(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "A text-book of organic chemistry"

Google 



This is a digital copy of a book tliat was preserved for generations on library shelves before it was carefully scanned by Google as part of a project 
to make the world's books discoverable online. 

It has survived long enough for the copyright to expire and the book to enter the public doinain. A public domain book is one that was never subject 
to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vaiy country to counti^y. Public domain books 
are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover. 

Marks, notations and other marginalia present in the original volume will appear in this file - a reminder of this book's long journey from the 
publisher to a library and finally to you. 

Usage guidelines 

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the 
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to 
prevent abuse by commercial parties, including placing technical restrictions on automated quen'ing. 

We also ask that you: 

+ Moke non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for 
personal, non-cojnjnercial purposes. 

+ Refrain from aulomated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine 
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the 
use of public domain materials for these purposes and may be able to help. 

+ Maintain attribution The Google "watermark" you see on each file is essential for informing people about this project and helping them find 
additional materials through Google Book Search. Please do not remove it. 

+ Keep it legal Whatever your use. remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just 
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other 
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of 
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner 
anywhere in the world. Copyright infringement liability can be quite severe. 

About Google Book Search 

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers 
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web 



al |http : //books .google . com/ 



WORKS OF PROF. A. F. HOLLEHAN 

FUBtlSHED BY 

JOHN WILEY & SONS. 

A Text-book el iBOTfank CbMUlstO'. 

Ety Dr. A, F. HoLLSHAH, Profe«ioT Ordiuariiu in (he 
Unlvenlty of Croniagcn, Nelherlandt. Rendered into 
English by HKKUnN C. CaorsK, Ph.D., InitnKtor in Syr- 
acuse University, with the ca-operadon o( the author. 8vo, 
viii + 4jS pp., 84 figures. Cloth, fi.jo. 

A Tast-b«ok of Organic Cbcmlrtry. 

Rendered into English from the Second Dutch Edition by 
A. Jahiisoh Walker, Ph.D. (Keldelbeix), B.A, Head 
of Department of Chemistry, Municipal Technical College, 
Derby, Eng., assisted by Owen E. Murr, Ph.D. (Kei- 
' delbeix). Demonstrator ofChemtslrr, MunicCpsl Technical 
College, Derby, Eng , with the co-opeiation of the author. 
Bvo, avii 'f. 355 pages. 73 figures. Cloth, $9.50. 

A companioD volume lo the preceding, and lonning with 
It a comprehensive treatise on pure Chemistry. 



A TEXT-BOOK 



ov 



ORGANIC CHEMISTRY. 



' BT 

Dr. A. F. HOLLEMAN, 

Frofeuor Ordinariui in the UaiverMg of Oroningen, A'etherUmda. 



TRAKSLATSO FROlf TBB BSCOHD DUTCH BDrTtOS BT 

A. JAMIESON WALKER, Ph.D. (Heidelberg), B.A., 
Bead of the DepartmetU ofChtmtUtry, Municipal Technical OiBege, Derby, England. 

ABBISTED BT 

OWEN E. MOTT, Ph.D. (Heidelberg), 
Dtmanttrator of GKemuitry, ManMpal Technical College, Derby, England. 

WITH THE CO-OPEBATION OF THE AUTHOR. 



FTBST EDITION. 
FIEST THOUSAND. 



NEW YORK : 

JOHN WILEY ft SONS. 

London: CHAPMAN ft HALL, LrurrED, 

1903. 



Oopyrtibt, 1MB, 

BI 

A. JABUESON WALKGS. 
(£Mt«r«d at SloHontn' BaU.) 



■osnr DKDMiioin), ranmtB, xkw tork. 



AUTHOR'S PREFACE. 



Most of the short text-books of Organic Chemistry contain a 
great number of iaolat«d facts; the number of coropounda de- 
scribeU in them is so considerable as to confuse the begUmer. 
Moreover, the theoretical grounds on which this division of the 
scicace is based are often k«pt in the baokgroui^; for example, the 
ppoofn given of the constitutional formula frJ^ently leavp much 
to be desired. However useful these books may be for reference, 
they are often ill-suited for text-books, as luany atudents have 
Ii'anicd from their owti experience. 

Ill this book I have endeavoured to keep the number of unron- 
nectcd (acts within as narrow limits as possible, aad to give promi- 
nence to the theory undc-riying the subject. For this reason, * 
pmiif of the sLructiuT! uf most of the compounds iK given. This 
wa» not possible for tlie higtiex substitution-prochicts of the aromatic 
si-rUis, so tliat the methods of orientation employwl in it are de- 
scribed in a simrial chapter. 

Physico-chemical theories, suoh as the Uws of equilibrium, 
ionization, and others, are becoming more and more prominent in 
organic chemistry. 1 have attemptfld in many instances to show 
how useful \hey are in this branch of the ncience. Such importaat 
technical processes as the manufacture of alcohol, cane-sugar, etc., 
are also incluiled. The book is essentially a text-book, and makes 
no claim to be a "Bcilatcin" in a very compressed fonn. 

] am deeply indebted to Dr. A. J.^miison Walker for the excel- 
lent way iu which he has carrierf out the difficult lank of translating 
tliis book from the original .second Dutch edition into Knglish. 
Lastly, it may be mentioned that it han altui been translated into 
German, the scccmd edition having just appeared, and that aa 
Italian edition is in preparation. 

A. F. Hdlleiuak, 

QaoNiMOKil, NxTaRHLAKiM, Noveoiber, 1902. 

IU 



TRANSLATOR'S PREFACE. 



The cordial reception met with by Professor Hollbman's 
"Leerboek der Organische Chemie" in HoUand, as well as by 
Dr. Hof's translation in Germany, makes it cfffiirable that English- 
speaking students of chemistiy should share in the advantages 
derived from its publication by their fellow-students on the Con- 
tinent of Europe. 

This tt-anslation is from the second Dutch edition, published 
last year, and has been revised and added to by Professor Holle- 
MAN and myself bo as to make it as up-to-date as possible. An 
Italian translation of this English edition is now in preparation. 
The " Inorganic Chemistry " referred to in the text is Dr. Cooper's 
translation of Professor Holleman's "Leerboek der Anorganische 
Chemie," pubUshed last April by Messrs. John Wiley & Sons. 

I have to express my thanks to Professor Holleman for the 
great care bestowed by him on the work of revision; to Dr. Owen 
E. MoTT. for his valuable assistance ; to Professor Senier of Queen's 
College, Galway, for reading the proof and making many important 
suggestions; to Dr. John E. Mackenzie of the Birkbeck Institution, 
London, for reading part of the proof; to Dr. Hermon C. Cooi-eb 
of Syracuse University for the note regarding the law regulating 
the sale of alcohol in the United States; and to Messrs. John 
Wilet & Sons for the excellent way in which they have prepared 
the book for publication. 

' A. Jamisson Walker, 

Debbt, Enqland, December, 1902. 

r 



CONTENTS. 

Light figuiM refer to pages; old-€tyle Sgures to peragT^>hs. 

INTRODUCTION (i-aS) 1 

IJsvKtopMiMT OF Organic Chemistrt (i-a) 1 

QrAUTATIVE ANALTSIB (3-5) 3 

QcANTiTATivH Analtsis (6-g) 5 

I>£TERMINATION OT MOLECULAR WEIGHT (IO-I5) , 12 

Vapour density method, 13. Lowering of the freeting-point and 
Raising of the boiling-point methods, 16. 

The Element Cabbok (i6) 21 

Valency (17) 23 

Laboratort Mcthods (18-27) 24 

Heating substances together, 24. Distillation, 25 Steam distil- 
lation, 28. Separation of two immiscible liquids, 30. Separa- 
tion of solids and liquids, 31. Separation of solids from one an- 
other, 32. Determination of melting-points, 32. Determination 
of boiling-points, 33. Detennination of specific gravity, 33. Ro- 
tation of the plane of polarization, 33. 
Classification of Oeoantc Chsuistry (aS) 35 

FIRST PART. 
THE FATTY COMPOUNDS (29-358) 36 

Sattratkd Hydrocarbons (39-43) 36 

Methane, 36. Homologues of methane, 38 Nomenclature, 39. 
Occurrence in nature, 39. Homologous neries. 41. Isomerism 
and structure, 42. Carbon chains, 46. Law of the even num- 
bers of atoms, 47. Number of possible isomers, 47. Physical 
properties of isomeric compounds, 48. 

Alcohols, C,H,„ + ,0 (43-55) 49 

Methods of formation and constitution, 49. Nomenclature and iso- 
merism, 51. General properties, 52. Methyl alcohol, 53. Ethyl 
alcohol, 53. Propyl alcohols, S7. Butyl alcohob, 59. Amyl 
alcohola, 60. Van 't Hoff's theory of stereotsomerism, 62. 
Higher alcohols, 66. Alcoholates or metallic alkoxides, 66. 

Til 



TiU 



CONTENTS, 



ALKTt. Halidm, Bams, juni Brana Csfl-ti4) 67 

Alkyl halidM, 68. Eaton of othir mineral aeida, 71. SaponiAca^ 
lion, 72. Rtlivrs, 72. Diotliyl vlhcr, 73. Uoinolr^ucs of di- 
elhyl ellier. 75. 

AutVL-aAUicLGM L[MKr.» ■m Sri-Mim (65-*8) 77 

Mrrcupttin5, 78. Thi«»-tlifni, 70. t^tilphcuii^ itridB, 78. 

ALKVt^IIADIPLEB LiXKBD TO NlTKOGES (*9-77) M 

Amirtct ($9-74) SI 

Nomenclnturo and uomprism, 83. Methods of formatioii, ti2. 
I'ropiTlli's, SI. I»dlvidiial ine!reib«f!i, 85. 
tfitn-wmjiautida (75-7T)... 8S 

Al.KYI^KAI>ICLXf I.I.VKKU TO OTRKIl KlUIKNT* (TS-Si) 92 

.Ukjjt-mdifUi UnkeH to flrmenlt of Iht fiilrojftn group (7S-B0) 02 

Pboaphince, 92. Arsinrs, 03. Slibitirai, IM. Bismutliiaca, M. 

Alkijl-raitidis linktit to thr rlttnent* of tlu tarbon group lit) M 

Alkyl-radifU» Urtkcd to ttutaU (81) Qfi 

NmULSS ANU InOMTHIU^ (Sj-Ss) ..j . . . . . 07 

iBonitriloa or corbvlamines. 08 Nilriles, 09. 

AciM, CHjbO, (86-ii4) 101 

Formii; arid, 104 Acetic arid, 10(1 Butyric acids, 10&. Higher 

(nliy Btids, 109. Sr.inp*, 110 KWlrttljIic rliwwuitioii, HI. 

DUHIVATIVKA (IK THB FaTTY AcIIM OBTA]>fEO BY MoDIFTINO THE CaK- 

Boxrixmoup (os-ios) 1 U 

Aci<f ehl^tde* (95) 1 H 

vicuf atihsdridet (g6) IIS 

A'jH*r« (97-IC3) 115 

Foniialiou of wtcra, 117- EslerifiCAticn of prLin»ry, aecoud- 
ary, itnd icrtinry otcoholit, 121. 

Thta^eutM. K -Oft SH "<io3) 121 

Add amidn ( 104^ 121 

AmuiiKhlnridnt. fmino-^thera. Amuitnet, Amidvxima, Acid hydros 

«d« and Aftd ntiiien (105J 133 

ALDBUTDEtt AN1> KK1t)Nt:n ( lod-lSl) 125 

Nomenclature, 127 Methodi of formation, 127, Properties, 129 
AUMydf* (113-118). 133 

PropiTti(«. 133. Teals, 13fi. Foniialdeliyde, 137 Acctaldfr 
hydf. 1^ 
Kelt>nta (ii^i ii«] 199 

Acetone, 140. 
Th\rMiddi\fdt» nnd Thir)kelcmtM (Ul) 140 

ITNSATT'RATEU IlYIMlOCAtlllO.VB (133- IJ4) 141 

AikiHrnrx or Oirfinrn (i 32-1 19) 141 

Methods ot fnntijition, 141. Pnip'rl ii's, 142. Klhylrn^i, 144. 
Auiyleutrif, 144 The nalurv of llid double curbon buad, 145. 
Baeveh's tension thetirv, l&O. 
Peiymethylent compoundt, CnH,. (130) ISO 



CONTENTS. ix 

Eydrocarhona C.H,, _ , f 131-134) 150 

A. HydroearboTu with triple bonds (i3>-i33) 161 

Nomenclature, 151. Methods of fomutiOD, 151. Pro> 
perties, 152. Acetylene, 154. 

B. Hydrocarbons vtith two dovide bonds (134) 165 

SoBanTDTiON-PHOPUCTB oy THE Unsatdrated Htdrocabbons (135- 

138) 156 

Unsaturated halogen compounds (135) 156 

Vnsaluraled alcohols (136-138) 158 

Vinyl alcohol, 159. Allyl alcohol, 159. Propargyl alcohol, 160. 

MoNOBABic Unsaturated Acii>s (139-146) 161 

Adda of Ihe oleic series, CdH,. _ ,0, (139-144) 161 

Methods or formation, 161. Nomenclature, 161. General 
properties, 162. Acrylic acid, 162, Acids with the fonnula 
C,H.O,, 193. Oleic acid, 163. Elaldic acid, 165. 

Adds of the propiolie series, C.H,b_^Oj (145-146) 165 

Acids with two double bonds Ci.H,b_40„ 167. 

Unbatcrated Aldehtdes and Ketones (147-149) 168 

Unsaturated aldehydes (147-148) 168 

Acrolein, 168. Crotooaldehyde, 169. Propargylaldehyde, 169. 

Unsaturated ketones (149) 169 

Mesityl oxide, 169. Phorone, 170. 
CoupouNDs Containing more than one SuBSTmrriNo-aRoup (150- 

i6a) 171 

Halogen derivatives of methane (150-153) 171 

Chlorofonn, 171. Chloropicrin, 172. Methylene chloride, 172. 
Tetrachloromethane, 173. Bromoform, 173. Iodoform, 173. 
Methylene iodide, 174. 

Halogen derivatives of the homologues of m^hane (153-194) 174 

Methods of preparation, 174. Nomeoclature, and individual 
members, 175. 

Poiyhydric alcohola (155-161) 176 

Glycols or dibydric alcohols, 177. Trihydric alcohols, 179. 
Tetrahydric and higher poiyhydric alcohols, 183. 
Derivatives containing halogen atoms, hydroxyl-groups, nilro-grotips, 

or amido-groupt (i6a) 184 

POLTBABic Acids (163-177) 188 

Saturated dibasic acids, C,H,,_,0, (163-169) 188 

Physical and chemical properties, 1S8. Oxalic acid, 190. Ma- 
lonic acid, 192. Succinic acid, 194. Glutaric acid, 196. 
Electro-synthesis of dibasic and other acids, 196. Forma- 
tion of anhydrides, 198. Saponification of the esters of the 
dibasic acids, 200. 

Unsaturated dibasic acids (170-173) 201 

Fumaric and maleic acids, 201. Acetylenedicarboxylic acid, 
206. Affinity constants of the unsaturated acids, 207. Di- 



CONTENTS. 



ace(}-liii4HlieiirI)oxylir A<*id, 207. Tl>1^uu^crtyle^ediparbpxylic 
ftcid, 2tl7. 

Po)y&a»iC aeida (174-177)... 207 

TrilMAic widn, ZOS. Tetrabnaie Midti, 309. HighiT polybaaic 
aci<l«, 210. 

ScBSTiTirTKW AciDB (178-301) 211 

/ aogen-mbgtilHttd aeidn (178-181} , 211 

Mcthotls or fopRintion, 211. Properlim, 213. CUoioaoatie 
ncidx, 21:1. /J-ImlupropioDic lu-id. 213. Adds DonuUning 
moN than onp hn.l«(p-n ntmii 111 t.ht; moliM^ulu, 214. 

lirnielbagic hijilroj:ii-<tcuh (iSi-iSSi 216 

HelbnU cf fornintion, 210. rmprrlies, 217. GlycotUc aptd, 
219. l.aclii: iindu, SID. LocIodm, 223. 

Dibaiue hydmxv^rtilt {189-107) 225 

THrlmnic ni'iil. 22.S, Mnlie arid, 226. SivmrisompriBin of the 
turttu-iv iH'ids, 22ii. L'extro-iarianr ftcid, 33L. Ltcvo-tu^ 
laric iM-id. 233, Riin?tiiir •cid. 233. Mraotartaric »cid. 
'2'M. RAMiniic aubalanree iind thf>ir sFpaisiion into opitcidly 
active coiwiilHcnt.*, iS**. 

Polylninc Jiifiirojij-acitU (ipS) 241 

fitric iwid, 241, 

Amiit*f-acida (igQ-aoe). 211 

Mclhodn of formalion, 242. rroptniw, 343. l-iatCTs, 244. 
Indivkliud iiicnil<<-ni, 244. DiftJKMiwtir L><tM-, 347. 

DULDEtlTItEH AMI DlKETOMO*; IIaLOQEN UKRIVATn'Efl or THS Au>B> 

HVUKK AND Kktonrh (20a-xos) 248 

Diaidtki^dtx (MJ) , * 243 

iMtoone* (»03> 249 

DkMUjrl, 340. AMiylacetonc, 330. AcetonylftcetooG, 251. 

Ualoftn-tvf'tlithled aldtits*tn (m4) 231. 

Oilond, 2.')I. 

UalafftH-MjbittilMltfl ketot\e* ( J05) 2S3 

Ai-DEiiTBK AKO Kktoms .Xummuui uh .SvnAfiA (sofr-ajl) 254 

XvmmriatvTt and j/enerai propertif ol the monocM and Iktir deriva- 

lie«4 (M7-)o8) 3M 

Cotulihilum oj (A« iimimmm (309),, ..< , 2S7 

Unkodt of Jormation of Ike moaote* (ato) 2^ 

Mom^re* <aii-3J4) " 262 

Peotowa. 202. Itoxoir*. 264. Hrptogt*, 266. Ortosni, 209. 
MontMm, 2S9. SiereocliemMn- of tbo moBOMS, 3ft9. 

.Kmm (3is-»3l ■ 272 

Ualloac. 273. L*tioie or inilk.4i)[iir. 273. SttrroM or cane- 
sugar, 374. Manufacture oi emn^-tngnr, 376. Quantitn- 
tin Gstiinatjoa of canv-sugar, 277. ^'ctoci^y of inrmMB 
of auerow, 278. Fermeniatioa and tiie aelion of cnsyuia, 
379. 



CONTENTS. 



XI 



Potyote* (114-231) 383 

RaffiiWM, 383. Higher polyo^M, 283. Stuvh, 384. Mitnti- 
fociure ol rtiuch. 2S6. Clycogeii, 2S6. Ce'.liiloac. 2A7. 
Twhnical 8ppli«aIioiui oT n-1ltiio>>v, 2S7. Nitraivs or ccUu- 
low, 288. 

AuiNo-DKRivATiinn or tiib ALDEHTDEa Asv Ketoves (jji) 2S9 

Ai.i>EaTi>ic AND Kktosic .AriDH (133-340) 290 

Choxylic atid, 2)K). I'yraruceiiiic acid, 290. Ari-loiuMTtir acid am] 
Mvtoacrtic n>4cr, 291 L^vulinic tkrid. 293. Mpsooulle Mid, 
293. OxAlMwti« acid and oxftlact-tic cuttr, 296. AMtoii«dicu^ 
boxylic acid, 29*. 

Tautawritn (340) M7 

Plfmnt dcnmdVe* {14*1 3U3 

fL'^cttdcnik nrid, 302. Xanthorhrlidonic nctd. 302. DImethyJ- 
pyrone, 31H. TftrHvalciioy of ox>*(Cfn| 3tM, O-tonium anil*, 
305. 

Ctakooen Dkhivatives (141-147) 308 

Cynnoiewi. 308. Hyitrm^tuiir wid. 3IW IVnntdpii, 3in. C>"*nif 
iw-kI, 311. Tlii<K'yu)ii<T ncid, 313. MiintAr\l-uilt>, 31-t, Cyan- 
auiide, 315. Fulniiiuc acid, 3Ii. Cj'anuric arid, 31fi. Isoci-ft- 
Riiric ncid, 31G. 

I>ERiv.\Ti\'Ea or Carbonic .Acid (148-156) 317 

C«rbo&yl chloride, 317. Cnrlion disnlphidr, 318. Xanthic acid, 
318. Carbon ox>'sulphid«, SIV. Vn-n, 31(>. Biunt, 322. Scmi- 
cariiaiid*, 323. CarbBiiiic atid. 323. Urciliniics. 324. 'Hiio- 
uwfl, 325. Ciuaniilinr, 32B. Aniinm*-, 327. 

Umc Aa» fiiirmr (257- 158) 328 

L'ric arid. 32S. Parabftnic acid. 328. .\lloxan, 328. AllaxaniinP. 
32n. AUanloTnr, 32i). Malonvlnn-u, XHI. Violurio acid, 330. 
Aminolmrlnliirio nciil, 3.11). Psiiidii-iirir icid, 331. Hypuxtui- 
llunc-, 331. XaniKine, 331. Gtmnini}. 331, l'h<?ol)n)tnine, a32. 
CaiTctDv. 332. Punnc, 333. £ulL Viexaam'i ti>-iithtiiis of tlico- 
bromiiM) and caffeiine, 333. 

EUetro-rtdMtiMt of purine derivalivM (158) 334 

Droxy-derivativfH, 334. Purviie, 335. Tato.'b elcctru-rcduc- 
tion metbod, 33A. 



SECOXI) PART. 



THE AROMATIC (X)MrO[rNl>S AND SUBSTTANCES REtATEn 

TO THEM (159-41B) 338 

iNTRODVCTtON (l9«) 338 

PoL.TMETNTi.KNK l>i:Rn:ATiv»i (i6o-a6a) 340 

TrtmtiHijIene lierivtitiva (160).... 340 

Trtramfthi/tcne dericotitf* (lAi) •• 3-10 

J'€nlamelhyUne dtrivatives ()6)) 340 



zli 



CONTENTS. 



Ooaatnrunojf or BcsxEarE (163-364) 343 

Ctathc [onnuU, 310. NoateocUture and iaocarriBni of the bcD- 
tcDC (lcTi%-atires. 347. 

nilM'SnTO CBARAC-TtBtETIC OT TIIE AROMATIC COKfOTTyos; BtV- 

Timcs FROM i.vm (.'oMTOt-KPfl (a6s~i66) 349 

rn>ppni<--t nf \hr .vnruntir c(itn|MJiJiid<), 549. 8>-nlhi.'ees of aroniatic 
(lompounds from tlicup of the aliphatic aeriM, 350. 
KniEXK kso TUB Akomatk) Hvi>iKK\utuoNa WITH Satcbated StDE- 

CKAixK t>67-Z7a) 351 

GM-mAoufwiim utd iu b>--pro(lucU; tar, 351. Hethodn of (<»• 
UBtioD, &S2 Indi^HduAl mcmbcn, 3&1 Hvdragca odditioQ- 
prodtirU of the aronuiic hydrocarboiM, :i55. 
Ml)JCO«PMTiTrnox-nioi>t:CT« of th« AnouA-nc Mtsrocarboxs (»7I- 

a^i) 357 

Mvmmijiumieaeid»i37i'i 357 

JtfvmAiilegwKtvDipranift (171-37$) 35t$ 

Melboda of foimation, 330. IndividuAt tU'embcn, 330. 

iitm<A^nef^>tnoltandliTomaii£^da>hoU(l^^l•fi) 360 

A. Phcnola (374-J76) 361 

Mtitliod-i of formation, 3C1. Ptoperties, 361. IndividuAl 
mnnlwre, 382. 

&. Aronu>tic(tlcoii<>lB{a77) 363 

BenE)-! xlruhul, 3U3. 

Sulpkvr (Urxv<Uiv4M (377) 363 

TiiiupbiCDol, 363 
EttwnliyB) 364 

J/«»«mt/n)-»fon*tKl/i*rM (179-381) 364 

Mnliod of fonnatioii, 364. PrnpRrtim, 365. IntUvidu«l mcm- 
ben. .'Wfl. Fhi?ny)nitroniinlkane. 3C6. Pseudo-Bcids. 307. 

iJinuMimiruy-eompouitda <)8i'*S8> 368 

Melhuds of ftiniiation and propertlM, 36S. .Aolline, 370. 
Huiniilugtin* of iiniliiK!, 371). Si-t'uiiilArv auiioM, 371. Tor- 
liaxy luiiuusi, 373 Qii&lofiiary Laks, 374, Benxylomiue, 
372. Curbonir itcid drrirntivM of anjliiic, 375. ikdphur 
deiivativcN of Aniline, 376. 
ItUtrmediate prvivcU in Oit rcdiKtion of arvmatie nttn-wmpminda 

(iSo-ioi) 376 

Axavj'bonxnip, 376. Axobrnxpiiic, 377. HydniobvnxvtM), 377. 
Klectro-frduci ion of nitra-coiapouiidn, 378. 

Phtnjrl-ampOHniU cotOainijig alh£r flmmtl* i2Q3-J9S) . . 381 

Pbo^haruii and Aniom« d«rlvaUvM, 3St. CompAn»oa of the 
aroiDAtic dcrivAtivca of nitrogen, phosphorus, and uscnlc, 
3X1. .Aftiiiutlicf mrlAllic eoinpoundx, '.ixi. 

BcNzotc Acid and it» !)Ejtn'ATm» akd Ho«oi.ogi'c* (196-198) 383 

Sr-nzoir ni-id, 383. TVrivalivca of Leusoic acid, 3&^. UomoIogU'Ca 
of benzoic arid, 387. 



i 



i 



i 



CO»T£NTS. 



XIII 



rAOc 
hTto ALommBs AND KerOKKi^ (399-301) 388 

Buuutklchycle, and its hoinnluguM. 3Sli. Beaxopbeaooe. 390. 
HAeakkcm'h theor\' of tho «ynihi-j'bt of tltv unnuiic luMones, 3V1. 
ytwiwisouwrinm of the aroniatk o.xiniea, 391. 

i(xtiMrorNi)» AND Hydraiim:» (303-^5) 895 

iKtuo-nmt/iOMwiH (301-304I 393 

Uolhmls vl ftiriiiiil.imi, nnd coiidtitulion. Sy.'S. Rroctionn of 
ttu' liijuoniuiii compound.'). 3yi>, Haxtmcm"* llieory of the 
traDBfoniiBlioiui of the ditizoniiim rompoundM, TO8. Rvtuy 
twa« 11S the duuDiiLiun coiu|M}iinils in irtucb the mtn^co 
Btoma are not «Umiiiiit«d, 401. 

//yrff«n"ft«t [305) 408 

Ptienvlhyilnixlne, ^02. Mcthylpfamylhrdnuinc, 404. 

CoUPOTINtMtCoNTAlMKO AN L'.VKATUnATKD SlDE-CIUlK (3O6~3O0> 405 

HydrocurbouB, 4U5. .XJcobol* utd uidchv-dw, 405. .Vcids.. -106. 

Poi.V-«Ut»TITirrKI> llBaiVATIVDB COHtAUnHO SllitUAH t^UUBTITDKNTB 

(3to-33i> 407 

JWyjru//iAi7ntC««iii«(3lt).., 408 

PolyhalofftnilfTiiiUiveii(,3ti) 4()S 

Pvli/kyilrte fihenol)' (313-315) 409 

Dibydric phcaula. 406. Trihydrii: phenob, 410. Higlwr pli«u> 
oU. 411. 

QuinoMD <3i6-3i7) 412 

J*oli/nilro-derititlife9{itS) 414 

Foti/amMo-^omfiiituidtandthinrtbTitttliv*tlst^324) 415 

Phmylraediftininea, 415. Aao-dyvd, 410. 

PoI>/iM*it aeidii (3^5-331) 419 

Dibasic acids (Jjs-Jio) ^W 

PhthAlio Ac-id, 4111. l>rrivnii\'M ^f phllialie acid, 420, 
laophtliulit^ ami U'n'plitlialit atids, 423 

Htglirr |Milyliuneiu-iilii(33i; 423 

!tivATT<-£« CoKTAWtNg IVo OH MoBB Du«aiii4it SDBanrcsNm 

(S3«-M0 .;;;... 424 

Stitplio-Jfrindirtt (33^-335) 424 

Uokig^rn siilphonic ncids, 424. Phenol«uIphoni(? ncidt, 424. 
Sutplianilic itfid, 424. SulphobenxoCc actd*, 425^ 

/fologmdM-intfiivj (336-337) 425 

HiduReii |ilicii»l». ■i2i. Halogen b«iusoiic acids, 420. 

Ilstttmri/i-drr(nihi-r* (3S»-348) 428 

NitrOMtphenol, 42tt. N'itrophonok, 427. AminnphcnoiR, 4?d. 
MoQOhydfoxy-acidjt, 43U. I'ruof of the <t|unlity of the fix 
bydragcQ atotrw of bt^tuMie. 4:^2. Dihydroxy-scids, 434. 
1^ihydrox)'-««:ide, 434. Acid* containing hydrosyl or Mir- 
hoxyl in the sitle-<-liaiiiH, 4. IS. Hydro.xy-aldirhytkfl, 437. 

Compotii%iiavithtfunitro-t/rouparulamitU>-ifTvuii(,H9~$$i) 438 

IfitranilinM, 43S. NitrobenxoTc acida, 439. AmiiiobciuoTo 
addi, 430. 



SI* 



COSTENTS, 



ORI«KTATIOXOrAllO»UTICOoilTOCKI»S(3S>-lS7) ■Wl 

Methoda of an«ut«lion, AM. \\XmiiT.v.'* principle, 4-12. Abtiolutc 
dctenninolion of powtitin for ort/ia-cuntpoiuid.i, M2. X^saAyHt: 
detcrminalioa of pcwilion fur twin -ruinpoiinde, -144. Abeolule 
detcnainittioa of position for fMnt'Coni pounds, 44(1. Dclcrmina* 
lidfl vt pfniiion (or the triMibslilUKKJ ncd highcr-Huliniiluted 
dprivati«-vit. 4-1^. InJIiii'iiiv^of l)i« inihHtilui>uiKUiiuA4:li ottwr, -148. 

TBRFlCfsa AN t>(!AMi'Mi>HA (358-363) ' 4S3 

Properties, 452. Terpmu-s. 453. Camphor*, 455. The cgnslitu- 
tiou of thi^ iMpeuM and caiiiphor*, 43t), 
DKrtzKNE-NucLE] l>iiixcTLr LiKKKD ToaKTiiKit, OH Indkkctlt bt 

Oamron C3^-1^) 481 

Difihenyl (364) 461 

Diphmi/lmrlfione (365) 462 

TripheTiyinulh/tnf ami Uk denvativrs (366-367) 463 

Triphcnylmcthnnp, Wi. Lcui-onnUttchilcKrccn, 463. Main- 
cliiic'^reen. -JBS, Crj-slal- violet, 454. Panirosaniliiic, 46». 
I'nriUinicunUim-, ttiH. Kotuiuilitit.-, 4<i5. Mu^iita, ICi'i. 
Mvthyl'ViuUl, 4flfl. iVniJiut-bluc, 400. Rosolic ftcid, IQfl 
TriplicrvhiiHtliyl, 407. 

DAtm^andilsderivali}f»{3tA-3^') 467 

Dibciu)-!, 4(17. Sulbciit', ISS. Itrnstttii, 4(W. UydrobviuiuTn, 
4l>8. Beniil. 408. Beniilic acid, 4Q9. 

COHDKKMD UnNEK-VE-UIMOH (370-385) 470 

NaphlhaUne (370-378) 470 

Pn-panilion (rom cnal-lAr, 470. Propertie*. 470. Coiuttlu- 
lion, 471. Number of 8iihBtitutii>n.pti>diio1«. 472. Substi- 
tution- prod or In. 473. .Wditiim-produirlo, 477. 

Anthraetne (370 3*3) 478 

Prt-porikiiun from coal-tAr, 470 Properties. 479. 0>n«titu- 
tioii. 4"!». KiiuibtT of aubttiituiian-pniducta, 480. Subati- 
lution-pr<Kb«'l>!, 480, 

PtenanfAfwi* (384) 488 

Prepfiration fnim tvwl-inr. 4.'W. Propertiw, 4R6. ConrtllU* 
lion, 485, Phenonthrfiquituinr, 48fi. 

Fluorantfient. purrnt.iiH'l rhryjienc (iis) 487 

HrrKHf«rm.ir('oMPOL-so8 (386-394) 488 

Pj/ndinf (386-390) 488 

Preparaliou froui coal-t&r, 488 Properties, 4S8 Ccoatitu- 
tion, 489 Hoiuologues, 491 Pvridluecuboxyliu acidt, 
493. 

Fur/unnt (301) 496 

CoiiHiitutian, 496. Pn^panttioD of furfurati denvutives, 498 
I•^lrfll^dlIchyd«, 497. Pyromurio Mid, 498. 

/Vrofcfa^P) • <M 

PmpnrKltun, 49& Propprtim, 499. Cbaililulion, 499. 
PolftaBto-pyrrolo, 400. DihydropxTTok, 499 



CONTENTS. XV 

nam 
Thiopkcn (393) 499 

Pynut^e (394) 602 

Sj-nthesis and coostitutioD, 502. Pymzoline, 503. Pyrazo- 
lone, 503. McthylpbenylpynusoloQe, 503. Antip>Tine, 503. 
Condensation-products of Benzene and HBrEEOcrcLic Nuclei (395- 

399) 505 

Qutrwiine (395^396) 605 

Syntheses, 606. CoDstitution, 506. Orientation of quinoline 
derivatives, 507. Nomenclature of quinoline derivatives, 
508. 

Isoquinoline (397) 508 

S}-nthebis and coostitution, 50S. 

IndoU ii9&-399) SOO 

Relation to indigo, 509. Constitution, 510. Skatole, 610. 
Indigo, 610. 

AuuixitDa C400-411) 514 

Propertieit {401) 514 

Extraeiion from planU (402) 515 

Indimdxml alkaloids (403-41 1) 616 

ConiTne, 516. Nicotine, 516. Atropine, 516. Hyoscyamine, 
617. Cocaine, 517. Morphine, 517. Narcotine, 518. Qui- 
nine, 618. Strychnine, 519. 

Ajubumins (412-418) 520 

Composition, 620. Salting-out, 521. Coagulation, 522. Dena- 
turation, 622. Decomposition-products, 522. Tests, 523. 

CtoMi/fcoIwm (415-418) S2i 

Native or true albumins, including the albumitu, gltAulin», 
coagulahie albumitu, and nucleo-aBnimiju, 524. Decomposi- 
tion-producU of the true albumins, including denatured 
aUmmins, aVmmoees, and pepkmes, 524. Protelds, including 
nvcUo-proUids, hcemoglobim, glueo-jtroteida, and a]bamino\d», 
624. 

Svb^arux8relaiedU}thedlintminoida{4zSi 627 

Bpongiu, 527. Fibroin, 628. Sericio, 528. Sericoln, 528. 
Comein, 628. 



FIGURES. 



FIRST PART. 
notiBB rkon 

1. Org&nio analyss 6 

2. Potash bulbs 6 

3. Tube furnace 9 

4. Victor Ueter'b vapour density apparatus 14 

5. Etkuan'b depressimeter 19 

r>. Etkuan's graphic method 20 

7. McCoy's boiling-point apparatus 20 

8. Heating substances in an opeiL flask 23 

9. Flask with reflux-condenser 23 

<0. Distillation apparatus 24 

1 1 . Fractionating-flask 25 

12. Distillation in vacuum 25 

13, Fractionating-columns 26 

14, 15, 16. Vapour tension curves at constant temperature 28 

17. Steam distillation 29 

18. Separating-funnel 30 

19. Filtering-flask 31 

20. Determination of the melting-point 32 

21. Pyknometer. 33 

22. Laurent's poIarimet«r 34 

23. Fractionating-column 54 

24. Carbon tetrahedron &4 

25. 26. Asymmetric C-atoma 65 

27. Solubility curve for trimethylamine and water , 87 

28. Usual form of solubility ciir\-e for two liquids 87 

29. Melting-point curve of the fatty acids 103 

30. Preparation of vinegar by the " quick process " 106 

31. Graphic representation of the melting-points of the acids CnH,B_,0,. 189 

32. Hofer'b apparatus for electro-synthesis 197 

33. Spacial representation of the bonds between 2-5 C-atoms 200 

34 . 35. Single bond between two carbon atoms 202 

36, 37, 38. Graphic spacial representation of the double bond between 

two carbon atoms 202 

xvi 



CONTENTS. xvn 

no CUE FAOB 

39. Fumaric acid. 204 

40. Dibromoeuccinic acid 20i 

41. Maleic acid 204 

42. Isodibromosuccitiic acid 204 

43. Dibromosuccinic acid 205 

44. BromomaleTc acid 205 

45. Isodibrotnoeuccinic acid 205 

46. Bromofumaric acid 205 

47. Erucic acid 214 

48. 49. Dibromoerucic acid 214 

50. Brassidic acid 215 

51, 52. I>ibromobra8Bidic acid 215 

53. Acetaldehyde 221 

54,55. Lactonitrile 221 

56. 57. Conversion of an optically active substance into its optical isomer, 222 
58, 59. £mil Fischer's spacial representation of two C-atoms in union. 228 

60. Klectrolysis of an alkaline copper solution 232 

fil. Maleic acid 235 

62, G3. Mesotartaric acid 235 

64. Fumaricacid 236 

65. Ifaeemic acid 236 

06 Crystal forms of the sodium ammonium tartrates 239 

67. Rye-atarch 283 

68. Rice-Htarch 284 

69. Potato-Btarob 284 

70. Normal reduction curve 336 

71. Abnormal reduction curve 336 



SECOND PART. 

72. Habub'b ■cfaeme for primary and secondary reaotiOM 380 

73. Solubility curve of ben«>te aoid in water 386 



ORGANIC CHEMISTRY. 



INTRODUCTION. 

1. Organic ChemiBtry is the ChemiBtry of the Carbon Com- 
pounds. The word " organic " has now only a historic meaning, 
being derived from a time — the beginning of last century — when 
it was thought that the substances which occur in organized nature, 
in the animal and vegetable kingdoms, conld only be formed under 
the influence of a special, obscure force, called the vilal force. 
Several unsuccessful attempts to prepare artificially such "or- 
ganic" Bubstances promoted this belief. Until about the year 
1840, it was so general that Bebzelius still thought that there 
was but little hope of ever discovering the cause of the difference 
between the behaviour of the elements in the mineral kingdom 
and in living bodies. Organic chemistry included the study of 
those compounds which occur in plants and animals, as well as of 
the more or less complicated decomposition-products which conld 
be prepared from these compounds by various means. Among 
the latter many were known which did not occur in nature, but it 
was thought impossible to build up a compound body from its 
decomposition-products, or to obtain an organic compound from 
its elements. 

In the year 1828, Wohler had indeed obtained from inorganic 
sources the organic compound urea, a product of the animal 
economy. This discovery was at first regarded as of small impor- 
tance, for it was thought that this substance occupied a position 
midway between organic and inorganic compounds. For a num- 
ber of yeara the synthesis of urea was in fact the only well-known 
example of the kind, such observations becoming more numerous 



ORGANIC CHEMISTRY. 



about the middle of the nineteenth century. The ^Yiithc-sis of 
many sohstancep, inclmling that of acetic acid by Koluk, anit of 
the fata by Blktiiklot, strengthened the con\ictioii which had 
gradually arisen, timt organic cciuiiouutls aro fornuid under the 
influence of the same forces as arc moi^ganic, and ttat to this end 
no s])en'iil force is neeessary. 

The natiirnl division between organic and inorganic chemLstry 
waa thus deployed, its place being taken by an artificial one. As 
it had been already noticed that all organic compounds contain 
rsrbon, the name "Organic Chfniiytrj'" was appUtrd to the 
ChemiMnj of the Carbon C'onijmvtulit. 

TIiiKingh lh»? nunieroiL'' flisniverien wliirb vr^re made in this 
departtiient of the seience, esprciully in CM-rniaiiy by Linma, 
WoliLKR, and thtir pupils, and in France by Dumas, Laurent, 
and (ir.t<nAHi>T, urKauic chuni^lry jn^uaily acquired a totally 
difTcrent aspect, and the old division imo groups of aubstanoe* 
which had either the same origin, as in the case of vegetable 
chemistry or animal chemi-^tn,', or had singlp properties in common, 
us for example the vegelable airlds, the vegetable bases, and ncntral 
vegetable IkhHc;!, vanifihod. Ite place -was taken by a more rational 
claiwificatiuti. which Kraduully devilupcd into its presMiut fomi, and 
is based on the unitunl ivlatioi\sliip^ which &ro found to Q\\»t 
between organie comjioimdi*. 

2. Since no e>wential <)iKtinetioti IxMween organic and inorganic 
chemistry now exists, and niimerons ^ynthesps have set at rest 
all doubt aa to the theoretical possibility of building up from their 
elements even the most cnniplicated carbon com|KPunds, such sti 
the albmiiinii, the (luestion may arise as to the reason why the 
chcmiBlry of the carbon com|xmndg ia still treateil as a spoeial part 
of the science. The answer to lliis question is based upon two 
I'caaoni^. 

Fire*, the enormous number of carbon compomids wliich are 
knonii. Tbix amount^^ to many thoueaml^.* and is greater than 
that of the compounds of all the other elements. Second, the 
properties of the carbon compounds. These are either not found 
at all in Umj couii>ounda of other elements, or at least in a much 
less marked degree; for example, many inorganic com|iounds 

* Bwentjr-Bvu tiioscaad euntpouBda aro nwatlonod la tlio dleUoou-y rooeatly 
jnbllfkfd by M. X TitcBna. 



Q^'MUTATiVF. AtiALYSiS. 



Guu be axpoutil lo Iiigh ttiin{)€Jiilurv8 witlioat aDd«rgoiiig &117 
cWntica] cliangc. wborciu tbc cu-Wu coiupouDda. almost without 
cxvcption, »iv d«coinpoHe<l at a red lieat. Ah & rciiuU of tliiK, the 
latter nro gcDernlly miioh loija stable Uiuii ihu foriiit;r towards 
chemitsl and plijsioil ivaguou, aD(] tbas differeut toeUiods are 
vniptoi,*^ in Uie inTestigutiou of tbc carbou com|M>uuda aiaA of 
tht) inor^iic uomputinde, 

A lurtbcr iwculjurity lis tbul oiuiicrous or^aic compouods 
have exnclJy the suinjo com]>oeitioii, but differ very much from one 
nnoilior in propcrtitu. bur ciamptR, up Lo tlio ypur 1900, iiigbtjr- 
two compoiintla of tJie formula C',fl„0, had been discovered. 
This phenomenon \» vmWvA itoinerism, mid is idmust unknown in 
inorganic cliemiHtrjr, » fact wliivb iivKcm\ia\«a an itivcaiiguUou of 
the cause to which it is due. 

All thc«e raiuoiig mutce it doiiiriible Lo treat the carbon oom- 
pounds iu n special piu-tof ch«iiiistr\-. 



r 



QUALITATIVE ASD QUANTITATIVE ANALYSIS. 



3. Inveeligntiou has xhown tbut in Ibo lUHJoritj of the 00m- 
|w>uud« of carbon, there only occurs u very smalt number of 
uleiliODta. Tbo chief of these are carbon, hgdrogirn, oxygrn, and 
Hxtrofftv. Halofftn derivatives arc leas riiimeToiiK, nnil siihataiices 
eontaiaing sulphur or phosfjhoroua occur atill loss frequently. 
Carbou compounds are alee known in which other elements are 
found, but tliey are exceedingly few in comparisou with those 
which contain only tbo oloments Ttamed aboTu. Some olomcnts 
do not occur in carbon compound!. 

[u order to be able to determine the nature of a comjionud, it 
lA fint of all ueceawry to ascertain what elemente it contains by 
anbmitting it to •juatHatife aitaii/tit. In the oaa« of the carbon 
compoanda, this is very simple in theory, the procese Iwing one of 
oxidation. This converts hydrogen into water, □itrogeo is liberated 
in the free stat«, and the other clemeula are brotight into the 
form of simple oompouuds (carbon diuxido, aulphurio acid, phos* 
phoric acid, etc), which can than be detected by Uie ordinary 
tcactions of inorgaoio analysis. If an oigiiaic compound contaiiu 



ORGANIC CHEMISTRY. 



a halogen, it must bo osidixed berore the latter pan be dotoctod, 
siacQ Dto hnlogcng nro not tiiniatly split off iu the fomi of ions b; 
mere Holutton of their nrgiinic L'onH)oiiiui8. mid t-annot thwrpfore 
he recogDiBcd hy the simple additioa of *iU'cr nilnito. W'hou 
such B compuutid is oxidized in. jHrMenoe of eUver nitrate, tbts 
eorrcepondinji silver halide is formwl. Other elemonta which may 
be present are found, aft<?r uxiilatiuu, in the form at cnmpoiinds 
which ttr« easily id(*iitUied. 

For iinatjticnl jiurpoee^. oxidutioii is currird nut in different 
vruys, aooordiiig to the nnture of tlio elmiioiit wliosi; pmsonce in 
suspected. Copper oxide is generally used in tcstiug for carbim, 
hydrogen, and nitrogeu. Tho »itibslanL-e ia mix<ni with it, and 
the mixture ia hontod in a glues tiibu 8(*iilt>d at one end, tho mrbnn 
and hvdrogen bemg oxidised by the action of the oxygen of the 
copper oxide. Nitrogen ia evoWeil in the fru<; statt. and can he 
recognized iu exactly the same way an iu the qunutitutive Hiialysiii 
of nitrogen (T). In the cue of the hulogens, sniphnr, phoepLorue, 
etc., it is easier to oxidize the subdtanoe under examination vith. 
ounceutrated uitrit; ucid. 

The method of oxidation ib a general one for qualitative H.naly- 
iis; it can always ho applied, and yields perfectly roliable result*. 
There are iu addition other tuethorls which in many cutset! atta.in 
nred end more qnickly and easily, but as most of those 
Soda arc not of universal application, the fnJiure of one of 
tliem to detect an element affords nu certain indication of its 
absence. In doubtful ca^ea the ci^uestiuu inuat he decided hy the 
oxidation proccas. 

For example, the presence of carbon can frequently be de- 
tected by euboiittitig the subatancc to Avy distillatiou. Charring 
often takes plare, or vapours are evolved which can be recognised 
as carbon compound* by thi<ir ann^ll or otIi<.'r properties, such as 
barning with a suioky flame on igiiitiou, 

4. The nitrogen iu many organic compounds can be converted 
into ammonia by heating with soda-hme, or with concentrated saX- 
phnric acid. Another method very largely naod in teeting for thi* 
element was aagge.tted by Lassiigne. It couaistii in heating the 
snlxttanco nnder examination with a stnull piece of Bndium (or 
potassium) in a narrow tube scaled at one end. Should the com. 
ponud contain nitrogen, sodium (or potaseium) cyanide is formed. 



QO^NTnjnyt analysis. 



S 



its presenou bciug easily recognized by uoiivertiug it into FniiKiun 
t>lu«. 

Thia t«et t9 o&rricdout aa foltows. Tb« tube wiiti its contoaia, iiflo' 
liATiiig been lieritod tit redmsc, ix inoinened in n little wai^r, where- 
upon it crftcks, (iiitl the alkiklinc cyAoidf which has been rornicd dia* 
solTec. To ihU is nddod jl clroii ut & Eolution oonlainin^ a ferrnuit nod 
ferric salt, and then a, little dilute hydrooIiloHc »dd. ShoiikJ nn nika- 
lino cjranlde bo present, ic Ig conrerted into PruMlnri blue, Toriuiiig » 
Uuo procipilntc in tfav liquid, 



5. Tlie halogoiiB may bo recognised by heating the subatanL-e 
with qiiicUime, the corresponding calcium hHlide being formed. 
A very dclicjite method of detecting tliem is to iulmdticv a littlu 
of the compound on a piece of eoppcr oxide into u colon pIvkk flume. 
The corrcspoadiog copper halide ib formed, and Toliitilizes, impart- 
ing • magnifiront green colour to the flame. TboBO tvo methods 
an nlwara applir4ibia. 

Snlphur can often be delected by heating the rnmponnd with 
B small piece of eodinm in a iiarmw igiiliinn tnbe. Sodium nnl- 
phide is produced, und cuu bo dutficlod by trejiting tho reaction- 
mixtarc, placed on a dvuu eilvvr coin, with wati-r, when a Mack 
stain of eilreritnlphido in formed. Or, tho roaclion-mixtnro may 
b« extracted nith wutur, iind sodinm nitropnietiiun added to 
the Bohition, which tlion actiuireK a dnop-viol«t coionr. 

Ko mention ha« here been miido of oxygnti, beninRe no (pialita* 
tive rearition \s known by wliirh ib may bo tested for in an organic 
compound. Itti prcecscc cau oiily bo detected by quuntibilive 
anftlysis. 

6. Following nn qualitative, mnst come yuantUaiive analgnt; 
thai IB, the determination of the qiianCily of onoh element present 
in t1i» compound. The methods n^ed for qualitative nualviia in 
tnorgnnio chemistry are ofl«n very different from those employed 
in quantitative detemiinatione; in organic ehomistry the methods 
«f qualitatire and ([iiantirative analysie are alike in principle, 
«ztdalion being madv use of in both. 

Carbon and liydroyen are alwavg estimated together. The 
principle of the method of organic analyeia which h ehieAy asod 
was worked ont by Liebio (1803-1873). It is usually carried out 
aa foUovfl. In the combustion furnooo, k (Fig- 1), is a hnrd gluss 



ORGANIC CHEMtSTnY. 



tobp, ah, open At both ends. A e(Kn[det« dnviiif; nf it is shows 
in the figure sbore the furnace. It u panlv filled with grvao- 
cuppcr oxkIv, j^, antl with a tpin) nf copper gwue, r^ 
rbich liM bem ou>!txed br htsting to nellies in the sir or in a 
frtrcam of uxYgcu. About one-third of the Icn^h of the tube is 
kft «mpty, uhI into this, after rcoiOT*! of the copper epird, a 




pUtinam or porcelain boat, d, contiuntnj: a vdgbud qtuutitjr of the 
sub8tanc« to be analyzed, \a inlrodaced. The «nd of the tube next 
the boat ia connected with n dryinjt-apparatng, j, k,j, in which 
lh« air or oxygen is frveil from water-vapour and carbon dioxide; 
g contains oonceDtrated caustic potash, h wda-linie, and j calcium 
p chloride. To the end of the tube fnfthest frnm the hi«t is 
'attat^hed a weighed calcium chlnnde tuho, ^ for the pnrpose of 
collecting the water produced bj the combustion of the subetauce. 

Thewcighfii potjwh bnlbe, m (shown 
enlarged in Fig. 2), are wmuected to 
tliiB, and in them the carbon dioxide 
formed is absorbed by concentrated 
raiietic potafl). The gasee enter the 
appantns by the tabe b o» the right, 
pass through tbo three btilb^ con- 
taining jKituiih. and ivcape through 
the uilw ir, which is 611ed with soda- 
iDie. As Boon as it is certain that all the joints of the apptmtus 
tare gas-tigbt, the burnere are lighted, except lienenth thi? pliirc 
wbora tho boat ia. Wheu the tube is hot, tho substance is biirnod 
by carcfnlly heating this part of the tube, while at fir&t u sloir 
fitroam of nir, imd later a slow Htream nf orygon, are IchI tfarongll^ 
the dn,'iug>a])paratus into the tube. The oxygen has tho effect of 
hamtng more easily and quickly the purticles of carbon which han 




Flu. S. 



QUANTITJTIVS ANMLYSIS. J 

depoeited, and the red-hot copper oxido Berrea to fuilj- oxidiio th« 
ga^otie (iMompositktii- products to carbon dluxidt- aiiil wi4l«r. 
The iDcreiwe id weiglit of tlio calcium chloridu tubu and of the 
potadh bulbs gives the <)umitity of water and curbon dioxide 
formed, from which thu amouut uf hydrogen and carbon in tite 
com|)Ouiid m&y be colcitlntcd. 

Hhunld the compound contain nitrogen or halogens, a freeU;- 
rtduced spirul of copper is placed at the end of the tube next tbe 
absurptiou-Bpparatus I oiid ui. The liot capper decomposes atiy 
nitrogen oxidea which may l>e formed, and which would othorwiae 
he abuirbuil in the pntatih bnlbs, and at thv eamr lime combiner 
with and retains the halogens. 

Sonivtuiies Ihv atudjvu in varriml out io adiffeirent manocr, the 
Mifaatanee to bo analyzed being mixcHl wiili fli]«lv-[>ow(lAretl cnfp«r 
oxide and heated in a tubq drawn oot at one end to a finu [mint in 
the Bbapo of a Ixiyonc-t, and coaoeoted at iho oilier u-ith the alwirp- 
liou'nppamlus. In order to di'ivo over itilo tbe uboorption-apiwratuA 
the water-vapour and carlran dloilde nhicli runiaiu in ttio IuIm after 
the combnstioii, the poiDl of tbo lube ia brokeo, and a atrentn of air 
drawn gradually through Ww wtmlu appantes. Sabauuees whici) 
bam with great dilGcully an- mixed witli lea<I chremate iusleod of 
eop[K>r oxhte, t))o [Drmor being Die mom eiiurgelic oiuliEing-agenl. 
This nnbatanuc U «Uu uaed wliun tlie compound conLains sulphur, (he 
• SDlphur being oourorletl. by btnitiiig in mulact witb tbe chromate, 
into lead aulfbate, wbich ii »lablo at rod beat. If copfior oxido is 
UMd. solptiur dioxide \» fonnsd and 'm absorbed in tbo potash bullie, 
tboroby iiilrodu^itiK an error iato ibv cjtrbou v»ttinattoti. ihnoiher 
method of retaiiiiiiK Halpbur dioxide coimtitlft In 1i.ivmg a layer of lead 
dloxtdo, I*bO( , al the end of tbe tub« next to Ibc absorptton-appn- 
ratux. Tbia layisr i» gently liealed, atid tnkea up all tba aulpbur 
dioxide, with forauition of lead lulphate. 

7. Xiirogen is uaoally e-stimated bj^ Dchas' method. A 
weighed quantity of the subotoncr^ia mixed with finely -powdered 
copper oxide and placed in a tnho closed at one end. A euhstance 
which on heating eaaily OTolTea carimn dioxide ij prerioaaly placed 
At the end of tbo tnbo, magne«iiim carbonat^ being often uK-d 
for thin purpose. The remaining spaoo is Oiled with grannlsted 
cfjppur oxid(Jf Stid a roll of dean, freshly- reduei-d coppwr gauzrU 
pUced at tbe end. The open end of the tube is closed with u 
imbbcr stopper Htbed with a delhrery tube, the end of which dipa 
Bnder mercury. Aa eoon aa the air hiw Iteen dri^uuigit of the 




> 



k ^ 



s 



ORSANIC CHEMISTRY. 



appantns by heating the mugnesium carbonate, the front part of 
thu tube, contaiuiiig the copper Bjiiral uqiI tho granulated copper 
oxido, is hcAtcd. The combtistiou U then begun, acd thv evolved 
goees are collected in n graduntod tube oi^OQ at the bottom 
(measuring tube), the end of which dips into tho mercury bath, 
and which is filled partly with mercnry, and partly with couw'n- 
irai«<l caustic potiwh lo alMorb the carbon dioxide. The r«xlucttl 
copper spiral haa the effect of decompoBing any nitrogen oxiJm 
which may be formed. The magncsiuni carbonate in again hctttc^l 
a& soon od the eoiiibuiitiou is over, tho ciirboii dioxide evolved 
driviiig all tho nitrogen raniaining iu tho apjurotna into tho 
grudu&lvd tube. Tht* latter, along witli the men-ttry, pulaidi, and 
^iK wliich it contaiiiB, is then placed in a wide c^iindvr fdli'tl with 
water. The mercury and potash are displaced by the water, and 
after the level of the lii^iiid ineide and oiitf»ide the tnhe ha« Ifvua 
made to coincide, the number of cubit! c^ntimetrea of nitroj;en is 
read o(T. From this thu amount of nitrogen in the compound is 
calculated. 

In many cti«e« nitrogen may be estimated by a mcihod which 
waa dtacoTerud by Kjeuiarl and improved by Wilfarth. It 
.epoiidd upon the fact that the nitro^u of many organic sith- 
nees is wholly converted inio ammonia when the compound ia 
healed for some time with cunceutruled Giilphurie aoid in pre«enDe 
at phosphoric nnhydrid*' and a drop of mercury, thu latter goini; 
into soliititm. Usuully tliu mixtiirL- tlrst turna blat-ii, owing to 
charring; uftcr heating for one ortwu hount. a potut ie reached at 
which the li^inid a^idn becomes perfectly colourlcw. The carbon 
h»s then been fully oxidized by the oxygen of the sulphuric acid, 
which III reduced to Kulphurouo acid. The pmcess is facilitated by 
the mermiry ftilt, which proltably plays the part of an "oxygen 
carrier " between tho sulphuric acid and the organic Bnh«tane«. 
being continually converted from the mercuric to the mcrcnroiu 
st*te, and then liaok again by tho boiling acid into the mercuric 
state. :V8 B'ton IU the lii)iiid him lK><^)me colonrle^, it i^ idluwod 
to coul, dilntMl with water, excetu of alkali added, and tlie am- 
monia distilled into a measured (|iinniity of acid of known screngih. 
By titrating, tho i|aantity of nmmonia is found, and hence the 
unouut of nitrogen. Thia nrttt and eatnr method is nenalty not 
applicable to compounds which contain oxygen 'inked to niiro- 



Ql/MKTtTATtyE ANMLYStS, 9 

en. Iq this citsa the latt«r element is uulj' pATtially oonTort««I 
into nmmoniH. 

8. The hnlogens can be eittlmafcod by tbo method rithc-r of 
LtEBici nr or CAiiii.'& In tlie former. Uic subatiuico ta hcsteil with 
<inicklime, atid in tliolaltcr, at a high tcmperAturo with a littJo 
conoeutrnted nitria ncid nnil n cryntiU ot sih'or nitrato in n ^.alcd 
glaes tube. This is uurricil out withont risk in the tube furnw<« 
(Fig. 3), in which the gUas tubes are placed in vrroaght-iron 
CTliodere with thick walU. 




Fig. 8. — Tcbe Fvrjiack. 

Oabius' metho<l can also be applied to the estimation of sul- 
phur, phosphoras, etc, Non-volatilo subHiflncM containing sulphur 
or phoaplioniB can also be oxitlized by fiittiun with 3iitrc. 

9. Th(! results of a quaiititutivo analms are oxpreiued in per- 
centage-nnmlwrB. If the total of tlieae percentage -numbent is 
YtiT nearly 100, then no otiiur elements arc present iti tbi- tom- 
pounil; but if appreciabl,v leits than 100, there is aiiottier olu- 
mcnl preKut which hm not been taken account of iu tliv Nimlysis, 
becaoH there U no suitable method known for its estimation. 



IC 



otiCMac aiEBtBTnr. 



Thm {II witig>-— Bnt of eajg/m k 
tkntec iomad hj mihume^g tht tocal el (be pe wif M of 
Cl» Mlbn- ill ■mil froM IM. TUi hm the dwdnatape that 
Ac OTon «l npariflwaA arc all JadaJirf m Uw iftrtntTr -TTini- 

I an wmDj too lev, e«b« to tke )•■■ of ft Euie 
I ikioaiji lk» varioM cocnaettona of iha ^faeataa. Tbe 

an f ir a Oy t*o Llfb, biMii oeppcr oxkW b 
hyfraaufit. aad can oolf fae baed fna tnoea frf BoiKan vUli 0nai 
4MotII7. Ifecaa crron baUnw «ea aMthcr iMve «r Ina. an Umi 
Urn «aai «f aflconey in tba otjfm ptnsaotaft to rthnfailabeJ. 

Tbe netliod bj whirb tbe prrecetagc-eoaipoeittofi and fonnuU 
of a MilMaiiea are c&lcnUtM] from tba molts vi analrau u best 
fzpUined br una or tvo euunjtlea. 

tnnt tUampU. Tht fuUovlBc aamben van obuliwd In tbe 
saaJjab of ■ rabatancv : 
<«» tt.tmi f . Hibilanee gave 0T4M g. 00, and 0-1U8 %. HiO. 
gl) 0>2170 s. aufaataoec gave 0-«4I4 f- COi aod 0-13d0 g. H.O. 

Hbm |1mt« an 13 paru bjr welgfat of in U {arti bf wei^ bt of 
COi, awl S parts b/ weichl of li to 18 pnru bj neigfaC of H(0, (be 
nnmber obUioad for CU. must tia nmllipliad by H = ^ to fiod tbe 
■mount of 0. and the Dtuabet fbutul for II^O by f, = ) to obtain the 
■inount of D. 

{a) 0>2Sei g. HifattauoB contain 0-9087 g. C and 0-0181 g. n. 

(&) ai70g. flubntanoBOontait) 0-1740 g. C and 0-Olfit g. H. 

In order tn oakniatn from ibis tbe pormotag^nurabera, tbe figuree 
fmud lot C aiMl 11 niiiat bo dividnl by tbe neigfai of siibntuticc uwd 
la the analyiia, and tlie quotient multiplied bjr 100. Tbis give* 

((I) 80-8X C and 7-« H. 
(ij CK)-i» C and fl-W K. 

BltHW tba sua of Q and H u 67-8 in (a), and 87-S in (&), tbe com* 
pound aaaljiad mutt couuln oi/gun. According to (a) tbe per- 
ocolage of thiaelemeol it 13-3 ; according to (6) it in 13-1!. 

The moan of tbe two aualysee giree tbe following {lercentngt^-ooni- 
poditoQ for tbe mbatUMo : 

OBO-T 
H 8-ft 
OlS-4 

The Atomic fmiglit of carbotkia 13, of hydroRen 1, and of oxyg:eQ 
19 ; la order to find tbo ratio of tbe number of tbo atoms of theee 4le- 



QUANTITATiyE ANALYSIS. " 

ments in the compound, tbeir atomic weigbta mast be dirided into the 
perceatage-aumbers. From this we obtain 

C H 

6.7 6-e 0-8 

Since tliere cannot be less than one atom of each element in a 
compound, and since the figure representing the aamt)er of atoms must 
alirays be a whole number, we moat divide the above ratio by 0-8, 
which maizes = 1, and the other numbers as follows : 

C H O 

8.7 «-0 1 

It is evident that the ratio of the numbers of the atoms is verj 
nearly 9:9:1, which corresponds with the formula CiHiO. Inversely, 
if the percentages of carbon, hydrogen, and ozygen be ci^ulated for 
a substance of this constitution, there is obtained 

081-3 H6-8 012-0 

which approximates to the mean of the reanlta of the analyses given 
above. The simplest or empirical formula of the substance ia there- 
fore 

CH.O. 

Second SocampU. The analysis of a substance coDtaiaing nitrogea 
gave the following numbers : 

0-2169 g. substance gave 0-6170 g. CO. and 00685 g. H,0. 
0-2218 g. substance gave 17-4 c.c. H, measured over water at 9* C. 
and 762 mm. barometric pressure. 

The weight of the nitrogen is calculated in the following way. 
Since it is satarated with wat«r-vapour, the tension of this expressod 
in mm. of mercury must be subtracted from the barometric presaura 
in order to obtain the true preaaare of the nitrogen. At 6* C. the 
tension of aqueous vapour is 7-0 mm. The actual presaure of the 
nitn^n ia therefore 763 — 7 = 756 mm. Since 1 c.c. of nitrogen at 
0* and 760 mm. weighs 1-3562 mg., at 75fi mm. and 6* C. the weight 
of this volume expressed in milligrammes is 

1-2562 ,34s ^_^jjj^_ 



1 -f6 X 0-00367 760 

Therefore the 17-4 c.c. of nitrogen obtained weigh 1 -3311 x 17-4 = 
91-247 mg., from which the percentage of nitrogen is found to be 9-6. 



»a ORGANtC CHEMISTRY, 

B; npplyiDK tlie oietbod dncribcd in Ibo fii«t csa.iii]>l<>. llio per- 
centage oi c&rtton a.nd hydrogen is foand lo be = Qfi-0 and H = 8-S. 

Tliesainof thcaoporc«t)tago-t)Uiabenisi8-l, BO that the perc^ntase 
of oiygvn in the suhstauoe ftaalyzed is 31 -9. The perceat&ge-coaipoBU 
tlnn givcu \>y tb« imalysia is therefore 

C 65' 
H 8-5 
N 9-6 

On dividing ih«so valaes by tho Rumbcrs repreeenlinK the Atomic 
velglitA of 11)0 coiTcspuitdiug eletDonts, w« have 



C H N 





54 8-5 0-7 


1-4 


Tboee DamborB divided by U>7 give: 




c n N 





7-fl 51 1 


3-0 



Tlieeo numbora approximate very closely to thom required by the 
formula CtHtKO>, The perceutagc-oomposiiioii correspoDdiog to Ibis 
formala is 

Ces-S HS-4 17 9-5 

« 

whfob a^es we]l willi tli» aiiiilysis. 



DETEEMIJrATION OP MOLECULAH WEIGHT. 

10. Au aiialjflis nnly gives the cmpiric»1 fonnuI» of a com- 
pouiiil, and not ita molocular formula, because C'^UlOo Ims the 
same pen-i'jiUge-oomjiui-itjtiii iw (C,H,jO,)„. Wlieu the i^inpiricul 
formula has been «8c«rt«ino(l by analysis, tho moiecitlar weight 
hati Hiill to be dpt«rmintjd. 

ThU cannot bo decided by chemical mvaiw, although it is 
poaaihle to thus obtain a minimnm value for the molecular WL-ight. 
For example, the empirical formula of benzene is CH. There is 
eoiiily obtained Irom benzone a H:<>mpoimd, C.II^Br, which ran be 
reduced aguiu to huuzeite. It follows from ihU that the molecule 
of this mibstanc* iiiudt he represented at least by C,H^ The 
molecular fonnuU. Iiowcvit. could utiiu be* C'„1I„. or, hi general, 
(C,H,)„; tiio broiriiiif compound would thcu have the formala 
(C,n4Br)„. Asaumiug the formula lo bo C„H„, that of the 



DETBRMiNATlON OF MOLECULAR WEIGHT. 



U 



brnmine com]>otiiid would bti C,jII,,nr,. It in (evident tlut in this 
cace two Itydrog^i atoms would hnvo Iimd dirn;;tly repliicod by 
bromine, nnd p:(pcrim<.<nt« would Ijo mado for iUv. par|>o»c of 
obt*iniiig C,^„Br. Should these not o-ttflin the desired result, 
tho probabilily that the nirapler formnlit ('^HjHr ig correct would 
be iiicr«i«ed, aUhonf;h it would not Iju jierfoccly eetablidied, 
because it might happen that tho conditions neceesni^ to the 
fonniition of the compound t'„IJ„Hr hud not been fonnd. The 
chemical method only fiimiehns us with » proof that the molecnie 
of Itenzeue cannot be auittUer tlian that c3:pre8«od by the formula 
C,H,. It is, howeT#r, impoesiblo to daeide in this way whether it 
is a multiple of thig or not. 

In order to ueertaln the rent molecniar weight, physical 
meihoda miist lie mndenae of. These consist in the determioa- 
tion either of the specific gravity of the ooinpound in the K"<w-uur 
etate, or of certain vahieti which depeud on the oeuiotic prwtiura 
pi th« Bubstuncie iii dilute solutiou. UwUl t>e seen later that thero 
is a etose coimectiou betweeu tlieiM ajipureiiUy totally dilTorent 
muthods. 



DeterminatioD of the Molecular Weight ttttm the Vapour Density. 

11. According to AvooAlnio*s h»w ('* Inorganic Chctnielry,** 
SI, 3S, and 36). oriual volumes of ditToreut gues taeosured at the 
satuo tempenitun* ;md pressure contain the same number of mole- 
cules. From thiit it fullown that the wcighte of i\\v molecnles of 
tbeee gneee niuet stand in the same relation to one unotlier as the 
weights of these et)ual volumes. Since the atomic weight of 
hydrogen i» taicen aa unity, aud a molecule of hydrogen eontains 
two atoms, the molecndar weight of h^'drogeii is 2. Ifancquai 
volume of anotlwr p\» under the same oonditionB as to temperatUK 
and prnwire weigh a timtst as m\u:\\ jis hydroguu," then itg mole- 
cules nUo will weigh a times us much, aud the molecular weight of 
H the gtts will be 'ia. 
^^ In order to be able to calcuUte the vapour thnsity (the specific 

I gravity of the substance in the gaseous state), four i»anlitiefl— the 

I weight of sulwlanco converted into the gaseous state, the volume 

\ of the rcsnltiug vapour, the temperature' at which (he volume is 

^^L moacored, and the barometric pressure — must be known. 



'am tlivnttura itw spodOc gnrhj oj the gfta r»1»nt4 to lifdrngwo. 



ORCMNK CHHMISTRY, 



'^ 

^ 



IS. ViLpoiir density is lutuilly d«ti>nni[K>(l br u metboil sn^- 
geeted by Victok Mkyck- llie nppamtns tnK-'ussiiry fi>r tliu 

(Fig. 4-) cuiuiiDU uf H glusji itibo i 
witli an iiitttnuil (lismcUT of ultoiit 
4 mm. This hibc u cXotxA iil tin* 
top with a MAppcr, «nct Iim iin<)cr- 
iipot)) » wider crlinilrirul ]M»rtion 
-H uf nbout 200 cc, ca|Micity, rktu^d 
at the lon-cr cuil. Nuur thp top 
of thu tube in iw'alcil ou i\ <3(*liTery 
tul>o / fur the giie, wuli-h is rol- 

(■■^^^ 1ect«d orer water in ii ffradu*le4 

^^/ tube g. Tlis ftppantus iii partly 

\l surroutidetl by u niile g]a»t (or 

\^ tncdl) jiioket a. Thia foiiiains 

^ ^^ tt liquid of bif^ber builing-point 

I V^V ^'**" ^^'^^ ^^ '''^ mbetaacc wlioee 

■ ^^^ TBponr density is b«in(r dot«r- 

mined. Tbia \i<fnA in hfat«Ml to 
boiling, Home of the nir in b beiiin 
in mniiefiuence cx[icll(<d. A {toiiit 
ifi soon roMchfd whrn no more air 
escupuB from tlic drlivpry tnhe. 
that in th* wjdM ptirt of tiie tube 
hftving H ooD9tuu temperature, 
very nearly eqnal to that uf thi> 
vajKinr of the boiling liquid. Tbp 
pvdnsted tube ia now fiUed vith 
water and plaml ovt'r the opoD 
end of the delivery tube /. The 
atopper ia then witudrawn, and a 
weighed quantity of tbe subHt»n<->e 
to. t-VtcTOR Metrr'o VAFOca undpr esaiiiinauou. usually eu- 
uasMTT ApruuTPfc closed in a lilUe glass tnbe, ll 

'dmppLtl into the apparatus, anil the stopper replaced, care being 
takt<n to mukv it aiT-tight. The eabmwiM Ta|M>rises <)uickly in 
tb« heat^ wide portion of the tube. It^ v!\[tour cxpelti air from 
i\\v apparatus, wiiioh is collected in the graduated tutje, and is 
equal in vulume to that of tlie vapour itself. While, however, the 



OETERMIN^TION OF MOLECULAR It'F.IGHT. 



»5 



ftir ill fche liot purt of tUu appiiratuB buH tbe local tempeniturt-, 
in the gmdiiAtod ttthv it ikcqiiirug iho teuip«nitnro of tlio latter, go 
thikt thix nuii^t Ik* takvn iiilo uecontit in milking tlic palciilntjoii. 
The exjwriiiieiit gireK a rnluino which is <y[H!il lo that which th* 
wciglifd portion of llie mibstimco in the fon» of vapour would 
orriiipy. if it were possible to conrort it into a gas at the ordinary 
tt'iitperature anil under the linminetric presfiiire. 

For^ase of mauipuUtion thiii method Ieuv«e nothing to be de- 
sired. It pot!se«<ue&, iiioroover. iho great lulvHiiLiigo over ihu otliiT 
tiii>lhoilB, that it is not iieeustutry to know the tenijtonitnro lu wiiich 
the upimntns 1ia8 been heated, since uo n»e ii nmde of this in the 
cHlnilittiun. It is only neoeBnary thai the tempcnttnre ahotild 
reuiiiin conttfant during the ehorttiine occnpicd by the experiment. 

The result is calmlated in the following way. Suppose thiit 
g mjf. at tlie BubKtanee wern weighed onl, and yielded V e.f. of 
air, ineiuuiriMl ovor wuter. with the level the euiiit! inside and out- 
side the tube; aiippose fnrther that the bnrometno pressure ucrt) 
If, the tcmperoture /. and the tension of aqneoiis vapour h. theu. 
undiT u presAure ot II — h mm. and at t°, <j iiig. of the suhstaneo 
would occupy a volume of Tec, »o tlint under these conditions 

the unit of vohimo (1 c.c) would eontain -^ mg. of the BubsUince. 

Ono e.c. of hydrogen under ft — h mm. of prewinre, and at t', 
weighs 



0-0805 



//-A 



1 -f- 0-00M71 ^ 7iM ' 

frnni which it follows that tlie vupour donailjr D compared to 
hydrogen is 

ff 1 + 0-OU3«T( 760 



O = f .- X 



0-U890 



u~y 



The niolvcalar weight M being twice the density, 

J/=3A 

Victor Metks'8 method caTinot nx a rule be spplied to sabArances 
which decompose when boiled under n pri'ssuro of one niitio>pliei'v. 
SulMtiLiioesof thix kind cnii often Imi convened iuio v»|)oiir Without 
decomposition undor diminished preeaure. To doieraiine tht- vnpour 
density of luch itub!tin[ii.-c« DoruAXK's method innj- tw employed. 
ThU win in genoTnl iisn up in Ihe time of Viptok Mevrk's di«oov«r]r, 



l6 ORGANIC CHEMISTRY. 

but it Is now Bcldom eioployctl, as it is much more Gomi>Iicatcd thua 
Ilia Ialti>r. lu HoFM^N^'g molliwl a. w^iglivil i}uiLTititf of ttic- sub- 
stance, contained in a verj* siuall bolllo intli a si^und glass Alopi>er, 
is introduced into tbe vacuum of a baromeLrJc tul>e. dividet] into 
Ivuthsof a culjio cuutiiuctre. Tliia tube U aurruuuiJcc] with u gliuui 
jaekvt through wlilch ih jiKSsod itiv vn|Hiurnf a boiling liquid, tbe boil- 
ing-point of which is higher llinn thai of tho substance iu thf< vncinini. 
The necessary data for oaJovlaliiig ilia vapour lieusity are oblniiiocl by 
rewlinx the voliimo which the snbAtance<>ci:u[iiesin lliegaHcouKHiAii-. 
tho height »r tbe iniTvury In tho tube, lb« ntuiosphorlc pressuro, and 
tbo tompcrnturo uf the appnratus. 



Seterminatioii of the Molecular Weigbt from the Lowering of the 
Freezing-point or the Raising of the Boiling-point. 

13. In *• Inorganic ChcmiBtry" (40-43) reforonco ia wade to 
the faet that solntiong pontain<?<I in a vessel made of a eeiui-penne- 
ahle material, which BeparRtcs them from the solvent, exereise an 
osmotic presstiif; these solutione obey the lairs of Boyck auil 
ffAY-LrssAC. It in also stated that tlie nnmerical valne of the 
osmotic pressure is equal to that of the vupour pressuro. In other 
wortJs, whenever a certaiji quantity of ii mihytatiOL' in tiiv gaseoua 
Btate occn|)ieB a glveu volume, it oxercises a vajioiir pressura which 
i-i exactly etjual to the oMuotic pre^tire uliich would be ohtaiiu'd 
by (liKBolving the same weight of the substance iu a liquid and 
diluting to the c<ume volume. 

Accordiugly the law of Avogadro holds good for dilnte 
eolntiotie, for BupponJug wb liavo an equal number of mnlecnlcs 
difwolved iti i-qual vohmiofi at the sniua u^mptTaliint, tht-u we know 
from the equality uf tho vnpotir and osmotic pressiircg tliai t^aeh 
will exert an exactly identical osmotic pressure; and, inversely, 
tboTe will be Lhti eame number of molecules of the diseolved £uti- 
etatic« contained in equal volnmefi of the solvent, undor like con- 
ditions of tenii>orature and osmotic pTemure. 

Wo haro her*; a very impurlant extension of th its law. For it 
ia possible not only to compare the weights of equal volumes of 
gases at tlio same temiJurature and pressure with one another, and 
hence (o calculote the molecular weight; but we know further, that 
iu tho cNso uf eolutions at the same temperature and with the same 
oBntotto pressure, Lho weights or the BuhAtaneeit ])re»ont in equal 
volumes of the solution nre proportional to their molecular weights. 



DETF.RMtSjtTlON OF MOLECULAR UTEtGHT. 



»7 



•Tiist aa the molet'iiliir weight of gikieoua snbatiuicM is Hrrived 
at by (letfrtniiiing their teraiieratiire, pressure, wuighl, mtiJ vol- 
im>«, fto for dilute Bolwtious this is obtained by detirruiiuiug lh« 
Tolnmc uiid ttimpfrutun> of thu Bolution, together with tho r^uitn' 
tity of siihtiUiiiL-i! iIiiuluIvlhI, aud the {ijtmotir pressuTO. The molec- 
nJiir weights ot »11 ^iilMtuncen which ure Holublu in iiiiy liquid can 
ht determined in this wuy, aud mice many mere ftiihetances are 
Gotntile thiui urc ohlaiiiiihk- in thf form of lapnnr, it is now pos- 
liblo to dotcrmiiiu iIk' mwk-ciilar wcijjht vl u much grcutcr niimher 
of eompoundx th:tn wim prcviou-ily the eagf. 

There is, howevpr. a dlfiinilty of n practical nature; a direct 
determination of the oKinirtie prpraurc ik hy no niuanB o»«y. This 
woald indeed malce the method alinoHt nsetexs, if it were not 
for the fact that, in order Ut drterminn the molecnlar weight it is 
stiflicient to observe whether two seliitions have the snme »»[iiotic 
preesare. witfa<jut knowing its iibsoliue value; because A\oaADRO's 
law odIv roquir(>8 timt tho ro'.umc, tcnip(<ratiiTe, and preeetire 
(oGmtitie or gaseous) shiill ho equal, apnrt from the quoHtiou »f 
what the absolute values of tLe-8c (luaiititles iir», so long ax they do 
not exceed certain limits. It is ea«y lo measure {|u&utltius wbiob 
arc proportional to the osmotic pretisiire, and to infer from tlieee 
whether there id cqnality of oamotjc pressure or not. Thete 
quantiti<H are the hHvri»ff t>f the frettivg-^o'ini, and the raiting of 
the. boiling-point, or the differenoes between the freeziiig-jminla 
and the boiIing-poiul« resiiectivoly. before aud after tlie jtubstunoe 
liEH hueu diMolveJ, tho effect of which ia to lower the freezing- 
point, and to raise the boiling-point, of the Ailvent ("iDorguoio 
Chemistry." 42 and 43). 

14. The lowering of cho freeziog-point, and the raising of the 
boiling-point, funmh a meanii of determining whether sulntiona 
ore iivioKif-, i.e. whether they have the same osmotic preajtiire. 
The frcexing-pouit of u aiiheftance. phenol for example, ia astwr- 
taioed, and a gramme-molecule of a substance of kuown molooiilur 
weight is disaolvwi in a known weight, and hence in a known 
volume, of the Bohent. This lownm the freesting- point by a 
certain amount, wliieh is always the name for the same solvent, no 
nintter what the tnbstanre may he, provided that the volitmo of 
Mlutioii. contsining one granimc-molucuh-, la the Riime. Tliiii ia 
line to the fact that such eolutioua uru isotonic. Tho lowering of 



i8 



ORGANIC CHEMISTRY. 



the freezing-point eaiieed by a gramme-niolecule is therefore a 
constant for this solvent. If a I<^ solution of a substance of 
unknown molecular weight Mbe made in phenol, and the lower- 
ing of the freezing-point of this determined, which we will call A, 
then 

AM— Constant; 

because the lowering of the freezing-point is, between certain 
limits, proportional to the concentration. 

It is easily seen that this formula is equally applicable to the 
raising of the boiling-point. M is here the only unknown quantity, 
and may be calculated from this equation. 

Example. If phenol is used as the solreut, it has been shown by 
numerous determinations that the product of the lowering of the 
freezing-point of a 1^ solution of the substance by its molecular 
weight is equal to 75. We hare then for phenol 

AM = 76. 

In the case of a substance whose ompirical formula is C-H-K,0, the 
lowering of the freezing-point of a 2-7S!t solution of the substance in 
phenol amounted to 0-713°. In the case of a 1% solution the lowering 

would have been-rj^-Ur = 0-288; therefore A = 0-258 from which it 



8-75 
follows that the molecular weight is 



0-258 



= 391. 



Since CiH.NiO corresponds to the molecular weight 135, and that 
of CmHmN.Oi to 270, the latter comes nearest to the molecular weight 
found, so that double the empirical formula must be assigned to the 
compound. 

The constants for the lowering of the freezing-point [molecular 
lowering of ilie freezing-jwtnt) for a nitmber of solvents ore given 
in the following table : 



Solvent. 



Wiiter 

Acetic add . . 

lleiizene 

Niirolicnzene 

rliennl 

Uretlinii? 

Stearic acid. . 
p-Toluidine. . 



Moln.'UlHr LoneririK 
of the FrepE[iif(-poinl. 



19 

39 

53 

70 

75 

61-4 

45 

62-4 



lie] ting-point. 



0° 
16. 5° 

5° 
89-6° 
48.7' 
53° 
42.6' 



DETfiRMWATMN OF MOLECULAR WEIGHT. 



»9 



m 



The Itusl lour solveuti* are very uacfut, and an- better than 
glaciftl icctic aoid, which is etill often oniploycd, becniiBo ther are 
not hyproKpnpic, iinJ, having mt'lting-pnintg higher thiiii the ordi- 
nary t^mpcmtiirc, obviate the nprPBsity for a coflliug-agoiit. lu 
addition, their contitantii are high. 

Tha constnuts for the inimng of the boiling-point {tnoitcnlar 
ruiting of tht boiliuff-jioinf) arc il for 
etlier, 11*5 for ethyl alcokoi, 3(!-7 for bm- 
teiie, 'm-*> for chhrcform, eto. Thcs& 
nnmben are on the whole nitu'h eniallor 
than those for the molecular lowering of 
thw (!**]£ i II g-jwint, Tlie extent to which 
the Imiliiig-point is raiHeif \s therefore lesa 
thttu that to which the freezing-point U 
flsproMed, from which it follows that the 
latUrr detorminaliuu givvtt groater accu- 
racy. 

IS, Kykmam has constructeil an ap- 
jtarutii? by wliich tlio depreesinii of the 
freosing- point may be catiily dett^nniiied 
(Fig. 5). This coiisialH of a smsill tliiT- 
nioniHti'r divided into twvnliethH of a 
degree, to whieli la attachtNl a little tlank, 
as nhowa in Uic llgure. The whole U 
contaioi-d in a ^laB8 cylinder, is htdd at the 
top with a stopper, and enpported under- 
Qcnth on cotton wool. The ]attcr ha^^ th« 
efToet of making the cooling take plare 
more slowly, i«ince it in a bad couductur of 
beat. A weighed qutuitity of the aolrent ia placed in the fktik, 
and its frcexing-i^tint determined, Thi'ii a known weight of the 
sabntancc is iutrodui-'i-d, and the fit-czirig- point agiiin obeerved. 
Id IJUB waif a dcprcmoii of the fre-cjin(i:-poiiit is obtained, from 
whieh A may bo caleuhit«{] as in the example givon on p. 18. 




<£^^ 



Pia. S.— KraMAiVv 
DariiEeaiuBTKit. 



The lawa of otmotiD pressnra only liold good wben ihe solulioris ikr« 
ver7 dllnte. and the nnino is tru« of tlio uiiiutloD A^ = Conat., ainoa 
it b dorivw) from ih«e lawa. 

Il is uoi nlriotlj- ovrreuL to di-lerniiii» A by tupiina of a solution of 
ftnite concentration, iw was d»ii« in (lio omttaplu on p. IH. In ord«r 



ae 



ORGANIC CHEMISTHY. 



to determbie Jf acotiratety, tlie ralu« of A otiuuld b« derived from & 
Hdmion of inflDite diluMon ; hut lu ihiH H not piias:bli>, Etku^x 

liiis (Iciscribcd the fnltowiiii; graphic 

method of determifiiog A for ea«b a. 

Boliicton. A ll 

del'TTiilDnd for 

threoor fourcou- 
oiiiitrat ions, iiud 

the vaJuRs ob- 

tniiiod urn repn- 

HCIltClI ^fiphlo- 

nUv lu in Ftg. 8, 

i n nliicb t h o 
and thoao 




Fvi, A. 

valum of ^ RTc ttia ordinntes, 
of ttie i)crceiittig(;-Hlrcii|i:t.)] of Lite aolmioits 
are tbu atwoisBu:. Etkujik states tliat iii n 
vecy gmt nutn;' cases tbe lino nljiob con bo 
drawn tliroD|{h ibe tops of tlio ordinuies is 
very iienrly s. alraight one. If il is prmlucod 
(111 tt cuu the ordiniite O^i. OP^ givea tba 
vnlue of A for infinite dilution. 

