
action was complete when the proportion of the reagents were
SeOj : 4Na,Sj03 : 4HCI. These are, therefore, the amounts
of reagents which enter into the reaction.

In order to determine the products of the reaction, a solu-
tion of the constituents in the above proportions was prepared.
The study of this solution led to the following equation,
which expresses the reaction :

SeO, + 4Na,S,03 + 4HCI =

Na,S,SeO, + Na,S,0, + 4NaCl + 2H,0.

The formation of sodium selenopentathionate, similar to
potassium pentathionate, seemed probable, since no selenium
was precipitated as a result of the reduction. Debus,' in an
exhaustive stud}' of Wackenroder's solution, which is pre-
pared by the action of hydrogen sulphide on an aqueous solu-
tion of sulphur dioxide, isolated some salts of pentathionic
acid in a pure condition, and carefully studied their proper-
ties. He gives the following characteristic reactions :

" I. An ammoniacal solution of silver nitrate causes, in a
solution of potassic, ammonic, or baric pentathionates, a
brown coloration which rapidly becomes darker, and by de-
grees a black precipitate is thrown down from the mixture.
This reaction is not produced in a solution of tri- or tetrathio-
nates, potassic thiosulphate, or ammonic sulphite. An am-
moniacal solution of silver nitrate also seems to have no effect
on them. Consequently a pentathionate, even if present in
very small quantity, can be detected by means of this reac-
tion in a mixture containing potassic tri- and tetrathionates,
and sodic, potassic, or ammonic thiosulphates.

" II. Potassic hydroxide, in solutions of pentathionates,
immediateh' produces a separation of sulphur. As tri- and
tetrathionates and thiosulphates are not changed by this re-
agent, a proportionally small quantity of a pentathionate can
be detected in a mixture of the four salts by addition of
potassic hydroxide.

1 J. Chem. Soc, S3, 278.

122 Norris and Fay.

" III. Ammonia added to a solution of potassic pentathio-
nate causes, after about one or two minutes, a precipitation of
sulphur.

"IV. Hydric chloride does not change solutions of tetra-
and pentathionates. "

A solution prepared by mixing the constituents in the pro-
portions represented in the equation, was subjected to the
above tests. A precipitate was formed with ammoniacal sil-
ver nitrate, as described above under I, and potassium h}'-
droxide caused an immediate precipitation of selenium. Am-
monia acted more slowly, and the solution was stable toward
strong hydrochloric acid. The solution showed, therefore,
the characteristic reactions of a pentathionate, selenium, how-
ever, being precipitated instead of sulphur. This is in accord
with the formula proposed, Na^S.SeOc. An effort was made
to isolate the selenopentathionate, but without success, as
selenium was always precipitated when the solutions were
concentrated by heat or in a vacuum. From the solution,
however, we were able to isolate sodium tetrathionate, which
was proved to be such by qualitative and quantitative analy-
sis.

A dilute solution containing the new salt could be boiled
some time without change. A number of neutral salts were
found to decompose the compound. Stannous chloride
caused a precipitation of selenium after a few minutes. A
dilute solution of sodium thiosulphate produced the same
effect only much more slowly, whereas a number of hours'
standing was necessary before potassium iodide caused any
decomposition.

An acid solution of tellurium dioxide is reduced by sodium
thiosulphate, giving a bright yellow solution, from which
sodium hydroxide precipitates tellurium. Tellurium, there-
fore, probably forms a compound analogous to a selenopenta-
thionate. This is remarkable, since no compounds contain-
ing tellurium, analogous to the thionates, are known. Crane'
attempted to prepare substances similar to the thiosulphates,
by boiling sodium tellurite with sulphur, selenium, and tellu-
rium, but there was apparently no reaction.

1 Dissertation, Johns Hopkins University.

Reductio'/i of Selenium Dioxide. 123

By misunderstanding a statement made in our former
paper, Mr. J. T. Norton, Jr.,' has been led to study the influ-
ence of hydrochcloric acid on titrations with sodium thiosul-
phate, and to repeat our work on the estimation of selenium.
He says, referring to the method, " the explicit statement of
the authors that the amount of hydrochloric acid present does
not influence the result provided the titration is made at the
temperature of melting ice, is so extraordinary in view of
generally accepted ideas in regard to the interaction of hydro-
chloric acid and sodium thiosulphate as to suggest the neces-
sity of a careful investigation of this point." In the paper
referred to we made this statement : " It was found necessary
to have enough hydrochloric acid present to set free all of the
thiosulphuric acid. If the solution is cold a large excess of
hydrochloric acid does not affect the titration." Mr. Norton
evidently confuses excess with amount. We used in all of our
experiments 10 cc. hydrochloric acid (1.12 sp.gr.), which is
seven to eight times the amount required according to the
above statement, and obtained excellent results. The state-
ment is, therefore, not so extraordinary as might appear.

As the action of hydrochloric acid on sodium thiosulphate
was known to us when we were making a study of the
method, we took the precautions to have the solutions con-
taining the acid dilute, and used ice to keep the temperature
as low as possible. The necessity for these precautions was
stated in the directions given, Mr. Norton further points out
that it is advisable to use not more than 20 cc. excess of
sodium thiosulphate in order to prevent decomposition by the
acid. We have made some new determinations of selenium
in order to test the directions given in the original paper un-
der the most unfavorable conditions. The results follow :

NajSoOj

SeOj

NagSjOs

used in

SeO,

taken.

taken.

reaction.

found.

Dilution.

Gram.

cc.

cc.

Gram.

cc.

I

0.0995

43

39.62

0.0995

300

II

0.0336

15

13-39

0.0336

300

III

0.0336

50

13-13

0.0331

300

IV

0.0336

50

13-24

0.0333

300

V

0.0435

50

17.20

0.0432

400

VI

0.0430

50

16.41

0.0412

200

1 Am. J. Sci., 157, 2S7.

124 ^ Norris and Fay.

In Experiments I. and II. the directions as given in our
paper were followed, and a small excess of sodium thiosul-
phate was used. In order to have a large excess of thiosul-
phate present in the other experiments, small amounts of sele-
nium dioxide and 50 cc. of thiosulphate were used. In III.
and IV. the excess, 36.87 cc, was nearly three times the
amount necessar}^ for the reaction — 13.13 cc. Since a bare
excess only is necessary, a careful analysis would ''•ardly be
based on such a procedure. Experiment VI. shows the neces-
sity of working in dilute solutions. In all of the above deter-
minations 10 cc. hydrochloric acid (1.12 sp. gr.) were used,
but since 5 cc. is quite sufl&cient to bring about the reaction,
the modification which Mr. Norton suggests as the result of
his work, namely the use of the latter amount of acid, can
readily be accepted.

Mr. Norton points out also that his results always come
high. We had not observed this in our work and accordingly
we sought the cause. As we had standardized the sodium
thiosulphate by titration against known weights of iodine,
under the conditions which were to be used in the subsequent
analyses, that is, titration in the cold in the presence of acid,
a standardization was made under ordinary conditions. The
factor found was higher by about 0.2 per cent than the one
previously obtained. This discrepancy was shown to be due
to the fact that the iodine-starch reaction is more sensitive at
3° in presence of dilute acids than under the conditions which
are ordinarily used in the titration of iodine and thiosulphate.
The following table gives the number of cubic centimeters of
one-hundredth normal iodine solution required to produce a
color with starch under different conditions of temperature and
with varying amounts of dilute hydrochloric acid (sp.gr. 1.12).
The starch solution was made by grinding 2 grams of soluble
starch with 5 cc. of cold water, and pouring the mixture into
500 cc. boiling water. In all tests 5 cc. of this solution were
used and diluted to 300 cc. with water.

Ac{io7i of Picryl Chloride. 125

No.

Acid.

Temperature.

Iodine

cc.

cc.

I

....

20°

0.61

2

1. 00

20°

0.32

3

10.00

20°

0.26

4

50.00

20°

0.27

5
6

• • • •

3°
15°

0.30
0.50

7
8

....

20°

25°

0.57
0.85

9

30°

I. 17

10

10.00

3°

0.15

Experiments 1-4 show the effect of acids and 5-9 the effect
of temperature. In Experiment 10 the most favorable condi-
tions for the reaction were combined and 0.15 cc. of the iodine
solution gave a distinct color, whereas in the absence of acid,
at 25°, 0.85 cc. was necessary. It has long been known
that temperature has an effect on the blue compound formed
by the action of iodine on starch but, as far as we can find, it
has never been shown that this effect is appreciable at the
•temperatures used in the course of an analysis. Although the
error arising is small when the facts brought out by the above
experiments are overlooked, nevertheless, when very accurate
results are desired, they should be taken into consideration.

Boston, Dec. i, 1899.

ACTION OF PICRYE CHEORIDE ON PYROCATE-

CHIN IN PRESENCE OF AEKAEIES.

By H. W. HiLLYER.

Being engaged in a study of some derivatives of diphenyl
ether, C^H^OC^H^, made by the general method of Willgerodt,'
the attention of the writer was called to the reaction discov-
ered by G. S. Turpin,"^ and used by him in the preparation of
dinitrophenoxazine and to the reaction used by F. Kehrmanng
in preparing dinitropheuthiazine. Turpin brought together
in alcoholic solution one molecular proportion of picryl chlo-
ride, one of orthoamidophenol, and two of an alkali. He
readily obtained dinitrophenoxazine with the elimination of
chlorine, and one nitro group from the picryl chloride as fol-
lows :

1 Ber. d. chem. Ges., 12, 1278 ; and 13, 887. 2 j. Chem. Soc. (I^ondon), 1891, 714.

3 Ber. d. chem. Ges., 32, 2605.

126 Hilly er.

/NH, Ck

C.H / + >CeH,(NO,), =

\0H NO/

/

NH\
O

C,H,<^ p>C.H,(NO,), + HCl + HNO,

In this connection the idea came to the writer to ascertain
whether a similar reaction would take place on bringing to-
together picryl chloride and pyrocatechin in equimolecular
proportions and adding a double molecular proportion of
sodium hydroxide, thus forming a double aromatic ether.

Fifteen grams picryl chloride and 6.6 grams pyrocatechin
were dissolved in 500 cc. common alcohol and a solution of
sodium in alcohol, equivalent to 4.8 grams of sodium hydrox-
ide, were added. The solution turned dark-brown, and after
some time deposited a brown precipitate soluble in water.
The mixture was heated to 6o°-7o° for six hours. The brown
precipitate gradually disappeared, and was replaced by a
dense, yellow, granular precipitate, which, after five hours,
did not seem to increase in amount. It was filtered from the
solution and washed with alcohol and water, and after drying
weighed 13.75 grams, or 85 per cent of the theoretical. The
solution filtered from the yellow precipitate contained large
quantities of chloride and nitrite.

The crude yellow product melts at I9i°-i92°.5. It dissolves
quite readily in hot benzene, and crystallizes from it on cool-
ing in yellow spherulites. It is best purified by crystalliza-
tion from hot glacial acetic acid, from which it also separates
in lemon-yellow spherulites. By this purification its melting-
point is changed but little, the melting-point of the twice
crystallized substance being 192°-: 92°. 5. When rapidly
heated it decomposes almost explosively, but when carefully
heated it may be sublimed in the form of beautiful lemon-yel-
low leaflets of the same melting-point. It will not dissolve in
hydrochloric acid. It dissolves in concentrated sulphuric
acid, but apparently separates unchanged on adding water.
It will not dissolve except perhaps slightly in dilute alkalies,
showing that it is not a phenol. Heated with strong alkalies
it dissolves, forming a brown solution, and from this solution

Action of Picryl Chloride.

127

a new substance not yet studied is thrown down on adding an
acid.

A portion of the yellow substance twice crj'stallized from
glacial acetic acid, washed with alcohol, and dried for one
hour at i30°-i4o° was analyzed, and gave the following re-
sults :

I. 0.221 1 gram substance gave 0.4283 gram CO,, and 0.0486
gram H,0.

II. 0.2093 gram substance gave 0.4005 gram CO,, and
0.0431 gram H^O.

III. 0.2477 gram substance gave 23.2 cc. N at 21° and 748
mm. pressure.

Calculated for Found.

C(,H405C8H4(N05)3. I. II.

C 52.55 52.83 52.18

H 2.19 2.44 2.29

N 10.22 .... 10.49

In view of these analytical results and of the formation of
chloride and nitrite in making it, and also from its not being
a phenol, the substance may be represented by the formula

N0„

-O-
■0-

N0„

and is produced by the reaction

N0„

ONa CI
ONa NO

NO,

N0„

-O—
-O—

-h NaCl 4- NaNO,

NO,

128 Noyes.

It is a 1,3-dinitroorthodiphenylene dioxide. In view of the
stability of the phenyl ethers, it seems probable that the
mother-substance of which this is a dinitro derivative may
yield other interesting derivatives. For the mother-substance,
to indicate its analogy with phenoxazine and phenthiazine,
and to point out the presence of the two oxygen atoms con-
necting the two phenylene groups, the name phenoxozone is
proposed.

The action by which the new substance, dinitrophenoxo-
zone, is prepared presents one more case of which there are
now several in which a nitro group may be split off with
formation of a closed chain. The cases published are cases
in which the nitro group is in the ortho position to a side
chain, usually nitrogenous, and of such a character that it
can form either a five-membered or six-membered ring. In
the present case there is a formation of a six-membered ring
of four carbon atoms and two oxygen atoms.

It is desired to reserve, for study in this laboratory, the
action of orthonitrohalogen benzene derivatives on di- and
poly-acid phenols of the ortho series, and the character and
reactions of the derivatives of diphenylene dioxide or phenox-
ozone.

Laboratory of Organic Chemistry,
University of Wisconsin,
December 20, 1899.

Contributions from the Chemical Laboratory of the Rose Polytechnic Institute.

XVII.— CAMPHORIC ACID.
[eighth paper.]

By William A. Noyes.

An account of the preliminary work toward the synthesis of
2.33-trimethylcyclopentanone has already been given.' The
synthesis has now been brought to a successful completion.

Ten grams of sodium were dissolved in 130 cc. of absolute
alcohol and 92 grams (calculated 76.5 grams) of methvl ma-

/CO,C,H,
Ionic ester, CHg — CH<' , were added, and then 97

^CO,C,H,
grams of the ethyl ester of ;^-bromisocaproic acid,

1 This Journal, 22, 25S.

Ca^nphoric Acid. 129

CH,.

>CBr.CH,CH,.CO,C,H..
CH,

• Vi'*-".. ■w^ij'wi^j. -.^v^j-wj^^j.

The mixture was boiled for two hours, filtered from sodium
bromide, the alcohol distilled over a free flame, the residue
filtered again, and then distilled under diminished pressure.
After two distillations there were obtained 5 grams of an ester
boiling at i8o°-i87° under a pressure of 20 mm. A second
preparation with the use of 121 grams of the brom ester gave
8.1 grams, boiling at i7o°-i8o° under a pressureof 13-15 mm.
The portion boiling at 178°-! 80° was analyzed.

I. 0.1930 gram substance gave 0.4244 gram CO^, and
0.1404 gram H3O.

II. 0.2010 gram substance gave 0.4425 gram CO,, and
0.1473 gram H,0.

Found.

60.04
8.12

The ester was evidently contaminated with some compound
or compounds containing less carbon and hydrogen, but, ow-
ing to the difficulty of preparation, it could not be further
purified. The ester of the first preparation was saponified by
boiling for one hour with alcoholic potash. The solution was
•diluted, evaporated to remove alcohol, acidified, and extracted
several times with ether. The impure 2.33-tetramethylhex-
oic 1,2',6-acid,

/CO,H
CH3-C<(

CH,. I

> C— CH — CH — CO,H ,

cn/

was heated in an oil-bath to 200"^ for a few minutes till the

Calculated for

^COjCjHj

CH,-C<

1 \CO5C3H5

CH3\ 1

>C— CHj.CHjCOjCaHj
CH3/

I.

c»

60.76

59-97

Jbisa

8.86

8.08

0.

30.38

....

1 30 Noyes.

evolution of carbon dioxide ceased. The resulting afi^-tr'i-
methyladipic acid was mixed with twice its weight of lime
and the mixture distilled from a small distilling-bulb. The
distillate was distilled and 0.35 gram, which passed over at
i6o°-i8o°, was mixed with alcohol and a solution containing
0.6 gram of hydroxylamine chloride and 0.5 gram of sodium
hydroxide. After several hours the solution was poured into
a crystallizing dish, and allowed to evaporate spontaneously.
The oxime which separated was recrystallized from ligroin.
It crystallized in needles which melted at 104°. When a
small portion was mixed with an equal amount of the oxime
prepared from a-hydroxydihydrociscampholytic acid,' the
mixture melted at exactly the same temperature, and after
solidification the melting-point still remained the same. The
identity of the two substances is, therefore, established, and
the ketone from camphor is 2.33-trimethylcyclopentanone.
From this it follows that ciscampholytic acid is the -^'-2.33,-
trimethylcyclopentenoic acid,

CH3— C=:C— CO,H

I

CH,
CH3. I

CH

/

There also remains no reasonable doubt that Perkins"^ older
formula for camphoric acid,

CO,H

I
CH — C— CH— CO,H

I
CH„

ca

CH,

)>C-CH,

and Bouveault's^ formula for camphor,

1 This Journal, as, 265.

2 Proc. Chem. Soc, 1896, 191.
schem. Ztg., 21, 762.

Camphoric Add. 131

CO— CH,

I I

CH,— C — CH

I
CH„,

CH,.

> I

CH

/

CH„

are correct.

Owing to the small quantity of the oxime available, the
analysis was not satisfactory.

0|f^53 gram substance gave 0.0387 gram of nitrogen.

Calculated for
C8H,4NOH. Found.

N 9.93 10.96

The ester from the second preparation above was saponified
by longer boiling with alcoholic potash, and there was ob-
tained from it an acid which partly solidified. By treatment
with a small amount of ether the pure 2.33-tetramethylhexanoic
1,2',6-acid was obtained. The acid crystallizes from ether
in needles. When heated it begins to decompose at about
175°, but does not melt to a clear liquid till a somewhat higher
temperature is reached. When heated to i90°-20o° for a few
minutes it is decomposed quantitatively into carbon dioxide
and ayS/?-trimethyladipic acid. The ammoniacal solution of
the acid gives no precipitate with calcium chloride in the
cold, but, on warming, a precipitate is formed, which redis-
solves on cooling.

0.1226 gram of the acid gave 0.2319 gram CO,, and 0.0780
gram H^O.

Calculated for
/CO,H
CH3-C<

XOjH
CH,s. I

>C— CH5CH5CO5H.
CH,/ Found.

C:„ 51-72 51-59

H,e 6.90 • 7.07

O.

0.65 gram of the pure trimethyladipic acid obtained by heat-
ing a portion of the acid last mentioned to 200° was mixed
with 2 grams of lime and the mixture distilled from a small

132 Noyes.

distilling-bulb. The decomposition took place with very lit-
tle blackening and a light-yellow oil passed over. This had
the peculiar peppermint, musty odor, characteristic of the
2.33-trimethylcyclopentanone from camphor. It was partly
purified by distilling with steam, and an attempt was made to
prepare the condensation-product' with benzaldehyde. The
condensation took place easily, but a viscous oil was formed
from which no crystals could be obtained. Ur fortunately,
none of the condensation-product from the preparation from
camphor remained with which to start the crystallization.
While the failure to secure the crystallized condensation-prod-
uct is disappointing, it cannot be considered that it throws
any doubt on the positive result obtained with the oxime.

The demonstration of the correctness of Perkins' older for-
mula for camphoric acid and of Bouveault's formula for cam-
phor, which has been furnished above, renders it possible to
discuss, with some degree of certainty, the transformations
which these bodies undergo. Only a few points will be taken
up for consideration in the present paper.

Blanc has recently* expressed the opinion that camphanic
acid is a ^-lactone having the structure,

CO— O

I I

QH.—Q — C— CO,H.

i

CH,
CH3. I

Nf" — CH„

CH

/

The formation of this acid from bromcamphoric anhydride
appears to furnish a strong basis for this view. In the opinion
of the writer, however, it appears more probable that the acid
in question is a normal ;K-lactone, and for the following rea-
sons :

Neither of the ^-hydroxy acids formulated below gives a
lactone directly.

1 This Journal, 22, 265.

2 Bull. Soc. Chirn., 19, 353.

Ca^nphoric Acid,

133

OH

CO„H

CH— C— CH— CO,H

CH,— C— CH— OH

CH,

CH,

CH„

3\ I

>C-CH,
CH3/

/3-Hydroxylauronic
acid.'

CH,

CH/

/3-Hydroxydihydro-
campholytic acid.^

Further, camphanic acid loses carbon dioxide and gives
campholactone and lauronolic acid^ on distillation. Campho-
lactone is also formed on warming }^-lauronolic acid with dilute
sulphuric acid.^ ;^-Iyauronolic acid must be a /Jj^-unsatura-
ted acid (see below) and the formation of a ^-lactone from it
is highly improbable.

The consideration of camphanic acid as a ^/-lactone also fur-
nishes a much more satisfactory explanation of the formation
of camphoronic acid from camphoric and camphanic acids
than if we consider it a /^-lactone. The steps appear to be as
follows: the transformation of the first oxidation-product to
camphanic acid being accomplished by the elimination, ad-
dition, and a second elimination of water. Such transforma-
tions take place with peculiar ease in this series :

CO,H CO O

I /CO,H I

CH — C— C < CH,— C— CH— CO„H

I ^OH
CH,

C— CH,

CH.s^

First oxidation-product.

CO,H

CH,
CH

\
/

CH-

C— CH,

Caniphanic acid.
CO,H

CH,— C— CH— CO,H

CH,^

chX

CO

I

C— CH,

1 This Journal, 17, 424.

^ Ann. Chem. (lyiebig), 227, 10.

CH— C— CH,

CH,^

ch/

CO

C— CH,

2/*irf., 18, 6S7.

4 This Journal, 17, 433.

134 No-yes.

CO,H

I
CH3-C— CH— CO,H

CH3.

>C— CO,H
CH3/

Camphoronic acid.

In a previous paper' the opinion has been expressed that
the " cistrans"-campholytic acid and ciscampholytic acid are
stereomeric. In the light of our present knowledge the two
acids would be formulated thus :

CH,

CH.

>

C=C CH,

I
CO,H

CH,

CH,— C:=C— CO,H

I
CH,

I
-CH,

CH.

CH,^

Cistranscampholytic acid.

>-

CH3

Ciscampholytic acid.

While the formula for cistranscampholytic acid here given
is not considered as established, it appears to be more in ac-
cordance with the facts now known than that given by Blanc,*
who considers the acid to be a ^;^- unsaturated acid.

Lauronolic and )/-lauronolic acids, apparently, have each the
formula

CO,H

I
CH,— C— CH

CH,
CH.

CH

>^-

C— CH,

Such an acid is optically active, and it is possible that
)^-lauronolic acid is one of the optical isomers, and that lau-
ronolic acid is the racemic form. It is my purpose to under-
take, as soon as possible, a systematic study of these four
acids with the hope of clearing up their relationships.

' This Journal, 17, 423.
2 Private communication.

Rearrangement of Imido-esters. 135

It has been found that when the sodium derivative of the
methyl ester of cyanacetic acid acts on the ethyl ester of
;/-bromisocaproic acid the same dimethylcyancarboxethylcy-
clopentanone described in my last paper,' is formed. The
melting-point of the product is the same, and the analysis
gave 6,79 per cent of nitrogen. Calculated 6.70 per cent.
The structure of the substance is, therefore,

CO,C,H,
I
CN— C— CO.

I

CH,
CH. I

>C-CH,
CH,/

It is hoped that the synthesis of camphoric acid, itself, may
be effected with the aid of this compound.

Terre Haute, Dec. 19, 1899.

Contributions from the Sheffield Laboratory of Yale University.

LXXIII.— ON THE REARRANGEMENT OF IMIDO-
ESTERS. .

[second paper.]

By Henry I,. Wheeler.

As described in our' first paper on this subject, we had oc-
casion to prepare phenylformimidoethyl ester, and, instead of
following the usual method^ of treating silver formanilide with
ethyl iodide at low temperatures, we heated the materials in a
closed tube to 100°. We thereupon unexpectedly obtained a
rearrangement of phenylformimidoethyl ester into the iso-
meric ethyl anilide :"

1 This Journal, 23, 260.

2 Wheeler and Johnson : This Journal, 21, 185.
8 Comstock : This Journal, 13, 514.

4 The prediction of Freer and Sherman in regard to this salt is now completely
fulfilled, i. e.y " With suitable alkyl or acyl halides and alteration of conditions, it will
probably be possible to procure both oxy and nitrogen derivatives from the silver
salt " (This Journal, 18, 571). In This Journal, 18, 381, Wheeler and Boltwood
showed that this salt gives in fact benzoylformanilide, a nitrogen derivative, with
benzoyl chloride.

136

Wheeler.

^OAcr

This was confirmed by the fact that benzimidoethyl ester
gave ethylbenzamide when heated with ethyl iodide. We
stated that we hoped to reserve the further examination of
this rearrangement for this laboratory.

On the publication of these results Professor Knorr called
our attention to his work along similar lines in the case of the
cycloimido esters. He had previously shown that the oxygen
esters of the a-quinolones" are converted by methyl iodide
" langsam schon in der Kalte, rasch und vollstandig in der
Warme, in die Stickstoff-Methylester. " Thus, ethoxyquino-
line is converted into methylquinolone :

+ ICH3 = IC,H, +

OC,H«

NCH.

He also found that the oxygen meth^^ and ethyl esters of
oxy-;^-lepidine behaved in a similar manner. He showed that
this reaction in the case of ^K-methoxyquinaldine" takes place
first by addition ; and that this intermediate product then
when heated to 200" gives the nitrogen derivative. Again,
along with E. Fertig,' he found that tf-phen5d-7-methoxy-
quinoline was converted directl}' into the isomeric derivative
with methyl iodide, and finally he stated : " Ich hoffe bald
weitere Mittheilung machen zu konnen, ob sich ganz allge-
mein die Imido;:ther R'N : CE."OR"' durch Jodmethyl in
Amide secundarer Basen, CH3R'NCR"0 iiberfiihren lassen."
In view, however, of the work already done in this labora-
tory, and, since I informed Professor Knorr of my desire to
publish the work of my students, which was finished at the
time our first publication appeared, Professor Knorr kindly
gave over the entire field to me.

1 Ber. d. chern. Ges., 30, 929.

2 Ibid., 30, 924, 926.

3 Ibid., 30, 937.

Rea rrangemen t of Im ido- esters . 137

I wish to take advantage of this occasion to thank him for
his kindness and also to refer to other work bearing on the
rearrangement of the imido esters.

In the 3-ear 1885 Ponomarew' found that by treating silver
cyanurate with alkyl iodides, at low temperatures, the 0x3^-
gen esters result, while at higher temperatures the nitrogen
esters are the chief products.

In 1886 Hofmann' showed that the ox5'gen methyl ester of
cyanuric acid is transformed into the nitrogen ester simply by
heating.

In 1 89 1 Andreocci^ found that when phenylpyrodiazolon or
phenylmethylpyrodiazolon is methylated, and then treated
with methyl iodide, similar results are obtained, and that the
oxygen methyl compounds, when heated to 200°, are also
transformed into the nitrogen compounds.

All the above are examples of the rearrangement of cyclo-
imido esters. The transformation of benzimidochlorethyl ester
into /?-chlorethylbenzamide, under the influence of heat alone,
as described by Gabriel and Neumann,^ is especially interest-
ing, and, outside of our work, this appears to be the only
known example of a rearrangement taking place in the acyclic
series."

In the c3'^cloimido ester series N- alkyl derivatives have fre-
quently been obtained from silver salts, but particularly at
higher temperatures. This has notably been the case in the
uric acid group in Fischer's investigations.*' Since, how-
ever, the silver salt of hydroxycaffein gives with ethyl iodide
chiefly ethoxycaffein, he concludes that the former substance
does not have the grouping — CO — NH, but — COH=N — .
In this case he also noticed the formation of some tetra-
methyluric acid.

1 Ber. d. chem. Ges., i8, 3271.

2 Ibid., 19, 2061.

3 Ibid., 24, R, 203.
^ Ibid., 25, 2383.

5 I wish to express my thanks to Professor Gabriel for calling my attention to
this work. In a private communication from Dr. Stieglitz the foliowing: was men-
tioned : " I intended calling your attention to Knorr's paper in 'he Berichte, 1897, pp.
929-933. At the time when this came out I was heating ethyl imidobenzoate in a
sealed tube at 100° with ethyl iodide, but did not go on with the action on account of
Knorr's reservation."

6 Ber. d. chem. Ges., 30, 550.

138 Wheeler.

We find that the imidoesters of Pinner react slowlj^ even at
ordinary temperatures with methyl and ethyl iodides giving
alkyl amides. In the case of the benzimido esters benzamide
and benzonitril invariably accompany the alkjd amide. In
the lower-boiling portions of the reaction-product the pres-
ence, in small amount, of a substance that gave off an amine
odor on distilling was also observed.

With isobutyl iodide the chief products were benzamide
and isobutylene :

C,HJ==C,H, + HI,
and C,H,C(NH)OC,H,+ HI = C,H,CO.NH, + C,HJ.

In general, however, the chief reaction of methyl and ethyl
iodides is as follows :

^NH /NHCH3

C,H,C^ + CH3I = CeH.C/ + C,H,I.

In the case of the action of ethyl iodide on benzimidoethyl
ester, diethylbenzamide was sought for, but no evidence of its
presence was observed.

Besides others there are, therefore, three principal reactions
that take place when the acyclic imidoesters are treated with
the lower alkyl iodides :

a. A transference of alkyl group from oxygen to nitrogen.

b. The formation of hydrogen iodide which with unaltered
imidoester gives a primary amide (benzamide).

c. A decomposition of the imidoester into nitril and alcohol.

Experiments with Benzimidoesters .^
Benzimidomethylester and methyl iodide readily react at ordi-
nary temperature. Thirty grams of the imidoester were al-
lowed to stand for a month with 16 grams of methyl iodide
(0.5 molecule) ; in a short time crystals separated, which
finally developed into well-crystallized, flattened prisms. This
material proved to be benzamide containing a small amount
of cyanphenin and it weighed 3.5 grams. The oil filtered
from this was distilled at 13-12 mm. pressure {A below).
For comparison, 20 grams of the ester were heated to about

1^ The imidoesters in the following experiments were all freshly distilled. Under
diminished pressure they boil unaltered without exception.

Rearrangement of Imido- esters. 139

100° for five and a half hours with i gram of methyl iodide.
On cooling, crystals separated but were not filtered off, the
whole being distilled at 9-12 mm. pressure when the follow-
ing fractions were obtained {B) :

A. B.

Grams. Grams.

(i) below 159" 3.4 (i) below 155° 2.9

(2) i59°-i69° 9-8 (2) i55°-i65° 7-9

(3) i69°-i74° II. 5 (3) i65°-i68° 7.7

The first portions, in both cases, consisted chiefly of benzo-
nitril.

The second portions did not solidify on standing or when
cooled in a freezing-mixture. When distilled at 760 mm,
pressure, 2-B, for example, began to boil at 276°, and a strong
odor of amine and benzonitril was given off. The material
had no constant boiling-point, but distilled steadily up to 291°,
when the distillation was stopped and the residue (the greater
portion) was cooled. It then solidified and, when crystal-
lized from a small amount of alcohol, gave colorless flattened
prisms melting at 82°. This material had all the properties of
methylbenzamide (see below).

The third fractions in both cases readily solidified and were
crystallized from water. 3-^ gave square tables of methyl-
benzamide, while 3--5, from which benzamide was not re-
moved by filtration, gave a mass of plates melting at 128°, i. e.,
benzamide.'

The products identified in these reactions are, therefore,
methylbenzamide, benzamide, benzonitril, and a trace of cyan-
phenin.

From the above it appears that the action of methyl iodide
on benzimidomethyl ester is the same at 100° as at ordinary
temperatures, and that a small amount of methyl iodide pro-
duces practically the same result in this reaction as a large
amount.

1 In describing benzimidomethyl ester (This Journal, 17, 398), the author stated
that this ester, on standing, deposits benzamide. It is now known that this result
■was due to the presence of methyl iodide since the pure ester prepared by Pinner's
method does not deposit benzamide on standing. Daius (J. Am. Chem. Soc, 21,
i65), in his work on the isoureas, quotes this supposed behavior in his comparisons.
Benzimidomethyl ester, when pure, is quite stable.

140 Wheeler.

Benzimidoethyl Ester and Ethyl Iodide. — In the previous
paper the ester was heated with ethyl iodide, while the follow-
ing is a description of the action at ordinary temperatures :
49 grams of the ester were mixed with 52 grams of ethyl
iodide and allowed to stand for a month. At the end of this
time 5.2 grams of beautifully crystallized cyanphenin separa-
ted. It melted sharply from 23o°-23i°. The filtrate from
this was distilled at 773 mm. pressure, when 51., grams of
crude ethyl iodide were recovered (below 185°). After the
ethyl iodide was over, the material began to distil at 185"
when, up to 278°, 2 grams of fishy-smelling oil were obtained,
mostly benzonitril. From 278°-293° 10.8 grams of oil were
collected, while from 293°-300° the remainder practically all
came over. This weighed 23.5 grams, and when crystallized
once from dilute alcohol it separated in small flattened prisms
and melted from 69°-7o°, this material being pure ethylbenz-
amide.

A search was made for diethylbenzamide in the portion
boiling from 278°-293°, it having been found that this sub-
stance boils at 282°. For this purpose the fraction was cooled
in a freezing-mixture, and considerable ethylbenzamide was
then removed by filtering. The filtrate, when distilled at 763
mm. pressure, gave a few drops of fishy-smelling oil below
200° ; then up to 290° no definite boiling-point was observed,
the mercury in the thermometer not stopping an instant at the
boiling-point of diethylbenzamide. From the lower-boiling
portion of this fraction benzonitril was obtained ; the higher
consisted mostly of benzamide.

The chief products of this reaction are, therefore, ethyl-
benzamide, benzamide, benzonitril, and cyanphenin.

Diethylbenzamide was prepared from 5 grams of diethyl-
amine by means of the Baumann-Schotten reaction. It was
obtained as a clear, colorless oil that became thick, but did
not solidify at —25°. It boiled from 282°-283° at 763 mm.
pressure, and agreed in properties with the products obtained
by Kallmann' and by Romburgh.^ It is less soluble in warm
water than in cold.

1 Ber. d. chem. Ges., 9, 846.

2 Recueil d. Travaux chim. d. Pays-Bas., 4, 387.

Rearrangement of Imido- esters. 141

An experiment to determine whether benzonitril, ethj'l
iodide, and eth}-! alcohol react under the above conditions
was performed as follows : 10.5 grams of benzonitril were
mixed with alcohol and ethyl iodide in molecular proportions
and the mixture heated from ioo°-ii5° for nine hours. On
opening the tube there was no pressure, and, on distilling at
about 10 mm. pressure, the entire material boiled from 71°-
72° (benzonitril), except a few drops of black tar which re-
mained in the residue. No benzamideor ethylbenzamidewas
formed.

Benzimidoisobtityl Ester and Methyl Iodide. — Thirty grams
of the ester were heated with a little over one molecular pro-
portion of methyl iodide from 8o°-ii5°for four hours. On
cooling, an oil was obtained containing some crystals in sus-
pension. They were filtered and consisted of cyanphenin
and benzamide (separated by boiling water) . The oil was
distilled at 765 mm. pressure, when the portion boiling below
160° was collected. It weighed 24 grams, while the calcula-
ted yield of isobutyl iodide is 31 grams. On redistilling, it
boiled mostly from I2i°-i2i°,5, and proved to be pure iso-
butyl iodide.

The residue boiling above 160° was then distilled at 18-19
mm. pressure, when three fractions were obtained : (i) 98°-
172° (benzonitril) ; (2) i']2°-i']']° ; (3) ij'j°-iS'j°. The last
portion readily solidified ; the second deposited crystals on
standing. On crystallizing the material from alcohol prisms
were obtained melting at 82°. Romburgh gives 78° as the
melting-point of methylbenzamide. That the material is
methylbenzamide is shown by its properties and the following
nitrogen determination :

Calculated for

CflHjNO. Found.

N 10.37 10.40

The most striking property of the alkylbenzamides is the
behavior of their saturated aqueous solutions. When these
are warmed they become turbid in consequence of the separa-
tion of the amides in the form of oils. This turbidity disap-
pears again on warming to boiling, and on again cooling, this
behavior is reversed.

142 Wheeler.

Benziniidoisobiityl Ester and Isobutyl Iodide, — Thirty grams
of the former were heated from i65°-i85° for several hours.
On cooling and opening the tube considerable inflammable
gas escaped. It was concluded from its odor that this was
isobutylene. On distilling, 21 grams of isobutyl iodide w^ere
recovered. The remaining material was distilled at 13 mm.
pressure, when benzonitril and benzamide were the chief
products. The higher-boiling portion was crystLilized from
water, when it melted from i26°-i27°, and a nitrogen deter-
mination gave :

Calculated for
CgHsCO.NHj. Found.

N 11-57 11.22

Isobutylbenzamide. — This was prepared from 6 grams of iso-
butj'lamine by the Baumann-Schotten method. The material
thus prepared boiled from i73°-i78° at 13 mm. pressure, and
at 3o8°-3i3°, with slight decomposition, at 760 mm. pressure.
The oil thus obtained solidified to a beautiful crystalline mass,
which was crystallized from alcohol with the aid of a freezing-
mixture. It then melted at from 57°-58°. A nitrogen deter-
mination gave :

Calculated for
CjjHjsNO. Found.

N 7.91 8.19

Isobutylbenzamide forms chisel-shaped prisms and is diffi-
cultly soluble in water and petroleum ether, readily in ether,
chloroform, and alcohol.

Beyiziniidoethyl ester and isobutyl iodide did not act smoothly.
The products obtained were benzamide, benzonitril, cyan-
phenin, ethyl and isobutjd benzamides, and a substance, in too
small amount for identification, which, after crystallization
from alcohol separated in colorless, stout crj^stals, which
melted at 192° with effervescence.

EXPERIMENTS WITH PHENYIvACETIMIDOESTERS.
By Treat B. Johnson.

Phenylacetimidomethyl Ester and Methyl Iodide. — ( i ) Twenty
grams of phenylacetimidomethyl ester were heated with 9.5
grams of methyl iodide (i molecule of ester to 0.5 molecule of
iodide) for an hour from 95°-i05°. The product was then di-

Rea rra nge7n en t of Im ido- esters. 1 43

luted with ether and the precipitated material filtered off.
This proved to be phenylacetamide, and weighed 2.2 grams.
The ether solution was evaporated and the oil distilled at 25-
28 mm. pressure. The first fraction was collected from 115°-
to 187°. This weighed 4.2 grams and consisted mostly of
phenylacetonitril. The second fraction was collected from
i87°-i97°. This weighed 6 grams and was crude methyl-
phenylacetamide containing phenylacetamide. On crystalliz-
ing it from benzene and ligroin it melted at 147°, and on re-
crystallizing it from water it melted from i54°-i55° (the melt-
ing-point of phenylacetamide). If, however, the higher-
boiling fractions are crystallized from alcohol b)^ means of a
freezing-mixture methylphenylacetamide is obtained.

(2) For comparison, 20 grams of phenylacetimidomethyl
ester were again heated, this time with only 0.6 gram of
methyl iodide for six hours to the same temperature as before.
The residue left by ether (phenylacetamide) weighed 2.7
grams. On distilling the remainder at 27 mm. pressure the
first fraction, boiling between iio°-i87°, weighed 4.8 grams ;
the second fraction, i87°-i97°, weighed 5.5 grams.

(3) In another experiment 30 grams of the ester were
heated with 14.2 grams of methyl iodide, for six hours, from
ioo°-iio°. In this case the phenylacetamide weighed 3.6
grams. The first fraction of the oil distilled at about 20 mm.
pressure, boiled at from iio°-i8o° (mostly iio°-i30°), and
weighed 8.4 grams ; the second fraction (i84°-i90° at 18 mm.
pressure) weighed 10.5 grams. This latter was combined
with the second fraction obtained in our second experiment
and redistilled at 19 mm. pressure, when the greater portion
boiled from 179°-! 84", leaving little or no residue. This dis-
tillate readily solidified and, when crystallized from alcohol,
finally melted from 54°-57° (the melting-point of methyl-
phenylacetamide is given by Taverne' as 58°) .

A nitrogen determination in this material gave :

Calculated for
CcHjCHjCONHCH,. Found.

N 9.39 9.14

The substance formed in chief amount in these reactions is,
therefore , methylphenylacetamide .

1 Recueil d. Travaux chim. d. Pays-Bas., i6, 35.

144 Wheeler.

In order to simplify the comparison, the above results are
given in the following table :

Grams of
ester taken.

Weight of
iodide.

Time.

Weight of

phenyl-

acetamide.

(*)

Weight of
Weight of second
first frac- fractions,
tions. Crude Crude
nitril. methyl amide.
{c) (a)

(l) 20

9-5

I hr.

2.2

4.2 6.0

(2) 20

0.6

6 hrs.

2.7

4.8 5-5

(3) 30

14.2

6 hrs.

3-6

8.4 10.5

From this it is evident that, in this rearrangement the same
result is obtained whether a little (0.6 gram) or a large
amount (9.5 grams) of alkyl iodide is used. The close agree-
ment of experiments (i) and (2) under widel)^ different condi-
tions suggest that there is some definite relation between the
three principal reactions mentioned in the introduction. The
columns {a, b, c) show roughly to what extent these three re-
actions take place. In estimating this, however, it must be
remembered that the total weight of phenylacetamide is low
according to column {b) ; that the weight of nitril includes
some phenyl- and some methylphenylacetamide ; and that
column («) represents a mixture of the latter two substances.

Phenylacetimidoethyl Ester and Ethyl Iodide. — Twenty grams
of the ester were heated from ioo°-io6° with 19. i grams of
iodide for six hours. On cooling, the tube contained a thick,
red oil, together with some plates. The contents of the tube
were extracted with ether, and the insoluble residue, after
being crystallized from water, melted from I53°-I54° ; this was
pure phenylacetamide. The ether was then evaporated and
the remaining oil was distilled at 13 mm. pressure. The first
fraction, collected below 178'', proved to be chiefly phenyl-
acetonitril. The second fraction, collected from i88°-i98° at
17 mm. pressure, was obtained as a thick oil which soon
solidified in a freezing-mixture. This, when crystallized
twice from water, separated in the form of colorless plates
melting from 73°-74°. A nitrogen determination shows that
this material is ethylphenylacetamide :

Calculated for
CoHsCH-iCONHC^Hs. Found.

N 8.58 8.45

Rea7'rangement of Imido-esters . 145

In this rearrangement, in certain cases, some high-boiling
material was formed, but this decomposition-product was not
examined.

(2) 34.8 grams of phenylacetimidoethyl ester were heated
with 33.3 grams of ethyl iodide (i molecule of ester to i mole-
cule of iodide) for six hours from 95°-io6°. The amount of
phenylacetamide then obtained, on proceeding as above,
weighed 2.5 grams, and the amount of crude ethylphenyl-
acetamide weighed 10.9 grams, the remainder being phenyl-
acetonitril and some high-boiling residue.

(3) In another experiment 20 grams of the ester were
heated to ioo°-iio°for six hours with 19. i grams of ethyl
iodide, when the amount of amide isolated weighed 1.3 grams,
and the amount of crude ethylamide weighed 5.2 grams.

In all of the above experiments the first fractions were
tested for unaltered imidoester by mixing a portion with ben-
zene, and passing in dry hydrogen chloride, when no precipi-
tate was produced ; hence in each case the imidoester had en-
tered into reaction completely,

EXPERIMENTS WITH FURIMIDOMETHYL ESTER, /"-TOLENYL-

IMIDOMETHYl, ESTER, AND /5-NAPHTHYLIMIDO-

ETHYI, ESTER.

By Munson D. Atwater.

Furimidomethyl ester, C^HjO.C/ , was easily obtained

\OCH3
from furyl cyanide by following the directions of Pinner' for
the preparation of the corresponding ethyl ester. It was ob-
tained as a clear, colorless oil of peculiar odor. When dis-
tilled at 8 mm. pressure it boiled from 52°-57°. Redistilled at
762 mm. pressure it boiled from 169°-! 72° ; and a nitrogen de-
termination gave the following result :

Calculated for

C6H7NO2. Found.

N II. 2 II. 4

Furijnidornethyl Ester and Methyl Iodide. — ( i )Nineteen grams
of the ester were heated for six hours at 100° with a little over
ID grams of methyl iodide. The product, a light-yellow oil,

1 Die Imidoather, p. 50.

146 Wheeler.

was distilled at 21 mm. pressure, when 12 grams of material,
boiling from i37°-i47°, was obtained. This was redistilled
at ordinary pressure and collected between 250°-253°. This
portion, on standing several days in a desiccator, deposited a
considerable crop of colorless, stout crystals, which, when
crystallized from ligroin, melted at 64°. A nitrogen deter-
mination gave :

Calculated for

CgH^NOj. Found.

N II. 2 II. 4

This material is, therefore, methylpyromucamide. The
corresponding ethylpyromucamide was found by Wallach' to
be an oil boiling at 258°.

(2) In another experiment 30 grams of the imidoester were
mixed with 17 grams of methyl iodide and allowed to stand
nineteen days. At the end of this time i gram of pyromuca-
mide had separated, melting at 140". The oil filtered from
this was distilled at 20 mm. pressure. The oil collected below
143° had the odor of the unaltered material, while the re-
maining portion, between i43°-i48°, solidified and proved to
be a mixture of pyromucamide and methylpyromucamide.

The behavior of this ester with methyl iodide is therefore
closely similar to that of the preceding.

p-Tolcnylimidomethyl Ester. — This ester was prepared from
/-tolunitril by Pinner's directions. It was obtained as a
clear, colorless oil, with an odor entirely different from that of
the nitril. It boiled at 105°. 5 at 10.5 mm. pressure. A nitro-
gen determination gave :

Calculated for

CjHijNO. Found.

N 9.39 9.48

p-Tolenylimidomethyl Ester and Methyl Iodide. — Twenty
grams of the ester were heated to 100° for four hours. A lit-
tle pressure was found on opening the tube, which was filled
with a yellow crystalline mass of material. On crystallizing
twice from water(?) this melted from i44°-i45° (the melting-
point of />-toluic methylamide is given by Gattermann and
Schmidt' as 143°). A nitrogen determination gave :

1 Ann. Chem. (Liebig), 214, 229.

2 Ibid., 344, 51.

Rearrangement of Imido-esters. 147

Calculated for
C9H11NO. Found.

N 9.39 9.36

p-Tolenylitnidomethyl Ester and Methyl Alcohol. — Fifteen
grams of the ester were heated with one molecular proportion
of methyl alcohol for six hours at from ioo°-iio°. As there
appeared to be no reaction, the mixture was heated at from
ioo°-i40° for six hours more, and finally at from 150°-: 75° for
some time. The material then had the odor of nitril, and it
was distilled at 13 mm, pressure, when, after the alcohol es-
caped, it all boiled from 95°-97° (the boiling-point of />-tolu-
nitril), except a very slight residue. This, crystallized from
water, melted at 159°, and was therefore /-toluic amide.
Under these conditions no rearrangement took place.

(3- N'aphthylimidoethyl Ester and Ethyl Iodide. — The ester was
prepared from /^-naphthonitril, Pinner's directions being fol-
lowed. It was found that it could be distilled under dimin-
ished pressure, but the record of its boiling-point is not at
present available to the writer. That it did not suffer decom-
position in this treatment is shown by the following nitrogen
determination :

Calculated for
CisHjjNO. Found.

N 7.0 7.4

The material thus prepared is a clear, colorless oil, and
quite stable. Twenty-four grams of this ester were heated
with 9.4 grams of ethyl iodide for six hours at 100°. On
cooling, the tube was found to contain a solid mass of yellow
material. It was treated with alcohol, which left behind a
small amount of white crystals which melted above 280°. The
soluble part, when crystallized from alcohol, melted con-
stantly at i29°-i3i°, and is undoubtedl}^ ethyl-yS-naphthamide,
but a nitrogen determination gave 8.1 per cent of nitrogen.
(Calculated for amide 8.2 per cent, for ethyl amide 7.0 per
cent.) The lack of sufficient pure material prevented a dupli-
cate analysis.

148 Wheeler.

EXPERIMENTS WITH SILVER SUCCINIMIDE AND BENZOYI,-

BENZIMIDOETHYL ESTER.

By Bayard Barnes.

Silver Sticcitmnide and Methyl Iodide. — It was shown by
Comstock and Wheeler' that if perfectly dry silver succini-
mide is treated with alkyl iodides at ordinary temperatures, and
especial care is taken to avoid moisture, oxygen esters can be
isolated. The formation of a small amount of tLe nitrogen
ester under these conditions was also observed, and it was re-
marked that ' ' If the nitrogen ether is formed by molecular
rearrangement from the oxygen ether that rearrangement
must take place in this case at ordinary temperature." This
we now know to be the case, since this rearrangement is the
chief reaction at high temperatures. For example : 27 grams
of the silver salt were heated with 22.8 grams of methyl iodide
for six hours at ioo\ The material was then extracted with
ether and distilled at 20 mm. pressure, when it boiled from
140^-155°. This readily solidified and, on crystallizing from
alcohol, it melted from 68°-7o°. A nitrogen determination
gave :

Calculated for

CsHtNOj. Found.

N 12.38 12.45

The material is therefore A^-methylsuccinimide. On ex-
tracting the silver residue with alcohol, and crystallizing the
extract from benzene, succinimide was obtained.

Silver Succinimide and Ethyl Iodide. — (i) Twenty-four
grams of the silver salt and 22.5 grams of ethyl iodide were
heated for twelve hours at 100°. As unaltered silver salt still
remained, 13.8 grams more iodide were added, and the whole
reheated six hours longer. The material was then extracted
with benzene and distilled at 20 mm. pressure. The first
fraction was collected between i22°-i32° ; the second from
132^-142^ ; while above 142° the material solidified in the de-
livery tube.

The first portion was a pale-yellow oil at ordinary tempera-
ture, but it solidified on cooling, and, on freezing out of ether,

^ This Journal, 13, .5*9.

Rearrangement of Iniido- esters. 149

it was obtained iu colorless crystals melting at 26" (the melt-
ing-point of A^-ethjdsuccinimide). The second fraction was
mixed with a little aniline, and the presence of the oxygen
ethyl ester established by the formation of crystals, which,
after purification by dissolving in hydrochloric acid and pre-
cipitating with ammonia, melted at 216°, this substance being
the " base" described by Comstock and Wheeler, which per-
haps may be called or-ketopyrrolidine-o^-phenylimide or
a-anilidopyrrolon according to whether it has the structure :

CH,CO\ CH,CO\

I >NH or I >N .

CH,C <; CH,C ^

The third fraction or residue was found to consist of suc-
cinimide.

(2) In another experiment 30 grams of the silver salt were
heated with 45 grams of ethyl iodide for ten hours at from
i5o°-i55°. The material was then extracted with dry chloro-
form and the extract distilled at about 20 mm.(?) pressure.
The portion boiling below 134° was redistilled at ordinary
pressure, when it nearly all came over at from 233^-235°
(A^-ethylsuccinimide boils from 234°-235°). A nitrogen de-
termination in this material gave :

Calculated for

C9H9NO2. Found.

N 11.02 10.70

It follows from the above that the oxygen ethers of succini-
mide undergo rearrangement at high temperatures with
methyl and ethyl iodides giving the isomeric nitrogen com-
pounds.

Benzoylbenziviido Ester and Ethyl Iodide. — As an example of
the behavior of the acylimido esters with ethyl iodide, we de-
scribe the following experiment. We were unable to discover
any evidence of a rearrangement taking place in this case.
This is probably due to the negative character of the acyl
ester rather than to a stereochemical interference depending
on the molecular magnitude of the =NR grouping. This
subject will be investigated later.

150 Higbee.

Twenty grams of benzoylbenzimidoethyl ester and 6 grams
of ethyl iodide were heated for eight hours at from iio''-i20°,
when the material was found to be unaltered. It was re-
heated for seven hours at from i20°-i50° with the same result.
Finally, when heated to 200° for six hours, it decomposed.
On opening the tube there was considerable pressure and a
strong odor of benzonitril. The material was shaken with
sodium carbonate and extracted with ether. The solution of
sodium carbonate extracted benzoic acid, and the ether took
up benzonitril and ethyl benzoate. The amount of benzoni-
tril obtained weighed 5.6 grams, while the calculated yield of
benzonitril for the following decomposition is 8 grams :

^NiCOCeHj
CeH^cf r I = C,H,CN + CeH,COOC,H,.

^jOC^H, i

It is our intention to continue the study of these rearrange-
ments in other series.

New Haven, Conn., June 27, 1899.

THE DOUBIvE HAUDES OF ANTIMONY WITH
ANIEINE AND THE TOEUIDINES.

By Howard H. Higbee.i

This investigation, like others in the series, was undertaken
for the purpose of testing the truth of the laws governing the
composition of double halides first pointed out by Professor
Remsen.^

The method of preparing the salts was to bring the halide
of the base together with the corresponding halide of anti-
mony, each constituent being previously dissolved in the cor-
responding halogen acid.

The results were found to be most satisfactory when each
solution was heated before mixing ; the base was then added
to the metallic chloride.

1 From the author's dissertation submitted to the Board of University Studies of
the Johns Hopkins University, June, 1896, for the degree of Doctor of Philosophy.
The investig-ation was undertaken at the suggestion of Professor Remsen and was
carried on under his guidance.

2 This Journal, ii, 291 ; and 14, 87.

Double Halides of A ntimony. 151

The plan adopted in making the mixtures was to add the
halide of the metal in gradually increasing molecular propor-
tions to I molecule of the halide of the base.

Since in no case the analyses of any of the mixtures indi-
cated that more than i mole:ule of the halide of the metal
had combined with i molecule of the halide of the base, mix-
tures were not made containing more than 3 molecules of the
halide of the metal to one molecule of the halide of the base.

Similar trials were then made in the other direction, i. e., i
molecule of the metallic halide was mixed with a gradually
increasing number of molecules of the halide of the organic
base in the ratios of 1:2, 1:3, 1:4, and 1:6, respectively.
The limit of double salt formation in this direction was con-
sidered reached, since in many cases the halide of the base
crystallized out even in mixtures of i 13, and in no case was
a salt found which contained more than 4 molecules of the
halide of the base to one of the antimony.

Every mixture made produced a double salt of some kind.
When the solutions were of a proper consistencj' the forma-
tion of the crystals was of a uniform character, and they were
easily obtained, as a rule, in that condition. The compounds
formed differed markedly in their powers of crystallization,
but as the formation of crystals with well-defined angles and
faces would require days and often weeks, no special attempt
was made to gather and study the stibstances crystallographic-
ally. Such investigation was further interfered with by the
fact that many of the substances rapidly underwent changes
which rendered them unfit for that kind of study.

A few notes, however, of a crystallographic character,
kindly furnished by Mr. A. C. Spencer, of the Geological
Department of this Universitj', will give an idea of the nature
of some of the substances in this respect.

As a rule, if the first crop of crystals was found to be uni-
form in appearance, they was subjected to chemical analysis,
the determination of the halogen and the antimony being con-
sidered suf&cient for the identification of the substance.

The results of the analyses of the compound formed from
each mixture are placed in a table at the end of the descrip-
tion of these compounds.

152 Higbee.

Under each mixture is placed the results of the analysis of
the compound obtained from that mixture, and in the smaller
table is found the summary of the results of the analyses
grouped under the formula of those compounds which the
analyses seem to indicate have been formed.

The estimation of antimony was effected as follows : About
0.3 gram of the dried salt was weighed off, and after dissolv-
ing in a few cc. of a strong solution of tartaric acid, the whole
was considerably diluted with water and heated to boiling.
The solution was then acidified with sulphuric acid and a cur-
rent of washed hydrogen sulphide passed into the solution for
some time. When the antimony had been completely pre-
cipitated the liquid was heated for some time to drive off the
hydrogen sulphide. The precipitate was then collected in a
porcelain Gooch filter and washed successively with water,
alcohol, ether, and carbon disulphide. The crucible was
then dried in a hot-air bath, filled with carbon dioxide, grad-
ually heated to 250°, and kept at that temperature for about
an hour.

Experiments with Aniline Hydrochlonde arid Antimony Tri-
chloride.

The account of the experiments with aniline hydrochloride
and antimony trichloride will now be taken up in detail.

From mixture No. i (one part of the base to one of the
metallic chloride), there crystallized out a colorless salt in
thick irregular prisms, which on analysis gave results for
chlorine and antimony, as recorded in Column i of Table I.

On comparing these results with the theoretical values
which ought to be obtained if a compound called for by the
one at the head of Column i had been formed, no agreement
between these values was found, but as these experimental
results did compare with the theoretical percentages of the
compound heading Column 5, it was concluded that a com-
pound was formed, having the composition expressed by the
formula (C.H,.NH,.HCl),.SbCl3.H,0, which may be called
trianiline chlorantimonite.

Double Halides of Antimony. 153

Properties of the Compound,

This substance crystallizes in thick, colorless, monoclinic
prisms, having the appearance shown in Fig. i.

The action of a number of solvents
was tried, and it was found to dissolve
quite readily even in all the dilute min-
eral acids as well as in a number of
organic acids in concentrated form; e.g.,
tartaric and acetic acids. It required
rather strong ethyl and methyl alcohol
to effect solution.

Water or dilute alcohol precipitated
a white antiraonyl compound.

On boiling a solution of the salt the
odor of nitrophenol was given off.

On gently heating the dry substance
in an open tube it was rapidly decomposed, hydrochloric acid
being given off.

After exposure to the air for several days the substance ac-
quired an opaque greenish appearance. On keeping speci-
mens for several months no further change in appearance
seemed to occur.

The results of an analysis of mixture No. 2, in which the
constituents were combined in the proportion of i molecule of
aniline hydrochloride to 2 molecules of antimony trichloride,
pointed to a compound of the formula

C,H,.NH,.HCl.SbCl3.H,0.

• Monaniline chlorantimonite crystallized out in long, thin,
colorless plates. In general it was found to be similar to the
first salt described.

Analyses of mixture No. 3 showed that monaniline chloran-
timonite was again formed.

Mixtures 4, 5, and 7, each in turn, produced one and
the same compound ; vi2., trianiline chlorantimonite, the one
first described above.

The results recorded include the analyses of both first and
second crops, but in no case were the second crops found dif-
ferent from the first.

154

Higbee.

Table I. — Salts of Aniline Hydrochloride and Antimony Tri-
chloride.
I. II. III. IV. V.

d

C

0

0

d

K

W

W"

w

w

N

m

m

A

^

G

0

0

Si

0

0

.0

0

^

0

i.SbC

G

02

Si

XT.

CC

w.

c«

-^

-— ^

— s

^^

^

^

^

'y^

^

^

0

0 n

0

0

a

0

W

w t

i,_

w

15

5

2

w

w

K

w

w

w

w

w

£

W

d

d t

J

d

u

d

a

d

d

0

Theor.

Sb

33-70

32.08

41.20

39-96

44-49

4-53

24.70

23.83 19.5

[ 18.95

CI

39.88

37-97

42.66

41.38

43.88

42.92

36.56

35.25 34.63 33.65

Exp.

Sb

19.18

...

—

—

32.71

19.01

—

19.05

CI

33-31

37-54

.

..

—

33.54

Sb

19-93

19.74

34.11

34-65

32.62

32

66

19.50

19.28

19.18

CI

33-69

37-36

37-47

38.08

38

13

33.63

33.77

33.50

Sb

33.9 c ....

—

19.10

CI

37.46

....

..

—

33.24

Sb

•

..

19.08

CI

.

..

—

33.29

Summary of Aniline Hydrochloride and Antimony Trichloride

Salts.

I. V.

[C6H5.NH2.HCl.SbCl3.H2O.] [(C6H5.NH2.HCl)3SbCl3.H20.]

Sb.

CI.

Sb.

CI.

Theor.

32.08

37-97

18.95

33-65

Exp.

32.71

38.08

19.05

33

54

32.62

38.13

19.18

33

50

32.66

37-54

19.10

33

24

33.51

37-36

19.08

33

29

33-90

37-47

19.01

ZZ

63

....

37.38

19.50

33

77

....

37-46

19.28

33

31

....

....

19.18

33

23

....

....

19.74

33

69

....

....

19-93

33

33

....

....

18.88

Double Halides of Antimony. 155

Experiments with 0- Toluidine Hydrochloride and Antimony

Trichloride.

Experiments were next undertaken in the i?-toluidine series,
the line of work being carried out in a manner similar to that
followed in the experiments with aniline.

The analj'ses of the compounds resulting from the several
mixtures in this series point to the existence of only one com-
pound, z'z^., di-^-toluidine chlorantimonite, having the compo-
sition expressed by the formula (C,H,.CH,.NH,.HCl),.SbCl,.

A large quantity of colorless crystals separated out from
mixture No. 5, which, when dissolved and treated with hy-
drogen sulphide, gave no reaction for antimony.

The substance was the halide of the base. On pouring off
the mother-liquor from these crystals, a compound of a differ-
ent form at once separated out, which proved to be the double
salt above mentioned. This substance, as usually formed,
did not differ much in appearance from the aniline salts
already described.

When allowed to form rapidly the tendency of both the ani-
line and all the toluidine chlorantimony salts is to crystallize
out in beautiful sheaf-like masses with a satin luster.

The analytical results of the study of this series are placed
in Table II :

156 Higbee.

Table II. — Salts of o-Toluidine Hydrochloride and Antimony

Trichloride.
I. II. III. IV. V. VI.

d

d

d

0

d

W

W

w

W

W

w

t;

r^

r^

ro

rn

m

^

^

0

0

0

0=

0

0
55

0

05

02

xn

tn

Xfi

xn

tn

^--

^

'-.-

■ — .

^^

^

^

^

^

^

u

0

0

0

o

0

0

0

ffi

K

w

^

W

15.

w
:?

K
Z

w
z

X

z_

w

w

w

W

K

W

0

a

a

q

a

q

q

q

q

^

-r

ffl

■^

W

M

M

W

w

W

ffi

w

W

d

d

d

d

d

d

d

d

d

d

d

7%^or.

Sb 32.43

40.23

..

..

23.36

22.57

18.26

...

CI 38.38

..

—

• •

34.56

33.39

32.42

...

Exp.

Sb 23.96

25.03

••

25.60

23.65

24.06

CI 34.48

• •

34.83

34.97

34.24

—

34-40

25-'

Sb 23.92

24.99

25.23

23.73

24.14

• •

CI 34.52

••

34.84

••

34.85

••

34.41

34.87

...

Summary of 0- Toluidine and Antimony Trichloride Salts

IV.

(C6H.

,.CH3NH2.HCl)2SbCl3.)

Sb.

Cl.

Theor.

23-36

34-56

Exp.

2

3.65

2;

3.96

34-24

34-

87

23-73

2.

3-92

34-41

34.

.83

. ...

34-48

34-

84

. ...

'

, ...

34-52

34-97

• • • •

. ...

34.40

34.

.85

Experiments with m,- Toluidine Hydrochloride and Antimony

Trichloride.

As in the case of experiments with (?-toluidine, the hydro-
chloride of the w-base was mixed in various proportions with
the chloride of antimony. On an examination of the com-
pounds obtained from each of the seven mixtures made, only

Double Halides of Antimony.

157

two substances were found which proved to be different from
each other. Each of the seven mixtures, except the third,
gave a compound having the formula

(C«H,.CH,.NH,HCl)3.SbCl„

which should be named tri-wz-toluidine chlorantimonite.

This substance always cr\'stallized in thin orthorhombic
tablets in the form of radiating groups, and perfectly trans-
parent and colorless.

Following is a brief crystallographic account of one of the
crystals examined :

P ^--^F^^-^

^^ ^ ^ Orthorhombic.

C ^ basal plane.

p = brachypinacoids.

S = macrodomes.

Mixture No. 3 gave a compound which
on analysis pointed to a substance whose composition should
be expressed by the formula

(C„H,.CH,.NH,.HCl),.SbCl3.H,0,

di-w-toluidine chlorantimonite.

An analysis of one sample of the substance pointed to the
previous substance without water of crystallization. The
only form in which this compound was obtained was in fine
granular crystals.

The results of experiments with ?«-toluidine compounds are
recorded in Table III.

C
a

-<-

Fig. 2.

158

Higbee.

Table III. — Salts of m-Toluidine Hydrochloride and Antimony

Trichloride.

I.

II

III.

IV.

V.

VI.

VII.

d

d

d

d

d

w

w

w

w

ffi

»

f^.

r*^

m

rh

.-?

r^

(^

rn

to

0

X3

r^

0
^

m

0

^

0

to

to

'J

0

to

C/3

CO

w.

C/}

cc

w.

, %

-— s

- — s

^— s

, s

f— «

1— <

.—1

"■ — ^

t— 1

I—*

a

a

tj

tJ

0

(J

0

a

0

W

0

ffi

K

w

W

w

K

2^

2

w
^

a

0

0

ffi

ffi

ffi

ffi

ffi

W

K

w

w

w

W

a

a

a

a

0

a

0

d

a

CJ

u

u

Theor.

Sb 32.43

40.23

—

23.36

22.57

18.26

..

—

CI 38.38

..

—

..

—

••

34.56

33.39 32.42

• •

—

—

Exp.

Sb 19.87

18.69

20.65

23.11

22

56

18.76

18.82

• •

18.65

17.97

CI 32.51

32.58

• •

33.19 34.08

33

14

32.35

32.25

32.65

3T.97

Sb 19.73

18.66

20.71

22

51

18.78

18.79

18.61

—

CI 32.41

r" _-

32.43

.X ...

'7"

33.28
- 7. . • J-.

T

33-43

7-.. J

7. 7-....

22.19 32.69

-7. 7 /I .

* •

32.29

T--- •

Summary of m-Toluidine Hydrochloride and Antimony Tri-
chloride Salts.

V.

VI.

[(C6H4.CH3.NH2.HCl)3SbCl3.] [(C6H4.CH3.NH2.HCl)2SbCl3.H20.]

Sb.

Cl.

Sb.

Cl.

Theor. 18.61

32.42

22.57

33-39

Exp. 18.61 18.78

32.29 32.41

22.56

33-14

18.65 18.69

32.35 32.58

22.51

33-43

18.82 18.66

32.25 32.43

23.11

34.08

18.79 17.97

32.69 32.51

....

33-19

18.76 19.03

32.35 31-97

....

33.28

32.19 32.31

....

....

Experiments with p-Toluidine Hydrochloride and Antimony

Trichloride .

The compounds obtained in this group are di-^^-toluidine
chlorantimonite, (C,H,.CH,.NH,.HCl),SbCl3.^H,0, and tri>
toluidine chlorantimonite, (C,H,.CH,.NH,.HCl),SbCl,.H,0.

Double Halides of Antimony.

159

Mixtures i, 2, 3, and 4 produced the second of the above
compounds, while the first was formed only by mixture 5.
The tri-compound forms in colorless granular crystals, while
the di-compound is formed in long, colorless, silky needles.
Neither of these compounds seems to undergo any change on
being kept for months.

The analytical results are recorded in the following table
and summary :

Table IV. — Salts of p-Toluidine Hydrochloride and Antimony

Trichloride.

II.

III.

IV.

d

d

q

d

d

w

w

w

w

n

N

(^

rn

l-H^

.-h'

1-H^

,_lp

"^

^

^

•^

a

a

a

0

1-H

f— »'

.—1

.-H

t— 1

»— «

J2

X!

.Q

.Q

a

0

0

0

0

0

I/J

^

tn

tfi

.c

.0

.Q

.n

.Q

.Q

w.

IZ!

^

c/2

S

tfi

^^

^ s

^-^

^ s

0

0

0

0

0

0

0

W

a

0

W

a

K

W

W

w

2

ffi

K

W

w

w

0

0

u

q

q

q

q

q

K

ffi

ffi

M

ffi

d

d

d

d

0

0

d

d

d

d

Theor.

Sb

32.43

40.23

—

23.36

22.97

18.26

17.77

CI

38.38

• •

34.56

33-95

32.42

31.55

Exp.

Sb

23.68

23.40

• •

23.68

—

22.09

18.27

CI

Sb

33.52
23.58

33.66
23.50

33.16
24.03

• ■ • •

33.13
22.61

31.54
18.21

CI

33-49

33.38

• •

33.08

—

33-10

28.14

Sb

....

..

—

....

18.27

CI

33.10

—

..

....

....

31.46

Sb

—

..

....

....

18.11

CI

—

—

—

31.55

i6o

Higbee.

Summary of p- Toluidine Hydrochloride and Antimony Trichlo-
ride Salts,
IV. V.

(C6H4.CH3.NH2.HCl)2.SbCl3.m20. (C6H4.CH3.NH2.HCl)3.SbCl.H=0.
Sb. CI. Sb. CI.

Theor. 22.97 33-95 17-77 3i-55

Exp. 23.68 23.50 33.52 33.66 18.27 18.27 31.54 31.55

23.58 23.68 33.49 33.38 18.21 18. II 31.46

23.4024.03

Experiments with Aniline Hydrobromide and Antimony Tri-

bromide.
The following series of mixtures of the above substances
were made in hydrobromic acid solution: 1:1, 1:2, 1:3,
2:1,3:1,4:1, and 6:1.

In beaker No. i there was formed a copious crop of fine,
light-yellow needles. In No. 2 there was a scant crop of two
kinds of crystals, one kind being thin, flat, rectangular plates;
the other yellow, granular crystals. Mixture 3 gave yellow
needles, similar in appearance to those in No i. In beaker 4
was formed a small crop of yellow needles along with larger
yellow, granular crystals. A copious crop of light-yellow,
scaly crystals was found in beaker 5. In No.
6 appeared a copious crop of yellow, granular
crystals. A copious crop of irregular, flat, thick,
whitish-yellow plates formed in beaker 7.

As in each case, the crystals had formed too
}) quickly to be well defined and uniform, all the
crops were redissolved, the solutions somewhat
diluted, and again set aside to crystallize out.
The next series of crystals were generally of
better form. Salts from beakers i, 2, 3, 4, and
Fig- 3- 5 crystallized out in centimeter-long, canary-yel-

low, lath-shaped crystals of the orthorhombic system and of
the form shown in the accompanying figure.

The cleavage is parallel to a. The crystals also showed
parallel extinction in polarized light.

A chemical analysis of each of these five crops resulted in
pointing to only one chemical compound, which is repre-
sented by the formula (C,H,.NH,.HBr),SbBr3, and receives
the name dianiline bromantimonite.

<^

a

Double Halides of Antimony.

i6i

m

a

c

Fig. 4.

ta

It is of a canary-yellow color and translucent, stable in the
air, undergoing no perceptible change on being kept for
several months. The analyses showing its composition are
given in the following table :

Mixtures 6 and 7 produced substances, which though of the
same yellow color, differed markedly in their crystal habit. This
will be best indicated by the figure. Cleavage is parallel to
a and perfect. Habit tabular and perpendicular
to a. Orthorhombic system.

a ^ brachypinacoid.

c = basal plane.

p =. macropinacoids.

m =^ macroprisms.

An analysis of this salt showed it to have an
unusual composition, there being 4 molecules of
the halide of the base combined with i molecule
of the halide of antimony.

Its composition is expressed by the formula (CjHj,.NHj.
HBr)^SbBr,.H,0, and the compound receives the name
tetraniline bromantimonite.

It was found impossible to determine the water of crystalli-
zation by exposure of the substance over sulphuric acid, as
after a short treatment of this kind dense fumes of hydrobro-
mic acid were given off.

On preserving crystals of the substance for some time they
gradually became opaque.

The results of the above experiments are recorded in
Table V :

l62

Higbee.

Table V. — Salts of Aniline Hydrobromide and Antimony Tri-

broviide.

I. II. III. IV. V. VI. VII.

P3
jO
Xfi

«

%_

W
o

Theor.

Sb 22.47

Br 59.93

Exp.

Sb 16.74

Br 56-75

Sb ....

Br ....

Sb ....

Br ....

pq

PQ

PQ

pq

.Q

.Q

.Q

^

m

tfj

Cfi

a^

)-(

Vh

^

u

m

P3

PQ

PQ

53

W

K

w

W

W

w

K

^

:z;

^;

z

tj

26.85
62.64

17-45
57-05
11-59
54.80

i xj

28.71
63-79

16.53
56.02
16.34
5S.82

16.95 16.53 13-60
56.49 55.10 54.42

16.77
56-56

16.40
56.39

11.36 II. 17 8.55
53.03 52.14 51.28

11.26 11.06

52.26 52.16

11.24

.... 51.97

11.07

52.22

Summary of Aniline Hydrobromide and Antim-ony Tribromide

Salts.

IV. VI.

(C6Hs.NH2.HBr)2SbBr3. (C6H5.NH2.HBr)4SbBr3.H20.

Sb.

Br.

Sb.

Br.

Theor.

16-95

56.49

II. 17

52.14

Exp.

16.74

56.75

11.06

52.16

16-45

57-05

11.24

51-97

16.53

56.02

11.07

52.12

16.34

55-82

11.26

52.26

16.77

56.56

....

....

16.40

56.39

....

....

Experiments with o-Tohddine Hydrobromide and Antimony

Tribromide.
From the seven mixtures which were made, judging by the
appearance of the crystals formed, only one kind of compound
seemed to be produced. The crystals of this substance had
the same general appearance in each beaker, being of a light-
yellow color. The crystallizing force of the substance seemed

Double Halides of Antimony. 163

to be weaker than that of any of the compounds previously-
analyzed.

Small, short, blunt prisms crystallized out, both as first and
second crops, from the same mixture.

Determinations of antimony and bromine led to the conclu-
sion that tri-i7-toluidine bromantimonite (CjH^.CH,.NH,.
HBr),SbBr,, was the only compound formed from the con-
stituents employed.

Table VI. — Salts of o-Toluidine Hydrobromide and Antimony Tribromide.

I. II. III. IV. V. VI. VII.

o^ o^ 6^ 6^ do

9 w w w w w a

*^ ^^ -^ ,~~ .'^ u u \^ u iITvh »-iiir

SS S'S 33 ^^, ^^ ^^ ^ ^

Vi Vx ux m ui tn ^ ^ ^ ^ ^ ^ ^ ^

WW WWWW---- ". . ."

w w w w w w I g 5 5 t S i 5
WW w" W W W ?1 ?1 F, ?1 <^, ?^> ?? w"
w^ w"" w"" w^ w' w ^ ^ ^ '^ ^ ^ ^ w

Sb 21.89 21.20 26.43 25.92 28.39 27.99 16.30 15.91 12.98 12.74 10.80 10.62 8.06 7.97

Br 58.39 ....61.56 ....63.09 •••• 54-35 53-05 51-95 50.95 50.36 49-56

£xp.

Sb 13.37 12.80 12.67 12.87 12.78 12.86 ...

Br 50.63 .... 51.70 .-.. 50.62 .... 50.76 .... 51.71 .... 51.26 .... 51.41 ...
Sb

Br 50.57 51-84 •••• 51.57 51-51 •••

Sb 13.17

Br 51.07

Summary of o-Toluidine Hydrobromide and Antimo^iy Tribro-
viide Salts.

V.
(C6H4. CH3.NH2. HBr)3SbBr3,

Sb. Br.

Theor. 12.98 51-95

Exp. 13.17 12.87 51-70 51-70

13.37 12.78 51.84 51.26

12.80 12.86 51-07 51-51

12.67 .... 51.57 51.41

164 Higbee.

Experiments with m-Toluidine Hydrobromide and Antimony

Tribromide.

Out of the seven combinations made only one com-
pound was found. This substance crystallized out in each
beaker in long, very pale-yellow, silky needles. The air-
dried salt was more opaque and yellower than when seen in
the mother-liquor. An analysis of the result of each mixture
pointed to one compound only, and this has the composition
expressed by the formula (CeH^.CH^.NH^.HBrj^SbBr,, and
called di-w-toluidine bromantimonite.

Table VII. — Salts ofm-Tohddine Hydrobromide and Antimony

Tribromide.

I. II. III. IV. V. VI. VII.

P3

m

^

.0

xn

xn

W A

Cq P5 M

WWW

WWW
^ ^ ^.

WWW
o q a

W ^ "^

o o 6 '^^ 6

w w w ^ . w

u

m

m
£

XfX

C/2

PQ

/3

PQ

.Q

.Q

^

Ui

xn

CC

Cfi

.0

tfl

xn

m

^

^

j^

J^

^

^

yj

u

u

^

>-c

ii

tH

u

V-c

^

CQ

M

pq

M

P3

P3

IH

P5

w

w

W

W

^

W

^

W

W

P5
W

w

w

w

W

W

W

w

w

w

w

w

q

w

w

q

w

W

W

W

w

w

w"

q

q

q

a

q

0

q

W
0

W

W
0

W

W

W

w

W

w

W

0

a

0

a

0

0

a

Sb 21.89 21.20 .. 26.43 •• 28.39 •• 16.30 .. 12.98 .. 10.80 .. 8.06

Br 58.39 56.53 .. 61.56 .. 63.09 .. 54.35 .. 51.95 .. 50.36

Exp.

Sb 15.89 15.65 .. 16.66 16.45 .. 15.96

Br 54.27 54.49 •• 54-27 •• 54-38 •• 54-03 •• 54-93 •• 54-20

Sb •• 16.31

Br 54.86 54.49 •• 53-93 54-25

Double Halides of Antimony. 165

Summary of m-Toluidine Hydrobrotnide and Antimony Tribro-

mide Salts.

IV.

( C6H4. CH3. NH2. HBr ) sSbBrj.

Sb.

Br.

Theor.

I

6.30

54-35

Exp.

16.31

15-96

54-49

54.20

16.66

15-89

54.86

54-25

16.45

15-65

54-38

54.27

....

....

54-03

54-27

....

....

53-93

54.93

....

....

54.49

....

Experiments with p-Toluidine Hydrobromide and Antimony

Tribromide.

The mixtures of the constituents were made in the usual
waj' in hydrobromic acid solution. Mixtures i, 2, 4, 5, and
7 all gave crops of silver-white needles.

Repeated attempts were made to get a salt from mixture
No. 6, but it was possible only to obtain the /»-toluidine hy-
drobromide from the solution.

Mixture No. 3 gave a crop of very small lemon-yellow
plates.

Owing to the ease with which the white salts give up or
take up water of crystallization it was difl&cult to get sharp
analytical data. The analyses of all the salts obtained seem
to point to the existence of three different compounds, and
one of them also with water of crystallization. They were as
follows : Di-/-toluidine bromantimonite (CcH^.CHj.NH^.
HBr),.SbBr3; the same compound with i molecule of water
of crystallization (C,H,.CH3.NH,.HBr),.SbBr,.HO ; tri-/-
toluidine bromantimonite, (C6H,.CH3.NH,.HBr)3.SbBr3 ; and
tetra-/)-toluidine bromantimonite, (C,H,.CH,.NH,.HBr),.
SbBr3. In dry air these compounds are canary-yellow, but if
exposed to the air on a damp day they change to snow-white.
The compound which crystallized out from mixture 3, in the
form of small plates, seems to be quite stable as to its color —
it remains yellow constantly.

The yellow color can be restored in all three compounds by
gently heating a portion on a piece of platinum foil.

1 66

Higbee.

The analyses of the compounds are tabulated in the usual
manner in Table VIII.

Table VIII. — Salts of p-Toluidine Hydrobromide and Antimony Tri-

bromide.
I. II. III. IV. V. VI. VII.

0

W

d

d

d

d

d

d

^

W

w

K

w

W

»^

u

--^

jz

u

u

u

tT

u

l-c

u

\-i

A

A

P3

W

)h

Vh

w

P3

fp

M

W

pq

P5

pq

w

w

^

.0

PQ

n

^

^

-Q

^

^

.0

^

^

^

^

tn

tn

^

tS

CO

to

CO

to

tfX

CO

^

^

tfx

t/2

^ V

, s

t/i

CO

.. — ^

■ — ■

j^~^

,^^

,^~^

^ — ^

i-t

w

u

;-•

Vh

i-<

i-

;h

Vh

»-■

u

u

w

P5

V.

;-i

M

P3

P3

PQ

PQ

pq

P5

PQ

w

W

P3

W

W

W

w

W

X

^

w

W

W

w

w

w

w

w

W

w

w

^

^

^

^

:^

;^_

z

^

15

^.

0

w

w"

0

0

w

w

w

w

K

W

W

w

a

0

u

q

q

q

q

q

q

q

•fl-

4

■^

4

"*

w

W

W

w

w

w

W

W

W

W

W

W

W

0

0

0

0

a

0

0

0

0

0

a

d

0

0

Theor.

Sb

21.89

21.20

26.43

25.92

28.39

27.99

16.30

15-91

12.98

12.74

10.80

10.62

8.06

7.9/

Br 58.39

—

61.56

63.09

54.35

53-05 51-95 50-95 50-36 49-56

...

Exp.

Sb

—

16.04

—

—

12.59

15-09

Br

—

52.73

54-78

—

. ..

51.45

52.90

Sb

15-73

—

10.85

Br

53-55

54-72

—

51-49

52.58

Sb

10.65

Br

53-94

54-54

49-83

Sb

—

Br

54-15

50.00

Sb

—

Br

53-7°

—

Summary of p- Toluidine Hydrobromide and Anti'mony Tri-

brom,ide Salts.

IV.

V.

VI.

Sb.

Br.

Sb.

Theor.
Exp.

16.30 54.35
53-94
53-55
54-15
53.70
54.78
54.72
54-54

15
16

15

Br.
91 53.05
04 52.73

73 52-52
52-48
52-90
52.58

Sb.
12
12

Br.
98 51.95

59 51.45

51-49

Sb.

Br.

ID
ID
ID

80 50
85 50
65 49

36
GO

83

Dou ble Halides of An tim ony. 167

On exposing the compound (which on analysis showed the
presence of water of crystallization) in the desiccator over
concentrated sulphuric acid, there was a constant loss of
weight, due to the evolution of hydrobromic acid, presuma-
bly.

Experiments with Aniline Hydriodide and Antimony Triiodide.

Study in this series was begun with the aniline salt. Some
difficulty was experienced here, since it was necessary to pre-
pare hydriodic acid only in such quantities as would be im-
mediately needed, owing to its rapid decomposition. It was
also difficult to avoid the separation of free iodine when heat-
ing the mixtures.

The mixtures of the aniline and antimony halides were
made up in the usual proportions hitherto emploj^ed.

A crop of finely divided, granular, scarlet crystals separa-
ted from mixture No. i. On drying, these seemed to undergo
no change. A determination of antimony and iodine clearly
pointed to the existence of a compound whose composition is
expressed by the formula CjHj.NH^.HI.Sblj, monaniline
iodantimonite.

Out of mixture No. 2 small, almost microscopic, scarlet
octahedra with modified edges crystallized out. An analysis
of these revealed no new compound.

Crystals from mixture 3, again in the form of modified and
twinned octahedra, proved on analysis to be identical with
the first compound discovered in this series.

Mixtures 4 and 6 yielded nothing new in the way of double
salts. Mixture No. 5, on the other hand, yielded a beautiful
crop of fine carmine needles, which on analysis proved to be
a combination not yet met with in the present investigation.
The compound is composed of 3 molecules of aniline hydri-
odide and 2 molecules of antimony triiodide, expressed by the
formula (CjH5.NH5HI)3(Sbl3)2, trianiline diiodantimonite.

The last mixture examined was that in which the ratio of
the constituents was 6:1. A new compound seemed to be
formed here. The mixture from which the compound was
finally obtained yielded at first only a large crop of the halide
of the base. On evaporating the mother-liquor, a crop of

i68

Higbee.

uniform golden-yellow plates was obtained. These were
dried and tested for antimony. It was found to be present in
considerable quantity. As soon as the crystals were drained
off they began to undergo change in color from golden-yellow
to orange-red. When dry they were analyzed and gave re-
sults pointing to the formula (C6H,.NH,.HI),Sbl3, tetraniline
iodantimonite.

The analytical results of the study of this series are given
in Table IX.

Table IX. — Aniline Hydriodide and Antimony Triiodide.

I. II. III. IV. V. Va. VI. VII.

^

3

3

3

t>2

1

1

m

J5.

CO

•^

;!;■

^

'^

^

S

w

s

K

W

W

W

s

N

N

W

K

ffi

M

w

III

Z

:z;

2

Z

z

w

M

w

ffi

ffi

w

W

w

a

0

0

u

a

o

tj

d

• — '

Theor.

Sb 16.62 16.21

19.62

....

10.31

14.41

8.66

—

I 70.36 68.64

72.69

73.08

67.34

65.46

68.64

64.19

62.56

Exp.

Sb 16.78 ....

—

14.52

—

8.71

I 70.15

70.30

70.14

70.84

68.23

70.29

64.32

Sb 16.80

14.48

—

8.24

I 70.44

70.39

70.10

70.08

68.31

69.99

64.31

Sb ....

—

—

14.14

I

68.35

...

64.47

Sb ....

—

14.34

...

I

....

68.75

....

Summary of Aniline Hydriodide

and Antimo^

iy Triiodide

Salts.

I.

Va.

VI.

Sb.

]

Sb. I

Sb.

I.

Theor. 16.62

70.36

14.41 68

64

8.66

64.19

Exp. 16.78

70-15

70.10

14.52 68

23

8.71

64.32

16.80

70.44

70.84

14

.48 68

31

8.24

64.31

....

70.31

70.08

14

14 68

35

64.47

....

70.39

69.99

14.34 68

75

....

.

...

70.14

70.29

•

...

••

....

Double Halides of Antimony. 169

Experiments with 0- Toluidine Hydriodide and Antimony Tri-

iodide.

The usual experiments were made with the above ingre-
dients and no difl&culty was experienced in obtaining well-
characterized products in each experiment. The double salts
which crystallized out from each of the first three mixtures had
the same general appearance, consisting of short blunt needles
of a brick-red color. Analyses of the three sets of crystals
pointed to one and the same compound, containing i molecule
of each of the original ingredients. The formula expressing
the composition is shown by the following : C^H^.CHjNH,.
Hl.Sblj, mon-^-toluidine iodantimonite.

An examination of the double salts formed from mixtures
4, 5, 6, and 7 indicated that a new variety had been formed.
The appearance of the crystals in the above cases was quite
different from, that of the first compound described. They
consisted of irregular-shaped, bronze-covered leaves. Analy-
ses of a sample of each set indicated that only one individual
had been formed, viz., tri-o-toluidine diiodantimonite,

(C.H,.CH3.NH,.HI),.(SbI,),.

Table X. — Salts of 0- Toluidhie Hydriodide and Antimony
Triiodide.
I. II. III. IV. V. Va. VI. VII.

0

^

M

J2

3

3

3

3

«

3

V2

CO

M
S

C/}

^

t«

tfi

^ — ^

,. — s

^ s,

^^N

VO

s

w

S

S

K

M

w

W

W

w
z

w

w

w

w

0

0

0

0

0

a

-*

a

w

w

K

W

ffi

W

W

w

0

0

0

0

0

u

0

0

u

Theor.

Sb

16.30

19.40

—

12.35

9-95

14.06

8.32

6.28

I

69.02

71.06

70.83

....

65.40

63.18 66.96

61.69

59.81

Exp.
Sb

16.19

....

....

13.89

....

....

....

....

I

68.44

68.63

68.89

66.71

66.67

—

66.33

66.43

Sb

15-88

—

—

I

68.36

68.70

69. CO

66.78

66.37

—

66.25

170

Higbee.

Summary of o-Toluidine Hydriodide and Antim,ony Triiodide

Salts.

C6H4CH3NH2. HI. Sbl3.
Sb. I.

Theor. 16.30 69.02

Exp. 16.19 68.44 68.70

15.88 68.36 68.89
.... 68.63 69.00

Va.
(C6H4CH3NH2.HI)3(Sbl3)2.

Sb. I.

14.06 66.99
13.89 66.71 66.25
66.78 66.37
66.33 66.67
66.43 ••••

Experim-ents with m,-Toluidine Hydriodide and Antimony
Triiodide.

Mixtures of the above ingredients were made up in the
usual way and well-defined crystals began to appear in each
beaker as soon as the solutions were cool. On examination
of the various sets of crystals, by means of the lens, they ap-
peared to be all of the same general character. After re-
moval from the solutions, and drying, the crystals were in the
form of glistening, brick-red prisms.

Analysis pointed, in the case of each of the deposits, to the
formation of only one chemical compound. This proved to be
tri-w-toluidine diiodantimonite, having the formula

(C6H,.CH3.NH,.HI)3.(Sbl3),.

This substance, like the corresponding ortho compound,
seems to possess a strong crystallizing force. A statement of
the analytical results leading to the above formula will be
found in the following tables :

Double Halides of Antimony .

171

Table XI. — Salts of m- Toluidine Hydriodide and Antimony
Triiodide.

II.

III.

IV.

V. Va.

VI.

VII.

j.j

^

4.

rr

r^ HH

(*)

m

>-h' J2

t-H

r^.

^-

'^-

.a

•^ ^

^

.Q

3

U5

^ ^

. CO

"J-

%

HH

s

S

ffi

ffi a

w

w

W
%

K
2

0

0

K
0

0 a

0

K

ffi

ffi

W

ffi

-o

0

a a

0

0

0

0

0

Theor.

Sb

....

14.06

....

I

—

—

66.96

Exp.

Sb

—

13-74

—

I

66.67

66.93

66.86

66.53

66.95

66.89

66.68

Sb

—

I

67.00

66.78

67.08

67.03

66.74

66.26

66.76

Summary of m- Toluidine Hydriodide and Antimony Triiodide

Salts.

Va.

(C6H4.CH3.NH2.HI)3(Sbl3)2

Sb.

I

Theor.

14.06

66.

96

Exp.

13.74 66.77
.... 67.00

66.93

66.78
66.86

67.08

66.53

67.03
66.95
66.74
66.89
66.26
66.68
66.76

Experiments with p- Toluidine Hydriodide and Antimony Tri-
iodide.

In working with this series some diflBculty was met with in
obtaining well-characterized and uniform crystals in the same
beaker. From nearly every mixture worked with there crys-
tallized out side by side light, orange-colored, blunt, pris-

172

Higbee.

matic crystals and darker, orange-colored needles. The pris-
matic forms seemed to be the more soluble of the two, and by
regulating the concentration of the solution it was possible to
obtain a uniform crop of the needle variety. Specimens of
the light prismatic type were gotten out, but on being trans-
formed to a porous earthenware plate, began to turn orange-
red in a very short time.

Analyses of both kinds of crystals, after being dried in the
air, showed that there was no difference in their composition.
The composition of this compound, mono-/i-toluidine iodanti-
monite, is expressed by the formula

aH..CH,.NH,.HI.SbL.

Table XII. — Salts of p-Toluidine Hydriodide and Antimony

Triiodide.

II.

III.

IV.

V.

VI.

VII.

0

d

0"

q

d

d

0

^

w

w

W

w

w

W

M

3

^

^

i_y

HH

kH

hH

1— (

M

1.H H^

ri

r?i

.9

fit

fO

CO

^

J2

^

.Q

,0

.Q

.Q .a

§

3
m

tn

m

i

■^

^

S

(B

!K

Cfi

tn tn

£

^

s

s

S

h- 1

w

s

w

S

s

w

s s

w

w

2

w

w

w

w

ffi

W

w w

;?

^

z

:?;

^.

12;

^

^

^. ^.

q

w

w

q

q

K

X

K

w

w

w

ffi w

0

^

a

q

q

q

q

q

q

q q

W

w

X

W

W

W

W

K

W

W

W

K W

•a
O

0

0

0

0

d

0

0

q

0

0

q

0 0

Theor.

Sb 16.30

19.40

19.12

..

12.35

..

9-95

..

8.32

-.

6.28 ..

I 69.02

67-37

71.06

70.83

..

65.40

63.18

61.69

59-81 ••

Exp.

Sb ....

16.58

—

16.88 ..

16.08

..

..

—

I 69.12

68.86

..

..

68.51

..

68.56

68.42 ..

Sb ....

16.27

16.75

" *

* * ' *

I 69.30

68.67

—

...

• •

68.43

..

—

••

68.37 ••

Sb ....

....

....

....

16.34

. . . .

Rancidity of Fats. 173

Summary of p-Tohiidine Hydriodide and Antimony Triiodide

Salts.

C6H4.CH3

I.

.Hl.Sbla.

Sb.

I

Theor.

1

6.30

69.

02

Exp.

16.58

16.08

69.12

68.43

16.27

16.75

69.30

68.56

16.88

16.34

68.86

68.42

....

68.67

68.37

....

■ • • •

68.51

....

ON THE RANCIDITY OF FATS.

By Iskar Nagel.

Under the direction of the late Prof. Benedikt, in Vienna,
I carried on an investigation on the rancidity of fats and the
refining of rancid oils and fats, and stated that these contain
the following substances in variable quantities :

1. Free fatty acids, saturated as well as unsaturated.

2. Hydroxy acids of the fatty acid series.

3. Lactones and anhydrides of fatty acids.

4. Alcohols, as butyl, amyl, caproyl, and capryl alcohol.

5. Esters of saturated, of unsaturated, and of hydroxy acids
of the fatty acid series with higher and sometimes also poly-
basic alcohols as butyl, caproyl, capryl alcohol, etc. ; gly-
col, etc.

6. Aldehydes, saturated, as butyric, caproic, caprylic alde-
hyde, etc., and unsaturated, as acrolein an oenanthic alde-
hyde.

7. Acetals, which are ether-like compounds of the above-
mentioned aldehydes and alcohols.

8. Terpenes.

There may also be other substances present, but they could
not be identified.

To remove these substances from a crude or rancid fat or
oil, I proceeded as follows :

I. The free saturated and unsaturated acids, as well as the
hydroxy acids, are easily removed by means of an aqueous
solution of soluble glass. If the neutralization is effected with

174 Nag el.

sodium carbonate or with caustic soda, emulsions are obtained,
and it is possible only by a long and tedious method to sepa-
rate the oil from these emulsions, free from water and alkali.
Emulsions are entirely avoided if, instead of the alkalies, an
aqueous solution of glass is used. If such a solution is added
to an oil or melted fat containing free acid, the acid unites
with the bases of the silicates, and silicic acid is set free. The
free silicic acid draws the alkali salts mechanically to the bot-
tom, when it is impossible for them to be dissolved in the oil
and to form an emulsion.

II. The lactones contained in the fats are more or less vola-
tile with water vapor. Some of them, however, are insoluble
in water and not volatile with water vapor. The volatile lac-
tones are removed by the method described under VI. The
non-volatile compounds must be converted into salts of hy-
droxy acids of the fatty acid series. This is accomplished by
boiling for several hours the oil, which contains no free acid,
with concentrated solutions of alkalies, as for instance, with a
small quantity of a solution of sodium carbonate or of caustic
soda. These then become visible in the oil, forming difficultly
soluble flakes which fall to the bottom and are easily filtered
off. These are the salts of the hydroxy acids.

III. The alcohols and esters of fatty acids and of hydroxy
acids contained in fats and oils can be removed by the method
described under VI, provided they are volatile with water
vapor.