For doterminiiig the niiaing «f the boU- 

tng-point, MrCoT has oonstnictcd a Yeri* oou- 
iTenient appiinxtiig. It coiwiats of two veseols, 

A and B, fitted tightly togpr.hcr. Tho iiinor 

tub© A is gradimtpd near the lower end, and 

is Joined to a narrow tube «ft, opening to the 

exterior at a. A side tulio c \nuh from the 

nioutli of vl to a condcnsor. Tho jacket B U 

on V* y>d at the bottom, and hnx a i<ido tube 

rf, cloaed by a rubber tube and piucli elamp. 

Abotil 50 c.c. of the pure solvent and a Kinall 

piece of day tila (to promolB Tegular boiling) 

ar« pUc«d in the jacket, and 12-lG c.c. of tho solvout in tho 

inner tube. The liquid iu the jacltet i» hcatctl to bojliug, 

and its vai>otir warma tho other liquid. Ae eoou us the latter 

bcconiM hot, the vapour in the jaekot foreta ila way through ab 

and raises the tcm[)eratare of the liquid in the graduated tube 
^to boiling, whereupon a slow diHlillation into the condenser takos 

place. Superhotttiug is thus avoided. The reading miiy be taken 

vithin fivo t» ten minutes from the begiuuiug of tlic operation. 




Pio. 7,— MCOOT* BotL- 

1X8- IVIINT ApPARA- 
THH. 



THE ELEMENT CARBON. 21 

On coolingi d is opened to prevent the liqaid from being aucked 
out of the graduated tube. The boiling-point of the pure liquid 
having been found, a carefully weighed portion of the Bubetance 
whose molecular weight is to be determined is introduced into A, 
the thermometer and cork being temporarily removed for tliia 
purpose. Ae Boon as the boiling-point of the solution has been 
determined, the boiling is stopped, the thermometer removed, and 
the volume of tue solution observed. The formula is tlie same as 
that given above, volume being substituted for weight, and the 
constant calculated on that basis. Eykman's graphic method 
(p. 20) of finding A for infinite dilution may he applied in this 
caae also. 



THE XLEMEKT CABBON. 

16. Carbon occurs in three allotropic forms : diamond, graphite, 
and amorphous carbon. For a description of these the reader ia 
referred to " Inorganic Chemistry," 176-179, which deals also 
with the compounds of carbon with metalloids and metals, as 
well as with the determination of its atomic weight. It will 
therefore be here sufficient to refer to certain facts regarding the 
molecvU of carbon. There is no doubt that this consists of a 
great number of atoms; how great, has not yet been ascertained. 
It is supposed that there are more atoms in the molecule of 
graphite than in that of amorphous carbon, and more in the mole- 
cule of the diamond than in that of graphite, because grapliite 
and diamond are more difficult to decompose by chemical means, 
and because their specific gravities are greater than that of amor- 
phous carbon. 

The determination of the vapour density of carbon is impossi- 
ble, owing to the high temperature necessary to convert it into tho 
state of gas. The depression of the point of solidification whicli 
carbon causes when disBolved in molten iron cannot be determined 
with sufficient accuracy, because no method ia known of measuring 
differences of temperature of one-fiftieth to one-hundredth of a 
degree at the melting-point of iron. Moreover, the phenomenon 
would be complicated by the fact that iron enters into combination 
with carbon. 



22 



ORGANIC CHEMISTRY. 



It can be shown, however, in the ^ctUowing ways that the 
number of atoms in thu nioleinilti nf [■arbon i» a largo one. When 
amnrplious ciirbnn \& oxitlizcd wilh imtueniiim jwriuHngiinste, 
mtUUi'; adtl is fortnoil, contitining twolvo Atoms of ctirbou in the 
molecule. Tlij)) iiinkc-s it to n (wrtnin extent probable Ibnt tlie 
muk-t^iilo of carbon contains at U-ii8t twelve atoms, bocaiiso wlicu 
organic compoimde a.n oxidized. siibatAiiccg are formed wliich 
ueiirly always contain eitlu^r a, smaller or the same nnmbc^r of 
carbon atoms in the niokwulo as tbe Biibstnnce whicli haii been 
Bubinitled to oxidation. For the foUovriiig i-ea«0D8, however, it 
is bolicvMl tlint the number ot atums in the molecule at cjirbon 
is greater than thin. Among the products obtained by leiuling 
marsh giis, CU,, through a heated uibe, it found ethylene fftit, 
C,n,. Whoa this i^ treated in the mme way. acetylene, t^'.U,. i» 
formed, which in ite turn yields liirnzene, C,!!,. When benzeiic- 
vapoiir is led througli a white-liot tube it forms Hup/ifhitUtte, 
C,„H, , and pt/re>if, f'„H,„, etc. On heating naphthalene or pyreno 
to a fitill higher temponilure In ahsenire ot air, carbon is pwidncod. 
From tltiH It is seen that, ax the temjierature risen, compounds are 
formed conlutning more carbon atoms in tliu molecule. This 
mnkea it probable tliat the final product of Ihceo reactioMs, curbou 
itoctf, contains a coasidenibly givutvr number of utonni in its undv- 
enic than the nuniber of enrbon atomfi in the molecule of pyrciie. 

A thirJ l^roof of the greiit number of hUiiiir in the molecule of 
cnrbon is found by examining the bnitiiig>pointtt of its hydrogen 
eom^wunilA. If thcw be dunotcj by the general fornnilu ('„lI-.„_^, 
then, even when a and ;) are betli large numbcre, the boiling- 
points of theee substunucs are reUlivi-ly low, and rise with the 
increase of both m and ;). For carbon itwlf, '2n — ;j, and, on 
account of the extmordinnrr non-rolatilily of this subetunce, tlie 
ralue of n mu«t be rery great. 



y/tUNCY OF CAR60N. 



»3 



VALEKCY. 

17. T1i« fttoniK of Bom» olemcnU bavo the property of being 
iinablp to combine with more than nne atom of uny other elemttnt. 
The halogens on the one )innd, and hydrogpn on 
ih« other, yield only compounds of the type 11.X, 
in wliifh X stands for tli*i hiilogpn «tom. Tlila 
pTopenv i<; L-idlinl moniMHihttcy. 

Of other elements, for oiamplo those of the 
oxygen groiiii (O, S, Si\ Te), one atom \i able to 
combine wiili iwo monuraleni nloniR. Such ole- 
nicnts are therefore called divalent. 

The nnmbor of uloms «f n iiionovslont dement 
which (Tin ntiilo wiih oiiu atom of miotliur «IeuiL>i]L 
Lhvrefore iter^'e lu a measure uf the Utter's valency. 
Thus nitrogen coiiihiiies nitli three atoinsuf hy- 
dru^en. and ia iht^refore Irivitk'nl. Hut the com- 
]>ouBd NH, can still unite with HCI to form J 
NHjClj in which there are five rHonovalect iitomii 
att4i(?fai'd to one iiiirogen iitom^ ^o tlutt iiiLrnj^eu 
cmn vAm he jientavaUnt. Many 
clcmenta besides nitrogen hare 
morc! than one degree of va- 
lenuy. 

Carbon forms with mono- 
vulent elements (.-unijioiinds of 
the type CX,. It in iherf/ore 
tetravaltHt, anil if is on ffiis 

/oMHilatiOH that the wfiair sitfvr- 

structure of organic ch^nistry 

restn. 

The compoiiiiJ CO. ia also 
an inBl»uce of liic tctravalciii:)' p,o § _ Hkatiko Fio. 9. - Fi-ask 
of eorbon. In ciirboii mun- Schstaiccesis as with IIk.fi. ux- 
oxide, CO. ou tlio oilier l.aiKl. "''kk Flask. tosuKNsuK. 

the oarlxm aloiii must be looked »\»>\i :w divalpiit. at Iwwt if the 
dlTiHlencyof oxyguti iit reUiued. OlhC'r compaiintlfl »ro well known in 
-wliich eArtwn rn^y bn looked upna asdivaleiit, but tbeir number U 
Ter>' xuiall in comparbeD with tboae, niimb^ring maDy thousauds, in 
yth'toh carbon mUKt be regardt-d il» teiravalenU 




tCMMC CHEMISTRY. 

LABOBATORY MITH0D8. 

IS. Refore wo prot**-*! with the <I^(u?riptioQ o( the organic 
compoundK, it i.<i ^ipjiiralile. to preTcnt FO{>etitiou, to gire a sboit 
ncoount of the mnBt important pruceesm osed in their prepunitioa 
and inTfttigution. 

ileatifig Subs(a»e<» To^flhtr. — Thia procoss is rorj- oftou used 
with tho object of inducing rvActiou between bodies, su>c« the 
vol(H>itT of rifMctioiig iiion')u«-« largt'lj vith rise of toDipenilnro 
(" Inorgmiir Cheniuttrir." 13 ami 104). The procww varies acrord- 
iii£' to the leiDpcratiire to which tbvv muet he heiUixl. If thU is 
ConaiJeniMy In-low the boUing-])oiiit of themoiit volatile compoumJ, 
the; are hiu{<)v mixed together iu a Uaek Httvxl with a thermom- 
eter, as in Fig. K The fliuth la immoriied in n bath of liqaid, 
whIlt, oil, or molten Iwid, HasK's alloy or other metal, etc., being 
UMLtl fur lluM purpose. Should, however, the brjiliiig-point of one 
of the lubitanvea be ruached or ovGr.>tt4>ppeiI, then the fla«lc imut 
be roiiuwrtcd with a c-ondcnecr, as in Fig. 9. 'flip invention of 
liki< form of coudcnaiug-upparatux is nfitmlly attributed to LiEBIOt 
iilthou^h it was firet conrtnictwl by Weigel in 1771. It conaisto 
of n ^liuw tithe n/i, enclosed in a jacket of gliuu or metal i, through 
which a Ktn^iim of cold wul4^ir can pHas. If the Hubulance ha^ a 
high boiling-{)oiQt, it is anfflcient to connect a loug gtau lulw to 




Tt9. 10.— thsTILLATlOM .llTABATPe. 

iha flask; tho air keeps this sufliciently coo), so that a tube of thia 
kind is oilleii an air-frmdenser. The effect of this condenser is 
CHRily understood, the boiling lirpiid boing onndt-^nfieil in it and 
drop]iing hack again Into the flask. When it is doommij to 




DISTILLATION IN k'ACUUM, 



'i 



heat Bnbslwnoea nbore their boiling-pnint«, ther aro pLiced in a 
fhk'k-wiilted giants tiibo eeiUed at one end, which is th«n Kefticd at 
the other, &nd heuted in a tube (uraoce (Fig. 3, pnge 0). 

19. JJhliilalioH.—Tor' this jmrpoeo the apiiarBtufl flhown in 
Fig. 10 ia ueeii. If, however, tho 
Itfjoiil to be di8tini<(l is of euch 
Ik iiiiicrv tliikt it wuutd becomo 
ountaiQ iiifttcd by the action of its 
TRpoiir on th« cork or rubber 
Btoppor Bhowii in tho figure, a 
di8til1iug<11»8k (Fig. 11) k sub* 
etituCed for the ordinary one. and, 
if its oeck be sufflciently long, 
allowa the pnbatanc* to be dis- 
tiUed without comiag in contact 
vith iho stopper. 

20. Many Bubstances dBcom- 
po&i' when heated at th« onliuary 
prosaire to their boiling- poiutu, 
bot diittil unchanged uudvr di- 
mintsbcti pressure, because the boiling-point in then much lower. 




KlO. II. — FnACTIOMATnTA-rl^SE. 




Fl8. la — DlBTH-LATIOSI IH VaCTTOK- 

"T*bo apporatuB shown in Fig. 12 may be used for mcuum di»- 
tUlatioa. 



36 



OKG^WC CHEMISTRY. 



'i'ho lif^iiid o-hich is to be distilled in placed in ri. A glagit tnbe 
e, flmwn out to n very fiii(> p>nint, dip^ into the liquid, und n tlicr- 
inoineti?r Ik placed iimidc thi8 Cube. As soon a^ the appamtUH has 
been mack Tacumia by tbe WBttT-pump w, a stream of smn]) bub- 
bles of air t)8c;apo3 from the very fine point of tlie tube e. This is 
to prevent the violont " bumping" which occurs when liquids arc 
l)oiled uiidor diminifihed prossiiro, cmisod by the audden and inter- 
iiiiltent formntion of vapour, whereby boiling-ovor somotimes 




FlO. 13. — FK*mO)*ATI!*G-COLfM!t8. 

Mcan. or tho flaak is broken. The rccoiTer I is kept cool by a 
atream of water from c; m is a mercury manometer: a a two>Tay 
stop-cock which pormirs access of air to tho upparatiis after tbi- 
diiitillation, aiid at llic same time serves to cut off the codDectiou 
betweeu the air-pump and the rest of the apparatus when tbe 
pump "etriketi harrk "; that is, when tho water rises through tbe 
tube * into the apparatus. 



FR^CTIOKAL OSSTILUTION. 



«7 



31. Tlie »ep4irntiou of a mixtare of Tolatilo satjetADCve iti effected 
\>y fractional dietilMion. If a mixtare of two lifjiiidB, boiliiig &ay 
at loo°uiid at i:ur, h <]iBliUt»tl, tliit oiio tijal Iwik at 100" will 
distil over priiici^nilly at ihv 1i«ptintug. and the ono wliidi boils 
at 130'' at the end vt ihu o[K<ratitiii. If what juutsea over before 
the thfnnoint'UT renchi-a 110' is coUcL-teJ »cpiinit«ly in ciiio frac- 
tion, anil ttiruilarly vhttt \nigsm over hetweeu 120" aiid VK", a 
ronxh scpnrtitiou has alren<ly been effc^tcil, vhilc the middli) 
fraction utill <!oiiaiii(ii nf a mixture. Tu iiuike the scptinition ns 
ctTnplctc :iH poKsiblc, the fraction 100''-110'' is pnt back into tbo 
fmrtionating- flask anil diKlilloJ over til) thn t Iiermnnietor renchos 
IIO", Iho frac-tiun llO'-l'^i''" buug now mixed with the residne in 
iho frautioiuitiu{:-flMk. The dietUlation ia then continned till ihe 
thermomftvr again stand g at IHV. Another receiver is now em- 
ployed, ami t]i4> dislillation r^ontinnei! till tho tht^rmomctcr reaches 
130*. ^Vhen tlijg is the rnse. the fraotion ISO^-tSO" ib added, but 
the receiTer is only changpil when the thermometer again iiidicut<a 
120". The portion which ilistils after this in collected sepurati-ly. 
By repeating this pro<:c«i wvoral time*, during which it is usually 
desimhle to collect the fraetions helwcen narrower limitd of tvm- 
perataro. and thus to iiu-rcii^o their mimber, it is poaeibl© iu juauy 
usee to effect an almost complete eepiration. 

Thin Bepanition is greatly facilitated by using a fractionaling- 
coltiQin (Fig, IH). which in connected to the nt-ck of the boiling- 
Qttnk. and haa the effect of condeneing the lenet volatile ]iart of the 
va)>our. Thie Li attained by tncreafiing the cooling-surfacrn hy 
meant) of hullw, or by ]»iitl.ing obst met ions, Huch &s platinum 
gniizo or glass Iwads, in tho way of the vapour. 

IS. A mixiiiryi of liqiiifU cannot always bo flep&ratod by fr&ctional 
dbtilUtinii. Whetlicr tbU is possible or not, dcpentla on tbo following 
enntideraiitiiiB. If two liquiUs with different vaitour tenuohH nro 
misml to Htich a way lUat a Rmall quAtilily of llio unc is continually 
n'ldi-il to the nllior. It t« often (ounil Itint itiv vnpnur (ension of ihia 
tnisture. itte ic»i)<fnitur<; ri'maiiiiii^ itio sutnc, riBcs or fiilt«c»iitinu> 
ally, lilt anility, wlicn u great excewi of ilie secuml Uquid Iina bevn 
adile<l, lIiD rapoiir tension of tlio latter ia rnry nearly reoi-lied. Tlils 
Lt gmphtcally represonied by the line AB m Pig. U The rnpour 
teoaions of tlie nuxtur«a all lio betwecm tliOM^nf the two {Him sub* 
aUnouK. wliieh enn^illiiiR Die ninxiiiiiiin H ittiil mininnmi .1 for tho 
whole series. In aoiua caaea, liowcver, it baa twcn sliowii tbxL in Hit* 



«8 



ORCMMC CHEMISTRY. 



wn; A mixture n oblaitMd wtiose TApour tetuion is a maxitDnin 
{f\g. IS) or a miQimam (PJi. 19). It is tb«n inpoenble lo effect mjh 
aratlon b;^ fnctlooAtiog, us ma}* bn seen in the tollowing iraj. Tb* 
most TolntilQ portioa nf a liqaid idwajs dUtils Snt, and itt tho cose of 
a mixture witJi a maximum vapoar teuKiou, this is itio must rulaiilo 
ponton o( an nrbitrnrr uizture of the two liquids. On ihb acooinit 
there wilt be flniUly oblHinc<l a Trnction luiviiig tbe eompoaiUoii of lh« 
mixlure with maximum vapour tvnsiou ; which of the tiro stib«UDcM 
will be obtained in tbe iiiiro Ktnta will deiwiid ii{)on wbioh of tbe» 
WM pneeat ia graator proportion in tbo origioaJ, not in the Anal, 
mixture. 

If there «xiala a uixtars cf two liquids with m i Q i mpm vapoar ten- 
sion, this is llie iMSt voUltle part of thellquid, and it will be obtained 
as the final residue after tliu diet illation. Wliichof tbe two sabslauoos 
oaa be obtained pore from tbe mixture will sgaio depead, as bvfocs, 




rts. i«. 



Fig. 15. 



Pio. 16. 



OD the ratio of the quaatities of the two liquids vbJcb were originaDy 
present. 

Tbe aoporation of a mixture of liquids hy fractiouatioa is also ii»> 
possible when the boiling-fwtala of its coiulitiiuitts are close togi'tber. 
beoause the essential cbaraelerislic of the wholi- method consists ia 
the unequal volatiliiy of tbe portions of which the mixture is madaupy 
In conset^uetice of whiob one sulwlAnco di»lils oTi>r before the olhfr. 
If, howvvvT, the substanoea bare about iho same boiling-point, then 
thcjr both attain to a vapour tension of one atmosphere at almost tbe 
same temperature, being, in other words, almost eqaally volatile. It 
is therefore impossible under these conditions to apply the method 
tnoceasfullr. 

23. ^feam Distillation. — In tlw iirepanttinn of many organic 
nibstancee a cmdo roaction-prodnct is oft«n obtainc<] containing' 
tarry or pitch-like iiiattt-T nlong wilili the rKtiiiirwl (rumpounrl. In 
order to free the sub&tance from this, neo is often very advaa- 



ST£^M DISTtLl^TlON. 



39 



Idy mado oi the property possessed by manj sobstniirefl of 
distilling i» n carrcnt of Hteani, l!i« turry matturs rptnuJDiug 
behind. Fig. l* bIiows the nietlnxJ liv which such r distilUtion 
is ciirriud out. 

Water is boilotl iu tbo can a, 'ftliich is fitteil with & delivery 
tube (* Dud A safety tnbo b, the evulved at«QU) b«>iug p«Bs«d iuio the 




Fra. IT.— Steam DisTrt-LATioN. 

bottom of the distill ing-ilask d. Jf the diHtillntion Is intomiptedf 
cooliii^ CBUfioa dimiQi«h<td presMuro jn a, uir Itcing then »h]e to 
enter the tnhe b. It b wvro not u»ed, the Uqtild in d would flow 
book into it, owing to tho fnll in tho etotiin prcfisiiiv. 

Stf>iim diiitillHtion is nl-in of Kervioo in ^cpninting oompoLindSf 
somo of whirh an? Yob-tile with eteiuii and othcTs not. Iu ihe 
case of substances vrhich are insoluble in wat«r, the distillate is a, 
milky liqnid, bm-aiiso tho wutt-r which has dietillod over in mixed 

with fine, oily drc-ps, thpre being at tho «ini0 time au oily layer 

aboTo or beneath tho wator. 

"Wh^n distiHing wilh stoftin, tb* |)ressur«»f lUo miiluro of v^iwun 
must be cqiiitl to iliat of ilie barometer, niiice ibv lltjiikl is boiling. 
Tl)« boiling-poinl tnuat bo loner thnn that of thu low-pr-lmiling of th» 
two 5 II tut I an CCS under ordiijary iiressun.-. iM-cnuflrt the partiHl preaiare 
is Tjeceasarilr ftmnllnr than llic tuiiil one, whioli is ei\n!i\ to the Atiao«> 
pfa«rlc pressure'. TLi; eamo rcanlt U Ibercforo olHairied an wtieti dis* 



30 



ORCANtC CHEMISTRY. 



tilllnic nnder cllmlnislied prmturv. vix., tli« TolittillMtiun of tb« %\io- 
elstiGoat B touponituro low«r tban its boUiug-point under onlinwf 
prtesuro. 

Whether a substAuce dblils quickly ur slowly writb tteuiu, depeuds 
on lu partial ]trnitj>un< and on its vupour d«n*)ty, togetaer nith tlio 
vaIu«s v( thv^c physiciil coustaata for water. [[ tho prcuurvd are p, 
nnd pt, xnd the vnpour deusUieft (/> mid d,, the qtuiulili«s which 
distil over &iuiull*iieoiuly are ptd\ (aubalaiice), iiud ptd^ (water), If 
the ratio p^d^ : ptiU U largo, thosubttan&e dl»tilit over with a araall 
quantity of vatcr, the dislillnlion Wing quickly carriix! out ; tlie re- 
verse Uiiim pliici! wheu ihH ratio p.iii : p^il* is small. 

24. Separation nf Tim />/imisrifjle AiV/Mirfji.— A KeparntilUf- 
fuiinel is uwil for this piirptMu (Fig. ]S); the nietli<Mi tif using 
it inuy be inferrcJ from t}ic ilruwinjr without further 
cxpluiuttioii. It ix uleo rtuployiHl for i\ie exi rari n^n 
of tH|UCuu8 solutions. Tbi? iii|ttcoui soliitiou of a sub- 
8taiirQ »ohibIe in n volatile liquid nut miscilde witli 
*'iitpr, Btich HB rlftfi\. pftrniftntt-fthfir, chlaroform, 
airhon bisuiplndf, ia irHnfifcrri-d to ii si>|)aratiiig- 
fuiiiirl; ether, if tlmtia the solvent iit-lecrt«d, iiiudilud, 
ami uftcr tht ttioiith i)f llie fiimii'l liim bwii cIommI 
by M glaB» stdppor, tlic two li(|iiid» ore luixvd toKctlifr 
by vigorous abnking, whon tho auhjttnnoe whirb i* 
di880lvi>d in water pacsoi; piirtly into the elbor. 'I'lio 
ethereal unlntion in allowed tn rise to thf> top, nnd 
8«paraled from the vatcr by opniiin; tlic stop-ciock 

»ATiKO-ncM- *'*■*''' '■*''"**^*' ^f *''" Btoppor. The watur whiL-li haa 
SBL. die«ohv!d in tho ctbordunTif;thc£lmkti:ig, ie rc-morod 

by chloride of calcium, or wmo other drTp-ing-agcnt, niid. finnlly the 
eth(>r ia distilled ofif. Tho extraction is coniplotoii qiiioklr «'h«n 
tho dissolved BuUittADce is only slightly eohible in watt-r, and (•mdly 
ftolublv hi I'ther: it is then poHsible to nlmost wholly exiiaoet the 
aqueous »olutiun by ivpealin^ the opurtition a few times with fresh 
ether. OtJiwrwise, the shaking miut be repeatedly earned oat, 
and even then the extraction is imperfect, 

Wlicn two iiDinisctblcBolvfltit^ arc simiiltam^oDsly in contact with 
a Rnbilance vrbivti is soluble in Imth, tlii> lattirr dislribuieK itself in 
flitoli a way tliat llii: ratio of the ooiicoal rations reached in both 
Mlvenls Is coiitttant (law of RKRTHDjrr). If n <jiiB.iitity J', of th« 
substanca is disat>lTcd in a qiiaulity I at tbo first soivcal iwaier), and 
tills soinlion is s)ialceu up with ii quautity m of the second solrent 





HLTR^TION. 



3> 



<eitt«r). xhtfw will then miiNiti » qiuDtitj X. in the lint soluiioii. to 
thiit .r. — J', liM jhukU mlo Ihe »9Coud 8olv«iit. 

The viiluti of llio quBiilJty A'> !>. in a(!oortl>Doe with tbe nbovo Uv, 
given by tbo vquatiou 

-r. = .r. ^' 






m + 



^i* 



A7 \. 



for t' luid ^' iiro the two concoturatiiina aftirr tlic tolvsotx 

I Nt 

bavo beoii ftliiUcvn iij), nnil JT is ibe number oxpKutng t)i« eomiftnl 
rmtio, orthecvc^Mmf Q^f/MrJbuJ^ti (.Qennaii, Ttilunu^toiffitiefa}. 

A Bwond extraottoii with the ftnino quAiiLity m of tfaa seeond 
aolraiit Rivn 

.r. ^ J. - jr. 

or, aubMltntJng ih« vnln* of A', fmoi ih« flnt «qtiiitl»n, 

-■=-'--(^,)' 

and (oi llta rdb rstTKction, 

TtiuH .v., xhti qimaliiy rouixinltig in the flnt solvent (walerX 
dlrolaiahcs m n incrvnavs, ftad u m mid A' are reipectivoly KKHler 
ficd les. ComplfU cii.rACllon is imposaible. becniiNo »ltbougb 

^-^,1 can approach Mro very closely, 

it CiUi a«ver Ltecomv eijuAl lo tl. 

It coil bo further nUowh from this equti- 
tioD by tbv iisu of lltu ililTn-oiitial ciilciilue 
that with II givL'H qilHiitily or Oio i^rcoiLd 
solvent (ether) n more cuiupleii^ sepiimtion 
Ifl utTcclod by extritctiiif; frequently with 
Hniall (|iiuntili(» than by uftin^ Urgt'r qiiau- 
tiUpK M uorr««[>on<] in]{ly fewer number of 

Separation of HolUh anil Liqmda, — 
Tti* is effected by filiration. vhir:Ii can 
b« materially at^releniit"! u\ fitting the 
ftinni?!, by inaiiis of h rubhtT 9(ojn)er, iii 
SL fbtok a (Fig. 19). which h coiiiiufiiHl 
lUrouj^h // lo a watiT nir-puuip. To iirt-vont niptiire of the poinc 
oi thd filter- {Ml per, it miiat then be suiiportcd by a hollow platinum 
con«» A 




l» — J'll-TJIRINO 




3» 



OKGAStC CHEMISTRY. 



25. SfpamtioH of Solitfji/rvm one Another. — This uaiiaUy de- 
pemla nu rliffi-renec £n soluliility. If there nro two substauova, one 
Kilti'ble nnd the other nuohible, the opemtion is very gimjile. It 
both i!uhetnin-C8 arc Bi>luhlc. tho nifthoii of fracfionai er^tttdlita- 
tiou must he used. Thv mixture is diBsolrticI in the leiut pu»iblo 
(quantity of a hoiling ]ix|iiUI, mid s)lou-«d to fool, Thp more 
iiiftoliitilo ^uhntttiice crvHtiitliKea oiit first. The nnother-liqtior in 
poured off before crvfeUiIa of tho second body be^In lo sepanite, 
nnd tlie Bocond compouni:! is crretalhsi-d cither by further roalinje 
or by conccutrftting the li<iui<l by t'Vdporation. Oii n-pi^tiug thvae 
Qporatioiiii several tiineA, the Buhstances are obtained s^pflmted 
from ontt iiuother. The Kepuratioii of substanciis in thia way ie 
enmetimBB very difficult, even if thero is h very great difference of 
■ohihiltty between tho pure compuuDdn, boniiiac tho soluhiHty of 
one mibetttncw may be very considerably modified by the presence 
of anothiT. Wnter, alcotiol, ether, ;;laciul acetic acid, bcnzi-uc, 
and othpr subalancoa art* used iia solvents. 

26. It is seen from the foregoing how substanees may bo 
obtained in the pure slate: aolid iubstances are usually purified by 

cryaliLlliEation^ ami liquids by distillation. An in- 
ilicalioH of purity is that the physical constants re* 
main unchanged after the sohstanca has been purified 
anow. Although every ph^xiL-al eonstaiit onnid ser\'0 
this purpose, the viddn^'point ami the fmiling' 
jmittt art! tbost- most used, btcuusc they are easily 
dcteniiinud. and eli^ht impiiritius cxcri'ide ii very 
material influence upon theuL. They nrv al»o often 
a means of identifying snh.'rtancGS. .Should a com- 
pound, supposed to be one already known, liavo i:)oon 
obtained by iuaie p^o^^ess, it is strong endenre in 
favour of the supposition if the melting-point and 
butliiig-poiut of thu eubtitauee coincide with those of 
the compound with ^vhich it u supposed lu bi- iJen- 
Fto SO —nu- *'*"'■ f*»tftrminalionB of melting-points nnd boiling- 
TKiiaiNATioN points affl for this mason very often airried out. 

To (letermiue the viplfiuff-poiiit, tiie siihstiinno i« 
placed in u narrow thin-walled small tube ^eslerl at 
one end (Fig. 20), this tube ia alUichrd to u thennometcr /. (he 
bulb of which dips into u liquid of high builiog-pomt, such as con- 



U 




OrTHE.XIHLT- 
ISO- FOIST. 



sPBcI^tc c/wwrr. 



33 



Ited mlplinric acid or liquid jtaraffln (38). iho visooaity o( 
^Sfidl caiiaes the fimull tube t-o adhere to the thermometer. The 
tube ale, in vhich the hulb of tho thermomclor amd tbo littlo labe 
arc idacfd.itt loosely ttxcd in a small roiiQd glnas flask ar/c, cntitnin* 
ing the Hame liquid at: the tube ak. When ade \s. heated, the con- 
teut« ot the tube ale aro waniieil imiforiuly, and the moment of 
fusion of the Huht^tunce. at whii^h the thermometer is road, cnn he 
Twy accunitclj ohsejred. 

The boilivff-pinnl is determined by heating the liquid to bniU 
in<; in a fractionntinif-fiii^k with a iiigli sido tube. Short thcr- 
mometerg are need, 30 that the whole of the mercury column is 
snrrunnded by the v»pour of the boiling liquid. In order to 
avoid iii<;onT«nifintIr .tmall gradual ions, ihpse therincmoters BTOr 
coniitnictcd so rliat they can only ho employed fora comparatively 
aroall range of iL-mperatuTc, six or seven different inatnimcnta 
being used for temperatures between 0'' and 360°. 

S7. fiometinm ntli«r ptiytiical confttanta beaides the meltlng-polowi 
mill boiliiig-pnjnta are dotdrmiiied in the inroctigatiou nt nrf^n'tt eoui-i 
iwuuds. I. Tim tjMi/U: ijrmnln can \» de- 
tormioed with tlio pyknnmrUr, the moitt 
useful form of tvhicli is eliown in Pig. 31. 
It oonsists of two thiok-walli^d cafiillBrieH 
alt aud cc/| whtuh termiiiale in a widor 
tube he. The pans aa and dd are tur- 
nisbed with n itiilliiiivtrt; »CAle The cajia- 
cilT' of Ibo apparatus it ftrst dPierniinod. 
as well as of the space bolwoco two divi- 
sions, by fllliog it several limes up to 
different diTisiona wilh nater of knonn 
temparaiure, and tlion weigbing. The 

liquid wtioec siwciflu grnvit; is to b« dotonsiiied b then placed in 
the apiArnluK. wtircli is neighed ;tfrer tliu positions nf the menisci 
ia the cnpillaries have b«vu obisorvcd: from this tbe required number 
may be calculated. 

2. Tbe rotation of the plane of polaHiaUon is auolher oottatAiit of 
IraimrlanM). 

t^mo subfllanccs, sncli as tnrpMitino, a solution of sugar, ete,, 
lutre tbe projierty of jntaUng the plniie of a rn; nf pularized ligbtj 
which is passing through Ilium out of iU original position. This 
pbeoooienon is called the rotation qf the plant q/ pulotisntttm. 
aud substances whieh poeseu this property are said l» be vi'li 
aiilft active, f^larimelerx tmve beeu oonstnicUHt for niunsiirtTig the 




FlO. SI. — I'VKNOMRTKK. 



34 



OkCANtC CHEMISTRY. 



»af^K through which tbe pikne of ix>l&rir,at inn han l>een mlaivtl l»y 
nn ojiiicitlly active scibiitBnci! ; of these I.ArREJCr's iFif;. 22) m oiifi 
of tilt XwtX, known. TItr vfllow Kniliiiiii li^ht nf (be burner 7T is 
poliiriuid in the \Mri of Uio »|ijj)intliiK tnnrkeil BD. nud llion passes 
throui;li n ttibe placed in ihe channel /•, llie leogth »f which is acou- 
rait'ly Icnown (200-500 mm.), t'otuaininj Kte litjuid or aoluiion whoMi 
optical aciiviiy in to Ui itcleriiilmMl; llii; prtrl. OU nt tlm ajijiatnlus 
terves lA ti)i>ii&iiru (ho ralaltnn nf ihti pliiiio »r [lohirltaiion. 

Tliu cxicut \'> which tho plane of polHri%niioii is r«tatei3 is propor- 
ttoDftt to the length of the tuba, a»(] is exivroBsuil iu diffeKUE ways. 
Tba TOtAtioa of a subcianco is czprasMil, f>>r L-xample, iu terms of the 




I » 



■: 1 - r(ii..v f 



effect producc^l \>j a giwii l«iigth of the tuba nbovo r«ferro(J to; ihi» 
is the angle which is read off directly from ihe iiistnimeul, II U 
usually denoted hy a. By cniivpinion, the njivri/ir rulMorg jtower 
U defined as Itiv quolii^tit obtaineil hy dividing 't by the product of 
ttae lODgth of tho (ulio into the Rpecitic gratity of the htinid. This 
value 1» donotod by [a], bd thai 



[a] = 



U 



where I U tlie length of the tube, and d ]s ibe specific (Cravitjr of lb* 
liqniii. I'ndor these couditians [«] ciprcisim the rotatory jM^ver »( a 
Bubstaiiee[Xirunit Icnglliof the tnhull deuiiiii'll'u), and rni-iinit W«tght 
of tbo Hubstance divided into iIk unit vf voLuiac. 

TIte pxu-nt of ihe rotitiion is de(iendi<nt on tbo coloar of the U|fhl. 
Id niany cases the muaaur«ut«nt is carried out with sodium light. 



CLASSIFICATION OF ORGANIC CHEMISTRY. 35 

wliicL gives a yellow line in the spectroscope, denoted by D. This is 
expressed by the symbol [ajn. 

When the rotatory power ol a substance is small, or when, on 
accoDQt of its slight solubility, it can only be obtained in dilute solu- 
tion, the rotation can be increased in many cases by adding a solu- 
tion of boracic ncid, molybdic acid, uranium salts, etc. The cause of 
this phenomenon is not fully understood. 

It is often important to dclermiae other constants, such as the 
index of re/raction, the molecular electric coiiductivity, and the heat 
lif combustion. 

CLASSIFICATION OF OROANIC CHEHISTRY. 

28. It is UBunl to arrange tho extraordinnrily great number of 
organic compounds in two main divisions. One of these includes 
ih.Q fatty or alijikatic compounds, and the other the aromatic com- 
pounds. The first of these owes its name to the fact that the 
animal and vegetable fats belong to it; the second, to its containing 
many compounds, among the first to be discovered in this division, 
characterized by an. agreeable smell or aroma. 

The fatty compounds and the aromatic compounds are re- 
garded as being derived from methane, CH,, and benzene, Cgll^, 
or compounds related to it, respectively. 

It will be shown later that there are important differences 
between the general properties of these two classes of compounds. 



FIRST PART. 
THE FATTY COMPOUNDS. 

SATU&ATED HTBROCAItBOirB. 

29. The fatty compoundB arc defined iu 28 aa those which may 
he regarded as derived from methtme, CII,. It is therefore advie- 
ahle to begin tlie study of tliese coniponnils with this hydrocarbon. 

Methane occurs in nature in the gaet-s oYolve<l from volcanoea; 
it escapes in coal-mines during the working of the coal-seams, and 
is called fire-damp by tlie miners. It ia also called marsh gas, 
because it is preaent in the guaes, duo to decay of vegetable matter, 
which rise out of marshes. It is an important constituent of coal- 
gas, in which it is present to the extent of 30-40,^. 

It can be prepared in diiferent ways. 

1. (rt) By Bertiielot's syntheeis. A mixture of. H,S and CS, 
ia led over red-hot copper contained in a tube, when the following 
reaction occurs: 

2II,S + CS, -f 4Cu = 4Cu.S + CH,. 

{h) By Sabatiee and Se.vderens' synthesis. When a mixture 
of hydrogen and carbon monoxide is passed over' reduced nickel 
at 20O°-25O°, methane is formed : 

CO + .^11, = CII, + 11,0. 
The nickel undergoes no apparent change, and can be used re- 
jH-ntedly. At a temperature of aaO'-^JOO", carbon dioxide reacts 
i<imilurly with hydrogen in presence of finely-divided nickel: 

CO, + 411, = C'ir, + 2ir,o. 

Reduced cobalt has a similar action, but requires a somewhat 
higher tomjierature. Since CS,, H,S, CO, and CO, can be obtained 
l)y direct synthesis from their elements, these reactions furnish 
methods of preparing methane aynthetically. 

36 



SATURATED HYDROCARBONS. 37 

2. By acting on the compound CH,I, methyl iodide, with 
nabcent hydrogen : 

CHJ + 2H = HI + CH,. 

Nascent liydrogen can be obtained in different naye: from Bodium 
amalgam and water, from zinc and bydroctiloric acid, or by bringing 
zinc which has been immerBed in a dilute solution of copper Buiphate, 
to coat it with a layer of copiwr, into contact with water. By tlie last 
method, which was dincovercd by Gladstone and Tribe, hydrogen is 
evolved at the ordinary temperaturo in a form in which it is able to 
convert methyl iodide into methane. 

Methyl iodide can also be reduced to methane by hydriodio 
acid: 

CH,I + HI = CH, + I,. 
To effect this a concentrated aqueous solution of hydriodic acid 
is heated with methyl iodide. 

The iodide formed is converted back again into HI by the addition 
of amorphous phosphorus. The hydriodic acid is regenerated : 

P + I. + 3H,0 = H^PO, + 3HI ; 
and is available to effect further reduction. 

3. By decomnpsing zinc-methyl, ZuC,H, (82), with water: 

zS^Sw-^^^fi = Zn(On), + 2CH,. 

4. By heating sodium acetate with barium hydrate: 

CH.COONa + ba*OH = baNaCO, + CH,. 
30. Physical and Chemical Properties. — Methane is an odonr- f fT 
less and colourless gas of sp. gr. 0-559 (air = 1), lique^ng at 11° """^Tv'i 
and 180 atmospheres. It boiU at — 102°, ahd solidifies at — 186°. 
It is only slightly soluble in water, but more bo in alcohol. It is 
decomposed intd carbon and hydrogen by the sparks of an induc- 
tion coil, or in the electric arc. Oxidizing-substauces, such as 
nitric and chromic acids, do not attack it, or only very slightly, 
while concentrated sulphuric acid and strong alkalis hare no 
action upon it. It bums with an almost non-luminoua fiame. 
When mixed with air or oxygen it forms a violently explosive 
mixtnre, the reaction being in accordance with the equation 

\ CH, + 20, = CO, + 2H,0. 

This Bo-called " fire-damp "ia the cause of the explosions which 

*ba = iBa. 



JS 



;^A;C CffhMlSTRY. 



StimcLimeK cxhtiit in mat niiiieR. {!lilorim> nrid brnrniiip rcnnt irirh 
mclbaiip, tlif hrdrogen atoms of the latter Iwing rpplactxl 
liulogcn utunis, and u huioid arid formnd : 

CH,+ 2G1 - CllJL'l -f IK'I. , .J 

The rcplnccmcnt of one nt^m bv nnothcr is callwl fitmhtutian. 
If chlnriiin tir bmmine in prdsmit in ejcrpsg, thfi tiiial prfxhiot ia 
CCl, orCBr,. " 

31. Thero prints n RRrics* of hjdi*orarhnns, the general rheniit* 
jinijierlieH uf whudi »rc idi'ntioJ with Ihost; nf nietliitne. KxampU-H 
c»f thcHH compounds are etkam C!,II,, prapiine *\U,, butane C,I[,„, 
frntfu'ie i'j,H„. Jifxaif t',U„( i'tc, jmitair'utcunlinte C^II,., and 
hexttcoHUtht (^'„n,j,. These formiilie «m be mimnied up in the 
gon«rftl exproasion C„H^^, ; for metliaue, » = 1. Those liyriro- 
cartiuus i^an ht> pri'parL'd hy the iiiothodH dM^^urilxtd in 3. 3. jiiit] 4. 
It should bu obsiTvwd. liowt-vtr, tluiL bj- monng of the zinc com- 
pouriila only the lower tncinb«r)i, tho^c (.■outiiitiiug n omall iitim- 
ber of carlioii Htom^, arc obtuii)«d, bi-cau8c the higher ziuc deriva- 
tJTcs »ro not known. The hydrocarbons C„H,„., rceeinWeniethatio 
in ihuir |«iwer iif resiBtinjf oxidation, and »re utnieted on by coti- 
epniratwl »utp)iiirio acid, while h»logeiifl n-act with lliem with 
Mibstitultaii of hydrogen and formatiun of compound* C„Ii^,,Cl, 
(^H.„C1,. etc. 

In addition to i\w iiK-thodii inentione<l nbovo, tho liig'hpr 
kydrocarbone mny be obtained by buildjn;; tip from the lower once. 
For example, ethane cnn b« obtained from niethiuic by rpplaring 
a hydrogen atom in the latter )iy halugeti, iind then tmutiug the 
hiilogen ronipound thna obtained with Hoditim: 

aCH,l -^»^= C,H,+ 2Niir. 
Propsuo cuii bo prepared iu uccordimco with tbo ioUowing equa- 
tion: 

CH,I + C.nj + Kn, = C,H, + 2>i«I; 
and, in general. ('„1I,il., >s obtained by the KCtion of sodium tii>OD 

[n this mictioii <Mlt.> U foniifd from 2C«Htt, and CtHi from 
SC'DiI. the result being Uint three bjdrocitrbona arc forniod. Tbia is 
alnaijE the case in synth^fiee uC ibis hind. 

Since metlmtie can be prcjmu'd eyiitheticallyi it is ■ovidcntly 
{>oasible to synthesize each hydrocarboD of the fortutiU C„I1,b.^ 



rURMTED HYDHOC^HRONS. 



$9 



58. yo»tt»eJatHre. — Tbo hyiirouitrboiw C„H^„ are . Mn'ayB 
denoted by the termination "aii»." The firet lour m«ml»erB, 
methane, ethnDc, propane, and butane. h»?e special iiarnea; the 
others are denoted hy the Greek or Ijatin numeral correspoudiiif; 
V> the numWr of carbou atoms. Thus *^JI,^ ia called octant; 
C„T1^ ihtiecatlt, C„ll„ Itentrmwiitane, etc. 

ll will often l>u neceeKury to consider groups of atoniE whii^h 
cuQiiot be obtained iu the Jrett iitiite, but which are derived fium 
the hj-dr0(*«rb(pu» C^H^.^ hy removnl of a hydrogen atom, Ttieso 
groupM have the j[i*iutm1 formulii (.'„It,„.,, and are n«ially t-alled 
aik'ifl-groups; Ihey arc denoted individually by changing the 
termination "auo" of tlio corrcapotiding hrdrooarboa into "yh" 
In this way, CH, is c-alled meihyt, C,II( ethyl, C,H, proptfl, C,H, 
but'ih i',tiij;itloilectfl, etc. 

The hydrocuirhoiia C'„n,„,, hare the general name of «ufurnted 
hydrcmrhoiS, brM-ansc they are saturated with hydrogen: that iti, 
are unable to take up any more liydrogen atoms into the molecule. 
Tbey arc also oulled para^uit, hecauou paraffin-wax con^iBts of a 
niixtiire of the higher mcinbere; the word jmritfliii i« derived from 
partitH ttffiiiu, indiotting that tbi« «iib«tance h but slightly acted 
opon by cheitiical reagents. 

83. OccHrreiice in -Vtr/Kri-.— The hydrtiearboiis C„II,„,, occur 
in uatlire in enormous (iiiHi)litie;:«. Cnide j:Vmeric»n petroleum 
conslaU of a mixture of a great number of these compounds, from 
the lowoet to the highest meniJ)ora of the neriea. Three prinoiiwd 
produ'-ta are obtjiiiii'd from this ]>c<trolc>uin by fruetional ilititillu- 
don, aft4>r treatment with aeida and alkalis to free it Jroui sul)- 
rtanre* which are not hydrocarbons ol the formula C,,!!,,,,^. The 
Dost luhitilo portion 18 culled peiroi«nm- ether, Acmifur, nap/it/Hi, or 
Hjfrvin; it diBtils bt-tweeu 40' and ISO'"", and coritaioa lower nicm- 
bcn, chiefly C^U„- t',Mw. «nd C,H„. It is extensively employed 
U a solrcnt for futit, oiln, and resinii, and ia also afiplied to the 
removal of etainB from elothing (" Dry-eleaning prooecs"). 

Tlie portion whieh distilfl at ^^0^-^(K)'' is onlinary ^rfroiftim, 
■od ta used on a large m.-alc for lighting and cooking. 

Tlifl dai)((«r involved in lu use is by no means small. M-fiOrf of ac- 
cidcnts by firv boing ntlributAbl« to tlii« tuurce. TUe fact that fires are 
odeu cauaud by Dieovorliirniiig of fietrnleum iNinpsiK Traceable loltie 
pKftenc« in the petrol«aiu of a part of the more valnilk prodtKls, 



: 



'4e 



ORCMttIC CHEMISTRY. 



vcbo«« vapour prottucea *t) inflamtoable mixture with »ir. If a Iakip 
is QDcil with petroleum fram which the more yoUtlle portions tiHve 
)>o«a rftmoved bv onnfal rmcuoniitioTi, upMiting exiinguinhM It. 
Petroleum of this kind is found In comuerco iiiider the iiftiu« of 
kif^sate or t'ffinfft petr-tltfnm. 

For the purpose of nscortairttng vhether a aanipte of petroleum 
contains) these mon rolatild produt^tx, its jtaah-paint is detcniiin«d 
"hy heating it kIowIjt in » specially coiistrucLed nfiparatua, dcTisad by 
Sir FnKDiOilci: Abei., nnd observing thii lcmperatur« nt which Ibo mii- 
turo of ra[>our and air owr ihc [Milrolviitn can Ju»t be ignited. Ex 
pertence Has shown thnt then.' is no dangL>r witli a flash-point of 40^ C. 
Larxe quantities of petroleum come into the market with a Aash-point 
of S'2°-S4''C-; theso are (h« cheaper kinds, vhtch are lucd by th« 
largiat proportion of thu ixipulatton, and constitute u grt-nt source of 
danger from fir«. It would bo very adrnntagenus it tho law insiiled 
apoti a flaah-poiat of about 40° C, wtiich hits ulrowly beeti adopted in 
itome countriea. 

The nortion of th« crude petfoleum ■which doea uot distil below 
300'. but remains in tho still, ie named vtiseUne. It 'm n scmi- 
eolid subatHuce ttt urJiimrj- tcmpcratureB, wlitt« wlicu {lurv, and is 
QBcd in phannary ia tho prepaiation of ointments. It is fuHhrir 
rnnde Ui^n of /or mrering the aiirfaoe of metHlltc artidea to protct 
th«m from oxidation, fnr wliich purpose it ie bettor than fat, 
because the latter tumi> sour and then attacks the Burface of the 
metnt, u-hereiut vaseline has u ueatrul reaction, and remains un- 
changed in the uir. 

Pftra^n-wax, as olrcftdv moniionbd, ie a raixturo of tho highest 

memb*>r« of the 8prio8 C„II,„^,. Some kinds of rrudo petroleum, 

uotAblv that obtuined from Java, contain oonKiderablc rjuniuities 

ol th««e highest members, which occur to only a email extent in 

'American petroleum. 

Ztqmd paraJHn is » product of high boiling-point, obtained in 
the dry difltillatiou of bro«-n coat 

EiiTUi-wtix, or otol'tTite, is fotind in Onlicin, nnd coneUte chieBr 
, of paraffin. Thifc substnucc h alto obtiiinml in the dry distiUatiuu 
I of tbe brovn coal lound in Saxony. 

U. Petroleum has probably been formed from fals under the 
influoDCO of high luiuptraiure oomblnod nilti gi-eat pressuni. In fact. 
Ekuleu has obLaniod a liquid ver}- fiimilar to Atnorican potroleum. by 
dlsttlUng these substances under lourease'I pressure. Opinion is 
dlTKlfid concenimg the origin ol theee fats. Acajnlinif ti> some, ihcy 



HOMOLOGOUS SERIES, 



4> 



ar« doe to fiih; but it is difficult to undflrstnod how tbo enormoiia 
quantities of iwtrolfum found in Biimeiilacwtuuiildlinvclnwiifornietlla 
tbift wny. Anotlier oiplimnlioii aliribuies its (onnatiou txi TAf}- ftmall 
orgftnisms, ciillird Uiatoma; tlji:»e v/evo present in enormous numbers 
in the «arli4>r gMilngit^al itcnc«J». "i'hi-y priuliicod n «ort of Wftx, whioli 
yields ifotraiuum vihea <li»tillfd utidcr prcsBun:. 

Anollivr hypolbcsts line b^mi $ii^i.'t^(«(! by Moissak. Tfabaitributes 
the (orniatioQ of pntroleuro to the action of water on certain metallic 
carbides vrhich ha.Te been forniQi] by the intense hetit of rolciiaoMt. 
On trcatm«til vrilli water, inoil of tbeaiivarbidvsj'iolil giutcoua bydro- 
caTl)oii«, tt«]tt'i;inl1y inotbnuv or ftvulylotiv. nnd ir Itus biH-u proved thnt 
tb« latt«r ^leld a pctrolcum-bkc liquid when cipotcd (o high pressure 
aud temperature, Siuoe petroleum vnrics gr«atfy in composition, ac- 
cording to tli« placo wbora it baa been oblftined, it is poesible thai ij(>tb 
bypotlie&es are truu {'^'. 13$}. 



HomalofcouB Series 

3S. Ench at the hydrocarbons CaH,„„ tliffcra in composition 
from tho Twt by rt X OH,, n» is At once ii<i*n from the goueral 
forintiln. It hns lw«Ti nlrondy pointed out that tliin difTtreneo 
exer^^is^ft but n slight influence on their chemiral prDjiorties. 

Whenever organic compoiimls show grfitt rt'senibliince in their 
ch<>mical prnpertiea. and have at tho eunic tiniu a dilTorcnce in 
composition of n X CH,, thcvurv Buid to bt- hrjmohfftnts, the name 
homoiogovs $9rtM being given to siioh & group of compotindB. 
Many of theae Beries are kuown, as will ha se»n later. 

It is easy to nndorstatiil how much this eimptilles the atuily of 

organic ch«?mistry. Iiisteu-il of having to consiiior the chemical 

properties uf cuclt compouud individually, it ia stifllciunt to do ho 

for one rnvmbiT of a homologous serica, as this givce the principal 

characteristics of all the other mcmbe!"*. In addition to the 

mnin properties (common to oadt member of u bomotogouii iierit-s, 

ihoro HTQ pecul iaritiei) special to each iudividusl member. Except 

ill A few intitAncea, tiiis book will not dwil with tlic*c, because 

iliey only nuod to be coiuidDrui iu a laorc extensive survey of the 

subject. 

36. Tho phyticat properties, fmch aa the melting-pnints and 

boilin^-]>oiiit8, specifiR gravities, and mol it bi lilies, of the memlirrsof 

11 hnaiologona series, generally changf uniformly uk the immhor of 

varbon atoms incrciweA. In general it may be euiJ that the melt- 




4* 



orcask: chemistry. 



fa)g*pcnDM and boiling-pomU rimt from the lower to the higher 
members of a homologoas series. 

A table of Bome of the phvHtcai conatontft of a nnmber of 
Donoal members (iO> of the puraffin scries in given below-. 

It is Been from thia table that iho first four m<>mben are ga««6' 
at the ordiiiarr t<'m|>9rainre, tho«e from C^ to C^ liquids, anil th« 
higher mumbvre solids. Although raetlian« m odonrlee^, the litiuld 
members have a characteristic petroleum -like smell; the »o1id 
members, on the other hand, are perfectly free from smelL The}' 
arc all ulmotit iue«lDbl« in vat«r. 



I 



Fir* inula. 


Hua^ 


IMttM- 
pDac 


potai. 


SpkUo Onritr- 


CH. 


M«itiKn« 


-IW 


-!«• 


0-4l5(al — m*) 




C.H. 


>:ttia»e 


- ITS-l* 


- s*.r 


0.44S (mi 0') 




c.n. 


Prapuie 




- ar 


O-OM (U «*} 




C.H.. 


Bbuiw 




r 


0S«7 iai U'] 




i-,n„ 


P«nUa« 




«r 




c.ll.. 


UrZADv 




w 


0-«W(«tM*) 




C,[|,. 


[lepUiD* 




•r 


0-W8 .. ., 




c.ll.. 


Ueune 




iw 


O-TUt „ ,. 




C-.H.. 


Nonati* 


- a' 


ISO- 


0-718 .. .. 




C't.U.. 


I>*caTi« 


- 31* 


ITT 


0-780 .. „ 




C,,l].. 


VodnrtJi* 


- 28" 


Ito* 


0-7?4 at lite meltlng.polat 


C.IU. 


IkudfVBIMI 


- 13* 


814" 


0-7W 




CHm 


ttinAtvt,a* 


4° 


2S3- 


0-""5 




C„H.. 


HexKdMKBa 


18' 


28r 


0-775 




f.,11., 


EleoMae 


87° 


ai»'» 


0-7T8 




*-\,»u 


HMialMHu>n« 


«)° 


sir 


0-778 , 




t«H., 


'I'rieuwiv 


«■ 


*M* 


0.77» 




c„n.. 


nviilri*coiit«n« 


68* 


802* 


0.78! 




C,.IK, 


FrnuirIacoDUfi« 


tv 


881* 


0.788 




Ci.lliti 


li«iftMintana 


lor 










■ At IS mm. ftri 


•.■in. uiil III. 


■tinn fur 111 


H> follumluf. 





It should be further remarke<l 
meltin^-pniiita and boiling-points 
ben of the series become Bmuller 
carbon atoms. Thi^ phi-uoniunon 
serieo. 



that the diSerenoeg between the 

reKpoctirelj of sijccesaivu mem- 

with inereose in the number of 

is usually found in hooiologoug 



iBomeriam and Straotnre. 

87. There in only one snbstanee known with the fominia CH^; 
this l« mpthane. Simllurlr, there is only one rompound having th* 
formuln P,II,. ami one with the formnla C,H^ There are, how- 



l!iOM£RISM AUD STRUCTURE. 



Ai 



ev«r, two I'umpoiinils known vith the formula C,II,,, three with 
tho fnmiuin C,H„, five with the formula C,7I,^, ete. The phe- 
tiom<-)ioii of two or moro comiionnds boiiig repreaeLtod by ouw 
fomiulii u c-ulli-cl ifiorriTiVm (2). iiiitl coit)iK>iuiilii buviiig tht- same 
fommht arv c&llud tjiomern. This iit cxpluiiiL'il by a ronsidcnitioii 
uf the way iti whk'li the utuiuK Ar« {croiiix^d in the iiioloctile. 

One of two )iy[)othoiicii niuy he udflptod. In the tiret place, the 
urmngctnent of the atoinH may bo regarded aa continually chuiig- 
inp, a molpnule heing rpprcfiented iut like a plauetHry ayMtpzii, the 
conRgunilion of which rhungi-K from moniL-nt to niuuiRiit. Thin 
hypothodifi, however, cannot t'xpliiiii the jOiviiomcnon of ieomDriHtn; 
indeed, it is not apparent how, for example, the fuiir curhoii atotiu 
and ten hydrogen atoms in butane eoiild form two different m\>- 
8lanc«d if th« nmingement wore Indetenninate, for there are 
trillions of moIeculcR prcwnt in hr_ little as one ciihic- millimetre, 
and nil Uie jwgiiihle coiifign rations of these foiirt<>Bn ntoniii niiiiit 
ther«fore be nuppo»ct1 to occur overy moment. 

Isomensm can at once be underetodd by asenming that there is 
a defiuile and uncbaugiug urnmgeineat of the atoms iu the 
molecule, becauoe the difference in the prupertios of isomeric 
componiide may be then explained by a differenoe in tho arrange* 
meut ol equal number)* of the same at«nu>. 

A deflnit« and oncliaiigiiig arraugouieQt of tho atoins in a molA- 
eolfl doeanol involve (heir being iniiDovabte in relation to one another. 
Tbey may L>e suppoeed, fur exaiu[>le, to revolve round a pusitioa of 
•tiulllbrlum wilhout any alteration iu their onler of tuccesslon. 



88. Since tin* phenomnnmi of iaomeripm leads to the assunip- 
tioD of a deduite arr^ugcmotit of the atoms in the molecule, it 13 
necesdary to answer the (|ue»-tton as to what the arrangement of 
the atoms in the inolemilcs of different coiiipontii]); in. The start* 
ing-ixiiut for Ibis is the tetravalency of tlie carbon atom. In the 
omso of methane the arrangement of the atoms may be repreavnted 

by the formnla ('^<it- ii which the four linkinga of the carbon 

iit«m ttX, aa it were, like four points of ottraction, each one hold- 
ing a moaovalent hydrogen atom faiit. Thig is the only possibility. 



44 



ORQ^MQ CHEMISTRY. 



bcciiuae tlio hydrc>gon atoms csnnot be bound to one another, eiaoe 
the only point of attraction, or fiiugle linking, of each of them ia 
alreudj in uuiim with oiiu of l\\v linking of the cnrbon atom. 

Wo shall now try lo lucertain l.ltc anungoinent of the atoms in 
ethano. C^H,. This 8iibstancc can be nbtainod hy the action of 
aofiiiim uiHiji methyl iodide, C1I,I (31). \Vu have here a teira- 
vbIviiI carbon atom, three monovalent hydTOgon Atoms, and one 
monovalent iodine atom. It must thereforo bo rcpri}Bent(>d thus: 

Sodiam Msotfl with methyl iodide in nuch n way that the iodioo 
fttuHii! are abstracted from two nioleculee, with formation of 
ethane. The removal of the iodino atom has the effect of setting 
free the carbon lirikiDg previously attached to this atom, with the 



production of two groups H-^C — . 



SiU'Co the formula of ethauti 



ia C,H,, it is evident that the only possible arrangement of ita 
atoms is tho one in which the two froe linkinga of the methyl- 
groups are tuiited to one another: 

H-5(— C^H 

The aTTangement of the atoms in propane can be determined 
in nil exactly nnalogons manner. It hiis boon mentioned (31) that 
propane I* formed by the action nf ^nilinin on a mixtnrc of methyl 
and ethyl halidc.<<. Sinre ethane nan be prepared in the way iu«D- 
tioQcd above, tho formala of an othyl holido can only be 



vhere X rnprewnta a halogen atom. ■ 

Tf ll'o halogen ii talten away from this and from methvl iodide 



fSOMF.RISM AND STRUCTURE. 



45 



■t the mmv time, the rasidaea units together, alioving that 
propane hius thu followirg rtrncturo: 

II 

Hv J /H 

H/ _^ XU 

"or shortly H,C-CH,.CH,. 

An arrang^meiiC at Bvmbola like this, whtt^h expreRses the con* 
B^iration of the atoms iu n maIt;ruU<, thus indicating the form or 
Btnidture, U called a struclurn! or constitittimal formula, 

39. The foUowini; example mukos it clear how caww ol isomor- 
ism CUD bo uxphiiDed hy differences in Blnictiiri>. Among the flT« 
k nowii hcxaues there is one nrhirh Itoils at 69" nnd has a epecific 
gravity of 0-6583 at aO-O", and another which boils at ^S" and hiu 
a specific gravity of 00701 ut 17-5". The firet ia oht^ned by tho 
action of sodinm on normal jtropyl iatlide, CU,-CI[,. CU,!. It 
follows from what haii been gaid ahore that thie hoxADO mu«t haw 
Iho Btnjoture ■.'. l/,i/ / 

cn,.cH,.cn,— cii,.cH,.cUr ^- i ). -\-\^'^ 

It is Cflltod tiipropifl, on tho asxiimption that it has been lonnrd 
by the union of two propyl-groupn. 

In addition to this normal propyl iodide, an isomer is known 

liaving the name ixopropyl imtiile. Itoth eom|inuni)a can bo 

eti«)ly nonverted into pruiMine, CI(, ■ ClI,- CIl,. Awnming that the 

ifuimmsiii is due to n different arrangement of the atuma in the 

molpculv. it follows that the iitomeriiim nf the tvo compounds 

(',ir,I can only be v^cjtlaincd by a differpnre in the position occu- 

pitd by thu iodine nioni in the moleeule, beL-atiHo the arnitigement 

of the atoms in propane is known, and the propyl iodides only 

differ from propane in having one of the hydrogen atoms in the 

litter replaced by iodine. Isopmpyl iodide niudt therefore bars 

ihe structure 



t 



U 
C11,.C.C1I,, 

I 



the conetitution of normal propyl iodide is CH,-CH,-CH,I. 



4fi 



ORC^mC CHEMISTRY. 



The hftxano boiling ttt 58° is produced by the nction of tiodiuni 
oti i^opn<]vyl iodide. From tlii^ uictliod of fonuutiou it is evtduni 
diac tbid hcxiine lias tlio Ktruoturc 



or 



CH,-cn-cij, 

CH,.CH.CH, 

For this mason it iti uilled iH-improptfl. 



^«;>CH.CH<^g;. 



CM, 



cH,-C-C--t*(, 



CarboB Chains. 



CN, 



40. It is evident from the f<jregciiig that the faota nec«eutat« 
the asfliimption of a bond bt'tween carbon stonui in the mole- 
onles of orgttuic coui|M>iiudH. 77jm bond is a v»ry ttrong one, for, 
an we liHTt* ttlreadj' 8«eD (31), the itaturat«(] hydro<^rbonii resist 
the action of powerfnl chemifjil nvj^iiU, Tliv [irupcny piMweased 
by carbon atoms of combiuitig tugetber to form u acri«8 of msnr 
atoms, a rarhtm chain, lilce that in th» hexautfti abovr dcacribiH], 
funiiahcs a marked dietinction bctv-ei^n thetn and the atoms of all 
the other okments, which either have uot this power, or only in a 
Tory inferior degree. The fact that the nnmber of earbon (-om- 
pounils is so enormous in due tu tliia propertv, in cunjiuictiuu with 
tho tctravaliL-ncy of thu eurbon atom. 

A caTboii ehaiQ Ukt^ thut iii normal hi^xane (dipropyl) is said 
to bo normal. On the other hand, thore ie tho branched chain, iin 
•xamplc of whinh ia furnished by di-ifiopropyl. >iiob fsrbnn atom 
in the normal ehain i« linked dirtfctly to not more than two others; 
in branched rhnini; there are carbon atoms whieh are dirently 
linked to throe or four others. A normal-chain compound in 
usnallr denoted by putting n before itH name; branched-f^tiain 
compounds arc often diHiug-uiehed by the prefix iito. 

A few otiior definitioni; niny tind a jdacc liere. A oirbon atom 
vhioh is only linked to one other onrbon atom is oallod primary. 
Tf it is linked to two carbon atoms it is nametl sfcondary; if to 
three, tertiary: if to four, i^ualernartf. A rwrbon atom situated 
* at tlie end of a chain is called lertninal. 1'lie carbon atoms of a 
chain are dietiugtiished by numberu. the tcrminul one being 
denoted by I, tlie ono next it by S, etc. ; for example, 

CH.aH,.CU,.CU,. 
I 8 a 4 



NUMBER Ol- POSSIBLE ISOMERS. 



47 



Sometimes %\w tcrminiil atom is donoted by to, the one linlted to 
it bj II, and the jtuet-evding one by fi, «tc. 

L>w of Uie Evas Smnban of Atonu- — The number of hytlroKen AU>ma 
In t)i<! saturateO hydruoHrbotis uiiisl bi- an even one, !<iaoe their formula 
in Cail*n>i. All uth«r OFKanio uompouiids uiAy Iw re)!;<inlpd ssbeiDg. 
denv«<l by (]]{! cxchHng« of iheRehj-drogeii ncnriiK W ottiur pltfiiieiiu' 
orgroujifl of aioms. or by llic ivmoval of an ov«n number of tiy(lro);eii f 
maniit, or by bolb cAUses ftimultauvouBly. It follovs from this thAtj 
Ibc ftUiD uf the Atopis nilA unevon valency (hjdrostiu, the hxlogeiu, 
iiilrugvri, ]kliCKi|ihorus, cic.) must always be nn cvf^n [inmber. The 
moleculs of aeubstftDcc vrtiuw empirical compusilioii is dUiXUi must 
be at lea«t twicu an great »s this, bec»ufte 311 -i- IN » uueriiii. 



Vumber of Fouible Isomers. 

41. The tctravatency of the citrlion ntoni, couplvd with tbe 
principle of the format ion of cbsitis of RtomB, not only euabtm us 
to Ji''<'<tuiit iiii the Jsomors which art> known to esiBt, but slso piitg 
us in tlie position tif bi<ing nble to preilift tlio existence of rom- 
p«Hinde. For a compound C',Hi„ , for c-xamplt*. either the structure 

Cn,-ClI,.rH,.CH, or ^:]}»>Cn-rn, may V atwnmed. »nd in 

this case there aro no furthtir possihitities. Pentune may havo tbe 
following structural formulii;: 

(1) C'H,.CH,.CH,.CH,.CH,: (3) OH..CH,.Cn<g^; 
(3) ^5»>C<?5. 



CH. 



CH," 



For heixauo the following firo arfi posubic: 

(3) CH,.CH,.CH.cn,.cn,: (4) CH,.CH.CH.CH,: 
CH, CH.OH. 

/CH, 

If the principloa given above be oBGumed, it will be impoiuiibto to 
find i^rni'tiiral f()nnul»' other than tlioee «ientione<l. 

Should it he jiottiiible tu actually uhlain the same uaniber of 
isotntTs u8 can bv thus jirvdictod, and uo more, and shonld the 



TRGANK CHEMISTRY. 

pnxlacts of syntKoeie or decom^iositioD of the existing isomers 
ii^eedsitAte tlio Kssumption of the enme ainicttinil forinulie as ttioeo 
n'4]inriMl by tho tbi>ory, thcM? fiu^u ouiigiituto a very iniportaut 
conflrinatiriii of the correctness of rhe priitcipW u^Ktn which th» 
theory is based. This has in f«ct hven jiritveil to hol<l good Ui 
iiuinerons iiistaiicce. ait<] therefore, on the ciher hand. nfTorda an 
iniportaiil means for determining the structure of a compiHiiid. 
bacauae if nil the RtruL-turu) furniiiliB which are posaihlt! for tlie 
oompoiniil at'oonling to tho ihoorj- are t*oii«ideivcl, oin' of them 
will bi' found to be that of the (tubstiinw. 

In very many tases llio number of isomers ut'tuidlr known 
in niUL'li similier than that whicli is posaiWc. Thi« it due to 
the f«i-t that ihv nuinl^er of iw^ible iBonit;r« iiicrviiH-s very 
qnirkly with incroiisc of the number of rarboii ntonie! in tho com- 
poiniil. t-'AYi.RV hiis calculatfJ that lh«re arc nim' possible 
isoniere for f,!!,,. ciglitBen for f,!!,,. tliirty-fivo for t',H^, 
seventy-five fur t'l^n,,, oiiu hundrtd and fifty-uinL- for C„Hj,, three 
hjindred and fifty-foiir for C,,!!^, eight hundred and two for 
C'„lt„, etc. OheniiEls lutvo not Irieil to prvptiro, for example, 
cvei7 on« of the eight hnndred and two possible iwniera of the 
formula t'i,H^. bocmiee their attention hun been oecupietJ by more 
important proMeniB. There ejin. however, be no doubt as to tho 
[xi^ibility of obtaining all these rnmpo\ind», because, as mentioned 
above, the metliodi) for building them up are ktinivn, and there 
would therefore be no theoretical diHiniltics in the way of tbeee 
experimcDtSj though there might be hiudrauccB of an experimental 
nature. 



FhTueal FropertiftB of Iiomerie Compoondt. 

42. Th[^ norriiitl compound has (be highest boiling-point among 
the diffcreut iaomere, and this rule holds gooil in generul for 
liomologoua .icriei; other than that of tho methane hydrocarboiid. 

K:/ample. Xdrninl hexane boils at tid°, and the buihng-pointa 
of the different iconic r.r are: 

Mcthyldiethvlmcthane : {C.II^.CU ■ CH, 11. P, (J4». 

Kthyliwbntyl: i;,U,-CU,-C-Il(CUJ, „ n\ 

Pi-ieopropyl; {CU,|,CH-CII<i:ll,), „ 58°. 

Trimelhylethybnetliaiio: (OH^l, C-C,H, „ 48°. 



I 



ALCOHOLS. C„n^.,0. 

Kethods of Fornuttion and Conatitntion. 

43. The aiomUrs of tliia homologous soriM can bo obtiinwl 
\iv th* action of silvpr hytiroxido on thp alkjl Jjalldea: 

C:.U.„.,1 + AgOH = "CJCIIo*! Agl. 

It is iiBuul tu bring un alkrl iodide in contuot witli moiitt oiido 
of etlvor, of whicli tbv (lurtiou dissolved iu Lliv wtitcr rearU like 
aiker hydroridc {" Inorgnnio Chemistry," 246). The prepurJitiou 
of the nlcotiol from llio i>(>dide c^n also bo cfTpctoil by heating it 
with oxcesg of water ftt 100'^: f j,,/^!/ 

When stxliuKi reai'ta urith an ali'uho] C„il,f,„0, one grHmine- 
stom of frpc liydrofteii ifl libcrulud from racli grnnimfl-niolpnile of 
tlie rtlcohul, ntul H ortmpoiiiid nillcd soilium nkohohlt witli the 
formula CBH,„.,NnO is prndnodd, whifh (luoomitoiws in presence of 
es<'<>sii of wfttiT into XnOll mid iin nloohol. The gudiiiin hat: thus 
repUif»«l one atom of bydmgeii, auii neith<^r il iior stiy other 
inrtui cttii reiilacp more than one hydrogen atom; if exoesii of 
sodium is adde<l, it ivmuinii iiiiucted upon. It follotts that iliere 
is only one bydrogon atom in tho *lcohoI which is rcplac«iible by 
Bodinm. 

When lUi alcohol is tn>ated n-itli trichloride or peDtaohlorido 
of pho4pboniit. au alkyl rliloride i» forrned: 

3C.H.,..o + PCI, = 3cX..oi'+ tr.Po.. 

Vie ehall iuid«aroiir to deduce the coustitutioa of the alcoholt 
from llicB* faets. Silver hydruxidp ran only hn%'p the structure 
^g — — H, its divalent osygeuatoni being linked to itsmonoTAlent 
silver and hydrogen atoms. AVheii eiWer hydroxide is brought 
into contuot with an alkyl iodide, thf reaction must be Mippoeed 
to take phict; in eiiuK a wiiy tlmt uii tlir our bund thi« iodine 
atoin IB Mt fn« from the alkyl-groitp, and ou tlic other hand, the 
eilTcr atom from the hTdri>vyl-Kniup. The nlkyl-group and the 
bjdroxyl-grouparo ihuK afforded llii* opportunitj- of nnitiiig with 
oue mnother by means of the linking vliich has been set fnw io 
jh of them : 



so 



ORGANIC CHEMISTRY. 



This methoil nt formation |)ri>ve8 that tlio Alcohols cantafn a 
hydroxyl-groiip ; their preparation from alkyl io4liilo« umi waier 
leads also to the same eonrlusion, which ia further siip|>urt^ by 
the two properties uf alooliole mentioui:(i above. It iii evident that 
if their etnictnre is expressed hy C„IIp„,-OH, all the hydro^^n 
Atomi) pppaeiit, ext-ept one, are linked dirnntly to earboii, wliilo one 
hydrogen iitom oei-iipiM a upecnal position in thti molwiile, being 
Kttat^hed tt> the oxygen utom, wliicli in itK turn ih united through 
itH Berond liiikin); tou curhoii iitum. It i« only natural to i<iipp08e 
timt the epeeial jKieition oeeupiod by thi» hvdrogon atom ie iiMom- 
panieil by n i^pcfiinl pi-operty, that of being the only one of all the 
hydrogen Htflms which i« replnocable by ttlkali-metals. Moreover, 
sodium Ht'tfl free hydrojreu from another eomiJcnud which witliont 
doubt cont&ins a hydroxyUgronp: l\\\*. i-uni]ioiiud is wHter, for 
which no other conatitntion is possible than II — — II. 

The fiK-t that the alcohols are ccmvertwl into alkyl chloridtK 
by the action of the chloridce of pbonpliorus is porfoftly in accord 
with their containing a hydroiyl -group. It is seen at ouce from 
the empiriciil formula; C„nj„,jO and C„U„.|X, that the linlogeti 
bu replaced Oil. It ni«y he assumed that in this nMietion the 
hydroxyl of the alcohol La« changed places with tlie chlorine of 
the phosphorus «;oiii pound: 






3(C„H 



A ronsidnration of the possible eoustitutional fomiulne for siib- 
stanree having the general molecular fonnubi C^ll^.^O reveals the 
ftict that on at'coiint of the vray in wliich the oxy^n mom is 
linked, only twu foriuulie are possible; tlius, the i^'ioipounil C,H(0 
could be either 

L 0H,.CH,.OH, or 11. CH..O.CH.. 

Since all the hydrogen atoms in the eceond formnln have the 
same value, jteannot bo the on© representing an alcohol, «*il would 
not noeouiit for a very itnpormul property of these compoinidg, 
the ucijon uf the nlkali-metaU upon them. The action of stiver 
hydroxide on iiu alkyl iodide, or that of PCI, on an alcohol, would 
accord e(|ually ill with this formula, whereas formula I explsina 
three nttctioiis fully ; it must therefore be adopted. 



^ICOHOIS. C„Hi„+*0. 



S> 



I 



Tlte coDStitutionnl formnlic of the alcohols tmve thus been 
dedupfitl frcnii their pmiiertieu. Invcreoly, f/te comiifufionalformti- 
ta> arrounl /or all the chemital properties of the compounds, being 
simply a abort way uf expreising th«m. It is easy to soo how 
valuable thcne formulii! ure; bec»iiiii>, if it is prt^giblo to derivu a 
structural formula by studying eorae nf the properties of a com- 
pound, it vill be possible from this to deduce its other properties. 
The exist«nce of propt-Kies indicuted in this way has in atimcroni 
inttanoes been estitblisbed by oxponmout. 

Homenolature and IiontcriiBi. 

44. The alcohols of this eiTiuH lire naiiitx] iifterthe aIkyI>groupe 
containtHl in thum; for ('.xam]>U>. methi/L eChtjl, propyl, etc?,, nlcoliol. 

Isomorisin may arise in three waya: by bmnching of the carbon 
chains, through the position of the hydroxyl -group, or through 
both thc«e causes simultaneously. 

This 19 Been from the following tabic of tlie iHomcrio alcohols 
C, to C,: 



JTuMl 



nvpft alc«hoU OtHfO 
1. N<iniial 
S. Isn 

1, Nomitl prinur7 
S. „ wMondujp 
S. Uti 

4. TriraMbxIcarbtnoI 

1. Nomutl pTlmur 

2. iBotimvkkibiDol 

5, BMviiiiJftr; butyli'ArbinoI 
4. MpiLjli>r(ii<ylcai'biiin1 

S MoiliylisormfiTlorbinol 

•. Di'tthylcariiiiiiil 

7, Iltmotli;!"!!! 1 kvrbinul 

•. Tenlar; butjIcKrbinol 



Fomulk. 



cn,-cii,-ai,on 

CIl.-CllUlI CH, 

CH..CH,.CH,-CH,OH 
CH.CH.rHOH-L-U, 
(CH.).Cti.CU.OH 

CH. ■(«!,). ■CU,OH 
(CH.l.CH-Cn.-CU.OH 

.<CH.i,CH.rH0H-t1i. 

,c,ii,-iiroii.i,H, 



aoiiiDK- 



er 

117* 

100- 

103* 

88- 

188* 
181* 
138' 
119' 
113-8' 

ur 
loa* 






0-SOi 
0-7B» 

0-810 

0.80S 
0-7M 

0-815 
0-810 



The names containing carbinol ha\e rcferenoe to the fttct that 
•1) ulcohohi may be looked upon us methyl alcohol (citrlinol), in 
vhirh one or more of the hydrogon atoms, with the exception 
of tho one in the hydroxyl -group, arc replaced by alkTl-groH[W. 
Ill itus way, iaobutyl alcohol is culled ifitpropyicarhinol. secondary 



53 



ORGAHIC CHEMISTRY. 



bat^fl alcohol meihylethylcarbinoi, and normul butyl nlrohol n>j»ft^ 
ftylearlinot, «to. 

As is evident from the above examples, a primary alcohol u 
one in which the hydroxyl-group Id linked tu u iirimaiy carbon 
atom (40); vhile in a ttrondary ur » leriiary alcohol the hydroxy! 
18 iiukod to u Becoudary or u tertiary carbon atom reepectirely. 
Similarly, compounds which may b« regarded oe haviug been pro- 
dncod by roplactfrnomt of hydrogcin linked to n priniarj', spoondary, 
or tortinrj' atom are f«lUid primary, set'oudarj'. ur ttrtiarj' com- 
ponnds. Thns primary alcohola ttro represented br the genera] 

formula C„H^.,—CH,OH, aecoudary by C„U^.,— C^C 1I,„.,, 

and t«rtiiUT by 



General Properties of the Alcohols. 

46. Some of the physical properties of the aleohnls are given 
in the following table, which includes only normal primao' com- 
pou nds : 



Mmub. 



HMbvt klcolio] 
ElUyf „ 
Propyl .. 
Botyl 
Amyl 
H«yl 

SJ??' :. 

Nanyl 



FbnauU. 



cn.oH 

CH.OH 
C.H.OH 
C,H,OH 

C.IIuOU 
C.H„OH 

cn,.0H 
c,H„on 



SpwUIC Urarltr 


liaUliic-polni. 


0-812 


M* 


owe-' 


W 


0-817 


87" 


0-83S 


nr 


o-8sg 


1ST- 


0-8SS 


IS?" 


o-BSe 


na* 


0-S8H 


191' 


0.843 


sia* 



BoUtog.poiDUk 



IS* 

SO* 
SO* 

ir 



It is seen that there is an increaw in the boiling-poiut of about 
20" for Dverj- additional C"H, in Iho fonnnlw. A eirailar regnlarity 
is found in other homologous serie:^. This t»h]<>. togetlivr with 
that on page A1, shows that the normal couipoundi havu tlie 
highest boiling-points: and this also holds good for the hydrocar> 
bone (42). 

The lowor alixtboU (C, — 0,) are mobile liqnids, tho middle 



METHYL AND ETHYL ALCOHOLS. 



53 



jone« (C, — C„> ar« of a nioro uitjr nature, whilo tlia higher mom* 
hen urc Kulid at thu onliiuin' tt-in|KTnitiirL-: al) »ru calaiiTlctis, at 
l«?ii«t ill thill Itiycre. In thick luyora they arc slightly ycUovr, the 
colour bi't'oniing more tniirked with increase in thi' niimbor of 
caTlwiii atoms. The tirst mfmbera (C, — C,) ure mjHfiiblo in nil 
prujiortionii with vater. but the solubility of t\u: higher nieiiibctrs 
tliminiiihes (jiiicWly »h tlm numher of cjirhon iitninn in(-reiu>ei(. 

The lower tneniitcni hu\R ii »pirituau!i Hmell, und the middle 
OHM a dtsagroc:uhle one, vhtlc thu eulid tuvoihcrB are odourless. 
Their dpeciSt- gravity is lesa than 1. 

Methyl Alcohol, CH/>H. 

46. ThU Kiibjstance is obtaiued on the large Hcale by the tliy 
diKtillation of wood in irou rt-torts ut u& luw u tcmperatttro as 
possible; or buttt^, by Iroutitieiit of wood with hot produfrr-gtw, 
vhioh in a mixture of carboTi iiiouoxide and uitrogcn, ohtaiaed. 
by paesiog air orpr coke at a white heat. To thc«c methods of 
prfrpanition tlic mihstaiipe owes ita nanic wood'Spirii. Tlio 
productii of the distillation arc giiM-'s, uii iif]iieou» liquid, and tar. 
Th« aqiieoiifi Rolution (-ontains methyl alcohol, &long with a 
Qum)>er of other auhHtanceit, of whi«h the chief are »«*tic arid and 
ncfilone. 'Hie acetic acid id ma<lu to combiDe with lime, and the 
methyl alcohol purified by fractiontU dirtillation, and other methods. 
It is tilled in comnierco in the prepamtion of aniliuc dyes und 
formaldehyde, for the tlmtiluration of Rptrit so m to render it iinSt 
fordriuVing purimees (48), etc. 

Methyl alcohol burns with a pnle-hhie ftame, and is miscible 
with water in all proportione, the mixing Wug accompanied by 
coutnK'tion aud the development of hcut. IXe nieltiug-poiiit ii< 
— ya.W; its other jihygical propertiee will be found in the table 
on page Ti'i. 

Ethyl Alcohol, C.HjOH. 

47. Thia 18 ordinary ulcoho], sad is prepared artificiallj iu 
cuormous qnantiticB. It." prc|>(irntjon dependa upon a property 
possessed by ^hieose, a sugar with tbe fnrmiihi ('(Hu'^' "' decom- 
posing into carbon dioxide and ulcohol in presence of jftast-celiM : 



54 



ORGANIC CHEMISTRY. 



About <J5<( of the glucose deoamp<»Bes ^■t.-ording to tliie fiiuation; 
a number of liigber hIl-dIioIh of tliia fii<ri(>£, cbiefly autyl ateohoUt 
C^„OU, are formed m by-producLa, togetlier with glyccTol, may 
cinie acid, cto. 

In Ihu Luehtiicttl miiiiufitcliin; of ulcobol, (his KUgsr itttc)f h not 
OBod 08 » bmiU, owiug lo iU boiiig too co«tly. Sonio xubetaiicc 
rich in stjuwh, (C^H^OJ,, «ich an potatow, grain, etc, ie u*ed 
instead). Ry thp action of mtymtf, the Ktarah is almost oomplftcly 
oniiTerteii into wn^/ow, f'^jlI^O,,, one molocnle of t)iiii oomponnd 
bring then converted into two molecalns of glucose by th« HCtiOQ 
of one molecule of water: 

c ii„o,. + n,o = 8cn„o.. 

EnxynuM are clieiuleAl oompoands (unorganized femnonis) wbioh 
have tho properly, wlion oorLain itubstuucett am brought into contact 
with small f]uantltiM of ilioiii. uf causing Itiesosulii^raiicu toileenui- 
pofv, in niost cases with addition of ihe Bletoents of water. Tlicir 
contttitution and ibe way in which thpy act are both unknown ^33S). 

Thci particular i^ntrmo wliicii \ft uhpiI in the teithnidal ntanufiio- 
tnro of miitloKe from Ktarch ir railed ditigianf; It is present in 
itproitting barley. The n-actiun to wbii'h it 
gi%-e« rise li called sncrharificaiion. When 
potatoea ara nsod, thoy uro firet rna^c into 
n thin, homogeneoue pulp by treatment wttli 
«t.cnm und«r proBeitre at 140° to 150% apront- 
ing barley beitig theu added nft«r cooling. 
At a temperature of fiO" to fVi'^, the decom- 
position into maltoee is completed in twenty 
minatos. 

.:Vfter the maltose solution has been pre- 
pared, yeiut iti added, and ilio (<.'rmenlation 
onrrii^ on at a t^mpeniture bfleto 33°. In 

order to sepitrat'i 
the recinltiiig uJ- 
fiohol from tho 
other fmb«t«ucos 
which aro prM- 
ent, the product 
Fio. 28.-FiiACTi«N^TiN«cyi.uMs. is Kuhmittwi to 

distillation; hy using ik/TaclioHaiiK^'Vot«mH (Fig. 2;l), alcohol of 



WB^M ' 





ETHYL ALCOHOL. 



5S 



90<t streogtli can hn obtained, althotigh the oncontratioQ of tlie 
alcohol in the fermttuted llcjuid drte^ not <3xceed 18j(. 

The thia liquid rei«idue remaining in the Ktill ih called gpetii^ 
mvih, und im uanI Soi hal'iag uittlc; it contains, amon^t other 
things, alnioiit all tbo ulbuDiinvuB «ul)Btiuic«8 presont in the 
material from which the npirit has been mnnnfflcttircd. 

The cruel* )i|>irit (low wines) so jirejianid iii a^iii iiarefuUy 
fractioBated, when alcohol o( iHifi hy vohinio (»pin'lf) in ohtaiued. 
The frartions of higher hoiling'point consist of an oily lir^uid with 
an iinplea»ant smell, which iB chilled fusit oii, and contains chiefly 
amy) alcohoU and other homologueii. Tho residue is called fijent 

Abntwlic beveraytt have long been known. Tliey are closclfled 
into two uiain liivisiona, those that, liftve Won alistilldd nnd tlioao that 
have not. To iho first clans Iw^iong hmndy (tO-SO* alcohol), gin 
(alcohol diitilled wi(U jitniiivr berrin), (-vyriac<obtain«d b>' dialilling 
wine, Hbov« see alcohol), tjlc. Tbo secoud vlau includes be^ (8-4^ 
akobol), tffint (S-S-IIMC alcohol), madeira (up to 21$ alcohol), etc. 

48. The alcohol of commerce (jyiiri/j! o/wme) always contains 
vater. In order to obtain anhydrous or ahsolule alcohol from thia, 
lunipB of qulcli.lime are added to spirit containing a high per- 
oenCage of alcohol, imtil tho qnicklime Khows ttuolf above the eni 
iwx of tlie liquid. The latter is then allowed to stand for some' 
d&ys, or boiled for sereral hours nnder a reflnx-con denser (18). 
after which it is distilled. The preparation is much facilitated, 
and the loss, which is rather large by this method, is reduced 
to a minimum, by introducing a apirit of high percentage along 
irith u little quicklime into a vat, which i^ then oloeod by a «ercw 
lop, and heated some hours at lUD'^ in nwater-bntb; the spirit 
U then diiftilled. Id order to prepare abaohite alcohol from dilute 
alcohol, the latter must first lie concentrated by distilling it from 
a waler-balh. This can also he effected by the addition of solid 
jHitawium carbonate, which oaueea the liquid to eejiarato into two 
Inverv, the aqueous cue bi>Iuw and the alcoholic ou<j above; alcohol 
of 01 •&< by weight in thun obtained. 

AbsMlule alcohol iii a aiubilc, colourless liquid, with a charac- 
ipristic dmcll. ll solidifies at — 112-3\ aiul burns wilh a jiale- 
Iduo. iion-luraijioua fianiu. It is very hygroscopic, being niiBcible 
iritb water in all proportions with contrsctiott and rise in tetn- 
peratnrc. The maximum contracltou n obtained by mixing H 



OKGJiiK CHeHtSTXY, 



I 



of alcobol irith 46 Tolumoi of irsur. the Tolume of tlie 
imhmg mtxtttre at 20" being i>6-3 instead of 100. 

A Met for abeolnte alcohol u its beluTioDr iritb anhrdroua 
Mpptmlphatf, whirh rematiu porfectlv colonrlesA when in contact 
wish ii, wbetou if the eltgbtest trace of water in present, the ixipppr 
Blpbate derekips s light-bine colonr after several honrs. The 
tp e t Hc gnritv, a pbTvic-al oooBtant which is often Dsetl toaocertain 
the parity of itqajtl compounds, muy alau he trmfiloycd for the uana 
parpoM. 

On acconnt of th« (Ttcai importanco vbicb a knowledge of tho 
■moant of alcohol in mixtnrve of wstw and aloohol has for indus- 
trial ani] Gtcol piirpoRe«i. it a nocesmry to bare a moinod for 
qnicklv and easilr determining thi^ Different cheniiets, amonp 
tbcm VON BAi'MiiAt'RK, hare shown inat the determination of the 
ipccific grarity and the temperature of sach a mixtnre, alTnrda tbv 
easiMt method of effecting this. For iiiis purpose a table has been 
prepared with gr«at accuracr, ubowin^ the epecific gnritiea of mix- 
tures of aloobot and water from v^ to IWf, at tcmperatDres between 
0" and 30^ When the sfwcifie gravity and temperatare of a given 
mixture liave been deccrmiued. the jwrcenta;^' of nloofaol uiav be 
found by reference to tbe tabic. The epecitle gravitT is luoally 
determined in practice with a delicuto hydrometer. 

In coQiinerce aw] id the artA, the lunouiit of alcohol is usually 
expRSiad on tbe Contment of Europe in ToiuHie-pertxnlage, or the 
nauiber of lilrea of ab90iut« kIooIkiI contained ia 100 litras of the 
aqueout solullon.* For scientifie pitqMWGS It b naually expressed in 

■ In Ctmil Britaia llio vtuidan] ii p^otf-tpSrti, Tbte auii« U (lerlrM don 
tlio aid iii«iUuiil tit l«Bling i^int hj luolMoBing gunpawd*? wtth il, Md tlk«a 
I'HifiioiC tl)" iniiture Inhi oont«rt with 4 Ilxlilvd uaMli. If the atcuhol wen 
" umlpr pnrnf." th« |M>w(i*r diil not tnka Or*, but if iltBr« w»ni )iu(Eci«nt tloo- 
liol prearat, thr viiplictlioa of tli« light igoitvd Iti* ganitowdr, lli« spirit 
Itrinjc llxn '*(ivnr proof ' ^Vhnn ihr pmpuitinns of ■IcoLoI and wnter vrere 
Otioli tbai 11 was Juu pusslUle lu mi fire to the powder, tlw utnplw was d«> 
Mftbftd «• " pruaf-spirit. ' When llio iipirlt U iri>«ker ihaa proof^pirll it iS 
said b> be tijirfrr protf. ami wbro sirufif,-vr ih&Q proof-spirit Is said lo be owr 
Jtroef; fur exsiii)i1e. s xpirit whirli i* V niKler proof would contsin in mkU 100 
Tolutnes thii fsniir quautitv of Alcohol im ihol ei>iit<iood in Sft TolamMof proof- 
spirit, wul a Bpirli 5* over proof woold nnnil S vulnmna of wsivi sddod to sacli 
100 vnlunins to convert II I □ lo pnwf Spirit. B^ ad of Psrllamifnt ' proof- 
spirit '' is dcBnvd as " such a spirit as *hall at a t«IDpl^ralurt^ of 51* P wirigli 
exactiv 4} of aa rqual uieasure of distilloO watrr. ' This corrrspondn to a 
spirit oaaUininft 37 -1% €>( almhnt tiv voliimoi. or 49'3< \>f welglit.— TltAKBi.ATOik 



PROPYL ALCOHOLS, 



sr 



perociitago D^r wctghit or tlie numlMr of grammes of ntcohol cotilntiicd 
it) 100 grnramea of tlioiiqu(u>uii»olu(ioii, Thesi> ]M>ro«ntiiffe-ni)inbrre 
are iloi the Bams, becauac contraclion takes placa nh^n alcohol and 
watAF Are mixed, so that the peroentagea b}- weight are smaller than 
thiiM' by Toluiim for a spirit of aiiy ^ivvii coiic'i;iitn4lioii. 

The greater part of the uk-ohol produced in consuraed in tha 
funii of IjfVcniKws, the dftriiiifiitQl iihys'iolopcul t-ffecLs of whii'h 
nrf luigjnfutcd. by the imijuritioji, eapLtiully fusel oil, which tlifj 
contain. Alcohol is used in commerce for tlie preparation of 
UcqiR-rs, wnijiihM, dyc«, impoTtant pharma^catiail proparutiona 
(i^hloroform, clilorrd, iodoforin, etc.); it is also I'niploved for the 
jireeervation of anntnniii?j)] sppcimens. Alcohol is n good solvent 
for niiiuy organic compounde, and is widely employed in lahoratury 
work for this pnrpoee. 

On account of tbo extensive use of alcohol for inHnufacturing- 
'"JiptrWiria. ^'^'^ indiietriee in vhich it is employed would b« para- 
^lytM If the uecoBSHTy spirit were subjact to the same excise duty 
as altwhol inteuded for consiimptluu. The alcohol used in manu- 
faotiirea in kohii- niitittnes* is accordiii(;1y uiado unflt for drink- 
ing {tltnaiurttl or titolkylated) by the addition of matcrialii wliitrh 
impart to it a lauseoiia taste, and is sold duty^fcee. On ttio con- 
tinrntof £uropo cnide wood spirit is used for this purpose, and in 
Oroat Britain this is tnipidcuKintcti by tb« addition of it smiUI 
quantity of parafiin oil. 

A le»c for cthjl alcohol \» the formation of Iodoform on the add!- 

tion of loditiA ami cnimtic putmh |152). 

Propyl Alcohol*. 
4&. Two propyl alcohols un; known, onr boiling at 0"° and 
having a Bpeciiic gnivity i»f 0-804, the other boiling at 81" and 
haWng ft apeoitic griiTity of 0'78fl. In accordance with the prin- 
ciple/ whiiih Iwive heen stated, only two isomers arc poamblo: 
CH,C1I,-CH.0H, and cn.(;u{oiD-cn.. 



"TlMMleof dDi7-(r«« alntliul 1b not |>«ruillu-^ iaib« I'liiiod Sutce ; a las 
Ik leir)*d of 91.10 p»r proof gallon (So;! niooltol by volume), nr f S.07 per stand- 
ard galloQ (S31 cubic incliPB nf 94S alcnhnl l.y Tnlnrnii), sad f* a bsATj bgnl^a 
on nianv iti<lQMrt«i). Tbe duty in muoh hiKlicr iu Urcat Hriiain, Ix^ing 11«. ptr 
^tU>n iif proof .fipiril (Britiuli Miindnnl. p. 96). ti\it iIiih illMilvantagH Is In somo 
n»casari> Odonterbalaitced by Lhn salo or daty-fivo iu«tbyUU!d aplril for nianu- 



58 



ORGMHIC CHEMISTRY. 



Whif-h Btrnptare Iim to bo aligned to the laibstaiico with the 
bighpr boiling-point, and which to that with th<; lowpr, tnity he 
determinml by eubmitting the siibstancra to oxidiition. From 
each of these Alcohols ta thus obtAined a compound vith the 
formula C,lI/>, but these oxidation -products are not idonticul. 
"Mt'hcn they are further oxidixoci, the compound C,U,0 (propioii- 
uldehjde), obtained from the alcohol of higher boiling-jxtiatr 
j'icldH iin BPid (;,1 1^0, , railed propionic wid ; whereas the Kuhstant* 
C'jUjO (ncetone), oUuiined from the ahxjhol with the lowwr boiltug- 
point, is converted into carbon dioxide and tux'tic acid, C,tl,0,: 



C,H,() (propyl akohtil B.1*. ft?*)- 



»r,H.<. 



(propionaldchycie) • 



I 



— *C,1I,0, propionic acid. 

C,H,0 (iaopropyl nicoliol B.P. 81")— *C,H,0 (aoetone)— * 

— tCO, + C,H,0, iicetio acid. 

Propionic acid haii the constitution Cn,-Cn,-C00n, aiid 
acetone (!If,-C<)-CH,, aewill he eliovn later. It will be observed 
that the normal alcohol idono is capable of forming propionic 
acid, becauao the production ot thia aubstaiice must be due to the 
repluceinunt of twp hydrogou atoms by ouo oxygon atom, wtiich in 
the uoruial alo«hol can only givo rise to n compound having the 
structure ii««ign<H] to prupiouicacid. On the other hand, tlie forma- 
tion of a giibstanre having the stniotnre of acetone by removal 
of two hydrogen atoniH from a contponnd C,H,0 id only poesihk- 
when it \vm tiw constitution of isopropyl ulyohoi. The alcohol 
of higher boiling-point must therefore have the normal (tructure, 
and that boiling at the lower temperature miiat Ihi i.topropyl alcohol. 

Oxidation alTords a general method for diRttnguiithing between 
primary and secondarj' alcohols. By referring to the formnlw 
given in 44, it \» men tlmt all prinmr)* alcohols contain the group 
— 011,011, which !£ conrartod by oxidation into the carboxyl- 

group — ^^nif ^^^ L'haructorititic group of organic acida; 

further, all secondary alcohols contain the group II-C-OU, 

I 

I 

remoTil of the two hydrogen atom:) from which yields the group 
: 0, charact«ri8tic of the ketones, the homologuc« of acetone. 






BUTYL ALCOHOLS. 



59 



Tht OTtdation of a primaty and of a recondary alcohol produftt* 
Ttsptctivfly tin u/mW find a ketone with the same fiwwiftsr of carbon 
atoms as the oriffina! alvohot. 

A farther ilednction mar be miule from the facta aboTc otatod. 
It) the foiiver^iuii of normal propyl ivkohol into ]iri)|)iuiiic hvlvX, ob 
-well as of jsopropvl alcohol ittto acetone, the oxitlutiou occiin 
at the csrbou atom which \a already linked to oxygen. This 
is always the uue, and thn gmierul rule niiiy b« stated a« follows. 
\VhtH an organic couipimnd is xtihmittvd to oxiriativn, the >M(fJecvlf 
is altaektd at th* part mhtch already contains oxygen — that in, 
where OTidalion has alrradij brgiiri. 

Kortuul propvl ulcoUul it obtaiuud from fuBcl oil by fractiona- 
tion, and is a colourletu liquid vith an ii^ooablo odour. It » 
miftcible with water in all ]>ropitrlioti8. Isopropyl alcohol in algo 
» liquid; it does not occur in fuiiel oil, but may be obtained by the 
redaction of acetone (120 and 16S). 



Botyl Alooholi. 

50. Four batyl alcohols are known (c/. Table, page fil), whioh 
ig the number possible Brconling to the theory. We shall here 
cotuiider whether these theoretically possible formiil«! are really in 
agreement with the propertios of the four ieomcro. Two of the 
alcohols, thoHe boiling at 117° and 107" reepcctiTtly, yield on 
oxidation ocide with tho eame number of carbon atoms. They 
must therefore have the etnictiiros 1 and 3 (Ibid.), since tho 
gronp — CHjOH is present in both. For Teasons which will be 
referral to later, the alcohol boiling at 117^ is considered to have 
the normal Btmctnre (1), and that boiling at 107° the Btruc- 
tnre (3). A third butyl alcohol, boiling at 100°, ie conTerted by 
oxidation into a ketone with the same number of carbon atoms, 
showing that it must be a sevumlury alcohol corresponding to 
Btmcture {'Z). Lastly. thi> futirth is Holid iit ordinary tom^teratures, 
mrltiogul 25-5' and boiling tit 83". Since three of the theoret- 
ically poesibli) stnictural forintilie have been assigned to the other 
tflomen, thore runaiiia for tht^ alcohol only the fonrth, which ia 
that of a tertiary alcohol. This gtmctun? for the alcohol molting 
at 25-5^, which has been thus arrived at by elimination, is in fact in 
ttcooTilant-e with its chemical behaviniir. On oxidation, for exam- 
ple, it yields neither an acid nor a ketone with four carbon atoms. 



* 



but tho molectilo is at oiioe split up into anbstan<t«.<i oontftininf; a 
emallpr number ot carbon atoms. Remembering ttiat ao »l<;ohoI 
must contain the group ^fJlI^OTl in order to yipld on oxidatiou 
an acid with the same nnmber of carbon HtomB, and that it murt 

contain » group U-t'-OH in order to produce a ketone contain- 
ing the same number of carbon atoms, it is Dvidcnt that neither 
of Itesfl C8II be obtiilnod from a tertiary alcohol. If the oxidation 
tuVes pUici' in tliitt, a» in every other «iae. at the carbon Htum which 
in iilraaJy liukod to oxygen, it must result, in ihu duwimpoflition of 
tho mulvculo. 

What hag beon said alovo holda pjod for tertiary alcohols in 
gencrul, eo that oxidation afTor Js a mtians of didtin^iiihing between 
primary, eceondary, and tertiary alcoholN. The expcrimcntnl 
proof can be summed up as follows. 

.■( primiiri/ ah-oliol ttiehh on oxidation «« arid toith the $ama 
number of carhon aiojm; a ftcondary air-ohol tfiehis on oxidatiou a 
tetoHe with the game number of carbon atoms; while oxidation of a 
tcrtiartf (tlcohol itl onct ipUts up tk« tnoUcttle, yieldin^f compounds 
eontaimng a ai/ialJer number 0/ carbon aiams. 

Amyl Alcohola. 

01. The alcohols eoutaiuing five carbou atoms are called amgl 
alcoliola. There are eight possible isomers, and all are known 
(cf. Tabln, pagp 51). 'I'licy are liquids with n disagrt-^able smell, 
likii that of fusel oil. Isohutylrjirbinoi, (Cn,),CH-CH,-CU,OH, 
is the principal <H)ii.<ititueTit of fusel oil (47). 

One of these alcohols, secondury bulylcarbinol, affords a very 
r<>mar)ca)i1e r*iiAo nf LHomerism. Il Uaa been shown how the 
arrangement of the atoms iii a molecule accoutits for the phe- 
nomenon "f itiomcrism. A careful study of thu iiropcrties of a 
compound iimkcH it possible to assign to it a atruetura] formuLt, 
to tho exclusion of all the other formuke which are po^blc for 
its known molecular composition. On the other hand, any given 
stnieturol formula represents only one oompounil, sinc^ such 
a formula is tho expression 0/ a very tleliiiite set nf pmpiprtics; 
whcu these are utiliki; for two oompuuuds, tliis must be indicated 
by iheir structural formulat. 



MMYL ALCOHOLS. 



6t 



Nevertlielos8,thpro«re throe ieomericarayl nkohol! which li»7e 
fiecn shown by careful exnminatiou to havo the same alnietural 
formula : 






n 

OH.OH. 



Thut thcT faftTo this coiietitution in proved b; the fact that oa 
oxidation they yieltl an acid 



CH 
C,H.> 



C< 



u 

OOOH. 



the atmcture of which can easily bfi provwl by aynthesia (166). 

The three iwiiyl iileoliols with tbis cunNtitulioii have identical 
chfimieal pruperlies; their phyitieal con^tiintH aru also altnoBt all 
tbe 8Hm<.'. but one of the latter sltvcb to (lixliii^uish them from one 
auothcr. Whvii n beatii of pliuiu pularinnl ligtit id passed through 
layers of thc«c alcobole, the plauv of polarization is rotated l>y ono 
isomer to the left, aiul by the other to the riffht, while the third 
iil<K>hol prodiiceH no nit&tiun. Tbo first two are said to be optitally 
active (27. 2). 

Since the differciico between uplii»lly active compounds de- 
pends only upon a pliyejcal congtnnt, wliilu their cheminil propnr- 
tioa urc identical, it may be adk>.-d whether this dillereiiou i» not 
a purely phy»iatl one, arising from dilTerf>nc«R in the arranf^e- 
nient of the nwiectihs, eikOi se h HUppoaed to exist in the rase of 
dimorphous substances. Tliere are two reasons opposed to this 
view. 

First, diffcrcnrca in the arrangement o( the moleeuk's can only 

be supposed to exist in the cmo of idt'd eubstancc?, because it is 

oulr in these that the moleculoi* have n Eised p^mtion in relation 

to one another. It iit na^nmcd tlint the moleirules nf liquids and 

gmses we free t« movn; but tliey, loo, afford cxainples of optical 

mctEvity. In the case of lifjitidti there ia Ktill a possibility thut 

not the nmlernlea thomselveK, but con glomcnit ions of them, 

mrtnxigcd ta a doflaite manner, may he free to move. Were thus 

the cttus© of optical activity, optirally aetivo liquids when oon- 

rertod into tlie gnaemiR atatn Ethonhl, their vapour densittea lieing 

norninl, produce no rotation in the ]d»iie of polunziition. That 

tht*y nctunliy do prodnce this rotation was proved by Biot, and 

later br Okiinez. In this case the pbcuowcnou cannot bo at- 



fit 



ORGANIC CHEMISTRY. 



triliiitml to II ilifforfiiivv itt tlii' ummgement of tho molecule*, 
tMiriiuiie in n vniM>iir of normal deneity each molecule is capable of 
ibtltfiwndont motion. 

S<H<4>nd, tho optical activity sliows itatilf in deriTatirM of optic- 
ally miivit nibstsitma. 

tinniw il folloWH tliat an fjtptnnatioH of tAt tvialton of t^ 
fttaup of polaritalion in thf com of liquids atid of tUsM^vtd «iA-1 
tUncts muft he rOn^M for in ike tirtteiMre of the moUcuie* tkttM- 
Srhta. 

Tit* <nu>»lion now ariew at to wluit |>«caliarity in the stracture 
of tho mol«cult>e is tli« eaow of thi« plicnomenoii. The foUovin^ 
onn>itli>nitiiiii8 will «1iow how an jnitight may be obtained Into it 
Tho IfiV'ivlatorjf amifl lUoAotr the cnn&titulioa of vUoh has 
glran abovo m 

b ocMiwtad hy th9 action of gaaeotu hydnoclic add into «ajil 
io4idf, with th« rotutitatitin 

ClI ^ U 

Thia cMntMMind m »p4irftlly ufin. By treating it vitli naaccnt 
I H}^KY»n. tho iodino atom b rvplacvd by faTdtOfcn, with farwataon 

IN*. 




I 



If Mnyl iodtdr U nabjMtcd to the ackaoo of ctinl iodi^ is tfae 
pntaM* ft todinm. thcrr nnJtt a kfptmmt, 

ftwl Ikis Mib««aac« i» if Ufi ttfy ai*tm. 

tk«i ikifi 

!«^. U tlw Wtor iWn ai* tw» 

to U« TCHUll oai^Mi •»«. wkmM « tW < 

to tiM <«rUat afeaMi at* at < 




yAU *7 HOFP'S THEOttY OP STEREOISOMERISM. 



63 



ttiomii or groups; ami /it has litsiynated a carlimi atom so Hnktd an 
" at^minetrk" carbon atom. 

It Kaa boeu utaltid above that tliero are threi> ainyl ulcohnlB 
having the same conntitutionH] formula^ of vhich oiic in c]oxtn>> 
r«tat«ry, the «t'i-<iiul laivo-rotutory, uiid tho lliird optit-ally iniictive. 
V\in:v. siicrb iKotofirtt iilwuys fsinL in L-uiuiiiotiun with mw usymntnlric 
ciirbou atom iu thv luolcculc, and of the two optiuully active »ub- 
«tBnecs ouo causes <.-XMCtly the same amount of doxtPO-rotatinn afl the 
•other of lipro-rotation. Van 't HorKhaA shown th&t tho cxi^itcnce 
of thU ntimber of i$Mni<>r» if: a neceasiiry consequencp of the oeciiir- 
renm of one asymim-trir mrbon atom in 11 molecule, provi<Iecl 
'Certain asHumptiunH an< matlc n<phrdinj|; llio nrhitive poHittoiiB of 
the atoms in epmx. These um i\£ fulluwK. Tho tctniv»)enry of the 
cftrbon atom hiw itg orij^n iii four points of Mttraction> situatc-d on 
its oiit«r gurfnt'e, no that it is ahlc to link it>!olf tn niomg or gronps 
of aionm in font dirorcions, Coneerning th^se ciir«etion8 various 
UBUiuptions ran be mad(?. They may. for example, be suppoeed 
to lie in one plane. liut thi^t nnsumptinn iu untttnahle, ar will be 
Been by considering u (Himpoiind CU,(|,, in which It anil Q repre- 
sent any diasiiuilaratomj or groups of atonu. If the four linkiDgs 
lie in one phino, suoh a componnd may bo represented by Che 
fonuuln 

B R 

Q— 0— Q, or by Q— 0— K. 

Thtvte arc different, beeauso in tho firat (.ikse the like groups are 
Mparated from one another by tho nutike, while in the second 
oue, the like gronps arc adjapont to one another. It folUtwK fnini 
thia that in general two ii^omers mniit exiKt in the cnee of all cam- 
pciitnds C[t,<j,. Kxperience teaches that thix U not the cuee, 
beeaotK) among the many hniidrednof cnniponndAof this typo there 
is no imtance known of the occurrence of two iwomerie forms. 
Tbe particular aneumption tliat the directions of all four linking^ 
lie in the same plsne miii«t there-foru bo ulmudoued, being at rari- 
ancv with tlie fact);. 

The uiuxt general HXHumptiun that can bu made in regard tu 
thoM direciioiid is that each piiir uf tlieui lies in the same plane. 



fi4 



OKG^MC aiHMISTHY. 



They are tbeti djgtriliiitecl in apH<>e in such a wiiy that if the cArhoD 
atom be iX'giirdLHi an aitiiatcd ituidt- an irregtilar tetr»lio<Ii'i)ii, 
the directioRB of the liiikiuga will be toward the aaglei of the 

53. We shall now imcertiim whether tli is mode of n^prcseiitatie 
it) in Bticordaucc with the facte. If tho directions uf Xhv linking^' 
make diffcront ungleii with one Another, thrre still remains poedible 
n difTerpncp in tho stnictunil nrrdnijoment of coiapoiiiidfl rR.t),, 
booausr it in jiint as easy to imapine thai the gro»iM It «to oontioolcicl 
witli the HnltingR which have the rnnHlIput angle between them M 
to inia^np tlmt they lire j'mnpd with (.bosp whinh maki> the greBtea 
angle with miv another. In the case of cnnijwimde CR,Q, ihere^ 
ia, however, only one arratigoniout possible when the directions of 
the linkin^'d nu'et iit equal angles. Tkin i/t the ease whra lltf r/ir&onj 
atom 1-1 rtrjardfd us Ifing tfilt/aied al the reu/re u/ a rfgular fatir-- 
aitiNi jitfiire (Mrahettnut), leith iix Unkinff$ diiiicled toieardx the 
anylfji (Fig. 24). By putting tliL- ^jroups K and Q in diffcn-nt 
puaitiuiie in two aloiii nuidi-lrt. il id alwuys pos- 
siblo by rotating the models to briQ^ them into 
such a poHition that tho Ii1<« jrronps coincide, 
.*h«winff that tho two forniH are identical. 

This representation of the direction of the 
Hukiiigs i-xptain^ how it ib that tiieiv are no 
iBouK-ns of a iromiiouud CI{,y,. In llif em^u of 
componndH ('-RI'QS, which contain four different groups, uud 
therefore an asyiumetrie I'arboii atom, it indjcateii the ixvi»il>ility 
•if the exititenoc' of two isomerie fnrnts. It JR wen from Figii. 25 
snil '^6 (uud gtill belter from models) that for theitR four groups 
there nn:' pogsible two arrangements which cannot lie made to coiii- 
eide willi one anoilier in auy position, althoagh tlu^y rcaenihle one 
Another in the eamc way that an objeet rei^embles its reflection in 

'Tlio ranijuabi^uMiuu of wb«l rollowswill be onniiderablj- fapllllalnl It^tbri 
cnnmructlou vf eever&l iDodole ofctirbon ntt>inB witli llioir lloking*. TLis 
omtlljT "Innn by iriiilinc out a. »|ilipr« fnim » cnrk lo n-preseet tbe Mibun mia 
the llnlcliigw being n<iir«^t>nt(>ii 1i^ iiioiliiniti'lv Ihink imii wires abatit Ivn e«nt 
metres ]oii|t> tl"' ciidn or wUkli bavv l>v?ii lilwl ti; a iiuiut, Tb«M wires bi 
fis«il in the cork aplisre in llio mitniipr nlinn-ii in V'\g. £4. Tu nbovr the Unking 
iif file atom* or groupn <if aiunis, oork spiiirps of different cDloUn are (anti-ni^ct 
to lLi« hhIh of ibue iidd wlrot, tlio diBcrcnl coloun iadJcatiti^ Ibac tlw groups 
jm diMiraifau-. 




TKTKAUKnUUM. 



V^N 'T HOFF'S THEORY Oh' STEREOISOMERISM, 



65 



iv niirrttr. A figuro uf llik kind liao iiu ]iluii« of lij'mmotr^, li«rift> 
the luiiue " aii)'mmetric carbuii atom," 

Tliie ttmkM it iio(<*ib]c to undiTtfUnd liow one iaomor in jiut m 
mucb dt-'xtro-rotulory m tlic otlivr Iffivo-rotiitory (62). It. is, iu 
fact, the airaapcDK-jit of the proiips rolatirc to the Jknymint'lric 
e«rt>on mom whioli is thp am^ i»f tlip rotation of the plaiiu of 
poliirization. If the ftrrajijrcmpnt of tiie groups iu Fig. 25 pro- 






FiM. av Fi«. SB. 

ABTJUIKTBIL' C-ATOJCa. 

ducpD dextpo-rouilioii, then the iiivwrao armiigoment in the inomor 
Iu Fig. 38 must of iipce*«ity itiiiae an etjuiil rotation, but in »n 
opposite direction. 

It bns been staled above that not merely two, biit three. iHomerH 
occur vhen there is one asymmetric curboii atoui ]>reeent in tlie 
molfi'tile: a dextro-rotatory, a Itpvo-rotatory. mid an optifullv 
iniM'tive iitomer. It Ima bpeu proved ihat the optieiilly inactive 
snbstniioe i« compoei-d of ecpial partK of the dBXtro-rotatory and (if 
the libvo-rotatory rotcipotiiidd. Siure these rotations arii uquiil in 
amount, ^ut difTei*eut in direction, their eiim huH no olTert upon 
the plauo of pulariziUiou. 

This isomerism in spnce, which is ejilletl ilerfochemtea} tt&tfttr- 
inn or ftcrwisouterisiti, i» not indioAled in the ordiimry Btruclnral 
furraube, which arc written Iti one plane: hence the apparent cou- 
tnwlictioii that a Miigle etracturnl formnia may reproaent two 
different compoiindt). Van 't IIoff'8 theory, however, supports 
tlu* fundamental principle that i»ontori»ni ban its ori]i;ni in a 
diflcren'-t' in the armiigement "f tlie alome tu the molecuk'. 

In addition to die exiilHiiaiion of opticfll tsoineriBtn wliicb bra juw 
\mto given, two olliora luicbt bv nuKKcaLeil, Ijotb of whiob, livwcver, 
can be xliown lo be iitiletiable. ll iinght^ ftir example, be 8iippo«Ml 
tbnt ihe four linking of the carbon alom nrc iiucquol id value; iben 
a OORipoiinil saoli a* CPiQ eould exist in isomeric (orniii. Experience 
•hutiK ItMit ibia in uoL llw t-aae. 



66 ORGMNIC CHEMISTRY. 

It might &Iao be suppoaeil tli»L tliit plicnomenoti is iloe U> a 
dilTerenco in tlio motion of t)i« atoms in Ilie toolecule. If it w'ero to, 
iMinieriaiii could no l»iijc«r exist at absoloto aero. sEnco WoBiic ni'itioti 
eeaus nt ilnii iinint; tints « fHllinji lomprniiirn xlioiild cause a mnrked 
diminutioa in thu dilTcrciit^c Wlwwn Itiu oplicnl iM]|[ier&. Tttere ia, 
however, not tlie sligblcsl. indionUan of stiaU behaviour. 

Higher Alcoholi. C„JI^,,0. 

A4. Their propenifs Imvc alnmdy l>ecn mentioned (45). In 
additiun may bu cited cettfl ntcolmf, r^II„OlI. obl»ineii from 
spermacoti, ftnd m^ririfl ttleahal, C^^l^i.i\\, oliLuiiiod from u-ax. 
Tlitf number of i?omerg of these higher t'oinpoiiQds po^eibU' is 
very gr«at. while the niiniWr actually known is but small. Of 
the liighcT memhers of tlie series, only the normal primary coin- 
pouuds are knowu. 

Alcoholates. 

dS. Alcoholtttes nru conipuuiidK obiained from alcohols by 
exchange of the hydroxyl-hydrugeii alum fur ruetiUa (43). The 
beat known are xotlium vtethylute or Methuzidt, CH,'ONa, and 
/KMiiiim et/iylaie or rtlmxide, C\Hi-ONu. TheSf are both white 
powders, which yield cnstaliiut: compuuuds with the aleohol 
corroBponding to thorn. Thoy are eaaily soluble in the alcohols, 
and, as will b« aeon later, are fonatantty used in synthosps. Jt 
wftB fomierly mippoRod that the addition of water to a soliitioD rif 
an alcohoI»t« conirerted it compli^tely into KaOlt, and liberated 
an equivftlent (tnaiitity of alcohol: but Lokrt de Brits has 
shown that tliiA in only partly true, and thikt an equilibrium is 
reached in th« reaction : 

C.H.ONa + H,0;::^C,U.OH -+- N*«OH. 

(A proof of tbie will bo found in 62.) It follows that a solution 
of sodium hydroxide in alcohol partly doconipoeea into waUir and 
liodium aleoholate. 

Thv ulvuliolic »(>iulion of aadluin othylaic, which is usualljr ohlnined 
by dimolviiig \i\w.m at Hoditim In absolute ethyl u1cu)kiI, gmtlualljr be- 
onmes brown, iti conscquvncv of an oxidation procetts (formalion of 
flldehydc, 1U). On the otlior hand, ihe solution of Ewdtum methyUte 
in methyl nlcotiol reuiniti.s iiiinliered, for whioli rcaaon it Is much moi 
extensively uawd In Myiiibt^cs tbua sodium otliylata. 




ALEYL HALIDES, ESTEB8, AND ETHEKS. 



S6. Muny cumpoundH conlaiiiing a liyJroxyl -group fuc knoi 
ID inorganic chcmiiiitry: tbvy urc t^nlled btuuiK, iiud rcwmblql 
«ne ADotbiT cloeoly in tlioir'propcHiee. Thic eiuiilority iiukv W 
ftttribnicfi to their common po«w««on of th© group OH, which is 
proiK-nt in th{>ir n(|tiooa8 solution as An iou. 

An nqiicoTas ewhition of alcohol iloes not conclnct an electric 
current, so that the nicohol is not ionized. This also follows from 
the fact that such a sohition is not alliftlinc, and therefore contain*, 
no Oll-iona. The question accnnlinglj ariaee whether, notwith- 
Btanding this lact, the slcoboU posaeds eomo of the propeitiot 
of baaos. 

The acswer to this is iu bo far afflruiative that they are able 
to combine with acids, with elimination of water, in the same wajr 
as basic oomiKjunds: 



M- OU 



AlonhQI 



Il]-R = M-K + 110IL 

Eour 



AOid 



Those mibslsnces, which ar« comparable with the salt* of 
tnorganic cbpniiatry, are oallod cotupound ethfrs or esters. The 
tlifTprence belweitu the nature of bases and that of alcohols shows 
itself, however, iu the way in which salts are formed, which is quite 
onlilcB that in which esters are produced. The formation of a salt 
from an acid and a base takes place iiiitantaneonsly; it is a reaction 
of the ioDB, hecause the hydrog«n iou of the ai^'id unites with the 
hydroxyl-ion of the base (" Inorganic Chemistry," 86): 

(B + OH] + [H + Z'J = [B + Z'] + H,0. 

BMf A<M 8*U 

The fcrraation of esters, on the other hand, takes place very slowly, 
especially at ordinary tfiujwratures. In this case the reaction 
is between the non-tonizcd alcohol and the acid: 

R.OU + [11 + Z] = K.Z + 11,0. 

Alonltol Acid i:4l>r 

OeQcrally, ruaetious between tons take place infltaQtaneoaaly, 
those hetwet-n molemileB slowly. 

Many haaeti can lose water, with fortoatlon of anhydrides or 
oxides; so also can alcohols. By the splitting off of one mole- 



68 



ORGANIC CMBMISTRY. 



cule of water from ttro moWulei) of nn alcolioU thort' arc formed 
compounds with the geiiers] formula C,lI^.,^O^C,Uj„.j . 
called ethers; wll«ii the eliminatton of water tukw plurc bv- 
twct-n two dilTeroDt alcohok, the compouude produced have the 



general Tormula 
etften. 



C„H„.,-0-C„ 



II. 



and arc caLlod mued 



Alk;l Halidei. 

57. The alky] halidcs may be looked npon as beinj; the Imloid 
acid efltern of tli« aloohola, iw is sbowa by tJicir fonimtion from 
alcohol and 6 haloid acid : 



<'„H^.,mr 



m.\ = C„H,„.,X + H,0. 



Ill preimriiig slkyl balidea by this method, the alcohol ie 
Bitnriited with th« dry Imlogen acid, mid Lheu heated iu a soaled 
tubfl or timler a ruflux-comlensor. Tim rMction may almi be 
curried uiit by lioutiiig the alcohol with eiil])hnrii:: a.i;id and sodium 
or potOKsium halidc: 

C,H.OH +11,80. + KBr =C,II,Br + KHSO. + H.O. 

Two other methods of formation for alkyl Imlides have alruiviy 
been aUuded to (30 aud 43); those are more fully tri'sttcd below. 

Action of Phoaphorvs Jlalides on Alcuhuls. — ^These sonie- 
timefl ri"»ct together very energetically. In pre|iariiig alkyl 
bromidea and iodidca, it is usual to employ phoBphonis with 
bromine or iodine instead of tlitj hromidti or iodide of pho»phoni8 
itself. For e.tamplo, in the preparation of othyl bromide, amor- 
phous phosphorus is itddcd to strong alcohol, which does not diR> 
solve it. Hmmine is then fuhied in drope, the tempemlure of the 
liquid being kept from rising by tt cooling-ngent. i^oh dmp of 
bromine unites with phosphonts to fonn PBr, , which reacts .with 
the alcohol, prodacing othyl bromide: 

PBr, + 3(',H,0H = H(OH), + 3C,U,Br. 

The aireful addition of bromine is continued until n quantity has 
been used cnrresponding lo that required by the equiition. The 
mixture ix then uIIowmI to Ktiuid fur several hours, in order that 
the naotion may be h£ complete ikt jiOHuible, the ttnul product rt>n> 
asting rAif/fy uC phoapboroua acid and ethyl bromide. Since the 
latter boils at SS'j", and the acid is not voUtilo. it is possible to 



ALKrt HMUDES. 



H 



Btpmte thiMn br distillntton. To collect this, the flssk contnining 
the mixturu ik immersed in h water-bath heated above the t«niper»* 
tnn raCQtione<). 

It liiu juat bma metitioBM that the reaotjoti-misiurc ooii»isU 
ctiicfly of pbotptiorous actd xncl ethyl bromide, wlicranii ilie above 
equation indwat«« that ottln tlieso two aubatanoes are formed. Iteae- 
lions iu organic oheml»try are xHdoin riimutltatlro: in addiiion to ill* 
inafri rtaettou then am, in the grcKt lUAJorlly of GA»<ut, oho or mora 
MOOndar; rcAcCioas. Ttic expIniiatioD of tfais miui \» souglit in Un- 
ease with wtiicb orfpinjc compoucicU ntnier^decoDipoaition and react 
with one another. Thaw secondary r«acuaiu freqaonyy %\^9 rue ro 
tbe formaiiun of darlE-coloured, amorphous itubiitnnueft called rtniim. 
h \i seldom pCNHible to oblnin any individual compound oul of tbeiu. 
8otnetla)««, hoverer, tbokccontUry praducu of a r«a«tion can b« 
bolntcd. as, for exanipio, in ihc prongs dracribcd Abovt?, in wbicli the 
«thf I ester of phcH|ihor>vuti avid bi fomiMl along with ethyl bromide; 

PBr> + SC.I1.0U.= P(OC.U.). + SHBr. 

^H i%. Action of Halogfui on Ht/drefurbons.—OnV'j c\\\nT\Ae* and 
^Hbretnidos can he obtained in thin way, beoause iodine docs not 
^^mct nith hydnx^arbona. The method in Heldom nue^l for the 
r preparation of alkvl bulidca, eiuce, for two reamna, mixtiirefl of 
I alkyl halkle« art< obtained which are Homotimnt ver; diflirult to 
I Mparatc; whereas, by employing the other mtthodi, these oom- 
^Lwandi are produced withont admixtare of Rimilar eubctances. 
^" One of these winseJ is, thai whenever one molecole of a hrdro- 
carhon C„1I^., is broaght into contact with one molecule of 
chlorine or bromine, the rtoction dova not take place merely in 

rrdauce with the equation 

but that at the eame time compoouds C.Il^Cl,, ^a^^^-i^i <*<!-> 
are formed, a portion of the hydrocarbon remaiiuDg mucted on. 

^^ Ii U pouible lo KTOid tbs fovnatioo of Ukm higtier BubnlintHrn- 

^f prodact4 by caBstug ibe balogBiia iv nact witli tbe vapour of the bml- 
I iog bydroeai baiu. 

The other canae in that the halogen replace* hydrogen tn 
different ponttoni in the molecole. Thus, chlorine niacrta with 
normal pentaoe to form aUnDltaneotuIy primary and Mcondary 
alkfl thloridee. 
CH,.CII,.CH,.CH,-Cn,a a&d CH,.CU,.CU,.CUa.CH^ 



70 



ORGAHIC CHEMtSTRY. 



Tliia can be proYcd hjr conrcrtiug ihcao cliloridi-s into the corrc* 
'epoiicliug itlcohols and oxidizttig tlie latter (49). 

59. I'lio following: t*blo gives some of the physical properlia 
of the oi/fifl halid<.6. 






Cll. 

f.H, 

(■,11, 



Kuna. 



Elbyl 

«- Propyl 
CjM, »-rritn, biiljrl 
CtUii n-Pritn, Mu^rl 



rhiijtiilfl. 



BnlllnK- Spcctllc 
point. Onvlty. 



-- a8.:'0-9fl9(0*) 

12. a^ It). 918(8 
4fl.:i- n.iii:;;o-| 

IS- 'O-W7(0-l 

lor to.fioiLfl*) 



r 



HraRilda. 



Boiling- 
pMDt. 



Unntjr. 



4 5*1-788(0') 

S8-4- l-4tW(ir) 



ledlde. 



potnc. 



71- 

lOi* 



I ■ 583(0') 
1.806(0*) 



48' 

102- y 

180° 
15B* 



ODeriflr 



l-»U(l4-> 

I.7»6lO-( 
l-543(0'> 
I-M3t0*> 



It will T« noticed fiuik*Mil5 tTio lower ohloridea and methyl 
bmmiOu ure gunL-oiis at t&d onlinary tDaipemtttri), man of the 
otJierii buiDg 1i(|ui(](i, und the lilgheist inumbers solids. The specific 
pruvitii's of thf cliioridL-a arc in ull cusch loss than 3. and dimiiiiith 
as tlif MimitiiT uf nirbou iLtuiue iiirrwwc*. TIic ap«*ific gnivities 
of the bromides and iodides are considerably jrrvHter than V for the 
lowrKt memhero, iiUhotij;h thoj* also diminiiih with iiioreoM in 
the niimliep of the carhoii atoms, ho tlmt the hij^ht^ut tprm« of tho 
hotnnlognns Beries :ire djioclltcallv lighter than vater. They are all 
\*ry slightly soluble in w«ttT, Init dlitsolvc reutUly in many nrgniiic 
eolvGiitf. The lowest nieuiUem hiivu ii pleuHaut ethereal odour. 

Clifmical I'ruperiits. — In their Action upon silver lutnite the 
alkvl h«lide« are very different from the halidoa of the metala. 
In iiqiiivnip or ideoholio Holution the latter nt onee yield a precipi- 
tate of silver halide, the reaction being (jnantitative. On the 
other hand, silver nitrate either does not preripitate eilvcr halido 
from a solution of the alkyl hulide», or the rearUnn only take» 
place slowly. The explunatiun ie the same as. that given in 68. 
that in the Qret case the notion is one between the ions, and in 
tht' uee-ond Iwtween the molccnlea. This proves that there are 
eitlior no halogen ionx present in an alkyl hnlido Golntion, or at 
least that their miniher ia very small. 

The halogen componndfl ran Iw converted into one auoCher; for 
example, idkyl iodides run he obtained by heating the correspond^ 
tng ofalorides vith KI or Cal,. These reactions are often incom- 
plete. 



ESTERS. J» 

Tlic alkyl iodides are chiufiy uiwd fur introduciug alkjl-gronpe 
ifit« organic comfioiiadii. 

Alkyl fluonilcs are atso known, nDtt iu« inorv vol&tile ttiAti th« cor- 
nspoiidiDg chlorine ooinpnands. Tltejr oro obtuncil bjtbvkction of 
ftiUer fluorid« on an allcyl iodide, and in other whjb. 

Etten «f Other Uineral Acidi. 

80. Efltere of a great numbur ul miiienil acid« are known. The 
gvneral methods for tbutr prt-paration ar« a^ follows: 

1. Bv tlie action of tbe ai^id on absolute alcohol: 

C,H,- pH4-H] 0K0, = H,0 + C,H,.ONO^ 

AkMhiH MUic lU-U KtLjl oHrue 

2. Bj th« action of an alkyl halide on n silver wiH: 



SQ. jAg, + lil] C,iI, = SO.^C.U,), +2AgI. 

Ellijrl alllplialr 

3. Bj the action of mineral ncid chlorides on alcohols or 
■l«dta1at«g: 

The acid eatera of nilplturio acid, which are nsuall; called 

aSkyl-sulphuric acids, are of soiu» ini porta nee. Ethtilmilphvrie 

aeiil, or ethgl hydrotftn twtphaie, C,HjO-SOj-OH, is ol>tain("d bv 

mixinfr alcohol with conccntnitcd Bulphiiric siiid. The forma- 

Ijoii of thin roaipound 18 noTor quantitative, owing to the fact 

that an cqiiilibriuni is rwiched in the reaction (69). Tlie 

ethylenlphuric acid is separated from the excess of Kulphurio 

wid hy moans of thp barium (or the strontium or calcium) ealtB 

of the alkyl-Hiilphiirtc aridfl. these compmindB being eaeilv soluble 

in water, while tlie enlphativt ttri.- iimoluble, or nearly so. It is 

only neoepsary to nentrulize the mixtun! of sulphnric acid and 

alkyl -aulphnrie acid with barinm rnrbonate, the-prctduct being 

ha 
a solntion of barium othyl sulphate, p fj > SO,. The free cthyl- 

solphuric add is then obtained by tho addition of the calciilnted 
qnantity of sulphnric acid to this solntiou. At ordinary tempera- 
tnrcw it ui an odourless, oily, stronply ncid liquid. miBeible with 
wat«r in all proportions; the aqueous solution decumposos into 



7a 



OKCANtC CHEMISTRY. 



eulpliQiic acid and alcohol, elowlj nt the ordioar; tcmpcruturc, but 
quickly wlion heated to the boiling-point. 

Tlio iMiriuR] s&lu of tbo Hmylsul|>1iuric Aoids, obtalued from tbo 
Mtij'l alooliols Hod siilpharic luiid. have diffcrrnt solubilitiofi in w«tcr, 
imd can be partially sepanUed by fractional orysUillizatiou. Bf tiiis 
iscaiia Pastbdh wu Rl)Ie U) aeptirate tbe optically a«iive adi}' alcohol 

from Uobutylcnrblnol, ^|||>CH-CK,-OH,.OH, both of which nn> 

preacnt iti thti mixture of amy) nicoliola boiling at ISI'-IUS* obtajiit-d 
by lli« frnctiuual dislillnlioti of fusel vil. Isobntylcarblnol is tlii> cbirf 
eonttitueDt of the tnisture of amyl nlcohots boiliug at this temperature. 

Ethylgulphiiric npid forms well cryKtnlliwd wilts; its pota«8iuni 
salt ie need in the pr^piiration of ethyl cnnipmindR. For example, 
ethirl bromidfl n reiulily prepared liy tlio dry distUUition of u mix* 
tlire of potasfiiiim hrnmido and ]iotai»iuin ethyl HuIphHte; 

K0-SQ,-O|C, U74^Bii K = K.OSO,-OK -h C.H^Br. 

■"OIBHl Otllj) • PlItHMlUIII Etltrl 

•iilplikili iriilphaM broiriiilf 

When frwj ethylfltilphurie acid is heated, the neutral uthyl eater 
of Bulphuric acid and free sulphuric acid Hre formed: 

OC.H. , o» OH ^.» OH . „,. ,OC.H 



SO. 



<oif * + '*«.<oc.u, = *'**.<0H + s«><oc;h;- 



Estera of the fallowing minernl acidaarc also known: hypochloroas 
acid, poiNihlorio acid, sulphurous acid, <iiilp)iurio acid, hypo&itroua 
acid, nitrons acid, nitric acid, pboitpburous acid, liypoptiusplionc acid, 
pbosphoric acid, aracnloug acid, arsenic acid, boric acid, and silicio 

aoid. 

SaponiflcatioQ. 

61. When esters are hoited with dilute anids or alkalis, or 
when heitted to n high temperature with wat«r, they decompose 
into alcohol and acid, titkin^ up one molecule of water. This 
proceaii is cjJIed " BupouiHcation," hecauau it reficmbles the prep- 
amtion or Hoa]i from alkali and fiit (91). The formation of an 
Mter iioui an aloohol and an aeid is called eitertficaticn. 

Etheri. 
63. The eonetitutiou of these compounds, which are isomerio 
with the alcohols, is proxed by Wiluamsos's Bynthesiii, the action 
of ftD ttlcoholutu on an alkyl hiitiile: 

C.H^,.01KmJ .C„,H^.. = C.H„„.O.C,H^., + N»I. 



BTHEHS. 



73 



This synthesis affottlB confu-mation of tho conBtitutJon of the 
alcobolates indicated in 43, tluit the metal occupies the place of 
the hrdroxyl-hydrogon. Fur. supposing this were not the cuast 
and tliat the metal had ropIftL-tnl u liydrogon atom dirt^ctly linked 
tu varbon, then sodintn mcthylato, for example, would hare the 
formula yaXHj-OH; this would jiold propyl alcohol when 
treat«d with ethyl iodide: 

CH.OH = C,H,.CH,OH + Nal. 

TbiB reaction does not take plftc«. There is prodnood inetoad 
methylethyl ether, whirh has the empiric-al foniii.ila of an alcohol, 
but none of its properties. 

WitxiAMiv>.v'9 flyntb<?8iA is also pos^iblo when the alroholate is dis- 
solved in dilute alcohol (JiOJ), Though «o much waler is praspnt, the 
T«actii>ii is aliiicitti a qiiantiuttivconc, from which it follows tltat the 
greater pnrt of the sodium alcoholAte raiut ba pro«ent as such, and 
tbtrefore is aot dccomixued by tho water into alcohol and nodium 
hfdrate (55), becaufie in (hat caB« tfa« (onnaijon of ths ether would 
neceuarilj be prevenud. 

63. The beat known compound of the honiologoas Beriea of 
ethers ig the diethyl ether, 0^11^-0-0,11^. whieh ia usually called 
tther. This compouud i» maiiufuctured. and uIho prepared in the 
laboratory, from aulphuric acid and ethyl alcohol. For thia pur- 
pose a mixture of five parta of alcohol (90*) * ia heated with nine 
pAita of concentrated itnlphnrie acid at laO'-UO*. Kthcr and 
water ditilil over, and as iionn an diRtillation hoa eominenced, 
alcohol i« allowed to llnw into the di.>itilling-f1nsk at such a rate as 
to keep the volume of liquid in it c-onstant. Kther pa«t)e4 con- 
tinually orcr, but after about Rtx times a« much alcohol hag been 
odd*^ as waa in the fimt inntance mijtC'd with Ihe sulphuric a<rid, 
the dietillate Iwcomes richer and richer in alcohol, until finally 
the fonnation of otlior 8to]i8 altogether. 

The oxplanation of this process is as follows. Tho alcohol and 
salpbnric acid in the first inittance form ethylmilphnric acid (60). 



*Meili5laiMl *plrit ta»,j be snlntUaied for pun splrEt, the product belof 
aallad " iDeUirUtnd otlm-"— Tbakujitok. 



74 



ORGANIC CHEh4ISTRY. 



When ethylmiliiliurio Rcid in honted with wntor, it u aaponified, 
with 7«generntioii of the acid and alcolio]: 



C,U, O.SO,II -h H (OH = G,H,.OH + H,80.. 

When, however, iiistefid of water, ethyl fllcohrtl reacts on ethyl- 
salphnric acid, ether and sulphuric ftcid are formed in an exactly 
analogous manndr: 



The production of other depends apon tlio fortnatioii of cthyUul- 
phuric acid, and eiibseiineut decomposition of this compouud lulo 
ethyl ether and sulphuric acid by the addition of more alcohol. 
Since th« aulphuric acid is a^raia formed (regenerated) in thia 
reaction, it yiulds a Tretih qiuintity of etbyliulphunc acid, bo that 
the ])rocc«»! is a coiitinuouH one. This would lead to the expecta- 
tion that B smalt (juuritity of milpliuric lu-id wuiild W alile to con- 
rorl an iiiilimitinJ smoiint of alcohol into other, but this \b not 
lioruc out by i-xpericacc. The explanation i« that bi the forma- 
tion of ethylsulphuric acid from alcohol and Btilphuric acid, water 
ifl formed as a by-prcxluct: 

C.H,i OgirH SO,H = C,H,.SO,H + E,0. 

Thifl water partly distiln over along with tho ether, bnt partly 
remains behind in th« flo&k, decomposing thu ethylsulphuric add, 
as soon as it is formed, into alcohol and tiulphuric ucid. When 
the amount of waU>r in tho rotLctiou-mixture exceeds a <^«rLain 
limit, it provonts ihu fonnariou of ethylsulpliiiric acid altogolher, 
and ill tlii« way puts an end to the production of other. 

When another aleoliol is allowed to flow into the original 
mixture instead of ethyl alcohol, shortly before the diatillation 
begins, a mixed ether ie obtained: 

CA1 ^0«H + H tO-C,H..=C,U,-0-C,H.. + II^SO.. 

This is a proof that the formation of ether really tak«s i>Iaee in 
the two atagi-a mentioned above. 

Thv crude ether oblainiMl in this manDcr coolains water, alcobol, 
and sni:kl] ((uuiitititw nf siitpliiii- diuxiiio. It is left iu contact nitb 
quicklime fot- sevoml days, llic wAior. Kiilphar dioxide, and part of th« 
aloohut being thus rcmDved ; it is then distilled from a vtMr-bMta 



ETHERS. 



75 



I 



bMlAi to ubimt SA'. To remore lli« small <itiatniiy of alcohol rcmatii- 
lag. it i« sli»kcn up scTenil times with small Tolnmwof nitXer, and the 
wat«r niu oil. The ether is iwfwraipd from iJiMtolveil wal«r hjr dl^ 
tilUition, 6nl orer calcium chloride nod llnitUy over lodiuin. 

Diolliyl ether n a oolonrlees, rery mobile Hi^uid, boiling :it 
aS'l", and soliiliryiiignt — IlS-l". It hu^an a^ewible otlour: pro- 
longed breathing of it [irodiicet) uiti^oniurioueinusii, followv*] by but 
filigbtly disagrtivablo coiiacqaoncoa on nwakoiiiug. Ktbcr U tiion?- 
for« useii in «urgcryag nii atitosthotic. It i» slightly soluble in 
water, oiio volume dissolving in n*l volntnes of watvr nt 35°; on 
the otlwr hand, wnter dis^ulveg slightly in ether (2j( by vohimi' at 
12°). On account of its low hoiling-jioint, ether is very volatile, 
and aa it« Tapoitr is highly cnmbaetible, burning with a luminous 
lliiuiv, and producing un exploeivo mixture with uir, it is a subatauoe 
wbtdi mnat be very carefully handlGtl. IntoDiio cold ie prodncod 
l)y its evaporation, the cuteido of a flaek coutjiiniug it b4H.'ommg 
cxMtted with iec whon thv t>vft[iorntiuu uf tho ether is proniotud bj 
tfa» iutroductioii of a rapid atre-iim of air. 

In the laboratory, ether ia an invaluable solvent and cryatullis- 
itif^-iuediunL for many compounds, iu addition to its uite for ex- 
traotuig aqneoRs aolutions (St4). It is also of great utility in many 
niaii u ra<>tii rtn g-pmnessoe. 

Homol<^es. 

64. Dimethijl rihti\ C'II,-0-C'lIj, is nMained in the same vay 
a« ordinary etbor, and is a ga« liqHcfyiug at — 2U\ Tlie hi^or 
horaologucs are liquids, the highest lioiug solid crygtalline stlb- 
stanccd: nil Iinvo a iipccific gravity considerably Ie«e than 1, the 
majority Iwtween O-T' and 0-fi. 

The ethers art- comparatively ulablti towards rhemical reagents. 
Dilute acids, iilkiilifi. and plioHphoniH jientjirhloride have uo action 
on them at ordinary tempc-nilureii; sodium it? tiuablo to displace 
nny of their hydrogen. When, however, they are heated with 
haloid acids, halogen componiidtj arc fonii(>d. In thin wav 
gaseous hytlriodic acid, when j>iL^S(td iittu an elhv<r at tbi> ordinary 
teiujieralure, prodtic-es alrohol ami alkyl iodide: 



76 ORGANIC CHEMISTRY. 

at higher temperatures water and alkyl iodide are formed ; 



C„H,„,,0|.C„H,„ , + |3H 



I = C3,n„I+C„H^„I + H,0. 



Isomermn. — This may be cauBed, aa in the case of the alcohols, 
by branching of the carbon chains, by tbe alteration of the position 
of the oxygen atom in the molecule, or by both causes simiU- 
timeoualy. y 



ALKYL-RAIIICLES LINKED TO SULPHUE. 



65. TIiOM elumeuU wbiuh arc grougicnl !ii the same column of 
tTip periodic Bystem (" Iiiorgatiit: Cliuuiwlnf," 311-831) yield 
similar (.■oiapouiidzt. a fact tmccablo to tboir liuviii^ cfjuul vulviiciutt; 
they furtlitfr rcKi-ni))Iti one another in tJioir chemic»I properties. 
Expcrienco lins eJio^v-n thiit orgfinic compounda contaiiiiu? elements 
of such n group display the properties of their inorgiiiii<? unnlnguea 
in every rnriet; of aimilurity nnd diEuimilnritj, th^ir points uf 
reMmblaiics anj of flifTerenfo being sometirae-i ctwh iiu)r» uiarXvcl. 
than those of the itior^iic compounds. A oomparinnn of tlio 
oxygon compounde, which huvo been di-alt with up to tUis poiot, 
with the sulphur compound* of eimUnr etmcturo, vill servo m on 
example of this. 

Tlie alcobolg and cthora may be regBTrled iw being derived ' 
wnter by ibe re]>lac*'ment of one or botli nf its liydrngen at 
alkyl. Tbo corresponding snlplmr romponnds arp dpriv. 
■same way from sulphnretted hydrogen; they are reprt-" 



c„H,„.,.sn 



and C„n^.,.S-C, 



Tho firat are called mertutptanf, and the si 

Tbe resemblain'w of tboM) conip""" ' 
ii chiefly notirt-able In their mo' 
huteod of KOU reacts with 
formed : 

1.V 



ers. 
aols and ethers 
-alion, for if KSII 
.iklidv, a murcuptsn is 



1U,-SH+RX. 



The property poweKJ 
atom iti the luoU'ciili' 
ToptacTJiblc by metals 
rGBAonnblc to etipp< 
irom all the others, 
atom* being linlceil ! 

Jntit lu tbe «!' 
olrobolates, so tli. 
compound!) of the i 



•iV-obols, of having one hvdrogen 

ibliud from all tbe others in being 

luud in nicrt-'aplauti. It in therefore 

:■ c bydro(,'vu atom, thus diKtinguishod 

. to flulpimr, the rert of thv hydrogen 

dunned by tfie action of alkyl halldee on 
rs ure obtuincd by treating tbe metallic 
fius, tho mercuptide^, with alkyl halideo: 



an^M-sj^ ; n^M = c.u.,...s.c„ii,„,, 4- nuI. 



7? 



ORGMMC CHEMISTRY. 

Water is a uontral compound, and sulphurcttod hydrogen is a 
u'ouk add; oorreapouding tu thlo, ulvohol does not form &lcohol&te« 
with the hasen of the huavy motaU, while mi>n>jiptanii ytold luercap- 
tides u-ith ihtm. An ulcubol sucli as uniy] alcohol, which is soluhli* 
with difliculty in water, dot-it not dissolve in alkalis; but the 
mercaptan«, which nro all iniM>luhlu in wutur. arc on the other hand 
easily solubW iu alkalis, with formation of murcaptidoB. Tbey 
tbereforu pussL>8S au avid viharautor. 



UtrcaptauB. 

66. In addition to the methods of formation already mentioned, 
mercaptonH con bo obtained by the action of phonphorus pento- 
enlpbidc upon alcoboU: 

5C,H,„ . , ■ OH + P,S, ^ 5C.H„„ - SH ; 

>'r by distilling a solution of potassium alkyl auljdiato with potas< 
'vdrogen sulphide: 

u,'Q -8o,K + g^ 8n = c,n,su + K.ao,. 

They ar. almost ineobible in water, with boiling-point* 

markedly lowv.. i those of the corresponding ulcohotfi. Thng, 
meihgl menafitaH ■*'\-fl.t (i", methyl alcohol at 88°. They are 
chnrncteriaod by tbu , — loA^ion of au excMdhifflif diuiffreeablt snitU, 
which thpy havu in coniiat ■"i"'i almost all volatile sulphnr com- 



pounds. Our organs of m : ' 

and can detect the morost tr 
slight nti to bo qutt« unre^ogniz*, 
Many metallic compounds of 
of them in a well eryetaliized fo, 
fnniiiib an exaniplo of thoso bodios, 
of nien-ajjtaiu on mtfrcnric oxide, k 
pounds is dorirod (by shortening eorp 



very sensilivt' to mercaptans, 

them, even when they are so 

rrbeinical means. 

■n-aptiins are known, some 

I'ho morcuTT meroaptidos 

are produuod by the action 

i< the name of these oom- 

ercurio aptum to w«r- 



caplan). Many of the other hemy t.h ,'.i. such as lead, cnpper, 
and biamoth, yield mercaptidos; tbe 1 " ^"i pounds hare a yellow- 
colour. The tniTcaptun id sot froo Irurti idl niercapttdea by thd 
addition of mineral acids. 



iERS AND SULPHOHK ACIDS. 



7^ 



Ttiio«tb«n, 

87. In addition to the methoiln given In 65 for the preparMioa of 
tboM coatpouiids, tbc action of polnssium sulpliidd, Ki^S, upon the 
siiltB of alkyl-sulphiirio icids laajr be employed : 



'>SO, ftr* formed by tba oxidation of 



acH. [o^.K ■¥ K. [ 3 = (C,nt>.a + 2K.8O4. 

folaaaluRi 
Plliyl lulpliato 

The Uiioottiors arc nDuLral compounds nfth an oxcoedlngty offan- 
ftire smelL They are liquids insoluble in wal«r, and yield double com- 
poDods with melallio ttaita, e.g. ((J,Ili),S-Hj;;C'li, 

The roercnplans rc-jioinbic sulphnrQtIcd hydrogen tn boing slotrly 
oxidiiod by C'unlact witb iiir, whcrvby tb«y aro courcrted into disul- 
plitdus; for exft&i[il«, dlothyl dlsuljiliide, 

U«relh« bydrogfn nhicli is linked lo^ulphnr iSTemovedbyoiidation, 
so that the disulpLiidcs liaro (ho constitution giren above, tlie proof 
of this being tb.it Ibey aro ^<o oUaiued by beating potassium elbyl 
sulpbate with K,&.. 

Nuinernnft compoandx containing oxygon and milpliDF occur among 
inorganic bodies: tubstanoce of this kind are nliolcnonn inorganic 
clieiDisIry. 

The suiptioxidtM, H"!!'"^': 

tbioelhers with nitric acid. Their conititiitlon Is Indicated by th<> 
fact llmt tbcy are very uiwily reduced to thiocthcn. If the oxygen 
vera linked lo carbon, Khev wouid not behave in this manner, becanse 
uvitber aloobc^s nor etlien lose their oxygen by gentle reduclion. 

I^ It 

The »uiphotut are compounds irith the constitution ,,"1] " ' ' > SOa, 

■sahown in U, Thty ai-e formed by strongly oxidizing the tbi««tb«rs, 
and alto by tho oxidation of sulpbotiden. Naacent faydrogeo is 
UBftUe to effect their reduction. 

Solphonic Acidi. 

M. The nUphnnic acids rosalt wlacu niercaptaRfl nndetgo vigorous 
oridalion (with nitric »ictd>. They hare Ilii- f<inmila 0«lf,n.- -SO.ll. 
Tbo alkyl'group rcnutins intaot during this oxidaUon, for tho salt« of 
tfacM salphonic acids are alao formed when an alley] iodide reacts with 
» DU]phit« ; 

CiU. rrn^ so.K = ki + cd.so.k. 

Sinoo the Bulphtir In mervAptana is direetly linked to carbon, the 
•ame.botds good for (ho stilphonic acids. Thla ia furlbcr proTcd by 



8o 



ORGANIC CHEMJSTRV. 



tb« fnct that lh« latt«r ytftld mereaptaas on redoetion. The itrnetim 
of ethylaul phonic acid it tbereforv 

CH,.cn..so,H. 

The group SOtH miul eonuin a liydrosjl-group. bccaiiM PCI* 
7l«Id8Witba sulplionic acid a compound CBlIn,i-SO*Cl, from whicb 
tbe sulpbontc acid uay be reKfiueraied by t\w nctioD o( water. Tba 
»tro«tureof the compound i« lhcivforoCIl.CH.-SO,-OlI, wjuch Icayea 
it Atill doubtful whether tbo group SOi contained in it bas the stroctnre 



O O 

8< I or S^ ; 

o 



that la, wbetber ths aulpbar Id aulphoDlc acidi is 



totrnvnlont.orlicK.^vitloRt. Thoidlcyl-siiilpltonioflcldit >ro Btrosglf aeld, 
Tory lijgrowiipic, erystalllno sub»(Rii'Cea, and rery soluble in water, 

la the ttbovo-ineritioiied couipounds C„ll,„.,-S<.>tCl, caIImI ntl- 
ptionic chlortdta, chtoriiiu ohii be rrplacwd by hydrogen when it acta 
on thecn in the oascent ctato ; tlio bodies tbus ob<aiii«d have iha 

formulH CnTI,n-.-S,j', and are ciillod ntlphinh acuta. Wlieii an 

allEyl halido roiicU with tku iwlium sail of a auiptiioio acid, a aal- 
pbooe is formed (67): 

CH..S*J.^ j-CH, = J^*J[>SO, + SaBr. 

This modo of ptwparntion Is a proof of Hid cotiEttilution of tbo snt* 
pboiics. 

Atinlogoua aileniuin and tellurium compounds aro known, cor- 
respoiidiog lo tbe majority of the Aulpliiir compounds jual described. 
Theae also liaTit a most oflTeusiTe BmsU, 



ALEYL-RASICLES LINKED TO NITROGEN. 

I. &MIKBB. 

69. At the beginaiQg of tho prcrioua section (66) it is stated 
tbat the propcrtiwt poeaciasL-J hy iaorganic cumpouails are even 
mom marked in their urgonic derivatircs. I'hu uompounde tu he 
described in this acction afford another striking cxamplo of this 
phenomenon. 

The tfrm amines is upplietl gencmlly to siibstfliicoe which majr 
be regarded ai derived from ammonia bv exchange of hydrogen for 
aUcyl-rwltclee. The most chnrarterislio prnpert-y of ammonia t8 
its power of combining with acids 1o form salts by direct addition: 

Trivalcnt nitrogen iti thereby made pentaralent, a chango ap- 
parently intimately connected with its liasifl rhnracter. TbU 
property ia ulsu found among tliu nlkylamines. They arc, at leu«t 
those low in the ocrivs, bctt«r conductors of electricity, for the 
same niulecular Louccnt ration of their aqueous soliitiono, and are 
therefore more Btrongly basic than nmmonia {" Inorganic Chem- 
istry," 66 and 236). This applioH aliM) to the organic compouuds 
corresponding to NII.OM, ammoniwm hydroxido. The laet- 
nnmed uibetance is not knovn in the free etate. but it exists io 
tJio nqneoos aoliition of ammonia. It is very unstable, being eom- 
pictely decompOEied into vrator and ammonia when its (tolution ia 
boiled, it has only veakly basic properties, because there are 
bat few Nll^-ioua and OH-ioua in its aqueous solntion, apparently 
beoause the compound NU,011 has a Tory strong tendency to 
bnwk up Into NH, and H,0. Siich a dccoDiiK)«ition is. however, 
no longer possible for compounds containing four alkyl-groups in 
the place of the four hydrogen atomt) of the NIT, -group; esperi- 
cDce haa shown that these compounds possess great stability. 
Since Ihe nitrogen cannot revert to the triralent condition, 
their basic character, in comparJBon with tliat of NH,OH, is so 
strengthened that they are ionixed to the same degree as the 
alkalis; they are almost completely split up in Dolutlona whose 
dilutiou u tJ-b of the normal. 

The amines yield complex salte fully analogous to the ]>latinum 
Mlt. (NHJ.PlCl,, and the gold salt, NH.AuCI., of ammonia. 




AMINES. 



H 



f^wlth tho alkyl lutido, Yielding the halogen salt of a quator- 
nar; ammonium bsisu: 

It is oBsumod in the foregoing that excess of ammonia is 
employed; but oron vhen this is not the oa«e, and in general Cor 
every proportion of nlkyl hnlido and ammonia, tho r«action tnk«g 
place in theae four phases. The final result is, tlierefore, tJiat the 
primarr, wcondary, and tertiary amines, and the ammonium base, 
are formed together. It is often possible, however, bo to adjust 
the pro{>ortioQ of ammonia and alkyl halide, together with the 
dnration of the reaction, etc., that a giren amine is the main 
product, and the qiiantilies of the other amines are small. The 
nature of the alkyl-gruup also exercifiBS a great influence upon the 
character of the rwicl ion-product. 

Tilt! separatioji of the mizfurf o/ tJ mines fo ohtuincd Ik often 
difficult, there being no method getioraily a)>i)licable. The i>cpara- 
tion of the ammonium bases from the ammonia and amines is 
cimpte, because while thfc aminos are 1i(iiiid» rnlfllilizing without 
decomposition, the lower nienibers being eren gnses tiie am- 
monium bafiCB ant not volatile. When, therefore, the mixture of 
thr amine hydrohalides and the ammonium ba.<ieR is distilled after 
»dditioii of caustic potneh, thn frre aminefi only pUBS over. 

In order to Boparate tho primary from tho mixture of the 
hydrohalidet? of the tliree aminos, fractional cryntallixatioD is 
hirgely made use of in tlieir preparation, at le««t in the caeo of the 
loiggft memhera, methylamine, dimethylamine, etc. The higher 
"''^''ceoafc l>egimiing with the propylamines, can be separated by frac- 
tional distillation. ' 

YatiouE methods of preparing primary amines unmixed with 
aecondarr or tertiary are known (88, 104, 244, 254, and 388). 

The veiiM-'ilif of the forrnnliiMi uf letraaJi-t/hii/ttriojiititit^ iodides 
from tTiethylamine and an alkyl iodide or bromide has been iuvee- 
I tigated 1>r Menschutkin. U is apparently a MmolectiUr reaction 
[("luorganiv Chemistry," 60)i and therefore taltes plaoo accurding 
[to the equation 

dx 

-wboTe 1 is the Teloeity, k the constant of the reaction, a and h the 
qDonUtiec of amino and iodide by unit Tolume expressed in mole- 



AMINES. 



85 



taristic odonr, and are slightly Bolullc ui -water. Tboy ow taxQj 
reconverted into B«coQdarj iiminc« bv the iiction of concentrated 
bjdrochloric acid (285): this u n prnor of the tttructure givoiL 
aboTe, because if the nitmso-groii]> weri> dimctly linked to h cnrbon 
atom either Itr itH oxygen or by itH nitrogen, it would not be 
poaeible thus to reoonTert it into u Bm-ondarr amino. 

Tertiary uniinv« are unacted upon by iiitrouis acid. 

Their behaviour with nitrouB uxiid i« therefore n means of dis- 
tinguishing the three elassea of amines from one another. It also 
serves as a hasiB for the eepanitioii of the secondary and tertiary 
amines in the pure state from a mixttire of the two. When a 
concentmtcd whition of aodinin nitrite is added to a hydrochloric 
acid solution of » mistnre of the {.uo amincR, the Bccondsry amino 
is converted into a nitrosamino, vhieh eollocta a« an oily layer or 
the mrfaee of the atjueoun Kolutiou, and can be romoved by nionjis 
of n eeparoting-funnel. 'l*hti tertiury amine l* not attaekod, but 
remains in the aquooua solution in the form of a salt; it ean be 
obtained by distilling with caustic potaeh. It ehould be mentioned 
that any priuiary auiiue vhich may be present is decomposed 
during the procees. 

Another method of difftingniahing between j)riiiiary, seeoiulary, 
and tertiary amines conslstei in the determination of the number of 
Alkyl-gruupg with which the amiin.' can eoinVmc. For example, if 
a compound t',U,N ii projiyUmim*. C,H,N 11, . it should yield, when 
heated with excess of muthyl iodide, a compound 

C.H, 

Blionld yield 



^•■''Ni = ('.H,.Ni; 



if C.n,N-=<g^.>KH, the 



8nme treatment 



^^\ ^'I = C,n,.NI; kaUy, if L'.ILN = (CH,).N, there would be 

ohtainwl (CII,),NI = C,n„NI. A titration of (he iodine ion of 
the quaternary ammonium iodide formed ie KuQicicut to determine 
whether C,n,X is primary, secondary, or tertiary. 



Individual SletiiberB. 

73. The lower membere arc infiammablc gases which are very 
•olublo in water; thne, U50 volumes of methylamine dissolve in 
one volume of water at IS'S". Tlie sucoeeding members bare low 



Ifttt 



B6 



ORGANIC CHEMISTRY. 



boiling-pinnU, and arc mieoiblc witlt wiUvr in all proportions. Botb 
tlivv a\A thv low«et mcnilxirs have a oboractehstio ammoniacal 
ein<>ll, like boiled lobstont. The highest members nrc otlourloiw 
and itiiiolnblo in water. The apeoiSc gravities of the amines ere 
nppieriiiHy less thiin 1, that of methrlaminfl being only 0-690 
at — 11". Tlifl following tablo indicuics tho vuriationa of tboir 
boiling- pointB: 



Alk;l-IUdii^. 


FrtwatT- 


SnRoadj ry. 


TBfitti-y. 




— fi" 
18° 
«• 
76' 

180' 


r 

1«0" 
S9T 


8.r 

fiO' 
IW 
215* 

866' 

















Methylamine occurs in MercuriaUs ptrenriu, dimtthylarmne. and 
trifaetkylatnine in herring-hrino. 

TelramtthylammOnuim /ii/droxide h obtiuneil, liko ail its homo- 
logitee, by treatment <>f its lialoid acid salt with moist aiker oxide, 
Ag-OH; it ia a whito, L-ryntallino mass, sthI U very liygroecopic- 
It is ilecomposwl by he«i into triraHtbylaminu and methyl aJoohol: 

(Ciu\-on = (Cig.N + cix,on. 

The higher ammonium boaee are converted lij heat into a tri- 
alkyliLQiine, water, aud a hydrocarbon C'„1I^: 

(C,uj,N.OH = (p.n ).?r + o,rr + n,o. 

The Btnicluro of the ammonium Ijasea is thntt explained. The 
nitroften atom is the only one in the moleculo which ia able to 
linlt itself to the four monovalent alkjl-groupa, and to the mono- 
valent bydroxyl-groiip. It must bo assumdl to be peutavalent in 
tbese oompounda. and tb« couBtitutiou of the iiuunoniiuu bases is 
theroforo 

in which n, m, p, and r nuty be Hko or nnliko. 

AIkyI-d«riTAtlre« of hydraritu or diamide, TT,N-NH„ are abo 
known. Among tlie methods for their prepamlion may bo mentioned 
tlie direct iotroduetion of aa alkyl-gronp into hydnutioe, and the car»> 



AMINES. 



St 



fol redaotloQ of nflraeftmiTiM (73). Tlioy bare Hllle power of rasist- 
aceo tonards oxidizinK-ngents, an alknline copper Boluti»n, for 
ezample, tNjing reduced t»y them at the ordirmrj- lemperatnrft. 

74. Triefhytammf u soluble iti wiitor, aUliougb nL about 30° thu 
solution Beparaira into two layow. Thw upper of tbeae voiisisU of n 
BolutioQ of valrr in tho uniitii-, nntl the lower of a aoliitioa of tbe 
Amine in water. Iii tbe neigbbourbood of 30* n slight nse ia temper- 



nt 






3* 









t 'ii)'w'»'il>'iDgbA>' n'^ 

Flo. ST.~-$OLl-])ILITT CUMTB r«lt Tlt»ILTUYLA>II»tt UID WATn. 




« ID it M •> Ml ' do ^ a> n iM 

TtartlUTulM 

FlO. S8. — U9DAL FORH Of Bol.rBlI.ITY CCH'»-B VOK TwO LlQClOS. 

klure id able to tftvei tliia separation into tno layen, merely boldioif 
tbo Inbe for a moment in tljit warm li^nd iHiiii)^ sufl1(!l«nl. 

Why tbia Miper&tion takca plucc, and nl ^'bnt Iciupcraluro, » moat 
eaailf nndemtood by u cotisidpratiun of tlie cttrra of suiubilily of the 
syatau auune + water. This ammo (Fig. 37) is leas tolublo Id waroi 
vater than m cold, and below 20' is mtncible with water in all prapor- 
tious. If, for example, iiicreaainK quantities of the amino be added to 
vater at 30*. it diuolves until the amount ot acuino re-.icbi» about 5f 
tCf. rig. S7). Th« solution in thou siituratcd, and addition of mcr« of 
the amine produces a second layer of liquid. On the otiier hand, kLvd 
vater is added to trImotliylaiuiDe at S&", it dtsaolves until the aotoiiDt 



88 



ORGANIC OitMISTRY. 



of water naclies aboul SS \fif. Fig. 37>; twyoiid (liU point ttro layers 
nni tonnod. Tlio line DCis I ho eolubility curve for water tliMolvcd in 
trimetbylamine, and the line AB that for trimelbylamiuc in water. 
When tlie [ciiiperaLune fall^ tlie solnbllity of tli« irater in tbe amine 
lacranAca on the one linnd, and on tlio oihor, that of the amine in tbe 
water, so ttiat Ilic eolutiilUy lines mcot one anotbor bolwecn B anil C. 
Tlie whole area is liieo dirided intw (wo parts by the solubility I'urres. 
All the ))olnta within i1 ffCZ> carresfiond to two layers of liquid, and 
nil tliD poinis oiitRide it to a honiog^nooux niiilure. 

If, fur ciumple. the nbscissA PQ is drawn for n mixturo of SM of 
amino and 80<of water, lii« tnizture is homogeneotis for all lemiwr- 
aturos U|i to tlio paint if, and Iietorogenoous abore that temperature. 
Along tlie very .it4>ep portion of the currc, repre-iented in this epeoinl 
COM by the iiurt. BC, a sliglil rise la temperature must evidently r<«iiH 
In sv|inmtioii of IIk> liituiil; because although at ab<^)iit SO* Mho )t«>liit K) 
two lifjuid layers are just about to form, of wbicb tlio aqueous Uycr 
would conlaiii 2M ot amine, at R', oorresponding to an ineresse of 
teniperntureof IfiAs than I*, the lalttT coiilitiiis 60^ of amine, when tbo 
Ii(]ii<<l« tnitgl Koparalo Into two layers. It followa that in this pari of 
the curru a einiill rise of tempLTaluro must cauao a Ec|)aratiou of wiilcr 
Buflleieul to alter Ihti oompoBiliou of one of the layers from 30]( to WK 
of ami I in. 

It liofi biicn already montlonod that the rolalivo solubliiiycnrvc for 
the system watt^r -f triolbylumiiia has a B|)ucia] p»th in the iiortiou 
SC. Tbo wholo ourvo dilters, liovovor, from thoso ohtalnod In ordi- 
nary cases. Tbo Bolubiljty of liquids which nro partially misclblc with 
one another usually incTeases with tbo temperature, just as in the ease 
of tiolida and liquids. Thu eurvv ia tborofore exactly rereraed) so tbat 
It it usually as reprMeutiKl in Fig. 28. 



II. BlTBO-qpMPOOinJB. 

76. 'Wlien ailver mtrite ruacW with au alkyl iodide, two com- 
pounds are formed, both of which hare the empirical fonnuU 
CoH,„i,NO^ They have diftercnt boil iug -points, there being 
obtAincd from ethyl iodide, for example, a substauce C,H^NO,, 
boiliiif; at 17^ and another boilinj; at IIS^-IU". The two 
iBoinent are thertfore easily SBparatt'd hy fratrtionatioii. 

Tho compound of tower boiling-point ia decomposed ioto 
alcohol and nitrous acid by the action of cauatic potmh; it must 
therefore be looked upon a» uii ester of nitrous acid, beitlg formed 
vx MOcordaDoc with the following equation: 



NITROCOMPOUNDS. 

TVTion thcHo cstcrt, or alkul nitrites, are reduced, tliey are con- 
Tcrtcd into an Alcohol nnd ammouia. 

Th« comiioninl boiling nt ttic higher t('mp«T«liir(>>bchavee quite 
differently. It in not convcrtert into » nitriw nnd alcohol by tho 
actiou of alkalU, arij on rerloction itfi two oxyppti atonm aro 
replacoil by two hydrogen atonu, with the fonnation o£ a primary 
amine: 

The tut reaction sliowa that the nitrogen in this clasB of com- 
pouitilft is directly liiilivil io caTbi>ii, because tliiit ia the ca«e witl 
titc amines Tli« oxyg«n atoms cannot bo bnlced othervise thaal 
t« tho mtrogon, becauac the reduction to amino takes place at tho 
onlinary tompiTBinrH; it in not poKsIblo iimlor these oimditionx to 
replace oxygen whiL!li i>! linked directly to carbon, for neither from 
alcoholn nor from ethers i« it posaible to obtain, by reduction at 
low tvoipemturcs. Bulwtaiicca whinh do not. contuiri oxygen. Tbiu 
le«ids to the conclui<ion tliut tiu'sc- xubetuuccs, which arc uUlei 
nUro-etmipOHndf, must have tho conirtitiilion C„H,„^,— NO,. 

Xitrty-eompounds t/n>rf/ort contain a group XO^, lht> nilr^am 
atom of which is directly/ liiil-eil to carionj the ffrotijt — .VO, fm 
eiiUed the nifro-group. 

The namea of thcan compounds ore formod from those of the 
iiaturalcd hydrocarbons by the Addition of \\\<i prefix mtro. The 
compound C'1I,N0, is thus nitromethune; C,HjNO, is witroethaM; 
cl4!. yitropara^Ks is the gciioml name of the members of this 
Itomologons series. They are cokmrtefw li<)uidB of etheroal odour, 
iho lower terms being slightly soluble in water; they distil with- 
oat deconi(>o8ition. 

76. The nitronlerivativeB have a number of characterifltic 
properties. One of these is their poEfi^Hsing one hydrogen atoi 
replaoeulile by alkali-mc-tals, e«|jecially godiuin. Thts sodium 
compound 18 meet eabily obtained by tho action of Eodium elhytate 
or methylntc upon tbu nitro-compouud in alcoholic solution. A 
fine, white, crystaUino procipitatc is thus formed, which in tho case 
of nitroethauo, for exaiiiplu, Imtt the composition C,H^NaNO^ 
The intolubility of tlicsc lodiiiiu compontids in absolute alcohol 
can anmetimee be made use of to separate the nitro>paraffins from 
other substuices. 



90 



ORCMSiC CHEMISTRY. 



This pow^r of exciunging hydrogen for eodinm onl; exists 
Then there ie at least one bjrdrogea «tODi linked to th« carbon atom 
to which the nitro-group is attached, lu the eame tav as from 
nitroethnDe, a metallic compoQud is uldo obluiued from secondary 

nitropropwio, CH,-CH<^q«: bat aitrobotMi*, OH,^C-NO,, 

does not ricld any oorrvsponding motatlic dorivutirp. It VOS 
fonnuri; euppOMsl that the malollic atom in thc^e «odium com- 
poands occupied tho position of a hydrogen atom which vas linkod 
to tho corboQ atom attached to tho NO,-group; thog C,li^NftNO, 

/NO. 
mw BQpposed to baT« the strnctare CU,-C-^II It has booD 

^Na 
fihovD thai this is not tho caa«, as will bo indicated in tho seotioD 
dealing with the pftuil^actdi (SSI). 

When an ulkaliiic snlacion of a nilro-componud U brought into 
contact with biommc, one or more 'of its hydrogen atoms, when 
linked to the mme ciirbon atom as the nitro-group, is leplacod by 
lirumiiie. This reaction is analogouH lo the abuie-mentioned 
siib«tttulion by molals, it being etill possible, for example, to iu* 
troduco ono bromino atom into Cll, ■ CiiBrNO, , but not into 
/Br 

cu.-ofcn.. 
Nno, 

77. Th« behaviour of nitro-flompouods with nltroaj acid Is very 
obarnct eristic, and allordfi a motliod of disliDguishinj; pniuAryi wc- 
ondary, aud lerliarjr tiitro-ttenvstives from oiiu noothor. Tli« reac- 
tion is carried cut by adding sodium iiitrile lo aii alkaline solution of 
the iiitro-eompoiiiid, niid (icidifyitig witVi dilute siiliiliuric acid. lathe 
CSM vt » piimarj nitro-camponnd, an alk^Unitrolic acid is formed : 

cir,.c|H7To|NOH = ch. c^j[^**^ + h.o. 