IV. Some of the aldehydes are volatile with water vapor
and can be removed according to VI, while others are not,
and these must be removed as follows : Four volumes of oil
are heated for several hours with one volume of a concentra-
ted solution of sodium bisulphite, and, after cooling, the
aqueous solution is separated from the oil. It is known that
the compounds of aldehydes with sodium bisulphite are usually
solid, crystalline bodies, which are always slightly soluble in
the solution of bisulphite. If the aldehydes are present only
in small quantity no crystals are formed, and only a cloudy
layer appears between the aqueous solution and the oil, or
the solution, at first clear, becomes cloudy and contains the

Rancidity of Fats. 175

compounds of the aldehydes with the sodium bisulphite in
solution. These are removed together with the solution.

V. To remove the acetals, if they are not volatile with
water vapor, I have found it best to heat the oil or fat for
some time with dilute sulphuric acid. The higher acetals are
decomposed by the sulphuric acid into alcohols and alde-
h\'des, which are either volatile with water vapor and are re-
moved according to VI or removed according to IV, if vola-
tile. The acetals which are volatile with water vapor are re-
moved according to VI.

VI. The terpenes are all volatile with water vapor and are
removed by distillation with steam. It must be remembered
that it is not always sufficient to conduct ordinary steam
through the oil for the purpose of removing the volatile sub-
stances mentioned under 3-7, since it sometimes has a bad
effect on the oil.

There are some substances which are not volatile or only
very difficultly volatile with steam at 100° C, but which are
more easil)' volatile with steam at a higher temperature.
Hence, the distillation with steam at 100° C. would take a
very long time, and even then would not entirely purify the
oil. On the other hand, it is stated that the continuous con-
tact of heated oils with steam or atmospheric air, while de-
composing the fat, favors the formation of the substances
named under 1-8.

These difficulties may be avoided in three ways :

a. By conducting steam together with some indifferent gas
as hydrogen or carbon dioxide through the oil.

b. By conducting steam under diminished pressure through
the oil.

c. By conducting steam heated gradually from ioo°-i70° C,
together with an indifferent gas through the oil.

If this fractioning with superheated steam is made use of,
those substances which are easily volatile are carried over first,
before the more highly heated steam, which would decompose
them, becomes necessary. It is well to let the oil cool in
vacuo or in an atmosphere of some indifferent gas.

The method above described for purifying fats and oils is
carried out in practice as follows : The fat or oil, freshly

176 Note.

pressed, extracted or already purified with sulphuric acid, is
heated and thoroughly mixed with a concentrated solution of
soluble glass, the quantity depending on the amount of free
acid present, and is then filtered from the heavy precipitate
which has settled to the bottom. The oil is now boiled with
dilute sulphuric acid for about six hours. After cooling, the
sulphuric acid is separated from the oil, which is washed
again with a solution of soluble glass. The oil '3 then thor-
oughly mixed and heated with a fourth of its weight of a mix-
ture of a concentrated solution of sodium carbonate and milk
of lime (1:1) for several hours. In this process a very
small quantity of the oil is saponified, and the soap thus
formed sinks to the bottom. After cooling, the filtered oil is
heated with a fourth of its weight of a concentrated solution
of sodium bisulphite. The mixture is now allowed to cool,
and the aqueous solution is separated from the oil, which is
transferred to a distilling apparatus and subjected to dis-
tillation with steam, the temperature of which is gradually
raised. Finally, the oil is allowed to cool in a current of car-
bon dioxide.

If the oil, before being subjected to the above method of
purification, is carefully examined for those substances which
are not glycerides of the fatty acids, or, if it is known that
some of the substances above named (1-8) are not present,
then such parts of the method as have for their object the re-
moval of these substances, may be omitted. Further, the
success of the method does not depend on the order of pro-
cedure described above. This may be changed at pleasure.

NOTE.
The Wax of the Badllariaceae a?id Its Relation to Petroleum.

In a recent number of the Berichte (32, 2940) there is an
article on this subject by Kramer and Spilker, an abstract of
which is herewith given :

' ' The oil which has long been known to exist in the Badl-
lariaceae (Diatoms) had not been investigated until the
authors undertook the task of tracing the probable relation-
ship between it and mineral waxes and oils. These unicellu-
lar plants, whose siliceous coverings form immense deposits in

Note. Ill

some places, are very abundant in peat-bogs. A quantity of
the dried material was extracted with benzene, and yielded a
brownish-black wax-like mass, which contained a high per-
centage of sulphur on account of the presence of the so-called
' sulphur bacteria', which set free this element from certain of
its compounds. Fortunately, an immense deposit of material
nearly free from sulphur was found at I^udwigshof. In the
bed of a lake recently drained was a layer of diatom remains
of an average thickness of 7 meters and covering an area of
900 hektares (2200 acres). This elastic, slimy mass con-
tained about ID per cent of dry substance. This yielded 3.6
per cent of wax when extracted, so that the amount obtaina-
ble from the entire deposit would be about 250,000 tons.

"The dark-brown wax was scarcely acted on by fuming
nitric acid in the cold, but nearly 40 per cent dissolved on
warming. The residue, when cr5'stallized from alcohol,
yielded a viscous oil, and a white solid in all respects similar
to 'lekene', obtained from mineral wax by Beilstein and
Wiegand.' When distilled the wax gave off methane, the
oxides of carbon, sulphuretted hydrogen, and water, besides
an oily distillate. Mineral wax (ozocerite) similarly heated
gives off only traces of the oxides of carbon and sulphuretted
hydrogen, and no water. It is very slightly saponified by
alcoholic potash, but about 10 per cent of diatom wax is
dissolved. From the alkaline solution ether extracts a brittle
gum.

"When distilled under pressure, the two kinds of wax yield
very similar products, except that the mineral wax yields no
oxides of carbon, no water, and only traces of sulphuretted
hydrogen, all of which are given off from diatom wax. In
both cases unsaturated gaseous and liquid hydrocarbons are
formed. When the liquid products are subjected to fractional
distillation, the portions boiling between 130° and 290° are
found to be identical.

" For comparison, Carnauba wax and Japan wax were dis-
tilled under the same conditions. The gaseous products re-
sembled those from diatom wax, except for the absence of
sulphuretted hydrogen, and the liquid distillates were prac-
tically identical with those above mentioned. In all four cases
the middle fraction (i3o''-290°) had a molecular weight and
composition agreeing fairly well with the formula C,;H,^.
This was after the removal of the unsaturated constituents.

"The authors believe that mineral waxes and oils are
formed from diatom wax by the combined action of heat,
pressure, and ammonium carbonate (formed by the decay of

1 Ber. d. chem. Ges., 16, 1547.

lyS Obituary.

protoplasm). Deposits such as that at I,udwigshof were
probably formed in remote ages, and were covered by debris
from the surrounding hills, so that great pressure would be
exerted on the mass. The heat of the earth's interior would
cause a distillation of the wax, and its transformation into the
various kinds of petroleum, according to the conditions. The
unsaturated hydrocarbons poh^merized to form the viscous,
heavy oils.

" It is hard to imagine conditions favorable to the accumu-
lation of animal remains in sufficient abundance to form the
petroleum deposits, but it is not difficult to believe that, in
earlier ages, when the conditions for vegetation were so favor-
able, there might have been formed layers of diatomaceous
material much larger than the one at Ludwigshof. It is not
improbable, however, that certain petroleum deposits, e. g. in
the oil shales, are of animal origin. Unfortunately, no re-
mains of diatoms have been found in the oil sands or in the
overlying rocks, but this may be due to the corroding action
of ammonium carbonate on the very delicate siliceous cover-
ings. Further, the overlying rock contains a very high per-
centage of silica, as it should if formed mainly of the remains
of diatoms. O. N. Witt,' in discussing Engler's petroleum
theory, suggested that diatoms ought possibly to be taken into
account. Finally, however, he gave up the idea because no
remains of diatoms have been found earlier than the tertiary
deposits. The authors suggest that such remains would have
been so corroded by percolating water in the course of ages
that they would be unrecognizable.

"A. F. Stahl, also,^ states that the theory of the formation
of petroleum from animal fat is not supported by his observa-
tions in the Kalmuch and Kirgis steppes. He believes the
oil was formed from diatoms, but made no experiments along
this line.

' ' There may be points in regard to the above theory which
geologists may object to, and it is evident that the correct
solution of the problem cannot be attained without the aid of
both geologists and chemists." C. E. w.

OBITUARY.

JOHANN CARI, WILHELM FERDINAND TIEMANN.

News has recently reached us of the death of Prof. Tiemann,
which occurred November 14. He was born in 1848 and took
his Ph.D. degree at Gottingen in 1870. Since 1882 he has

1 Prometheus, 1894, 349, 365.

2 Chem. Ztg., Feb. 22, 1899.

Reviews. 179

been Professor of Chemistry in the University of Berlin and
editor of the ' ' Berichfe der dezdschen chentischen Gesellschaft. ' '
He has always been active in the field of pure chemis-
try, his work on camphor being perhaps his best known con-
tribution to the science. His energies have been, however,
on account of his connection with the firm of Haarman &
Reimer, especially directed toward the development of com-
mercial products. He introduced artificial vanillin, prepared
at first from coniferin and later from eugenol, and succeeded
in perfecting a method for the preparation of ionone, a sub-
stance he had discovered and shown to be the essential prin-
ciple of the odor of the violet. His w^ork on the geraniol
alcohols and citral is also a valuable contribution to that
branch of the science. He was closely related by marriage to
both Hofmann and Kuno Fischer. j, E. G.

REVIEWS.

Theoretische Chemie. Vom Standpunkte der Avogadro'schen Regel
und der Thermodynamik. Von Dr. Walter NernsT, o. Professor
und Direktor des Instituts fiir physikalische Chemie an der Universitat
Gottingen. Zweite Auflage, mit 36 in den Text gedruckten Abbild-
ungen. Stuttgart : Verlag von Ferdinand Enke. pp. 703. 1898.

The three great books which mark the progress of physical
chemistry towards the close of the nineteenth century are the
Lehrbuch and Griindriss of Ostwald, and the Theoretische Chemie
of Nernst. The subject-matter is treated quite differently by
Ostwald and by Nernst, and each of these works has its
peculiar and distinctive advantage. The third edition of the
Griindriss has just appeared, and the second edition of the
Lehrbuch, though not completed, seems to be already ex-
hausted. The second edition of the Theoretische Chemie has
now appeared, just five years after the first. The method of
treatment adopted by Nernst in the new edition is essentially
the same as in the first. The volume is divided into four
books : The General Properties of Substances ; The Atom
and Molecule ; The Transformations of Matter ; and The
Transformations of Energy. But each book is enlarged, in-
corporating the work of the last few years. This applies es-
pecially to the sections on electrochemistry. This field, in
which Nernst has played such a prominent role, was discussed
very briefly in the first edition, presumably because of its ex-
haustive development by Ostwald in the Lehrbuch. In the
new edition electrochemistry is treated more fully and in a
broader way. h. section is devoted to the general facts per-
taining to electrolytic conduction, electrolysis, etc. This is

i8o Reviews.

followed by an application of thermodynamics to tlie action of
the cell, which we owe primarily to Helmholtz and Thomson.
In this section paragraphs are devoted to the transformation
of chemical energy into electrical, the calculation of electro-
motive force from thermodynamics, the application of thermo-
dynamics to the lead accumulator. In the final section the
application of the laws of osmotic pressure and the theory of
electrolytic dissociation, to the problem of the electromotive
force of elements, is made at some length. And this is the
most interesting and important chapter in electrochemistry,
since it has given us, for the first time, a rational theory of
the cell. Paragraphs are devoted to the way in which cur-
rents are produced in solutions, solution of metals, theory of
the origin of the galvanic current, concentration elements, the
gas battery, etc.

The only criticism that can fairly be made is that the work
is a masterpiece, containing new and original suggestions at
every turn. But this is just what we should expect from a
leader.

The lack of an adequate appreciation of the great merit of
this work, manifested in a recent review in this country, is
a source of deep regret to the writer of this notice.

Harry C. Jones.

Vol. XXIII. March, 1900. No. 3.

AMERICAN

Chemical Journal

Contributions from the Chemical Laboratory of Cornell University.

ANETHOL AND ITS ISOMERS.
[second paper.']

By W. R. Orndorff and D. A. Morton.
ANETHOL.

/. Physical Properties .

The anethol used in this work was a product of exceptional
purity*. It melted at i9°-2i°.5 C, and distilled completely
between the temperatures 231°. 5 and 232°. 5 C. (uncorr.). A
sample portion distilled completely with steam, leaving no
residue. A still purer product was obtained by recr5'stalliza-
tion of the commercial anethol from ordinary alcohol (93.7
per cent). After recrystallization the product melted at 22°. 5
C, and this melting-point remained unchanged after further
recrystallization from this or other solvents. The boiling-
point of this purest product was taken, using a standard ther-
mometer, the mercury column of which was entirely sur-
rounded with the vapor of the boiling liquid, and found to be
233°. 6 C. at 731 mm. barometric pressure.^

1 See This Journal, 19, S45, for the first paper on this subject.

2 This anethol was purchased from Fritzsche Bros., of N. Y. City, a branch of
Schimmel & Co., of Leipsic.

3 This thermometer registered o°.i too high at this temperature according to the
Priifungs-Bescheiuiguug of the Physikalisch Technische Reichsanstalt, Abtheilung
II, Charlottenburg, Germany. The correct boiling-point is therefore 233°.5 C.

i82 Orndorff and Morton.

The pure product still possessed a slight anise odor, but this
was not nearly so pronounced as in the commercial product.
It is soluble in all proportions in chloroform, ether, acetic
ether, acetone, benzene, absolute alcohol, carbon disulphide,
aniline, and petroleum ether. It is less soluble in ordinary
alcohol (93.7 per cent), and may be crystallized from this sol-
vent by cooling the solution down to 0° C. In water it is very
slightly soluble, but sufficiently to impart its c'laracteristic
taste and odor to this liquid. From petroleum ether it may-
be crystallized by cooling the solution sufficiently.

The freezing-point of the commercial anethol, using the
Beckmann freezing-point apparatus, was found to be 20'. 55
C. as the mean of three very careful observations. When re-
crystallized from alcohol twice the purified product solidified
at 21°. 4 C, and further recrystallization from alcohol or from
petroleum ether did not change this freezing-point. Hence
the product must be regarded as pure.

The statement is made by Grimaux' that when heated to
100° C. for some time, the melting-point of anethol is lowered
in consequence of the formation of polymers. In repeating
this work it was found that, after heating anethol for nine
hours on the water- bath, its melting-point was lowered about
5°. Further heating at its boiling-point (230° C.) for three
hours lowered the melting-point about 1° more, and the prod-
uct now left an appreciable residue when distilled in steam.
This residue was a dark-colored, thick, viscous oil, heavier
than water, and appeared to be identical with the product
called isoanethol, obtained by Kraut and Schlun^ by heating
fluid metanethol in sealed tubes at 330° C. for several hours.
In purif3dng anethol by distillation it is therefore better to
distil in steam or under reduced pressure in order to avoid this
polymerization as much as possible. The method of purifica-
tion by crystallization is of course not open to this objection
and is to be preferred to all others.

From alcohol anethol crystallizes in extremely thin, rec-
tangular plates, which show parallel extinction and a biaxial
optical interference figure in converged polarized light. The

1 BuU. Soc. Chim. (Paris), (III), 15, 778.

2 Arch. d. Pharm. (2), 116, 241.

AnetJiol and Its Isomers. 183

acute bisectrix is apparently at right angles to the flat plates ;
hence the symmetry is most probably orthorhombic, though
possibly monoclinic.

//. Chemical Conduct.

A. The Actio7i of Iodine on Anethol. — A concentrated solu-
tion of iodine in acetone or potassium iodide acts at once
on anethol, with evolution of heat, converting it into
its polymer anisoin. Iodine alone effects this change on
standing with anethol for a long time, or immediately, if the
two are heated together. On the other hand, a concentrated
alcoholic solution of iodine has no polymerizing action on
anethol.

B. The Action of Hydrochloric Acid 07i Anethol. Anethol
Hydrochloride. — The method employed in the preparation of
this compound was slightly different from the one used by
Saussure' and Cahours' in the respect that, instead of sub-
jecting the solid anethol to the action of the gas, the latter
was conducted into the melted substance, care being taken to
maintain as low a temperature as possible and still keep the
anethol in fluid condition. The anethol was first weighed,
then hydrochloric acid gas passed in until the weight no
longer increased. The reaction-product was a thick oil and
had a reddish or greenish tinge when first prepared.

The amount of hydrochloric acid that anethol can absorb
was determined in a few cases, as follows :

ID grams anethol absorbed 3 grams of dry hydrochloric acid
gas. (Theory requires 2.5 grams for the compound,

.0CH3(/>)

\CH,CHC1CH/

30 grams anethol absorbed 8.5 grams HCl. (Theory 7.5
grams.)

14.26 grams anethol absorbed 3.43 grams HCl. (Theory
3.52 grams.)

In the last determination the weighings were carefully made

1 Ann. chim. phys. (i), 13, 282 (1820).

2 Ibid. (Ill), 3, 279 (1841).

184 Orndorff and Morton.

and the results are correspondingly accurate. The other de-
terminations were merely approximate.

Grimaux' states that the quantit}' of hydrochloric acid ab-
sorbed by anethol does not appear to be definite since he found
it to vary by as much as 2 per cent in different experiments.
He considers that the action is not an additive but a polymer-
izing one, the anethol being changed to isoanethol which
holds in solution a variable amount of hydrochloric acid.
The results of our work, however, do not bear out this sup-
position. On the contrary, they agree with the results ob-
tained by Saussure and Cahours, both of whom found that
anethol absorbed exactly the amount of hydrochloric acid re-
quired by theory for the formation of a compound of the for-
mula, C,„H„0.HC1.

The anethol hydrochloride is very unstable, and gives off
hydrochloric acid fumes constantly on standing at ordinary
temperatures, the decomposition being apparently the same as
that which takes place on distillation ; namely, the splitting
off of hydrochloric acid and formation of isoanethol. Appar-
ently this decomposition takes place to a slight extent even
during the preparation of the anethol hydrochloride. If it is
allowed to go too far anomalous analytical results are to be
expected.

When anethol hydrochloride is treated with alcoholic caus-
tic potash several products result. Besides isoanethol and
solid metanethol a light oil is formed which distils with steam
and has a pleasant mint-like odor. This is an alcohol addi-
tion-product of anethol and will be described in another part
of this paper.

C. The Action of Picric Acid on Anethol. — The picrate of
anethol has been described b}^ Ampola' as a solid crystalli-
zing from alcohol in carmine-red needles melting at 60° C.

In order to compare closely the conduct of anethol with that
of fluid metanethol the action of picric acid on both these
compounds was investigated.

The picrate of anethol was easily formed b}^ adding the cal-
culated amount of picric acid to a solution of anethol in alco-

1 Bull. Soc. Chim. (Paris), (III), is, (1S96) 778.

2 Gazz. chim. ital., 24 (1894), 432.

Anetlwl and Its Isomers. 185

hoi. The picrate could then be precipitated out with water
or crystallized out by evaporation of the alcohol. The pure
substance melted with decomposition at about 70° C. On stand-
ing in the air it gradually breaks down into anethol, which
volatilizes, and picric acid. Alcoholic caustic potash decom-
poses it immediatelj^ into anethol and potassium picrate.

D. The Action of Bromine on Anethol. Anethol Dibromide.
— This compound was prepared by lyadenburg's method.' It
decomposes so readily that its crystallographic constants
could not be determined. The melting-point of the pure
crystals was determined as 63°-64° C. (according to Ivadeu-
burg 65° C), but as the substance decomposes at its melting-
point or even at a still lower temperature, an accurate deter-
mination could not be made.

Monobromanethol Dibromide. — Following the directions of
Hell and Garttner,^ this compound was prepared b}^ adding
graduall}' to a cold ethereal solution of anethol slightly more
than 2 molecules of bromine. The first half of the bromine
should be added gradually, as the reaction is violent, until all
the anethol is converted into the dibromide. The remainder
of the bromine can then be added all at once, as the substitu-
ting action is slow. The ethereal solution, if left to evaporate
spontaneously, will then deposit the crystalline monobrom-
anethol dibromide.

Hell and Garttner purified this product by repeated crys-
tallization from petroleum ether, but this method is slow and
unsatisfactory, since, in the first place, the compound does
not dissolve easily in petroleum ether, and, in the second
place, it requires a number of recrystallizations to remove the
impurities. It was found, however, that the compound could
be easil}' and quickl}^ purified b}^ dissolving it in a small
amount of chloroform and then adding alcohol to this solution
until precipitation began. The monobrom dibromide is then
deposited in the form of slender prisms, which melt sharply at
102° C, the melting-point being unchanged by recrystalliza-
tion from chloroform-alcohol or from ether. When heated

1 Ann: Chem. (Liebig), Suppl. Bd. 8, 87 (1872).

2 J. prakt. chem., 51 (1895) 424 ; see also Ibid., 5a, 193 (1S95).

1 86 Orndorff and Morton.

rapidly the melting-point is somewhat higher than the one
just given.

The same monobrom dibromide results, either by shaking
anethol with bromine water until no more bromine is absorbed
and then treating the resulting dibromide in ethereal solution
with another molecule of bromine ; or, by adding the calcula-
ted amount of bromine directly to anethol.

Monobromanethol dibromide is slowly decomposed if its
solution in acetone, ether, chloroform, or chloroform-alcohol
is kept warm for any length of time. It was therefore diffi-
cult to obtain very good crystals, although it is a substance
that would otherwise crystallize unusually well. The best
crystals were obtained by allowing the chloroform-alcohol
solution to cool somewhat slowly.

The crystals are doubly refracting. They show the biaxial
optical interference figure in converged polarized light, but in
no case parallel extinction. The optical properties as well as
the form of the crystals show them to belong to the triclinic
system.

The four angles in one crystal zone were measured in order
to compare them with the same angles on the crystals of the
corresponding fluid metanethol compound. For the obtuse
angles the best measurements were : 97°43'. 97°42', 97°48'.
and 97°44' ; for the acute angles : 82°22' and 82°i4'. Average
97=44' and 82°i8'.

E. The Action of Nitrogen Trio xide on. Anethol. — The nitro-
site and its anhydride were prepared by the method of Ton-
nies' for the purpose of comparing their properties with those
of the analogous fluid metanethol derivatives. The following
method of preparation was finally adopted.

The theoretical amount of sodium nitrite, dissolved in
water, was added to a solution of anethol in three times its
volume of glacial acetic acid. The mass immediately became
viscous and turbid, but it was only after standing several
hours that it became nearly solid from the formation of crys-
talline material. It was then filtered and the contents of the
filter recrystallized from ether. Crystals separated from this
solvent in the form of long, slender prisms showing very clear

1 Ber. d. chem. Ges., ii, 1511 (1878).

Anethol and Its Isomers. 187

faces and melting at 98° C. This compound is the anethol
nitrosite anhydride or, as Boeris' calls it, diisonitrosoanethoil
peroxide.

The nitrosite itself was obtained in small quantity by al-
lowing the sodium nitrite and alcohol solution to react to-
gether for a much shorter time — about one-half hour — and
treating the resulting viscous mass with ether. A por-
tion of the mass dissolves in the ether and another part is de-
posited in fine needles which melt at about 130° C, and agree
in properties with the anethol nitrosite described by Tonnies.

OCH3 CH3

An attemptto prepare the glycol, CeH,— CH(OH)CH(OH) ,
from this compound, following as closely as possible the di-
rections of Tonnies, proved unsuccessful. Attempts to make
it by Wagner's^ method, by the oxidation of anethol with a i
per cent solution of potassium permanganate, were equally
unsuccessful.

The anhydride of the nitrosite crystallized exceedingly well
and appeared to be perfectly stable at ordinary temperatures.

A microscopical examination showed the crystals to be
doubly refracting and biaxial, and to contain a single plane of
symmetry perpendicular to a binary axis of symmetry. They
are consequently monoclinic holohedral. A large number of
measurements of the six angles in the orthopinacoid zone
gave closely agreeing numbers. The average measurements
for the angles were : 98°46', 33°io',5, and 48^2', respectively.

F. The Action of Nitrosyl Chloride on Anethol.^ — The nitro-
sochloride was prepared in several different ways, all of them
based on the use of nascent nitrosyl chloride. The best re-
sults were obtained by passing hydrochloric acid gas into an
ethereal solution of anethol and amyl nitrite, as follows :

A slow current of dry hydrochloric acid gas was conducted
into a mixture of 10 grams anethol and 8 grams amyl nitrite
dissolved in 30 grams of ether. Each bubble of hydrochloric
acid gas produced a transient brown color. In a few minutes

1 Gazz. chim. ital., 21, 1S3 (1891).

2 Ber. d. chem. Ges., 24, 3488 (1891).

3 Tonnies : Ber. d. chem. Ges., 12, 169 (1879) ; Tilden and Forster : J. Chem.Soc,
65. 330 (1894)-

1 88 Orndorff and Morton.

tlie mixture became nearl}^ solid with the nitrosochloride crys-
tals. These were then filtered off and hydrochloric acid gas
again passed into the mother-liquor until it once more became
nearly solid with cr3^stals. After this operation had been re-
peated three or four times the addition of hydrochloric acid
gas to the mother-liquor no longer produced a precipitate, but
still more of the nitrosochloride separated from the mother-
liquor on the addition of alcohol. Finally, the addition of
water to the remaining liquid precipitated a small amount of
oil}^ matter. The total yield of anethol nitrosochloride ob-
tained by this method was somewhat more than 50 per cent of
the theoretical amount. The product was very nearly pure
when first prepared, and it is probable that a much larger
yield could have been obtained by this method by careful
manipulation and the use of pure amyl nitrite instead of the
commercial product.

The pure nitrosochloride, when heated slowly, melts with
violent decomposition at 123° C. Tilden and Forster give its
melting-point as 127° C. It dissolves easily in chloroform, is
moderately soluble in toluene, benzene, and acetic ether,
slightl}^ soluble in hot absolute alcohol and acetone ; and al-
most insoluble in ordinary alcohol, ether, carbon disulphide,
and petroleum ether. It decomposes when heated in solution
in chloroform, toluene, acetone, or glacial acetic acid.

The crystals separate from chloroform in the form of tabu-
lar plates. An examination of their optical properties showed
them to be biaxial, and to give oblique extinction whether
examined perpendicularly to their broad surfaces or in cross
section. They are therefore triclinic.

FLUID METANETHOL.

The preparation of this compound was carried out in the
usual way ; namely, by distillation of anisoin and careful sepa-
ration of the resulting products. For this purpose only pure
anisoin, precipitated carefully from acetone solution by alco-
hol, was used.

The distillation-products of the anisoin were separated by
fractional distillation into three distinct compounds. One, of
boiling-point 175° C, has been identified as the methyl ether

Anethol and Its Isomers. 189

/OCH3

of paracresol, C6H^<' ; the second, which boils at 228°-

232° C, is fluid nietanethol ; and the third, whose boiling-
point is above 360° C, is the substance known as isoanethol.

The purification of the fluid metanethol was a tedious pro-
cess. It underwent slight change when distilled under atmos-
pheric pressure so that only an approximate degree of purity
could be attained by this means. B5' distillation under
diminished pressure (40 mm.), the purification was carried
much farther, although even then slight change appeared to
take place, and it was only after seven complete fractionations
that a product of sharp boiling-point (i42'^-i43° C. under 40
mm. pressure), and freezing-point (10°. 4-10°. 7 C), was iso-
lated.

This compound was finally obtained completely pure by
repeated crystallization from alcohol. After one crystallization
its melting-point rose to iS°-i9° C. Recrystallized once more
it became 22^.5 C, and after another recrystallization it still
melted at 22". 5 C. This then is the melting-point of pure
fluid metanethol, and it is exactly the same as the melting-
point of pure anethol. The odor and taste also of this prod-
uct could not be distinguished from the odor and taste of pure
anethol, and its boiling-point was found to be the same as that
of pure anethol.

The crystals of the fluid metanethol from alcohol could, in
no way, be distinguished from the crystals of anethol from the
same solvent. The}' formed very thin, nearly square, rec-
tangular plates, showing the same biaxial interference figure
and probable orthorhombic symmetry as the anethol crystals.

Towards chemical reagents the fluid metanethol was found
to behave in every instance in exactly the same wa}^ as
anethol, as the following experiments show :

A. The action of iodine in concentrated solution in aqueous
potassium iodide on fluid metanethol gave a brown, tarry
mass, which dissolved easily in acetone and was precipitated
from this solvent, by the addition of alcohol, as a white,
amorphous powder, having the same appearance and proper-
ties as anisoin.

190 Orndorff and Morton,

B. A current of dry hydrochloric acid gas passed into fluid
metanethol changed it into a heavier oil which could not be
distinguished from a specimen of anethol hydrochloride pre-
pared at the same time. Ten grams of the fluid metanethol
absorbed 2.5 grams of dry hydrochloric acid gas — 2.47 grams
being the theoretical amount required for the formation of
fluid metanethol hydrochloride, Cj^Hj^O.HCl. On treating
this hydrochloride with alcoholic caustic potash and distilling
the resulting product with steam, a light oil passed over.
This had a peculiar mint-like odor and yielded anethol on
distillation. The oil which resulted by similar treatment of
anethol hydrochloride had these same properties and was
identified as the alcohol addition-product of anethol,

C,„H,,O.C,H,OH.

C. The addition of picric acid to an alcoholic solution of
fluid metanethol immediately caused the solution to turn red,
owing to the formation of the picrate. On evaporation, or by
addition of water to the solution, the picrate separates out in
the form of bright-red needles, which melt approximately at
70'' C. The compound decomposes at its melting-point and is
identical in appearance and properties with the corresponding
anethol compound.

D. Dibromide of fluid metanethol : This compound was
prepared in the same way as the anethol dibromide : that is,
by adding bromine, drop by drop, from a burette to a cooled
solution of fluid metanethol in ether, until a drop imparted its
color to the whole solution. The excess of bromine was re-
moved by shaking the mixture with water saturated with sul-
phur dioxide. The washed ethereal solution then left behind
on evaporation a mass of needle-shaped crystals, which were
easily obtained pure by recrystallization from petroleum ether.
Their melting-point was determined at 63°. 5 C. This com-
pound could, in no way, be distinguished from anethol dibro-
mide.

Monobromine derivative of the dibromide of fluid metane-
thol : This compound was prepared in exactly the same way
as the corresponding anethol compound. The melting-point
of the pure product was determined as 102° C. As to its

Anethol and Its Isomers. 191

crystal appearance, solubility, and stability, it is only neces-
sary to repeat what has been said in this connection about the
corresponding anethol compound. A microscopical examina-
tion showed the crystals to belong to the triclinic system.
The same angles were measured as in the case of the mono-
bromanethol dibromide and the following results obtained :
Average for the obtuse angles 97° 56'; for the acute angles
82° 6'.

E. The nitrosite and nitrosite anhydride of fluid metan-
ethol, prepared in the same way as the anethol compounds,
did not differ from them in any way so far as could be de-
tected. Only a small amount of the nitrosite was obtained,
but enough to determine its melting-point, which was found
to be i25°-i3o'' C. The anhydride was formed in larger
quantity and was more carefully examined. The following
characteristics were determined : The compound crystallizes
in long, slender, slightly yellow crystals which melt at 98° C.
Crystallographically they differ in no respect from the crys-
tals of anethol nitrosite anhydride. The angles in the ortho-
pinacoid zone of a number of crystals were measured, the
average angles being found to be 98°46'.5, 33°ii', and 48°2',
respectively.

F. The action of nascent nitrosyl chloride on fluid metan-
ethol produces a compound of the same appearance, melting-
point, solubility, and stability as the nitrosochloride of an-
ethol. The symmetry and optical properties of the crystals
were determined and the same results obtained as in the case
of the anethol compound.

.By a comparison of the entire conduct of fluid metanethol
with that of anethol it will be seen that it is the same sub-
stance. There is therefore no longer any need of the name
fluid metanethol to designate the chief product of the distilla-
tion of anisoin, as it is, in reality, anethol.

A few other investigations will now be described, first con-
sidering the action of alcoholic caustic potash on anethol hy-
drochloride.

The Alcohol Addition-product of Anethol, Cj^H^^O.CjH.OH.

The addition of a slight excess of alcoholic caustic potash

192 Orndorff and Morton.

to anethol hydrochloride at first produced no visible effect,
but the mixture soon began to get warm and deposited a
copious precipitate of potassium chloride. The mixture was
then washed with water, to remove the alcohol and inorganic
compounds, and distilled with steam,

Two products were obtained by this treatment in about
equal quantities. One, an oil resembling anethol, passed over
with the steam. The other remained in the distilling-flask as
a semi-solid mass, heavier than water, and was found to con-
sist chiefly of isoanethol and solid metanethol.

The part of the mixture that passed over with the steam
was a thin, colorless oil, lighter than water, and had a strong,
pleasant, mint-like odor, entirely different from that of an-
ethol. The following experiments showed this substance to
be an alcohol addition-product of anethol of the formula

C,„H,,O.C,H,OH,

(i) The purest product, in ether solution, would take up
only one-twelfth the amount of bromine that the same weight
of anethol would absorb. It is consequently saturated, there
being no doubt that, when entirely free from anethol, it would
not absorb bromine at all.

(2) When heated no change is visible until the temperature
reaches 20o°-2io° C. Bubbles then begin to rise from the
bottom of the flask and, as the temperature is further in-
creased, the liquid boils vigorously. On distillation, 13 grams
of the compound yielded the following products :

(a) 2.5 grams of a liquid having the odor and boiling-point
of alcohol, and yielding iodoform when treated with potas-
sium hydroxide and iodine. This liquid is evidently alcohol.

{b) Approximately 9 grams of a liquid boiling at 225°-230°.
This solidified in a freezing-mixture of hydrochloric acid and
ice and, by its odor, melting-point, and boiling-point, was
identified as anethol.

(r) There still remained in the distilling-flask about 2
grams of a reddish liquid from which crj^stals of solid metan-
ethol separated on cooling.

The relative quantities of anethol and alcohol obtained in
this experiment indicate that they were present molecule for

Anethol and Its Isomers. 193

molecule in the original compound, to which we must accord-
ingly assign the formula Ci^Hj^O.CjHjOH. Structurally it
should probably be represented by one of the two following
formulas :

OCH3 OCH3

C,H,— CH— CH— CH3(/') or CcH.—CH—CH—CH, (;!)).

\ \ \ \

OC,H, H H OC,H,

This alcohol addition-product of anethol probably results
from the anethol hydrochloride in accordance with the follow-
ing equation :

/OCH3 /OCH3

CeH/ +koc,h=c,h/ +Ka.

VH— CH,CH3 ^CH— CH,CH3

I I

CI OC,H,

The decomposition of the product on heating would be rep-
resented as follows :

/OCH3 /OCH3

CeH/ = C,H / + C,H,OH.

^CH CHCH3 \CH=CHCH,

Perhaps the product obtained by Hell and von Gunthert*
by the prolonged action of boiling alcohol on anethol dibro-
mide has an analogous constitution. This compound, from
the percentage of bromine it contained, was judged to have
the formula Cj„Hj3BrO.C2Hj,OH, and might be regarded as
the alcohol addition-product of bromanethol,

/OCH3
CeH/

\CHBrCH0C,H,CH3

The alcohol addition-product of anethol is but slightly de-
composed when distilled with steam. When distilled directly
under diminished pressure (40 mm.) the decomposition is
greater, but still the larger part remains unaltered.

1 J. prakt. Chem., 52, 199 (1895).

194 Orndorff and Morton.

Anethol Hydrobromide.

The hydrobromide of anethol is not mentioned in the liter-
ature. It is formed by the action of dry hydrobroraic acid
gas on anethol in the same way that anethol hydrochloride is
formed by the action of dry hydrochloric acid.

A current of dry hydrobromic acid gas was passed into 20
grams of liquid anethol until further addition no longer in-
creased the weight. It was found that 12.5 grams of hydro-
bromic acid had then been absorbed. In order to remove any
excess of hydrobromic acid air was then passed through the
liquid until the fumes of the acid, which were copiously
evolved at first, ceased to be given off, and even its odor could
not be detected. By this treatment with air the product lost
1.5 grams in weight, hence there remained 11 grams of hydro-
bromic acid in combination with the anethol. The calculated
amount with which 20 grams of anethol should unite to
form the hydrobromide, C,„H,,O.HBr, is 10.95 grams ; and,
as succeeding experiments confirmed these results, there can
be but little doubt that this formula correctly represents the
compound formed in this reaction.

The freshly prepared, crude hydrobromide was tinged
slightly green, but became colorless when washed with water.
It had previously been noticed that anethol hydrochloride
sometimes had this same color when first prepared.

Anethol hydrobromide is a heavy oil of the same consis-
tency and general appearance as the hydrochloride. It does
not decolorize a trace of bromine and is consequently satura-
ted. When it is decomposed with alcoholic caustic potash
and the resulting oil is distilled, the products are the same as
result from the distillation of anethol hydrochloride — anethol
and isoanethol.

The hydrobromide reacts readily with aniline, pyridine,
piperidine, or zinc dust, yielding resinous products that were
not fully identified, but which consisted in part of isoanethol
and solid metanethol.

The Action of Sulphuric Acid on Anethol.

Anethol itself apparently does not dissolve in sulphuric
acid. Dilute sulphuric acid has no appreciable effect upon it

Anethol ajid Its Isomers. 195

unless the two are left in contact for a considerable time.
The concentrated acid polymerizes it at once into anisoin, and
the latter dissolves slowly, yielding a red solution. Hot con-
centrated, or fuming, sulphuric acid acts violently on anethol,
causing a rapid evolution of sulphur dioxide and completely
charring the mass which is left.

It is stated by Cahours' that the red solution, formed b}'- the
action of sulphuric acid on anisoin, contains an acid substance
which unites with baryta and lime with the formation of
resinous products. These he did not further examine.

In order to determine the nature of this acid we have pre-
pared and examined it as follows : 5 grams of anethol were
treated, drop by drop, with concentrated sulphuric acid until
about 20 grams of the latter had been introduced. The ani-
soin, which was first formed, dissolved very slowly, but at the
end of two daj-s had wholly disappeared. After standing still
another day the addition of a liter of water to the red solution
did not produce the least turbidity. This diluted solution
was nearly neutralized with precipitated chalk, filtered, and
the filtrate, after the addition of a little lime-water, evapora-
ted to small bulk on the water-bath. The residue was a
resinous mass which dried to a powder on still longer stand-
ing, the latter being extremely soluble in water, although very
insoluble in alcohol, acetone, or ether. Attempts were made
to crystallize it from water or a mixture of water with methyl
or ethyl alcohols, but the same gummy product always sepa-
rated out. It was not sufficiently soluble to crystallize from
solvents containing no water, and, when any water was pres-
ent, enough would be taken up by the substance to form a
resinous mass.

The substance was finally dissolved in alcohol (50 per cent)
and reprecipitated by the addition of alcohol (90 per cent).
The white powder thus obtained was subjected to the same
treatment again and then dried at 120° C. until its weight was
constant. An analysis of this dried product for calcium gave
the following results :^

1 Ann. chim. phys. (Ill), 2, 274 (1841).

2 In the calculation of all the analyses in this work the atomic weights used
were : C = 12, O = 16, H = i, S = 32, Ca = 40.

196 Orndo7-ff and Morton.

I. 0.2550 gram substance gave 0.0723 gram CaSO^.

II. 0.2454 gram substance gave 0.0679 gram CaSO^.

Calculated for Calculated for Found.

(C,oH,30S04),Ca.(C,oH,,OS03)2Ca. I. II.

Ca 7.54 8.1 8.34 8.13

Although from the method of preparation and properties of
the salt it was expected that it would agree in composition
with the first formula, the analyses indicate tha* the second
formula is correct. Gerhardt' made an acid by the action of
concentrated sulphuric acid on the so-called fluid metanethol,
to which he gave the name sulphanethinic acid. From this
acid he prepared the barium salt, which resembled the above
calcium salt closely and on analysis gave results in accord
with the formula (C,„H„0S03),Ba+ 2H,0.

A7iethol Dihydride {Parapropyl Anisol') .^

The reduction of anethol was accomplished by adding to
its solution in absolute alcohol three times the theoretical
amount of sodium necessary for the formation of the dihydro
addition-product. The sodium was introduced in bits the
size of a pea, the whole operation taking perhaps two hours.
The yield of the reduction-product was found to be much
larger when the reaction took place at as low a temperature as
possible than when it took place at the boiling temperature of
the alcohol. Under the former conditions a 50 per cent ^deld
was obtained.

The addition of water to the reaction-products precipitated
an oil which, after being washed, dried, and fractionally dis-
tilled, was found to contain, besides anethol, a liquid which
boiled at 2io°-2i4° C. This would unite directly with only
about o. I the amount of bromine that would be absorbed by
the same weight of anethol. It was evident from this conduct
that the reduction-product was a saturated compound but
still containing as an impurity a small quantity of anethol.
This remaining trace was completely removed by dissolving
the mixture in a concentrated solution of iodine in acetone
and heating to boiling for a few minutes. Alcohol was then

1 J. prakt. Chem., 36, 275 (1845).

2 See also Ladentaurg : Ann. Chem. (Liebig), Supl. Bd. 8, Sg (1S72) ; I.audolph :
Ber. d. chem. Ges., 13, 144 (1880); and Klages : Ibid., 32, 1436 (1899).

Anethol and Its Isomers. 197

added to precipitate the anisoin, the mixture boiled with zinc
dust to remove the iodine, and filtered. Water added to the
filtrate precipitated an oil which was then further purified by
being washed with water, dried, and redistilled. The distil-
late would not unite with bromine and was consequently free
from anethol. Its boiling-point was determined as 2i2°.5-
213°. 5 C. (corr.) at 728 mm. barometric pressure. A com-
bustion gave the following results :'

0.1771 gram substance gave 0.5178 gram CO^, and 0.1538
gram H^O.

Calculated for

CioHiiO. Found.

c 80.00 79.73

H 9.33 9-65

From its boiling-point and percentage composition we must
conclude that this substance is parapropylanisol,

/OCH3

and, as it is formed by the reduction of anethol, it is probablj'-
the normal propyl compound. It was identical with one of
the compounds formed by heating anethol under pressure.'

ANISOIN.

Of the methods described for the preparation of anisoin the
two which have been especially recommended are : ( i ) The
polymerization of anethol by means of concentrated sulphuric
acid; and (2) The polymerization by means of a concentra-
ted solution of iodine in aqueous potassium iodide. There
are disadvantages to both of these methods. Unless the sub-
stances are left in contact for a long time, the anisoin formed
will retain included some unchanged anethol, as well as a cer-
tain quantity of the reagent, and will consequently be difiicult
to purify.

A method which on repeated trial in this work has been
found to give much better results is the one described below.
To a moderately concentrated solution of anethol in acetone,

1 This analysis was made by Mr. J. E. Teeple, to whom we wish here to express
our thanks.

2 This Journal, 19, S63.

198 Orndorff and Morton.

iodine is added until no more will dissolve. The mixture is
heated to boiling for a few minutes, after which the iodine is
removed by adding zinc dust, little by little, to the warm
solution until it becomes nearly colorless. This solution,
which must not be too concentrated, is then filtered slowly
into several times its volume of alcohol. The anisoin is thus
thrown down as a white powder, nearly pure.

No anisoin is formed by adding anethol to a concentrated
solution of iodine in alcohol even though the mixture be
heated to boiling.

Methyl Ether of Par acre sol.

When anisoin is distilled there is one product formed in so
small quantity that it has not hitherto been isolated. By dis-
tilling a large amount of anisoin (500 grams) and carefully
fractionating the resulting products, we obtained, together
with approximately 250 grams of anethol and 80 grams of iso-
anethol, about 20 grams of a liquid which distilled at lys''-

175° c.

This liquid doubtless still contained a slight trace of an-
ethol, but so little that it could scarcely be detected by testing
an ethereal solution with bromine. One-fiftieth part of a gram of
bromine imparted its color to an ethereal solution of i gram
of the substance. Hence it follows that the substance not
only does not contain anethol, but is itself a saturated com-
pound. Combustion analyses gave the following results :'

I. 0.2465 gram substance gave o. 1727 gram H^O, and 0.8084
gram CO,.

II. 0.1986 gram substance gave 0.1475 gram H^O, and
0.5719 gram CO,.

Calculated for

Fou

nd.

CsH

loO.

I.

II.

c

78.

68

78.38

78-54

H

8,

•19

7-79

8.25

0

13-

13

13-83

13.21

The analyses show that the compound is correctly repre-
sented by the formula CgHj„0.

This same compound was obtained in our previous investi-

1 These analyses were made by Mr. J. IJ. Teeple, to whom we wish here to ex-
press our thanks.

Anethol and Its Isomers. 199

gation by heating anethol under pressure, and analyses of
this product and molecular weight determinations showed it
to have the composition CgH,„0.

The percentage composition of the compound, its boiling-
point and its other properties, show it to be identical with the
methyl ether of paracresol described in the literature. It

/OCH3
consequently has the structural formula, CeH^C^ . It

is probably formed by the action of heat on the anethol (or
jQuid metanethol), resulting from the decomposition of anisoin
according to the following equation :

/OCH3 /OCH3

\CH = CHCH, \CH,

SUMMARY OF RESUI^TS.
Anethol and Fluid Metanethol.

The properties and reactions of anethol and fluid metan-
ethol have been given especial prominence in this work be-
cause, from the results of our earlier investigations, it seemed
probable that they were stereoisomers of the maleic-fumaric
acid type and would be represented by the two formulas :

/0CH3(/) /0CH3(/)

I. C,h/ and II. CeHX

^C— H \C— H

II II

H— C— CH3 H3C— C— H

It was to be expected that two stereoisomers of this type
would resemble each other very closely ; and that, with many
reagents, they would yield exactly the same products. Con-
sequently it was only after the two substances were very care-
fully examined and found to exhibit no differences whatever,
either in their own conduct or in the conduct of their deriva-
tives, that their complete identity was finally established.
The facts upon which this conclusion is based may be briefly
summarized as follows :

I. The physical properties of the two are identical. In

200 Orndorff and Morton.

odor, taste, boiling-point, melting-point, specific gravity, and
crystal form, the pure products exhibit no differences.

2. Both substances show exactly the same chemical con-
duct.

They yield the same dibromide and monobrom dibromide,
which conduct is a strong proof of their identity since stereo-
isomers of the formulas given above should not yield identical
derivatives of this character.

They yield the same hydrochloride, nitrosite, nitrosite an-
hydride, nitroso chloride, and picrate. This conduct might
not preclude the possibility of their being stereoisomers, but
it at least shows conclusively that they are structurally iden-
tical.

The identity in conduct of these compounds toward polym-
erizing and oxidizing agents might also be cited, but the
evidence seems already conclusive that anethol and fluid
metanethol are one and the same compound.

That the true character of fluid metanethol was not earlier
discovered is doubtless due to the difficulty of separating it
from the methyl ether of paracresol which is formed simul-
taneously with it. The presence of this impurity, even in
small quantity, lowers the melting-point of anethol many de-
grees and completely masks its odor.

Anethol Hydrochloride.

The conclusion of Saussure and Cahours that the product
formed by the action of hydrochloric acid on anethol is a
chemical compound of the formula Cj^Hj^CHCl, has been
confirmed by the results obtained in this investigation. One
molecule of anethol has been found to absorb exactly i mole-
cule of hydrochloric acid. The resulting product will not
take up bromine in the cold and hence contains no free an-
ethol. Moreover, by the action of alcoholic caustic potash, it
yields an alcohol addition-product of anethol,

C,„H,,O.C,H,OH,

the formation of which it is difficult to explain without as-
suming that the hydrochloride is first formed. Also, the fact
that anethol absorbs exactly i molecule of hydrobromic acid,

Anethol and Its Isomers. 201

with the formation of a saturated chemical compound, would
lead us to infer by analogy that its union with hydrochloric
acid is of the same character.

The Alcohol Addition-product of Anethol.

A compound of the formula Cj^Hj.O.C^H.OH is formed by
the action of alcoholic caustic potash on anethol hydrochlo-
ride. This compound has a pleasant mint-like odor. It is a
thin liquid, lighter than water, and is but slightly decom-
posed when distilled with steam. When distilled alone it
breaks down completely, yielding alcohol, anethol, and higher-
boiling products. It is not attacked by bromine in the cold.

Anethol Hydrobroniide.

Anethol rapidly absorbs hydrobromic acid gas until it has
taken up the amount required for the formation of a com-
pound of the formula Ci„H,,O.HBr. The hydrobromide is a
heavy oil closely resembling anethol hydrochloride in appear-
ance and conduct. When decomposed by alcoholic caustic
potash and distilled, it ^aelds as the chief products anethol
and isoanethol.

Pa rap ropyla n isol.

This compound results from the action of sodium on an
alcoholic solution of anethol, and is also formed as one of the
products when anethol is heated at a high temperature under
pressure. Analyses and molecular weight determinations
show its formula to be C,(|Hj^O ; and, since it is formed by the
addition of two hydrogen atoms to the anethol molecule, its
structure is most probably represented by the formula,

/OCH,

\CH,CH,CH3(/)

Anisoin.

It has been found most practicable to prepare anisoin by
adding anethol to a saturated solution of iodine in acetone
and heating the resulting mixture to boiling for a few minutes.
By this means the anethol appears to be rapidly and com-
pletely converted into anisoin.

202 Fraps.

When distilled, anisoin is completely decomposed, yielding
the compounds anetliol, isoanethol, and the methyl ether of
paracresol.

Methyl Ether of Paracresol .

One of the products formed by the breaking down of ani-
soin on distillation is a light, colorless oil, of pungent odor,
which boils at a temperature of 175" C. Thissan.e compound
has been previously obtained by the action of heat and pres-
sure on anethol. Perhaps, in its formation from anisoin, the
latter is first converted into anethol, and this is then partially
decomposed into the lower- boiling product. The physical
properties of this compound, as well as its percentage compo-
sition and molecular weight, identify it as the methyl ether of

/OCH3
paracresol, CgH,<(

Cornell University, Ithaca, N. Y.,
December, 1899.

THE SUPPOSED ISOMERIC POTASSIUM SODIUM
SUIvPHlTES.'

By Geo. S. Fraps.
INTRODUCTION.

The prevailing view in regard to the structure of sulphu-
rous acid is that it is asymmetrical and has the formula
H — SO2 — OH. From this formula it is theoretically possible
to derive two isomeric sodium potassium sulphites ; namely,
K— S0„— ONa and Na— SO,— OK. Descriptions of these
salts are on record. By neutralizing a concentrated aqueous
solution of acid potassium sulphite with sodium carbonate,
and precipitating with alcohol, A. Rohrig^ obtained fine lus-
trous crystals of the composition KNaSOj -\- 2H,0, which he
believed to be isomeric with crystals of the same composition
made in a similar manner from acid sodium sulphite and
potassium carbonate. The statement was probably based on
the assumed reactions :

1 This work was sugg-ested by Prof. Ira Remsen, and conducted under his direc-
tion in the laboratory of the Johns Hopkins University.

2 J. prakt. Chem. [2], 37, 250.

Isomeric Potassium Sodium Sulphites. 203

2H— SO, — OK + Na.CO, =: 2Na— SO — OK + CO, + H,0 ;
2H— SO — ONa + K.CO3 - 2K— SO,— ONa + CO, + H,0.

H. Schwicker' prepared the salts in a similar manner, but,
instead of precipitating with alcohol, he evaporated the solu-
tions in a desiccator over sulphuric acid. The crystals con-
tained different amounts of water of crystallization. The one
from acid potassium sulphite and sodium carbonate separated in
crystals having the composition NaKSOj -j- 2H,0 ; the crys-
tals of the other, from acid sodium sulphite and potassium
carbonate, had the formula NaKSOj + H,0.

By the aid of the reaction between ethyl iodide and a sul-
phite, in which the metal united to the sulphur is replaced
by ethyl, thus :

C,H J +Na — SO, -ONa = C,H — SO — ONa + Nal ,

we might be able to determine if the salts described above
are isomeric or identical, since, if different, the one should
yield a sodium ethjdsulphonate, the other a potassium ethyl-
sulphonate :

C,HJ -h K— SO,— ONa =C,H — SO — ONa + KI ;
C,H J + Na— SO,— OK = C,H,— SO,— OK + Nal ;

or more correctly, the double salt 4C,H,S03Na + KI could be
extracted from the reaction-product of the first, and the salt
4C,H,S03K + Nal from that of the other.

According to Schwicker, when the sodium potassium sul-
phite made from acid sodium sulphite and potassium carbon-
ate is heated in aqueous solution in a sealed tube with ethyl
iodide and the product recrystallized from alcohol, it contains
sodium and potassium in the ratio Na : K : : 4 : i, correspond-
ing to the double salt 4C,H,S03Na + KI. The salt from
acid potassium sulphite and sodium carbonate under the same
conditions yielded a product containing Na : K : : i : 4, corre-
sponding to the double salt 4C,H,S03K + Nal. This indi-
cates that isomeric salts have been prepared, having the for-
mulas K— SO,— ONa and Na— SO,— OK. Schwicker states
further that, by boiling the isomeric sulphites with ammonium

1 Ber. d. chetn. Ges., 32, 172S.

204 Fraps.

poh'sulphide, they are converted into isomeric thiosulphates,
which, when heated with ethyl bromide (Bunte's reaction),
yield, the one the sodium salt, C^H^SjO^Na + H,0, the other
the potassium salt, C^H.S^OjK.

More recently this work has been repeated by K. Earth' in
the course of an investigation on the complex salts of sulphur-
ous acid. The acid sulphite was lormed b}^ passing sulphur
dioxide into a strong solution of sodium (or potassium) hy-
droxide, and neutralized by the requisite quantity of a solu-
tion of potassium (or sodium) hydroxide. Alcohol precipita-
ted both salts as water-free crystals, not the cr3-stals

NaKSO, -f- 2Hp,

of Rohrig. Under ordinary conditions, the crystals formed by
evaporation over sulphuric acid in a desiccator were water-
free, but, when cooled, crystals separated which had the
composition of those obtained by Schwicker.

Earth heated the equally concentrated solutions of the
water-free salts — the concentration is not given — with ethyl
iodide in a sealed tube at 130° for three hours, evaporated to
dryness, extracted the residue with 97 per cent alcohol, and
recrystallized from 99 per cent alcohol. The product was
analyzed by igniting with sulphuric acid, and determining the
sulphuric acid in the residue, from which the ratio Na : K was
calculated. The potassium sodium sulphite from acid sodium
sulphite and caustic potash yielded a product containing
Na : K : : I : 1.3 (mean of two preparations) ; theory requires
for the salt 4C,H,S0,Na + KI, Na : K : : 4 : i . The salt from
acid potassium sulphite and sodium hydroxide yielded a prod-
uct containing Na : K : : i : 2.9 (mean of two) instead of
Na : K : : I : 4 as required by the theory. The two sodium
potassium sulphites yielded different products, and must
therefore be different.

Earth explained the deviation of the results from the theoret-
ical in terms of the theory of electrol3'tic dissociation. He
showed that the salts dissociate into three ions. When the ions
K,Na,S03, from the salt KSO^ONa, for example, are caused
to reunite, as by evaporation of the solution, or precipitation

1 Ztschr. phys. Chem., 9, 77.

Isomeric Potassium Sodium Sulphites. 205

with alcohol, there is no reason to suppose the salt KSO._,ONa
to be formed again, but rather a mixture of the salts
NaSO.OK, KSO.ONa, Na.SO,, and K,SO„ and the pure salt
KSOjONa could not be obtained. Again, when the reaction
betweed the ethyl iodide and the salt has taken place, the
potassium iodide and the sodium ethylsulphonate must be dis-
sociated to some extent, and potassium ethylsulphonate and
sodium iodide must be formed when the solution is evapora-
ted to dryness. The alcohol from which the salt is recrystal-
lized must exert some influence on its composition also.
Hence one could not expect the ratio of sodium to potassium
to agree with that required by theory. Barth states that " an
infallible conclusion as to the different constitution of the sul-
phites cannot be drawn from the results obtained, but only
that in one solution more molecules of KSO„ONa were pres-
ent, in the other more molecules of NaSO^OK, and hence the
probability of the isomerism of the solid bodies."

The conclusion does not appear to be accepted. Hantzsch'
asserts that structural isomerism is unknown among inorganic
compounds. A Sabanejeff* observes that the isomerism of
the potassium sodium sulphites can by no means be regarded
as proved.

The stability of the salts appears incompatible with the
theory of electrolytic dissociation, since they dissociate into
three ions. If dissociation is conceived as a dynamic condi-
tion, in which the molecules are in a constant vibration of de-
composition and recombination, it is difl&cult to see how the
salts K — SO, — ONa and Na~SO,— OK, supposing them to
exist as solids, could long retain their individuality even in
concentrated solutions. In a certain time the uudissociated
portion of the salts must assume a condition of equilibrium of
the salts K.SOj, Na.SO^, KNaSOj, which would be the same
whether sodium potassium sulphite or potassium sodium sul-
phite were the starting-point. That is to say, isomeric salts
of such a nature could not remain different in aqueous solu-
tion, even if they exist in the solid state.

1 Anu. Chem. (Liebig), 392, 342 ; 296, 100, in.

2 Ztschr. anorg. Chem., 17, 4S1.

2o6 Fraps.

The same objection applies to the reaction used to prove
that the two salts are different, or Guldberg and Waage's law
of mass action ma)^ be applied. Supposing the following re-
actions to take place :

C,HJ + KSO.ONa = C,H,SO,ONa-f KI ;
C,H J -f NaSO.OK — C,H,SO,OK -f Nal.
The reaction

C,H,SO,ONa + KI Zr C,H,SO,OK + Nal

must surely be a reversible one, and the condition of equilib-
rium would be the same from either starting-point ; at 130°
the adjustment would not take long.

These considerations throw doubt upon the work before
cited, and it was repeated. Before going into details, a brief
summary of the experiments will be given. Four sets of the
double salts were prepared, under conditions judged most favor-
able to the appearance of isomerism, one member of the set
from acid sodium sulphite and potassium carbonate or hydrox-
ide, the other from acid potassium sulphite and sodium carbonate
or hydroxide. The salts in each set were made under exactly
similar conditions and at the same time, with the exception of
set I, as hereafter noted. In set I the salts were not ana-
lyzed ; in set II they were slightly different in composition ;
and in sets III and IV they had practically the same compo-
sition.

The two salts, which it was thought might be isomeric,
were heated with ethyl iodide, the products extracted with
alcohol and analyzed, the supposed isomers being subjected
to conditions as nearl}'- identical as possible. Seven experi-
ments were thus made, in which the strength of alcohol, time
of heating, etc., were varied slightly. If the salts were iso-
mers, analysis should show a difference in the ratio of sodium
to potassium ; in none of the experiments was there an}^ de-
cided variation. It is believed that the conditions were as
favorable for the isomerism to reveal itself as it was possible
to make them. The writer therefore feels justified in making
the statement that we have no evidence that isomeric potas-
sium sodium sulphites exist.

Isomeric Potassium Sodium Sulphites. 207

The table shows the ratio of sodium to potassium as found
by analysis of the double sulphonate prepared from the two
salts.

Na

NaSOjOK.

KSOjONa.

: K required by theory . •

..1:4

4 : I

' ' found by Barth . .

.. I : 2.9

I : 1.3

' ' Experiment

I

I : 1.57

I : 1.40

II

I : 1.43

I : 1-37

III

I : 1.89

I : 2.17

IV

I : 1-59

I : 1-57

V

I : 2.09

I : 2.10

VI

I : 2.06

I : 2.01

VII

I : 1.82

I : 1.73

The variation in the ratio Na : K in the different experi-
ments is ascribed to the difference in the conditions. The
stronger the alcohol used, the wider the ratio. Recrystalli-
zation from alcohol increased the ratio also, as may be seen
by comparing Experiments I, II, and IV, in which the sul-
phonate was not recrystallized, with Experiments III, V, VI
and VII, in which it was recrystallized from alcohol. The
slight variation between the two members of a set was to be
expected and is probably due to the alcohol.

EXPERIMENTAL.

Experiment I. — Sulphur dioxide was passed into a cooled
solution of 1 1.5 grams of potassium carbonate in 75 cc. water
until the weight gained was that required for the formation of
acid potassium sulphite. Nine grams of sodium carbonate
were added, air drawn through to remove carbon dioxide,
and the salt precipitated with alcohol. It was not analyzed.

Ten grams of the above salt, 11 grams ethyl iodide, and 15
cc. water were heated two and a half hours in a sealed tube to
i30°-i40°, and the tube allowed to cool over night. The
solution was evaporated to dryness, and the product extracted
with laboratory alcohol. It was not recrystallized.

Analysis showed the ratio of sodium to potassium to be
Na : K : : I : 1.57. Theory for 4C,H,S03K + Nal, i : 4.

(i) 0.3381 gram substance, ignited with sulphuric acid,
gave 0.1922 gram sulphates, yielding 0.2771 gram barium
sulphate.

2o8 Fraps.

Per cent SO3 in sulphates = 49.52. Na : K : : i : 1.54.

(2) 0.2848 gram substance gave 0.1612 gram sulphates,
yielding 0.2320 gram barium sulphate.

Per cent SO3 in sulphates = 49.43- Na : K : : i : 1.59.

Proceeding exactly as above, and performing the operations
at the same time and under the same conditions, but using a
solution of 9 grams sodium carbonate in 32 cc. of water, and
adding 11.5 grams of potassium carbonate, the supposed iso-
meric salt was prepared. It was treated with ethyl iodide
under the same conditions, at the same time as the above, the
product extracted with the same alcohol, and analyzed. The
ratio of sodium to potassium was i : 1.40 ; a slight difference,
but no evidence of isomerism.

(i) 0.3892 gram substance gave 0.21 17 gram sulphates,
yielding 0.3067 gram barium sulphate.

Per cent SO3 in sulphate = 49.77 Na : K : : i : 1.38.

(2) 0.2858 gram substance gave 0.1545 gram sulphates,
yielding 0.2235 gram barium sulphate.

Per cent SO, in sulphates == 49.69. Na : K : : i : 1.41.

In the experiment above described, the two salts were pre-
pared in solution of different concentrations, for the reason
that it seemed to be desirable to use as concentrated solutions
as possible, and acid potassium sulphite is less soluble than
acid sodium sulphite. In succeeding experiments the salts
are prepared in solutions of equivalent concentration.

Experiment II. — The salts were prepared as in Experiment
I, with the exception that the solutions were of different con-
centration, i. (?., 23 grams of potassium carbonate in 120 cc.
water, and 18 grams of sodium carbonate in the same quan-
tity.

Analysis of the salts :

{a) Salt from acid potassium sulphite and sodium car-
bonate :

(i) 0.3344 gram substance, with sulphuric acid, gave
0.3657 gram mixed sulphates, which yielded 0.5403 gram
barium sulphate. Na : K : : i : 0.94.

(2) 0.2899 gram substance gave 0.3180 gram sulphates,
yielding 0.5403 gram barium sulphate. Na : K : : i : 0.99.

Isomeric Potassium Sodium Sulphites. 209

{b) Salt from acid sodium sulphite and potassium carbonate :

(i) 0.4505 gram substance gave 0.4756 gram sulphates,
yielding 0.71 19 gram barium sulphate. Na : K : : i : 0.72.

(2) 0.5432 gram substance gave 0.5762 gram sulphates,
yielding 0.S614 gram barium sulphate. Na : K : : i : 0.74.

The ratio of sodium to potassium in the two salts is differ-
ent. The analyses show the crystals to be water-free.

Ten grams of the salt {a), from acid potassium sulphite
and sodium carbonate, 11 grams ethyl iodide, and 21 cc.
water, were heated three hours in a sealed tube to i3o°-i40°.
The solution was evaporated to dryness, the product extracted
with laboratory alcohol, and analyzed. The ratio Na : K was
found to be I : 1.43.

(i) 0.188 1 gram substance, ignited with sulphuric acid,
gave 0.1004 gram sulphates, which yielded 0.1452 gram
barium sulphate.

Per cent SO3 in sulphates == 49.67. Na : K : : i : 1.44.

(2) 0.2580 gram substance gave 0.1389 gram sulphates,
yielding 0.2010 gram barium sulphate.

Per cent SO3 in sulphates =: 49.70. Na : K : : i : 1.41.

Ten grams of salt {b) was treated as above and at the same
time. The ratio of Na : K in the product was i : 1.37. Salt
(a) was not different from salt {b).

(i) 0.1500 gram substance gave 0.0798 gram sulphates,
yielding 0.1162 gram barium sulphate.

Per cent SO3 in sulphates = 50.01 Na : K : : i : 1.23.

(2) 0.2179 gram substance gave 0.1164 gram sulphates,
jaelding 0.1679 gram barium sulphate.

Per cent SO3 in sulphates = 49-54. Na : K : : i : 1.51.

The composition of the two products was practically the
same.

It will be noted that laboratory alcohol of unknown strength
w^as used in the foregoing experiments. The strength of the
alcohol must have some effect on the composition of the prod-
uct, since that double salt would crystallize out that was most
insoluble under the conditions of the experiment. For this

2IO Fraps.

reason it was determined to repeat the work, using alcohol of
different strength.

The double sulphites used in the experiments about to be
described were prepared as follows : A solution of caustic
potash was prepared, containing 172.2 grams of caustic pot-
ash in a liter, the strength being determined by titration with
standard acid, and also a solution of caustic soda containing
124.2 grams per liter. 100 cc. of the solution were cooled
with ice-water, and sufficient dry sulphur dioxide (from
sodium sulphite and sulphuric acid) passed in to form the
acid salt, controlling the amount of sulphur dioxide by weigh-
ing. In case an excess of sulphur dioxide was absorbed, the
volume of the solution containing the required amount of the
proper alkali was added, keeping the liquid cool. The acid
sulphite so formed was neutralized with the requisite volume
of the other alkali and the double salt precipitated imme-
diately with 500 cc. of alcohol, washed with alcohol, and
dried on drying-paper. It is believed that these conditions
are most favorable to the production and retention of the isom-
erism, if it exists.

Experiments III a7id IV. — Salts were prepared as just de-
scribed, and analyzed.

{a) From acid potassium sulphite and caustic soda :

(i) 0.5150 gram substance gave 0.5705 gram sulphates, and
yielded 5 X 0.1637 gram K^PtCl^.

KjO = 30.69 per cent. Na : K : : i : 0.86.

(2) 0.5200 gram substance gave 0,5759 gram sulphates, and
5 X 0.1664 gram K^PtClg.

K,0 — 30.85. Na : K : : I : 0.87.

(($•) Salt from acid sodium sulphite and caustic potash.

(1) 0.5409 gram substance gave 0.5956 gram sulphates, and
yielded 5 X 0.1703 gram K^PtCle-

K,0 — 30.40. Na : K : : I : 0.85.

(2) 0.5080 gram substance gave 0.5585 gram sulphates,
and yielded 5 X 0.1583 gram K.PtCl,.

K,0 — 30.08. Na : K : : I : 0.84.

Isomeric Potassium Sodium. Sulphites. 211

The salts had practically the same composition and were
anhydrous.

Experiment III. — Ten grams of each of the above salts, 21
grams water, and 11 grams ethyl iodide, were heated in sealed
tubes for three hours at i30°-i40°. The tubes cooled over
night. Their contents were then evaporated to dryness, ex-
tracted with 500 cc. of alcohol, sp. gr. 0.839, and recrystallized
from 250 cc. of alcohol of sp. gr. 0.7975.

Analysis of the products .

(a) From salt (^).

(i) 0.2421 gram substance gave o. 1325 gram sulphates, and
yielded 0.2546 gram K^PtCle.

K,0 = 20.3. Na : K : : I : 1.79.

(2) 0.7376 gram substance gave 0.4050 gram sulphates, and
j'ielded 5/2 X 0.3206 gram KjPtCU.

K„0 = 20.98. Na : K : : I : 1.99.

{b) From salt {b).

(i) 0.2753 gram substance gave 0.1526 gram sulphates, and
yielded 0.3092 gram K,PtCl,.

K,0 = 21,68. Na: K : : I :2.i4.

(2) 0.5876 gram substance gave 0.3256 gram sulphates, and
yielded 5/2 X 0.2675 gram K^PtCle.

K,0 = 21.97. Na : K : : I : 2.21.

This experiment was supposed to be as nearly as possible
a repetition of Earth's, but it did not confirm his results.

Experime7it IV. — Six grams of the above salts, 7 grams
ethjd iodide, and 12 grams water were heated to i30°-i36° for
three hours. The contents of the tube were evaporated to
dryness the same day, and extracted with alcohol of sp. gr.
0.804. The product was not recrystallized.

Analysis of the products :

(a) From salt {a).

1. 02 1 1 gram substance gave 0.5557 gram sulphates, which
gave 5 X 0.2057 and 5 X 0.2049 gram K^PtCl^.

» ( 19.40 1 I : 1.59

{b) From salt {b).

212 Fraps.

1. 1 822 gram substance gave 0.6421 gram sulphates, which
gave 5 X 0.2370 and 5 X 0.2363 gram K^PtCl,.

■ \ 19-30 1 I : 1-57

The ratio of sodium to potassium is the same in the prod-
ucts from both salts. It will be noted that the ratio is differ-
ent from that in Experiment III, which is i : 1.89 and i : 2.21.
Recrystallization from stronger alcohol increases 'he ratio.

Experiments V, VI, a?id VII. — The supposed isomeric
potassium sodium sulphites were prepared exactly as for Ex-
periments III and IV.

Analysis of the salts :

{a) Salt from acid potassium sulphite and caustic soda.

(i) 0.5527 gram substance gave 0.6090 gram sulphates,
yielding 5 X 0.1709 gram K.PtCl^.

K,0 = 29.85. Na : K : : I : 0.82.

(2) 0.5051 gram substance gave 0.5588 gram sulphates,
yielding 5 X 0.1578 gram K^PtCle-

K,0 — 30.08. Na : K : : I : 0.83.

{b) From acid sodium sulphite and caustic potash.

(i) 0.5035 gram substance gave 0.5565 gram sulphates,
yielding 5 X 0.1574 gram K.PtCl,.

K„0 — 30.18. Na : K : : I : 0.84.

(2) 0.5167 gram substance gave 0.5727 gram sulphates,
5 X 0.1607 gram K.PtCl,.

K,0 = 30.02. Na : K : : I : 0.82.

The salts were anhydrous and had practically the same
composition.

Experiment V. — The operation was carried on the same as
Experiment III, and under the conditions there described.

Analysis of the products :

(a) From salt (a).

0.3275 gram substance gave 0.1802 gram sulphates, yield-
ing 0.3626 gram K^PtCU.

K5O := 21.37. Na : K : : I : 2.09.

(d) From salt {d).

Isomeric Potassiwm Sodium Stdphites. 213

0.21 15 gram substance gave 0.1076 gram sulphates, yield-
ing 0.2169 gram K^PtCl^.

K,0 = 19.80. Na: K : : I : 2.10.

There is no evidence of isomerism ; the ratio of sodium to
potassium is nearly as in Experiment III.

Experiment VI. — Ten grams of the double sulphites de-
scribed above, 11 grams ethyl iodide, and 20 grams water,
were heated as in the preceding experiment. The contents
of the tube w^ere evaporated to dryness the same day, the
residue extracted with 500 cc. alcohol (sp. gr. 0.803) and re-
cr)'stallized from 250 cc. alcohol of 0.795 sp. gr.

Analysis of the products :

(a) From salt (a).

0.8606 gram substance gave 0.4710 gram sulphates, and
yielded 5 X 0.1887 gram K.PtClg.

K,0 = 21.16. Na:K : : I : 2.06.

{b) From salt (3).

0.2361 gram substance gave 0.1297 gram sulphates, and
yielded 0.2602 gram K^PtCl^.

K,0 = 21.28. Na : K : : I : 2.01.

Experiment VII. — Ten grams of the double sulphites de-
scribed above, 1 1 grams ethyl iodide, and 20 grams water,
were heated in sealed tubes at the same time as Experiment
III. The contents of the tubes were evaporated to dryness
the same day. The product was extracted with alcohol of
0.808 sp. gr. and recrystallized from alcohol of 0.803 sp. gr.

Analysis of the products :

\a) From salt {a).

(i) 0.91 16 gram substance gave 0.4978 gram sulphates,
yielding 5 X 0.19 10 gram K^PtCl^.

K,0 — 20.23. Na : K : : I : 1.78.

(2) 1.0257 grams substance gave 0.5602 gram sulphates,
yielding 5 X 0.2180 gram K^PtCle.

K,0 — 20.25. Na: K : : I : 1.86.

(3) From the salt {b).

214 Tingle and Tingle.

(i) 0.9551 gram substance gave 0.5123 gram sulphates, of
which 0.4632 gram gave 5 X 0.1768 gram K^PtCle.
K,0 = I9-77. Na : K : : i : 1.75.
(2) 1.2675 gram substance gave 0.6916 gram sulphates,
yielding 5 X 0.2617 gram K„PtCl6.

K^O = I9-93- Na : K : : i : 1.70.
No evidence of isomerism.

Conchision and Summary .

It has been stated that two isomeric potassium sodium sul-
phites exist, which can be distinguished from each other by their
action upon eth}^ iodide, the one yielding a salt approaching
the composition 4C5H5S050Na + KI, the other approaching
4C,H,S0,0K + Nal.

Under the most favorable conditions that could be devised,
and working on salts supposed to be isomers, in these experi-
ments practically no difference could be observed in the com-
position of the products obtained by the action of ethyl
iodide on the salts. In seven experiments only slight varia-
tions could be observed, and this could be explained by
changes in the strength of the alcohol.

There appears, therefore, to be no evidence that isomeric
potassium sodium sulphites exist.

Chemical Laboratory,

Johns Hopkins University,

December, 1898.

CONDENSATION COMPOUNDS OF AMINES AND
CAMPHOROXALIC ACID.

FIFTH COMMUNICATION ON THE INTERACTION OF ETHYLIC

OXALATE AND CAMPHOR.'

By J. Bishop Tingle and Alfred Tingle.

THEORETICAL.

In the preceding paper on this subject {loc. cH.) we de-
scribed three compounds obtained from aniline and camphor-
oxalic acid, to which we assigned the formulae

1 This Journal, 21, 23S (1S99) ; Ibid., 20, 318 (1S9SI ; Ibid., 19, 393 (1897) ; J. Chem.
Soc. (London), 57, 652 (1890).

Amines ajid Camphor oxalic Acid. 215

C„H,

and

A-

C.CO.OH
NH.C.H, '

/9 '■

C.CO.ONH
NH.C.H,

C.H,

.C : CH

""^co nh.c„h/

and designated them phenylcamphoformeneaminecarboxylic
acid, anilinephenylcamphoformeneaminecarboxylate, andphe-
nylcamphoformeneamine, respectively. We have now obtained
a number of other condensation compounds of camphoroxalic
acid and its ethylic salt with various aliphatic and aromatic
amines, and have gathered further evidence in favor of the
above formulae. The majority of the compounds from ali-
phatic amines will be described in a subsequent communica-
tion and will only be referred to here in so far as is neces-
sary to elucidate theoretical points.

By the action of a-naphthylamine on camphoroxalic acid
(as sodium salt), in alcoholic solution, at 100°, under pressure,
a compound is obtained crystallizing from benzene in well-de-
veloped, transparent, amber-colored crystals ; at ioo°-i05°
these gradually become opaque and finally change to a light-
brown powder, which, like the crystals, melts and decomposes
at 170°. The compound has well-marked acidic properties
and readily dissolves in a solution of sodium carbonate ; it
gives no coloration with ferric chloride and alcohol. This
substance is strictly analogous with the first of the aniline
compounds mentioned above, and is therefore termed a-naph-
thylcamphof ormeneaminecarboxy lie acid ,

/C : C.COOH
C,H, / I I

\C0 NH.C,„H,

the crystals contain 0.5 molecule benzene of crystallization.
The corresponding derivative of /^-naphthylamine is formed
in an analogous manner ; it quickly dissolves in toluene, but
in benzene, although its solubility is ultimately considerable,
it dissolves very slowly ; the supersaturated solution formed
on cooling is relatively stable, as crystals are deposited only
gradually. The compound is obtained from either solvent in
bright-yellow needles melting and decomposing at 173°. In

2i6 Tingle and Tingle.

its acidity and other properties it closely resembles the
«-naphthyl derivative.

Orthophenylenediamine readilj'^ condenses with sodium or
potassium camphoroxalate, in equimolecular proportion, when
heated at ioo°, in alcoholic solution, under pressure. The
yield is extremely good. The compound has the formula
CjgHjjiNjOj. It is readily soluble in benzene, and is deposited
in bright-yellow needles melting at 246". It dissolves to some
extent in hot water, in boiling hydrochloric acid, and sodium
hydrate solution, all of which are practically without action
on it. With concentrated sulphuric acid, at the ordinary
temperature, a red solution is obtained resembling that pro-
duced by a crystal of potassium bichromate. After remain-
ing during eight days without heating the compound is re-
covered unchanged on dilution, except for the formation of a
little resinous matter. The same substance is also formed from
orthophenylenediamine and ethylic camphoroxalate under sim-
ilar conditions. The properties of the compound characterize
it as a quinoxaline derivative with one of the following formulae :

/C : C C.OH /C : C CO

(I) C„H,,< I I II ; (2) C,H./ II I ;

\C0 NH N \C0 NH NH

\/ \/

CeH, C,H,

/CH.C C.OH /CH.C CO

(3) C,H,/ I II II ; (4) C,H,/ I II I ;
\C0 N N ^CO N NH

C.H, C,H,

The relationship between i and 3, and 2 and 4, respectively,
is similar to that between the enolic and ketolic forms of cam-
phoroxalic acid, and may, for present purposes, be ignored,
the choice thus falling between i and 2. From analogy with
the preceding compounds we should expect to obtain from
the alkali camphoroxalate as primary, intermediate product a
compound of the formula

/C : C.CO.O(KNa)

CsH,,^

CO NH.C.H.NH,

Amines and Caniphoroxalic Acid. 217

then, by the further elimination of water this should give rise

.C : C C.O(KNa)

to the substance C^H^X II 1 1 > which on

^CO NH.C,H,N

acidification would produce the compound i. Ethyliccamphor-
oxalate should, in an analogous manner, eliminate water and
alcohol successively, and yield the compound 2. We must there-
fore conclude either that one of these is unstable and immedi-
ately changes into the other, or that the excess of diphenylamine
employed in the preparation of the ester condensation-product
has hydrolyzed the intermediate product,

/C : C . COC.H,
C«H. / I I II
\C0 NH N

to the compound i. We regard the former view as the more
probable, since otherwise it is difficult to understand why the
ethylic camphoroxalate itself should not have been hydro-
lyzed. But this would have led to the formation of a phenyl-
enediamine salt which, as no acid was used in the purification,
should have been isolated. A second argument, tending in
the same direction, is based on the fact that meta- and para-
phenylenediamine, under similar conditions, did not hydrolyze
the ester at all, although, from their total failure to react in
any way, they were present in larger excess than was the
ortho-compound. Finally, the yield from the ortho-amine is
relatively large, and is scarcely affected by reducing the quan-
tity of amine to somewhat below i molecular proportion.

Two substances are formed by the interaction of semicarb-
azide and potassium camphoroxalate in presence of alcohol,
under pressure, at 100°. For the present we will term them
simply the a- and /3-semicarbazides of camphoroxalic acid.
They are separated by means of their different solubility in
ether ; the or-compound, which readily dissolves, is deposited
from acetone in small white needles, melting and decompo-
sing at 218°. It is soluble in a warm solution of sodium car-
bonate, is reprecipitated in a gelatinous condition on acidifi-
cation, and gives no coloration with ferric chloride and alco-

2i8 Tingle and Tingle.

hoi. The /5-derivative is formed in smaller quantity than its
companion ; it is not soluble in the ordinary neutral organic
media, but slowly dissolves in boiling glacial acetic acid, and
is gradually deposited from the solution, on the addition of
alcohol, in colorless, microscopic needles aggregated into
characteristic cubical forms ; it melts and decomposes at 209°-
210°. The substance resembles the or-derivative in its be-
havior towards ferric chloride and sodium carbonate, but from
solution in the latter, acids precipitate the ^-compound. Both
bodies agree closely in their content of carbon and hydrogen,
which is that required for semicarbazylcamphoformene-

^C : C.CO.OH
carboxylic acid, C,H,^^ | | ' ; pending

\C0 NH.NH.CO.NH,
further experimental evidence we shall abstain from discuss-
ing their relationship and constitution.

We have previously shown {loc. cit.) that at 130° ethylic
camphoroxalate combines with two molecular proportions of
aniline forming phenylcamphoformeneaminecarboxylic ani-

,C : C.CO.NH.C.H,
lide, C-H,^^ II .At 100°, under pressure,

\C0 NH.C.H,
in alcoholic solution, ethylic camphoroxalate and aniline,
or preferably aniline hydrochloride and potassium hydroxide,
in the above proportions, yield ethylic phenylcamphoformene-

,C : C.CO.OC.H,
aminecarboxylate, C^H;^<^ | | .It readily crys-

\C0 NH.C.H,
tallizes from benzene in white, microscopic needles melting
and decomposing at 158^-160°. By the action of alkalies the
corresponding acid (m. p. 174°) is obtained. It has been
previously prepared by us from aniline and camphoroxalic
acid or sodium camphoroxalate.

/i-Naphthylamine resembles aniline in its behavior towards
ethylic camphoroxalate and yields ethylic /:/-naphthylcampho-

yC : C.CO.OC.H,
formeneaminecarboxylate, CgH,^<^ | | . This is

^CO NH.C.^H,
somewhat sparingly soluble in boiling benzene, and is de-
posited in colorless microscopic needles which soften at about

Amines and Camphoroxalic Acid. 219

160', and melt and decompose at 174° when rapidly heated,
otherwise at a lower temperature. The compound is insolu-
ble in hot water, and, except for a slight superficial yellow
color, unchanged by boiling with a solution of sodium car-
bonate.

Semicarbazide hydrochloride and ethylic camphoroxalate
react in dilute alcoholic solution, at the ordinary temperature,
in the presence of potassium acetate. The same product is
formed at 100° if potassium hydroxide, in quantity slightly
less than is sufl5cient to liberate the base, is substituted for the
acetate.

Ethylic semica rbazylcaviphoforineneca rboxylate ,
,C : C.CO.OC,H,
Q.^^/ I I , readily dissolves in ethylic

^CO NH.NH.CO.NH,
acetate, chloroform, and ether ; moderately in benzene and
acetone, and is practically insoluble in ligroin. It crystallizes
from ethylic acetate in colorless needles melting at 202°.
When prepared at 100° with potassium hydroxide in the man-
ner referred to above, a second compound is formed in small
quantit3^ This is very sparingly soluble in boiling ether, and
in water at the ordinary temperature. It crystallizes in col-
orless needles and melts at 255°.

Ethylic camphoroxalate also condenses with ammonia,
methylamine, and ethylamine. The compounds formed differ
in type from those described above, but resemble the phenyl-
camphoformeneaminecarboxylic anilide,

/C : C.CO.NH.C.H,

prepared by heating ethylic camphoroxalate and aniline at
130", and described by us in the previous paper {loc. cit.).
The conditions under which they are obtained are similar to
those employed for the production of the above ethylic
yS-uaphthylcamphoformeneaminecarboxylate, and, together
with the compounds themselves, will be fully detailed in a
subsequent communication. At present we merely desire to
draw attention to the striking distinction in behavior between
the two classes of amines. That this difference is not due

220 Tingle and Tingle.

simply to the "aromatic" or " aliphatic" nature of the bases
is shown by the behavior of semicarbazide. We regard the
difference as being dependent primarily on the basicity of the
amine, the strongly basic ones being capable of attacking the
carbethoxyl group (CO.OC^HJ at lOo", aniline only at 130°,
whilst the naphthylamines, which are still more feebly basic,
are either incapable of reacting with it at all under the con-
ditions we have tried, or at any rate cannot do so at tempera-
tures below that at which ethylic camphoroxalate itself suffers
decomposition.

We have hitherto failed to obtain condensation compounds
with ethylic camphoroxalate or potassium camphoroxalate,
and ethylaniline, dimethylaniline, meta- and paraphenylene-
diamine, and urea, whilst ethylic camphoroxalate did not re-
act with «r-naphthylamine and dimethylamine. We have no
explanation to offer for the failure with a'-naphthylamine.
Perhaps in the case of urea the cause is to be sought in its
comparatively feeble basic properties. The inhibition of the
reaction in the case of the two phenylenediamines is doubtless
due to the relative difficulty experienced in producing rings
of seven and eight members,

/C.N.C.C.C C,„H,p : C C

C,„H.,0:C< I I and

'\

N.C.C C N N,

^ — -' I CC '

as compared with the six-membered ring,

.C.N.
C,„H.,0 : C/ >C.C.

\n.c/ >c,

J — CC/

which is actually formed in the case of orthophenylenedi-
amine.

The failure with dimethylaniline is only what would be ex-
pected from the nature of the reaction, since, being a tertiary
base, there is no hydrogen to form water with the hydroxyl of
the ethylic camphoroxalate. The case is otherwise, how-
ever, with ethylaniline and dimethylamine. We shall re-

Amines and Carnphoroxalic Acid. 221

serve the discussion of the latter for a subsequent communi-
cation and at present confine ourselves to the former.

In our previous paper on this subject {loc. cit.) we sug-
gested two formulae for phenylcamphoformeneaminecarboxylic
acid (m. p. 174°); viz.,

/C : C.CO.OH /C — CH.CO.OH

CaH, / I I and C,H, / | \ |

\C0 NH.C.H. \C0 N.CeH,

'6 5

expressing our preference for the former. We have obtained
cr5'stalline compounds from the corresponding amine (m. p.
166°) with benzoyl chloride, phenylsulphonic chloride, and
acetic anhydride. Should further investigation prove these
to be simple acyl derivatives the first formula would be estab-
lished, but in this case there is no very obvious reason why a
secondary amine should not react like aniline. The second
of the above formulae, whilst furnishing a satisfactory explana-
tion of the failure of the group R^NH to react, does not lead
us to expect the production of a benzoyl, phenylsulphonyl, or
acetyl derivative. Pending further experimental evidence we
prefer not to commit ourselves to a decided opinion. It is
possible that the chlorides cause cission of the ring, or that,
somewhat on the lines of Bischoff's " dynamical theory,"
stereo-conditions of the two radicals linked to nitrogen pre-
vent the reaction. We hope later to be able to throw light on
this point. The compound from benzoyl chloride and phenyl-
camphoformeneamine mentioned above crystallizes from ben-
zene in prisms resembling those of potassium nitrate, and
forming characteristic cruciform aggregates. It melts at
i6o°-i6i°. With phenylsulphonic chloride the amine yields
a colorless, crystalline compound, which melts at 133" and is
insoluble in a solution of sodium hj^droxide, indicating the
secondary nature of the original amine.

Phenylcamphoformeneamine and acetic anhydride also yield
a crystalline product which, after being well drained on tile,
melted at 134°. It was, however, contaminated with resinous
matter, and repeated recrystallization from alcohol, or prefer-
ably ethylic acetate andligroin, failed to produce a separation,
as each crystallization caused some decomposition.

222 Tingle and Tingle.

EXPERIMENTAL.
Camphoroxalic Acid and a-Naphthylamine.

Camphoroxalic acid (4.4 gram := i mol.), ar-naphthylamine
(1.4 grams=:o.5 mol.), sodium hydrate (0.8 gram = i mol.),
and 95 per cent alcohol (about 50 cc.) were heated in a pres-
sure bottle at 100°, during four hours. The alcohol was then
evaporated on the water-bath, and the residue treated with
water, acidified with dilute sulphuric acid, and extracted with
ether. The ethereal solution, after drying with calcium chlo-
ride, was distilled, and the residue crystallized twice from
benzene. The yield of a-naphthylcamphoformeneaminecar-
boxylic acid is very good, but is not materially affected by
doubling the quantity of amine, as, when this is done, a pre-
cipitate of «r-naphthylamine sulphate forms on acidifying and
hinders the satisfactory extraction of the acid. The crystals
deposited from benzene contain 0.5 mol. C^H^, and consist of
well-developed amber prisms. At ioo°-io5° they become
opaque, and finally change to a yellow powder, which, like
the crystals themselves, melt and decompose at 170".

Analysis :

I. 0.6574 gram substance gave 1.8634 grams CO^, and 0.3942
gram H,0.

II. 0.3796 gram substance lost 0.0393 gram at 105".

Calculated for Found.

,C : C.COOH.^CbHb
C8H,/| 1 I. II.

\CO NH.CioH,

C 77.32 77.30
H 6.70 6.66
C^H, 10.05 10.35

The acid readily dissolves in a solution of sodium carbonate.

Camphoroxalic Acid and fi-Naphthylamine.

The experiments in this case were carried out exactly as
with the a-amine, and with similar results. In all prepara-
tions made with equimolecular proportions of acid and amine
a portion of the latter was precipitated as sulphate. Potas-
sium hydrate was found to give better results than sodium
hydrate on account of its greater solubility in alcohol. It was
observed that sometimes pieces of sodium hydrate did not dis-

Afntnes and Camphor oxalic Acid. 223

solve, and produced a series of small cracks on the inner sur-
face of the glass at the point of their contact with it. This
was apparently not the case with potassium hj-drate. The
crude yS-naphthylcamphoformeneaminecarboxylic acid, ob-
tained after the removal of the ether, is purified by quickly
extracting it once or twice with hot benzene. It is then re-
crystallized from toluene and is deposited in bright-yellow
needles, melting and decomposing at 173°. The readiness
with which it forms supersaturated solutions with benzene has
been mentioned above. The yield is excellent.

Analysis :

0.2236 gram substance gave 0.6246 gram CO^, and 0.1410
gram H„0.

Calculated for
C2JH33NO3. Found.

C 75.64 76.18

H 6.59 7.00

The slight error in the carbon is doubtless due to the crys-
tals containing a trace of toluene which contains 91.30 per
cent of carbon.

Camphoroxalic Acid and Orthophenylenediatnine .

The experiments with these compounds were carried out
in the same manner as those with the naphthylamines. We
found it most convenient not to prepare the free diamine, but
to use the hydrochloride together with three molecular propor-
tions of potassium hydrate. The condensation-product does
not require to be extracted with ether. It is suflScient to dis-
solve the alcoholic residue in water, acidify, filter, wash with
a little water, and dry the precipitate on a porous plate in the
air. After two crystallizations from benzene the compound is
deposited in bright-yellow needles melting at 246°. It is
slightly soluble in hot water, is practically unchanged by
boiling with hydrochloric acid, and is only slightly acted upon
by prolonged heating with a solution of sodium hydrate. It
dissolves quickly in concentrated sulphuric acid at the ordi-
nary temperature, giving a red coloration, the change being
similar in appearance to that produced by potassium chromate
under analogous conditions. After remaining during eight

224 Tingle and Tingle.

days at the ordinary temperature a white precipitate
is obtained on dilution. This rapidly turns yellow and then
consists of unchanged crystals. The addition of a crystal of
potassium bichromate to the sulphuric acid solution does not
produce any characteristic color. If the acid solution is heated
alone decomposition gradually takes place. It readily dyes
unmordanted cotton bright-yellow. The yield is practically
quantitative. The constitution of the compound is discussed
in the first part of this paper.
Analyses :

I. 0.2550 gram substance gave 0.6785 gram CO,, and o. 1590
gram H5O.

II. 0.1216 gram substance gave 10.8 cc. N at 28°. 5 and 741
mm.

Calculated for Found.

CisHjoNjOj. I. II.

C 72.97 72.56

H 6.76 6.92 ....

N 9.46 .... 9.64

Semicarbazide and Camphoroxalic Acid.

Semicarbazide hydrochloride (4.4 grams = 2 mols.) was
mixed with the acid (4.4 grams = i mol.), potassium hydrate
(3.4 grams = 3 mols.) and alcohol (95 percent, 50 cc.) were
then added, and the solution heated at 100°, under pressure,
during four hours. After removal of the alcohol the residue
was acidified with dilute sulphuric or hydrochloric acid and ex-
tracted with ether. The acid produced a precipitate which did
not dissolve in the ether. It was removed by filtration, dried,
and frequently extracted with hot ether. The residue consti-
tuted the " /^-compound," which is insoluble in all ordinary,
neutral, organic media. It was purified by solution in boiling
glacial acetic acid. On the addition of alcohol minute micro-
scopic needles are deposited, aggregating into characteristic cu-
bical forms. After repeating this treatment several times the
product melts and decomposes at 209°-2 10°. It readily dissolves
in a solution of sodium carbonate, is reprecipitated in a
gelatinous condition as the ^-derivative on the addition of
acid, and gives no coloration with ferric chloride.

The " «r-compound" constitutes the residue obtained after
the distillation of the combined ethereal solutions mentioned

Amines and Camphoroxalic Acid. 225

above. It crystallizes from acetone in small, colorless needles,
which melt and decompose at 218°. The substance does not
evolve ammonia when boiled with a solution of sodium hy-
drate. Towards sodium carbonate and ferric chloride its be-
havior is identical with that of the /?-compound.

Analysis :

0.3053 gram substance gave 0.6129 gram CO,, and 0.1860
gram H,0.

Calculated for
/€ : C.COOH
CgHn^ I I . Found.

^CO NH.NH CO.NH2

C 55-51 54-75

H 6.76 6.76

The carbon and hydrogen content of the /^-compound is
practically identical with that of the a-derivative.

Aniline and Camphoroxalic Acid.

Camphoroxalic acid (i.i grams ■=■ i mol.), aniline hydro-
chloride (1.2 grams := 2 mols.), sodium hydrate (0.84 gram =:
3mols.), and alcohol (95 per cent, 50 cc), when heated under
pressure at 100°, during four hours, yield the phenylcampho-
formeneaminecarboxylic acid (m. p. 174°) which we have de-
scribed in our previous paper. We failed to esterify it by E.
Fischer's method, our object being to show that it is really the
acid of the ethylic phenylcamphoformeneaminecarboxylate,
prepared from ethylic caraphoroxalate and aniline, and de-
scribed below. The proof desired was, however, ultimately
obtained in the reverse manner, by hydrolyzing the ester and
isolating and identifying the acid.

We desire briefly to describe some unsuccessful attempts to
condense camphoroxalic acid :

Meta- and paraphenylenediamine hydrochlorides completely
failed to react when treated with camphoroxalic acid, sodium
hydrate, and alcohol, under pressure, at 100°, in the propor-
tions and conditions employed in the case of a-naphthylamine.
The probable reasons for this we have already mentioned.

Ethylaniliiie hydrochloride, under the same circumstances,
gave a similar result, as also did the free base and acid when
mixed and heated at 170° during two hours. No better sue-

2 26 Tingle and Tingle.

cess was attained by mixing the base and acid with benzene
and heating on the water-bath ; some solid separated from the
solution, but in quantity too small for further investigation.

Dimethylanili7ie also gave a negative result when heated
with the acid alone at i8o°, or with the acid and benzene on
the water-bath.

Ethylic Camphoroxalate and Aniline.

Ethylic camphoroxalate (2.5 grams ^ i mol.), .;iniline hy-
drochloride (2.6 grams = 2 mols.), potassium hydroxide (i
gram = less than 2 mols.), and alcohol (95 per cent, 50 cc.)
were heated together under pressure at 100° during four hours.
After removal of the alcohol the residue was treated with
water, extracted with ether, and the ethereal solution dried
and distilled. The residue, after recrystallizing from ben-
zene, is deposited in almost white, microscopic needles, which
melt and decompose at i58°-i6o°. The yield is excellent.

Analysis :

0.2682 gram substance gave 0.7172 gram CO,, and 0.1810
gram H^O.