\N0. BUkrlbtirolle neiil 

The conslitotiou of these ocmpoimdA is indicated by their prodoo- 
tloo from a dibromonitro-eomponnd by llie action of bydroiylamine, 
H,NOU ; 



NOH 



OH,.C| Br, + H. lNOH = CH, C^JJq" 

\xo, 



eHBr. 



The alkylnilrollc ncid» dissolre in alkalis, yielding melallic com- 



NITROCOMPOUNDS, 9> 

ponnds with a blood- red colour, tbls reaction affording a cbaracleristic 
test for them. They crystallize well, but are by no means stable. 
The secondary nitro-compoands yield pseudonitrolt wheo similarly 

treated. They contain tbegroup = C<2qQ : 



Propyl pseudomtrol 

The pseadonitrols are colourless, cryBtatline substances, which 
hare an intense blue colour in the fased state or in solution; this 
characteristic serves as a test for them. 

Lastly, the tertiary nitro-compounds are not acted upon by nitrous 
acid. 

Among the other properties of nitro-compounds may be mentioned 
their decomposition into the acid containing the same namber of 
carbon atoms, and hydrozylamine, when heated with hydrochloric 
acid: 

CH.CH.-NO. + H,0 = CH.-COOH + H.NOH. 
Nltroethuio Aceiic acid H^drozjlamlM 



ALKYL-EADICLES LIHKZD TO OTHER SLEKENTS. 

I. AUCn-BADIOLEfl LUTXED TO ElZmim OP THE HITftOOEK QBOITP. 

78. Ammania unites rvudily with uciilH, with rormnlionof suits. 
PboHphoroMcJ livdrogen a];^ jioscMnucii thin properly, Kllliough 
tho plioftphoQhim saXti. Fll^X. &ro deoomposcd oren by water into 
AD ftcjd and phojiptiorptli^d hydr(iR«'n. 

Th« basic charaott-r has whnlly ilimpponri'd iu tho ciwc of 
arwiiiuretted hydrogt'n aud HJitimoniurelted liydrogpu: bi-iniiitb 
does not yield a lirdridr, mid p(iiue«R««, in f&cC, onlj very iilight 
traces of the chttrndteriHtins of inetiil1oid.<). 

Amniouia cannot bo cosily oxidized, «nd is unacted iijion by 
tbe oxyjrou of the atmonphcro at onihian- tempcrftturos, Ou tho 
other liaiid, tbe hydrideg of phoepIionjB, arsemc, and antimonyi 
are eiuiily uxidi;)iMl. 

All Ihtt ahovL'-iiicntioned properties are dUplayed by tbo com- 
pounds wliich these olonienta form vrith alkyl-iadiclctt. 



FhMpblnes. 

79. Thfi KtninM jieM stronger basM than (immouiA; in th« 
way :ti« phwpltiiirt viclil ftlrorjcer Imsoa than rili, this becoming'' 
mor« mnrkM vliti incrcasa In the DumtMr of alkyl groiifw v\\k\i biire 
re|tlnct>d hydrogrn atoms. Tho Htlta of tho inonoalkyl-plii>«tiliiim, fur 
i>*Ani|>le, nre dt>«>mpogetl by water, wh«reas lho»e of tbe tiialkyl-pIioA- 
pliincs iiiirl irialltjl-ithospliiiicsHre not. "iiwqituUrnnryjifioiiphoHiHm 
bastx, I'R.OII, are as stnHigly ba.^io na the nmnicitiiimi Im^t^s. Wli«n a 
pho^)boiiiuui biisc is beali^d, it dors not, like an Hiiimoiiium Ikini', Hplit 
Dp into an alwlnil (or Callm + ll,0) nnil a Iniilkyi bas^, bnt iuio a 
hydrocarbon C^IItn i ■ ni'd an oxygen compound : 

(CE.).POII =cn. + (C,I!,>,.ro. 

Thb subatanw Is callwl tritthyiphosfihine oxide. In tbfs reu>tian, 
tho great affinity betwrcn pho&phorus and oxygen jilayH an iiiiportnnt 
part, ttiia afflnily boing ako indicated by the eau with wbleh the 
phoAphiuei) undergo oiidation, a chnnge ofr«ct«d cvon by tbo actlnti 
of lh« air. Nitric acid oiidiww PH, tn phoBphoHo aoid, OPcOH).; ia 
ananalogous manner the pboe|)tiinQs take up one oiyg«o atom, and ia 



PHOSPHINES AND ARSINES, 



93 



addtlHin M iDAoy oifgen atoms u then are bydrof^en atonw directly 
linked to pliosphonis : 



'^H:P*rtre.^gH;,P:0; 



H ^ '^"*" HO *^ ■ " 



UanomMhit I p bocphl d Ic 
•(.till 

noil (CllOi = r gives iClI.). ~V:ii. 



Dl met Ii y Ipli iM pbtalto 



TiimvUiyJplKMplilni) oilda 

The voDstilution of these compouQds is proved in various nays : 
torioM&oce, by lite fiwt that ttie monoaifiyl-plto^iiMie acida are di- 
baaic, tbat the diaikyl-jJmspltinie acidt arc inonobutc, and ilint the 
trMikfit-piwtpkifte oxidts hftve »o atid t>rupcrli(». 

T)i« [ilicsphinee are colourless 1i<|UKlE witb h penctraiing, stupefy- 
big odonr. Uelbylpliosphinc, CHiPH,, is a gaa; tnothylpho«phiD« 
hi Tery small (iiixntinns has an odour of bynoinilis. 

Itvtbedi of FomatinD.— Only tirliury [iliuspbiiies and pbospUoaium 
compoutids an; (ormiid by (li« itction of alkyl halldea ii|ion PHt. 
Primary and bOOundnry pbosphinci arc oblaiuod by hcatiog i>hospli>- 
Bium iodide, PHiI, with au alkyl iodide uud zioc ozid«. 



Axtinea. 

•0. Tbc primary aad Bcooadary arsince, UiAsCDi and nA»(CB«>i , 
aiv ubuiuvd by rt^luutJoa of mouoiuetbyianteiiic and dtiii«tbyUr«eiiio 
*eid, (CUiillAsO-0}[ aad (CilOiAsO-OU, by aDialg«m«t«d ttno-dust 
and hydrochloTic iiciil. Both atv iinmiMlialely ozidiwd by ilie air. 
T«itiary aiwnes do n<rt yield b»«ee with water. Tboy are (ormcd by 
tbe action of a zinc-atkyl on A&Oli, and from aodium antenidu and 
U allcyl iodide. 

AaNa, + 8C.IM - A»(C,H,1, + 8NaI. 

ttuatentary artonUun basts, however, have stroogly marlcod bask 
liropertios. Tb«y are fortaod by the addition of alkyl hftlidM to 
tntlary anines, and trealmoiit of th« resulting halido with ailrer 
liydroild*, 

Tbe nuMt atudied ataenio derirativoa cunUiiiiug alkyl-nidicleaaic 
Ibe dicodyl comjjoimth. Tli«y were ioveetigated by Bunsrs, who 
gave tbrni ibis tiatne in cousequonc^! of their oSensivc uacH. Tboy 
Arc TAry poitoBovs. Tb« Damo eaoodyi la Applied to tlio monovaleol 

gioup^jj'>Aa— . Cacottgl oxidt, I(CHi)*Ab).0, ia fomtvd by dis- 

tUUcg arsenic irioiidf! Willi the aoelate of an aLkaii-iuetal. All the 
oUier ncodjl cuiniHjti ndn are obtained from cacodyl ottdc; thus 
auadift Moridr, (CH.i.AiiO!, in prepared by boating Ibe oxide with 
hydrochloric acid. This chloride, auJ avxnitti, CCni)iA»-A9{CB))it ar« 
both ipontaDeouBly ioflauimabla when brought Into contaot vlUi Blr. 



94 



ORCANIC CHEMISTRY. 



StibinM. 

T\\a lertiury xtihinen nnd ibe guaitmery M^onUim Ixjses hnve been 
obtained Troin Anuniony. Thn tint nnrnod Are very roxdilv oxidizAtl, 
taking flro HpaiiiHiiuoualy iti tbc air. Tha stibouiiiic bn»>s are quite 
as buic in th«ir ehimotor as lli« corrosp'tnding N, P, mtd Ax dorifa- 
tlTea. The penumietb^l-dorivatiTc Sb(OH>}i is also knovca. 

BiHUTithlnet. 

Bismtitli does not yield a byilridc, but tertiary bismulfiinea, such 
U (CiHt)iBI, HH) kiiown, Thej' ni-e verv uiisiatile, and explode wben 
bented. They do nut form uddition-produvU nith alkyl halidtB, to 
that tb» " liisiiiiilbuniitru baxes " are not known. 



n. AIIYI-XADICLES LIKXED TO THS XLEMBITTft Ot THE CAXBOR 

QBOVP. . 

81. Tho HomRnlB In encli ^roiip or colniDn of (h(> periodlnnyitcm 
are diridcd iulu tvu Riib>ii:ri>up». in otin of wliicli tbv elcnicnta nrc of 
an eleci ro-|>OBit ivv, baMO-foriiiiii); cliarncicr. mid in Ibe other ol an 
elei^tio-iifgaLivc, ncid -forming cboiaclor ('' laorganic Cbemialry," 
213( Tbo first diviaion of ihe carbon graiip coiitnins Litantum. lir- 
coiiiuni, and iburiuiu, and lb« avooud, varbop, silioon, gbriiiauiim), 
tin. and U-mI. Ic Iiiu ^norally htsm ot>&(trved, not men^ly of ttie 
carbon group, but also of the otbor groupa, tbat vnl]/ elemeitl* 6«/m<v- 
tng fo fitviro-fwyafivt xub-yrottpx are capable of yitldimj atkfft-tvni' 
pvutuiv. FitrltitB roaauti, MknmXEJEFT predicled in H^TOlbal tbe ibcn 
uiiktiowii I'lffiiieiit gprfiiamuRi vould, in accordance with its [HKitiuii 
in tbo periodic Byitcm, yivid alkyl-JcrivativcK; tbia prtidicltoii woa 
oonfinoed by the rrsuarohes uf Winkler, to wbom wc aru iodubted for 
tbe diacovery of this eleineot. Titanium being ati element belon|iD£ 
to the electrn- positive ftub-group. and in many reipecta resembling 
tilieoii, it bna not l>ven found possible to prepare its ulkyl-dcriratlreit. 

The alenienUt xillcnn, iierniaiiiiim, tin, and lead, like cwrbou. tini 
tetrftTnleut. Ntimoroos Att«iiipti havo been mad« to praparo oom- 
ponnds containing cbuns of siliouii atoms roaembliug the carbon 
ohaitiB, Dicy have not boen successful, iio compounds coutatuiuK a 
chain of morn titan three silicon atoms having; lieerj jirepaTnl. As far, 
tbervforc, as is at proueuL koovn, silicon lacks lh« power of liuking 
itaeU logrthcr in chains to Ihe same extent as carbon. On account of 
Ibis defect, a " Cliemistry of Silicon ", analogous to tbe " Chemistry 
of Carbon ", U not possible. 

Tbeetlico-alkyls hare acharacler analogous to that of tbc timilarly 
cvDBtllntvd cnrbon-alkyl cum |ioii rids. For uxuniple. njiooti tHraethjfi, 
Bi(CiII,)i. and eari»a tetratOtj/l. CtdU*)., nre Itnown; both u« Ilqaids, 



LJWWCLCi Ul>iK£0 TO METALS. 

iLiV BOt Staled upon by oiiiutr fumitig ailrte or fuming &ul|)hurie 
"nn'A the ordinarj' tcniper&ljrc, bnc ibay botli yiftid sulialiiuliDti- 
prodacls widi chlorine. SGieoheptant, (C,n»),SiH, hiia a petroleum- 
like odour, in vrbtch It irMiubli-s IriMj/lmeUiaitr, {CiUiktCFI. 

Ori^niir compoiinils nf liii tiKvs beon pn|>Arud by Popb, wbJeli coti- 
rxiDilie Sn-Mlnot liuked to fourdjuimilargroupn and ihercfort.- posscas 
ao atifmm^rk Sn-atom. He hae nitio suoueeded lu spUtllug ibese up 
loto llieir 0[)Uc»ll]r-4ictlrQ i»)in|iun«iitA. 



lU. AIXTL-SADICLES UHKED TO KZTAXt. 

82. When *thyl iudkK- h warnifd wiih zine, a whito cnratalline 
compmiiid, (-',H,i!iii, in funiieil, luid wJiuu this is muio litrongly 
heotwl. Znl, unii ZnfC.H^), n»ult: 

SC,H,Znl = ZntC.H,), + Znl,. 

Zinc-«tliyl can be aeparetDd "by dietlllatioii, which must be per- 
forriic^l ill an tpparatiis rr«o from air, bvoaiiso it barns spou- 
taneoiiely when exjweed in it, as do also iho olhvr ziar-alkyls. 

The ]iietHllo*alkyU are (.-otourle^ lifjuids. henvjor tbitn water. 
Ziiic-meUiyl boils at 4<i°, zinc-etliy] at II8~. mid xiiic-propyl st 
146". 

When ftlkyi iodidt-a react witli sinc-alkyle, mtitratfd hifdro' 
carbonn are formed (29): 



cS;>^^ 



■ CH 



• CH* - ^"'« "*" 2<^H.-<^H»- 




The lialogens react T«rjr «norgetically with ziiic-»]kybi, yielding 
alkyt bHiides. 

Sodittin-ailyl aiul poti\isivm-<iR-yl are formed by tho aetiuQ of 
sudium and potassium rea|>r(;tiTely upon zinc-alkyU These iiii-tuU 
(Ib»ulvo in thu stnc-alkyl, au equivalent quantity of zinc scpanit- 
inj;out. Sodium-alky] and poiiuwittm-alkyl have not been obtained 
in Iho pure 6laU% but only in sohnioii in Jiiiie-alkyl. 

Very remarkable coinpouud»t of magnesium hnvo recently heea 
obtaiaed by Obuisard. When mngne^inni^turnin^s arn Iroiight 
into ctmlact with au ethoreul itolutiou of un nlkyl iodide, one 
molecule of the latter being employed for each atom of metal, a 



96 



ORCANtQ CHEMISTRY. 



ruHCtion occurs, the heat (tvolTod thornby raising (he ether 'ta 
tho boiling- point. When a Hiifliciont quimtity of ether is uwd, 
nil the luugnnKitiin ent«rii into solution, forming » compound 
C,lI^,,'Mg-I. This is combin«<I with one molwiile of ether, 
bccnUM* on disiilliiig off the eclier the reAJiIiie still contains one 
mole^'uto of that eub«tADCO for every molecule of the mctAllic 
compound, Further, in a solrcnt other time other, magtiesium 
alkjl lialide is not (ormod. The ethoreul solotion to obtained ean 
be nwd with great adrantage for the epitheais of s^coudarr and 
lertiar; alcohols, wd for other purposes (97 and 111). 

Mervttrtf-olkyi* aie prapared similarlj m the sitMS Mupounds. 
Tbajr do Dot take fire in the air. and ara dangerously potMiioiia. Sucli 
euapootida as Cin.-Ilg-OHar«Btroug bases. 

Id addiiioB to the componuds loeutioned abort, alkjrl-dcriTaiiTca 
of berj-llium. magneaium, eadmiiiiD, alomiAiiUD, thaUiam, and lead 
bare b*en obtained. 



HITKILES AMD ISOFITBILES. 

83. When pfitAeaiiim etliyl aiilphate is diiitille^] witli (lotassium 
cyauide or anhydroua potasaitim /errocyanide. " yellow prussUte of 
potash,'' K,Fe(('N(j, « liquid ut exwediiigiy implesHUit odour is 
oblnined. By meauii of fmctiotia] dUtillaltoit it ciui he xeparater] 
into two portions, both of wliiuli liave thu (ornmla C^U^N. One 
of lliesR, which ix L-iilW fifti/(mrh^i/!aiiiine. Is only prt-aetit lu Hntal] 
^iianlitiL-.i(; it huUii ul Si'-, utiiI has tlit- eumc diMifrrt-eublB email 
u the ori;{Jnul mixture. Th* olliei*, wLJch constitutes the maiix 
portion, h culled efhi/l ci/anitif ; it hoila at !)7^, and after purifini- 
tinii. hai! nii odour by no mentia disajirpeabln, and muuh lofls, 
]>eai-lnttiii^ than that of the other c-ompuund. 

Thpxe iiininert: b(<huve quito differtnitly when acted upon by 
inorganic acida Kthrli-urliylaniini- ie utliu-kc^d by thom at ordinary 
t«inpenitareB; iti; dittagrucublu odour diftappeun, and thv isubstsnce 
itself, rliich at firrt floated npon t,h* acid in the form of an oily 
layer, goea wholly into itolittion. For>/nc acui, C'M,(>,. can bo 
obtained from thi« solution by distillation; and nn wldition of 
oausiiv pota«h to the reiudue in the distilling- flask and subseqaent 
dirtilhitioii, ftliylaininc, {',lIjNIl,, paHses ovt^r, showing that tho 
nitrogen iu ethylcttrbyluniiiio, UjlIsN, u, directly linked to the 
etliyl-group: 

C,H,N + 211.0 = t'H,0 + C,H NH^ 
BthrtoArbjIaaiin^ Formic' aod Eihyluuliia 



Ethyl c}'anide is only slowly attaclLed by inorganic ooids at 
ordinary temperaturcB. bui more qiiiekly on heating. The reaction 
ii carried unt in a flaek wiih n rotlux-condoDBer. tuid if after its 
compk'tiou the litjiiid is distilled, ^^roptortic acid. C^H^O,, psRsen 
Dvor. This acid contains the same niuiiher of carbon atomei hm the 
original fompound CJI^X. On making the reaidno in the flask 
a)kalin<'. and dietilliug again, a volatile btwe, aritTiujnia, ie found in 
the diitillftic. The nitrogen in ethyl t-yanide cannot therefore, ho 
direetly linked to the ethyl-radicle: 

O.H.N -f aU.O = C.H.O, -f- NHr 



,8 



ORCAfilC CHEMISTRY. 



I 



It inu^t be coucladed from tbee? fucte that the uitrogeD of tb« 
oompoiiiid with the lower boiling-point is directly liukeJ to the 
olhyl-groui»t, autl the three carbou atom^ itru uot directiv liuked 
to each other, in \now of the e»ae with wliich one of the carbon 
atoms cnn be split off as formic acid; on the other hand, there 
tniiRt bo a chain of three carbon iitom» prejient in the cnmpoiind 
of the higher boiling-jioint, sinre siich ii chiiin is founil in i)r5- 
pioiiic acid (87). and the nitrogen ut not directly linked to the 
ethyl-group. Tiieac propertioa are expretwed by the following coii- 
stitutionid fontmln;: 



I. 0^,— NC. 

Oarb/l&iRiDa 



n. C.H.— ON. 



On luM^niint of their method of formation, each must contain the 

group CN. 

Compounds having a etniotural formula like I are called carbijl- 

amines or iaciiitTiicit; thoec having a titnictumi formula like II are 

called r_Vrt"i'dw or mfrtlte. The former are called after the alkvl- 

nidiclo whic-h they contain, thus: mfth>flrtifhy}am\nt, efJitflear- 

btflannue, ©tc. The latter are called in »u sualogoim nmoneT 

methffi cyniiidF, etfij/l lyttNt'de, etc. although the word uitrile is 

more fri'tjimutly used, wliuu tht-y an- nunicd after the acid from 

whifli tht-y may be rcgurdwl lui dcriv*J. Thus, CH,-OX ieacefth 

Hitritt, and V,H^-ilii prQ/noHiirile, etc. 

The conatitiitlon of the groups — CX and — N*C requires further 

111 *■ 

consideration. They are represented ah — C z N and — N =C,' 

there bfing in one case a trijdo bond, and in the other a quadruple 
bond, between C and N. The reason fur adopting these fonnulw 
in preforonee to »uch a one, for example, aa — C^N=, in which 

II 
free linkings are present, will appear later (128). 

Tli« exisleiiM of n dlvalvni carbon atom in Iho c;irbylamln«s. thai 
m n 
b to uy, a group — N = C, ij assumed by Nrp aud some othtr 

cheinUts. 



Carbylamines. 

84. These eompoiuidn are the printnpal product of the reaction 
of alkvl iodides with silver cyanide. They can also bo formed by 



CARBYL^MWES JND MTKILES. 

of caustic potash »nd chloroform, CllCl,, upon primory 
aminae^ whea they are obtained free from aitrilc-e: 



NC. 



C^Njnj + Cl HCl,! + 3K0H = 3KC] -f 3R,0 + C.H, - 

On am>[iiit of thu extraordinary Hiid chAracteristic odonr of 
the carbylnmitKis, this reaction affnnls an exeMtlinfflif deluaie test 
/or primary miiineg, eJnce aecoiHlary ami tertiary amiuue vouM uot 
yidd carbvl amines hy the reartion reprosentcd in the above equa- 
tion, for this reqiiiree two hydrogen atoms to b*" diroctly linked to 
tbo nitrogen of thu amine. 

The cjirbvlamines are colourless liquids, very stable towards 
alkalis, but readily coiiverlwd by acids into & primary amine 
aitd formic acid. They yield unstable addition-prod ii eta, such as 
SCJ3,NC-:)HC1. by the action of dry HCl in ether«4il solution, and 
may therefore be looked upon as posseaaia^ veak baaic properties. 



NitrilM. 

8A. Tbeee constitnte the chief prt^duct obtained vrh^n potasBinm 
cyanide reacts with alkyl iodides, or when it i^ submitted to dry 
distil1ati<m along vilh an allcyl poLattsium sulphate. It in »uuietjmes 
an advantage to nte auliydrous potassium ferrocyanide, K,F©(CN),, 
in8t«ad of poUsAitim cyanide. 

la addllloii tu hcing obtainable by metliods to be dc-^cTihtid in 110. 3. 
DJtrilM may be prepared by tbe action of an alkaline bromine solution 
(German, Bromlaugf) on primary amities, in accordauce with the 
[«1l4wioK eqoAtiona: 

O.H,.CU,.NH, + 2Br, + SNaOH=C,HuCH,-NBr. + SNaBr + au,0. 
Cin»C{H,{NiB^i -+■ SNaOH = CH^CN + SNuBr + 8H,0. 

This teactJon In only spplicnble with advantage to tbo higher primary 
amines. 

The Ditrilea are UqiiidK of characteristic odour, and have apecilio 
gnvitiee about 0-8. They are aoluble in water. They are con- 
verted not only by acide, but aleo by warming with sillcaliB. into 
Ammonia, and fatly aeids rnntainiiij; the mime number of earbon 
atoms. This proceii is called saponification of uitrilee. They 



100 ORGANIC CHEMISTRY. 

have the power of fonning addition-pruducts with many sabetanoes, 
the triple bond between nitrogen and carbon being thereby broken 
and converted into a single bond. An example of this class of 
reactions is the addition of hydrogen: 

C,H,.CN + 4H = C,H,.OH,.NH^ 

T^ts results in the formation of a primary amine vtiih the same 
number of carbon atoms. The reaction gives a particularly good 
yield for the higher members, when sodium is brought into con- 
tact with a mixture of the nitrile and absolute alcohol heated 
to boiling. 

A description of a number of other addition-products of the 
nitriles will be found in 106. 



ST. TC. ■WI^Tf~-S». 



ACIDS. C,.H,,.0. 

86. It wfta stated in 82 that n solution of Bodium-alkyl in rine- 
allcj] is obtainHil when tUHlinni roiictn witli the lattor. \V)ipn a 
ttream of drk' trurbon dioxiJe in jiiuMied iiitn tliis anliitinn, tlmrn is 
formed thv sodiura salt iif uti lu^id wlilch contumit one ctirlion atom 
iu tlic nioluculc mon! tlmn Ibu iil kyl -group. Thus, aodium-raothyl, 
CHjNii, yields Bodinm ncotnto, C',li,0,Na. This roflolion uiAV be 
cxplftincd by nwmning that tho sniinm atom is roleiwti from tlin 
alkyl-gronp, mid reacts with CO,, bflconiinR linkort to ono of ita 
oxygen atoms, for which it poHttBMea grmt jiffinity. In this way 

C^.. is ctinvertwd into — f <,.». Siuc*? thin gmiip. and also tlio 

alkj'l-radicle from which tlio sodium atom bus been Hepamted, hare 
ono tree carb&u bond apien^e. it may be iiamimed that the two 
groups unite, formlitg a roiapoitiul 



In accordance with thia peaetion the acids C„Hj„0, contain the 
gronp — *^'<ftii li'ikod to an alkyl-radiclc. Thia Tiow jg supported 

b}* the lonniition of thece componnda hy other methodft. 

Among HUi^h rea^^lions may be mentioned, Gn>t. the Kynthf!aia 
of the acidH from the interaction of an ttlkyi iodide and ]iot!ifiRium 
cyanide, and Hapoiiification of the resulting nitrite. This HHponifi- 
cation coRsiete in the adding on of water, and fntailH brt-'akiiij; the 
bonds between atrhou and nitrogi'n in tho group — C h N. If tho 
bond in a nitrilo ('H,-CH,-Ct[^ . . -CN were broken at any 
other point, it wonlH involve a breaking of tho carbon rhain, 
and prevent the fnrmatinn of an acid containing the fame number 
of rarbon atomH ait the nitril4>. Tlici saponili cation of the nitrile; 
in which an acid and imimonia are formed, may tborefori; be le- 
ganied ae taking place in tlie following loauucr. The mulcctilcs 
of water split up into U and OH, the hydroxyl uniting with the 
carbon, and the hydrogen with the nitrogon. If thiK happens 
thrw timPB, the nitrogen is converted into ammonia, the three 

bonds between carbon and nitrogen, in the nitrilc, being broken: 

■oi 




OKCANIC CHFMtSTRY. 

cn.-c^on H^N. 

The fonnnlA of tbe ncid formed is not rn,>CO,H,, bqt 
Cn,-CO,H, containing mio rngleciile of water leiw. When one 
moleoilc of vHtor is split oS from CU,-CO,n,, there rceulta 

oin 

Cir,-ClOlI — *CiI,-C5<:ym n enbrtance containing tho (orbitzyl- 

OH 
group. 

In thin explanation uf the formation, of auids, th« oxistcnoo of 
iin int(*riiieiluitt> compouud c-uutniiilug Uiruy hyJroxyl-/n>ups U 
iistnimed. Such Huhfttuntro^ »re not kiiovru, hut thti HSHumpdon 
Booms hy no mcaus improbable, becantio componndK oxint con- 

taining three alkoxyl-groupa: for example, C1I,-C. OC H.. 

Subetances of thi« kind iire called orlJio-estirrs (159). 

The AcidN (?„H,aO^ can »\so be formed hj the action of carbon 
tnonoxiilo on mutallic uIkoxi(le« nndcr thti iiifluonoo of heat: 



CU,-OIfa+ CO = Cir^COONii. 

The formation of an ndditioiwproiluot hetweeit Cllj-OXa a.ud CO 
can he explained oy the aH.'tnmption thnt the alcoholate first 
deoompoaeo into CD, und O'Sa. 

It was mentioned in 49 and 60 that primary &]oohoU arc con- 
vertt-d by oxidation into aoids with tho general formuhi t'„U^O,, 
coil tuin ill j{ tho wime number of ('•atoms in th« molccnlo. In 
thiii rpnotion tho group — t'll,OH ie oxidized to — COOH. 



Thv higlivT primnry nleohols can nleo )>□ converted Into the corre. 
sponiliD)!; iickis by liRHliog Itjvni wiib sniU-liiu«. fr>M liirdrugvn bpiug 
formed m * by-product : 



CHHi.ClI.On + y»OH = C„II.. WONa + SI!,. 



tA proof of tho preeonce of hydroxyl in the carhoxyl-group is 
BfTorded by tho action of the ohlorideKof phn«phoni«, whioh effect 
tbe rupWemeiit of the Oll-groap by 01 in thi> name vay ns with 
the olcoholn. 



FATTY ACIDS. 



'O^ 



by metals. Sinc« the lijrdrogcn atnm in the rarlwxyl-groap 
occupies a spocinl pmition, being the only one diri-t;Uy liukcd to 
oxygen, it is nntunil to euppoao tliat it ib thiit hydrogen iitom 
which ia rcplnroftbln. This is pa-eily provcri by troniing silver 
a<>etute, f',H,OjAg, with otiirl iodide. Ethyl aontat* is lormetl, 
Hm) not butyric afid, ax woiih! be the case if the Ag-atom were 
prf«cnt in the methyl-gronji; tlins, CH,Ag.COOFr. 

87. The lower members of thia Beries of acida are liquid at 
ordinarr tomporaturcs. They can be distilled without decomposi- 
tion, and, vhcn piir«, have a Tory irritating and stT<>ngiy noid 
odour. They are misciblc in all proporLioug with wntpr. The 
middle members (C,— <.',) liave a disagreeable ninciJ smell. They 
are of an oily natnre, and do not niii with w«t«r in all proportiona. 
The higher members, beginning at 0„, are solid at ordinary tom- 




Fio. 8fl.— Mei-TiHo-roiirr Oobtk or the Pxttt Anns 

peratiircs. are without odour, and resemble paraflln in rharacter. 
They arc almoet insoluble in water, and eannot be distilled hi the 
BtmoBphcric pressure without dt<i?«>iii]io8ttion. All the nridii of this 
eerios dissolve roadily in uleoliol and ether. With the exception of 
the 6r«t member, they are very stable townnU oxidisiug-agenlii. 

The Hcida of the aorius 0„H,„0, are called the fatty neidtc, on 
accoont of the fact that the higher members vtvtc fir«t obtained 
from fata. 

Many of the tntty acids oc-eur in nature, either in the free Htat«f 



I04 



ORGANIC CHEMISTRY. 



or M esters Tbcy are of gnwt tbeoretical «nd technical impor- 
tance. Tho following tublu containe tho Danif>e, foniiiilw, anil 
certain phf^ical couslauta oi the uonoaJ'cliaiu acida belonging to 



the Herios GJ\^0^: 










Kudo. 


PariBula. 


HdtlnK-polat. 


BnlKBc-iMlnl. 


BpaHfleOmviV. 




r.H,«, 

<-.H,.0. 

C,H,.0. 
C.Bi.O. 
(.11,. 0, 

c,.u.,o. 

C,.H.,0, 


14-S88- 
-83* 

- !.«• 

- M-.V 

- i-r 

- 10-5* 

16. a* 
n-y 

81 v 

fla-eiB* 

60* 
69 -Sa* 


101' 

lie* 

141' 

162* 

188* 

»5* 

323* 

88T.5* 

3U* 

9fl»' 


l-*81fl(10*> 

i-osuiir) 

0.W8B(I4*) 

0-9M0 0') 
0-9450 0*) 
0-818e(l7.2'> 
O-filOOfJCI'l 
(i»110(>i P) 








Hkrgtric Acid 







Althougli the Iwiling-point riBee regularly for every innreiuie in 
the number of C-Htoraa in tho molecule, ihe mt-Iliug-poiuta of th« 
acids containing an eycn number of C-»tomH ara higher than those 
of tlie acids immediately pruo«ding imd auccoeding thcra. with an 
odd number of C-atoms. Thia ia dUtiuutly seun from tho cur^'v 
Bhowd in Fig. 29. This phenomenon has aUo been obftorvod in 
Kumo (jlhor humologoua s^riraj. 

It is often necetiKtry to oonsidrr tho gronp whifh rcmfiimi when 
the hydroxj'l-group is Kupposod to he removed from a fattr acifl. 
This group is not known in the fnw etuto. It in named aft«r thf 
corresponding acid by changing tho torminution " ic " into *'yl"; 
thns, 

HCO Fomyl, 
CH, . CO Acetyl, 
C.H^CO Propionyl, 
C,lI,COButyTyl. 
C.U,-C'0 Valcryl, 
etc. 



Pormlc Acid. K ■ OOOH. 

86. Tliie compound derivt-s its name from the fact that it 
occurs in the hodieo of ants {hatxa, forimai). It oan be obtained 



FORMIC /tao. 



105 



liy pastting carbou monoxide over aodH-linir at 210'^, t1ie vteld being 
gDoil (86). IL U, liowefcr, usually prepared by ani>tLtcr method 
(168). It lUfty aleo b« obt&iiic4 by the oxidation of methyl alcoboL 
A pecTilinr method for ita formation ia to submit carbon monoxide 
and 6t«am, or carbon dioxidu and hydrogen, to a silent oU'Ctric 
discharge. 

Pnre formic acid U a coloarlesH HquM with an imiating orloiir. 
It$ salts are caiWeA formatett and uru soluLIu in water, Homu of thum 
only with difficulty. 

Formic acid i^ dietinpuiehod from its homologiieBt first, by 
ibe ease with which it nndvrgooij oxidution, it being therefore a 
good rvducing agent; second, in being oa«i1y decomposed into CO 
and HjO. Wien mercuric oxide is added to a Roliition of formic 
acid, a solution of nierctiric formatv in obtained. If this hf filtered 
and varmed. mercurous formate ie precipitated with 0%'olution of 
CO,) aud on further vanning, metallic mercury io obtained: 

Uwnmc romuto »ffrm«u 

H glOOCH + H|COO |Hg = 2IIg + CO, + HCOOH. 

In this procem half tlio formic acid in the gait is set freo, and half 
JB oxidized. An exactly analogous reaction takes place wlien a 
Bolntion of Bilrer formate ia warmed ; metallic silver is precipitated, 
carbon dioxide evolved, and half of the acid set free. 

When formic acid it: warmed with concentrated sulphuric acidi 
water and carbon monoxide are formed : 

IMlC0jOHis=U,O + 0O. 

The Muno effect is produced by the introdtietion of finely powdered 
metalliu rhodium into an atineons Mintion of the acid, whi>ii tlie 
rlecomiKMition tHlcm jilace even at ordinary t«m])aratureK. The 
rhodium actu iia an nccolerating, catalytic agcTib. Since reactions 
whirh of thcmaelves would not take place cannot be brought 
abont by catalysis ("Inorganic Chenustry," 2G), it foUova tjiat 
formic acid decomposes of it*olf iu the above sense, althonpli wi 
slowly na to seem perftn'tly stable. This applies to a large number 
of organic compounds (/AtV/., 104). 



lo6 



ORGANIC CHBMtSTRY. 



It vill liJive been noticed thnt the general properties of formic 
BCiii OillcT ill Bomt! ruBpefU (rum those of the other acidy of tiie 
homulo^oim mrivi iu which it is the loweNt membpr. As will be 
Boun later, this plienomenon is of frequent oocuirunca-^ 



Acetic Acid. Cn.-COOH. 

89. This substunci) hiui b«cn kn(>wii lonyor than any other 
acid. It i% outnafactiired by two ditlvrvQl nintho<i«. 

a. By allowing Uilnte aleohol, wine, boor, otc, to bcoomo 
oxidizptl by <'tpoHure to the air, with pmiln«tion of vinegar. The 
oxygen of the atmosphere a<:tH upon the nlrohol with the aiil of 
bacteria, aiid the pn)ccjw mnat be 50 regulated that thette bacteria 
prodncc tli« groatvft possible fffuct. To this end it is important 
that tho tompcratun- should be kept aWiit 35". 

In the "qiiif^k procMs" for th* preparation of vinegar (Fig. 
80), dilnto aldohol (il-lO*) ia nllow^ to drop on beoch-wood 

gbaTirigs contttiuod in a vat with a 

perforated false bottom, a. Holes 

are bored in tlie eidea of the vat near 

the bottom, serving to admit an 

ascending etreain of air, opposite in 

iIire»:tion to that of the alcohol. The 

Bhavinga of buecli-wood have the 

effect of distributing the liquid orer 

a vt-nr' Inrgtf Biirfai:^, iind so faoilitttt- 

iiig the oxidizing a<;lioii of tbo air, 

Mm JRSSnHR. <*'bil« at the «ame time tbey e«r>'c M 

BI^B '-V *j l' - ■ ■ " — f— ' a feeding- ground for the bacteria. 

fJB WM . . ' . '" I . .. . — i::^L_^ b. It has been mentioned (46) 

I wKH that acetic acid ih obtained in tbe 

dixtillatinn of wood. Ht treatment 
with qiiirklimt;, tlio ai-id is converted 
into calcium aoetatoi which is freed 
from tarry imporitiee by heating it to SOti" in the air. Tho acetic 
»ci<l iu then set free by distilling with an cquivaloiit quantity of 
cont-'entrated liydroohloric acid. It can be puriSod by diBtillation 
over potatwiuni bioliromale, being very stable towards oxidizing- 
agcntM. 




Fro. 30— I'llEl'ARATlOM i>l' 
VjKSOAK ur TUK "QUICK 
pKOtKHB." 



MCETIC ACID. 



1*7 



Anhydrous ftcctiftBcid isBolidattompemturcBlwloiTlC -fi'fWheii 
it haa nnurh llie upiienniiico of io* : Ii«ncc tli» namn glacial acfU^aetiL 
ll has a Teiy |wnutrtttiDg odoar, and is obtained by lUlowing a very 
cottcentmtoil Halation of acetic acid tn solid ify, poiiringolT theliqaid 
reaidne, melting ttip sniidifipd arid, again allowing it to crystal- 
lize, etc., these operations being repented until the meUiiig-point 
ia constant. A rUe of tempen»t«re and contraction ol rolume OBOur 
when glacial acetic a<!id ia inixud with water, the maximum rise 
aud oontractioii being obtained by mixing in tbo ppoporlion of ouu 
gnimme<mi>l«cul»of acetic acid to ooegramine-nioluciileof wutur. 
This fact IB I'vidt-ncL- of Ibo i-xisti-iiL-o of n L-onipouiid called oriho- 
offl/iCfifr<;(B6),withtUcrorinnIa<.'lI,C00H.U,0=CH,C(0U),. 

A 55 per cent, eolutiou cf glacial acetic acid in water lias the 
same specifio gravity a« tlio pure, anhydrous acid. Wlien water 
is added to glafinl ai-etif? iicid. the spwifio gravity of the mixture 
flrrt riiiee; further addition of water cuuHus it to fall. Thin cir- 
cnnutanco mnkcM it impuHsibk- to dcli-nninc the nnionnt of aeiJ 
present in Buch misturea by tlio diinplu iiwj of tliu hydrometer. 

The strength of very concoDlratcd acetic acid ia bc« det'crmioed 
br an ot>s«rrBtt'>n of its melliiig-pmut. n tbttrmonit'l^r grii(lufic«l 
In tenths of a degree being uaod. In accoroaaco with iho farmtila 
giT«o in It, 

1li« presence of IS of w»ter (itictl('C:iilar weight 18) wotild, »Inc« tho 
coiitlniii for glacifti acetic acid is 39, uauao a lunuriiig of the frvoxing- 

UQ 

point M) of T—, or 2-16°. Siiiuc a thermometer f^raduittiMl in tenths 

Irs 

can oflaily tx- rend to wttbln ono-t went loth of a ili;gr«e, the amoTint of 

I 



water oaii be determined to wilbiii 



or Q.ozfa. This is a 



Sid X 20' 
dugree of acciirncy tnialtainnblu by IkratJon. 

When either no very grout ncciirncy U rcqutrod, or the nretie «cid 
is dilute, il is best to dctormiiie the strength by titraiiiiK a weighed 
(laaDtiiy of the aolution with a Btnndard eoliilion of nlkah. 

The rupour density of acetic acid at temperatures sligblly 
above its hoiling-pnint Ik twice ua great as that correaponding to 
tho formula C,il,<),. At about 200", however, tins vapour denaitr 
ia uormnl. A similar phenomenon has been obgen'ed in the caae 
of many otiier fatty acids. 

Tbo accialts, or saXis of acetic acid, are gcncnUlj iwlublu tn 



io8 



ORGANIC CHEMISTRY. 



water, tb« silver salt dissulving with dif1i(>iilty. Wlien ferric 
chloride vt addvd to the jialution of &n ttcetste, such us sodium 
acL-tiitc, ii blood-red colour is pruductid, owing to the fornmtiou i>f 
ferrio acctaUi (the isalU of fomiic: and prupjontc acidit produce the 
samo reeult). When this aolation U sutHciently dilnt«, a brown- 
red precipitate of basic ferrio ncoLate, ^c .ktl.*, is produced od 

boiling, acetic acid beiztg liberated at the same time. 

A vt'T)* delicate test for acetic acid is the formation of cocodyl 
oxide (80). Owing to the extremely poieouaue nature of this 
BiibstAnce. great crare must be exercised in applying this test. 
Among the acetates of techuical im^jortance arc had acttate 
(" augnr of lead "), dasic lead aceiatr, and aluminiwm acetalt. The 
first two are used in tbu luauufacturt; of white lead, aud the third 
as a mordant in caUco-priatiiig (381). 



Butyric Aoid«, n,n,0,. 

90. Two ieomcrin acide with the formula t^U^O^'aro known. 
Thoyaro normal butyric acid, CU,-CH,'l.'ll,-C0OH, and isobutt/- 

rte acid, nir'>CH-CO0n. The constitution of these acida is 

proved, by their sTiitheais, the normal compound being obtained 
from fj-jirfipyl ifdidc, mid iho ido-acid from isopropyl iodide: 

0H,.CU,CIl,l-^CU.OH,-0H,CN-»CU,-t;iI..Cil,COOH. 

CH. 



^^•>(;hi— [;^>cu.cN. 



'CH 



»>cii.coou. 



The normal compound ia nlao called femimtaiion htityrie acid, 
from the fact that it can be obtaiiitid by the fermentation under 
certain conditiouo of mc\\ substances im sugar. Jt baa an extremely 
disagreeable odour, and can only be oxidised with difficulty. 

Butter uontoiiM aboin -l-rij of /i.butyric aci<l. along wilh smaller 
qnnaltUes of older volatile iK^iils of the fatty serie*, imi?ili aji eaproTe 
aold. Tlieee ara probably [in^di^iil iu itiu form of i»ton. Since *' volt' 
tile fatty acids" are not ahiaimil by fiflponilicatinn of other fata, 
wheitier animal or vegetable, llitir prfseiico fiimiahes the moat char- 
aoWrisliedlstiiielioii Iietween butter niKl mnr^Krine. wliiLhisamiiiare 
of animal aud Tcgi'lnblo fats. Knee the ])ercenin^ of vulatite fatty 



I 



r 



MrCHER FATTY AaOS. top 

\ acids m butler ia uul a voasUiit quanlitj', but may vary between vride 
liiuils. It is Imposslblfl in oBrtsii] cases to idenlify a mixture of batt«r 
andraargarin«b7adet«riiiinatiflnof llin amountof the»« acidApreaenC. 
By the applicalinn of other IgsIs, it is Hometimoii pontble to obuun 
Rliabla results iu doubtful canes. 

Isobutyn'c acid aluo ha>i a TerydiRiigrc'T'jibli? itmi?]l. It h a com- 
pound contiiining a tRrtmry hydrogcm atom, and experience liaa 
shown that such compountlii arc very caalj oxidized, so that 
oxidation atTords a method of dietinguiahiiig between tlie nornml 
ndd and tho iso-acid. 

Th« culciam salts of thoM acids also oxbibit a nmikrlfflblo 
difference in properties, thnt of the normal acid being lo'8« soluble 
in hot water thnn in cold, while that of tho iito-acid follows the 
ordinaiy mle, and is more goliihle in hot than in cold wnter. A 
solution of normal calcium hiitvratc saturated at 0° deposits con< 
eidenible quantities of tho salt when heated to about 80^ 

In accordance with tho principle of mobile eputidriutn ("In- 
organic ChemiHtrj-," 288), normal calcium butymtp should disaoWe 
in water with sliglit evolutiou of boat, tind tho cnlciiim salt of 
isobntjTic acid with slight abeorjition of heat. This view is fully 
supported by the rcsalta of experimeat. 

Eighsr Fatty Acids, CdH,„0^ 

91, Uany of these occur in nature, chief among them being 
paJmitic acid, C„II„0,, and gttaric add, C„H^O,, both of which 
oont4iin normal carbon ohairui, as will he Hhown later (144). They 
are fonnd in very large quantities lui esters of glycerol (1&9), 
being the principal conntituent of most animal and vegetable fats. 
They are obtained from these by Baponification, a process carried 
out by heating either with slaked lime (101), or with concentrated 
sulphuric acid. Sulphuric acid causes slight carbonization, with 
tho n^iill that tho ftitly tmds Imvo a d&rk colour im])itn<id to them. 
Thoy coo be purified by dietiliation with superbeated tuenm. By 
sapODtfloition of fats in this way, a mixtnro of fatty acids is 
obtained, which is semi-solid at ordinary lemperaturoB. It eon- 
tains the two acids mentioned above, which, when pure, melt at 
62" and 69° respectively; when mixed, each lowers the melting- 
point of the other (14), Moreover, the liquid oleic acid, whtoh 




I to 



ORGANIC CHEMfSTRY. 



belongs to auotLer homologouti Kcrivs, \t &I0O pni«cut; it au be 
pressed oat of the mixture, Icaviag a vhitu, solid aubstouco used 
in the inaiiiifiinturo of " stenrine" cnndles. For this purpose it la 
molted, and a little pumlUTi wax added to prorent tlio crj^lalliza- 
tiou of the fatty acidB, whiith woald make the caudles very brittU: 
the molten miiRs iR then pounMi into moulds, in the middle of 
which wicks are fastened. 

Houfs are the alkali-ttalts of the fatty acids. The; are prepared 
by siipoiiifying the fata with solutions of caustic soda or cauBtic 
potniih heated to the boiling ti-mpfrnturc'. The potassium -soup 
is oalled "soft «oap," uud UHiiiilly had u yellow oolour. In nnme 
countries the colour in changed to grcou by the addition of a little 
indigo, the aoap heing then known aa "grueii aoap." I'otaeaitim- 
HOup roDtainii not only the potaseiiim salt of tin; fulty aeid. but ul«o 
the g]yccrt>l produL'cd in the reaction, and a considerablu propor- 
tion of wat«r. Sotlitim-flonp is hanl; it is Aeparstei from the 
reaction -mi stiire, after saponilicatitm is pomplele, by " salting-out," 
which conRiKtii in the addition of <_'ommoii ndt in the solid state to 
the mixture at tho boiling tvmprrnturc. Htnce the sodium i<nlt of 
the fatty acid is insoluble in » cuni^outruted solution of eodium 
chloride, it sepaiittcs out in tho molten EtAtc, forming n layer on 
the Biirfttfle of the brine. The glycerol remains dissolved in the 
hittvr; tho sonp obtninod in this way ennsistA of tho sodium salt 
of the fatty acid, together with a small percentage of wat«r. 

9^ The cleAHsing action of soap msy be explained in the fol- 
lowing way. As early aa the beginning of the nineteenth centurr 
it was pointed out by Cheveeul that when au alkali-aalt of one of 
the higher fatty acids is bronght into contact with a large «x( 
of watci*, it de'^ompuses with foTmatioii of free alkali. The Mid] 
thus libonited unites with u second molecule of the salt, fomiin^l 
an insoluble substance, which with the water produoes the lather. 
The presence of free alkali in dilute soiip-soltitioiis can be readily 
shown a» follows. A coni^vntnittid soap-solution is only verj 
slightly coloured by phenolphthalu'fn; but the addition of a largtti 
quttDtity of water causes the development of the red colour, du4 
to tho action of the base thus liberated on the phenol phtbalem. 
Tlio MiJip has tht'reforc undergone hydrolytic dinsociHtion ("In- 
organic Cbemtftry," 239), owing to the weak acid propertios of 
the higher fatty adds. 



ACTIO!-/ OF SOAP. 



Ill 



Thft suiliuK of ttic akiu, clothing, etc., is nsiially ilue to suh- 
etiiiK-ia ol tt fiilty iiaturu. Wleu a fat ia brought into contact 
vith an ulkatiue liquid, and tko mlxtare abakcn, » part is 
saponified, and dissiolvea. Thfi ffrentcr portion, howftver, roinaina 
8nBpen(lc><l in the li(|Uiil in the form of iiiinnte dropK, which givv 
it a milky Rppeamnrp. Tht* product in cal\m\ an pmulsiou. The 
alknli lihenited from th» soap has therefore both a Kaponifying and 
an eniiilfiifying action on tito mibtttanru to which the noiiing ie due. 

If tho corrcctuoi^s of this (.-xplunution in admittod, ttiu (|Uciition 
arises as to wliy (roe alkali eh<>i!ld not bo Uicd inati'Jid of soap for 
wu^biiig-piirposeii. It ia fwi'iuitto tho use of eoap provonte thp pros- 
cues of an oxcessiii'o proportion of free alkali. Tho proportion of 
alkali libenttcd from «oap ia small uHth a iiinall quantity of wat«i', and 
large with » large qnivntity. nut the addition of a large quantity 
of water doea not very much affect tho concentration — the amount 
of free alkali in unit volnme of liquid — since, although it prodocea 
mtirh froti alkali, it ^tmullaueously dihitua tt. Tho use of soap 
ha« therefore tho effect of automatically regulating the amount of 
ttve alkali prcSfut in thf watL-r, and ki>i^ping the solution very 
diluto. Tliis would not be the case if free iilkuli W4.'re employed 
iu^teftd of soap, and the hitter poKseascs the fiirthtT advauUigci uf 
formiog a Lather, whicli takes up tho dirt and facilitates its 
removal. 

When water contains a certain percentage of calcium salts, it 
i« said to be hard ("Inorganin Clieniigtry," 269). Sueh water 
docs not lather with soup, but raiises the formation of a white, 
floccnlcnt eubfltiuioo. iK)nKifitiiig of insoluble calcium paltg of the 
fatty acidK. Hard wuti>r is thcrcfuru uiisuitablo for wai;hing 
boeauee it proventK ilie formation of a lather, and aUo because 
the alkali combinej with the acid of the calcium salts (miiphate 
and oarbonate) prc«ent. 



Electrolytic Dissooiation. 

93. It 18 fully explained in " Inorganic Chemistry.'' 65 and 68, 
vhy motecnlea of acids, bases, and ealt« are a&sumed to split up in 
Hi^ueoiici Aolniion into partick-s called ions, (charged with oppooiie 
kinds of electricity. In such a solution, an acid is cither wholly 
or (>irlly split np into positively charged hydrogen ions, H 



Ill 



ORGANIC CHEMISTRY. 



(cuttoii^), and negatively charged anions: for acetic acid, H (po«i* 
life), and (C,H,0,)' {negatire). Bases yield a positively cbargedj 
iQucalUc ion, and a negatively charged OU'-ion; aalte a posi- 
tively charged metaUic ion, and a negatively charged aoid-ndicle 
ion. 

tt is further Btat«d {IhuL, M) chat in the solution of a jurtlj 
ionized huWuiucu un equilibrium uxista which can be exprefticd in 
the case uf a mauoli»sic acid by 

ZU^Z' + H, 

where Z' represents the acid radicle. If v ie the volume in litres 
containing one gniniino-moleculo of the acid, and a is the portion 

ionized, then the concentration of the ions it -, and that of the 



□n-ioniscil portion is 



1 - a 



The eqnation representing the state 



of eqiiilihrinm in the case of the above example of a monobasic 
acid is th^ireCore {IbUI., 4S) 



In this equation it is oonstaut, and \i called the ioHitalion cotitloHf. 
It has been ahown that this equation affords an exact measnre of 
the amount of ionization in the case of the very weak orgamc 
acids; tliat is, expresses acoumtely the connection betweeu the 
dilution tt and the ioiiijsation a. For this reason it is Cfdled the 
Uiip 0/ dilution. It was discovered by Ostwald, who dissolved 
one gramme-molecule of an acid in different quantities of water, v, 
and n^certaine<l the ioniiuitions a by a determination of the cleotnc 
condiictiTity. On eiibstitiiling the vahict* ohlained for tt and v 

respectively in the c^ipression — :. the luttur wus always found 

to have the same va]ae, as it mual if h h cousiant. 

As the constant is a very small nnmber, it is usual to multiply 
it by 100, iiTul to denote tliirt qiimility by A', so that A*= KhU^. 

The Hccuracy of this law will be seen from the examplve in th« 
following table: 



IONIZATION CONSTANTS OF THE FATTY ACIDS. 



««3 



AMUe AMA. 


Fropienw AcU. 


n.Buijiio AiHd. 


w 


lOO* 


lOOb 


V 

9 


]<»a 


lODt 


V 


lOOa 


lOOb 


8 


t-tw 


0-00190 


i-oin 


o-ooiao 


8 


]-(H8 


0-00144 


IS 


1-678 


0-00179 


10 


MM 


000194 


te 


i.ri;i6 


l>>(M>iau 


8S 


3'8W 


0-0ai8'3 


83 


a.Offlt 


0-00134 


3£ 


2-l«-'V 


U-OOliO 


«t 


8-38 


0-001711 


0-1 


2-t40r> 


OOlSS 


U 


S-OAS 


0-001» 


IStt 


4-68 


0-0017» 


12tt 


4-Oi 


O-OOISS 


198 


4- £09 


0-OOlM 


lOU 


tS-H 


0-00177 


lOU 


10-78 


0-00136 


lOW 


11-41 


0-00144 



Fom ic 


AcMic 


Prr^pioaie 


n-ButjTiG 


Valeria 


Acid. 


Ackl. 


Add. 


Acid. 


Acid. 


)-02U. 


0-OOlt), 


0-0013, 


0-0016, 


0-0016. 



^V M. The property of ttcids, iwaaUy called their "Htrength," 
depends npon their d«gre« of ionization, strong acnds uiiderjj:omg 

■ consiUeniWe, and weak ai-ids but iJight. ionization. Since the 
constant A' rises or falls in valuu HimultiiiicouKly with it und in 
independent of the conceutrution, it affords a fiouveiiieut mcaaure 

I of the Etrength of an ucid. 
TJm following abowa the valno of ff for certain fattr aoida: 
It will be noticed tliat formin acid has a greater value for K, and 
is therefore stronger, than its hntnologuL'E, u fact which oiltirtlB 
anolber example of the diScrouco iu properties existing botwoon it 
and the other members of tlut series. 
A CO neid oration of tho degrees of ionization for o()iial eone«n* 
trations shows that these acids are rery weak cempared with strong 
tniiienil acids like hj-drochloric and Hulphuric. When y = 16, 
^^th«n for hydrochlorin acid 100« = *ih-ho, and for acetic acid only 
^K2 • 073. it is obrious tliat lOOw is the amount ionized, cxpresfcd 
^^in percentage. 

Allliough the law of dilution ia genemlly n|iplical>le to the weal: 
organic acids, it A<ka not bold good for the sirauK mineral ncida. ll 
ban not yet b«eD possible to giro a perfectly satisfactory ex[)lauatkin 
F tliispheiiouuinuiu 



DERIVATrVES OF THE FATTY ACIDS OBTAINED BY 
MODIFYING THE CARBOXYL-OROUP. 

96. The riirboxfl -group may be nindilicJ by the exolutage of 
its oxygpn atoms or hydroiyl-group for other ulumonta or {iroiiiM. 
Tbia ia th« cue iu the cImsm of compounds dcacrjbed in thU 
section. 

I. Acid Chlorides, 

These are derived from the acidii by ropluccmDiit of the. 
hjdroxyl-grniip by chlo^nr^ oo that they eoiiUiin the fcroup 
— COCJ. They aro obtained from tho aoids by the notion of the 
chlorides of pbosjihorus, PCI, and PCI,, or of phoephorus oxy- 
chloridf, POCl,: 

ac»H.„ . ,. coou + PCI, = 3c\n„ . ,-coci + P(0U),. 

T\ie eauv witJi which the acid chlorides aro ooDV(>]-ted inli) the 
corruepoiidiiig acids i» a proof that the chlorine atom has rt^plaoed 
the hydroxyl-gronp. In the case of the lower members this can 
be effected by merely bringing them into roiitart with water. If 
the oldortne atom had entered the alkyl-gronp, this would not 
take p1a4-c, becauae an alkyl chloride Is uot decomposed by water 
at ordinary tvnijwraturea. 

The acid <^'htoride(i uf this oerieii. at least the lower membeni, 
are liqnlds with a ouffocHting, irrituliiig odour. The chloride 
corrcBpondinir to formic ucid is iioi known. A(xtifi chlnruh, 
C1I,C(>(.'1, fumes iu tho air. aud can be distilled it-ilhunt Oecom- 
position. It boile at ftS", and its spcoifio grarity is 1 • 13 at 0^ 

The acid chl"ri<icit. especinily aootyl chloriOe, nr« of gjMt 
service in delerniiniiig whether organic compounds contain 
hydroxyl, becaoite witli mich compounds they yield aeetyl-deriw 
tires. In this way they react, with alcohols, forming esters: 

RO| ir+^i |0CCH,= RO0C-CH,4.HCl. , 

The compound in which the presence of hydrosyl is suspected ia 
tested by sllowing it to remain for some time in contact with 

■ 14 



AaO ANHYDRIDES AND ESTERS. 



>»5 



acetyl. chloride, either at the oriiinary temperature or ntiiler the 
influciico of slight heat. To aeccrUin whether an acetylHMm- 
pound hu been formed, the product is subroittfld to analysis, or 
is Hiponifled . tn the latter awe, the presence of acetic acid proves 
that an acotyUderivnttve was proKent. 

Tlie nuiil cliIt)Ht!i-« aIho rvxcL wilb tliu iiiercai>laiis, with lh« forma- 
tiva of ncetf iHjompoutiiU. 



XL Acid Anhydrides. 

96. These are fonned by treatitig the iilknli>Kalt8 of aoidii with 



acid chlorides: 



oc cn. 



CH,-C0, C1 + Xa Q.OCCH, = 0<^^;^J]' + NaCI 



Higher anhydrides are best obtained by benting the aodiiim salta 
cf tbe higher acids witb acetic anhydride. 

The acid chlnridea may ix* liiokfd ii|>rtTi ao the mlied nnhjdridci of 
hyriroehloric aoid and nn iicid. a vinw nhioh tn Hnjj|>i>rii-d by thiMr for- 
mation from tbcee two acids in pn»eiico of jibospharus pentosidc lu a 
dehjrdrating-HRent. 

Mixed Huhjdrides of tli« fatty Koidd IheowolTes exist, aIthou(;h 
when diiUilled ili«y d«4.!unipu«e tiito tlie anliydridcx of ibe two acids. 

The lower memhera of this series are liquids with a disngreeahle, 
BufffMiating ofloiir. They are immiacible with water, and partly 
ou this account decompose but slowly when in contact with it. 
Aeeiic anhydride boils at 137°, and has a specific fpavity of 1-073 
at 'i<y. IJko ncotyl chloride it ts used in testJDg for the proeonce 
of the hyd roxyl-grou p. No nnliydridti of formic acid ia known. 

m. Eiters. 
07. Thcee remit from the interaction of acid chloridefl, or 
anbydrides, and alnohols ; 



CII,-CO[ Cl-f-H |OC,H, = CH,-COOC,H^ + HCl. 

They arc also formed by direct trontment of the alcohol with the 
acid, although extremely slowly at ordinary temperatures: 

tai.-COUli -f- HOC.H, = CH.-COOC.H, ~r 11,0. 

The speed of the reaction U much increaiiod under the inflneQCO 



Il6 



ORGAMC CHfMtSTRY. 



of heat. Kiitf>r)t nm further nbbiitied h\ acting upou iho silrer snlt 
of nil noit] witli lui ulkyi iodide. 

Tbe following is a rlianirt«nstir aud fretiuenti; used mothtM) 
for the preparation of thoce compounds. Dry hydrocfaloric-acid 
gas ia led through n mist iirc of absolute alcohol und thi> iinhyd roiiK 
orgiuiic auid. Aft«r fioiiiu limi- itic rwictiuii-mixtiire is puur<*d intu 
■watyr, whereupon the esier a>pnrat« out. owing to Its slight sohi- 
bility. Thv fonuuUoii of csti*i-« iii ihi« wity may be cxjOairied on 
the luisuinpLioii thut a vt;r>*siiiull ijUitiiiity of the hydrocliloiic aoiil 
anite« ivith the organic mid, walvr being eliminated, and a niinulo 
quantity of the ofid rhlortdo formed : 

cii,.coon + iici = cn.-coci + h,o. 

It is true that, for cnoh moleciilo! of acid eliloriilo formed in 
a(?c(>riiano« with thiri r(|Uatimi, an 4.<(|UivuIcnt <]uaiility of walei U 
produced, Kuftioieiit to leuonvert the chloride into the acid auil 
hydro<rhl(>ric a<nd. Thtre is, howrvci. such an infinitely grpntci 
numbur uf molecules of alcohol than of water with which llu- 
chloride can react, that tlui pro&aitiUiif of the fortnation of an est«r 
h very much greater than that of the regeuor&tton of the acid. 
Thid i^ttito of thiugd ootitinnca lu; long :i« the unioiint of nk-ohoi 
present greatly i>xcc-oiU that of the water formed; it ie mado to do 
80 by diu^otviu^' the orgiiuiu iicid In » tuige oxce^ of alcohol, when 
the object iti to obtuin llio niiiiiimiim >ield of ester. The forma* 
tion of esters is calle<l ealerijtcalion. 

The esters are colourless liquids of neutral reac^tlon, aad do not 
mix vith water in till proportions. Thoy are lighter than wHt4?r, 
moat of them having a BpuciHc gravity between O-SaodO-U. 
The majority aru churaL'terizeil by the possessiun of 8 vtTj agree* 
able odour, resembling that of fruit», a fact which finds practical 
application in their employment in the manufacture of fruit 
esscncee. For example, iMami/l-iaavitleratc {li.P. ViC) has iin 
odour of apples, el/i^l butyrate (11.1'. 121°) of pineapple, add 
imamylacettUf (B.T. 148") of pears, ami bo on. 

Tertiary nlcnliol« cnii easily )k> ityii [luwizoil fMCH llio ostofS by 
means of GftiOKAHO's alWyl-magnL-siiim-lialo){on compuuiids (BS): 

.OMgBr 

AililUiiin>protluac 



THEORY OF HSTF.RIFICATION. 



117 



The uddluoii-praduct ao obluiued nMiota with h bocodU molecule or 
the mitgneRium cmnpoiitMl: 

/OMffBr /OMgBr 

DecomiiMitiuti wiili water then yields the lertinr; alcohol : 

.OMgUr yOH 

K.C^H" + H,0= UC^tt" + MgBtOH. 

R. If. and R" = alkyl. 

98. The furmaliou of esters bus been oarefully invoitti|^ted 1>y 

Mveral chemists, first of whom wi'fp BKitTHKLuT and PfiAN de 

St. GiLLES. Tlieir researL-hts have sliowu that the reactiou 

betwvvn the lu^id and the aleohol ia nevur complete, eomo of 

botl) romaiuing uncombiucd. 110 mutter how luug tliv [irocceit has 

been carried on. When equivalent f[UiuititiuB u( u«etic acid and 

ethyl alcohol, for examjilu, ure UKed, the llnnl product tu such that 

fmm each gramme-inoleculo of ideohol and arid used, only two- 

thirdit of a gramitie-moIei.-tile of nil ester and of water are formed, 

while one-third of a gr&mme-mokcule of the alcohol and of the 

Htric] rpBpectively n-'raaia iincombliicd. The name limiting point 

is reached whon an estor and wat«r are brought into contact in 

cqnivixlent quiiTititica. A state of f^qiiiiibrium is nltimatoly rfiiehed 

Ixtlween the four i^iibstaucos, alcohol, a<!id, OHtor, and water, due 

to the rwersibility of the reaction (" Inorganic Cliemistr)-," 48). 

It may be repreHonted as follows: 

c.u.on + oHjCoou ^ on.cooc.n, + h,o. - 

The eqnation of equilibrium dodured in Ihid., 40 and 50, may 
be applivd to the formatioa luid docompoeition of caters. It is 

X-(;»-x)(s-a!)=i'a^. or (;.-:£) (5 - i) = JTx". 

where ^ \s the conoontratiou of the alcohol in the first iiietaiico, 
and q th*t of the acid, while x represents the quantities of water 
and of estor re«pootively present when the ntaLe of rrgnilibrhim is 
attained. ^Vll these tire eiproBBeil in },rninime-mole(nilns. and A" is 
ft constant. There are here two reactionB, with itpposite elTectB, 
biking plitce siinnltaiieouiily, so that all the BtaiemcnU already mode 



iiS 



ORGANIC CHEMISTRY. 



{Ibid.) are equally ajiplicubtc iu the presont instance. Whenp, q, 
auci A' are knowu, the uiiknowu i]i)aiitity z may be calculated. 

NuiDcrnuaobscrvntiona have proved that A'ia iqunl t« 0'3-* fnr ibo 
Rj'stfim otliji alcohol + acelio acid. When one granime-inolecuic of 
alciiliol (46 g.J M)d one i;raLuni«-iii»leoule of aoeiio acid (flO k-) are 
bruiight ItiU) cotiUtct, m tlila <^i« bnili /' niid 9 bctng equaC to 1, tbe 
equation is 

(I— *}'=0-25*\ or «» — |;b + J=0, 
from nhioh it follown that 

« = |. 
It follows (bnt ihU lyatcm in the atalo of eqnllibriiiia «onUUns 
i (;nimtnu-moleaul9 a3oobo1 + i grHmme-molecult acetic add -f 
{ j^amme- molecule water + f graniQio-iaoldcuJc esler. 

99. Several deiluctions can be drawn from the equation 

{p - x){q - x) = K:^, 

whii-h ha^l b(>en oBtaliliEhed by experiment lung previous to theee 
tbeoretieal dert-lopiDuuts. 

1. The c«U;rili<:al,iou \s approxiitiutvly ijuuiititativc tmly when a 
large vxvves of the alcohol is miavil with a very small quantity 
of Ihtt acid, or when a siuaU proportion of tlie alcohol is bn>ug;ht 
into (intact with a Inrf^c amontit of the acid. 

Putung the equation in the form 



X 



= A' 



q~x: 



it is crident that, tho qttnntity of tho alcohol [p) heing infinit^dy 
great, tho right-hand side = 00 . This holds good when q = z, 
that \i, when all this acid has been Roiiv^rtcd into «Kt«r. It is also 
true wlii^n thf ratio of the quantity of acid to alcohol Is infinil«ly 
great, the wKolo of the alcohol changing into CKter. 

S. Tho alool^ol and the acid cxorcigc tho sumo inflacnco on Iho 
fonnntion of eaters; that is, if one mixture is made containing 11 
certain miniber of acid moli^piiloH and » times as many nlcobol 
molecules, and another iu which the proporiioQS of acid and 
alcohol are rcTcrsed, then the number of molecules of acid con- 
rerted into ester in the firtit rn»c is oquol 1k) that of the molecules 
of alcohol converted iu the second. 




When p grnminc-moleculog of alcohol uro mixod with np 
gram nie> molecules of acid, th« ec]natioQ becomes 



HjuT«rsely, when np gramnie-moleculMi of alcohol are added to p 
^Kgramme-molacules of acid, we have 

BSnt 



•X up — z 



r fi — x' 




■r, 



< 



:iit thoGe two efjuatioDs aro identical, the Qrat being oonverted 

into the Becond by maliiplying acroM by ~ . 

3, The addition of a quantity of the ester to tlie mixture of the 
alcoho] and the acid at tlie beginning of the experiment has the 
s&ine effect on tlie formation of eeter as vroald be exerted by an 
«qniTa)ent <(aantitj' of water. 

When J" gram me-niolec'u lee of water or of eeter are added to a 
ixlure conlaiuiiig/j gramme-nioleculesof alcohol and q gnunme* 
olecules of acid, then in both caaea the equation becomes 

(p-x)(q-x) = Kz{x-\-r). 

lows from this that the equilibrium is influenced to the 
ie extent by the addition of water and of ester in equivalent 
qnantiticB. 

100. A typical application of iha principle of mobile ctiui- 
Itbriuui { "Inoi^unic t'liuniiatry," !J35) umy be iniidc in tlie caw; 
of the formatiun of eaters. Although (he velocity of formuttoii 

<i dc-coRipocition of estci-s ilepciitia grontly upon the teroporaturn, 
change iu the latter hus but vt^ry slight otToct upon the equi> 
libriom. At 10° the limit of esterilicalion h 6fi-2<(, at 220° it is 
Ol)*fi.<. In acrordunct' wilii t!i<- principle jiiNt natntioned, tliiii 
.traold not Iw the ciia» unless the lieuta of formutiuu of the BStera 
ere rery small. That they actually are so haa been eatablished 
ij experiment. 

101. The saponification of pgtere nndt'f tho influence of acids 
takea jilace in accoTxIance with the following equation: 

CH.-COOC^, + IL,0 = C]1,-COOH -f- C.H.OH. 




tao 



ORGANIC CHEMISTRY. 



The octiou of tlip acid which is here added ia Uierefore only 
catnlytic. U may tliuH be iiotcd that the preeenoe of miuoi-ol acid 
only Hccc1omt««! tho e:\potiitlcatioD, oJid that the same result would 
W obtainod witliotit tliie ticid. Uioiigh in a sjiace of time iuconi- 
pHr»h1v longer (68}. If tlie conceutralion of the ««t«r be C^, tluit 
of the water be C^ , and x the- quantity of e8t«r which baa nudorgoiie 
aapon ill cation during the lime t, then the reloci^ of wponitlca- 
tiou for each moment can be repieaeuted by the equ'atioo for 
bimolccalar reactione ("Inorganic Chemiatry," 60): 



ilz 
df 



= kiC\-^)iC,-x). 



a) 



If Ihe G«t«r is dimolved in a very large quantity of water, the con- 
ccDtrutiun C, of the wnli'r ig only very 8llghtly altered by the 
saponitication, HU th»,t it may be included ia tlio constant. The 
equation ia theroforo fliniplilieil tn that fora iininiolecular reaction: 






= k,(C - x). 



(2) 



The saponitlcatioD of eatera by bases may be repreaenteil as 
followa: 

CH,. COOCail, 4- NaOII = CH,- COONa + C,UjOiI. 

Since iu this cane the reaction in a binKtlouular one> uquation (l) 
hoMt good for it. 

The Tfilocity of fiaponiflcation of Mter« by acids dependB laigvS|:j 
on the partirnlur one ii»otl. With stroikg acidii tiie proccsa ill 
rapid, and bIow trith weak ones. It has been thown that the 
Telocit}' of HapotkificiLion in conditional upon the amount of elec- 
trolytic diiMnciation ot the arid employed. Frnm this fact it may 
be cotieluddl that the aitponifyin^ action is due to the bydrogeo 
ion, eince tbis is common to all acids. The velocity is very iimch, 
greater for bftsan thiin for iiciil^ ; thii£, for dilttto (dccinormul) 
kolntioDs of eauKtio potash and hydrochloric acid, the ratio of the 
velocity conHtjtnts K" fur the uipDiiiticntion of mrithyl acetate h 
1360:1. The velocity of saponification in the case of Imma aldo 
depends upon thoir electrolytic dieeociution. Ammonium hy- 
droxide, for example, which ie eoiiiiiderubly lc«8 ionized than 
caiietic potash or caustic soda. snpoaiScs much more slowly tli;in 



TmO-jtCtDS AND ACID AMIDES. 



131 



y coin 



die latter. It a therefore tlie hytlrosyl-ion, oomraon to all tlie 
buses, wtiicli csiiees Mi[ionificalion. 

1q the t(.i:hi)i(:ul fiaponiltciiiioa of f&ts with slaked linte (91) a 
much BmaUcr luiiotint of tliia bnso is uaod than the equivalent of 
llio qiiuntity ol ncid obuiinod ; the Bitponiflcntion U nevertlivleas 
coiii])lou>. This is dtio to the fact ihni the higher fatty ucid^ are 
verjr weak, ia consequence of vhicli tlieir stilts undergo psrtUl 
rol^io diaaociation. ThiiH, notvrithetAnding the «:toe^ of 
id. there is always mnie free baae (hjrdroxyl-ioiis) preeeat> bj 
which the eapouilicatioa is effected. 



Xtttrlllcttloii at Ttintxj. SMandkrr. snd Ttitlarr Aiooholi. 

lOS. MKNitc-uLiTKiK Liw inveatigated the quantity of Mter fomiDd 
when primury, sooondsry, iiiii] terliar> alcoht^g rcnpectivelf arc boated 
Willi An equivalent quantity of a^ioua acid In sMil«d tubes for one hoar 
at 154*. He haa shown that tho poroentagD-tmnibors obtaineti for ail 
the members of efteh clasa of aloolioU nre nearly the Hamc, althmigh 
ihpy differ wtilely for ihe daaseo Ltictiiaelvefl. T>iii» about 47* of pri- 
mary, about a2« of wfloiidary, and only about l..Wo( ivrliary Atcrthots 
are converted iiilo t»Ci'nt. Thiit afTonls a muiiua of determining to 
wliieb of the three ata»>(« a givsu alcohol belun)^. 

IV. Thio-aeiib. R-CX)'SU. 

103. The thio-acida are frtrmied l>y Him IntiraflCioa of aold chlorides 
and iMtaasium aulpliydrate, KSii, a mt^ihod of formation whicti is a 
proof of tbe ooitsiituiion itidicnlt'd aljove. Tliej' itre liqttitls nitb a 
most dfangreeablo small, and when heated with salts of faeary tneiaU 
readily yield acetic a^id and ttie corres[>ondiiig metallic aalphide. 



T. Acid Amides. ('Jl,n ^i-CONH,. 

204. Acid amides arc forniuil by the action of ammoiiia on 
•ciJ chlorides or unhydrideA. a method which atfords a proof of 
Uieir constitntioD : 



C,H,.,.-CO p+H |yH.= C,U,+.-CONH,-f HCl; 
C,IIb.-,,-CO-^ f. 1 HiMH, _ 2n ir .C0\fL4- H f) 



Aeid amidea aiie also formed when tho ammonium »iU»: or tho 
fatty aeidfi are Btronjrly healed, or when the Bwlium sails iire dis 




tffS 



ORGANIC chemistry: 



[tUlod with ammOQium cblonde, one moleoUo of VAt«r 1>«iig iplif 
off: 

0„K,„ . ,.C0l0lim,H;| = C„H,„ . .-CONli, + 11,0. 

It has alreadv b«»n m^ntiouod (86) th«t when tli6 nitrilos uxt 
warmed with actdn, two molecules of wftt«ir aro tAlcoii up, with 
ifbrmation of tlio ooiTespoiiding iic'tilg. This rractioii can be m 
mrriod out — for example by dissoliriug thv nttrile in concentrated 
sulphnric acid^^thnt only one molecule of irater45 added on. By 
thU means, &micle6 ar« obtained: 

I The acid amides are therefore intermediate products in tlje con- 
Toraion of nitnleu into acids. Amides yield, on tbe one band, 
nitrileK by eliminatiou of wat^r, by distilling with phospborus 
pentoxide for example: mid on the other, the correq>onding acids 
by tuJditiou of the elementB of water, on boiling with dilute acidii 
or ulkniis. 

Tbc acid amides are also formed by the action of ammonia 
npon eaters: 



cii,. oo| oc,H, + ii |Nn, = cti,-coNir, + c.h.oii. 



The acid amides ore solid, crystalline coDiponnds. with llie 
Exception of /onwtfmu/e, H-CONII,, wliioh is liquid. The lowtT 
memberg ar« solublo in water, and odourlcsc; when pure. Act- 
amiJr. C1I,.C0NJ1,. melt* at ifi", and dietild at 222\ Some 
spcciuifiis have n strong odour suggestive of tho excrement of 
mice, due to eliglil traces of impuriticB. The reinarkabty liigh 
boiling-point of this subatance is worthy of notice. 

There iii b great difTcrenco between the behaviour of tbe acid 
amides and tbe aminoH. Tbe bond between carbon and nitrogen 

in the group — C-<j-j, of the anides is cosily broken by boiling 

with acids or alkalis, whiob is not tho ease with the bond hetwcen 
carbon «nd nitrogen in the nmincK. Further, tho bnaa pmiiertie* 
of ammonia are greatly weakenett by the exc>iang8 of one of iu 
hydrogen atoms for an arid rudiclc; and although aaitii of acid 
' lonides do exiat, they are decouipos^'d by water. This it the cftac, 
for example, with acetamide hydrochloride, CH,-CO-Kn,HCI, 



AMiDOaiLOmOES. MMOETHeaS, ANO AUmWES 

wlueh i» TormeU by pasaing dr; hydrochloric -acid f^nA through sn 
otheKal solution of scetainidc. The aoid iiniidcs even {MttueHs 
acid pro{iQi'titiS; thuB, an nqtieous sohition of acctumide dis- 
solves luvreuric oxide, forming u compound with the ff^miulB 

'Tlie behaviour of tho ainidos and aminuti IowutUb nitrous uoid 
ts analogous, the corresponding acid^ and alcohols rospectiToly 
being producwi by exchange of NH, for OH (72). 

^H The nmittea can bo convortMl luio tho luniuea witli oii« carbon 

^^^^HlOQi l«flB ia (he ido1«c«1o, by (roMitnei)i with bromioe and cnuatic 
^^^^t tooiaah^ or by diBtilling wuli blL-aching-itowderand aJalicd liiix-. ii guod 
^^^^B IBCtbod of pr^pnririK the primary ninines free from tbe cnrrespDnd- 
^^^V tug secondary And tertiary dcnvatives. In tbit w»y, htUyrami>ie, 
^M OB.-CQ.-Cil.-OONn., yields propylamim. CIt,-CII,-CH,-Nii.. 
^1 The theory o( this rcaclion will be expliunfid IbIit (S«). 

" 105. In addition to tliodt-rivativos ulreodydcecribcd. there arc 
othort which cart bo obtain<Hi from tho anids l>y substitution in tho 
oarboxfl -group, some of which are doeerihcd below. 

Amido^htorUita are formed by the action of phoaphoriu p«nta- 
cblortde dei the ncid Amides : 

ROONII, + PCI, = K-OCUNII, + POCl,. 

is aro only elablo when one or both of the hydrogen 

df An amiiio-Kroiip. NHi, are replaoed by nlkyl-rAdJcles. 

FKiey yield imiuo-olUvridta, KCCI:NH. by tho spUttiog off of one 

tholeoule of HOI ; Ihr numv compuuode are formed by lliu addition of 

HCI to ntlrlli>)>. 

Imitto-tthcrt have the constitution R-C^" ^^,,, derived by roplue- 

rffienl of tht^ doubly-linked oiygen of the c^arboxyl-group with the 
'loklo-fcrftiip, Nil. Tlivy arc obluioMl by combiiiatiou of alvolioU and 
nUrlle* und«r the Inllueuce of dry byclrooblorio-iuiid gas : 

fimino^UierB form wclUfirysiulluwd fuitta with hydrochloric acid, 
fliich arc eonvertwi by treatment with ammonia into the hydro- 
chlorides of the amUUnta : 



'oc.n, 



■NU. 



, The amidioes are unstable iu the free &tate, but are strongly moot^ 
Ibaaic aud form stable salts. 



J 



134 ORGANIC CHEMISTRY. 

Amidoximea are addition -products of the Ditriles with hfdrozjl- 
amine, NHiOH : 

R-CN + H.KOH = E.0<§2^. 

They yield aalta with both acids and bases, and, with an alkaline 
solution of a copper salt, give a flocculeut, muddy-brown or green 
precipitate. The latter affords a characteristic test for them. 

Acidhydrazides are formed by the action of hydrazine, HtN — NHi , 
on acid cblurides or esters, and therefore have the constitution 
R-CONU-NUi. They are coDverted by the action of nitrous acid 
into acid azidet : 

R.OONH.NH, + HNO, = R-CON. + H,0. 

These are volatile, explosive substanceB, some of which flrystaUize well 



/ 



AISEHTSES AID KETOIT^. 



106. Tho nldchydcrt and ketones havo tliu general formula 
.0. Thpy are formed hy the oxidation of primary aud 
l»ry alrohoU rcspiHitivcly. Both ihwe classes of alcohols 
hare tlic general fonnuju C„il,B . ,0. wi timt the itactiou m each 

»C(Wq consists in tho rcmoTal vt two hj'drogcu atoms. 
On farther oxidation, the aUiohydos take np one axygt;x\ fttom, 
forming tho eonwpondiiig ncids oontainirg the name nnmhor of 

■ carbon atomn. Thng C„H,nO in ronvortpd into CoH^O,, to that 
•n nldehyde it an intermediate product in the oxidation of an 
alcohol to an acid : 



f .,H,„ . ,0 - 

CrtiUKry Ak-uliiil 



(■Ji„.o 

AliEpljyilr 



ojr„o,. 

lUKI 



Aak 



The constitutional formula of a primarr alcohol ii OcH^ ^ , • OH,01I ; 
mi oxidation thin yieldn an afid CnH,u , ,-COOH. Sinoo the 
aikyl'gnniji ('„H,„., iK not altered in thU reuction, it must he 
present in the aldehyde. Hence, it follows that the two hydrogen 
atoma removed from the alcohol by oxidation must como from the 
.gronp— CII.OH. 

There ftill remain two poBBibIc structural formula), 

RC<2' »nd RC— on, 

,of which the eocond containa cither a divulent carbon atom or two 

lioldngB, vbich makes it very improbable that it is the correct 

jrroiitn (17). It iihonld moroovor he noticed that it con tains « 

liydroxyl-gronp, wbor(>iis the aldehydes have none of tho properties 

cnliar to mibHtancoit containing thia grnup. They do not, for 

Bxample, yield esters or ethers; and pliosphornn ppntachloridc doM 

laot n^jdace Dil by 01, Init cuueve the exchange of tho oxygen atom 

For Jum oldorinc atoma. 

Since the second formuln is not in agreement with thd proper- 
of the nliohydos, it follows tliat tbo Srat is tho <->orrect one. 
This view U HUpportod by tho fact that tho aldehydes are 

"5 



ORGANIC CHEMISTRY. 

formed when acid cbloridee dissolred ia moiat ether are acted on 
wiUi godiiim, tLe chloriuo atom b^ing replaced by a hjdrogtfQ 
atom: 






.C,li, 



c< 



H 



lhitrnld«h)rd« 



The ai<Uhyde4 are th«re/ore ccrnpounds which ctmiain the group 

107. It was stated iti 106 that the ketoaea are formed bj,j 
the oxidtttiou of lUo soooud&ry alcohols. The ketouea likeviMJ 
lack the propertiee puculiar to hydroxy! -compouudb, which prove*' 
that the hydrogen atom of the hydruxyl-group has b««u removed 
by the oxidation. Lcuviug out of acoount th« iKMsibility of the 
selliuf; free of bnudi*, the rvmoval uf the eocoud hydrogen atom 
can ouly take plaoe iu one of two vaye — from the same carbon 
■atom to which the oxygen is linked, or frnm the olner oarbon 
patom. ThiB cut! be illutitrated iu thu following; way, R and R' 
reprmeDting tdkyl-groupa: 





I. 


U. 


CH.B 


CH,B 


CILR CHR 


CHOii 


— CJO 01 


1 \>^ 
CtlOU — CH 


OH,R 


CE,R' 


illjR- CH,R' 



For reaeoDs analogone to those rtatcd in the caso of the aldehydes, 
formula I U more probable than formula IT. The prodiuns 
obEnined by tlie oxidatiDn of the ketones .ihow that their conslitti- 
tion \e in fact repmaented by formula I. 

The general formula for a secondary alcohol is 

R.CiL-C;^CH,R*; 
NOH 

from soch an alcohol two acids, R • U H, ■ COOl I and U' ■ OH, • COOH, 
are obtained by strong oxidation, the carbon chain Iwing broken 
in some oF the molecnles to the right, and in others to tlie left^ of 
the CnOH-group. A means of determining what alkyl-groiipg 




ALDEHYDES AND KETONES. 



an Knk«d to the group — — ia any aecoiidary alcohol is afforded 

Oh 

brthis renction. .Since ihe imme auida ure oMatned by oxidising 
k«(onea, wliich are timmselvBH produced Ijy Kubmitliug secondary 
atcoholfi to gentle oxidation, ii follow* tlial the aJkyl-groups of the 
fivK-ondxry alcoliols muitt exiHt uimhaugui) iu thu ketone. Henco, 
sucli a Btrnctnre as that rt-preBonted by foroitila II is ciduded. ao 
that forniula I miirt bo the correct one 

Kttones tkfmfore contain the yrm»p CO, called tho earbonyl- 
group, liNktd to two airbnn aiovm. 

AldfbydcB may he looknd upon m ketones in whioli an alkyl- 
group hiu be«u replaced by hydrogen. 



d 



VomeQcUtarc. 

108. Thp nnme aldehyde is derived from n/(cohoI) dehy<l{ro- 
genatiis), tluit is, ''alri)ii(d frnni which hydrogen line bcseu uli- 
etracte^l." Tho wonl kptotic has it« origin in Ibc name of tbo 
first membt'T of tiie ecriM, oettone, CH^-CO-CH,. 