Calculated for
/C : C.CO.OCjHg
CgH,4< I I . Found.

\C0 NH.CoHj

C 73-39 72.93

H 7.64 7.49

The compound is therefore ethylic phenylcamphoformene-
aminecarboxylate, analogous to the phenylhydrazide pre-
viously described by us, and its relationship to the corre-
sponding compound from aniline and camphoroxalic acid is
proved by its hydrolysis. When heated for about five min-
utes with warm 10 per cent aqueous-alcoholic sodium hydrox-
ide in excess, it yields the corresponding acid (m, p. 174°).
(Cf. p. 218.) Free aniline may be used for the preparation of
the compound instead of the hydrochloride and alkali, but a
large excess of the base should be avoided as it hinders crys-
tallization. We have found the above method of working
with the amine hydrochlorides and alkalies in slight deficiency
very convenient, especially when the free base is unstable or
readily volatile ; in the latter case the alkali is conveniently

Amines and Camphoroxalic Acid. 227

enclosed in a sealed tube of thin glass, which is broken after the
stopper of the pressure bottle has been securely fastened down.
We have not observed any perceptible hydrolysis of the ester
by the alkali.

Ethylic Camphoroxalate and fi-Naphthylamine.

Ethylic ^-Naphthylcamphofonneneantinecarboxylate,
,C : C.CO.OC.H,
C8H,^<^ I I , was prepared in a similar manner

\C0 NH.C,„H,
to the phenyl derivative, from ^-naphthylamine, and ethylic
camphoroxalate in alcoholic solution. Any unchanged amine
is removed by means of benzene, and the residue then re-
crystallized from the same solvent. It is deposited in color-
less, microscopic needles, which soften at about 160°, and
melt and decompose at 174°, but the melting-point varies ac-
cording to the rapidity with which the bath is heated. The
compound is not affected by boiling water nor by boiling aque-
ous sodium carbonate except for the production of a superfi-
cial yellow color.

Analysis :

0.3392 gram substance gave 0.9446 gram CO,, and 0.2242
gram H,0.

Calculated for
C,4H,,N03. Found.

C 76.39 75-94

H 7.16 7.34

No definite compound could be isolated except apparently
unchanged naphthylamine, by heating ethylic camphoroxa-
late with ^-naphthylamine at i40°-i45° during three hours.

Ethylic Camphoroxalate and Semicarbazide.

Ethylic Semicarba2ylcam.phoformenecarboxylate,
yC : C.CO.OC.H,
C8Hj^<(' II , is prepared by heating the

\C0 NH.NH.CO.NH,
ester with semicarbazide hydrochloride (3 mols.j, potassium
acetate (3.5 mols.), and alcohol (95 per cent), at 100°, under
pressure, during four hours, or by allowing the substances to
remain at the ordinary temperature in dilute alcoholic solution

228 Tingle and Tingle.

during seven days. In the former case the compound was
extracted by means of ether ; in the latter it separated on
dilution with water. It is readily soluble in ethylic acetate,
chloroform, and ether, moderately so in benzene and acetone,
and sparingly in ligroin. It is deposited from ethylic acetate
in colorless needles, melting at 202°. The yield is good
whichever method of preparation is employed. In one ex-
periment, carried out at 100°, a compound was obtained in
small quantity, which did not dissolve in either the ethereal
or aqueous layers of liquid, nor in any organic solvent we
could employ. It crystallized in needles, melted at 255°, and
may be semicarbazide sulphate, as the aqueous solution had
been acidified with dilute sulphuric acid. Neither J. Thiele
and O. Strange,' who first prepared this salt, nor F. Tiemann
and P. Kriiger/ who subsequently employed it, give the
melting-points of their preparations.
Analyses :

I. 0.4832 gram substance gave 1.0056 grams CO,, and 0.3360
gram H,0.

II. 0.4532 gram substance gave 0.9438 gram CO,, and
0.3234 gram H,0.

III. 0.1540 gram substance gave 19.4 cc. N, at 27° and
746.6 mm.

13.64

Calculated for

Found.

C,,H,3N304.

I.

II.

(Mol. wt. = 309.)

c

58-25

56.75

56.79

H

7-44

7.72

7.92

N

13-59

....

....

Molecular weight determinations
Solvent, phenol.

Weight of
solvent.

Weight of
substance.

A.

m.

Grams.

Gram.

19.6330

O.I 145

0.19°

227

19.6330

0.2220

0.36°

232.5

Ethylic Camphoroxalate and Orthophenylenediamine.
The ester reacts with the orthodiamine hydrochloride and

1 Bar. d. chem. Ges., 27, 34.

2 Ibid., 28, 1754-

Amines and Camphoroxalic Acid. 229

sodium hj-drate, in presence of alcohol, at 100°, under pres-
sure. The product was isolated by evaporating off the alco-
hol and washing with water. Its appearance and melt-
ing-point proved it to be identical with the corresponding
compound from sodium camphoroxalate. In the first experi-
ments two molecular proportions of amine hydrochloride, to-
gether with the equivalent amount of sodium hydrate, were
employed; subsequently, in order to avoid any chance of hydrol-
ysis, exactly equimolecular proportions of the ester and amine
were taken, with a small deficiency of sodium hydrate, but
without appreciably affecting the result. The yield is large.

Unsuccessful Experiments with Ethylic Camphoroxalate .

Meta- and paraphenylenediamine yielded only tarry matter
when treated with ethylic camphoroxalate under the
same conditions as the ortho-compound, A similar result
was obtained in the case of «-naphthylamine, both at 100°
under pressure, and at i40°-i45°. In both experiments the
only products which could be isolated were the original ma-
terials. Ethylaniline, both as free base and as hydrochloride,
together with sodium hydrate, and dimethylaniline in the free
state, at 100°, under pressure, in alcoholic solution, also failed
to give an)' condensation-products.

Experiments with Phenylcamphoformeneamine.

Benzoyl chloride reacts with phenylcamphoformeneamine,
in presence of a little sodium hydrate, either when gently
warmed or at the ordinary temperature if allowed to remain
during thirty-six hours. The latter appears to be the prefer-
able method. The product was well washed with a solution
of sodium carbonate, extracted with ether, the ether dried
and removed, and the residue recrystallized from benzene.
The compound is deposited in cruciform aggregates of prisms
resembling potassium nitrate in appearance, and melting at
160^-161°. It has not yet been further investigated. An at-
tempt to prepare it by the ordinar)'- Schotten-Baumann method,
in aqueous solution, was not successful, as benzoic acid was
the only product that could be isolated in quantity.

Phenylsulphonic chloride does react with the amine by the

230 Ktihara and Chikashigi.

Schotten-Baumann method, but when the two are simply
heated together they only yield an oil. The product has as
yet only been obtained in small amount. It is readily deposi-
ted from benzene in colorless needles, melts at 133°, and does
not dissolve in a solution of sodium hydrate.

The amine, when boiled with 10 molecular proportions of
acetic anhydride during fifteen minutes, yields a brown
liquid, which deposits a gummy substance after treatment
with a solution of sodium carbonate. Recrystallization from
a mixture of ethylic acetate and ligroin yields colorless crys-
tals, which, after draining on a porous plate, melted at 134°.
The crystals were always accompanied by resinous matter,
and, as repeated recrystallizations failed to effect any separa-
tion of the two, further attempts to purify the compound were
abandoned. We propose to continue this work in various
directions.

Lewis Institute, Chicago, III. University of Wisconsin,

Madison, Wis.

A METHOD FOR THE DETERMINATION OF THE
MELTING-POINT.

By M. Kuhara and M. Chikashige.

Several different methods have hitherto been suggested for
determining the melting-point of substances. One of these,
that now in common use, consists in heating the substance to
be experimented upon in a capillary tube, fastened to a ther-
mometer, and immersed in a bath. It is usual, in this case,
to take the temperature at which the substance begins to
melt away from the walls of the capillary tube as its melting-
point. This method, however, is very liable to give too high
results, as it is difficult to observe the exact point of fusion of
that portion of the substance which is in contact with the
walls of the tube, before the inner portion thereof reaches its
melting-point ; this is apparently higher than the real melt-
ing-point, owing to the bad conductivity of the air contained
in the interstices of the substance, and the consequent over-
heating. We also find another disadvantage in this method ;
namely, that substances which cannot be pulverized, such as

DetermmatioJi of the Melting-point.

231

waxes, fats, etc., are, with difl5culty, introduced into the capil-
lary tube.

We have recently devised a method which, we think, will
eliminate all the disadvantages of the tube method, and
which, moreover, can easily be carried out in chemical labora-
tories.

In this new method, instead of a capillary tube, we make
use of a pair of cover-glasses for microscopical purposes, cut
in halves, between which the substance to be tested is intro-
duced, either in powder, in crystals, or in thin slices. If the
substance is in the state of powder, we can make the layer as

10

thin as possible by pressing and sliding the two pieces with the
fingers, so that the heat of the bath may at once be conducted
throughout the whole mass. The surface exposed is very
large compared with the quantity of the substance taken, and,
consequently, its behavior towards heat can be distinctly ob-
served. Before the substance is melted the glass appears
opaque, while it becomes transparent when fusion occurs.
The thinner the layer the more distinct is the difference ; but
with volatile substances, a quantity somewhat in excess of
what is apparently essential should be taken, in order to make
allowance for loss by volatilization.

The pair of glass-pieces is then fastened to a holder made

232 Kuhara and ChikashigS.

of platinum foil and tied, if necessar}', with a piece of fine
wire of the same material. The holder, which can easily be
made by folding the foil and cutting it with scissors, as shown
in the annexed figure, is suspended in a wide test-tube, into
which is inserted a thermometer close to the holder. The
test-tube, serving as an air-bath, is immersed in the sulphuric-
acid bath almost to its mouth. The further steps of the pro-
cess require no modification of the old methods.

The glass pieces can be used any number of times, unless
they are broken ; this is considered another advantage over
the tube method.

The result of experiments with our method is given in the
following table. The substances taken were purified by re-
peated crystallization, and the temperatures given are the cor-
rected ones :

M. p.
already
Substance. Exp. I. Exp. II. Exp. III. Mean, known. Observer.

Chloral hydrate 57^.3 57^.3 57^.0 57^.2 57° | anYoulk

Urea 132". i 132°. i i32°.3 132°. 2 132° L,ubavin

Phthalic acid 203°. 2 202''. 7 203°. o 203°. o 203° Ador
Phthalimide 233''. 6 233°, 7 233°. 6 233°. 6 233°. 5 Graebe

The melting-point of phthalic acid has been a subject of
discussion, the figures given by different observers differing
considerably. Lossen' gives it as low as 184°, but Ador^
states that cr3'stallized phthalic acid melts at 213° and the
powdered substance at 203°. Remsen^ ascribes the variation to
the fact that phthalic anhydride, formed partly from the acid,
lowers the melting-point of the mixture. In order to test his
view, small quantities of the acid, introduced into a [j-tube,
were heated over a paraffin- bath at the temperatures of 140°
and 170°, and the melting-point was found to be considerably
lower in both cases. This experiment was conducted by one
of us a number of years ago, when working in his laboratory.
We have found, however, with the new method, that both the
crystallized and the powdered substances melt at the same
constant temperature of 203'', whether the air-tube is grad-

1 Ann. Chera. (Liebig), 144, 76.

^ Ibid., 163, 230.

3 This Journal, 8, 30.

\

Chloride of Paranitroorthosulphobensoic Acid. 233

ually heated or plunged at once into the bath at a tempera-
ture above 205°. This is probably due to the fact that the
anhydride formed is freely volatilized in our apparatus through
the interstices of the two glass-pieces, and the remaining acid,
kept pure, melts at its proper temperature. With our method
we have never observed a temperature so high as 213°, nor so
low as 184°, while with the capillary-tube method we often
noted a melting-point as low as 185°.

Chemical Laboratory,

The Imperial University,

Ky6to, Japan.

THK SYMMETRICAL CHLORIDE OF PARANITRO-
ORTHOSULPHOBENZOIC ACID.'

By F. S. Hollis.

Introductio7i .

The present investigation may be divided into two parts.
The first consists of further work on the method of prepara-
tion and separation of the chlorides of paranitroorthosulpho-
benzoic acid. This work was confined largely to the unsym-
metrical or low-melting chloride, as this is the one used
mainly in the second part of the investigation. The prepara-
tion of the unsj^mmetrical dichloride, first obtained by Rem-
sen and Gray,* was found to be a matter of considerable difii-
culty and uncertainty, unless the crystallization could be con-
ducted out of doors at a very low temperature.

As the result of a series of experiments, undertaken to de-
termine the best conditions for the preparation of the unsym-
■ metrical chloride, a method has been devised by which the
unsymmetrical chloride can be prepared in any desired quan-
tity in the laboratory.

The second part of the investigation consists of a study of
the action of benzene and aluminium chloride on the chlorides
under varying conditions, and the preparation of a series of
derivatives of the product formed.

1 From the author's dissertation submitted to the Board of University Studies of
the Johns Hopkins University, June, 1896, for the degree of Doctor of Philosophy.
The investigation was undertaken at the suggestion of Professor Remsen and was
carried on under his guidance.

2 This Journal, 19, 496.

234 Hollis.

Remsen and Saunders' and Remsen and McKee,* working
with the chlorides of orthosulphobenzoic acid, found that the
action of benzene and aluminium chloride gives the same
products with both chlorides.

It was thought that, on account of the greater stability of
the paranitroorthosulphobenzoic acid, the action of benzene
and aluminium chloride might lead to the formation of two
series of derivatives, one derived from the symmetrical chlo-
ride and the other from the unsymmetrical chloride, in which
the resulting compound would retain the unsymmetrical struc-
ture of the chloride. This proved not to be the case, as the
product of the action of benzene and aluminium chloride on
both of the chlorides was found to be paranitroorthobenzoyl-
benzenesulphone chloride.

It was found that paranitroorthosulphobenzoic acid does
not yield a sulphone corresponding to the one obtained from
orthosulphobenzoic acid by Remsen and Saunders,' although
the reaction was conducted under the conditions used by them,
as well as under a variety of different conditions.

Preparation of Material.

The acid potassium salt of paranitroorthosulphobenzoic acid
was prepared from paranitrotoluene according to the method
described by Kastle," and used later by Remsen and Gray.*

One thousand grams of paranitrotoluene gave 1439 grams
of the neutral potassium salt of paranitrotolueneorthosulphonic
acid. One thousand grams of the potassium salt of para-
nitrotolueneorthosulphonic acid gave 800 grams of the acid
potassium salt of paranitroorthosulphobenzoic acid.

The Action of Phosphorus Pentachloride on the Acid Potassium
Salt of Paranitroorthosulphobenzoic Acid.

The action of phosphorus pentachloride on the anhydrous
acid potassium salt of paranitroorthosulphobenzoic acid gives
rise to the formation of an unsymmetrical and a symmetrical
dichloride, as determined by Remsen and Gray,* according to
the following equations :

1 This Journal, 17, 355. 2 Ibid., 18, 794.

^ Loc. cit. * This Journal. 11, 177.

5 Loc. cit. * Loc. cit.

Chloride of Paranitroorthosulphobenzoic Add. 235

CeH, -^ SO,OK + 2PCI, = C.H3 \ SO, ^^ + 2POCI3 + HCl
(NO, (no,

+ KCl.

(COOH rcoci

CeH, \ SO,OK H- 2PCI, = C.H, \ SOXl + 2POCI, + HCl +
(NO, (no,

KCl.

Remsen and Gray' found that the relative amount of each
chloride depends on the temperature and length of time which
the phosphorus pentachloride is allowed to act on the acid
potassium salt. The largest amount of the unsymmetrical
chloride, amounting to 80 or 90 per cent of the total, was
formed by heating a mixture of 2 molecules of phosphorus
pentachloride and i molecule of the anhydrous acid potassium
salt to 150° C. for four or five hours in a distilling-bulb, im-
mersed in a sulphuric-acid bath.

Under these conditions, the amount of symmetrical chloride
formed amounted to 10 or 20 per cent of the total, but this is
increased to 30 per cent by heating in an open dish on a
water-bath. The symmetrical chloride was separated by
using chloroform as a solvent.

As considerable difiiculty was experienced, mainly in the
preparation of the unsymmetrical chloride, according to the
directions given by Remsen and Gray, a series of experiments
was made under different conditions with amounts of the acid
potassium salt varying from 20 to 60 grams in order to deter-
mine the conditions most favorable for the formation of the
unsymmetrical chloride. The results of these experiments
are embodied in the following method.

a. The Preparation of the Unsymmetrical Chloride. — A mix-
ture of I molecule of the acid potassium salt, previously
heated to 150° C. for four hours, and 2.5 molecules of phos-
phorus pentachloride is carefully ground together in a mortar
and introduced into a distilling-bulb having a capacity of
about six times that of the volume of the mixture. The
outlet tube of the bulb is closed, and a cork, through which
runs a glass tube about 3 feet long, the lower end reaching
nearly to the surface of the mixture, inserted in the neck.

1 Loc. cit.

236 Hollis.

The distilling-bulb, thus closed, is immersed in a sulphuric-
acid bath, previously heated to 150° C, and this temperature
maintained for five hours.

No reaction takes place on mixing the acid potassium salt
and the phosphorus pentachloride, but upon immersing the
bulb containing the mixture in the heated bath, vigorous ac-
tion begins immediately, and the resulting phosphorus oxy-
chloride is conducted back upon the product by means of the
condensing-tube. The temperature of 150° C. cannot safely
be exceeded, as decomposition of the chloride begins at
160° C.

At the end of five hours the tube is removed from the neck
of the flask, the perforated stopper replaced by a solid one,
the outlet tube opened, and the phosphorus oxychloride dis-
tilled off.

The resulting chloride, which is in the form of a thick,
yellow, oily liquid, is poured into a large bottle, nearly filled
with cold water, and shaken vigorously so as to break it into
small globules. This washing is continued until the chloride
hardens to a solid cake, which commonly takes place after
washing with five or six successive portions of cold water.
The solidified chloride is broken up and dried by pressing be-
tween filter-paper, and in this form it may be exposed to the
air without undergoing much, if any, decomposition.

By using 2.5 moleculesofphosphoruspentachloride, all of the
acid potassium salt is converted into the form of the chloride,
while, if but 2 molecules are used, varying amounts of the
acid potassium salt, in some cases as much as 25 per cent, are
unacted upon and may be recovered from the wash-water.

The product obtained by this method consists, with the ex-
ception of slight impurities, of only the unsymmetrical chlo-
ride, thus making the crystallization from chloroform unnec-
essary. One hundred grams of anhydrous acid potassium
salt gave, on an average, 99 grams of the crude unsymmet-
rical chloride.

Previous work showed that the crystallization of the un-
symmetrical chloride from ligroin (50°-8o°) was a diSicult
matter, unless it could be done out of doors during very cold
weather. The same was found to be the case with the un-

Chloride of Paranitroorthosulphobenzoic Acid. 237

symmetrical chloride of orthosulphobenzoic acid by Remsen
and Saunders.'

A solution of the crude chloride in purified ligroin (50°-
80°), on standing out of doors at a temperature of 6° F., crys-
tallized in clusters of crystals, some of which measured 3 cen-
timeters in length. An attempt was made to obtain the chlo-
ride in the form of crystals by cooling the ligroin solution to
0° C. in a refrigerating box, such as was used by Remsen and
McKee.* The chloride invariably separated as an oil, and no
advantage was derived by drawing a current of cold, dry air
through the flask containing the ligroin solution. Some of
the oily chloride which separated from the ligroin solution,
and from which the ligroin had been decanted, formed an
opaque semisolid mass on placing it in a freezing-mixture,
but no crj^stals were deposited.

The first indication of crystallization in the laboratory was
obtained on placing some of the oil, which had been dissolved
several times in fresh portions of hot ligroin (so^-So") and
allowed to separate out on cooling, in a freezing-mixture, and
stirring with a rod. This suggested the possibility that some
material, which by its presence retards crystallization, had
been dissolved out of the mass by the several portions of
ligroin in which it had been dissolved. This was shown to
be the case by several tests, and gave rise to the following
method of purification and cr^-stallization, in which the
further change is made of using ligroin of boiling-point 90°-
125° as the solvent. This ligroin is to be preferred to that
having a lower boiling-point, as the chloride is apparently
much more soluble in it, and crystallizes from the solution at
the temperature of the laboratory. The ligroin is purified by
shaking in a separating-funnel with concentrated sulphuric
acid until it imparts no color to a fresh portion of acid, after
which it is treated with a solution of caustic soda to neutralize
the acid, and washed free from alkali hy water.

The crude chloride, which is always somewhat dark col-
ored and gummy, is placed in an Erlenmeyer flask with puri-
fied ligroin (5o°-8o°) and washed by stirring it with a rod un-
til it yields a granular powder having but little color.

1 Loc.cit. 2 Loc. cit.

238 Mollis.

On boiling the chloride thus purified with ligroin (90°-
125°), it dissolves, with the exception of slight remaining im-
purities, and on cooling the solution becomes cloudy, and the
excess of chloride separates out as a light-colored oil. It is
best to decant the solution from the separated oil after sepa-
ration has mainly ceased at the temperature at which crystal-
lization is to proceed, but before the solution has become
clear. The chloride is obtained from this solution at the
temperature of the laboratory in clusters of needles having
the form of long monoclinic prisms as observed by Remsen
and Gray.' The rate of cry.stallization is increased by keep-
ing the solution at a lower temperature, but no especial ad-
vantage is derived unless the temperature is very low, when
larger crystals are obtained. The crystals of the chloride
thus obtained have a constant melting-point of 57° C. (uncorr. ) .

The purified chloride which separates from the ligroin as
an oil generally crystallizes on standing, but it is better to
redissolve it in a fresh portion of ligroin, by which it is
further purified, and proceed according to the directions given
above.

The principal impurity which causes difficulty in the crys-
tallization of the unsymmetrical chloride seems to be that
which is removed by the preliminary treatment with ligroin
(50°-8o°).

On evaporating the ligroin used in washing the chloride,
this impurity remains as a dark-colored, slightly viscous
liquid having a strong acid reaction. It showed no tendency
to crystallize after standing in the laboratory for five months.
A small amount of another impurity was obtained as a floc-
culent material on dissolving the crude chloride in chloro-
form. It melts after purification at ioo°-io5° C, and is prob-
ably the anhydride.

b. The Preparation of the Symmetrical Chloride. — One por-
tion of the symmetrical chloride was made in order to test the
action of benzene and aluminium chloride, but no compara-
tive tests were made, as in the case of the unsymmetrical
chloride. The method used for its preparation differed some-
what from that of Remsen and Gray.

1 Loc. cit.

Chloride of Paranitroorthosulphobenzoic Acid. 239

The conditions chosen for its preparation were, as far as
possible, the opposite of those found to be most favorable for
the formation of the unsymmetrical chloride.

The anhydrous acid potassium salt and phosphorus penta-
chloride, in the proportion of i molecule of the former to 2
molecules of the latter, are mixed b}^ grinding them together,
and the action commenced by placing the vessel containing
the mixture in a sulphuric-acid bath previously heated to
150° C.

The vessel is removed from the bath as soon as the action
commences, and allowed' to stand until the action is complete,
which requires about ten minutes.

The mass is washed, as in the case of the unsymmetrical
chloride, by shaking in a bottle with five or six portions of
cold water.

The chloride thus washed exists in the form of a light-
colored, thick gum. It is dissolved in anhydrous chloroform,
the solution dried by means of calcium chloride, and allowed
to stand at the temperature of the laboratory. Crystals of the
symmetrical chloride are formed only after the chloroform has
nearly all evaporated, and crystallization proceeds very
slowly.

The chloride was obtained in the form of small monoclinic
crystals, having a constant melting-point of 94° C. (uncorr.).

The yield indicated that, under the conditions used, the
action of the phosphorus pentachloride is complete, but be-
tween 35 and 40 per cent of the product obtained consists of
the symmetrical chloride.

The Action of Benzene and Aluminium Chloride on the Chlorides
of Paranitroorthosulphobenzoic Acid.

a. The Action on the Unsymmetrical Chloride. — When alumin-
ium chloride is added to a solution of the unsymmetrical
chloride in benzene, slight action begins immediately, as is
shown by the darkening of the color of the solution and a
slight evolution of hydrochloric acid gas.

In the case of small quantities of the chloride, heated with
an excess of aluminium chloride, the reaction is complete in
from fifteen to twenty minutes. A series of experiments was

240 Hollis.

made in order to determine the best conditions for conducting
the reaction and for separating and purifying the product.

Under some conditions the product contains a considerable
amount of a dark-purple material which separates as an im-
purity on crystallization. As a result of these experiments,
the following method was adopted :

Twenty grams of the unsymmetrical chloride is dissolved in
100 cc. of benzene in a flask provided with a return-conden-
ser, and about 10 grams of aluminium chloride in small pieces
added. This is heated with a small flame for from one to two
minutes, at the end of which time vigorous action commences
and continues without further heating for ten minutes.

After the action is over the flask is heated repeatedly so as
to maintain an even evolution of hydrochloric acid gas for
about eight minutes, at the end of which the reaction is com-
plete. The resulting product is poured into 750 cc. of water
in a liter separating-funnel, 75 cc. of hydrochloric acid (sp.
gr. 1. 12) added and the mixture well shaken.

After the benzene layer has risen the water is drawn off and
the small amount of the product suspended in it separated by
filtration. The greater part of the product is in the form of a
pinkish-white powder, which remains in suspension in the
benzene, from which it is separated by filtration, dried, and
purified with the portion obtained from the water. The prod-
uct is purified by dissolving in benzene and adding rather
more than an equal volume of anhydrous ether, which causes
a more rapid crystallization. By this method it is obtained in
clusters of small, apparently monoclinic crystals, having a
rhombohedral habit, or as a granular powder if crystallization
takes place rapidly.

Some of the larger crystals measured 4 or 5 mm. on an edge.
The larger crystals have a purple or green color, and the
granular form is generally slightly green. Both forms yield a
white powder. The pure crystalline product has a constant
melting-point of 177° C. (uncorr.).

The portion of the product which remains in solution in the
benzene is mixed with a small amount of the purple impurity
before described, but it is obtained in a crystalline form of
fair purity by drying the benzene solution, evaporating it

Chloride of Parayiitroorthosulphobenzoic Acid.

241

to about one-third of its volume, and adding rather more than
an equal volume of absolute ether. The dark impurity may
be largely removed by washing with absolute alcohol, in which
it dissolves readily.

An attempt was made to prevent the darkening of the ben-
zene solution during evaporation by conducting the evapora-
tion in a current of sulphur dioxide, as it was believed that
the darkening was due, in part at least, to the action of the
air.

The product was not materially improved, and a certain
amount of free acid was always found to be present after such
treatment. The rapid evaporation of the dried benzene solu-
tion and the addition of an equal volume of absolute ether to
insure rapid crystallization is greatly to be preferred.

Twenty grams of the unsymmetrical chloride gave 16 grams
of the product as first obtained. This was slightly decreased
bj' recrystallization.

The product has a characteristic disagreeable odor.

b. The Action on the Symmetrical Chloride. — The reaction
was conducted exactly as in the case of the unsymmetrical
chloride, the same relative quantities and method of treatment
being used. The method of separation was also the same.

The product gave, on purification, crystals of the same
form, size and color as those obtained from the unsymmetrical
chloride.

The melting-point of the purest crystals is also the same,
177° C. (uncorr. ).

Two grams of the symmetrical chloride gave 1.5 grams of
the product.

Analyses of the product of the action of benzene and alu-
minium chloride on the unsymmetrical chloride :

0.2051

gram gave

0.3632 gram CO,

0.2992

c

0.5249 "

0.1994

(

0.0535 " H,0

0.2992

t

0.0819 "

0.2508

(

9.03 cc. N

0.3496

(

12.88

0.2601

(

0.1957 gram BaSO,

0.2058

1

0.1584 "

0.2602

'

0.1888 "

242

Mollis .

0.2492 gram gave 0.1878 gram BaSO,

0.2424 " " 0.1811 " "

0.2434 " " 0.1072 " AgCl

0.2058 " " 0.0925 "

0.2602 " " 0.1161 " "

Calculated for

Found.

CijHsOjNSCl.

I.

II.

III. I

c

47.92

48.29

47.84

H

2.45

2.97

3-04

N

4-30

4-32

4.42

S

9-83

10.33

10.56

9.96 10.

CI

10.90

10.90

II. II

11.03

34 10.26

The two following structural formulae are possible for a
substance derived from the unsymmetrical chloride, and hav-
ing the composition indicated by the analyses.

C,H,NO,<^

C— CI

\

so/

C6H3.NO

<

COC.H,

S0,C1

The fact that the product is apparently not acted upon by
alcoholic potash, together with its high melting-point and its
properties generally favor the belief that it has the structure
represented by the first.

The formation of the same product by the action of benzene
and aluminium chloride on the symmetrical chloride seems to
indicate that the product derived from each chloride is para-
nitroorthobenzoylbenzenesulphone chloride. This view agrees
with the results obtained by the action of benzene and alumin-
ium chloride on orthosulphobenzoic acid by Remsen and
Saunders' and Remsen and McKee.''

It is clear from the analysis that but one of the chlorine
atoms of the chloride is replaced by this reaction. All at-
tempts to prepare the diphenyl derivative or paranitroortho-
benzoylbenzenesulphone were unsuccessful, although the con-
ditions were varied widely, both as to temperature and the
length of time which the heating was continued.

The conditions already described give the best yield and
also the purest product.

1 Loc. cit.

2 Lor. cit.

Chloride of Paraniiroorthosulphobenzoic Acid. 243

By allowing the mixture to stand for a day with occasional
heating nearly to the boiling-point of the benzene, similar
good results are obtained.

By heating to the boiling-point of benzene, for three hours,
using a return-condenser, the yield is decreased, and a large
amount of a black, tarry matter obtained, which is almost
insoluble in benzene. This dissolves readily in absolute
alcohol, from which solution it is precipitated as a dark red-
colored powder on adding water, and after being thrown out
of solution in this way, it becomes less soluble in absolute
alcohol.

It swells up on heating and gives an odor like that obtained
on burning sulphonic acids. On burning off the organic por-
tion a considerable amount of alumina remains. Hydrochloric
acid dissolves the alumina, leaving the organic portion in the
form of a black, tarry mass.

The Action of Hydrochloric Acid on Paranitroorthobenzoylben-
zenesulphone Chloride.

a. The Action of Dihtte Hydrochloric Acid (sp.gr. 1.12). —
The action of dilute hydrochloric acid was determined by
boiling the sulphone chloride in a flask, provided with a re-
turn-condenser, with an excess of the acid until it was all dis-
solved, which usually requires about six hours. The solu-
tion is then filtered and evaporated on a water-bath, and the
heating continued until no odor of hydrochloric acid remains.
The resulting acid is obtained in the form of a dark, solid
substance, which dissolves readily in water and takes up
water on standing in the air.

• Barium Salt. — The barium salt was prepared by adding
barium carbonate to a solution of the acid in water, filtering
off the excess of barium carbonate, and evaporating the solu-
tion under a bell-jar by means of a current of dry air. The
solution cannot be concentrated safely by boiling, as it causes
a decomposition of the salt.

The salt was obtained in the form of small, light-colored
crystals, arranged in tufts.

In the following analyses of salts, the base, as well as the
sulphur, is calculated on the basis of the anhydrous salt.

244 Hollis.

I. 0.2039 gram substance lost 0.0119 gram at 180° C, and
gave 0.0586 gram BaSO^.

II. 0.2892 gram substance lost 0.0179 gram at 180" C, and
gave 0.0810 gram BaSO^.

Calculated for

Fou

nd.

(C,3Hg06NS)jBa+3H20.

I.

II.

H„0 6.72

5.84

6.18

Ba 18.29

18.12

17-65

The barium salt of another portion of acid, prepared in the
same way, was obtained in the form of short, thick, mono-
clinic prisms, which seemed to be made up of a series of
plates. ■>

I. 0.2010 gram substance lost 0.0260 gram at 210° C, and
gave 0.0557 gJ'am BaSO^.

II. 0.2021 gram substance lost 0.0250 gram at 210° C, and
gave 0.0562 gram BaSO^.

III. 0.2263 gram substance gave 0.1262 gram BaSO^.

IV. 0.2109 gram substance gave 0.1201 gram BaSO^.

Calculated for

Found.

(C,sH80eNS)3Ba + 6H5O.

I.

II.

HP 12.60

12.93

12.66

Ba 18.29

18.64

18.70

S 8.54

8.76

8.93

This salt became opaque on standing in a specimen tube
for one month, due to the loss of water of crystallization.
0.2133 gram of the opaque salt lost 0.0139 gram at 210° C.

Calculated for
(C,3H60eNS)jBa + 3H.i0. Found.

H,0 6.72 6.56

The results of the analysis indicate that paranitroorthoben-
zoylbenzenesulphone chloride is converted into paranitroortho-
benzoylbenzenesulphonic acid by boiling with dilute hydro-
chloric acid, according to the following equation :

/COC.H, /COC\H,

C,H3N0,< = C,H,NO/

\S0,C1 + H,0 \SO,OH + HCl

b. The Action of Concentrated Hydrochloric Acid (sp. gr.
1. 1 7). — The action of concentrated hydrochloric acid was de-
termined by heating the sulphone chloride with a large excess
of acid in a sealed tube.

Chloride of Paranitroorthosulphobenzoic Acid. 245

The tube was first heated for six hours in a water-bath,
but, as no action seemed to take place, it was transferred to a
Carius furnace and heated for six hours at a temperature of
175° C. The substance dissolved, with the exception of a
few dark flakes, and the acid was colored brown. The flakes
were removed b}^ filtration, the acid solution evaporated to
dr3mess on a w^ater-bath, and the heating continued until the
resulting acid had no odor of hj-drochloric acid. The barium
salt was prepared as in the case of the acid derived from the
sulphone chloride by the action of dilute hydrochloric acid.
It crystallized in the form of light-colored, fine needles, which
were arranged in loose tufts or clusters. A few darker crys-
tals in the form of larger monoclinic crystals with rhombohe-
dral habit were obtained from the mother-liquor.

I. 0.2103 gram of the needles lost 0.0164 gram at 210° C,
and gave 0.0609 gram BaSO^.

II. 0.2083 gram of the needles lost 0.0158 gram at 210'' C,
and gave 0.0595 gram BaSO,.

Calculated for
(Ci3H806N3)2Ba-f 3^HjO.

I.

Found.

II.

H,0 7-75
Ba 18.29

7.69
18.21

7-59
18.20

0.1053 gram of the larger, dark crystals lost 0.0152 gram at
210° C, and gave 0.0279 gram BaSO^.

Calculated for
(Ci3H806NS)5Ba + yHjO. Found.

H,0 14.40 14.43

Ba 18.29 18.20

The Action of Dilute Sulphuric Acid on Paranitroorthobenzoyl-
benzenesulpho7ie Chloride.

The action of sulphuric acid on the sulphone chloride was
determined by heating in a flask with a return-condenser un-
til it dissolved. The resulting product was an acid, which
was converted into the barium salt by adding an excess of
barium carbonate, as in the previous experiments.

The barium salt was obtained in the form of short needles
arranged in clusters.

0.1943 gram substance lost 0.0119 gram at 180° C, and gave
0.0570 gram BaSO,.

246 Mollis.

Calculated for

(C,3H80eNS)5Ba + 3H50.

Found.

H,0

6.72

6.12

Ba

18.29

18.48

The Action of Water on Paranitroorthobenzoylbenzenesulphone

Chloride.

The action was determined by boiling the sulphone chloride
in a flask with a return-condenser until it dissolved. It was
necessar}' to boil somewhat longer to dissolve the substance
than in the experiments in which acids were used.

The resulting product was an acid which, by treating in the
usual way with barium carbonate, gave a barium salt which
crystallized in well-formed monoclinic crystals.

0.1610 gram substance lost 0.0207 gram at 210° C, and
gave 0.0443 gram BaSO^.

Calculated for
(CiaH806NS)2Ba + 6H2O. Found.

H,0 12.60 12.85

Ba 18.29 18.56

The Action of Absolute Alcohol on Paranitroorthobenzoylbenzefie •
sulphone Chloride.

The action of absolute alcohol on the sulphone chloride was
determined by boiling in a flask with a return-condenser un-
til it dissolved. It dissolved rather more rapidly than in the
experiments in which acid was used, and the boiling was con-
tinued for a short time after all the material was dissolved.
After a part of the alcohol was evaporated, a few drops of the
solution showed indications of crystallization on evaporating
rapidly on a watch-glass, but, on further evaporation, the
solution darkened and the resulting product was an acid as in
the previous experiments.

The barium salt was prepared as in the previous experi-
ments. The crystals first obtained were in the form of small,
light- colored needles arranged in clusters, but later well-
formed monoclinic crystals were obtained from the same solu-
tion.

0.1957 gram of the needle-shaped crj^stals lost 0.0153 gram
at 210° C. , and gave 0.0559 gram BaSO^.

Chloride of Paranitroorthosulphobenzoic Acid. 247

Calculated for

(C,3H80gNS),Ba +3JH5O. Found.

H,0 7-75 7-8i

Ba 18.29 18.21

0.2007 gram of the larger crystals lost 0.0285 gra^i at 210°
C, and gave 0.0535 gram BaSO,.

Calculated for

(Ci3H806NS)2Ba + yHaO.

Found.

H„0

14.40

14.26

Ba

18.29

' 18.27

The above analyses indicate that the action of dilute or con-
centrated hydrochloric acid, sulphuric acid, water and alco-
hol on paranitroorthobenzoylbenzenesulphone chloride con-
verts it into paranitroorthobenzoylbenzenesulphonic acid.

Comparisoii of the Barium Salts.

The analyses of the barium salt of the acids, derived from
the action of the various substances on the sulphone chloride,
show that the acid is in every case the same and that the salts
contain the same amount of barium when calculated upon the
basis of the anhydrous salt. The amount of water of crystal-
lization varies widely in the different salts, depending on the
conditions under which crystallization takes place.

The needles are obtained from the more concentrated solu-
tions, and crystals of this form are first obtained from a solu-
tion which has been evaporated by heating before placing it
under a bell-jar. All crystals having this form contain 3 or
3.5 molecules of water of crystallization.

The larger monoclinic crystals which form in the same solu-
tion after the formation of needles ceases, or when a cold solu-
tion is evaporated to the point of crystallization under a bell-
jar, contain 6 molecules of water of crystallization. On ex-
posure to the air or even in a stoppered tube these lose water
of crystallization and become opaque.

The only analysis made of a crystal that had changed in
this way shows that it contains 3 molecules, while it crj'stal-
lized with 6.

Those crystals which contain 7 molecules of water of crys-
tallization are obtained on slow crystallization, on standing in
the air, from a dilute solution or from a mother-liquor from

248 Hollis.

which cr3^stals containing a less amount of water of crystal-
lization have been deposited.

Although all the barium salts containing different amounts
of water of crystallization appear to crystallize in the mono-
clinic system, they show clearly a variation in form.

Owing to lack of time, no comparative study could be made
of the relation existing between the amount of water of crys-
tallization and the crystallographic constants.

The barium salt of paranitroorthobenzoylbenzenesulphonic
acid is characterized by an intense bitter taste.

Preparation of Other Salts from the Barium Salt of Paranitro-
orthoben zoylbenzenestdphonic Acid.

These were prepared from an aqueous solution of the barium
salt by precipitating the barium exactly by means of sulphuric
acid and neutralizing the free acid exactly with the carbonate
of the base.

The solutions were evaporated to crystallization under a
bell-jar by means of a current of dry air.

In the analyses the amount of the base is calculated on the
basis of the anhydrous salt.

a. The Sodium Salt. — The sodium salt was obtained in the
form of fine white crystals composed apparently of monoclinic
prisms.

They appear to undergo no change on exposure to the air.

I. 0.1898 gram substance lost 0.0105 gram at 210° C, and
gave 0.0384 gram Na^SO^.

II. 0.2022 gram substance lost o.oiii gram at 210° C, and
gave 0.0402 gram Na^SO^.

Calculated for

(C,3Hs06NS)Na + H50.

I.

Found.

II.

H.O

Na

5-19
6.99

5-53
6-93

5-49
6.82

b. The Potassium Salt. — The potassium salt was obtained
in the form of fine white needles which were too small to indi-
cate the form of crystallization. They became opaque on ex-
posure to the air.

I. 0.2 118 gram substance lost 0.0014 gram at 210° C, and
gave 0.0546 gram K^SO^.

Chloride of Paranitroorthosulphobenzoic Acid. 249

II. 0.2041 gram substance lost 0.0013 gram at 210° C, and
gave 0.0518 gram K„SO^.

Calculated for
(C,3H80,XS)K.

1

Foil

ind.

II.

11-33

II

.63

11.46

K

c. The Magnesium Salt. — The magnesium salt was obtained
in the form of tabular monoclinic crystals having a marked
pearly luster. Some of the crystals measured nearly a centi-
meter in length. They appear to undergo no change on ex-
posure to the air.

I. 0.1940 gram substance lost 0.0408 gram at 210° C, and
gave 0.0294 gram MgSO^.

II. 0.1997 gram substance lost 0.0425 gram at 210° C, and
gave 0.0303 gram MgSO,.

Calculated for

Found.

(C,,H80oNS)5Mg + 9JH2O.

I.

II.

H,0 21.17

21.03

21.28

Mg 3-83

3.88

3-90

d. The Calcium Salt. — The calcium salt was obtained in the
form of thin, pearly plates having no regular bounding planes.
They become opaque on exposure to the air and crumble to a
white powder.

I. 0.1373 gram substance lost 0.0096 gram at 210° C, and
gave 0.0280 gram CaSO,.

II. 0.1199 gram substance lost 0.0082 gram at 210° C, and
gave 0.0242 gram CaSO^.

Calculated for

Found.

(Ci3H80oNS)2Ca +3HjO.

I.

II.

H,0

7-65

6.99

6.88

Ca

6.13

6.44

6.39

e. The Lead Salt. — The lead salt was obtained in clusters of
small, tabular, monoclinic crystals, which became opaque
verj^ slowly on exposure to the air.

I. 0.2 12 1 gram substance lost 0.0219 gram at 210° C, and
gave 0.07 II gram PbSO^.

II. 0.2039 gram substance lost 0.0213 gram at 210° C, and
gave 0.0699 gram PbSO^.

III. 0.1543 gram substance lost'o.oi66 gram at 210° C, and
gave 0.0509 gram PbSO^.

250 Hollis.

Calculated for

Found.

(C„H806NS)5Pb+5jH50.

I.

II.

III.

H,0 10.78

10.32

10.44

IO-75

Pb 25.25

25-43

25-95

25-23

The copper salt underwent decomposition on evaporation.

The Action of Phosphorus Pentachloride on the Sodium Salt of
Paranitroorthobenzoylbenzenesulphonic Acid.

The sodium salt and phosphorus pentachloride in the pro-
portion of I molecule to 1.5 were mixed by grinding together
in an evaporating dish. There was no evidence of action,
even upon adding a considerable quantity of phosphorus oxy-
chloride, but on heating there was slight action.

The heating was continued for about ten minutes, and the
pasty mass was then treated with a considerable volume of
cold water. Most of the material dissolved, but a part hard-
ened to a solid mass. After carefully washing with water
this material was washed with absolute alcohol, dissolved in
benzene, and crystallized out b}^ adding an equal volume of
anhydrous ether. The product separated out as clusters of
small, light-colored crystals, which melted at 174°-! 76° C.
(uncorr. ) and as a scale, around the sides of the beaker, which
melted at i6o°-i70° C. (uncorr.). It was entirely free from
the dark-purple material obtained as an impurity in the prep-
aration of paranitroorthobenzoylbenzenesulphone chloride by
the action of benzene and aluminium chloride.

A considerable portion of the material was insoluble in ben-
zene and melted at 24o°-245° C. (uncorr.).

The method of formation of this material, together with its
melting-point, its solubility in benzene, from which it crys-
tallizes readily upon the addition of absolute ether, indicate
that it is paranitroorthobenzoylbenzenesulphone chloride. The
method of formation from the sodium salt is indicated by the
following equation :

/COCeH, /COC.H,

C.H3NO / + PCI, = C^H^NO/ H- POCl,

\SO,ONa \S0,C1

+ NaCl.

The material melting at i74°-i76° C. was boiled in a flask
with a return-condenser, with an excess of dilute hydrochloric

Chloride of Paranitroorthosulphobenzoic Acid. 251

acid until it was completely dissolved. This required seven
hours. The solution was filtered and evaporated to dryness
on a water-bath, and the heating continued until all hydro-
chloric acid was driven off. The product was a dark solid,
similar to that obtained by the action of acid on paranitro-
orthobenzoylbenzenesulphone chloride. An excess of barium
carbonate was added to an aqueous solution of the product,
the excess of carbonate filtered off, and the solution, which
had the characteristic bitter taste of the barium salt of para-
nitroorthobenzoylbenzenesulphonic acid, evaporated under a
bell-jar. On evaporation the solution yielded a small amount
of a crystalline barium salt.

The formation of paranitroorthobenzoylbenzenesulphonic
acid by the action of hydrochloric acid on the product of the
action of phosphorus pentachloride on the sodium salt of para-
nitroorthobenzoylbenzenesulphonic acid, and its conversion
into the barium salt confirms the view already expressed that
the action of phosphorus pentachloride on the sodium salt
gives the sulphone chloride.

The Action of Concentrated Ammonia on Paranitroorthobenzoyl.
henzenesulphone Chloride.

As the result of several experiments it was found that, by
heating the chloride in a sealed tube for two or two and a
half hours in a water-bath, it is mainly converted into a clear,
granular product, which melts at 234° C. (uncorr.).

A small amount of a dark, high-melting product is also
formed as a thin coating, and can easily be removed mechanic-
ally or dissolved in alcohol, which dissolves it readily without
dissolving the main product.

The material thus prepared is obtained in the form of a
light-green, granular powder, having a constant melting-
point of 234° C. (uncorr.). The substance contains no chlo-
rine.

I. 0.2014 gram substance gave 15.81 cc. N.
II. 0.1970 gram substance gave 15.67 cc. N.

III. 0.2075 gram substance gave 0.1756 gram BaSO^.

IV. 0.201 1 gram substance gave 0.1692 gram BaSO^.

Calculated for

I.

9.72

9.86

II. II

11.60

Mollis.

Found.

II.

N 9.72 9.86 9.99

S II. II 11.60 11-55

The results of analysis, together with those described in the
following section, indicate that the main product of the action
of concentrated ammonia on the chloride is the lactin of para-
nitroorthobenzoylbenzenesulphonic acid. The reaction by
which it is formed is represented as follows :

/CsH,

COC H C

C,H3N0/ ' ' + NH.OH = C.H^NO/ ^N +

^SO.Cl ^so/

HCl + 2H,0.

The lactim is insoluble in water, only slightly soluble in
alcohol and readily soluble in benzene.

The formation of the lactim of the sulphonic acid by the
action of concentrated ammonia agrees with the formation of
the lactim of orthobenzoylbenzenesulphonic acid by the action
of dry ammonia gas on the sulphone chloride as observed by
Remsen and Saunders.'

The Action of Concentrated Ammonia oyi the Lactim of Para-
nitroorthobenzoylbenzenesulphonic Acid.

The presence of a red-colored, amorphous product, melting
above 275*^ C. (uncorr.), with the lactim formed b}^ the action
of ammonia on the chloride, together with the fact that the
amount of this product was increased as the length of time of
heating was increased, indicated that another pi'oduct was
formed by the continued action of ammonia. A considerable
quantity of this material was prepared by heating some of the
paranitroorthobenzoylbenzenesulphone chloride in a .sealed
tube until the only product consisted of the red-colored sub-
stance desired. It was found necessary to heat it to the tem-
perature of the water-bath for twenty-four hours in order to
effect this transformation, while two and a half hours were
sufficient to transform the sulphone chloride into the lactim,

1 Loc. cit.

Chloride of Paranitroorthosulphobenzoic Acid. 253

The product is insoluble in water, but dissolves readilj^ in
absolute alcohol, giving a red solution with a marked green
fluorescence. It is thrown out of solution by adding a con-
siderable volume of water.

On evaporating the alcoholic solution it is deposited as a
red-colored crust which seems to possess no crystalline struc-
ture.

0.2150 gram gave 19.24 cc. N = 11.24 per cent N.

0.1615 gram gave 0.1200 gram BaSO^ = 10.20 per cent S.

The results of the analysis show that while the percentage
of sulphur remains about the same as in the lactim, the per-
centage of nitrogen is increased, but not to an amount corre-
sponding to the composition of any substance likely to be de-
rived from the lactim by the further action of ammonia.

These results, together with the impossibility of obtaining
the product in crystalline condition and its properties gener-
ally indicate that it is probably not a definite chemical com-
pound, and that the lactim probably undergoes decomposition
by the further action of ammonia.

77/1? Action of Dilute Hydrochloric Acid on the Lactim of Para-
nitroorthoberizoylbenzenesulphonic Acid.

The action of hydrochloric acid on the lactim was first tried
by boiling in a flask, provided with a return-condenser, with
an excess of acid. The lactim showed but little change after
boiling with the acid for thirty hours. The acid was colored
j'ellow, but this was found to be due to solution of the lactim.
By evaporating off the acid, the lactim is recovered with its
melting-point unchanged.

By heating the lactim with a large excess of hydrochloric
acid in a closed tube to \^d'-\']^ C. in a furnace for five
hours, about half of the lactim is dissolved and is not deposi-
ted on cooling. On heating to 200° C. for seven hours longer,
all of the lactim goes into solution, and is not deposited on
cooling, and the acid has a dark-yellow color. On evapora-
ting the filtered acid solution, a yellow, crystalline product is
obtained, which has not a constant melting-point. The melt-
ing-point, immediately after pressing out between filter-paper,
is ioo°-i6o° C. (uncorr.), and it is charred by heating to 210°

2 54 Hoi lis.

C. (uncorr.) in an air-bath. If, however, it is first carefully
dried, it appears to melt at a much higher temperature.

This indicates that the product is a salt which melts in its
water of crystallization.

Analysis of a sample carefully dried :

0.2009 gram gave 14.33 cc. N.

0.1692 gram gave 0.1264 gram BaSO^.

Calculated for
/COCeHs
CeHgNOjC . Found.

^S020NH4

N 8.64 8.95

S 9.88 10.24

The results of analysis indicate that the product is the am-
monium salt of paranitroorthobenzoylbenzenesulphonic acid.
The transformation takes place according to the following
equation :

/ C / /COC.H,

C6H3NO/ ^N + 2H,0 = C,H3N0/

\S0/ \SO,ONH,

The ammonium salt thus obtained has generally the form
of a yellow cr)^stalline powder, but under the conditions ex-
isting in one of the experiments, a few thick, needle-shaped
crystals about a centimeter long were obtained. It dissolves
readily in water.

Suvtmary .

The principal results obtained in the foregoing investiga-
tion may be briefly stated as follows :

By using phosphorus pentachloride in the proportion of 2.5
molecules to i of the anhydrous acid potassium salt and heat-
ing for five hours under the conditions indicated, the unsym-
metrical chloride is the only product.

This may be crystallized readily at the temperature of the
laboratory by using ligroin (90°-! 25°) as the solvent, provi-
ded the impurities are first removed by washing with ligroin
(5o°-8o°).

The action of benzene and aluminium chloride on the sym-
metrical and on the unsymmetrical chloride gives, in both
cases, paranitroorthobenzoylbenzenesulphone chloride.

Stereoisomers and Racemic Compounds. 255

The action of hydrochloric acid, concentrated or dilute,
dilute sulphuric acid, water, and alcohol on paranitroortho-
benzoylbenzenesulphone chloride is the same. The product
formed is, in each case, paranitroorthobenzoylbenzenesul-
phonic acid.

The action of phosphorus pentachloride on the sodium salt
of paranitroorthobenzoylbenzenesulphonic acid gives rise to
the formation of paranitroorthobenzoylbenzenesulphone chlo-
ride identical with that from which the acid was derived by
the action of acids or water.

The action of concentrated ammonia on paranitroorthoben-
zoylbenzenesulphone chloride for a limited length of time
gives the lactim of paranitroorthobenzoylbenzenesulphonic
acid.

The further action of concentrated ammonia gives a sub-
stance of indefinite composition, which probably indicates a
decomposition of the lactim first formed.

The continued action of concentrated hydrochloric acid at a
high temperature in a sealed tube converts the lactim into the
ammonium salt of paranitroorthobenzoylbenzenesulphonic
acid.

Contribution from the Kent Chemical Laboratory of the University of Chicago.

STEREOISOMERS AND RACEMIC COMPOUNDS.

By Herman C. Cooper.

/. Solubility of Stereoisomers in an Indifferent Active Solvent.

The possibility of a difference in solubility of two optical
isomers in an active solvent has been recognized ever since
the researches of Pasteur." In a recent paper** the writer, to-
gether with Heinrich Goldschmidt, who first directed his at-
tention to the matter, presented experimental evidence indi-
cating that the two optically active carvoximes have the same
solubility in ^-limonene. Tolloczko'' had by a different
method previously come to similar conclusions in the cases of
the tartaric acids in amyl alcohol and the mandelic acids in

1 Ann. chim. phys. [3], 38, 437; Cf. also Van 't Hoff-iEiloart, Atoms in Space,
1898, p. 45.

2 Ztschr. phys. Chem., 26, 711.
^ Ibid., 20, 412.

256 Cooper.

levulose solution. Kipping and Pope/ however, announce
that, on allowing a racemic mixture to crystallize from an
optically active solution, the first fractions show a preponder-
ance of crystals of one of the isomers. Thus, the first crys-
tallization of sodium ammonium racemate from aqueous dex-
trose solution at a temperature below the transition-point was
found to consist chiefly of dextrotartrate. As this seems to
suggest a difference of solubility of the two active tartrates in
dextrose solution, it appeared desirable to use the same sim-
ple method employed in the carvoxime-limonene test"^ to ob-
tain more light on this matter.

On account of the rather large solubility of the sodium am-
monium tartrates in water and their tendency to weather, the
stable sodium hydrotartrates were first examined. In the
light of the present structural theory of optical isomers it is
very unlikely that the addition of an NH3 group each to both
isomers would alter their relative behavior towards an active
solvent. The probability of electrolytic dissociation of tar-
trates in such a solution renders this all the less likely.

Sodhim Hydrotartrates in Aqueotis Dextrose Solution. — The
dextrotartrate was prepared by mixing the theoretical amounts
of sodium carbonate and ordinary c. p. tartaric acid in water;
the laevo salt in a similar manner from /-tartaric acid ob-
tained by the Pasteur- Anschiitz crystallization method.'
After recrystallization the salts were tested as to rotatory

1 Proc. Chem. Soc, 1898. 113.

2 Goldschtnidt and Cooper : Loc. cit.

3 A careful comparison of the three well-known Pasteur methods has shown the
crystallization process to be the most reliable in securing a satisfactory yield about
whose rotatorj' power no anxiety need be felt. By the improved cinchonine method
(Ber. d. chem. Ges., 29, 42) much time is consumed in the recovery and purification
of the racemic acid and cinchonine unless one is working on a large scale, while
with a little care a concentrated solution of Scacchi salt can after a short period in a
cold room be made to yield homogeneous crj'stals of 1-5 grams each. The first one
that can be crj'stallographically identified as laevo should be used to prepare a cal-
cium-tartrate solution, and the neat Anschiitz test (Ann. Chem. (Liebig), 226, 193) at
once applied to all the other crystals. If the sample is taken from different parts of
the crystals, the ones so recognized as laevo will be found, after recrystallization
from 60 per cent alcohol, to furnish a tartrate of unquestioned purity, from which the
laevo acid is easily obtained by treatment with lead acetate and hydrogen sulphide.

Sowing the original solution with lae%'0 cr}'stals is of advantage for the first one
or two crops, but supersatu ration with reference to the dextrotartrate soon becomes so
great that laevo crystals are dissolved while dextro crj'stals are formed. For this
reason it is better to sow dextro and laevo crystals simultaneously at different places
in the solution.

Stereoisomers and Racemic Compounds. 257

power with a thoroughly reliable Laurent half-shadow polarim-
eter.

1 . ^-XaC^H.Oe -f~ H„0. 1 .5350 grams dissolved in water to
25CC.; f=:6.i40o; /= 21'' ; /= 2dm ; or ^ -f~2''42'.3 ; [or]!,' rr
+22'. 03.

2. /-NaC^H.Oe + H„0. 1.5350 grams dissolved in water to
25 cc. ; 0^=- 6.1400 ; /= 19". 5 ; /=: 2dm ; oc^iz — 2''42' ; [a']^^^
—21'. 98.

A comparison of these figures with the table of Thomsen'
shows that the substances may be considered perfectly pure.
The dextrose solution used possessed a density of 1.14, a
strength of 32.5 per cent, and a rotacorv power of [«^]d =
53°.8.

Weighed quantities of tartrate and dextrose solution were
sealed up in small glass tubes and the temperature determined
at which complete solution took place.' By w^orking with a
No. 20 beaker-glass and carefully avoiding disturbing air
currents the temperature could easilj^ be held constant to 0°. i
below 50°, and to at least o°.2 between 50"" and 70°. The
tubes were allowed to rotate about 60-70 times a minute. In
cases where the concentration, and consequently the solution-
temperature, was high the question as to just when complete
solution took place was decided b\^ removing the tube and al-
lowing it to remain several hours at room temperature. If all
solid particles had disappeared, supersaturation resulted and
no separation of solid matter followed ; otherwise the tube
was replaced and the test continued. A table of results fol-
low^s :

d- Tartrate in Dextrose Solution.

Grams tartrate
Grams dex- to loo grams Solution

Gram tartrate. trose solution. dextrose solution. temperature.

0.1782 2.3202 7.68 32°. 9
0.1984 1-8949 10.47 43°-6-f-
0.1946 1. 1200 17-38 61°. 6

1 J. prakt. Chem. [2], 31, 85.

2 For description of apparatus see Ztschr. phys. Chem., 26, 713; and also Fig.
125, Ostwald-Walker's Physico-chem. Measurements (1894).

258

Cooper.
I- Tartrate in Dextrose Solution.

0.1756

2.8700

6.12

25°. 2

0. 2006

2.5330

7.92

34°.o

0.1998

1.9066

10.48

43°-7

0-I943

1.1301

17.19

6i°.i

The parallelism of the results in the two cases is better
shown by plotting them as curves. Let the figures in the
third column, representing solubility, be the ordinates and
those in the fourth column, representing the corresponding
temperatures, be the abscissae. The crosses indicate <f-tar-
trate, the circles /-tartrate.

40 4s so

Tem/ierafi/re

As a further check on the results we may apply the solu-
bility formula, S=a^ bt-\-ct^, which, using the values at
25°-2, 34°-o, and 43°-7. becomes 5"= 3.72 -f 0.01443/ +
0.003211/° for dextrotartrate. Interpolating for 32°. 9 we have
6"= 7.67. 7.68 was found experimentally for /-tartrate. It
is plain that there is no justification for the assumption of two
separate curves and we must conclude that there is no differ-
ence in solubility.

Sodium A7nmo7iiu7n Tartrates in Aqueous Dextrose Solution.
— A few experiments were then similarly made with the
sodium ammonium tartrates. Each of these salts was re-
crystallized from 60 per cent alcohol, the solution being agita-

Stereoisomers and Racemic Compounds. 259

ted to produce small crystals, and the resulting crystals were
washed with alcohol and dried first on filter-paper and then
a few minutes in a vacuum desiccator. In each experiment
nearly equal proportions of dextro and laevo salt were used
and the two tests carried out simultaneously (temp, as under
I). After subsequent cooling each experiment was repeated
(II).

Exp. I. — Material obtained from Neutralizing the Previously
Prepared Hydrotartrates with Ammonia.

Grams tartrate
Gram Grams dex- to loo grams Solution temperature.

NaNH4C4H406 + 4H,0. trose sol. dextrose sol. I. II.

Dextro 0.6668 1.0846 6.15 27°. 3 27°. 4

lyaevo 0.6682 1.0870 6.14 27°. 6 27^.6+

Exp. II. — Material from Freshly Separated Tartrates.

Dextro 0.5222 1.0652 4.90 22°. i 2i°.9

Laevo 0.5300 1-0733 4.94 21°. 8 2i°.9

Exp. III. — Material as in Exp. II.

Dextro 0.4918 0.9886 4.97 22°. 2 22". 2

Laevo 0.4920 0.9891 4.97 22°. 15 22°. 2

The slight variation in the results seems to be due to the
rather large experimental error, anticipated above, and we
are hardly justified in assuming any considerable difference in
solubility. It is therefore very probable that a solution of an
externally compensated mixture of the sodium ammonium
tartrates, in a concentration strong enough to cause crystal-
lization, will in time yield practically equal quantities of the
two modifications. Nevertheless, if the dextrose molecules
exert even the slightest influence, so that the first crystal
molecule formed is dextro, that individual will have the same
effect on the crystallization as the introduction of a dextro
crystal. No intrusion on the field of Messrs. Kipping and
Pope is planned, but it is to be hoped that they will ascertain
whether a laevo-rotatory solvent has the opposite effect from
that of dextrose solution.

//. Properties of Inactive Mixtures.
Melting-point. — The following data supplement the inter-

26o Cooper.

esting work of Centnerszwer.' Sodium hydrotartrate decom-
poses at 234°, a point sharply indicated by a sudden rise of
substance in the m. p. tube. The racemate decomposes at
219°, and a mixture of approximately equal parts of the
optical isomers at 222°.

A mixture of approximately equal parts of the active carv-
oximes was found to melt at the same temperature as inactive
carvoxime; viz., 93°, A slight shrinking was to be observed
at 72°, the melting-point of the active body.

Solubility. — On mixing equal amounts of the active sodium
h3'drotartrates in water, a cloudy precipitate of racemate ap-
pears and does not disappear till the temperature of the solu-
tion of the racemate is reached. A similar mixture of the act-
ive carvoximes in aqueous alcohol gives no precipitate of
racemic compound, but, nevertheless, has the same solubility
as an amount of racemic carvoxime equal to the weight of the
mixture.

///. Partial Racemisrn.

The credit of having established the existence of partial
racemic compounds must be ascribed to Ladenburg, who
identified racemic quinine pyrotartrate" as the first example.
Other examples have been subsequently announced by Laden-
burg and Doctor,' and by Pope and Peachey.^ It will be
noticed that there is no essential difference between them,
each being made up of two components which possess the
same chemical composition, differing only as -\-A -\- B and
-\-A — ^ or -f-^ + ^ and — A-\-B, in which A represents
an acid, B a basic radical. Is it not possible, however, for a
racemic compound to exist whose active components are not
chemically equivalent ? When one considers the facility
with which some optical isomers unite to form racemic com-
pounds of distinctly different physical properties, the question
easily arises whether a slight modification of one isomer, such
as substitution in a position remote from the asymmetric car-
bon atom, necessarily renders racemic association impossible.

1 Ztschr. phys. Chetn., 29, 715.

2 Ber. d. chera. Ges., 31, 524, 937.
^ Ibid., 3i, 1969.

4 Ztschr. Kryst. u. Min., 31, 11.

Obituary. 261

Such a case, if discovered, would certainly broaden our ideas
of racemic bodies. Reasoning somewhat in this way, Kiister'
has suggested the possibility of chlorbenzoyl-tf-tartrate and
brombenzoyl-/-tartrate uniting to form a partial racemate.

In Pasteur's notable monograph^ entitled " Nouvelles
Recherches," ammonium bimalate is said to form a definite
compound with dextroammonium bitartrate, not, however,
with laevoammonium bitartrate. This discovery of a half
century ago has apparently been frequently overlooked, no
mention of it being found in Bischoff-Walden's " Stereo-
chemie" or Van 't Hoff-Eiloart's " Arrangement." The com-
pound was found to consist of i molecule of ^-ammonium bi-
tartrate and I molecule of /-ammonium bimalate. Inasmuch
as the atomic difference between the two molecules is very
slight, it seems quite likely that we have here to deal with a
case of partial racemism as above suggested. A repetition
and extension of Pasteur's experiments is planned, covering
all the tartro-malic compounds, and the much discussed " cri-
teria" of racemic compounds will be carefully applied. Some
preliminary experiments with sodium bitartrate and sodium
bimalate have disclosed interesting relations.

OBITUARY.

CARL FRIEDRICH RAMMELSBERG.

The long and useful life of Carl Friedrich Rammelsberg
ended on December 28th of the past year. He was born in
Berlin, April ist, 1813, and after a thorough school training
spent five years as an apothecary. He then matriculated at
the university and devoted himself to physics, chemistry,
mineralogy, and botany under the most distinguished teach-
ers of that day, working in the laboratory of Mitscherlich,
Later he established the first laboratory specially devoted to
the instruction of students in inorganic analysis. He became
in succession privatdocent, extraordinary, and ordinary pro-
fessor in the University. Meantime his marvelous industry
showed itself in the publication of numerous papers on mineral
chemistry, the number of these alone amounting to more than
150. He made also valuable investigations in many branches

1 Ber. d. chem. Ges., 31, 1853.

2 Ann. chim. phj-s. [3], 38, 460.

262 Notes.

of pure inorganic chemistry, and as an excellent crystallog-
rapher did much to further the study of crystalline form as
an essential part of descriptive chemistry. The list of his
special treatises, handbooks, and introductions is a long one
and many of them even now have a real value as works of ref-
erence and well illustrate the broad view which he took of
his own favorite branches of science. He was able to pursue
his laboratory work long after the age when most chemists are
obliged to content themselves with only looking on at the
progress of their science. Personally he was much beloved
by his pupils and was conscientious as a teacher as well as an
investigator. The writer of this brief notice, as one of Ram-
melsberg's pupils, offers these words of appreciation of the
man and of his work. w. G.

NOTES.
Polonium and Radium.

Some years ago Becquerel, while working with uranium
and some of its salts, found that certain of the salts, although
they are not fluorescent, nevertheless have the power of
emitting rays which are different from the Roentgen rays.
These new rays have the power of rendering gases through
which they pass conductors of electricity and of producing
impressions on photographic plates. They are also capable
of being transmitted through opaque bodies, but suffer greater
absorption than the Roentgen rays.

Shortly after Becquerel's work, Schmidt found that thorium
and its salts emit the same kind of rays as uranium and
its salts, but that the former are less intense than the latter.

While investigating pitchblende and other minerals closely
allied to it, which contain uranium and thorium, M. and
Mme Curie' discovered the new substance which they called
polonium, after the native country of Mme. Curie. They
called the property of emitting Becquerel rays "radioactivity",
and found that the sample of pitchblende with which they
were working was two or three times as radioactive as ura-
nium. Since the salts of uranium are less active than metallic
uranium, they concluded that the great radioactivity of pitch-
blende is due to the presence of a small amount of some
strongly radioactive substance. They passed h5'drogen sul-
phide into an acid solution of the pitchblende. The uranium
and thorium remained in solution, and besides lead, bismuth,
copper, arsenic, and antimony, a very active substance was pre-

1 Compt. rend., 127, 175 (1898) ; Chera. News, 78, 40 (1898).

Notes. 263

cipitated. The active sulphide is insoluble in ammonium sul-
phide, which separated it from arsenic and antimony. The sul-
phides insoluble in ammonium sulphide were dissolved in
nitric acid, and the lead precipitated with sulphuric acid.
Some of the active substance is carried down with the lead,
and can be covered by treating the lead sulphate with dilute
sulphuric acid, which dissolves the active substance. There
were then in solution the active substance, bismuth and cop-
per. Ammonia precipitated the first two completelj^, thus sepa-
rating them from the copper. It was impossible to separate the
active substance from bismuth in the wet way. On dissolving
them both in nitric acid and adding water, it was found that
the' portions first precipitated are by far the most active.
Further, when the mixed sulphides from pitchblende are
heated in a vacuum in a glass tube to about 700°, the active
substance sublimes in the portion of the tube heated to 250°-
300°, while the bismuth remains in the warmer part of the
tube. By these methods the investigators obtained a sub-
stance which was 400 times as active as uranium. Specimens
of it were sent to Demargay to be examined spectroscopically,
but his results were unsatisfactory.

While working on polonium M. and Mme. Curie' discov-
ered a second new radioactive substance, closely allied to
barium and different from polonium, which they called
radium. This new radioactive substance is obtained from
pitchblende together with barium, and it has not been possi-
ble to separate it from barium. It is not precipitated by hy-
drogen sulphide, ammonium sulphide, nor ammonia ; its sul-
phate is insoluble in w^ater and acids ; its carbonate is insolu-
ble in water ; the chloride is very soluble in water, but in-
soluble in concentrated hydrochloric acid and in alcohol.
The substance, as first obtained by its discoverers, was in the
form of the chloride and then had a radioactivit}^ 60 times as
■great as that of uranium. On dissolving the chloride in
water and precipitating with alcohol, the portions first precipi-
tated are the most active. In this way a substance was
finally obtained which was 17000 times as radioactive as
uranium. Demarjay" examined the spectrum of this sub-
stance and found in it the barium lines, the platinum lines due
to the electrodes, the calcium and lead lines, which were very
weak, probably due to impurities, and a series of new lines
which were fully as intense as the barium lines, and which
could not possibly belong to any of the known elements. The
new lines in the spectrum were comprised between A- = 4826.3

iCompt. rend., 127, 1215 (1898) ; Chem. News, 79, i (1899).

2 Compt. rend., 127, 1218 (1898) ; Ibid., 129, 716 (1899) ; Chem. News, 29,13 (1899) ;
Ibid., 80, 269 (1899).

264 Notes.

and A. rr 3649.6. The strongest new line, which was as strong
as the strongest barium line, had A. = 3814.7. The results of
the spectroscopic examination, together with the fact that
barium and its compounds are not in the least radioactive, led
M. and Mme. Curie to the conclusion that they had a new
substance to deal with.

The atomic weight' of the metal contained in some of the
most active specimens of radiferous barium chlorir'e was de-
termined with the following results :

a. M. Ba.

3000 140.0 138.1

4700 ^40. 9 137-6

7500 145.8 137.8

a represents the activity of the chloride, the activity
of uranium being taken as i, tT/ represents the atomic weight
of the metal in the radiferous chloride, and Ba represents the
atomic weight of barium from pure, inactive barium chloride,
whose atomic weight was determined each time that the metal
in the radiferous chloride was determined. The atomic
weights were determined by estimating the amount of chlo-
rine in the anhydrous chlorides with silver nitrate.

Becquerel rays and the rays from polonium and radium
seem to be essentially the same in character, but they differ
in intensity. The rays from radium are the strongest, those
from thorium the weakest. The radium rays will produce an
impression on a photographic plate in half a minute, while un-
der the same conditions the uranium rays require an hour to
produce the same impression. Rays from polonium and
radium excite fluorescence in barium platinocyanide, weaker
to be sure than that caused by Roentgen rays, but uranium and
thorium rays excite no fluorescence at all on account of their
weaker radioactivity. Radioactive substances also have the
power of inducing radioactivity in inactive substances, and
this induced radioactivity continues for several days after the
originally radioactive substance has been removed. In this
respect Becquerel rays differ markedly from Roentgen raj^s
which produce a secondary effect in bodies only as long as
the rays strike such bodies.

Becquerel rays seem to have the power of inducing chem-
ical action.' It was observed that when bottles containing
radiferous barium chloride were opened, the odor of ozone
was very perceptible. This odor was dissipated after the
bottle had stood open for some minutes, but was noticeable
again when the bottle was opened after having been closed for

1 Compt. rend., 129, 760 (1S99) ; Chem. News, 80, 2S1 (1899).

2 Compt. rend., 129, 1S23 (1899).

Notes. 265

some time. Also, the glass of bottles in which the chloride is
kept assumes a violet color where it comes in contact with the
salt. Villard' noticed a similar effect when glass is subjected
to the action of Roentgen rays, while at the same time it is
protected from the cathode rays. It is concluded that this
coloration of the glass is due to the oxidation of manganese
which is contained in it. Further, the action of Becquerel
ra3-s on barium platinocyanide seems to be of a chemical na-
ture. The salt under the effect of these rays becomes fluo-
rescent and turns yellow. It then loses its fluorescence and
becomes dark-brown. If now it is exposed to the sunlight, it
again acquires the property of becoming fluorescent when
struck b}' Becquerel rays.

To account for the continuous disengagement of energy
from radiferous bodies, several views have been advanced. It
might be due to a phosphorescence of very long duration,
caused b}^ the action of light, or it might be due to an emis-
sion of matter accompanied by a loss of weight of the radifer-
ous bodies. Again, it might be a secondary emission pro-
voked b\' rays which are constantly in existence in space and
which are absorbed only by certain elements.

Quite recently, M. Debierne" has obtained another radioac-
tive substance from pitchblende, which is closely allied to
titanium in its chemical properties. It differs from radium
in that it is not luminous in the dark, while radium is lumi-
nous, c. E. c.

AsytnTuetric Optically Active Nitrogen Compounds.

Messrs. Pope and Peachey^ have recently published an in-
teresting article on the above subject. From this the follow-
ing extracts are taken :

"The only direct evidence pointing to the existence of
asymmetricall}^ optically active nitrogen compounds is Le
Bel's observation* that on cultivating Penicillium glaiictim in
solutions of isobutyipropjdethylmethylammonium chloride the
liquid acquires a rotatory power of — o°25' or — 0^30' under
favorable conditions. The value of this important observa-
tion is, however, considerably lessened hy the fugitive nature
of the optical activity and by the failure of Marckwald and
von Droste-Huelshoff* to confirm I^e Bel's results. (Le Bel
has recently replied to Marckwald and von Droste-Huelshoff's
criticism,^ and has confirmed his previous results.)

1 Cotnpt. reud., 129, SS2 (1S99).

2 Ibid., 129, 593 (1899).

3 J. Chem. Soc, December> 1S99.

4 Compt. rend., 1S91, 112, 724.

5 Ber. d. chem. Ges., 32, 560.

6 Corapt. rend., 129, 548.

266 Notes.

" Many futile attempts have been made to directly resolve
quaternary bases of the type N(OH)XjX5X3X^ into optically
active antipodes by means of optically active acids. Thus
Marckwald and von Droste-Huelshoff' attempted to resolve
I^e Bel's base by the aid of tartaric, camphoric, and mandelic
acids, whilst Wedekind" endeavored to resolve a-benzojd-
phenylallylmethylammonium hydroxide by means of tartaric
and camphoric acids ; in no case, however, was an optically
active base obtained.

" A consideration of the facts led to the opinion that the fail-
ure of these and other attempts had its origin in the facility
with which tetralk^'laramonium salts are decomposed by water
and converted into tertiary base and alcohol ; we, therefore,
prepared o'-benzylphenylallylmethylammonium iodide by
Wedekind's^ method and were successful in resolving it into
isomeric optically active bases by using hj^droxyl-free solvents
containing only small quantities of water. A number of
methods, differing in detail, were applied, but we ultimately
adopted the following process as affording the best results :

" Carefull}^ purified a-benzylphenylallylmethylammonium
iodide was mixed with a molecular proportion of the anhy-
drous silver salt of Reychler's dextrocamphorsulphonic acid
and boiled for an hour or so on the water-bath with a mixture
of about equal parts of acetone and, ethylic acetate, a few
drops of water being added when necessary. After separa-
ting silver iodide from the gummy solution by filtration the
solvent was distilled off, and, on cooling, the residue solidi-
fied to a crystalline mass consisting of a mixture of dextro-
andlaevobenzylphenylaIlylmeth3damraonium dextrocamphor-
sulphonate.

" By fractionally crystallizing the mixture of dextrosul-
phonates from boiling acetone the less soluble constituent,
dextro-o'-benzylphenylallylmethylammoniura dextrocamphor-
sulphonate, was readily obtained in colorless, diamond-shaped
plates melting at 169°-! 70°. "

The authors show that the molecular rotatory power of the
basic radical of this salt is -|-i50°.

The corresponding laevo salt was obtained from the acetone
mother-liquors, and this was found to have a marked laevo
rotatory power.

From the two dextrosulphonates the corresponding iodides
and bromides were obtained.

In concluding their article the authors say :

' ' In the present paper it is proved that quaternary ammo-

1 Loc. cit.

2 Ber. d. chem. Ges., 32, 517.

3 Loc. cit.

Reviews. 267

nium derivatives in which the five substituting groups are
different, contain an asymmetric nitrogen atom which gives
rise to antipodal relationships of the same kind as those corre-
lated with an asymmetric carbon atom. The method which
has enabled us to deal with quaternary bases is now being
applied to various other types of substituted ammonium de-
rivatives in order to ascertain the stereochemical nature of
pentad nitrogen. We hope shortly to be in a position to pub-
lish results obtained with sulphonium derivatives of the type
SX,X„XJ." I. R.

REVIEWS.

Lessucres et leurs principaux derive;s. Par L. Maouenne, Pro-
fesseur au Museum d' Histoire Naturelle. Paris : Georges Carrd et
C. Naud, editeurs. 1900. 1032 pp.

The author of this handbook has done chemists a service
b}^ compiling from the great mass of papers appearing within
the last few years on the sugars and closely allied substances —
largely due to the labors of E. Fischer and his pupils and co-
workers— a general resume of our present knowledge in the
field in question. Not only are the general principles of
stereoisomeric chemistry applied systematically to the classi-
fication and nomenclature of the sugars, but the preparation
and properties of the now numerous substances of this class
are described with a very fair degree of detail, considering the
moderate size of the book, and its value is greatly enhanced for
the practical worker by copious references to the original
papers which have been collated, French, Russian, and other
sources being drawn upon as well as German. The transfor-
mations by hydrolj^sis, fermentation, etc., are gone into in
brief but intelligible fashion, connecting the sugars with each
other and with their chief derivatives of other classes, and
methods of determination for the principal sugars are dis-
cussed in their practical bearings. The notice taken of some
allied substances, such as starch and cellulose, seems to be
hardly in proportion to the work upon them which has been
done in recent years, though there are references to the more
important memoirs. In agreeable contrast with the usage
of most French writers, the author has appended a convenient
index, as well as the usual table of contents. j. w. m.

Modes OpERAToiRiSs des essais du Commerce et de ^'Industrie.
Par Iv. CUNIASSE et R. Zwilung, Chimistes-Experts de la Ville de
Paris. Paris : Georges Carr^ et C. Naud, Editeurs. 1900. 302 pp.

In the preface to this little book, by M. Ch. Girard, it is
suggested that it is intended for the use of young men who

268 Reviews.

expect to enter industrial laboratories, and is to occupy an in-
termediate place between the large treatises for professional
men and the small text-books for beginners. There is in-
cluded much good matter, in general clearly presented and in
highly condensed form, but condensation has been carried so
far that, for many of the topics treated of, the work can hardly
be considered as more than an index, and must prove of small
value in the absence of larger handbooks. Thus, the whole
subject of iron is disposed of in about three and a half small
pages (no notice is taken of steel), glass in a p?ge and a
quarter, fuel in less than three pages, soap in a little more
than three pages, and butter in about a page. Some other
subjects have more space devoted to them, as, for example,
there are ten and a half pages on milk, fifteen pages on sugar,
and nearly twent)'' pages on wine. A few materials are in-
cluded which are not commonly found in the smaller manuals
of this kind, such as wood- and coal-tar creosote, vulcanized
india-rubber, and gutta percha. j. w. m.

Water and Water Supplies. By John C. Thresh, D.Sc. (Lon-
don). Philadelphia : P. Blakiston's Sou & Co. (printed in England).
1900. 431 PP-

A generally well-compiled and well-balanced summary of
the most important facts — geological, chemical, bacteriolog-
ical, and engineering — bearing upon natural water as ob-
tainable for human use. In regard to most of the questions
which have given rise to difference of opinion the author seems to
fairly, and without partisanship, sum up the present state of
our knowledge, as, for instance, in the chapters on the inter-
pretation of water analyses and the so-called self-purification
of rivers. The book is written essentially from an English
point of view^ and would be increased in value if more ex-
tended notice were taken of the investigations made and re-
sults obtained in other countries. The three subjects which
receive distinctly inadequate notice are : the effects of various
kinds of natural waters upon metallic pipes and iron or steel
boilers ; the relations of natural waters to special manufactur-
ing uses, such as brewing, dyeing, and paper-making, and
the effects on streams of special manufacturing refuse ; and
the rapid mechanical filtration of water on the great scale,
aided by coagulants, as now largely practiced in the United
States. J. w. M.

Outlines of Industrial Chemistry. By Frank Hall Thorp,
Ph.D., Instructor in Industrial Chemistry in the Massachusetts In-
stitute of Technology. New York : The Macmillau Company. New
edition, revised. 1S99. 541 pp.

The appearance of a second edition of this work a year after

Reviews. 269

its first publication is a favorable indication of its having
proved acceptable. As the author says in his new pi'eface
that he has limited himself to the correction of errors which
have been noticed, and has made no material change in the
text, there seems to be occasion for little more than a repeti-
tion of the remarks made in a former notice in this Journal
(Vol. 21, p. 181). It is to be hoped that the press of other
work referred to as the reason for not extending or recasting
any parts of the book may not long prevent the bringing out
an edition with such changes and improvements, particularly
in regard to the illustrations, as might easily develop the
work into a very useful manual for students. j. w. m.

Introduction to Physical Chemistry. By James Walker., D.Sc,
Ph.D., Professor of Chemistry in University College, Dundee. New
York and London : Macmillau & Co. 1899. 335 pp.

This work does not aim to be a systematic text-book cover-
ing the whole field of physical chemistry, but treats certain
chapters at considerable length. Dr. Walker states the pur-
pose which he had in mind in writing this book, as follows :
" I have found in the course of ten years' experience in
teaching the subject, that the average student derives little
real benefit from reading the larger works which have hitherto
been at his disposal, owing chiefly to his inability to effect a
connection between the ordinary chemical knowledge he pos-
sesses and the new material placed before him. He keeps his
every-day chemistry and his physical chemistry strictly apart,
with the result that instead of obtaining any help from the
new discipline in the comprehension of his systematic or prac-
tical work, he merely finds himself cumbered with an addi-
tional burden on the memory, which is to all intents and pur-
poses utterly useless. This state of affairs I have endeavored
to remedy in the present volume."

Some of the subjects treated are : The Atomic Theory and
Atomic Weights ; The Simple Gas I^aws ; The Periodic
Law ; Solubility ; Fusion and Solidification ; Vaporization
and Condensation ; The Kinetic Theory and van der Waals'
Equation ; The Phase Rule ; Relation of Physical Properties
to Composition and Constitution ; The Properties of Dissolved
Substances ; Osmotic Pressure and the Gas Laws for Dilute
Solutions ; Methods of Molecular Weight Determination ;
Electrolj'sis and Electrolytes ; Electrolytic Dissociation ;
Balanced Actions ; Rate of Chemical Transformation ; Rela-
tive Strengths of Acids and Bases ; Applications of the Disso-
ciation Theory ; Thermodynamical Proofs.

The chapter on the Phase Rule is by far the clearest and most
concise treatment of this subject which has thus far appeared.

270 Reviews.

Under methods for determining molecular weights, in addi-
tion to those ordinarily employed for vapors and solutions, we
find a brief account of the beautiful method of Ramsay and
Shields, by which the molecular weight of pure liquids can be
determined by measuring their surface-tension. It is unfortu-
nate that this method is too delicate for general laboratory use,
since much of importance would undoubtedly be brought to
light by its further application.

It seems a little out of keeping with the remainder of the
work, that the very defective method of Nernst an^ Loeb
should be recommended for determining the relative veloci-
ties of ions, now that we have methods which are so much
more refined.

The work, as a whole, is admirably written in a clear and
attractive style and can be heartily recommended to any one
who is beginning the study of physical chemistry.

H. c. J.

A Text-Book of Physical Chemistry. By Dr. R. A. Lehfeldt,
Professor of Physics at the East London Technical College. Lon-
don ; Edward x\ruold. 1899 308 pp.

The author points out what is generally recognized, that
the new physical chemistry has not been accorded the hearty
welcome in England which it deserves. " It is time, too, to
appeal for wider recognition in England, where, as yet, not a
single professorship exists to mark the appearance of a new
science that on the continent has long been regarded as wide
enough to require a man's whole energy." A brief quota-
tion from the preface will show what is the aim of this little
book : ' ' The present book is intended to contain what a stu-
dent— with limited time and many subjects to learn — may
usefully read. * * The author hopes that the style adopted
will put the reader, as far as possible, in touch with the con-
stant stream of experimental and theoretical research that makes
physical chemistry at present such a fascinating subject to fol-
low."

The subject is dealt with in seven chapters : Determination
of Molecular Weight ; Physical Constants in Relation to
Chemical Constitution ; The Principles of Thermodynamics ;
Chemical Dynamics of Homogeneous Systems ; Chemical
Dynamics of Heterogeneous Systems ; Application of Ther-
modynamics to Chemical Equilibrium ; Electrochemistry.

The work is clearly written and is quite up to date. The
abbreviation Ostw. for Zeitschrift fiir physikalische Chemie,
is not customary, and is a little perplexing until one consults
the list of abbreviations, since we should naturally think that
this referred to Ostwald's Eehrbuch. But this is of little con-

Reviews. 271

sequence. The book will doubtless contribute much to the
advancement of physical chemistry wherever it is used.

H. c. J.

Optical Activity and Chemical Composition. By Dr. H. L,andolt,
Professor of Chemistry in the University of Berlin. Translated with
the author's permission by John McCrae, Ph.D. Ivondon and New
York : Whittaker & Co. 1899. 158 pp. Price, |i.oo.

This is a translation of the eighth chapter of the first vol-
ume of Graham-Otto's " Lehrbuch der Chemie." Professor
Landolt is the highest authority on the subject of optical ac-
tivity and chemical composition, and his writings are always
clear and accurate. In the original the chapter here transla-
ted is well known to chemists. Its appearance in English
and in separate form will no doubt give it a wider circulation
than it could secure as a part of an unwieldy and expensive
book. The translation reads smoothly — something quite un-
usual in translations of chemical books from German into
English. The translator has made certain notes and addi-
tions for the purpose of bringing the matter up to date.

I. R.

A Short History of the Progress of Scientific Chemistry in Our
Own Times. By William A. Tilden, D.Sc, Lond., D.Sc. Dub.,
F.R.S., Fellow of the University of London, Professor of Chemistry
in the Royal College of Science. Ivondon : Longmans, Green & Co.
276 pp.

This is a well-written and interesting book, and one that
will be helpful to students. It is, as the title indicates, a
sho7'i history of the progress of chemistry. It consists of ten
chapters, each of which deals with some important facts of the
subject, and students of chemistry, even those who have a
good knowledge of the history of their science, will find these
chapters profitable reading. The titles are : I. Matter and
Energy ; II. The Chemical Elements : Their Distribution in
Nature, and Recognition by the Chemist; III. Rectification
and Standardization of Atomic Weights ; IV. Numerical Re-
lations among the Atomic Weights : Classification of the
Elements; V. Origin and Development of the Ideas of
Valency and the Linking of Atoms ; VI. The Development
of Synthetical Chemistry ; VII. The Origin of Stereo-Chem-
istry— Constitutional Formulae in Space ; VIII. Electricity
and Chemical Affinity ; IX. Discoveries Relating to the
Eiquefaction of Gases ; X. Summary and Conclusion.

In his preface the author says : "In the following pages I
have endeavored to provide for the student such information
as will enable him to understand clearly how the system of
chemistry, as it now is, arose out of the previous order of

272 Reviews.

things ; and for the general reader, who is not a systematic
student, but who possesses a slight acquaintance with the
elementary facts of the subject, a survey of the progress of
chemistry as a branch of science during the period covered by
the lives of those chemists, a few of whom only remain among
us, who were young when Queen Victoria came to the throne."

And again he says: "Finally, I desire to point out that
this does not profess to be a text- book giving a complete pic-
ture of the state of knowledge and of theory at the moment.
Its object, as already stated, is to show by what principal
roads we have arrived at the present position, in regard to
questions of general and fundamental importance."

The book is cordially recommended to chemists, old and
young. I. R.

The Kinetic Theory of Gases. By O. E. Meyer. Translated from
the second revised edition by ROBERT E. Baynes. London and New
York : IvOngmans, Green & Co. 1899. 472 pp.

The first edition of this book appeared in 1877 and was soon
exhausted. The preparation of a revised edition was, how-
ever, postponed from time to time ; and it was not published
until a year ago. English readers are to be congratulated on
the fact that the publishers secured the services as translator
of Mr. Baynes, of Christ Church, Oxford. The translation is
in every case accurate, fluent, and lucid, and the added notes
are always valuable. The publishers have given us a book
of convenient size and with excellent paper and type, so that
it is a pleasure to read it.

The author divides his subject into two sections, relegating
the more mathematical portions — the complicated formulae
and the manifold discussions — to " Mathematical Appendices"
at the end of the book. These occupy over ]oo pages of
rather fine type and give, on the whole, a fair and ample dis-
cussion of the intricate questions which have excited so much
interest among mathematicians and physicists. It is true that
one does not feel, while reading these sections, the presence
and strength of an original mind grappling with the difficul-
ties, as one does in the two recent text-books on the kinetic
theory of gases by Watson and by Burbury ; but, in spite of
this, the reader is given sufiicient information to make all the
later critical papers by Rayleigh, Boltzmann, and Planck in-
teresting and intelligible.

The portion of the present book, however, which is the most
valuable and which will be more widely read is included in the
first 350 pages. This is divided into three parts : Molecular
Motion and Its Energy ; The Molecular Free Paths and the
Phenomena Conditioned by Them ; On the Direct Properties

Reviews. 273

of Molecules. There are ten chapters : Foundations of the
Hypothesis ; Pressure of Gases ; Maxwell's I^aw ; Ideal and
Actual Gases; Molecularand Atomic Energy ; Molecular Free
Paths; Viscosity of Gases; Diffusion of Gases; Conduction of
Heat; On the Direct Properties of Molecules. Each of these
subjects is treated largely from an historical standpoint and in
such a direct non-mathematical manner that it is delightful
reading. The presentation of the various questions is of such
a nature as to make them easily understood by all, even by
those who may have had no previous knowledge of the sub-
ject. The mathematical formulae on the kinetic theory are
deduced ; the experimental determinations are described, full
references being given ; and discrepancies between theory and
observation are critically discussed. One cannot speak too
highly of this portion of the book. At times, naturally, ex-
ception may be taken to the use or definition of a word, or to
the importance given certain hypotheses , but such criticisms
do not deserve recording. The book is such a storehouse of
observations, theoretical discussions, and experimental for-
mulae, that it is invaluable for reference. The arrangement
of the subject-matter is clear and logical, and the index —
which we owe to Mr. Baynes — is full and accurate.

J. S. Ames.

The Compendious Manuai< oe Qualitative Chemical Analysis
OF C. W. Eliot and F. H. Storer, as revised by W. R. Nichols.
Nineteenth edition. Newly revised by W. B. Lindsay, Professor of
General and Analytical Chemistry in Dickinson College, and F. H.
Storer, Professor of Agricultural Chemistry in Harvard Univer-
sity. New York : D. Van Nostrand Co. 1899. 202 pp.

Among the multitude of works upon qualitative chemical
analysis it is rare indeed to find a manual which has reached
its nineteenth edition, and this fact alone would seem to render
comment upon the merits of this work almost superfluous. It
has proved itself to be, in many hands, a reliable guide alike
for the general student, to whom it presents an excellent ex-
ample of scientific methods of study, and for the professional
student, who, within its scope, derives from it an excellent
training in the manipulation, reasoning, and capacity for ob-
servation, which are essential for the successful analyst. The
passage from this manual to those of wider scope is easy and
natural for the student who has conscientiously followed its
teachings.

The present edition has been rewritten and revised, although
the changes are those of details, and do not alter the general
character of the work. A notable change is that in the
scheme for the separation of the members of the arsenic
group, the fusion of the mixed sulphides with sodium car-

274 Reviews.

bonate and nitrate having been replaced by the separation by-
means of hydrochloric acid and the use of the generator.
Some of the material has been rearranged, many subheadings
have been introduced, and a great many additional and help-
ful comments and suggestions have been scattered through
the text. Since much of the material of this character, new
and old, has been printed in type smaller than that of the
main body of the text, the size of the volume is not iacreased.
It is difficult to understand why, in the revision of this
manual, the teaspoon has been retained as the standard of
measure throughout the work. The graduated cylinder is as
common a laboratory utensil as the beaker or test-tube, and
the expenditure of time or thought in acquiring a concrete
notion of the volume of 5 cc, which is stated in a foot-note to
be the equivalent of the teaspoonful, is surely not serious.
To find the use of a " teaspoonful of strong nitric acid" pre-
scribed on one of its pages is disturbing in a work which has
been prepared with such an evident and careful purpose to
present the subject from a scientific standpoint.

H. p. Talbot.

Descriptive Generai, Chemistry. A Text-Book for Short Course.
By S. E. Tillman, Professor of Chemistry, Mineralogy, and
Geology, United States Military Academy. Second edition. New
York : John Wiley & Sons. 8vo. 429 pp. |3-oo, net.

In the preface to this new edition of the text-book in use at
West Point, the author says that the time which can be
allotted to the study of chemistry at that institution is very
short, and the belief of the instructors has been "that the
laboratory method alone, or mainly, in so short a course, could
not be made of as much value to the pupils as the method
making the acquisition of knowledge the essential feature ;
and that the best results could be reached through careful
study of the proper text, well-conducted recitations accom-
panied by experimental and explanatory lectures. While ac-
cepting the general correctness of this conclusion, the author
would add a small amount of well-selected laboratory prac-
tice."

Of course, if the time allotted to the study of chemistry is
insufficient, the instructor must modify his instruction to fit
the circumstances, but Professor Tillman, after speaking of
the care given to the selection of the information in the book,
continues: " The chemical knowledge most requisite to the
average professional soldier differs but little from that essen-
tial to other educated men."

At first sight one might infer that in the author's opinion a
similar system of instruction would be in place in colleges, in-
stead of the prevailing laboratory system. Few teachers

Reviews. 275

would accept such a conclusion, nor indeed is it probable that
the author means more than to suggest that the text-book
found best for West Point would be equally valuable in col-
leges. This may be doubted. With time and facilities for
laboratory work, text-books which constantly direct the atten-
tion of the student to experimental verification of the state-
ments given will be preferred by most teachers.

For the students, for whose use it isprimaril}^ intended, the
book is good. A more careful revision of the text of the new
edition in the light of modern chemical knowledge would
have been an improvement. For example, the statements
that " ammonia is primarily organic in its origin," that " all
hydrocarbons are primarily derived from the organic king-
dom" cannot stand without ample qualification in view of
what we know of the formation of nitrides and carbides at
high temperatures, and of the action of water on these sub-
stances. E. R.

The Arithmetic of Chemistry. Being a simple treatment of the
subject of chemical calculations. By John Waddeli<, Ph.D. New
York : Macmillan Co. 136 pp. 90 cents.

This little book will be helpful to those college students
who find difiiculty in making chemical calculations, and will
also be of service to teachers, showing them how to explain a
subject, like the measurement of gases, in a clear way.
Several useful tables and a number of problems taken from
English and American university examination papers add to
the value of the book. E. R.

ExPERIMENTELLE ElNFtJHRUNG IN DIE UnORGANISCHE ChEMIE.
Von Heinrich Biltz. Leipzig : Veit & Co. 1900.

In this little laboratory manual Professor Biltz has added to
the usual simple reactions of inorganic compounds a number
which are based on the current theory of aqueous solutions.
The book is clear and modern. E. R.