The aldtihydoti are named after the correspouding iicids: 
formaiiIekjfd« H-CHO. tu-ftaUh-htjde CHj-CFTO, jn'opioHiihleh^ftt 
C^.-CHO, vaUraMfhyde, C.H,-CHO. etc. 

The kutonea derive their names from the alkyl-grnupH whirh 
tbcT coiitatii: itiiurthj/Ucciune CIl.-CO-UU,, iMthi/ijirojfylkfliiM 
CH,-CO-C,II,,etc. 



M«thod» of Formation. 



100. There arc lifveral nietiio4l«, other than the caidBticm of 
alcohols, applicable to the pre)mration of Wlh aldehjrdM and 
ketoue«. 

I. Drv disciUation of the ealts of tho fatty acids, caloiutD 
tiootate violda acetone: 



CU,.C0lIJ3i 
CH,. COOca 



= CH.-CO.CH, + CaCO,. 



•c« = iCa. 



1 28 



ORGMWC CHEMISTRY. 



Axi altJehvcIe in produnecl by the distillstion when an equivalent 
(jiiantitv oi a formate is mixed with the mlt of th« other fatty 
acid: 

COONa 



o,n,.co 

H 



= O.H,-0^g + Na,CO,. 



Loiitly, mixtd ketonta btu ubtuinvd when a mixture of the salts of 
two difier«Dt fatty acids, except formats, ie diatillod: 



Id tbft laat two rtuctiooB the produut cootaiua tbv correspoudiDg 
rimpte ketones in nddillnn to ihe iildeli3'(le or mlxtMl V«loiiv. TtiUK. 
in tbe exAinple viivtn abovv, diiiivDivlliclotiv uud dictfa^llcvtone ar« 
also formed. 

Givea lUe slruoluro of tlio f«lly acida, the method of formutiou 
JuM dewrlbed could be put forward tM. a proof of llie conslitiiiioii of 
thoiddchydcB and ketones, if il urem itot tliat thu reaction only takes 
place lit liigh lunyjvntlures. SiiicL* ;iiidvr sucli oooditioris orgaoJo 
flompouoda frequently undergo chai)Ko» of ^truolure, more especially 
al t)in mflmcnt of formation, nuoh pjfrojrenetic reactioiiA caimoi be 
ngardod as fumiabing couclusirc evidenoe of the oon«tilution of a 
oom pound. 

2. Aldoliydea or ketones (ran W oUtiiincitl from romjioiiiKlei 
containing two halogen atoms linked to h ginglo carhon atom, br 
heating them with water: 



CH,.CH!C1. + HJ0 = CH.CHO + aHCl. 



Kthrllrfoav irblurMa 



i 



3. An important method for the preparation of Icetonoe, but 
not of aldehydes, is the interaction of neid chloridefi and ainc- 
alkyl*, or nine alkides (82). When thn two aub«ti»rirc» are brought 
together, an addition-product is firat formed: this ran only result 
throngb the changing of the double bond of the oxygen atom into 
a single one: 



C„I!,.. . , . C < ^, + Zn < ^H' = CH 



•CI 



GH, 



/OZuCH, 



iQ is (onnvd when this adilition^product U treatetl with 



■ >CI Hi 



,lI^,,-CO.CU, + ZoO + CII. 

+ lUM. 



^ 



h 



llOi ScTeral properties rommon to the nldchvilce and ketones 
d*]icnd on their power of forming addil ion-products. This pow*r 
1ia< its ori^n in tho double bond of th« oxygen atom, the conrer- 
Kon of wlii<>li into a iiiijji;le buiirl svl^ free n cHrbon and iin oxygen 
linking. This etiabU'« tlie aldebjdeK and ketoL^s to form additton- 
pror)nrt8 with the following elements and coinponnda. 

1. Hffilrtt^ni. — An ttdditioii-prixluct is formed by the action of 
«odiiim amalgam on an aqiitions ^lution of thf aldehrdea or 
ketones; or, if they are insoluble, on a mixture uf them with water. 
PrimaTT alcoholo are Conned from aldehydoB, and secx^udary from 
ketones. 

2- Sodium hi/drofftii sulpkHr. — Wlien aldehyde* or ketones are 
shaken up with a verj' eoncentrated solution of thin eompooud, a 
crystalline udditiou-prodnct \a obtained : 

C,H..C'<° + .\aHSO,= C.H.-( <X \a' 




U 

compounds is assigiiwl the constitution indicated by the 
"fonniila, because they are very ea.fily converted hy the aclioa 
of dilute acidn or Bodiiim carbonate mlntion into the correopond- 
iug aldehydes or ketonee ; in the ciue of th» higher members, mere 
aolntion in water effects this decomposition. For this roa^ton, it )i 
highly iinprohablo that thero is n direct bond between sulphur and 
carbon (67). The acid sulphite compounds — Bometimes incor- 
rectly callo<l bisulpliile pompouiuls — fiissoWe readily in water, but 
ore insoluble in very concentmUid ootutioQA uf thu ucid eulphite 
iteelf. 

I The ketones du doI all give these wlOitioii-prwIiicir. Tliey ant 

moat readily obtfli nod iron Ibosc eonHLttiing ntic mctliyl-graiip dinwtty 
linked to carbonyl, or melhylketones. 
Then» of acid eiilphite i« often exceedingly aen-iceable for the 
nriScation of aldeliydcs or ketones, or for Bcpomtiug tbem from 
react ion-mixtn res. 




IJft 



ORCMSK CHEMISTRY. 



Z. Uytlroeifanie arid. — When aa aldohydo or ketone la hroagl 
into crjtilu'-'t wii}i an iiqutxiUB wlution of hydroojuiic acid, cooi> 
Unutiaa taktw piucc: 

Tlili la H very itnportntit iijiitlie«i8, beranm the liydrox;<ni[rilea 
tliiiA fnrmiiil rjiii Ik* converted into hrdrnxT-wids hy mponification. 
Thi» ttlTonlft 11 nieiiiis <it ByntliBBijtiDg compounds of the latttr claaa j 
(188, 6). 

111. Willi (iiticJK.vni>'Ef alkyl nmfpiesium h&lidea (82), ftldo-, 
liyrli'H ami ki'toima form luIilitiuu-pruiiuc'tB, wliich, on treattnest 
witli walor, vii'ld ruiipt>ctlirtily aoeoudHry ur tertiary alcohola: 

H 



H 

S«COM(tI 



RO?. + H'MgI = RC^OMgl. 

AttMir<l« AddlUan-proiluot 



SII.O = 8RCH0H- R' + Mgl, + Mg(OHL ; 



AMlUaa-pnMluol 



oh; 

AmMim 



aHS'>l! < cu ^'*'' 4- m.O = a(CH.>.COH + M«Br. + Mg<OHV 



TVimcUij Icftrliluol 



118. Otlu>r proprrtii'tf commou tu ti)iIi-hTdt» and k«toQc 
ujwtt thi> fact tiMt thf doubly- litikod oxygtn atom can be ex< 
for otliur «t»viiw or groiijia. 

1. FktigftJknrtit jmtlarMhritii n>plRt.<«« tho oxrgeo atom ^ tvo 
vhl(iriii(> atoms. 

j. Hjfiimijilamin* Rttcta ia aroonLuico irith the 
vqnation: 

Thr conpowHls Uius fortiMd baw tbe ^oenl mm? ani 
calM mUtMtmn vb«K tber ar» 4enT«d fimn a HatT i ta , 
Jt»tmnmn vben deriTcd (ran kefODes. Tlut 
gmrnA appUcalioo. The otiiDia are citKar i 



lA 



MLDEHYDES AND KETONES. 



U» 



» 



orliqn)ds,and posKosB both acid andbiutic properties. When trentcd 
vith bases, tho hydrogen of tho hj'droxyl-group in replaced by u 
metal; mth ncids, addition-prodQcte arc formod, the reaction 
boiog similur to the production of iimmonium suits: 

Acolollme tijilmcbitirlilo 

Ou boiling with dihite hydmrhluric acid, the oximcs tnko ap 
ene molecule uf wuter, yielding hydruxylumLtte, and tiithor an 
tliloliyde or a kutoue. 

The following is a proof of tlie oonsLitation girca above for the 
OBimes. Tbero can b? no doubl ihat when hydrosyl amine acta on a 
lioioiift or an aldehyde, coiidaiisatioii lakes placo wilh diraiiialioii uf 
till' vaU>r funned by ihe union of tlio hy(iroj;[i'n of tlir* hydrozylaitiino 
with ihc oxygen of \hv carbitnyl-gniiip, bL-oniinc, if tho alkyl-groups 
tonlk pnrt In tlia rtwctlon. ibc rcgunonitioti of ttio aldAliydo or ketone 
would iiot bo so readily effected. Tbc po&siblo Btniotural formulra 
for the oximea ar« tborefura reduced lo tvo : 

I. n. 



HO, 



>C|0 



> 



>C=NOa and >C 



II 



II 



> 



•<Jb 



The oximoa contain oub hydrogpti atom rephccablo by an alkyl- 
gnap. When audi itn alkyl-oxime is boiI«d wiili faydroohlorio acid, 
there \t, formnd, in addilion lo the aldehyde or ketone, an nikyl- 
hydroxylatnlne. This hn« thi^ eoniititulion HiN-O-R', boeati&c nn 
beatinj; it with hydriodia auid, tlm nlkyl-^roup ih nplit oR with furmii- 
tioD of all alkyl iodidt-, a rBautioii which could not ttiku placo if the 
alkyl-gmup were directly linked to tho niiroK^n atom ; sinoe, if lliis 
were the onso, nn alkyl-nminc woulJ of nectiwdty bti formed. For. 
mula n ia Lhoi^fora excluded, aa rcplucomont of tbo liyilrugen alum 
in its NOH-gruup indicates the formation of a oompound containing 
an alkyl-groap dtrccllr linked to a nitn:^n atom. 

Energetic reduction converte tho oximes into amities; 
R,.C^K01I + 4H = R,CNn, + H,0. 

H 

The aldoxlmes are readily tranaforniBd into tho corresponding 
nitrilus by tho action of dL-hydrutiug-ageuls, snch as acetio 
anhydride: 

aU^ . , ■ 0=NiOU — C.n.„ , . ■ CzN. 



AlDliHYOES. 



*53 



I 



&LDEIITDE8. 

lis. Id addition to tboKc mvutionod ubove (110 to 112], which 
the; share vith kotonce, aldehydes posaoes th« foUov^g properties 
peculiar to thcTuselrcR. 

1. Tliey form iiddition-prodiicts with ammonia. Thas, a(>«t- 
aldehTdc-ttmmoniik is prodncecl when aRimouin reavt« with weXr- 
aldohyda: 

C,H + NH, = CjH^ONH,. 

AoetmlJehrde Ac«tAlilab)'dB«miiicnUk 

It is pracipitated in the form of white crystnk wiieii diy aromnnia- 
ga« is pssm^] into a Holiition of acetaldehjde in carefully dried 
«t her. ami is rerv soluble in water. Acids deconipoab tht- uldu- 
■ hyd«-aminonia compounds intothvir romponent-s; caustic potiiab 
u noable to effect this dMomposition. 

H Tho molecular formiilii of ac^taldehjrda-ammonla at ordk 

^^^^ tenpentttirea is thr«« timea tliftt of its ciu|iirical foruiulu. 
^^^^dried over nulphurio acid. It loses wat«r easily, being oonrerMd inlo 
^^^B(OHt'CIINIl)i, which in a polymer of ethyUd«no>tmine. 

■tiun w 



2. Reaction with ulcuhoU. Aldehydes are oapahlc of oombinn- 
Etiun with two nioleculee of alcohnU, with idiminHtton of water: 



cH.-cv,' + ;;i-;;;;-cn..c<^^^;;;+ii,o. 



,0 



nioo.n. 

HOC. 






Theae compounds nr^ rolled arttah. They are readily formed ly 

the addition of thv aldeliydtt l\> a \ii doltiliou of anhydrous FICI ui 

ttk-ohol. This reaction ie not complottf; it is limited by the reverse 

one. nnof water, acting on ut-etal, causes the formution of aldehyde 

d alcohol, liolh foriimtioit and deeompOBitiou of at;etal are 

Dsiderably accelerated by the presence of a small quantity of a 

itrong minernl acid, which uct« hero a& n powerful catalytic agent. 

The aoetalH arc lifjuidii of aruiiiittic odour, aud distd without 

eeompoeitJoo. They are not atlwhed by atkalie, but are tiplit up 

ly wcids into the coinponnda frarii which they were produced. 

'his latter projwrty further cKlabliehes the structure gi»eii above, 

cording (o which the ulkri-groups arc linked to the aldehyde- 



^^m 



>34 



ORGANIC CHEMtSTRY. 



residue by tneann of oiygeti, ninoo a carbon l)ond could not nanally 
be broken in this manner. 

3. Additton-producta are obtained with avid anhvdrides; 

cH..c'^ + 0{C0CH,), = cn,.cH<g^:2^U|. 

AoMk wthj'drtj* 

Theftp roRiponnds, whicti are atialogons to the iicctaK am AMiilj 
decomposed by vater, and still more eoail; by alkalis, into tlie 
oonvepondtng acid and aldehyde, 

114. The al(iehyd*8 further pos»e«e th© power of pombininf.' 
with thomsplvos. This X9k«« place iu two ways. When a few 
drops of concentrated mlpharic acid are added to acetaldebyde, a 
liqnid boiling at 22°, it is ohnerved that the mixture betomps 
vurmi and eren begins to lioil violently. At the end of the re- 
action a colourlesa liquid is obtained, similar to the original one. 
but boiling about 100° higher, at 134'. The empirical fvnniila 
of llii)S compound is tli« same 9* that of aldehyde itself, C,H^O, 
bat ita Taponr density ia three tim«w as great, tv> that ii has the 
molecular formula C,H„0,. This rompound, ^Htraldeh^ile, is 
readily oonrerted into onlinar)* aldohyde by distillation with dilute? 
eulphnric acid. Thig is another example of a reaction limited by 
th* rcTorw ono: 



C,H„0,. 



3C,H.O. 



The e<jni1ibriiun reached must be iitdependent of the nature of tha 
acid, that ts. of the cstalytie agent ("Inorgaoio Cheourtty." 49). 
This has been proved by experiment in this caae. The aame state of 
eqaitibriam most be rc«ched without the aid of any catalytic agent, 
bat the ractiou then proceeds so slowly that it has not yet been 
possible to prove thia experinieutally. .V diret^t linkage between 
the carbon atonu of the thive aldehyde molecules which hare 
united to form pantldehjde is improbable, bat a linkage throngh the 
oxygen atoms mart be aosumed^ becaiiiJe a accounU for the eue 
wrtb which tbc molecule of panUdehyde am be split npL It is 
cot attacked by sodium, and therefore cannot contain brdroxyl- 
^rwpf. All the characteriftios peenliar to aldehydes ue wasting, 

dwviDg that paraldehyde does not contain the group — C^n* 



ALDEHYDES. 



'3S 



The following coustitutiotiul fonuak best expneses theu proper- 
ties: 



CH,. 



n/^\H 



^(/ 



COH, 
A 



H 



The linbing together of two or more rnolet^iileH of n Hiibstance, 
with formation of a body frooi wliicb tlio origiiiftl coiii]toun<l uiny 
be regenerated, is calleil jiolifinn-izatioii. 

115. The union of tlie alileEiyde molecules among themeeWea 
takCD pluco in a dilTcrciit way when n ililiite solution of an alkali 
is ncMod to nn ikldehydo. When an aqueons solution of aoetiilde- 
hyilo is wanned with caustic potash, tho lifjuid boconies yellow; 
after a short time, reddiKh -yellow, ftraorphoug mastses are pre- 
cipitated. The aldehyde liiw re*inifitd, and the reddish -yellow 
snhetance formed iB (tailed aldshydf-rcsin^ When, however, di- 
Inco caascic potaah (or sodium acetata, xino chlori>(!c. etc.) is 
addc<l to acotaldohydo, a eitbetimi^o ia formed having the ^ittne 
empiricnl composition s^ aeetaldehjdo, hut with double tho 
molecular formula, C,rT,0,. This compound is called atdol; it is 
a liquid, distilling without decomposition under diminished 
prcfsiire, &nd reiudity undorgoing polymerization. It possesses the 
prop«rtk« peculiar to tho aUIchydci, yielding on oxidation, for 
pxnmple, an aeid with the fame numbor of carbon atoms. The 
icid so obtained has the formula C,]I^O,, and on investigation 
prorea to be an n-hydrnxybutyric acid, that \s, ii-hutyrin acid m 
which one of tliu Il-tttoms of the ulkyUgroup has been rfpltttinl by 
hydrosyl. It cuu be converted iutu butyric uctd, wiiich tuntutna 
ft chain of fonr carbon atoms, proving the prcscneo of such n. chain 
in nldol. In thig ea»e, tlio linking together of the uliielivdo 
moteciitcK has been etfected through the carbon hondx, a further 
proof of which is that aldol cnnnot bo reconverted into aldehyde. 
The following equation reprofents tlie linkiug together of tlio 
aldehyde moleuulua to form aldol, the formula given for which 
accounts for its properties: 



,H 



E 



,/ 



n 



CH.-Cl^+nOH,-C^ =CH,.C^CH,.C, 



'0 



'^ 









136 ORGANIC CHEMISTRY . 

In iiddiliou to the nbuvi- oii>liiiiitlioti of llic formation of al<lol bf 
tlw <?otjil>iii»tioii of one of llie byilrogen atoms of one aldelijrde mole- 
cule with thi! uxyKirii ;iiom of uiotlier (o form Iifdroi^l, it might lie 
cxplAind by n^umiiiK that an aldehyde molecule unitvd with a mole- 
cule of WBli-r, formiog an nddii ion-prod tict which rcAoUirltli b Moutid 
iQoleoulo of aldebydo with eiiutuntlo'D of wntcr 1 

ti 
CH.-oJ + H.O= CII.C<gg: 

™ ^<on H 

• | OH + H lOHfCHO = CH, C<iJH\.<;nn+ H'O- 

AMo) 

The formstioD of such aa addition-prodnct with aubscquent «ltuiiuA- 
tion of the urxler, is frequi'iilly Assumed to taifv pUou, \\i\i assuiop- 
tion oftea aiFarding an ox plan at ion of the course of rvnctiooe. This 
has been experiDieo tally veriflod in a few caaes. 

Aldol U both ail utt^oliol and uti uMeliyile, lience its name, 
a/i/(eb}'deiilc«]i)of. Tlic linking together of molecules through 
oarboD honcts, as in the foroiation of aldol, with the prodnction of 
oompoundB from which the origitia] enbstauee cannot b* rcgOQ- 
erat«d by any 8im]de method, la called comtenfafiitn. 

It is probxote tliat aldchydv-rmin is h product rMulting from coii> 
tiouod cofldciLsatioQ of the aldol molecules with elimination of 'H-atcr. 
jual as aldol it8«!f «a&lly loses one molecule of water when heated, 
with formation of crotonaldehyde : 

OH, OHOHCH.C)! - 11,0 = CH.-CH:CH-C^. 

Ora(onnl(l«hjd« 



Test* for Aldehydei. 

116. The following toatsaro used for tho detection of aldehydeti. 

1. liesiiiiflcatlon with alkalis. 

3. Reduction of uii amnioniacal silver solution. This solution 
is prepared by adding exceiw of caiiMir potaeb to h eotntion of 
ailver nitrate, and tbeit animoiiia carefully niilil the silTcr oxide 
procipitatcd \t just disdolrod. When this liquid is brought into a 
ditnte aqueous solntiou of an aldehyde, and the mixture warmiod. 





ullie Mtror is deposited ou the sidea of the tube in the form ot 
mlitul tuulallic; mirror. 

3. When aldehyde id added to » HQlutioii of magenta which liu 
l>ei-n dcH^uIouriisi'd with tsutphurouH ucid, the red colour is rcAtotcd 
bj thu firrtnaticiii of couduUKutiuu-producte. 



Poniwldehyde, ]T.C^§. 

117. It wiis mentioned iu 8S that formic acid, the first mom- 
bcT of the homologous McricB of fatty ucida. ha« ocrlain proi>crtica 
uot poaaeeeed by the lii^her mcmhers. FornnUrleliydv ufforda & 
striking exAmple of this phenomenon of disparity between the first 

^ and aiioceeding members iu a homologous Beriea. 

H FormaJdehyde is ubiaiued by the oxidatiou of methyl alcohol. 
This ia effeL-ted by puAgJiig a raixturu of air and mptby! alcohol 
vapour over u hot spiral of platiDum or uopiK;r. The heat pro- 
duced by ihia reaction id siiflk-ifiil to raiao the temperature of the 
^iral to i«dn««a, aud to maintaiu it at this point, provided tho 

■ Btream of gas is passed over it with snfHcient voloeitv. Tho 
fonoN^dehyde produced h absurtied in water in which it is readily 
aohible. 

PFomialdohyde in g»6cou8 at onlinaiy tempemtitrea. It hag a 
very pungeut odour. Wlieu cooled with aolid carbon dioxide iind 
«(her. it liquefies, its boiling' point biriuji — 20°. iiven at thia 
tempcratiiro jinlymen7.ation begiuB, and at higher tcmperfitiire* it 
poljmeriies wilti explosive energy. When the ai^ueoiiH eohition 
ie eva{>unit«d over concentrated aiilphuric acid, only p«rt of the 
formii Idehyde la evolved as gad ; the rcat polymurtzes, mid renviins 
behind iu thu form of a white, urystulliue uuu6, colled oxif- 
mrthtfierit. The molecniar weight of tliia polymer U not known, 
bnt on heating, il is rveoMveKud into forinnldcliydL', wliieb proves 
it io be ft true polymer. Formaldehyde does not yield an aide 
hyde^umniuiila on treatment will) ammonia, but a complicalod 
t'ompouud, C',II,,N,, htjcamefhyhneamiite, a cryatalline. basic sub- 
stonoa Formaldeiiydo doea not resinify when treated with csuatio 
potaah. but is co&veried into methyl oleohol and formio acid : 



acH.o + H.o = on.on + ncooir. 




IJ« 



ORCMffIC CHEMISTRY. 



The otimt of formaldehyde a!*o r»idily undergoes polrmerixa' 
tiuu. It U tlius even that formalilehrde and its derirMtiveH dUpUy 
ft much gre«t«r tendency towards potymertxatioa thiin do tltt- other 
•IdehTdes, and differ from them in their bebaTtOQr vitb ammonia 
and vrilh L-suetic poUsh. 

An aqueous solatioo containing iOit of formalduhj-de is add 

tin(l»r the name "formalin." When di]ut«d, this \t aaed oa n 

dirinfectant, and in the preeerratioa of aiiatomicul a[>ecimen8. 

It poneasee the remarkable property of coDTerting albaminous 

fnbetances into a hard, elutic itioss, qttite insoluble in vater. 

iThe conteutA of a hen's egg, lor oxample, nudt-rgu this tranti- 

rfomuiEion when left in contact with fontialiii for hulf-an*honr: 

brain-anbstance nttaing the 00D8i>t«iiicy of india-rubber, and a 

lacion of gelatine is conrertnd into a hard, traoHparent, insoluble. 

lonrlesi maas, redacible to a fine powder, "ib drops being used 

f(>r every 500 g. of diesolvod gelatine. 

The coDc^nlnttion of A formnlln «oliitii>ti is il«lemiin«d by ikddjnf; 
excMo of a solution of sudiuDi liydrozldc of twice ibe normal strength, 
follotred by hydrojcen peroitide, wbiob eonverla the formatdehyde <«>tn- 
\ibAK\j inro fonnlc acid. Tlin araotint of alkali not lalceit jiji hy thU 
acid i* Miitnated by lilnitioa, from tlic reaull of which ttie amount of 
formaldehyde can be culvulated. since one moleoule of lli« aldehyde 
fields one molecule of the acid. 



H 



Acetaldehyde, CH,.G<y 



118. AcetaMehyde may be regarded as the typical aldehyde of 
lis eeriea. It ]io8»ee«ea the propertioe given above aa genemt for 
this ela(» of compounds. It \% obtained by the oxidation of ctliyl 
Joohol by means of potjusium hirliromate and Kulpbnric arid, and 
a liquid with n diaagrneahle odour, at least in a dilute state: 
''it boiU at 2:;'', and fiolidufieAat —11^0 (P. Aa already stated (114). 
it easily nndergoos polymerisation with formation of psiraldehyde, 
C,H„Oj. Anoilipr eonipound having the formula C,H„(>, also 
existe, called mviuldehyde; it is a crystalline product, and must 
be likewise a polj-mer, since heating reconvert* it into ordinary 
aldehyde. As in the caw of paraldohydo, it dofis not give the 
^ordinary aldehyde rtTttCtions; for example, it is not resinified by 
lis. Paraldehyde and ni(>taldehyde are pogsiblrstorooisnmers. 



KETONES. 



'39 



EETOITSS. 

projierlles of the Itetouea have been already 
moationed (110 to 112). The flrat tii«ui)>er of thtt< homolojrouo 
MrJM oannot roiilnin him thnii thn^> rnrWn atnms. 

Ejqwrieiice lias flhown that ketones, whkh may b*" repreaenteil 
<by the genera,] fcirmnla R-CO-B\ are nlu-ikVR split up ut the 
carbonvl-groii )) on oxidntion (107): Ihat is, uxidittion oiTiint ut 
tlut poiut in liiuiiiolociilv at which oxygitn isnlronily presc^iit (49). 
Tliis deoonipontion can, howerer, take place in two difTerent 
■ways: 



R.|CO.R* or R-CO|R'. 



Heihylnonylkfltone, OH,'|CO-|C^H,, , for exiunple* cbq yield 



^■fonnic acid. Oil, 0,, and caprit: acid, C\,H„0, ; or acetic acid. 

0,H,0, , and pflargonic acid. C,H„0,; ftooording us the decompoai- 

tion take splace at the points indic^to'l by tho liiiefl I and 11 

^—^respectively. The oxidation is actually Hunh that the decompoai- 

^Btion takeR plai-e at both points 8imultun(<ou>t1y, so that four acids 

■^^ ar* obtained. Two of thcittT may be identical; for example, the 

oxidation of raothyletliy I ketone. (-m,-CO«C,Hj. pruducea ucolic 

and acetic acid by dvcompudiliun at on« point of the niolvculo. 

vhile if it takc8 place ut thv other point, formic nud propionic 

ocidd ttPo proiiucod. In the majority of eaa-s, one of thew reac*- 

tiong prodoniinulCT, nwiatly that one which leaves tho cnrbonyl 

linked to tho BninlleRt iilkyl-renidnn. The oxidation nf the ki^tones 

therefore affords a means of detorminiiig tlio poaitiun wJiii'h the 

csrbony] -group occupiea in the molecule. 

The ketones are further dtstinj^iiahcd from the aldubydos by 
their behaviour towunli* limmoiiia; thi^i ha* been niirefiilly invASti- 
gated in the ciuie of anotonc, the finit momhor of the series. 
By elimination of water it yiehU complicated suhiitances, aueh 
M tUartioiitnmiuf, (',II,.N(> (3(^.11.0 + MI, - H.OJ. trinretmu- 
amin4, C.n„NO (SC.U.O + NH, - 2H.0), etc. 

The ketones do not yield polymerB, but are capable of lorming 
condeniiatioti -p rod ii c tn. 




I4» 



OHC^WC CHEMISTRY. 



Acetone, Cn,CO-CH,. 

120. Acoton© 38 prepiirod un tho manufactnring scale from 
crude WDOid-spirit (46), >md by tho dry distillutioti of pulcinm 
■cetate. It b prei>ent in rery small ({iiftiuitiex in iioriiiHl urine, but 
in mndi greater amount as a rewilt of ]>athnlngipal condilionfl, 
>H in ouea of diabelu mflliiv* und actionKria. It in a Hqtiid of 
peoiUiur, poppemaint-likc odour, boils at ^t»-3'% eolidiflM nt 
— 94-g*>, luid hae a spocifio gravity of 0-813 at 0°. It is hd excel- 
lent Rolront for mnny orgiitiir rotngiouncls, and is miaciblo in all 
proiHirtioiiB witli water. It is rnnv«rted by reduction into iso-| 
propyl iilpohol, and yieldfl a crycitalliDR oxime molting at C!>°. 

SttiphotMl, A coitipnuiid iminnaiil in medicine «a a ttoporiflo. ts; 
prepared rniiti neclone. In jiraAGnce of hjdrocliloriti ftcid, acetous 
anil«s ffitb olbylmcrcaptnii wIlli eliiniiintiou of water: 

(oa,).co + aiisCiU. =; (CH,),0(So,ii.), + h,o 

DliiiHtti UilHilivl- 
Oxidation witli potassium pemnnngnnnlo converts ihc two stdphnr alomft 
or ttiU compound i[ito SO^grnups. forming dicltiylsulphuncdiiaclhyl- 
nifithane, (C[I,j,C(SO,C,l]ili, or sulpliumtl. It ciystailiz^e in colourlesa 
prbiiiH, which diatMlvK nicb dilBcutt}' in cold water, and molt at IJW*. 

ThioiMahfdM &ad Thiolcetonea. 

HI. Thuna are onniponnds eontaining aiilphur in place of Ibe osy- 
Ecii of till! aldcliydcs and Itt-imics. 'niioaoci aldehyde Li not itself 
ktif^wo, but itii pctlymcr, trithianNialdtfiyilt, CiHttSi, is obtained bjr 
lending suIphiirLltcd bydrogou inlu aoi-Ialdcliirile in prrscuco of hydro- 
shloriti acid. Otidatiori convene it itilo n trijulphond (97), eauli sul- 
phur atom being oiidizcd lo an SOi-group, 

Although nceioiie iraoif docs nut iindurgu poljruiorizatioD, replaoe-j 
mviit of il!t oxy):rn ai.oui by a sulphur atom confera ibiH properly on It] 
111 ft liigli di*gro(>. Tilts poly men an-i ion can lie effootnd by tiie meltioda 
applied tu aldcliydttt. Tliroo molooulea l>e«oiue linked logetber, fom* 
in^ trUkioooatt>H9, i2,\l,A%. 



TIHSATTHLATXD HTTDROCARBONS. 



L ALITLEKES OB OLEFtVBS, C„Hni. 

Hfltboda of Formation. 

123. 1. The oirjine.i un; olitaini'il in the dry diiiitlUtion of 
complicaktcl car)>oii couipoiinde, which uccounts fur llieir prcHvnce 
to the cit€nt of i-i>^ in c<ial-g*s. 

'i, Ity elimination nf the elemenhi of water from the oloobo]* 

c,n„.on = c,u„ + H,o. 

Thia can sometimes he. brought atout )iy mere he&ting, as in'tha 
caw of tertiary uk-oliuk, but U is iietially iiHrw»iary to heat tha 
klcohol with a dcliydratiiig-afreDt. such am conccntTated Bulpliiiria 
ncid or zinc chloride. The oliminatinn of water from the secondary 
uA tertiary alcohols in more easily cffootod than from the cor- 
responding primary' cuiiipoundB. 

3. By splitting ofT a haloid acid from alkyl halidiw. This 
itearriod out by heating the latter with alcoholic potash, a solatioa 
of caiutic pota«h in alroliol: 

C„M,„ . ,1 + KOC,U, = C„n,» + KI + CAOH. 

Sther ia formed at the »ame timo (98): 



c,H^ . ,1 + Kocyi, = c..u„ .,oc,n, + ki. 

ftlkyi iodides are used, the reaction taitos ploco rhiefly In 
"aMOfdanc* with the first of tfiew- two oqnutJont), tho socondary 
ind tertiary indidcs lieiiig spocially gnltod for the pruduL-tion of 
nngaturntcd hydroc&rboiu. 

»4I 



ORGANIC CHEMISTRY. 



Xani*. 


Pofmula. 


IlolUtiit- 
(raint. 


Hune. 


Foraiula. 


BalHnr 

p«4lK. 


EUivtnnn. 

l*r<>pjlrnc .... 
ii-BuiyloDe,.. . 
n-AtiirtMi«.., . 
Hncjffttau 


C,H, 

C.n. 

0M.:C1I-CB, 

C'«H„ 
C,II., 


— 6* 
68* 


nvpiyleus. . . . 

No«) vIras , , , . 


c.u„ 

c,.u„ 
c,.u» 


se* 

153' 
173* 



Tlie naiiie« of tho metnlierR of thiK svn^ hfr ilerired from ttioiie 
of the saturated hydrocarbons hj- alltring the tcrtnination "mif" 
to ''yleiie." 'I'heKiR conipouude art* duuotvd l>y tbo g«Qcral diuiic 
atki/lftus or <ftt^tui. 

In order to indicato the position of the double linking in tJio 
molecnle, the nlkylenoH arci BomtitimHii rngurded u aubtititntcd 
ethylenes; tlins, CIl.-t'H : OII-CII, h culkd nyinnifiricat di- 



tMthykih^Unt, 
alkylms. 



and (CUJ,C : C'H,, oKgmnuirical dirsuihtfU 



Prop«rtiM. 

I'SS- I'hc lowAst mcmbera of this homoiogonfi Sdrics arc gasee, 
and are slightly Kolnblo in wat«r; the higher DiRmhera are Utjuids 
or solid*, iiisohible in water, but sohiblt in altxiliol and ether. At 
their mcltiug-poiut^ the specific gravilk-a of the luwor membera 
arc about 0-S3, rmng witli increase iu the numlwr of carboo 
atoms to about ^it. 

Their roost importiLnt eliemical property is tho powor of form- 
ing additiou-products, on account of which they are said to bo 
vmaturnted. Add i lion-prod uctn are very readily obtained by the 
action of the hiilogciiB, eepvcinlly bromine, on the olclines. and in 
general on substances contaiuioj: a double bond, the presenoo of 
which can be detected by their power of docolourining bromine- 
water. Another tei>t for thn pri^Renoe of a double linking, eug- 
goeted by Bartcu, in carried out by shaking tho gubetaneo with 
a dilnl« Kolution of potafutiiim permanganate and Rodinm e«rl>onatei. 
Owing to rcduc-Lion in prL^senre of ii double ciirbon bond, the violet 
colour of tbo permanganate (jnickly disappcarB, with formation of a 
brown-red , floccnknt proci]>it8te of n hydmCo of inanganei^ dioxide. 
Various claasea of eomponnd>>^ for example aldohydes, react 
similarly with pataKsium permanganiito, 6o that tho teat can only 



OLEFINSS. 



'43 



be applied, «li«n tliey are abaeot, to hydrociirltouit, uu8at4intt«d 
acids, and i\ few utia-r oubfitaiiceti. 

The haloid ncids r«act by addition with* the olelinee to fonn the 
(ilkyl h»licle8- Ilydriodic acid combines in this way vorj* rondjly. 

f'oncomTnt<><i siilpliuric acid yioldfi tho n]k_vl-fi!i!|ihnric acids by 
wJditioii, it being Koiiietimea necosrary to rmploy the fuming acid. 
The addition of sulphuric acid, like that of the haloid aci(l«, 
n-fulte in tlie union of the ocid-residue with the unsntumled 
i:ari>oo atom linked to tho smalleBt amount of hydrogen. For 

example, isobutylcuv, S.,*>C:C1I,, tioatcd with ealpburic or 

hydriodic acid yields 



CH 



'>C— CH, or 
OSO.U 



I 



This reaction may bp oxpreiuied in another way by Ktating that 
there is a tcnd«ncy on the piirt vt ttip mpthyl-groupa to iucroaso 
in camber in addition-reiictions of this kind. 

Ilypocblorous acid, ClOII, citn also form additiou<producti> 
which are chlorinatod alcoholii: 

CH, = cii, + cioii = cn,ci-cn,on. 

Stbylene GljraoietaiorbjrdrUi 

124. OlefineH can also form condensatioii-prodiicta; fur ex- 
ample, butyleuu and tin* amyltnes yit-Id them ou treatment with 
moderately dilnte sulphuric acid, although ethylene cannot be 
eimibirly condensed. 'Vhv coiideoMtion may he explained 1>7 
Basnming tliat an addition-product with sulphuric acid, an alkyl- 
mlphiiric acid, ts first formed, which then reacta with a aeoond 
molecule of the olefiue: 

CH 



j;jj'>C:CH, yields (GH,),C— CH, 



lOSO.H -f H nc : C(CH.).: 



(CHo,c-cn, 



HO=C(CH.).. 

The Eimplf^^t member of thi? wriee. CH,, mtihyUne, baa not 
beoii obUitne^l. VariouH utLttmptH have been made to pnepuro it : 



144 



ORCjtNic CHf:ujsrtiY. 



for inetunce, by the removal nf HCI from methjl cliloride: 

hsvp ulwu\'s n-siilifd in l\w fonuution. not of nn'tlijlene, tint ot' 

etbyk-uu, two ('il,-grou)i« unitiug to form a single molucule. 

Ethylene, C,H.. 

12&. Kthyletic Ih h gas, iiitil in usuullr prepared 1^ heatings 
mtiturc of alcohol mid Bitlphuric acid, KthyUulpbtiriu wid is 
first formed (60), and docomposve on further heating into ethylene 
and mlphuric acid: 

C.H.SO.H = C,H, + It,SO^ 

In the prepunition of ether tlic tempi-ruturo ii nob allowed to ritie 
above A certain limit, and fresh i^cohol n coDtinnoUy added, but 
in this reaetioji n higher tompentture is employed, and noaleoliol i« 
added. An a resiiil of thitt Rtronger hciiling, siilphiir dioxide itnd 
carbflii dioxide are produced, and are retiioTed from the ethylene 
by vaslitng it with dihite alkali. A purer prmliicrt in ohtaiiied by 
dropping ethyl alcohol on phosphorite ai-id, heated to 200', and 
Bubseiucutly raising the temperature to S30^". 

Ethylene ean nltio bo readily prepartid from ethylene hroiiiide. 
CjH^BTj. hy removal of ite two bromine ntom^ This is ePIeelvd 
by bringing it into contact with a copper-nine couple (29). 

Hthylene poRsemteft a peculiar, Bweetifih odonr, and bnnts with 
a hnniiioue ilame. It i^ slightly folnble in water and in aleotiol. 
Wbon piiSHod into bromine it ie quickly converted into ethylene 
bromide, C,H,Br,. Il is readily absorbed by ef>ucentrat4jd sulphuric 
acid at 170*^, witti foniialioii of ethyUnlphuric acid. It in a 
remarkable fact, diiieovvred by Sabatier, that a mixture of 
hytlroficn and etliylene is changed completely into ethane when 
pasfied over finely ■divided nickel, at temperaturos of leea than 'iW 
(29 iind 133). 

Amylenea, L\H„, 

126. A mixture of isomeric amyleiiee, together with peril«iif, 
U tecbnieally prepiirwl by beiitilig fusel oil (47) with zinc cblnridc. 

The isomerii? amylenes can lie Bi'paratwl by two methods, which 
are also applicable in other itimllar caaed. Due uf these \» hnsvH un 
the eoluhility of some of them in a mixture of etjual vulumea of 
wAti>r and concentrated sulphuric acid at a low tenipcmture, 



THE NATURE OF THE DOUBLE CARBON BOND. MS 

Thereby amylBulphnric acid is formed, whereas the otliers are 
insoluble. This treatment, however, converts a part of the 
amylenes into condensation-products, called diamykne and tri- 
amyleae. The other method of separation depends upon the 
different velocities with which the isomeric amylenes form addi- 
tion-products with hydriodic acid. 

The Nature of the Double Carbon Bond. 

127. In the foregoing, the presence of a double carbon bond 
in the alkylenes has been arbitrarily assumed, although the linkage 
in nnsaturated compounds can be represented in a variety of ways, 
which may be summarized as follows: 

1. Existence of divalent or trivalent carbon atoms: 

n III III 

GH — C— CH, , CH,-^'H— CH,. 

S. Existence of free bonds, for which there are two possibilities: 
a. Free bonds only on one carbon atom: 
CH.— C— CH,. 

J ; 

J. Free bonds ou different carbon atoms: 
CH,— CH— CH.. 

3. Existence of double carbon bond : 

CH.— CH=CH,. 

4. Existence of a closed chain : 

CH.— OH.. 



CH, 

It was stated in 123 that nnsaturated compounds are con< 
vertible into saturated compounds by addition of atoms or groups. 
The constitution of these addition-products, on the one hand, and 
che method of formation of the unsaturated products obtained by 
the Bplitting off of a haloid acid, etc, from the saturated com- 
ponnds, on the other, allow a decision to be arrived at between 
these four possibilities. 



I4fi 



ORGANIC CfiBMISTRY. 



It shoulil bo obeerved that tlio sdililion-produrt is the same, 

whether tlie exietene« of a rfivaleui c&rhoii aloiu, or of two fret- 

bonds on the same carbon atom, be asaunied. For example, 

II 
whether propyloDc bo enpposed to have tho constitution CH^> V • CH, 

or Cirj-C-CH,, the addition of bromine prodocei the Hinu> 

fiitlistaiice, ('II, • CBtj- CH,, Similarly, the iiBsnmption of triraient 
carbou atoms, or of free bondB ou difTert'iit carbon atomttr Icmda to 

in ni 
thoaamo rt-Biilt; thus CH,-C'1I, with two trivalent carbon atoms, 

and (.!II,-C1I,, with fi'fc- boiuk, mit^il viold iho siimv additioii- 

product with bromine. CH,Br-CU,Br. It follows that for th« 
present it is nnneceBsary to treat oft«os 1 and 3 sppiinitely. 

It is tfoay to show that addition does not takr> plaee at nnv 
cuhon atom alone of unsaturated compotindu; fur if this were 
to, cthyleuo chloride, C,II,ri, , would 'have the oootttitution 
CK,-<'lk'],, and cchvk-nt- itwlf, ('K.ril. Ethylene rhh-ride 
would tlien bu identical with th« produel obtaiuud by the action 
of phoKphorns pentaohlorido ii|kiii aldehyde, CH^-CJIO, siiioo the 
exchange of thi* otygen atom in tho hitter for two chlorine ntomrt 
yields a eompoiiml of the formula f'lI^-CIICI,. But ethylene 
chloridu in different from the ix)mpoiind r,U,Cl^ (HAiffitleHC 
thiuride) obtained fnmi aldehyde. Similarly, propylene ohloridc, 
C,Il,l'l, . obtained by the addition of chlorine to propylene, is not 
identical with the reaeiion-produrt obtitinod by treating acetone 
with phnnphonis peiitaohlriride, <.!l(j-<.'Ci,-C!I, {dtloroarpfpne}, nor 
with that from propionaldehrde, Cn,-CII,-CIICI, ( propyUdtnt 
chlorifle). Kthylene therefore eannot hare either the formula 



OH, 



i-U 



or (-'Ilj.Cll, nor propylene any of the fonuubS' 

CH,-c-cH„ cH.cir.cH, cUjtcir,, or cn,.cn,-(!n. 

N :■ 

A further inei^ht into thi; strueture of the iirisatnrnted eom- 

ponnds is dchTod from a eoneideration of the followinj; facts. 
Propylene iii obtained by the elimination of HI from M-propyl 
iodido, ('H,-('IIj-CH,I. The same compound in obtained by the 
removal tjf 111 fnim isopropyl iodide, CH,'CIlt'C'U,. lleni^e, it fol- 
lows that propylene oiunot have oithvr tho formula CI1,-C1^I,-CU, 



THE NATURE OF THE DOUBLE CMRBOfJ BOND. 



M7 



or 



I 



n 



CH.— CH, 
\ / , Mid therefore the remaioiiig posaibiHtiM are 



CH. 



in m 



cn.cii-cn., cu.ciicn,, «n.i rn.-oir : cir,. 

Igobutyime, C.H,. U similarly o1)taiu«J b}- the t!liniination of 

HI Jrom both iaobulyl iodidf, fCH,),Ci'H]CHJT| , ami Irimethyl- 

carhinol iodide, (CTIJ,Cll |-Cn,' lI|. Thns, iaobiitylpne can only 

III m 
hnve one of the formuljB (CILkC-CII,, <CrL)-C.CI!,, *iid 

I ; 
(CH,),0 : CH,. These fwo «xampteH hHow that t}te removal of 

hflhid aeid/rwH an aHt/l hnlule tukts plact in SMch a way (hat tht 

haloym atom and the hydrogen atom rrspertively split afffrom ttsc 

carboH atoms tchich arc direcihj linked to each other. 

Tho fcUoviuj; examplee will servo to further iUtigtrate this gcn- 

(■■11 
eralrul«. If III be removed from pentyl iodide, .', ,f >CU'CII,I, 

tho amylen«f C',H„, tbiui formed should, in uccordanc-c with the 

ntle, have tho vonstitutiou p ,f >('-CH,. This is in focb th« 

>.'U I I 

case, because the addition-proiUirt obtained by the actioa of 
bydriodic acid on this amylenc is not the origiual pentyl ioilide, 

hot one with tho fonnuht f>./>Cl-ClI,; this ia proved hy 

replacement of I by Oil, and conipariaoii of the tertiary alcohol 
thns obtained with that having tho aome formula prepared in 
aocordanoe with the method of iiynthesij deacrihed in 111. 

Th«coiieliUitioiiefaiuiihfr|ionty! iodide, (CHjl.CII- CI I, -(11,1, 
whifb yields CjH,j, mi fUmiuiitiou of HI. may be ttimilsrly estah- 
lifihed. This aiuylene yields irith HI auoiher peiityl iodide, 
(CII,),CH-Cni'Cn,, tho ronstitution of which is provwd by its 
conreraioii into an alcohol whjoh yields a ketone on oxidatiou, aud 
is ihi'fofore a seiwudary alcohol. 

Bcn.Kiiow has shown that tho splitting off of a haloid noid «unnot 
take place when the bslogoD atom and hydrogen atom »Tti hoc linked 
to carbon atoms in juitapoBition to one nnothor. He ntnTtt'd from 
[sobntjlene, (OHi),C ; m, , which ylul<l», by iulditton of two brominu 
atoms, (CM.)(CBr-Cn,Br. Ellniiimtlon of IIBr fn^m this dibromide 
produces (CII,)|C iCIinr, till: ■.■ciiHtihtlioii of which follows from ila 
eODTUtsloa luto a«ot(>no hy oxidnlioTt: 

(CH,),Oi:CllBr ^. (CH,),0O. 



14^ 



ORGANIC CHEMtSTRY. 



II hu not been fouml piieaible longain split ofT 11 Br- from the compoiiad 
(CH,l,C:CJIBr, ruaitobromotnUlfieiK, in whioh lliare is no liytlrogeti 
llnkwl III tho carUiti »[om tlireutly uunnecteil to lln' rHItr-i^u|>. 

128. It iR Re«n from tho torcgoinf; that only three poecdble 
coostitutiunal forinuhu rt^iimin ftir the iiU:i»LunitEHl hvilmmrboiui. 

1. Two free bundti on two cnrboii aloniK Jirei'lly liiikvil t» on(» 

another: R.Ctl.OU.R'. 
I I 

2. TriTalent carbon atoms direetly liiikojl to oue ntiother: 
CI Itl 

B-CllCIMt'. 

3. A don hip b*»nfi betwoen two carbon ntomK: ll-CH :CU.R'. 
The preferpnre is given to tho fommln with the (loiihlo bond 

for the following remioiia. In the first pWe, it would ba remark- 
able if tma b«ii(lB or trivalent wirhon atomn ronld only ort-ar in 
juxtupoftitiou to one unothor, that it;, if rarbon atoms which are 
not directly linked togethc-r could not have free bonds, or bo 
trivalcmt. .Second, cxporioiipe has shown thnt nusatnrntcd coin- 
ponndK aontnining an nuevcu number of fri*o bonds flr Lrivalent 
carbon atoms do not eJcirt. Kext to the saturated hydrocarbons 
CuH^ I ,, oomo in order of the number of their hydrogen utoni!!, 



etc. I [ydrocarltone, ('„!! 



in which one «r thT«« froo bonds, or triTalont carbon atoms, eonld 
he -iiuppoiiei] to be present, do not pxist, all uttoinpts to iBoIat« 
methyl CIl,, ethyl C'.IIj, etc., having totally failed. Thus no 
support h to he found here for the asBumption of either free bonds 
or of triralent carbon atoms. On the other haml, both facta 
admit of a ptrfeotly niitiiriLl explanation when the oxistence of a 
double linking is aasitmed, sinw in this ciwe the eliminalion of 
haloid ncid nitixt take plneo from tbo carbon atoms diroctly hnkod 
to one another, and comjiounds am-li ae C„n,n^, could not occnr. 
The antiiimpiion of the douhle bond is therefore the only one 
cnpablo ^f giving expresaion to the obeerred facts- 

The non-existence of froo hoads in the anaatorated hydro- 
carbons has led by analogy to tho conclusioTi that tliey are also 
ahscnt from other compounds ouutuining bIuuih doubly linkud, 
trebly linked, etr., eiich as nitrogen in ibt) nitrile«, uiygen in tbfl 
ketonfs. etc 

129- The assnniption of tlii^ exIgtcucD of nmUiplu bonds 
pro6«»ta at first sight, however, imrtaiu difliculti<'t( wlieu the power 



forming mMitioii-productB poascsawt by all soch Rompouiiiia is 
cousiilercil. It has been stated Bevcral times that carbon bonds 
are ouly brukon with ilil1ir>uUy (40), but in tlutt iraso tbu drkiible 
carbou bom] is very easily converteil into ii ttinglo one by formation 
of m adilitiou-proilucL It ik Htill morti romnrkabln that, when a 
fubscaoce conluiDin^ a doublv bum) In ttit imrboti rhiiiti id oxidized, 
tlie chain ehuiiM ulwavK W broken ut the position of thp double 

■ bond. A Batisfactory cxpbmation of this i^ aflordt-d by tho fact 
that in many ciiae^ in wbi^'h eubstanci?!! containing n donblo carbon 
bond are oxidized, it h posKiblc to nhow that tU& brcakiug of the 
carboj] chain at th<> paint where the double bond i» prettent, does 
Iiot ocwur dirvctly. but tbtit un addition- prodnct is first formed by 
Kthe taking np of two Oil-groups, it bt-ing ofti-n possible to isolate 
^Blliia prodnot: 






becomes 



\CHOU 



/ 



ClIOlI 



Since oxidation takes place — in accordance with the general 

rutv in 49— at a jioint where it has already begiin> it follows that 

^_iri thia caw fnrtlior oxidation mnst result in a breaking of the 

^■ctrbou clmiu at the point whore the donble bond originally existed. 

^ Thua, tlie brtjiking of Uio iinsalu rated oliaiu by oxidation dopi-udd 

^^on the fonnation of att intermedialo uddiliou-prodiiet, and it iB 

^■therefore only ni^jcaiiuiry to fiud an explanation for the ciise with 

^Kn'hich thin is t-ITerted. Tliia can be best arrircd at by a considera- 

^Bliou of the uutuiv of Ibi; bouds between the atoini<. An aflinity 

^Bor bond may hv looked upon as an attraction exercised by one 

^^ atom QpOQ another. Should an atom poaeess more than one 

^aflinity, il i* ussunied that the attraction is oxereiswl in mor« 

^■than uQo direction, aiid is coii'Oentrated at certain jwints of its 

^nurfaoe, Bomevhut after the manner in which the attraction cxer- 

^Vci9<^d by a mtignet ia concentrated at its two poles. Any other 

aa*nmpcion, ftnch aa that the attracting force if; equally difttiibuted 

over the whole surface of an atom, wuubl miike il dilBmlt to 

understand why each ek-ment shuulil have u dulurminate valency. 

If the carbon atom is ictruvulLMit, there must bo on its niirface four 

Mch points or " polce,*' situated at the uuglca of a regular telra- 

h»d rop ($3). In the case of a single bond botvooQ two such poloa 




150 ORGANIC CHEMISTRY. 

on dilferent carbou iktomi, tbeir miitaal attraction would caaso 
thuin to spprnacli one another ao cJoBcly a« jiossiltlp. 

Ba£TEB hue put forwurd the etippoeitioii thnt tbe«e polos on 
the 6urrace of CHrl:>on Atoms nro movable. Knch n movement 
rw!«Us, howpver, in a (certain " tonsion," which tends to bring 
buck the poleH to their origina.1 poHitioii. For example, when a 
singld honci between two curlioD atoms \a converted into u doable 
one, the dircctiolu of the aftinitiee of eiich of the two curbon 
Atoms inuBt undergo iiii Hpjirt-c-iitblu ulttiriition: 

Tho tension resulting from this is therefore a cuiii^ of the eane 
with which dou1>le Liouds can bu broken. We ahull ciee Intor tlutt 
Baetbr's teu9it/» Ikevry also ofTordg nii cxpItin»tion of other im- 
portuiit pheDomena (262). 

li is «««n from the foregoing that the double bond must not be 
regarded as a more doubling of tho isiugltt one, ua the exproBsion 
" double bond " would indicate. Jtt^ 



II. POLTHXTETLEHE COHPOCRDS C„nt„. 

130. Isomeric with the olefines ia a series of coniponnda. 
C„n,„, chiefly iiiBtiiigiii3he<I from the former by tlie absence of, or 
■t least a diminution in, the power of fomiiug udditiun-prodncts. 
MoBt of these componndB are very sUible; thus peutamethyleue, 
C,I1„. bears a strong re*cmhlanco to »j-pentam', ('jH„. It 
will be eeen loUtr (260-S63> thnt tho methods for the formatioD 
of thoj^ eompoiitidii net'enaitnte tho a«aumptton of A closed 
Cftrbon nhniii in the moleeiile. 

HL HTDX0CABBOII8. r„n,»_,. 

131. A variety of structureH is possible for these eomponndfi, 
which contain four hydrogen iitoms \v6s thim the corresponding 
paraffiuB. Thug, hydrocarbons containing two double bonds have 
tbo general formula C„Hj„_,, for example, 

OH,:CHCU:CII^ 



« 



MYDHOCARBOWS tVITH TRIPLE BONDS. 



»5' 



Fiirt)i«T, Btib6tanc«« coQt«ining a irip\« bond hare also tho sani« 
empiricnl compositjoD, for exnmple, 

The reaeons for the assuiuption of a triple lin k i ng in thOM 
rani[>oiiiii]g «ri> idetiliciil witli thone which led to the Aflgamption 
of the clotiblo bond iti the oUQiivg (128). 

A. HTDBOCAItHOM^ WITH TJitPLB BOSDB. 

Nomeaolature. 

132. The first memb«r, C,ll,, is ciiUecI ncelylme; the second, 
C,!I,, niftflene; th'P higher mpmberfl are generally FBganled aa 
subfa-ti tilted acetjlenes; thus C',11, ia called et/ii/laceiffle/ic, V^ll^^ 
bvtiflncelylene, etc 

Kcthoda of Formation. 

1. By the dry diBtillation of complex componnds; hence the 
occurrence of acetylene iii coal-gas. 

3. Uy the withdrawal of two molocales of haloid ftcid from 
compounds of the formula C„]Ij„X,, whoru X rt'presont* tho 
ludogen atom, thoeo compounds Uung formed by the addition of 
halogen to albyleues: 

CH,Br^OI-r Br - SHBr = CHsCU. 

KtliyleOti bruiiifUs Ai^styleDO 

Thifl IR effected by heating witii alroholic potoiih. 

A general method for tho preparation of unsaturated com- 
pounds \& (urutfibed by thia method of adding on hulugun, folluwDd 
by the removal of haloid iieid. For example, etartiiifj with 
C',Hp,.,, CjH,„,,X U obtnined by tho urtion of chlorine or 
bromine. Up-ating with alrohnlir potash nonvcrtK thiK into ('uII^q, 
from which C„II,„Rr, in obtained by the action of bn)mine, atxl is 
converted int« ("„!!,„ - , by abstmctiun of 211 Br. This cumpuiind 
cttD again form an addttiun-product with bromine, aud no on. 

3. I*y lh« abstraction of 31IX from compounda of tho formula 
C,H,nA,, formed by the action of phosphorus pentJihiUide upon 
aldehyden or ketones: 

CU.CUCl, -atlCl = CJI=t'IL 

Ethf iMcn* (lil'Tiili* An>i^l*]i« 

CH,.CCI,CH,-2nci = CII.-CaCH. 

CulcHvaui-Kiiie AllrhHM 



M4 



ORGAMC CHEMISTRY. 



I 



AMtyUne, (',11,. 

133. Acetylene i« a colourleM gaa of disagreeable odour, it 
Bomewbat soluble in vruter, and cuikdeiiswi at 18'^ and 8:t atmoa- 
pliervs to H liquid boiliug at — 83-4". It cau be 8yutli<wi2«d from 
Hi elcmunts by meius of an devtric arc botveeu carbon |m)W in 
au tttiuo8pb«TO of hydrogen, a small rjuantity of inetlinnc, and 
a trace of ethane, being eitnultaneoasly formed. Hi presence cau 
be detected by luoans of an ammoDiacal Folntion of cuprous 
ehloridi-, which yiulds a red precipitate of copper acetylene even 
whou tnires n[ ii('i>tyl(>ne are mixed with other gssEO. Acetylene 
is altfo oIit;tined as a pniduct of the inconiplelt? uombustian of macy 
oi^nie Mibstanrvs. It is prt-pared un tlie lurtpj scalu by the action 
ol waltT on ealcium mrbidt-, or ciik-ium ucetylunu, CoO,: 

CaC, -t- 2U,0 = Cft(OII), + C,H,. 

The re«ctiyn is aomuwlmt violent, and \i attended with evolution 
of considerable heat. Calcium carbide ie prepared hy heating 
curboii with <|Hicklime, CaO, in an electric furnace. The cak-ium 
liberated by the action of the carbon on the quicklime enters into 
eomfaiuatiou with the oxoess of carbon, under the iniluence of the 
high temperature, and forms calcium carbide, which is white whim 
perfectly pure, but hu» usually a dark rcddiah-brown colour, due 
to the prcaencc of Huitdl <^uantitice of iron. 

Aculj'Imio can bt* iiraiMir«>cl iil. n nioflunta cost by this melli'Ml, nml 
atlempta linrc l>o«a iiiadc to use it far lighting pnrposa. aa a stream 
of tbo gaa, poitBL'tt ibroBgh a fln« opetiitig, bums witt an iatftniu^ty 
lutninoiin fliiini!. Tptotlie |>re»eut, rliviieAlteiiipCfthavebeeii ■Itcndrtl 
by illl1l<nilili»(, piirtly onlnff to the cost of praduclion. but mnre in lite 
nature of nccljlcnu llsclf. It tomiB csplotslw copper ncL-lylt-Do with 
tbe cop|H>r of tbo ga»-fi<tiiigs: a iniilur(> with air explodes with 
extrome Tiolaacc. and is niiich mora dangproua than a mixture of 
ordinary coal-gas and air. TbU is due to th« fact that aiucb lioiit 
ia Inkeu up in the formalioiiufacotylcnv, ihiscomponDdbvin^itlronKlj 
en do the nil tn (" Inortfiitiic ('licmistry," STj. In nclditiou to Ihjs. ihc 
liiaile of i-xplnsiou arc much wider than for any othc'r gas. nn i^xplo- 
aivD mixtiiru being formed with air by the admixture of 3'8?f of 
acetylene, whila in tbo ca*« of Goal-Kafi tbe lioiiu arc ouly &-3df. 
The Teloeitjr of propa^tion of coiobastlon Is also mueli greater in the 
case of aoetyleno, and this uugmeufat oouidvrabty tbe foreo of the 
«xpto8lon. 



HYDROCARBONS IVITH TWO DOVBUt BONDS. I55 

Acelvleiie prepared frutii CitlciUtn carbid« soiiMlini«s conUiiiH 
kll qunntiltsA nf kulptmroltcxl hydrogen and pbospborotted bj'dro- 
g«ii, i» wliioh ilnwea ils ditajtreeobk' 6dicI). It uiiii be frt^ed from Ibe 
fonnur b> a. aoliitiori i»f ciiuaiic »lkNll. aud from tbo lattur \)j a »«4n> 
tion of corroetre £ublituat« In hydrochloric Mid Thu rcmorul of 
plio«plioretb>d hydrogen :s of special importsncf, »iiic« ils prcseDCo 
nuiy Iwkd \o t)i« Kix^ntancons ii;nitioa iif the gns. 

By Ihv diffi't tiydroKenntion of acetylniB Id presence of Fnlciced 
njckol (Wiiiid lU). Sasitieh nnd Skm>brkks ba.ve obtained liquid mix* 
lURS of hydroc:irboiiK wliicli can Ijc [tiitiln lo corrf^jHiiid either with 
American or C«ucaaijin pftroloiim by varying lhi» iwnditionii of ths 
experimenl. To account fortbe formaliou of petrolotim. ihcy lunumc 
that thero arc in lh« interior of (be oarth froe nllcnli-mptKls and 
mtlallic carbides, which in coniact wlUi water give riao lo tnixiurcs of 
hydrogen Ami h]rdn>carl>on.>«. Tb«ae gaaes encounter finely -divided 
nickel, cobalt, or iron. aii<I tlnus ykld the niixturva of hydrooarbona 
coDgtiiutitig natunil pulrol«um (H). 

IL HYUIIOI'AKBONS WITH TWO DODBI.K BONDS. 

134. nydn>cjirbon» with two double bonds tiavo been compan- 
tlroly liltio Invntti^tod. AiUue \* obtninixl from tTibromopropano, 
CIIfBr-CflBr-CiliBr. by rauoval of lIBr by nipans of potaali, and 
BuhsM^uenl tre.ilment of the dibrotno-componnd thus f<irmr<(l with 
tine-dust, which removes tho two romaining bromine atoms (IM) : 

Ca,Br-CHBr-CH,Bf-»CH,:CBrCU,Br —■ CH,:C:CH,. 
TnbrDmapropaiie WbromopropyleDo Allnia 

Its oonatitntion follows from ttiis motbod of preparation. It is a 
colourlna gaa, nnd unilka the inomeric altyleae, OHi ■ CeClI. does not 
yk-IJ KKtalliodorivativeB {188). 

IHitlltjl. OH,:CII.t'H,.C:H,-OII:C;Ht. Ih obtained by the rcUob 
of AOdiiitu npon allyl tWi</(, CEIi.CII-CIIiI \\ti\, from which It 
ftdlavrsibat tl tius thu cuiitdiluiion indtcnu^-d by ibr above foruiula. 

A hydrocarbon of this scries of theoretlcat importanco U i»oprw9, 
C*1I*. It b obtained by tbi; dry distillatioii of caoutchouo. nnd is a 
li(|uid boiling at 'il'. By llio union of two or moro mo1conle&. It 
pussM into terpeiipj*. C>«H„, CnH,., elv. tt Ib convened by <!on. 
««iilrat«d hydrochloric ncLd into a cubscanoe strongly rwtumbiing 
caotitobouo, perli.-ipa identical with iL Isoprone is provijd lo haw iha 

eoostiluiion ^[J'^C CU=CH,. by ibo addition of SUBr, whloU 
leldsAdlliroinida. ^g'>CBr~CII,— CD.Br, identical with that ob- 
tained from ditnetbyUilleiic, ^^[>0=O=0H* 



J^ 



miMtlTttttOll PKODVOTfl OF TBI UVSATTOATBD 
KYOROOAIIBOirS. 



«■.** V .K\«*-V i* Vn-'N'VwA-MWit^V^ Wn-« :a*B, tan :aaCMSiaasa! 



■*N.- .- -•, •-— . . -...7 - -V •. f .;. •-■ . aftM&.-.^n: 






UHSATURATEO H/*LOGEN COMPOUNDS. 



«5: 



i 



methodf) by which thciic compoimils an? obtninetl indicai« 
that the halogen ntoni in thc-tn w linked to s mrbon atom buvitig 
a double bond. Thi^ir iinipcrties differ widuly from those of coin- 
poiiiidii, Kurh ns tho tilkyi hiilidc^, in wluoh thu hulogon Atom it 
hnked to a carbon utom having nnly ^nglo bonds; and thia nilc ie 
generally nppli«ible to oniripoiimisi of thia kind. Tho halogen 
atom of the nlkyl hnlideK is ejip4M-ial)y siitited for taking part in 
doable decompositions, htning rBphiceahle by hyilrnxy], »n alkoxyl- 
gronp, an acid -residue, thp iimido-groiip. etc. 

This apfiitide for tloHbh (lecotHpotitinii is ahiwt n'holli/ wanting 
in compounds tckoi't halugm atom is linked to a carbon alom with a 
rtoubie boml. Alkalis do not <*onv<'rt thpm into alcohols, nor 
ulkoxidee into ethere: hnt inrariably, whon a reaction doce tiiko 
p1ac«, a haloid acid ift uplit off, with formation of hydromrhong 
of the eeries C,.U,„ ,. 

An ifiomer of a- and fi-chhropropylef^e, which have been 
referred to above, id called aflyl chloride. The halogen atom in 
tliia L-om[iuiind tiiki*^ purl, in double dooonL|)oaiiiuiid as eosily as 
tliat in au alkyl eliloride. Allyl eltloride is obtained by the action 
cf phosphoms ]>enCachIonde upon allyl alcohol, which can be 
Hrepared by B method to be drsrribpd Inter (168). This alcohol 
yields M-propyl alcohol by addition of hydrogen, and its hydroxyl- 
jgroap must therefore bo at tho end of the carbon chain. Henoo, 
th« halogen atom in allyl rhloridw mn«t aUo be attacihod to 
Llw end of tho ohaiii, titico it takes the placu of the hydruxyl- 
^Toup. Given tho constitutions of a- and /^-[iropylvno chloride, 
which are dedtiwd from that of propionaldohyde and acetone, the 
»Ilyl hnlidea c*n only luivo the i-onBtilntinnal formula 

Jleru the hihlogcn atom isnttHohed ton Kiiigly-linki'xl r-arhon atom, 
aud retaiiiit its uormal character in spite of tlie proaunoe of a 
doubh- txind in tho moW-ulo. 

This dependence of the charneteT of a halngon atom on its 

iHMtitiou in the molecule of an uumtunited nomponml affonls a 

kuieana nf determining wlielhcr it is attai:hed In n cingly-l inked or 

dotibly -linked carbon alum, by a«certuining whether it does or 

doci not po«eo« the power to take part in double dceompositioDs. 

Tho following are examples of individual members of tho serin 



fiUBSTrnrTIOH-PBOBUCTS OF THE UHflATTTHATED 
B7DB0 CARBONS. 



V 



"^ t ima&TiraATES halooev coiiMinrDB. 

130. SInre Ch« sHtnmttHl hyclmnftrliong thomsielTes ilo not 
poKM^ any mlient charactPriRtirn, the properties of thvir com- 
poandH (lttp«ni1 upon the nature of the snbfitituttng Bl«tnents or] 
groupn. Hitherto we h»Ye otilv rotieiderctl rotnpotinda whosej 
properties are iluc to the presenre in the molecule of u single 
group, hydroxyl, curboicvl, a multiple carbon bond, etc Wo have 
now to deecribeBubBtaticofl containing more thnn one eharaetcrigiic 
group ill the molecule. 

^\'hen thees groups nre present simultaneously in the samdi 
Dioleeiilo, they generally exerriso a niodifring influence upon one 
another. The extent of this inflnenre rarica considerably, aa will 
be seen from a consideration of the different cJaesea of nneatniat«<I 
halogen compounds. 

Halogen derivatives of the type C,H^^jX are obtained by the 
addition of halogen to the hydrocarbonB C„H^, and iabBequont- 
abetraction of one molectile of haloid acid ; 

CH,=Cn, + Br, = CH.B^-Cn.Br. 
CH,»r— CH.Br - llUr = CH,=CHBr. 

KiIii1pii<i hioiiifilr Yliijrl liNititlilR 

They are also formed liy removal of one molewtle of haloid acid 
from compounds i:ontaining two halogen atoms linked to tlie sume 
carbon atom : 



OHj.cn.cHci, - nc] = ch,-ch=chcl 

CH,-CC1,-CH, - nCl = CH =CC1— CH, 

ChloroAertooe ff-OMorvpravTl«n« 



tS6 



1 



VNSATURMTED HMOGl 



I 
I 



Tho methodR by which Ihpse compoimilx arc ohtiiiiie*! itidicnte 
that the lialogen atom in them in linkoil to a uirhon utom huviog 
a iloable bond. Their prnperticji differ widwiy from those of com- 
poiinds, such ae the ulkyt huHileB, in which tliu halogen atom is 
linkod to a carbou iitom having only single bond*; and tiiis rule ifl 
genenlly applieablo to eompoiini]? of this kind. Tho hnlogen 
ntom of tho alkyi hiUides is OKpooially snitpii for t»king jwirt in 
double docum position 8, being Tephiceahle by hvilroryl, an alkoxyl- 
gTOiii>, an acid-residne, the amido-gronp, etc. 

This apiifitde for double dec<impo»itinn is nlmoitt wfiollij wanting 

in c&mpOHHdi whoKe haiogen atom is UnXxd to a carbon atom with a 

I d<fHblo i^ttd. Alknlie do not ennvart thorn into alcohols^ nor 

alkoxid«£ into others; hut invRrinbly, when » reaction does take 

|])lace, a b^loid acid is split off, vith formation of hydrocarbons 
of tho aerUas C'„Hp,_,. 
An UoRier of «- and ff-chlDiopropyhnfi, which have beon 
roforred to above, ia t-allod aUyl (khridt. The halogen atom in 
tluH compound taked part in double decompositionu m easily us 
t)iac in an alkyl ehloridt>. Allyl ehloridu is obtiijnud by the notion 
^^ of pbuHpborus penUiehioride upon allyl alcohol, wbieb can be 
^B prepare*! by B method to be deecrihed later (158). This alcohol 
^^ }-ielrU M-propyl ali^fth"! by addition of hydrogen, and ifcfl hydroxjl- 
^^ group must therefore fee at the end of tho carbou chain. Uence, 
^H tbo halogen atom in allyl L*hlorido must also b« attatibed to 
^^ the oml of ibe ubain, siutw it takejt tho place of the Iiydroxyl- 
group. (iiveu the roiistLlutioiiK of tr- and /)-propyleiio clilorido, 
which are deduced from tliat of propioualdeliyde and acetone, the 
ftllyl halides can only have tho ronatitiitional formula 



I 



CH,=CH.CH,X. 



IFerr the halogen atom iri attaohod to a singly-] inked carbon atom, 
^^ and rL-tuiii« its normal characber in spito of the pn;t»m:e of a 
^■double bond in tho molecule. 

^H 'V\\m depcn<li!m'u of the character of a hnlngen atom on its 

^K pcmttion in the molecule of an iiuKatiirtitec] compnnnil affords n 

' nieanii of determining whotbcr it U Httaehwl to a aingly-linked or 

doubly-linked eorbun atom, by lucerLaiuing wbethor it dne« or 

doM not iMMM«s the pi^wer to take purt in donblv decompoaitioos. 

The following are oxamploii of indi%'i(hinl members of tho sorice 




OfiGylWC CHF.MfSTKY. 

Vinyl chloride CII,: CHOI is n gM, vinyl brmidt CH,; CHBr ti 
liquid of ethereal odonr, Iktth these oompoiiiiilH polToierize 
readily. 

Alhjl chlori<le, alli/J brotuide, and alhjl iotiidf, boil reapw^tiTclT 
at HV, 70", and 103". Tlu-y nre often itaod in »>utln*«i for tbc 
iutroduction of tin uusatunitcd group iiito u compound. The; 
Hato a charactoriAio odour re^mhling that of iniirtArd. 

The propart/yl eompeunds, CIt=C'-CH,X, may hn moiitioned 
as a tT()o nf the BcriPB C„II,„ .,X. Their coniititiition is inferred 
from the fact that they yield motallln derivatlvos, showing thut 
they contain the group 0=11, ami also becauHe their halogun 
afcom is capable of taking part in doiiUo documpoaitioiie, und la 
therefore attached to a Biugly-liuked carbou atom. They iiro 
obtained from propargyl alcohol (138) by the action of phospbonu 
pentahalido, ami are liiinide pnesemTi^ a pungent smnll. 

Th« comjintiiid CI1Br;C. bromoactlj/lidetie, which is nnaiDcil bj 
Kep tu cunljiiu a divHlviit curbi>n ntoin, um boobuiiimd trvm NceLyteu 
bromide, C'llBr: ClIBi-, by dvAtmcnt mlli nicoliulic palAeli. It is ■ 
gas, taking Are sj>oQlanQauBl}r in tbe air: iu Holutioa in xloobo) ia 
pli«epl»>r««ceDt, oiriDK lo slow oxidation, and ttio gas itMlf has an 
odour very similar to that of phosphorus. 



U. PHBATOSATED ALCOHOLS. 



136. The hydmxyl-gronp of the unaaturated alcohols may be 
attached to a oingly-linltod or doubly-linlied carbon atom: 



cH,:cn.(;ii,on, 



CH,:CH.OH. 



Very few compotinds of the typo of vinyl alcohol are bitown. In 
the inajurity of cai-c* in which their formatioE might bu expected. 
their isomore arc obtaiDcd. Thus, when water is abstracted from 
^yool, CH,OII ■ CH.OH, there results, not vinyl alwhot, OUOH, 

CII, II 

but Ml iaomer, acetoldehydp, | 14 _ ^H, 






When /if-broniopTopyleno, CH,-CBr:CII,, is heated with 
water, there is formed not /S-hydroTyjiropylene, CH,-C(OH):CIl,, 
bnt the isomeric acetone, crt.-CO'CIt,. It hiw been geDenUly 
obHerTed that in raaex in wbieh a grouping of the atoms lu the 



ORGANIC aiEMlSTRY, 

Allyl alcohol maet therefore contain the group — OH,OH, which 
U chanicteristio of primary ak'-oliuU. 

AII7I alcohol is a liciiiid with itii irriuttiiiK odour, soHtlifyiD^ at. 
— 50^, and boiliiifc at ^la-o", and ih uiiacililu with water iu all 
proportions. Its apccilic jjraritT at is DiS^a. It forms siidi- 
tiou-producl9 with th« Imlogens and witU^drogeu, yivldiug with 
the lattvr n-propyl aloohal. 

Many other coiuiKiirnds containing thonIlyl-gn>i^CIIi:CU-CII)— , 
are known. Of itieeo all^t tulphhie (CM,: CH-CHT)*S, X\w principal 
con&tllii«iit of oil of ifarlic, imiy >>« nii^iituiiiMl. It 'u, flvuilietically 
obtained by the aclion of poUusiiini Huiiihide, K|S. on allyl iodide. 

We have seen that tho influenoe uF the double baud iii the 
tineaturuttid halogen oompounds und uluufaols ia very proDonnced 
when it is eiLuutcd iu the itnmmliuti- Ufijjhhourhood of halugvu or 
hydroxyl, but that otlicrwisc it in muuh less marked. The nile Is 
that when ttev groups are titmittd in immtxtiale jrrorimUif to OM 
anothfT in the s^me molftcnU, earh group eJt^rdtfet a slrong injtufnes 
tipOH the properties: of the other. 

Propargyl Alcohol, CH=UOU,OH. 

ISI. Profxirijyl ateotitl conlaioa a triple boud, and ia pr^-pxrod in 
the follrtwlne wny. CnvBrCflBr Cri.llr. Iribromhjdrin \\ii). ia 
oonfertod by treatment with caustio potash into CHi !CBr-CHiBr 
Wheri ireHttxJ with potAtMiniu ;icvUtu and Itiuii «i[ioiiifl^, ihU vtdda 
CII. :0Br-C>l|01I, tin<!» only tho torminnl Itr-ntoin 1« capaMe of 
taking pure in u doubU' dniomposilioii (ISS). Whvu thJa alcohol in 
ngain brought into conlact with cjkuiitic i>oiiuli. HUr te »plft off, with 
formation of proparj;yl alcohol, llio con^titiiiion of which is indicainl 
by this motbfld of rornDition, nnd nUoby its pro|iortici. Tlie presence 
of t)i« Krutip ■CII ia shown hy tliu rorniutiuii of metallic dniTativos, 
and Liuic it is a [>nniary alcolml i» pruv-*^ Uy the fnet Uial on oxida- 
tion il yields i^ropio/ic add^ CllsC'COOII. iiii acid containing tho 
sani(> ntitnber of tarboii atoms. 

Pr^)pn^g;l alcohol ia a UiiLiid of aijreeable odour, aoluble in initsr, 
auci btiilinp at I14'-n3' ; iu speciflo frnirity at 31' is 0-H8. lU 
m«t«liig dcriTAtives are expkeiTe. 




KOHOBABIG inrSATTTRATSD ACIDS. 



L ACIDB OF THE OLEIC 8EEIES, CdH.b _ ,0,. 

139. The acida of the oleic Beries may be obtained from the 
Batnrated acids C„H^O, by the general methods for converting 
saturated into unsaturated compounds. 

1. Substitution of one hydrogen atom in the alkyl-group of a 
saturated acid by a halogen atom, and subsequent abstraction of 
haloid acid by heating with alcoholic potash. 

2. Removal of the elements of water from the monohydroxy- 
acids: 

CH,.CHOH.CH,COOH - H.0 = CH,CH:CH.COOH. 

^HydrozjT butyric add Crotoiilc acid 

The acids of this series can also be prepared from unsaturated 
compounds by 
*^. Oxidation of the unsaturated alcohols and aldehydes. 

4. The action of potassium cyanide on unsaturated halogen 
compounds, such as allyl iodide, and hydrolysis of the resulting 
nitrile. 



VomenolatUTe. 

140. The majority of the acids of the oleic series are named 
after the substances from which they were first obtained, but a few 
of the middle members have names indicating the number of 
carbon atoms in the molecule. The first member, CH, : CH • COOH, 
is called acrylic acid; others are C,n,0, crolonic acid, CgH,0, 
angelic and tiglic acidsy C„H„0, undecyUmc acid, C„H„0, oleic 
acid, C^H„0, erudc add, etc. 

i6i 



15* ORGANIC CHEMSSTRY. 

It miglit tm &ntici|>a(«d thKt in tbi» case ttui splfttlDg off or luUold 
Acid itlso takes place oa indicnled in tbo Becond raetliod, with tbe pfo- 
duolioa of two double boiiila -. 



«r 



CH..0C1,.CH, - SHCl = CH,=C=CH,, 



Cn.CHBrCnBr.OU, - SHBr = CII.=CHCH=On.. 



EiperiencQ has nhown iIikI this I'a not the case. The formuln of tbe 
r«inltiii(; prului^i mny be deierminod, for example, bf a study of ita 
tiroiDini: nJdiuon-products, and idw ffom Lho refictioas chiir&ctcmlic 
of ootnpoundB contaioin^ the groap sCH (sec below). 

Some of the livdrtinarboiis [irepared by the foregoing methods 
exhibit a jiecuHur WImviour towurdx an nniiuoiiiftpal eolation of 
eiiproiia chl«rtd(i or of » silver ealL, which aflordst u ready means of 
rocogniziDg them. Bj replacement of hydrogen, thej yield 
m^taUii!: (lerivativpR, inaiiluhle in th«> nmmonia^al Rolution ur in 
wut^r, whii^h M-jMinite out && a vnlnminouB pretMpitHte. Thfoe 
compDund.s unt explonive, the copper yellow or red, and the ulvvr 
white. Acctylcnt yioids tlieao tnetiiJIic compoundii, and of ibi 
bighvr hoinulogttiM, tliosu di^rivt^d from the dihslogcii oomponnds 
of the Aldehydes nUo give thorn. Their method of formAtlon 
thows that Ihene homolojfuon contniii the groap sCH: 

C.H^,,-CH,0HO — C«U^^».C'U,t;H{;i, — O.H,. , .cscn. 

From this it may hn concludeil that th« group ^CII ntutt Ao 
fmrnt in the hifdrontrhonn wkif-h yield metailii' dttrtvativtt; it ia 
the hyilrogen of thU group which in replmted by metala. In 
support of this \iow ie the fact that only the dichloru-deriratiTes 
of the rnvthylketonoa (110) Oiin b« trtuiafonncd into hydrocarbonaJ 
yielding metallic compoiinde: 

C»H^,,U0.CU,~^C\U.„,,CC1..CH,"CH,,.,.0=CU: 

C,H,.CO-C,H, — C,0^.CC1,.CH,.CH, — CV1,C'=CCU.. 

Da«4 nac jitM iiMtaiUe 
■IrriTiUrm. 

The isomeric hydrooarh^ns containinif two donblo bonds (134) 
are also incapable of fomiing metallic pumponnda. 

The hydrucarbouB are readily prepared in tbo free stale from 
their matiJUo derivatives by tht- lurtion of dilute bydrocliloric sicid.^ 
Thi> affords a mvaus of isohitiu^ the momben of the acrii 



HYDROCARBONS tVtTH TRlPie BONm. 



•53 



• O^Hy,.,, which yield sucli dorivativeii, frum luixtureH, and of 
nblftining them in ttK> puro state. 

The hydntcarboiis of this eerioe can add on four liulogon atoma 
or two molecule)! of a haloid acid. In prcMD«o of mercury salUQ 
they can take up water, fonaing iildohTdos or ketones: 

CH=CH + H,0 = cn,.CHO. 

OH,-C=CII H- II.O = cn.oo.cH,. 

Id this reaction, mercury ccmpounds are first formed by addi- 
tion: thus, wheu nlljlono, C^H^, \» paseed into a solution of 
mercuric chloride, IlgClj, & prt?cipitate of the compoeitiou 
3HgC],3HgO-:2C,H, is first formed, and is coorerted into acetone 
by the action of hydrochloric acid. 

The hydrocarbona of the acetylene series also posMSS the power 
' fft yielding condeneation-prodnctt;. Thin eometimes takes place 
between three molecules; thus, acetylene, C,H,, eondensea 
Wnseue, f'|,H„; dimetliylacetyleny, C,Hj. to liexamethylheuzetie, 
(',,11^. etc. The action of heat on acetylene, and of sulphuric 
acid on ita homologuce. effects this transformation. 

A remarkable reaction, resulting iu a change in tlie [xiaition ol 

I the triple bond, takes place when the hydrocarbons of the serieaH 
C,H^^, containing llio group sCH arc lioatod to a high tempera- 



C,nj-C-H,.C=CH is converted into C,n^-C=C.Cir,. 



I'mp] IkCMf loDO 



Klliylms thylftpBrjItni* 



It is probable that in thia reaction uii addition- product h fir 
formed at one part of the molecule, followed by a splitting off from 

•unnther part. Thitt tho diaplucement of the triple linking doo8 
take ptaee in thn exaiuph* givfti abuTe, is proved by the fact that 
mlthongh pmpylscetylene yiolds metallic deriratirea, the xubctance 
^■obtuiuud by hiatiiig it with alcoholic potoah does not, but is mn- 
^^-wtivd by uxiduliuii iutu jirupionic .%ud acetic acida Thi« dctcr- 
minca the position of the triple boud, since, for rcuaons aimilor to 

ItIiiMe which apply tfi thu dotiUle bond (139), the inrlHUi chain is 
fanikcn by oxidiiiitm iit the ptiiiit nrcupiod by thu multiple hnnd. 
^bo sabstance obtained must therefore have the fonnula girea 
above, and hu othylmethyUcutylcno. 



»54 



ORGANIC CHEMISTRY. 



Acetylene, i\Ry 

133. Acetylene u a ixdnurlvM gua of disAgraoftbb odour, U 
Bomowhnt itolnbic in WAter, and condcnics at 18° and 83 atmos* 
ph<>n*H to a li((ttit] bniUiig at — 82>4". It nm he syiitheinized Trom 
itii elementa l>y meniiii of im electric; atc, i)(>tu'iM>n riirbon jmles in 
an iLtnioiiph«re of hydrogen, a »maiXi quantity of metliHne, and 
a traco of ethane, bping eimultancou&ly formed. Ite prcsenre cno 
be dpt(!ctcd by tnctuna of iin ammoniucul eolDtion of cuprous 
chloridts which yields a red prtjcipitatc of copper acetylene even 
wlifii tnipos of Bcotyl*?no «ro mixed with other gases. vVet'tylono 
is iiIbo obtained as a product of the incomplete coitibii»tinn of ttiauy 
orgatiir fliihuUnreB. It is prepared on the large gcale bj the action 
of water on calriiim rarbide, or calrium aretylene, CaC,: 

CaC, 4- 2n,0 ^ CalOIl), + (!,n,. 

The reaction Jb somewhat violent, and is attended with evolnlion 
of coiisidtTable liwil. Cahnum carbide is prepared by heating 
citrhoii witli tjuieklimf, CaO, in au vIcuLrie furuaoe. The caleium 
liberated by the action of the earbon on the qnieklimo enters into 
combination with the exeejw of carbon, under the inflncnce of the 
hiph tempemture, and formn euleium narbide, which is white when 
perfectly pure, but haft UKuallr a dark reddish-brown colour, due 
to the prcHcneo of small quantities of iron. 