Qualitative Analyse Unorganischer Substanzen. Von Heinrich
Biltz. Leipzig ; Veit & Co. 1900.

This, too, is a small laboratory manual. The analytical
methods recommended are the best and newest. E. R.

Les Parfums Artificiels. Par Eugf;ne Charabot, Chimiste In-
dustrial, Professeur d' Analyse chimique a I'lnstitut Commercial de
Paris. Paris : J. B. Baillier et Fils. 1900. 296 pp.

There have been rapid advances in the field of the chemis-
try of perfumes during the past few years, and it will there-
fore be of interest to chemists to read this book, which gives
a brief and clear account of the principal discoveries of im-
portance in the field. The titles of the chapters are : I. Nitro

276 Reviews.

Compounds; II. Alcohols and Ethers; III. Phenols and
Ethers of Phenols ; IV. Aldehydes ; V. Ketones ; VI.
Glides. The many varieties of artificial musk are treated of
in Chapter I. There appears to be a great demand for this
perfume, though why, it would be hard to say. There are to
be sure some odors to which it is to be preferred, but not many.

The author says : "The synthetical perfumes which, from
the point of view of their applications, are most interesting are
te7'pineol^ vanillme, piperonal or heliotropine, ionone or artificial
violet, and artificial viusky Terpineol is made by the dehy-
dration of terpenes. It was put upon the market in 1889 and
is now very extensively used for perfuming soaps. It also
enters into the composition of a large number of bouquets,
especially syringa and lilac. The story of ionone or artificial
violet is the most interesting in the book, from the scientific
as well as from the commercial point of view. According to
the author : " The discovery of ionone, which is now exten-
sively employed, has not worked any injury to the cultivation
of the violet in the department of the Maritime Alps. In
fact, this cultivation has extended since 1893 without leading
to a lowering of the price of the flower."

It is interesting to note that piperonal or heliotropine.
which in 1879 cost 3790 francs a kilogram, cost only 37.5
francs a kilogram in 1899. i. r.

Vol. XXIII. April, 1900. No. 4.

AMERICAN

Chemical Journal

THE EIvECTRICAIv CONDUCTIVITY OF EIQUID
AMMONIA SOLUTIONS.

By EJdward C. Franklin and Charles A. Kraus.

In a recent paper' the authors pointed out some analogies
between the properties of liquid ammonia and those of water,
showing, among other things, that of all known electrolytic
solvents ammonia most closely approaches water in its power
of forming solutions which conduct the electric current. The
interest which attaches to the study of liquids with such
high conducting power has led the authors to undertake more
careful measurements of the conductivity of ammonia solu-
tions than have yet been attempted.

None of the measurements hitherto made on ammonia solu-
tions" can be used for more than a qualitative comparison
with aqueous and other solutions ; and from somewhat ex-
tended experiments on the part of the authors it became evi-
dent that reliable quantitative results were not to be obtained
with any of the simple forms of apparatus used in previous in-
vestigations. It was therefore found necessary to devise a
form of apparatus by means of which the solvent could be
purified and isolated for a considerable length of time. It was
also essential to arrange the apparatus so that both solvent
and solute could be added safely and conveniently. At the

1 This Journal, 21, 8 (1899).

2 Cady : J. phys. Chem., 1, 707 (1897) ; and Goodwin and Thompson : Phys. Rev.,
8, 38 (1899)-

278 Franklin and Kraus.

same time it was necessary to be able to remove known por-
tions of the solution from the resistance vessel, and to supply
the place of the removed solution by fresh solvent. Finally
the escape of large quantities of gaseous ammonia into the
air of the laboratory had to be avoided.

The following is a description of the form of apparatus
which the authors found to be well adapted to meet the above
enumerated requirements.

Description of the Apparatus.

The steel cylinder A, containing the liquid ammonia which
is to be purified, is provided with a valve of a pattern which
permits the easy regulation of the flow of gas. The metal de-
livery tube of the valve was connected with the glass tube B
by means of a piece of rubber tubing, which, to withstand the
pressure, was first tightly tied and then wrapped with tape.

On opening the valve the gas passes from the cylinder A
through the glass tube B, which carries an asbestos filter, C,
into the condensing spiral D, whence it runs as a liquid into the
receptacle E. To the tube B is attached a pressure gauge F,
for the purpose of assisting the manipulator to regulate more
easily the flow of gas. The asbestos filter is a glass tube
filled with carefully dried asbestos. The constrictions are
for the purpose of preventing the packing of the asbestos into
one end of the tube when the pressure from A is turned on.
The asbestos used was the serpentine variety which, unless
freed of its water of crystallization by long heating over the
blast-lamp, continued indefinitely to give up sufficient mois-
ture to the ammonia to affect materially its conductivity.

The filter is an important part of the purifying apparatus,
its object being to retain minute particles of solid material
which may be carried over by the stream of gas. That for-
eign matter was carried over from the stock cylinder is proved
by the following observations : Other conditions being the
same it was not possible without the filter to obtain a distillate
with anything like the high resistance of the pure solvent.
With fresh sodium in the cylinder A, a sufficient quantity of
the metal was carried over to give the ammonia in the recep-
tacle E, a decided blue color, and to reduce the resistance in

28o Franklin and Kraus.

this cell to less than a hundredth of its value under other con-
ditions. •

The purity of the solvent was determined by making meas-
urements of its conductivity, for which purpose a pair of elec-
trodes, GG^ was sealed into the receiver E. The electrodes
are in metallic connection with the exterior and the measur-
ing apparatus through the glass tubes HH, sealed around the
connecting wires and filled with mercury. The receptacle
and spiral were kept cold by surrounding them with a bath of
liquid ammonia contained in the vacuum-jacketed vessel /.
During the investigations this vessel developed a crack, and,
the necessary tubing not being at hand to replace it, an air
jacket was substituted in its stead with satisfactory results.
A little alcohol between the walls of the air jacket served to
absorb the moisture which otherwise would have frozen on
the walls and obscured the view of the receptacle and its con-
tents. The opening in the lower end of the vessel / is closed
by a rubber stopper through which passes the delivery tube K
from the receiver E. Care had to be taken to have this stop-
per fit well, as otherwise a little pressure is liable to force out
liquid ammonia, which almost inevitably breaks the jacket.
The upper end of the vessel, /, is likewise closed with a rub-
ber stopper, which is fitted with holes, first, for the tube L
through which ammonia is drawn from the stock cylinder M
into the bath /; second, for the escape tube iV, for carrying
off the gas ; and third, for the tube O, through which the
bath may be emptied of its contents by simply closing the
stop-cock A^. Besides these, the tubes HH, making connec-
tion with the electrodes, also pass through this stopper. The
tubes B, L, N, and O are fitted gas-tight into the stopper,
while for the tubes HH large holes were made so that the
stopper might be forced tightly into place without danger of
breaking these tubes loose from their connections with the re-
ceiver E. When all the tubes were in place, the stopper was
tied firmly to the vessel /, and the space around the tubes HH
was filled up with laboratory wax.

The condensation of the gas in the spiral D and the re-
ceiver E is produced at the expense of an equivalent quantity
of liquid ammonia which evaporates from the bath /. The

Electrical Conductivity of Liquid Ammonia Solutions. 281

gas escapes through the tube N and is thence conducted into
a carbo}^ containing water where it is recovered as aqua am-
monia.

When a sufl&cient quantity of liquid has been collected in
the receivei E, the stop-cock P is opened and the ammonia
runs into the conductivity vessel Q. This vessel is provided
with a pair of electrodes, 5^, which is connected with the
exterior and the measuring apparatus by means of glass tubes
filled with mercur}^ in the same manner as are the electrodes
GG in the upper receptacle. Connections for the electrodes
6"^' are not shown in the figure. Five fine glass pointers, T^
were sealed into the resistance cell O, point upwards. The
volume of the cell up to these different points was determined
by filling with water at 25° until the respective points were
just breaking the surface, and caculating the observed vol-
umes to the volume at the boiling-point of ammonia. Sealed
into the cell Q at Q' and reaching to the bottom, is a glass
tube, V, which has capillary dimensions from the point at
which it enters the resistance vessel to its lower end. This
tube is provided with a stop-cock, W, just beyond which con-
nection is made with the tube W . W carries a two-way
stop-cock X. One way leads to the open air through the
soda-lime drying tube X\ while the other, X" , leads to the
vacuum-jacketed tube Y. The purpose of this vessel K will
appear below.

The tube KK' leading from the receiver E to the vessel Q
reaches well through the neck of the latter into which it is
fitted by means of a rubber stopper. A short distance above
this stopper the tube K is enlarged and the tube from above is
sealed in so that it projects about i centimeter within the en-
largement, as shown in the figure. In the side of the en-
largement, and with an upward slant, is sealed a tube, Z,
through which the solute is introduced into the conductivity
cell.

The solute is weighed out in a small platinum spoon, y,
enclosed in a weighing tube as shown in Figure 2. In order
to introduce the solute, the spoon is removed from the weigh-
ing tube and placed in position in the tube Z. A half turn
on the axis of the spoon holder empties the contents into the

282 Franklin and Ki'aics.

cell Q. Any portions of the solute which may remain cling-
ing to the spoon or to the side of the tube are washed down
by the ammonia drawn from the receiver E.

Just below the stopper, through which K' enters the neck
of the resistance receptacle, is sealed a tube provided with a
stop-cock, U, and leading to the vessel Y. This attachment
enables the operator to wash out the neck of the vessel Q as
described below.

To the neck of the vessel Q is sealed a second tube carry-
ing a two-way stop-cock, a, one branch of which, a', leads
through the phosphorus pentoxide drying tube c to the pres-
sure reservoir containing dry air free from carbon dioxide.
The other branch, a" , leads through a soda-lime drying-tube,
d, to a two-way stop-cock, e, one branch, <?', of which opens to
the air, while the other, ^", leads to a collecting bottle con-
taining water.

Preparatory to making a series of measurements, the resis-
ance vessel Q must be well washed out and supplied with pure
solvent from the receptacle E. To accomplish this, ammonia
is drawn down by opening the stop-cock /'until the electrodes
^5 are well covered, the stop-cocks a and ^ having previously
been set to open the way through «" and e^\ and the stop-
cocks Wand 6^" having been closed. By this arrangement of
the stop-cocks the ammonia vapor escapes through e" into the
absorption bottle. The stop-cocks JV and X, through X",
are then opened, and a is set to close a" and open a'. The
pressure from the air reservoir on the surface of the liquid
forces this latter out through the tube V into the vessel V,
thus emptying Q. After emptying the resistance cell the stop-
cocks are turned back to their original positions and a fresh
quantity of ammonia is drawn down into the cell. This oper-
ation is repeated until tests of the resistance in the cell Q
show that all soluble material has been removed. Wis then
opened, and with ^Fand a closed, the liquid is run down into
the lower vessel until it fills the cell completely and runs over
into F through U. The stopper is then removed from Zand
a quantity of ammonia is allowed to blow out through this
portion of the apparatus. The ammonia is then run out
through Fin the manner described above. In this way the

Electrical Conductivity of Liquid Ammonia Solutions. 283

resistance cell is thoroughly washed. The next lot of ammo-
nia run down is tested, and in case its resistance indicates suf-
ficient washing of the cell Q the operator proceeds to the ad-
dition of the solute.

The previously weighed solute is introduced in the manner
described above, and, with the stop-cocks properly set, am-
monia is let down into the resistance cell until the first pointer
is slightly more than covered. The stop-cock e is then set to
open the way through e' to the outside air ; Wis opened, and
X is set to open the way through X" . With this arrangement
of the stop-cocks, the back pressure from the vessel K forces
ammonia vapor through the liquid in the resistance cell.
This current of ammonia gas, warmed by its passage through
X" , W, and V, evaporates ammonia from the resistance cell
and at the same time thoroughly mixes the solution. After
passing the vapor for a few moments, X" is closed and X' is
opened. Both the tubes V and <f' being, with this arrange-
ment of the stop-cocks, open to the air, the liquid in Q and V
comes into pressure equilibrium. If, after this operation, the
tip of the glass pointer is not visible just breaking through
the surface of the solution, the above-described operation is
repeated until the point just touches the surface. The resis-
tance is then measured. The solution is then diluted, stirred,
adjusted to the next pointer, and the resistance again read.
This operation is repeated until the last point is reached, after
which the solution is forced out through the tube V in the
manner described above, until the lowest point is reached,
when the stop-cock W is closed. This leaves a known quan-
tity of solute in the resistance cell. More solvent is then
added, the volume adjusted to the second pointer, and the re-
sistance again measured. In this manner measurements may
be made on solutions carried to any desired degree of dilu-
tion.

T/ie Co7istant Temperature Bath. — In order to maintain the
resistance vessel Q at a constant temperature it is immersed
in a bath of liquid ammonia contained in the Dewar tube i?.
To overcome the considerable superheating which ammonia
exhibits in glass vessels, it was at first attempted to boil the
liquid in the bath by means of a spiral of platinum wire

284 Franklin and Kraus.

heated by a current of electricity. This plan was soon aban-
doned, however, for the much simpler and quite as efficient
method of placing blackened platinum tetrahedra in the bot-
tom of the bath and warming them by the radiations from an
ordinary incandescent lamp. No errors from changes in the
temperature of the bath could be observed.

The mouth of the vessel R is fitted with a rubber stopper
which supports the resistance cell Q, and in which provision
is made for the mercury connecting tubes, and for the tubes/
and g for introducing the liquid and carrying off the gas, re-
spectively. The mercury connecting tubes are not shown in
the figure. Liquid ammonia is introduced into the bath R by
opening the stop-cock L through/ and then opening the valve
on the steel cylinder M.

Recovery of Liquid Ammonia from Receptacle Y. — A glass
tube carrying a stop-cock, A, is sealed to the tube L, through
which ammonia is drawn from the stock cylinder to the baths
/ and R. If this stop-cock is opened and an aspirator attached
to the exit tube A^, then liquid from without may be drawn
into the bath /by connecting a tube A' to A, and immersing
the end of the former in the liquid. Thus, ammonia which
has been used in the resistance cell can be drawn from the
vessel yinto the bath /and utilized for cooling the receiver.
To Empty the Condensing Bath, I. — After considerable
liquid has been evaporated from the bath /, the residue be-
comes so impure that the frothing of the liquid in boiling in-
terferes with the distillation. By opening the stop-cock i on
the tube (9, and closing the stop-cock on the exit tube A^, the
pressure of the boiling ammonia forces out the liquid through
O, thus emptying the bath of its contents. This was always
necessary at the end of a series of experiments.

The apparatus is somewhat complicated, but after a little
practice on the part of the operators, measurements can be
carried out easily and with a fair degree of accuracy. With
everything in order, from two to three series of measurements
can be made in half a day.

The Solvent. — The ammonia used in these experiments was
the " Liquid Anhydrous Ammonia" of commerce, such as is

Electrical Conductivity of Liquid Ammonia Solutions. 285

used for refrigerating purposes. An earlier plan, of distilling
the ammonia once or twice before its final distillation from
the cylinder A of the purifj'ing apparatus, was later aban-
doned for the simpler and entirely satisfactory plan of drawing
the liquid from the stock cylinder directly into the smaller
cylinder, into which latter a quantity of metallic sodium had
previously been introduced. The sodium dissolves in the am-
monia, and any water present in solutionis at once acted upon
by the metal with the formation of insoluble sodium hj'-drox-
ide. The sodium not used up by the water present reacts
slowly with the ammonia to form sodamide and hydrogen.
The sodamide is somewhat soluble and is an efficient drying
agent. The ammonia distilled from sodamide into the recep-
tacle E was very pure, as was shown by tests of its resistance,
which, after the introduction of a good asbestos filter in the
train, was found to be uniformly very high. In fact, the re-
sistance was so great that it was not possible to measure it,
even approximately, with the measuring apparatus in its pres-
ent form, and, moreover, the high resistance did not diminish
when the liquid remained in the cell for some hours, proving
that, contrary' to the behavior of water, liquid ammonia is
without appreciable action on glass. Attempts to obtain the
purest possible ammonia in the receiver E were not made,
partly for the reason that the means were not at hand for
measuring very high resistances, but principally for the reason
that other sources of impurity were present which could not
be overcome in the present experiments.

While ammonia of a specific conductivity below o.oi X io~*
was easily obtained in the receiver, it was not possible to pro-
duce a liquid which, after being run into the resistance cell Q,
showed a specific conductivity lower than about o.io X io~*.'

Certainly one of the sources of impurity, to which reference
has just been made, is moisture which enters the stop-cock P.
Water lowers the resistance of liquid ammonia. As a result
of the contact of cold ammonia with the stop-cock, moisture
condenses on the latter, and small, but sufl&cient, quantities
w^ork in around it to reduce the resistance of the solvent very

lOoodwin and Thompson [Phys. Rev., 8, 47 (1S99)] give 1.6 X io~* as the mean
specific conductivity of liquid ammonia at temperatures between — 30° and — 12°, a
value very much greater than the minimum obtained in these experiments.

286 Franklin and Kraus.

materially. Nor is this defect easily remedied. An ordinary
glass stop- cock cannot be ground to be absolutely tight with-
out the use of lubricant, which must, of course, be omitted from
a cock used for the present purpose. After experimenting
with a number of different styles of stop-cocks, a mercury- seal
cock was finally used for the measurements recorded in this
paper. The niercurj^ however, was left out and the empty
spaces on either end of the key opened into the air through
pieces of small rubber tubing of considerable length. The am-
monia which leaked through the stop-cock was thus allowed to
escape, while the deposition of moisture was confined to the ex-
terior of the stop-cock. Even with this stop-cock, which gave
much better results than any other form used, the specific con-
ductivity of the solvent in the resistance cell Q could not be
reduced much below o.io X Io~^ The specific conductivity
varied between o.io X io~* and 0.15 X io~^, or even more, and
could not be accurately controlled.

Solutes. — With the exception of sodamide, all the salts and
other substances used in these experiments were carefully
purified and thoroughly dried before being used. The con-
centration of the sodamide solutions for which measurements
are given were arrived at by calculation from a weighed
quantity of sodium added to the solvent.

Measuring Apparatus, Constants, and Units. — The bridge
and telephone method of Kohlrausch was used in making the
measurements of conductivity recorded in this paper. With
the highest dilutions the resistance reached 20,000 ohms. At
this resistance the telephone minimum became so poor that it
was not practicable with the present form of the apparatus to
carry the dilutions higher. Besides the errors introduced by
the variable conductivity of the solvent, some of the inaccu-
racies in the measurements at high dilutions are to be attrib-
uted to the difficulty of accurately setting the bridge at such
high resistances. Another source of error which is easily in-
troduced is insufficient stirring. The solutions were usually
stirred until no further change could be detected in the con-
ductivitv, but doubtless some errors are due to this cause.

Electrical Conductivity of Liquid Ammonia Solutions. 287

The units recently introduced by Kohlrausch' were used in
calculating the values given below.

The resistance capacity of the cell, determined by means of
a fiftieth-normal solution of potassium chloride of specific con-
ductivity 0.002397° at 18", was 0.07344.

The volumes of the conductivity cell at the boiling-point of
ammonia for the five points was 45.70 cc. , 67.6700., 94.75 cc,
117.09 cc, and 141. 16 cc, respectively. The volume to the
first point plus the volume of the stirring tube F was 46.62 cc.

The atomic weights recently recommended by the commit-
tee of the German Chemical Society, which are calculated on
the basis of oxygen = 16, were used.

The correction made for the conductivity of the solvent was
0.13 X io~*, which was approximately the mean conductivity
of the solvent as measured in the resistance cell Q, after thor-
oughly washing out the latter. The correction for the high-
est dilutions amounts to about 4 per cent.

Numerical Results. — In the following tables are given the
results of measurements on twenty-five different substances.
Besides these substances measurements were also made on
potassium iodide, sodium nitrate, ammonium bromide, and
silver nitrate, but because of the uncertain value of the resis-
tance capacity of the cell at the time of making these meas-
urements, they are not included in the tables below.

The dilutions, expressed in liters per gram molecule, are
denoted by v, the molecular conductivities by fx^, which cor-
respond respectively to (pio~^ and /^ in Kohlrausch's' notation.

1 Kohlrausch uud Holborn : Das I,eitverta6gen der Electrolyte, p. i (1899); Kohl-
rausch, Holborn, und Diesselhorst : Wied. Ann., 64, 417 (1898).

2 Kohlrausch : Loc. cit.
s Ibid.

288 Franklin and Kraus.

Table I — Potassium Bromide.

301.9 210.6 7093.0 324.6

447.0 228.3 8553.0 323.9

625.9 242.3 12410.0 329.7

773-4 251.7 17380.0 333.:

932.6 259.5 21480.0 336.1

1354.0 272.9 25900.0 337-0

1895.0 286.8 37590-0 338-7

2343.0 293.7 52640.0 339.6

2824.0 299.8 65040.0 340.2

4099.0 308.5 78430.0 340.4

5740.0 317.6

Table II — Potassium, Nitrate.

324.0 192.7 7614.0 314

479.9 210. 1 9181.O 318

671.9 226.0 13330.0 322

830.2 236.7 18660.0 327

looi.o 245.0 23060.0 330

1453.0 261.7 27800.0 331

2082.0 274.9 40360.0 333

2514.0 282.9 56510.0 337

3032.0 289.3 69820.0 338

4401.0 301.4 84200.0 337

6162.0 309.9

Table III — Potassium Metanitrobenzenesulphonate.

V.

}Xy.

V.

)X^.

144.8

135-5

4522.0

242.8

214.5

147.2

6332.0

250.9

37I-I

166.8

9190.0

257-3

538.7

179.8

12870.0

263.0

754-3

192.5

18680.0

268.6

1095.0

204.1

26150.0

271.0

1533-0

215-5

37960.0

276.1

2225.0

225.8

53160.0

281.2

3116.0

234-5

Electrical Conductivity of Liquid Ammonia Solutions. 289

Table IV — Sodium. Bromide.

V.

}^v

V.

f^v

287.0

200.0

6744.0

287.7

425.0

214.5

8132.0

289.9

595-1

227.4

II8I0.0

292.0

735-4

234-7

16530.0

296.0

886.8

240.2

20420.0

297.9

1287.0

251-7

24630.0

298.2

1802.0

262.5

35750.0

298.1

2227.0

266.8

50050.0

299.8

2686.0

271. 1

61840.0

303-0

3898.0

277.6

74580.0

302.1

5458.0

283.8

Table V — Sodium. Bromaie.

V. IXy. V. }Xy.

342.3 179.4 1535-0 229.5

506.9 193-4 2150.0 238.6

709.8 205.1 2656.0 244.0

877.0 212.5 3203.0 247.8

1058.0 218.7 4648.0 255-.2

Table VI — Sodium Bromate.

V.

}^v

V.

Mv

323-4

177.6

7600.0

263.7

479-0

I9I-5

9164.0

265.9

670.7

210.8

13300.0

269.1

828.7

211. 0

18620.0

271. 1

999-3

217. 1

23020.0

273-4

1451.0

227.9

27760.0

273-9

2031.0

238.0

40280.0

275-i

2509.0

243-1

56400.0

275.8

3026.0

247-5

69690.0

276.7

4392.0

253-9

84040.0

275-7

6150.0

260.9

290 Franklin and Kraus.

Table VII — Ammonium Chloride.

298.9 159.0 7023.0 280.5

442.6 176.3 8468.0 285.6

619.8 191. 2 12290.0 292.0

765.8 200.3 17210.0 296.2

923.4 208.7 21270.0 298.8
1340.0 224.4 25650.0 301-1
1877.0 238.9 37220.0 303.7
2319.0 246.5 52120.0 303.9
2796.0 253.1 64400.0 301.4
4059.0 264.7 77660.0 304-4
5684.0 274.2

Table VIII — Ammonium Nitrate.

V. Mv ^- Mv

105. 1 169.7 6057.0 286.6

155.8 183.8 7385-0 288.9
218. 1 195.3 9024.0 291.4

269.5 203.1 13100.0 294.2

324.9 210.4 18340.0 296.3

471.6 222.4 22660.0 296.6

660.4 233.7 27330.0 297.0
816.0 240.5 39670.0 297.1

984.0 245.6 55540.0 295.5
1428.0 256.9 68640.0 298.5
2000.0 266.8 82760.0 298.7
2471.0 271. I 120100.0 294.3
2980.0 276.1 168200.0 299.4
4325.0 281.4

Table IX— Silver Iodide.

V. Mv

212. 1 71.06
314. 1 83.50
439.8 96.29

543.5 100.9

655-4 107-9

951.3 122.7

1332.0 137-1

1646.0 146.5

1985.0 155.5

2881.0 175-2

4034.0 188.2

V.

Mv

4984.0

198. 1

601 1. 0

205.9

8724.0

221. 1

I22IO.O

233-9

I5IOO.O

242.1

18200.0

247-5

26420.0

256.3

36990.0

265.2

45710.0

270.6

55120.0

274.0

80000.0

276.0

Electrical Conductivity of Liquid Ammonia Solutions. 291

Table X — Silver Cyanide.

V.

f^v

V.

Ply

44.77

20.21

556.6

21.52

66.30

20.53

779-4

21.65

92.84

20.78

1131.0

21.54

134.84

20.88

1584.0

21.65

188.7

21.17

2299.0

21.45

273.8

21.31

3219.0

21.50

383-4

20.64

Table XI — Mercuric Cyanide.

V.

IXy.

V.

}^v

24.17

1.20

6.92

1-44

35.79

1. 18

10.25

1.35

50.12

1. 17

14-35

1.30

72.75

1. 16

20.83

1.25

IOI.9

1. 16

29.17

1.23

147.9

1. 16

42.34

1.23

207.1

1. 17

59.28

1.22

86.04

1.20

120.5

1.20

174.9

1. 19

244.9

1. 19

Table XII — Metadinitrobenzene.

V.

l^v

V.

^v

354.5

131. 6

5590.0

217.0

525.0

144. 1

8114.0

221.3

735.0

155-7

1 1360.0

(225.8)

1067.0

168.6

14040.0

232.5

1494.0

178.7

20380.0

234-3

2226.0

190.4

29570.0

236.0

3231.0

203.7

292 Franklin and Kraus.

Table XIII — Strontium Nitrate.

286.2 I45-0 8108.0 299.0

423.9 160.2 11770.0 321.5

593-3 173-7 16480.0 344.4

733.2 182.6 20360.0 359.3

884.1 190.6 24550.0 371. 1

1283.0 207.0 35640.0 403.1.

1797.0 221.9 49900.0 431-4

2220.0 232.1 61660.0 449-0

2677.0 240.8 74350.0 466.2

3886.0 258.1 107900.0 491-9

5441.0 275.8 151100.0 514.2

6724.0 288.4

Table XIV — Sodamide.

27.49 4.923 169.2 15.69

38.49 6.013 236.9 19.53

47.56 6.896 343.8 23.84

57-35 7-739 481.4 28.17

83-23 9-698 698.7 32.35

116. 5 12.09 978.6 35.52

Table XV — Acetamide.

V. I^v ^- ^v

5.020 0.2841 30.71 0.4507

9.434 0.3134 43-00 0.4850

10.41 0.3413 62.41 0.5266

15. II 0.3768 87.39 0.5670

21.15 0.4130

Table XVI — Benzenesulphonamide.

V. Mv

42.00 18.03

62.19 21.70

87.08 24.41

126.4 28.45

177.0 32.65

256.9 38.01

359-7 43-62

522.0 51.05

V.

f^v

731.0

58-43

I06I.0

67.25

1485.0

76.72

2156.0

87.86

3019.0

106.9

4382.0

122.4

6136.0

137.2

8916.0

I5I-9

Electrical Conductivity of Liquid Ammonia Solutions. 293
Table X VII — Orthomethoxybenzenesulphonamide.

V.

Mv

V.

Mv

IOI.2

14-13

2811.0

59-09

141. 8

16.34

3937-0

67.67

175-2

17.92

4864.0

73-16

211. 2

19.44

5866.0

79-36

306.6

22.88

8514.0

90.24

429-3

26.53

11920.0

lOI.I

530.4

29.10

14730.0

108.3

639.6

31.61

17760.0

II5-7

928.3

37-33

25780.0

127.6

1300.0

42.88

36100.0

139-7

1606.0

46.79

44610.0

147.7

1937-0

51-05

Table X VIII — Meta ynethoxy beri zenes ulphonam ide .

V ,

^v

V.

}^v

57-96

23-92

1809.0

91.03

85.82

27-85

^h2>7>-^

102.2

148.5

34-71

3677.0

II4.9

215-5

40.81

5149-0

124.5

301.7

45-93

7473-0

140.9

438.0

53-57

10460.0

153-5

613-3

60.91

15190.0

165-9

890.2

70.20

26280.0

183.2

1247.0

79.60

Ta ble XIX — Pa ra methoxyben zenesulphonamide.

V,

h^v

V.

l-fv

55-50

11.27

1326.0

47-16

77-70

13-23

1924.0

54-93

122.8

15-51

2694.0

63.20

157-9

17-96

3910.0

73-55

229.2

21.05

5475-0

83-71

320.9

25-13

7947-0

96.01

465.8

30.01

11130.0

109.4

652.2

34-74

16150.0

126. 1

946.7

40.92

22620.0

140.2

294 Franklin and Kraus.

Table XX — Metanitrobenzenesidphonamide .

85.68 89.54 2164.0 184.6

126.9 99.70 3031-0 193-3

177.6 109. 1 4399.0 200.9

257.9 119. 7 6159.0 207.3

361.0 130.4 8940.0 213.9

524.0 142.0 12520.0 219.6

733-8 153-3 18170.0 222.7

1065.0 164.3 25440.0 224.1

1491.0 174-8 36930.0 227.1

Table XXI — Benzoic Sulphinide.

V.

//„.

V,

lAy.

118. 1

85.98

2983.0

167-5

174.8

94-45

4177-0

176.3

244.8

101.7

6062.0

184.0

355-3

110.5

8488.0

191. 8

497.6

119. 0

12320.0

196.6

722.1

129.3

17250.0

203.8

lOII.O

139-5

25040.0

207.3

1468.0

149.6

35060.0

211. 4

2055.0

159-2

Table XXII — Trinitrotoluene.

V.

l^v

V.

^v

158.0

164.4.

2427.0

203.1

233-9

170.4

3398.0

208.0

404.8

178.0

4932.0

212.8

587-5

180.4?

10030.0

223.9

822.7

187-5

14040.0

228.1

1194.0

193.2

20380.0

233-8

1672.0

198.6

Electrical Conductivity of Liquid Ammonia Solutions. 295
Table XXIII — Nitromethane .

V.

l^v

V.

l^v

8.99

9.01

646.4

47.95

13-31

10.02

938.2

56.12

18.64

II. 15

1306.0

64.66

27.06

12,76

1907.0

75-24

37-89

14-52

- 2670.0

85.92

55-00

16.89

3876.0

99.68

77.00

19.38

5426.0

114-5

III. 8

22.55

7876.0

131-5

156.5

26.15

I 1030.0

147-3

227.1

30.55

I60IO.O

162.5

318. 1

35.37

22410.0

181. 3

461.6

41-45

Table XXIV-

-Orthonitrophenol.

V.

fAy.

V.

}^v

366.2

82.76

6963.0

190.6

542.3

95-11

8604.0

192.8

759-3

106.6

10380.0

203.9

938.2

114.0

15060.0

213.3

1131.0

120.7

21090.0

222.5

1642.0

135-3

26060.0

226.2

2299.0

148.3

31420.0

230.3

2841.0

157-1

45610.0

234.9

3426.0

164.5

63860.0

240.1

4973-0

178.7

Table XXV-

—Benzaldehyde.

V.

Mv

V,

IXy.

15-53

1-695

133-0

3-385

23.00

1-950

193- 1

3-736

32.20

2.198

270.3

4.058

46.74

2.493

392.4

4-328

65-45

2.770

549-4

4.561

95.00

3.078

Discussion of Results.
Besides the measurements above given, quantitative deter-
minations of the molecular conductivity of potassium iodide,
sodium iodide, ammonium iodide, cuprous iodide, silver bro-
mide, silver nitrate, lead iodide, mercuric iodide, mercuric
chloride, zinc iodide, cupric nitrate, iodine, sulphur, parani-

296 Franklin and Kraus.

trophenol, dinitrophenol, trinitroplienol, vanilline, ethyl for-
mate, ethyl acetate, metallic potassium, and metallic lithium
have also been made, but the results are not given here for
the reason that the measurements were made in an earlier
form of apparatus which did not permit of sufl&cient accuracy
of measurement. Qualitative tests have been made on sev-
eral hundred substances, which show that all soluble salts
and a great variety of organic compounds form conducting
solutions.

Binary Salts. — The limit of molecular conductivity of
binary salts in solution in ammonia at — 38° lies between 270
and 340 Kohlrausch units. This is more than twice the maxi-
mum conductivity of the same salts in water solutions at the
ordinary temperature, and is far above the conductivity of
electrolytes in any other known solvent. At 100°, however,
the limit of molecular conductivity in aqueous solution is
somewhat greater' than the maximum conductivity of the
same salts in solution in ammonia at its boiling-point.

The values for the maximum molecular conductivities of a
number of salts in five of the best electrolytic solvents are
given in the following table, which is made up from data
taken from Dutoit and Friderich,^ and from Carrara,^ together
with values obtained for ammonia solutions by the authors.^

Aceto-

Methyl

' Acetone.

nitrile.

alcohol.

Water.

Ammoni

Nal

140

160

90

121

NaBr

88

122

302

KI

154

98

143

340?

KBr

97

144

340

NHJ

153

105

143

NH.Cl

100

144

304

KNO3

133

338

NH^NO,

114

297

AgN03

160

121

280?

HCl

2.21

133

360

Notwithstanding the fact that for the most part ammonia
solutions conduct electricity with greater facility than do

1 Krannhals : Ztschr. phys. Chem., 5, 250 (1890); and Schaller : Ibid., 35,497
(1898).

2 Bull.Soc. Chim. (3), 19,336 (1898).

» J. Chem. Soc. Abstracts, 72, II, 471 (1897).

Electrical Conductivity of Liquid Ammonia Solutions. 297

water solutions of the same concentration, the solute in am-
monia is dissociated to a much less extent than it is in water.
The accompanying table shows, for nine salts dissolved in
these two solvents, the dilution at which the dissociation
reaches respectivel}^ 50, 75, and 90 per cent.

Solute

Degree of
dissociation.

Water. Clf/9'*

Ammonia. Qf^ "^^

KI

0.50

....

80

0.75

0.4

400

0.90

20.0

2000

KBr

0.50

....

100

0.75

....

800

0.90

20.0

4000

KNO3

0.50

0.5

200

0.75

5-0

1200

0.90

25.0

5000

NaBr

0.50

....

125

0.75

....

500

0.90

32.0

2500

NaNO,

0.50

0.5

. . ■,,

0.75

5-0

800

0.90

33-0

4000

NH.Cl

0.50

....

250

0.75

I.O

1500

0.90

25.0

5000

NH^Br

0.50

75

0.75

....

700

0.90

....

3500

NH.NO,

0.50

....

100

0.75

500

0.90

....

4000

AgN03

0.50

0.6

125

0.75

5-0

350

0.90

40.0

1500

Aqueous solutions of binary salts practically reach their
limit of molecular conductivity at a dilution of 1,000 to 5,000
liters, while ammonia solutions must be carried to a dilution
of 25,000 to 50,000 to come as near the limit. In accordance
with the Thomson-Nernst hypothesis, this behavior of ammo-
nia solutions was to be expected from the low dielectric con-
stant as found by Goodwin and Thompson', and later by Cool-

iPhys. Rev., 8, 38 (1899).

298 Franklin and Kraus.

idge.' The low degree of dissociation is also in accordance
with measurements of the boiling-point elevations of ammonia
solutions of salts." At the concentrations at which these
measurements were made the dissociation is so low that it
would be difi5cult to detect the effect of dissociation on the
rise of the boiling-point of a solvent with such a low constant
of molecular elevation as that of ammonia.

The very high conductivit}' of ammonia solutions seems
hence to be due to the high velocity of migration of the ions
as a result of the low viscosity of the solvent.

Ostwald's law of dilution holds approximately for ammonia
solutions of a number of binary salts, the only solutes which
have so far been tested. The constant diminishes in value
with the dilution but the change is of a very different order
from that which is found in the case of water solutions of the
same salts. The values for the constants for three salts, cal-
culated from the formula

in which the symbols have their usual significance, are given
below for both ammonia and water. The values for the
water solutions are calculated from Kohlrausch's data.^

t 52.30

Ammoniwn Chloride.

NHj.

H2O.

O.I9I9

....

58.00

0.1809

62.89

0.1760

49.68

65.89

0.1662

45.47

68.64

0.1628

38.54

73.81

0.1553

22.86

78.58

0.1536

11-53

81.09

0.1533

5.981

83.25

O.I48I

5.527

87.08

0.1445

3.777

90.20

0.1460

2.506

92.26

0.1568

1.749

93.91

0.1932

1.264

96.05

0.1897

0.8435

1 Wied. Aun., 69, 130 (1899).

2 The Authors : This Journal, 20, 852 (iS
K I,eitfahigkeit der Electrolyte, p. 159.

Electrical Conductivity

' of Liqtiid

Ammonia

Solutio7is.

4L

' Potassium Nitrate.

NHj.

HjO.

57.00

0.2277

12.79

62.12

0.2074

"•55

66.85

0.2006

10.20

70.02

0.1970

9.528

72.48

0.1906

8.754

77-41

0.1826

6.269

81.32

0.1740

4-509

83.66

0.1706

4.006

85-59

0.1677

3-389

89-15

0.1623

2.893

91.66

0.1635

2.332

93-15

0. [664

1.885

94-30

0.1699

1. 710

95.28^

viMp-^'^^-'*''

1-443

Potassiu7n Bromide.

».

NH3.

a.

NH,.

61.76

0.330

90.47

0.210

66.94

0.303

93.12

0.220

71.06

0.279

94-97

0.210

73-81

0.269

96.67

0.222

76.09

0,260

97-79

0.250

80.02

0.237

98.56

0.315

84.10

0.235

98.81

0.321

86.12

0.228

299

Silver Halides. — Measurements of the conductivity of the
halides of silver is a matter of interest in view of the fact that,
because of their resistance to the action of most ordinary sol-
vents,' their conductivities have not been measured.

Silver iodide in solution in ammonia is a good conductor,
but it is not as strongly dissociated as is the nitrate of silver,
a fact which is not unexpected when the behavior of mercuric
chloride and the halides of some other heavy metals in resist-
ing the dissociating action of water is recalled.

Merctiric Chloride. — This salt reacts with liquid ammonia to
form mercuriammonium chloride, but since at the same time
a small quantity of an insoluble compound was formed, quan-
titative measurements of the conductivity of mercuriammo-
nium solutions have not yet been made.

1 According to St. v. Lasczynski and St. v. Gorski [Ztschr. Electrochem., 4, 290
(i897)]i s pyridine solution of silver iodide is a non-conductor of electricity.

300 Franklin and Kraus.

The results of a brief investigation of the action of liquid
ammonia on mercuric chloride may be given here. When
mercuric chloride is sealed up in a tube with liquid ammonia,
a heavy liquid of the composition represented by the formula

HgCl,.2NH,.ioNH3

is formed, as is shown by the following analytical data :

I. 2.0000 grams mercuric chloride united with i .4033 grams
ammonia. The compound thus formed lost i .1679 grams am-
monia at 20°.

II. 3.0000 grams mercuric chloride united with 2.0638
grams ammonia. The compound thus formed lost 1.6882
grams ammonia at 20''.

Calculated for Found.

HgCl5.2NH3.ioNH3. I. II.

NH3 lost at 20° 35.79 34.32 33.56

" retained at 20° 7.15 6.92 7.41

The liquid, which is slightly soluble in ammonia, has a
Specific gravity of 1.56, and is stable only under pressure.
At low temperatures it solidifies, and the solid formed melts
at — 9°. If the pressure is removed from this solid, 10 mole-
cules of ammonia are dissociated off, and there remains be-
hind a compound of the formula HgCl5.2NH3, which seems to
be identical with mercuri-diammonium chloride. The com-
pound melts with some decomposition, as does the fusible
white precipitate. Mercuri-diammonium chloride, prepared
by precipitation from a solution of mercuric chloride in a con-
centrated solution of ammonium chloride, when sealed in a
tube with liquid ammonia, takes up 10 molecules of ammonia
to form the heavy liquid described above.

Mercuric Cyanide. — This salt is very easily soluble in am-
monia, even deliquescing in the vapor from the cold liquid.
In water, mercuric cyanide is not at all dissociated,' while in
ammonia it forms a solution possessed of a distinct conduc-
tivity. The molecular conductivity, however, instead of in-
creasing, decreases with the dilution. The decrease is small,
and the rate diminishes as the dilution becomes greater.
Three ^independent measurements on different specimens of
the salt gave similar results in this respect.

1 Ostwald : Wissenschaft Grundlag. d. analyt. Chem., p. 147 (1894).

Electrical Conductivity of Liquid Ammonia Solutions. 301

No instance in which the molecular conductivity decreases
with dilution is known in aqueous solution, but such behavior
has been observed in the case of certain ether and amyl alco-
hol solutions' and in the case of solutions in benzonitrile.'

Silver Cyanide. — Silver cyanide is readily soluble in ammo-
nia, forming a solution which is a fair conductor. As is true
of mercury cyanide, the molecular conductivity of the salt is
low and varies but slightly* with changes in the concentra-
tion. Contrary to the behavior of mercury cyanide, however,
the molecular conductivity of silver cyanide increases some-
what with the dilution.

Ternary Salts. — But one ternary salt, strontium nitrate, has
been measured. It has a much higher molecular conductivity
than the binary salts, and although the dilution was carried
beyond z'= 100,000, the limit was not reached, the ammo-
nia solution behaving in this respect like aqueous solutions of
the ternary salts.

Phenols. — Phenol, thecresols, the dihydroxy benzenes, pyro-
gallol, and guaiacol form solutions which show a distinct
conductivity, while solutions of ortho- and paranitrophenol,
dinitrophenol, and picric acid approach salt solutions in their
power to conduct the current. Accurate quantitative measure-
ments have been made on orthonitrophenol only, which, as
the data given in the tables show, is a very much better con-
ductor in ammonia than in water.^

Nitrohydrocarbons. — The aromatic nitrohydrocarbons are,
so far as they have been tested,^ more or less soluble in am-
monia, forming solutions which in some cases are brilliantly
colored. Solutions of nitrobenzene and of the nitrotoluenes
are but slightly colored and conduct the current but little, if
at all, while dinitrobenzene and trinitrotoluene approach the
salts in their conducting power.

Dinitrobenzene. — The interesting observation was made upon
this substance that the conductivity of its solution upon dilu-

1 Kablukoff : Ztschr. phys. Chem., 4, 429 (1889).

2 Euler : Ibid., 38, 623 (1899).

' Euler {loc. cit.) has observed that the molecular conductivity in nitrobenzene
solutions increases but slightly, if at all, with increasing dilution.
4 Bader : Ztschr. phys. Chem., 6, 296 (1890).
B This Journal, 20, 832 (1898).

302 Franklin and Kraits.

tion did not at once come to its full value, but that the resist-
ance dropped continuously for about half an hour, the total
fall amounting to about 2 or 3 per cent. After reaching its
full value the resistance remained constant. In one experi-
ment the resistance, after becoming constant, did not change
perceptibly after the lapse of fourteen hours. The only anal-
ogous case recorded is an observation by Euler,' who noticed
that when solutions in nitrobenzene were diluted the conduc-
tivity did not become constant until after some time, the total
increase in this case amounting to about 10 per cent. It was
also observed that the blue color of the freshly prepared am-
monia solution gradually changes to a fine red.

It is worth while to note that contrary to the behavior of
dinitrobenzene, no appreciable time was necessary for the
solution of trinitrotoluene to take on its final conductivity
value upon dilution.

Nitromethane . — Nitroraethane, which is miscible with am-
monia, is not dissociated to as great an extent as are the aro-
matic nitro compounds, but it nevertheless forms a good con-
ducting solution. While nitromethane itself is but very
slightly soluble in water, it very readily dissolves in a solu-
tion of an alkaline hydroxide, forming a compound in which
the metal takes the place of hydrogen in the nitromethane.*
No record of measurements of the conductivity of the salts of
nitromethane or of nitromethane itself in aqueous solution
could be found.

Basic and Acid Amides. — The amides of potassium, sodium,
and lithium are fair conductors of electricity in ammonia solu-
tion as are also a considerable number of acid amides.

Of the class of basic amides, measurements of the molecu-
lar conductivity have been made only in the case of sodamide.
In preparing the solution of sodamide a weighed quantity of
metallic sodium was introduced into the resistance cell, when
by the action of the ammonia, the metal was soon changed
into sodamide. The end of the reaction was recognized by
the complete disappearance of the blue color of the sodammo-
nium, and by the final constant value of the resistance of the

1 Ztschr. phys. Chem., 28, 619 (1899).

2 Meyer und Jacobson : L,ehrb. d. organ. Chem., 1, 254 (1893).

Electrical Conductivity of Liquid Ammojiia Solutions. 303

solution. The difficulty of weighing metallic sodium accu-
rately makes a confirmation of the values given in the table
above desirable, a matter which will have the attention of one
of us in the near future. Quantitative measurements of the
conductivity of potassamide and lithamide solutions have also
been made. Sodamide is slightly soluble in ammonia ; potas-
samide is very soluble.

The acid amides generally dissolve readily in ammonia,
most of them forming solutions which are conductors. They
vary a great deal, however, in the extent of dissociation which
they undergo ; benzamide and paracettoluide, for example,
do not conduct the current perceptibly, acetamide and urea
conduct very poorly, while succinimide conducts well, and
metanitrobenzenesulphonamide approaches the salts in the
facility with which its solution conducts the current.

The only measurements so far recorded of the conductivity
of acid amides in aqueous solution are those of Bader' on a
number of substituted cyanamides, of Walden^ on succini-
mide, and of Triibsbach^ on a few ureides. The substituted
cyanamides and some of the substituted ureides form solu-
tions which are fairly good conductors, while the solutions of
succinimide, urea, and some simple ureides are very poor con-
ductors. Qualitative measurements by the authors on a
number of acid amides, including acetamide and benzenesul-
phonamide, justifies the conclusion that in general this class
of bodies is but slightly dissociated in aqueous solution. On
the other hand, ammonia has the power of dissociating many
of them to a very considerable extent, as the measurements
given above show. An interesting question in connection
with these solutions is whether the positive ion is hydrogen or
ammonium. From the action of ammonia on hydrogen ions
in aqueous solution it is to be presumed that the positive ion
is ammonium, but if this is the case it would seem that the
dissociation curves of these substances might be expected to
follow more closely the curves for salts, instead of resembling,
as they do, those of weak acids in aqueous solution. If am-
monium salts are formed in solution they are so unstable that,

1 Ztschr. phys. Chem., 6, 304 (1890).
i Ibid., 8, 484 (1891).
i Ibid., 16, 708 (1895).

304 Franklin and Kraus.

on evaporating away the solvent and warming up to the labo-
ratory temperature, they decompose, leaving behind the free
acid amides.' On the other hand, if the positive ion is hydro-
gen, then the migration of the positive ion is strikingly low.*

Reactions of the Amides in Liquid Ammonia. — If acid and
basic amides bear to ammonia a relation analogous to that
borne to water by the ordinary oxygen acids, then, sinc^ the
former are dissociated in liquid ammonia, they should react in
ammonia something after the manner of acids and bases in
water.

Numerous reactions suggest themselves, a few of which
take place in aqueous solution while others have been carried
out in benzene and other non-electrolytic solvents.' Titherly
especially, in his investigations on the action of sodamide on
a variety of substances, has prepared a number of salts of acid
amides. By continued heating of benzene solutions of form-
amide, acetamide, propionamide, and benzamide, respectively,
with sodamide, Titherly obtained sodium formamide,
HCONHNa, sodium acetamide, CH3C0NHNa, sodium
propionamide, C^H^CONHNa, and sodium benzamide,
C,H,CONHNa.

Only a few such reactions have yet been studied in ammo-
nia solution, and these only qualitatively.

If an ammonia solution of benzenesulphonamide is allowed
to act on sodamide, after a time a well-crystallized substance
separates from the solution which is presumably benzenesul-
phonamide in which sodium is substituted for amide hydro-
gen.

Solutions of benzenesulphonamide, succinimide, benzoic
sulphinide, acetamide, and urea dissolve metallic sodium,
metallic magnesium, and, to some extent, metallic zinc, with
the evolution of hydrogen, and well-crystallized products sep-
arate from the solutions. The amount of hydrogen given off

1 This statement was proved by experiment to be true in the cases of benzoic
sulphinide, acetamide, and benzenesulphonamide. Orthonitrophenol retains i
molecule of ammonia. Trinitrotoluene retains 3 molecules of ammonia.

2 Hydrochloric acid in acetone shows an abnormally low conductivity. Carrara :
Ztschr. phys. Chem., 27, 184 (1898).

8 Dessaignes : Ann. Chem. (Liebig), 82, 231 (1852); Strecker: Ibid., io3, 324
(1857) ; Gal : Bull. Soc. Chim., 39, 647 (1883) ; Curtius : Ber. d. chem. Ges., 23, 3037
(1891) ; Blacher : Ibid., 28, 432 and 2352 (1895) ; Titherly : Jour. Chem. Soc. (London),
71, 461 (1897).

Electrical Conductivity of Liquid Ammonia Solutions. 305

when magnesium was dissolved in a solution of acetamide,
was measured and found to be equivalent to the amount of
magnesium dissolved. In the case of the action of magne-
sium on benzenesulphonamide the volume of hydrogen ob-
tained was much less than the calculated amount, a fact
which may have its explanation in the reducing action of the
nascent hydrogen on the acid amide.

Silver oxide dissolved sparingly in a solution of acetamide,
and copper oxide dissolved in a solution of benzoic sulphinide ;
after a time well-crystallized substances separated from the
solutions, and these were presumably silver and copper salts
of acetamide and benzoic sulphinide, respectively.

In this connection the fact may also be mentioned that, in
general, the salts of ammonium, which bear to ammonia a
relation in some respects analogous to the relation which the
oxj-gen acids bear to water, dissolve the alkali metals and
magnesium, and in some cases other metals, with the evolu-
tion of hydrogen. Ammonium nitrate, for example, dissolves
magnesium very energetically and after a time a well-crystal-
lized product separates from the solution.

Further, on the basis of the relations which the ammonium
salts and the acid amides on the one hand, and the metallic
amides on the other, bear to ammonia as an electrolytic sol-
vent, it ought to be possible to find indicators which give
color reactions in ammonia after the manner of indicators in
aqueous solutions. Such indicators in fact exist,

Phenolphthalein dissolves in ammonia forming a pale-red
solution. Addition of sodamide greatly intensifies the color
of the solution, while in turn the color is completely dis-
charged by addition of benzoic sulphinide or ammonium bro-
mide.

Carmine dissolves sparingly, forming a dirty red solution
which sodamide changes to a fine blue. The blue color is
changed to a fine red by the addition of ammonium bromide.

Saffranine dissolves abundantly, forming a beautiful crim-
son solution. Sodamide or potassamide changes this color to
blue, and acid amides or ammonium salts restore the crimson
color.

The strong colors of a considerable number of other sub-

3o6 Franklin and Kra^Ls.

stances in solution in ammonia, among which may be men- ^
tioned metadinitrobenzene, trinitrotoluene, and orthonitro-^
phenol are but slightly affected by either the addition of basic ^
or acid amides. A large excess of an ammonium salt of an ^
acid amide changes the blue solution of alizarin to a mixed ^
color. ^

The Alkali Metals. — The most remarkable observations >r-
made in connection with the work on liquid ammonia is the
fact that solutions of the alkali metals conduct electricity with (^
great facility, without any separation of products at the elec- ^
trodes and without the least sign of polarization. The au-
thors have confirmed the statements of Cady' to this effect.
The greatest difficulty in the way of measuring the conduc-
tivity of these solutions lies in the fact that the metals react
with the solvent rapidly enough to introduce a large and un-
controllable error. For example 56 mg. of sodium in 45 cc.
of ammonia at its boiling-point, were completely changed into
sodamide in the course of fifteen minutes. An approximate
value of the molecular conductivity of a sodium solution was
obtained by introducing a known weight of sodium into the
resistance cell of the conductivity apparatus, and as soon
thereafter as possible, taking a reading of the resistance.
This gave for v = 18.56, a molecular conductivity of
392.6, or if the molecule be assumed to contain 2 atoms of ^
sodium, as some previous investigators* on these solutions in- /
dicate, then the molecular conductivity becomes 785.2. ^

^ An attempt was made to determine what change, if any, ^
^^^ takes place in the molecular conductivity on diluting the ^'^
solution. To this end the above solution was again measured "^
and, as rapidly as possible, ammonia was added from the re- y^
X ceiver until the second point in the conductivity cell was cov- ^
ered. The solution was then stirred and the resistance read. ^
The molecular conductivity calculated from these two meas-
es urements was for z^ = 18,56, ;/z;= 332.6 ; and for z^ = 27.49,
'^ /^^ — 335-4- Approximate measurements made by Cady^
^ gave for z;=4.28, 3.97, and 3.8, //z; = 420, 441, and 479,

1 J. phys. Chem., i, 707 (1897).

2 Joannis : Compt. rend., 115, 820 (1898).
8 Loc. cit.

Electrical Conductivity of Liquid Ammonia Solutions. 307

respectively. Certainly the molecular conductivity does not
change much with the dilution. Because of a mishap to the
apparatus, further measurements on these solutions have not
yet been made.
jS An attempt was also made to measure the temperature co-
^v efl&cient of the alkali metal solutions, but here too the action
^ between the metal and the solvent interposed a serious diffi-
Ig culty which was only partially overcome by making the meas-
T urements at temperatures much below the boiling-point of
^ ammonia at ^^atmospheric pressure. Under these conditions
^ the temperature which could not be at all accurately deter-
^ mined was found to be between 0.5 and 1.5 per cent per de-
gree, and to be of positive sign.

As stated above, Joannis has shown that in these metallic
solutions 2 atoms of the metal are united with 2 molecules of
ammonia to form, for example in the case of sodium, a com-
pound having the formula Na^N^Hg, to which he has given
the name sodammonium. It has not been shown, however,
that the ammonia combined with the metal in this compound
plays the same part as does ammonia in the ammonium
compounds. The solution behaves in many respects as a sim-
ple solution of the metal in ammonia in which the former is
combined with the ammonia rather after the manner of sub-
stances with water of crystallization than as a constituent of a
stable compound of the ordinary kind. Or the ammonia is
coordinated with the metal in the sense in which Werner uses
this expression. Water of crystallization in combination with
compounds has no efiect on the conductivity of their aqueous
solutions, nor does it take part in the reactions of the com-
pounds as ordinarily considered. The same is in all proba-
bility true of salts with ammonia of crystallization in ammo-
nia solutions. It may be doubted therefore whether the com-
pound sodammonium has anj^ further analogy with the hypo-
thetical compound ammonium than the fact that it may be
brought under the same formula.

The following facts seem to indicate that sodium solutions

1 By comparing the rate of reaction between sodium and ammonia on the one hand,
and sodium and water on the other, some idea of the relative number of hydrogen
ions present in liquid ammonia is obtained. The number must be very much less in
ammonia, which is in agreement with the high resistance found for the pure liquid.

3o8 Franklin and Kraus.

occupy a very interesting position between ordinary electro-
lytic conductors and some vapors.

J. J. Thomson' has shown that sodium vapor is blue, that
it conducts electricity remarkably well, and without polariza-
tion at the electrodes, properties which an ammonia solution
of sodium likewise exhibits. While, however, in the form of
vapor the molecule and atom of the alkali metals are identi-
cal,* in solution in ammonia the molecule contains 2 atoms. ^

Whatever may be the nature of the substance in solution,
it conducts the current with remarkable facility. It would
seem that the process of conduction must consist in the wan-
dering of charged bodies through the solution, and the fact
that the temperature coefficient is of positive sign and of con-
siderable magnitude lends probability to this view.

As there are molecules of but one kind in solution it is im-
possible to assume that i molecule should be able to take on
only a positive charge and another only a negative charge.
Consequently it would seem that one and the same particle
must be able to take on a charge of either positive or negative
electricity with which it wanders to the oppositely charged
electrode, there to loose its charge and to take on one of oppo-
site sign, or meeting an oppositely charged particle to thus
lose its charge.* At any rate enormous quantities of electric-
ity may pass through such solutions without producing any
visible effects other than a deepening of the blue color in the
vicinity of the electrodes in dilute solutions.

Investigations on these metal solutions will be continued
during the present year by one of us (Kraus) in the labora-
tories at Johns Hopkins University.

In the appended plates, in which the ordinates represent
molecular conductivities and the abcissae the cube roots of
the dilution, the dependence of the molecular conductivity
upon the dilution of the solutions is shown graphically.

1 Phil. Mag. (5), 29, 441 (1S90). It is interesting to note in this connection that
sodium chloride which has been heated in the vapor of sodium takes on a permanent
blue color. (Geisel : Ber. d. chem. Ges., 30, 15S (1897).)

2 Scott : Trans. Roy. Soc, Edinburgh, 14, 410 (1887).

3 Joannis : Loc. cit.

4 This is approximately the hypothesis upon which J. J. Thomson explains the
conductivity of the vapor of sodium and some other substances. {Loc. cit.)

Electrical Co7idiiciivity of Liquid Annnonia Sohitio?is. 309

5

,io

Frayiklin and Kraus.

Electrical Conductivity of Liquid Ainmoiiia Solutions. 311

1^ '^S^&<:^<^^S^i^^*^'^S^S

312 Franklin and Krazis.

Summary of Results.

The results of the work described in this paper may be
briefly summed up as follows :

1. The problem of obtaining pure liquid ammonia has been
successfully solved and a form of apparatus has been con-
structed which is well adapted to the study of the conductivity
of liquids of low boiling-points.

2. With a few exceptions salts are dissociated to a less de-
gree in ammonia than in water.

3. The limit of molecular conductivity of binary salts in
ammonia at — 38° ranges from about 290 to 340 Kohlrausch
units, which is much above the conductivity of the same salts
in solution in water at 18°.

4. Ostwald's law of dilution holds approximately for binary
salts. Other solutes have not been tested.

5. Silver iodide is dissociated in ammonia solution, al-
though not to so great an extent as other binary salts.

6. Mercuric chloride reacts with ammonia to form the com-
pound HgCl2.i2NH3, which loses 10 molecules of ammonia
on being warmed up at atmospheric pressure. The com-
pound HgCl2.2NH3 is identical with mercuri-diammonium
chloride.

7. Mercuric cyanide and silver cyanide conduct in ammo-
nia, but the conductivity in neither case changes much with
the dilution. The molecular conductivit}'- of the former falls
slightly, the latter rises somewhat.

8. The one ternary salt measured has a high molecular
conductivity, and, as in water solution, it approaches its
maximum more slowly than do the binary salts.

9. Many of the nitro compounds are good conductors in
ani'.uonia solution. Some of them approach the binary salts
in their power to carry the current.

10. The acid and basic amides generally dissolve in ammo-
nia to form good conducting solutions. The conducting
power of the acid amides ranges from the fraction of a unit to
that of the binary salts.

1 1 . The acid and basic amides may be considered as acid
and bases derived from ammonia in the same manner as the

Evolution of Oxygen. 313

oxygen acids and bases are derived from water. This rela-
tion is borne out by the chemical behavior of the amides in
solution in ammonia and by their action on color indicators.

12. As found b}^ Cady ammonia solutions of the alkali
metals conduct electricity without polarization at the elec-
trodes. The conductivity changes but slightly, if at all, with
the concentration.

These solutions exhibit positive temperature coefficients.

In conclusion, the authors wish to express their apprecia-
tion of the kindness of Professor Lucien I. Blake in placing
at their disposal the facilities of the Department of Physics
and Electrical Engineering.

The University of Kansas,
Lawrenge, September, 1899.

ON THE CAUSE OF THE EVOI.UTION OF OXYGEN

WHEN OXIDIZABEE GASES ARE ABSORBED

BY PERMANGANIC ACID.

By H. N. Morse and H. G. Byers.

It was suggested in a former communication' that the evo-
lution of oxj'gen which occurs when hydrogen or carbon
monoxide is absorbed hy acidified solutions of potassium per-
manganate is due to the action of the peroxide which is
formed upon the excess of the permanganic acid ; and,
further, that the cause of this action of the oxide upon the
acid may be a tendency on the part of the simpler peroxide
molecules to polymerize to more complex ones at the expense
of the acid.

It was affirmed by V. Meyer and M. von Recklinghausen^
that when hydrogen and carbon monoxide are absorbed by a
neutral solution of potassium permanganate, there is no liber-
ation of oxygen. Previous to this, however, it had been
stated by one of us^ that ' ' the reduction of potassium per-
manganate by the superoxide in a neutral solution is too slow
for convenient observation." If, now, the evolution of oxy-
gen which occurs when gases are absorbed by acidified solu-

i Morse and Reese : This Journal, 20, 721.

2 Ber. d. chem. Ges., 29, 2551.

3 This Journal, 18, 413.

314 Morse and Byers.

tions of permanganate is due to the action of the oxide on the
permanganic acid, as maintained by us" in opposition to
V. Meyer and H. Hirtz,^ then the oxide which is formed in
neutral solutions and is inactive should become active whenever
— after the disappearance of the gas — the solution containing
the oxide in suspension is acidified. Our experiments show,
as regards carbon monoxide, that when this gas is absorbed
by neutral solutions of permanganate, there is no evolution of
oxygen ; but when an acid is afterwards added, there is an
evolution of oxygen similar in all respects to that which is
observed when an equal volume of the gas is absorbed by an
acidified solution of permanganate of the same concentration.
Again, if the cause of the reduction of the acid is, as sug-
gested, the tendency on the part of the peroxide to become
more complex at the expense of the acid, then the evolution
of oxygen should gradually diminish in rapidity as the polym-
erization progresses. Our experiments prove that as a mat-
ter of fact the rate of evolution does constantly decrease
whether the gas is absorbed in an acid solution or in a neu-
tral one which is afterwards acidified. It is shown, more-
over, that when the gas is absorbed in an acid solution the
period of rapid evolution does not terminate with the disap-
pearance of the gas as it should if the gas is the direct cause
of the liberation of oxygen.

Finally, if polymerization of the oxide is the
cause of the decomposition of the acid, the
quantity of the gas absorbed remaining fixed,
the volume of oxygen liberated within a
given time should increase with increasing
concentration of the permanganic acid. Our
experiments show that it does so increase.

The apparatus which was eraploj^ed by us is
shown in the accompanying figure. It consist-
ed of a glass tube having a capacity of 100 cc.
The liquid reagents were introduced through
V_^ the larger horizontal stop-cock at the top, and
the gas through the stop-cock in the nearly capillary side-tube.

1 This Journal, so, 521.

2 Ber. d. chem. Ges., 29, 2S28.

Evolution of Oxygen. 315

To make room for the gas within, a volume of air equal to,
or somewhat greater than, that of the gas to be introduced
was first withdrawn from the tube. To secure proper mixing
of the contents and a uniform condition of temperature, the
tubes were attached transversely to a shaft which passed
through a thermostat and was revolved at the rate which ap-
peared to secure the greatest agitation of the contents of the
tube. A nearly constant temperature of 35° was maintained
in the bath. The gas experimented with was carbon mon-
oxide, of which 12 cc. — or the volume which would reduce to
that under standard conditions of temperature and pressure —
were employed in every case. With this fixed volume of car-
bon monoxide, various quantities of potassium permanganate
were agitated both in neutral and in acidified solutions. The
volume of the acidified solutions, however, was always raised
to 50 cc. by the addition of water. 12 cc. of carbon monoxide
reduce 56.44 mgms. of potassium permanganate to the per-
oxide condition, and the weights of the salt introduced into
the tubes were always some multiple of this quantity. Hence
the oxide resulting from the absorption of the gas and the ex-
cess of permanganic acid bore to each other in every case
definite, known, molecular ratios. For example, when 169.32
(:= 56.44 X 3) mgms. of the salt were agitated with 12 cc. of
the gas, the ratio of HMnO^ to MnO^ was 2 to i ; and when
1549.64 (= 56.44 X 31) mgms. of the salt were used, the
ratio was 30 to i . The ratios actually employed were 2:1,
5:1, 10 : I, 15 : I, 20 : I, 25 : i, 30 : i, and in one case 7.5 : i.
In working with acidified solutions, the same degree of acid-
ity was always produced, the quantity of sulphuric acid
which was added being in every instance equivalent to the
potassium in the permanganate reduced by the gas plus three
times the potassium in the excess of the salt. The amount of
the reduction was measured by titrating the contents of the
tubes, after agitation, against standard solutions of oxalic
acid or of potassium tetroxalate.

Our first step was to determine the length of time required
to absorb the gas by neutral solutions of various concentra-
tions. The results are given in Table I.

3i6 Morse and Byers.

Table I.

Ratio of
HMnO, to Mn02.

Time of
agitation.

CO unab-
sorbed.

Apparent
reduction.

Hours.

cc.

cc. of Oj.

2 : I

5

I.O

—0.08

5

0.85

— O.IO

9

0.2

O.OI

9

0.4

— O.OI

10

0.0

— c 02

10

0.0

O.OI

5 : I

3

0.6

— 0.14

3

0.2

— 0.00

4

0.2

— 0.02

4

0.4

0.03

5

0.0

0.03

5

0.0

0.03

lo : I

li

1-3

—0.13

li

1-5

—0.13

2

0.0

—0.13

2

0.0

— 0.26

20 : I

I

0.4

— 0.26

I

0.9

—0.87

li

0.4

— 0.07

li

0.0

0.00

2

0.0

0.00

2

0.0

—0.53

30: I

I

0.3

— 0.09

I

0.2

0.26

li

0.0

0.17

Having found the time which neutral solutions of various
concentrations required for the complete absorption of the
gas, we proceeded to ascertain what would happen if, after
the absorption, the solutions were acidified. In Table II,
which gives the conditions and results of our experiments in
this direction, the duplicates are bracketed together, and let-
ters are employed to indicate what tubes were in the bath at
the same time.

Evolution of Oxygen.

317

r«<^/^ //.

Ratio of
HMn04 to MnOj. Hours oi

agitation.

Oxygen
liberated.

Percentage
reduction.

Neutral.

Acid.

cc.

-■ 1"

24
24

0.89
0.98

7-34
8.37

f 22

24

1. 16

9.76

I 22

24

0.98

8.37

\ 26

24

1.06

8.92

1 26

24

I. 14

9-65

i i3i
li3i

150

5-67

47-51

150

5.66

47-39

5:: a{4

24
24

1.88
1-45

6.29

4.87

^{^

00

0.06

....

00

0. II

....

bl^4

24

1.68

5-67

^124

24

1.74

5-84

■ Mis

00

0.06

....

00

0.06

....

|4

150

7-44

24.85

(4

150

7-44

24-85

c|^

24
24

2.09
2.15

3-51
3-57

c|"4

00

—0.13

....

M24

00

— 0.06

....

dj ^4

24

2.29

3-82

• (24

24

2.35

3.89

^{t

00

0.00

....

00

0.06

....

|3

150

11.46

18.33

l3^

150

II. 17

18.04

20:1 e{;|

24
24

3-40

3.54

2.84
2.94

e i 25i

00

0.13

....

^l25i

00

0.07

....

f (24

00

0.00

....

I24

00

—0.33

....

f|'

24

3.00

2.50

I2

24

3.00

2.50

j24

24

3-24

2.61

(24

24

3-75

3.01

P-|48

00

— 0.06

....

^{48

00

0.06

....

1'

24

3-34

2.77

(2

24

4.00

3-33

1^

150

11.62

9.69

I2

150

12.95

10.78

3i8

Morse and Byers.

30

li

24

4-56

2.54

li

24

5.10

2.86

24

00

— 0.09

....

24

00

—0.17

24

24

4-74

2.62

24

24

5-42

3.01

48

00

0.35

....

48

00

0.52

....

2

150

18.40

10.10

2

150

19.27

10.84

We next proceeded to determine how long a time acidified
solutions of permanganate of different concentrations require
for the absorption of the gas, and what volumes of oxygen are
liberated previous to the disappearance of the last traces of
the gas. Table III gives the results :

Table III.

Ratio of

Time of

CO unab-

Ojlibera-

Percentage

1O4 to MnO^.

agitation.

sorbed.

ted.

reduction.

Hours.

cc.

cc.

2 : I

5

0.85

0.22

1.76

6

0.60

0.28

2.25

7

0.35

0.29

2.51

8

0.0

0.34

2.85

8

0.0

0.34

2.85

5: 1

2

1.65

0.73

2.39

2

0.95

0.53

I.4I

3

0.0

0.88

2.92

3

0.0

0.88

2.92

10 : I

li

0.55

1.65

2.71

I*

0.20

1.40

2.27

2

0.0

1.84

3-04

2

0.0

1.65

2.73

20 : I

I

2.6

2.80

2.31

I

0.9

2.80

2.33

4

0.0

3.33

2.77

A

0.0

3-74

3-II

30: I

I

0.30

5-27

2.92

li

0.0

5-36

2.98

li

0.0

5-63

3.00

Finally, we absorbed the gas in acid solutions of various
concentrations, agitated for periods of 6, 24, and 150 hours,
and determined the amount of oxygen which had been liber-
ated. The results are contained in Table IV.

lo : I

Evolution of Oxygen. 319

Table IV.

Time of agitation.

6 hours. 24 hours. 150 hours.

V

cc. cc.

CO not all absorbed | °'^° 5'^^
0.72 6.07

0.71 5-95
1.49 4.96 uf2.46 8.21

5-^ ^(1.35 4-46 (2.30 7-64

I 1.90 4.25 e|^-77 ^.16

72-1 li-90 4.25 (2.77 6.16

2.06 4.37 H I 2.77 6.16

V

d

V 3

cc.

1. 91

16.02

2.49

20.81

3.88

12.99

3.88

12.99

5.80

12.91

5-96

13-25

2.94 6-49
2.93 4-90 ^f3-57 5-95 d 7-8o 13-05

2.63 4.90 (3-57 5-95

3.20 5-34 „J3-84 6.43 t, f 7-8o 13-05

2.89 4.84 *'l3-84 6.43 1 7-64 12.79

3.20 5.34 (3-87 6.49

13-I3 5-21 (4-14 6.87

,{3.84 4-21 (5-26 5-78 v.i 9 54 10.47

15:1 U3-87 4-24 15-26 5-78 1 9-70 10.84

J 4-79 3-99 15-89 4-89 j f 10-75 8.86

^°-^ 1 5.13 4.29 (5-75 4.75 1 11-44 9.51

5.10 4-24 V I 5-30 4-38 hi 10.81 8.99

4.62 3.68 1 I

.95 4.14 T,f5-74 4-72 (10.81 8.99

.30 4.38 (5-89 4-90 (11-03 9-16

3.92 1^1 6.06 4.02 ^113.66 9.09

(5-;

^^•^ ^5-90 3-92 ^l6.37 4-24 '1 14-30 9-39

f 6 ^8 -; '^-^ , i 7-48 4-15 r 15.25 8.46

It appears from Table I that when carbon monoxide is ab-
sorbed by a neutral solution of potassium permanganate there
is no liberation of oxygen during the absorption ; and from
certain experiments included in Table II, where no acid was
added, it appears that the neutral permanganate may be agi-

320 Morse and Byers.

tated for many hours with the peroxide which is produced in
it by the absorption of the gas without suffering any sensible
reduction. The inactive state of the oxide under these condi-
tions may be due to the fact that the salt is more stable than
the acid, or to the fact that the peroxide precipitated in a
neutral solution contains large quantities of potassium and is
therefore already saturated ; or, what is more likely, the fail-
ure to liberate oxygen may be due to both of these causes.
As regards the quantity of alkali which such an oxide may
contain, it has been shown' that when a neutral solution of
the permanganate undergoes complete, so-called spontaneous
reduction to the peroxide, the precipitate contains the whole
of the potassium.

Table II shows that when carbon monoxide has been ab-
sorbed by an excess of neutral permanganate, giving an inact-
ive oxide, and the liquid is afterwards acidified, there is a
liberation of oxygen just as when the gas is absorbed by an
acid solution. Moreover, the general characteristics of the
reaction are the same in both cases, pointing to a common
cause. The amount of oxygen liberated within a given time
increases with the concentration of the acid, and the rate of
evolution in any given case decreases with time, the decrease
being most marked in the more concentrated solutions. These
phenomena are most easily explained by supposing the per-
oxide molecule in its simpler state to be unsaturated in the
sense that it is capable of uniting with other molecules of its
own kind and that its power to do this enables it to break up
adjacent molecules of permanganic acid. Its failure to liber-
ate oxygen when formed in neutral solutions would be ex-
plained, as previously stated, by the fact that when it is so
formed it is in combination with potassium.

Table III shows that when a fixed quantity of carbon mon-
oxide is absorbed by acid solutions of permanganate, the
quantity of oxygen which is liberated during the absorption
increases with the concentration of the solution. This result
was anticipated and the experiments were made with a view
to testing the hypothesis as to the cause of the liberation of
oxygen. It was reasoned that if the reduction of the acid is

I This Journal, i8, 411.

Evolution of Oxygen. 321

due to the inclination of the peroxide molecules to abstract
still other molecules of the oxide from the acid in order to
unite with them, then the rate of the reduction, and conse-
quently of the liberation of oxygen, should increase with the
concentration of the permanganic acid.

From Table IV it appears that the quantity of oxygen
which is liberated in a given period after the gas has disap-
peared increases with the concentration just as it does during
the absorption, and as it does also when the gas is first ab-
sorbed in a neutral solution to which acid is afterwards added.
Moreover, the rate of evolution diminishes with time in the
former as it does in the latter case. Nevertheless, the evolu-
tion is still relatively rapid for a time — especiall}' in the more
dilute solutions — after the disappearance of the gas, as if the
causes of the evolution during the absorption and afterwards
were identical. These relations will be rendered clearer by
an inspection of Table V, in which the averages of the results
contained in Tables III and IV are given :

Table V.

I hta

Agitation. Agitation Agitation.

6 hours. 24 hours. 150 hours.

HZ -a« .-g

ami; _.tn., RaO"- tS V

>o. "uhh •;;iJ>« flg.S°* o c??

5^-? ,u.co °.HO 0^.2 ««^ > l-S.

■3 a

.220

psXS h>2-j o.9'i Ph-oSo o fc-c o Ch-o

2:1 8 0.34 2.85 0.74 6.24 2.20 18.42

5:1 3 0.88 2.92 1.42 4.71 2.38 7.93 3.88 12.99

72:1 1-95 4-29 2.81 6.24 5.88 13.08

10:1 2 1.75 2.89 3.05 5.09 3.81 6.35 7.75 12.99

15:1 3.86 4.23 5.26 5.78 9.62 10.66

20:1 4 3.54 2.94 4.82 4.12 5.71 4.73 10.97 9-II

25:1 5-90 3-92 6.22 4.13 13.98 9.24

30:1 li 5.50 2.99 6.45 3.55 7.43 4.12 16.04 8.91

A comparison of Tables II and IV will show that the oxide
formed in acidified solutions is, in general, — especially in the
more concentrated ones — more active during the first twenty-
four hours than that formed in neutral solutions ; while if the agi-
tation is continued for one hundred and fifty hours, the latter

322 Morse and Byers.

oxide exhibits, in all cases, the greater activity. Table VI,
in which averages are given, will show this more clearly.

Table VI.

24-iiour period.

150-hour

period.

Ratio of

Acid. Neutral.

Acid.

Neutral.

HMn04 to MnO^.

Oj cc O5 cc.

O5 cc.

O3 cc.

2 : I

0.74 1-03

2.20

5.67

5 : I

2.38 1.69

3.88

7-44

ID : I

3.81 2.22

7-55

11.29

2o : I

5-71 3-38

10.97

12.28

30 : I

7-43 4-95

16.04

18.84

If we grant that the evolution of oxygen, when the per-
oxide is agitated with an acidified solution of permanganate,
is due to the abstraction of more peroxide from the acid with
subsequent polymerization, and that the decline in the ac-
tivity of the oxide is a consequence of such polymerization,
the question naturally arises whether polymerization may not
also take place between those molecules which are formed in
consequence of the oxidation of the gas, as well as between
these and others which must be derived from neighboring
molecules of the acid. The experience of V. Meyer and M.
von Recklinghausen' seems to indicate that such a polymeri-
zation may occur. It was found by them that when hydrogen
or carbon monoxide is allowed to stand quietly over an acidi-
fied solution of permanganate, there is little liberation of oxy-
gen ; in other words, the agitation of the gas with the solu-
tion is essential to any considerable evolution of oxygen.
The explanation which we would suggest for this phenome-
non is that the absorption and oxidation of the gas taking
place only at the surface of the liquid, the solution becomes
dilute at that point, and the molecules of peroxide therefore
unite with each other to a great extent instead of with mole-
cules of oxide derived from the acid. It may be due in part
to the same cause that the evolution of oxygen during the
absorption of the gas is so much more rapid in concentrated
than in dilute solutions.

Chemical Laboratory,

Johns Hopkins University,

February, 1900.

1 Loc. cit.

Contribution from the Chemical Laboratory of Wesleyan University.

ABSORPTION APPARATUS FOR ELEMENTARY
ORGANIC ANAIvYSIS.

By Francis Gano Benedict.

Since the time of Liebig, granulated calcium chloride and
potassium hydroxide solution have been almost universally used
for the absorption of water and carbon dioxide, respectively, in
elementary organic analj^sis. Numerous forms of apparatus for
holding these reagents have been devised but no satisfactory
substitute for either absorbent has been generally accepted.
In a former article' a special form of soda-lime that had given
satisfactory results in the absorption of carbon dioxide was
described, and it was mentioned that sulphuric acid was used
to absorb the water formed in the process of the combustion.
In the system here described sulphuric acid is used as the ab-
sorbent of water and soda-lime as the absorbent of carbon di-
oxide.

A fundamental error of most absorbing S3'stems, including
the one described in the article referred to, is the unequal dry-
ing w^hich the gases receive on entering and leaving the car-
bon dioxide absorber. All dehydrating agents have not the
same absorptive power, and hence a gas dried by one reagent
will differ considerably in absolute moisture content from that
dried by another. It is essential in determining the correct
weight of carbon dioxide that no moisture be added to or re-
moved from the absorbing system. In the earlier forms no
provision was made to collect the moisture carried away by
the gas which passes through a potash bulb, as it was con-
sidered that the moisture and carbon dioxide of the air used
in the final aspiration, counterbalanced any error arising from
evaporization of moisture." As generally conducted at pres-
ent the gas dried by fused calcium chloride enters the potash
bulb and escapes through a small extension tube containing
fragments of solid potassium hydroxide, and, while it is true
that the issuing gas js thereby dried, it is by no means true

1 J. Am. Chem. Soc., 21, 3S9.

* Die :Entwicklung der organischen Elementaranalyse, W. Dennstedt. p. 21.

324 Francis Gano Benedict.

that it is dried to the same degree as it was before entering
the carbon dioxide absorbing system. Where the greatest
refinement of method is not required this unequal drying may
be considered negligible. In the method of combustion in
oxygen gas, already referred to/ but a small quantity of gas
(700 to 1000 cc.) issues from the carbon dioxide absorbers,
and consequently the error is not great. Where, however, a
current of air instead of oxygen is used in the combustion,
sufficient gas may pass through the system to exert a material
influence on the result if the gas is unequally dried.

While doubtless different drying agents produce the great-
est differences in the absolute amount of moisture remaining
in a gas, the same drying agent will not always produce the
same result, and as Dudlej^ and Pease^ have said, the mechan-
ical condition as well as the freshness of calcium chloride may
be a serious source of error when two different forms of this
reagent are used for drying the gas before and after leaving
the absorber.

Calcium chloride, being a solid, has many advantages over
sulphuric acid, a liquid, for the absorption of water vapor.
It is, however, not without its disadvantages. Probably the
greatest difficulty in its use is the fact that it often contains
basic chlorides, which absorb carbon dioxide as well as water.
This impurity is so constantly present that it becomes neces-
sary to pass dry carbon dioxide through a freshly filled cal-
cium chloride tube for several hours before the basicity is de-
stroyed. It is then necessary to remove the carbon dioxide
by passing a current of dry air through the tube for some
time. But as Winkler^ has shown, this operation of satura-
ting the calcium chloride is not thoroughly remedial since it
is only the surface of the lumps of calcium chloride that is
thus saturated, and later, as the solid absorbs water and deli-
quesces, fresh surfaces of basic chlorides are exposed and con-
sequently carbon dioxide retained.

Moreover, calcium chloride deliquesces when used for some
time, and the semiliquid portions are liable to clog the tube

1 J. Am. Chem. Soc, 21, 3S9.

2 Ibid., 15, 540.

8 Ztschr. anal. Chem., 21, 545.

Absorption Apparatus. 325

and prevent the passage of the gas. A number of j^ears ago
Lowe' suggested a simple remedy for this, however, which
consists in greasing the inside of the U-tube with clean tallow,
and thus preventing the liquid from adhering to the walls.

Concentrated sulphuric acid, though a liquid reagent, has
advantages that would seem to outweigh those of calcium
chloride for use as an absorbent. It is a much better dehy-
drating agent than calcium chloride, does not retain carbon
dioxide, and, in addition, serves to indicate the rate of pas-
sage of the gas. In an actual experiment to show the great
avidity of this reagent for water, 64 grams of ordinary com-
mercial concentrated sulphuric acid contained in a Drechsel
gas washing bottle removed nearly 1 1 grams of water from an
air current passing at the rate of i liter per minute. Less
than o. I gram remained unabsorbed in the air leaving the ab-
sorbing bottle.

A property of sulphuric acid which is often of value in
making combustions, is the fact that if unburned carbonaceous
volatile products escape from the combustion tube they are
mainly retained by the sulphuric acid, which soon becomes
blackened. This indication often saves much time in fore-
stalling unnecessary weighing and calculating.

lu combustions of most organic substances more water is
generally formed than is sufficient to saturate the gas leaving
the combustion tube ; hence, a varying amount of water con-
denses about the stopper in the exit end of the tube. The
water formed in the process of a combustion is generally col-
lected in a U-tube having a bulb on the arm nearest the com-
bustion tube, which serves to collect the condensed water and
thus to prevent unnecessary exhaustion of the absorbing
agent. As this bulb fills it may be emptied, and consequently
a number of combustions may be made with the same absorb-
ing tube. The Volhard and the Marchand form of U-tube are
most commonly used.

In the absorber indicated in the figure a small glass vial
placed in one limb of a plain 5-inch U-tube f of an inch in diam-
eter serves the purpose of the bulb in the earlier forms. This
vial, which should be 3 or 4 mm. less in diameter than the

iZtschr. anal. Chem., ii, 403.

326

Frajicis Gano Benedict.

U-tube, is so supported on a bit of glass rod flattened at one
end that the glass tube conducts the products of combustion
into the neck of the vial. Water condensing in the tube falls
in drops to the bottom of the vial and the gas saturated with
aqueous vapor at the temperature of the apparatus passes
through the U-tube into the carbon dioxide absorbers.

A plug of coarse glass-wool is inserted in the other arm and
extends from the cork to the point where the bend begins.
Enough commercial concentrated sulphuric acid is slowly

Fig. I.

poured through the glass-wool to saturate it thoroughly and
just seal the bend at the bottom of the (J in such a way that
the gas will have to bubble through it. The lower end of the
glass-wool will then be about i centimeter above the surface
of the liquid, the air space preventing too much acid from
being carried up mechanically into the glass-wool. When
this happens it is not unusual for the acid to be carried over
into the carbon dioxide absorbers. The air space is other-
wise valuable as it permits isolation of each bubble and con-
sequently better regulation of the rate of the combustion. If
the bend is just sealed, the minimum pressure only is neces-
sary to force the gas through the tube. The greater part of
the water vapor is retained by the acid in the bend of the
tube as the gas bubbles through, while the last traces are re-
moved by the acid adhering to the glass-wool. Thus in one
plain U-tube are incorporated three distinct drying operations ;

Absorption Apparatus. 327

condensation of excessive moisture, removal of the major part
of the water vapor, and final absorption of remaining traces of
moisture. The tubes are closed with well-fitting, one-holed
rubber stoppers furnished with glass elbows. One elbow ex-
tends far enough below the stopper to be thrust into the neck
of the vial. The tubes are finally closed with short bits of
red rubber tubing fitted with short glass plugs. Inasmuch as
all the tubes in the absorbing train can be used for a number
of combustions before refilling, the rubber stoppers can be re-
placed by corks which are crow^ded down and cut off flush
with the ends of the (J-tube. The corks may then be coated
with sealing-wax. This precaution was not taken in the de-
terminations reported in the following article. Rubber
stoppers gave entire satisfaction. A tube prepared in this
manner maj^ safely be relied on to absorb about i gram of
water vapor exclusive of the water condensed in the vial. In
a series of experiments on the combustion of sugar where ap-
proximately 0.12 gram of water was weighed each time, it was
found that about three-fourths of the water condensed in the
vial. No direct estimate can be made, however, on the length
of time such a tube will last, though if the vial is marked
with a file scratch at the points indicating cubic centimeters
and the amount of condensed water deducted from the in-
crease in weight of the tube, a ready check on the amount of
water vapor actually absorbed is at hand.

This form of absorber is characterized by great efficiency.
As sulphuric acid is a much stronger dehydrating agent than
calcium chloride, less moisture remains in the air current.
Repeated tests have shown that all the moisture that can be
retained by sulphuric acid will be absorbed in such a tube
when the air current is much faster than would ever be per-
missible in the process of a combustion (150 cc. per minute) , a
rapidity of desiccation unattainable with calcium chloride.
The use of a liquid absorbent renders the attachment of a
special apparatus to indicate the rate of flow unnecessary.
Where potassium hydroxide solution is used to absorb the
carbon dioxide no indicator is needed, but in systems using
solid absorbents for both water and carbon dioxide it has been
customar}'- to insert between the combustion tube and the

328 Francis Gano Benedict.

water- absorbing tube a small U-tube containing either mer-
cury, water, or sulphuric acid' to note the rate of flow.

This form of U-tube is very eas}- to wipe dry with a cloth
while other forms, including as they do bulbs and enlarge-
ments, are not so readily cleaned.

The friability of many other forms of drying apparatus is
not shared by this form. Plain glass U-tubes are not, of
course, indestructible, but when properly handled the risk of
breakage is very small, while if broken they can be replaced
at one-half the cost of any other form.

The carbon dioxide absorbing system is a slightly modified
form of that described in the article previously referred to,^
and consists of a U-tube containing specially prepared soda-
lime followed by a U-tube one-third filled with soda-lime and
two-thirds filled with pumice stone saturated with concentra-
ted sulphuric acid. This differs from the earlier form in the
substitution of the pumice stone and sulphuric acid for cal-
cium chloride as a final dryer in the train. The actual
amount of moisture leaving a soda-lime tube is small, not
more than 3 to 5 mgms. per liter of gas escaping from the ab-
sorbers, and of this quantity the greater portion would be re-
tained by calcium chloride, as was found by repeated tests,
but of necessity there would still be a loss of moisture
amounting to from 0.5 to i mgm., that in accurate work should
not be neglected. Sulphuric acid, on the other hand, retains
all of the moisture, i. e. the issuing gas is dried to the same
extent as that which enters.

The soda-lime is practically a mixture of equal weights of
sodium hydroxide and calcium oxide to which sufficient water
has been added to slake the lime and dampen the whole mix-
ture. The preparation of this form of soda-lime is very sim-
ple. One kilogram of commercial caustic soda " Greenbank
Lye" is dissolved in 750 cc. of water in an iron kettle and i
kilogram of finely-pulverized quicklime is added to the solu-
tion with constant stirring until the lime is slaked and the
water is all absorbed. The product is then broken into lumps

1 MonatshefteCiSSg), 39S; Ann. Chem. (Liebig), 285, 3S5 ; Ztschr. anal. Chem., 11,

403.

2 J. Am. Chem. Soc, 21, 3S9-

Absorption Apparatus. 329

and, after cooling, placed in securely sealed bottles. For use
it should be damp but not so moist that the particles glisten
in strong light. If too dry it is easily moistened by adding a
few drops of water and rubbing up in a mortar. If too much
water is accidentally added the mixture may be brought to
the proper consistenc}^ by the addition of dry soda-lime. The
finished product should be pulverized as finely as is consistent
with the passage of the gas. For use in the carbon dioxide
absorbers the pieces should not be larger than 2 mm. in diam-
eter. As the soda-lime is damp there is no danger that par-
ticles will be carried along mechanically with the gas.

The second tube of the carbon dioxide absorbing system
serves the dual purpose of retaining any moisture lost from
the first soda-lime tube and. any traces of carbon dioxide that
might escape absorption in the first tube in case it became
exhausted. With soda-lime the change in color is a very ac-
curate indication of the absorption of carbon dioxide, and
hence it is only necessary to replace the tube with a fresh one
before it has been completely whitened.' The increase in
weight of the second tube is ordinarily not more than 7 mgms.
for each combustion, and, consequentl)'-, when the increase is
greater it is an additional sign that the first tube is nearly ex-
hausted.^ It has been the custom in this laboratory to use
the first tube until the increase in weight of the second tube
is more than 10 mgms. One arm and the bend of the second
tube of the carbon dioxide absorber is filled with dry lump
pumice stone. Concentrated sulphuric acid is then allowed
to trickle slowly down over the pumice until it becomes thor-
oughly saturated, but there must not be acid enough left in
the bottom of the U-tube to seal the bend. A 10 mm. layer of
glass-wool is then laid over the pumice-stone in the partially
filled arm and the remaining space filled with soda-lime. The
glass-wool must not come in contact with acid at any point.

In case sufiicient carbon dioxide to exhaust the soda-lime
does not enter the tube, it should last for 25 or more combus-
tions, since the sulphuric acid would completely absorb at

1 J. Am. Chetn. Soc, 21, 394.

2 A tube freshly filled with soda-lime will last for from 6 to 14 combustions, the
number depending on the size of the lumps of soda-lime, the quantity in the tube,
and the weight of carbon dioxide absorbed in each combustion.

330 Francis Gano Benedict.

least 0.5 gram of water ; and if lomgms. were retained from
each combustion the possible efficiency would be 50 combus-
tions. The ease with which the last tube is prepared, how-
ever, renders it more satisfactory to change it after 25 or 30
combustions.

An absorbing system consisting of three separate pieces
necessitates, it is true, an additional weighing with its delays
and possible error. While the introduction of error in weigh-
ing the third tube cannot be avoided, this form of water ab-
sorber does away with the necessity of shaking the water out
of the bulb after each weighing, and consequently a weighing
with its possible source of error is avoided. The number of
weighings required is the same in each case. Furthermore,
in many forms the carbon dioxide absorber is in two pieces,
and, in such cases, the advantage in accuracy and weighing
lies with the system under consideration.

Aside from the great efficiency of the absorbing agents
which have been discussed elsewhere' the greatest advantage
to be derived from this form of absorber is the abilit}^ to make
accurate analyses independent of the weather. The conden-
sation of moisture, not to speak of gases on the surface of
potash bulbs and other similar forms of absorbers, is a fluc-
tuating factor dependent on atmospheric conditions, and it has
been considered impossible by some^ to make accurate deter-
minations of carbon and hydrogen in damp or stormy weather.
That the condensation of moisture on the surface of the ab-
sorbing system is not a negligible factor is seen from the pre-
cautions ordinarily given to wipe the absorber and allow it to
stand in the balance room for at least half an hour. While
doubtless this procedure gives a close approximation to cor-
rect results, the differences in the amount of condensation, on
days in which the atmospheric conditions are not the same,
are very considerable. When the conditions to which the
glass is exposed in the course of a combustion are considered,
i. <?., the wiping, the handling with moist fingers, the sojourn
of at least an hour in close proximity to a combustion furnace,
together with the considerable internal heat from the absorp-

1 Loc. cit., p. 393.

2 J. Am. Chem. Soc, 15, 451 ; and 20, 528.

Absorption Apparatus. 331

tion of the carbon dioxide by the reagent, the assumption that
the surface condition remains the same after as before, even
with all precautions, is rather broad.

It is possible, however, to have constant surface conditions
before and after analysis. By carefully wiping the absorber
with clean, dry cheese-cloth it is possible to clean the appa-
ratus till there is no longer any loss in weight. This point is
taken as the standard condition, and the tubes are so wiped
before and after each combustion. In an operation of this
kind, the simpler the form of the absorber and the smaller the
surface, the more readily can the apparatus be brought into
condition for weighing. Such a method would be impossible
when applied to a lyiebig or Geissler potash bulb.

The operation as practiced in this laboratory with many
hundred combustions, including those reported in the accom-
panying paper, is as follows : A piece of stout copper wire is
so bent as to hang on the arm of the balance and act as a hook
on which a U-tube can be readily supported, The rubber
plugs are removed from the first IJ-tube, which is then wiped
thoroughly with a piece of clean, dry cheese-cloth in each
hand in such a way that the glass does not come in contact
with the fingers. It should receive a very hard, thorough
rubbing. The tube is then placed on the balance and brought
to equilibrium and then removed, thoroughly wiped again,
and weighed. It will probably lose somewhat in weight.
The operation is continued until the weight remains constant.
After a little experience it is seldom necessary to wipe the
tube more than three times. No difficulty was experienced
with the electric charges noted by Miller.' The tube is then
•plugged and the weight recorded. At the end of the combus-
tion the operation is repeated and the condensation on the
surface of the glass thereby eliminated. The importance of
using clean, dry cheese-cloth cannot be too much emphasized.
A tube so cleaned rapidly increases in weight owing to the
condensation on its surface, but the increase is not too rapid
to prevent making an accurate record of the weight.

To make an especially efficient purifier for the air or oxy-
gen used in the combustion, the reagents may conveniently

1 J. Am. Chem. Soc, 20, 428.

332

Francis Gano Benedict,

be placed in a calcium chloride jar. The gas is conducted
through sulphuric acid placed in the lower compartment of
the jar, through soda-lime filled in around a large glass tube
thrust through the constriction, and after descending to the
bottom of the jar, issues over a long column of pumice-stone
drenched with concentrated sulphuric
acid. The details of construction are
showm in Fig. 2.

A " 12-inch" calcium chloride jar,
preferably with the tubulature as near
the top of the lower compartment as
possible, is selected, and a piece of
glass tubing, of an external diameter
a little less than the internal diameter
of the constriction in the jar, is cut off
long enough to rest on the bottom, and
to reach to within 30 mm. of the top of
the jar. A cork on the end of a glass
rod is loosely inserted in the upper
end of the tube and a layer of glass-
wool or long-fiber asbestos is packed
around the tube to a depth of 3 or 4
mm. Soda-lime prepared as described
above and pulverized into pieces ap-
proximately 2 mm. in diameter is then
introduced, and the jar filled to within
I centimeter of the top of the inner
tube. A " 12-inch" jar will require
about 175 grams of soda-lime. Along
glass tube, approximately 10 mm. external diameter, is
thrust through the one-holed rubber stopper inserted in
the mouth of the jar. This tube is slightly tapered at
the lower end and is filled with pumice-stone, which is
subsequently drenched with concentrated sulphuric acid.
The glass tube extends from about 10 mm, above the stopper
to within 20 mm. of the bottom, and should be of a diameter
small enough to slide easil}' through the upright tube passing
through the constriction in the jar. The upper end of the
tube is closed with a one-holed red rubber stopper carrying a

Fig.