Acetylene oan ho prepnrrcl iit » inodemtG out by tliui meihod, and 
Aliem|its have been miwli; u> uao it Tor liglitin^ piiriinscs, asn stream 
of ih« g(U(, pn»ii<ii (broiigli n fine o|wnirig, liiirtiswirh nn liiionsely 
luniincti.t flitmc. Tp to the present, thc^icatlcmpishaii'cbt.-cn nttendrd 
by ililli'Ciillii^, jtartly owitif* (o ihe eoHl of production, bill more in tlic 
nature of nccijlciie ilaolf. U forn» explosive copper aceiylene vritti 
tbu coppi-r of tho )i;ft.i-11tllii)tH; a mixture nitb air exploilra with 
extreme violence, xiid lit inutb mora dangerous than a mixtura of 
ordinary cualgiis iind air. T)it« is due lo Die Tiiet thai miieli )ieat 
ia taken ui}in tin? forn]»Lmnofncet]rli:nc. tiiiscooipuaud buing&tronfly 
enduthcrmic (" Inorganic ChemiBtry," 97;. In adtlition lo Oiis, the 
limiiH or explosion are much wider lb.in fir any other gM. an pxpio- 
■ire miituro teing rormed with nir by iho admixture of S-82f of 
acelyletie, while iu tbe ca«c of ooul-f(iM tbc liniiU are only S-ftSX. 
Tbe TetocKy of prupagution or combustion is able much greater in the 
case of aootylooe, aud thie augncnts ooasidcrably lb« fococ of the 
explosion. 



HYDROCARBONS WITH TtVO DOUBLE BONDS. IS5 

Acptylenc preparutl from ciilciuiu carbide nan)i>limefl contains 
small qiiaiiiilies of 8ulphiiret[c<l hydrogen aud phoaphnrellcd hTclro- 
gen, to wliich it owed its disagreoivblc amell. iLcnn bo Tmud from tlin 
fonner l>j a ooliitiuii of cnuKllu nikiili, and from t\w liitk-r by » siAu- 
lioa of corrosivfl siitilinintu tu hyilrocliloric ncii) Tlic removal of 
pfaoopborettcd hydrogen is of upecial iiii]ioi-lniic«, siuoo iia preseooe 
Dfty Iflnd lo the BponiBOe^ua igiiitiou of llie gaa. 

By tlio dim^t hydrof;euHlioti of acHttyleric in presence of Pndiicwil 
nlcknl <BS mid ISi), Sibaticr itnd Scvderkit!: havoobtniiied liquid iiiln- 
lun» uf hydixwiirbi}[is which cna Iw luitdv lo corrwpund ddicr vritb 
Ann'riuiii ur CtiicHdiiiii put I'lli.'um by varying thv noiidtiiciiiii of the 
eiperimani. To account for the formotian of pclrolpum. Ilioy aAsiimo 
tlial there are in the interior of the earth free alhali-moialit and 
mMnllio onrhide-t, which in cnulaot with naier leive riftw t« oiistuntt of 
hydrogen And hydrocarbons. Thi!s» gnsot encoiinler flnoly-dlvMwl 
nickel, cubftlt. or iron, and thiin yield Ih^i mixturt* of hydrocnrboDa 
constJIutind: nntund ]>utroI«iini (Ml, 

B. IITDROI.'ARBOXS WITH TWO IiOtlHI.K »OXI>.S. 

lU. HydrocnrbouB with Ivro diinble bonds huve been comparn* 
lively Ittila inrMii^^AU'd. Attmr. ix oblniried fmm iTibromopropane, 
CniBr-CHBrC'lIiUr, by mmoviil of IIBr by mcAnn of pocafih, and 
substiqiieiit tivnlmmit of Iho dibfoin(>-cum]Kiiiud thuH Formed mtb 
zioo-dLiat, which remorcs the two remaJntiig bromine aloniA (IM) : 

CU.Br-CHBr.CH.Br-* OH.iCBrC'H.Br -• CH,:C:On^ 
ThbruriiuproiMiiie [iHiramupropjleaB A-ltana 

Apmttttition fotlowA from t4)is methml of propnration. It is a 
fl l oari— gaB. Hnd nnlihothe iaomoric allyleno, CncCsCII, drwn not 
yield m«billiodoriVHtiv0B (132). 

DiaHyl. CH,:rH-('n,-Cn,.Cn:rn,, i* obtained by th(! ncium 
of sodium uiwn a%; ^ffije, cn,;CH-Cn,I (lU), from whieh It 
follows that it hus thu couatilution iodlcjitnl by ihc above formula. 

A hydroc'arlHiii of ihU Kuriasuf thooruiiuil im[)i>rtaiiao id ittoprettit, 
Ctlli. It is obtiiined by the dry distillation of caoutchour'. ;iiid ts k 
liquid boiling at .17'. By the union of two or more mnlcciiliM. It 
pastes iciio lerpeiieH, CuIIit. CnH,,, ate It is coiivcrted by cou- 
«niiTiilw1 bydrochlurie ncld into a. gnUstwico Klroni^Iy rwembiing 
oftoatchouc, pcrhnps idunticnl irilb it. I«opr(-iiG is pron-d to hnve ibo 

eonstittition p|j*>-C.OH=Cn,. by the addition of 9HBr, whieh 
yielda a dibromide. ^g| > CBr— CTI,— CH.Br. idenUc»l with (hat ob- 
taltwd from dimelhytallene. pJJ' > C=C=CH,. j^ 



STTBSTITUTIOH-PKODUCTS OF THI TTHSATTIIIATED 
HTDEOCAEBOHS. 



i^ 



' I. tTHBATtTKATZD HALOOEW COWOinrM. 

1S5. Since the satmmtcd hydrocarbons thomBclvcs do not 
posscM any wHent clmnuitertstirR, thu propprtiM of tfactr com- 
ponndn i1<>{ir>ni] upon the luituro of tho Rubstitiiting elements or 
groiipR. TTithprto we have tmly <'onHiderp»l ntunpoiinds whnee 
properties are dtio to the pivBitiHTc In tho raoIecniR of b fiinsle 
group, hrdroxyl, curboxyl, u multiple furhoii bnwl, etc. We liave 
now to deflcribo subetanoofi containing more than one cKAnict«ri«iio 
gronp in thd molomlp. 

When thpBo groups are proiioiit Kimultaneonely in tho same 
molecule, thej genemllj' exemRe a mndifying influence upon one 
another. The extent of this influence va-rios ponHidemhly, lu will 
be neen from a (ronHiduralion of thu different i-lusses of niisaturut«tl 
halogen compounds. 

Halogen derivatiVM of tho typo C„lI,n_,X aro obt&inod by the 
luldicion of h&logon to the hjdroearhonB C.H,^, and snbsequont- 
ftbBtraction of one moleoiile of haloid acid: 



CH,=Cn, -1- Br, = CH,Bi^CH,Br. 
C'I(,Br— CII.Br - HUr = CH,=CIIBr. 

F.lhyliinn liroriilili* Vlnjl lirnmli* 

They ore also formed by removal of one moleciilf of haloid aci4 
from eompounda containing two tmlogen utums liukeil to Uia eune 
carbon atom : 



CH,.Cn,-CHC], - HCl s= cn,.rH=cuoL 

TiopylidKia chloride ■'Oiloroi'ropr'i^n* 

C^.0C1,.CII, - HCl = cir^cci— CH^ 

CnlorowtflnnR 0<C»U>rapmiirlFne 



196 



UNSATURATED HALOGEN COMPOUNDS. 



>$7 






'he methoiU hy which these compontuls arc obtjiined indicftte 
that the halogen atom in thorn in Ihtkod to » nirbon iitom hurtng 

\% donhle l>on<1. Their propertios differ widuly from those oC com- 
potinda, atich ae tho alkyl halidos, in which th« hulogon atom is 
linked to u curb'Ou utoin hnving only single bonds; and tliix rule ii 

hgeuerally ap]>li«nble to conipoands of this kind. Tho halogpn 
atom of the alky] hali(l>e« is «Rpemlly united for inking part in 
dotiblo decompositions, being nipliirpabl e by hyilroxyl, an ulkoxyl- 
group, nn ocid-rosidue, the umido-groap, etc 

Thii aptititdafor ddubU decompoaiHon m itlmoul wholly icantinjf 
in emapovHiU wAow haiogeit alow is Utihed la a carbon atom with a 
donbta homt Alkalis do not convert them into alcohole, nor 
slkoxideH into ethers; bnt iiivarinbly, when a reactiori does taka 
plaoe, M haloid iMiid is split ofT, with formation of hydrocarbons 
of the eorios (-'„II,„ .,. 

iAn isomer of «- and fi'chioropropgltn-e, which have be«i 
Inferred to iiborc, is t-alled nfltfl rhioride. Tlie liidogGii atom in 
this t'Oinpouiid tuko« part in double dei-umpoxitioutt a^ euelly as 
tluit in Bii alkyl cliloridi?. Allyl chlorido is obtained by the action 
of phosphunu pentachloride upon allyl alcohol, which can be 
]»re)ttred by a nivthod to be dcecrilied later (168). This alcohol 
yiohU H-pro])yI alcohr.1 by addition of hydrogen, and its hydroxyl- 
Ifroiip nniRt therefore bo at tlie end of the carbon chuiu. Hence, 
UiD halogen atom in allyl ehloride must also Iks uttarhed to 
the end of the chain. bJuwj it takes the placu of the hydroxyl- 
grnup. t'ivL'U tliL- cunslitutionx uf a- and /^-propylcuu chloride, 
wliich ar« dedueed from that of propionuldetiydv and acetone, tlio 
sUyl lutUdes can only liaro the constitutional formula 






CH.=CU.OH,X. 



re the halogen atom is Httauhed to a Hin^dy-linked carbon atom, 
d retains it» iiominl ohamcUfr in stpite of the prc«i»noe of a 
double bond in tho moleoiile. 

Tliis dejiendence of thp rharaeter of a halogen atom on its 
position in the molecule of an tuiBatii rated compound afTnrds a 
eanA of determining nhcthcr it \s attached to a t>ing1y-l inked or 
-linked carbon atom, by ascertaining whether it does or 
does not possess the power t^ take ]iitrt in double decompositions, 
lite following arc examples of individnnl momlicrs of the BeriB& 




158 



ORGANIC CHEWSTKY. 



Vint/J ehloride CH,: CHC'l is a ga^, vint/t bromidt CH,: CHBr «1 
liquid ot ethereal ixlour. Both these compouodt putfmartM'l 
rewlily. 

Atttil cMorule, allifl hromide, and aUgl iodide, boil rvtpexixi^j \ 
Mb AG"', TO", nuU 103"% TKl-v are often tued in syntbeMt for tbej 
mtrodactiou of an oi»»tarBt«d pronp into a conpoond. Theyj 

I bftTO ft chaimctcristic odour reaembling that of maataid. 

Tlie proparggl compouiuU, CUsC-CH.X. mar be nwntiaaed] 

[as a trpe of the seriM C.U^ ^,X. Tbeir constitatiDn ia mfenedl 
from thi' fai't that tbej yield mi^uUic di-riTaiivM, aiioviii; tbat'j 
they contaiu the group C=U, «iid aUu becMiie tfaair habctaj 

I atom M oapftU* of taking port iu doaUe d«o(MBp<MitMBt. sad tg j 
therefore attached to a sinf^ly-Unked «arboD atom. TbcT aia{ 
obtained horn propargrl alcohol ( L38 1 bT the action of pho^bontt ' 
pentabalide, and are litjaids ponesnng a pungent amelL 



The ooaiponai CBBr : C, tromo9oet$tidaK, whidi » aMaaed If 
Xir to cootaiQ a d:TKkmi earbon aiom, can beotatalBed froat aeM|1iaai 
brontdo, ClIBr: CHBr, b; traatiaeat with aloohoBo potwh. It li a] 
gaa, taking fire spootaMMuljr in Uw air: iu acliMtoa la aleokol 
pfto«|Aore«o«ot, oKiDs to slow ondaboo, and tte gee HmU hm aa 
odoar Tttj snilar to iliai ot pboq>boni&. 



tL raurvKAns alooroul 



136. Thv h fdi wi y l -groQp of the nnaattmtad <)f^1wh 
taaMD^y-fiakad or duabtj'linked catboa 



CH,: CHCH,OU. 



CH,: CH-OE. 

To; lev I— fnaadf of iLe l^pe of ■naj\ aledMil aae kiiom. la 

tha m m j o Af af caaa ia wiath tlidr fnnaatiap mi^ he expected, 

|«hcir iaeaen an obtataad. That, vben vaker u ahatiaeled fremi 

gI;tMl, C^OH-CH,0H. theic raaalts. not winfi mktitt, CHOH. 

CH, I 

kataaiMwT.aaflald«hi^ I u ^ 

Wbn /MffMMprapjteM, CH,-CBr:CH,. m fc t atif with 

r.tlMtektonaedaot ^,rdniTTproprlim,CH,Ci(OHK('H,, 

that tlM iwaagiii atatane. Ca,-CO-Cilj It hat htm ^enendlr 

thai in oaan in vhk^ a graa|aig of Urn atoaa b the 



UNSATURATF.D ALCOHOLS. 



»59 



llbnn — CU:C(OH) — would Iw DBtnr&llj expectpd, a traiisforma- 
Itiou into — OH, -CO — occars. Hubstanoee containing hydrosyl 
' itlachod to n doiiE>ly-linke(l carbon atom are therefore uuniable, 

tliiit in, they have a tendency to Iwcome transfonnw] into laomers. 

It uill 1»6 fieen later. bpwKVBr. tliut cunipounda do exist iu which 
|thc group — CH : C((4— is -tafth {240). 

Ttie followos ooinpoundfl elUier contain byJroxjrl attached to a 
doubly -lin):4barbon ntom, or are related to subttaitoefi of this type. 

Vinyl ulciiftoi, CH('. C'HOII, so called because it oontAinti the 
tini/t-gf'>a]\ CK>:C)!— , )trMtiflhly oceum m ordliiiLry ctljyl (Vlhur 
irbicb has filood for isoniu time, and tbcrutiy uudcrgoiio partial oxida- 
tion. When Buoh elher la sliakou up with an alkaline solution of a 
mercary salt, a precipitate of the oompeaition U^iCliOirilli is 
formed, wbioli on treatment with a haloid acid yields viiiyl-eom- 
pouiid&. 

A viiiyl-dorlTative of great pliyslologlcal fniportanco, called neu- _ 

Hue, m formed in tlie decay of dcah, and in other fcrmcutation- ip^*^* 

prooewie«. Its constitution is (CHi),Ncy„ * ', as indionted by the 



followioir bymhe«ia. When trimothytnmiuo reacts with ethjlono bro- 
mide, a sub«tituit>d aiumoiiiiiTn hromido is obtained with the for* 

SiQla (CH.).N<y^^'■'^'*•^^ HBr is abstracted from the group 

— CHi-CH.Kr tiy tbe nclinn of moist silver oxide, the bromine atom 
attached to nitrogvii beip); re|>]nuRd by bydrosyl at the aauie time. 
Asnb»t)in(ie of the conKUintioii indimlMl alxtvo is obtained from it, 
and is in oil rcapL-uta identical with ucuriiie. 



^^^. 



AUyl AleohoX ClI,: CIICII.OU. 

1S7. Many tniiMturitted aU-ohols containing hydroxyl attached 
to B £mfi;lT'linkC4l carbon atom are known. The most important 
of those is nllyl aloAal, obtained by a metliod to he deserihed later 
(168). It« confititution follows from that uf the (chlorine dpHviitive 
tormod by the a^-tion oX phusphonis pcittachloridc. (135). hh well 
u from that of the products obtaiucd by oxidation, by which ullj! 
Icohol is converted firet into an aldehyde, acroh'in, and tbon into 
rylicaeid: 

CH,:cn-cn,on — cu.:(iio<J{ — cn,:Cii(;oon. 



AUri«k<dwi' 




Aorrlic «old 



ORGMHK CHEMISTHY. 

Alljl aloohol mart tbeivfore cuntain tbe gronp — CH,On, which 
if cksracCvrutit; of {jrimury alcobc^. 

Alljl alcohol u It liquid with su irritatiiij: odour, solidifying at 
— iM>', and boiliug iit &i>-5% «ml \a miectMu witti wak-r in all 
proportionfi. lu apccific (rriTity ol i>' in 0-872. It lorma addi- 
tiou-productH with the halogenn and with^ilrogeti, jrielding with 
tli« lalWr n>propyl alcohol. 

Many »tli«r ootupounds containing theallyl-groiACnsiCH-CHi — , 
are known. Of lli«sfl ailsl autphid* ((-'It,:CII'Cl7,S, the pritictpAl 
cnnMittiviit of oil of gaHic, in»>' Iw niDiiiiniiml. It i« nynrh^ticall; ; 
obtalnod hy the action of potaitsltim i(ul|)hkk', K|8. oii allyl iodi<l«. 

Wu havA seen that the influence of the double bond in the 
anHuturatcd halogen oompoundii and alcohols is very prooounced 
wbun it ia Hituuted in the immediate ndghbonrbood of halogen or 
bydroxyl. but tlmt otbcrwiiKi it in much lusts murki-d. Tbo rule is 
tbat when two grouft are ailuated in immetUatt prozimit^ to om 
another in the same tti^lfcuUy each group ex0r£iw$ tt $ironff infiwnc* 
upon th* pri>}?erliti of th« oth*r. 

Fropargyl Alcohol, CUsC -011,00. 

1S8, Prnpargyl ak'/inA voutaiaa a trifile Wuil, Aod is propar^d In 
(b.i following w«y. CH,BrdlRrCll,Rr. iriltromhydrln iiaS). is 
OOUTortud by troatmonl with caitattc potuh into l!lI,:CBr-(!H,Br. 
Tbeii (ntalod witb poUMium jii-«late and tbon MipoiiiUcd, lliis yields 
OUi :CBr-CH,UII, since only tho terminal Itr-ntam Is «apAt>1e of 
taking part in u doublo decamposiUon (ISS). Wlicu ibU alcaliol is 
again brought into ooolnct witb cnojiiic potash. HUr is split off, with 
fonnatfoii uf prMparicjl mIcuIkiI, the cnnMiitniion of which U indicated 
by Ihl.t m^'tlKid of funnntion, iin<l itUoby its prnporlio*. The pn^Mnca 
of ihv t^ruup ■ I'll is shuwn by tbu formation of mnlallic derlTalivea. 
and thill it is a pntnary nicolial In proved by the fitet tbat on oxida- 
tion il yioldti propioiic adrl, GHsO-COOn, an acid containing tb« 
■ano ntiober of carbon ninms. 

Pn>[iHryyl iilcohol in a lii|iiiil of ajcfo^ablo odour, snlnbla ia watar. 
and bdilJDp \i iir~lia' ; lU itpooiflc gravity at 31* ta 0'&68. Iia 
metaliio doriTativea an ozplusiTv. 




KONOBASIG TTHSATTTRATED ACISB. 



I. AOn» OF THE OLEIC 8EEIS8, C„H,n - *0,. 

139. The acids of the oleic serieB may be obtained from the 
Batnrated acida CnH^O, by the general methods for converting 
satorated into unsaturated compounds. 

1. Substitution of one hydrogen atom in the alkyl-group of a 
saturated acid by a halogen atom, and subsequent abstraction of 
haloid acid by heating with alcoholic potash. 

3. Removal of the elements of water from the monohydrozy- 
acids; 

CH,.CHOH.CH,.COOH - H,0 = CH,.CH:CH.COOH. 

^-HydroxjrbutjrJc acid Orolcnilc add 

The acids of this series can also be prepared from unsaturated 
compounds by 
^^, Oxidation of the unsaturated alcohols and aldehydes. 

4. The action of potaaeium cyanide on unsaturated halogen 
compounds, such as allyl iodide, and hydrolysis of the resulting 
nitrile. 



Vomenolatura. 

140. The majority of the acids of the oleic series are named 
after the substances from which they were first obtained, bnt a few 
of the middle members have names indicating the number of 
carbon atoms in the molecule. The first member, CH, : CH ■ COOII, 
is called acrylic acid; others are CjH,0, crotonic acid, CjHgO, 
attgelic and tiglic acids, C„H^O, undecylenic acid, C„H„0, oleic 
acid, C„H„0, erndc add, etc. 

i6i 



Itl2 



OKCASIC CHEMISTRY. 



OeD«»l Fropertlet. 

141. Like all coniponnds coutaiiiiDg a doiiblo bond, the Acids 
of thia aerieit iwsseett the jiower of forming additioii-iiroJRCte. 
Thej" ar» "gtrouger" acida than the corresponding fatty acids 
coDtuiuing the eaniu Dumber of carbon atoms in the molecule; 
tliu^ the value of the coastant K (93) for propioaic acid C,H,0, 
is IJ-W13-I, for ucrylif at-id C.II.O, 0-0058, for biUyftc acid 
C,H,0, 1I.0(JI4», for t-rotunic atiid C,ll,0, «. 00^1)4, etc. The 
double bond uausefl the acidti of the oloic series to he much more 
readily attwkdd by oxidiziug-agcnts than thotto of the fatty sphcs 
(129). The former arc converted by energetic oxidation into two 
eattiratcd ncidis but whoa the reaction i^ restnunod by u^ng a 
dilute eolntion of potAsginm permangnnato, a dihydrosy-noid con- 
taining the gronp — CHOI I ■ C H OH— i« formed as an intorraediata 
product, and on farther nsidation iaHplit up at the bond Ijctwcea 
tliese two carbon atomH (129). Thin aiTords a meant« of ileter- 
miiiing the position of the double bond in the mnlcciilo. A 
breaking-iip of the molecule with formation of sHturatGd fatty acids 
alco lakes pUce when an unutuntcd acid is fueed inth caustic 
potash with ncoeee of air: 



C„H,„.,CH: CH-COOH 
KO H 
KO U 

O 



OlH" 

= C.H„ . jCIOK + CH^COOH. 
0^ 



This reaction was at one time often employe>I to determine the 
poiiition of the double bond. imd«r the imprp»;ion that the docoiu- 
aition «f the molecule vfft« effected at the point where this bond 
ras situated in the first innunee. It U now known that under 
the inflHoiico of fusMMl ciuiKtic pnta«h, or oven by lK>iliug with a 
solution of i?iuistic Rodttj the position of the double bond b«oome<i 
shifted nejirer to that of the carboiyl -gronp. Fusion with caustic 
]iotavli is therefore not iipplicablo to the detormiDatioD of the 
])Ofiition of double botidd. 



AoryUc Aoid, CH,:C!1C00U. 

14S. Acrylic acid U obtained by removal of HI from /3-iodo- 
propionic acid, CH,I-CU,COOH. It is a tiqnid with a pungent 



^aOS OF THE OLEIC SERIES. 



163 




I 



odour, boiling »t 140°, und U roducod by nnaceni KydrogeD to 
propionic acid. 

Aeidt with th« formnlft C.II^O,. 

143. Sereral ncids with tlin forniulii (',(1^0, are known. In 
accordance with tho thooi^' of cunatitutioa, tho following hfo 
poseiblo: 

1. CH,:CH-CH,-C0OH; 2. CH,CH:UH.COOH; 

Four Isomeric acida with the fonmuU 0,11^0, are itctually knovn. 

An acid of the constitution indicated in formula 1, vinylacetic 
mar be obtaint'd Kyn thoticully (23S). U« formutiou by tho 

ou of potusiiuin cyaiiidu uxx iiUyl iodide, uud eupoullicutiou of 
tho nitrile tbu« formed, might be expected: 

cn,: cn.oii.i — en,: en -cn.cx — en,: on. on,, coon. 

Antnally, howcTcr, an acid hariiig the formala 3 is obtained, tolid 
crotoDic acid, which melts at 71^ and bnils at 180°; for it is con- 
tertcd by careful oxidation with pormnngnnate into oxalic acid, 

Hooc— coon. 

IsocTOlonic acid, a liquid boiling at 172°, has also tho con- 
atitntion %, because, on the one band, like solid crotoBic acid it 
can be reduced to 71-butyrio acid, showing that it too contains a 
normal carbon chain ; on the othor, it ia conrerted by oarcftil 
oxidation into oxalic acid. Ordinary constitutional formulie ur« 
incapable, thoreroro, of aocountitig for tho isoniorigm of these 
adds. We shall see later (170) bow it is explained. 

An acid with the formula 3 is obtained by the abstraction of 
Br from bromo-iHobutyric iicid, and is called laethacrylic acid : 

^{{•>0Br.CO0Il — ^"'^CCOOH. 

01«Ic Acid. C,,U^O,. 

144- Oleic acid in obtainw! by the saponiflcntion of oili and 
fats (91>. In onlur lo separate it from the uitnrated fittty 



l«4 



ORCANtC CHEMaTRY. 



addir aUaric aoil piiJmilit- actda, which uv Mt hM U the umft 
time, OM is made of its le«d ntt, whivh iii rcsilily mlabW in Hhvr, 
in contndUtiactioii to thow of tlip Rataraipd fattr acids. The 
okrc wc\A !■ libenittfil from the lend olcate b; treatment with scidg. 

At Mniitinrr U.-nippnitiirM, oleic acul is a licjnid melting at 14~. 
vithout odour and of itu oily lutaro. It oxidizes reiwlilj i» the 
air, and cnoaot bo diitilM without decompotitiou under ordiuarj 
prMmros. 

01«Tc acid contwns a normal carbon chain, Riace it is coDTorted 
hj rvdnccion into alearii; ackl, 

KRAPrr baa proved the normal sirnctore of alearic ncidbyconvert- 
ing It atAp t)}' ittvp ttilo adda coiilaiiiinK a smaller tminlMr of cartioa 
atoms. Ilk niullind U aa follom. Wbni jtubitiiCLM to dry dtstillattoit 
111 a vacuum, barium >l«ame aud barium acetate yield a kctooc^ 
0,»II..-CUCH,: 

0.,H,.| 60bbaMrbaO !Q0-CH. -• C :.H,,OOCH,. 

Dirtun •(««nto Barium mixUM KftmsirlmirlbjlkrtoDo 

On oxidation, thia ketone fialdii acetic aoid and fun acid of tbt 
focmola CiiIImOi. This nliows Ibat iu th« ketoa« tb«re must be a 
OHrgroup next to tho cartionyl- group, ko that It box thit formula 
0>*llit-C'IIi-CO-Cl],, iiiaco onl}- in tbii ciuso could oxidation pnxlucs 
as aoid with seventeen oarlion atoms. Tliis acid, C'l.ilt.O,. {margarie 
acid,) b ooiivtrted in the name way into a ketone, OifUii-CO-CHii 
which OD oxidation yieldH an noid C-«ni,Ot. The formula of 
narsnrio acid must tlivroforu bo Citlli -CIli-COOU. and that of 
•tearic a«i(I. C..1!..CH,.CII, COOU. Tim aoid C.ili..O., paimitie 
add, i« in ila tuni oonverted into a ketone, etc, and the prooeu 
OODtiauod until nn aeli] Ik obtained, ixiprie aoid. Ci.Hi.O.. which 
has been proved hj Hjntbcsis i83>6. 1) to oontain a uarmtil carbon 
olialn. 

Tho presence of a double bond in oleic acid is proved by its 
fomiiiifc an addition -prod net with hiomin»>, «nd by it« power of 
nsdnring nn alkaliuf pcrmnngnnato wlntion (183). The double 
bond Ik Rituati>d at tho middle of the molecule, tho constitution 
of olttic Moid being 

CU,.{Cn,),.CH;CH-(0H,),.CO0H. 



•ha>tBa 



j4aDS OF 7HH OlMiC ANO PROFIOUC St-KlES. 



1*5 



Tbis oonstitntion tu iuferrecl from tbe prodaoU of carofal oxido- 
tiun, which yieHA pehrnjviiic aciii, C,H„-COOH, and asBlaie ncid, 
UOOC-(CIIj,.COOH. 

Oleic acid reacts in a rery remarkable manner with nitrons 
Hcid, eveu when it te brought in contact with » mere trace of this 
milwtNiice. The reaction is best carried out by p&seiiig Iho red 
gw, which is a mixture of NO, and NO, obtained by heating 
iir!ier)ic triosiile with iiitriv acid, into oletc acid, thu same ofT«ct 
imu^ pruduc-vtl hy the adilitioii of uitric acid of 8[>i?.cillc gntritv 
1<3S. The oleTc acid becomes solid aft«r » time, being converted 
into an isomer, elaidic and. Tliia reaction U called the "elaidic 
transformation/' It is also undergone by other iLcida of tliis 
seri«B; thus, erueie acid, C^n„0,, U converted by u trace of 
uitroiiB acid into braasiiUc acid. 

Khidic ueid has the «8ino Ktruclura) formula as olaic acid, the 
doTibli* bond occupying an idcuticul position in the molecule of 
«uch, itinoe i-ach ncid rt^odily forms a bromine addition- product, 
which, by removal of ^llUr, yields the same acid in both caoM, 
G,,H„0, , stmroiie ncid: 

f;..IU0,-C..II,Br,O.-C„II,0,. 

nirto Mill ^Iklillr BiMinln* bldlilnD- Ri«*roll0 aold 

Tlieae two acide yiold the same ketoatoaric acid by the addition 
of one molecule of water, which is ofTcctod by ths action of con- 
centrated sulphuric ncid. Tbo isomerism of oleic acid and elaidic 
acid is tlier^forp, like that of enicic ncid and brassidic acid, 
analogous to the iitomeriKm of the two crotonio acids (143). 



n. AoiDi or TSB paorioLic sebies, Caii,„.,o,. 

14&. The acids of the propiolic series hare one triple bond, 
or two double bonds, in the molerulo. Tbc Qrst-nnmod iiro forrnod 
by the action of rarbon dioxide upon the sodium uompounds of 
the acetylene hydrocarbons : 

CHsCNa + CO. = CUsC-OOONa. 

Bodliun [inlpluUle 

The aridi) thus formed hnv(> » Iriptp bnnd attached to the rr*carhon 
atom. Acids of this uaturt- arc ven' easily split up into uu 



1^ 



i66 ORGMNrC CHF.MISTRY. 

acetylene hydrocawboo and CO,, especidlly on hoatltig their silver 
wlt<. 

A general method for the prepftnition of acide with triple bone 
consists in the addition of two bromine atoms to acids containini 
a double bond, and siib»oqiieat abstraction of SIIBr: 

CH,CH:CH.COOH — CH,CHBr.CHBrCOOH — 
— Cll.CiC.COOII. 

^ TBtroUe add 

Snbfltances containing a triple bond pOB«esa tlie j>roperty of 
adding on water under the influence of ooncentmtcd sulphuric 
aaid, with formation u( kotonut : 

_o=c . — cn.co— . 

Thne, stcjirolic a«id, uientionvd above, is convorted into a koto* 
stoarh acid of the formula 

C,H„-C0-CE,-(OH,KCOOH, 

wliich IB tninaforrned into the corresponding uiimo by treatment 
with lij'droxjlttmiuv: 

C,U„CCn,.(CH,),COOH. 

iiou 

Under the inflnenoo of ooncentratw) sulphuria aoid, this oxime 
undergouH the Bkrkmann traiiBfumiutiuu (112), amoug the 
products being the aiibstitutt^d acid amide 

C.II„.GO 

NU<CII,),COOH, 

which is proved to hare thi« formula by its docompoeitioQ into 
polargonic acid, C',II„C001I, nnd tho 9-aminononoTo acid, 
N II,- (CH,),.C00n, when acted upon by fnmhig hydrochloric acid. 
This is a conlirmation of tho constitution Bbove indicated for oleTo 
acid and ehildic acid, since they can be converted into staarolio 
acid in the wity already described. 



ACIDS mTM TIVO DOUBLE BONDS. C„H„_,0,. 167 

Acidi with Two Doable Bonds, C„H,b_.U,. 

146. Very few of these are koown. Among them may be men- 
tioned «or6^ acid, CtHtOi, which is crystalline, and melts at 134-6'. 
It occurs in the unripe benies of the mountain-ash, and has the con- 
stitution CH,-CH:OH-CH:CH-COOH, as is proved by its synthesis, 
the condensation of malonic acid with crotonaldehyde under the in- 
flaence of pyridiue as a condensing-agent: 

CH..CH:CH.C|?-r-jT- „ ^ COO H 



^ .... iO + H.C<,~"=CH..CH:CH.CH:CH.COOH+CO. 
Crotoiuhlabydfl ' ■ ,COO|H 



HklOOlOMid +H.0. 

Isomeric with stearolic acid is linoletc acid, CiiHi,0, , obtained by 
the saponifloatiou of linseed oil. When carefully oxidized with potaa- 
sinm permangaDate it is converted into a tetrabydroxyBtearic acid, 
CiiHiiOt(OH)«, which proves that it oontaias two double bonds in the 
molecole. 



55^ 



TVSATtrftATED ALSEHTDES AMU KSTOHSS. 



L raiATCBATES ALBEHTDU. 

147. Tbc first member of the tinsstarstcd «ldebyd«s if aeroltin, 
CB,: CH-CIfO. It is obtAJocd br n-morftl of vatcr from 
gWcerol, a procesa best effected hj beatiog with poiiuaiutn 
mnhydnMulpluite, K^.O,, or witb boric acid. It u a oolourle« 
Ijqnid, tmling »t 52 . 4", nnd has an crtTemely powerfol, penptmt- 
ing odonr, to which it owes it« name (actr, sharp, and oleum, 
oQ). The disagreeable, pongent smttll produced when a tallow 
candle or art oil-Ump is L-xttuguidlifd is due to the fonaittion 
of acroluiu. On a-ductiou, it >-iekU aU;I alcohol, from which it 
regenented bjr oxidation. It ia oonverted into acrylic acid by 
farther oxidation. 

It bus the propurtiea peculiar to aldehjdee — the lusoeptibilttT 

to reduction and oxidation, reaiaiBcation in preaeace of aUcalis, 

and the power of forming polymerisation-prodnctB. It jiosevaaetf 

this last prop«rtj in nich a marked dogrw that jt DsuallT becomes 

[wfaoUj conTert«d into a polymvr in the course of a few dav« or 

even buUTB, probablv tirirlc-r iho catjilnic iDfluonoe uf tnkoes of 

impuritiM. The preseace of ttie double liond in acroluin modifies 

[to some extent it« aldebydic properties. This ts exhibited in its 

[tbehaTiour towardH ammoniu, with which it does not combine in 

Lthe same way as acetaJdehyde {"LIS), but in aocordanoe witb the 

rfotlowiDg oqmition: 



aC\H,0 + NU, = C,H,NO + H.O. 



[AcTolein-ammouia is an amorphous, btwic snbstanra, is eoliible i 
[ water, and in its appearance and behaviour towanlti water bears 
resemblance to glue. 
Acrolein does not unite with one molecule of an aeid sulphite, 
witb two, yielding a compound from which acrolein itacif 

i68 





UNSATURATED ALDEHYDES AND KETONES. 



i6^ 



cannot ngnin bo obtainod by the action of acids, wliieli only split 
nS one molciciile of the acid snipliite. It mnet therefore he mp-' 
posed that the other inoleciile of acid sulphite b»e attached itself 
at the double bond. 

Crotoniadehyde, Cn,-CH:CHCnO. 

I4S. fVn tmiaiilebtide resului on tbe s)>1ltltn£ off of irater front 

aldol, CH>-UBlOH[-^U|n| -Cq (l»).»heD it is heated to HO'. It iaa 

liquid boiling nt lOl'lOS', aod u conrcrKid by oxidntlaD vriih silvor 
oiide lau> solid crotonic acid, a ro»cti(>ii wliitli [irovi» It to havo iba 
constltntton indionted by t)i« above formula. 

l^rvparyiftatdehffde, ORsC-C^J^, can be obtaiiivd from a,<irolein- 

nvctal by tbo addition of two bromine aioms, stid &ub««quoal reutovnt 
of 3UBr, by means of oniutic potiuili, from tlio addition-iiroduul tbus 
fonnod : 

CH,:CUC(,^^„^j^ — f'H.Br-C11Br-C,oo^g^j^ — 
A«r«l«I[)ac«Uil Di^iViDCMMiniMiiail 

— CllaCc]*,, „ , . 

Tlic tatter acetal Is enuTerted by nnrmiiiK with dUnte sniphurlo. 
■old Into Iho (H>rTV«ponding aldehyde, nhicb linji tlie Sianio irritnting.1 
action on tbi- mucous niumliiruiiiti u» iicrolctii. 

The bolinviour ut prupaixyialdtliytle wicb alkaliK is rviuurksbla 
It is split ap into ncetylcao nod formic acid: 

a tTKBATUEATED EETOKfiS. 

141. Amoos tb«se muy be mciitioiini mr.i'li/1 oridf, CtllKO. aiuj 
pkoTxmt. CiHiiO. Goib iirc oblaitit-il by rhc- condrimation of acctoaa, 
wilb etiminnllon of nrxter. Mosityl oxido ta a colourl^M liquid, B. P. 
130* aud Bp. icr. 0-844 at 23', is in-tolable in water, and pnssesam & 
strong peppermint -likn odour. It Is ro«Agnix<>d jik an iioaitt iintt«<l < 
ketone im ai?coiini (if ila yielding; an oilme. itiid Wn\g I'.HjMibte of forni- 
iag addilioii'pKMliicta. Ita kctniiic cb-irnetf*!* is fiirHinr injtuifefjied by 
its failiiiE to yield an acid cootaitung the same numboi' of ciirtwa 



i^i 



COlCFOUirSS CONTAnriKO MOBE THAH 0H£ 
SUfiSIITUTING-GBOUP. 



I. BALOOBir DEirVATITXS OF MITRAIfl. 

160. It ia p(««iiili' to rci)]!!^!" all four hyilrogen ubnme in 
methiine, in succesHivp etuj^a, hj the dlrvt^t action uf chluriiiu or 
bromino in prcaenco of eunlight. lodiuo does not react with 
me'hnuc. or with its bomolognes. wliilo the notion of flnorinB is 
very vuorgetic, effooting complete fiabgtitittion. 

In practice, bowever, tliia in not the motliud udupteil for the 
pn-puration of tlie coiniiouiida CII,X, . ClIX,, or CX,. They aro 
obtjiiued from the trilialogcn dcrivativoa, readily propart-d by 
another method, vliich yield tetrachloromcthane or tetrahromo- 
mcthane without any clij1i<?uttj, on i!hlonnB.tioTi or hmmtnutinTi, 
and ar*i convnrtpd on ri-duction into dihiilojfon metlmiip. On 
accdant of thoir importtnt thorapeuticjit properties, the oonipounds 
OilX, are proparud on the lurgc nctklo. 

Chloroform. CHCI,. 

151. Chloroform ia obtained by dietilHng alcohol with bleach- 
inp-powdpf. la thia roaction. in which otidation and chlorination 
go on together, it is siipposMl that alduhyde is llret prodiicod liy 
oxidation of the alcohol, and Is then couvertod into triehloro- 
aiUehjfde, or dioral, CCl^-CHO. Thia giibBtanco is convorted bj 
basee, in this caec hr the slaked lime present in the bleaching- 
powder, into chloroform and formic acid (204). 

Chloroform io a liquid builUig st 61°, and solidifying at — TO". 
Ita 8[>e«ifl« gravity at 15" is 1.408; it ia only very idighlly soluWe 
In water, and possee^g a characturiMtlc othoreal odour and street 
taste. Ita prolonged inhalation prodncoa unconsciotisneaa. whence 
it derirca its ralae as an anKsthulic iu surgical operations. 




Cklirirfunii 
sndtr tW 



hat «n«aUe ■Wti. ami imeampoem 
of lj«)a aad air, yiMimg rMnriiw, hjdio- 
flSTeUoride, OOCV TUt deeaBipo«iti(m 
to » fn» otwt fav eke additiaa of Ijt of 
tiw dilonllBrai m bottlv at Bon^ctisic 



The pn—imliTii actioa of deobol prebUjr dtpends apon 
ibi enwl>wWiwi wHh tb« deeoBpod^Mft-praJBHi of tW rhloro- 
{ofB. tku prarentiftf tbeir «iarc>BtBg s eatalTtie accelenting 
iataMM «a Um daeaayorinea. The btkcc* *(«m <*t ohloro- 
ferm lake part in dcaUe itBomptmOtmt; ihatr uMam echoxule 
jiekl* the tth^ etfer at octbolbniiic acki: 



CHlfcl, + iSaj -OC^ = CH(OC,HJy + 3XaCL 



• 



Fonnk acid can be vbUizMd from «Uorofonii br warming it 
with iHaU aUtalu, orthafoMie a<Tid being probably formed aa u 
ntensMlute ptndnct. aUbMiglt tb« hcter baa not been iaolated. 
Wben cbloroforai ia treated vith an atjoaooa aolDtion of caottie 
fotaA <4(H>, rarboD moDoiide is rrolTed; it b aantned thiit 
ddorametbirleae, CC'I, , ia foiraed aa an intenudiale prodact in 
tfaia reaction. 

Wfaen eUorofonn it warmed wilii aleohoUc ammonw KoA 
fluHk potaah, itt tbrea dilorine auoa are replaced by nitngeD, 
with prod Dction of potaninDi cjranjde. The formation of 
inoicrilea from clilomfnnn, alcobolic potaah, and prinunr anitiMf, 
hea been alread; mentioaed (M). 

CUanpicrim. CdJIOt . u obtaiscd bean cbloroform bjr replac?. 
nau «f lbs bydrogeo atom hf « nitro-crmp by titaUMnt wiib con- 
eriWift^ Bilric acid. The Mnuiitatioii of chkmfilertti is inilrmted 
%gr ila jiMiog netbjlamine on ndootioii. It u a liqaid witb au 
aali'ftly pungeol odotrr. and fo ttuallr obtahwd by tbe distillaUon 
a( pitrie a«id with bl«achiRg-powd«r. to which node of [>repanU»oa it 
ovMtta namn 

MeOil/ltm cJUor<d«, CUJCi, , ia obtained fn>Bi ch)or«fona by redoc- 



HALOCEH OF.Rti'Anyf.S OF METH/INE. 



173 



ti«n vith ziii« •nd hjdrMhIorle acid fn itloaholic •olntlon. It is a 
liqukl^ boiling nt 40*, nad having a spectflc grarity of l'S37. 

THrtwhlorometAan*, or earbon tttrachloridt^ CCi., prwiueet! by 
(be nctioQ of chlorini; on cliJoroforED or carbon dLsiilpliide, is also a 
liquid, and boils at 711°. When heated wUh ojccea of water nt 2B0' it 
jiclds nci «[id COi, Its sprcitlc jtravitj Ja IflfiS m 20°. It will be 
nolkod that th&«e higlior ch!r>rinct «iilM!itiiliflii-pnHltM^tx \\Kvti high 
specific KTavities. The bromjno and Jodiiio campouadii hnro consid- 
emblf higher densities than th« oorrespondint; oUloriiio oompeunds, 

Sroirw/iirm. CITBri , is ohtnintvi analogoasly to chloraform. Il 
mfitm at 7-H\ bniU at. 151*, and has a sp&ojfio gravit; of 2'1)04 at 15*. 
It finds th<;rup(!utic applicHtiuu. 



Iodoform, CHI,. 

IBS. Iodoform U a mbetonco of great importanci!, and is 
obfMDcd from alcohol hy tho action of pntni^Rium carbonate and 
iodino. The intcrmcdiulp product, Cl,CHO, aiialogoiu to 
chloral, has not been iiirilatei:!. 

Iodoform ctii also b« prepar«d hy the plectrolysU of a eolation 
CORtaining Oft g. of palaasium iodide, id g. of sodium rjirl>oiiiiti\ and 
80 oc. of alcohol, in oaoh 400 ce., the t^mpernttire being kept at CO* u> 
OA*. lodlitfl In ftct fme at the anode, so that the nicoliol, KtOOi, and 
I, n«ceMary to the formation nf iodoform, are all pn-Jinnt in tlie 
miitnro. About SOitoftliu jKiiasnlum imlidv in by this method caa< 
T«rt4>d into iodoform, wliih* thv rfni»ludi*r nf thu iodinti is finally ob- 
Utined aa poi«ftsium iodnlo. Tho foramlioii of iodfuto can be aroidcd 
to a great extent hy sQrroiiadiiig tbo eathude, at which uaiuttic potatli 
is fonii«Hl, wUb imrohiiienti nhioh prevenia the potasb from eomiiig 
in ooDtaet vlth the iodine got free nt the anode. 

Iodoform is a nolid, and crystallizfis in ypllow hoxagonnl plates. 

has a pecntiar NklTrnn-likc odour, stiblinieB very readily, amd 
melt* at 11 S°. 

ThpsSR fhanictcristic proptirtics of ioiloforra nmlip Its rorumtion 
aa importAut tetit for alcohol, attboiigh it must be remembered 
that aldehyde, acetono, and sovcntl otlier !a>iib8tanc«e eimilarlr ri«ld 
iodoform. Sii1>8tnDco6 cmitnining the gmiip ('I[,-C linked to 
OTTgeu answer to tlie iottmfiirm tent. It ia carried out by adding 
ioHbe to the li<[uid tn be tes(«d, nittl then catistic potash, dro]) by 
drop, until th« colour of tho todiDu raniahnR. If a largo quauUty 



>74 



ORGANIC CNSMiSTRY. 



of alpohol h present, a yellow pwoipitnto is at ono« fonncMl ; if only 
traoeit, snme tinio huR to elfi|)i>e before tLis tnkt>8 jiliicc. Tito 
r«ft(-.tioii iH xuflidptitly <lplicate to s)inw trnceK of »Irohol iti well* 
iratr^r nrid th in -water, after it h&s hccn coureiilrated a«i mnrh u» 
poambin by repttatct] distillation, tbe iirst fmctiDn in «ach case 
being coUcPtod, 

lodofonn is used in surgery as ad ivDtiscptie. It is wftrtby of 
notice (bat it docs not directly kill the bacteria, but th&t lu action on 
the mioro-orgaDUina depends upon n pmrioui doeompoaition brought 
alMiiil, under the inlliiuiicv of tho hunt of the body, bj h fermcntutire 
a«tioD of the niAttftr sopnrntod fri>m Iho wound. 

Meihijlent: lodiile, C1T,I,. u obminod by Ihp reduction of 
iodoform with hydrioilic^ acid, phosphorus being added to regen- 
erate III (29). It iH a liquid of remarkably lii^h specific gravity. 



U. HAIMBH DEBITA.TIVE8 OF THE flOHOLOOITSS OF KSTHAHZ. 

15S> It is cTident that among these deriratircd Duoierom 
lera are jKyssible. For example, replaoemeiit by chlorine of 
ree hydrogeu atoms in uormal pyntaim may taki- plaw in a 
number of different ■ways; a methyl-group may bu eonvertoil into 
GOl,, two chloriiie atoms may replace the hydrogou of onu 
muthyleiie -group, white the third rcplac-c^ another hydrogen ntniti 
in tlic- molecule, or ull three c-hlorine atomtt may uttaob thomselvt^ 
to different carbon atoms: aiid eo ou. 

The methods for tlie preparation of many of the halogen t-om- 
poandK included uuiUt tliiiti Invading havi' ulruiidy bcL^i mcntioiittl, 
tho Kompounds 0^11^,^ ,-CUX, and CVII,^ , ,-CX,-C,H„_ , being 
obtftined by tho action of phoephorus pentahalide on sldchydfs 
and ketones reepectively (106). (.'oropcninda containing two 
halogen atomit attached to two adjoining carhon atoms are obtained 
by the addition of lialogetia to the hydrocarbons Cn'It ' those with 
four halogen atomii, two of which are directly attucht-d to ci*t:h of 
two adjoining carboy atomx, aro produced by the addition of liiUo- 
gen to bvdrocarbong containing a triple bond; while compounde 
of the typo (.■,il,^,,riIX.ClI.\.C,H„.CHX.CHX.C™H„., 
arc obtained hy luldition of halogen to tho hydroearbona CqH^.^^ 
contjiining two double boudit; etc. 



'HALOGEN bERfi^ATtt^ES OF HOMOtOGVBS OF MFTHAHE. I75 



A general method for the preparation of compoimda rich id 

lalogi'ii from llie saturated liydrot-'arboiiH ie tlie exubange of one 

iriirogeu atom for lialogeu, removal «f lialoid aoiJ by meanii of 

alooholic potafih. tialogeiiaiiou of tK« hydrocarbon CbH,„ thtw 

oliiained, renioval of !L\. n-nL-Wftl lialogenation of tho product, 

and su uu. 



CH,CH.-C£J,Cn.Cl-HCi 



CH,;Cn,-f 2CI- 

Et£]rleoe 



-.ciici.cnci ■ -nci - 

SiliylnDr iFtmctilortitn 



-.0HSCU + 4C1-. 
'CnCI:CCl.+ 2Cl-. 

TrtchlDTocthylEDo 



-* Cn01,-CCL - IICI - CCl,: CCI + 2C1 



- CCL-COl.. 



^^ A geueral method for the preparation of compounds rich iu 
I bromine w»e dincovered by VicroK Mkver, and conflists in tho 
direct notion of bromine on tJie hydrociirbons of tlie series C„li,„ , , 
in presence of a small (jimulity of anhyiiroiis iron bromide, or 
lore Finiply, of irou-wiro. Under llmso eouditions, the aubettlu- 
»i takes pUce very ri^adily, and it \\aA been aliown that each 
rixtn atom of a normal chain only takes up one bromine atom. 
Phii8. propane j-ietils tribioinliydrin, ('il,Br-CHBr01I,Br, 
ii:o ibc prodtx^t is identical with the addition -product obtained 
tho action of bromine on allyl bromide, CIT,; CII*CH,Br. 
When many of the hydrogen atoms of a hydroearbon C„H,„, , 
fcve already been replac-ed by chlorine or bromine, it is no longer 
Blblo to aiihatiliile Iiydrogm by the direct action of a halogen. 
Chlorine has no action on pentauhluroetliuuo, for example. 
tui'XKYn.iT ha£, however, ahowu thai giib^titutton readily takci 
ICC in presence of a *inaH qiianlity of alnmhiiiira chloride, which 
i-I eplita off haloid aeid. Jn thia wnv, pentachloroethano with 
alaniininui chloride yiehls tntraehUroefhylene, and the addition 
of halogen takes place at tJie double bond thus formed, the prod- 
uct being in this inKtunce hexachloronthane. 

Nomenclature, and Indiriduat Hembert. 

154. Clompouuds containing a halogen attached to a teniiinal 
rbou atom are denoted by tlie prefix w, if to other carbon atoms. 
a, (i, etc. (:H,Br*t'H,'CII,Br ie Gwy'-dibromopropsne; 
,ISr'CHBr-CHj i» (aa-dibroraopropaue. 



176 



ORGANIC CHEMISTRY. 



Only a few of the numonmii o-om pounds nf thin gronp wili b« 
described. 

EihyUue bromide U emplovod for syntheses, and as a solveut. 
It is ]>rRpar(Ht by It^iding erbylenc into bromiui? covered ^ith a 
layer of VKter to prevent cvnporAtion. thp additiou tukiug pluc« 
very readily. Ethylene bromide i* a colourless liquid of a^cwablu 
odmir, Holidill'09 »t H"^', boils at 131°, and has n specific gruvitr of 
Si8Sati6% 

EtAffUwcfibHidt. ClltCI-CHiCI. is called "Dutob Liquid." or the 
"Oil'of the Dutch Cheoiistfr," owitiK tu tli< fxoi tlint il wan Qrst 
prejiared at the end of ibe eiKbteeiirlt (century by four Dutch clieiiiists, 
DeIMAN, BfNDT, PaETS van TR008TWTK. ftud LAUWXitEXBonoH, bj the 
action of clilorini.' it|M)ii rthyiuiiu. It is R liquid boiling at 84-9% and 
hfi» n spcoifi« gravity of I -93 at 0'. 

7'rtmfthifl(ini< bromide. CII,Br>CH,'CH,Hr, bidi'-dibrontopro- 
paDe. also plHVKaii imporcaut part in synltiuh-eii, and in obuined by 
addition of HKr to allyl bnimide. CII,-f:H-CII,Bt. prodiicfd 
from lillvl uU-ohoI. This incbhod of furniaiion suggests its httriiig 
the oonstitulion OIf,CHBr-nr,Br. whoa it would be identical 
with the addition-product obtained by the action of bromine upon 
propylene, Clli-t'II : CH^. Sinoo thiK is not tin> cam, the first 
roQittitiitioDal formula given above is of neceasity asslj^cd to it. 
Trimcthylcne bromide is a litiiiid, B. P. 105% ap. gr. 1 ^74 at 17*. 



m. FOtTHYORIC ALC0K0L8 

165. Wbun more tlmii one hydru^^i-n utum of a saturated 
liydrocorboii ij. replaced by liydroxyl. it is tlieorctically possible to 
havo mitre thiin one hydroxyl-frronp in union with n single carbon 
stom. or tfl have eaeh MtlacheiL to a iiifr»rent one U shoubl be 
possible to obtain rompouiuU of the first rlaBs by replneemem of 
halogen by hydroxyl in the halogen conipminds II GUXj. It CX, , 
nnd K-CX,' IJ . When this is atteinpled. for instiinre by hrinfriuR 
IiitJof^n compoimdh of ttiis Ivpc itilo oonlftoi with silver aoelatc. 
with thointeution of stibsequeiUly Bjipoiiifying iho compound thus 

obtftiaed, stAblc noetatc*. snnti aa (''Jii<()c'H'o' ""^ '"'*«'' rendily 

Jormod. Bat on saponiticHtion, a dihydric alcohol'CHf(OH>, k 
not obtained from them, iddebyde resultinj; inntead by the 
elimination of one molecule uf witur. When ijompunudf) of the 



tT{M> [tCCl, ar(> tTented with itodiiiin uthoxide. Kubsttnctt witli tbo 
gfuenil formultt UC'(OC,!ij),, ciUled ortho'tst^s, are obwiiied. 
Oil Mipouilimtioii, howevur, II C(OLI), dout not result, tho oorra* 
epondini; avid being formed iiiKtoad, thruiigh loss ttf watvr. Kthera 

iif dih>-dfic alcohols, siicti as CH,-CII<Qj>*tt* are known, and are 

t i 

called aoftaU (113. 'i). The decomposition of these HobstancoB 
vields. not R'CH(0]I),. but an aldehj'do. It follows from these 
consideratioiis that coinf/Oimtls with more than one htjdTOxyUffroup 
aiinfheil lo the aame carbon atom are )in«fable. We nhall see later 
that it in poiutible to obtain taivii cumpnunds iu certain ea«0)S (204. 
233. 237. and 266). 

Miiiiy iMimpoii nils arc known nontaininj aorerul liydroatyl- 
gruup^, of ^s'hicli nut tnort! tlian oiiv in attocbod to «a<:li carbon 
atom. Some of tbeao are described below. 

1. Glycol! or Sihydric Alcohols. 

180. The glycols are obtainod from the correstiondiag hulogoa 
com])Oiuidii analogously to tho monohydrio alcohols (43): 

CH,Br Cll,Cll,Br + 'ilJ.O = CU^Ofl-ClI, CH.OH -f 2HBr. 

TrlniPibllFue brwrnldo TrliiiFilijrlPiirKlycvl 

The pxcliaago of halugeu fur liydroxyl chh he brought aivmi by 
traatDent with acetate of sllrornr of an alkall-metal, and aa[>oiiifiai- 
tion of the diacetate thua obtained. It caa uIno lie eflotilod by boiling 
with sodium carbonxti- Holutioii. or walrr uiid luad oxidu. 

GlycoUof tho type KCUOlIClIOll-R, in which the carlon 
■toin- nttarhed to hydrosyl are in direct union with ou« iniotber, 
are fnrmod from olelines either through tho incdiuiii of thoir 
bromine aildition-prodiicts, or by the direct addition of two 
Oll-groiipfi by inctiii£ of cturful oxidation with jiotii^fltum perniaH' 
ganate. Iu this way ethylene yieldis the Bimpleel dihydric alcohol,' 
uik'd gif/eoi : 

CH,: Cli, r H.O + O = un.oii CH.un. 

Abolher raeltiod for llto formation of glycoia of this type coneiata 
Id lh« reduction or kelones. Tliis may be eitlier carriod out with ko- 
dlnai in aquvoua wlution, or Irallcr, by clootrolyai^. Fur Ihis purpose, 
the icetuu« is diuolved in dilute sulphuric scid : on pasitliig m citrrcnt 
through t)iifi fiolu(io[], ih« reductioo takes plaw al the cnlhottc. Thus, 
ooctune yinkia /liiuicone, In addttiou to isopropyl aluohul. All tlie 



L 



178 



OROAMC CHEMISTRY, 



I 



gljcota ohiainccl t>j' this luothod ar» disUni^isliad by the iinitiv pin»- 
oon«s. Tlie oonslitutiaa o( pjiucoae U indicsted bj this xytitlu-Mx: 

CH.-COCH, II OH.-0(OH)CH. 

cn.oo.ou, II ciuc'toiiiou.' 

"Wlieii dtsUilecl with ililtit« aiilphiirio noiit. pinAcoTi« iindrr^ioc^ n 
remariuble [ntmiimlccular trKiinfoniuiTiini wliicli uui; be cxi>lAiiteJ 
by ajunming that n bydroxyUgniup chiuigca pUoo with a ntfftbyl- 

(CU.),0(Oin-C'^tl.— tCH.}.0.C^i()H^-H,O = iCH.).C.OO.CH,. 

The Goiitlitattou of pinuvotin mny lie dnluai^) Ttvin its synthesis hf 
X\w Hirii'Mi of zine-ni«tliyi on tiie cblnrSdu itf trImetliylMvtIc nchl, 
(Cn.uCCOCI. jinil Id otiiw wiiy*. 

The msjorilr of the glyooln are colmirlt'sii, viscous liqaid.s of 
Bvet-t tast-e, whence the fieriea ilerivus itd uiiiiic. Thuir lioiliii;- 
points unil sjierific graviUee are considcruWy higher than llmite of 
tlie monohydric aLcohola coiitaiQiug th<^ «nmc namber of carboti 
stome. ' Thus, glycul WJla at Hi7-a°, ai\^ ethyl alcohol nt 78'; 
Rt 0^ tho sjMtrilic gravuy nf glycol im 1 ■ 138, and of ethyl alnohol 
0'80(). The behaviour of thit hydroxy! -group in glycol and in the 
tnonohydric alcohoU is jwrfeetly tmalogoua; exchange of Olt for 
halogen, the foniiatioii of ethers, ■ester*, ami alkoxidcs, and, in tlie 
case of primary glycols, the formation of alilohyties and adds, may 
take plattc in oonuection wllh ono or both of the hydroxyl-gTou[». 
For inetatioo, tho coniiiouncls C'H,OI! CHjCl, qliffolchlarhtfdriu, 
CiI,OC,n,CII,OiI. sh^i momelhyldke,: CII,dc,II,CiI,6c,n„ 
glffrot d\dli\(hther, otr. , aru known. The glycols possess, however, 
one property (hit- to tli« jiresciiet' of two liydroxyl -groups, the power 
of forming auhyJridw, The lirst member of tho eerie*, glycol, 
CH,OII-CH,OH, docs not yield an anhydride by the direot olimi- 
oatiun of water, but a compound of tli« fwrmiila <',H^0 is obtained 
by flmt replacing one hyilrnsvl-group by CI and then splitting off 
UCl: 

Cil.Cl CH,. 

I - UCl = 

OH/ 

EUiyWui oxida 



CM OH 

Otjeol ohlti rliyilrl a 



> 



CLYCEROL. 

This coRiiioiiiid, elhtflene oxidt, boilii at ]4~, luiil Is therefore 
gaectfUi) at onJinarr tvmporattirca: it roadily takes up water, form- 
ing glynoh «p hvdroi'hiorif! arid, forming glyculclilorhytlrin. To 
ottiylene oxiiln \» \\»i\^ncf\ thin cnnstitiitiotiiil rormula glvRii above, 
boi-iiD8c< it yields ethylene nhloritlo when tmitei] with phoKphnrn* 
pentachloride, the oxygpn iitom hcing rcpljiccd hy two chlorinp 



atonu. If the compouml had tho coiistitution 



CU, 



which 



hnow 

Bi-emiinlHn possiblo, but u, howovvr, lei« prohnble (136), it would 
not /iel(] ethylene nhlnridn when thtis treated. 

Some cif the higher hnmoIogHPs of glycol, hetwenn th« 
Iiviiroxy I -groups of whi[;h four or fivp Rarbcin atoms intervene, 
yield aiiliydridiis with a constitution unalogous to titat of ethylene 
oxido. Thoy ehow a marked diniinutiou in tUo power of fomiiog 
aflditinn-products with water; or, in other words, the clasetl f-ham 
of e-arbon atoms and one oxygon atom is not so easily broken as in 
ethylene oxide Itftelf. 

2. Trihydric Alcohols. 

157. The priuwpal rfprouentiLtive of the group of trihydrie 
ulcohnls is fflf/rerul. or i/l^rfri/ie. CjlIj(OH),, In acroriinneo with 
the rule given above, that two hydroxy] -groups cannot attach 
thcniwlvee to the same carbon atom, glycerol can only have the 
fitruiTtnre 

CII.OHCUOH 011,011. 

This structure finds support in the following proofs, 

1. On earcful oxidation of allyl alooho! by menns of potassium 
pfrrmanganate, two UH-groupe arc added at the position of the 
double bond: 

CH,: CII Cll^OlI — CII,Ori CHOH CH.OH. 

a. \fhen glyeerol, C,U,0,, ia cyiwrully ox'uV\7Mr t/ft/rtrrir acid, 
C,H^Oj, ia fimi formed, eom-'spencling to the foniiMtion of aeetin 
arid, C,!t,0„ fmm athyl Hk-ohol, t",ll„0. by evehniigo of two 
lijdrogou atoms for onu oxygen atom, whieh nmkcnt it evident that 
glyrend rontiiiiis one — ClI,01I-gr(nip, Fiirtiier OAidation Oon- 
verts glycerii; ucid into (artruHic aci/f, C,Il,Uj , two hydrogen atoms 
being replaced 1^ ODC oxygon atom, with formation of a new 



OUGMNtC CHEMISTRY. 



carboxyl-group. Heace, glycerol oontiuiiB two — Cll.OlJ-groupi 
iu the timU'uiiIe, eo thai its constitution is CH.OII ■ C'11,0 CU.OII. 
Since Uirtnjnin a(!id, COOIICIljO'COOH, still }>os*oejM.>« alcoholic 
proport icii. tho group CU,0 iniist liavo the coustitiition >CHOU, 
anil t«iuco it must liavo tlie tutine cou^titutioii iti tho moleeuli* 
of givcerol, the structure of tho latler i^ proved tti \» 
0H,0il CHOI! CH.OH. 

'A. A further proof of the constitution ji^ven abore is tlic forma- 
tion of glycerol from tribromhyiiriii (153>. 

Olycicrol is a colou rkiM, oily liquiil of sweet tiistP, 18 Torr 
hy^rnciivipin, iind miKc-ibk' in »11 pnijiurtiuus with wiit<*r Riid 
alRoIiol. but insoluble iu i<lh<:>r. It MU'lidille^t only after stAiuling 
for some tinitf at u low tcmpiTHtun-. but the crystalH thus formetl 
do not. iiuilt bL'I.iw IT . IJ. I*. SaO". sp. pr. 1 2«'. itt 15". Its 
cbciniciil bi-'baviour is oompletely in ncoorduucc vrith the oonetita- 
tioii of n trihydrio akohol. Tims, it yield« three c8tor«, by 
replacement of one, two. or thrw hydroiyl-gronpn. 

Since glycerol is a subfiiaiicB wliieli plays n very imporlniil part iit 
tbc o.-miomy nf imtiiru ns » cuitsliiiintit. of iIk ftiH (IM), its symlicaiH 
fram its dtMuimis m of grcnt inlvrtMt. Tliis wa« efftH't*>d by Fkiedel 
and S[LVA. The slnrtinK-Ewiiit was acetic octd. Thin cau tie ayuijie- 
aized from iU el«me>ril8 in ssveniJ ways, for example by tho (ixldntinii 
of ucoWkleliydfl obiAitifld by Uie mivm of WHUtr on «wiyl«iio (US). 
Tli« dry iliMLillalion o( uiiliiluui niittnlo gave aciviono, whicd was rtv 
duood to iaoprapyl alcohol. Ou diminatiou of walor from tlie latltrr. 
propylfltie wns furmiMl. whidi, on additiou of chlorine, was oonvprtivl 
Into ]in'jpylnne dinli]i>ri<Ie, from whhii triRhlnrfaydrin yuan ubtniiii-tl 
by uwatiii«>nt with indino chloride. Trichlorhydrin wax convvrl«d 
into glycerol by liciitiiig witli watt-r iit 170': 

CH.-rOdll — {;H,C()C!H, — CH.CHOHCH, — OH,CR:Cn.— 
— ClI.cnci.CH.Cl— CI!,t'I-Cncl.Cll,CI — CH,OH.CH01I-CI1,OU. 

i'ri>|>|'lpiir lUrhliinilr TriclilixliyilrlD QlyoVTOl 

1S8. Seviirnl compouuda, dirtioult to prepuro from any Qtlipr 
sulwtjincc, may be obtained from ffl>'«*rol' Amoiig them may he 
mentioiivd allyl ttlcohol, uUyl iodidi?. a-i-rolwin, and isopropyl iodide. 
.lllt/l iih:ofiol, ClI,:CU-CU,OH, can be obtained from ^reerol 
by heating it with oxalic acid, COOH ■ OOOII. Tho nionoronnic 
acid alter of glycerol, tm»of'ormin, 

CH,OHCHOHCH,OCO or CH,OIICH OH-OH, 



CLYCBROL. 



181 



it firel form*^, an iindRr thptie conUttions oxalio acid litaes one 
inoleeule of CO,. >ii)Idiug foriiiii! acid, UtKJlU— COQU, which 
I'liiiibinos witli tlio glvi'iTol to prtHluce nionoforiiiiii. When he«t*d 
iiitire Btroiigly, thin (leoyiiiiKieus inlo allyl alcohol, water, and i^r- 
bon dioxide : 



UH,OH.C'H 



0H |CH,|O^CO , 
H 1 



OT CU,OE-_CII— CH,|0]ll 
lO-OOiE 



AUgl i'tdide is obuiinod by the action of phosphorus and iodine 
on anhydrous glycorol: 

9H. 



CU,I 



CH. 



CllJOII 

CH OH + PI, = CHI + P(OH).; CH 



ClI, 



OH 



CH,l 



CH.I 



- 31 = IIh 

CH,I 



The tri-iodiiydrin, C,HjI,. which is proUbly [orm«d as an inter- 
nti?diat« |iraduct in thU rt'iuHiuii. is iinKtublp, and atouce loseH two 
utoms of iodine, yielding tdlyl iudidf. 

Acrolein (L47) is formvd by tlie elimination of water from 
glycerol : 

l oiTir l 

CH,C— CIIOU; 

i OH~H | 

whereby CH,:C:CBOn should rceitlt, but inuuediatiity chaoges 

iiiU. acrok-iu, Lil.iCH cJJ (136). 

hopropt/l iodide \s formed by the addition of water to a mitturo 
of glycerol with iodine and phoBphonis. In this roaotion, 
pmpylerie, CH.CH :CH,, in formed iis nii i (itemed iate prodiint, 
and is evolved in ibe frt-o statu when care is not taken to have 
sufBcieut hydriodic acid present. By the addition of HI, pro- 
dnfed by the iiitenvrtion of iodine, phoaphoms, and water, ieopropyl 
iodide \i formed from the propylene thus generated: 

err ■ CH :oii, + HI = CH,- cm ■ cii^ 

Vrr-fy[i-nif Iwiprojiyl lodlila 

Fonnic acid (86) is usually prepared by the action of glycerol 
on oxalic acid. As mentioned aboi-e, when these siihBtancea 



iSi 



ORGANIC CHEMISTRY. 



are hewted trOgether, carbon tUoride is evolved, aud the glyceryl 
ester nt formic acid produced. Formir acid is obljiineil from the 
latl«r l>y sapflnitie^itioi], the glycerol being regenernled at Ilia 
same time. This li best curried out by the ndtlitiga of a ir«*h 
f|»iantily o( oxalic aoid, C,H,0,, 'iw\, whose water of vrystalliza- 
(iDT) flllticrls the aapniitiiL-ation nf the eater, the formic lieid dis- 
tUliug nver. The glycerol thufi regenerated is again conrerccd 
into monoformiu by the freahly-HiIded oxalic acid, and the ester 
once mure deROnipoeud by the nddition of a further r|U.intity of 
ostdiu Rcid, etc. H ia iu this w&y poieible to convert unlimiled 
quantities of oxalic acid into fomtio acid by moans of a given 
quantity of glyccrnl. 

lOS. CTlyrrerol exi^t» in nature in large qtiantitioe in the form 
of esters. The fats and oils are glyoerjl tri-esters of lUe higher 
fatty acids, and of nle'i'c arid ; glycerol and the fatty acida are ob- 
tained from thetn by anponificAtion (91 and 101). 

The !Uiponil)(Mili<m of (bo iH-tslora of glycerol with caustic soda <«■ 
[jmc. talcct |ilace in alagos, tho di-iMierB and inoiio-eotert being forneU 
aa IntermcMJiate products; this may tie proved a» fullow^ On ooiu- 
plet« saponification, pure tristeaiiti, at gl/i^t^iyl tristcarute, yields only 
8teuric add and glycerol, aa thai if no intcnut-ilintu products are 
rormixt, a pivrtinlly-siipDnlfled portion, in which tho soap produced liiis 
been dtcoDipoBcd by hydrochloric arid, mid llio glycerol rtmo^eii liy 
washing with wal<^^, sliould cnntnin only imchanRcd TriM4>arin anil 
stearic acid. KeiiluT i HMi-iiHn tmr sti-aTicncid can vii.-hl aculyl-dcri en- 
tire* wiih ac«tt{- Jitiliyilridc. If ihn itii|M>tiillctition lake plado in singra, 
inutioatoariu and disli'.-iriD woidd bv formed, and tiio froe bydroxyl- 
groupsof theglyceryl-reiiiiltio in these coiopoiinds would rmot with 
acetic anhydride (o form acetyl -com pounds. On Ireainient nilb Ibis 
antiydndc, and c(ul)Ne(|Uenl complete wipouillcatiaii, acetic aeid would 
be (iinoiig the pniducta: it baa \kvi\ sliown by experiment tbal ibis 
acttiiiliy tlocs ocunr. 

rtiTcrscly, the fata can be synlhoeized from glycerol and the 
fatty acids; for instance, tristmrtn \i obtained by heating glycerol 
with uxoBHs of rtearic acid under reduced preasuro at SiMi' until 
oepamtion of water cBases. 

When kept for some lime, many fata boconio runad. and develop 
u diHtigrvvuble Hmcll and tiuto. Tliis \a due to atiuuaphcriu ojcida- 
tiou. which is lacilitated by the inltiiettce of light. The uuatu- 
r»te<l fatty acid» become couvertfd into uLhera cntitaiiiing a smaller 
number of carbon atoms, aiid wilhai charauteristic odour and to^te. 



^ 






>^; 






WTROCLYCBRINE. 



lii 




160. Cilj-cerol is oxtonaively employer] in the art« and in 
mwlit-'im-. One of its most import»nt uses U for tlie prepjimtion 
of the tto-callBd " iiitrnglyreriiie. " TliiiteiptoHiTO biua misleadtug 
uauie, fiino« it ia glyccr;! triuitmtv, 

CH.ONO, 

CUONO,, 

6n,0N0, 

TkI not a nitro-com pound (76); lor tin saponification with ulkulis 
it yields glycerol, uud ttif itilrutc ot the correepondiug ulktili-Divtul. 
Nitroglycerine is propiired by bringing glyoorol into contact 
with n iiiixturo of conccntratod Rii1[>liiirio mid nitrin ar.\d»., cnro 
leing wken to avoid a rise in WnipRmttirp. After u time, tlie 
waction-miittire is ponred into water, whereupon the uitnit* 
wparates in the form of an oily liquid of f»int, hRuiIar^hd-pro- 
dncing odour, and t^an be puritii^d by wushiiig with wutur. Wtiou 
perfeotlj pare, it docs not explode epoutaneoiisly. 

Nil ruK'yeerine ia a li<q,iiid. mid a^ lis use in lliia lotm for tMbnical 
porposM would bo miended with dKBculiiea, it is mixed with infu- 
sorial cnrlh (kittselKubr}, wliicli iibaoriM it, foniiinic » soft, plwtic 
IDMS&, tttpmmUt, coniMinlng itttiuiHy 752 of nlirriJijlyctiriDt!, and Oii of 
tli« eanti. Ni trolly er.riao can tAso In: obtniiiud lu tlie solid fortii Uy 
diasol ring ill it«fimiillaniiii)nr>'i Liuncorton (2311. wUicbcinivtrriHii into 
Ml einatio solid rcsombling jujubes in conaistcncc. called "blastiug 
gelatine,*' Thia Kubsianee baa tlie advantage ovi>r dynamite of not 
IcBviug niiy aolid resiJne after cxploBion, Dynamite cannot be used 
as ainiuuiiitloii, lU velocity nt tiX[)I(»tlon Imiiiir fio ((real as to prndnce 
an inapolso too vtolcut fur h guu to resist williout burstiuf;; ttiat <^j>t^ 
exerta a hruant effect. "j^^^l^^ 

3. Tetrahjdric and Polyhydric Alcohola. 

161. Among the letrabydric ulcohole may be mentioned 
trtfthrilol, CH,0n-CII0H.CIIOHCU,OlI, which iK a luitiiral 
piodiiot. That it contains a normal carbon chain in provvd by \u 
oonTcraion into w-aocandary bntyl loiiide, CII,-C'III-CU,-CII,. on 
reduction with liydrioilic acid. 

Examples of peiitahydric alcohols are aroMol and irr/tilol. 
C.H 11^, which are aturi'olsomerg. tw are alwi tho hoxahydric n\v.it- 
hoW dtilatol an/t wannttol, C,II„0,,.b6th of which aru found in 
natiire. Tliwse all haYc normal carbon chains, sin™, liko crylbritoi. 



184 



ORGANIC CHEMISTRY. 



tliey yield n-secondnry iodidf-B on redaction witli bjilriodio acid; 
for example, mannitol U converted ioto 

OH, - cu, ■ cm - cn, ■ c'li, ■ cH,. 

Thny can ke obtained artiftciaily by tli[t> n-diicUoQ oX the corre- 
ajiondin^ atdehydes or kotones. Tlie rcasott for ftadtuniug thvir 
stfreoiBonieriom wiU ap])«ar luter (21S). It id miflicieut to retuurk 
bore that tbe polyhydric nlooliols t-ontain asymmetric ctirbon 
atoou), itidiuattid in Ihu fulluwiug formulai by luiterisks: 

cH,OH.SHoncnoH.5uoii Cn,OH; 

AmhiCol and \j\ilvl 

OH,OU-(5hOHCHOH (*110]I-riI0H.CE,0n. 

Thv preeeuco of polyhydric alcohoU prevents the precipitacEon 
of tilt; Baits of copper, iron, and other meiald by means of alkalis; 
tbus, A tiolution of copper euljihato to which glycerol has be«ii 
added does not yield a preoipitale of oop]wr hydroxide with 
canittie potash. Thie is due to the fonnatiun of soluble metallic 
pompoiinds of tho polyhydrio alcohols, whose liydroiyl-hydroKen is 
rrplacijd by the metal. ThU projHrty is not only pomw«ed by the 
polyhydric alcobo^ bnt aUo by many other compoundscontaininj: 
oevorul hydroxyl-groupa (l&S). 

IT, DEBITATIYES COHTArsraO HAtOOEM ATOM. HTDBOXTL-OmOIIFS. 
HITSa^BOUPS, OK AHIDOOSOnPS. 

162. Wc shall only consider » few of the nnmcroua compouudtt 
belonging to thin rlasa, of which it may be said in general that tho 
chemical propertieia of ite membors arc determined by tlie siib- 
stituents. 

No compoimda containing liaJogon and bydroxyl attached to 

the same carbon atom are known; when their formation might be 

expected, halogen acid is split off, with ]irodnction of iddohydes or 

ketones. It lia« more tlmn once been moittinned that stable ulkyl- 

dcrirativcs of compcnnde tbemsclToi; unstable or unknown, such »d 

the ortho-estcm, exist (168). Thiti is true in this instance, for 

CI 
while compounds of tho tTpoU-CH<Q|, are onknown, deriva- 

Cl 
tivee of the formula R-Cn<jj j, ., are known. Thcso Roh- 



CHLOROETHBRS ^KD H^iOGFNHYDRINS. 



>8S 



JiniceB nre called chiororlhers. AVhon ohiorino is paasoil iolo otbyl' 
ether, which is liept cool aiii3 nway from tlio action of lighi, to 
avoid p-iplosioii, tlie hydrogen ntoniB are replaced bj cWorine; the 
monoenbetibutetl protliict has the conHtittition 

CH,-CH,0CHC1CH„ 

Uvu<>cli1or««Cb*r 

» 

ti» is proved by the aetion tA iinlphnric acid, under whoso influenca 
it takcH lip one moluculi- of water, forming ethyl lilcohol, aceCalilc- 
hydc, and hydru<:hloric acid : 

C,U. II C.IUOH 

>0+ I = + p. 

CH..UHCI OH t;iL-CIi<J;i,=C3,.CH0+Ha. 
MciOiwhTQPiwUwr "" 

Compoimds containing halo^n uud hydroxyl attached to 
different carbon atoms are obtained from the polyhydric alcohols 
by partial exchange of liydroxyl for halogen, and have the 
geiKTul ii!itiio halogen-htfdrins. Tho dichtorhydrin of glycerol, 
C\Hj<OUjC'l, . ia foruifd when a soluiioii of glycerol in glacial 
acetic acid b mturated with hydrochloric-acid gaa. It haa the 
Bymnictrical formuhi 

CII,Cl.CHOH-CH,a, 

since it differs from the dichlorhydrln obtained by addition oi 
chlorine to ally] alcohol, this having the mnHtitntion 

cii,<)ir.oiif:i.oii,a. 

On treatment of the nns^nnmctrical dichlorhydrin with caustic 



potash, epiclthrhydrin, \ 



0H,.CH.CH,C1, , 



^ 



ia obtained. 



iHnitro-cvtnpounds in which both nitro-gronps are linked lo 
the name carbon atom, arc obtainod from primary bromo-uitro- 
compoiinds bj the actiou of potatwium nitrite : 

CH,.CHBrNO, + KNO, = CH.CUtNO,), + KBn 

Tho hydrogen atom in nnion with the carbon atom carrying th^ 
nitro-groupB, can be readily replaced by mt^tuls, ao that thc-so 
primary dinitro-com pounds hare an acidic character (281). 

/'laj/iiiffs in which thelwoamidn-grotipxnrcattadioil to tlioaiinio 
carbon atom, are uot nuiueroiis; ino&t of them have their atrildo- 



'iS6 



ORGANIC CHEhllSTRY. 



groups attAched to ttifferent orbon utoms. Some of these com* 
pounds nre fornie<I by the putrefaction of animal matter, such ttA 
fiesb, and are cUsflod, witb other baeic (ftibfitftucoafonncd in the same 
■way, aa pUma'iiw, Among Ihom may b« mentioned aidavtrim 
{pmtamethylenedianiiue), NH,'C'H,-(CH,),'CH,-XH,. and putre- 
tctju {Mrameihtil»ufdiaini*u), Nn,.CH,.(CH,),.ClI,.Xll^ The 
oonKtitutiou of thi-«e subetances ha« been proved by synlbbsjii. penta- 
mcthvleiicdlamiiii.' being thns obtained: trimethylene bromide, 
Br-t'lI,-t'H,-<iI,-Br, is oonrerted by treatment with potassium 
cynnidc into trimethylene cyanide, CN.CIT,CH,.CH, -CN. Thin 
gubRtaneo is rtnluccd with sodium and boUing akohal. which coii- 
veru the CN-groups into CU,NH,-gioup8 (89), with formation of 
the iliMDine: 

CN CM,NH, 

(CU,K — (OH.), . 

Cn Cii,nh, 

Wben pentametiiylencdiamiue hydrochloride is heat«d, it loses 
on« molecule of ammonia, and is converted into piperiditWt which 
hae thb cliaTficl4!r of a satuntted eerondnry amine For thit; noil 
other reaKuus (387). it U assigned the riD£>formiila given in the 
following eqnation: 



V*H.CH,NH, VH..CH. 

IVniAniBihylBiiRllamliiB llperMlne 



rWben heatc>d. tetmmothylenodUmine and irimethylenediamine 
yield analogmiB uloaud-ehuiii compounds, but less reidily, whereas 
ethylenetliamine i& iuuipablo of doing so. 
A mbstanco. partly omine and partly alcohol, fibooM bu 
rt'ferre<l to hcry. on account of its physiological importance; it 
ia chahne. C^H^NO,, which u widely diHtribnted iu llio vegeta- 
ble kiuj^om. Its constitution is infetrod from it« eyulhesis by 
the inUiractton of trimetbylamine and ethylene oxide iu aqueous 
solution : 

(CH,),N + CII,.cn. /CH,.CH.OH 

OUU *" \ou 



LECITHIN. 187 

Ethylene oxide can also combine with anbstances like ethyl> 
amine, witti formation of ami no-alcohols. 

Choline is a conatituent of a Tery complicated aubstance called 
lecithin, which is present in braia-matter, and also in yolk of egg. On 
treatment with dilate aoida, lecithin is converted intooboline, and a 
tri-ester of glycerol, glycerophoaphoric acid diatearaU, 

/OCO-C„H„ 
C,H,f-OCOC,,H„. 
\OPO{Ofl). 

LecitblD is. therefore, the choline salt of this oomponnd. 




POLYBASIC ACIDS. 



I. 8ATTTKATED DIU8IC ACIDS, CaHtn-tO,. 

163. Many immera of the actds C„H^(C00n), are theoretically 

poasible, and HitTf^r frnm nno another in the positionci at which 
tlte carboaiyl-groiijie arc linked to the cwWn cbaiu. For mauy 
reaeons, the mo^tt iin|H>rtanC arc those whose carboxrl-groupe are 
m imioii with llii- ti»rmiiial carbou atom of ihtf normal <.'haiii, 
th« cuQ/'-ucids (164). On this ttccount, these will he described 
here. 

The j?oncnil methods for tho prrimnilion of the dibasic and the 
monobtieic acids iiru analogous, Tlie lorun^r an; jinKltiwd by the 
oxidation of the oorresponditiK fClyi^ol^ bmA .-iMchydce. and by the 
bydrnlysis of thi* dinitrilcs, althoufth many of thom are prcpiired 
by Hjwni&l tn(>thods. 

Physloal and Cliemioal Propertiai. 

164. These acide arv wdMt'gned crystalliae siibetancva: those 
contaiiiiug more thuii ihree carbon ntoroti can bd distilled in vacuo 
witboui dopompoettion. Many of thom split off water when dis- 
tilled undi>r ordinary prei»iire. 

The melliii^- points of these acids eihibit the same peculiarity 
n8 those of the tatty s<^ids (67) : the inctubers coutuiriiu^ an even 
number of carbon atoms have higher nieltiiig-pointa than thoee 
immediately iiuveeodinf; then], with an uneven nnmherof c*rbou 
atomii. Thia iii seen from the table on p. 1^!). 

ThiK relation ii< jrraphically represented in Fig. .^l, from which 
it i* HOon Ihut tlic melting-poiiitH of the even and uneven eerios 
approxinuite mure and more elondy as the nnmhor of the rarbon 
tttome incrcMWi<. 

A eimilnr jvceniiarity is displayed in the eolubility of these acids 
in water, given in the lait enliimn of the table. The eoiubility ol 
the aeidn with an unoven nuDiber of carbon atoms is much gi'eatvr 

iS8 



n 



I 



X 



SATURATED DIBASIC MODS. C„II,„.,0,. 



189 



\ 





Forniul* 


palnt. 


hvu by WBiKhi Hohiblt 
in 100 Panm of WKur. 




COOH-fOOH 

COtHl.CH.COOII 

CtM>li-ii:»l,l,.(-0OH 

(_tK>HlClM,-C<X»n 

tOOH-iCUiVCOOIl 

(.XK»H(tH,i,fOi;>H 

(X)0ll-(ril,i,-(X'OH 

coon.(Cii,>,fO<>ii 

COOII-(CII,),-C(«Hl 
C0OII.(flI,)„.(»OH 

cyoii.(( ii,,..-ciK)ii 

C0OH.(CH,>„.CO0H 


1B9'» 
132- 

isa* 

67-5- 
149* 

loa* 
]«• 

108= 
188* 

laa* 

US* 

isa* 


19- S al SO* 


,^SI»Utnic«eid 

7 Adlpic«cld 


189. S7 .. 15* 

5-U .. 14.5* 
80. 3 .. U' 

1-44 .. in* 


Plnteltc Bc'icl 


4-1 ..»■ 
O-IU.. 15-V 


Ueouncib V l*n». 
■lintrboi;rlk uld.. 

L>nd wkutti ti r i «i)<^ 
dIcarimsjCic ncid . , 


0.1 „ ir 



• Anliydroiu rmaMn mM, 

than the solnbility of thofi* witli an even number, ami it iliminishea 
in both cas«s as the uumber of fiirbon atams ini'rtiRRPR. 