Absorption Apparatus. 333

glass elbow and a piece of rubber tubing with a screw pinch-
cock. This stopper may be sealed with paraffin or wax if de-
sired.

Concentrated sulphuric acid is poured down the central
tube, thoroughly drenching the pumice-stone and collecting
in the base. The first lot of acid should be poured out of the
tubulature and finally sufficient acid poured through the tube
to fill the lower compartment to within 5 mm. of the one-holed
rubber stopper which has been inserted in the tubulature.
The cork is then replaced in the upright tube and the screw
pinch-cock closed. A glass tube bent downward is thrust
through the hole in the rubber stopper in the tubulature in
such a manner that a current of gas passing through it bub-
bles through the acid in the base of the jar. The gas then
rises, passing through a long column of soda-lime at a very
slow rate, turns and passes down through the annular space
between the two glass tubes, and finally, entering the base of
the tube filled with pumice-stone, issues at the top. The
greater portion of the water is removed as the gas bubbles
through the acid ; the carbon dioxide is completely removed
by the soda-lime and the unabsorbed moisture, including that
lost from the slightly moist soda-lime, is removed as the gas
passes over the pumice-stone and sulphuric acid. The gas
issuing at the top is free from carbon dioxide and as free from
moisture as is possible with sulphuric acid.

The ordinary form of " 12-inch" calcium chloride jar has
the tubulature in such a position that about 20 cc. of acid can
be introduced without flowing out of the orifice or coming in
contact with a rubber stopper inserted in the tubulature. A
jar having the tubulature nearer the top is preferable and may
be obtained at a slight increase in cost. ' The chief advantage
of the form of jar having the tubulature near the top of the
base is that there is less liability of getting concentrated acid
on the rubber stopper in the tubulature. The extra amount
of acid that can be placed in the lower compartment increases
the length of service of the purifier, but 20 cc. of acid will, it
is calculated, remove 6 grams of water vapor from the air. If

1 WhitaU, Tatum & Co., of Philadelphia, have furnished the writer with several
12-inch jars with the tubulature inserted at various specified points, with but slight
addition to the price of stock jars.

334 Francis Gano Benedict.

the temperature of the gasometer is taken as 28° C, the gas
leaving it would contain 27 mgms. of water vapor per liter.
An average of 1.5 liters of oxygen are used for each combus-
tion in the method as here conducted, hence the amount of
acid conveniently placed in the base of a regular " 12-inch"
jar would sufl&ce for 200 combustions.

In case the sulphuric acid should become exhausted, it is
only necessary to drain the acid out of the lower compartment
through the tubulature and pour fresh acid through the tube
containing pumice-stone to regenerate the purifier. This is
done in this laboratory after every 50 combustions. The
soda-lime need not be renewed until it becomes three-fourths
white.

MiDDLETOWN, CONN.

Contribution from the Chemical Laboratory ofWesleyan University.

THE EI.EMENTARY ANAIvYSIS OF ORGANIC SUB-
STANCES CONTAINING NITROGEN.

By Francis Gano Benedict.

The chemical processes involved in organic elementary
analysis where the combustion of a substance is made with
cupric oxide are, as a rule, extremely simple. When carbon
and hydrogen, with or without oxygen, are the only elements
in the substance, the carbon is burned to carbon dioxide and
the hydrogen to water. When, however, the molecule con-
tains nitrogen the reaction is not so regular, for while in many
cases all of the nitrogen is liberated uncombined, in certain
classes of compounds a portion, at times a no inconsiderable
portion, is combined with the oxygen of the molecule, of the
gaseous medium, or of the cupric oxide, in the form of nitric
oxide, which in the presence of free oxygen forms nitrogen
peroxide. This latter compound, whose presence is shown
by the appearance of red fumes in the exit end of the combus-
tion tube and by the acidity of the water condensed in the
small bulb of the water-absorbing tube, introduces a serious
error in the determination of carbon and hydrogen, owing to
its solubility in most of the reagents ordinarily used for the
absorption of water and carbon dioxide. While in many in-

Elementary Analysis of Organic Substances. 335

stances the influence of this abnormality is so slight as to be
unimportant, its possibilities are great enough to necessitate
special modifications of the methods of combustion to elimi-
nate the errors caused by the formation and the subsequent
absorption of the oxides of nitrogen. Especially is this true
in determining the composition and the nature of organic sub-
stances of fundamental importance, compounds which serve
as the basis of new theories in organic chemistry. It is in
such instances that the vital importance of the greatest de-
gree of accuracy in organic analytical operations is apparent.

Owing, perhaps, to its technical importance, the determina-
tion of carbon has been brought to a state of perfection rarely
attained by the methods of analytical chemistry. The techni-
cal methods for the determination of carbon are, however, not
readily applicable in the analysis of organic compounds and.
furthermore, in most technical methods of analysis no provi-
sion is made for the determination of hydrogen ; but the de-
termination of hydrogen is of almost as great, if not of equal,
importance and the method most commonly used in the lab-
oratory for the determination of carbon, i. e., combustion with
cupric oxide in a current of air or oxygen, permits of the de-
termination of hydrogen.

The formation of oxides of nitrogen in the combustion of
organic substances containing nitrogen by the cupric oxide
method was first noted by Gay-Lussac' Nitrogen, while
ordinarily a most inert substance, unites at high temperatures
with the oxygen of the air to form nitric oxide. This phe-
nomenon is readily observed in all cases of combustion in air
where a high temperature is attained.

In the method of combustion adopted in the work here re-
ported the substance is first charred in the closed tube, /. e.,
with no current of air or oxygen, and, after complete charring,
oxygen is admitted to oxidize the non-volatile residue, and
the copper that has been reduced by the volatile products of
the dry distillation. As the oxygen is admitted the carbon
ignites and glows, and here it is true there may be a tempera-
ture sufl&ciently high to cause a union of the nitrogen in the
tube with the oxygen. That no appreciable quantities of

1 Ann. Chim., 95, 184 ; 96, 53.

336 Francis Gano Benedict.

oxides of nitrogen' are formed in this way, is seen by the fact
that they cannot be detected when non-nitrogenous organic
substances yielding carbonaceous residues are burned in a
current of air or oxygen.

In considering the formation of the oxides of nitrogen in the
combustion tube it is necessary to subdivide all organic nitro-
genous substances into two classes : one in which the nitro-
gen is attached to an oxygen atom, and the other ixi which
no oxygen is connected with the nitrogen. To the first class
belong nitro, nitroso, isonitroso, and azoxy bodies, oximes,
etc., while the second class includes practically all other
nitrogenous organic compounds : amines, amides, nitriles,
etc.

The bodies belonging to the first class would be expected
to yield oxides of nitrogen all the more readily as the nitrogen
is to a certain extent partially oxidized, and nitro compounds,
according to this assumption, owing to the high state of oxi-
dation of the nitrogen atom, would serve as types of the sub-
stances which would most readily liberate their nitrogen in the
oxidized form.

In the amido and other unoxidized nitrogen compounds on
the other hand, it would be necessary to have an actual oxi-
dation of the nitrogen atom to obtain oxides of nitrogen. In
an examination of the influence of the method of combustion
on the formation of the oxides of nitrogen it was found that
in burning urea, for example, in a current of oxygen, /. <?.,
without previous charring in the closed tube, the oxides of
nitrogen were formed to such an extent as to cause the pres-
ence of red fumes in the absorbing system. Obviously in this
case there was a direct oxidation of the nitrogen and at a
comparatively low temperature. Other amidic compounds
gave similar results.

In the absolute determination of nitrogen by mixing the
substance with finely pulverized cupric oxide and burning in
a vacuum, Klingemann^ found in the case of certain oxygen-
free azines and glyoxalines that very considerable quantities
of the oxides of nitrogen were formed. In this case the

1 The general term ' oxides of nitrogen' is applied to all products formed by the
reaction between nitric oxide, oxygen, and water.

2 Ber. d. chem. Ges., az, 3066.

Elementary Analysis of Orga7iic Substances. 337

nitrogen must have come from the compound and the oxygen
from the copper. Klingemann explains the formation of the
oxides of nitrogen as the action of the nascent nitrogen on the
copper oxide. It is interesting to note the evidence presented
by Klingemann to support the theory that the use of a copper
spiral in the regular carbon and hydrogen determination of
substances containing nitrogen is unnecessary.

O. F. Tower' has shown in an admirable treatment of the
subject that amidic nitrogen bodies, of which urea, hippuric
acid, and/-toluidine are taken as types, when burned in the
manner described on p. 335, yield no appreciable quantities
of oxides of nitrogen. Nitro bodies, such as dinitrobenzene
and nitraniline, also yield, according to his results, no oxides
of nitrogen. Trinitrophenol, on the other hand, liberates
sufficient quantities to affect materially the percentage of both
carbon and hydrogen.

In burning the amidic and " unoxidized nitrogen" com-
pounds in a closed tube, the combustion apparently proceeds
as follows : The substance, if not volatilized unchanged, un-
dergoes dry distillation, and the gases given off reduce the
first portions of the cupric oxide in the combustion tube. If
any oxides of nitrogen are formed, they are decomposed in
the presence of the reducing gases, the carbonaceous residue,
and the reduced copper. After dry distillation is complete,
the greater portion of the nitrogen is probably in the gaseous
form, though the charred residue may, according to some
writers, contain considerable quantities of nitrogen.

In volatile substances the combustion is practically all ac-
complished by the oxygen of the cupric oxide, though it is
possible that portions of the volatilized material, when passing
through the hot reduced copper, may be decomposed by the
heat with a deposition of carbon.

Nitro and allied bodies, on the other hand, yield, when
burned as above, nitric oxide in appreciable quantities. Ac-
cording to the investigations of Liebig,* Klingemann,' and
Tower,* nitric oxide is probably the only oxide of nitrogen

1 J. Am. Chem. Soc, 21, 596.

2 Pogg. Ann., 18, 357.

3 Ber. d. chem. Ges., 22, 3066.

4 J. Am. chem. Soc, 21, 596.

338 Francis Gano Benedict.

formed directly in the combustion of nitrogenous substances.
By means of secondary reactions with oxygen and water,
there may be formed almost any or all of the oxides of nitro-
gen, the chief of which is, however, nitrogen peroxide.

Nitric oxide itself would have no material influence on the
operation, for it is not absorbed by any of the reagents com-
monly used in this analytical process ; i. e. , concentrated sul-
phuric acid or fused calcium chloride for the absoiption of
water vapor, or concentrated potassium hydroxide solution or
soda-lime for the absorption of carbon dioxide.

Nitrogen peroxide, however, is always formed by the union
of nitric oxide with the oxygen in the tube or in the absorb-
ing system, and is absorbed by all the above reagents except
calcium chloride, thereby introducing the error.

In many cases the amount of oxides of nitrogen is not large,
and consequently is all retained by the sulphuric acid when
this reagent is used to absorb water, though in highly nitra-
ted bodies, especially those burning with explosive violence,
the percentage of carbon is often increased by the absorption
of the oxides of nitrogen in the carbon dioxide absorber.

A large number of combustions of oxidized and unoxidized
nitrogenous bodies were made to determine, if possible, the
cause of the variations in the amounts of the oxides of nitro-
gen. The anah^ses were made by first charring the material
in the closed tube ; i. e. , without the current of oxygen which
was finally admitted at the end of the combustion, each com-
bustion requiring about one hour for completion. The modi-
fied form of purifying apparatus and absorbing system de-
scribed in the preceding paper were used in all analyses.

Jena glass combustion tubes have given excellent satisfac-
tion, four tubes having withstood the heating in 97, 99, 104, and
116 combustions, respectively.

Table I gives a series of analyses of a number of pure sub-
stances burned with this method without the use of the cop-
per spiral, those of non-nitrogenous substances being added
for a dual purpose ; /. e., first to show the accuracy of the
method of analysis and second to show the purity of the prod-
ucts used in some subsequent operations.

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Elementary Analysis of Organic Stibstanccs. 341

An examination of the results of the table shows that with
the exception of the nitro bodies the percentages of hydrogen
and carbon, as a rule, are near the theory. The inability to
get perfectly pure oximes, azines, and glyoxyalines precluded
experimenting with those compounds. The specimen of uric
acid was found to contain 0.2 per cent of moisture and, if al-
lowance be made for this, the percentages of hydrogen and
carbon still more closely approach the theoretical.

In the case of dinitrobenzene the first discrepancy of any
magnitude is observed. Here the percentage of hydrogen is
invariably somewhat high, though the substance was found to
be perfectly anhydrous.

Great difiiculty was experienced in burning many of these
compounds, as on heating they decomposed readily, and at
times with explosive violence. It was found nearly impossi-
ble to obtain a regular combustion of picramide, picric acid,
or dinitronaphthol. This latter compound, while relatively
much less nitrated than either of the other two, gave off dense
red fumes, completely filling the combustion tube. Guani-
dine and urea nitrates, though yielding large quantities of
oxides of nitrogen, burned with great regularity.

While the oxides of nitrogen were, as a rule, wholly re-
tained by the sulphuric acid in the water-absorbing tube a
portion escaped into the carbon dioxide absorbers when trini-
trobenzene, dinitronaphthol, guanidine nitrate, and urea
nitrate were burned.

It thus appears that when burned as above described, com-
pounds containing " unoxidized nitrogen" yield no oxides of
nitrogen, at least none that is absorbed by sulphuric acid or
soda-lime. Compounds containing the nitro group, on the
other hand, do yield appreciable quantities of the oxides of
nitrog'.n, which are absorbed in sulphuric acid and soda-lime.
Nitraniline, though containing the nitro group, gave results
differing but little from theory, and it is this fact that led to the
method here described. Dinitrobenzene, when burned,
yielded nitric oxide, while when one nitro group is reduced
the resulting product, nitraniline, gave none. It appears,
therefore, that when there is sufficient reducing material, such
as carbon and hydrogen, in the molecule, and not too great a

342 Francis Gano Benedict.

proportion of nitro groups, the reducing material effects a re-
duction of the nitro group, and the nitrogen is then not re-
oxidized under the conditions of the combustion. Were a
large number of combustions of nitrated bodies made, it would
doubtless not be difl&cult to establish a relative proportion be-
tween the number of nitro groups and the carbon and hydro-
gen in the molecule necessary to effect the reduction of the
oxides of nitrogen.

It is evident, however, that the nitric acid molecule existing
in the two nitrates burned is not as readily reduced, for,
while nitroguanidine gave theoretical results, the nitrate con-
taining one more molecule of water yields large quantities of
the oxides of nitrogen. Nitroguanidine therefore contains
enough reducing material in its molecule to reduce completely
the nitro group. The nitric acid molecule of the two nitrates
is probably much more loosely combined and hence escapes
reduction.

In the ordinary methods of combustion, it is customary to
take some special precaution to eliminate any possible effect
of the oxides of nitrogen on the final results. These precau-
tions consist of one of two essentially different operations. In
one case the oxides formed are absorbed by lead peroxide,
manganese dioxide, potassium chromate, etc., or, more com-
monly, they are reduced by metallic copper and, in certain
special methods, by metallic silver.

The absorption of the oxides is almost always adapted to
special methods and is open to grave objections,

Gay-Iyussac,' in 1815, used hot metallic copper turnings to
reduce the oxides of nitrogen formed in the combustion of or-
ganic substances with cupric oxide, and this method is to-day
almost universally used. As ordinarily described, a 10 cen-
timeter length of cupric oxide is removed from the combus-
tion tube and a reduced spiral of copper wire or a roll of cop-
per gauze of the same length is inserted in the end of the
combustion tube to which the absorbing train is connected.
This operation is of itself time-consuming, but can be avoided
if two combustion tubes are held prepared, one with the cop-
per spiral and the other without it. Considerable difficulty

1 Ann. d. chim., 95, 184 ; 96, 53.

Elementary Analysis of Organic Substances. 343

has been experienced in satisfactorily reducing the copper
spiral. If hydrogen is used, the gas must be specially puri-
fied and, as Neumann' has shown, copper obstinately retains
material quantities of hydrogen which are later oxidized and
weighed as water. Reduction by means of methyl or ethjd
alcohol or formic acid has the advantage of being much
quicker and less laborious than that in which hydrogen is used,
but the copper retains the vapors of these bodies which are later
oxidized, and materially increase the percentage of both hy-
drogen and carbon. It is often recommended to dry out the
spiral in a current of hydrogen at a sufficiently high tempera-
ture to drive off the alcohol vapors, but in this operation con-
siderable hydrogen is occluded. In drying out the spiral re-
duced by alcohol in a current of carbon dioxide, it has been
found that enough carbon dioxide may be retained to vitiate
the results. The reduced spirals are often dried in air though
they are then rapidly coated with a superficial layer of copper
oxide, and their efficiency thereby much impaired. The most
satisfactory way is to allov/ the reduced spirals to remain a
number of hours in a vacuum desiccator though, as is readily
seen, this takes time, and a good vacuum desiccator is not
always at hand.

A further objection to the use of copper spirals is the fact
that, unless the air or oxygen is swept out of the combustion
tube, the spiral becomes somewhat oxidized on heating. It
is essential to replace the oxygen in the combustion tube with
air, an operation requiring a gasometer or other supply of air.

The method here reported is the outcome of an attempt to
secure a reduction of the copper with no danger of adding un-
known amounts of carbon dioxide and water to the materials
to be weighed. Those nitro compounds in whose molecule
there is a deficiency of carbon and hydrogen are burned with
an admixture of a known amount of a carbonaceous material
of known composition. In this way the carbonaceous material
including volatile gaseous products, and reduced copper, are
all in the position to react with any oxides of nitrogen formed
and effect their reduction.

The importance of pure materials cannot be overstated and

1 Monatshefte, 13, 40.

344 Francis Gano Benedict.

for the purposes of this research, sucrose in the form of well-
powdered rock-candy and Kahlbaum's pure benzoic acid, were
found to be very satisfactory.

In many of the analyses sucrose was used, though the re-
ducing material, the carbon (the hydrogen being theoretically
at least all oxidized) is but 42 per cent of the weight of the
substance. Benzoic acid and naphthalene are, weight for
weight, much more active as reducing agents than sucrose.
Nevertheless, in a large number of cases, the latter was used
with excellent results.

Sucrose of a remarkable degree of purity and dryness may
be obtained by pulverizing good crystals of rock candy after
carefully removing the strings. This material is not very
hygroscopic, and, unless the air is very moist, requires no
further precaution for its preservation than to be placed in a
well-stoppered bottle. In very damp weather, however, two
hours' drying, after pulverization, in the water- or air-bath at
not over 95°, will insure thorough dryness. All of the ma-
terial used in connection with the analyses here given was not
previously dried. As it was used in the analyses of sucrose
given in Table I, it is seen to be chemically pure. The su-
crose, owing to its purity, is always useful for check combus-
tions to test the accuracy of the method of combustion.

In general, it has been found desirable to place the sub-
stance in the boat in such a manner as to leave a free space
about a centimeter in length in the forward end. The greater
portion of the sucrose, benzoic acid, or naphthalene is placed
in this space and the remainder sprinkled over the top of the
layer of substance. The end of the boat containing the su-
crose is first inserted in the combustion tube, and the boat
pushed in till it nearly touches the asbestos plug holding the
layer of cupric oxide. The boat should not directly touch the
cupric oxide but be separated by a centimeter layer of air.
After heating the spiral in the anterior end of the tube, the
heat is brought toward the boat from the middle of the com-
bustion furnace ; hence the cupric oxide becomes thoroughly
heated before the end of the boat containing the reducing ma-
terial is heated. The sucrose melts at 143° and distils towards
200°, giving off empyreumatic vapors which reduce a portion

Elementary Analysis of Organic Substances. 345

of the contiguous cupric oxide, which becomes still more
heated as the flames are turned on. The melted sucrose often
mixes with or possibly partially dissolves the substance to be
burned, and when the sucrose finally chars there is a large
excess of carbon to aid in reducing the nitro group. Further-
more, the hot reduced copper may produce a decomposition of
the gases with a deposition of finely divided carbon.

When benzoic acid is used, the greater portion of the acid
is vaporized at a moderately low temperature, and no appre-
ciable quantity of carbonaceous residue is left. In this case,
therefore, the cupric oxide is reduced for a distance of several
centimeters, but no carbon is left to aid in reducing oxides of
nitrogen, save what may be formed on the hot reduced copper
by the decomposition of the benzoic acid vapor, which passes
over it. Hence it would appear that a carbonaceous residue
in the boat is not essential to the reduction of the oxides of
nitrogen.

When a new combustion tube is used, the presence of re-
duced copper is readily seen as a layer some 2 or 3 centime-
ters long in front of the boat, while the end of the rear cupric
oxide spiral inserted after the boat is always seen to be par-
tially reduced. Consequently there is a sufficient quantity of
metallic copper to reduce thoroughly the maximum amount
of oxides of nitrogen that can be formed.

Few nitro bodies are decomposed with an evolution of
oxides of nitrogen below the temperatures necessary to secure
the vaporization of benzoic acid or naphthalene or the dry
distillation of sucrose. It may be necessary, however, in some
cases to place the reducing material in a small copper boat a
little ahead of the porcelain boat containing the material to be
analyzed. In this case the copper could be reduced before
the material was heated.

One gram of pure sucrose, when completely oxidized, yields
1.5430 grams of carbon dioxide and 0.5791 gram of water.

One gram of pure benzoic acid, when completely oxidized,
yields 2.5235 grams of carbon dioxide and 0.4428 gram of
water.

One gram of pure naphthalene, when completely oxidized,

346 Francis Gano Benedict.

yields 3.4357 grams of carbon dioxide and 0.5627 gram of
water.

To determine the amount of carbon dioxide and water added
by reason of the combustion of the sugar or benzoic acid or
naphthalene, it is only necessary to multiply the weight of the
material used in grams by the factors for carbon dioxide and
water. The quantities of water and carbon dioxide calcula-
ted as being derived from the sucrose or benzoic acid used are
then subtracted from the actual weights found and the result-
ing weights used as in the regular method of calculation.

Table II shows the results of analyses of various nitre
bodies, using sucrose or benzoic acid to reduce the oxides
of nitrogen formed :

The results given therein indicate what may be expected
of the method, and it will be noticed that in all cases where
discrepancies appear the quantity of water actually weighed is
very small, and hence the error of weighing might, in many
cases, cause a discrepancy no smaller than those obtained.
The evidence, however, seems to indicate that no material,
absorbed by the sulphuric acid or soda-lime, other than water
and carbon dioxide, leaves the combustion tube.

Furthermore, as it is unnecessary to replace the oxygen left
in the tube by air, the necessity of a second gasometer is ob-
viated. Indeed, by this method one can make combustions
of nitrogenous or non-nitrogenous bodies with no change in
the manipulation other than the addition to the boat of a
known weight of pure sucrose or benzoic acid.

While sucrose and benzoic acid are here recommended as
reducing agents, many others may, of course, be used. Naph-
thalene suggests itself as the ideal substance, but it has been
a matter of considerable difficulty to obtain perfectly pure
naphthalene.

The explosive character of several of these compounds ren-
dered combustion very difficult. It was found, however, that
by mixing the finely powdered material with three or four
volumes of pure, ground quartz the combustions proceeded
with much greater regularity. Accordingly, many of the
combustions above tabulated were made with an admixture of
finely powdered silica. The silica contained no moisture and

Elementary Analysis of Organic Snbstances.

347

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348

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Francis Gano Benedict.

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Elementary Analysis of Organic Substances.

349

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350

Francis Gano Benedict.

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Elementary Analysis of Organic Substances.

351

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CO

0 'd-

NO

•-".a «

t^ LO

01

t^ 10

CN

04 NO

I/)

CO l^

NO

►H NO

10

co t--

10

^^0

I-I 0

d d
0

•s

N
C!
(U

t-i

d

d d
*a

cS
_o
'0

N

d

CO 0

d d

3
0

CU

'0

N
<U

d

CO 0

d d

3
0

C3
0
0

c

04

d

CO 0

d d
3

cd
0

"0

N
C
CU

04

d

CO 0

d d

3
'0

C3
0

*o

N
C

04

d

S-f-'S

+3

oi

+ .3

+.3

'5

+3

+3

."s

X 0 '^

0

?j^

0

rt
u

1^ J;^
0 "^

0

?^^

0

OJ

SJi

0

0 ^

0

CI

p C a

n

fl 0

J3

•i-i

G 0

c

G 0

f3

t:;

G 0

G

G a

a

i; oJ •;;;

rt

03 -r?

rt

C

rt •::?

n1

cj •:r

(T|

cj •-;

rrt

oj •:::;

01

§

.ti -^J 0

-(->

4-" 0

■M

-LJ 0

4->

+-. 0

r-f

-M 0

-M 0

■4->

S S2 N

W N

tn

rt

tfi N

-72

(fi N

J«

»-"

VI S!

w

tfl N

tn

^

S^ C

XJ

(u X3 n

^

X) c

^

rt

^ c

^

-Q c

^

»H g 1)

?i

d oj

D

u

a <u

3

j3 (U

•i

r^

G <L»

M

G lU

rs

Hcom

02

t/2pq

02

PclQPq

02

t/2 W

02

Oo2pq

02

02 w

02

352 Francis Gano Benedict.

apparently exercised no injurious effect on the combustion of
the material, for the percentages of carbon and hydrogen are
in almost every case well within the limits of error when the
quantity of material taken as well as its purity are considered.
Furthermore, numerous combustions of sucrose and benzoic
acid were made with a similar admixture of silica. In no case
was any discrepancy in the analyses obtained. The residue
remaining in the boat after the combustions was always per-
fectly white, indicating the absence of unoxidized material.

Singularly enough the admixture with silica has a direct
influence on the reduction of the oxides of nitrogen and, though
they are by no means completely reduced, they are present in
the products of combustion in much smaller quantities.

Table III.

Substance.

Weight
taken.

Weight
water
found.

Weight
carbon
dioxide
found.

Hydrogen. Carbon.
Found. Theory. Found. Theory.

Gram.

Gram.

Gram.

Per ct. Per ct. Per ct. Per ct.

Trinitrobenzene

0.2069

0.0293

0.2580

1.58 1.38 34.01 33.78

Trinitrophenol

0.2893

0.0409

0.3340

1.58 1.32 31.49 31.42

0.2791

0.0389

0.3228

1.56 ... 31.54 ....

0.2838

0.0373

0.3277

1.47 ... 31.49 ....

Trinitraniline

0.2877

0.0469

0.3316

1.87 1.77 31.46 31.55

0.2996

0.0502

0.3468

1-87 ••• 31-57 •♦••

In Table III several combustions of highly nitrated bodies
mixed with silica are given. It is seen that, while the per-
centages of hydrogen are still somewhat too high, the dis-
crepancies are not as great as when the combustion is made
of the material by itself, while the percentages of carbon are
sufficiently accurate for most purposes.

The materials used in this investigation were for the most
part of Kahlbaum's make, only those specimens showing
widest variation from the theoretical being obtained elsewhere.

My thanks are due to Mr. Emil Osterberg, assistant in this
laboratory, whose experimental skill has made the prosecu-
tion of this research possible.

The application of this method of reducing the oxides of
nitrogen to the absolute determination of nitrogen, by the
Dumas method, is to be investigated at an early date.

MiDDLETOWN, Conn.

Contribution from the Chemical Laboratory of the University of Utah.

AN APPARATUS FOR DETERMINING MOLECUIvAR

WEIGHTS BY THE BOILING-POINT

METHOD.

By Herbert N. McCoy.

The boiling-point method possesses two obvious natural ad-
vantages over the freezing-point method. In the former any
solvent may be used, while the latter is restricted to a compara-
tivel}' small number of solvents. At the boiling-point sub-
stances are, as a rule, much more soluble than at the freezing-
point. Nevertheless, as a means of determining molecular
weights, the freezing-point method has been very largely used
in preference to the boiling-point method. This has been
chiefly due to certain disadvantages attending the use of most
forms of apparatus designed for boiling-point determinations.

The rather long time required to attain a constant boiling-
point may lead to appreciable errors on account of intervening
barometric changes. Further, the weight of the solvent
placed in the boiling vessel does not represent the true weight
that is effective in forming the solution, as a fraction, indefi-
nite in amount, alwaj^s exists in the state of vapor. In most
forms of apparatus the cold liquid, formed by the condensa-
tion of this vapor, constantly drops back into the boiling
liquid, hindering greath' the establishment of equilibrium.
However, this latter disturbing influence is largely eliminated
in the forms of apparatus devised b}' Hite' and Jones. ^

The main difficulty has lain in obtaining regular boiling
without superheating. Numerous devices, such as glass
beads, garnets, balls of platinum gauze, and a platinum wire,
sealed into the glass, have been used, as is w^ell known, to
avoid this difficulty. While it is true that these have been
more or less successful in accomplishing the desired end, at
the same time the}^ have complicated the apparatus and made
the working of the methods more troublesome.

A distinct innovation was introduced by Sakurai,^ who

1 This Journal, 17, 514.

2 Ibid., 19, 5S.

» J. Chem. Soc, 61, 993.

354 McCoy.

prevented superheating and produced regular boiling by pass-
ing the vapor of the pure solvent into the liquid whose boil-
ing-point was to be measured, external heat being also ap-
plied.

Following up this advance, Landsberger has described a
method' by which many of the difficulties of the older boiling-
point methods have been overcome. The apparatus is sim-
ple. The process is very rapid, and the results ire fuU)^ as
good as those obtained by means of the elaborate apparatus of
Beckmann.^

According to lyandsberger's method a state of equilibrium
between the liquid and vapor phases is quickly attained by
substituting for the direct source of heat usually employed to
raise the liquid to its boiling-point, the latent heat of the
vapor of the pure solvent. The liquid whose boiling-point is
to be determined according to L,andsberger's method is con-
tained in a large test-tube, holding also the thermometer, and
surrounded also by a larger tube which serves as a jacket.
The vapor is generated in a flask by direct heat and is con-
ducted into the liquid in the inner tube, rapidl}^ bringing it to
its boiling-point. A hole in the side of the inner test-tube
near the cork allows the excess of vapor to pass into the jacket
and a side neck of the latter leads the uncondensed portion of
the vapor from the jacket to an ordinary condenser.

That a solution, even a saturated one, may be heated to its
boiling-point by the vapor of the pure solvent, has long been
known. It is obvious, however, that no superheating can
occur as the liquid and vapor can exist in contact at but one
definite temperature. No beads or garnets, etc., are required.
Thorough mixing of the liquid and vapor is insured. No cold
liquid runs back into the boiling vessel and radiation is largely
prevented by the jacket which is filled with hot vapor. Since
a determination can be made in half an hour, barometric
changes have little effect on the results.

Walker and L,umsden* have improved Landsberger' s ap-
paratus by using a graduated inner tube and measuring the
volume of the solution instead of weighing it ; a procedure

1 Ber. d. chem. Ges., 31, 45S.

2 Ztschr. phys. Chem., 8, 226.
» J. Chem. Soc, ^3, 502.

Apparatus for Determining Molecular Weights. 355

which Beckmann' has shown to be equally applicable. The
graduated tube allows a determination of the real volume of
the solution. This is preferable to a knowledge of the whole
amount of solvent present, part of which necessarily exists
as vapor at the time the boiling-point is measured, thus ren-
dering the solution more concentrated than the amount of
solvent weighed out would indicate. Of greater importance
is the fact that several determinations of the molecular weight
may be made with the same quantity of substance, by observ-
ing the boiling-point at different dilutions, the corresponding
volumes being read off on the graduated tube.
_ In the method just described the jacket must be kept filled
with vapor at the temperature of the boiling-point of the sol-
vent. To do this requires a more rapid current of vapor pass-
ing through the solution than would otherwise be necessary
to establish equilibrium between vapor and the solution.
Now, as the solution is heated solely by the latent heat of this
vapor, there is with some solvents, notably benzene, a rapid
condensation of the vapor in the inner tube. The condensa-
tion is greater the smaller the ratio of the latent heat to the
specific heat of the solvent employed. The dilution thus
caused soon increases the volume of the solution beyond the
capacity of the apparatus and so limits the number of dupli-
cate determinations to one or two.

In applying Walker and L,umsden's modification of I^ands-
berger's method, it occurred to me that the difiiculty just
mentioned would be remedied and other advantages would be
gained by combining the functions of the boiling-flask and the
jacket. As a result the apparatus shown in the figure has
been devised.^

The vessels A and B are of glass. The smaller one. A, in
which the thermometer is placed, is 20 cm. long and 2.7 cm.
wide. Its lower portion is graduated between the points
marking 10 cc. and 35 cc. It has a narrow tube ab, opening
to the exterior at a, 7.5 cm. from the open end. The tube ab
is closed at the lower end b and perforated with five small
holes. Another tube, ^,2.5 cm. from the mouth of A, leads
to a Iviebig's condenser C. The jacket B is 22 cm. long and

1 Ztschr.phys. Chem., 6, 472.

2 This apparatus may be obtained from EJimer & Am.end, New York.

356

McCoy.

4 cm. wide, excepting near the bottom where it is somewhat
enlarged. A short tube d, bent upward slightly, is attached
to the jacket about 7 cm. from the mouth. The tube d is
closed by a rubber tube and Mohr's pinch-clamp. A is held
in position by a cork fitting tightly into the jacket.

When a determination is to be made the apparatus is sup-

ported by a universal clamp and the tube c is connected with
a lyiebig's condenser. About 50 cc. of the pure solvent and a
small piece of clay tile are placed in the jacket and 12-16 cc.
of the solvent in the inner tube. The liquid in the jacket is
heated to boiling by a small flame, best protected from air
currents by a small iron chimney, such as is used in analytical
work. The bit of tile promotes regular boiling and the vapor

Apparatus for Determining Molecular Weights. 357

heats the liquid in the graduated tube nearly to its boiling-
point by contact with the outside of the inner tube. But as
soon as the liquid in the graduated tube has become hot, the
vapor rises in the jacket and forces its way through the tube
ab into the liquid in the graduated tube and brings it to its
boiling-point. Before this point is reached the liquid in the
jacket may be allowed to boil briskly, but now the heat is to
be adjusted so that the liquid in the inner tube boils slowly
but regularly, and a very slow distillation into the condenser
takes place.

When the thermometer is constant, or does not change more
than o.ooi of 1° in thirty seconds, the reading is taken as the
boiling-point of the pure solvent. This point is reached, as a
rule, in from five to ten minutes after the heating is com-
menced. The pinch-clamp closing the tube d is now re-
moved and then the flame is withdrawn. If the flame be
withdrawn before admitting air through d the liquid in the
inner tube runs over into the jacket through the tube ab.

The weighed substance, whose molecular weight is to be
determined, is now introduced by raising the stopper carrying
the thermometer, d is closed, and the solvent in the jacket
again boiled. If the substance dissolves readily, the solution
quickly reaches its boiling-point and the thermometer reading
becomes constant in a very short time. Usually only three or
four minutes elapse between the time of reading the boiling
point of the solvent and that of the solution. After the boil-
ing-point of the solution is taken the tube d is again opened
and the boiling stopped. The volume of the solution is read
at once, after lifting the thermometer out of the solution.

To obtain further readings at greater dilution, the thermome-
ter is replaced and a new determination of the boiling-point
made. The corresponding volume is read off as before. In
this way five, six, or even more determinations of the boiling"
point may be made with the same amount of substance.
Since, at each heating, some of the solvent will condense in
the inner tube, the volume of the solution will be a little
greater at each successive reading and the boiling-point of the
solution will decrease accordingly. The volume that con-
denses in the graduated tube at each heating is small. It is

358 McCoy.

greatest with benzene, where it amounts to only 2.5 cc. With
water the increase was but a few tenths of a cubic centimeter,
so that a little water was added each time in order to increase
the dilution by larger increments.

The molecular weight is calculated from the formula

where W is the weight of the substance, ^ the elevation of the
boiling-point, and V the volume of the solution. T is a con-
stant having a different value for each solvent. This formula
is very similar to that used when the weight of the solvent in-
stead of the volume of the solution is determined, the only
difference being the replacement of the factor representing
the weight by that indicating the volume. The values of T
in the above formula are obtained from the corresponding
values for the old formula by dividing the latter by the specific
gravity of the solvent at its boiling-point.

The following are the values of T for a few common sol-
vents :'

Alcohol 1560 Carbon bisulphide 1940

Ether 3030 Acetone > 2220

Chloroform 2600 Aniline 3820

Benzene 3280 Water 540

The apparatus has been tested by determining the molecu-
lar weight of a number of substances, using four different sol-
vents. The results have been very satisfactory. No tedious
and troublesome precautions seem to be necessary to obtain
fairly good results and the time required is very much less
than is needed for a determination with the Beckmann appara-
tus. Frequently the apparatus has been set up, the substance
weighed out, and a determination made at two dilutions in
less than thirty minutes.

In the determinations here recorded the weighings were
made on a simple balance, sensitive to milligrams, and the
Beckmann differential thermometer was read by means of a
hand lens. The substances whose molecular weights were
determined were the so-called chemically pure preparations of

1 Beckmann : Ztschr. phys. Chem., 6, 472.

Apparatus for Determining Molecular Weights. 359

C. A. F. Kahlbaum not further purified. The alcohol used
was Kahlbaum's absolute, treated with anhydrous copper sul-
phate. The benzene was Kahlbaum's thiophene-free prepa-
ration, made from benzoic acid. It was dried with metallic
sodium. The ether was of good quality. It was washed
many times with water, dried with calcium chloride, and dis-
tilled over metallic sodium. The determinations were not
made with the object of attaining the greatest possible accu-
racy, but rather to test the value of the apparatus for practical
use in ordinary organic research. In the last column the
values found by Beckmann, at about the same concentration,
are given for comparison.

Weight of
substance.

0.806

I.OIO

SOLVENT, alcohol; t= 1560.
Naphthalene, 128.

Volume of
solution.

28.0

29.0

Elevation of Molecular Beckmann
boiling-point, weight found. found.

0.291
0.278

Benzoic Acid, 122.

24.2
25-3

0.535
0.519

154
156

122
120

Salicylic Acid, ij8.

0.995 24.1 0.452 142

25.3 0.435 141

Benzanilid, igy.

0.626 15.2 0.299 215

" 17.9 0.262 208

155

124

140

Weight of
substance.

0.950

0.985
1. 000

SOLVENT, BENZENE ; T — 3280.
Benzil, 210.

Volume of Elevation of Molecular Beckmann
solution. boiling-point, weight found. found.

19-3
21.8

0.670
0.570

Salicylic Acid, ij8.

22.5
24.0

0.549
0.538

241
250

261
256

230
236

234

36o

0.981

McCoy.
Naphthalene, 128.

19. 1
21.6

1. 301
1. 141

130
131

SOI.VENT, ETHER ; T = 3030.
Naphthalene , 128.

144

Weight of
substance.

Volume of
solution.

Elevation of
boiling-point.

Molecular
weight found.

iJeckmann
found.

1.025

16.0

1.498

130

132

SOLVENT, WATER ; T = 540.

Boric Acid, 62

Weight of

Volume of

Elevation of

Molecular

Beckmann

substance.

solution.

boiling-point.

weight found.

found.

1. 015

27-3

0.309

65.0

66.8

< (

28.6

0.297

64.5

( (

3I-I

0.282

62.5

((

33 4

0.262

62.6

( <

36.0

0.247

61.7

1.030

29.0

0.297

Urea, 60.

64.5

1.203

18.2

0.542

66.2

73

21.2

0.465

66.3

23.1

0-439

64.4

25-4

0.396

64.9

28.0

0.358

65.2

30.4

0.343

62.7

35.0

0.293

63.7

72

Maniiite, 180.

2.044

18.8

0.294

199

( (

22. »•

0.254

190

192

1 (

25.0

0.233

183

( 1

30.5

0.200

181

Salt I^ake City, J

an. 29, 1900.

REVIEWS.

Elementary Chemistry. For High Schools and Academies. By
Albert L. Arey, C.E., Rochester, New York, High School. New
York : Macmillan & Co. London : Macmillan & Co. 1899.

The thought that has guided the author in the prepara-
tiou of this book is expressed in his own words, thus: " It
was decided to omit all reference to those properties of the
substances studied in the laboratory, which can be learned by
observation of the substances themselves ; to render the work
more complete than it would otherwise be by stating such
properties as cannot be shown by experiments adapted to sec-
ondary schools." This assumes that the pupil at the outset
is capable of making good observations. This does not ac-
cord with experience. It is the object of a laboratory course
to train these powers of observation. It would certainly be
interesting to read the note-books of pupils who, without di-
rections from the teacher, should record the results of their
first observations on chemical substances. Of course, the
pupil should be led to use his own eyes and his own mind as
much as possible, but it is only with the aid of a thoroughly
conscientious teacher, who sees the needs of the pupil, that
this power can be developed.

On page 4 an extremely dangerous experiment is described,
thus : " Sulfur and potassium chlorate are mixed in a mortar
with considerable friction," What the results would be of
attempts by inexperienced persons to perform this experiment
the writer of this notice shudders to think. Not a word of
caution is given. It is all very well to say that this is an ex-
periment to be performed by the instructor, but many instruc-
tors in chemistry have had very little experience, and they
are as likely to go astray as the average pupil.

On page 5 are found directions for an experiment which is
not clear, though it sounds learned. The pupil is directed to
weigh a quantity of sulphuric acid and a solution of calcium
chloride ; then to pour them together and weigh the two
vessels again. The pupil is then askeH : " Does chemical ac-
tion change the total quantity of matte, in existence ? Was
the total quantity of sulphuric acid in the world increased or
diminished by the above experiment ? How was the total
quantity of calcium chloride affected?" As a matter of fact,
the total quantity of sulphuric acid in the world is diminished
by such an experiment, but the pupil cannot possibly know
this unless told. In the next question the pupil is asked to
state his opinion as to why solution aids chemical action. If

362 Reviews.

the pupil ventures to express an opinion at this stage of his
work he ought to be reprimanded very promptly.

Instances of this kind are frequent throughout the book and
are characteristic of it. They show clearly that the writer of
the book is not a well-trained chemist. He may be an excel-
lent teacher, but he has not shown that he is by the book that
he has written ; and this book, in the hands of inexperienced
teachers, would not be helpful. An experienced teacher, on
the other hand, might detect these defects, but it would be
necessary for him to be on the alert at every stage. i. r.

Victor von Richter's Organic Chemistry, or Chemistry of the
Carbon Compounds. Edited by Prok. R. Anschutz, University of
Bonn (Assisted by Dr. G. Schroetter). Authorized translation by
Edgar F. Smith, Professor of Chemistry, University of Pennsylva-
nia. Third American from the Eighth German Edition. Volume
II. Carbocyclic and Heterocyclic Series. Philadelphia: P. Blakis-
ton's Son & Co., 1012 Walnut St. 1900. pp. 671-f-xvi. Price, fe.oo.

Ivast 3^ear attention was called to the first volume of this
book that had then just been published. Now we have pre-
sented the " aromatic " and related compounds, or the " car-
bocyclic and heterocyclic series." The book has been so
long known and so favorably known that comments upon it
are superfluous. The work of editing and of translating has
been in most competent hands, so that we may be sure that
no pains have been spared to bring it up-to-date in every
respect. As remarked in the earlier notice, it is not adapted
to the u.se of the beginner, who would surely be drowned if
he should plunge in or even wade in too far. It is a shorter
book of reference, a good thing to have on the study table,
whether the table belongs to a student or a teacher. It is
not, of course, a substitute for Beilstein — nothing could play
that part successfully — but still it will be found helpful in
many cases if Beilstein is lacking or if completeness is not
aimed at. It is condensed to an extent rarelj^ met with, and
to such an extent as to make it hard to follow in places.
Take, for example, the treatment of the " Constitution of the
Benzene Nucleus," which covers not quite two pages of
small type. All that is said is no doubt correct, but either
the reader must understand the subject beforehand, or his
efforts to find out what this means will surely end in a bad
headache. It may, however, serve a useful purpose as
a reminder to the old stager. i. R.

Vol. XXIII. May, 1900. No. 5.

AMERICAN

Chemical Journal

PREPARATION AND PROPERTIES OF THE SO-
CAEI.ED "NITROGEN IODIDE."

By F. D. Chattaway akd K. J. P. Orton.

Nitrogen iodide was originally obtained by Courtois' in
181 3 by the direct action of ammonia on solid iodine. Solu-
tions of iodine in alcohol, chloroform, carbon tetrachloride, or
aqueous potassium iodide were substituted for solid iodine by
later observers, and both alcoholic and aqueous solutions of
ammonia have been employed. In all cases a black or dark-
brown amorphous solution was obtained.

Serullas^ prepared the substance by the interaction of iodine
monochloride and a solution of ammonia, a method which was
afterwards employed by Bunsen\ We have prepared nitro-
trogen iodide by these various methods, and have compared
the products which we find to be identical when proper pre-
cautions are taken to ensure the removal of all free iodine and
ammonia and to prevent decomposition.

Whenever iodine itself is used, whether in solution or as a
solid, less than half appears as nitrogen iodide. Exact ex-
periments showed that at ordinary laboratory temperatures the
nitrogen iodide formed contains about 47.5 per cent of the
iodine used. Of the remainder 51.6 per cent appears as am-
monium iodide and 0.8 per cent as ammonium iodate.

1 Ann. Chim., 88, 304.

2 Ann. chim. phys. [2], 22, 172 (1825) ; and 42, 200 (1829).
S Ann. Chem. (Liebig), 84, 1 (1852).

364 Chattaway and Orton.

The use of alcoholic solutions of iodine or ammonia de-
creases largely the yield because the nitrogen iodide reacts
rapidl}' with the alcohol to form iodoform, which, moreover,
can never be wholly removed from the product. Bunsen,
however, used this method and obtained a substance,
analysis of which led him to the formula N2H3I3 for nitrogen
iodide. All our analyses of nitrogen iodide prepared in
various ways agree absolutely with this formula.'

Preparation of Nitrogen Iodide by the Action of Iodine Mono-
chloride on a Solution of Ammonia.

When iodine monochloride is used, 95 per cent of the
iodine appears as nitrogen iodide. The remainder is con-
verted into ammonium iodide and iodate, while the chlorine
appears as ammonium chloride. We have carefully investi-
gated this method and consider it the most suitable for pre-
paring pure nitrogen iodide in large quantities. The best
procedure for the preparation of the iodine monochloride and
of the nitrogen iodide is as follows :

One hundred grams of finely powdered iodine are placed in
300 cc. of hydrochloric acid of sp. gr. 1. 15 in a porcelain basin
and 28 cc. of nitric acid of sp. gr. 1.41 are added. This
quantity of nitric acid provides just, sufficient chlorine to con-
vert the iodine into iodine monochloride. The mixture is
warmed on a water- bath to about 40° and continuously stirred,
the beginning of the reaction being marked by the color of
the liquid changing from brown to pale-yellow. The iodine
gradually dissolves and the solution becomes orange in color.
If the mixture be well stirred and the temperature not allowed
to rise above 40°, no chlorine escapes. After the whole of the
iodine has dissolved, the water in the bath is boiled for some
time in order to expel the nitrosyl chloride. With the excess
of hydrochloric acid used, the solution of iodine monochloride
is perfectly stable and undergoes no decomposition even when
boiled. To prepare nitrogen iodide it is cooled and diluted
by adding about three times its bulk of crushed ice.

For every 10 grams of iodine 100 cc. of strong commercial

^ Bunsen determines the relation of nitrogen to iodine only, and in his method of
analysis any trace of iodoform present would not cause error.

Nitrogen Iodide. 365

ammonia (sp. gr. 0.880) are poured over about three times
their weight of crushed ice and the cold solution of iodine
monochloride slowly run in, the mixture being vigorously
stirred during the addition.' The black precipitate of nitro-
gen iodide which at once separates, is filtered off by a pump
through asbestos and washed with dilute ammonia, and
finally, if required free from ammonia, three or four times
with water. In this way a kilogram of nitrogen iodide can
be obtained as a compact cake with perfect safety. It is best,
if possible, to leave the solid mass damp with strong ammonia,
for then filter-paper can be used instead of asbestos, and the
slight decompositions which take place in the total absence of
ammonia, and may give rise to local explosions, is prevented.'

Preparation of Crystalline Nitrogen Iodide.

In the course of this investigation it became obvious that
nitrogen iodide is not formed by a direct substitution of
iodine for hydrogen in ammonia, but that the iodine reacts
with ammonium hydroxide as with other alkalies to form am-
monium iodide and hypoiodite, and that the latter then de-
composes, forming nitrogen iodide. This view was originally
offered by Schonbeiu^ as a suggestion, which has been en-
dorsed by Seliwanow.* The addition of ammonia to an alka-
line solution of potassium hypoiodite should, therefore, lead
to the formation of NH^OI, ammonium hypoiodite, which
should then decompose, producing nitrogen iodide. This we
have found to be the case ; and, further, under certain condi-
tions of concentration the nitrogen iodide separates in a crys-
talline form.

The following method gives good results : A decinormal
solution of iodine monochloride is prepared by diluting with
water to i liter a solution of iodine monochloride, ICl, made
as above, from 12.7 grams of iodine. This dilute solution is

1 The solution of ammonia should not be added to the solution of iodine mono-
chloride, for then iodine is liberated and the yield much reduced.

2 Andre (Jour. Pharm., 32, 137 (1836)) obtained nitrogen iodide by the addition of
ammonia to a solution of iodic acid in hydrochloric acid. Such a solution contains
iodine monochloride after it has been heated, for, as is well known, iodic and hydro-
chloric acids then react according to the equation : HIO3 -|- 5HCI = ICl -f- aClj -|-3H,0.

« J. prakt. Chem., 84, 385 (i86j).
* Ber. d. chem. Ges., 27, 1012 (1S94).

366 Chattaway and Orton.

unstable and should only be prepared immediately before use.
Fifteen cc. of this solution are added to 100 cc. of a half-nor-
mal solution of potassium hydroxide (3 percent), and then, as
rapidly as possible, 10 cc. of ammonia (sp. gr. 0.880) are run
in while the solution is gently shaken. The pale-yellow
liquid remains clear for a short time, but within a minute
glittering copper-colored crystals of nitrogen iodide begin to
separate, and after a few minutes the crystalliz?tion is com-
plete. The yield is satisfactory, being from 65-70 grams per
100 grams of iodine. When larger quantities than those indi-
cated are used the yield is not so good owing to the difl&culty
of mixing the solutions sufl&ciently rapidly. Under the micro-
scope very minute needles first become visible, which steadily
grow to the usual crystals. The large excess of potassium
hydroxide used prevents any setting free of iodine when the
acid solution of iodine monochloride is added to it. If more
than 15 cc. of y^ be added to loo cc. -f-, the crystals separate
more rapidly and are smaller. With further increased con-
centration the crystals become mixed with amorphous nitro-
gen iodide, which finally forms the chief product.

Replacement of ammonia by a dilute solution of an ammo-
nium salt also causes a deposition of crystalline nitrogen
iodide, if the ammonium salt be added very cautiously. An
amorphous precipitate is obtained if the solution of ammonium
salt be added rapidly or if it be concentrated.

Amorphous nitrogen iodide can be converted into the crj^s-
talline variety by an apparent recrystallizatiou from a hot
solution of ammonia. The conversion is, however, really due
to the occurrence of a reversible reaction in the system (nitro-
gen iodide -|- ammonium hypoiodite-j- ammonium hydroxide) .
In this system, at the state of equilibrium, the concentration
of ammonium hypoiodite is greater at a high than at a low tem-
perature with a given concentration of ammonia. To obtain
crystalline nitrogen iodide by this method about 0.5 gram of
the amorphous substance is heated with 100 cc. of thrice-nor-
mal ammonia solution, in which it partially dissolves, produ-
cing a pale-yellow solution, and this, after filtration through
asbestos, deposits crystals when rapidly cooled. With larger
quantities the time required to cool the bulk of hot liquid

Nitrogen Iodide. 367

leads to the conversion of so large a proportion of the ammo-
nium hypoiodite into iodate and iodide that little nitrogen
iodide separates.

Crj'stals can also be obtained by the direct addition of a
solution of iodine monochloride to ammonia. For this pur-
pose the solution of ICl must be about one-fiftieth normal and
must be added very slowly to a fairly concentrated solution of
ammonia.'

Properties of Nitrogeyi Iodide.

Crystals of nitrogen iodide suspended in water look like
splinters of burnished copper, and when dry have a ruby-red
color and a fine luster. Ordinary amorphous nitrogen iodide
shows no trace of crystalline structure and appears quite black
when suspended in water, but if filtered off and dried is seen
somewhat to resemble the crystalline substance in color.

Pure nitrogen iodide is without effect on a neutral solution
of litmus and gives no reaction of iodine when shaken with
chloroform. In contact with water it soon shows signs of de-
composition, the amorphous more rapidly than the crystalline
variety. The crystals lose their lustre and under the micro-
scope are seen to be etched and corroded. Too prolonged
washing with water on the filter will cause this decomposition
to take place. Free iodine is then always found by the chloro-
form test in the solid residue while free ammonia can be de-
tected in the filtrate."

Nitrogen iodide can be dried over lime or baryta in an at-
mosphere of ammonia, if light be absolutely excluded, with-
out any decomposition taking place. When dry it can be
safely detached from a porous tile with a spatula, but slight
percussion, pressure between hard surfaces, or rapid heating

1 The formation of nitrogen iodide has been observed in the action of bleaching
powder on a solution of ammonium iodide. [Playfair in discussion on Gladstone's
paper (Chem. Soc. J., 4, 34 (1852)]. In this case undoubtedly ammonium hypoiodite
is first produced and from it the nitrogen iodide is formed. The product separating
is always mixed with calcium iodate, which can only with difficulty be removed by
prolonged washing with ammonia. In the electrolysis of an ammoniacal solution of
potassium iodide t,osanitsch and Jowitschitsch (Ber. d. chem. Ges., 29, 2430) noticed
that at the positive pole nitrogen iodide was deposited and that hypoiodite could be
recognized in the solution.

2 Pure nitrogen iodide consequently cannot be obtained, as many observers have
stated, by washing the product until the filtrate becomes neutral.

368 Chatiaway and Orion.

cause it to detonate with violence. The whole mass explodes
at once without scattering, but the explosion is never com-
municated to any of the substance lying only a few centime-
ters away. A puff of violet vapor surrounded by a cloud of
white fumes is seen, and in a dark room a green flash of light
is noticed, resembling in color the flame of burning ammonia.
Nitrogen iodide is remarkably sensitive to light. Bubbles of
nitrogen are slowly given off in diffused light from the com-
pound suspended in water while in direct sunlight rapid effer-
vescence takes place. The dry substance in diffused light be-
comes gradually covered with minute crystals of iodine, which
appear more quickly and grow more rapidly in sunlight.

Partially decomposed nitrogen iodide is very unstable and
explodes at the slightest touch.

The following description of the crystals of nitrogen iodide
has been given us by Mr. W. J. Pope, who very kindly un-
dertook their examination : The crystals are small, flattened
needles of a bright ruby color in transmitted light. The ex-
tinction through all faces in the zone of the long edge is
straight and the crystals are probably orthorhombic ; the
forms would then be jooi \ . \ 101 \ and 1 noj and the crystals
are lengthened in the direction of the axis b. The plane an-
gle between the edges 001 : loi and 001 : no is 140° and
very frequently only one face of | noj is present at one end.
An optic axis can be sometimes just discerned at the edge of
the field, emerging in the plane )oio| .

The crystals are dichroic. On looking through \ 001 1 using
light polarized in the plane ) 100 1 light of a beetle-green color
is transmitted, but if the plane of polarization be |oio| light
of a ruby-red color comes through.

The specific gravity of crystalline nitrogen iodide is about
3.5. This number has been obtained by drying a quantity of
the substance in an atmosphere of ammonia in a specific grav-
ity bottle and weighing it first in air and then under water.

Chkmical Laboratory, St. Bar-
tholomew's Hospital and
College, London.

THE ACTION OF REDUCING AGENTS UPON
NITROGEN IODIDE.

By F. D. Chattaway and H. P. Stevens.

All ordinary reducing agents when brought into contact
with nitrogen iodide, suspended in water, rapidly decompose
it. In these reactions the different reducing agents are in-
variably oxidized while hydriodic acid and ammonia are pro-
duced. The quantity of reducing agent oxidized is found in
every case to be exactl}- double the amount equivalent to the
hydriodic acid produced, using nitrogen iodide obtained by
any method. The action of sodium sulphite, sulphurous
acid, arsenious oxide, antimonious oxide, stannous chloride,
and hydrogen sulphide has been investigated with the fol-
lowing results :

Amount of reducing

agent oxidized Na.SO, H.SO, As,S, Sb,03 SnCl, H,S

Amount of hydriodic
acid simultaneous-
ly produced HI HI 2HI 2HI HI HI

All the iodine contained in nitrogen iodide, therefore, be-
haves towards reducing agents like the chlorine contained in
a hypochlorite and exerts twice its normal oxidizing action.

Action of Sodium Sulphite on Nitrogen Iodide.

When a solution of sodium sulphite in excess is added to
nitrogen iodide suspended in water, rapid interaction ensues
and a colorless solution, somewhat acid from the presence of
hydriodic acid, results.

If the sulphite be added slowly from a burette a liquid col-
ored brown by free iodine is obtained when the solid has en-
tirely disappeared ; the end-point of the reaction is then easily
seen by the disappearance of the color, or starch paste may be
used as an indicator. The hydriodic acid produced can after-
wards be estimated in one of several ways ; the most conve-
nient and the one usually adopted is to titrate the clear solu-
tion with standard silver nitrate, using the blue so-called
" iodide of starch" as indicator.' The actual operation iscar-

1 Pisani : Annal. d. Min., lo, 83.

37© Chatiaway and Stevens.

ried out as follows : Nitrogen iodide prepared in any one of
the ways previously described is rapidly filtered off through
asbestos by the aid of a pump, and thoroughly washed with
decinormal ammonia, and finally once with water. A num-
ber of 250 cc. flasks having been prepared, about 0.2-0.5
gram of the moist iodide is placed in each with about 25 cc.
of water, and titrated as rapidly as possible with decinormal
sodium sulphite, shaking gently the wdiile. The estimation
of hydriodic acid by silver nitrate is then carried out in the
ordinary way. Light must be rigorously excluded while
washing and transferring the nitrogen iodide to the flask and
during the titration until all solid particles have disappeared.

In the tables where the results are recorded the amount of
reducing agent oxidized is stated in the second line, that of
the hydriodic acid produced in the third, while in the fourth
is the ratio betw-een the reducing agent oxidized and
the hydriodic acid produced, calculated to the third decinor-
mal place.

The Roman numerals in the first column refer to the mode in
which the nitrogen iodide used was prepared. The experi-
ments numbered I were made with amorphous nitrogen iodide
prepared by adding a decinormal solution of iodine in potas-
sium iodide to a strong solution of ammonia ; those marked
II with material prepared similarly but using a normal solu-
tion of iodine. In those numbered III the nitrogen iodide
was made by treating finely powdered iodine with a strong
solution of ammonia ; in those numbered IV iodine, precipi-
tated by diluting a saturated solution of iodine in potassium
iodide, was used. In preparing the material for those num-
bered V an alcoholic solution of iodine,' and for those marked
VI a solution of iodine monochloride was added to a satura-
ted solution of ammonia. In experiments VII and VIII
crystalline nitrogen iodide was employed, prepared respec-
tively by adding ammonium hydroxide to a solution of potas-
sium hypoiodite and hy heating amorphous nitrogen iodide
with ammonia and rapidly cooling. In those numbered IX the
nitrogen iodide was prepared by adding an excess of a solu-
tion of bleaching powder to a solution of ammonium iodide.

1 In these cases a small residue of iodoform was left in the flask after titration.

Nitrogen Iodide. 371

Although in the tables one result only with each specimen
of nitrogen iodide is given, this has in every case been con-
firmed by from 22 to 30 concordant experiments :

N NajSOj

Number of

10 a

T^'oHI

experiment.

oxidized,
cc.

produced,
cc.

Ratio.

I

87.1

43-6

2

: 1. 001

II

68.2

34-1

2

: I

III

47.1

23.6

2

: 1.002

IV

70.5

35-3

2

: 1. 001

V

86.2

43.2

2

: 1.002

VI

138.2

69.1

2

: I

VII

60.8

30.4

2

: I

VIII

98.1

49.1

2

: I. 001

IX

80.7

40-3

2

: 0.999

In order to establish beyond question this ratio between the
sodium sulphite oxidized and the hydriodic acid produced,
series of experiments have been made in which the latter was
estimated by other methods.

In the following series, after the decomposition of sodium
sulphite, the hydriodic acid was oxidized by iron-alum and
sulphuric acid, and the liberated iodine distilled off and titra-
ted by the same sulphite solution. The distillation was car-
ried out in a special form of apparatus,' in which only ground
glass joints are employed, and to prevent bumping, a very
slow stream of carbon dioxide is led in by a capillary tube to
the bottom of the boiling liquid :

N NajSOs N Na^SOj

Number of
experiment.

10 2

oxidized by

nitrogen

iodide

used.

10 2

oxidized hy iodine
liberated from

hydriodic
acid produced.

Ratio.

cc.

cc.

I

46

23

2 : I

II

42.1

21. 1

2 : 1.002

III

52.7

26.3

2 : 0.998

IV

65.6

32.7

2 : 0.997

V

45

22.5

2 : I

VI

48.6

24-3

2 : I

Exactly similar results were obtained when the hydriodic
acid formed was estimated by adding an excess of silver nitrate

1 Ghem. News, 1899, 85.

372 Chattaway and Stevens.

and then determining the excess by a standard solution of
potassium thiocyanate.

In connection with the action of reducing agents a number
of experiments were made to show the necessity for the ex-
clusion even of the diffused light of a laboratory when work-
ing with nitrogen iodide. Some amorphous nitrogen iodide
prepared by adding a solution of iodine monochloride to am-
monia was taken and carefully washed with decinormal am-
monia. Approximately equal quantities were then placed in
4 flasks ; that in flask A was titrated immediately with sodium
sulphite ; that in flask B was exposed to the diffused light of
the laboratory on a dull winter afternoon for five minutes and
then titrated ; that in Cwas similarly exposed for ten minutes;
that in D for twenty minutes. The hydriodic acid formed in
each case was afterwards estimated by silver nitrate, and the
ratio calculated between this and the sulphite oxidized.

N Na^SOa

T^o HI

present. Ratio,

cc.

37.4 2 : I

39.2 2 : I. 100

38.2 2 : I. 17

49.1 2 : 1.34

It is seen that the ratio diminishes as the time of exposure
increases. This is due to a decomposition of some of the nitro-
gen iodide into nitrogen and hydriodic acid, a change which
occurs whenever the substance is exposed to light.

A solution of sulphurous acid behaves toward nitrogen
iodide as sodium sulphite does; a further action, however, ac-
companies this, similar to the one occurring when nitrogen
iodide is exposed to light, whereby a small portion breaks up
into nitrogen and hydriodic acid. This latter, as it is esti-
mated with that produced by the reducing agent, causes the
ratio to appear too low. If, however, the amount due to the
reaction with the sulphurous acid be calculated from the am-
monia formed, as can easily be done when the composition of
the substance is known, the quantity of sulphurous acid oxi-
dized is found to be exactly double that equivalent to the
hydriodic acid produced.

Number

of

10 2

experiment.

oxidized.

cc.

A

74.8

B

71-5

C

65

D

73-2

Nitrogen Iodide. 373

Action of Arsenious Oxide on Nitrogen Iodide.
When a solution of arsenious oxide is slowly added to nitro-
gen iodide suspended in excess of a solution of sodium bicar-
bonate until the particles disappear, ammonia, arsenic acid,
and hydriodic acid are produced, and the amount of arsenious
acid oxidized is found to be exactly double that which is
equivalent to the hydriodic acid formed. The experiments
were carried out much as before, the hydriodic acid, however,
being estimated by making the liquid acid, adding silver
nitrate in slight excess, and estimating the excess added by
potassium thiocyanate,

N AS5O3

Number of

10 4

tI.hi

experiment.

oxidized,
cc.

produced,
cc.

Ratio.

I

42.3

21. 1

2

: 0.997

II

45-9

22.9

2

: 0.997

III

37-9

18.9

2

: 0.997

IV

44-5

22.3

2

: 1.002

VI

43-8

21.9

2

: I

VII

33.2

16.6

2

: I

Similar results were obtained when the hydriodic acid was
estimated by determining the amount of a standard solution of
potassium permanganate required to oxidize it to iodic acid.

Action of Antimonious Oxide on Nitrogen Iodide.
The action of antimonious oxide on nitrogen iodide is ex-
actly similar to that of arsenious oxide, the compound being
converted into the higher oxide, while ammonia and hydriodic
acid are produced. Similarly the quantity oxidized is double
the amount equivalent to the hydriodic acid formed. The
experiments were carried out as with arsenious oxide, a deci-
normal solution of tartar emetic being used and sodium bicar-
bonate added in larger excess.

N SbaOg

Number of

10 4

TO HI

experiment.

oxidized,
cc.

produced,
cc.

Ratio.

I

31-3

15-7

2

: 1.003

II

39-4

19.8

2

: 1.005

III

32.6

16.4

2

: 1.006

IV

26.1

I3-I

2

: 1.003

VI

38.2

19.1

2

: I

VII

34.7

17.4

2

: 1.002

ex;

374 Chattaway and Stevens.

Action of Stannous Chloride upon Nitrogen Iodide.

Stannous chloride, dissolved in the least possible quantity
of dilute hydrochloric acid, readily reacts with nitrogen iodide,
and if it be added slowly a little iodine is liberated. If the
addition be continued till this liberated iodine just disappears,
stannic chloride, ammonium chloride, and hydriodic acid alone
are formed. The latter can be estimated by converting it
into iodic acid by a solution of potassium permarganate, the
ammonium being first expelled by a slight excess of caustic
soda. The quantity of hydriodic acid formed is found to be
half the amount equivalent to the stannous chloride oxidized.

Number of xo SnClz x7 -^^

experiment. oxidized. produced. Ratio.

cc. cc.

I 32.5 16.6 2 : 1.009

II 31.4 15.8 2 : 1.006

III 40.2 20.1 2:1

IV 30.7 15.5 2 : 1.009

VI 30. r 15. 1 2 : 1.003

VII 27.9 14 2 : 1.003

The ratio usually comes out slightl}'- too high. This, as in
the case of sulphurous acid, is due to a small quantity of the
nitrogen iodide breaking down into nitrogen and hydriodic
acid under the influence of the hydrochloric acid which must
be present to keep the stannous chloride in solution.

Action of Hydrogen Sulphide 071 Nitrogen Iodide.

On a solution of hydrogen sulphide being added to nitrogen
iodide suspended in water the solid particles rapidly disap-
pear, sulphur is precipitated, and ammonia and hydriodic
acid are produced as in other cases. If the solution of hydro-
gen sulphide be very slowly added, iodine is set free, and the
end of the reaction can be recognized easily by its disappear-
ance. The investigation of this action is complicated by the
circumstance that during it a considerable portion of the
nitrogen iodide decomposes into nitrogen and hydriodic acid,
and thus the ratio between the hydrogen sulphide oxidized
and the hydriodic acid produced appears too great if the lat-
ter is directly estimated.

Nitrogen Iodide. 375

The following estimations show that the ratio thus obtained
is variable but approximately 2 : 1.2.' The hydriodic acid
was determined by adding a small excess of silver nitrate and
estimating this excess by potassium thiocyanate.

Number of

10 2

tVhi

experiment.

oxidized.

produced.

Ratio.

cc.

cc.

I

28.4

16.7

2 : 1. 18

II

31.2

18.9

2 : 1. 21

III

27-3

16.8

2 : 1.23

IV

33

19.8

2 : 1.2

VI

31.6

19-5

2 : 1.23

VII

35-8

22.5

2 : 1.26

As, however, the composition of nitrogen iodide has been
definitel)^ determined, the amount which actually reacts with
the hydrogen sulphide and consequently the quantity of
hydriodic acid liberated can be calculated from the ammonia
formed. In the following experiments this was done, the
nitrogen iodide which breaks up into nitrogen and hydriodic
acid being neglected :

Number of
experiment.

10 2

oxidized,
cc.

produced,
cc.

Ratio.

I

II
III

30.8
24.7
32.2

15-4
12.3
16.2

2 : I

2 : 0.995

2 : 1.006

IV

VI
VII

40.4
26.8
20.9

20.3

13-4
10.5

2 : 1.005

2 : I

2 : 1.004

It is seen that the action of h3^drogen sulphide upon nitro-
gen iodide is perfectly normal and that the amount of hj^dro-
gen sulphide oxidized is twice that equivalent to the hydri-
odic acid produced.

The close agreement between all the results obtained with
such very different reducing agents places it beyond doubt
that, when nitrogen iodide reacts with any reducing agent,
the ratio between the amount of the latter oxidized and that
of the hydriodic acid produced is as 2 : i ; in other words,

1 Compare Bineau's (Ann. chira. phys. [3], 15, 71 (1S45)) and Gladstone's (Chem.
Soc. J., 4, 34 (1S52), and 7, 51 (1S54)) analytical results obtained by this method. They
differ among themselves, and this accompanying decomposition was not observed.

376 Jackson a7id Gazzolo.

that the iodine contained in nitrogen iodide behaves in these
reactions like the chlorine contained in a hypochlorite and
exerts twice its normal oxidizing action.

Chemical Laboratory, St. Bar-
tholomew's Hospital and
College, London.

Contributions from the Chemical Laboratory of Harvard College.

CXVII.— ON CERTAIN COLORED SUBSTANCES DE-
RIVED FROM NITRO COMPOUNDS.

[third paper.']

By C. Loring Jackson and F. H. Gazzolo.

The colored substances formed by the action of sodic alco-
holates and certain nitro compounds have been studied by
Victor Meyer, ^ Eobry de Bruyn,' and in this laboratory/ but
as yet no satisfactory constitutional formula has been assigned
to them.

In continuing this investigation we tried first to replace the
sodic alcoholates by other similar reagents, and succeeded in
obtaining colored products from trinitranisol or trinitrobenzol
by the action of sodic malonic ester, sodic acetacetic ester,
sodic phenylate, the sodium compound of benzyl cyanide, and
perhaps the sodium compound of phloroglucine, although in
this last case the action was not well marked. As it has been
shown already that similar compounds are formed with various
sodic alcoholates,^ and even with sodic hydrate,* it appears
that this behavior with nitro compounds is a very general re-
action of alkaline substances.

Of these new colored products only those wdth sodic malonic
ester or sodic acetacetic ester were stable enough to be pre-
pared for analysis, but they were unusually stable for bodies
of this class. All four of the substances formed from trini-
tranisol or trinitrobenzol, and these two sodium esters were
analyzed and were proved to consist of 3 molecules of the

1 Preseuted to the American Academy of Arts and Sciences, December 13, 1899.

2 Ber. d. chem. Ges., 27, 3153 ; 29, 848.

3 Rec. Trav. Chim. Pays-Bas., 14, 89, 150; 15, 848.

* Jackson and Ittner : This Journal, 19, 199, where a historical account of the
previous work is given ; Jackson and Boos : Ibid., 20, 444.
5 Ibid., 20, 444.
6Hepp : Ann. Chem. (Liebig), 215, 359.

Colored Substayices Derived from Niiro Compotinds. 377

sodium ester combined with i of the trinitro compound ; for
instance, the raalonic ester trinitrobenzol compound has this
formula, C,H,(N0J,[CHNa(C00C,H,),]3. The formation
of compounds with 3 molecules of the sodium constituent is
noteworthy, since all the compounds analyzed heretofore have
contained the two constituents in the proportion of i molecule
of each. Similar experiments with sodic methylate, ethylate,
or amylate and trinitrobenzol also led to products apparently
containing 3 molecules of the alcoholate to each molecule of
the nitro compound' — a surprising result, since Lobry de
Bruyn and Van Leent* obtained from trinitrobenzol a substance
with the following formula, C.H,(NOj3KOCH3iH,0. The
difference in the result is unquestionabl}^ due to differences in
the method of preparation. Lobry de Bruyn and Van Leent's
compound was obtained by crystallization, whereas all our
products with 3 molecules of the alkaline material were pre-
cipitated from an alcoholic solution with benzol. Experi-
ments are now in progress to test this explanation of the phe-
nomena.

The discovery of these sodic malonic or acetacetic com-
pounds would furnish a strong argument, if that were needed,
against the only theory of these colored substances as yet
published — that of Victor Meyer, ^ who supposed they were
formed by the replacement of atoms of hydrogen on the ben-
zol ring by atoms of sodium. This theory has been disproved
by the obser^^ations of Lobry de Bruyn, ■* supported by those
made in this laboratory ;' and among other arguments the
point was made that Victor Meyer's theory necessitated the
assumption of alcohol of crystallization in every compound of
this class which had been analyzed. In these malonic and
acetacetic compounds the presence of malonic ester or acetace-
tic ester of crystallization must be assumed, if this theory is

1 The ethyl and methyl compounds seemed to contain alcohol of crystallization,
to judge from the percentages of sodium obtained. The publication of these results
will, therefore, be postponed until further analytical data have been collected. The
amyl compound, on the other hand, gave a percentage of sodium corresponding to
C6H3(NO,)3(NaOCsHi,)3.

- Rec. Trav. Chim. Pays-Bas., 14, 150.

3 Ber. d. chem. Ges., 27, 3153.

* Rec. Trav. Chim. Pays-Bas., 14, Sg.

5 This Journal, ao, 445-

378 Jackson and Gazzolo.

adopted ; and, further, the number of molecules of " ester of
crystallization" corresponds in each case to the number of
atoms of sodium ; the view, therefore, that the colored bodies
are addition and not substitution compounds is confirmed by
these observations.

Other experiments were tried to study the effect on the
formation of the colors of increasing or diminishing the nega-
tive nature of the aromatic constituent. That there is some
effect of this sort has been shown already, since certain sub-
stituted toluols give less stable colored derivatives than the
corresponding benzoic acids. ^ Picramide, the first substance
selected for this work, gave colored compounds with sodic
methylate or sodic malonic ester, but too unstable to analyze,
whereas trinitranisol or trinitrobenzol, in which the negative
character of the nitro groups is not weakened by the presence
of a positive radical like NH,, gave stable, well-marked
colors. Dinitroxylol ((CH3),i.3.(N02),4.6) also gave a
slight and evanescent coloration with sodic methylate, and no
reaction with sodic malonic ester, whereas trinitroxylol
((0113)51.3. (NOJ32. 4. 6) gave colored compounds with both
these reagents, which, although much more stable, could not
be prepared for analysis. These results, therefore, as far as
they go, show that an increase in the negative nature of the
aromatic constituent increases the tendency to form colored
compounds.

The next subject considered by us was the effect of the
presence of methyl groups attached to the benzol ring on the
formation of colors. Dinitrotoluol ((NOJ22.4) gave colored
compounds with sodic methylate or sodic malonic ester ; di-
nitroxylol ((CH,)2i.3.(NOj54.6) gave only a passing colora-
tion* with sodic methylate, none at all with sodic malonic
ester ; and dinitromesitylene gave no color with either reagent.
Trinitroxylol gave strong color reactions with both reagents;
trinitromesitylene none whatever. It is evident, therefore,
that the presence of methyl groups on the benzol ring dimin-
ishes the tendency to form these colored compounds. Whether

iThis Journal 19, 201.

2 This may have been due to a small quantity of a thiophene compound. As a
rule we have not considered that a colored product belonged to the class we are
studying unless we could obtain a copious precipitate of it with benzol.

Colored Substances Derived from Nitro Compounds. 379

this effect is due to a specific action' of the methyl group, or to
the fact that these groups stand in the ortho position to the
nitro groups, or to both these causes, cannot be determined
from the facts at present at our disposal.

In consideration of the complete absence of a color reaction
with trinitromesitylene and sodic methylate, it is interesting
to note that M. Konowalow^ obtained red salts from nitromesi-
tylenes in which one of the nitro groups stands in the side
chain. We cannot find that he analyzed these salts to deter-
mine whether they were true salts or addition-products with
sodic hydrate. If the latter, they would have a strong bear-
ing on the discussion given above.

Another series of experiments was tried with aromatic
bodies rich in negative radicals by containing no nitro groups ;
for, if colors of the same class could be obtained from these, it
would prove that the addition of the alkaline substance took
place on the benzol ring and not on the nitro group. We
were encouraged to undertake these experiments by the
striking resemblance in properties^ between our colored prod-
ucts and the green bodies made by Astre" from the action of
sodic alcoholates on quinone. In the quinones, however, the
formation of hemiacetals' is possible, and it may be that the
green bodies belonged to this class ; we accordingly used for
our new experiments substances in which the formation of
hemiacetals could not occur, such as trimesic triethylester,
which is especially fit for these experiments, since it has a
still stronger resemblance to trinitrobenzol than quinone has,
because it contains three negative radicals symmetrically dis-
posed. We have not succeeded in obtaining any colored or
other addition-products from this substance, or from the free
trimesic acid, although the attempts have been repeated often
and under varying conditions. Nor did we have better suc-
cess with other bodies free from nitro groups, such as phloro-
glucine, or resorcine ; pyrocatechine, it is true, gave a tem-
porary coloration with sodic methjdate, but we think this re-

1 Lobry de Bruyn : Rec. Trav. Chim. Pays-Bas., 14, 95.

2 Ber. d. chem. Ges., 29, 2204.
8 This Journal, 20, 446.

4 Compt. rend., 121, 530 (1895).

5 This Journal, 17, 579, 633.

380 Jackson and Gazzolo.

action does not belong to the series under discussion. These
experiments, as thej^ have given negative results, throw no
light on the constitution of our colored compounds.

It has been shown earlier in this paper that the only theory
as yet proposed for these colored compounds (that of Victor
Meyer) is inadmissible, because they are addition-, not sub-
stitution-products. The facts now at our disposal are not
sufficient to furnish an absolute proof of the structure of these
compounds, but it is possible to show that certain constitu-
tional formulas explain these facts better than others, and it
seems to us that the work has arrived at a point where such a
discussion of the possible formulas will be useful. In this
discussion the following properties must be considered, as
they seem to be characteristic of all the members of this
group: (i) The very marked color. (2) The ease with
which they are decomposed even by dilute acids, giving the
aromatic constitution unaltered. (3) Their behavior with
alcohols, which we describe here in some detail, because the
principal observations are new. When the methyl compound,
C,H,(NO,)30CH3NaOCH3, is allowed to stand for some time
with benzyl alcohol, both the methyls are replaced by benzyls,
and the compound CeH,(NOj30C,H,NaOC,H, is formed.
Conversely this benzyl compound is converted into the corre-
sponding methyl compound if boiled with methyl alcohol. In
the same way' the methyl is converted into the ethyl com-
pound by crj^stallization from common alcohol.'

There are three possible ways in which these compounds
can be formed : First, The addition of the sodic methylate (or
other alkaline substance) may take place upon the carbon
atoms of the benzol ring. Second, It may take place on the
nitro group alone. Third, It may take place partly on the
nitro group and partly on the carbon of the benzol ring.

i This Journal, 20, 449.

2 Some experiments of less importance may be mentioned here, with the remark
that they are not incompatible with the formula adopted later as giving the best ex-
planation of the observed facts. Bromine decomposes the salt

C6H3(N02)3[CHNa(COOC5H5),]„
giving trinitrobenzol as one of the products of the reaction. No salts with other
basic radicals could be obtained from CeH3(N02)j0CH3Na0CH3. No sodic iodide
was formed by heating C6H3(N02)3[CHNa(COOC2H5)2l3 with ethyl iodide to 140°. On
the other hand, it looked as if benzoyl chloride acted on these bodies, but the end of
the college year prevented us from studj'ing this reaction.

Colored Substances Derived from Nitro Compounds. 381

The first method of addition, that on the carbon alone,
seems to us much less probable than the second or third, in
which a nitro group takes part, especially since the work of
Nef and others has shown that the sodium is attached to the
nitro group in the sodium salt of nitromethane. As we have
succeeded in finding no analogous case in which an alkaline
substance is added to carbon atoms with the formation of a
strongly colored product, we think that this first hypothesis is
not worthy of a detailed discussion.

Turning to the formulas in which the nitro group is affected,
we have the second method of addition, in which the sodic
methylate is attached to the nitro group only ; this would
give rise to a structure such as the following :'

/OCH3
C.H,0CH3(N0,)-N/ ;

II ^ONa
O
I.

while the third hypothesis, according to which both the nitro
group and the carbon of the phenol ring take part in the ad-
dition, would be represented by the formulas given below, in
which it is supposed that an isonitro^ compound is formed
with the development of a quinoid structure in the benzol
ring. The difference between the two formulas is that in II
the quinoid structure is developed in the para position, in III
in the ortho position :

0=N— O— Na

0=N— O— Na

CH,0 OCH.

II.

III.

iThis is analogous to that given by Hantzsch and Rinckenberger (Ber. d. chem.
Ges., 32, 628) for their dinitroethanester acid.

" Compare Hantzsch (Ber. d. chem. Ges., 32, 575-651) and also the orthobenzoldi-
oxime of Zincke and Schwarz (Ann. Chem. (Liebig), 307, 28).

382 Jackson and Gazzolo.

We have used the formula of the addition-product from
sodic methj'late and trinitranisol, as it is the simplest that
will ser\'e in the argument which follows. In applying these
formulas to the malonic ester compounds it must be assumed
that the malonic ester radical which is added to the benzol
ring has the constitution — OC(OC„H,)=:CHCOOC„H,, as,
if it is assumed to be — CH(COOC„Hj)j, we should have an
attachment of carbon to carbon incompatible with the insta-
bility of these compounds.

In applying formulas I, II, and III to the explanation of
the observed properties of these compounds, we consider first
the strong color, their most marked characteristic ; this is
explained b^' the quinoid structure in formulas II or III,
but is not accounted for by formula I, since, according to
Hantzsch and Rinckenberger,' their subsubstance

CH, oan,

\ /

CH— NO

/ \

NO, OK

which contains the group characteristic of formula I, has only
a pale-yellow color.

The easy decomposition of the colored body by hydro-
chloric acid with regeneration of the trinitranisol, from which
it was formed, is accounted for by either of the three formu-
las, I, II, or III, but the preference should be given to II or
III, since Hantzsch and Rinckberger' state that their com-
pound

CH3 OC,H,

\ /

CH— NO

/ \

NO, OH

is a true stable acid ten times as strong as acetic acid, and it
is fair to suppose, therefore, that the substance

/OCH,

C,H,0CH3(N0J,N0<

^OH

1 Ber. d. chem. Ges., 32, 62S.

2 Ibid.

Colored Substances Derived from Nitro Compounds. 383

(formed by hydrochloric acid on our sodium salt, if it has
formula I) would also be comparatively stable, and not drop
at once into the trinitranisol, which, as a matter of fact, is
formed immediately by the action of hydrochloric acid on the
colored compound. On the other hand, this rapid decompo-
sition by acid would be explained according to formula II or
III by the strong tendencj^ of quinoid bodies to pass into the
hydroquinoid form, which might easily cause the splitting off
of methyl alcohol as soon as the atom of sodium was replaced
by hydrogen. This rapid decomposition with removal of
methyl alcohol when the colored bodies are treated with dilute
hydrochlyric acid recalls the similar behavior of the dichlor-
dimethoxyquinonedimethylhemiacetal ;' and the similarity of
these phenomena may tell in favor of classing the colored
salts with quinoue derivatives, although the two reactions are
not strictly analogous.

The third point in favor of formula II or III is the replace-
ment of the two methyls in CeH,(NOj30CH,NaOCH, by
benzyls when the compound is soaked in benzyl alcohol, and
the reverse change when the benzyl compound is boiled with
methyl alcohol. As under the same conditions benzyl alcohol
has no action on methyl picrate, or methyl alcohol on benzyl
picrate, it is obvious that the complete replacement of one
radical by the other here depends on the structure of the ad-
dition-product ; and, whereas formula I gives no reason why
the change should proceed beyond the method attached to the
nitro group, it is easy to see that in a substance constituted
like formula II or III any reagent which affected one methyl
would act in a similar way on the other, so that the methyl
compound would be completeh'- converted into

C.H,(NO,),OC,H,NaOC,H,.

The inferences drawn in the foregoing discussion may be
briefly recapitulated as follows : It is improbable that the
sodic methylate is added to the carbon of the benzol ring only.
A quinoid formula (II or III) explains the observed facts bet-
ter than one in which the sodic methylate is added to the nitro
group alone (I), but this latter structure is not definitely ex-

1 This Journal, 17, 604.

384 Jackson and Gazzolo.

eluded. Under these circumstances we think it would be pre-
mature to contrive names for these colored bodies, or to give
structural formulas in the experimental part of this paper.
We hope that a continuation of the work, now in progress in
this laboratory, will definitely settle the constitution of these
colored substances.

EXPERIMENTAL PART.

Preparation of Fiery I Chloride.

As the method of making picryl chloride used by us in this
work is an improvement on that given by Pisani,' we de-
scribe it. Twenty-five grams of dry picric acid were mixed
with 50 grams of phosphoric pentachloride in a large Erlen-
meyer flask provided wnth an air condenser, and heated on the
water-bath until the violent reaction had ceased, and the con-
tents had assumed a very dark-brown color. When cold, the
flask was surrounded with ice, and its contents treated with
ice-water, care being taken to avoid any considerable rise of
temperature. The precipitate formed in this way was filtered
out, dried, washed with ether, and crj^stallized from a mixture
of benzol and alcohol to purify it. The advantages in our
method are that there is a considerable saving of time, and
there is much less danger that the substance will be converted
into a tarry decomposition-product, as happens in Pisani's
method if the heat runs too high in either the preparation or
the removal of the phosphoric oxychloride by distillation.

Action of Sodic Acetacetic Ester with Trtnitranisol .

In our first experiment in this direction we prepared our
sodic acetacetic ester with sodic methylate, and obtained a
red precipitate which gave the following result on analysis :

0.2438 gram substance gave 0.0576 gram Na^SO^.

Calculated for
CeH,(N02)30CH3NaOCH,. Found.

Na 7.69 7.66

It was evident, therefore, that we had only the color formed
from sodic methylate, and that the acetacetic ester took no part
in the reaction. In order, then, to obtain an acetacetic ester

1 Ann. Chem. (Liebig), 92, 326.

Colored Substances Derived from Nitro Compounds. 385

addition, it was obviously necessary to exclude all alcohol and
alcoliolates ; we accordingly proceeded as follows : To an ex-
cess of acetacetic ester mixed with benzol a quantity of sodium
in the form of ribbon was added (in our later preparation the
amount of sodium used provided 3 atoms of it to each mole-
cule of trinitranisol). After the sodium had disappeared, the
liquid thus obtained was added drop by drop to a benzol solu-
tion of trinitranisol. It is unnecessary to say that absolute
benzol was used in all this work. The first drop imparted a
deep vermilion color to the solution, and this color became
more and more intense as the reaction proceeded. During
the process the mixture was kept cool by surrounding the
beaker with ice. After all the sodic acetacetic ester had been
added, the liquid was mixed with an excess of anhydrous
benzol, which threw down a semi-gelatinous or oily precipi-
tate. This was filtered out, washed with benzol, and pressed
upon a porous plate, all these operations being carried on as
quickly as possible. The dark-colored dried product crumbled
easily into a red amorphous powder of a much darker color
than the addition-product from sodic methylate. It was dried
in vacuo and analyzed with the following results :

I. 0.2376 gram substance gave 0.0740 gram Na,SO,.

II. 0.2196 gram substance gave 0.0697 gram Na„SO^.

III. 0.1928 gram substance gave 0.0700 gram Na^SO^.

IV. 0.2596 gram substance gave on combustion 0.4028
gam CO, and 0.1148 gram H,0. In this combustion the sub-
stance was mixed with chromic oxide to drive out carbonic
dioxide from the carbonate formed, and was spread out in a
long copper boat, which was heated gently and gradually to
avoid explosions.

lated for Found.

IV. ^

42.32
4.91

There can be no doubt, therefore, as each analysis is of the
product of a separate preparation, that the substance is a
definite compound, and is formed by the addition of 3 mole-
cules of sodic acetacetic ester to i of trinitranisol. The varia-

Calculated for

Found.

C(iH5(N05)30CH3(CH3C0CHNaC00C2H5)3

I.

II. III.

Na 9.87

10.10

10.28 II. 7

C 42- 9 1

....

H 4.57

....

386 Jackson and Gazzolo.

tion in the percentages of sodium in the different specimens is
no more than woiild be expected, when it is remembered that
the product was purified only by washing with benzol.

Properties of the Additio7i-prodtict of Trinitranisol and Sodic
Acetacetic Ester,

C.H,(NO,)30CH3(CH3COCHNaCOOC,Hj3.

This substance forms a deep crimson powder, which we
have not succeeded in bringing into a crystalline state. It is
decidedly stable for a body of this class, keeping for sev-
eral da5'^s in a desiccator, but finally decompo.sing into a
black tar. When heated it is slightly explosive. It dissolves
completely in water without decomposition, to judge from the
color ; is soluble in common alcohol, but gives a turbid solu-
tion ; on the other hand, it dissolves, forming a clear solution,
in meth3^1 alcohol ; soluble in acetone ; insoluble in benzol,
ether, chloroform, carbonic disulphide, or ligroin. Acids de-
compose it instantly, as was shown by the destruction of the
color.

Action of Sodic Malonic Ester on Trinitraiiisol .

Two grams of trinitranisol dissolved in absolute benzol were
mixed with a benzol solution of 4.5 grams of sodic malonic
ester prepared by the direct action of sodium on the malonic
ester, — that is, 3 molecules of the sodium ester to each mole-
cule of trinitranisol. As the two solutions came together, an
intense cherry-red color appeared, with the formation of a
thick gelatinous precipitate of the same color, which increased
in volume and deepened in color as the reaction continued.
After the mixture had stood some time at ordinary tempera-
tures, a large enough quantity of benzol was added to produce
complete precipitation, the product was then filtered rapidly,
washed with benzol till the filtrate was colorless, pressed
quickly on the porous plate, and dried in vacuo. This reac-
tion seemed to run more quickly and clearly than the corre-
sponding one with sodic acetacetic ester, giving a purer prod-
uct, which was very easily handled and washed.

I. 0.2028 gram substance gave 0.0536 gram Na„SO^.

II. 0.3027 gram substance gave 0.0796 gram Na^SO^.

Colored Substances Derived from Nitro Compounds. 387

Calculated for Found.

C4H2(NOj)30CHs[CHNa(COOC5HB)5]3. I. II.

Na 8.74 8.56 8.52

Properties of the Additio7i-product of Trinitranisol and Sodic

Malonic Ester,

C.H,(NOJ,OCH3[CHNa(COOC,Hjj3.

This substance is an amorphous powder with a deep ma-
roon color. We have not succeeded in crystallizing it. It is
one of the most stable bodies of its class, as when exposed to
the air it usually remains unaltered for nearly five daj^s ; at
the end of this time it begins to grow moist, then turns black,
and is finally converted into a black powder with a somewhat
tarry consistency. When heated it explodes with a slight
puff, but with little or no noise ; it is, however, apparently
stable at as high a temperature as 140°. It dissolves com-
pletely in water, forming a clear cherry-red solution ; soluble,
although more slowly, in eth)^ alcohol ; completely and quickly
soluble in methyl alcohol, but this solution seems to be at-
tended by some decomposition, as a fading of the color was
observed ; soluble in acetone ; insoluble in ether, benzol,
chloroform, carbonic disulphide, or ligroin. A few drops of
hydrochloric acid added to its aqueous solution changes the
red color to yellow instantly, and causes a precipitate which,
on filtration, solution in alcohol, and evaporation of the sol-
vent, proves to be a reddish oil containing malonic ester, to
judge from the smell, and trinitranisol, since this substance
crystallizes out on standing.

As this substance was more stable than most others of its
class, we tried the action of ethjd iodide upon it in the hope
of replacing the atoms of sodium with ethyl. For this pur-
pose 0.5 gram of the addition-product was heated in a sealed
tube with ethyl iodide, at first to 100°, but, as this produced
no apparent effect, later to 140° for an hour and a half, and
then it was kept at 100° for two days. The contents of the
tube were treated with benzol, after the ethyl iodide had evap-
orated, which gave a red solution and a black residue ; the
residue was extracted with water, and the extract gave no
test for an iodide. It is obvious, therefore, that the ethyl
iodide had not acted at all, but that the unmanageable black

388 Jackson and Gazzolo.

product was produced by the decomposition of the addition
compound.

Action of Sodic Malonic Ester with Trinitrobenzol .

The sodic malonic ester was prepared with sodium alone,
benzol was used as the solvent, and the proportions were 3
molecules of the ester to i of the trinitrobenzol. As soon as
the solutions were mixed, a deep-scarlet, lumpy precipitate
was formed ; it was found best, therefore, to add the solution
of the sodic malonic ester in small portions at a time with con-
stant stirring. The beaker was cooled by immersing it in
ice. The precipitate was washed with benzol until the filtrate
was colorless, and then dried on a porous plate and in vacuo.
Analyses I and II are of 2 different products prepared in this
way. As in these preparations and the other similar one
described in this paper we had used 3 molecules of the sodium
compound to one of the nitro body, there seemed some danger
that our products might not be definite compounds, but mix-
tures of an addition compound containing only i atom of
sodium, with the two additional molecules of the sodic malonic
ester (or the corresponding reagent) precipitated by the large
excess of the benzol. This objection to our results did not
seem a very important one, because they agreed better with
the theoretical numbers than would be probable if this theory
were true, but we felt that it was necessary to test it by ex-
periment, and for this purpose repeated the preparation, using
2 molecules of sodic malonic ester to each molecule of trini-
trobenzol (i gram of trinitrobenzol and 1.7 grams of the sodic
malonic ester) . Analysis III was made with the specimen
prepared in this way, and proves that our substances are defi-
nite compounds and not mixtures, since it agrees with those
prepared with 3 molecules of the sodium ester.

I. 0.2038 gram substance gave 0.0544 gram Na,SO^.

II. 0.2154 gram substance gave 0.0590 gram NajSO^.

III. 0.2630 gram substance gave 0.0756 gram Na,SO^.

Calculated for Found.

C6H3(N02)j[CHNa(C00CjH6),]3. I. II. III.

Na 9.09 8.66 8.87 9.31

Colored Substances Derived from Nitro Compounds. 389

Properties of the Addition -product of Triniirobenzol and Sodic

Malonic Ester,

C.H3(NO,)3[CHNa(COOC,HJj3.

This body has a rich maroon color brighter than that of the
corresponding compound of trinitranisol and sodic malonic
ester. It is stable for some Lime if kept dry and cool, other-
wise it gradually undergoes decomposition, as shown by its
change of color and becoming gummy. In its other proper-
ties it resembles the corresponding trinitranisol compound
most closely. When treated with hydrochloric acid the color
is destroyed, and a thick brownish-yellow precipitate is
formed ; by washing this with small quantities of alcohol to
remove the malonic ester the trinitrobenzol was recovered in
quantity, and recognized by its melting-point, I2i°-i22°, after
crystallization from benzol. As soon, therefore, as the three
atoms of sodium are replaced by hydrogen the addition-prod-
uct splits into its constituents.

Action of Bromine on the Addition-product of Trinitrobenzol and
Sodic Malonic Ester.

The addition-product, C,H3(NO,)3[CHNa(COOC,HJj3,
was added in small successive portions to a chloroform solu-
tion of bromine cooled by immersing the vessel in ice. The
color of the solid changed instantly from maroon to white.
After the mixture had stood over night, the solid was filtered
out and the filtrate allowed to evaporate spontaneously, when
it left a thick brownish-red oil, which, after standing two
days, deposited crystals identified as trinitrobenzol by their
melting-point, 221°, the form of the crystals, and the forma-
tion of the characteristic red color with sodic alcoholates. The
portion insoluble in chloroform, after thorough washing with
chloroform and boiling benzol, proved to be sodic bromide.
This experiment does not absolutely disprove the formation
of some bromtrinitrobenzol, since a small amount of it might
have remained dissolved in the oil from which the trinitro-
benzol was deposited, but it shows that trinitrobenzol is one
of the principal products of the reaction ; and as this separated
from the oil in a nearly pure state, it is very probable at least
that no bromtrinitrobenzol was formed.

Calculated for
C6H3(N02)3[CH3COCHNaCOOC3H6l3. I.

Found.
II.

Na 10.32 10.82

10.56

390 Jackson and Gazzolo.

Action of Acetacetic Ester on Trinitrobenzol .
The product was prepared in the same way as the corre-
sponding addition compound of trinitrobenzol and sodic ma-
lonic ester. In this case the precipitate had a deeper red
color than that produced with sodic malonic ester, and the
reaction ran less neatly. Analyses of three different prepara-
tions dried i7i vacuo gav^e the following results :

I. 0.1865 gram substance gave 0.0623 gram Na.jS04.

II. 0.2017 gram substance gave 0.0658 gram Na,SO^.

III. 0.2104 gram substance gave 0.0680 gram Na^SO^.

III.
10.47

The addition-product of trinitrobenzol and sodic acetacetic
ester is a rich brownish-red amorphous powder darker than
the corresponding product from trinitrobenzol and sodic ma-
lonic ester. It is fairly stable if kept dry. In its other prop-
erties it is exactly similar to the colored substances already
described in this paper.

Preparation of the Irisodic Avtylate Addition-product of Trini-
trobenzol.
To a benzol solution of i gram of trinitrobenzol 1.5 grams
of sodic amylate were added gradually, care being taken to
keep the mixture cool. The proportions are 3 molecules of
the amylate to each molecule of trinitrobenzol. A heavy
scarlet precipitate was formed as soon as the substances came
together ; this was filtered quickly, thoroughly washed with
benzol, and dried on a porous plate, after which it was analyzed,
with the following results :

I. 0.2596 gram substance gave 0.1070 gram Na^SO,.

II. 0.1700 gram substance gave 0.0680 gram Na^SO^.

III. 0.3190 gram substance gave 0.1288 gram Na^SO^.

Calculated for Found.

C,H,(N05)3(C6H,i0Na)3. I. II. III.

Na 12.71 13-36 12.96 13.07

Properties of Trisodic Avtylate Addition Compound of Trhiitro-
benzol, C,H,(NOj3(C,H,,ONa)3.
The dry substance is a dark-crimson amorphous powder.

Colored Substances Derived front Nitro Compounds. 391

It is remarkably stable for bodies of this class, since it did not
change in color, or show any tendency to become moist, even
after standing for two weeks in contact with the air. It is
soluble in ethyl or methyl alcohol or acetone ; very soluble in
water ; insoluble in benzol, chloroform, carbonic disulphide,
or ligroin. The strong acids decompose it at once, giving
trinitrobenzol as one of the decomposition-products.

Upon treating trinitrobenzol with sodic methylate or sodic
ethylate under the same conditions, products were obtained
with the following formulas, if we may judge from the sodium
determinations :

C,H3(NOj3(CH30Na),CH30H,
and C,H3(NO,)3(C,H,ONa)3C,H,OH,

but as these seem an insufficient foundation for such formulas,
we shall postpone the description of these substances until we
have collected sufficient analytical data to establish their
composition. They are both red, but decompose more rapidly
than the amylate, becoming moist and discolored after ex-
posure to the air for a few hours. Heating also decomposes
the methylate body, so that the presence of methyl alcohol of
crystallization could not be established in this way. The
discussion of the conditions under which these tri bodies are
formed instead of the mono compounds will also be postponed
until it has been thoroughly settled by further experiments.

Attempts to obtain Colored Compounds with other Reagents.

Sodic phenylate, made by adding sodium to an excess of
phenol, gave with trinitrobenzol a clear red color, but no pre-
cipitate. A similar result was obtained when an alcoholic
solution of sodic phenylate was added to a benzol solution of
trinitranisol ; but this latter coloration does not necessarily
proceed from the sodic phenylate, as part of it may have been
converted into sodic ethylate by the alcohol.

Sodic hydrate also gives a red color with trinitrobenzol, as
was observed by Hepp,' but as there seemed little chance of
isolating this in a state fit for analysis, we did not attempt to
study it.

1 Ann. Chem. (Liebig), 215, 359.

392 Jackson and Gazzolo.

The sodium salt of phloroglucine, made by treating an ex-
cess of it with sodic hydrate, gave a light-reddish color when
treated with a benzol solution of trinitrobenzol, and upon add-
ing an excess of benzol a most uninviting sticky precipitate
was formed which it would have been foolish to try to analyze.
We doubt whether this colored substance was really a phloro-
glucine compound, as it is very possible that it was formed
from a little sodic hydrate produced by the decomposition of
the sodium salt of the phloroglucine.

Benzj'l cyanide, treated with metallic sodium, after the
slight action with the sodium was finished, was mixed with
trinitrobenzol. Upon stirring for a few seconds a deep blood-
red precipitate appeared in large quantity ; but it was so un-
stable that even the addition of benzol to wash out the excess
of benzyl cyanide converted it into a black, tarry mass, so that
we were obliged to give up all idea of analyzing it.

Attempts to obtain Colored Compounds from other Nitro Bodies.

Picramide, CeH^CNOJ^NH,, treated with a mixture of
sodic methylate, methyl alcohol, and anhydrous benzol, gave
at once a strongly colored, dark-crimson solution, which de-
posited a brick-red precipitate ; but in collecting it for analy-
sis the substance decomposed as soon as it dried on the por-
ous plate, forming a brownish mass, which later became
tarry. We were unable, therefore, to make an analysis.

Trichlorbromdinitrobenzol (Cl3i.3.5.Br2(NOJ,4.6) gives a
strong vermilion color with an alcoholic solution of sodic
ethylate, as already stated by us in a previous paper.'

Dinitrotoluol ((N02)52.4) melting at 70°. 5, gave with sodic
methylate a deep vermilion-colored solution, from which a
precipitate was obtained with an excess of benzol. A benzol
solution of the dinitrotoluol gave with sodic malonic ester a
crimson-red solution and a colored precipitate, but both this
and the precipitate of the methylate compound decomposed
while drying on the porous plate.

Symmetrical dinitroxylol, melting at 93°,

((CH3)j.3.(NOJ,4-6),
gave with sodic methylate, after a few seconds, a faint green-
ly This Journal, 22, 58.

Colored Substances Derived from Nitro Compounds. 393

ish color, which turned rapidly to a deep purple, and finally
became brownish-black. It was evidently, therefore, very
unstable. Neither sodic malonic ester nor sodic acetacetic
ester gave any trace of color.

Trinitroxylol ((CH3)ji.3. (N05)32.4.6) gave a deep cherry-
red solution with either sodic methylate or a benzol solution
of sodic malonic ester or of sodic acetacetic ester. An excess
of benzol precipitated from each of these solutions a gummy,
reddish body, which decomposed before it could be prepared
for analysis. In these cases the decomposition-product had a
pinkish-white color.

Neither dinitromesitylene nor trinitromesitylene gave a
trace of color after standing with sodic methylate. At the
moment the trinitromesitylene was mixed with the sodic
methylate we thought in one or two cases we perceived a very
faint coloration, but it was so indistinct that we felt doubtful
of its existence, and at best it was ver)' evanescent. Sodic
malonic ester and sodic acetacetic ester also gave negative re-
sults with both these bodies.

Dinitrophloroglucinetriethyl ether, C.HCOC^HJjCNOJ,,
gave no color with sodic methylate, sodic malonic ester, or
sodic acetacetic ester.

Attempts to Obtain Colored Compounds froTn Bodies which Contain
no Nitro Group.

Pyrocatechin gave no color with sodic malonic ester, but
with sodic methylate a bright-green color was formed along
the edges, which soon darkened, and finally gave a black oil.
This coloration is probably similar to those observed by Kunz
Krause' on treating various phenols with sodium and alcohol,
but we do not feel sure that these colors are related to those
obtained from nitro compounds.

Resorcine gave no color with either sodic methylate, sodic
malonic ester, or sodic acetacetic ester. The same negative
results were obtained with phloroglucine. -

Neither trimesic acid, ((COOH),i.3.5), nor its ester,
CgHjCCOOCjHJj, gave any sign of sodic methylate, although
the experiments were tried with great care, and under condi-

1 Arch. Pharm., a36, 542.

394 Jackson and Gazzolo.

tions which gave colors even with some of the less reactive
nitro compounds.

Experiments on the Replacement of the Ally I Radical in the Col-
ored Compozinds.

Action of Methyl Alcohol 07i the Benzyl Compound. — The ad-
dition product of benzyl picrate and sodic benzylate, discov-
ered by W. F. Boos and one of us,' was heated with methyl
alcohol for about half an hour, and the methyl alcohol was
then allowed to evaporate at ordinary temperatures. The
product consisted of glistening scarlet crystals, which were at
once decolorized by hydrochloric acid, yielding a substance
melting at 64°, and crystallizing in yellow rhombic plates from
benzol. It w^as therefore trinitranisol, and the methyl alcohol
had replaced the benzyl groups in the original addition-com-
pound by two methyls.

Action of Methyl Alcohol on Benzyl Picrate. — Benzyl picrate
was prepared according to the method given by Boos and one
of us." The melting-point of this substance is 145°, not 115°
as given in the paper just cited ; the number 115° was due to
a mistake in copying the melting-point from the note-book.
A quantity of the benzyl picrate was recrystallized four times
from boiling methyl alcohol, and after each crystallization the
melting-point remained constant at 145°, thus showing that
the benzyl picrate is not converted into methyl picrate by
methyl alcohol at its boiling-point.

Action of Benzyl Alcohol on the Addition-product of Trini-
tra?iisol and Sodic Methylate. — The colored compound was dis-
solved in benzyl alcohol with the aid of gentle heat, and the
mixture was allowed to stand at ordinary temperatures until
crystals separated. The red substance obtained in this way
was decomposed with hydrochloric acid, when the product,
after crystallization, showed the constant melting-point 145°,
and was therefore benzyl picrate. In this case, therefore, the
benzyl alcohol had converted the colored methyl compound
into the corresponding benzyl compound.

Action of Benzyl Alcohol 07i Tri^iitranisol . — A solution of

I This Journal, ao, 452.
2/6id.,453.

Colored Substances Derived from Nitro Compounds. 395

trinitranisol in benzyl alcohol was allowed to stand in a
parafl&n desiccator until all the benzyl alcohol had evaporated;
the residue showed the melting-point of trinitranisol, 64°.

Benzyl alcohol, therefore, does not affect trinitranisol under
the conditions used in the experiment described in the last
paragraph.

Attempts to Prepare Derivatives from the Addition Compound
of Trinitranisol and Sodic Methylate.

Salts.— l:\i^ sodium salt, C,H,(NO,)30CH3NaOCH„ was
treated with the salts of various metals in the hope of obtain-
ing other salts. The chlorides of calcium, barium, mercury,
and zinc, in mixed methyla Icohol and aqueous solutions, pro-
duced no change. Cupric chloride, on the other hand,
formed a brown precipitate, from which trinitranisol was iso-
lated, and tests were obtained for copper and picric acid. We
decided, therefore, that the cupric chloride had decomposed
the colored compound, and neither this nor any of the other
experiments we tried seemed to point to the formation of salts
of the colored compounds by metathetical reactions.

Treatment with Benzoyl Chloride. — The addition compound
C,H,(NOj30CH,NaOCH3, if dissolved in methyl alcohol and
treated with benzoyl chloride, was at once decolorized, even
when sodic methylate was also present. Upon treating the
dry compound with benzoyl chloride, and allowing the mix-
ture to stand over night, the amorphous powder had become
converted into masses resembling cauliflower, with an even
more intense scarlet color than at first. An attempt to intro-
duce the benzoyl group by the Baumann-Schotten method led
to a similar result. One gram of the addition-product was
added to 25 grams of an 18 per cent solution of sodic hydrate,
and then 5 grams of benzoyl chloride were gradually poured
into the mixture ; the granular red powder was gradually
converted into masses resembling cauliflowers, most of which
dissolved in the alkaline liquid with a distinct intensification
of the red color. On acidifying with hydrochloric acid, the
color was discharged and a white precipitate of benzoic acid
was formed. The filtrate apparently contained picric acid.
Unfortunately we had not time to study this reaction more

39^ Jackson and Gazzolo.

carefully, but we hope it will be investigated in this labora-
tory during the coming year, and also that the behavior of
this compound with methyl iodide may be studied then.

Postscript. — The manuscript of the foregoing paper was
ready for the press, when I received an article' on colored
compounds of this class by Hantzsch and Kissel, in which
they ascribe to them formulas with the sodic alcoholate added
to the nitro group only (I) . I cannot find any reason in their
article for changing the conclusion to which I had already
come, that a quinoid formula (II or III) explains all the ob-
served facts better than the formula (I) adopted by them.
Their most important new facts are the isolation of the free
acid from the addition-product of potassic methylate and tri-
nitrotoluol, and the formation of the corresponding acetyl com-
pound, both of which are explained better by the quinoid for-
mula than by theirs. They also call attention to the fact that
the free acid is a weak one instead of being a strong one, as it
should be, if derived from a salt with their formula, and that
the marked color of the compounds would not be expected
from this structure ; both of these anomalies disappear if the
quinoid formula is adopted. It seems, therefore, that their
observations tend to confirm this quinoid formula.

The authors also claim to have disproved definitely the
theory of Victor Meyer that these bodies are substitution-
products, but neglect to mention that Lobry de Bruyn,^ in
1895, proved the incorrectness of this theory by treating tri-
nitrobenzol in boiling xylol with sodium. Therefore all sub-
sequent arguments against Victor Meyer's theory (of which I
have furnished three) must be considered as only confirma-
tory of Lobry de Bruyn's work.

It may not be out of place to repeat here that w^ork on this
subject is still in active progress in this laboratory.

C. LORiNG Jackson.
December 27, 1899.

1 Ber. d. chem. Ges., 32, 3137 (1899).

2 Rec. Trav. Chim. Pays-Bas., 14, 89.

THE SOLUTION-TENSION OF ZINC IN ETHYL
ALCOHOL.

By Harry C. Jones and Arthur W. Smith.

The conception of solution-tension of metals was first made
use of by Nernst' to explain the action of primary cells. The
chief seat of the electromotive force of such cells was shown
to be at the surfaces of contact of the electrodes with the elec-
trolytes. The magnitude of the potential which is produced
when a bar of metal is immersed in a solution of one of its
salts, is a function of two quantities : The osmotic pressure
of the cations of the dissolved salt, and the solution-tension of
the metal in question. These two forces act in opposition to
each other ; the osmotic pressure of the cations tending to
drive these ions out of solution on to the metal, while the
solution-tension of the metal tends to drive the metallic atoms
off from the bar as ions, which would then remain in the
solution.

The result of the reaction of these two opposing forces is to
produce around the bar of metal the well-known Helmholtz"
double layer. The metal atoms passing off into the solution
as ions, take positive electricity from the bar of metal which
thus becomes negative ; the solution into which these cations
pass, since it now contains an excess of cations, becomes pos-
itive.

The osmotic pressure of the cations, on the other hand,
drives cations out of the solution on to the metal, the metal
becoming positive due to the charge which it has received
from these cations when they passed over into metallic atoms ;
the solution, having lost some of its cations, becomes nega-
tively charged.

The action which will result in any given case depends upon
the relative values of the solution-tension of the metal and
the osmotic pressure of the cations of the salt.

There are three conditions possible. If we represent the
solution-tension of the metal by P, and the osmotic pressure
of the cations of the salt by p, we may have : (i) P > p ; (2)

1 Ztschr. phys. Chem., 4, 129.

2 Ann. der Phys. (Wied.), 7, 337.

398 Jones and Smith.

P =z p; (3) P < p. In the first case, where the solution-ten-
sion of the metal is greater than the osmotic pressure of the
cations, a small part of the metal will pass over into ions, or
as we generally say, will dissolve. These ions carry positive
electricity from the metal into the solution — the former be-
coming negative, the latter positive. The negative electricity
on the metal would attract, electrostatically, the positive ions
in the solution, and a double layer would be formed which
would tend to drive the metallic ions out of the solution on to
the metal. The attraction between the two parts of this double
layer, which tends to drive the metallic ions out of the solu-
tion, acts against the solution-tension of the metal, and equilib-
rium will be established when these two opposing forces are
equal.

If P < p, the above condition will be exactly reversed.
Cations will separate from the solution upon the metal, which
thus becomes positive with respect to the solution. The pos-
itive charge on the metal attracts, electrostatically, the nega-
tive ions in the liquid, and an electrical double layer is
formed, but the reverse of the above. Metallic ions will sepa-
rate from the solution until the electrostatic repulsion of these
ions by the positive metal is equal to the osmotic pressure
tending to force them out of solution.

In the second case, where P = p, nothing will happen. The
formula which has been deduced' for calculating the potential
between a metal and a solution of one of its salts is :

0.058 , P
n — — ^ log — ,
V '^ p'

in which n is the potential, v the valence of the metal, P the
solution-tension of the metal, and p the osmotic pressure of
the cations in the solution.

It is obvious that this equation can be used to calculate the
solution-tension of the metal. It is only necessary to solve
for log. P, and determine n and p.

It was supposed for a time that the solution-tension of a
metal is a constant, independent of the nature of the solvent

1 Nernst: Ztschr. phys. Chem., 4, 129 ; Ostwald : Lehr. d. allg. Chem., II, p. 851 ;
Le Blanc : Lehrb. d. Elektrochemie, p. 123 ; Jones : Theory of Electrolytic Dissocia-
tion, p. 236.

Zinc in Ethyl Alcohol. 399

in which it is immersed. Ostwald states' that "The solution-
tension of a metal is a constant peculiar to the metal, which
depends only on the temperature and generally increases with
rise in temperature."

On the assumption that the solution-tension of a metal is a
constant, Jones^ studied the following cell :

Ag-AgN0-AgN03— Ag.

(Aqueous) (Alcoholic)

The electromotive force of such an element can be calcu-
lated from the following equation :

7r = 0.058 ^log|i-log|^),

where p, is the osmotic pressure of the silver ions in the aque-
ous solution, Pj the solution-tension of the silver in this solu-
tion, P; the osmotic pressure of the silver ions in the alcoholic
solution, and Pj the solution-tension of the silver in this solu-
tion. But since the solution-tension of a metal is a constant,
Pj = Pj, everything in the above equation is already known
or could be measured, except pj, the osmotic pressure in the
alcoholic solution. It seemed very probable to Jones that he
had a general method for measuring dissociation in solvents
other than water. It was only necessary to construct a cell
using an aqueous solution of a salt of the electrode on one
side, and a solution in some other solvent upon the other, in
order to measure the dissociation of the salt in the other sol-
vent. But these hopes were soon abandoned.

If the solution-tension of silver is the same in the alcoholic
as in the aqueous solution, then the electrode immersed in the
aqueous solution must be positive against the electrode in the
alcoholic solution, since it was well known that p^ is greater
than Pj, The first point discovered by Jones was that the
alcoholic solution was positive against the aqueous. From
this it was at once evident that the solution-tension of silver
in the alcoholic solution was much less than in the aqueous
solution. He then determined the value of the solution-ten-

1 Lehr. der. allg. Chem., II, 852.

2 Ztschr. phys. Chem., 14, 346.

400 Jones and Smith.

sion in alcohol as compared with the solution-tension in water.
The above equation,

;r = 0.058 (log|i-log|^),

when solved for P, becomes :

if P,r= I, logP, =0.

Jones measured the electromotive force of a number of cells
containing an aqueous solution of silver nitrate on the one
side and an alcoholic solution on the other. He calculated
the solution-tension of silver in alcohol, using the approxi-
mate values for the dissociation of silver nitrate in alcohol
which had been furnished by VoUmer.' He found that the
solution-tension of silver in the alcoholic solution of its salt is
about one-twentieth of that in the aqueous solution.

Jones has recently attempted to measure more accurately
the dissociation of silver nitrate in ethyl alcohol, by means of
the improved boiling-point method,' which has proved so effi-
cient in other cases. He has, however, not been successful,
since silver nitrate in boiling ethyl alcohol always undergoes
more or less reduction.

The problem of the solution-tension of metals rested here
until quite recently.

Kahlenberg' has very greatly extended the work which was
begun by Jones. He has used a number of metals as elec-
trodes, and a number of solvents in which the salts of these
metals were dissolved, and has entirely substantiated the con-
clusion reached by Jones, that the solution-tension of a metal
is not a constant but varies for every solvent used.

He has not been able to calculate the absolute value of the
solution-tension of many of the metals in the different sol-
vents, because he had no means of measuring the dissociation
of the salts of these metals in the several solvents. He has
calculated the approximate solution-tension of silver in aceto-

1 Ann. der. Phys. (Wied.), 52, 328.

2 This Journal, 19, 581 ; Ztschr. phys. Chem., 31, 114.
8 J. Phys. Chetn., 3, 379.

Zinc in Ethyl Alcohol. 401

nitrile, and finds that it is greater than in water. Similar re-
sults were obtained with silver in pyridine.

Kahlenberg' adds that " further attempts to calculate solu-
tion-tensions will not be made, seeing that the requisite values
of p are not available ;" p being the dissociation of the salts
in the non-aqueous solutions.

It will be seen from the above that all that has been done,
even up to the present, is to determine the relative solution-
tensions of one metal — silver — in a very few solvents. Now
it so happens that silver stands at one of the extremes of the
tension series. It is the metal with the very smallest solution-
tension. This will be seen from the following table of metals
arranged in the order of their solution-tensions in aqueous
solutions of their salts.

Atmos.

Atmos.

Magnesium

10"^

Lead

10-2

Zinc

10'^

Copper

10-9

Aluminum

10'^

Mercury

IO~^5

Cadmium

10'

Silver

IO-'5

Iron

10^

The relations which obtain for silver with its infinitesimal
solution-tension, might not exist for metals with a high solu-
tion-tension, and especially for metals with such enormous solu-
tion-tensions as those which stand near the head of the first col-
umn. It is, therefore, very desirable to determine the solu-
tion-tension of some metal high in the tension series, in differ-
ent solvents, and see what variations obtain.

We have succeeded in doing this in the case of zinc im-
mersed in an alcoholic solution of zinc chloride. The elec-
tromotive force of the element,

N N

TTJ TIT

. Zn— ZnCl— ZnCl,— Zn,

(Alcoholic) (Aqueous)

was measured by Kahlenberg^ and found to be 0.195 volt,
the alcoholic pole being positive. To determine the solution-
tension of the zinc in the alcoholic solution, we must know
the dissociation of the one-tenth normal solution of zinc chlo-

1 J. Phys. Chem., 3, 400.

2 Ibid., 3, 3S9.

402 Jones and Smith.

ride in ethyl alcohol. This will be seen from the following
equation for the electromotive force of the above cell :

-. = ^^(log^-log^),

in which P^ and P^ are the solution-tensions of zinc in the
alcoholic and aqueous solutions, respectively, and p^ and p,
the osmotic pressures of the zinc ions in the alcoholic and
aqueous solutions.

In the above equation P^ and p, are known, n was meas-
ured, and we must therefore know p, before we can calculate

We have a method for measuring approximately p, — the
dissociation of zinc chloride in ethyl alcohol — at a concentra-
tion of one-tenth normal. The boiling-point method which
has been improved and used by one of us' to measure disso-
ciation, was employed.

The zinc chloride which we used was prepared by distilling
a fine sample of zinc chloride in a hard-glass tube through
which a stream of hydrochloric acid was passed. This was
done to remove any oxychloride which might be present, or
which might be formed when the last traces of water were be-
ing removed from the zinc chloride. The redistilled zinc
chloride was allowed to cool in the gla.ss tube in the stream of
hydrochloric acid gas, and was then removed to a desiccator
and kept over phosphorus pentoxide. The salt thus quickly
lost every trace of the acid gas which clung to it when it was
removed from the glass tube.

The ethyl alcohol used was dried first over lime, and after
distillation was kept over copper sulphate for several months.
A solution of zinc chloride in ethyl alcohol of the strength de-
sired (y^(j) was prepared, and with this the dissociation of the
solution was measured.

The mean of six determination showed that a tenth-normal
solution of zinc chloride (by volume) in ethyl alcohol is dis-
sociated 6.5 per cent. It seems probable from our determina-
tions that this is correct to within i per cent. Substituting
this value of pj in the equation :

1 Loc. cit.

Ziyic in Ethyl Alcohol. 403

7t = 0.02Q ( lOo^ — ~ 10°: — =■ I ,

and solving for log P^, we have :

log P, = ____-|- log P^ + log p, — log p,.

P, = 1.9 X io'\

We have calculated the solution-tension of zinc in an alco-
holic solution of zinc chloride by a second method. Kahlen-
berg' measured also the absolute electromotive force of the
alcoholic side of the above element, by means of a standard
electrode, and found it to be 0.327 volt.

The equation for the potential upon the alcoholic side of the
cell is :

Tt rr 0.02Q log — -,
"p.

the symbols having the same significance as in the last equa-
tion.

log P, = -^^^^ + log p,.
^ ' 0.029

P, = 2.7 X lo"'.

The values of P^, calculated by the two methods, agree as
well as could be expected. Hence the solution-tension of zinc
in ethyl alcohol eqtials, approximately, the solution- te?isio7i in
water divided by lo'.

In determining the value of p, by the boiling-point method,
the assumption is made that zinc chloride in ethyl alcohol is
dissociated to the same extent at the boiling-point of the
alcohol, as at ordinary temperatures. This assumption can-
not be far from true, since it was shown several years ago^
that dissociation in water, as measured by the freezing-point
method at 0° C, agrees very closely with the dissociation as
measured by the conductivity method at iS^ C.

Chemical Laboratory,
Johns Hopkins University.

1 Loc. cit.

2 Ztschr. phys. Chem., ii, 529 ; 12, 639.

Contribution from the Kent Chemical Laboratory of the University of Chicago.

NOTES ON LECTURE EXPERIMENTS TO ILLUS-
TRATE EQUILIBRIUM AND DISSOCIATION.

By Julius Stieglitz.
/. Equilibrium and Gaseous Dissociation.

The prominent r61e pla}^ed by conditions of ionic equilib-
rium in solutions of electrolytes makes a thorough presenta-
tion of the subject desirable in college courses on general
chemistry, and a still more exhaustive study necessary in
analytical chemistry. The relative size of the dissociation
constants and the influence exerted on the condition of equilib-
rium by increasing the concentration of one of the dissocia-
tion-products are the points most emphasized. It seems de-
sirable to impress these two points on the mind of the student
at the stage where the general subject of equilibrium and dis-
sociation is first dealt with, which may, perhaps, be done best
in connection with the question of gaseous dissociation,
raised, for instance, by the vapor-density determinations of
phosphorus pentachloride, ammonium chloride, etc. The fol-
lowing two lecture experiments with phosphorus pentabro-
mide and phosphorus trichlordibromide' were developed to
illustrate the second of the two points mentioned, the effect of
an increase of the concentration of one of the products of gas-
eous dissociation. The contrast of the tubes showing the dis-
sociation of the pentabromide and the trichlordibromide at 50°
may also serve to demonstrate the first point, the influence of
the relative size of the dissociation constant or the relative
ease of dissociation, in default of substances for which the
constants for gaseous dissociation have actually been deter-
mined and which could at the same time be used for lecture
experiments in general chemistry.

Phosphorus Pentabromide and Phosphorus Tribromide.

The effect of an excess of phosphorus tribromide on the dis-
sociation of the pentabromide is shown by comparing the in-

1 vide Wurtz's work on phosphorus pentachloride, Ber. d. chem. Ges., 3, 572.

Equilibrium and Dissociation. 405

tensity of the color of the bromine vapor in two tubes charged
as follows ■}

Sealed bulbs containing 0.029 gram bromine (i molecule)
and 0.058 gram phosphorus tribromide (a little more than i
molecule) were placed in a piece of thick-walled tubing''
closed at one end, the tube drawn out to a capillary, the air
exhausted to 30 mm. pressure, and the capillary sealed rather
close to the tube, the rest of the capillary being bent into a
loop. The tube charged in that way was 18 cm. long and had
a capacity of 40 cc. By vigorous shaking the bulbs contain-
ing the bromine and tribromide were broken. A second tube
of the same size was charged with 0.029 gram bromine (i
molecule) and 0.45 gram tribromide (9 molecules). A few
coils of lead or fuse wire were wound around the lower part
of the tubes.

The tubes, thus prepared, are suspended side by side in a
tall beaker of water by means of the glass loops at the upper
ends. A glazed white porcelain tile placed in a slightl}^ slant-
ing position behind the beaker makes the comparison of the
colors easier. On heating, at 50° only a very slight color ap-
pears in the first tube (see below, phosphorus trichlordibro-
mide), none in the second tube. From 80" to 90° the disso-
ciation has progressed to the most favorable stage for com-
parison ; the first tube shows a more intense color than the
second one, which contains the excess of the tribromide, the
color of the former being reddish-brown and opaque while that
of the latter is reddish-yellow, through which the white of the
tile can still be seen.

Phosphoriis Trichlordibromide and Phosphorus Trichloride.

The difference in color between the two tubes in the above
experiment will be sufficiently evident to most students, but
perhaps not quite marked enough for the student whose judg-
ment is still to be developed. By using phosphorus trichlor-

1 Instead of using phosphorus pentabromide it was found more convenient to
use the tribromide and bromine in molecular proportions, weighed in small bulbs
blown at the end of capillaries. The weighing out of the exact quantities required
was rapidU' accomplished by weighing a bulb both on an analytical balance and on
rougher scales. When by means of the latter the amount required in the bulb was
very nearly adjusted, the final weighings were made on the sensitive balance, the
bulb being placed in a pair of weighing tubes fitting closely over each other.

2 The ordinary tubing used for heating solutions under pressure.

4o6 Stie glitz. '

dibromide' with and without an excess of the trichloride
greater differences in color were obtained, putting the student
in question out of temptation to rely less on his own judgment
than on the demands of theory.

Tubes of the same size (40 cc. capacity) were charged as
above, respectively with 0.029 gram bromine (i molecule)
and 0.029 gram phosphorus trichloride (0.004 gram more than
I molecule) and with 0.029 gram bromine (i molecule) and
0.155 gram phosphorus trichloride (6 molecules) ; the air
pressure in the tubes was reduced to 27 mm. At 40°-55°the
difference in the colors of the two tubes is most marked, the
first one being dark-brown and the second one yellow.

The influence of the relative size of the dissociation con-
stants or the relative ease of dissociation of phosphorus penta-
bromide and of phosphorus trichlordibromide is shown by
comparing, at 50°, the colors of the tubes containing these
substances (the first tube in each series) ; the former is found
to be nearly colorless, while the latter is dark-brown, showing
the greater tendency of the trichlordibromide to dissociate.

//. Equilibrhim and Electrolytic Dissociation. Ammonium

Hydroxide and Sohttions of Am,m,onium Salts (Ammo-

nitim, Io7is) .

Loven^ has shown that the characteristic action of ammo-
nium salts in preventing the precipitation of magnesium hy-
droxide by ammonium hydroxide is simply the result of equilib-
rium changes. The most important of these is the gradual
suppression of the hydroxyl ions of the ammonium hydroxide
by greatly increasing the concentration of the ammonium ions
on adding the easily dissociating ammonium salts, equilib-
rium being established according to

NH^ X 0H'= k X NH^OH.'
This important action of ammonium salts can be demonstrated

1 Phosphorus trichlordibromide dissociates at 35° into phosphorus trichloride
and bromine (Michaelis : Ber. d. chem. Ges., 5, 9).

2 Ztschr. anorg. Chem., 11, 404.

3 At the same time NH4OH = k' X NH3 X H5O ; the symbols are used to designate
concentrations.

Equilibrium ayid Dissociation. 407

very simply by the following experiment' withphenolplitlialein ;
after producing a brilliant red color by adding a drop or two
of dilute ammonia to each of two beakers containing water
and a little phenolphthalein, a few drops of a rather concen-
trated solution of ammonium chloride are added to the con-
tents of one of the beakers. The color fades to a scarcely
perceptible pink and then disappears.

As ammonium chloride is liable to have an acid reaction
ammonia may be added to its concentrated solution until a
little of it can be shown to give a faint but distinct pink color
to a solution of phenolphthalein — proving that it certainly con-
tains no free acid. On adding a few drops of this somewhat
alkaline ammonium chloride solution to the crimson solution
produced by a drop of ammonia, the red color instantly gives
way to a faint pink. This form of the experiment seems to
be the most convincing and striking one : the adoption of
either form must depend on the advancement of the class.

It may be added that ammonium chloride solutions which
react distinctly alkaline to litmus (see below) make the red
color produced by the action of ammonia on phenolphthalein
disappear completely. These experiments are, of course,
based on the well-known lack of sensitiveness of phenolphtal-
ein towards hydroxyl ions.

With analytical students the experiment just described may
well be followed by a parallel experiment with litmus solu-
tion : it is best to use four beakers containing neutral litmus
solution ; the first is used to preserve the original tint ; to the
second 5 to 10 cc. of a concentrated ammonium chloride solu-
tion are added, which, to avoid the suspicion of acidity, has
been made very slightly alkaline ; the color in this second
. beaker changes distinctly towards a bluer violet. The other
two beakers are each treated with a drop of quite dilute am-
monia, which gives to each a pure-blue tint, and to one of
them 5-10 cc. of the solution of ammonium chloride are added,

1^ The experiment may serve as a particularly simple and pretty illustration of
ionic equilibrium in general and as a basis for the discussion of the use of ammo-
nium salts with ammonia in many important reactions of analytical chemistry, e.^.,
in preventing the precipitation of magnesium hydroxide and many analogous hy-
droxides, in facilitating the quantitative precipitation of aluminium hydroxide, etc.
The simpler form is preferable for general chemistry classes, the use of the slightly
alkaline ammonium chloride is more instructive for advanced students.

4o8 Crane.

the color reverting to violet. The change is perfectly plain ;
but, as litmus is more sensitive to hydroxyl ions than phenol-
phthalein, the change is not as pronounced as when the latter
is used.

Kiister' has described a lecture experiment to show, by
means of methyl orange, the analogous suppression of the
hydrogen ions of acetic acid by adding acetate ions in the
form of an acetate {e. g. sodium acetate), according to

CH3CO; X H = k X CH3C0,H.

In consequence of hydrolysis sodium acetate reacts alkaline
and the experiment in its original form is, perhaps, open to
this objection. A convincing and striking proof of its cor-
rectness may be given b}^ using a solution of sodium acetate
which, to prevent the suspicion of alkalinity, has been made
very slightly acid, giving with methyl orange the well-known
reddish-brown hue of beginning acidity. On adding even 2
or 3 drops of this slightly acid solution to a beaker of a
methyl orange solution, colored an intense red by a drop or
two of acetic acid, the red color is at once replaced by the
brown hue of lesser acidity.

Chicago, February 19, iqoo.

A CONTRIBUTION TO THE KNOWLEDGE OF
TELLURIUM.

By F. D. Crane.2

The rise of the electric refining industry has placed within
reach the dross which is produced in large quantities in the
final purification of the precious metals, and it is with tel-
lurium from this source that the work here described was
done. The process by which the by-product is obtained has
been described by C. Whitehead.^ It contains much silica,
tellurium mostly as tellurite, wdth a little tellurate due to the
drying, and some selenium, antimony, arsenic, copper, and

1 Ztschr. Elektrochem., 4, no.

2 From the Author's dissertation for the degree of Doctor of Philosophy, sub-
mitted to the Board of University Studies of the Johns Hopkins University, June,
1898. The work described was undertaken at the suggestion of Professor Remsen
and carried on under his supervision.

8 J. Am. Chem. See, 17, 849.

Tellurium. 409

other metals. Varying quantities of iron and aluminium and
a relatively large quantity of potassium are present.

Extraction of Tellurium.

From this white substance the tellurium is readily ex-
tracted by repeated leaching of the powdered material with
strong commercial hydrochloric acid. Heating the acid does
not appear to be of much advantage. The best results are
obtained when large quantities of it are used.

In order to filter the slimy mud at all rapidly, a good pump
and as large a filtering surface as possible, should be used.
To make such a surface a 3.5 cm. Witte plate is put in a large
funnel and covered with a rather thick layer of glass beads.
On this is placed a layer of asbestos in the usual manner.
This device allows lateral passage of the filtrate, and gives a
much larger effective surface than the combined area of the
holes of a plate alone.

The bright- yellow hydrochloric acid solution which is ob-
tained is evaporated to a convenient consistency, depending
on the use to which it is to be put. It contains considerable
quantities of the metals which occur as impurities as well as
the tellurium and selenium.

Precipitation of Tellurium.

Since the work of Berzelius the use of sulphur dioxide as a
precipitant of tellurium has ordinarily been advised, although
it has been known equally long that the action is never quite
complete and that traces of other metals, as well as all the se-
lenium, come down also. Its exceeding convenience, how-
ever, was a strong reason for its use in the present instance
for at least the preliminary precipitation. It was found that,
in all probability, the main reason for the incompleteness of its
action is the very rapid increase in the ratio of acid to un-
precipitated tellurium in the solution, two-thirds of this being
due to the hydrochloric acid set free, and one-third to the sul-
phuric acid formed.

If these could be removed the precipitation should go on.
Evaporation sufficed for the hydrochloric acid, and an addi-

4IO Crane.

tional quantity of tellurium was obtained, but the increase of
the sulphuric acid soon stopped the reaction.

The practical removal of the acids by neutralization was
then tried, and it was found that the addition of an alkali or
alkali carbonate resulted in a renewed precipitation. At this
point Mr. R. ly. Whitehead advised the use of acid sodium
(or potassium) sulphite ; and his suggestion was thencefor-
ward followed.

But even with this very eflScient reagent the action in the
cold is never quite complete. It was found that, if a solution
in which neither more acid sulphite nor more hydrochloric
acid, added to decompose some of the excess of acid sulphite
already present, will produce a further precipitate, is heated
to boiling, there is then a further precipitation without any
addition of reagents.

It is better to remove the first precipitate before boiling, as
the action is then more readily seen. This new precipitate
gives the qualitative reactions for tellurium, and differs from
the first precipitate only slightly in tint. Its formation is prob-
ably due to the decomposition of some alkali tellurate at first
formed through mass action. By this means, then, the tellu-
rium was obtained, mixed with selenium and a little of the
other impurities.

Precipitation of Tellurium by Magnesium.

In devising a method for the more accurate estimation of
tellurium it was found that metallic magnesium would com-
pletely precipitate tellurium from a solution of the tetrachlo-
ride in hydrochloric acid. The excess of hydrochloric acid
should be as small as possible, and a slight excess of magne-
sium should be added. This latter may be destroyed by vig-
orous boiling, when it decomposes the water ; the magnesium
hydroxide is then removed by acidifying very slightly with
acetic acid. The well-washed tellurium precipitated by this
method seems to be less easily oxidized.

Detection of Tellurium.

The apparent completeness of the action of acid sodium
sulphite led to the idea that it would detect small quantities

Tellurium. 411

of tellurium and do this more rapidly and efficiently than
former methods. To test this, a weighed portion (0.107
gram) of tellurium was dissolved in hydrochloric acid by the
aid of as little chlorine gas as possible, and the solution gently
heated to expel any excess of chlorine. It was then diluted
with a little hydrochloric acid and finally with water to 500 cc.
Ten cc. of this solution gave a marked precipitate. Ten cc.
were diluted to no cc, and as the same quantity of this also
gave a strong reaction, the dilution was repeated in a similar
manner. An effective surface of about one-half a square cen-
timeter of white filter-paper was used to collect the precipi-
tate, and on this the layer of black tellurium was plainl}- vis-
ible ; the amount present per cubic centimeter of solution being
0.00000214 gram, and the total quantity used being 0.0000214
gram. The presence of tellurium was still discernible when
the dilute solution contained only 0.000000214 gram per cubic
centimeter and there was present but 0.00000214 gram.

It appears probable that this limit is due simply to the fact
that we have here nearly reached the physiological limit of
seeing black on white.

Detection of Selenium .

Mr. Edward Keller has recently called attention to the pre-
cipitation of selenium by ferrous sulphate,' and this reaction
was tested in like manner, 0.1139 gram of selenium being
weighed out, dissolved, and diluted. The precipitated sele-
nium colored the paper the bright, characteristic red
when the dilution was 0.00000207 gram per cubic centimeter,
ten times that quantity being used. And at a dilution of
0.000000207 gram per cubic centimeter the precipitate from 10
cc. was more easily seen than that of tellurium at about the
same dilution.

Furthermore, the precipitation of selenium at a dilution of
0.00000207 gram per cubic centimeter is independent of the
presence of a little more than one hundred times as much
tellurium as tetrachloride.

Precipitation of Tellurium, by Ferrous Sulphate.
Mr. Keller' states that ferrous sulphate does not precipitate

1 J. Am. Chem. Soc, 19, 771. 2 Keller : Loc. cit.

412 Crane.

tellurium. The statement is evidently made with respect to a
solution of the tetrachloride in hydrochloric acid, and, if only
the tetrachloride is present, it is quite true. Ferrous sul-
phate, however, precipitates tellurium from a solution of the
tetrachloride in hydrochloric acid if it has been boiled vigor-
ously for some time, the evaporating acid being replenished ;
or if it is boiled, heated, or remains for some time in contact,
with tellurium.

This seems to be due to the presence of teLurium dichlo-
ride. But tellurium dichloride, according to Rose,' breaks
down in the presence of acids into tellurous acid and tellu-
rium. To test this the two chlorides of tellurium were made,
first by the direct action of chlorine on tellurium, and then by
the action of this tetrachloride on the proper amount of tellu-
rium. The solution which was obtained by treating the di-
chloride in the cold with hj^drochloric acid gave, to a slight
extent, a black precipitate with ferrous sulphate, and a solu-
tion made with the hot acid gave it much more markedl5\

A mixture of the two chlorides treated with the acid gave a
very decided precipitate, and a solution of the dichloride in a
strong solution of the tetrachloride in hydrochloric acid, gave
it most strongly of all. In all these experiments the known
decomposition of the dichloride into free tellurium was promi-
nent and evidently nearly in theoretical quantity, so all the
solutions were well filtered before the ferrous sulphate was
added.

The actual mass of the precipitated tellurium is small in
comparison with the quantity present as chloride, but the deep
black color and the very fine state of division produce a very
marked effect. The black precipitate collects and settles
after a time, and seems to diminish in bulk.

This is no doubt the same sort of change as that which oc-
curs in tellurium precipitated by sulphurous acid or acid sul-
phite, and that is probably akin to the changes in precipitated
selenium and tellurium when heated.

Furthermore, a boiling solution of tetrachloride in hydro-
chloric acid will dissolve a little tellurium. In order to have
the action complete, there must be but little of it, and that in

1 Rose : Pogg. Ann., 21, 443.

Tellurium. 413

a state of fine division. This action may account in part for
the apparent diminution of the precipitate just mentioned.

It is hard to keep a concentrated solution of the chloride in
a condition in which it gives no precipitate v^^ith ferrous sul-
phate, but it may be quickly brought to such a condition by
passing through it a few bubbles of chlorine, the excess of
which is soon lost by allowing the solution to stand open a
short time.

Purification of Tellurium.

The purification of tellurium in quantity appeared to be a
question of getting rid of selenium on the one hand, and of
various more metallic elements on the other. And it seemed
advisable to do this as simply as possible in view of the un-
certainty as to the individuality of the substance.

Suspicion has been cast, at various times, on all methods
which require repeated evaporations, distillations, or crystal-
lizations, or in which nitric acid must be removed by pro-
longed heating. Further, it has been directly alleged that
distillation in hydrogen gave a product with a lower relative
weight. '

The method of Keller works well for selenium, if precaution
is taken to prevent a reversal of the action through the mass
action of the tellurium tetrachloride on the precipitated sele-
nium, which will be referred to below. But it has the great
disadvantage of burdening the solution with iron salts and
sulphuric acid , which latter always makes the precipitation of
tellurium more difl&cult.

The method of Stolba,^ which depends on the reduction of
a tellurate in alkaline solution by boiling with glucose, which
reduction is claimed to begin and be completed before a simi-
lar action with any selenite present, appears to work as de-
scribed. But in the presence of the excess of glucose and its
decomposition products it is very hard to determine the limits
of the reactions. Pure tellurium is unquestionably formed at
first, but the uniformity of the reaction remained in doubt.
This process could doubtless be made to work well, but it was
not used, since that to be described seemed simpler.

1 Bauner : J. Chem. Soc, 55, 392.

2 Stolba : Jahresbericht, 1873, 214.

414 Crane.

As only a small fraction of the more metallic elements was
carried down by the tellurium, it seemed probable that several
precipitations would remove practically all of these. Conse-
quently, it was required to repeatedly convert the precipitated
tellurium into the tetrachloride. The direct action of gaseous
chlorine on dry tellurium is very rapid, but much heat is
evolved, enough, in fact, to volatilize a part of the chloride
unless the process is carried on quite slowly. The action of
gaseous chlorine on tellurium suspended in atrong hydro-
chloric acid is, on the other hand, quite slow ; and rapidly be-
comes slower as the quantity of dissolved chloride increases,
and is very slow if the tellurium is at all compact.

It has long been known that tellurium is much more metal-
lic than selenium, and that selenium is the first to be precipi-
tated by sulphur dioxide. In fact this method has been sug-
gested for their separation. Now it seemed probable that, if
the mixed precipitate could be subjected to the action of nas-
cent chlorine, by being made the positive pole of an electro-
lytic cell containing hydrochloric acid, not only would the tellu-
rium be rapidly converted into the chloride at a low tempera-
ture, but also the more metallic tellurium would be first
attacked, to the practical if not total exclusion of the sele-
nium.

Preliminary trials on a small scale having shown the rapid
action of the nascent chlorine, a larger apparatus was made.
This consisted of a 750 cc. funnel with the stem ground square
off. In the bottom of the funnel portion was placed a button
of commutator carbon about 2.5 cm. in diameter, to whicli
was soldered a small brass nut.

The button was sloped to fit the funnel and jacketed with a
doubled rubber tube. Through the stem of the funnel was
passed a heavy copper wire, threaded at both ends, and hav-
ing on the lower end a small nut. The upper end of this
wire was screwed into the nut on the button, and the button
then drawn down tight by the lower nut acting against the
lower end of the funnel stem. This formed the positive pole,
the current being taken in on the wire.

The negative pole was formed of a sheet of thin copper of
some 30 sq. cm., which was soldered to a convenient wire.

Tellurium. 415

This pole was never in the acid but a moment before the cur-
rent was on, and was removed at once when it was off, so that
it was not attacked by the acid. To prevent the deposition
of tellurium, it was inclosed in a little porous cell which was
hung on the edge of the funnel. A small automatic drip
supplied pure hydrochloric acid just fast enough to keep the
surface of the liquid in the cell about 0.5 cm. above that in
the funnel, so that there was always a flow of pure acid
through the cell away from the negative pole. It was ex-
pected that the sloping sides of the funnel would keep the un-
attacked tellurium always at the bottom, but as the specific
gravity of the solution increased, the solid did not sink rap-
idly enough, so a glass rod, mechanically turned, was put in
to act as a stirrer. When somewhat heated from the passage
of the current, this arrangement had a very constant resist-
ance of a little more than half an ohm, and, with the current
employed, used about 9 amperes.

Practically, every trace of the chlorine liberated was ab-
sorbed, and consequently the speed of solution depended di-
rectly on the current. The first charge of the cell was not
quite all dissolved when it became necessar}- to stop the ac-
tion over night, and the entire contents of the cell were re-
moved to another vessel. At the same time a portion of the
liquid was taken out and tested for selenium, which was found
to be present. Evidently the tellurium was not exclusively
or primarily attacked, as some of it visibly remained. The
next morning this test was repeated, and no selenium was
found. And the reddish color of the selenium indicated that
it had been precipitated. This electrolytic chlorine method
of solution is yery efficient and has the marked advantage of
adding no foreign substance. It is the more rapid, of course,
the more finely divided the tellurium.

Separation of Selenium by Tellurium,

Further experiments showed that if to a mixture of sele-
nium dichloride, and tellurium tetrachloride dissolved in
hydrochloric acid, tellurium is added, or a portion of the tellu-
rium precipitated, and the mixture allowed to stand for some
time, or better and much more expeditiously, boiled, all the

41 6 Crane.

selenium will disappear from the solution, and will be found
in the sediment, with the excess of tellurium. If the action
takes place at the ordinary room temperature, the selenium
can easily be seen on account of its color, but if heat is used
the well-known change to the black form will occur, and it
cannot be distinguished from the tellurium.

It can be readily detected, however, by filtering off the
black residue and dissolving it in a little hydrochloric acid by
the aid of chlorine, when the selenium may be again precipi-
tated. If this reaction is carried on upon a microscope slide,
it can be well seen and makes a very pretty effect when mag-
nified to about 80 diameters.

On the large scale it is preferable to heat the solution of
mixed chlorides gently just below the boiling-point, and to
have the tellurium in as fine a state of division as possible
and well mixed with the fluid. To attain both these ends it
is advisable to precipitate some of the tellurium, either by
leading in a little sulphur dioxide, or adding a little acid sul-
phite. The turbid liquid which results does not clear for
some time by settling.

That this process is complete is shown by the fact that it
not only removed selenium from tellurium tetrachloride solu-
tions so completely that none could be detected by the ferrous
sulphate test, but also removed selenium completely from a
solution of selenium dichloride in hydrochloric acid, previously
precipitated tellurium being employed. In this experiment
tellurium is found in solution which shows conclusively a re-
placement or an exchange.

If, on the other hand, selenium is gently heated in a solu-
tion of tellurium tetrachloride for some hours, the addition of
ferrous sulphate to the filtered fluid will show that a very
small part of the selenium has gone into solution. This
minute amount may be entirely removed by the treatment
with tellurium. This seems to explain the observation that
in working with quite large quantities of the mixed chlorides
in solution, the action of ferrous sulphate even in excess did
not seem to be quite complete if a few hours elapsed before
the precipitated selenium was filtered off. But the solution
could not be made to take up selenium if there was a little

Telhirium. 417

tellurium present, and it was kept well stirred. The phe-
nomenon appears to be, to some extent at least, one of mass
action.

In using this process for the removal of selenium, the pre-
cipitate, containing the excess of tellurium, is filtered off and
redissolved, either by nascent chlorine or by conducting into
it, suspended in hydrochloric acid, a stream of that gas. The
selenium is then easih' removed by ferrous sulphate and the
tellurium by acid sulphite. It is well to avoid the use of
nitric acid.

The Further Purification of Telluriuvi.

The logical sequence to boiling the mixed chlorides with
tellurium in order to precipitate selenium or any less metallic
elements was to boil the precipitated tellurium with a re-
served portion of that solution from which it had been ob-
tained, so that any more metallic elements which might have
been carried down would be dissolved, and precipitate an
equivalent quantity of tellurium. This was done, although
several precipitations in the ordinary manner seemed to have
already removed those traces of metals which have been pre-
viously noted as occurring in the crude material.

The tellurium prepared in this manner has the usual ap-
pearance and reactions, and could be completely distilled in a
current of hydrogen, leaving only a slight residue of carbon-
aceous material probably derived from the filter-papers. It
was noted that there was very little tendency to form hydro-
gen telluride with pure, dr}^ hydrogen.

This process should tend to separate the suspected homo-
logue of tellurium of greater relative weight, and although no
definite indications of such a substance have been met with
up to the present, work will be continued along this line if
time and opportunity are found.

Determination of Tellurium.

There has never been any sure method of determining tel-
lurium. Most observers have either determined other ele-
ments in the tellurium compounds, or precipitated the tellu-
rium, treated it with nitric acid, and converted the compound

4i8 Crane.

thus formed into the dioxide b}^ heat. This has been the
most exact method.

But Brauner' notes the brown decomposition which Staud-
enmaier" had observed, and further claims that the nitric acid
is not wholly driven off before a part of the dioxide is vola-
tilized. A method of avoiding the brown color has lately
been given b}^ Norris and Fay,'' but nothing is said as to the
removal of the nitric acid, and there is visible volatilization.
But gravimetric determinations by the method about to be de-
scribed showed that the dioxide prepared b}^ that method was
quite pure. However, it is doubtful if nitric acid can be re-
moved without some volatilization.

No volumetric method which does not require a correction
term, with the exception of that of Norris and Fay, has been
devised. The objections to the direct precipitation and
weighing of the tellurium were alleged to be two ; that it was
not possible to precipitate all the tellurium from an acid solu-
tion, and that after precipitation it was oxidized so much in
drying that the results were variable.*

In view of the extreme delicacy of the acid sodium sulphite
as a test for tellurium, it seemed advisable to try it as
a precipitating agent in quantitative work. There is no doubt
that free acid does prevent the complete action of sulphur di-
oxide, but there is no evidence that neutral alkali salts in
solution do this, if the solution is heated ; at least qualitative
experiments failed to show such an action. So it is only
necessary to add enough acid sulphite to give up soda to the
acids present and set free. A slight excess of sulphite does
no harm, and an excess of sulphur dioxide is readily re-
moved. After the acid sulphite has been added, it is advisa-
ble to let the mixture stand for a time, usually, for conve-
nience, over night, as the precipitate seems to be in better me-
chanical form when this is done. But the action may be com-
pleted at once by heating. At any rate, the liquid with the
precipitate still in it should be raised to the boiling-point for
a short time. This is to gain two ends : to insure the total

1 Brauner : Loc. cit.

2 Staudenmaier : Ztschr. anorg. Chetn., lo, 206.
8 Norris and Fay : This Journal, 20, 278.

* Brauner : Loc. cit. ; Norris and Fay : Loc. cit.

Tellurium. 419

precipitation of the tellurium, which is never quite complete
in the cold when large amounts are being handled (as has
been noted) ; and to cause some definite but undetermined
change in the precipitate. As a result of this it becomes
much easier to filter and wash, and less liable to oxidation.
This change, as has been said, seems to be like the long-
known change in selenium. It is hard to describe, but
easily recognized, although it consists only of the merest
change in tint and a difference in the manner in which the
precipitate settles. The precipitate is then collected on a
Gooch filter and very thoroughly washed, care being taken that
it always shall be covered with water. If speed is more requi-
site than exactness, it may now be pumped as dry as possible,
quickly dried in an air-bath, and weighed. It will oxidize to
some extent, but by no means seriousl5\ The oxidation can
easily be detected and the extent of it quite accurately judged
by removing the precipitate with the filter surface, after
weighing, and putting it in a beaker on a white surface, or in
an evaporating dish and moistening it with a few drops of
strong hydrochloric acid. A yellow tint of dissolved chloride
appears at once only if oxidation has occurred, as unoxidized
tellurium does not color hydrochloric acid. But if this prepa-
ration is allowed to stand, a color will appear, as the air acts
readily on the acid mud. To determine how far this color
could be used as a criterion of the presence of oxide and its
amount, a weighed portion, 0.0068 gram, of pure tellurium
tetrachloride was dissolved in strong hydrochloric acid and
diluted. The yellow color of a layer 0.25 cm. thick was
plainly visible when 0.00013 gram of tetrachloride was present
in each cc.

To see if the method without special precautions in drying
was even nearly correct, portions of a pure precipitated tellu-
rium in which very little oxidation had occurred were
weighed out, dissolved in a little hydrochloric acid by the aid
of chlorine gas and treated as stated above.

Taken.

Found.

Gain.

Recovered.

Gram.

Gram.

Gram.

Per cent.

0.1768

0.1779

O.OOII

100.6

0.1285

0.1289

0.0004

100.3

420

Crane.

Probably practice in its use would make this method exact
enough for all practical purposes. From the article by Mr.
Keller already referred to, it appears that no special precau-
tions in drying are used at the works of the Baltimore Elec-
tric Refining Company.

Device for Filtering.

To prevent, if possible, any oxidation, the filtering crucible
was enclosed in a cylinder through which dry, pure hydrogen
which had just been passed over hot platinized asbestos was
slowly drawn under slightly diminished pressure. The device
was so arranged that it was not necessary to remove it from
the filter flask, and a J-tube in the pump connection was
joined to a mercury safety-valve by which both the pressure
and flow were regulated. The cylinder and its contents were
heated by jacketing them with 'a strong solution of calcium
chloride, after the manner of a hot-water funnel, and this bath
was also used to warm the entering stream of hydrogen.

This arrangement prevents oxidation as far as can be de-
tected by the coloration of hydrochloric acid, and as the re-
sults seem quite constant, it probably does not occur to a
measurable extent. There is no evidence to show that tellu-
rium, which has been boiled with water, can decompose water

Tellurium. 421

in the presence of hydrogen, so that the essential thing is to
have pure hj'drogen.

The Method. — The entire process is as follows : The given
compound is so treated that the tellurium is in the form of
the tetrachloride, avoiding, if possible, the use of nitric acid,
and as little hydrochloric acid as possible being used. The
solution is now diluted with water, but not to such an extent
that a W'hite substance appears, although a little of this seems
to do no harm. The objection to a larger quantity is me-
chanical, the interior of the flocculent masses seeming some-
times to be unattacked by the sulphuric acid. A solution of
acid sodium or potassium sulphite is now added. It should
be moderately concentrated, and the quantity should be such
as to neutralize nearly exactly the acids present and set free
by the base of the reagent. The excess of sulphur dioxide
will escape harmlessly, but anything more than a slight ex-
cess of the acid sulphite is detrimental. The mixture, which
has turned dark, has been gently agitated during these
manipulations ; it is now diluted to about 50-75 cc. and al-
lowed to stand for a time as the precipitate thus seems to form
more evenly. But it may be warmed at once.

If too much sulphite has inadvertently been added, the pre-
cipitate should be decanted and reserved, and the precipitate
washed once or twice and the decanted wash-water added to
the other, and all this passed through the weighed filter later.
The reason for this is that it is very hard to decant without
getting some of the precipitate over, although it may remain
invisible until it blackens the filter. If time is not a consid-
eration, this decantation process may well be emploj^ed in all
cases.

The precipitate, in about 75 cc. of water, is now gently
warmed, being stirred with a glass rod tipped with a bit of
rubber tube, both to prevent " bumping" and to detach those
portions which at times form a very marked ' ' mirror' ' on the
sides of the vessel ; it is allowed to boil rapidly for a moment
or two, and then set aside. A little water may be added, as
it aids the settling. The tellurium, which has changed in
appearance, should settle very quickly. If it does not, it
may be boiled a little more, but it is to be noted that differ-

422

Crane.

ences in the concentration of the solution in which the pre-
cipitation took place may markedly influence the character of
the precipitate.

The amount of material taken should be such that the tellu-
rium will form a rather thin layer in the filter even while still
wet. The precipitate is now^ filtered through a weighed fil-
ter, care being taken to keep it always covered with water,
and well washed, and since there is no reason to suspect any
action of the water, the washing should be thorough.

After the washing is completed, the hydrogen supply is con-
nected at once, the last water being followed through the fil-
ter by the hydrogen. But no effort need be made to displace
the small amount of air in the cylinder.

The temperature of the calcium-chloride bath is now quickly
raised to about iio° and kept there till the tellurium is dry.
This must be judged from its appearance.

The filter is then removed to a desiccator, and, when cool,
weighed. There is no tendency to oxidize rapidly in the air
if thoroughly dry. The main danger to be avoided is the ac-
cidental access of air to the wet tellurium.

Some of the results obtained by this method are as fol-
lows :

Tellurium Dioxide from the Nitrate, Te := i2j.6] O = 16.

Taken.
Gram.

Found.
Gram.

Required.
Per cent.

Found.
Per cent.

0.1047
O.II3O

0.0838
0.0904

79-95
79-95

80.03
80.00

ium Tetrachloride Distilled

in Carbon Dioxide, CI =

Taken.
Gram.

Found.
Gram.

Required.
Per cent.

Found.
Per cent.

0.3879
0.5678

0.1857
0.2717

47-33
47-33

47-87
47-85

Tellurium Oxychloride, Fused.

Taken.
Gram.

Found.
Gram.

Required.
Per cent.

Found.
Per cent.

0.62075 0.3689 59.46 59.43

Tellurous Acid, frotn the Chloride.

Taken.
Gram.

O.I 1985

Found.
Gram.

0.0862

Required.
Per cent.

71.84

Found.
Per cent.

71.92

Tellurium. 423

A Yellow Form of the Dioxide.

If a solution of tellurium tetrachloride in hydrochloric acid
which has stood for some time after the selenium has been
precipitated by ferrous sulphate and removed, or a similar
solution to which ferrous or ferric chloride has been added, is
diluted with water, a white precipitate is formed. If this is
now allowed to stand for a time, the excess of water being
decanted and replaced till it is not colored by the iron, a
heavy yellow precipitate will appear. Or if the solution is
poured directly into boiling water, the whole mass or precipi-
tate will be colored yellow. The difference in specific gravity
is so great that the remaining white substance may be almost
completely removed by washing.

This substance is easily soluble in hydrochloric acid, and
more difficultly in nitric and sulphuric acids. It is readily and
completely dissolved by alkalies and forms a colorless solu-
tion without residue. Under the microscope it is seen to consist
of more or less regular yellow crystals, of the isometric sys-
tem, octahedrons, sometimes modified by cubic faces. Among
these were traces of a white substance which seemed to cling
to the crystals. It appears to be a form of tellurium dioxide,
analyses giving the following percentages of tellurium : 79.46,
79-52, 79.51, 79-58, 79.46; calculated for TeO,, 79.95. The
discrepancy may be due to the adherent white, substance, or
to a little iron, of which a trace may be found by the ferro-
cyanide and sulphocyanide tests. To this also may be due
the yellow color, which is very persistent, not yielding to
nitric acid till the substance is all in solution, but the solution
is colorless and deposits white crystals.

Deco77ipositio7i of the Tetrachloride.
If water is added to a portion of the distilled tetrachloride
of tellurium, considerable heat is evolved and it passes into
solution as a yellow liquid. If more water is added a
curdy white substance is formed, which settles and after a
time forms the crystalline dioxide. The white substance is
tellurous acid, but the wash- water from it constantly contains
a trace of chlorine, and there may be a little of some sort of
oxychloride present. But if there is also present another

424 Crane,

metal, as iron, and particularly if antimony or arsenic is pres-
ent, there is a marked change in the character of the white
substance. It remains unchanged in water for days, and may
be washed, dried, and redissolved and reprecipitated several
times without forming the dioxide ; and no fixed amount of
tellurium was found in various samples. It appears to be a
double oxychloride, and will be the subject of further investi-
gation, if possible.

Failure to Form, Analogues of Thiosulphate.
The attempt was made to form substances analogous to
thiosulphates by boiling sodium tellurite with sulphur, sele-
nium, and tellurium, but after several hours no trace of any
action could be found.

histability of the Chlorides.
Many minor observations, as well as those already noted,
show that the chlorides of tellurium tend to pass to a
slight extent from one to the other. This is especially true
of the tetrachloride, which darkens when distilled in dry car-
bon dioxide. It is to this that the high percentage of tellu-
rium noted above is probably due. And even that distilled in
chlorine will give a slight cloud with ferrous sulphate if it
has been kept for a time.

Conclusions.

Tellurium may be easily obtained from certain wastes of
electric refineries by extracting with hydrochloric acid and
precipitating with acid sodium sulphite. Magnesium will
also precipitate tellurium, and has some advantages for quali-
tative work, and also for quantitative. Tellurium may be
detected in very dilute solutions by acid sulphite, and ferrous
sulphate is equally sensitive with selenium, and is indepen-
dent of tellurium tetrachloride. But ferrous sulphate precipi-
tates tellurium under some circumstances, probably because
some tellurium dichloride is present in the solution.

In order to avoid certain sources of suspected error, and to
add nothing but hydrochloric acid as reagent, a method of
dissolving tellurium by electrolytic chlorine was devised, and
was found to work rapidly and well.

Galle'in and Coerule'in. 425

While using this it was found that tellurium would remove
selenium. The use of tellurium for this purpose rather than
any other reagent is of advantage because it does not add any
other elements to the solution, or permit the escape of any
portion of the tellurium beyond control. This replacement
method may be extended to remove elements that are more
metallic.

Tellurium can be estimated by precipitating with magne-
sium or acid sodium sulphite, boiling, drying in hydrogen,
and weighing as tellurium.

The decomposition of the tetrachloride by water is not a
simple matter, and becomes much more complex if other
metals are present. The pure tetrachloride gives tellurous
acid which decomposes to tellurium dioxide.

Contributions from the Chemical Laboratory of Cornell University.

THE CONSTITUTION OF GAIvI^EIN AND COERU-

I.EiN.

[preliminary article.]

By W. R. Orndorff and C. IJ Brewer.

Although gallein was the first of the phthaleins discovered
by von Bae3^er, comparatively little work has been done on it
and its derivatives. Baeyer's work' established the fact that
gallein is the phthalein of pyrogallol, being formed from
phthalic anhydride and pyrogallol in accordance with the fol-
lowing equation :

C,H,03 -f- 2C,H A = C,„H, A + 2H,0.

To gallin, the reduction-product of gallein, Baeyer gave the
.composition C^^Hj^O,, while to coerulein, the product
formed from gallein by the action of concentrated sulphuric
acid, he gave the formula Cj^Hj^O,, regarding it as formed
from gallein by the loss of hydrogen.

In 1 88 1, after Baeyer had determined the constitution of
fluorescein and phenolphthalein, Buchka,"' at Baeyer's sug-
gestion, took up the question of the constitution of gallein

1 Ber. d. chem. Ges., 4, 457, 555, 663 (1871).

2 Ibid.^ 14, 1326 ; Ann. Chem. (Liebig), aop, 249 (1881).

426

Orndorff and Brewer.

and coerulein. He states that gallein, when reduced in alka-
line solution in the cold with zinc dust, gives a product, which
he called hydrogallein, having no acid properties and yield-
ing a tetracetyl derivative identical with that obtained from
gallein itself. On further reduction this hydrogallein, accord-
ing to Buchka, gives gallin, having acid properties and being
easily converted into the phthalidin, coerulin, by the action
of concentrated sulphuric acid. On the basis of this work
Buchka asserts that gallein contains a quinone group and
assio-ns to it the following formula :

C^

C,H,(OH)
! C,H,(OH)
C.H.CO

Hydrogallein formed by the reduction of the quinone group,
according to him, has the following formula :

^\

C,H,(OH),\^
C,H,(OH)/ '

C,H,CO

O '

while gallin, the further reduction-product, is a true phthalin

C^

fC.H,(OH),\^
' C,H,(OH)/ '

C.H^COOH
H

yielding the phthalidin, coerulin, with concentrated sulphuric
acid, thus :

C^

CCeH.lOHj.^^
' CeH^COH)/

C,H,COOH
H

/C,H,(OH),.
H,0 = CeH,/ I \C,H;(0H)/

OH

Galle'in and Coerule'in. 427

and gallol, on further reduction, to which he gives the for-
mula :

rC,H,(OH),\^

^ CeH.COH)/

I C,H,CH,OH

For coerulein Buchka deduces the formula :

0>

C6H,<^ p>C6H(0H)

C
O

as it gives phenylanthracene, when heated with zinc dust,
and a triacetyl derivative with acetic anhydride, just as gal-
lein gives a tetracetyl derivative, by the reduction of the qui-
none group. No direct evidence of a quinone group in gal-
lein is given by Buchka. It is assumed to be present, because,
according to him, both gallein and hydrogallein give the same
tetracetyl derivative, the identity of these products being
proved by the fact that they have the same melting-point and
give similar results on combustion analyses.

Some three and a half years ago we attempted to make hydro-
gallein and hydrogallein acetate in this laboratory by Buchka's
method, but to our surprise we found it impossible to obtain
these products. We repeated the experiment a number of
times, following Buchka's directions to the letter, but always
with the same result. The products we obtained were those
called by Buchka gallin and gallin acetate. We then found,
on looking through the literature, that Herzig' records a
similar experience. He first made gallein acetate and found
that it melted at 236°-237° C. Buchka gives the melting-
point of his product at 247°-248° C. On reducing pure gal-
lein with caustic potash solution and zinc dust, in the cold,
according to the directions of Buchka, he obtained a product
having, to be sure, the properties assigned by Buchka to hy-

1 Monatshefte fur Chemie, 13, 426 (1S92).

428 Orndorff a7td Brewer.

drogallein, but with acetic anhydride it gave 7iot gallein ace-
tate, but a product melting at 2ii°-2ij° C. , and soluble in caus-
tic potash solution without saponification, whereas gallein
acetate is only soluble in caustic potash solution after saponi-
fication. Herzig states that this product is tetracetylgallin,
which, according to Buchka, melts at 220° C, though he did
not make gallin acetate according to Buchka' s method, for the
purpose of comparing his product with it, but does call atten-
tion to the difference in the melting-points of the two prod-
ucts. Herzig was apparently not quite sure of his results,
though realizing their importance for the determination of the
constitution of gallein and coerulein, for he goes on to say :
" Buchka scheint nach seiner Beschreibung eine grossere
Menge des Hydrogalleins in der Hand gehabt zu haben, und
es konnen daher meine beiden negativen Befunde vorlaufig
die Existenz desselben nicht in Frage stellen. Allerdings
glaube ich, dass die Darstellung des Hydrogalleins nicht so
einfach ist, wie sie Buchka beschreibt und dass noch andere
Vorsichtsmassregeln nothwendig sind, die dergenannte Autor
entweder nur unbewusst eingehalten oder in seiner Arbeit zu
erwahnen vergessen hat. Ebenso halte ich es vorlaufig nicht
fiir ausgeschlosseu, dass die Identitat der Acetylproducte des
Galleins und H5'drogalleins nur auf Grund der Schmelzpunkte
ausgesprochen wurde, wahrend sie sich in Bezug auf die
Loslichkeit in Alkalien von einander so unterscheiden kon-
nen wie Acetylfluorescein von Acetylfluorescin." With this
he leaves the subject.

We had originally taken up the study of gallein with the
idea that we might be able to contribute something to our
knowledge of the constitution of the phthaleins. As, there-
fore, our results did not agree with those of Buchka on gal-
lein, we resolved to repeat this work with great care. The
Badische Anilin und SodaFabrikof Eudwigshafen am Rhein,
Germany, very kindly supplied us with all the gallein and
coerulein which we used in this investigation, and we desire
here to express our appreciation of their generosity and keen
interest in our work. Our surprise maj^ be imagined when
we found that ?iot only did Buchka'' s hydrogalle'in and hydro-
gallein acetate not exist, but that the product which he calls gallol

Gallehi and Coerulein. 429

is infadgallin. His hydrogallein, gallin, and gallol acetates
are absolutely identical in every respect.

By making very careful analyses of the esters and ethers
of gallein and gallin, we have found that the relations existing
between these two substances are best expressed by the follow-
inor structural formulas :

1=0 HO

C

COOH / \ — COOH

\/ \/

Gallein. Gallin.

The hydrogallein, gallin, and gallol of Buchka are all the
same and have the constitution given above for gallin. Gal-
lein thus appears as the phthalein of pyrogallol as originally
stated by von Baeyer, while gallin is the corresponding
phthalin. That gallein has the above quinoid formula was
shown by making a methyl and ethyl ester by boiling gallein
with the corresponding alcohol and a little sulphuric acid ;
by making the gallein triphenylcarbamate by heating gallein
with phenyl isocyanate ; and by making the colored tetra-
methyl and tetraethyl ethers, which are easily saponified by
sodium carbonate solution. Gallein also reacts according to
the tautomeric form (lactoid formula) :

as it gives a colorless tetracetate, tetrabenzoate, and tetra-
phenylsulphonate. It also gives colorless tetramethyl and
tetraethyl ethers. One particularly interesting derivative is
the colorless trimethyl ether, which resembles phenolphtha-
lein very closely. It dissolves in sodium carbonate or sodium

430 Omdorff and Brewer.

hydroxide solution with a red color, and is precipitated out
colorless by acids. With acetic anhydride it gives very read-
ily a ^^/(7r/^j^ acetate (trimethyl gallein acetate), insoluble in
alkalies. This same colorless trimethyl ether results from
the saponification of the colored tetramethyl ether.

The constitution of gallin was proved by the fact that it
gives a colorless tetracetate and pentamethyl ether. The
gallin tetracetate has acid properties, as was shown by making
a silver salt. The pentamethylether of gallin lias no acid
properties and is easily saponified.

We next took up the question of the constitution of coeru-
lein and coerulin and found that they are best represented by
the following structural formulas :

OH O OH

'\/\oH

^1 Ico

/\/
I I
\/

Coerulein. Coerulin.

This was proved by showing that coerulein gives a triace-
tate, easily reduced in acetic acid solution with zinc dust, and
coerulin, a pentacetate.

Buchka's statement that coerulin gives a tetracetate is in-
correct. Coerulein thus appears as a derivative of anthra-
gallol,

CO OH

OH

which, like coerulein, is soluble in alkalies with a green color.
This will explain why coerulein resembles alizarin and an-
thragallol in its property of forming insoluble lakes with
chromium, iron, and aluminium mordants. The name, aliz-
arin green, by which coerulein is known, recalls this fact,
which has been long known to the dyer. The above formula

Permanganic Acid by Electrolysis. 431

for coerulein also serves to recall the aurin group of dyestuffs
to which it shows certain resemblances.

Full analytical data supporting the views expressed in this
paper will be presented later.

Cornell University, Ithaca, N. Y.,
March, 1900.

PERMANGANIC ACID BY ELECTROIvYSIS.

By h. N. Morse and j. c. Olsen.

In all of the work which has been done in this laboratory
on the reduction of permanganic acid by manganese peroxide,
the oxide has been prepared by partially reducing an acidified
solution of potassium permanganate. But it is well known
that the oxide, when precipitated in this manner, always con-
tains a considerable quantity of potassium, and that it is not
practicable to obtain an oxide free from alkali by increasing
the excess of the acid which is added to the permanganate
solution. The action of the oxide thus formed upon the un-
reduced permanganic acid, which has been the subject of our
study, is doubtless influenced by the presence of potassium in
the former. For this reason we desired to prepare an aqueous
solution of pure permanganic acid, in order that we might ob-
tain from it an oxide free from alkali or other bases. The
need of such an acid was especially felt when we proposed to
take up a study of the relative effects of equivalent quantities
of sulphuric and nitric acids upon the evolution of oxygen
which is produced b)^ the oxide in solutions of the acid ; for,
if the oxide is made by the partial reduction of an acidified
solution of the potassium salt, as has been our practice up to
the present time, it is impossible to foretell in what propor-
tions the potassium will distribute itself among the three acids;
namely, that which is added, the permanganic acid, and the
precipitated oxide. Nor is the case any clearer when the
oxide is produced in neutral solutions to which an acid is
afterwards added.

Two of the methods which have been employed hitherto
appeared likely to yield a fairly pure acid. The first is by
the decomposition of barium permanganate by sulphuric acid ;

432 Morse and Olsen.

and the second, by the solution of the heptoxide in water.
We decided to adopt the latter, and accordingly prepared a
quantity of the anhydride by mixing potassium permanganate
and concentrated sulphuric acid in vessels cooled by ice and
salt. We soon learned, however, that something more than
a low temperature is essential to safety in handling the prod-
uct ; for a minute quantity of the anhydride — certainly less
than half a drop — which had been separated from the sul-
phuric acid, exploded with great violence and with disastrous
consequences to one of us. We were unable to determine
with certainty the cause of the explosion, but suppose it to
have been occasioned either by accidental contact of the an-
hydride with some oxidizable matter or by slight friction be-
tween glass surfaces. Some idea of the force of the explosion
maj' be gained from the fact that one of the flying fragments
of glass passed entirely through a burette which was mounted
in the vicinity, leaving holes over half the diameter of the
burette, the edges of which were entirely free from cracks.
After this experience, we decided to abandon the anhydride
as a source of the acid, and to work out, if practicable, an
electrolytic method of separating it from its salts. If a solu-
tion of a permanganate is electrolyzed in the usual manner,
the acid is quickly reduced by the hydrogen which appears
at the negative pole. This fact suggested the idea of placing
the negative electrode in a porous cup filled with water, and
of drawing off the accumulating alkali from time to time by
means of a siphon. We pass over our earlier arrangements
and preliminary experiments, and give at once the method
which has already yielded us several kilograms of the acid in
pure condition, and which appears to be adapted to its
preparation in any desired quantity, whether for use in the
free condition or for the manufacture of its salts.

The accompanying figure represents the apparatus which
we employ : a, a is a galvanized iron tank through which hy-
drant water flows in order to prevent undue rise of tempera-
ture. We have in use two such tanks, each accommodating
5 cells. (^,(5 is a beaker holding i8oo cc, in which are placed
the permanganate solution, the positive electrode e\ and the
porous cup c. The cup has a capacity of about 250 cc. and

Permanganic Acid by Electrolysis.

433

434 Morse and Olsen.

rests upon the glass tripod d. It contains the negative elec-
trode e, and one end of the siphon j. The open end of the
siphon in the cup is on a level with the upper edge of the
electrode. The electrodes are each 50 mm. square and are
bent to conform to the sides of the cup ; e is of silver and <?' of
platinum. ^ is a large watch-glass with a hole in the center
equal to the outside diameter of the cup. It serves to collect
and return the spray from the permanganate solution and to
protect the latter from the dust in the air. n is a square
wooden strip w^hich is clamped to the edge of the tank. Into
this are screwed the binding posts /, /' , etc. The arrange-
ment b}^ means of which the electrodes are made adjustable
in all directions is more clearly shown in the supplementary
figure, k is 3l glass tube with stop-cock through which dis-
tilled water is made to flow into the cup at an}^ required rate,
the rate depending, of course, upon the frequency with which
it is desired to dilute the alkali bj' emptying the cup to the
upper edge of the electrode, j and m are siphons connected
in an obvious manner in the tube /. Through this sj^stem the
alkaline solution in the porous cup empties into the bottle 0,
whenever its level rises above the upper bend in m. m emp-
ties each time completely, while / remains always full. The
internal diameters of m and / should be related to each
other about as 2 to 3. If they are equal, w will empty / and
itself before the required amount of liquid has passed out
of the cup, and will not again act until the cup has been re-
filled.

The permanganate solution is made as concentrated as the
temperature of the hydrant water which flows through the
tank will permit. During the winter, the prevailing tempera-
ture of the water in the tanks has been from 10° to 11° ; we
have, therefore, employed solutions containing 40 grams of the
salt in a liter. Owing to the destructive effect of the peroxide
on the acid, the solution of permanganate should be filtered
through asbestos.

Usually 8 or 10 of the cells described were arranged in
series. As the current at our disposal was one of 220 volts, it
was necessary to insert additional resistance. For this pur-
pose, we emplo3'ed 6 iio-volt lamps, which were so installed

Permanganic Acid by Electrolysis. 435

that the current could pass through any number of them in
parallel ; also so that any number could be thrown into series
with any other number. On the average, about 40 per cent
of the current was wasted in the lamps.

During the earlier part of the work, the current was broken
at night and the cup removed from the permanganate solu-
tion. It was soon found, however, that when this was done
the acid left in the walls was reduced in the interval, giving
rise to a deposit of oxide, which greatly increased the resist-
ance of the cup. In the later work, therefore, the current was
uninterrupted from the beginning of an experiment to the end.

The resistance of the individual cells was determined twice
daily ; but, as it was subject to considerable temporarj'- fluctua-
tion— rising to a maximum whenever the cup was emptied by
the siphon, and falling again as the refilling proceeded — the
figures here given are to be regarded as having only a very
general significance. As a rule, the cells were found to have
a low resistance in the beginning, amounting to from 5 to 10
ohms on the first day. On the second day, it would rise to
25 or 30 ohms, only to decline through the third and fourth to
perhaps from loto i4ohms, afterwhich the resistance remained
fairly constant to the end. When the average of all the ob-
servations amounted to less than 13 ohms, the cup was re-
garded as a good one, though in some cases the average was
below 9. The increase of resistance during the second day,
and its subsequent decline to a minimum which was thereafter
fairly well maintained, were characteristic of every experi-
ment ; but we could find no adequate cause for the phenome-
non. Occasionally the resistance of a cell would rise much
above 30 ohms, and would continue thereafter much higher
than that of other cells in series with it. In such cases, the
cups were replaced by others. On breaking them, their walls
were found to contain a deposit of black oxide, which was al-
ways denser immediately between the electrodes than else-
where.

The cup used by us was the ordinary porous battery cup ;
but, thinking that greater porosity might have the effect of
diminishing resistance, and therefore of economizing current,
we had made for us a number of new cups, in some of which

436 Morse and Olsen.

the clay was mixed with sand, in others with ground flint,
and in still others with pulverized charcoal which was after-
wards burned out. All of these were found to be more por-
ous than the battery cups with which they were compared,
but, as regards average resistance, they proved to be no bet-
ter than the latter; while, in respect to yield of acid, the most
porous of them were distinctly inferior. Those made from
claj' mixed with sand were too porous. The alkaline solu-
tion which w^as drawn from them was constantlj- colored in
consequence of the infiltration of permanganate during the
time that the cups were only partly filled. Usually, the
alkali drawn from the other, less porous, cups was colorless.
At times, however, when the refilling of the cups was slow —
after having been partially emptied by the siphons — the inner
exposed walls of even the less porous cups would take on a
pink color from infiltration of permanganate. This was after-
wards reduced, giving rise to a deposit of oxide on the walls
or on the bottoms of the cups.

To test the relative merits of the old and the new cups, cells
containing one of each variety were connected in series and
the electroh'sis conducted in the usual manner. The results
are tabulated below :

Material of

Degree of

Average of

Yield of

cup.

porosity.

resistances.

acid.
Per cent.

I

Clay and sand

2-3

i6.i

83.8

II

11 .1 11

1-9

I3-0

87.9

III

" " charcoal

1-4

12.9

89.4

IV

" flint

1-3

12.8

90.7

V

Batter}' cup

I.O

13.2

91.4

The small 5'ield of acid in cells Nos. I and II is probably to
be ascribed, in a great measure if not altogether, to infiltra-
tion of permanganate. In general, the yield increases as the
porosity diminishes. As stated elsewhere, much uncertainty
attaches to the figures representing resistance. They are
significant onh^ as averages of a considerable number of ob-
serv^ations, any one or two of which would have but little
value when standing alone. Nevertheless, it is safe to con-
clude from the values recorded above that the more porous

Permanganic Acid by Electrolysis. 437

cups are not to be preferred because of their smaller average
resistance. As might be expected, there is a more copious
deposit of oxide in their walls, in consequence of which their
resistance soon becomes equal to, or even greater than, that
of the less porous cups.

It is hardly necessary to add that the battery cups which
were examined and used by us differed greatly among them-
selves in respect to porosity and resistance. Several of them
were rejected because of the high resistance which they ex-
hibited even in the fresh state.

To prepare the cups for a second experiment, they were
immersed for a long time in warm, rather concentrated, hydro-
chloric acid, and then kept for several days under small jets
of hydrant water. This treatment, when thorough, sufficed to
put the cups in nearly as good condition as when new.

A 4 per cent solution of potassium permanganate would
yield a very dilute solution of the acid ; and, in order to ob-
tain a more concentrated one, more of the salt must be added
from time to time as the alkali is drawn into the cup and re-
moved by the siphon. Fortunately for purposes of concentra-
tion, the electrolysis is attended in a very striking manner by
the phenomenon of " electrical endosmose." With a current
varying between i and 1.5 amperes, the water passes out of the
permanganate solution into the cup ; i. e., in the direction of
the current, at the rate of about 500 cc. per day of twenty-four
hours. By replacing the water thus withdrawn from the
beakers by equal volumes of the 4 per cent solution of the
salt, we were able to introduce into each cell an additional 20
grams of the permanganate per day ; and, accordingly, to in-
crease the concentration of the acid to any required extent.
We have not yet ascertained how far it is practicable or profit-
able to concentrate the acid in this manner. Up to the pres-
ent time, our strongest acid has not exceeded a ten per cent
solution. But apparently the limit of concentration has not
been reached, since the percentage yield of the acid has not
thus far shown any tendency to decline, as the strength of it
increased.

Though the loss of acid during electrolysis is not relatively
greater when the stronger solutions are made in the manner

438 Morse and Olsen.

described, it appears to be unprofitable to concentrate a weak
acid, free from alkali, by means of the " endosmose" referred
to. In one experiment in which a 3 per cent acid was con-
centrated to one of 7 per cent in this way, 10 per cent of the
entire amount of the acid was lost ; i. e., reduced to oxide.

After discontinuing the addition of permanganate to replace
the water drawn inte the cup, two or three days are required
to remove the remainder of the potassium. During this time
the alkali enters the cup in constantly diminishing quantity
and the endosmose becomes less and less marked. It is not
necessary, however, to continue the electrolysis until no more
alkali can be extracted, for a small quantity of it appears to
enter the cup long after the solution without is free from
potassium. This alkali is derived from the walls of the cup,
where it is probably in combination with the peroxide which
is always deposited to a greater or less extent both upon the
surface and within the walls.

We employ the following expeditious method for determin-
ing at any time the amount of potassium still remaining in the
acid, and, consequently, when to discontinue the electrolysis.
A dilute filtered solution of potassium permanganate, and a
dilute solution of oxalic acid which is free from any base, are
made. It is not necessary to know the strength of either.
Two equal portions of the oxalic acid are measured off and
treated with equal volumes of very dilute sulphuric acid. One
portion is then titrated with the solution of permanganate and
the other with the filtered solution of acid which is to be
tested for potassium. A drop of a neutral solution of hydro-
gen peroxide is added to each solution to destroy the faint
rose color, and the excess of acid in both is determined by means
of an alkali whose relation to the sulphuric acid is known.
Or, the volumes of the permanganate and of permanganic
acid which have been found equivalent, by titration against
equal volumes of oxalic acid, are measured off, treated with
equal volumes of the sulphuric acid, carefully reduced by a
neutral solution of hydrogen peroxide, and the excess of the
sulphuric acid determined as before. If the permanganic acid
is free from potassium, it will, of course, on reduction, neu-
tralize just two-thirds as much of the sulphuric acid as the

Permanganic Acid by Electrolysis. 439

equivalent quantity of permanganate, and any additional
amount which is found to have been neutralized is equivalent
to the potassium still in the permanganic acid. The electroly-
sis has also been followed by titrating from time to time the
alkali delivered by the siphons ; but it is not practicable to
determine, in this way, when the liquid outside of the cup is
free from potassium because it is not known how much of the
acid has been reduced to oxide, or how much alkali the oxide
has carried down with it. In general, however, the deficit of
the extracted alkali has been found to be approximately
equivalent to the loss of acid.

The yield of acid has usually been from 87 to 92 per cent of
the theoretically possible amount. In two cases it reached
94 per cent. The loss is due to various causes, some of which
will doubtless be partially remedied after further and closer
study of the conditions which control them. The greatest
source of loss is the reduction of the acid to oxide, which
takes place within and upon the walls of the porous cups, and
also inside of them. Of the two, the former is the more
serious because of its effect on the resistance of the cups.
Very little oxide is found on the bottoms of the beakers when
care has been taken to protect the solutions from the dust of
the air. Some of the acid spatters upon the covering glasses
and works its way by capillary action to the upper side, where
it is reduced to oxide in contact with the air, or by the oxide
previously deposited upon the glass. Another source of loss
is the retention of the acid by the walls of the cups when they
are removed at the close of an experiment. In two instances
this was extracted and determined, and found to amount to
about 3 per cent of the acid left in the beakers.

When permanganic acid is made in the manner here de-
scribed, several days must elapse before a moderately concen-
trated solution (9 or 10 per cent) can be obtained. The last
of the alkali is extracted very slowly and with a large expen-
diture of current. These considerations led us to try the
plan of placing both electrodes in porous cups. It was fore-
seen that such an arrangement would give us a fairly concen-
trated acid within a short time, and one which would proba-
bly be free from potassium ; but it appeared to be doubtful

440 Morse and Olseyi.

whether the change would prove economical, inasmuch as the
introduction of a second cup would increase the resistance of
the cell. We have tried only one cell of this kind, but so far
as we can judge from the results with it, the introduction of
the second cup is advantageous. Both cups were filled with
water and allowed to stand until the walls were thoroughly-
saturated. They were then placed in the 4 per cent solution
of permanganate and the electrodes introduced. The endos-
mose affected only the cup containing the negative pole. Into
this the water was forced at about the same rate as when one
cup was used, while the level of the liquid in the acid cup re-
mained very nearly constant. The water which passed from
the outer vessel into the alkali cup was replaced, as usual,
with fresh portions of the 4 per cent permanganate solution.
At the end of each twenty-four-hour period, the liquid in the
acid cup was withdrawn and titrated for permanganic acid
and potassium, and the cup was refilled with water. This
was continued for three days. The acid was found to be free
from potassium and to contain no suspended oxide. The
walls of the cup from which it was taken were also free from
any deposit of oxide. The volume of the liquid withdrawn
at the end of each day, its concentration, the weight of the
acid, and also the average current are given below :

Weight

Average

Volume.

HMn04.

Concentration.

current.

cc.

Grams.

Per cent.

Amperes.

ist day 235

14.280

5-95

1.44

2nd " 228

13.068

5-73

I.I5

3rd " 230

16.491

7.17

1-73

yield per ampere-hour was :

Gram.

I St day

0-397

2nd "

0.473

3rd "

0.397

Three days

0.422

The average resistance of the cell for the three days was 14
ohms. At the close of the experiment, the free acid remain-
ing in the liquid outside of the cups was approximately deter-
mined and found to be nearly equal to that which had entered
the cup.

Permanganic Acid by Electrolysis. 441

For purposes of comparison, we give the yield of acid per
ampere-hour and the average resistance in several other ex-
periments in which only one cup was employed :

id per ampere hour.

Average of resistance,

Gram.

Ohms.

0.332

9.6

0-335

10.5

0.340

9-9

0-253

10.7

0.266

lO.O

0.271

9-7

A similar experiment was made on the electrolysis of a 5
per cent potassium dichromate solution in a cell with two po-
rous cups. It was not, however, carried ver}^ far, and we have
at hand only the data which were recorded during the first
two days. For this time, with an average resistance of 18
ohms and an average current of 1.3 amperes, the yield was
0.551 gram of chromic acid per ampere hour. The concentra-
tion of the acid when the portions withdrawn at the end of each
twenty-four hour period were mixed w^as 8.59 per cent. The
absence of any considerable quantity of potassium was roughly
demonstrated by evaporating a measured volume of the solu-
tion to dryness and heating the residue to constant weight at
150°. The weight of the residue differed only about i mg.
from that calculated for the trioxide, CrOj, which had been
found by titration in an equal volume of the aqueous acid.

Our w^ork up to the present time is to be regarded as pre-
liminary only. Much remains to be done in order to ascer-
tain the most economical conditions of the electrolysis — how
far it is profitable to concentrate the alkali around the nega-
tive, and the acid around the positive pole, the effect of tem-
perature on the decomposition of the acid, etc. Enough has
been accomplished, however, to show that the electrolytic
method is a practicable one for the preparation of permanganic
acid in the laboratory. Potassium permanganate is the only
salt of the acid which has hitherto been available in sufficient
quantities for ordinary use in the laboratory ; and this, owing
to its very moderate solubility, fails often to accomplish all
that could be desired of it as an oxidizing agent ; and its use
involves the introduction of potassium, from which it is fre-

442 Morse arid 01 sen.

quently difficult to separate the products of the oxidation.
Many of the other permanganates, however, like those of
strontium, calcium, magnesium, zinc, and cadmium, are ex-
tremely soluble in water, and in their concentrated solutions
they are violent oxidizing agents. It is to be hoped that by
suitable dilution of these, any desired degree of efficiency may
be secured. At i8°, the strontium salt is soluble in one-third
its weight of water, giving a concentration of active oxygen in
solution which has probably not been available up to the pres-
ent time. The permanganates of calcium and magnesium
appear to be still more soluble than that of strontium. Even
the very dilute solutions of the acid act readily upon the car-
bonates and oxides of the metals, so that there is no difficulty
in the preparation of solutions of the salts. Many of these,
though not all of them, can be concentrated on the water-bath
to the crystallizing-point without serious loss, provided the
solutions are freed from oxide in the beginning by filtration,
and are protected during evaporation from dust or other sub-
stances which can start the formation of oxide.

We are now engaged in an attempt to ascertain whether it
may not be generally practicable to determine carbon in or-
ganic compounds by burning them in more or less concentra-
ted solutions of the very soluble permanganates, and, per-
haps, by use of moderate quantities of sulphuric acid, to com-
bine the determination of nitrogen with that of carbon.

The Conductivity of Permanganic Acid.

The conductivity of permanganic acid has been determined
by E. Franke' and J. M. Loven.^ The latter prepared his
acid — which he states was free from sulphuric acid — by dis-
solving the anhydride in water ; while that used by the former
was apparently made by decomposing the barium salt with
sulphuric acid. The results of the two observers appeared to
differ to an extent which justified a redetermination with acid
made by electrolysis. For the preparation of this we decided
to electrolyze the silver, rather than the potassium, salt; be-
cause it is somewhat easier to detect a trace of silver than of
potassium, and because we had observed that the acid derived

1 Ztschr. phys. Chem., i6, 476.
« Ibid.. i7, 374-

Permanganic Acid by Electrolysis. 443

from the potassium salt, when reduced and evaporated, gave
in the flame a slight reaction for the metal, even when the
titration showed it to be free from alkali.

In order to avoid a possible contamination of the acid
through contact with glass, we substituted a large platinum
dish for the beaker which was used in other experiments,
making this the anode. Silver permanganate is soluble in
183 parts of water at 0°, in 107.5 at 15°, and in 59.2 at 28°. 5 ;
hence our saturated solution contained but little of the salt,
and the concentration of the acid proceeded very slowly, not-
withstanding the fact that the electrical endosmose is much
stronger in a case of a saturated solution of silver perman-
ganate than in that of a saturated solution of the potassium
salt. The water entered the porous cup at the rate of about
50 cc. per hour, and at the end of thirty-four hours we had
4.51 1 grams of the acid entirely free from silver. The volume
of the solution was 585 cc. This was filtered through asbes-
tos and used in the determination of conductivity. The
measurements were made at 25°. The concentration of the
acid was determined with great care by means of pure potas-
sium tetroxalate and with calibrated apparatus ; the cells
were standardized with a specimen of potassium chloride
which had been repeatedly crystallized and frequently used
for the same purpose ; and, in general, every reasonable pre-
caution was taken to insure the correctness of the results.
These, it will be seen by the table given below, agree very
much more closely with the results of Loven than with those
of Franke :

M. and O.

Lov6n.

Franke.

V.

t^v.

}^v.

^v.

2

....

315

4

....

332

8

348

16

352.3

354

32

361.2

361

64

371-6

368

345-2

128

375-0

373

346.6

256

374-7

378

346.1

512

376.6

378

343-9

1024

377-3

376

342.8

ON CHLORINE HEPTOXIDE.

By Arthur Michael and Wallace T. Conn.