Oxalic Rcid U & ver; much ntrongur acid than its higher 
homoIogneB, as is ehown b; the HiBEnriiition constants. For oxnlio 




t 10 

nuaaui or OMWX atOM 

PW. SJ.— OBAPHIC HEPIIKSCHTATIOK ok THK Mia.TISO-l*ulS|-s UK TWB 
ACIDd folI.n-i<J. 

acid K is about lO-O, for maJonic «cid. 0-10.3, and for succinic 
ifccid, 0-W)05; for tli« rcnminitig acids it Ima vuhioa which dimiuiah 
with incmue in tlio inimtiBr of cnrtion atuuie.. but are of thu same 
order as the last nuraber. The further the CHrboxyl-groups are 
remorcd from each other, tbo weaker is the acid. 



190 



ORGANIC CHBMtSTRY. 



Oxalic Acid. t-",ll,(t, + 211,0. 

166. Between uxiUic acid »iid formic ac-td there exists a genetic 
intcpk-iii'udcufc; it is possible to iircpuro formic scid from oxalic, 
or couvtTH-l)', uxuliL- from fonniti ucid. Ou rapidly liiuLtiiif; j>(itMi»-,J 
slum or sodium furmnte, bjdrogcu it evolved from the fusiug 
mau, and potassium or sodium oxaliLte is formed: 



KOOC 

KOOt 



KOOC 
KOOL- 



+ Tr, 



The rererse transfonnation of oxiJic iiilo fonnic acid b»e already 
deecribod (198), tuid coiistitnt«« Che ordiuary methotl for the 
preparation of formic acid. 

Oxalic acid m freqiumtly produced l>y tliv oxidatiou of urgaiiic 
Kubglfitiree with nitric atnd; tlius, ii is formed by tb« acciou of 
lliis acid on sugar. It is prepared on the maim faclu ring scale 
by heatiiij; a mixture of caustic potaeh atid caustic soda to the 
poiDt of fusion along with sawdust. A formate is produced m| 
ail intermediatu product, and, un further lieutin;^. luaea hydrogen, 
and is conrertud intu an uxukte. After cuulitig, the m&sa is 
lixiviatetl with water, the oxalute j^uiug into iiolulion; the oxalic 
acid in thou pn^^ipituted bh t-aldum oxaIat«^ by the addition of milk 
of lime, and tiuully obtaiuud in tliu fri-v statu by the action of sul- 
phuric acid. ^ 

Tiio prodnetioQ of this acid by tho interaction of carbon dioxide 
and potassium or Hodium at about 300 ', and its fomiation by tho 
hydrolym of cyanogen gaSjCN-CN, are of theorotieal impor- 
ftnoe. 

Oxalic acid is found in nature in different plants, chiefly in 
species of oxatia, in the form of pottuseium hydrogen, or calcium. 
Bait. It is eometimea found ae n crratalliue deposit of calcium 
oxalttte in plant-celU It cryatallizM with two muitfculea of water 
of cryetalliaation, which it begins to loeo at 30°. The anhydroua 
acid can be mblimod by careful lieatiug, but when strongly heated, 
either atone or with coucentra^ sulphuric acid, decompofivd into 
CO,f CO, and 11,0. The same decomposition takes place wlien 
a solution of nranium oxahitc is exposed to sunlight, CO and CO 
boing onorgcticuUy evolved. Oxalic acid is very easily oxidised; a 



■ 93 



ORCANIC CHEMISTRY. 



The following derivati'vcfl of oxalic ftciil are worthy of moiitiori. 
ThD dimethyl et.ter is solid, M. P. f>i', niii] va used iu th« prepani* 
tinii of pure mRthyl alcohol; the diethyl tttar \i & liquid. Both 
ure prejmrcd hy diBtilliitg h. itolution of unln'drous oxiiliu acid in 
thu absolute: alcohol. The umido, oxauiidr, ('ONn,-CUNU,, U tt 
wliiU; Kolid, nearly iiieolublv in wuivr, alrohul, luid ctbur, and U 

^obtained ab a cryfitalliue (trccipitnte by the A(i<iition of ammonia to 

'ftsolutiou of II diiUkj'I oxuLtto. 

The monoaniidos of tlio dibasic acids nrocallod omic aeidg, that 
of oxalic acid being oxamie acid, CONH,-C00ll. It 19 a riystaU 
llue compound, readily soluble m/A\d water, and insoUible iu alcoliot. 

Malonic Acid. COOH-CU,.CO0n. 

168. The constitution of mclonic acid is proTed by its eyntheeU 
from nuraoohlorotMwtic acid. Ulieii un ai|Uouui! Dolution of potas- 
sium monoi^hloroncvlalo is boUud with jiolJii«ium cyanidn. t-yuno- 
acetic mrid i* formed, and ciiii bu couverled iuto malonic acid by 
liydrolysis of the mtrile-group; 






'*^^'<COOH 



Honoohlorotuado oaliil CvjrBooMvtlc acl<l 



Molojnii: add 



Malonic acid Is a crystalline n-ubstance; its physical pro|iertioa 
will be found iu the tablu on page ISit. VChvu lieated ii little abme 
its melting-point, it loses one molecule of carbon monoxide, being 
converted into acetic acid: 

cooii.cn,.ico6iH = Go,-i-cooH-cn,. 



Bzporionco shows that vt/ien compounds in which two etirboryl'i 
groups are m unw7i with otte carbon atofn, are heated ab</ve thtir 
meliinif-jwints, each molecnl$ loses one moUi-ule of carbon dioxidt. 

The most important com]ioniut of malonic acid is tU diflhy) 
etttr, on account of tlio many impoTlunt *<\iithoae8 wliicli can W 
accomplished by ita aid. It ie u liqnid of faint odour, boiling at 
19R*, and having a specific grsrlty of I -(.itU at 15". On IrL-atmcnf 
with sodium, in the proportion of one «tom to each molLvule of 
eitter, hydrogen ia evolved, and the malonic eeter converted into a 



MALONIC ESTER SYNTHESIS. 



193 



wlirl mass. In tliU rcnction, hydrogen u rcplaood by sodium, 
jieldiiit; sodiomaionie enter, n compociiid of the etructaro 

cooc,n, 

ClINa . 

cooc,n, 

This is proved by trenting it with an alkyl haJide (iodide), by' 
which sodium luUide anil an eeter are obtained; 



C,n,>l + yajCK(COOC,H,), = C.Hj.CJJ(COOC,Hj, + Nal. 

On snpoiiificatiou, thU ester yields a homolo^e ai matonic acid. 

If two atoms of sodium, intjteml of one. ruact with oiiv moluculc 
of uiaJonic ester, tvo hydroj^ti atoms are rc-pluct'd. Both of these 
hydrogen atoms are in thu methylene 'f^r>iip, boonuse, on treAtniont 
of thu disa<)io-c.-ompc>iind with twn molcculps nf an nlkyl iodide, 
the two sotlituu atomH are replaced l>y alkyl, nith produrtion of a 
subscaucc which ou isaponitictttiou is converted into a homologuo 
of maloQic acid : 

C QOC,n, COOC.H, 

C|Na,-)-2lIC,IT,= 2NaI+ C((.,nj. . 

i;oof,u, cooe.ii. 

It IB also possible to introdnrc two difF<>n>nt alkyl -f^nnps; into 
malonic eeter. Thus, when manoiiodionialunit: eHter is tresited with 
imih^l iodide, tbectiti;r of methylmalonic arid i« formiHl, which on 
tre»tmcnt with sodium u^tiii yields a aodio-compound; this ia con- 
verted by ethyl iodide iiiio iho ester of ethytmcthylnuilonifi acid. 

It i8 ofidont from the oxamploK whieh IiaTo boon given, that, 
with nudoiiic tyiior as a starting-point, it is possible to Bynthmize a 
greni number of dibasic acids. Moreover, «ince all these acids 
contain two i^rboxyl •groups linked to the same carb^in atom, and 
have in nommon with mnlnnic acid the pmperty of losing CO, 
wlieu boated above tlwir moltiti^-poiuts, it is evident that the 
maloDt« eeter sytithesis i» aleo available for the preparation of the 
monobaaie fatty aeidft. For etample, mcthylt-thylmaloniL' ucirl 
loses CO, ou heating, yielding methytuthylacotic acid, ideutical in 



bOA 





■94 OKCANiC CHBMiSTKY. 

owiBtimticn with active valeric acid (61). It can be naolved into 
ito two active componenta; 

COOH COOH 

OII,-C-C,n, = CH,-C-C,Ej. 

The malonio ester BviithesiB is one of the most general!^ 
applii^nhlc iiiethofis for the preparation of acida, aod it will b^ 
frequently neceaaary to refer to it later. 

ViCliod of s»rr7JDK «iit dio mftloiuG wUr ■jrnthotli. — Thb it kiways 
•Qei-'ti'il ill [III- rulluwiiig wiij'. Uiiu graniiue-iwilttculv of iDHl»nf<! rsler 
is mixod with a ten j>er cent, solution of scKliimi otlioxidt' (L c<)UiTiilen(> 
in absalulo Alcobol, obtaiticd by tim ac^tion of smliuni on alcobol. 
To this mixture ie added oa« (ua.miue>molecul6 of «n alkyl iodide. 
And the reaorlrni'inixture heated no a water-bath under a reflui> 
0»ndei3Mr nnljl the liquid I* n<>long«r alkAlin«. Aficr th« nl^ohol 
bas b»eii dlstillftd off, tliE» mldui> is troHtcd witli wa.tvr to dissolw 
the fiodlnm lodlilrt fomnpd, find the nikyUinftloiiic ester oxtratltd 
with ether. The oihereol solution ia xlried oTer cjilcium oliltjride, 
tlie etherdislilled off, and the reaidoe puri6ed by fraotionation. 

If it J!) deiiired lo Introduce rwoHlltyl-grnnpsorijihcrgrtiups, lliLitft 
&ccoinpllsb<^d by emplnyltiglwo equivalents of ftodiiitn ethoxldo. und 
two graminoiuoleculiM of iiii nlkjl iotlide. When two {)iffr:ri'nt groups 
are to bu uiibitliluiod, ono of tliom \t lirsi inlnxluced into the mnlecnlc, 
and on auUsBqueut trcHtmcnt vtiih asecond granitnc-aiolecul* of sodium 
ethoiidu and of alkyl iodide, ibedialkyl-tnaloaio estei' ia produced. 
In bntb llieae casea, the romaiader at iho process ia identical with that 
described above. 



BncoiQio Acid, COOH.CH.CH^COOH. 



167. Succinic acid \% a crygtallioc Bubstanco, molting at 18 
luid diBSoIving with rfiftiniltj in cold water. U U preaent in 
amher, in foiuiliict'f] wtiat], inid in many plants, and c&n be syn- 
theticHlly prupiircd hy tlir following mnthoda. 

1. From Rthylrni^ hromideby treatment with iiotiusaiiim cyanide, 
■which convcrta it into ethyltno cyanide, ('N-UI3,-Cil,-CN; on 
,pon ideation, this yields anccinio acid. 



J 




svccifJic j4cm. 



>9S 



2. From malonic acid by treating nioooeodiomalonic ester with 
monoohloroacetic eeter: 



= NnCl + (C0OC,li;>.('HCIl,COO0.H^ 

In thLt reaction an eater of rihanetricarboxylic acid is formed; 
when hvutui] uborn it« molting- point, the acid correapontliug t4 
this loeoB CO, . jioldin^ succioio acid: 

CU,U0OH CH.COOH 
lUUoiHCU-COOH "^CH.-COOH* 

8iAatUtit»l miccinfe acids ata be obtninwl fii tho sxme way. On 
the Diic liautl, Btnrtin^ Dot from lualonif cftter iUvK, but rmin a mouo- 
ulkj'lniiiloiiio eftter, and on the oihVT, Iroui an (i-hulogvii-subeUtiitHd 
estor, <\Un4'i-CUCl-COOCiH>,S7tain&trioaldkllcyl-4UOctDic acids arc 
obtained : 

/■OOC'.B. /CE, cooc,u,/cn, 
CH,-<'^[ N» + Br IOlI = NaBr + CH,*0 CH . 

^cooc.iij \cooc,n, cooc^, \cooc,H, 






g-Bmninpm- 



CK)OH CH, 
SaponiSutjon jiMs ClIiC OH 

[SO^U COOH 



; and finally, splitting off 



COa gires symmetrical dimcthjUacciDio acid. 



CH.-CHOOOH 



CH,.CH-COOW 

Unsymtnetrical sub8titut«d sueoinic acid*, in which the hydrogen 

atoms of only onometliyieno-groDp have beoiirr-iiW-wI. ciin be obiBined 

in aa ao&loncous manner The follovriiiit e<iiiatiQDa indicale tho method 

for the pTftparaiioTi of unsyui metrical dlmetbylsuocinie add: 

lOOOC,nft),Cn|Na -H Brl.O^OOCHj = 

■-Brom o iBubuly rlc 
wMr 

s NaBr + (COOC,H0,CH 0^Co6cH,;-» 

COOU Cn, CH, 

' 6h 6-COOH -* OOOH-CUr-C— COOH 

cddlHt^H, in. 

Succinic acid, and urmmntTica] nubiitituted aucvinio acidn, can 
also be obtaiodd hy the itdiou of nn ctihtinxi] solution of iodine or 



19^ 



ORGANIC CHEUJSTRY. 



bromine upoD moDoeodiomalonic ost«T, or its monoalk;l'deriTa>* 
tivw: 

O OOC,H, CO0C,H. COOC.H, COOC'.U, 

A-Cj Xa +1,+Mtt |6-A' =A-0 CA' +SN«L 

C'OOC^, COOC,H, , COOC.H, COOC.H^ 

By sapnnififation, and elimination of CO,i the ester formed iB ooq* 
Tertvd into tlio dt-'^irod vum pound: 

Glnurie Acid, COOH • CH, ■ CH, • CH,* COOH. 

lei. Glutftric ikt-td CAD tM sytitht?«i»Hl by a metliod whicti rurnishes 
AD cxtiiupio «f another ty]ie cf mnlotiio ostcr )iynth<-4is. It i< ebtAiaed 
by the action of (womoI»c'iil«a of uioiioafxltomftiuuicMteronone mol«- 
«alft of inotliyl«n« iodtdo, snponiticAtion of th« prod oot, nod kpliitins 
off 2C0, : 



I. (CO0C,H,),cn|S«jM|-CH,.ir£NajCn((:00C,H,)i = 
= (OOOC,n.).CHCH,CH((JCK)Cai,),. 



n. COOH tx)ou 
Oh cH.Oa - 

ICOOIH lUOOlH 



CH.-tXJOH 

Oh, 

CH.-OOOH. 



B; nsing ethylene brutnide, or lriinotlijlen« bromide, iiutMd of 
metlijlene iodide, the two malosic-ftcid reeiduea can be Joined lo- 
gather in an analogous manner ihrough a ohain of two or lliroo 
mothjrleue-groupii, and the higher ww'-dioarboxylic actds obtftiiied by 
spUttiDg oD 3CO.. 



Slectro-syothetiB of Dibasic and Otiitr Acids. 

Wlien the aqnooux »olutioQ of an e&l«T-salt of a dibaaic acid is 
«lectrol;zGd, tbe metallic ion go«« to ihe cathodo, the anion to the 
anodo; 

Anion CWIoD 



C,H,0OC.C:i[,.COO K 

■"oiuBiuni ptbrl- 
niftlooMe 



ELHCTRO-SYSTHESIS OF DiB^SIC AUD OTHF.ft MUDS. t97 

This anion, liow«vvr, is not 8taM«: afti>r being lUitdiargod at tho 
anodo. it decomposes into oarbon dioxide aad <.',tijOU0*CU,— , 
ond two of tliuib,' rRnidiK<B unitu to form Baooiiiic ester; 

C',H,0OCCH,-Cn,-C00C.II,. 

Hy this method, it ik powuble to iij'nthesiao thu higher dibodo 
aeiii froin tli<> lower. 

HorKK haa dpvisstl » very miitaMn ap]i:knun.4 (Pig. 3Z) for 
tlii^ rtrctro-stfniktMs. It conitista of two ^Iiihs niiMi.-K which can be 
joined at CO, tlntir i-ontonts buin^r ecpunitud at thin point b; a 
sbwtof piirchiui?iit-ptti»cr. _ B is purtiftlly fiUod withi* eontfiit™te<i 
aolntion of the ester-^iiH, invi A with a solution of potasfeiiim car- 
bonate, 8ini.*e it is only at tho nnodo that the dosiroil aution talccs 
pine*. Tlio ga«« evolved can escape thrmigh E and /", wliirh 
serve nt thy same lime for the introdnctimi of the eloclrinled. Tho 
tap'fuQuel Q contuias more of the soltitiou of the oatorwt&lt. 




FlO. $3. — IIoFBR'B AHPARATTfl POtt Et-BCTBO-SrSTOKSIB. 

Doring the olectrwlvsia tho tup is opciiflil, which o«uev<a tho win- 
tinii to uireulHtc slorly through the iippamtns, I<n'iil weeondaiy 
accionn at the anode being thim svciiiiml. Wlioii // iii full, its con- 
tents ore pmired back into the tu[)-iuniiel. To prevent rise of 
toiQperutnre in I In- noliition, due Id the iicbion of tlie flwtrie nur- 
rcnt, the whok- ttpituratns la pluoed iu water. It will )>e idMKirred 



198 



ORGANIC CHEM/Sr/tY. 



from the fignre thai the anode is very email. This is to obtdn b|i 
it a high density of tfie tiectric currait; that is, the quantity of elec- 
tricity (lUup&rt'B) which Itwivos ihe tlectrode per unit of sarfnco. 
At th« quantity of amous discharged »t the anode is proportionul 
to the number of amp^ree of the curreut, it h dear that a hiirh 
douelty of current cuusett a great many discharged auioos to be 
prt-istiiit lib the auodv, this being uioet favourable for their inter- 
action. 

ThU syntheeix of dibasic acids is an extcnnon of an electro- 
eynthedg carried nut long ago by Koi.»e. lie showed that, on 
electrolysis, a solution of potanium acetate yields ethane: 



K 



CH, ICOO K 



cn, |coo 



CH. 
CH. 



Anioa 



Ottlon 



Bendes this extoneion. many others are known, of which one may 
be mentioned here. 

A mixtnre of a ealt of a menotuisic fatty acid and of an ester- 
satt gives, at the anode, the e«tcr of a monobasic acid: 



cn. 



• COOlK + KiOOClCU, Cll/CCOO.n^ 

lam acBUU PoUwuiii rlUfl «iKVIrjiit<p 



-* CH,-CU,CU,C0OC,H,. 

KUvl hntjrnM 

Formatioa of Anbydridea 

189. Oxalic Knd maloiiie ocide do not yield anhydrides, while 
succinic fit;id, (',11,0,. and glutaric acid, CjII,0,, can he made to 
do flo very readily. The foniiatiou of anhydride is doe to the 
splitting-off of one molei-ule of water from one molecule of the 
dibaaic acid, this being proved by a determination of the moleoular 
weights of the anl)ydndf»: 

cn,— tooiii CH,— CO, 



cn.-co|oH 

/CH,— COOIH 

6h, .-J -H,0 

\dn,-{;ooH 



,0 = P -\o 

9iKCI nlc ftnhrdrUo 

\CH,— CO/ 



These anhydrides are rapidly reconverted into the correaponditig 
dibuiiic acidft by disaohiiig them in water. 



* 



CLOSED-OiASN COMPOUNDS. 



i<>9 



CH,.CO 
A derivative of aucciaic add, suc^axmidt, l >N'II, cod* 

tll/CO 

toine a rrloftt-d ohatti with four rarbou atoms anil one nitrogen atom; 

it is formoil by the rapid ilii^t illation nf ammonium suooinato. The 

Btoras iritiiated at the oxtr'emitics^of u oiirbon chain contAiiiiti;^ four 

ur Gve C-atonu rtiatrt ver}' readily with one another; tlioKC in 

iffaurtor chains onljf react with difliriilty, or not at all. Aoalogons 

phuDomcna wero alluded to in connection with the »plitting- 

ofl of one molecult! of water from the iuij>'-glycolH (166), and the 

elimination of ammonia from iva>'-diAiiiiuc» (182). In both these 

instances the Bplitting-off ia very easily effocted from a carbon 

chain of four ur five C-atoius, but is not jjo^eibte, or k-tidii to the 

formation of very unatabla compounde. when the chiiiu id shorter. 

It will be ut^ce^ary later to refer to other e^tamjilt-ti of the same 

plienomeiiou, of which a Batisfactory explanation may be arrivvJ 

at by a conaideration of the direction of the bonds in Kpaue. It 

iroi asramed (53) that the four atHnitieB of the carbon atom arc so 

directed that they may be resided aa lying tuwardm the angles of 

a regular tittrahedron, of which the carbon atom i» the eeutre. 

In tho case of a Htngle bond bctwei-u two carbon atoms, it \a 

assumed that oiiu afliuity of eauh of these atonu is linked to one 

affinity of tho other (Fi^. 33, p. SOO). The position in apace of 

the C'-at^ine in a chain of three or more members, and tho diroc- 

tion of their nftinitics, are represented in the ligiire. 

U will be wen from this that ia a uoruiul chain of four 
C^tom^ the afflniliee eitnntcd at the extremities approach one 
another clowly, and in a chain of five C-atomx they approach still 
more elouolj, bo that they are able Xn enter into reaction with one 
another. 

A fe«' instances of comfHiundn with u closed chain oontaining 

cii,cn„ 

only two C-atoms, auoh as ethylene oxide, \V art« known. 

The figure shows tlkat the direction of the aflTmitiea mast nndorgo 
a conriderahle change to render possible the closing of the tihain. 
Experience shovH thai compounds of this kind arc uustjiblv, the 
cltMed chain being very wutiXy converted iuio au open one, us is in- 
dicated by the " touuoQ theory " of BxavEa (189). 



200 



ORGANIC CHEMISTRY. 



V- 








Fig. S3. — Spacial Rephbsentation of thk Bonus bktwbbn 3-Q 

C-ATOMB. 

Saponification of the EBten of the Dibaiio Aoidi. 

It was stHted (169) thnt the esters of a polfbydrio alcohol are 
saponifiud in stages, tristearia, for instance, yielding firat distearin 
and then monostearin. The sapocification of the esters of the poly- 
baatc acids takes place similarly; thus, ethyl succinate decomposes as 
follows : 

I. C,H.(COOC,H,), + 2NaOH = (',H,<^'gg2*jj +C,HjOH + NaOH. 

II. <^.H. <C00CH +'^*0H = C,H,{COONa),+C,H,OH. 

In this reaction the acid ester-salt is first formed, and is atterwarda 
converted into succinic acid. Reichrr has shown that the Telocitj 
constant (101) for the aapoiiiflcation of ethyl succinate by oaiutic soda 
has a different value at different stages of the reaction, being less at 



J 



FVMAMC AHD MAUiC AODS. 



sot 



l\' 



tbo ODCl tluia At tlie boffiniiiiij;, Tttg nnotion al flnt takes pla 
ROCordiDK to thn Qnt equation, and finally acoordiiig to the second ; 
tbis affords a sstlsfaolory explanation of tho rarying valuo of th« 
telooity gonataiil. 

IL DKBATIIB&TED DIBACIC ACnn. 

Fnmaric and Maleic Aeida, C^H^O,. 

170. The mo«l important mumlx.TM of the group of UQsatnmted 
uibtieic ac'vie iiru fitinaric acid aud mideic arid, i>()th of whicli 
have tbo formula C^U^O^. They huvo boon madu the subject 
of immcrotiK inTeetigntJons, a c<irDplct« cxpliinatioit of their 
i«oin<Ti«im hiiving been finaUy arrired at by »n applicatiou of the 
principles of stcreoisomerinm. 

Fnmaric acid is somewhat widely diatributed in the regetaWe 
kingdom. It does not melt at the ordinary preesure, but ftob- 
limes at about :iiM>°; it difiMlvee with difficalty in water. Maloic 
acid is not (onnd in natnrc; it taelts at 130^ and is very readily 
soluble tn water. 

Both acids can he obtaiuBd by h«atiug malic acid, 
COOK. CllOU-Cli, ■ COOK, 
^ the purticuhu- one formed betriE dependent on the way in which 
tbo heating is effected. Fiimnrio acid is the principal product 
when the tcmpenitnrc i« maintained at 1-10^-l.SO ' for n long time, 
but when n higher tflmppnitnre i« employed, and the heating is 
(jtiiolfly cnrrietl out, the anhydride of maleic acid distils over along 
with water. This anhydride i^uirily takes up water, regenerating 
the acid. This ih the ordinary mothud for the prf^pumtioTi of the»e 
acids, and it indicatoe that both have the same ^ructurul formula: 

cooHcncncoon-11,0 = coouchick-cooh 



ou u 



This view of their constitution is supported by the fact that both 
scida yield Bucciuic acid on t^atment with snttium amalgam and 
water, monobromosiicciuio acid by addition of HBr, and qialtc acid 
by heating with wattir at a high temperataro. Both acids have 
therefore the same constitnttomtl formula, 

OOOHCH;CH-OOOH. 
Similar isomerism of the rrotonic acids (143) has been msn- 
tioncd. We shall now coiisidor how this isomerism can b© 
explained by the aid of stereochemistry. 



aoi 



t^GAMC CHBMlSTKr. 



Tt WIS ittatfti! in 169 that a single bond between two carbon 
atoUL" nmy be rojireeented ita in Fig. 34. If the t*tnihedra are 






H 
Fm. 81 PiD. 36. 

SniatJI BOMD HKTWBKX TWO CJABOX ATOIM. 

dnwn in full. thf'Q the single bond will be «s repreeeoted in 
Pig. 35. Snpposiu}; the tetrabedra aiv free to rotate round tbcir 
c»mmon Rxis, isanterism oannot be expected for cotnpotinds 
Colc-Cd^, nor hju it erer btfm obmrred. 



or 




QftATBic Staoal ltsrmBHXT*ncis or 




WbiB • Aovbl* bond is praanit, then two 

S«. 37^ and S«. Ftae Nttttipa i< Ika 
OBe fcnotWr ittlMO b 




fUMARrc AND MALElC ACIDS. 

Ft \e seen from the foregoing figures tliat (UffereucM of group- 
ing depends on thf position of ilie groups a and b of out* lutniltcd- 
ron iritli refereooeto the similar grouptt a and b of the other. In 
one case, a may hn over n, and b ovlt />, wliich iti the grouping' 
in Fig. 37 ; aud in the other, n may bo ovor b, and h over a, as in 
[Tig. 3lj. This can be represeuied by the tonuul^ 

and tl 

b—V—a 

i, the two urotouiu acidg wouhl be 

CH,— *;— H n_{ _cii^ 

II and .1 

H— C-— ( OOI I H— <■— COOH, 

[and iumaric aud maloic &k\A* would have thi; formulm 

COOH— t— It H— C— COOH 

1 ii and n. 11 

H— (— toorr II— c— coou 

Trim* Cla 

Ft must now be provinl which of these two formuliK belongs t*'' 

■fumuriu ucid, aud which to m&leic aoid. 
Uftlelc aoid yields an anhydride, wliilo famnric ncid doOii not 
dn so. It wit) be noticed tliat in forniulu 11 the C!iirbnxy]-groupa 
are in jnxtapoaitiun tu oiiu anolhtT. but in furmtilu I they are as 
far rt;moVL-d front cuch other 00 posdiblu. Only in the acid having 
the m-formuU uru thu carboxyl-grou p8 ruprctt«nt«d in upoaition 
^to roMt readily with one another: 

H— t.— COO jH H_(:_co 

II r^ ~* II >0, 

H—C— colon H— C— CO 

Halelc at 111 lUJsIc Mbjninde 

from which it is assuinvd that fumaric acid han Ihe cotuli/uWon 
in<licatc<t in/ortiitilii I. nitd ttiit/e'i^ acid ihat \n for*nula.\\- 

Further (Miuiiideruliun will ghow thai thU ulau iiecounts for the 
'Other known propertieti of these aeidH. It should be observiKl that 
Dpither formula contains au asymmetric C-alum, ho Ihnt iieitht-r 
optical activity nor thu great rcaemblunce iu such properti^ as 
tpociBc gnivilT, meUing-]>oint, solubility, eto.^ due to the simi- 




I 




I04 



ORGANIC CHEMSSTRY. 



Inrity in internal structure charucterJetio of tbo iwii]vrii<m occa- 
sione*! by nu attyminelric carbon atom, ia to be expected. Famario 
and laalcit; aeida do, io fact, display great dillereuces io these 
physical proiii-rtieB. 

Both ftiRiaric acid and malelo acid combitio witli bromine, bat 
the dibromo-JidditioM-productB thus obtainipd arc different. Fmnaric 



110 CO 




HO-CO 



+ aBt^ 



CO'OH 

FiQ. 39.— FuMAHic Acid. 

p CO'OH . 





Flo. 40.— UiBROUOsocaxic Acio. 

^ '^^^ coon 



+ SBr 



CO-OH 



Fie. 41.— MaleIc Acid. 




CO'OH 



Fie. id — IdoDiBRoitesvccuttc Acid. 



ncid yields dibnmMuceinie acid, Boloble with difficulty iu woler; and 
maleic ut-id yaQdibrmHOsuccinic and, much more reudily soluble 
in water. A cousideratiun ut Pigs. 3D to 43 will show tliiii dilTercnt 
acids must rvaiitt from tlii^ reaction. Figs. 40 and 4'^. repreaeoting 
dibromoauccinio acid and laodibromoancciDic arid reejiec lively, 
caanol be made to coincide by rotation; this ia soon more clearly 
from a ootnpariHon of Fige. 42 and 43. The latter mny be obtained 



FUMARSC AND MALEtC ACIDS. 



"5 



from Fig. 40 bj rotstion vl the upper telrahedrou ronnd the ver- 
tical mis, the position of the lower t«tnihc>drou remaining 
n&altorod. It wUl be obeerred from the figures that the order of 
the groupe linked to both oarbou atoms of the ifio-^cida is 11. Br, 
coon from left lo riglit, und alao for the lower earbon atom, of 




CO-OH 



— tmr = 



CO.0H 
Tio. 43. — DtniioMUBvetijcic Acid. 




ocKm 



COOE 



Vtti. 44.— KkomomaijiTc ACIO. 




HO<X) 



— HBr = 



CO-OH 




CO-OH 



7ie. 45.— IsooLsaoiiaacQCiMC Atiu. Fia. -(4. — BuouuFBUUtio Acuh 

ibc other acid (Fig. 40), but for the upper carbon atom it ia from 
right to left. 

When nBr is removed from dihromoMacciuic acid (Fig. 43), th« 
il-atum linked to oiiu utrbou atom, and tlie llr-atom linked to the 
other, are eUminaLud, ^iekliug an auid COOII-CH: CBr-COOH. ' 
Thia rtmoval of llBr could not bu effected if the tetrahedra were 
in the position shown in Fig. 4U; rotation round the vBrlieal asi£ 



7ttCAmC CHEMISTRY. 



must first take place, ao aa to bring 11 and Br into " oorreKponrt- 
ing " po8ition8, ag iu Fig. 43, when aplitti iig off U Br produce the 
acid rrpree«ated in Fig. 44. This nctti eiuily vieltis au »uliydride. 
since the COOII-^oupH are in bhe oorreeponding ptMitiona; it is 
therefore brommialelc acid. 

When IT Br i^ split ofrM>m iM>dibromo8iiccinic aoid, reprewnted 
in Fig. 4.'> (which may be obtained from Fig. 43 by rotation Iu tho 
same way as Fig. 43 from Fig. W), an acid is obtaiiied which 
Ottnnot yield a corresponding anhydride, but is oonverted by 
removttl of water into the anhydride of bromomaleic acid. This 
behaviour re^tE-mbleH that of fuuiario acid, whii;h, under the same 
coudilious. yielilB malmc aubytlride. This acid luuit therefore be 
broniofiimaric arid (Fig. 46). 

U will W MM-D from thi' foregoing that tho conBtitotion aeeumed 
for these acide on etereochcuiical ground* does account for their 
chomicfd properties. Another example will bo mentioned later 
(18S), wliirh altto HUpports the explanHtton juHl given. 

Mateic acid can be converted into fumuriu acid in several ways: 
by keeping it for Bnmu time nt a tom[wnilure above its moltiiig- 
point ; by bringing it into contact with hydrogen halides at orUiiuiry 
tcmperatuTce; by exposing n conceutrated eolutiou of molclo acid 
in preeence of a tnu^e of bromine to the action of >iiinlight, a 
ronctioQ which tnkex pbice only slowly in abBcnc^e of light; hv 
trealiiig the ethyl e»tpr uf malei'c acid with small qtiantitipA of 
iodine; or in other ways. The ease with which nil these deoom- 
poHitions take place »howH that ntaluTc acid \» tho uiietable, and 
fumaric acid the etablo, modification. InvcrBely, fumaric acid is 
converted by dii^tillation into maleie anhydride. Tho mechaiusm. 
of thti»u ruactiouB is not fiiUy understood. 

The taal rcfiction, m well aa that by which malvlo acid is con- 
verted into fuiDario aciil by the action of lioat alone, may bo explained 
by llm uusii nipt ion Ibat an cxcliaiigo of hydrogen aad carboxyl takeft 
plam at one of the doubly-linked C-atoDos: 

H— C— COOU H— (>-CO0H 

II -> II . 

H— t%-<LX)OH tlOOO— 0— H 

Afletylenediearboxylic Acid, COon-CsC>OO0H. 
ITl. AetJi/iin»1iearlKxriiIic arid, the sitDplosl type of dibaaia adda 
onalaining n triple bond in the molooule, ia pniparod by the action of 



DIBASIC ACiDS. 



ao7 



alooliolicpoUuti on ilihromosuccinlc iicid, COOH-CHBr-CHBr-COOII. 
A in«tbod of (oriaatioit indicnliug its conaUtulioR. The aiLvor stilt of 
acei]'leu^(llcArliii>:yli<i ai'iJ remlil}- splits oS two moleoulos of uarboii 
dioxiiJc. KtUi p'roduclioi) of 8)1 Tcr aoetjlene : 

fro;iAg.(=C-ir(:^lAg = 2C0, + AgC«CAg. 
Acel>-leuedicarbox}'lic aci^I melis tit 17.'i'', mid yields a b«ituliriil, 
«7»uUlin« acid potassium oalt, which ii soluble with difficulty io 
water. 



AfRnity Conttantt of the TTnBiitiiratttd Acids. 
172. Likp liio moiiobaeij^ iir saturated acide (141), the dibMJc 
nnMtiirntvd ticid» hnvc grmtcir ulBnity (.'ongtuiits ttutn tlie corn^- 
tponding twtiirated ari^s. For siicfiiiie iiciil. /'= O-OOrjfi.'i, xnci 
for fimiHric ai;itl, K = C>.()'.i^. Tht* strengtli of acetyleiiwHcur- 
boxriir acid ie about etjiial to that of sulphiirio ncid. ThiiH. the 
prvseiioe of a double bond, and ^vcii more of a triple boud, iutcn- 
ti&es the acidic diameter, for muleic acid K = i-l7, or about 
tw1r« timue as oiti«li a& for fiinmric acid. Tbis ehovx the great 
in(lu*ueo whicli tht- diatiiiice betwepn tho cftrboxyl-groups in the 
molecule exerciees upon the girength of those acide. 

17a. Bakter lia-s prepared dihasic acids combining rooro than on* 
triple bond in the moloaiite from acetylenediuarljoxylic aotd, Wlieii 
hfHU'd wllti witter, lia aoid poinMinm salt Is convvrtod tuto ihv potas- 
stuiD suit of praplolt4! aciil (MB), with low of COi! 

KOOC-C«C-iC<>;iH = CO, + KOOr-C'»CU. 

When thfloof^por derivHtiv« of this sah, KO^X^CsCc■). istrmted wjth 
poiassiam fffrricyanidft in alkaline Aoluiion. CuO is formed, wbilo tli« 
two acid-rcsldiiPR imiie at ilic ^.aRie time, wiili jiroduotjon of the potas- 
sinm salt \>t tiiatxtyhiir'linirhojrylic ircitl. KOOC-C-C— C'=C:0(M)K. 
Tlio acid poia«8iuiu ink o( thia aaiil bIbo loKesCO* easily, and the eop* 
per derivatirA of Ihe inoiiobiisio acid ihua formed is converted by 
stiiiilar oxidatioi] IdIo CuO Mod the |Mitiusiiim suit of tUra-ttcttgi&n»- 
dkarliwriilic acid: 

SKOOt;C*C-CHCcu-.K{XK;C=C C = C'CsCC=0-0OOK. 

Theso couiiMmnds arc very unstable, boiiig decoiopowd by Che action 
of light, and in other waya. 

m. FOLTBASIC &CIDB, 

17«l. Acids coutaintnp three carboxyl-firtnips in union with one 
carbon utonr are not kaowu, cxcu^it in the form of estfrs, Th« 



aotf 



ORGANIC CHEMISTRY. 



Iriethyl ester of vietltatuiricnrboxglic acid is obtained fay the action 
of chloroearbonic oeter (849) on sodiomolonic cater: 



r,n,ooc c) + Xi» |CH(C0OC,nj, = c,e,ooc ■ (■n(cooc,H4), 



t'liloicc'nrlMiulc 



When tliut ei(t[>r \» Aapunilied, CO, is split off at tlie same timt!, 
mutoiiic ucid beiug fornicd iiiaiwid of the oorrvxjioudin^ irilxwic 
acid. Tiiia ia aiiotlicr iustmitv of thi? phcuomunoii tUsl untral 
nttfalive ffi-oiifS do not rvtuuin in union with one cart/on atom, two 
being the maximnm number in the caac of ciirboxyl. 

A detirrtption ol the »)'ntheflos of a few of the polyhnsir noids 
will afTonl exiimplcs of the methods adopted for the prepunitioD 
of compouiulM of thta c\as». 

Tribasic AoiiU. 

175. A type ot the tribaeic acids is aaaai'-propanetricarbifxylic 
^«eid, or tricarbftllylio acid, which can bo obtained in several vava. 
], From tribromhydrin by treatment v'ith pntaeeium c>'unide, 
and eapoiiiUcjition of the tricyaubydrin thus fonnod: 

Cllr-CU— til, CH,— CU— tU, ClI, — CH CU, 

6r Ki- Ur "* CN CN Cn ~* OOOH COOH OOOH 

3. From maloiiic ester and mouocliluro&c«tic oster: 
(C,H.QOCJ,ClKi ;-f 2Cl |CH, • CO0C,Hj = 

On saponiflcation of this c«ter, an nvid is nbtninod which on 
litiing heated loses (.'0,, with formation of tricarbailylic acid: 



^'"^' CH,(;OOH 



Cil.'COOH 
tH -CO OH 
CI!,-COOH 



3. From mouoeldurotiurcinit! (wter and malonic ester: 

CH(Cooc,n,>, 



(CAOOC).CH^a+^|CH-COOC.H. ^ -f CH-COOC I 



31 OIHIvblOTVWlOCtulO 



TfVBjiatC AND TETRABAStC ACIDS. 



tO^ 



'hen the eeter thuiii obtained is sajKiDiGed, CO, i(t split off, whli 
'fomiiilion (if tririirbiillylic Acid. 

4. A Hyntlic«iFi peculisr to the |>olyhftaio acide L-ouhiittA in tho 
^adtli(iun of sodioiuulonic 6st«r lo the eeters of unsaturated acids* 
nicb «A fumnric ncid : 



Ka 



at 



(CO0C41A 



NaCHC0OC.H, 
CHCOOC.H, J 

+ If *^ CH-COOC.H, 

CU(COOC^J, 



CH-cooe.n, 



SiipoQifi cation, with eubeequent splitting of of CO,, 3nelds tri- 
rCirbsllrlic acid. It meUe at l(iO°, and ie eaeily eolublo in vator. 
Acouitte aciil, M. P. l!il°, ie a tvjie of an nnsaturntetl Irihai 
}atiit. It is obiaiceii from citric, uoid (198) by the ellminatioE 
' o( water by heating. The coiiatltution of aconitic add is 

CH^=:C CH, 

COOll OOOH COOH' 

■inoe on reJuctiou it ie ootiverted into tricarballylic acid, 

Xttrabaaio Acids. 

176. Some examples of the synthetit; methodn employed in the 
preparation of the tetrabaaic acids liave be«n already mentioned 
in Connection with the gyntliMpfi of dibauic and tribRKio arids by 
mvans of malonic ceter. lu tlie^- reactions the tetrahimit? iw'uU 
are often formed as tutermcdintc products, being converted by 
Fjililiing off one or two molecules of carbnu dioxide into tribuaio 

tand dibaeic acids respertively. This reaction, howevfr, alvroya 
yitldfl a«dB containing two carboxyl-groupe in union with one car- 
l»n atom. wafica'-Iifitanetetracarhoxyiic acid, in which only oi 
carboxyl-group \& linked to each t-arbon atom, can be obtained by! 
uplittiug off 2 CO, from a hesabaaic acid, tva^ff^uj'-bvfttHehfracar' 
btttyhc acid, wliicli is itstdf obtaintd by the action of iodine on 

Etetricarbozyiic tfter (187); 
c.n.oocOiJ.IJ, 
kiiiIlMa*irIc«rt>ox)rlie ntvr 



CK,.tOOC,l{, 



(C,H»OOC),C|Jfa Ntt|CtCOOC,HJ, 

in,cooc.n. 



(COOC^J, 



C(CO0C,U,), 
CH.COOC.H. 



310 ORGANIC CHEMISTRY, 

CH, C CH. 

H. I /\ /\ 1 - 

COOHiCO.lH COOH]CO;|H COOHCOOH 

■■ilSiM'-BuIuirhezBcarboij'lic *dd 

CH, CH CH CH, 

~* COOH COOH COOH COOH 

•M^H'-BuUnetemetLrbozf lie acid 

Higher Polybasio Aoidi. 

177. The last example shows how it is possible to obtain higher 
members of the series of polybasic acids. Iq general, the hydrogen 
atom in the eaters of acids containing a carbon atom in union with 
two carboxyl-gToups and one hydrogen atom, is replaceable by 
sodium. When a sodium compound of this kind is treated with a 
halogen derivative of a polybasic acid, a higher polybasic acid is 
formed, the same effect being produced by means of iodine, which 
causes the union of two molecules. These reactions afford a 
means of synthesizing numerous polybasic acids, the ester of even 
a 14-bB8ic acid having been thus obtained. 



SUBSTITUTED ACIDS. 



■cid, 



III thet»e acids there is no liydrofroD in 



I. B&LOOEH SUBSTirnTSD ACIDB. 

178. The halo^n-siiListitiiUiI iicrids ciui he obtained bj the direct 
action of chlorine or of bromine upon the aatnratod fatty aride, 
but this prowiw Ut tint von,' jiatiBfnrtory, The monochiopo- 
acide mid monobromo-Jinids mn he Iwtter preparfld by the uetiitiL 
of chlorine or hromine, not iipnn the acid, but upon ite chlor* 
ide or bromide. The prooesa in carried out by treating tlie 
acid with phofiphorut! luid a huhigim, the phusphoruH balide pro- 
duced reacting with tho ncid to form an ncid chloride or bromide, 
B-COX, which i* then attacked by the ciccsb of halogen present. 

Some acids cnniiot he brominated in this way: for example, 
trimethylacetic atrid, (CII,),C-CO0n, and tetramelhylaueclnic 

(cn,\rcoon 
(cnj.ccooH" 

Doion with the a-oarbon atom, which is directly Hnked to 
earboxyl. As a general rule, it is only poaiiiblo to hroniiTiato aoiils 
of which the a--cart)on atom ih linked to hydrogpn, the arids 
formed being called a-bromo-ueidB. The constitution of these is 
proved by converting them into hydroxy-ncidB {182>, which are 
ehowQ to bo a-compouuda llirougb thuir «yutheei« by another 
method. 

HAlog«n-BnbeMtut«d acids can nlno be prepared by addition of 
hydrogen halide or halogen to the unsaturated acids, or by the action 
of phoephonis halides on the hydroxy-acids. The iodinated acids 
cao aODietimes be lulvantngeou-tly obtained From the corresponding 
chlorinated derivativcH by henting them with potosfiiiim iodide. 

The introdnction of h&Iogoa into the molecule caueesa marked 
inoreaid Id the strength of an uoid, m will be seen from the table 
OD Dextpago of dtesooiation constants. A". 

9It 



ORGMWC CHEMISTRY. 



KUM. 


rofmnlK. 


K. 




CH,Br.(X),U 

ciicu.ro.H 

CH,CH,-rO,H 
CU,I<il.-CO,H 


0-0018 




O'lU 




O-IW 




0-075 




181 




0'00I34 




O'WOU 







This tabic allows that the Ktrcn^h of an acid is iucroaaod to a 
greater cxt<'fit hy rhiorin* than by bromine. ntnJ by bromine than 
by iodine, iinil thiit llio introduction tir nion> than onR chloriue 
atom occnuons n markixl inorcoM) in the Ktrengtli of the acid. The 
position of thp Iui1og«n atom also exertii an influence; for iodoacotie 
acid, in which the 1-atom occupies th« ff-posiiion, the value of the 
constant is 3'i timoe as ^re»t as that for acetic acid, while for 
/J-iodopropionic acid K le only 7 times aa groat &e (or ptopiomc 
acid. 

Tb« influeiioe of the carbozyl-groiipd upon tlte lialogen atoms 
te suoh that the jtrofm-ties of the monohnhgtH-UHbfdtMted acids 
depend cltitjtif ujjoh the relative petition of the lialogen aloni and 
the cttrboxyl-grovp. 

On boiling with alkalie, the a-haloffcn-SHtatitated acids are 
eaaity converted into the K-bydroxy-Bcids by excliaag<< of halogen 
for hydroxyl: 

cn,ci.coon + Kon ^ kq + oh,oh.cook. 

]|«aoehkmMrU« Mid PotHMtann Klrwllua 

Under the same treatment, the /9-halogen-«nhRtitntod acids 
split off hydrogen balidc, with formation of iiDsatnmted acids: 

0H,CIIUiCIl,-UO0U = CH,UH:CH.C0OH4-HCL 

5<;)i \omhMft\c uai C'ratonie acM 

The beliaTJoiir of the /l-halof^ti'Sobelil utvd aclila wUon treated with 
sodium cartx>iiat<> is very characteri-Mic: wlicn Ilioy aru vanned with 
an aqusoua jtolnttan of it, not only Li liydrogeii halide eliminated from 
the molecule, but C0« is split off ivt the same tiioe, with formatioD of 
an nnsaturaled Iiydrocarboo: 

CH,-CUL'UiCO,lNa = CHiClIiCHUU, + NaBr + GO,. 

Dtitflcne 




HMLOGEN-StJBSTlTl/TED AODS. 



»t3 



On>>oiling with water or with nn »IkaIi-PHrbonato,the ^-halogpn- 
euWitutt-tl iK'i(l.>i rejMlilv split ofT 11 X. forming » jwoulisr cliiM of 
cuinpuiiiiib kiiuwti IIS hiclonej' (183 unU 188) : 



CH,-C11-C1I, 



fH,-CO- 



►CH.-cn-rn,-fH,-co 
I . 6 



VolproUotODB 



Cbloroaoetic Acidt. 

17». MonochlormcetU! acid, CH,C1-CCK)H, is obtained by the 
action of obloriue upon acetic ncid, in presence of siiljibur lu a 
chlorine-carrier. It is a cr^-stalliue soliti, melting at ij3°. IHchhro- 
actiie and, CT!C1,-COOH. and incfthroa^edc acid, CCI,-C00n, 
are beat pre|)ared from chloral (204). Trichloroacetic acid is 
unstable, uml is docompo^cd on boUiug with water into carbon 
dioxide and chlorofurm: 

cci,|rg;jn = cci,n f co,. 

This 19 another cxiimple of the fact that " loading '* a carbon atom 
with negative clcraonts and groups makes the compound in which 
it is uoDtainod uuBtnbJc. 



yS-Iodopropionio Acid, CH,I-CH,.OOOH. 

180. /i-IutlvpropioHic acid ie eouietiuioa iiHod iu eyntfaMM, anil 
is therefore of i>onie importance. It forma well-deflned crygtala, 
■lightly actable in cold water, and melting at 82". It is obtained 
by addition of hydriodic acid to acrylic acid: 

0H,:CH.C00n -|- IH = OH,l-0H..COOn. 

As a general rule, addition of hydrogen halido to acids contain- 
ing a double bond between the n- mid (i'Cathou atoms, denoted 
by .^•*. results in the union of halogen with the /^-carbon atom. 
Thi* constitution of /If-ioilopropioQic acid in dediK^od from its 
tranftforjuatioD. into succinic acid in the following way: 

ON |KTT| 0H.CH.-COOH^CyCH..CH..COOH-^ 

-.COOH . on,. CH, . COOH. 

SuDuiiUcacid 



214 



ORGANIC CHEMISTRY. 



Adds coBteining more than rae Halogen AtoB in the Koleeole. 
181. Isomerism in this type of componnds may be occasioned by 
a difference in position of the halogen atoms in the molecule. Addi- 



C»H„i 




Ou^jOOtB 



FiQ. 47.— Ebdcic Acid. 
TVaiW-fonnalm. 



C|H„< 




H Br 



Kotsied 



OaH«CO,H 




C,H„ 



Fig. 48.— Dibkohokrocic 
Acid. 



Ou,H,jOO,H 



Fie. 49.— DlBHOMOKUUCIC 
ACtD. ' 

Each H-atom in comspoDdlDjf 
poBition to ft Br-atom, 



tion of halogen to an nnsaturated acid results in the formation of 
a compound in which the halogen atoms are linked to neighbonr- 
ing carbon atoms. 



HALOGEN-SUBSTITUTED ACID^. 



aiS 



The Bplittiog off of hydrogen balide from acids of this class affords 
a strikiDg example of the Talae of stereochemistry in expIainiDg phe- 
nomena for which the ordioary oonstitntional formnle are nnable to 
account. It was mentioned in connection with the stereoisomerism 




C»H„ 



-hBr, = 



^CHtfCO.H 




Fig. 60.— Brabsidic Aom. 
CU-formula. 



C|Hii 



itiiUted 



----^o^n^<x>t'B. g 




CuHMOOtS 



FiS. 51, DiBBOHOBBABBIDIC ACID. FiG. 58.— DiBBOlIOBRABSlDIC ACID. 

One H-atom in oorrespoading poeitioa 
to one Br-atom. 



of the unsaturated adds that the dibromlde of one modifloation 
splits off 2HBr very readily, yielding an acid with a triple bond, while 
with the dibtomide of the other modification, this either does not tnke 



ai6 ORGANIC CHEMISTRY. 

pliica at nil. or «aly nritb groat difflculty. An exaniplt; of this is 
ulTonltjd by onioio and briwaidie flcida, which have been proTwl, by ibe 
invthod indicated iu 146, to hnv« tlio coiwlitution 

C.H„.CHiCH.C„H„-a>OH. 

On addition of bromine, and BDl»cqni(>nt heating with akohotic potaab 
at ino'- 170% dibrumoenicia ti«id enslly lo«es Sllltr. yielding behtnolic 
Of^d, CiH.i-t'»C'C,,H„.COOII; whil« under the Bame Iroalmeut, 
dibruniobniasidic iiciil sj>iila oil one inolocule of hjilrobromlc acid, 
with production of a monobromoenicic ftCuL This dllIer«DC« is 
accoiiumi for by assi^^ning tlio /mnjc-rurniuU tu crude, aud th« cU- 
formuU to brassidic. ncid, as indicated in Figs. 47 to 93. 

In the formula for dibromoemcic acid, the lotrahedra may tie 
rotated m> aa to bring enoh Bi--atom above a H-alom <17(l}, umlcintt the 
«1in]i[ihtii>n ot SHBr po!t»iblA (Figs. 48 and 49): while in tlmt (or 
dibromobrnsi)iili<; acid, only one 8r-atom and one R-aiom can he 
brouglii. iuio the '' correaimndln^ |)osi(iona " to one another (Figs. 51 
and 52). 



n. MonoB&sio htdboxt-acidb. 

1B2. The hydroxy -»<;!(]» nre aubstauces containing one or more 
hydros yl-groiipa »ml c»rboxyl-(n"'"ips in the moloiiulo. Thr 
geuem) mothods for their formntion depend u|voti tho introduction 
of hydro xyl-^on pa and «nrl>oxyl-groupg. TJiey are [irotluoed in 
tho following reft(;tioTi». 

1. By the careful oxidation of polyhydrio ulcohoU: 



CH.CHOH.CH,OH 

FropjrtBoeitljcal 



CH.CHOHCOOH. 

Lauito aold 



S. By replacement of the halogen in Imlogen-sutislituted Rcids 
l^liydroxyl, aa alrwidy deacriliod (156j. 

3. By rt;duction of tlic ftldehydic at-icls »nd kelonic acida, which 
contain both u curhoxyJ -group rtnil » carboiiyi -group: 

CH.rorooH + 211 = lh, ciioncooH. 

Pyniraramio oclil L>aciic meiil 

4. By tho action of nltrone acid upon acida coul«i&ing an 
amido-group in tho iilkyl-residne: 

NH,-CH,COOH + UNO, = OH,OH.COOH + N, + H,0. 

QlTQooeU Olycolllo acbl 



MONOBASIC HrDROXY-MCIDS. 



«»7 



S. By nddUion of Lydrocyauic ncid to aldehydea or ketones, 
and liydrolysu of thi> uitrile tliuB ubtaineJ (110, 3); thU method 
yields only a-hydroxy •acids: 






y 



\\ 






c.^«*(^?f + 211.0 = ( „n.„^,c^oon + nh.. 



Cynnliydrlii 



I Hxlroucykoid 



By 9XoliaiLge of Br for OU, acids which havu bi>cn brominotcd bj 
the method de»oribfd in 178 )ncld hy<Iroiy-ftt'id8 ideiitioul with 
thoto obtaiii«il by this i-yaiihydritt synthesis. It follows that in 
thtse acids the bromine is iu uiiiou with the n--carlHm atom. 

1. Oxidation with potfteeiiira permangHUate efft'cts tho directl 
replacement of hydrogeu byliydroxyl ina«ids cotitaiuiug ahydrogcn- 
atom linked to a tertiarv carbon atom: 



^§«>CIICO0H + 



■ Hyilmzyhiotiutyrto Mid 



Fropertiea. 

183. Diflerwiit «om]iouinIa are obtained from the hydrosy- 
by Bubtttitutioii in the hydruxyl-grouji and carbo it yl -group. When ' 
the n<a(am of thu hydroxyl-^uiip is replaced by Mllcyl, an add 
eth$r ia obtained: 



CH.OHCOOH 

airn>lllo avid 



CH.OI .Hj.C'OOiJ. 



EllijUljcollU-uld 

Lflco an ordinary etht>r, C.,H^.,-0-C„Il„„,| , ethylglyooUie add 
(•annot be Riponiflod. When, on the otlier baud, the ll-ntom of 
the curboxyl-gruup ia oxchungod for alkyl, an wtcr is produced: 

CII.OHCOOH -.CH.Oir-COOO.H,, 

Zifayl s'ymllnu 

Like other cetors, tboso compounds i>aii bo saponiflod. 

The introdaclioi; of liv'lru.xyl dtronKthuna tho fatty acidi to an 
extent dopendont on it« position relative to the wirboxyl-group, an 
effect analof^ons to that jtroduced by the halogens (178). This 10 



*i8 



ORG auk: chemistry. 



seeu from the folloving table, coutAining the ralaes of the dls- 
acKnatiiin constant, A', for B«reral xcids: 



Xitin». 



Ac«ttc Acid ,. , 

(nv«i>m« Acid (n7droxr4«4ile A«td) 

Pro|ii<'iiii" Anid 

LaaU: Aclii (a-llydmiyproplonic Add). . 
/y.li]nlnisy pri)pii>u 'c Atid 



Pamiulk. 



CH.-COOU 

C'ii,ori-C'>oH 

CH,.tH,-a)OH 

CH,-CHuH.CU)a 

CH/tH-CHf-COUH 



r. 



000190 

o-oias 
0-ooati 



On hcauiig, tho oi-h^drtai/-ac\d$ L-aailj loee water, tvo mole- 

cnlos of llic Iiittcr liem^ minu1tnii(>ous1y ^yWi olT from two inolociilcs 
of Rcirl ;tliU renction tiiki-u plAoo between tho liy(lroxyl-gmQ|i of one 
molernlp «)i(] the carboxyl-gronp of the other. In this wny, lactic 
acid vieldti lactidc: 



CH,-CH| oiT H |OOC 



CH,-CHOOC 

Ooo— rircri,. 



Tho formula of this compound ehowe that it ia a double ester, ita 
constitution being provod by \U bohaviotir when boiled with watpr 
or dilute acids: like thw ntiterg, it ia wiponified, yielding laclic aoid. 
fi-Hydroxy-aeids rpudiiy gplit off water, with formation of 
unitaturutod ucids; 



= H,0 -f OH,-CE:CUOO{)H. 



CILtUCHCOOU 

^HyilnxT) billy lie mI>I 

When ft /^hydroXJ■-(lcid is boiled willi vxcowor n 10 percent, solu- 
tdoc of catuitic aoda, it is partly vmivfried iiilo xn aj9-,and pnnly into 
a jS^-unsaturated acid, while a portion roniuiiu uiiactod upon. An 
eqatllbrium Is thus rciftuliod : 

R.0H:CH.CH,.COOII '^ R.CH.CHOUCH.COOH 



^R.CH,.Cn:CH-COOH. 

If thi« r«inctlon isreallj'n rerorsibloonc, the same point of oquilibrium 
sliotild be readied by slartiiit^frum lh« b)-«lrox;--acid, or from either of 
Hie iwo nnsatumtod acids. IIttig prared tbat this \» actually tb*< 
ca»e. 



GLYCOLUCANO LACTiC ACIDS, ^19 

y- and rf- hydro jy-acifis lose w»ter, with formation of inner 
ridefi> c»Ued lactones (178 and 186) : 

CH-CH,CH-00 CILCH,-0H.CO. 

loll ^|o ' 

T-Bj-drozrliutjnic acid BuijrulacioDB 

OlyooUic Acid, C,H,0„ 

' IH. (iiyc(^lie actd Is jinwent in unrijie grajM-w. It Is lutoally pre- 
parod by trcAtltiK monochloroacotic ncid nith cauetk potash: 



W: 



COOU-Cnt lOr+Kl OH = COOU.C'U,OH 4- KCJ. 

Glfcollic ncid U-a cryetnlliae solid, molting at 80'; it is rery readily 
Mdilbl^ in vxirr, iilvttlinl, and I'tlier: Wm culciiim khII ilissuli'M witli 
diflSculty in wAlf>r. Whtn diatiUed in ixtcuo, glycoUic ftctd Bplita off 
water, with formation of gljreollido: 

OH,{>|infOlCO CH,0-CO 

I I = aH,o + I I 

00 [JTHol c-n, CO-O-CH, 

Olyoellld* 

lactic Acids. C,H«0,. 

185. Two laeiic acidn are known, diflering from one another 
in the position ocwipied by the hydroxyl-groiip; Ihey «re 
a-liydroiypropioaic Muid. (_'lI,-CHOtl' COOlI. and /J-hydroxy- 
propionic ncid, C11,0H • CH,- COOH. The firdt of theBo ia oniinnry 
lactic ucid. 

<r<H>*dr(]x J propionic acid can be obtained synthotic&]|j by 
the met^tKls duscrilied in 182, aUhuiigh it is usually prepared 
by other meanA. In preseiioe of an organized ferment, mlled the 
"lactic arid ImciUus," curtain Miigant, aiich aa milk-sngar, cane- 
SDgari and grape-siiKiir. undcrfio " lactic tcroiuntution," the prin- 
cipal product being laotio acid. Tht^e bacilli occur, for example, 
in deeayiug ehoesie, and eHTinot live in a Holntion of lactic acid of 
more than a certain concentration; in order to make fernientAtiou 

eon, chalk ifl added, which neulralizcN thtt lactic acid formed. 

!<actio acid can aUo be prcimrL'd by heating glaooee or iuvcri- 
augar with catustic sodiL 




9>0 



OnCANIC CHEMISTRY. 



Lftctio arid deriTns itn name from it« prosenoe in Bonr milk, 
ae a result of the fflrnientaUnn of the inilk-nigar present. Tbe 
faint aci<I odour poseeseed by 8onr milk is due, not to lactic acid» 
but to tnicea of voluLile fuLLy HoitU gimullaneoiigly (ortned; lactic 
acid iut'U is odonrlusn. Ijit-tio aL-id iilwt occur* in otWr fcrmi'nled 
eiibatiLUL-i'K. <iud] utf Snufrkrmit. Aud in largo (jiiuiititios in ensilage, 
lined for feeding cattle, wliieh is prejuired by sulimitting pUcs oi\ 
^rufix, ctovfT, etc, to pressure. 

lactic acid is puriticd by distQlinf; tho ftqu«ous acid at rcry 
low pressures (1 mm.), when it is obtained as a cryirtallino 
solid molting at 1)4^. It iei moro umially met with in the form of 
A colonrleiui, iiynipy liquid nf strongly iu>id tuiiti>, and containing 
water. When heated under ordinary pn'ssure, with the object 
of removing watnr, it is partially converted into tho anhydride 
(183) even before compli^tc debydnUiun liats tuken place; this can 
be detected by the diminution of the 8cid-e<|uivnlent on titration. 
It« zino Halt forms wcU-deQned cryittala with throe nioloculos of 
water. 

The cuQuCilution of loctii^ a^id is deduced from its formation 
from, tmetaldc-hydo by the eyanhydrin itynthesis (182, 5), and by 
the ozidotioiL of propyleueglycol. When bw-'tic acid is heated, 
atone, or with dilntc sulphuric acid, it splits up into aoetaldehyde 
aud foruio M^d: 



CH,-CHQ| irC00lI | -. CU.'Cg +11C00H. 

This deoompowtion may be looked upon as a reversal of the 
cyniiliydrin HyniheHis, and is eliuracteriHtin of many ur-hydroxy- 
acida. 

n 

lActic ucid, (!II,-U<C001I, contains one aHymmetric rarbon 

atom. In occordancu with tho principles laid down in 63, itoaghfc 

to exist in three isomeric nioditioations; all of theao arc knowu. 
Ordinary lactic ucid, obt^iiued by syntbema ur fermontation, ig 
racemie; that is to say, it coasiiils of equal (|uantitlus of the dexiro- 
itotd and Isvo-acid, and is therefore optically inactive. The 
dextro-lacticand liL>vu>laclii; ucide can be vbtoiued from the inactive 
modification by methods described in 196. Tlie dextro-rotatory 



STF.REOIS0MEHSSM OF THE LACTIC ACIDS. 



231 



TArietj U B cgn8titn«nt of mcst-juicee, and is therefore soinetiinM 
callw] sarcolndic aciil. 

186. Ifc tuu just heen etatcd that RyntheRis ytol(l« inactive 
Uctic kcid. It in araully not poaniblo to preparo optically active 
pT«dllct« from inactive subetancee by wholly clicniiral moana. 
Since the inactive niodi&cation conBisis of cqnal pnrtK of ilextro- 
rotatory and lievo'rotatory subetnnco, both of the«e must b« 
formed in erjiial qnantlties in the syntheHtK. Tho question arises, 
»hy this 16 80, and an insight into the phenomcuoa is afforded 
by a consideration of the following examples. 

The nitrilo of lactic acid is obtained by the aililition of hydro- 
cyanic acid to ncotaldi'bydc (188, 5), the structuTsl formula of 
which is represented in Fig. 53: 



CH, 



CH, 



CL d 



Pio. ca. 

At-KTALOICnVtlC. 



oni 



or 



H 



OH 



CH 



H 




CN 



Fio. Si. 

LlCTOHmULB. 



on 

Fig. 8V 
LAciosrrntLB 



The addition of U-CN can tako place in two way«; theoxygen, 
which 18 doubly linki><l to the (■(•ntral carbnn atom of the figure, 
becomes Revered either from the bond e, oi d. In tho first cusp, 
the group CN becomes linked toe (Fig. 54), and a hydroxyl- 
group is Formed at d\ in the second oa«c tbi« is rcverited (Kig. 55). 
The configurations thus obtainod are mirror-images of each other, 
and cannot be made to coincide, they represent asymmetTic 
C-atome. 

The possibility of the formation of both active components in 
thus evident, and that thetto mimt bu formed in equal amounts is 
seen by a consideration of the probalnlliy of their funuatioti. This 
is alike for both, since d and e occupy simitar positions with 
respect to n and b, and Ihern is therefore no tendency for the 
oxygen to ri^main linked to the one more than to the other. 

In the example just given, an asii'mmetrit; carbon at»m has 
lesolted from an M<f(ji^i«»- reaction. The following Ir an example 
of tho formation, by suietUution, of a compound containing Mich 



««z 



ORGANIC CHEMISTRY. 



an atom. «-l>romopropionio acul, ii>^<no&H' '*" ** *>b^'"^' 

from |)n>pionic acid, ju>^<coit[i' By i*plftc«m«ut of He and 

ltd resptfclivel;, two acids of opposite rotation are produood, the 
probabithj of tlie formation of one beiu^ equal to that of the 
formnlinii of the otiit-r. 

C*i III pounds coiitaiiitiig an 'asymmctrio carbon atom can aho 
result from the aplitting-off of a group, aa In the formation of 

("•LI T.I 

meihylctfaylacotic acidi /< i? ^^^poOH' ^^ methylethyl- 

e 

malonift acid, ^^f >^<(:ooir' ^^ ^^^ °^ ^^'- "^^^ probability 

d 

that this will take place at e and at d U eijuat, so that an inactire , 
mixtart! is producvi]. 

When optically active lat-tin ncids, and optically active snb- 
stanccH in gcnoml, are strongly heuted, they arc convened into the 
opticiJIy inartivo modiliuitifln, containing ojiial pn>purtions of tlie 
dextro-modi&cation and Iiovo-iuodification. This necoeeitates the 
conversion of one-half of the optically aetive aubstance into its 
optiud ieoroer, it being eiifReieiit that two of the grAups or atoms 
liiikt'd to the asymmi'trie C-iitoiii ehoiiid change pliiceB. In order to 
convert Fig. 56 into Us mirror- image, Fig. BY, it m only t^seutial. 
for tixumple, for B aud !> to exchange poBitions. Thia can only 





Km. 30. 



Kio. 5!. 



happen throngh a breaking of the bonds between B and D and the 
carton atom, for a period liowever brief, followed by a reunion, 
either, a» nt firat, B to b and I) to //, or in tlm reverse order, 
D to i and B to d. In couw<iuence of the aiinilurity of the poM-' 
tions occupied by b and d with rotpwt to u and c, the probability 



HYURjICRYUC AaOAND LACTONES. 



221 



of the union of B with h and D with tl Is vqiial to that of the uDina 
of n with b and B with d. As i\ result of tliis. doxtro-rolatory and 
Isvo-rotntory molecule* ore formed iu equal numbers, eo thut after 
heating, th« Riibstancc \» oplicnlly inactive. 

OptfcAl iDMUrity i« namntxmo* dweloped without thd kid of butt. 
Waldem found that, tliu dexcrD-rDtulory iaobutjrl c£t«r of l)romupn> 
pionic a<i\i\, C'Hi'Cimr-COOL'tUi, and eoine other oompoundsconlAin- 
in)[ a Bi'siCoEu ill uciioii with iia lusjiuniutric 0-aroin, bucmuo uptionlly 
inncUra through being liopt forthrtwor faiir years at ttioonliimr)' tvni> 
peratua'. The volocity of tmiisformniion at ordinary tompciutiiras. 
for most EubBtauo(>s tuu small ta b« apfireciablo after (he lapHu of nvoii 
toDg pnriodii— «»d only iiieaaii mbla m hiijlier teni[)er&turcR, «bi«h 
liave an iicciTlftrntitig etTect upon most roaotions — has in these oases a 
mcnsurablo valuer 

1S7. fi'liydrorypropionic acid, or hydmerj/lic aeid, lias the formula 
CUiOU-C'Ht'COOH, and iita typv ot ihe y:f-bydi-oxy-noids. It can bo 
sytitbM'lii>c] from «iltiylt$ne by the oddilion of bj-pochloroiui acid, UOCI, 
trealmcDt of ttic additioD>product witLi potoaaium cyauide, and 
bydroiysiii ut tin* mulling nitrtl*: 

cn,:rH,-.<m,oH.rH,t!i -^ cH.oiinr.cN -> cn.on-OH.txjoH. 

Ettayktwi al/oolclilorlirilriu Ol^ixilojruilijdrln B-Hjilriiiii'propiaitic 

This oompound can also he ohtAtned from |0-iodopropianio acid. It 
baa ft nynipy conniatency, and chiefly differs from a-hydroxypropionio 
ncid in being (lc>com posed on beating, wllbloaiof water and fortnaCioa. 
of acrylic acid (IM). 

Aldol (llSi in cimvorkd by oxidatian into fihydrtiTf/hutyrtc acid, 
CHcCUOH-t'Ui'COOII, reliidi ousily loat-a wbIlt, fonniiig crotonio 
acid. Tba conatiiuiion of jd-hyilruxybiityHc acid follows from its 
formation by the reduction of ilie corresponding Icctouic ncid, ncoto- 
•eetic aciii (SSBj. 

LHtonei. 

188. It was mentioued (178 And 183) that the ^'-hydroxy- 
■cide low water very readily, with formation of liiPtone«. So ^Twit 
is this leiidi'iiLy tliat aoiiie ^'-kyilroxy-aoidti, whon sot fr«« from 
tbeir salts, at oncu tipltt off one molecule of water, jieMing a 
laetoiif. Tliis phniomeiion \« another example of the readineu 
with which riug-compoHnds containing four carbon atoms are 
forroed (169). In many cases the ^'-hydroxy-aeidH aro not known 
in tho free state, but only in the form of esters, milts, or amidos. 
The lactones aru stable towards an atfueous solution of sodium 



*u 



ORG Attic CHEMISTRY. 



curbonHt«, hut are uouvert«<l by the hjdroxideit of the alluili-metals 
into saltd of ^'•hydroxy-iurida; this rcuction proves their cou9tiTu< 
tion, Thcyouiy bo loukod npuu lui tbv innor c«t«rK of the hjdroij'* 
acids. 

The lactoutw van be {trepared byeeveral rnethuds. Thiu, icidi 
containing a duubk- boud Mt the fiy- or j-d-jiotiitmii are readily coii- 
Tert«d into lactoues by warming with dilute enlphuric acid. The 
formation of lactunut in tbia wuy nmj be lookvd upon as BD addi- 
tion of the curboxyl-group tA thu doublu bond: 

H-(fH:dHCH,-00 = R-0HCH,-OH,CO. 
hA ! '. A 

Unsaturated acids J^ (llO><!an be obtained by several molhods. 
ODD bflitig the AOtion of aldelifdoa upon M»iiiiin Bucdnate in presence 
of aoetiv anhyrfrtde : 



,.H 



,Mt 



'""|i)MX>0;Hi. 



CU,.CJJ + HjCCOOH _ CH.ClIUC.COOH 

By olimiiialiou of ouu molecule of water, lUftre reaulta a laototw-aotd, 
CH.CHCH CO,H ^ 

O— CO 

wblclt, on dry dialillAtlon, loaes CO*, yielding Ilie unsaturated aoid:. 

CH»-CH.CH.|tA|ir 

CH, -» OH,-CH-CRCH,COOn. 



6 



-lo 



Another method for the preparation of lactonea in the redaction 
of y-ketoniu tuAAn, the synthesis of whtoh will be deiieribcd Ut«i'. 
($>and c-lactoneH Hrc also known. 

On boiling with water, the Inctoiies are partly converted into 
the correspond iog hydroxyacids: the quantity of acid formed is 
in part dependent npon the amount of water present. A state of 
etiuilibrium is arrived at betw^n the acid, and the Lictone 4- 
water: 



CH.OH CH, 



cn.-cooii 



r-Hjdrozrbutxrio «itd 



CH,-CU,CH,CO + H,0. 

I i 

BuljrruWclonF 



UCTOHES. 



»5 



If the molecular concentration per litre of the y-hydroiybntyric 
avid is A, and if, after tlio Ispeo of a time ^ x moloeules havi>i bocn 
converted into luctoue, the velocity of lactoue-forniatioti iLt tliat 
inetant, j*, is givou by the following eqiintiou, in which it is tha 
nmvtioii i-onataiit: 

» = k{A — a:). 

Bnt the reverse also takes plarp, the acid being rogeneratcd from 
the lactone and water. If the lai^tone is diwiolv'ed in a Urge exceiu 
of water, no u|)pn;(- initio error, in introduced by aiwuming the 
qnantit J of thi> latter tu bi- constant. Tlio velocity s' of this rBrcrso 
reaction is then rr^prceentcd by the equation 

in which C ia again the reaction oonetaut. The total velocity of 
the lactone- fo mat ion for etRli instant \&, tberoforo, oqual to the 
difference between thege volooitiea: 



g — a' ~ -fT = ^(A — z) — k'x 



(I) 



When eqailibriuiii is reacliud, n = s'; and if the value otx ai this 
|h>int boa become equal to jc, . then 



k(A - X,) - X-'x, = 0, 



or 



= — IL 



Wa^ 



(a) 



Eqnstione 1 and S can be solved for k and k'. The same 
method of calculation may be Hpplied to eiiter-fomiation from acid 
and alcohol, by which tlic reaction (constant ot the catur-fomiatiou, 
nnd of the cster-dt'c^mpodition, can tic computed. 

ITio lactoncB form addition-producta witli hydrobromic acid as 
wen as with water, yielding ^'-bromo-acida, the oonetitntion of 
which follows from their reconversion into hietone (I7B). Tho 
lactones also fomi ailrlition>productii with ammonia, yielding the 
amides of the ;'-hydroxy-acids. 

m. DIBASIC HTDB0XT-ACID8, 

1I9- The umpleat member of this series is tartrontc 
COOlI'CHOnCOOII. It cnii buobiaiaed by the action of moSstozlde^ 
nf illver upon brotnoRia.Ioina acid, and ia a cryslalline solid, melliog at 
IW with evoliilion wf 00,, Tlie glyoolUc wld. CH,OHfOOH. thus 
formed, at ouc« 1os«h water, yielding a pGlynivr of glyoollide (164). 



936 



OkCANiC CHEMISTRY. 



190. A Biibstanee of greatur importance in malic arid, C.H^Oj, 
which U preeeot lu various uuriiH! fniits. anil U beat preiiarud from 
unripe roountaiD-Mih berried. It is u rrj-fitalliue soliil. melting al 
100°, and la rcadll; solnblt} in u'uter »nd in alcohol. Natural 
malic acid ie optically actirtr. 

It is poeeiblo to prov« iu aovoiul vajn that malic acid is 
hydroxyanccinic aoid, COOil-CHOH.OK.-COOH. Among thw 
are it« rednntion t^ succrinic aoid hy hunting with hydrjodio ncid, 
and itd convention into mnnoohlomtvucrinic acid by the aotion of 
phosphciruti pcnbachloride, etc. Its alcoholic character is indicated 
by tht> forniutiou uf uu ocotatfi when its diethyl eetur is treated ' 
with Hcctyl chloride. 

The formation of fumaric and maJoic acids from malic acid 
under the influence of hcuvt ha» been alnmdy mentioned (170). Ln 
addition to tho natunU Imvo-rotatory ncid, beth n doxtro-rotaiory 
and an inactive modification are known. The latter can be split 
np, by fractionftl rrvKtallixittioi] of \\s cinchonine a«Jt, into iis ta'O 
optically artive components. As eoeti from its tttructural formula, 
malic acid contains an aeTmmetric C-atom. 



Tartaric Acids. (',11,0,. 

191. Four acids of this compoailion are known; all have the 
constUutiona] formula 

COOH.CHOH-CHOH-COOH. 

Ihtj are called dtxtro-rotiUvry tartaric acid, Imvo-rolatory tar- 
taric aci4, racemic acid, and invsotartaric acid; the last two are 
optifstlly inactive. Their mnstitutiou is proved by their formation 
from the dibruraoHUccinJc acids — obtained froDi fiimaric or ma]*'ic 
acids by the action of bromiuei — by boiling their silver salts with 
water, as w«ll us by their production from glyoxal by the cyitn- 
hydrin uynthcsis. Tho inactive modifications are produced by the^ 
rc<actione (186>. 

In a<'cordnnce with the conRtitutional formula given above, the 
tartaric aeidH ooutnin two asymmetric C-atoms in tlit* molecule, 
and it is neceswry to consider how many sterooisomurs are Iheo- 
rcticnlly possible. 

The formnla nf a Hub«Um-c of tlm kind may be rcprcMlited by 
C{ahe) — C((/r/). The groups linked to the wymmotrio C-atoms are 



STEREOISOMERISM OF THE TARTARIC ACIDS. 



337 



I 



in this g«Qcra] foruiiila dieeimiUr; the two symmetric C-Atoms 
are aunniocl to b« unlike. Hiucv the modo of nrrangemcnt of the 
groups relfttiTo to etwh at these C-alonifi rBuuItu iu duxtro-Totation 
and lasro-rotAtiou reiipBftivvlT, the following t-ombiuatioiis are 
powiblo ia tlw molecule of u mlutiuicu cvntniuiu^ two uymmeiric 
C-atoms: 



C(abc) 


1 

Dextro 


8 

Dextro 


3 

L»TD 


1 

Lsevo 


Dextro 


Laaro 


L»TO 


Uexir 



I 

I 



There arp, thereforp, four isomers possihle, njiart from t,!io optically 
inactive modifications containing etjnal ({UHtititip» of two of theM 
(1 and 3, t and 4). 

Since tartario acid, howovcr. contiiiiis two similar asymiiit-tric 
0<AtoiDi, that is to eay, asymiautric C'-utoma in uniuu with eiuiiiar 
groups, 'i and 4 become identical, Icoving so fur three isomers po«- 
gible. I and '^ hnnj^ nbln to unite, to form a racomic compoand, 

total numl>er of poRsibto isomer? is raib«d lo four: 



■ 12 3 4 

■ CH(OU)(COOH) Dextro Dextro h«..o i^tivo combin*. 

I 



:H(0H)(C00U) Doxtni laTo Lievo 



tion of 1 and 3 



The four acids. C^H^O,, mentioned above, correspond in thoir 
properties to tho four theoretically possible isomers. Dextro- 
tartaric and Isvo-tartaric a<'id» muttt )>« rc>]iri>Bc»nted respectively 
by 1 and 3, ^nco in theiw botli OatomB rotate the plane of polar- 
ization in Lbe same dir«L'tion. and should, theri'fort?, reinforce 
ODcaajthcr'tt mlluencc. The optically itiuctivc nicKolunuric acid, 
vbow two oppositely rotatory C'-utoma ncutroJize i>acli other, is 
reiire«ented by 3. Finally, the ieonior '1 it racuinic acid. 

An important dilTcrerii^e osi»t8 betwcon the two optically inactire 
isomers, nicemic and mpsotartarie acid. The former, obtained by 
mixing equal quantitlps of tho dpstro-aoid and lievo-arid, oar be 
split up inl4j iU vomponcntH ; the hitter, coniiiaLing only of one 
kind of molecuW, cannot bo split up. The rotation caused by 




»8 



ORGAffK CHEMISTRY. 



the dextro-acid is equal in nmount bnt oppoaite in sigu to thot 

caneed by the laevo-acid. 

£mil Fischer hae introduced a simpio mode of irritin; the 

spaciiil formula) of optically active oompounila, of which frequent 

UBo will be made hiter. Hie repneseutatiou in upactr of two C-atoins 

Cnic 
in uaion^ in % oomponiul | , j» shown in Vig 58 (169). 





Fio.». 



If the two bonds uniting tho two carboa atoms arc supposed to 
lie in the plane of the paper, then the poaitiona of a and c are to 
the buck, and of & to the front. If a, h, and c are iinBj;;ined to be 
^ojected ujion tlie plane of the pajior. and a and c iiiuiullaneously^ 
80 altered in positimi thai ihcy lie iu theeume straight line at 
right aaglos to the vertical axis, and b Uoh in Um axis produced, 
then projctition-lifTurc I is obtained : 













A 


f" 


f 






1 


1 


• 




1 


1 






I 




] 


L 





If Fig. 68 ia rotated round iU rortioal axis, so that a, for uxniople, 
]te« in fi'nnt of the (ibne of the pap«r. Fig. S9 \i obtained, tlio pro)i 
tioa vf which U repras«nte<l by II. Tti6»e appareiHl^ difforeat ooo-] 
flgaratioiiK Ki« identical. 



STEREOISOMERISM OF THE TARTARIC ACIDS. 



929 



For a chain of several carbon atoms, 6.g., four, there is 
obtained in an analogoae way the projection-fignre 



This will be anderstood it it is imagined that the figures on p. 200 
(Fig. 33) are bo placed that the plane in which the carbon bonds 
lie is at right angles to that of the paper, and the fignres in this 
poBitiou are projected in the manner jnat described. 

The projection-formulee for the fonr isomeric tartaric acids are 
obtained in the following way. If the projection-figure for two 
asymmetric C-atoma 19 divided in the middle of the vertical line, 
and the npper half of the figure rotated through 180° in the 
plane of the paper, the similar grouping of HO, H, and COOH 
about the asymmetric C-atoms in both halves. 



HO- 



-H and HO- 



COOH 



-H, 



COOH 



indicates that both C-atoms rotate the plane of polarization in the 
same direction. We shall arbitrarily assume that this grouping 
occasions dextro-rotation. 

When the two carbon atoms again become united with one 
another, by transposing one of the halves in the plane of the paper, 
the following figure results, and is therefore the projection*formula 
for the dextro-rotatory acid : 

COOH 



H- 
HO- 



-OH 
-H 



COOH 



a JO 



oRCAnrcr ^hbmistry. 



Tile grouping 'ff'rtVv tcK^iecfc to tho two C-atomg in the l»vo- 
routory acid niMfii b© the mirror- image of that iu the d«xtro- 
rotulory ^&3); tba». 



H- 



-OH and 



H- 



-OU 



i. 



COOH COOH 

Tho combination of these two gives tho following projection- 
formula for thv leero- rotatory acid; 

COOU 



H- 



-H 
-OH 



coon 

Thoso roprcsontatione of tho couetitiiLiona of dextro-tartario 
and Ifevo-tartanc Acid cannot be made to coincide by altering their 
position in the plane of the paper,* and are therefore difft'reut. 

When tho acid contain!) a dextro-rotatory and a laevo-rotatory 
C-atom, us in meaotartaric acid, th« arrangement of tiie groups 

Ooxtrv Ubto 



HO- 



H 



U 



COOH 
and theii projection -formala 

HO- 



OH. 



COOH 



HO 



COOH 

-n 
II 



COOH 



" TliMin pnijrrlion.fonuula can bo nude lo colncidp l>y lolulii^ oqb of lliom 
tlirongb 180* about Ihn lln<a HU— H. It will be Miun from a model, bowevsr, 
ibnt tlio tp<v:iai forcuulit- cnnnot be tnxAv to coincide \iy tliis tieatinont. To 
dvunninc wbetlior tUiii ii potuiblv for xjiitdal fonuuiw bv meuia of projeclioa- 
formultP, kt is only kdmlsflitila to tnnspOM llm latuir in lb« plkiie ot ibe papsr. 



DEXTROTylKTARiC MCJD. 



33> 



Tli« projoctioii'fonnula. for r&ceinic acid is 

Dfxtro Lkto 

tOOU COOK 



H- 
HO- 



ou 



-H 



+ 



HO- 
H- 



COOU 



-U 
■OH 



COOH 



Sextro-tartarie Acid. 

192. The acid poinsshitu salt, t\UjO,K, is prcaent in the jnioa 
f)f grupea, and duriug alcoliolic fermeutation is deposited on th« 
bottflm oJ the wiBkH, being ©veu more (sparingly soluble in dilute 
alcohol than in water. The crude product is t-'aHed "argol"; when 
pnrified, it is kuowu as "cream of tartar." To obtftlu dwxtro- 
tarturlc acid, the criidu argol is boiled with hydrochloric acid, and 
tli« acid precipitated as calcium tartrate, CaCJl^O,, with milk of 
linn?. After ■washing, the calcium salt is treated vith an equi- 
valent quantity of aulphtiric acid, whieli precipitatua culcjum aul- 
phate, and sets free the tartaric acid; this can bo obtained by 
evaporation in tlie form of large, tranBpurent crystals, free 
from water of crjTBtallization, and having the compoftition 

C.H.O.. 

Doxtro-tartaric acid melts at 170*, is very readily soluble in 

water, to a less extent in alcohol, and is iuaoltiblo in ether. When 
heated above its melting-point umlor atmospheric pressure, it 
loses water and yields various anhydrides, according to the intensity 
and duTation of the heating. On heating further, it tnrns brown, 
with production of a caramel-tike odour, and at a etill higher tem- 
perature, chars, with iormation of pjroracemic and pyrotartarie 
acids. It cuu be converted into succinic acid by the action of 
certain bacteria. 

Iq addition to the acid potassium, salt may be mentioned the 
neutral polttsf turn siilf, t',H,0,K,, which is readily soluble in water, 
»xi(lpOt(UsiHm antirMnyl tartrate, 

3[CooK.ciion.cnoTicoo{SbO)] + n,o. 