The marked increase in stability shown by uon-metalHc
oxides and acids with increment of oxygen led us to reinves-
tigate perchloric acid, with a view of preparing its anhydride.
For this purpose a pure acid is necessary, and ?s the product
prepared according to the directions given by Roscoe' is some-
what impure, and can be obtained in this way only with a
great loss of material, we modified the method by heating the
perchlorate and sulphuric acid in a vacuum. Portions of 25
grams of salt and 100 grams of sulphuric acid (of about 1.839
specific gravity at 15° C.) were brought into a fractionating flask*
whose low lateral tube is connected with a second flask placed
in a freezing-mixture, and heated under 10-20 mm. pressure
in a paraffin bath. The reaction starts at about 90° C, and
perchloric acid begins to pass over when bubbles are notice-
able. The heating should be gradual to prevent frothing.
In about an hour the bath may be raised to 160°, and it is
kept at that temperature until all the perchlorate is dissolved,
the operation usually taking about two hours. It was found
impossible to decompose all the perchlorate, as the process
becomes reversible towards the end, and 1.5-2 grams of salt
are easily regained from the cooled contents of the flask. The
crude acid contained traces of sulphuric and hydrated per-
chloric acids, which were removed by a subsequent fractiona-
tion of the freshly prepared substance in a vacuum. The
yield was 85-90 per cent of the theory, if allowance was made
for the regained salt.

The acid was usually very slightly colored and differed in
some of its properties from the substance described by Roscoe.
Under 11 mm. pressure its vapor heated a thermometer to
19° C. In a glass-stoppered bottle the colorless oil colored on
standing, even when kept from light, and after three weeks

1 J. Chem. Soc, i6, 82.

2 The neck of the flask was contracted and the air-tube fitted in tightly by means
of asbestos paper, which was covered by a piece of rubber tubing ; a similar joint
was used between this flask and the receiver. Attached to the air-tube was a PjOs
drying-tube, and between the receiver and manometer a calcium soda lime tube.

Chlorine Heptoxide. 445

was quite dark, but this sample did not explode, although it
was kept several months. In contact with paper or wood it
exploded with a slight blue flame, carbonizing but not igniting
the material. In small amounts it could be mixed with well-
cooled absolute alcohol without explosion, apparently with
ester-formation, as was also the case when dry ether was used.
To 5 grams dry benzene, placed in a freezing-mixture, i gram
acid was added and the cooled tube sealed. The acid dis-
solved, forming a green solution, which soon deposited a car-
bonaceous substance, increasing in amount until the green
color disappeared. The tube opened under slight pressure
and no free acid could be detected in the solution. Iodine
dissolved in the well-cooled acid, using the proportion of 0.5
atom to I molecule, to form a dark solution, which, exposed
to bright light, gradually changed into an almost white sub-
stance. The tube opened under slight pressure, and the gas
contained a little chlorine. On heating the substance gave off
iodine, leaving a white body, which, after dissolving in water,
showed tests for iodic acid.'

The most interesting behavior of perchloric acid is towards
phosphorus pentoxide, and to perform this experiment suc-
cessfully it is necessary to adhere strictly to the following di-
rections : In a small, glass-stoppered retort, connected with a
drying-tube filled with phosphorus pentoxide and placed in a
freezing-mixture of ice and salt, 10 grams of phosphorus pent-
oxide are brought and, by means of a long tube which is bent
inward and contracted at the delivering end and has a rubber
ball attached to the other end , not more than 10 drops of perchlo-
ric acid are added, waiting ten minutes before adding a second
portion. It is advisable to allow the acid to drop on the sides
oftheretort, and the temperature of the freezing-mixture should
be kept below — 10" C. The retort, left in the freezing-mix-
ture, is allowed to stand for a day, then connected with a
well-cooled receiver, and slowly warmed in a water-bath to
85° C., when the new oxide passes over. The product ob-

1 In the last number of the Annalen (310, 369), which we have just received,
Vorlander and von Schilling describe a similar method of preparing the acid, al-
though their yield is not as favorable as ours. Their acid also appears to be some-
what more explosive, which may be due to their using a perchlorate not entirely free
from chlorate.

446 Michael and Conn.

tained in this way is practically pure and may be used for the
experiments described below, but the freshly prepared sub-
stance may be redistilled under ordinary pressure without
danger, when it passes over at 82° C. (corr.)- It should be
well borne in mind that, even though the above directions for
preparing the crude oxide are followed, the apparatus may be
virtually pulverized by a violent explosion, and that the per-
sonal precautions necessary for work of this kind must be al-
ways observed.

Chlorine heptoxide is a colorless, very volatile oil, that on
standing a day begins to turn yellow, after two or three days
is greenish-yellow, with the liberation of a greenish gas. In
comparison with the previously known oxides of chlorine it
shows a remarkable stability and, although when brought in
contact with a flame, or by a sharp percussion, it explodes
with great violence, it may be poured on paper, wood, or sim-
ilar organic matter with impunity, the oxide simply volatili-
zing in the air. Brought into a well-cooled tube with some
stick sulphur and the tube corked, no reaction occurred, even
after standing several days ; and what is a more striking evi-
dence of its stability, it may be poured on a cooled piece of
phosphorus and remain for some days without being attacked.
With cold water it sinks to the bottom of the vessel and passes
slowly over into perchloric acid, but in a closed vessel it re-
quires some days' standing before the peculiar odor of the ox-
ide has disappeared. Dry and cooled benzene dissolves the
oxide, and after a short time a reaction ensues. With iodine
a reaction occurs slowly in the dark, more rapidly in the
light, with liberation of chlorine and formation of a white
solid. This substance begins to decompose at 380° C . , forming
iodine and oxygen, and apparently represents the heptoxide of
iodine. Bromine, under similar conditions, is without action.'

Tufts College, Mass.

1 It is proposed to examine the behavior of concentrated solutions of chloric and
bromic acids towards PjOj. The stability of chlorine heptoxide may be explained
on lines similar to those which I (J. prakt. Chem. [2], 60, 32S) have given for carbon
tetrachloride. This subject, which has a very important bearing on chemical affinity
and on valency will be more fully discussed in a later paper. a. m.

Notes. 447

OBITUARY.
Dr. Guii^laume Louis Jacques de Chalmot,

a former contributor to this Journal, died October 9, 1899.
Dr. de Chalmot was born in Holland. He studied chemistry
at the Realschule and afterwards at the Agricultural College
at Wageningen. He then went to Germany and in 1891 he
received the degree of Ph.D. from the University at Gottingen.
He came to America soon thereafter, and took up research
work in the laboratory of the Johns Hopkins University. In
a few months he accepted a position as assistant chemist in
the Agricultural Department of the State of Virginia at Rich-
mond. In 1895 he became chemist of the Willson Aluminum
Co. and took up the problem of calcium carbide and acety-
lene. His work was markedly successful both in the techni-
cal and purely scientific directions. At the time of his death
he was general manager of the Willson Company. i. r.

NOTES.

Gadolinium.

In the Zeitschrift fiir anorganische Chemie, Vol. 22, Num-
ber 5, C. Benedicks presents a contribution to the knowledge
of gadolinium. The author gives a brief historical sketch of
this element with some remarks in regard to the doubts that
have been expressed as to its elementary nature.

The oxide of gadolinium was first isolated from samarskite
in 1880 by Marignac, who designated it temporarily by the
letters yoc. It was again obtained in pure condition in 1890
by Lecoq de Boisbaudran, who had previously, with Marig-
nac's consent, named the element gadolinium. It was like-
wise obtained quite pure, in 1892, by Bittendorf during his
researches upon the earths of the cerium and yttrium groups.
In 1896, Demarcay obtained gadolinium nitrate from a mix-
ture of the nitrates of gadolinium and samarium.

Some doubts have been expressed in regard to the right of
gadolinium to be classed among the elements. In 188 1, Dela-
fontaine stated that Marignac 's yot was a mixture of the ox-
ides of terbium and decipium. In 1885, Cleve showed that
this position was untenable.

In 1886, from a study of the phosphorescent spectrum of
gadolinium oxide, Crookes concluded that this so-called ele-
ment must be regarded as consisting of at least three compo-
nents. A similar statement, however, was made in regard to

448 Notes.

yttrium, but this conclusion was proved later by Lecoq de
Boisbaudran to be erroneous, he having shown that pure
yttrium oxide gives no phosphorescent spectrum , but that such a
spectrum is produced by the presence of a small quantity of
kindred oxides. The author thinks that the same remarks
can be applied to Crookes's conclusion as to gadolinium, since
the manner of purifying the substance is not indicated.

In 1896, Demarcay isolated wha,t he considered to be a new
earth, designating the element -2", and believing it to be one
of the constituents of gadolinium. But the author states that
the previous work of Lecoq de Boisbaudran on the spectrum
of gadolinium and his own atomic weight determinations prove
that the oxide of gadolinium can be obtained free from De-
marcay's -2".

The best method of preparing the oxide is as follows : The
weaker bases are first removed by partial decomposition of the
nitrates. The material is then subjected to fractional crystal-
lization from concentrated nitric acid, thereupon to fractional
precipitation with dilute ammonia, and afterwards to a final
fractional crystallization from concentrated nitric acid. The
nitrate is readily converted into the oxide.

The average of six atomic weight determinations, made by
converting a weighed quantity of the oxide into the sulphate,
gives for gadolinium the value 156.38. Bettendorf, who has
also determined the atomic weight from very pure material,
has formed for it the number 156.33.

By means of a Salet tube in connection with an induction
coil with a long spiral wire, a beautiful spectrum consisting
of bands and bright lines can be obtained without difi&culty.

The salts are easily prepared from the oxide, which has the
composition Gd,0,, manjy of them crystallizing in forms so
large and perfect as to admit of exact measurement. The fol-
lowing is a list of those prepared by the author :

Gadolinium chloride, GdCl,+ 6H,0.

Gadolinium bromide, GdBr, -|- 6H2O.

Gadolinium platinic chloride, GdCl,.PtCl, -f ioH,0.

Gadolinium aurichloride, GdCl^.AuCl, -f ioH,0.

Gadolinium platinocyanide, 2Gd(CN),.3Pt(CN), + i8H,0.

Gadolinium nitrate, GdCNO,), -f 6iH,0.

Gadolinium nitrate, GdCNO,), -|- 5H,0.

Gadolinium sulphate, Gd,(SO,), + 8H,0.

Gadolinium potassium sulphate, Gd,(S0j3.K,S0^ + 2H,0.

Gadolinium selenate, Gd3(SeOJ3-|- ioH,0.

Gadolinium selenate, Gd,(SeOJ, -f 8H,0.

Gadolinium potassium selenate, Gd,(SeO,),.3K,S04-|- 4H,0.

Acid gadolinium selenite, Gd,(Se03)3.H,SeO, -f 6H,0.

Notes. 449

Gadolinmm ethylsulphate, GdCC^.H^SOJ, + 9H„0.
Gadolinium vanadate, Gd,03.3\VO, + 26HjO.
Basic gadolinium carbonate. Gd.OH.CO3 -(- H^O.
Neutral gadolinium carbonate, Gd(C03)3 -|- i3HjO(?).
Gadolinium oxalate, Gd,(C50j3 + loH^O.
Gadolinium acetate. Gd(C,H30j3 + 4H,0.
Gadolinium propionate, Gd(C3H,Oj3 + sH^O.

Special attention is called to the fact that the double cyan-
ide, 2Gd(CN)3.3Pt(CN), -h i8H,0, is isomorphous with the
corresponding double cyanides of yttrium and erbium, while
the sulphate, Gd„(S0/)3, is likewise isomorphous with the cor-
responding yttrium sulphate.

While nothing definite can be said in regard to the position
of gadolinium in the periodic system, the author thinks it
probable that it will find its place in the eighth horizontal
series of Mendeleeff's scheme. w. m. b.

On Inorganic Ferments.

A paper has recently appeared by G. Bredig and R. Miiller
von Berneck' under the surprising title of '* Inorganic Fer-
ments." We have hitherto been accustomed to regard fer-
mentation as peculiar to, and produced only by, organic liv-
ing matter ; but these authors point out ver}' close analogies
between the action of certain inorganic substances and the or-
ganic ferments. There are many reactions effected by organic
ferments, which are also brought about by finely divided
metals, oxides, etc. Take the following as an example, alco-
hol is oxidized to acetic acid by the oxygen of the air, not only
by means of the ferment niycoderma aceii, but also by finely
divided platinum.

To discover any relations which may exist between the ac-
tion of ferments and inorganic substances, it is desirable to
find some reaction which is effected by both classes of sub-
stances. The reaction must then be studied in every possible
manner, when brought about on the one hand by the ferment,
and on the other by the inorganic substance. Such a reac-
tion is the following :

H,0, = H,0 -f O.

This reaction is produced by organic ferments in general,
and also by finely divided metals and oxides. The authors
study this reaction in detail as it takes place in the presence
of finely divided platinum. To prepare the colloidal solu-
tions, so-called, of the metals, the older method of reducing a
salt of the metal is not used, but an electrical method is em-

1 Ztschr. phys. Chem., 31, 125S (Jubelband fiir vau't Hoff).

450 Notes.

ployed. Pseudo solutions, generally called colloidal solutions
of platinum, iridium, palladium, silver and gold can be prepared
by making bars of the metal the poles of a current, immersing
the poles in water, and bringing them sufficiently close to pro-
duce an electric light under the water. The metal is torn off
in a very fine state of division and forms a dark-brown pseudo
solution in the water. A pseudo solution of platinum was
thus prepared in very pure water. When examined under a
high-power microscope the solution appeared perfectly homo-
geneous, which shows the very fine state of di^'^'sion of the
metal. The platinum in the solution could be determined by
boiling with concentrated hydrochloric acid, when it clotted
and settled to the bottom.

The action of the pseudo solution of platinum, above de-
scribed, on hydrogen dioxide was then studied. It was found,
from the velocity of the reaction, that it is of the first order in
neutral or weakly acid solution, which means that it is a
monomolecular reaction. This is analogous to the action of
ferments.

The second point investigated was the amount of the plati-
num solution required to decompose the hj^drogen dioxide.
It is characteristic of the action of ferments that a very small
quantity is capable of bringing about a large amount of de-
composition. It was found that a gram-atomic weight of
platinum in 70,000,000 liters of water accelerates the decom-
position of hydrogen dioxide to an appreciable extent, and can
decompose, relatively, an enormous amount of the dioxide.
Other inorganic substances, such as manganese dioxide and
lead dioxide have the same property.

The action of ferments can be modified by change of con-
ditions such as temperature, presence of foreign substances,
etc. The action of the platinum is affected by change in tem-
perature, by the presence of electrolytes, by the concentration
of the solution, etc.

But the most striking analogy between the action of fer-
ments and that of the platinum is the following : It is well
known that a very small quantity of certain substances is capa-
ble of poisoning the organic ferments and entirely destroying
their activity. The poisonous action of hydrocyanic acid and
other molecules and ions, on organic ferments, have been
studied quantitatively, and the most striking result is the al-
most infinitesimal quantity of the poison required to destroy
the characteristic action of the ferment, and even the ferment
itself.

It is shown by Bredig and von Berneck that the platinum
solution can also be poisoned by minute traces of certain sub-

Reviews. 451

stances, so that it will no longer have the same power to de-
compose hydrogen dioxide. Thus, a gram-molecular weight
of hydrocyanic acid in 1,000,000 liters of water will retard,
quite appreciably, the decomposition of the dioxide by the plati-
num solution. Hydrogen sulphide acts to nearly the same
extent, and mercuric chloride also shows a marked power to
poison the platinum solution.

These are some of the analogies pointed out between the
action of organic ferments and of the finely divided metals and
oxides of the metals. It is too early to draw any final con-
clusion as to how deep-seated these analogies are, but they are
certainly interesting and promise much for the future. Should
it be shown that these relations are fundamental, it will be of
service in studying the action of organic ferments in general,
since the metals and even the metallic oxides are simple sub-
stances in comparison with the organic enzymes. h. c. j.

REVIEWS.

A System of Instruction in Quai^itative Chemicai. Anai,ysis. By
Arthur H. Elliott, Ph.D., Professor Emeritus of Chemistry and
Physics in the College of Pharmacy in the City of New York, and
George A. Ferguson, Ph.B., Professor of Analytical Chemistry and
Director of the Chemical Laboratory in the College of Pharmacy of
the City of New York. Third edition, revised and enlarged. 1899.
Published by the authors. 155 pp.

As the first and second editions of this book have been
favorably noticed in this Journal,' it is only necessary to say
that the revision is judicious, and that the manual will be found
especially useful to those teachers who are compelled to instruct
large classes without assistance, as the notes of analytical de-
tails are unusually full and minute. E. R.

Determination of Radicles in Carbon Compounds. By Dr. H.
Meyer, Docent and Adjunct of the Imperial and Royal German
University, Prague. Authorized translation. By J. BishopTinglE,
Ph.D., F.C.S., Instructor of Chemistry at the Lewis Institute, Chi-
cago, 111. First Edition. First Thousand. New York : John Wiley

. & Sons ; London : Chapman & Hall, Limited. 1899. pp. 133.

Dr. Meyer's book is favorably known to chemists in the
original and its character is such as to lead to the belief that
the English translation will be of service. No doubt some of
the methods described could be made part of a laboratory
course in organic chemistry to the great advantage of the
course, and it is to be hoped that those who have charge of the
work in organic preparations in our larger laboratories will
avail themselves of some of the suggestions made in the book.

There are five chapters : The first treats of the determina-

1 Vol. 15, 373 ; and i6, 476.

452

Additions.

tion of hydroxyl ; the second of the determination of meth-
oxyl, CH3O— , ethoxyl, C,H,0— , and carboxyl, COOH ;
the third of the determination of carbonyl ; the fourth of the
determination of the amino group and of the imino group ;
the fifth of the determination of the diazo group, of the hydraz-
ide group, of the nitro group, of the iodoso and iodoxy
groups, and of the peroxide group.

The following quotation will indicate the object of the book :
" The quantitative analysis of organic compounds, as usually
performed, consists almost exclusively in the determination of
ions, since in the present state of the science this generally
suffices for the identification of the substance ; but to attain
the same end in the case of organic bodies the elementary
analysis requires supplementing by other methods. The per-
centage composition gives no information about the relative
arrangement of the atoms in the molecule, but the demand for
methods of analysis which will yield such knowledge increases
with our growing insight into the constitution of carbon com-
pounds. * * * The successful methods hitherto proposed
for the determination of organic radicles have been collected
together in this work, and it is hoped that they may serve to
indicate the direction in which research may be successfully
prosecuted for the discovery of new ones applicable to hitherto
unforeseen conditions."

The book is recommended to teachers and advanced stu-
dents of chemistry, i. R-

ADDITIONS.

*^Vol. 23, pages 309, 310, and 311.

Under plate on page 309 add :

I. Metadinitrobenzene ; 2. Orthonitrophenol ; 3. Meta-
methoxybenzenesulphonamide ; 4. Benzenesulphonamide ; 5.
Nitromethane ; 6. Paramethoxybenzenesulphonamide ; 7.
Orthomethoxybenzenesulphonamide ; 8. Trinitrotolugn^.

Under plate on page 310 add : o,(?,f i'l.^aM\ j)-'^ ^

I. Potassium Chlori(ie ; 2. Potassium Nitrate ; 3. Ammo-
nium Chloride; 4. Ammonium Nitrate; 5. Silver Iodide;
6. Strontium Nitrate.

Under plate on page 311 add :

I. Sodium Bromide; 2. Potassium Metanitrobenzenesul-
phonate ; 3. Sodium Bromate ; 4. Metanitrobenzenesulphon-
amide ; 5. Benzoic Sulphinide.

Vol,. XXIII. June, 1900. No. 6.

AMERICAN

Chemical Journal

Contributions from the Sheffield Laboratory of Yale University.

LXXIV.— RESEARCHES ON THE SODIUM SAI.TS OF
THE AMIDES.

By Henry L. Wheeler.

The work described in this paper was undertaken with the
object of determining the relative ease with which certain acid
amides yield sodium salts, and of determining whether a
stereochemical interference is noticeable in this series, by com-
paring the velocity at which, under given conditions, meta-
meric amides of the form R— NH— C— H and H— NH— C— R

II II

O O

form salts. Such a comparison, taken in connection with a

similar examination of the disubstituted formamides,

RNHCOR' and R'NHCOR,

in which R=aryl and R' = alphyl, might be expected to
throw new light on the disputed question of the structure of
these salts. For example, which one of the above-mentioned
isomeric forms is most favorable for the formation of sodium
salts, or in other words, in whatposition does R have the more
retarding effect ? And is this effect general for one of these
types? If the sodium attaches itself to nitrogen, then R should
exert a greater interference when attached to the same atom

454 Wheeler.

than when further removed or attached to carbon ; for exam-
ple, formanilide, CeH^NHCOH, should then give a salt less
easily than benzamide, HNH — COC.H,.

As regards the velocity of formation of the salts, the question
of relative acidity or negative character of the molecules arises
at once. Do the amides give salts in accordance with the
strength of the acids from which they are derived ? To what
extent does the basic character of the amino group influence
the velocity of formation of the salts ?' The latter questions
are evidently the first to be decided.

It was necessary at the outset to devise a new method for
the preparation of the sodium salts. It was found that sodium
amalgam answers the purpose better than metallic sodium ;
that in boiling benzene the former does not become covered
with a coating, as the metal does ; and that salts can be pre-
pared by its use which cannot be obtained by any of the pre-
viously existing methods.

In order to determine whether acidity is the chief factor in
determining the velocity of formation of the sodium salts, the
following anilides in molecular proportions, taking 0.5 gram
of acetanilide, were dissolved in 100 cc. of benzene and boiled
for one hour with 9 grams of a 4.7 per cent amalgam. The
solutions were then filtered as rapidly as possible, and the
amount of anilide which had formed sodium salt was deter-
mined as described below. The following figures approxi-
mately show this amount in percentages, the affinity constants
of the respective acids being given for comparison :

Average of
two experiments. K.2

Formanilide, C,H,NHCHO, i.oo Formic acid, 0.0214

Acetanilide, C.H.NHCOCH,, 82 Acetic " 0.0018

Oxanilide, (C,H,NHCO— )„ 63 Oxanilic " 1.21

Benzanilide, C,H,NHCOC,H,, 38 Benzoic " 0.006

From this it is evident that the results do not correspond
with the strengths of the acids. Thus, oxanilide should give

1 It i3 weU known that the presence of negative groups in the amides favors the
formation of salts, dibenzamide, benzoj'lurethane, etc., are soluble in alkali, while
benzamide is insoluble, and again, the acyl cyanamides have stronger acid proper-
ties than the acids from which they are derived. Bader : Ztschr. phys. Chem., 6, 305.

2 Ostwald : Ibid., 3, 241.

Sodium Salts of the Amides. 455

a salt more readily than formanilide and acetanilide, and
benzanilide more readily than acetanilide.

That basicity does not exert the most important influence,
the acyl radical being the same, is shown by the following re-
sults, which were obtained under the same conditions :

Benzamide, H.NCOC.H,, 98

Benzanilide, C,H,HNCOC,H„ 38

Benzoylbenzylamine, C,H,CH,HNCOC,H,, i

K.l

Ammonia, 0.0023

Benzylamine, 0.0024

Thus, if the positive character of the molecules determined
the velocity of formation of the salts, benzanilide should
react more readily than benzamide ; and since benzylamine
has practically the same basicity as ammonia, the benzoyl
compounds should give salts with equal readiness.

It is interesting to note here that Hjelt^ found that the rate
of saponification of the alkyl malonic esters is not in agree-
ment with the affinity constants of the corresponding acids,
but that it agrees, rather, with what would be expected from
the theory of stereochemical interference.

In order to determine which one of the two general forms,
RNHCOH or HNHCOR, is more favorable for salt forma-
tion, the following amides were examined under the same
conditions as described above, except that 23 grams of a 0.73
per cent amalgam were used. The figures represent the per-
centages of amide converted into sodium salt under these con-
ditions :

Average.

Formanilide, C,H,.NHCO.H, 57

Acetanilide, C,H,.NHCO.CH„ 8

Propionanilide, C,H,.NHCO.C,H,, 12

Benzamide, H.NHCO.C.H, 51

Methylbenzamide, CH,.NHCO.C,H„ o

Ethylbenzamide, C,H,.NHCO.CeH,, 0'

In the following cases the conditions were the same as in
the first experiments, using a 4.7 per cent amalgam. In all

1 Bredig : Ztschr. phys. Chem., 13, 306.

2 Ber. d. chem. Ges., 29, 1866.

456 U' heeler.

cases excepting formanilide and benzamide, however, 150 cc.
of benzene were used :

Average.

Formanilide, C,H,NHCOH, 100

Orthoformtoluide, C,H,CH3NHC0H, 96

a-Formnaphthalide, C,„H,.NHCOH, 99
2,4,6-Trimethylformanilide, C,H,(C,H,),NHCOH, 96

Benzamide, HNHCOCeH,, 98

Orthotoluamide, HNHC0C,H,CH3, 91

«r-Naphthamide, HNHCOC,„H., 76

2,4,6-Trimethylbenzamide, HNHCOC.H.CCH,),, 88

These results, thus far, show that a disubstituted formamide
gives a salt less readily than one that is monosubstituted,
which would be expected from the theory of stereochemical
interference; and that when the larger or interfering radical is
attached to nitrogen it has less effect in retarding the forma-
tion of sodium salts than w^hen attached to the keto group.
They, therefore, indicate that the sodium is attached to oxy-
gen." Although it is true that the results all point in this di-
rection, nevertheless the interference w^hich might be expected
in certain cases does not exist, while in others an unexpected
inertness is showm. An examination of the isomeric cyclo-
amides, oxindol (I) and phthalimidine (II), under the same
conditions as in the first experiments, showed that in both
cases the amount of amide which had formed salt was prac-
tically 100 per cent, while benzojdbenzylamine (III), which
has an acyclic structure corresponding to phthalimidine, as
already stated, gave practically no salt under these condi-
tions :

c,h/ >co, c,h/ >NH. >NH.

I. II. III.

The interesting results obtained by Remsen and Reid' on
the saponification of the substituted benzamides show that
substituents in the ortho position "exert a remarkable protec-
tive influence on the amide group." The order in which the
various groups produce a retardation was found to be as fol-

1 Compare Michael : J. prakt. Chem., 60, 322.

2 This Journal, 21, 281.

Sodium Salts of the Amides. 457

lows, in order of decreasing influence : — NO,, — I, — NH,,
— CH„ —CI, —OH, — O.C,H„ — O.CH3. Unfortunately,
for a comparison with the velocity of formation of the corre-
sponding sodium salts, only — NH,, — CH3, and the least in-
terfering groups, — O.CjHg and — O.CH,, are probably avail-
able for examination by the present method. The results
with orthotoluamide indicate, however, that interference
also plays a part in the formation of the sodium salt of that
compound, although it is not shown in a very decided man-
ner. On the other hand, it is curious that benzoylbenzyl-
amine, and methyl- and ethylbenzamides are so inert, and
that they give salts less readily than benzanilide, while the
results with trimethylbenzamide are most unexpectedly high.
The derivatives of 2-4-6-trimethylbenzoic acid, like other
diorthosubstituted acids, are notably inactive in reactions
which are supposed to involve an addition to theketo group.'
The acid is not converted into its ester by means of hydrogen
chloride and alcohol.^ The ester' and amide^ are difficult to
saponify, while the chloride is remarkably stable towards
water and alkalies. Diorthosubstituted acid chlorides in
general react readily with ammonia,^ however, and the silver
salt of trimethylbenzoic acid gives almost a quantitative yield
of the ester with methyl iodide.* It is assumed that these lat-
ter reactions do not involve anj'- addition to the keto group,
but take place by direct substitution.' The fact now that
2,4,6-trimethylbenzamide forms a sodium salt practically as
readily as orthotoluamide, and that no very decided
stereochemical interference is found in this reaction, would
suggest that here, also, direct substitution takes place, and
that the sodium is attached to nitrogen. On the other hand,
if the sodium is attached to oxygen, the reaction must be an

1 Henry : Ber. d. chem. Ges., lo, 2041 ; Wegscheider : Monatshefte, 16, 14S ; An-
geli : Ber. d. chem. Ges., 29, R, 591 ; Peckmann ; Ibid., 31, 504.

2 V. Meyer : Ibid., 37, 510.

3 Ibid., 27, 1263.

* Sudborough : J. Chem. Soc. (London), 1897, 229.

5 Sudborough : Ibid., 1S97, 234.

6 Meyer : Ber. d. chem. Ges., 37, 1580.

7 Max Scholtz : Der IJinfluss d. Raumerfiillung d. Atomgruppen ; Sudborough:
Loc. cit.

458 Wheeler.

addition of sodium hydrate to the keto group, and then a
separation of water, as follows :'

CH, CH,

I I

CH— ( \— CO.NH, CH— < )— C— OH

\

ONa

CH, CH,

CH,

_r^^^

^^-\ /^\

ONa

CH,

If this is true, it follows that 2,4,6-trimethylbenzamide, out
of all harmony with the theory of stereochemical interference,
must readily form an addition-product with the alkali. This
is precisely what takes place, not only in this case but also
with the symmetrical 2,4,6-tribrombenzamide, which Sudbor-
ough states exhibits the greatest amount of stereochemical in-
terference, as regards its hydrolysis, of any of the amides ex-
amined by him.

The ease with which 2,4,6-trimethylbenzamide forms a
sodium salt is therefore in harmony with the theory that the
metal in the sodium salts of the amides is attached to oxygen.

I have found that 2,4,6-trimethyl- and tribrombenzamides
are readily removed from even their dilute solutions in ether
by simply shaking with powdered potassium hydrate, the ad-
dition-product being absolutely insoluble in ether. On filter-
ing and treating the residue with water, these compounds un-
dergo dissociation and the unaltered amides are recovered.

In order to prepare the compound C.H^BrjCONH^.NaOH,
it is simply necessary to pour an excess of the amide dissolved
in benzene over finely powdered sodium hydrate, whereupon

1 Naturally a mere trace of moisture would be sufficient, since the water which
separates would again react until all the amide is converted by the sodium into salt.

Sodium Salts of the Amides. 459

the latter is quantitatively converted into the addition-prod-
uct.'

This is all the more surprising since Pechmann* found that
2,4,6-trimethylbenzoic ester does not form an addition-product
with sodium alcoholate, which is one of the notable properties
of ethyl benzoate, and I have found that 2,4,6-tribrombenzoyl
chloride and methyl 2,4,6-tribrombenzoate do not give addi-
tion-products with potassium hydrate, and also that 2,4,6-tri-
brom-N-dimethylbenzamide yields no sodium hydrate com-
pound under the same conditions that proved successful with
the amide.

The readiness with which the diorthosubstituted amides
form addition-products with the alkali, contrasted with their
inertness as regards saponification, suggests that the processes
involved in the formation of sodium salts and in saponification
are not analogous. If we accept the addition theory of saponi-
fication the existence of these alkali addition-products shows
that the stereochemical interference in regard to the saponifi-
cation of these amides, at least with alkali, is not due to a
protection from attack, but, for some other specific reason,
they give up ammonia with difficulty.

That these alkali addition-products have the elements of the
alkali attached to the keto group, and are not merely so-called
molecular compounds, is shown by the behavior of the sodium
hydrate addition-product of thioacetanilide with benzoyl chlo-
ride, which reaction yields acetanilide and thiobenzoic acid,
as follows :

^NHC.H, yNHC.H, CH3CONHC.H,

CH,C— OH — CH3C— OH — +

^SNa ^SCOC.H, HSCOC.H,

That they have the formula

yNH, .NHNa

RC— OH and not RC— OH

^ONa ^OH

1 Interesting also, in this connection, is the fact that KUster and Stallberg (Ann.
Chem. (Liebig), 378, 217) state that 3-nitro-2,4,6-trimethylbenzamide dissolves in
aqueous alkali and even in carbonates.

2 Loc. cit.

460 Wheeler.

is shown by the behavior' of the addition-products of formani-
lide, formtoluide, etc.

When heated, or, as found by Tobias," when simply al-
lowed to stand over sulphuric acid, these compounds decom-
pose as follows :

HC— O'H — * +

^ONa HCUONa

This formula, as representing the structure of these addi-
tion-products is objected to by Cohen and Brittain,' since
when heated the analogous sodium alcoholate addition-prod-
ucts^ lose alcohol and yield sodium' acetanilide, which, with
methyl iodide, gives methylacetanilide, methylaniline, etc.
Their statement that this formula "would necessitate a molec-
ular change of a very complex character which is scarcely
justified b}^ the facts" no longer holds true, since phenyl-
formimidomethyl ester undergoes this rearrangement with
methyl iodide, even in the cold, yielding methylacetanilide :

/CH3
\OCH3 ^O

EXPERIMENTAL PART.

Experiments with a o.'j^ Per Cent Amalgam.

Formanilide . — The method adopted in general for the deter-
mination of the ease with which the amides form salts was as fol-
lows : 0.4481 of a gram of formanilide and the equivalent of the
other amides were dissolved in 100 cc. of benzene and heated,
whereupon 23 grams of a 0.73 per cent amalgam were added.
This is somewhat more than twice the calculated quantity of
sodium. After boiling one hour, the solution was filtered
and the residue of sodium salt was collected on the filter,
while the heavier amalgam was allowed to remain in the flask.

1 See also Hantzsch: Ann. Chem. (Liebig), 296, 91.

2 Ber. d. chem. Ges., 15, 2451.

8 J. Chem. Soc. (London), 1898. 162.

4 Cohen and Archdeacon : Ibid., 69, 91.

5 Seifert : Ber. d. chem. Ges., 18, 1358.

Sodium Salts of the Amides. 461

The whole was washed with somewhat over 50 cc. of warm
benzene by means of a wash-bottle and the filtrate evaporated
in a weighed flask, the residue being dried in a stream of air
at ordinary temperature. In most cases the residue consisted
of unaltered amide, which gave directly the weight of ma-
terial not forming sodium salt. In all cases this residue, after
weighing, was treated with water and titrated with a standard
hydrochloric acid solution, using an aqueous solution of the
sodium salt of orthonitrophenol as indicator, which recom-
mended itself, since it gives a very sharp end-reaction by gas-
light and carbonic acid does not interfere except in the cold.

In this manner the amount of sodium salt dissolved by the
benzene was determined and the correction made. The
amount of amide forming sodium salt was then determined by
difference. In some of the experiments the amount of anilide
recovered, after boiling with amalgam, was determined by
saponifying the anilide with strong hj^drochloric acid and then
determining the amount of aniline volumetrically by means of
a standardized solution of potassium bromate and bromide.'

Two experiments with formanilide, performed as above,
gave 0.1963 and 0.1859 gram anilide not attacked, corre-
sponding to 56 and 58 per cent as sodium salt. This sodium
salt is insoluble in benzene.

It must be understood that the quantitative results given in
this paper are merely approximate, and in certain cases it is
difficult to get closely agreeing results. The first difficulty
encountered is the fact that with the solid amalgam it is diffi-
cult to get the same state of division each time, although in
each case the amalgam was freshly powdered and passed
through a moderately fine sieve before it was used. A curious
result was observed when two different preparations of a semi-
solid amalgam was used, both containing the same percentage
of sodium as far as could be determined; i. e. 0.72 and 0.73
per cent. By means of the latter, when acetanilide was boiled
for one hour, 8.7 and 8.0 per cent was found to have been
converted into sodium salt; with the former preparation, how-
ever, on boiling for two hours three experiments each gave

1 Reinhardt : Ztschr. anal. Chem., 33,90; Compare Francois and Deniges : J.
Sec. Chem. Ind., 28, 866.

462 Wheeler.

3.9 per cent as the amount of anilide that had been attacked.

It has previously been observed that certain preparations of
sodium amalgam have given widely different results in reduc-
tion experiments' and Aschan "explains this by the assumption
that impurities cause the evolution of h5'drogen in the molec-
ular form and not in an active state. This explanation fails in
the above case. With these results, which fortunately oc-
curred at the beginning of the work, all the comparisons were
afterwards made with portions of the same preparations.

Other sources of error are as follows : The sodium salts are
bulky, gelatinous, and diflScult to wash when prepared in this
way ; therefore, the small quantities of amides used in the ex-
periments, and, in some cases, the residues left on evaporating
the benzene, are difficult to dry. In no case was any reduc-
tion of the amide observed, as is the case when the amides are
acted on with amalgam in acid^ or alkaline'' solutions.

Acetanilide . — When two experiments with 0.5 gram of this
anilide were performed as described above, 8.7 and 7.9 per
cent of the anilide was found to have been converted into
sodium salt. This quantity was all dissolved in the benzene
solution. Experiments at 20°, the other conditions being ex-
actly the same, gave peculiar results. It was found that 17.8
and 20.8 per cent of the acetanilide had been converted into
sodium compound, or about two and one-half times as much
as at the temperature of boiling benzene. The explanation
of this was found on filtering the benzene solution, when be-
fore the washing was complete the sodium hydrate addition-
product mentioned by Cohen and Brittain* began to separate.
This owed its formation to the unavoidable presence of mois-
ture absorbed by the amalgam and benzene during the
manipulation. These authors state that the alkali addition-
products are readily dissociated at the temperature of boiling
ether ; therefore, all other experiments described here
were performed at the temperature of boiling benzene.

The sodium hydrate addition-product of acetanilide is sol-

1 Lassar-Cohn : Lab. Manual Org. Chem., p. 308.

2 Ber. d. chem. Ges., 24, 1866.
8 Guareschi : Ibid., 7, 1462.

* Hutchinson : Ibid., 24, 173.
5 Loc. cit.

Sodium Salts of the Amides. 463

uble in benzene, while that of formanilide is insoluble ; there-
fore, at temperatures at which the intermediate addition-prod-
ucts are stable, more sodium compound should be formed in
the case of acetanilide than with formanilide, when treated
with metallic sodium covered with a layer of sodium hydrate.
The results of the following experiments proved this to be
true. The anilides were dissolved in 100 cc. of benzene
(0.4481 gram formanilide and 0.5 gram acetanilide) and shaken
in a machine for one hour, with 0.5 gram of sodium, weighed in
the air whereupon formanilide gave 5.3 and 5.9 per cent, and
acetanilide 20.5 and 26.3 per cent anilide as sodium compound.

Propionanilide. — One experiment w'ith 0.5518 gram of this
anilide, which was performed in boiling benzene, gave no tur-
bidity or separation of salt from the benzene solution, but on
filtering and evaporating, 12.2 per cent was found to have been
converted into salt.

Benzamide.— In this case two experiments with 0.4481 gram
of material gave 1.4 per cent of amide as sodium compound
dissolved in benzene and 49.1 and 50.2 undissolved; total
50.5 and 51.6,

Methyl- and Ethylbenzamides gave no evidence of any salt
formation under the above conditions. The benzene solution
was found to be free from alkali and, on evaporating off the
benzene, the weights of the residues came from 2 to 5 per cent
too high, it being difficult to dry the material without loss.

Experiments with a ^.y Per Cent Amalgam.

Formanilide. — In each of the following experiments 9 grams,
or five times the calculated quantity of amalgam, was used.
0.4481 gram of this anilide, when treated as above, gave no
residue on evaporating the benzene; hence the amount of salt
formed was 100 per cent.

Acetanilide. — One-half gram gave, in two experiments, 29.6
percent as salt dissolved in the benzene, and 48.1 percent
undissolved in one; and 29.6 and 56.8 per cent in another ;
total 77.7 and 86.4 ; average 82. L,ack of better agreement is
due to the difficulty of drying, owing to the amount of salt
dissolved by the benzene.

464 Wheeler.

Oxanilide. — In two experiments 0.4444 gram gave 65.4 and
60.0 as monosodium salt. This salt is insoluble in benzene ;
it was separated from all but traces of the amalgam by decan-
tation, and a sodium determination gave ;

Calculated for
CeHjNHCGCGNaNCeHs. Found.

Na 8.8 9.1

Water decomposes the salt,' liberating anilide.
Benzanilide. — Attempts to prepare a sodium ^,alt for syn-
thetical purposes by boiling this anilide in benzene with
sodium were unsuccessful. Quantitative experiments indica-
ted that over 95 per cent of the anilide was unaltered. The
use of xylene, as recommended by Hepp,* gave no better re-
sult. The method of Seifert^ and Blacher^ for the preparation
of sodium salts also failed in this case. It was prepared, how-
ever, by boiling the concentrated benzene solution with .an 8
per cent amalgam. Ten grams anilide gave about 7 grams of
salt after boiling several hours. It was separated from the
excess of amalgam by decantation. As the amalgam used
was not freshly prepared and contained some sodium hydrate,
the results on analysis came high. The percentage of sodium
calculated is 10.5, found 11. 7. In the experiments of Paal
and Often* on the action of acyl chloride on the sodium salts
of the anilides, they invariably treated the salt of a lower ani-
lide with a chloride of higher acid, benzoyl chloride with
sodium acetanilide, sodium formanilide, etc., and obtained
nothing but the anilide of the higher acid. The action proved
to be abnormal as diacyl anilides were not obtained. It
seemed of interest, therefore, to tr)^ the action of acetyl chlo-
ride on sodium benzanilide under the same conditions as de-
scribed by the above authors, when it was found that the ac-
tion was also abnormal in this case, and that nothing but
benzanilide was obtained.

1 In determining the amount of sodium in the following new salts, which was
done volumetrically, a determination of the amount of mercury was also necessary
in some cases ; in others this was very small and was disregarded. The decanted
precipitates always contain more or less mercury.

2 Ber. d. chem. Ges., lO, 328.
Z Ibid., 18, 1357.

^Ibid., 28,435-
5 Ibid., 23, 25S7.

Sodhifn Salts of the Amides. 465

Quantitative experiments with 0.7296 gram anilide, on the
formation of sodium benzanilide, gave 35.3 as the amount of
amide which had formed salt, in one, and 40.5 per cent in an-
other ; average, 37.9. The salt is insoluble in benzene ; it is
bulky and gelatinous, but when dried forms a white, amor-
phous powder.

Benzamide. — The amide (0.4481 gram) gave 98 per cent as
the amount that had formed salt, while 1.4 per cent of the
amide was in solution as sodium salt. After decanting the
bulky, gelatinous salt and rapidly drying in a steam oven a
sodium determination gave :

Calculated for
C,H,NONa.

Found,

16.0

16.2

Na

Ethylbenzamide. — Two experiments with 0.5518 gram each
of this amide, again with the stronger amalgam, gave no evi-
dence of any salt formation. On boiling the benzene solution
it remained perfectly clear, and on examining the residue left
on evaporating the benzene it was found that less than 0.7 per
cent of the amide had formed salt.

Benzoylbenzylamhie . — This was prepared by the Baumann-
Schotten reaction. Two experiments with 0.7815 gram of
material gave perfectly clear solutions on boiling with the
amalgam, and an examination of the residue, on evaporating
the benzene solution, indicated that in both cases i.o per cent
of the amide had been converted into sodium salt. The re-
covered material melted sharply from 106° to 107°.

Oxindol. — This cycloamide (0.4926 gram) gave a bulky,
gelatinous separation of salt immediately on warming and, on
evaporating the filtered solution, the residue weighed 0.0050
gram. It was found to be free from alkali, and, therefore, 99
per cent of the amide was converted into salt. A sodium de-
termination gave :

Calculated for
CgHgNONa. Found.

Na 14.8 15.3 ^

Phthalimidine. — This amide (0.4926 gram) gave a bulky,
gelatinous salt, like the above, and the recovered residue of

466 Wheeler.

unaltered material weighed 0.0066 gram ; hence 98.7 per cent
of the amide formed salt. A sodium determination gave :

Calculated for
CjHeNONa. Found.

Na 14.8 14.8

Phenyl OX amide. — This amide (0.3037 gram) refused to dis-
solve completely in 100 cc. of benzene before adding the
amalgam, so that the results are not directly comparable with
the above. The amount of amide converted into salt was
found to be 57.3 per cent.

Oxamide zMdi phthalamide are insoluble in benzene. Form-
amide^ immediately liberates ammonia, while acetamide ap-
pears to be less readily decomposed by the above treatment.

The following experiments required the use of 150 cc. of
benzene, owing to the diflSculty with which o'-naphthamide
dissolves in this solvent.

Orthoformtohdde. — This was one of the few cases in which
the amalgam showed any tendency to " cake," or the salt to
attach itself to the amalgam ; nevertheless, 0.5 gram gave
95.7 per cent as the quantity of toluide forming sodium salt ;
3 per cent of this was dissolved by the benzene. The salt
separated by decantation gave :

Calculated for
CgHgNONa. Found.

Na 14.6 14.2

Orthotoluamide . — This was prepared by the method sug-
gested by Remsen and Reid, The amount used was 0.5
gram, and 90.6 per cent of this was found to have formed
sodium salt. No salt was found in the benzene solution, A
sodium determination gave :

Calculated for
CgHgNONa. Found.

Na 14.6 15. 1

a-Formnaphihalide . — Of this, 0.6333 gram gave 98.9 per cent
as sodium salt. It is bulky and gelatinous, and therefore fil-
ters slowly. Less than i per cent of salt was found in the
benzene. A sodium determination gave :

1 That this amide gives a sodium salt with great ease, by a less energetic reac-
tion, is shown by the method used by Freer and Sherman (This Journal, i8, 580).

Sodium Salts of the Amides. 467

Calculated for
CiiHgNONa. Found.

Na II. 8 12.2

a-Naphthamide. — The nitrile was prepared from ar-naph-
thylamine hy the Sandmeyer reaction. Of the amine 85.8
grams gave 13 grams of nitrile boiling at about 300°. When
this was dissolved in an excess of alcoholic sodium hydrate
and warmed for a few minutes, the first separation of crystals
weighed 5 grams and were practically pure amide, melting at
202°.

The amide (0.6333 gram) gave 23.6 percent unaltered ma-
terial. After being heated as above, this melted sharply at
202°. The amount of amide as sodium salt was therefore 76.4
per cent. A sodium determination gave :

Calculated for
CjiHgNONa. Found.

Na II. 8 12.4

2,^,6-Trim,ethylform.anilide. — The mesidine was prepared by
heating trimethylphenylammonium iodide at 210° with a few
drops of methyl alcohol. It is more readily obtained from
mesitylene by nitration and reduction. The formyl compound
melted at 177°. Of this, 0.6037 gram gave 95.9 per cent as
sodium salt, which separated as a bulky, gelatinous mass.
Less than i per cent of this was dissolved by the benzene. A
sodium determination gave :

Calculated for

CioHijNONa. Found.

Na 12.4 12.3

2^4,6-Trimethylbenzamide. — For the preparation of this
amide mesitylene was nitrated according to the method of
Schulz.' After distilling in steam, the oil obtained was dis-
tilled at 15-20 mm. pressure, when the fraction, i20°-i30°,
was collected. It boils for the most part at i5o''-i54° at about
50 mm. pressure. 131 grams of mesitylene gave 61 grams of
crude nitro-compound. This, on reduction, gave 25.3 grams
of mesidine boiling from 224°-226° (uncorr.). From this the
nitrile was prepared according to Sandmeyer's reaction, using
the conditions of Liebermann and Birukoff^ for the prepara-

1 Ber. d. chem. Ges., 17, 477.

2 Ann. Chem. (Liebig), 240, 286.

468 Wheeler.

tion of the corresponding 2,4-xylylic nitrile. They obtained
a yield of 50-60 per cent. In the present case the yield was far
below this, about 8 grams of crude nitrile being obtained.
On boiling this for seventy-two hours with alcoholic potash,
the first separation of crystals, on cooling and crystallizing the
product from benzene, weighed 2 grams and melted sharply
from 1 87°-! 88°.

When 0.6037 gram of this amide was treated with the amal-
gam an immediate turbidity of the benzene solution resulted,
and an extremely gelatinous precipitate separated which was
difl&cult to wash. The salt is absolutely insoluble in benzene
and 87.8 per cent of the amide was converted into salt. A
sodium determination gave :

Calculated for
C]oH],NONa. Found.

Na 12.4 12.8

2,4.,6-Trimethylbenzamide and Potassium Hydrate. — It was
found that this amide readily unites with alkali in the follow-
ing way : Potassium hydrate was used, as Cohen states that
these addition-products, in the case of the substituted acetani-
lides, are more soluble than the sodium hydrate compounds.
Of this amide 0.3003 gram was dissolved in 100 cc. of ether,
in which it is readily soluble, and 2 grams of potassium hy-
drate were powdered under 40 cc. of ether and then the whole
mixed together. The mixture was shaken for half an hour
and then filtered into a weighed flask. It was washed with
100 cc. of ether and, on evaporating the ether and drying the
residue in a stream of air for a few minutes, 0.0115 gram of
unaltered amide was recovered ; 96.2 per cent had, therefore,
combined with the alkali. On treating the alkali with water
the amide was recovered.

2,4,6-Tribrombenzamide. — This was prepared from met-
aminobenzoic acid. Tribrombenzoic acid was prepared by
eliminating the amino group from this after brominating.'
Twenty grams of aminobenzoic acid gave 52 grams of the tri-
bromamino acid melting at 170°-! 72°, and this gave 43 grams
of crude tribrombenzoic acid. This was converted into the
chloride in the usual way, and, instead of attempting to

1 Volbrecht : Ber. d. chem. Ges., lo, 1708.

Sodium Salts of the Amides. 469

purify this by crystallizing from petroleum ether, in which the
compound is readily soluble, it was distilled' under a pressure
of 35-40 mm., when the chloride boiled from 2oo°-2io'', On
cooling the distillate, beautiful, four-sided tables separated,
melting at about 47°. These were crystallized from petro-
leum ether. The yield was 25 grams. The amide separated
immediately when this material was dissolved in alcoholic
ammonia, and it melted sharply from I9i°-i92°.

This amide is the most difficult to saponify of any yet ex-
amined ; nevertheless it unites with alkali to form addition-
products with the greatest ease.

2^4,6-Tribrom.benzaviide and Potassiiim. Hydrate. — 1.0040
grams of the amide were dissolved in 100 cc. ether and 2 grams
of potassium hydrate, powdered under 40 cc. of ether, were
added. After shaking for half an hour the material was fil-
tered and washed with 100 cc. of ether. On evaporating the
filtrate only 0.0145 gram of residue was obtained. Therefore,
98.7 per cent of the amide had formed an addition-product
with the alkali, and was filtered off.

2,4.,6-Tribrombenza7nide Soditcm Hydrate^
C,H,Br,CONH,.NaOH.— These addition-products can be iso-
lated in a state of purity, as follows : 4 grams of the amide
are dissolved in 150 cc. of benzene, and the solution poured
on 0.3 gram of pure sodium hydrate in a mortar (calculated
quantity 0.4 gram). The alkali is thoroughly powdered and
then the mass is filtered and washed with benzene, in which
the addition-product is insoluble. On drying rapidly in a
steam-bath, a sample thus prepared gave the following result
on determining sodium hydrate :

Calculated for
CjHjBrsCONHj.NaOH. Found.

NaOH lo.o 10.3

Under the microscope the material appeared minutely crys-
talline, but no definite form could be observed. It was abso-
lutely free from the characteristic needles of the free amide.
Water immediately decomposes the compound.

2, 4,6- Tribrom-N-dimethylbenzamide, C.H.BrjCO.NCCH,),.
— This was prepared by treating the acid chloride with an ex-

1 Sudborough : Loc. cit.

470 Wheeler.

cess of an aqueous 33 per cent solution of dimethylamine
mixed with methyl alcohol. The product thus obtained was
purified by crystallizing from a mixture of benzene and petro-
leum ether, whereupon well developed, colorless prisms sepa-
rated melting from 85°-86°. A nitrogen determination gave :

Calculated for
CsHaBrjNO. Found.

N 3.61 3.57

When 2 grams of this amide were dissolved in 30 cc. of
benzene and treated wdth 1.5 grams powdered sodium hydrate
no addition took place. The alkali was free from amide, on
filtering and washing, and the benzene solution contained no
alkali.

2,4,6-Tribronibenzoyl Chloride and Potassium Hyd?'ate.—
1. 1020 grams of the chloride w'ere dissolved in 50 cc. of ether
and 2 grams of potassium hydrate, powdered under 40 cc. of
ether, were added. After twenty minutes the mixture was
filtered, washed with 100 cc. of ether, and the ether evapora-
ted, when the residue weighed 1.0620 grams. No alkali was
found in this residue, hence 96.3 per cent of the chloride re-
mained unaffected in this treatment.

2 ,4.,6-Methyltribrombenzoate and Potassium Hydrate. — 1.0055
grams of the ester were treated with 2 grams of powdered
potassium hydrate, as above described, when 0.9841 gram of
unaltered material was recovered, or 97.8 per cent.

Thioacetanilide Sodium Hydrate, CH3CS— NHC.H^.NaOH.
— 1.2 grams of sodium hydrate (calculated 1.7) were pow-
dered under a solution of 6.6 grams of thioacetanilide in 30 cc.
of benzene. A finely divided precipitate formed at once,
which was very slow in filtering. It was washed with a little
ether and dried at about 55°, whereupon a sodium determina-
tion gave :

Calculated for
CgHsNS.NaOH. Pound.

Na 12.0 II. 8

Thioacetanilide Sodium Hydrate and Benzoyl Chloride. — 5.2
grams of the above were mixed with 3.5 grams of benzoyl
chloride in 30 cc. of ether, whereupon reaction immediately set

Alkali Carbonates. 471

in with evolution of heat. On filtering and evaporating the
ether a yellow oil was obtained, which, on standing over
night, deposited a mass of needles or prisms. When these
were washed with ether and crystallized from water broad,
colorless plates of acetanilide were obtained melting at 114''.
The yellow oil was easily recognized as thiobenzoic acid by
its peculiar, disagreeable odor. It could not be distilled even
under diminished pressure. When it was mixed with aniline
in the cold it gave benzanilide.

The above sodium-hydrate addition-product appears to be
formed when sodium alcoholate and thioacetanilide in alco-
hol are precipitated with moist ether. A portion prepared in
this manner by Dr. P. T. Walden and treated with benzoyl
chloride gave the same result as above. A determination of
nitrogen in the crystals obtained proved that the material was
acetanilide.

New Haven, Conn., February 2S, igoo.

Contribution from the Division of Chemistry, U. S. Department of Agriculture.

ESTIMATION OF AI^KALI CARBONATES IN THE
PRESENCE OF BICARBONATES.

By Frank K. Cameron.

Introduction.

In an aqueous solution sodium carbonate is hydrolyzed to a
definite extent, depending upon the concentration and tem-
perature conditions. This may be represented thus :

Na.CO^ + HOH "I NaHCO, + NaOH.

Of the four electrolytes then present in the solution only the
sodium hydroxide is dissociated or ionized to any considera-
ble extent, and in consequence the solution presents the char-
acteristic features of a solution of this substance — it is mark-
edly alkaline. Shields' has found the amount of this hydroly-
sis for a tenth-normal (N/io) solution of sodium carbonate at
25° C. to be about 3.17 per cent. For certain purposes it is
desirable to determine the " alkalinity of such a solution, that
is to say, the amount of sodium ions which may possibly re-
sult from this hydrolytic action, or one-half the sodium which

1 Ztschr. phys. Chem., 12, 167 ('iSgs)-

472 Cameron.

has been brought into the solution as sodium carbonate. This
may be done by titrating the solution with a standard acid
solution. But this procedure usually requires that the solu-
tion should be heated to the boiling temperature. At the
ordinary temperatures the acid reacts with the sodium car-
bonate to some extent to form the bicarbonate, thus :

Na,C03 + HCl = NaCl + NaHCO,,

and this formation of the bicarbonate may possibly be aug-
mented by some of the liberated carbonic acid acting on the
still undecomposed carbonate. Acid sodium carbonate is
itself neutral towards indicators, and in consequence totally
misleading results are inevitable. Furthermore, the presence
of bicarbonates in the solution, other than that formed by the
hydrolytic action of the water, will render an estimation of the
sodium alone utterly valueless. The problem has been pre-
sented in this laboratory to estimate the amount of sodium
carbonate in mixtures containing also the bicarbonate and,
further, to do this without heating the material. Many at-
tempts have been made by others to devise a method for this
purpose. That proposed by Winkler has probably proved
the most satisfactory. A good description of it has been given
by Kiister.^ But this method was not adapted to our pur-
poses for several reasons. The method of Sundstrom, de-
scribed by Lunge,' as well as that devised by Lunge^ himself,
were also found to be impracticable under the conditions
which confronted us. Without going into greater detail it
may be said that no method of which a description could be
found in the literature was free from serious objections.
This appeared most surprising in view of the probable techni-
cal value of such a method in the manufacture of sodium car-
bonate. The problem has been satisfactorily solved and an
account of the preliminary work on it may be found elsewhere.*
It was deemed advisable, however, to give the method a more
critical examination. The results are recorded in this paper.
Acid potassium sulphate is a well-characterized strong acid.

1 Ztschr. anorg. Chem., 13, 127 (1S96).

2 Ztschr. angew. Chem., 41 (1897).
& Ibid., 169 (1897).

* Report No. 64 ; U.S. Department of Agriculture, Division of Soils.

Alkali Carbonates. 473

With sodium carbonate it has been shown to react as here in-
dicated :

Na,CO, + HKSO, — HNaC03 -f NaKSO,.

The reaction-products, sodium bicarbonate and sodium potas-
sium sulphate, are neutral towards the ordinary indicators.
Therefore, by titrating a solution containing sodium carbon-
ate with a standard solution of sodium or potassium bisul-
phate, the amount of sodium carbonate present can be deter-
mined directly. Obviously the same statements may be made
regarding potassium carbonate. Many indicators have been
used with this method, but it may be said at once that, while
good results can be obtained with others, phenolphthalein
lends itself preeminently to the purposes here in view, and it
alone is now used in this work in this laboratory. It is to be
regretted that the reverse procedure from that just stated can-
not be followed, for to the majority of analysts it would cer-
tainly be easier to titrate to the appearance of color rather
than to its disappearance. But in this case such a procedure
is entirely inadmissible because the sodium carbonate, on be-
ing brought in contact with an excess of the strong acid, is
more or less decomposed, with the evolution of carbon diox-
ide, and misleading results that are not comparable are
obtained.

It has become evident, in the course of the investigation,
that acid sodium carbonate is a very unstable salt, especially
in water solutions. The sodium carbonate solutions which
had been titrated to loss of color, immediately began to color
again on standing, the rate of this " inversion" being a func-
tion of the concentration and the temperature, as well as time.
.Some solutions which had been titrated just to loss of color at
1° C. had practically no color at the end of an hour, but on
being gradually warmed over a Bunsen flame very soon be-
came strongly colored from the reaction of the regenerated
sodium carbonate on the phenolphthalein present. A tenth-
normal solution, titrated just to loss of color, at the room tem-
perature (about 25° C.) will show a marked pink color within
five minutes and a strong color within half an hour.

A solution of sodium carbonate was divided into a number

474 Cameron.

of portions in small Erienme}^er flasks, and colored by the ad-
dition of phenolphthalein or litmus. Carbon dioxide was
passed in until the solutions no longer showed any alkaline
reaction with the indicators. They were then allowed to stand
for several days. Some of the flasks were closed with rubber
stoppers. The open flasks very soon showed a strong alka-
line reaction. In the closed flasks, while a faint alkaline
color appeared within a very short time, the color became
more intense, but very slowly, showing the influence of the
carbon dioxide in retarding the inversion. Nevertheless, it
would appear that the inversion does take place, even though
some carbonic acid must be present. This phase of the sub-
ject is now being studied in this laboratory, and the investi-
gation will be continued as time and opportunit)'- may permit.
In a qualitative sense precisely similar results were obtained
with potassium carbonate and with sodium silicate, of which
both yield acid salts which are unstable in water and at once
invert to a greater or less extent. Sodium borate and di-
sodium phosphate, being salts of weak acids, give an alkaline
reaction in water solutions and can be very conveniently titra-
ted to neutrality with acid potassium sulphate, but in neither
case was any subsequent inversion observed.

Description of Experiments.

After some preliminary work it was deemed advisable to
test the method by referring all solutions to a standard alkali
solution, rather than by making the numerous gravimetric
determinations which would otherwise be required. All the
titrations were made from two burettes which previous expe-
rience had shown to be quite reliable. It was not thought
necessary to calibrate them. The burettes were graduated to
tenths (o.i cc. ) and smaller readings could be estimated. It
was thought preferable, however, not to attempt readings
closer than one-half a scale division (0.05 cc.) but to depend
upon the average of a series of readings.

The standard for reference was a solution of potassium hy-
drate, accurately prepared and carefully freed from carbonates
or other impurities. It was so prepared as to contain
18. 1 7 106 grams of potassium hydroxide per liter. A solution

Alkali Carbonates. 475

of approximately tenth-normal acid potassium sulphate was
then made up and compared with the standard potassium hy-
drate solution. It was found, as a result of a satisfactory
series of titrations, that i cc. of the potassium h3'drate solu-
tion was equivalent to 6.764 cc. of the acid potassium sulphate
solution. It follows that i cc. of the acid potassium sulphate
solution contained 0.006518 gram of the acid salt, whereas a
tenth-normal solution (N/io) would contain 0.006758 gram.

Reasonably pure potassium bisulphate is not difficult to ob-
tain. But one cannot always be certain that an otherwise
satisfactory sample contains precisely those proportions of the
elements involved, which are required by the formula HKSO^.
A small excess of either sulphuric acid or the potassium sul-
phate will not materially alter the value of the reagent for the
purposes under discussion, but it is obvious that for very ac-
curate work it is safer to determine the concentration of the
solution in the manner just described, rather than depend on
either a gravimetric determination of the sulphuric acid alone
or of the potassium it contains.

A solution of potassium carbonate (approximately tenth-
normal) was then prepared and titrated with the results here
given, the first column indicating quantity of potassium car-
bonate, the second column the quantity of potassium bisul-
phate, and the third column the ratio of the readings :

Table I.

10.00 12.70 1.270

15.00 18.90 1.260

15.00 18.90 1.260

20.00 25.20 1.260

20.00 25.20 1.260

1.262

These titrations were made in the usual manner by adding
a little of the acid solution, shaking, and waiting a few
moments to see if color disappeared before proceeding.

The potassium carbonate was then analyzed in the follow-
ing way : The solution was treated with an excess of hydro-
chloric acid, boiled to drive off all the carbon dioxide libera-
ted, and the excess of acid determined by titration with the

476 Cameron.

standard potassium hj^drate solution. The figures follow.
The first column represents amounts of potassium carbonate,
the second column hydrochloric acid, and the third column
potassium hj'drate :

Table II.

40.00 20.00 7.15

40.00 20.00 7.15

40.00 20.00 7.20

7.166

By a careful and satisfactory series of titrations i cc. of the
hydrochloric acid solution was shown to be equivalent to
1.0464 cc. of the potassium hydroxide solution. Therefore :

20 cc. HCl solution ^ 20.928 cc. KOH solution.
Excess " " = 7.166 "

40CC. Na,CO, " =13.762"
I " " " = 0.344 " "

It has been shown that i cc KOH solution was equivalent
to 6.764 cc. HKSO, solution ; therefore, 0.34400. KOH solu-
tion was equivalent to 2.327 cc. HKSO^ solution. But since
only one-half as much acid potassium sulphate is required to
convert the potassium carbonate to bicarbonate it should have
required 2.327 -r 2, or 1.163 cc, instead of 1.262 cc. as ac-
tually found. This disagreement was startling in view of the
good results previously obtained with the method.

A sodium carbonate solution of about the same strength as
the potassium carbonate solution just described was prepared
and a long series of titrations made in the same manner as
with the potassium carbonate solution. It was found that i
cc. of the carbonate solution was equivalent to 1.137 cc. of
the acid sulphate solution, though an analysis made in the
same manner as in the case of the potassium carbonate showed
that 1.035 cc. of the acid sulphate solution should have been
required. The disagreement was practically the same in both
cases.

Two series of titrations were then made with the potassium
carbonate solution. In the first series the potassium carbon-
ate solution was heated to boiling in each case before titra-

Alkali Carbonates. 477

ting. In the second series in each case the solution was filled
with crushed ice and shaken until the temperature was low-
ered to less than 1° C. before titrating. The number of cubic
centimeters of the acid sulphate solution required to neutral-
ize I cc. of the potassium carbonate solution was :

cc.

Ato°-i°C. ^ 1.455

" room temperature (about 26° C.) 1.262

After boiling (about 97° C.) 1.2 10

From these results it would appear that the reaction was
more complete at the higher temperature, in spite of the fact
that the inversion of the acid potassium carbonate is more
rapid at these higher temperatures and might be expected to
produce exactly opposite results. For instance, the solutions
which had been titrated at 97° were very strongly colored
within five minutes after the titration was completed,
while those which were titrated at 1° showed only a faint pink
color after standing for upwards of an hour. The true explana-
tion of the results, however, became apparent in the course of
these titrations. It was found that it takes a measurable time
for the reaction between the acid sulphate and carbonate to
run to end, and that if the acid sulphate is delivered too
rapidly from the burette a considerable excess may be run into
the carbonate solution before the color of the indicator disap-
pears so that, with these two effects of inversion of the acid
carbonate and the relatively slow reaction velocity between
the carbonate and acid working against each other, it would
be possible to run in the solution at such a rate as to obtain
any desired result within quite wide limits, and, in fact, beau-
tifully comparable results were thus obtained. The value of
the method would be very slight if the personal equation could
not be eliminated in the titrations. That this can be done,
however, was clearly demonstrated. If the acid potassium
sulphate solution is delivered from the burette at about the
rate of 2 drops per second, and the vessel containing the alka-
line carbonate is constantly and vigorously shaken, markedly
lower reading will be obtained than by any other procedure ;
furthermore, the readings thus obtained were found to be quite
independent of the temperature at which the titrations were

478 Cameron.

made. These facts were confirmed by several long and satis-
factory series of titrations. This point having been clearly
established, a solution of sodium carbonate was carefully pre-
pared and boiled for some time to complete the inversion of
any acid sodium carbonate which might be present. After
being cooled to room temperature and made up to the desired
volume, it was titrated with the following results : The first
column represents the amount of carbonate, the second col-
umn the amount of acid sulphate, and the third column the
ratio of the readings .

Table III.

20.00

21.50

1-075

20.00

21.60

1.080

30.00

32.30

1.076

30.00

32.30

1.076

1.077

The sodium carbonate solution was then analyzed by boil-
ing with an excess of acid potassium sulphate and titrating
the excess of acid with a solution of potassium hydrate of
known concentration. The results are here given ; the first
column indicating amounts of carbonate taken, the second
column amounts of acid potassium sulphate, and the third
amounts of potassium hydrate required to neutralize the excess
of acid :

Table IV.

20.00 50.00 5.50

20.00 50.00 5.50

20.00 50.00 5.50

20.00 50.00 5.50

5-50

1. 00 cc. KOH solution = 1.352 cc. HKSO^ solution.

5.50 " " " = 7.436 "

20.00 " Na,CO, " = 43-564 "

1. 00 " " " = 2.128 "

But since only one-half as much acid potassium sulphate
would be required to convert the carbonate to acid carbonate,
I cc. of the Na^CO, was equivalent to 2.128 cc. -!- 2 or 1.064

Alkali Carbonates. 479

cc. of the HKSO^ solution. Comparing the value found by-
direct titration, 1.077 cc, the error for i cc. was about 1.2 per
cent. More accurate results have, however, been obtained
for both sodium carbonate and potassium carbonate. This
error would amount to o.io cc. in reading for 10 cc, about
0.25 cc for 20 cc, or nearly 0.50 cc in reading a titration of
30 cc But it has been shown repeatedly that readings for
this amount could be obtained by different observers agreeing
to within less than 0.20 cc, and it may be said that the proba-
ble error for such an amount is certainly no greater than this.
Considering the number and nature of the operations involved,
the agreement obtained above was considered satisfactory, and
it was not deemed worth while to repeat the work merely for
the purpose of being able to present more refined figures.

In order to demonstrate that the presence of sodium bicar-
bonate in the salt analyzed does not affect the accuracy of the
method, mixtures of the carbonate and bicarbonate were pre-
pared. Before titrating these mixtures with the acid potas-
sium sulphate solution, the solutions of the carbonate and bi-
carbonate were separately titrated with this reagent. In
Table V the first column represents amounts of sodium car-
bonate taken, the second column the amounts of acid potas-
sium sulphate required to neutralize them respectively, and
the third column the ratio of the readings :

Table V.

10.00 8.90 0.890

20.00 17.50 0.875

30.00 26.30 0.876

15.00 13-29 0.886

10.00 8.90 0.890

20.00 17.60 0.880

20.00 17.60 0.880

30.00 26.45 0.882

30.00 26.45 0.882

30.00 26.45 0.882

0.882

A solution of sodium bicarbonate was then prepared and al-
lowed to stand until equilibrium had been reached with the

48o

Cameron.

inverted norm

lal carbonate

'.. It was

then

titrated with

suits here giv

en :

Table VI.

25.00

14.60

0.586

10.00

5.90

0.590

10.00

6.10

0.610

10,00

6.10

0.610

20.00

12.30

0.615

0.602

Mixtures were then made by adding 10 cc. of the sodium
bicarbonate solution to 20 cc. of the normal sodium carbonate
solution and titrating as before. The first column represents
the amount of acid potassium sulphate solution required, the
second column gives the reading corrected for the sodium bi-
carbonate added, and the third column the corresponding
amount of acid required to neutralize i cc. of the sodium car-
bonate solution taken :

Table VII.

23.70 17.68 0.884

23-75 17-73 0.886

23.70 17.68 0.884

0.885

The agreement of this figure 0.885 with that found in Table
V, 0.882, is very satisfactory, and may be regarded as estab-
lishing the point under investigation. It should be remem-
bered, however, that when sodium carbonate is added to a
solution containing sodium bicarbonate and consequently
some inverted carbonate, the equilibrium between the two
substances may well be materially altered. In solutions as
dilute as those examined, this displacement was probably very
small and so did not interfere with the demonstration of the
fact that the presence of acid sodium carbonate does not inter-
fere with the estimation of the hydrolyzed sodium in the solu-
tion. But when the concentrations are considerable, this
equilibrium displacement may well become an important fac-
tor. Should this method ever commend itself to use in tech-
nical work, this displacement of the equilibrium correspond-

Alkali Carbonates. 481

ing to an apparent increase of the amount of normal carbonate
present on dissolving mixtures must be considered.

An interesting extension of the method has been developed
in the course of our work. It is frequently necessary to make
a rapid determination of the chloride as well as the carbonates
in solution. This may be done in the following way : As
soon as the solution containing the carbonate has been titra-
ted to neutral action with acid potassium sulphate, a drop or
two of this reagent is added in excess to retard the inversion
of the bicarbonate to the normal alkaline carbonate. A small
amount of a solution of potassium or ammonium chromate is
then added as an indicator, and the solution titrated at once
with a standard solution of silver nitrate. Before titrating
with the silver nitrate the solution may be boiled, in which
case the inverted carbonate must again be neutralized before
making the determination for the chloride. But little advan-
tage is gained thereby, however, and results in every way sat-
isfactory have been repeatedly obtained, working throughout
at the room temperature. For instance, a solution (tenth-nor-
mal) of sodium carbonate was prepared b)' standardizing against
a tenth-normal (N/io) solution of acid potassium sulphate;
also a solution of sodium chloride, i cc. of which was equiva-
lent to 1.734 cc. of a tenth-normal solution of silver nitrate.
The following are the results obtained with the mixtures of
the sodium carbonate and sodium chloride solutions : The
first column represents amounts of sodium carbonate taken,
the second column the amounts of sodium chloride taken, the
third column the amounts of acid potassium sulphate required
to neutralize the mixtures, and the fourth column the amounts
of silver nitrate required to precipitate the chloride present.

Table VIII.

5.00 10.00 5.05 17.35

10.00 10.00 10.10 17-35

15.00 10.00 15.20 17.35

The agreement shown in these results leaves nothing to be
desired, and many more equally satisfactory determinations
have been made. An interesting theoretical point is involved
in the operation just described. The presence of normal

482 Cameron.

carbonates in the solution would, it is well known, interfere
with a titration for chloride with silver nitrate, as insoluble
silver carbonate would be formed to some extent and interfere
with the desired precipitation of the chloride. The reaction

+
is to be regarded as the result of the silver ions Ag' coming

in contact with the carbonic acid ions CO3'. But no such re-
action is to be observed in the case we have been discussing,
where acid sodium carbonate is in the solution. Therefore it
appears reasonable to assume that acid sodium carbonate does

not yield a CO3 ion, but probably dissociates, thus

NaHCO, ZZ Na + HCO3

and the ion HCO3 does not react with the silver ion to give an
insoluble compound. There is further evidence to support
this view.'

If a solution of acid sodium carbonate is added to a solution
of a barium salt there is only a little precipitate formed at
first, though the precipitation of the barium generally pro-
ceeds and is completed in time, more quickly if the solution
be heated. It has been shown that acid sodium carbonate in
water solution is unstable, some normal carbonate being
formed at once, and it is to this small amount of normal car-
bonate that the first precipitation of the barium is due. But
when this has taken place the equilibrium between the sodium
carbonate and acid sodium carbonate is destroyed, more
sodium carbonate is formed, and the precipitation of the barium
again proceeds. This action is, of course, continuous. As
the inversion of the acid sodium carbonate is more rapid at
high temperatures, the formation of the normal carbonate and
subsequent precipitation of the barium will proceed more
rapidly on heating.

The use of ammonium carbonate in precipitating insoluble car-
bonates seems worthy of consideration in this connection. Un-
like the corresponding sodium and potassium salts, ammonium
carbonate is unstable in water solution, breaking down with the

1 Walker and Cormack : J. Cheni. Soc, 47, 5 (1900) ; Foundatious of Analytical
chemistry ; Ostwald and McGowan, pp. 193 and 207.

Alkali Carbonates. 483

formation of tlie acid carbonate and the escape of some of the
ammonia as such. But an equilibrium is established between
the normal carbonate and the acid carbonate, which is de-
stroyed when the solution is brought into contact with some
salt which will precipitate an insoluble carbonate, such as
calcium or barium. The inversion of the acid carbonate is
measurably slow, however, and, as is well known, to obtain
complete precipitation the solution must be allowed to stand
for some time or be heated.

A statement of some of the preliminary experiments on the
inversion phenomena referred to may be of interest in this
connection. Three portions of a sodium carbonate solution
were titrated with acid potassium sulphate to loss of color with
phenolphthalein as indicator, allowed to stand for twenty-four
hours, and then titrated a second time to loss of color. The
results are here given, the first column being amounts of the
carbonate solution, the second column amounts of acid sul-
phate added, and the third column amounts of acid sulphate
required to neutralize the solution after standing.

Table IX.

10.00 8.90 1. 00

20.00 17-50 1.85

30.00 26.30 2.55

It would appear that the inversion was approximately pro-
portional to the initial amount of the bicarbonate, but as the
concentrations were not quite the same and the sulphates pres-
ent may have an influence, this conclusion can only be drawn
tentatively. Some measurements, which have been made by
Mr. Lyman J. Briggs, indicate that the inversion at first ap-
proaches a maximum quite rapidly, but, when equilibrium
has been nearly reached, it becomes very slow and probably
requires a long time before reaching final equilibrium.

Three portions of 20 cc. of a potassium carbonate solution
were each titrated to disappearance of alkaline reaction with
24.2 cc. of the acid potassium sulphate solution and, after
standing forty-eight hours, each required 3.1 cc. of the acid
sulphate solution to neutralize them.

Ten cc. of a sodium silicate solution required 14. i cc. of the

484 Cameron.

acid sulphate solution to neutralize it. It was immediately
boiled for three minutes, after which it required i.i cc. of the
acid sulphate solution to neutralize it ; another portion of 10
cc, to which 14. 1 cc. of the acid sulphate had been added
after the expiration of an hour, at the room temperature, re-
quired 0.9 cc. to neutralize it. The case of the sodium bi-
silicate differs essentially, however, from that of the sodium
bicarbonate, in that no volatile component can be formed. So
that this apparent inversion must be more limited in amount
and is in reality a measure of the hydrolysis of the salt. It
was not appreciable in the case of the borates or phosphates,
as has already been noted.

An application of the method to a solution of sodium sili-
cate was made. Table X gives the results of the titrations of
the solution with the acid potassium sulphate, the first col-
umn indicating amounts of the silicate solution, the second
column amounts of the acid sulphate, and the third column
the corresponding ratios :

I -550
I-550
1-570
1.580
I -550
I-570
1-573
1-573
1.570
1-572

Table X.

20.00

31.00

20.00

31.00

10.00

15-70

10.00

15.80

10.00

15-50

10.00

15-70

15.00

23.60

15.00

23.60

20.00

31.40

20.00

31-45

1.566

The solution was then analyzed by adding an excess of hy-
drochloric acid, boiling, and titrating the excess of the acid
with a solution of potassium hydroxide. The first column of
Table XI indicates the amounts of silicates taken, the second
column the amounts of hydrochloric acid added, and the third
column the amounts of potassium hydrate required to neu-
tralize the excess of acid :

Alkali Carbonates.

Table XL

40.00

20.00

11.70

40.00

20.00

11.70

40.00

20.00

11.70

48=

11.70

Since in this case the silicic acid does not escape from the
solution as does carbonic acid, when the hydrochloric acid is
added to excess, enough potassium hydrate will be required
not only to neutralize the excess of hydrochloric acid, but also
to reconvert the silicic acid to potassium bisilicate before the
solution will be alkaline.

20.00 cc. HCl solution = 20.928 cc. KOH solution.
Excess of " " = 11.700 " " "

40.00 cc. sodium silicate

solution = 9.228 "

1. 00 cc. sodium silicate

solution = 0.231 " " "

It has been shown that i cc. KOH solution was equivalent
to 6.764 cc. HKSO, solution, therefore 0.231 cc. KOH solu-
tion was equivalent to 1.562 cc. HKSO^ solution. The agree-
ment of this figure 1.562 cc. with that given in Table X,
1.566 cc, must be regarded as entirely satisfactory.

Summary,

The principal results of this investigation may be summa-
rized as follows :

1 . The amount of a soluble alkaline carbonate in a solution
can be quickly and accurately determined whether the bicar-
bonates are present or not.

2. The method seems well adapted to the estimation of
silicates, borates, phosphates, and the salts of weak acids in
general.

3. The bicarbonates are unstable in water solution and are
more or less completely converted into the normal salt.

4. Alkaline bicarbonates are themselves neutral in water
solutions ; they do not yield a CO3 ion by hydrolysis, or they
do so onl3' to a slight extent.

486 Norris and Mommers.

5. Therefore, an accurate volumetric determination of chlo-
rides by means of a standard silver nitrate solution is feasible
in the presence of alkaline bicarbonates, if the hydrolysis of
these latter is prevented.

Contributions from the Chemical Laboratories of the Massachusetts Institute of Tech-
nology.

XXV.— ON THE ISOMORPHISM OF SEIvENIUM AND
TELEURIUM.

By James F. Norris and Richard Mommers.

The fact that the most trustworthy determinations of the
atomic weight of tellurium have given results which place it
in the eighth group in the periodic system of the elements, has
led to a study of the analogies existing between tellurium and
the platinum metals on the one hand, and sulphur and sele-
nium on the other. Retgers,' in his work on isomorphism,
studied carefully the relations between sulphur, selenium, and
tellurium, and concluded that while sulphur and selenium
showed complete crystallographic similarity in their com-
pounds, tellurium was not isomorphous with either element.
The only occurrence of isomorphism between tellurium and
the elements of the oxygen family was in the case of the sul-
phides, selenides, and tellurides. These compounds crystal-
lize in the cubic system and, consequently, according to Ret-
gers, possess such a high state of crystallographic symmetry
that their power to form mixed crystals should not be taken as
a proof of the true isomorphism of their constituents. Potas-
sium tellurate is not isomorphous with potassium selenate,
but is isomorphous with potassium osmate.

Muthmann' showed later that the double bromide of potas-
sium and tellurium is isomorphous with the corresponding salt
containing selenium. Retgers^ pointed out in reply, that the
tellurium compound is also isomorphous with the analogous
platinum salt and that, as is the case with the selenides and
tellurides, the formation of mixed crystals is due to the fact
that all of the compounds crystallize in the cubic system.

1 Ztschr. phys. Chem., 8, 70; 10, 533.

2 Ber. d. chem. Ges., 26, ion.

8 Ztschr. anorg. Chem., 12, 105.

Isomorphism of Selenium a7id Tellurium,. 487

As no case of true isomorphism between selenium and
tellurium compounds has been proved, it seemed of in-
terest to question further. The crystallography of the
double bromide of platinum and dimethylamine has been
studied carefully by Hjortdahl.' The salt crystallizes in the

orthorhombic system, has the faces 00 P2 and Pco, and the
axial ratio 0.9903 : i : 0.9927. As the argument brought for-
ward against the value of conclusions drawn from the forma-
tion of mixed crystals in the cubic system could not hold in
this case, we compared this salt with the analogous selenium
and tellurium compounds. The double bromide of selenium
and dimethylamine had been prepared by one of us," but its
crystallography had not been studied. As the tellurium com-
pound had not been made, it was prepared and was found on
analysis to resemble in composition the other two salts.

The compound containing selenium crystallizes in stout,
prismatic needles, terminated by domes, which closely
resemble the platinum double bromide. The crystals of the
tellurium salt are like those of the other two salts, with the
exception that well-developed macropinacoids are present at
times. The color of the compound, however, is different from
that of the selenium and platinum salts ; the latter are nearly
alike, having a dark-red color resembling that of chromic
acid, while the color of the tellurium salt is almost that of
azobenzene.

As the facilities were not at hand for a complete crystallo-
graphic investigation, the isomorphism of the salts was
studied by applying the test of the formation of mixed crystals
in the manner devised by Retgers.^ In using this method
saturated solutions of two salts, which must differ in color, are
placed side by side on a microscope slide and then are brought
together with a glass rod. The crystals formed on evapora-
tion are examined under a microscope. If the salts are iso-
morphous, the color of the crystals varies gradually from one
side to the other, the crystals of the pure compounds being

1 Jsb. d. Chem., 1882, 474.

2 This Journal, 20, 490.

3 Ztschr. phys. Chem., 8, 6.

488 Norris and Mommers.

visible on the extreme edges of the mass. If, however, the
salts are not isomorphous, they do not mix, and in the center
where the two solutions have been brought together, distinct
crystals of each compound can be seen owing to their difference
in color. In studying the isomorphism of two colored salts,
Retgers made use of a third salt, which was colorless. If both
of the colored salts formed mixed crystals with the colorless
salt, the former were considered isomorphous with one an-
other.

As the double salts which were to be investigated were
somewhat alike in color, their isomorphism could be deter-
mined only by comparing each salt separately with a fourth
salt having a different color. The double chloride of tellu-
rium and dimethylamine was found to answer the purpose admi-
rably. The compound crystallizes in light-yellow prisms, which
have the same forms as the analogous bromide. The chlo-
ride formed mixed crystals of varying depths of color with the
selenium and tellurium double bromides, but did not mix with
the platinum compound. In the latter case the platinum salt
crystallized in small, well-defined, dark-red crystals, which
were at times overgrown with the tellurium salt. Solutions
of the selenium, tellurium, and platinum bromides were mixed
separately with a solution of the chloride and allowed to crys-
tallize. The crystals obtained in the first two cases were uni-
form in color, whereas with the platinum salt two kinds of
crystals were distinctly seen. It appears, then, that the double
bromides containing selenium and tellurium are both iso-
morphous with the chloride, and are, therefore, isomorphous
with one another. The platinum compound, however, does
not form mixed crystals with the chloride and is not iso-
morphous with the analogous selenium and tellurium salts.
The work has established the first case of isomorphism be-
tween selenium and tellurium compounds which is not open
to the objections raised by Retgers.

The existence of isomorphism in the case of the double bro-
mides appears to be inconsistent with the fact that potassium
tellurate is not isomorphous with potassium selenate. The
lack of crystallographic similarity in this case is not remark-

Isomorphism of Selenium, and Tellurium,. 489

able, inasmuch as one salt contains water of crystallization
while the other is anhydrous. In order to get further evi-
dence for or against the isomorphism of the two elements in
their oxygen acids, the cesium, rubidium, and cerium salts of
selenic and telluric acids are being prepared and studied.

In an investigation by one of us of the double chlorides and
bromides of selenium and dimethyl- and trimethylamine a
number of salts were obtained which possessed very unusual
compositions for compounds of this class. With dimethyl-
amine, compounds of the following formulae were prepared :

2SeOCl,.3(CH3),NH.HCl,

SeO,.(CH3),NH.HCl,

2SeBr,.SeBr.3(CH,),NH.HBr,

SeBr,.2(CH3),NH.HBr,

SeBr,.2[(CH,),NH.HBrJ,

SeBr,.2[(CH3),NH.HBrJ.(CH3),NH.HBr.

In order to discover if tellurium resembled selenium in the
power to form such oxysalts and perhalides, we undertook the
preparation of all the possible double chlorides and bromides
of tellurium and dimethylamine. The uncertainty about the
relation of tellurium to the periodic law noted above, adds in-
terest to any new facts brought to light and to any new
analogies established. As a result of the work, compounds
having the following formulae were prepared :

3TeCl,.TeOCl,.4(CH3),NH.HCl.H,0,

TeCl,.TeOCl,.2(CH3),NH.HCl.H,0,

TeCl,.2TeOCl,.3(CH3),NH.HCl,

TeCl,.2(CH3),NH.HCl,

TeBr,.2(CH,),NH.HBr.

A consideration of the above formulae shows that tellurium,
as well as selenium, forms double salts which contain the
oxychloride of the metal. With the more basic tellurium,
however, the tetrachloride enters into the compound. The
first three salts in the list were obtained from solutions con-
taining a large excess of tellurium. These salts, which at first
appear to have very complicated formulae, can be considered
as derivatives of the salt TeCl^.CCHJ^NH.HCl, in which a

490 Norris and Mommers.

part of the tellurium tetrachloride has been converted into
the oxychloride by the water present in the solvent froin which
the salts were crystallized. They all contain the tellurium
and the amine in the molecular ratio of i : i . In the first salt
\ of the tetrachloride has been changed into oxychloride,
in the second ^, and in the third f . The formation of the
various salts was determined by the amount of hydrochloric
acid present during crystallization.

Double salts containing selenium and the perbromide of di-
methylamine, (CH3)2NH.HBr,, were readily prepared. The
salts crystallized well from hydrobromic acid and dissolved in
water with the evolution of bromine. With tellurium bro-
mide analogous salts could not be formed. An unsuccessful
attempt was made to prepare double salts containing the
amine perbromide and platinum and lead. As far as our ex-
periments go, selenium is the only element which forms salts
of this class.

Wheeler' prepared two double bromides of tellurium and
potassium, one of which contained water of crystallization.
The double bromide of dimethylamine and tellurium was pre-
pared under conditions favorable to the formation of a hydra-
ted salt, but the resulting compound contained no water of
crystallization.

The analogies in composition exhibited by the selenium and
tellurium salts are as great as could be expected ; the differ-
ences observed are well explained by the more metallic nature
of tellurium.

Experimental.

The double salts were prepared by dissolving tellurium di-
oxide and dimethylamine hydrochloride or hydrobromide in
the corresponding halogen acid and evaporating the solutions
to crystallization. Seven different mixtures were prepared in
each case in which the proportions of the constituents varied
from 4 molecules of the oxide to i of the amine salt to i of the
oxide to 4 of the salt.

In the analyses, tellurium, halogen, and the amine were de-
termined. An attempt was made to estimate the water of crys-

1 Am. J. Sci. [3], 45, 267.

Isomorphism of Selenium and Tellurium. 491

tallization in the hydrated chlorides, but without success, for
even at 8o°-90° the salts could not be brought to a constant
weight owing to the volatilization of a part of the tellurium
tetrachloride. The presence of water was shown, however,
qualitatively. The tellurium was determined volumetrically
by the method of Norris and Fay' after the amine had been
removed by heating with a solution of sodium hydroxide. In
some of the compounds the halogen was estimated gravi-
metrically ; in the analysis of the others the volumetric
method of Volhard was used. The method was shown to be
accurate in the presence of tellurium by an analysis of the
double bromide of tellurium and potassium.

Salt of the Composition TeCl,.2(CH3),NH.HCl.— This com-
pound is obtained readily by evaporating to crystallization a
mixture of tellurium dioxide and dimethylamine hydrochlo-
ride, in the theoretical proportions, dissolved in dilute hydro-
chloric acid. The salt crystallizes in light-yellow, stout, lus-
trous needles from a hot solution. When obtained by spon-
taneous evaporation the crystals are well-developed prisms,
which are probably orthorhombic, modified by brachydomes
and macropinacoids. The salt is soluble in a small amount
of water. Excess of the solvent causes decomposition into
tellurous acid, which separates as a curdy, white precipitate.
It dissolves readily in alcohol and is insoluble in ether. The
results of the analyses follow :

I. 0.2634 gram salt gave 0.1293 gram CI by the volumetric
method.
0.3396 gram salt gave 0.0986 gram Te.
II. 0.2508 gram salt gave 0.1237 gram CI.
0-3053 gram salt gave 0.0897 gram Te.
III. 0.3910 gram salt gave 0.0813 gram (CH,)jNH.

Calculated for Found.

TeCl4.2(CH3)5NH.HCl. I. II. III.

CI 49.20 49.10 49.35

Te 29.43 29.41 29.38

(CH3),NH 20.84 20.79

Salt of the Composition TeCl,.TeOCl,.2(CH3),NH.HCl.H,0.
— When a solution containing tellurium dioxide and di-

1 This Journal, 20, 278.

492 Norris and Mom^ners.

methj-lamine hydrochloride, in the molecular ratio of three of
the former to one of the latter, dissolved in dilute hydrochloric
acid (sp. gr. 1.12), is allowed to evaporate slowly two well-
crystallized compounds are formed. The salt of the above
composition first separates in compact, almost colorless, crj's-
tals, which completeh' cover the bottom of the containing
vessel. Stout, 3'ellow needles are next formed. The two
compounds can be separated mechanical!}' without difficulty,
as the yellow cr3'stals are from 0.5-1 centimeter in length.
The compound closely resembles in composition the bromide
of selenium and trimethylamine, which has the formula SeBr^.
SeOBr3.2(CH,),N.HBr. An analysis gave the following re-
sults :

I. 0.2624 gram salt gave 0.4535 gram AgCl.
II. 0.3275 gram salt gave 0.1251 gram Te.
III. 0.3055 gram salt gave 0.0425 gram (CH3),NH.

Calculated for Found.

TeCl4.Te0Clj.2(CH3),NH.HCl.H30. I. II. III.

CI 42.74 42.79

Te 38.32 38.20

(CH3),XH 13.58 13.90

Salt of the Composition 3TeCI,.TeOCl.4(CHJ,NH.HCl.
H,0. — This salt was always formed under the conditions made
use of in the preparation of the compound described above.
The crystals were so well developed and large that they could
be obtained pure for analysis without difficulty. The salt
forms stout, columnar, rectangular, yellow crystals, whose
ends are truncated by a single plane at a sharp angle to the
prismatic faces. It was not very stable in the air, readily
losing its bright luster, and consequentl}' its crystallography
was not carefully studied. The analytical results follow :

I. 0.3056 gram salt gave 0.5767 gram AgCl.

0.3691 gram salt gave 0.1375 gram Te.

II. 0.2675 gram salt gave 0.5056 gram AgCl.

0.3 15 1 gram salt gave 0.1169 gram Te.

III. 0.3334 gram salt gave 0.0447 gram (CH3),NH.

Calculated for Found.

3TeCl4.TeOCl,.4(CH3)5XH.HCl.H20. I. II. III.

CI 46.77 46.71 46.79

Te 37.27 37.26 37.11

(CH,),NH 13.20 13.41

Isomorphism of Selenium, and Tellurium. 493

Salt of the Composition TeCl,.2TeOCl,.3(CH3),NH.HCl.—
As two salts were obtained which were derivatives of the
compound TeCl,.(CH3)5NH.HCl, in which different propor-
tions of the tetrachloride were converted into the oxychloride,
the effect of varying the concentration of the hydrochloric
acid from which the salts were crystallized, was investigated.

Tellurium dioxide and dimethylamine hydrochloride in the
molecular ratio of three of the former to one of the latter were
dissolved in the smallest quantity of concentrated hydrochloric
acid possible. After standing two months in a desiccator the
solution became very viscous and crystals separated slowly.
These were removed, but it was found impossible to purify
them for analysis. The crystals did not resemble any of the
other chlorides which had been prepared and were probably a
different compound.

To effect the greatest decomposition into the oxychloride, tel-
lurium tetrachloride and the amine salt, in the proportions
used in the experiment just described, were dissolved in water
acidulated with just enough hydrochloric acid to keep the
solution clear. After long standing a pale greenish-yellow
salt separated in the form of stout prismatic crystals, trunca-
ted by domes. A careful study of the crystallography of the
salt was impossible. It will be seen from the formula of the
salt that complete decomposition of the tetrachloride did not
take place.

The selenium compound prepared under the same condi-
tions, however, contained no tetrachloride. The results of
the analysis of the salt are as follows :

I. 0.2736 gram salt gave 0.4633 gram AgCl.
0.2987 gram salt gave 0.12 13 gram Te.
II. 0.3096 gram salt gave 0.5227 gram AgCl.
0.3060 gram salt gave 0.1240 gram Te.

Calculated for Found.

TeCl4.2TeOCl3.3(CH3)jNH.HCl. I. II.

CI 41.41 41.94 41-79

Te 40.52 40-63 40-52

Salt of the Composition TeBr,.2(CH3),NH.HBr.— A salt of
this composition was the only bromide obtained as the result
of a large number of experiments. Mixtures similar to those

494 Jackson and Fuller.

used in the preparation of the chlorides were made. From
these, crystals were obtained by slow evaporation in a desicca-
tor, by rapid concentration by heat, and in the presence of
bromine. The salt is prepared most readily by dissolving the
theoretical quantities of tellurium dioxide and dimethylamine
hydrobromide in dilute hydrobromic acid and evaporating
to crystallization. The compound can be crystallized from
water, although it is decomposed by a large ex:,ess of the
solvent. The crystallography of the salt has been described
in the first part of the paper. The analytical results follow :
I. 0.2246 gram salt gave 0.1546 gram Br.

0.5012 gram salt gave 0.0925 gram Te.
II. 0.2279 gram salt gave 0.1559 gram Br.

0-4659 gram salt gave 0.0846 gram Te.

Calculated for Found.

TeBr4.2(CH3)jNH.HBr. I. II.

Br 68.59 68.84 68.41

Te 18.24 18.46 18.15

Boston, March 9, 1900.

Contributions from the Chemical Laboratory of Harvard College.

CXVIII.— NOTE ON THE CONSTITUTION OF DI-
PARABROMBENZ YECYANAMIDE. '

By C. Loring Jackson and R. W. Fuller.

The work described in this paper consists of the conversion
of the silver salt of cyanamide into a dialkylcyanamide, and
the determination of the constitution of this body. East sum-
mer (after this work was finished) a paper appeared in the
" Berichte der deutschen chemischen Gesellschaft," in which
Wallach^ described a number of substituted cyanamides ob-
tained by the action of bromide of cyanogen on secondary
amines. For fear of approaching too near the field thus re-
served by Wallach we shall abandon the further study of di-
alkylcyanamides, but the study of alkyl compounds of dicyan-
diamide and dicyanimide will be taken up in this laboratory ;
in fact, work on this latter substance is already in progress.

Theoretically, a dialkylcyanamide derived from the silver
salt of cyanamide might have either of the following formulas :

1 Presented to the American Academy of Arts and Sciences, December 13, 1899.

2 Ber. d. chem. Ges., 32, 1872.

Diparabrombenzylcyanamide. 495

R — N=C=N — R or R^^^N — CN, and it is easy to determine
by experiment which of these two formulas is correct. So far
as we can find, but a single experiment of this sort has been
tried ; this was published some years ago by Fileti and Robert
Schiff,' who prepared diethylcyanamide by the action of ethj'l
iodide on argentic C5'anamide at 100" for some hours. The
product was extracted with ether, and divided into two por-
tions ; one was distilled, and gave a boiling-point of 186°,
whereas Cloez and Cannizzaro,^ who prepared it by the de-
composition of ethj'lcyanamide, found a boiling-point of 190°.
Fileti and R. Schiff analyzed their distillate, and obtained
carbon 60.66 instead of 61.22, and hydrogen 10. 11 instead of
10.30. The other portion of their product (which had not
been distilled) was decomposed by means of hydrochloric acid
on the water-bath ; the chlorides obtained by evaporating the
hydrochloric acid solution were converted into chlorplatinates
and crystallized fractionally, when they obtained two end frac-
tions in which the platinum was determined with the follow-
ing results :

Calculated for Found.

(NH^ljPtCl,. ((C2H3)2NHj)2PtCle. I. II.

Ft 44.04' 35.30' 42.51 36.3

(C3H5NH,)2PtCl6 requires 39.24' per cent of platinum.

In considering these results of Fileti and R. Schiff, it is to
be observed that the diethylcyanamide was not purified, and
that no very sharp criterion of purity was given (Wallach
states that these substances are decomposed by distillation un-
der ordinary pressure, so that the boiling-point is not of much
value in this respect) , further that their analyses of the plati-
num salts did not give numbers very near to those calculated.
It seemed to us, therefore, worth while to try similar experi-
ments with, if possible, a crystalline disubstituted cyanamide,
which could, therefore, be obtained in a state of undoubted
purity, and also with one which would yield amines more
easily separated than ammonia and diethylamine. We se-
lected for this purpose the diparabrombenzylcyanamide, since

1 Ber. d. chem. Ges., lo, 425 (1877).
•■2 Ann. Chem. (Liebig), 90, 95.

* These are the numbers given by Fileti and R. Schifi. They would be some-
what altered by using modern atomic weights.

496 Jackson and Fuller.

the parabrombenzyl compounds show a great tendency to
crystallize, and the diparabrombenzylamine, if formed, could
be recognized by its melting-point, 50° (dibenzylamine is a
liquid), while the parabrombenzylamine, if that were the
product, gives a carbonate with a definite melting-point, and
both these amines could be separated without difficulty from
ammonia.

The diparabrombenzylcyanamide proved to be a w^.ll-crys-
tallized solid, melting at 133°. On decomposition with dilute
sulphuric acid it gave diparabrombenzylamine, ammonia, and
carbonic dioxide by the following reaction :

(CeH,BrCHJ,NCN + 2H,0 ^

(CeH.BrCHJ.NH + NH, + CO,.

Our results, therefore, confirm those of Fileti and R. Schiff,
and leave no doubt that the dialkyl derivatives from argentic
cyanamide are cyanamides and not carbodiimides. If they
are formed by direct replacement of the silver in argentic
cyanamide by the alkyl radicals, the same constitution
(Ag^NCN) must be ascribed to this substance and to cyan-
amide. If, on the other hand, these compounds are formed
by successive additions of the alkyl bromide with splitting off
of argentic bromide, the disubstituted cyanamides could be
formed from a silver salt with a carbodiimide formula, as is
shown by the following reactions :

R

NAg Br NAg NR

^ 1/ , ^

C + RBr = C - AgBr + C

^ ^ ^

NAg NAg NAg

R
NR Br NR NR,

C + RBr = C = C + AgBr.

NAg NAg N

Our results, therefore, prove nothing in regard to the true
formula of cyanamide.

Diparahrombenzylcyanamide . 497

Preparation of Diparabrovtbenzylcyanamide,
(C,H,BrCH,),NCN.
The yellow silver salt of cyanamide, Ag^NCN, prepared ac-
cording to Walther,' was mixed with a benzol solution of
parabrombenzyl bromide in the proportion of 2 molecules of
bromide to i of the salt, which should be finely powdered.
The mixture was heated in a flask with a return-condenser on
the steam-bath, until after four or five hours the full yellow
color of the argentic cyanamide had been completely replaced
by the 3'ellowish-white color of argentic bromide. The pre-
cipitate was then filtered out and washed thoroughly with hot
benzol, and the filtrate and washings evaporated to dryness,
when a thick reddish-yellow oil was left. To purify this it
was dissolved in hot alcohol, and the strong solution allowed
to cool slowly ; a yellow oil was deposited, at first followed by
a white crystalline substance, which was obtained by pouring
the solution off from the oil as soon as the crystals began to
appear. By repeated recrystallizations of this sort the melt-
ing-point of the substance was raised to 133°, where it re-
mained constant. It was dried in vacuo and analyzed with the
following results :

I. 0.1508 gram substance gave, by the method of Carius,
0.1494 gram argentic bromide.

II. 0.3041 gram substance gave 20.2 cc. nitrogen at 18°. 6
and 760.4 mm. pressure.

Found.
I. II.

42.18

7.64

In view of the great tendency of cyanamides to polymerize,
it was thought safer to determine the molecular weight of the
body' by the method of freezing a benzol solution, which gave
the following results :

0-375 gram substance dissolved in 16.25 grams of benzol
produced a depression of o°.28 in the freezing-point.

Calculated for

(C,H6Br)5NCN. Found.

Mol. wt. 380 337

1 J. prakt. Chetn., 1896, 510.

2 This work was done before the appearance of Wallach's statement that disub-
stituted cyanamides show no tendency to polymerize.

Br

Calculated for
(C,HeBr),NCN.

42.11

N

7-37

498 Jackson and Fuller.

There can be no doubt, therefore, that the substance is
really (C,H,BrCH,),NCN.

Properties of Diparabrombenzylcyanamide.

The substance crystallizes from benzol in sheaves of white
crystals shaped like the blade of a lancet, sometimes united
laterally into groups with comb ends. It melts at 133°. It is
freely soluble in benzol, chloroform, acetone, or acetic ester ;
soluble in toluol ; slightly soluble in cold ethyl or methyl
alcohol or glacial acetic acid, freely soluble in these solvents
when they are hot ; slightly soluble in ether, carbonic disul-
phide, or in hot or cold water ; essentially insoluble in ligroin.
It is slowly decomposed by cold strong sulphuric acid ; ap-
parently unaffected by hydrochloric acid or nitric acid in
the cold. The best solvent for it is hot alcohol.

In order to see if it could form a chloride, a portion of the
diparabrombenzylcyanamide was dissolved in anhydrous ben-
zol and saturated with dry hydrochloric acid gas. No precip-
itate was formed even after the mixture had stood for two
weeks, and on evaporating off the benzol the original sub-
stance was recovered unaltered. It would seem from this ex-
periment that the diparabrombenzylcyanamide cannot unite
with hydrochloric acid.

A number of experiments were tried in the hope of obtain-
ing polymers of the diparabrombenzylcyanamide. A dilute
solution of sodic or potassic hydrate produced no effect on the
substance, either by long standing in the cold or by boiling
the mixture. The substance was boiled for two weeks with a
solution of ammonic hydrate, care being taken to replace the
ammonia which escaped, but the only change observed was
that the color turned from white to pale-brown, evidently due
to a slight decomposition, since the melting-point of the sub-
stituted cyanamide was essentially unaltered. Water alone
was also tried at the boiling-point, but produced no change.
Upon heating the substance above its melting-point it re-
mained unaltered to 160° ; above this point it turned first yel-
low, and at higher temperatures red, and on cooling gave an
oily product, which we could not bring into a fit state for
analysis. A similar viscous product was obtained when the

Diparabrombenzylcyanamide . 499

substance was heated with sodic acetate. In both these cases
it seemed evident that a decomposition had taken place rather
than a polymerization, and our experiments, therefore, con-
firm the statement of Wallach that these dialkylcyanamides
show no tendency to polymerize.

Decomposition of Diparabrombenzylcyanaviide .

As some preliminary experiments showed that the substitu-
ted cyanamide was decomposed with difficulty by hydrochloric
acid in open vessels, we adopted a dilute sulphuric acid hav-
ing a specific gravity of i .44, which has frequently given good
results in this laboratory. Several grams of the diparabrom-
benzylcyanamide were boiled with a large excess of this acid
in a flask with a return-condenser. Soon after the substance
melted in the hot acid an effervescence was observed, and
upon testing the gas given off with baryta water it proved to
be carbonic dioxide. As the oily drops did not disappear, the
heating was continued for ten hours, which reduced the
amount of oil, but did not entirely remove it. On cooling, the
whole liquid became filled with a voluminous white crystal-
line precipitate ; we determined, therefore, to stop the process
at this point and isolate this crystalline substance, which
could be easily separated from the portion undissolved
in the hot sulphuric acid. This latter substance, which
solidified on cooling, seemed to consist of undecomposed
diparabrombenzylcyanamide, as it gave a fresh quantity
of the crystalline product on boiling again with sul-
phuric acid ; its amount was insignificant. To obtain the
crystalline product it was filtered from the acid liquid, washed
with a little cold water to free it from adhering acid, and then
dissolved in hot water, which left behind the few black lumps
of undecomposed cyanamide. The solution was then filtered,
and the sulphate decomposed by the addition of a strong solu-
tion of sodic hydrate, which set free the base as a pasty mass,
solidifying on cooling. This base, after purification by crys-
tallization from alcohol, showed the constant melting-point
50°, which is that of the diparabrombenzylamine,'

(C,H,BrCH,),NH.

1 Jackson : This Journal, 3, 251.

500 Kastle.

For greater security tlie chlorplatinate was prepared and ana-
lyzed. Chlorplatinic acid added to an alcoholic solution of
the base gave a yellow precipitate, which was purified by
washing with alcohol, and dried in vacuo,

0.1783 gram salt gave, on ignition, 0.0309 gram Pt.

Calculated for
[(C7H6Br)jNH3].iPtCle. Found.

Pt 17-58 17-34

The sulphuric acid filtrate from the crystals o^ the dipara-
brombenzylamine sulphate was treated at first with sodic car-
bonate, and finally with a large excess of sodic hydrate, and
distilled with steam, the distillate being collected in a series
of flasks containing hydrochloric acid. After the distillation
was finished, the contents of the flasks were evaporated to dry-
ness on the steam-bath, and the white residue dissolved in a
little water and converted into the chlorplatinate ; this was a
yellow precipitate crystallizing in octahedra, which was
washed with water and alcohol, dried in vacuo, and analyzed
with the following results :

0.2061 gram chlorplatinate gave, on ignition, 0.0903 gram
Pt.

Calculated for
(NH4),PtCl6. Found.

Pt 43-91 43.81

It is evident from the experiment described above that the
products of the decomposition of diparabrombenzylcyanamide,
when boiled with dilute sulphuric acid, are carbonic dioxide,
diparabrombenzylamine, and ammonia. The reaction, there-
fore, runs as follows :

(C,H,BrCH,),NCN-f 2H,0 =

(C.H,BrCH,),NH + NH, + CO,.

ON THE EFFECT OF VERY LOW TEMPERATURES
ON THE COLOR OF COMPOUNDS OF BRO-
MINE AND IODINE.

By J. H. Kastle.

Some time ago the writer called attention to the fact that
the characteristic red, orange, or yellow color of bromine and
iodine compounds could probably be accounted for on the sup-

Color of Cotnpounds of Broviine and Iodine. 501

position that the halogen compounds exhibiting such colors
are slightly dissociated even in the solid state ; and that the
characteristic color, therefore, is simply that of the halogen
itself. The following facts were cited in support of this con-
clusion :

1 . The color intensity of the halogens is in inverse ratio to
their chemical activity, and may be represented roughly at
least by F<I. Similarly, the color intensity of their com-
pounds by MF<MI. Further, the color of bromine and
iodine compounds is altogether similar to that exhibited by
certain solutions of these two elements.

2. The perfect continuity exhibited in the color changes of
such easily dissociable substances as phosphorus pentabro-
mide in passing through the solid, liquid, and gaseous states.

3. Those halogen compounds are the most highly colored
which are the least stable, and whose elements are held in
combination by the weakest affinities.

4. On heating, the color of halogen compounds becomes
darker and deeper in tint.

It also follows that, if the characteristic color of bromine
and iodine compounds is due to dissociation, the color of
these compounds ought to become lighter in tint, if not alto-
gether white, on cooling to very low temperatures. At the
time of my first communication on this subject, no oppor-
tunity was afforded for trying the effect of very low tempera-
tures on the color of the compounds in question. Through
the kindness of Dr. Freer, of the University of Michigan, and
Dr. Simon, of the College of Physicians and Surgeons, Balti-
more, I have recently been able to try the effect of very low
temperatures (the boiling-point of liquid air — 190°) on the
color of certain of these halogen compounds. On the 9th of
March, Dr. Freer lectured on liquid air in the city of Louis-
ville, and on the 22nd of March Dr. Simon lectured in Cin-
cinnati on the same subject. At the close of the lecture both
of these gentlemen kindly placed at my disposal a quantity of
the liquid. The following compounds were selected for ex-
periment : Lead iodide, phosphorus pentabromide, phos-
phorus heptabromide, mercuric iodide,' iodoform, mercuric

1 other observers have found this compound to become yellow in boiling oxygen.

502

Kastle.

bromiodide, benzene dibromsulphonamide, and tribromphenol
bromide. Small amounts of these compounds in pure condi-
tion were placed in sealed tubes. These were then immersed
in liquid air in a Dewar tube and allowed to remain in the
liquid until no further alteration of color was observable.
The color of these compounds before and after cooling in
liquid air was observed to be as follows :

Substance.

Color at ordinary tem-
peratures.

Color a' the tempera-
ture of liquid air.

Ivcad iodide

golden yellow

pale sulphur-yel-
low

Phosphorus penta-
bromide

citron-yellow

white, or very pale
yellow

Phosphorus hepta-
bromide'

red

yellow

Mercuric brom-

pale yellow

white

iodide

Iodoform

yellow

white, or nearly so

Benzene dibrom-

orange

pale sulphur-yel-

sulphonanide
Tribromphenol
bromide

yellow

low
very pale yellow.

Mercuric iodide

red

orange-yellow

It will be observed that all of these compounds became
markedly lighter in color on cooling to — 190° C, and in some
cases the change of color was most striking. It would seem,
therefore, that these results tend to confirm the idea that the
color of halogen compounds is due to dissociation.

Before leaving this phase of the subject, it might be well to
call attention to an observation by Van ' t Hoff , In his ' ' :i)tudes
de Dynamique Chimique," Eng. Trans., p. 273, he points
out that at 60° C. in vacuo, silver bromide dissociates in the
sense of the equation :

2AgBr -"1 2Ag -f Br„

and that silver bromide at 60° C. in vacuo will decompose un-
til the bromine vapor evolved has reached a pressure of 2.9 X
io~53 mm.

1 This compound has hitherto been regarded as the red modification of phospho-
rus pentabromide. Kastle and Beatty have recently shown, however, that the sub-
stance is in reality a higher bromide of phosphorus, probably the heptabromide ,
PBr^.

Color of Compounds of Bromine and Iodine.

503

It would seem to be generall}'', if not universally true, that
colored substances become lighter in color on cooling to very-
low temperatures. That such is the case may be seen from
the following :

Color at ordinary tem-
perature.

dark red, opaque

steel-gray

brown

pink

sulphur yellow
dark crimson

dark blue
dark plum color
pink

violet
pink

Color at — 190°.

orange-red
steel-gray
very light yellow-
ish brown
very light pink

nearly colorless
ferruginous-brown

dark blue
pinkish violet
very light pink

pink
colorless

lighter yellow

Substance.

Bromine

Iodine, solid

Iodine, in alcoholic
solution

Iodine, in carbon
disulphide solu-
tion

Sulphur, rhombic

Phosphorus, red
modification

Copper sulphate

Chrome alum

Manganous chlo-
ride

Chromic chloride

Phenolphthalein
(alcoholic solu-
tion, alkaline)

/»-Nitrophenol(alco- 3'ellow
holic solution,
alkaline)

At the temperature of liquid air fluorescein and eosin in
alkaline alcoholic solutions retained their characteristic colors,
but became considerably lighter in tint.

From these few observations it would scarcely be logical to
conclude that the lightening of color produced by cooling to
very low temperatures is in all cases due to the same cause as
that which operates in the case of bromides and iodides. On
the other hand, it is an interesting and suggestive fact that
any increase in the depth of color produced by rise of temper-
ature is usually accompanied by a corresponding increase in
the chemical activity of the substance, and with such facts
before one, it is almost impossible to keep out of mind such
reversible processes as the following :

NjO, (colorless) ~^Z. 2NO, (reddish-brown),
and 2HI (colorless) 'ZZ. H, -\- I, (violet).

504 Kastle.

In the light of the electrolytic-dissociation theory regarding
the action of indicators, the effect of very low temperatures
on the color of an alcoholic solution of phenolphthalein which
has been rendered alkaline with caustic soda, is certainly most
remarkable and interesting.

There is still another point of interest connected with this
subject. This is regarding the effect of very low temperatures
on the color of allotropic modifications of the same substance.
It is well known that the red modification of mei curie iodide
becomes orange-yellow when cooled in liquid oxygen, and
that on removal from the bath of liquid oxygen, it quickly
changes to red again. By some chemists this has been con-
strued to mean that at very low temperatures the yellow
variety of this compound is more stable than at ordinary tem-
perature and that the yellow form of the iodide obtained by
great cooling is identical with that produced by heating above
128°.' There can be little doubt regarding the correctness of
the first of these conclusions, namely, that the yellow modifi-
cation of mercuric iodide is more stable at these very low than
at ordinary temperatures. It has been shown, for example,
that at — 35° monoclinic sulphur changes to orthorhombic
about five hundred times more slowly than at ordinary tem-
perature.^ To conclude, however, that the yellow form of
mercuric iodide obtained by cooling the red to — 190° C. is
identical with the yellow variety obtained by heating the red
to 128° is certainly incorrect, as may be seen from the follow-
ing :

Small amounts of mercuric iodide were sublimed in test-
tubes. These tubes were then allowed to stand until a cer-
tain amount of the yellow had changed to red. Both the red
and yellow varieties of this compound were thus obtained side
by side in the same tube. On placing such tubes in liquid
air, it was observed repeatedly that the red variety of the
compound became orange-yellow, and that the yellow variety
became white, or very pale-yellow. Above the level of the
liquid air the yellow modification of the compound retained
its ordinary yellow color, thereby rendering these differences

1 Newth's "Inorganic Chemistry," 5th edition, p. 558.

2 See also "The Phase Rule," Bancroft, 32-34.

Phosphorus Pentabromide . 505

in color the more pronounced by contrast. The difference in
color between the red and yellow modifications of mercuric
iodide at — 190° C. was thus rendered plainly visible. The
effect, therefore, of these very low temperatures on the red
modification of mercuric iodide is not to convert it into the yel-
low variety stable above 128°, but simply to lighten its color
in a manner characteristic of other colored bromides and
iodides. Therefore, at all temperatures below 128°, the red
and yellow modifications of mercuric iodide are distintly differ-
ent substances.

In conclusion, I desire to thank Professors Freer and Simon
for their kindness in furnishing the liquid air necessary for
these experiments.

State College of Kentucky,
lyEXiNGTON, March, 1900.

ON THE SUPPOSED ALEOTROPISM OF PHOS-
PHORUS PENTABROMIDE.

By J. H. Kastle and I<. O. Beatty.

Phosphorus pentabromide has been described as existing
in two forms. One of these is yellow and crystallizes in
rhombs ; the other is red and crystallizes in long prisms. In
the preparation of phosphorus pentabromide by adding bro-
mine in theoretical amount to phosphorus tribromide, both
the yellow and red bromides are obtained, the former, how-
ever, in much the larger quantity. In the same way both
varieties are obtained by crystallizing the compound from low-
boiling solvents, such as carbon disulphide, etc., and also by
subliming the yellow modification in sealed tubes. It has
been stated by Baudrimont' that the red variety passes into the
yellow by rubbing. Beyond this, however, but little seems to
be known concerning these substances. It was in the hope of
learning something more concerning them that this investiga-
tion was undertaken. Phosphorus pentabromide was pre-
pared by adding gradually the theoretical quantity of bromine
to phosphorus tribromide. The resulting product consisting
mostly of the yellow compound, but mixed with some little of
the red, was then sublimed in sealed tubes. Under these cir-

1 Bull. Soc, Chim. de Paris, 1861, 118.

5o6 Kastle and Beatty.

cumstances both varieties of the compound were usually ob-
tained. By subliming at 90° C, in an oil-bath, the yield of
the red compound could be considerably increased. The at-
tempt was then made to determine the transition temperature
of phosphorus pentabromide without success. On long stand-
ing the red compound was observed to change to yellow, but
at just what temperature and under exactly what conditions
it seemed at first almost impossible to determine. The first
thing to furnish a clue to the nature and relation of these two
substances was their conduct towards water. When the yel-
low phosphorus pentabromide is brought in contact with
water it can be observed to change to the white oxybromide.
This then dissolves in water, and ultimately a colorless solu-
tion is obtained. On the other hand, the red bromide dis-
solves in water apparentl}'- without the production of the inter-
mediate oxybromide, and gives a solution which has the color
of bromine water. Further, the reddish-yellow color of this
solution is permanent. In fact, some of it was heated in a
closed tube to 100° C. for several hours without any percepti-
ble alteration in color. On shaking the reddish-yellow solu-
tion with carbon disulphide, bromine is removed and a color-
less aqueous solution is obtained. It is difficult to see how
two allotropic modifications of phosphorus pentabromide could
so conduct themselves towards water. It occurred to us,
therefore, that about the only way in which to account for a
modification of phosphorus pentabromide yielding free bro-
mine on solution in water would be to suppose it to have
something of a perbromide nature, such as might possibly be
represented by the formula PBrj.Br,, in which event the com-
pound would also yield phosphorous acid instead of phos-
phoric acid on decomposition by water. Thus,

PBr,.Br,H-3H,0 = H3P0, + 3HBr+ 2Br,
whereas,

PBr, + H,0 = POBr, -f 2HBr,
and P0Br3 -f 3H,0 — H,PO, + 3HBr.

In order to test this point, small quantities of the red bromide
were dissolved in water. The cold solution thus obtained was

Phosphorus Pentabromide . 507

shaken with a small amount of zinc dust, in order to remove
free bromine. It was then filtered, and the colorless filtrate
tested for phosphorous acid by the phosphine test, and also by
warming some of it with mercuric chloride. In neither case
was any evidence of phosphorous acid obtained. It then oc-
curred to us that the red substance might possibly be a higher
bromide of phosphorus than the pentabromide. That this is
the case would seem to derive support from the following
facts : First, heat is evolved when bromine is added to phos-
phorus pentabromide ; second^, on adding a very small
quantity of phosphorus tribromide to the red compound, the
latter changes to the yellow pentabromide. This change
takes place slowly, even in the cold, and very rapidly on
warming ; thirdly, in contact with bromine vapor, crystals of
pure phosphorus pentabromide are changed to the red com-
pound with absorption of bromine ; fourthly, on sublimation,
especially at 90" C, the crude phosphorus pentabromide gives
a sublimate consisting of both the yellow and red compounds,
and a small quantity of liquid, probably phosphorus tribro-
mide, is often seen in the bottom of the tubes. On the other
hand, the yellow crystals of phosphorus pentabromide which
have been purified by sublimation, yield chiefly the yellow
compound on resublimation in sealed tubes. Small quanti-
ties of the red compound, however, have always been ob-
tained, along with the yellow, under all circumstances. On
the other hand, the red compound has been found to yield
chiefly red crystals on resublimation, only a few of the yel-
low crystals being obtained towards the end of the process.
On the supposition that a higher bromide of phosphorus, such
as the heptabromide, really exists, these changes become
readily intelligible. First, the reaction

PBr, + 2Br — PBr,
would probably be exothermic ; secondly, the formation of a
higher red bromide of phosphorus would explain the change
of color produced by the action of bromine on the yellow
phosphorus pentabromide,

PBr, + 2Br = PBr,,

and, conversely, if phosphorus tribromide were to act upon

5o8 Kastle and Beatty.

phosphorus heptabromide, it would be natural to suppose that
phosphorus pentabromide would be formed. Thus :

PBr, + PBr, = 2PBr,.
This would account for the change from red to yellow on add-
ing a small quantity of phosphorus tribromide to the red com-
pound. Fourthly, from its mode of formation from phos-
phorus tribromide and bromine, crude phosphorus pentabro-
mide might be expected to consist largely of the pentabro-
mide, together with smaller amounts of a higher bromide,
such as phosphorus heptabromide, and also phosphorus tri-
bromide. On subliming such a mixture in sealed tubes, a
separation of these constituents might be effected. Such, in-
deed, has been observed to be the case. Then again, phos-
phorus pentabromide and phosphorus heptabromide both un-
dergo dissociation readily \vhen heated. Hence, such changes
as the following would be possible, even on subliming the
pure compounds :

PBr, = PBr, + 2Br,
and PBr, + 2Br — PBr,,

and in case of the red compound,

PBr, — PBr, + 2Br.

These facts would certainly seem to indicate the existence of
a higher bromide of phosphorus having a red color. The at-
tempt, therefore, has been made to isolate this higher bro-
mide in a state of purity. A small quantity of phosphorus
pentabromide, together with the theoretical amount of bro-
mine to form phosphorus heptabromide, were heated in a
sealed tube. On keeping this mixture at 90° for sometime, a
sublimate consisting of prismatic red crystals was obtained.
This compound gave the following numbers on analysis :

Calculated for
PBr,.

Found.

p

Br

5-25
94-75

5-40
96.20

Total 100.00 101.60

Considering the difficulties in the way of handling the com-

Ethyl Anilinomalonate . 509

pound, it will be obsen^ed that these figures agree fairly well
with those required by the theory for phosphorus heptabro-
mide. Phosphorus heptabromide has usually been obtained
in the form of bright-red, transparent, prismatic crystals.
Under some circumstances it has been found to resemble
chromium trioxide, or arsenic triiodide in general appearance.
It is very unstable and seems to undergo dissociation even at
ordinary temperatures. Hence, it is best preserved in sealed
tubes. On standing in contact with bromine absorbents, it
gradually loses its red color and passes to the yellow penta-
bromide. On rubbing, it also loses bromine and becomes yel-
low. This would explain the apparent change of the allo-
tropic red modification of phosphorus pentabromide into the
yellow, as described by Baudrimont. In our work on this
substance we have seen certain indications of still other higher
bromides of phosphorus. It is our intention to investigate
these substances more fully.

State College of Kentucky,
Lexington, April, 1900.

Contribution from the Chemical Laboratory of Hobart College.

ON THE ACTION OF NITROUS ACID ON ETHYL
ANILINOMALONATE.

[PREIvIMINARY REPORT.]
By Richard Sydney Curtiss.

In a former paper' I described a peculiar oxidation of ethyl
anilinomalonate, which was effected by treating the substance
dissolved in ligroin with mercuric oxide. This resulted in
the formation of ethyl dianilinomalonate. This same change
can be brought about with other oxidizing agents. The
mechanism of this reaction I will report upon later.

Of especial interest is the behavior of ethyl anilinomalonate
with nitrous acid. I will give a brief account, at this time,
of experiments now under way, in order to be allow^ed to con-
tinue this line of research undisturbed, and will report results
in full in this Journal in the near future.

1 This Journal, 19, 691.

5IO Curtiss.

If etnyl anilinomalonate, C^H.NH — CH^ , in sus-

pension in water, is carefully treated with sodium nitrite and
sulphuric acid, a thick, clear, amber-colored oil is obtained.
A molecular weight determination made with a carefully
prepared sample of the oil gives, by the freezing-point method,
in pure benzene :

Molecular weight
found.

Theory for
CoHj— N— NOH
\/
CjHjOjC— C— COjCjHs

r ist det.
(i) ^ 2nd det.
( 3rd det.

259

280

264

268

(2) ist det.

253

This body is extremely unstable, and, if not carefully freed
from traces of impurity, it quickly dissociates on standing,
even by contact with traces of pipe- water residue on the flask,
or with bits of broken glass. Even when pure it loses nitric
oxide gas on standing in the sunlight, or when slightly
warmed. It does not give I^iebermann's nitroso reaction

/ .CO,R

I for C.HjN — CHC^ ) . It has, moreover, marked acid

^ I \CO,R^

NO
properties, giving a well-crystallized, but unstable, sulphur-
yellow potassium salt when treated with a solution of potas-
sium hydrate. This salt decomposes near 118° with evolution
of gas.

Theory for
CgHj— N— NOK

\ / . Found.

CHsOjC— C— CO,C,H,

K 12.26 11.60

Sodium hydrate yields an equally well defined and unstable
canary-yellow sodium salt, which decomposes, when quickly
heated, at Ii8°-i22° with evolution of gas.

Theory for
CoHj— N— N.ONa

\/ . Found.

CjHsOjC— C— COjCjHs

Na 7.28 7.41

Ethyl Anilinomalonate. 511

From the sodium salt au insoluble white silver salt can be
made with silver nitrate. The clear, yellow, aqueous solu-
tions of the sodium and potassium salts decompose, even in
the cold, in an hour or two, and a clear yellow oil separates,
having a marked odor like an isonitrile. From this oily emul-
sion, white needles separate in a few days.

Metallic sodium gives a light-yellow sodium salt with evo-
lution of hydrogen. A solution of sodium carbonate is quickly
colored yellow but appears to act but slightly on the oil.
Ammonium hydrate gives a still less stable crystalline salt,
which is entirely decomposed to ammonia and a clear yellow
oil at 35°-37° in ether solution.

Ferric chloride, in alcoholic solution of the acid oil, gives a
deep-red color. Concentrated mineral acids turn it red. Sul-
phuric acid liberates oxides of nitrogen. Hot concentrated
hydrochloric acid causes an evolution of gas and gives a
marked odor of phenol.

Treated with acetic anhydride at ioo°-i4o°, 4 grams of the
clear amber oil gave i gram of white needles (ra. p. 114°) ;
2-3 grams of clear, neutral, thick oil, and 120 cc. of a color-
less gas, which is in large part nitric oxide, turning red in the
air with formation of nitrogen peroxide. A molecular weight
determination made with this body (constant m. p. 114°) gave
in pure benzene by Beckmann's boiling-point method :

Substance.

Molecular weight for
Molecular C.Hs— N— NO.(COCH,)
weight \/
found. CjHsOjC— C— COjCjHs

Gram.

ist det.

0.0593

264 322

2nd det.

0.1003

334

3rd det.

0.1383

346

operating in apparently the same way on another sample of
the oil, a crystalline body was obtained of constant m. p. 111°
on recrystallization from alcohol, and none of the 114° m, p.
crystals. The average of four closely agreeing molecular
weight determinations made with this substance (m. p. 111°)
gave 222 as the molecular weight found.

These two neutral products, obtained by the action of acetic
anhydride are quite stable, decomposing near 200°.

512 Chambers and Frazer.

Reduction of the acid oil in dilute alcoholic solution by-
sodium amalgam results in loss of nitrogen in the form of am-
monia and formation of a small amount of an orange-colored
crystallized body. As a quantity remained, insufficient for
analysis, of the substances on which the molecular weight de-
terminations were made, no definite conclusions are drawn
from the above results at this time.

C.H— N— N.OH(M)

\/

The formula C is suggested as possibly

/\

HAO,C CO,C,H,

the correct one for the amber-colored oil and its salts.

I shall make a thorough study of this interesting substance
and its derivatives, as well as of the behavior of other nega-

yCOOR
tively substituted derivatives (R) — N — C<^ , with oxi-

I I \COOR
H H
dizing agents, and report the results in this Journai,.

HoBART College, Geneva, N. Y.,
April i8. 1900.

ON A MINIMUM IN THE MOLECULAR LOWERING
OF THE FREEZING-POINT OF WATER, PRO-
DUCED BY CERTAIN ACIDS AND
SALTS.

By Victor J. Chambers and Joseph C. W. Frazer.

The molecular lowering of the freezing-point of water by
dissolved substances, would be expected to remain constant
as with non-electrolytes, or to increase with increase in dilu-
tion as with electrolytes. With non-electrolytes the molecular
lowering does remain very nearly constant with increase in
the dilution of the solution, after a certain dilution is reached,
but it has long been known' that the molecular lowering of
substances like cane sugar increases very considerably with
increase in concentration from a certain point. In a word,
there is a well-defined minimum in the molecular lowering
produced by such substances.

1 Arrhenius : Ztschr. phys. Chem., 3, 495 ; Jones : Ibid., la, 642.

Molecular Lowering of the Freezing-point of Water. 513

In the case of electrolytes, there were, until very recently,
but few substances' with which such a minimum was sus-
pected. Jones and Chambers^ have, however, pointed out a
number of substances in which a minimum in the molecular
lowering of the freezing-point undoubtedly exists. They
studied in this connection the chlorides and bromides of mag-
nesium, calcium, strontium, and barium, and plotted the re-
sults obtained in curves. These showed very clearly the
presence of the minimum in the molecular lowering, and this
minimum occurred for the different compounds at approxi-
mately the same dilution — from one-tenth to two-tenths normal.

The conductivities of the same solutions of these com-
pounds were measured and the results likewise plotted in
curves. The conductivity curves, unlike the freezing-point
curves, were perfectly regular, showing no sign of any mini-
mum at any concentration. The dissociation of these sub-
stances thus continued to increase with increase in dilution,
with perfect regularit}'', as is shown by the regular increase
in the conductivity. Taking into account all of these facts,
and, further, that the chlorides and bromides of the alkaline
earths are, in general, very hygroscopic substances, Jones
and Chambers offered the following suggestion as a possible
explanation of the abnormally great lowering of freezing-point
produced by the above compounds in concentrated solutions.
" In concentrated solutions these chlorides and bromides must
take up a part of the water forming complex compounds with
it, and thus removing it from the field of action as far as
freezing-point lowering is concerned. The compound, which
is probably very unstable, formed by the union of a molecule
of the chloride or bromide with a large number of molecules
of water, acts as a unit or as one molecule in lowering the
freezing-point of the remaining water. But the total amount
of water present, which is now acting as solvent, is dimin-
ished by the amount taken up by the chloride or bromide
molecules. The lowering of the freezing-point is thus abnor-
mally great, because a part of the water is no longer present
as solvent, but is in combination with the chloride or bro-
mide molecules.

1 Arrhenius : Ztschr. phys. Chem., 3, 496.
* This Journal, 23, 89.

514 Chambers and Frazer.

But the conductivity results must also be taken into ac-
count. These show, unmistakably, a marked degree of dis-
sociation even in the most concentrated solutions employed.
There must, therefore, be a certain number of the molecules
broken down into ions, either by the water acting as solvent
or by the water in combination with the molecules, just as
salts are probably dissociated in their water of crystallization. ' '

Jones and Chambers point out, further, that there are un-
questionably hygroscopic substances known which combine
with water in concentrated solution. This is especially true
in the case of sulphuric acid, where well-defined compounds
are known.

The object of the present investigation is to study other
hygroscopic substances, to see whether very different classes
of compounds show this abnormally great freezing-point low-
ering in concentrated solutions. The compounds with which
we have worked are hydrochloric acid, phosphoric acid,
sodium acetate, zinc chloride, strontium iodide, cadmium
iodide, and copper sulphate. These substances were purified
by the methods best adapted to each case, and solutions pre-
pared and standardized. In standardizing the solutions that
constituent was chosen which could be most accurately and
readily determined. From the standard solution the remain-
ing dilutions in each case were directly prepared.

The method employed in measuring the freezing-point low-
ering was essentially the Beckmann method. We were care-
ful to keep the temperature of the freezing-bath only a little
below the freezing-temperature of the solution. The results
which we obtained are given in the following tables. Column
I gives the concentration in terms of normal, column II the
freezing-point lowering observed, column III the correction to
be introduced for the separation of ice, which concentrates the
solution, column IV, the corrected freezing-point lowering,
and column V the molecular lowering of the freezing-point :

Molecular Lowering of the Freezing-point of Water. 5 1 5

Table I.
CuSO,.

I. II. III. IV. V.

0.476 o°.722 o°.oo8 o°.7i4 1.50

0.595 o°.885 o°.oi9 o°.866 1.45

0.890 i°.300 o°.o25 i°-275 1.43

1. 190 i.°795 o°.055 i°.74o 1.46

Table II .
H3PO,.

I.

II.

III.

IV.

V.

0.II8

0°.282

o°.oo8

o°.274

2.32

0.236

o°.545

o°.oio

o°-535

2.26

0.472

i°.o65

0°.026

i°.039

2.20

0.944

. 2°. 176

o°.033

2°. 143

2.27

1. 41

3°.4io

o°.o6i

3°. 349

2.37

1.62

4°.27o

o°.o57

Table III.
HCl.

4°. 213

2.60

I.

II.

III.

IV.

V.

0.051

o°.i87

0°.002

o°.i85

3-63

0.102

o°.36o

o°.oo7

o°.353

3-46

0.204

o°.755

o°.oio

o°.745

3.65

0.408

i°.565

o°.030

i°-535

3-76

0.516

2°. 003

o°.o47

i°.956

3-79

1.032

4°.33o

0°.092

Table IV.
CH3C00Na.

4°. 238

4.10

I.

II.

III.

IV.

V.

0.058

0°.2l6

o°.oo5

0°.2II

3-64

0.II6

0°.42I

o°.oo8

o°.4i3

3-55

0.174

o°.650

0°.022

o°.628

3.61

0.232

o°.86i

o°.oi6

o°.845

3-64

0.348

I°.3I2

o°.o33

i°.279

3-67

0.464

i°.774

0^.038

i°.736

3-74

5i6

Chambers and Frazer.

Table V.
CdL.

I.

II.

III.

IV.

V.

0.133

o°.3i5

o°.ooi

o°.3i4

2.36

0.222

o°.48o

o°.ooi

o°.479

2.16

0.333

0°.720

o°.oio

o°.7io

2.13

0,444

i°.oo5

o°.oo8

o°.997

2.24

0.666

i°.575

o°.oii

i°.564

2.35

0.888

2°. 245

o°.oi8

Table VI.
Sri,.

2°. 227

2.51

I.

II.

III.

IV.

V.

0.027

o°.i43

o°.oo3

o°.i40

5.18

O.C54

o°.28o

0^005

o°.275

5-09

0.081

o°.425

o°.oio

o°.4i5

5.12

0.108

o°.572

o°.oi4

o°.558

5.17

0.162

o°.863

o°.oi9

o°.844

5-21

0.216

i°.i8o

0°.024

i°.i56

5.35

0.327

i°.855

o°.05i

Table VII.
ZnCl,.

i°.8o4

5.51

I.

II.

III.

IV.

V.

0.0493

0^.270

o.°oo7

o°.263

5-33

0.0986

0°.52I

0.'0I2

o°.509

5-16

0.197

i°.o45

0.°025

I°.020

5.17

0.296

i°.585

0.°042

i°.543

5.21

0.394

2°. 138

o.°o40

2°.098

5-32

0.592

3°.272

o.°05i

3°.22I

5.44

These results are plotted in curves (Figs. I-III). The ab-
scissae are concentrations, the ordinates molecular lowerings
of the freezing-point. The more dilute solutions were not in-
vestigated in this work, since it is well known from previous
work that the molecular lowering increases with the dilution
in dilute solutions. We have, therefore, carried our measure-
ments only a little beyond the minimum in the molecular low-
ering.

There is no very pronounced minimum in the case of cop-

Molecular Lowering oj the Freezing-point oj Water. 517

per sulphate, but the minimum for phosphoric acid comes out
very sharply at about five-tenths normal. The minimum ap-
pears for hydrochloric acid and sodium acetate between one-

fis.l.

*^

\

\

^^

■^

-^

^

\^

^

/"

-^

^

J« ,

c.

,5C

^ .

^

^

-*

^6

e/
eo

/.6

/.6
/.6
/.4
/.J

/./
/.O
.&

/.6 /A /.e /.o .s .6 .4? .^ o

tenth and two-tenths normal, while for cadmium iodide it ex-
ists at a slightly greater concentration. The minimum oc-
curs for strontium iodide and zinc chloride in the region of a
one-tenth normal solution.

In all the cases above described, with the possible exception
of copper sulphate, there is an unmistakable minimum in the
molecular lowering of the freezing-point, and from this mini-
mum the molecular lowering increases with increase in con-
centration. Nearly all of these substances have a considera-
ble attraction for water. This is shown by a number of these
substances in the strong tendency to unite with water when

r,i8

Chambers and Frazer.

4.0

*^

•\

^

\

•*

q\

^

is.

/

3.5

><>

\

/

^

{

3.0

e.5

V

s^

""

v<

'OV

/

X

N

/

V

U

pn

w

.8

.6

^.2 0

they have been freed from it. This is especially true with
hydrochloric and phosphoric acids, and sodium acetate and
zinc chloride. In other cases, as with copper sulphate, the
attraction for water expresses itself in the water of crystalliza-
tion in the salt.

We attempted to study disodium phosphate in the same
way that we have investigated the above salts, but we w^ere
compelled to abandon the attempt because of the comparative
insolubility of this compound at low temperatures.

It seems from the above results that the suggestion of Jones
and Chambers to account for the minimum in the molecular

Molecular Lowering of the Freezing-point of Water. 519

S.5

6.4

5.>3

n

•<<;,

\

^

^

N

\

■n

\

\

V^

^,

\

\

S,

\

*

\

^5

V

J>

/

^5

^

■^

J

\

r

\

.6

lowering of the freezing-point of water produced by a number of
electrolytes, is in the main substantiated b}^ the facts. Indeed, it
seems to be the only explanation possible up to the present, if
we take into account both the freezing-point lowering and
conductivity of these concentrated solutions. At present we
seem forced to the conclusion, that in the verj' concentrated
solutions of certain electrolj'-tes there is some kind of union
between the molecules of the dissolved substance and of the
solvent. This view put forward by Jones and Chambers to
account for the abnormal freezing-point lowerings which they
had discovered, should be carefully distinguished from the
attempt which was made a few years ago to account for all
solutions on the basis of a combination taking place between
the solvent and the dissolved substance. This latter view
was meant to apply to all solutions, dilute as well as concen-
trated. In dilute solutions we have not the slightest reason
to suppose that there is any union between the solvent and
dissolved substance, but, on the contrary, the very best evi-
dence that no such union exists. In this connection we have
but to refer to the fact that dissociation, as measured by the
freezing-point method, agrees with dissociation as measured
by the conductivity method ; or to the general applicability of
the law of Kohlrausch to all solutions of all electrolytes.

520 Report.

Whether the view of Jones and Chambers should prove to
be the final expression of the truth, in connection with con-
centrated solutions of electrolytes which show a minimum in
the molecular lowering of the freezing-point, can be decided
only by further work. But it is quite certain that any
general theory of solutions must take into account such re-
sults as those previously described by Jones and Chambers,'
and as recorded in this paper.

It was early pointed out that the laws of gas pressure do
not apply to the osmotic pressure of concentrated solutions,
and for this reason, if for no other, comparatively little prog-
ress has been made in the study of concentrated solutions
from the physical-chemical standpoint. It seems to us quite
possible that work of the kind here described may help, if
only a little, towards the understanding of concentrated solu-
tions, and we may thus be able to find out why it is that the
laws which obtain for dilute solutions do not hold in the more
concentrated. It is with this hope in mind that further work
along the above line will be done.

In conclusion we wish to express our thanks to Dr. H. C.
Jones, at whose suggestion the above investigation was under-
taken, and under whose guidance it has been carried out.

Chemical Laboratory,

Johns Hopkins University,

January, 1900.

REPORT.

The Yearns Advance in Techiiical Chemistry .

The year just passed has been perhaps the most important
of the whole century in the advance made in all manufactur-
ing industries, especially those having a chemical basis.
This advance has been brought about, in a few instances, by
the application of radically new methods, but more often
by a wonderful enlargement of the scale of operations of well-
tried processes, and by the general introduction of automatic
mechanical devices and labor-saving machinery. Every-
where the striving for increased tonnage and for getting the
very largest possible yield out of each piece of apparatus em-
ployed, has been more intense than ever before.

1 Loc cit.

Report. 521

Considering first the industry which is of greatest commer-
cial and economical importance in the United States, the
metallurgy of iron and steel, the most striking change is the
practical doubling in capacity of most of the newly designed
blast-furnaces. The daily output of the coming furnace must
approach 600 tons of pig-metal, while the maximum for most
furnaces heretofore has been a daily average of from 200-300
tons. When we consider that only a decade ago an output of
100-150 tons daily was considered good practice, we can ap-
preciate the magnitude of the change and wonder where the
limit of the future is to be. The greater part of this increase
has been caused by doubling, or more than doubling, blast
pressures and blast quantity, thereby increasing the yield of
existing furnaces and rendering possible larger hearth diame-
ters.

A considerable increase of economy in the use of fuel for
making pig-iron seems to have been accomplished abroad by
the direct use of furnace gases in gas-motors for producing
the air-blast, instead of burning this gas to generate steam
and using steam-engines to operate the blast pumps. The
solution of this problem is cause for congratulation, because
of the numerous difficulties connected with it. The gas from
iron-furnaces available for such motors contains only about 25
per cent of carbonic oxide, as almost its whole source of heat
value, besides carrying large quantities of fine dust of coke,
ore, etc., which greatl)' increases the difficulty of use in any
mechanism where corrosion must be avoided. Any one who
has seen the valves of a hot-blast stove cut through and worn
out in a few months \>y the action of this dust will appreciate
its cutting power.

In Scotland, furnaces using raw coal have made as a b)'-pro-
duct about a tenth of all the ammonia produced in Great Brit-
ain during the j^ear. Certain localities in the United States
possessing abundant non-coking coal in proximity to cheap
and good ore, might profitably adopt this method of iron manu-
facture, notably the new Michigan coal district of the Sagi-
naw Valley, which, by this means, could easily supply the
whole of the iron used in Michigan districts and all of the am-
monia needed in the newly developing alkali industries of that
locality.

Another important factor in the great increase of furnace
capacity for the production of pig-iron has been the installa-
tion of automatic labor-saving devices for handling furnace-
charges and removing furnace products. The most important
of these are the car and ore-loading machines of Brown, Mc-
Myler, Lindsey, and Hulett, the casting machine of Uehling

522 Reporl.

for handling the metal, and the various methods for carrying
charges to the furnace top, with automatic dumping and dis-
tributing devices. These latter have removed the necessity
for charging men or any laborers continuously at the charg-
ing level, where the work is exhausting and dangerous. By
the use of a double bell they effect a thorough mixture of the
charge and prevent the loss of furnace-gases.

The successful conversion of blast-furnace slag into a fair
quality of hydraulic cement at a number of furnaces is a long
step toward the economical solution of the troublesome prob-
lem of the disposal of this vast by-product. It has been found
that certain grades of basic slag in which the proportion of
magnesia and sulphur is not too high, by simply being granu-
lated with water as they flow from the furnace, ground ex-
tremely fine and intimately mixed with the proper proportion
of lime, are converted into a hj^draulic cement which forms a
cheap and, under certain conditions, an excellent substitute
for Portland cement, and for which a permanent demand has
been created.

In the production of steel the gap between the cost of pro-
ducing Bessemer and open-hearth metal has been further less-
ened, mainly b}' the general introduction of basic open-hearth
furnaces of greatly increased capacity and of labor-saving de-
vices in charging metal and fluxes. Most important of these
latter is the charging machine of Wellman. In this connec-
tion, too, the large introduction of the Wellman tilting open-
hearth furnace during 1899 is worthy of mention, and a prob-
able further econom}' of operation will be secured by their use.
Several large plants using these tilting furnaces have been in-
stalled during the past j^ear, and, while they have been used
in a number of places heretofore, the record of their efficiency
has not as yet been made public and is awaited with great in-
terest. While their cost of construction is about 25 per cent
more than that of the older stationary type, the complete re-
moval of all metal and slag from the furnace hearth at each
operation, with the resulting saving of metal, the saving of
the time necessary for tapping, the small amount of repair
necessary to the bed after the removal of each charge, and the
facility with which this can be accomplished are factors which
will probably cause this to become the standard type of steel
furnace of this decade.

In Bessemer practice the most noticeable improvement is
the general introduction of the Jones mixer for receiving the
molten pig-metal direct from the furnace, thus saving its con-
tained heat and doing away with cupolas for melting the iron
previous to its treatment in the converter. This method ef-

Report. 523

fects not only a saving in heat or fuel, but a greater gain in
the cost of handling the iron. It has been found that only
about one laborer in a hundred can endure the strain of con-
tinuously handling the heavy pigs of metal at the blast-furnace
in their removal from the sand molds and loading on cars.
The doing away with this severe labor by the direct use of
hot metal in the Bessemer plant and by the use of the Uehling
casting machine seems, therefore, a gain to humanity as well
as in the money value saved. The basic converter still fails
to gain a permanent foothold in this country, and, because of
our immense deposits of pure ore and beds of phosphate rock,
and of the continued encroachments of the open-hearth pro-
cess, probably never will.

The metallurgy of copper has undergone changes similar to
those of iron, only in a much smaller degree. The most im-
portant of these are the increased use of the Bessemer con-
verter in refining mattes, and an increased output of electro-
lytically refined metal. The general use of a gold-bearing
material as a lining for the converter in matte Bessemerizing
has effected a material economy. In roasters for copper sul-
phide ores, several new devices have gained general use. A
Denver-made modification of the old Spence furnace, with its
numerous beds and automatic plow rakes, in which the opera-
ting chains are placed upon the exterior of the hearth, and
the Herreshoff furnace, consisting of a vertical cylinder with
horizontal diaphragms or beds and rakes operated by a cen-
tral shaft, have perhaps received the largest installment dur-
ing the year. A plant of considerable size to operate the
Hoepfner process of refining copper has been in operation for
some time, but reliable cost data are not at hand. This pro-
cess depends upon dissolving the oxidized metals with cupric
chloride and electrolyzingthe chloride solution. The process
was tried at the Brooklyn experimental plant of a copper-
nickel refining company some years ago, but was abandoned.

In the metallurgy of nickel the principal event has been the
installation in England of a considerable plant to use the
Mond process of refining by carbonic oxide, and of a plant in
this country utilizing a new but unpublished process. Storer's
method proposed, but not yet installed on a commercial basis,
applies the old Hunt and Douglass copper method to nickel
ores, treating nickel oxide at high temperature with a strong
solution of ferrous chloride.

In the treatment of lead, tin, silver, mercury, and zinc ores,
changes during the year seem to have been unimportant.
Several methods have been proposed for treating the low-grade
argentiferous blende-galena ores, so common in Colorado, but

524 Report.

none has as j^et stood the test of successful commercial ap-
plication.

The output of gold has been further increased by the in-
stallation of man}^ new cyanide works, much of the material
treated in these mills being the tailings from old amalgama-
tion plants or of abandoned dump heaps. Electrolyzing the
C3^anide solutions in this process is becoming more common.
The Sulman-Teed method of adding a small quantity of cyan-
ogen bromide to the lixiviating solution is claimed to effect
increased gold extraction, especially in arsenic-bearing ores,
but it is also asserted by many that the loss of cyanogen by
this method is too great for success, and more time must be
allowed for further evidence. A method of assisting the free
access of the oxygen probably necessary to the solution of
gold by cyanide solutions, which consists in violently agita-
ting the ore with the solution by means of air introduced into
the mixture under considerable pressure has been patented
and is now being largely advertised under the name of the
" Pneumatic Process." A possible serious objection to the
use of this method is that an increased loss of cyanide may
occur from excessive oxidation and decomposition by carbonic
dioxide. During the years immediately following the marked
success of the cyanide process in South Africa, the tendency
was to introduce this method for all sorts of ores and under all
sorts of conditions, whether adapted to success in this way or
not. Now, the proper limitations of the use of cyanide solu-
tions are better understood, and the chlorination process is
again receiving more attention, so that the two methods are
now beginning to assume their proper and normal relation to
each other. Increasing amounts of gold and silver are being
recovered by matting the ores with copper- and sulphur-bear-
ing material, Bessemerizing this matte to blister copper, and
electrolyzing the product.

In several industries the 5^ear has been marked b}^ the be-
ginning of that vast shifting of location from coal to water-
power situations, which is to mark the coming decade. In
several cases this shifting has already been nearly completed,
notably in the production of chlorate. Norway, Scotland,
Switzerland, and the mountain regions of France and the
United States, where water-falls abound, are destined to be-
come centers of manufacturing activities fully as great in many
industries as the older coal localities, and with the advantage,
that the coal fields once exhausted are gone forever, while
water powers last for all time. This recent great develop-
ment of the uses of water-power is due to new electrolytic pro-
cesses, to material improvements in the transmission of high-

Report. 525

tension currents, to improvements of dynamos, and to the de-
velopment of water-turbines to utilize extreme pressures.
This transference of many old industries to water-power dis-
tricts will be limited only by the cost of carriage of the raw
material to the plant, and of the finished product to its mar-
ket. The competition with coal-generated power thus occa-
sioned must result in a more and more economical use of fuel,
and the year has shown material progress here. The pre-
viously mentioned use of blast-furnace gases in gas-motors is
of this nature, but the verj^ large year's increase of by-product
coke-oven plants is of greater significance. In America new
ovens of the Semet-Solvay or the Hoffman type have been
started during the year at Halifax, Boston, Glassport, Pa.,
Benwood, W. Va., and Ensley, Ala. This is a satisfactory
improvement, because the wasteful use of coal in bee-hive
ovens will always remain a reproach of the 19th century, es-
pecially in American and English practice. These by-prod-
uct coke ovens effect an increase of from 10 to 15 per cent in
the amount of coke produced, with a saving of 3-4 per cent of
the weight of coal tar, 0.4-0.8 per cent ammonium sulphate,
and 7-10 per cent gas in excess of that required for coking.
These last three items almost equal in value the coke pro-
duced.

The skill and care required in operating the Mond gas-pro-
ducer, considerable fluctuations in the price of tar and ammo-
nia, and the high cost of construction and depreciation of
plant have restricted the introduction of this most valuable
invention to a few localities, but a number of such plants
have been started during the year and with considerable suc-
cess. Probably the most important progress in the use of
fuel and our greatest present hope of delivery from the smoke
domination in soft coal districts, lies in the success of the
Dellwick water-gas process which the past year has shown.
In this device the fuel is burned directly to carbonic dioxide
during the heating, or air-blast period, by using extra high
blast pressure, and skillfully distributing its contact with the
fuel. This increases the gas yield by nearly 100 per cent,
and reduces the total loss of the heat value of the fuel from
55 to only 18 per cent. During the past year a plant has been
installed in Pittsburg for the conversion of coal into fuel gas,
utilizing a radically new method, which also bids fair to solve
this important fuel question, and the result of this experiment
is awaited with intense interest.

In man}^ instances, where petroleum has been used as fuel,
its recent increased cost has forced its abandonment. This
has made the discovery of an equally convenient and efl&cient

526 Report.

fuel a great desideratum. Fortunately such a substitute for
oil has been found in the use of finely-powdered bituminous
coal, injected into the furnace with an air-blast just as oil is
used. The coal is thoroughly dried and ground very fine.
Its only drawback seems to be almost explosive combustibility,
rendering its storage unsafe. The temperature attainable by
this means seems to be almost equal to that with oil, and in
respect to cost and some other considerations it is more ad-
vantageous.

During the year a wonderful growth in the manufacture of
Portland cement has taken place in the United States, so that
within the coming decade we may reasonably expect to supply
all of the home consumption and probably a great part of that
used in other countries. The principal improvement in meth-
ods has been the general introduction of the automatic rotary
kiln or burning furnace, These consist of inclined steel cylin-
drical shells about 60 feet long, mounted on rolls and lined with
magnesia brick. The cement mixture is pumped with water
or fed dry by a screw into the upper end and falls out as
burned clinkers continuously at the lower end. The fuel
used is oil, gas, or powdered coal, the process is continuous
and requires a minimum of manual labor. The success of
this invention, which has been brought about commercially in
the United States first, has been so pronounced that American
experts have been called to the oldest and best cement-pro-
ducing districts in the world, to reconstruct their plants on
the new lines.

In the manufacture of sulphuric acid, 1899 has seen the suc-
cessful beginning of the greatest revolution since this acid be-
gan to be produced on a large scale, namely, the production
of sulphuric trioxide, SO,, by the contact power of finely-divided
platinum on a mixture of sulphurous oxide and air. This re-
action was long ago discovered by Winkler and utilized for
making dry sulphuric trioxide and fuming acid, but the heat
produced soon checked the reaction, and the converting power
of the platinum soon gave out. The experts of the Badische
Anilin and Soda Mfg. Co., a few 5^ears ago discovered the
cause of the latter trouble to be the presence of dust and for-
eign gases, principally arsenic and phosphorus compounds,
and much moisture. By using purified gas and providing a
way of escape for the excess of heat generated by the reac-
tion, the process became quantitative, even with dilute sul-
phurous anhydride and hence commercially possible for making
all kinds of sulphuric acid. Many German acid makers
are reported to be rapidly eliminating their lead chambers and
using platinized asbestos or pumice-stone instead. The new

Report. 527

method is especially economical for the strongest acids, the
stronger the acid to be made the greater the economy over the
niter method. Weaker acids, up to chamber acid strength,
are probably still made much more cheaply by present meth-
ods. The new process is best also for making the purer
grades, for, by using pure sulphurous gas, chemically pure
acid can be made as cheaply as any other.

The latest antagonist by which the old salt-cake and muriatic
acid soda and bleach industry has been assailed, namely, the
electrolytic process of chlorine and soda production, has, dur-
ing the past year, developed into such a giant that, with its
older competitor, the ammonia-soda process ever enlarging,
the death of the lycBlanc process cannot be postponed many
years. Only in Great Britain does the process, by virtue of
the retaining energy of immense capital invested, survive to
anj^ considerable extent. On the European continent ammo-
nia soda had practicall}' expelled it without the assistance of
electrolytic methods. In this country it never had a foothold.
In England it has survived mainly because of the profit on
the chlorine industries. Now, electrolytic methods have re-
moved this last prop, producing bleach as cheaply as the
value of the hydrochloric acid used in the older processes.
No competition is really ever likely to exist between the am-
monia soda and electrolytic processes, because the soda pro-
duced by electrolysis is of little worth compared with the value
of the halogen. The electrolytic production from salt of all
the bleach used would produce only an eighth of the soda re-
quired for the world's consumption. There is even some pos-
sibility that hydrochloric acid may be made eventually by
uniting electrolytic chlorine and hydrogen. The principal
electrolytic processes so far successfully installed are the
Kastner-Kellner mercury method with large plants at Niagara
Falls and in England, the Hargreaves-Bird process using an
asbestos diaphragm, with a considerable plant at Liverpool,
and the large works at Leopoldschall. The plant at Rumford
Falls, Maine, using platinum electrodes, went out of opera-
tion during the year. Probably the momentum of large capi-
tal invested in the chamber-acid plants and in the LeBlanc
soda process will maintain for both a more or less profitable
existence for a number of years to come, in spite of all com-
petition.

The great change in the chlorate industry has already been
referred to. Practically all that in use is now made by elec-
trolysis. There has been a marked decrease during the year
in American imports of chlorate, soda and caustic, due to the
installation of large ammonia-soda works at Syracuse, Detroit,

528 Rep07't.

and Bay Cit}^ and another large works is now under construc-
tion at Barberton.

The manufacture of calcium carbide has grown during the
year to immense proportions, but with a maintenance of
prices, showing a large increase in its use. In Germany
nearly all of the railwa}^ coaches are now lighted by a mix-
ture of one-third acetylene and two-thirds Pintsch gas, result-
ing in both an increase of light and decrease of cost.

Another product of the electrical arc furnace which has
been largely manufactured during the past year and has
found an even larger demand, is graphitized electrolytic car-
bons. It is found that when ordinary pressed carbons are
packed in charcoal and placed in the path of a large electrical
current so as to be intensely heated for a considerable time,
the carbon of which the}' are composed is practically con-
verted into graphite. Such graphitized carbons, owing to the
uniform texture which thej' are given, and to the higher power
to resist oxidation, are found to have two or three times the
life of ordinary carbons for all electrolytic purposes, and their
use is rapidly growing.

In the manufacture of wood spirits a greater purity of prod-
uct has been brought about by greater care in fractioning.
Also man}^ new externally heated retort plants are replacing
old kiln-furnaces with internal firing for making charcoal, and
greater econom}^ is being attained in acetate production.

In the way of rubber products, the new substitute, Reid's
"velvril" is claimed to have had a successful year's trial in
England, and to have gained a large use. Velvril is a drying
oil which has been nitrated, mixed by a common solvent with
nitrocellulose, and the solvent subsequently^ removed. Castor
oil is said to be used and, after nitration, contains 4-5 per
cent of nitrogen. This, with nitrocellulose, forms a clear,
homogeneous, rubber-like mass, its hardness being wholly
under control by var5nng the relative proportions of the two
ingredients, from a consistenc}' like vulcanite to that of the
softest rubber. The article to be made may be shaped from
the mixture while softened by a solvent, or formed into shape
by high pressure and heat somewhat above 100° C. In spite
of its nitrated character, it is not explosive, but burns slowly
and quietly. Numerous uses are claimed for the new com-
pound by its inventors, including insulating material, cloth-
ing, belting, varnish, paint, enameling of leather, cement for
wood, glass, metal, etc., hose and tubing, and even as a modi-
fier of the explosive rate and power of guncotton and nitro-
glycerin. If onl}^ a small proportion of these claims stand the
test of continued use, a most valuable discover}^ has been

Reviews. 529

made and a substance of the widest applicability and use
found at an exceedingly opportune time, because of the enor-
mously increased demand for rubber in so many industries.

Not even a few of the inventions and processes described
above were actually begun or perfected during 1899, but all
for the first time last year stood the test of continued practical
use. Inventions almost without number are recorded every
year, but it would take an omnipotent judge to select those
that are destined to work industrial revolutions, and their de-
scription or bare enumeration would be of little interest and
less value here. The record given has therefore been con-
fined to those inventions and changes which the year has re-
corded as of permanent value and which have proved them-
selves commercially successful.

ALBERT W. Smith.
Case School of Applied Science.

REVIEWS.

The Theory of Electrolytic Dissociation and Some of Its Ap-
plications. By Harry C. Jones. The Macmillan Co. 1900.

In preparing this little book the author has had particularly
those readers in mind who desire to keep in touch with the
recent progress of physical chemistry, but who have not
the time and opportunity to consult the original literature or
larger German treatises on the subject. Until the recent and
very timely appearance of Dr. Walker's excellent work on
physical chemistry, there has been, in fact, no English
source to which the reader could be unqualifiedly referred, so
that the present work will be welcome to a large circle of
readers. As the author states in his preface, an attempt is
made to answer the questions : ' ' What was physical chemis-
try before the theory of electrolytic dissociation arose ? How
did the theory arise ? Is it true ? What is its scientific use ?' '
and the chapters into which the book is divided correspond to
the divisions thus indicated.

Chapter I contains an outline of work done prior to 1885,
when modern physical chemistry may be said to have had its
beginning ; all work which in any way touches on the rela-
tions between properties of bodies and their composition and
their constitution as well as that on thermochemistry and elec-
trochemistry is here considered : and the characteristic fea-
ture of the "old physical chemistry" — namely, its empirical
inductive nature is pointed out. This chapter, which takes
up a quarter of the whole book might, in the opinion of the re-
viewer, have been considerably abbreviated to advantage.

The second chapter on the origin of the theory of electro-

530 Reviews.

Ij'tic dissociation is admirable and is thoroughly enjoyable
reading. The essential parts of Pfeffer's, Vau't Hoff's, and
Arrhenius' epoch-making papers are given in their authors'
own words, all being clearly knit together in historical
sequence. A feature of this chapter is the introduction of ex-
tracts from Van 't Hoff's Berlin lecture in 1S94 on " How the
Theorj' of Solutions Arose" which gives the reader a feeling
of almost personal acquaintance w'ith the working of this mas-
ter mind. Chapter III, "Evidence Bearing upon the Theory, ' '
is devoted to a discussion of the numerous physical and chem-
ical phenomena which have found a satisfactory explanation
in the light of the dissociation theory. The illustrations are
numerous and well chosen, but the general impression left on
one unacquainted with the history of the theory is that the
dissociation theory has been accepted almost without a ques-
tion and that it will ultimately take its place among the so-
called " laws of nature." This seems unfortunate to the re-
viewer, although himself a warm supporter of the theory ; for,
while it is unquestionably true that the h^-pothesis of Arrhe-
nius, and the theory since built upon it as a foundation, hasdone
more than any previous theory to explain the correlated phe-
nomena of physics and chemistrj^ yet it is equally true that
it still fails to account at all for some unquestionable facts
and has had, and still has, some weighty opponents. A short
chapter on the objections which have been raised to the theory
and the arguments with which they have, for the most part,
been satisfactoril}^ answered, would have added to the value
of the book and not left the reader with the impression that
the theory has attained its present position without a struggle.

The concluding chapter is devoted to applications of the
theory. The various methods of determining electrolytic dis-
sociation are considered, and also certain applications to bio-
logical and toxic problems. Nernst's theory of the voltaic
cell, liquid cells, gas batteries, etc., is gone into at considera-
ble length, this being of particular interest to the phj^sicist.
The reviewer would point out that the question of the true
seat of electromotive force in the voltaic cell was pretty defi-
nitely settled prior to the dissociation theory in an admirable
paper by Lodge, in 1885, although no satisfactory theory to
account for it was given until the appearance of Nernst's
paper.

The work before us is a welcome addition to our literature,
and will, no doubt, contribute its part in winning new disci-
ples to the present large (in this country at least) following
of the Van't Hoff-Ostwald- Arrhenius school.

H. M. Goodwin.

Reviews. 531

Traite Ele;mkntaire de Mecanique Chimique Fondee sur la
Thermodynamique. Par P. Duhem, Professeur de Physique Th^-
orique a La Faculte des Sciences de Bordeau. Tome IV, Les Me-
langes Doubles. Statique Chimique G^nerale des Systemes Hetero-
genes. Paris, Librairie Scientifique A. Hermann, pp. 381. 1899.

The appearance of the earlier volumes of Duhem's work has
already been noticed in this Journal (19. 621). The nature
of the fourth volume can best be seen from a brief account of
its contents. This volume contains two books, 8 and 9.
Book 8 deals with double mixtures and is divided into nine
chapters. Chapter I, General Theory of I^iquid Mixtures;
Chapter II, Theory of Distillation ; Chapter III, Critical Con-
ditions of a Mixture ; Chapter IV, lyiquefaction of a Gaseous
Mixture ; Chapter V, Liquid Double Mixtures ; Chapter VI,
Gaseous Solutions; Chapter VII, Mixtures of Volatile Liquids;
Chapter VIII, Dissociation ; and Chapter IX, Isomorphous
Mixtures. The amount of material treated in book 8 is very
great, indeed, and it will be noticed that it includes much that
is usually treated in works on physical chemistry under the
head of solutions.

Book 9, on Chemical Statics of Heterogeneous Systems,
deals with the general principles of statics at a given pressure,
general principles at a given volume, and general theorems of
univariant and bivariant systems.

The whole work is written from the mathematical and theo-
retical standpoint rather than from the experimental and,
therefore, appeals only to those who are well advanced in the
subjects treated. A larger number of references to the litera-
ture might have made the work a little more useful to the in-
vestigator. The book is very clear, and will doubtless prove
of great service in this important branch of science. H. c. j.

LE50NS DE CHiMiE Physique. Professees a L'UNrvERSiTE de Ber*
LIN. Par J. H. Van'T Hoff. Membre de L' Academic des Sciences
de Berlin. Professeur ordinaire a L'Universite et directeur de L'ln-
stitut de Physique de Charlottenbourg. Ouvrage traduit de I'alle-
mand par M. Carvisy, Professeur agreg^ au Lycee de Saint-Omer,
Deuxieme Partie. La Statique Chimique. Paris, Libraire Scienti-
• fique A. Hermann, pp. 162. 1899.

The translation of the second part of Van' t Hoff's book into
French has thus appeared shortly after the German edition.
This shows that the work of the great leader in modern phys-
ical chemistry is appreciated and valued in France as well as
in his adopted country — Germany. The appearance of the
first part of this book has already been noticed in this Jour-
nal (20, p, 610). The second part on chemical statics deals
with : I, Molecular Weight and Polymerism, including de-
termination of the molecular weights of rarefied gases, and de-
termination of molecular weights in dilute solutions ; II. Mo-

532 Errata.

lecular Structure (Isomerism, Tautomerism), and as subdi-
visions, determination of constitution, determination of con-
figuration (stereochemistry) and tautomerism ; III. Molecu-
lar Grouping (Polymorphism), comprising the laws which
govern the reciprocal transformation of polymorphous sub-
stances, and molecular grouping properly so-called.

As is well known this work is, in a certain sense, a repro-
duction of the course of lectures given by Van 't Hoff in the
University of Berlin on selected topics in physical chemistry.
As far as it goes it contains, of course, what is newest and
best in the subjects treated. It cannot, however, be regarded'
as a systematic and comprehensive text-book, covering the
whole field of modern physical chemistry, and it is not adapted
to the beginner in this branch of science. For those who are
well grounded in the fundamental principles of the subject,
this book is invaluable and needs no other recommendation
than the name of its author. h. c. j.

ERRATA.

w^age 296, line 17 from below, for " ammonia" read "am-
monia at — 38°."

L>Page 297, line 8 from above, for "water" read " water at
18°, " and for " ammonia" read " ammonia at — 38°."
,, Page 298, line 18 from below, for "a" read " «."
i,^ Page 299, lines 3 and 19 from above, for "a" read "or."
^^-Page 306, line 5 from above, insert "or" after " salt."
i^Page 306, line 15 from below, for "investigators" read
" investigations."

l^age 306, line 6 from below, for " 1856" read " 18.56."
• Page 307, line 12 from above, insert "coefficient" after
"temperature."

Page 452, line 7 from below, for " potassium chloride" read
" potassium bromide."

INDEX VOL. XXIII.

AUTHORS.

AREY, A. L,. Elementary chemistry (Review) 361

Atwater, M. D. See Wheeler, H. L.
BARNES, B. See Wheeler, H. L.
Beatty, L. O. See Kaslle, J. H.

Benedict, F. G. Absorption apparatus for elementary organic analysis 323

The elementary analj^sis of organic substances containing nitrogen... 334

Billz, H. Qualitative analyse unorganischer substanzen (Review) 275

Experimentelle Einfiihrung indie unorganische Chemie (Review) . 275
Brewer, C. E. See Orndorff, W. R.

Bucher,J. E. The action of ethyl iodide on tartaric ester and sodium ethylate 70
Byers, H. G. See Morse, H. N.
CAMERON, F. K. Estimation of alkali carbonates in the presence of bicar-

bonates 471'

de Chalmot, G. L.J. (Obituary notice) ~ 447

Chambers, V . J . s.miA Frazer , J . C. W. On a minimum in the molecular lower-
ing of the freezing-point of water, pro-
duced by certain acids and salts 512

" S&^ Jones, H. C.

Charabot, E. Les parfums artificiels (Review) 275

Chaitaway, F. D., and Orton, K. J. P. Preparation and properties of the so-
called " nitrogen iodide " 363

" " " Stevens, H. P. The action of reducing agents upon ni-
trogen iodide 369

Chikashige. M. See Kuhara, M.
Conn, W. T. Se& Michael, A.

Cooper, H. C. Stereoisomers and racemic compounds 255

Crane, F. D. A contribution to the knowledge of tellurium 408

Curtiss, R. S. On the action of nitrous acid on ethyl anilinomalonate 509

DUHEM, P. Traits El^mentaire de M^canique Chimique Fondle sur la Ther-

modynamique (Review) 531

EDGERLY, D. W. SeeiVorrij,/. i^

Eliot and Storer. Qualitative chemical analysis (Review) 273

Elliott, A . H., and Ferguson, G. A . Qualitative chemical analysis (Review) . . . 451
FAY, H. See Norris, J. F.

Franklin, E. C, and Kraus, C. A. The electrical conductivity of liquid ammo-
nia solutions 277

Fraps, G. S. The supposed isomeric potassium sodium sulphites 202

Frazer,J. C. W. See Chambers, V.J.
Fuller, R. W. See Jackson, C. L.
GAZZOLO, F. H. See Jackson, C. L.

Gomberg, M. Diazocaffeine 50

Green. J. R. The soluble ferments and fermentation (Review) 85

HIGBEE, H. H. The double halides of antimony with aniline and the tolui-

dines 150

Hillyer, H. W. Action of picryl chloride on pyrocatechin in presence of al-
kalies 125

Hollis, F. S. The synthetical chloride of paranitroorthosulphobenzoic acid... 233
JACKSON, C. L. and Fuller, R. W. Note on the constitution of diparabroraben-

zylcyanamide 494

" and Gazzolo, F. H. On certain colored substances derived

from nitro compounds 376

534 Index.

Jones, H. C. The theory of electrolytic dissociation and some of its applica-
tions (Review) 529

" ^wA Chambets, V.J. On some abnormal freezing-point lowerings

produced by chlorides and bromides of the

alkaline earths 89

" ^r\A Smith, A. IV. The solution-tension of zinc in ethyl alcohol.. 397
KASTLE, J. H. On the effect of very low temperatures on the color of com-
pounds of bromine and iodine 500

" and Beatty, L. O. On the supposed allotropism of phosphorus

pentabromide 505

Kraus, C. A. See Franklin, E. C.

Kuhara, M., and Chikashige, M. A method for the determination of the melt-
ing-point 230

LANDOI<T, H. Optical activity and chemical composition (Review) 271

Lassar-Cohn. Einfiihrung in die Chemie in leichtfasslicher Form (Review).. 88

Lehfeldi, R. A. A text-book of physical chemistry (Review) 270

MAQUENNE. I/- Les sucres et leurs principaux d6riv6s (Review) 267

McCoy, H. N. An apparatus for determining molecular weights by the boil-
ing-point method 353

Meyer, H. Determination of radicals in carbon compounds (Review) 451

Meyer, O. E. The kinetic theory of gases (Review) 272

Michael, A., a.116. Conn. W. T. On chlorine heptoxide 444

Mo?nmers, R. See Norris,J. F.

Morse, H. N., and Byers, H. G. On the cause of the evolution of oxygen when
oxidizable gases are absorbed by permanganic

acid 313

Morse, H. N. , and Olseyi, J. C. Permanganic acid by electrolysis 431

Morton, D. A. See Orndorff, W. R.

NAGEL, I- On the rancidity of fats 173

Nernst,W. Theoretische Chemie (Review) 179

NorriSfJ. F. and Fay, H. The reduction of selenium dioxide by sodium thio-

sulphate 119

" " " " and Edgerly, D. W. The preparation of pure tellu-
rium 105

" " and Mommers.R. On the isomorphism of selenium and tellurium 486

Noyes, W. A. Camphoric acid 128

OIvSEN, J. C. See Morse, H. N.

Orndorff, W. R. and Brewer, C. E. The constitution of gallein and coerulein.. 425

" zjid Morton, D. A. Anethol and its isomers 181

Orton, K.J. P. See Chatiaway, F. D.

RAMMELSBERG, CARI, FRIEDRICH. (Obituary notice) 261

Ransom, J. H. On the molecular rearrangement of o-aminophenylethyl car-
bonate to o-oxyphenylurethane I

von Richter. V. Organic chemistry, translation (Rexdew) 362

SMITH, A. W. %^^ Jones, H. C.
Stevens, H. P. See Chattaway, F. D.

Stieglitz,J. Notes on lecture experiments to illustrate equilibrium and disso-
ciation 404

THORP, F. H. Outlines of industrial chemistry (Review) 268

Thresh, J. C. Water and water supplies (Review) 268

Tiemann,J. C. W. F. (Obituary notice) 178

Tillman, S. E. Descriptive general chemistry (Review) 274

Tilden, W. A. A short history of the progress of scientific chemistry in our

own times (Review) 271

Tingle, J. B., and Tingle, A. Condensation compounds of amines and cam-

phoroxalic acid 214

Titigle, A. See Tingle, J. B.

Index. 535

VAN 'T HOFF, J. H. Lecons de chimie physique (Review) 531

WADDELL, J. The arithmetic of chemistry (RexHew) 275

Walker, J. Introduction to physical chemistry (Review) 269

IVheeUr, H. L. On the rearrangement of imidoesters 135

" Researches on the sodium salts of the amides 453

" and Atwaier, M. D. Experiments with furimidomethyl ester,

^-tolenylimidomethyl ester and /3-naphthyl-

imidoethyl ester 145

" and Barnes, B. Experiments with silver succinimide and ben-

zoylbenziniidoethyl ester 14S

SUBJECTS.

ABSORPTION apparatus for elementarj' organic analysis. F. G. Benedict.... 323
Description of apparatus and method of use.

Alkaline earths, on some abnormal freezing-point lowerings produced by

chlorides and bromides of the. H. C.Jones anA Chambers, V.J 89

Amides, researches on the sodium salts of the. H. L. Wheeler 453

Relative ease of formation of salts with formanilide, acetanilide, pro-
pionanilide, benzaraide, methylbenzamide, ethylbenzamide, benzoyl-
benzamide, oxindol, phthali:nidine, phenyloxamide, orthoformtoluide,
orthotoluamide, a-forranaphthalide, a-naphthamide, 2,4,6-trimethyl-
formanilide, 2,4,6-trimethylbenzamide, 2,4,6-tribrombenzamide. 2,4,6-
tribrom-N-dimethylbenzamide 2,4,6-tribrombenzoyl chloride and potas-
sium hydrate, 2,4,6-methyltribronibenzoate and potassium hydrate,
thioacetanilide sodium hydrate.

o-Aminophenylethj-1 carbonate to o-oxyphenylurethane, on molecular rear-
rangement of. J. H. Ransom I

Theoretical; reduction of o-nitrophenylethylcarbonate, 14; prep, of
benzoyloxyphenylurethane and benzoyl-o-aminophenol, 17 ; action of
ethylchlorformate on benzoyl-o-aminophenol, 17; dry distillation of
benzoyloxyphenylurethane, 19 ; benzoylcarbonyl-o-aminophenol, 20 ;
;«-nitrobenzoyloxyphenylurethane, 22 ; ;«-nitrobenzoylcarbonj'lamino-
phenol, 24; wz-nitrobeDzenyl-<9-aminophenol, 24; ;«-nitrobenzoyl-o-ami-
nophenol, 26 ; action of ethylchlorformate on »2-nitrobenzoyl-«-amino-
phenol, 27 ; wi-nitrobenzoyl-<3-aminophenolbenzoate, 28 ; benzoyl-<5-ami-
nophenol->/2-nitrobenzoate, 29 ; carbethoxyaminophenol pheuylcarbam-
ate, 31; action of chlorformate on oxydiphenylurea, 32 ; acyl deriva-
tives of methyl-o-aminophenol, 33 ; carbonylmethylaminophenol, 33;
prep, of o-methylaminophenol, 34; benzoylmethyl-o-aminophenol, 34;
o-oxyphenylmethylurethane and benzoyl derivative, 35 ; ;«-nitroben-
zoj'lmethyl-€>-aminophenol, 36 ; methylation of oxyphenylurethane, 38 ;
o-methoxyphenylurethane, 39 ; o-:nethoxybromphenylethylurethane,
39; o-anisidine phenylurea, 40 ; methylation of o-oxyphenylurethane
with diazomethane, 41 ; o-aminophenylethyl carbonate, 43 ; action of
HCl on ethoxymethenyl-o-aminophenol, 46 ; /-nitrophenylcarbonate,
47 ; synthesis of ^-nitrophenylethylcarbonate, 48 ; /i-aminophenylethyl
carbonate, 48 ; /-ureidophenylethyl carbonate, 49.

Anethol and its isomers. W. R. Orndorff and D. A . Morton 181

Physical props., iSi ; action of iodine and formation of anisoin, 183 ; of
HCl and formation of anethol hydrochloride, 183 ; of picric acid and
formation of picrate, 184; of Br and formation of dibromide, 1S5 ; of
N5O3 and formation of nitrosite, 187 : of NOCl and formation of nitroso-
chloride, 1S7 ; fluid metanethol, 188; alcohol addition-product of an-
ethol, 191 ; anethol hydrobromide, 194 ; action of H3SO4, 194; anethol di-
hydride, 196; anisoin, 197; methyl ether of paracresol, 198.

Anethol dibromide. W. R. Orndorff and D. A. Morton 185

536 Index.

Anethol dihydride (Parapropyl anisol), C]oHi40. W. R. Orndorff and D. A.

Morton 196

Anethol hydrobromide, CjoHijOBr. W. R. Orndorff" and £>. A. Morton 194

Anethol hydrochloride, CjoHijOCl. IV. R. Orndorff' and D. A . Morton 184

Antimony, the double halides of, with aniline and the toluidines. H. H.Higbee 150
Methods of prep.; discussion of possible salts and crystallographic
study of compounds obtained.

Arithmetic of chemistry, the. J. JVaddell (Review) 275

BICARBONATICS, estimation of alkali carbonates in the presence of . F. JiT.

Cameron 471

Bromine and iodine, on the effect of very low temperatures on the color of

compounds of. J. H. Kastle 500

CA.MPHORIC ACID. W. A. Noyes 128

Synthesis of 2,33-trimethylcyclopentanone, 129 ; 2,33-tetraniethylhex-
anoic 1,2',6-acid, 131 ; dimethylcyancarboxethylcyclopentanone, 135.

Camphoroxalic acid, condensation compounds of amines and. J. B. Tingle and

A . Tingle 214

Theoretical, 214 ; action of camphoroxalic acid on a-naphthylamine,
222; on /3-naphthylamine, 222; on orthophenylenediamine, 223; on
semicarbazide, 224 ; on aniline, 225 ; action of ethylic camphoroxalate
on aniline, 226; on ^-naphthylamine, 227; on semicarbazide, 227; on
orthophenylenediamine, 228; experiments with phenylcamphoformene-
amine, 229.

Carbonates in the presence of bicarbonates, estimation of alkali. F. K. Cam-
eron 471

Determination by titration with a standard solution of acid sodium or
potassium sulphate, using phenol phthalein as an indicator.

Chimie physique, lecons de. J. H. VanHHoff (Review) 531

Chlorine heptoxide. A. Michael and IV. T. Conn 444

Preparation from perchloric acid.

Colored substances derived from nitre compounds. C.L.Jackson and F.H.

Gazzolo 376

Preparation of picryl chloride, 384 ; action of sodic acetacetic ester
with trinitranisol, 384 ; of malonic ester with trinitranisol and trinitro-
benzol, 388 ; action of bromine on latter compound, 389 ; action of acet-
acetic ester on trinitrobenzol, 390 ; trisodic amylate addition-product
of trinitrobenzol, 390; experiments on the replacement of the allyl
radical in the colored compounds, 394.

DIAZOCAFFEINE. M. Gomberg 50

Prep, and props, of diazocaffeine, 58; cafifeine-^-azophenol, 59; caf-
eine-/-azodiraethylaniline, 60; reduction with stannous chloride, 61 ;
prep, and props, of caffeineazo-2,4-diamido benzene, 62 ; caffeineazo-^-
naphthol, 63 ; reactions with acetoacetic acid, 64 ; propylacetoacetic
acid, 65; benzylacetoacetic acid, 67 ; nitroethane, 67; nitropropane, 69.

Diparabrombenzylcyanamide. C. L.Jackson and R. IV. Fuller 494

Prep, and props., 497 ; decomposition with sulphuric acid to form di-
parabrombenzylamine, 499.

EINFUHRUNG indieChemieinleichtfasslicherPorm Lassar-Cohn {Revievf) 88

Electrical conductivity of liquid ammonia solutions. E. C.Franklin and C. A.

Kraiis 277

Electrolytic dissociation, the theory of, and some of its applications. H. C.

Jones (Review) 529

Elementary chemistry. A. L. Arey (Review) 361

Equilibrium and dissociation, notes on lecture experiments to illustrate. J.

Stieglitz 404

Experiments with PBrg and PBr, ; PClsBr, and PCI, ; NH4OH and
ammonium salts.

Index, 537

Sthyl anilinomalonate, on the action of nitrous acid on. R. C. Curitss 509

Prep, and props, of compounds.
, Ethylic /3-naphthylcamphoformeneamincarboxylate, Cj4Hj,OjN, J. B. Tingle

and A . Tingle 327

Ethylic phenylcamphoformeneaminecarboxylate, CjoHjjOsN. J. B. Tingle

and ^ . Tingle 226

Ethylic semicarbazylcamphoformenecarboiylate, C,5H,304Ns. J. B. Tingle

and^. Tingle 228

Ethyl iodide, the action of, on tartaric ester and sodium ethylate. J. E. Bucher 70
Conditions of reactions and formation of salts.

FATS, on the rancidity of. I. Nagel 173

Methods of prevention.

Ferments and fermentation, the soluble. J. R. Green (Review) 86

Freezing-point lowerings, on some abnormal, produced by chlorides and bro-
mides of the alkaline earths. //^. C.Jones and V.J. Chambers 89

Results with Ca, Ba, Sr, Mg, and Cd chlorides and bromides.
Freezing-point of water, on a minimum in the taolecular lowering of the, pro-
duced by certain acids and salts. V.J. Chambers andy. C. W. Frazer.. 512
Action in case of hydrochloric acid, phosphoric acid, sodium acetate,
zinc chloride, strontium iodide, cadmium iodide, and copper sulphate.
Furimidomethyl ester, />-tolenylimidometh3'l ester, and )3-naphthylimidoethyl

ester. H. L. IV heeler and M. D. Atwaler 145

Prep, of ester and action with methyl iodide, 145 ; prep, of /-tolenylimi-
domethyl ester and action with methyl iodide and alcohol, prep, of
^-naphthylimidoethylester and action with ethyl iodide.

GADOLINIUM (Note) 447

Gallein and coerulein, the constitution of. W. R. Orndorff" and C. E. Brewer.. 425

General chemistry. 5". E. Tillman (Review) 274

IMIDOESTERS. on the rearrangement of . H. L. Wheeler 135

Action of benzimidomethyl ester and methyl iodide, 138 ; of ethyl ester
and ethyl iodide, 140: prep, of diethylbenzamide, 140 : action of benz-
imidoisobutyl ester and methyl iodide, 141 ; same with isobutyl iodide
142 ; prep, of isobutyl benzamide, 142 ; action of ethyl ester and iso-
butyl iodide, 142.

Industrial chemistry, outlines of. F. H. Thorp (Review) 268

Inorganic ferments. (Note) 449

KINETIC theory of gases, the. O. E. Meyer (Review) 272

LIQUID ammonia solutions, the electrical conductivity of. E. C. Franklin and

C. A. Kraus 277

Description of apparatus and value of about 25 substances with discus-
sion of results.
Low temperatures on the color of compounds of bromine and iodine, on the

effect of very. J. H. Kastle 500

Color becomes lighter when substance is cooled.
MECANIQUE CHIMIQUE, Traite Elementaire de, Fondee sur la Thermody-

namique. P. Duhem (Review) 531

MELTING-POINT, a method for the determination of the. M. Kuhara and M.

Chikashige 230

Metanethol. W. R. Orndorff and. D. A. Morton 188

Molecular weights by the boiling-point method, an apparatus for determin-
ing. H. N. McCoy 353

A modification of the method of Walker and Lumsden.

Monobromanethol dibromide. W. R. Orndorff and D. A . Morton 185

o-NAPHTHYLCAMPHOFORMENEAMINECARBOXYLIC acid, C,6H„0,N.

J. B. Tingle and A. Tingle 222

P-Naphthylcamphofonneneaminecarboxylic acid, CjjHjjOaN. /. B. Tingle

and A. Tingle 223

538

Index.

\

Nitrogen compounds, asymmetric optically active. (Note) td^

Nitrogen iodide, action of reducing agents upon. F. D. Chattaway sm6. H . P.

Stevens 369

Action of Na,SOj, HjSOi.As^Sa, Sb^O,, SnCl,, and HjS with formation
of HI.
"Nitrogen iodide," prep, and props, of the so-called. F. D. Chattaway and K.

J.P.Orion 363

Nitrogen, the elementary analysis of organic substances containing. F. G.

Benedict 334

Notes.

Asymmetric optically active nitrogen compounds 265

Gadolinium 447

Improvements in the manufacture of sulphuric acid 83

On inorganic ferments 449

Polonium and radium 262

The vyax of the .ffaczV/ariaceae and its relation to petroleum 176

OBITUARY NOTICES.

de Chalmot, G. L. J 447

Rammelsberg, Carl Friedrich 261

Tiemann, J. C. W. F 17S

Optical activity and chemical composition. H. Landolt (Review) 271

Organic analysis, absorption apparatus for elementary. F. G. Benedict 323

Organic substances containing nitrogen, the elementary analysis of. F. G.

Benedict 334

Organic chemistry. K. fon .^zcAier (translation) (Review) 362

Oxygen, on the causes of the evolution of, whenoxidizable gases are absorbed

by permanganic acid. H. A'. Morse and H. G. Byers 313

PARACRESOL, methyl ether of, CgHioO. IV. R. Orndorff &u6. D. A. Morton.. 198
Paranitroorthobenzoylbenzenesulphonic acid, lactim of, CijHsOiNjS. F. S.

Holhs 252

Paranitroorthobeuzoylbenzenesulphone chloride, CjjHgOjNClS. F. S. Hollis. 242

Paranitroorthosulphobenzoic acid, chloride of, C7H3O5NCIJ. F. S. Hollis 235

Paranitroorthosulphobeuzoic acid, the symmetrical chloride of. F. S. Hollis. 233
Action of PCle on the acid potassium salt. 234; prep, of chlorides, 235 ;
action of benzene and aluminium chloride ou the chlorides, 239 ; action
of HCl on the chloride, 243 ; salts of the acid, 244 ; action of HjSOi on
the chloride, 245 ; of water, 246 ; of alcohol, 246; salts of paranitroor-
thobenzoylbenzenesulphonic acid, 24S ; action of PCI5 on the sodium
salt, 259 ; action of cone. NH3 on the chloride and lactim, 251 ; of HCl
on the lactim, 253.

Parfums artificiels, les. E. Charabot (Review) 275

Permanganic acid by electrolysis. H. N. Morse and J. C- Olsen 431

Prep, of pure acid and determination of conductivity.

Petroleum, wax of .fiaczV/arzaceae and its relation to. (Note) 176

Phosphorus pentabromide, on the supposed allotropism oi J. H. Kastle and L.

O. Beatty 505

Probable presence of phosphorus heptabromide.

Physical chemistry, a text-book of. R. A . Lehfeldt (Review) 270

Physical chemistry, introduction to. J. IValker {Review) 269

Picryl chloride, action of, on pyrocatechin in presence of alkalies. H. IV.

Hillyer 125

Picryl chloride, preparation of. C. L. Jackson and F. H. Gazzolo 384

Polonium and radium. (Note) 262

Potassium sodium sulphites, the supposed isomeric. G. S. Fraps 302

Historical r6sum6 and methods of work.

Index. 539

Pyrocatechin in presence of alkalies, action of picryl chloride on. H. W.

Hillyer 125

Formation of a dinitrophenoxazone.

QUALITATIVE chemical analysis. Eliot sMd. Storer (Review) 273

Qualitative chemical analysis. Elliott and Ferguson (Review) 451

RADICALS in carbon compounds, determination of. H. Tl/e^^r (Review) 451

Radium. See polonium.

Reducing agent, action of, on nitrogen iodide. F. D. Chaltaway and H. P.

Stevens 369

Report.

The year's advance in technical chemistry 520

Reviews.

Arithmetic of chemistry, the. J. Waddell 275

Determination of radicals in carbon compounds. H. Meyer 451

Einfiihrung in die Chemie in leichtfasslicher Form. Lassar-Cohn. ... 88

Elementary chemistry. A. L. Arey 361

General chemistry. S. E. Tilhnan 274

Industrial chemistry, outlines of. E. H. Thorp 268

Kinetic theory of gases, the. O. E. Meyer 272

Lecons de chimie physique. J. H. VanH Hoff. 531

Optical activity and chemical composition. H. Landolt 271

Organic chemistry (Trans.). V.von Richter 362

Parfums artifi'ciels, les. E. Charabot 275

Physical chemistry, a text-book of. R. A. Lehfeldt 270

Physical chemistry, introduction to. J. Walker 269

Qualitative chemical analysis. Eliot and Storer 273

Qualitative chemical analysis. Elliott and Ferguson 451

Scientific chemistry in our own times, a short history of the progress

of. W. A . Tilden 271

Sucres et leurs principaux d6riv6s, les. L. Maquenne 267

Theoretische Chemie. W.Nernst 179

The soluble ferments and fermentation. J. Reynolds Green 85

The theory of electrolytic dissociation and some of its applications.

H. C. Jones 529

Traits 616mentaire de m^canique chimique fondle sur la thermody-

namique. P. Duhem 531

Unorganische Chemie, e.xperimentelle Einfiihrung in die. H. Biltz... 275

Unorganischer Substanzen, qualitative analyse. H. Biltz 275

Water and water supplies. J. C. Thresh 268

SCIENTIFIC chemistry in our own times, a short history of the progress of.

W. A. Tilden (Review) 271

Selenium and tellurium, on the isomorphism of. J. F. Norris and R. Moiyimers 486
Study of mixed salts ; double salts of tellurium with the methylamines.

Selenium dioxide, the reduction of, by sodium thiosulphate. J. F. Norris and

H. Fay itg

Conditions necessary for reaction.

Silver succiuimide and benzoylbenziraidoethyl ester, experiments with. H. L.

Wheeler 2m6l. B. Barnes 148

Form of N-methylsuccinimide from silver salt and methyl iodide, 148;
action of benzoylbenzimido ester and ethyl iodide, 149.

Solution-tension of zinc in ethyl alcohol. H. C. Jozies and A . W. Smith 397

Stereoisomers and racemic compounds, /f. C. Cooper 255

(a). Solubility of stereoisomers in an indifferent active solvent, 255 :
sodium hydrotartrates and sodium ammonium tartrates in dex-
trose solution ; (b). Properties of inactive mixtures, 259 : melting-
point and solubility ; (c). Partial racemism, 260.

Sucres et leurs principaux d6riv6s, les. L. Maquenne (Review) 267

Sulphuric acid, improvements in the manufacture of. (Note) 83

540 Index.

TECHNIC Alv CHEMISTRY, the year's advance in (Report) 520

Tellurium, a contribution to the knowledge of. F. D. Crane 408

Methods used to isolate and purify tellurium ; analysis and separation
of tellurium from selenium ; yellow form of the dioxide and decompo-
sition of the tetrachloride.
Tellurium, on the isomorphism of selenium and. J. F. Norris and R. Mommers 486
Tellurium, the preparation of pure. J. F. Norris, H. Fay and D. W. Edgerly. . 105
Prep, by decomposing the basic nitrate ; purification by fractional
crystallization.

Theoretische Chemie. W. Nernst {^&vmvi) 179

UNORGANISCHE Chemie, experimentelle Einfiihrung in die. H. Biltz

(Review) 275

XT norganischer Substanzen, qualitative analyse. H. Biliz (Keview) . . , 275

WATER and water supplies. J. C. Thresh (Review) 268

ZINC in ethyl alcohol, the solution-tension of. H. C. Jones and A . IV. Smith. 397

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