On BCconnt of ita medicinal properties, the latter is known as " tar- 
tar emetic." It is obtained by boiling acid potaSGinm tartrate with 
tuitimony oxide and water, aud iii readily Ruhible in water. 



«3> 



ORCANtC CHEMiSTKY. 



The prooipitation of Iivdroxidrji from mctallie nlto — evpiwr 

h5^m3Li<Ic from oopjier Rulplkute, fur L>xanipl<?>— is often ]>rovoDted 
(161) bjr thv pretieucc of turtahc uoid. Tht< ItcjUid obtuined bydis- 
iiDlviiiK cu|)pvr sulphate, tArlAnc aciil. and uxci-m of caustic: {lotash 
ill iviitt-r. ie callod " Fohling'saolution.'' It '\n au important meaiid 
of t^ittinf; the rcdmnng power of corapouudti, sinoc nwlucinfr-ageiitfl 
imvipitiite yellow inli- rod ciiproua oxide, or its hydroxide, from the 
ilirk-bhiB solution. In thin alkaliutt copper Molutiou the hydronyl- 
j{n>ii[M uf tho c«utral C-atoms hmve reactud with the rop^>er 
hydroxide, siuoo onf grsmme-moleciile of ueutnil tilkuli tartrate 
cun dissolve one grammo- molecule of copper hydroxido. These 
copjier alkali tartratofl hare nlso been oblsiiiod in a er|*ata]Iiiie 
form; for example, tho compound C,H,0,>ia,C'u -^ 211,0 is known, 
Kud to it must therefore be wKiigu»(l the cooBtitntional formnhi 

^^O.CH.COONa + '"'°- 

In aquentia solution this oompound U ionized Into Na', and the 
0-CH-COO' 
eomplex anion ^"^o.^h-coo" ''''''* ** "howa by the following 

faets. First, ths saliilion no longer givu« the ordinary reaciiona fur 
eopper ions; xlDiough ttie liquid Is alkntlne, cop|)vr hyilroxtde i& nol 
precipitated. Second, when tbo solution is olvctrolftcd, tlie copper 
g(M<K iiwarda tlK anode. This lias been prot-»d by K^ms by the at'l 
of tbe nppnniUis slioWD in Fig. 00, Uuo U-tube CDObtins copper sa>- 




Pl0. M.-'Ki.nn-aoi.raTe or ax ALKALtHS CorriR SoumoH. 



.^hate aolatioo at h ; the other, Fefaltng's eolation at <ii into both limba 
of «Moh it then CMrefully pourMl asotolioaof M)dioiB*alplute.aaade. 
The ooanoo surfiieea of tbe »odiutn nlphato and ee^per nlpbato 
Bolatlon* in the two U<tulM« lie Id Um sanw boriMatal pUitaL Vben 
•n eleotno earrwiit it paued through tlte tabm, peefeniblj' arranged in 
parallel, and twt iu seneSt a differant rffecl is prodnced on the poti- 



L^I^O-TMRTARiC ANO RACEMJC ACIDS. 



'S3 



tfoD of IIjO surrACi-s or the copper Aolutiona ia eacti tutc. lu lb« cop- j 
por sulphaio soluliou, a riee in level taken plAce at lite cathode, slnoof' 
tbe Ca-ioDft ar« cations, and teud towurda the atthodc. The rcvorsa 
effect b otjaerred in the Peliliii^'s solution, showiiig ibat here tbe cap* 
p«T forms \xkrt of th« anion, 

MocooTor, ttifl colour of Febling'a solution ia a raacb more iat«nM 
blue Ibaa tliat of a oop[Hvr sulphate solation of t^uivnlent concuntm- 
(lon, which iit <tvidfirtoe of the preaenca in Fnhlin^'s solution of a uom- 
pJcx ion eontaining copper, 

FebliDg'asulutJoii di-cuiD |>os«t on ataudlug, su (hat it ia beat pre- 
pared m required, lysr haa discovered a cnucb more stable nlkaliiiv 
copper BohitioD, wbich can be uaed for the aame parpoaeei as that of 
Peuuku. Tt ia a mixture of copper sulphate with acid and nvutrnt 
carb«OAt«« of potnasiiim, and uooiaina a aoloble double carttouate of 
e(^>per nnd potauium. 

LeTO-tartario Aoid. 
Lavo-tartarie aeid is obtainod from racemic acid. With the 
exception of their caueing opposite rotation, aud tbe fact that the 
salu formod by the l«evo-acid with tho optically actire alksloida 
differ in Hohibility from those derived from the deztro-add (196), 
the properties of the laevo-acid and ita ealta are identical with those 
of the dcztro-mod location and its salts. 

Bao«mio Aoid. 

193. It tuui tieen alrea<ly sUtod (186) that optically active aiib- 
etanoesiwri Iw converted by theuutiouof heat intoojiticjilly Inaotire 
ooinponiids; that is. (.rhangbd into a miituro of tlie destro-niodili- 
L-atiun and laivo-modiiicutioii in ii|ua[ propurlioiia. This clmngo 
is oftuu fiMiilitiited l>y the pr«8euce of cerlain substuuueii; thus 
dcxtro-tartaric aoid is easily converted into raccmio acid when 
boiled with excess of a concentrated solution of caustic soda. 
MefiOtartaric acid is formed at the same time (IM). 

The optical inactivity is occanionotl by convereiou uf one half < 
tlwdextro-acid iuto thu luivu-ujodiflcation. If rormuJa I ropressot 

COOH COOU 



HO- 



-OH 



HO- 



H- 



OOOH 



-a 



-OH 



COOU 
U. 



*4+ 



ORGANIC CHEMISTRY. 



tbc dvxtro-Bcid, then formula II will correstwiid vilh the Isro-ncM, 
and tUe furmtilw &bavr that the exchange of gnraps, liy nbiob an 
active compound i» cuart^rtiil into lis optical inomcr (111), must in 
this iostance take pince tit both luyramctrio C-atoma, in order tliat 
tbe dextro-acid inuy yield Its Iievo-iwimei'. 

iiacemie ucirfignotso soluble in water aathetwrtopticaltyantii-e 
acids, nnd dif!F(>ni in oryetfillinR form fruni them; the ctyHtalfli 
have the compontion tQ^lfi^ + 211,0. llany of iCa taltH contaii 
amounts of wuter of crystallization diffcnn); from those in the ssltll 
of UiB corrt-Bponditig optically aotivo isomera. Itnt'eiiiic Mid is I 
proved to consist of two compoucuts by its syotiidaiA from sola-' 
tions of tho doxtro-acid and the Irovo-ncid. If the eolations aro 
concoDtmtod, Itont \\i dov«lop>ed on mixing, and tho toes soluble 
racemic acid crystjillizos out. Itacemic acid mn also ho split up 
into the two optir^lly active modifications. 

Although racpniir^ acid iu the eolid state differs from hotli dextro- 
tartaric nc-id and Itoro-tartaric acid, j«t in solution, or as ester 
in the state of vapour, it socms only to bo a mixtnro of thom; at 
loost, the lowering of the freezing- point produced by it in dilute 
Bolntion corresimnilR to the molecular formula C,IT,0,, and the 
TRponr density of its ester to singlfl, instesid of to double, molecules. 

Thn term '* ruceniic*' i» applied to eubstunces whose optical 
inactivity \& occasioned by their cousistiug of iisomeni of equal and 
opposito rotatory power in cqni molecular proportiong. This 
phenomenon was tlrst obserred by Pahtkur in hia reseftrchu on 
laoentio acid (1S6). 

Meaotartaric Acid. 
194. Mtsotartttric acid, like racemic acid, is optically iuBctive, 
but cannot be split np into optically active componcDta. It Is 
formed when dextro-tartaric acid is boiled for several hours under 
a reflux-condenser with ii large excess of cauHtic soda (193). 

If formnla I ia a&signed to dextro-tartaric acid, it is evident 
COOIl COOII 



E- 



HO- 



-OH 

-a. 



HO- 



HO- 



COOH 

I. 



-H 



COOIl 

u. 



STEREOISOMERISM OF THE TARTARIC ACIDS. 



■0 

»35 



to convert it iato meaotartaric acid, formula II, it is only necessary 
for two gronps in anion with a single asymmetric C-atom to change 
places, while noeinio acid can only reenlt through exchange of the 



vH 




CO -OH 



-f-20H = 



CO«OH 




FiQ. SI.— UalbTc Acid. 



CO'OH H 



or 



COOH ^ 




COOH 



CO-OH 



H OH 

FiQ. S2. — MBeoTABTARic AciD, FiQ. 6S, — Mbsotabtario Acm, 



groups linked to both C-atoms. This affords an explauatioa of the 
fact that when dextro-tartario acid is heated with dilute hydrochloric 
acid, or boiled with dilute caustic soda, mesotartario acid is first 
formed, and raoemio acid only after prolonged heating. 

The acid pottusium salt of mesotartario acid is readily aolnble 
ill cold water, differing ia this way from the correq>onding salts 
of the other tartaric acids. 



aje 



ORGANIC CHEMISTRY. 



I9B. This view of the Btmotnre of the tartaric scids is in complete 
aooord with their relatioa to fninario and maldia acid (ITO), which, 
on treatment with a dilnta aqueotu solatloa of potassinin permaa- 
ganate, yield Tespeotively raoenuo and mesotartario acid by adtUtion 



HOCO 




+a(OH),= 



CO-OH 



Fio. U. — FuMAsio Acid, 




H0'*«=Cl-5 ——^ 



HO-CO 



+ 



CX)'OH B.^^zz—&- 4^C0-OH 

OH 
FiQ. 65. — Racemic Acid. 




of two bydrozyI>{^nps. Addition of 20H to maleto acid may result 
from the breaking of the bond 1, 1' or 2, 2' in Fig. 61, with produc- 
tion of the coDflgurations represented in Figa. 62 and 83. The 
projection-formulas oorrroeponding to Figs. 83 and 63 are : 



S7f.REOiSOMERISM OF THE TARTARIC ACIDS. 
H OU 



»37 



HO- 



HO- 



-COOH II- 

aud 
-COOH U- 



k 
I. 



in 
II. 



-coon 

-COOH 



Theae apparently ililTeretit conflsurations arc ideoLioal, as maj bo 
fluU; seen by writing tha first in ati«lh«r vsy (p. 338) : 

on 



OOOH- 

OOOII- 



-H 
-U 



OK 

If the last projciotioTi-formtilA is rotak'il In Dm plA.na ot tho paper 
tbiou|i;U 160", it vrtU coiucitlti iritb 11. A coiD]>ariaon of tbU aob«m« 
with that in 194 shows it to ha the oonfiguratlon reprefleDting mcso- 
tartaric acid. It follows that adiittion of two liydroxyl-groups to 
nuUvIc acid produces only mesntarta.ric acid. 

A di9er«Qt n;»ull is oklaiued by addition of two OH-groups to 
fnmanc acid, as will ho accn from fig*. 64 and 69. 

By tlio breaking of the bonda 1, I', or S. S' by addition, two coo- 
Hgnrations are oblalnMl which cannot be maile to colaolde by rotation. 
This will bo better understood from the following pTojcciion-formula: 

COOH COOH 



HO- 



HO- 



-H 
-OOOH 



HO- 



H 
OH 



-H 
-OU 



OOU 

COOH 



COOH- 

a- 



-COOH 



B- 

uo- 



OH 



-OH 



COOH 



A oomparlHon of theso with thoeo on p. S9I shows that the former 
repiwent deittro-tartario iind tero-tarlartc acldn. 



nB 



ORGANIC CHEMtSTRY. 



Rftcemio Siibsteiio«s, and their 8ep*ratioa into Optically Actirt 

ConiCituftQCs. 

Ids. KxpRrienc6 lias shotrn that optically nctire iBoment 
rotating thu plane of polarization in oppneitt* dirocttons, displajJ 
no diffurfiaco in ttioir utbor pli^-sicul or in thtiir ebcmtcal propcr- 
tiw, Tbc; have tho same eolubilitf, boUiog-point, and melting- 
point; thoir B&ltg crystallizo with the nanio numbor of molonaleit of 
wiiter of cryrtallizatioii, etc. It follows that the separation of an 
optically inat^tire BnbNtance into its optically active components 
rannot he rlTe<;ted by the onliiinry mothoda, ainco tlieso arc bated 
on diffcrencos in pliysital pro|wrtiefl. 

Pasteur has put forward tlirco methods for effecting thia 
separation. ""I'hc flrat of tlioso depends upon tho fart that tho Kalta 
of raceniic acids sometimoe crystallize frnm solution in two forms, 
ouecorreBpondingtothedextro-salt, andoneto thelsevo-galt; tl 
may aiibsefinently bo mochanic-ally separated. Pasteur showui!' 
tliis for aodiiim ammonium racematn, C,H,0|,Xa,(NlIJ,-|- 211,0. 
VjIK 't IIoff proved later that cn,-8taU of the dcxtro-turtntto aQd 
Iffivo-tArtrate are only obtained from this eolution at temperatures 
bolow '^8", tlii»i boiiig the transition-point for thaM iaIU (" loor- 
ganic Chemistry." 70): 

2NaNH,C,H.0,-4U,O 7* C,H.0„N»,CNHJ,.3H,0 -f- 6H,0. 

Destro- -f IVTt>> N»-Nn,-tartrmM h'a NII,-rBceliul* 

Fig. 65 represonts the cryatal-forms of llio two turtratca, the 
difference between tbttm being duu to tlio po»itioii8 of tho pi 
a and b. Tho cryatal-lorms arc mirror -imagea of ouB anotheM 
and nannot b© made to coincide. 

pASTKUH'fl Kocoiid method of aoparation depends upon a differ- 
ence in solnbility of the daltt of the ujiticallr active acidii, when 
thoy contain an o])tically active base. So long as the buae with 
whick a doxtro-acid or a lB>To-acid id united is optically inactive, 
as in thv metallic eoltu, the iutcruul struuturc of the molocnli) 
remains unchangod; tho constitation of tho salt-moloouloe, like 
that of the froo acids, may he represented by con figuTntions which 
are the mirror^imageit of one anotiier. Rnt tbix is not so when 
the dextro-actd and the liero-acid liave united with an optically 
active (for example, a dextro-rotatory) baae; the configarations of 



SEPARATION OP ftACEMtC COMPOUNDS. 



I 



the ealt-molccules ar« thon no longer mirroT-image« of one another, 
uid identity of phygicsl pro])ertiF« must of nocessity coase. 

Kacemic ucid can in this vav he sepnrat«d by oioans of Ita 
iuchonine Bait, einco ctnchonine lipvo-tsrtrate is less soluble tlian 
the dcxtro-tartrat*, and rrystalliKos mit from eolutiou firal. 
Strychnine miiy lio advantageously ueod in the separation of lactic 
acid into ltd compononts, and other examples of the same kind 
might betiited. 

The conversion of optically active subetancoa into otbera whom 
oonfigii rat ions are no longer mirror-images of one another, can be 



u 




- 


T 




/ 








J 


/ 







Flo. 89.— CuvaTAi^yoBMB ov Tirie Bodidm Auuukiuu Tartiiatim. 

el«d in other wnyB; thus, in the case of acids, by the formation 
'iMer with an optically active alcohol. The velocity of estur- 
formation with an optically inactive alcohol must be the same for 
both uomers, on accoant of the perfectly aymmetrical structure of 
the esters formed; but with an optically active alcohol the two 
isomers ore not «8teriQ(>d ut tbe uame rate, aiuoe the compounds 
formed are no longer mirror-images of one another, M.\kckwald 
has shown that when ritceiiiio muiidelic acid (347, 3) is heated for 
^Kaae Lonr at 125^ with menthol (363). an active alcohol, the oon* 
^BBt«rified acid ta lievo-rotatory. 

^P Wliilst the aolnbility of optical IsomerB in an optically inactive 
lolvent is the aamo, it munt be different in an uptically active 
>lvent. For, it ib t-rideiit that the solubility of a compound de- 
euda on the coufigunitiou of it* molecules aa well aa on tlioae of 
the Rolvent, since, ou the one hand, thu aolubitily of isomL-rs it in 
sneral dissimilar, and, on tbe other, the same substance diuolves 
different aolventa in wholly different proportions. It is true 
that optically active Isomora have a perfeL'tly nimilar atniL-tare, but 
relation to an optically active solvent their ooufigurationa are 



140 



ORGANIC CHEMISTRY. 



different; so that they behave towardii it lUce ordtnaiy uoineK, 
and must, therefore, have different aolDbilitiea. Kippixo and 
Port: have proved this for mdium ammonium racemate bj frac> 
tionut crystallization fmm u oolation of dpstrosn, vhich is dextro- 
rotatory ; in the firet fnictions thi-y found n markod preponderance 
in the umount of the dcztro-rotatory salt. 

The third method of gppnnition doviuid by Pastbcb depends 
on thcACtion of mould -fungi {PenteiUium gluucwm), or of bacteria. 
Thna. when racemic lactic acid in very dilute solution is treaxe'i 
■with the Bariittis acuU lavoladici, after adiUtion of the necfsarr 
nutriment for the bacteria, tbo optically inactive solntion becomea 
IaeTo*rotatory, einc* only the dextro-rotatory acid is converted by 
the bacilli into other gnbetanecs. A dilate Bolutton of racemic 
acid, ioto which traces of the mould -fungiis Ptnicifttum glaurmit 
hare been introduced, becomes 1teTo>rotatonr, since the fnogas 
propagates itaelf with decomposition of the dextrO'rotatory acid. 

The ftecond and third methode of separation are alike In prin- 
ciple. During their growth, the bacteria and fungi develop sub- 
stances called oiuymea, which dt-compose eompounda in a way 
hithiirto unexplained. Those eoKymes are optically active; hence, 
a difference in their action on the optical isomers, annlogooe to that 
described above, is to be expected. 

197. When a raoemic aubstauc« is liquid or ^aseons, it con;iifitfi 
only of a mixture of the two iaomers; an example of this was 
cited in coiiueotiou with racemic acid iu solution, and iu the form 
of esivra (IM). If the substance is ciystalline, tbere are three 
poasibiUtiex. 

First, the individual crystals may be dextro-rotatory or leevo- 
rotutory, so that the two modiUcationa cau be mccbaDicttUy 
separated. This ia expressed by the statement that the racemic 
BubstaiKie ia a eonglomerafa of t}ie isomers. 

Si-cond, it may be a true eompouuA of iho dextro-modification 
and lajvo-moditicutiuu, a racemic compound, tlie formation of 
which may be compared tu that of a double nit, when a solution 
eontaiuiog two salts is allowed to cTTstallize under 06rt*in oondi- 
tiona. 

The third posuibility is also analogous to the crystallization of 
■alt*iQlutioii8, whereby crystals are sometimes obtained containing 
both salts, but iu proportioiu varyiuj; in different crystals. 



somPtimM liappoiisthnt the salb* rrj-stallizo together in all propor- 
tionR, hut UAtiiilly tht^ae vMt vary iitilj between cvrtsin limits. 
Tb(! simuitunoouB crystuUiuition of talta in this way given nne to 
thp su-colk-ii mixeil cri/nlah. When this oucure with opticnl 

tisomors, paudoroiemic mixed crygtala result. 
Which of tKee« throe kinds of erygtaU cryntallijie from n given 
lolntion or fnwd mnss of a rnceniip mibstance — a conglomflmie, a 
ructunic compiitiiiil, or pseutloracfmic mixed enp'stala — dt;penda 
upon the temperature at which the cr>'sUiI ligation takes place, and 
upon otlicr conditioiiii. An example of tins ban Ixmn already 
mcntion(?d, eodium ammonium raccmat*; when conccntrat«d above ' 
28^ tho racomate crystallines from the Bolution of this salt; hclow 
thig tcmperntiire a mixture of the individual tartrates — the con- 
^^j^wnerate — is ohtained. 

^ft Bjlkhuis RoozBBtiOx has indicated a general method of dislin* 
Hgnifiliing between thcvse three ohisaea of compounde. For a con- 
W glomerate, thic ia simple. A saturated solution is made ; it will be 
of neoeesity optically inactive, and aitunitcd alike for the deitro- 
rotatcry and for the lepTo-rotatory body. If now tho solid 
dejtro-com pound or lievo-com pound is added, and the mixtura 
shaken up» nothing fnrther will dissolve, since the liquid is already 

»aaturated with the two isomers; the amount of dissolved euh^uce 
it) etill the same, ami the solution remuine optically inactive. Oa 
the other hand, if a nicemic eompouitd was presout, although the 
BOluliou VC&8 saturated iu the firgt inetauce with resjiect lu this, it 
ii nueatnrnted wiili respect to the two optically active modiflca- 
BtJons; addition of the solid dextro-rotatory or lievo-rotatory sub- 
^htaurc would canae a change in the total quantity of aolid dissolved, 
Fttid the liquid would become optically active. The methods 
employed to detect pdeiidoraeemic mixed crystaU are sometimes 
l«ee Bioiple. 

IT. POLYBASIC HTDftOZY-AGIDS. 

168. Of these acida it will be sufficient to deecrilw the tribaaic 

^iirif acid, C,EI,0,, wbich is widely distribated in the vegetable 

icingdom, and in also found in cows' milk. It ia prepared from 

le jnleo of nuripe lemons, in which it is present to the extent of 

-7f. The tric&lcium salt of citric acid is easily soluble in cold 

Iter, but very slightly in boiling water; this property is made 

use of for its sepamtion from lemon jnice, the acid being obtained 




M* 



ORGMmc CHEMISTRY. 



in the froe stato bj the subacqacnt udditiun of sulpbaric acid. 
AnotliL-r ttx^hnicul methud for its prcpunitioD lU-peDdA upon the 
liwt tbut ccrtMa mould-fimgi {titromiji-Kt p/efferianuf and 
V. glaber) produce considerable quantities of citric acid from 
glucose or mgar. 

Citric acid can be obtained Byntbetically b; n method which 
proven its oonHtltntion. On oxidation, Byinmctriciil dichlorfaydrin, 
Cn,C10II0H-0II,CI (162). IB converted iato ajmmetrical di- 
chloroucctonc, CU,01-C0-01I,C1. Tho cya&bvdrio evntheeie con- 

on 

verta this into CH,C1-G^CH,C], vhich, on hydrolrsis, yields 

.OH 

tho hvdroxy-acid, CH,C1-C^CH,CL On treatment of this com- 

^COOH 
po^ind with potassium cranide, a dicyaaido is lormed, -vrhich is 
converted by hydrolysia into citric acid: 



Tycoon 

CH,CN 



CILCOOU 
(]. OH 

cH,'Coon 



The alcoholic character of citric acid ia indicuted by the reac- 
tion of its tricthyl ester with acetyl chloride, an acetyl -compound 
being formed. 

Citric acid forms well-doflned crystals containing one moleonle 
of vat«r of crygtaltizatioii, aud is readily soluble in water and 
alcohol. It loses its water of crystntlization at 130°, and meltti at 
153°. It is used in the manufacture of lemonade, and io calico- 
printing. 




T. A11IR0.A0IOB. 

199. Tho amino-Rcid* contain one or more amido-gronps in 
direct union with carbon. They are of phyxiological importuneo, 
since many of them result from the decomposition of atbumitu. 
and Home of them uUo occur in nature. They can be obtained 
synthet icully by the following methods. 

1. Uy the action of the tuilogcn-BQbstitntod fatty acids on 
■mmonin, n method nnalogoue to the formation of amines: 

H,y |]l-f-Cll H,CC0OH = H.N.CU, COOH-l-HCl. 



MMMO-ytanS. 



us 



3. Bj roducLioD of oximuB with sodium amftlgam: 
EC(NOH).COOH + 4H = R.CHNH,.CO0H+ H,0. 

TluB is, therefore, » method for coaverting Icetooic acida into 
amino-ftcida. 

3. a-Amiuo-acids are formed by tlio action of irmmonia upon 
the cyatihydriuK of aldebydes or ketones, aud aubeequont hydrolysis 
of the sitrile-group: 

H /H 



+ NH, 



Alftniiw nlirllc 



CH.CfNH. . 



Alsolnv 



The smino-ftcids pogsees two oppoeitc charnctera; they form 
uUCB with both acirU and hase^, and are tlierefore toth basic aud 
.Kidic at the name time. 

Replaccmert of the hydrogen of the amido-groiip by radiclea 
tyieldif araino-acida of a more complicated character. Thus, like 
lammriaia, with ttoid chlorides they yield an acid amide, in which 
one hydrogen atom of the aiuido-group lias been replaced: 

RC0CnnaHN-CH,C0OU = RCQKHCH.C0OH+HCl. 



I 



CorapoiindB of this kind are therefore both amino>acids and add 
amides. 

Amino-noids in whinh the hydrogen of the amido-gronp is 
replaced by alkyl ar« aUo kiiowu. They arc obtained by the action 
of amincB, instead of nmmoTiia, on the halogen-substjtutcd acids: 

(CU,),N| lTTn lU,C COOH = (CU,).N.CH,COOH + UCl. 

The nmino-ncids undergo mo«t of the (Iccompo^iCione oharac- 
terlstic of amines; thus, with nitrous acid they yield hydroxy- 
adda, just as the amincji yield iiJroholK. 

The same remnrkublc tUtfprcnre of properties, occa^oned by 
ttw poaitinii of the amido-groupB relutive to the carboxyl-groajis, 
ia displayed by the amino-acids, as has been dcacribed in 178 and 
183 in connection with thohalogon-Biibstituted acids and hydroxy- 
acids. The /r-amino^aeidx readily jiclr! anhydrides (acid amides) 




»44 



ORGANIC CHEMISTRY. 



hy the eliinination of two mulccu'ee of water from two molecules 
of Mid: 

CO OH llHNCn, ' ('0 — HNCH, 



The ^-amino-actdit easily split off ammonui, with fonnatioit of 
UDsaCuratMl acidK. In tliiH wu^, /J-aiumoprop ionic acid, obtained 
from «3-ioc]opropionic acid, is couverted on heating into acrjrlic 
aoid and ammonia: 

|NH^| CH,C:h| h1-C0QH = NH, + CH,:CHCO0H. 

Lilte the y-bydroxy-acids, the ^-amiuo-acida yield inner anhy- 
drideji; thoaa aubatances are called iadama on account of their 
similarity to the lactones: 



r 



Cn,'CH,CH,-CO 



CH -CEI -CH -co 



I _ 
NBH 



_l 
Oil 



= H,0 + I 
• NH- 



t-ADiluobuij'nc Mtd 



l^euuB ot i-«)>ilBobm;rfc mM 



The vslers of amiuo-acich can be obtaine<l in the nsiial way, by 
dissolving thR acids in absolute alcohol and treating this solution 
with hydrochloric-acid ga« (97). The salts of hydrochloric acid 
are the primarj' proiluote (e.g., HCI-NH,* CH,*CO,C,Hj, the 
hydrochloride of glycocoU eater), because the ainido-group in theee 
eaters has its usual basic properties. The cstt^ra themselTea are 
prepared from tltose salts by treating them in aqueous solution with 
a concentrated solation of potassium hydroxide at a low tempera- 
ture, and iniiDcdiatcly extracting the liquid with ether. BviL 
FiSUHKH has pro%'rtl that these eaters are very useful for thepuri6os- 
tion and Hepariitiim of Hmiiui-HciilH. Thiii in of great importance 
in the chemistry of protei'dH, which are split up into a seriex of 
these acids by the action of acids or of bases. 

IndiTidnal Vemhert. 

BOO. OlyfMoU, or aminnnf^tic ncid, Nn,.CH,.COOH, can be 
obuiued by boiling gine with dilute Hulpbnric acid or with bariam 
hydroxide; it owes its name to this method of formation, and toiti 
swcot taste (yAtifctJ!, sweet; KtiXAa, g\ue). It is aIao prepared front 






hippuric add, which i» present in the nrine at horeee. and may be 
lookeil upon us glj-c-ocoll in which one of tht hydrogen atoms ef 
the amida-group bus been replaced by benaoyl, 0,11,00; hippuric 
acid haa therefore the formula C.U, ' CO - Nil CH.COOU, and, lik« 
all acid amidea, when boiled with dilute acids, spills up with addi- 
tiuti of the «leiiicnta of w&t«r: 



C.H,CO[Nn CH, COOH = C.H, COOH + NH.CH, COOH. 

OH [H BmtalaMid Oiyooooll 

Hlppiiiic acid 

QlycocoU can be syntheticatly prepared by the action of 
ammonia on monochloroacetic acid. 

Olycocoll is a cpj'stallin© solid, and melts at 332" with decom- 
position; it is very rendily eolublv iu water, and insolnblo in 
abaolnte alcohol. Like many amtno-acide, it forme a well-crystaU 
lixed, blue copper ealt, soluble with difflcnlty Id water, and 
obtained by boiling copper c»rbonate with a eolution of glycocoll. 
[t cn'stallixes with one molecule of water of crystallisation, and 
has the forraoU (Nll.cn, COOj.Cu -f 11,0- 

Beta'ine, C,H,jNO, , ie a derivative of irimethylglycoooU; it is 
Wild in the juice of the sugar-beet, and aeeumulat4?8 in the 
'nu1a8««8 during the manufacture of sugar. It must be looked 
Upon aa an inner ammonium ealt, 



i 

u 



(CH,),N-CU,CO 

i'H Ah I 



siune it is synthetically obtained from Irimcthylamine by the action 
of monochloroacetic acid, with elimination of HCl: 



f 

mi 



(OH,),y + ci-cir,-coon = (cn,),Ncivco 

1 o 



ICl 



H 



,Tlits reaction is anuloguu« to the iotiiniction of aJkyl halides and 
LTliary amiuea, yiiilding the salts of the ammonium ba«e. 
BetaTne fonnis liirge crj-staJg with one molecule of water, which 
\U loeca at 100'-, nrwheu allowed to stand over sulphuric arid. On 
hnliog, it decompose*, with formation of trimethylamine. 

kMany tertiary amines can be converted into Bubsianccs with a 
lUtaUon unulogQU^toJ.hat of hetaino; that is, inner ealte of 



^ 



34^ 



ORCANtC CHEMISTRY. 



STDmODium baB««. Theac corapoandB have the i^nenU nunic 
betainea. 

Alanine, or a-aminopropionic ttoid, CH,'CH(KH,)'C001i. is 
Byntheticallj prepareil by the Hction of mnmonia on ff-chloru- 
propionii; acrid. 

Levoine, or a-aminoisobntylacetic acid, 

(CH.),CH CH, CH{NH,) OOOH, 
rpaulU iiilong with glyoocoll from thu docont position of ftlbnmitu ■<« 
the action of acids or alksliB, or by putrefnction. It ig «ynUicti- 
cally obtained from iHOvaleraldehyde-ammoniA by the action of 
hydrocjanic acid, nnd hydrolysis of the resulting nitrile: 

/^ 



\ 



(ciy,CH.cH,.o^ on + n cn 



lK)v«l«nt|[!a)ird»<iiiinonl« 

Ln»dn« 
Oxidation with man^aneei? dioxido and dUnte sulphuric acid cod- 
vertt) Ivucinu into eurboii dioxide, water, nnd valeronitrile: 



C.H, -P 
N 



H -l^tlHj = C.H,. CN -I- CO, + 2H,0. 
H,+ QO 



C,H, 



VHwCOMI, 
J^n.KcoOH • 



It is remarkable that in this oxidation a sabstance is obbiim'd 
wliich does not contain oxygen. The Icuciiie obtaiut-d from 
albuminfi in optically active; its formula uoiitaias an aaymmetrie 
carbon atom. 

Asparagim is often present in sprouting itcedo; to tbeexteutof 
SD-SO-t in dried lupine seeds. It may be looked upon as the 

amic nuid (163) of arainoBUCcintc acid, 

UQce on faydrolyBifl it i« converted into aminosnccinlc ucid 
{mparlic acid), COOH CHCNU,) CTT/COOH, whose stnict.m- t» 
inferred from its conversion into malic acid by treatmeoi with 
nitrous acid. Aspar&gine prepared from seeds is BOmetitnoi 
dextro-rotatory, but generally Isavo-rotatory. The former is sweet, 
tho latter tasteless. 

Homologoas with asparagine is glutamxne, which is also present 
in the aeed» of sprontini; plants. It j» tho amic acid of <r-amiiio- 
glutftric acid, COOU C1HKU.)CH, CU, COUH. 



LYSiSe. ORNITHINE. AND DIMZOACETIC ESTER. 



247 



Diiunino-ucide arc also obtsiued by the splitting up of proterds; 

thua, lifgitte, C,n|,N,0, is pruduvud by the action of u(?id« on 

olbumiue. PutrcfactiuD-bttuUli dccotnpoev it with formation of 

I jKDtomothylcnodifiniino (16S), and, us it U tm aoid, it is probable 

that it has the fonniil» NH,OH,-(CU,),.CU <^J^^jj, aud is an 

' ae-dianuDOcaprcic acid. 

Ornithine h the n<<?ct lower homologuo of lysine; it bai the 
JonnuU C,E„N,0, or N!f, -CH, CH, CH,- CHlNH,) -COOH; 
bj the action of biiuinriii it yield* putreeciito or tetnimethyleno- 
diamine (162). Its structure ia proved by Kail. Fischeb's 
ayntlicais (338). 

Diazoacetio Eit«T. 

flOl. 0iniTru9 faaa obtaioed » yollow oil of cliarHc-Cemtk odour bf 

tb« action of nitroiia acli) on Iho ethyl Ptttrr of glyMcoll; this mib- 

Btancfl fiiplndes on heatiug, and has tlio formula L'.IItNtOi. Tbc 

Dcchod of itA formation, and its oonstitntional formula, are indicated 

tbe following e<|unti«n: 

c,H.ooccn,.>ni, + nso, = cn.ooccnf n + 2ir,o. 

Olyonooll Mdr ^N 

|.ii called diazoQixtic (jter ; its constitution is inferred (ram the fact 

; Its two nitroKeu atoms are replaceable by two monovfllent (groups 

' elemenu: thuti, on heating wtCb water, it is converted Into tbe etbyl 

^«ator of glycollic acid; 



C,njOOCClI<^ 



+ 5ii = f,H,ooc-cn<gjj + N^ 



ta thia way it yields monocliloroaoeiic e«ter with bydrocldorlc acid 
■ad di-iodoaootiu enter with iodiuu. The hydrogen atom of tho 
CHNi'fcroup is replucuablc by niotala, medium diwolTing iu diazoaeetic 
teter with eyolutian of hydrogen. 




M atom, 

jCvaBKn.3u «ESM»4£«VMaanneHM?MiaBMC3L*aiL, 

tm- 'Mou^ -Mum. "auc -m jyaai ^ mc bcx. T^ aicrac : 
maiiaM. ndbuie jns« ':a<t«irBir^ ^w auMOOL jt attwrr \iJiLa a L . wj^ 
liiiii'iMi ifrjiiiii" i_7 iiMi Miif imTi w ifti iiiif ii'wi ii'i 

^jivsak. » » •nirtiBSeai. aHurTOMiB «i-iw»ii»: 
X fiMMCvvi 3ta^7 21 wKitr. 'ins t^tt UKwrj j&a- «iB3ueGe -c:7>af 
w vmtmt ic ^IV-lai*^, W -nwiTrifTTii'TTTn m -aiirnryw if iwcTii ii 

^fc ';ae aJuflrr-M*. «b*a. M toe f-^.^uKaw. -'.f % £:*>se tafrrx. Ox. 
3. MW.rt3£<% vf=2. TU KaoM 



H H 
O O 



= CB,OH-COOHl 



H. O 



MS 



D/f(£TOffES. 



»49 



DiketoQet. 

203. The dikelouea contain t-wo carbonyl-groupn, whose relative 
pogitiouB Jetermiue the methods of prppanitiuu uf thest coin- 
jiounds, and tlicir propertivB. 1 : 2-l>ikotonc-a arc kiiowu contain- 

IV 19 1 

ing the group —CO ■ CO—; 1 : 3-dikotoneg with —CO ■ CH, CO— ; 

l:4-diketone«with — CO-CH,CH/CO— ; and bo on. 

I : "t' Dikftoues cannot he obtained by tliB elimination of clilorine 
from the acid chlorides by the action of a metal. 



R ■ COlCl -l-Na, + CilOC ■ R, 



r a method which naturally Bnggraba iteclf. Their propiratton has 

I to be effected by the action o.f amy! nitrite and a little hydro- 

I c3iloric acid un a ketone, whereby oiie of Che CH, -groups La coa- 

I Tert«d into C=NOn. 

I Th 

i dUi 



E-CO-C 



U.J.R' 



HCO 



C-E' 
NOII 



These connpoundM arc called isonilrosoketoneii. When boiled with 
dilute sulphuric acid, the oximc-group is split off ae hydroxyl- 
amine, vith formation of the diketone. The iefoaldehydetf 
which are boOi kutouea and aldehydea, and contain the group 

— (-0-C^.., cui also 1)0 obtained by this method. 

Diaeeit/l, CH,-CO'COC"I!,, (tan bo preparfid from methylethyl- 
ketone in^the way d^Kcribed above. It is a yellow liquid with a 
punguut. sweetish odonr. and is Bolublo in water; its vapour liiia 
the Humc uotour ais uhlurinu. DiaceLyl buUs at 88% and lute a 
fpeoilic gravity of 0-BT3 at 30°. Ite behavionr is tliat of a sub- 
tctaneo conttuning two oarbonyl -groups; it adds ou aHCN, yit^lds a 
mono-oxime and a di-oxime, etc. The two carbouyl-groupg are 
■hown to be next to each other by the action of liydrogen perox- 
ide, wliich coDTerte it quantitatlTely into acetic acid : 



CW -CO— 
-h OH 



CO- on, 

OH 



aCH,COOH. 



»So 



0RG.4NK' CHEMISTRY. 



iiS'lh'lulouM can be prepared by a condenmtion-method di»> 
covered by Ct.aisek, whic^h w of general appUmtion. He 
employs sodium ethoxidr ae the cnndenBing'Sgent. un ttdilition- 
product Wing foitniid when thu ttubetunoo is brought into coutoct 
with an oetor: 






0(',H, 



= RC^OC,H,. 



This addition-product ib thun treated with a ketone R'-CO'CH,, 
whog« niothyl-group reacts in fniob a w»y ae to oliminat© two mole- 
culos of alcohol, with fommtion of u condenHutiou-product: 



n/l 



ONa 



^ '^\| o[-:h: + H CH.CO.R'=B.C^gy.co ■R^+aC.H,On. 



On treatment of this oonnpoond with a dilate acid, the godium 
atom w replaced by hydrogen. This might ba expected to produce 
a compound ('nntaining n hydrosyl-groiip in union with a donbly- 
linkr^l rarliim ntom: it liati b«4in alicudy mentioned (136) that 
compounds of this type aro as a rule unitAbto, the group 

Oil 
— C=CII — passing into — CO — CH, — . This mlo IioWb good in 

on 

the present iuBtancc. KtJ=Cli'CO- R' yielding a 1 :3-diketone, 
R CO— CU— CO it. 

Anottter ii]«thod for the preparation of l:8-diVeU)DC8 is the action 
of acid cli1ohde« on theeo<liUTn ooinpoandsof floetyl«in« bomologuee : 



CH,.<CTH,».r=rlS«+_CI|fK'.Cll.- 

SodlD-n-oia; lacctyltne Acctft cbloNde 



.CH..C0H0«'0aiC-OO.CH,. 



By treating lliia ketooo with oonceatratod Hulptiurio acid, water ta 
added oti, and the desited diketone obtained : 

0H,-(tJH,).-C=i;-CO-UH, = CH,.(CH,),-CO-CH,CO-Ca,. 
+ H, 

Thc«o diketonee have a, weak acidic character, their diMOcia- 
ticm constants, which hare been determined for some, tncludin| 
aceiyhcetow, CH, CO'CH,-CO -CH,, being very small. The? 
contain two ll-»toms replaceable by metalB — those of the methy. 



4 



DJKETONES AND HALOGEtTSUBSTllVTED ALDEHYC 

'huv-^Ttntyi lietweeij two negative earbonyl-groups; for If it were 
ithc otbvr favdrogeii utonm which (u>uld he. thim exch&ngHl for 
l-mctJilii, there ie uo rciuoii, since ihcy art oi i>qual valtic, vhy two, 
[and ouly two, aliouM bo rcpluucablc 

AtxlgJacetone is obtaiaod by t}ie coodeDAalion of ethj] acetate and 
acetone in the msnner described abovt-. It is a coloiirlesa liquid of 
aKrwable odour ; B.P. 187', bd. gr. OitT» al IS'. Wbou Iwilcd with 
water, it upliu ii}i into acetone and aeetio acid, tlds rvaction anordiiig. 
another example of the ioatabilitv of oompoiinds coutaining a carboa' 
aiocn loaded with n«t(Ktive g roupi. 

Aror>ng the xsiiia r-t occtylneetono may ht ncotioiwd the copper 
sail, (CtfliOOtCti. which is iipartrigly soluble in water: a»d the vola- 
tile aluminium salt, (C|HiO,)iA]. By n determination of th« vapour 
density of this compound. Cohu» has nhown that the alumiaium 
atom la triralent. Many of theae saha niw insoluble in water, bat 
soluble in benzene, clitoroforui. or other organic aolTenta; thia makn 
itdoublTal wbuthcr they Ar« truo salts. 

As « irpe of the I'.-i-tlikeloices may be cited acelonyUtcetoue, 

;H,CO-CH,-CU,-CO-Clt,, the preparation of which wiU bo 

fdeecribed later (236). It is s oolourtoBa liquid of agreeable odour; 

B.P. 193% ep. gr. 0-U70 at n". Acotouylacatone and other 

] : 4-diketonea yield a variety of eompoundg coutaiuiiLg a cloeed 

[chain, which «ill Ije treated of in 391-393. 




Halogen-iabstituted Aldehyder 

804. Chhral or trichloroacetaldehyde, CCI,- C^q, is of ^reat 

' importuiKW from a medical Btaitdpoint. With one molecule of 
iriit«r it forms a cryslallino coniponud, which i« used u a Boporilic 
under the mime chhral hydraif, and is teohnicslly prepared by 
Mtnrating ethyl aleohol with chlnrino. The alrobol must hv. aa 
free from water ait posHJble, and the chlorine mnflt he can>fully 
dried. At first tht reaction-mixture is artificially cooled, hut after 
a few days the process becomes leas energetic, and the tempoiature 
isdowly raisod to Oi)-, and finally to 100°. 

This reaction miiy bo explained by assuming that the alcohol JB 
firit oonvert«d into aldeimie, which is then transformed into 

tlKvtul, dichloToacetal. and trichloroscotal ; the Inst compound is 




^ -"r*c: — ■ x'-.l 



t- '»■...■-. 






■^ ..- . ^ .hi _^_ 



-rf; T^^,-, 






«.— * "SW »: : -^ -- ■-- 



« ■ j'i- 









.> * .'-4. . '.-r/ -.-. :'>^ ■ ti ~;,.i^,'~ "r'i '"^ "»." ;.~T! ■*",■_! Iirr 



CHLORAL AND HALOGEN-SUBSTITUTED KETONES. 253 

On account of ita parity, chloroform prepared in this manner is 
preferred for pharmaceutical QBe. 

The formation of obloroform from chloral by the action oC 
alkaltiie liquids suggested the use of chloral aa a soporific, it beio^ 
eipected that the alkaline constituents of the blood would decompose- 
it with the formation of chloroform, thus generating the latter in the 
body itself. Liebbkicb showed that chloral has in fact a soporific: 
action, but more recent investigation has proved this to be independ- 
ent of the formation of chloroform, since the chloral is eliminatedl 
from the system as a complicated derivative, urocbloralic acid. 

Halo^en'fnbstitiited Eetonei. 

S05. An example of this class of compounds, dichloroacetone, 
OH«Cl-CO-CKiCl, was mentioned in 198. Variously substituted 
ketones, some of which have a powerful odour, are obtained from 
acetone by direct ohlorinatioo. 



AISEHTSE ASD EEXONS ALCOHOLS OS 8TT0AS.8. 

206. The term ''engarft" fomifiriy includcii comi>ounJB con- 
tainiDg six, or a lunltiple of six, csr1>oii atoma, and hydrog«u and 
oxygen in 'the ]>roportioi)8 to form water. To this they owed th« 
iiiimc carbiihytlrates. Whvii boileil with dihiU" iiciiis, thp mignn 
cotitiimiiig a m»Uij)lo vt bU carbuu utoma Jetiomimst', taking op 
the elements of water, with formfttioa of carboliixlniles containing 
six carhou atoms : 

The Utter liad the general name monogatchariJei, w)ule those 
containing » X 6 ciirbuii utouis wero called polytatxharide*. 
Among the monosucchurideii were grupo-eugur, or glucom, and 
frait-Bflgiir, or fructose, both with the formula C,il„0,; the 
polvMicchiiridi'H ineltuliHl rnno-ttajmr niid milk-nugnr, with the 
formiiU C',,ir^O|,, ami sta.rfh and eellulnse, {C',II,|,Oj)x, of on- 
known molecular weight. 

]\Iiiiiy itinnoHiccliaridi!K containing six carbon atoms have been 
prepared since ISfiTi chiefly thruugh the n-searrhes nf Emil 
FiscnER, and ecveral new enceharidcs containing more or lc<s8 thitn 
Bis c«rbon Btom* have also been diseovprod. The conetitntion 
of most of tbese tM>mpOHiidK has been determined with great 
certainty, so that a new light has been thrown upon the chemistry 
of the sugars, and tiic definition of these subatanccR from a chemioU 
standpoint bae, therefore, undergone confliderablc modtScation. 

Tkt monoiocchari^ee ai-e aldehytle aleohole or teiortt aUxhclt 
containing ott« or more htjdroxyl-groupSf one of which in <iirectiy 
linireii to ti eoTbon tUovi m uttioii mth earhonyl. The characteriBtic 
gronp of t)ie*e compounda is therefore — CnOTI — CO — . 



NomeDclaturD and OentraL Fropertiei «f the llouoses and thair 

DerivatiTes. 

807. Tlie monoBtooIiandos have now the gcncrul namo monoits: 
when they are nldohydes they are culled aldoses, and when ket«n«8, 

354 



MONOSES. 



*55 



hioset. The number of carbon atoms in the molecuta is indicated 
b; their namcB: thne, pealose, kezose, heptwe, etc To denote 
vbetheT a compoand is an aldehyde or a ketone, tbe pretix«B 
"aldo-" and "keto-" respectively ar* oaed; as ald^kexosc, helo- 
fiBxcse, and so on. 

The polysaccharidee aro now called polynte'. When they may 
bo regarded as dL*rived from two monosu molecules by the elimiua- 
tioD of ono uiolcculo of water, they arc called Imaea; thna, htxa- 
,iioaes when they are formed from two molecules of hexoiie. The 
'polysaccharidcsderived from three monoae molecules by tb* elimina- 
tion of two moleculea of water are called trioses; as hexotriose, etc. 
Like aldehydes, the aldoses are nonverted by oxidation into 
moiKiliaHiu acids coutainiug the suiae number of carbon atoms, 
the puntutieB yielding the monobasic ptnlomc acide, and the 
liDxowis yioIdiuK tb* hcxonic adds, etc. The oxidation can 
be curried further; for thu general formula of an aldose is 

CH,On{CnOH)„-C<" (309), and the group C1I,0U can be 

oxidized to carboxyl, yielding a dibaEic acid containing the eamo 
number of ■carbon atoms as tJio alioeo frnm whicb it is derived. 
On oxidation, the ketosos yield acids containing a Bmaller namber 
of carbon atoms. 

On radnctinn, the aldoses and ketoKB take up two hydrogea 
atoms, with fornmtion of the curreepondtng alcohols; thus, hcxose 
yields a kexahydrie akohol, and pentose a pentahydric alcohol {309 
and Sll). 

208. Fonr rcactionx are known vhich arc charaoteriutic of all 
monoges; two of these they poseeiia in common with the aldchvdes 
(116). 

1. They reduce uii amwonincal silver solution on warming, 
forming a metallic mirror. 

2. Whon warmed with nlknlitt, they give ^ yellow, and then a 
brown, eoloiiratinn, and ultimately resinify. 

3. When an alkaline copper solution (Feuuxq or OsT, 192) 
is heated with a nnlution of a mnnose, reduction takiM place, vith 
formation of yellow-red Muboxide of copper. 

4. When a monoeo id heated with oxcew of phonylhydTaiino, 
C,H, •NU-NH, . indilntoncetin-onid Rolntion, a yellow oomponiid, 
ciystalliziug iu Uno needles, is fonned; substances of this typ« 



a^ft 



ORGANIC CHEMISTRY, 



aro insoluble in wuter^ and are called osatotus. Their formntioa 
may be explaiuuil in the following way. 

It iraa laL-iitiuued in 206 that the sugars are characterised'^ 
by Uieir containing tlic Rroup — CflOLI— CO — . The action of 
pheDyIhT<)raziDe on n carWnyl-group hae been already explaiof 
(113); water is eHmiualeil, aud a liyilrazoue i^ fonaed: 



ilo 



+ i-[, ]y • KiK'.n, = c : N • Nnc,H, + n,o. 



A seooDd molecule of plienylhydrazine then reacts with tlio group 
■ — CHOH — , Troin which iwo hydrogen aloma are eliminated, the 
molecule of phenylbydruziue being ^plit up into auuuoniu and 
aniline: 



cn,-Nir-NH, 

Phuiiylliyilraxiiio 



-I- H H 



Antliu* 



The removal of two hydrogen atoms from the pronp — CHOTI — 
converts it into a rarbonyi -group, — VO — , with which a third 
molecule of phenylhydrtuiuc rtiacts, forming a hydrazone, so that 

cHon c=rX-Nnc,H, 

tho group t is converted into | ; this group 

CO C = N-NUC,n, 



is eharacierigtie of (he omtones. 

The osazonos dissolve in wator with difficulty, and tliis property 
makea them of great service in the separation of the mouo»es, since 
thttsoeubBtancea are very soluble in water, and crystallise with great 
difficulty, o8pei:ially in prennnrc- of fuUt»; eo thnt their purification 
by thia method Is often impracticjvble. liy moans of tho epanngly 
soluble osaxoneg, howovor, thoycJin bo separated; thceo are readily 
obtained in the pore stale by cryetallizatiou from a dilate solution 
of pyridine (386). Moreover, the identity of the monoac can be 
OBtabliahed by a determtnation of the melting-poiat of the oaasom 
thuB obtained. 



Comtitntion of th« Modom*. 



209. It will bo ehowQ tntor that tho congtitation of &I1 tbcl 
monoKos folIoKs from th»t of the ftldohnxoWB, whoeastrocturo may' 
be dedncetl in the following way. 

1. The aldohesoBPs have the molecular formnia CJI„0,. 

2. Tho aldohexoBes an) aldohydco, and, tli«reforo, contain ft 
carbonyl-group iu tho moleculo. This follows from the fact that 
they »how tho roiictiong peculiar to aidohydos; that they aro con- 
TeiUA by oxidatiou into acidH coDtaining tho same number of 
C*aloii]g, and by reduction into an alcohol; and that tlioy have the 
power of fonniug a<idition-prodHctfl with liydrocjuuic acid. 

3. All kcown hexoses contain a normal chaJD of six carbon 
atoms, since they can be reduced to a hexahydrio alcohol, which, 
on farther reduction at a high temppratiirL> with hydriodic acid, 
yields a-aecoudary hoiyl iodide, CH, ■ CII, • CHI ■ CH, • CII, • CH,. 

Tho cooslltDlion of this todido in inferred (rom tbc tact that it oaa 
be coiiTOctcd into no alcolio), which on oxidatiou yields 
CH,-CH,.CO.CII,-Cn,-CH.-. 

for oa further oxidntiua this la converted into n-butyric and nceUe 
adds. 

4. The hexoses hare five Lydroxyl-groape, siuce, wheu heated 
with acetic anhydride and a small quantity of sodium acetate or 
line chloride, they yield penta-acetyl-dcriTatiTee. 

These factii indicate thv existence, in an aldohezose, of 



a normal carbon chain, C— C — C — C — C — C; 



C— C— C— C— C— c < 



C— c— C— C— C— c^ 

0H<!>nbH<!>n&ii 



O' 

H 



an aldehyde-gronp, 
fire hydro xyl-groupB, 



Tliere are six other hydrogen atoms in the formula C,n„0,, and 
these will fit in with the la«t scheme, if the C-atoma of the chain 
are singly linked to each other; the formula of an aldohexose will 
then bo 

CH.— CH— CH— CH— CH— C<§ 

^H 6U 6h 6h (!)H 




J58 



ORGANIC CHEMISTRY. 



In these formuls & somewhat arbitrary assamption has boeu 
m»A9 as to the distribution of the hjdroxyl-groups ftnd liydrogQn 
atoniB relntive to the carbon atoma; it ia^ however, in aocordanoe 
vith the rule (13&J that a carbon atom caiiuot usiully be linked 
to more than one hydroxyl-group. A more oonvincinjf proof of 
the fact that the muuosiA <Io not contain two hydroxy! -groups tn 
unioa with the mmo carbon atonic may bo deduced from tbo fo]> 
loving consideration*. 

When a hexoBc, 0,H„0, , is redace<J too hexahydric alcohol, 
C,II,,0,, only two hydroj;en utonm are added on, and this addition 
most take place at the doubly-liukud oxygen atom, since the carbon 
ehuin remains iinbrokou. If the hexow oontajcs two hydroxyl- 
jrrotipH in union with one carbon atom, the Mune miut, therefore, 
hold good for tho hexahydric alcohol dorived from it C^>mpounda 
eontnintng a C-atom in nnion with two QH-groups readily uplit off 
wntor, with formation of aldehydes or ketones; they also possois 
most of the prnpcrtiee characteristic of these aabstancea (804)- 
Tho hexahydric alcohols, howovi-r, luive an cxclainTely alcoholic 
^K chaructor, and do not exhibit any of tho reactions pecnliar to the 
^^ aldehyde* and ketones. It follows that tho hesahydric alcohols, 
I and hence tho hoxoMS, cannot contain two bydroxyl-gronpa ItDked 

I to a single carbon atom. 

I The possibility of three hydroryl-groops being in union with 

i one carbon atom is also excluded, siuco, when the prodnction of 

E a compound with such u ^ouping might be expected, water i> 

^^ always split off, with forautioD of an acid (88): 



0H| 
— COiH 

TOH 



The monosM have none of tho propertiai whioh distinguish acids: 
when in aciacons solution, they do not conduct the electric current; 
whereas the dissociation constant for an acid containing so many 
OU-groupB should be considerably higher than for a aatarated 
£stty acid, such as acetic acid (183). 

Wilh calcium and stmntiuin hjdrozides, and other bases, the car- 
bobydratea form oompounda callad aooaAaratst, whiob are, therefore, 
to be looked upon as aloobc^ates, Tb«y are decompoaed by carbouia 
add. 



TntOOS OF fORMATlOS OF THE MONOSES. 



*5< 



From what has been raid, it will bo aeon thut tho constitution ' 
cf tho sldolujxoeeti csuuot bti* other thaii t)Lat given ahoro, and, 
einc« the same method of jirixif \& applitrablc to each member, thoy 
must all hare the xamo constitutional fnrmulii, and are therefore 
etcrooisomors. This ia duo to the presence in thi> raolecule of 
ujmmctric carbon atoms; un .ildoliexOHo has four such atome, 
indicated by asterisks in the formula 

Cli^OH-CUOUUHOII-UUOH.C^HOU-C^. 



lletb«U of Forauition. of tbc f4l)B0MB. 



210. 1 . From the polyofws, by hydioljais; thnt is, deoomposi- 
tion with addition of WHt4<r (206). 

2. From the correnpondiug alcohols, by the action of oxidiz- 
iog-a^nts, such as nitric acid, la this way arabitol, C,lt,.0^, 
yields arabinofie. (^sll,^0g; sylitol yields xyloecj mauuitol yields 
man nose, et«. 

Wliea glyoerol is carefullr oxidized mth nilrio acid, or trjth bro- 
mluenndcniutifl lodx. a syrupy liquid i.>t oblained, wliicb slioirs ilia 
(our rcactiorui glrva on p. 355 for I be monoMs ; it is called glyctme. 
It* osaxoue, fflycerotojom, 

CII.OH 

6=NNH-C,U. 
H 

crrslalhzctt in yellov loeiTM, nieUiog nt 131°. Olycorose |ft dihydmxjf 
aettone, CH,OH-«iCl!,On, (w Is prove>l by ih« eyanhydrln syn- 
(he^ (IM, 8], by lucaus of which tritiydrozyisobutyho acU, 




ou,ou-C-cn^H, 

COOH 

Is obtained. The siructure of this acid follows Trom its reductioo to 
Isobotyric aci<I. In aooonlAnoe with the nometiclsturo already indW 
c*ted, f;lyoerose is a tritite. 

WhoQ lead gljccrate is oxldixod with bromine, tbe product, besJdet 
•iihydroxyaootono, ooDtalns glyocraidubydo; tho presouce of tbi« sub- 



i 



s6o 



ORGANIC CHEMISTRY. 




U&ae* Is i)rov«d bjr ii« fomiDg ft ciTStftllizod ooDdcDsatioa-prodtict 
with pblorogiucioul (SU) : 

o.u,o, + M'.H.O, = C,J1„0,+ DA 
Oljnwr- ?iiioro- 

KliMjlt* Blucuni 

Dib]rdn>xyac«toi)Q does noL yiold a similar oxidatioa-prodiict. 

Glyoeraldabyde can bu ubtmiied ia tbe pure stue by tivaiing ih» 
«cutal of ncrol«Tii willi n dilate solation of potossiam pcrmaRsnnatn 
(117, ij, and removiug tlie two — OCIIt-groaps of llio occ'tal bjr 
means of diliito Bulphnrio add (lit. £). *"- 

U'h«n sorlK»«-biu:t«rla src culiivnted in a soluUoii of (^yoeral. th« 
Snal protluot oblainctl by tlio action of iho Atnnsphcric oxy)[eii is 
diliydraxyacctoue. Tbew baoteria oaii oxidiw otlier moDoocs lo 
kdoees. 

3. ProRi bromo-componnilB of aldehydes, by exchange of 
bromine for hydroxyl, whiub can be effected bjr cold boryta-witter. 

In this miuiner thft niniplest member of the BO^urs, ffti/eoiU»Ubh]/d» 

WJ 11 

CH|OU-C" tn «bt«iti«l from inotiobromonldoliydv. aif,Br-OQ; It 



Bhovrs All the r«actiona of tlio monom. 

TttD addition of bromine to acrolein i.W) yields CH.BF-CFTBr-C 



B 
O' 



vlticb I» converl^d by tlia action of baryta- water ioUi giyoendddtyde. 

4. From forraoldehydo, by the action of lime-water (aldol 
comieiiHation). The crude coudeusation-produet, called foimoso, 
ia a Hvreet, syrupy HubaUnce; it conaists of amixtureof compotinds 
of lilt' formuU C,1:I„0,. In this reaction, six molecules of form, 
aldeliydo undergo lite itldol condensstimi (115): 



H,CO + iICO + UCO + HCO + IICO + HCO = 



By the aid of sunligbt and moUturo, plaii(s sro abls to connrt 
tbe carbon dioxide of the Atmosphere into siarcb. a polyoM of itio 







Bazykr liMtuggeM»d that the CO. 1« tint iwIucmI U> rormaldelirde, 
0H/>, ffhiflh Modenses to a mouoae, the latter b«ii)g tboii converted 
into tbe polyose. march. 

BenTHRUfT h.is obtiiiaed sitbal&noos of llio n&ttm of carboliydrat«a 
by tb« ftctioii or a silviit elviatric dJGclmrge oti a mixLtire of oatboD 
dioxid«, ourlMD monoxide, aud hydroKeu. 

A hoxom; can iilso ha otituinttd from glyceraHehjdo, two 
^(noleciilos of wliich yield, by tbo aldol coiidensutiou, one molecule 
the hoxosc. This boxoso vs called aerote, on account of its rela- 
lioii to Hnrolein, from which glyccmldohydo can bo obtiiined by 
^inrlliqil .'i. Acmse is a. constituent of forinose, and, like all 
Bbotupounds jiri!parod by purely chemical syntheBie, is optically 

^^^D. A very Lmportant geaenl method for l.he cooversioiL of an 
aldoso int« another contuiniug one more carbon atom in tlie mole- 
cule is the formation of nn additiuu-product with bydrucyanto auid. 
An aldobexose yields ik cyanbydriii which h convvrted uu hydro- 
lynB into a monobasic acid containing soren C-utums. 

H CH.OH -CnOU • CHOH -f HOH ■ OUOH ■ CHOH ■ COOU. 

■ 12 3 4 5 6 7 

HSCho ^'-hydroxy] -group easily reacLii with the carboxyl-groap, 
Hjbrmiug a lactone, 

H CH,OH • CHOH • CHOH • CH • CHOH • CHOU • CO. 

k - I 6 - 

/N itquwus aoiuiion, th«i« iaelttnet can At roduetd hg Mdiutn amaU 

^«MB io tke oorrefponding aldthyi»t, ilie aldmes. 

^H The greiit importsnci! of this itj'nthesis oousiatii in the theoret- 

^|pd pOBtibility of obtaining from th<< lower mcmbHrx, stvp by utep. 

^nldoAcfl irith uuy deiiired numWr of ('■atumE tu the mulucule, by 
repeated application of the cyuahydriu gyutbcAiu, and rvductioD 
of the lactone thug oblnincd- In this manner, it has been posgible 
to prepare ««wo««, with nine C-ntomR, by conveniion of an aldo- 
hexoao iuto a heptonie acid, whoste lactone can then be reduced to 
s hvptost^ This compound can be i;oiivcrlL-d into aa octote, and 
latter into a nonooo, by thu eamu proccas. 





««2 



ORGANIC CHEMISTRY. 



I. UOHOaEB. 

Fentoieft. 

211, A reference has uJready been made to the bioscs and 
trioees (207). Tetroscs can bo obtained by the oxidation of pent-y 
onic acid, in the form of its raJcium Halt, by moaiis of hydro^ 
peroxide, a small quantity of firric acetate being used as & 
, catalytic agent: 

CHjOHCHOHCHOHCHOHCOOH + O - 

raDluDlcacId 

- cH,oirciioiicnon-cfJ + oo, + h^o. 

T«tt(ue U 

Also pentoses coii be obtained fmrti hexoses by this method. 

A nxunbor of different pentoses have bet'ii i<Ien1ificd; of th« 
arabinme and zylos^, both of which are present in many plants 
polyoses, called peniosnns, may be considered. 

Arabinose can be prepared bj' boiling giim-nrabic or cherry- 
gum with dilute acidjs. Xifhsc, or ivnodsuyar, can be got in the 
same way from bran, wood, straw, and other substances, especially 
the ^lella of apricot-stones. Arabinose and xylose can be prcpar 
from any plant-celb which have been converted into wood, andl 
wluL'h [>ossese the roaollung of liguin (230). The racetnic modi- 
ficatiou of arabinose is present in the urine of patient* suffering 
I Irom thf disease knuvvn aa pentosuria. 

AnilMnose forma well-defined crystals, melts at 160", and baa 
- a sn'cct tatste. Ite osazoric melt^ ut 157°. Xylose also cr>'staltizce 
' well, and yields an osajEonc which melts at 1()Q°. 

Arabinose and xylose are aldoses, and haw the same formula, 

CR,OHCHOH-CHOH-CHOH-C^. 

This constitution is proved by their conversion, on gentle oxida- 
tion wiifibmminp-vrater, into nmfc»iif>a/-iW and njl^c aciti rvspc-ci- 
ivdy, br^th of which have the fommla riljOlI-{CHOH),-OXiH, 
and are therefore stereoiaomprs. <)n stmnger oxidation, both arabin- 
ose and xylose yield friVM/driwyy^wJ'aru- am/, CX)0H(CHOH J, -CXX)!!, 
the constitution of which follows from its n'<Ii»rti'm to glutaric 
acid. The acid obtained from arabinnst! is optically active, and 
tliat frtini xylose is inactive, so that they, I^hi, arr sterr<it»on)eis. 
On n-ducUou, tbeae two pentusui yield rrt*i>cctivcly arabUoi and 



PENTOSES. 



»63 



xjflilol, which are stereoisomeric pcntahytlric olcoliois. Arabinosc 
and xyloee can be converte<i into hextwics by the c>'anhydrin 
Kynthesis, a proof that neither coiitaian a C-atrmi in union with 
more tlmu ooe OH-group (209): 

CH,OH(CHOH),-cJJ -» CH,0H-(CH0H),'C<9» -V 



CH,OII.[CII0]a.CilOH-CO0H. 



fhis hexonic acid j-ifUls a laftono which, on induction, pivcs the 
hcocoBP, Arabiuiwe and xylose contain three asymmetric C-atoma, 
and are optically active. Tlieir aqiipous solutions, in common 
with those of several other nptirally active substances, ejchihit a 
phenomenon called initlti-rolait'oti, fresh solutions rotating the 
plane of polarization much more than those which have stood for 
gome time. For xylose, five minute? ftftor it has (wf-n dissolved, 
the value of [a] is 75°-S0°; this pndually iliminislies to 19*, 
after which it remains constant. 

This phetomonon is probably due to tlio conversion i>( the sub- 
sliLiicQ iiiio aii<>i)ii;r imxllflciiLlon, nnnlogous to lliat of lactooos into 
acltb. Tlim, a tTvuh aoluiiou at xylose would coalaio 

OU.OU-Caon-CHOH-OH-CoH 
O 

While lfttoreU,OU.(Onon)fCnon-c{5 is formed, This viow Issup- 

poned br the fact that tlie rotaiory power of a lactone ib dimiuished 
by op«iiiii£ its riDK; an example of (his is furnibbeil by j^nluctouio 
acid, only that in it the chaugc of rotatory power takea pUca more 
quickly t)ian amon^ sn^pirft. 

The probability of the correctness of this ieterpretatioD is stien(tta- 
«iiod by the fact that the ohango of Totatory power has lliA obarftct«r 
of a uuimolecular reaction. 

The pentoses have one property in common, by which they may 
be recognixed and distingiii.>ihed from hexoses. When txiiled with 
dilute sul[jhuric acid, or iiydruchhirio acid of sp. gr. 1 ■ ()6, the pent- 
oses and their pulyoaes funn a vtdatile compound, fiiTJuraldehyde, 
C^HjO, C391), which, on ireaUiient with aniline and hydwcliloric 
acid, yields an intense red dye. 



aH ORGANIC CHEMISTRY. 

TIm pMMBM or tho polfoso of xylow mny be det«et«d tn such a| 
substuntM; OB sftaw, by tlistillntioti with byiirochlorio acid of »p, gr, 1 08 
Vitli BUJli[it.> atiil b^vdruciiluric »oid. tbe ilUtillato givt-R su iDteDse red 
colourfttinr, and with phenyl hydrazine yield* a phenylhydranone fvrji 
sparingly soluble id water. Botli tb«se reactions indicate tbe [iresaneti^ 
of furfunildehj'de. 



Eexosea. 

212. The hexosn are colourlens compoucds of sn'cet Xnt^s, 
which orj'staltizc with difficully, and cannot be diAtillcH without 
df'cnitiijfxsitinn. Th(^y dissulve n-adilv in water, with itifficiilty in 
aiwuhito alruhi>I, and are insohibk- in I'ther. Sint-e all (he ald<>- 
licxfisrs an- slrn-oiaonicrs (SOS), tlifir oxidation-products, the 
nionnljiistc (ind dibask- aci\\s, an* alao stereoiiKiiiuTS. 

1. (/Ywcoac, f>r Krape-su^ar. is prfsi'iii in many plants, notably in 
the juice of grapes, and in other swoct fruits; it ia found in the 
urine of diabetir patipnlii, and in small cjuantitics in normal urine. 
It can lie ohtained fmm many polycwM^; cane-siignr is converted 
by liydmlytiis — invir»ion, C217)~inIo n mixture of glucose anj 
fnirtnwr, oaik-d iniTii-HugiiT. ]iy the same trralment, stArch 
yields gluoftse, which ia tochnically prepared from it by boiling 
with dilut* acids. 

(ilucosc crystallizes from water, op alcohol, with some difR- 
culty; the crystals obtained fmm methyl alcohol contain no water 
of crystallization, and ntelt at 1+6°. It has been already men- 
tioned (47) (hat ^iKicose ran be readily fprmented, producing chiefly 
alcohol and carbon dioxide. iK is dcxtro-rotator>', and exhibits 
multi-rotation; a ia-vo-rotator^* and an optically inactive modifi- 
cation have been artificially prepared. The dextro-rotatory, Ubvo- 
rotstory, and optically inacti%'e isomers are respectively diatin- 
guished by the prefixes d (dexter), I {litvus), and £ iinaclive); thus, 
f^-glucoee, ^glucose, i-glucoee. 

By ooiivoulion, all oth«r monoMs tlorivod from a d-, 1-, or {• 
bezoM are also dtstinguiatied by the letlers d, L, or i, «vea wboo 
tbejT poaaeas a rotAtory power opposite in sifcn tn that iadtoated 
these letters!. In thin way, ordinary fruotose, which can be obtain 
froDl (^glucono, uDil is lutvo- roUlory, ia oallvd rf-fruotose on Hccoac 
oftls genoltc rols.tfoii to ti-giaao&e. The samo method of cUssie 
lion ia adopted for the beialiydric akohola, the hcxoolo acids, and to 
(emrtl for all derlTatives of tbe hexoses. 



HEXOSES. 



if-Gluwtfo is an aldose, as is proved by its oxjflation to a hex- 

Onicacid. li^fufome aCTVf,CH,0H-(CH0H3,-COOH; further oxidi^. 

Uon proihieps ihc dibasic rf-saccharii; aeid, C{K)H ■ (CHOHl^-COOH. ' 

Snccbaric ncid forms u charai'li^ristio nd<l pota&sium aall at Hliglit 

aolubiliiy. which servta aa a lest for tt-eiueoav. Tlie subslniicc »us- 

p«ct«il to conlniu glucoM is oxidiiii'^I with nunc Jicid ; s««ch.nric acid 

is pHHlitci-tt frum cliis licirac, if pr<;^iit, and can bo precipitated in 

tlie fonii of till.' uulil piKiisKiuiii Mlt by ailditioa of a concentrated 

solution of poi'iLsiiium acetate. 

On reduction, if-glucosc j-ields a hexahydrie alco!iol, d-atirfnlot; 
It also gi^'es an nsazojie, {\tjltifosaiom-, which is stduble with diDi- 
euttv in water, and rn.'stallizcs in yellow ncedlet* which melt at 

d-Cilucose ia mnployed as a subfttitiitc for cane-sugar, and 
applied to nmity ntlit>r puriwses, on account of its sweet tasto, 
which is however lewt prommnced thsii Lhat of caiie-migar. With 
a i^niall quantity of water, it yirida a coloiirless syrup, used in the 
preparation of liciucurx and of con ftretiom-ry. 

2. d-t'ru^^tosc is prcseul aluii^ with </-gluc'>sc in njost s\*'eet 
its. It is a constitiient of invert-sugar (217), and of honey, which 
ia chiefly a natuml invcrt-innger, tnuUn is n polyosc contained in 
dahiia-tubers , and when hydrolyneif, yields only rf-fmetose, just, as 
starch yields if-ghicose. rf-Fnicto.'«e cn-stallizes witli difficulty, 
being readily solublr in water, ftlthoiigh less so than grape-sugar. 
^It is Iffivo-rotatwry, and can Iw fermented, 

d-Fructose is a type of the Icctoses. few of which are known. 

[Ita formula, CH,OH.(CHOH), CO-CH,OH, is deduciWe frotn the 

tfoUowing con«derations. First, when oxidij^cd with mercuric oxidaj 

iln presence of baryta-water, it is converted into glycolUc aac 

CHjOH-COOH, and trihydmxyglutaric acid, " ? 

coon-(cnoH),-cooii. 

^Since oxidation takes place in the cariwnyl-group, the production 
Htif these acids necessitates the adoption of this constitutional 
Bfonnula. Second, applicaiion of the cyanhydrin synthesis to a 
H eompound of this constitution would yield a heptonic acid with, 
the formula 

»CH,OH - (CH(OH),- C(OH) -CH.OH. 
ixiOH 
That the heptonic acid obtained from d-fnicttMe haa this consti- 



Bfruit 



sfiti 



ORGANIC CHEMISTRY. 



tulion, ia proved by heating it at ft high temperature n-ith 
hydriodic acid, whereby all the hvdroxyl-groups are replaced by 
hydrogen, and a heptylic acid is fonned. This is found to be 
identical with the Bv-mh^tieally-prepared meth}firTi'bul\fiacetic acid. 
(S3&, 2), whoso coixstitutiunal formula is 

CH,-(CH,),.CH-CR, 

Tlie asazone of ri-fnicinw i^ identieal with that of d-gluoose. A 
coniparisun of the fnniiula of f/-ghicoac, 

CHjOH ■ (CUOU), ■ CHOH ■ Cy , 

with thatofd-fnittosL>,CH,OH.(CHOH)^-CO-CH,OH, shows that 
the two wsaaunes caii only be i<lrnticiij if the fr-0«.l(Hi» t>f lh^l'/-K:lu-^ 
cose, and the tcmuiial C-atom of the rf-fnictose, unite, after for- 
mntinn of the hydrarone, with iho second phcnylbvdrazinc-refudue ; 
that is, when ui hulh eases thin n>aetii)ii taki'S place at a C-alom 
dtn>ctly linked to a earliiinyl-gnnip. For lliis reason, il is aasumed 
that the forntation of an DsaEiintr always iraulta in the union of 
two phenylhydnudne-residufa with iieiglilwurinK C-atoma. The 
glufx)sazoiu;, or fnictusazonf, has the cuustituliua 

(CHOH), 
C-NNH.C,H, 

H 

It is a somewbat remarkable fact that methylphenylhydraxtne^ 
C^Hg- N(CH,) ■ NHj, yields osazones only with ketoses. and not with 
aldnses. The Inlter form colourlej« hydraBoiies willi this com- 
pound, and these can easily be separated from the iatcnstdy' 
yellow osazoncs. Mclhylphenylhydnizine therefore affords • valu- 
able means of deteeliiig ketostw. 

When the osazones are earefully warnieil willi liydrooblorio aojil, 

two molecules of phedvllij-clmziiie are split olT, wtih ronnation of oom- 

poaadfl, oKOfief, eontniniDg iwo CKcbooyl-groups. Id tbls way, gUu>- 

osaEono yields gluwutm^ 



CH,OH-lCHOH),.CO-0, 



O* 



a67 



^m Otlu 

■ CH, 



The OBonDS cnn ba rocluccd by tnwLmVDt with zino-doat and ncvtic 
acid, and eipurieiic« lias sbown that addition of hydrogen »laayi 
lAkes |ilAce ai tbo tcrmliikl ('-«tou). Oliicoeone yields fruvtijot- 
CH,OH.{0HOH),-C0-CH,On. This njuciion afforda n mennsof eon- 
Tortiog aldoeea into ketones: 

Aldotio — Ouuone -* 0«ooo -• Kelotw. 

loTcnol}', nn nldose caa be oUiuned from a ketooe. On reduction, 
the Inner yivldsa bexali^rdric alcohol, which l8 C0DVurl«d by oxidiitioii 
into a oionobasia hox»n>c ucid. This subetanoo aplita oS water, yicld- 
Int; llie corresponding lactonti, whiob on rviluotlon git'oe the aldose : 

Kclnsp -* IlQSnbydric Atcniiol -* Hoxonle Acid -• [jictoiic-* Aldose, 
3. d-Mantwa^ in an aldose, and is present as & puly<«sr in tlie 
Tcgct able-ivory mit; it is alao oblainetl by the cart-ful oxidation of 
the hcxahydric alcohol mannitol, touiul in uevonil planta. d-Mannosc, 
a hard, amorphoiiB, hygro«enpic«ulwtance, can ho n-fldily fprm^nteii, 
and is vt'ty Kolublo in water. It fornis a rtmroctt'rLstic hydrnxone 
which melts at lOS'-SflO", arui, luililcc: iIih hydraaones of the 
other monosos, (li«sc»lvna witli difficuhy in water. On oxidation, 
rf-monnoBc i» first convcrtrfl into tlic monnbaxit; tl-jiuumonic acid. 
Cn,0H-(CIIOH),-C00Ii, a»d then into the dibasic d-manw 
^xhark acid, C0OH-(CHOH).000H. It yields (/-glucose by a 
;ho<I gnncrally applicabk* Xm \\w conversion of aldoses into their 
stereoitfomers. For this purpose, ii is firet convorWKl intorf-mann- 
onic aeiil; this is heated, preferably by boiling its soUiiinn In 
quinoliniN winch eoiiverta it parti}' ijito the atercoisonieric rf-ghio 
onic anid, whose lactone can be reduced to (/-sIucom*. Inverwly, 
4J-gluoonio acid is partly change^ into (/-niannonic acid, by Ixiiting 
its quinoline solution, so that j-gluetiw; can be converted iiilo 
cf-mannoso. 

MauuoDic acid ia one of tbo intBrincdiato prodnols ia Bun. 
FiscHKitN synthesis of (/-glucose. lie conrerted gljroeraldehjde Into 
vxxwe fSlO, 4), ami llii« inio i-Bi.innilol, by rciluction wilU iwdiuni 
atiiiilgittu. On oxiditltoii. ^-manoitol yit-lds Dm i-maniins^, and 
tboa t-mauQoniv ncid, Aliidi cnii be *f>IiC U{>, by mranaof its etrycb- 
nine s:ill, into its opiiadly aclive modtAcnlioDS. Wliva tbe O-voBa- 
nonic acid-iliiu •^l>t{iiiiAl ix bonled willi pyridlno, il ia converted into 
d-glucouic add, ilie kcii>Q« of wblcli, ou reduotioii with sodium amal- 
gam, yieldarf-glucodo, 

The stcreoisoinerism of ti-tnannosc and (/-gltiorote, as well as o( 
moanonic ucid and (J-glucuuic acid, is uccaaioned onlv by difTcrent 



968 



ORGANIC CHEMISTRY, 



grouping round the a-C-atutn, sinoe the nsaxono of rf-m&nnose w 
identical with that oi (/-^ucose. Aa this has the cotistitutioa 

CH,OHCnOUCnOU CHOH-C— C-NMl c,n,, 

N NHCJI, 

tbeae (wuonca can only be Ulentical when tb« residue 

CHjOH ■ (CHOH), ■ CHOH— 

in (f-Dianoost! and d-glucose is also idi'ntJcal; their Rl«reotsoimeriani 
caa then outy result rroiii a diflTerencc lu the airaogpjiipnt of the 
groups linked to the a-C-atom, 

So for as the tnuisfommtiona of the nioDoba^ir liexonic acids 
when boilod n-ith quinolinc or p\*ridme. have bw^n studied, it luia 
alwa\'8 t>o€n found ttist an alt'-ration takc-^ place, as in the above 
iiunancp, at only one C-atom, the one adjoining the aldehyde- 
group, the a-C-atom. 

Very remarlcablo ia the conversion into eacli i^tior, dinov-ered bjr 
LoBsr DR Bkutm, of glucose, frndtose, nnd nianiio««, under the iuOa- 
i-iicv of wry (lilutu nikulb. Tlieir rutntorj power is coDftMlerably 
reduced thereby; Mcb of tlioM hoxoaes fornu both lUe otfacra, and tba 
oDe oriinRaUy prcseol is not completvlv ooQTorced. An (xjuilibriun 
is thus eotablishod vrbi«li mvf be reprosenied t>y iliesobonio 

Glucose ~* FruotoM *~* ^twoK. 

Thai frudoM b ncLunlltr an tiitAniioc]liit(> prodiiot n( this transronna* 
tion, is stiovrn by Ihu buluiTimir of llio dtxtro-rotatoT)' eolation of 
mannoee, vrhiuli, owiii); tu tlid rormntiuii uf Friiorose, first deretopa 
iBvo-rolAtioii, this grsd sally ticoroiuiiig na tho dcxtro-rotalorr gloooso 
Ir produced. 

4 mid IS. l-fflniooM and \-maHn'nit aro inijiortaiit on acoount of 
tbeir molliixl of rurm«li»a. Tlwy nutull tiaiiiltaiieously from /-am- 
biooM by npitlication of tlio cyAnhydriii synthesis, and mdootion of 
tba lacioae of the neld thos forined. It was nittntioiied (IH) wby the 
application of tlii* syotlivsia to aldchyd«* Mlmnys Icnda to ibe prodoo- 
tlon of two stereoisotnent ; an MymoMtrio C-atom results, and ooa 
optionllj actire iaomor is as likely to be formed &a tho other. In tba 
ease of ^rabinoie, there nre asymmetric C^aloma already pre^eoi in 
tb« molecuitt, and an aidiUoiml one 'm prodtwed by tbu syotticaia; tUo 
ilomeiK display disaimilar rotAlor; power, but this is no longer «{aal 
and opposite in si^a, stnco the original rolatioo is inemsed in oae 



MONOSES. 

Isnmer by the now iLsymnifltrio C-ntiiin to lltn lutmn «sfptit ns It is 
dimioisbed in ttie uOiur. Th<; rolntioii of Uio isomers is equal and of 
opiMclta sifpi only when Iho originnl iiiolw»]e wns optically inaotiva. 

6. d-Gaiaciose can be obtained by the hy»bt)Iy3is of lactose, or 
by the oxidation of the hexahydric alcoliol ditIfi(ol, utiich ot-cur* hi 
certain plants, tf-^^alactoee is cr>'stalliDc, mcUiiiK at 1GS°; it is 
strongly dextro-rotatory, is capable of imdcTBoing fermentation, 
and exhibits multi-rotalion. Gala(-tn,w is proved to he an alilose 
by it« conversion, on oxidation, irit^ the nionohasic d'^jaiactonic 
ocw/,C,n„0,. Further oxidation yields the sparingly soluble 
dibasic mttcu: (wnVi,(XM)n.C('HOH),-a>(.)n, which h opiirally In- 
active, and cannot be split up into opticjiUy active component; its 
fonaation serves aa a test for (/-galactose. In practice ibis is carried 
out by oxidizing the hexose under exam ina lion with nitric acid. 

Their couvorsion into lofmtlinie acid (236), on trL>ulint?nt with 
hydrocliloric avid, constitutes a general reaction for the bexos(«. 
Brown, amnrphous iiijiss«*, known as "liunius BulwtanM's." arc pro- 
duced at tiiesuine; time. LiL-viilinic acid can be idciitific-d by ineaits 
of its silver salt, which diaaolvea with difficulty, and yields crystals 
of oharact eristic appearance. 

HeptoBSB, Ootoses, and Noaona. 

21S. Tlicse aubatancOs arc notriatund producls, but can be built up 
from the hexowd by tb« cyanliydriu synlbesin; miinnofle, for example, 
jteldi mannolieiatut, matuuMtc/iMe. mid mannonomuie. 



i^/ 



Stereochemiitry of the Moaoses. 

114. It wasiitator! (SOO) Llial all the aldohcxosea and aldopontoaM 
haT« th« H-ime structure, aa that their isomerisni iDu<it be starMian- 
inerixm. AUIidukIi H would be licyond the scopo uf this bunk to 
dvdDOo tho CMtf\)|:tirullnii parrciipon'tm}^ to tlie; pGnlwcm and licxoiiiis 
nteDtioncd in tl, it is dc»iral>l^ to indiciitu how lhi» id deturnainud fur 
Mmpoundi of ttiis kind; Hint i«, for tboM wnialnlng several aayni- 
tDctric car1»n atoms in Ibc molcculo. 

It was mciilioned (191) tlint tliu presence of two dissfniilar aaym- 
tDOtrii; C-Hloniit in a muleculr cnuacs the osiatenoe of a greater 
namber nf ftU'r«nii(omerA Ihan tbat of two aimilar asymmetrio C-atoma. 
Il can be readily tasw fmin a projtictiori- formula thai ttia aaiti« liolds 
good for a greater nmuber of nityrnmrtHc (.^.alnnis in tlic mu1<wiile. 
The pro jwtioii- formulae for fwo aldo;i«iiti>s««. 



S70 



ORGANIC CHEMISTRY. 




and 



H- 

H- 



««OD«t bo made to eoicuiido by roUtton in lb* pliiii* of tbe p»per 
(191); th« nldopcDtows. ihvntorv, arc aot identical. Tha correspond- 
ing tTlhjdrozygluiano acids 



COOH 



HO- 
HO- 
HO- 



-H 
-H 



and 



H- 
H- 
H- 




(^ 



COOH 
OH 

-\ OH 

OH 



CX)OH 



COOH 



KTO, hofr«Ter, idcnticat, sinoo (heir proJKtion-fomulie e«a b« mad« 
to ooiDCido. Ill th(!fto oompoQiuK lh« asymuetric OaUnat 1 and 8 
kn simitar, wbiU Id tb« p«nto«e« th«y ara diMlmitar. 

Aasamiitg that tbe detcnmuaiioo of the coofl^uratioa of tri- 
ltydroz]ri;:lutano acid is pouib)«, and that in a given instance it leads 
to the projevlioii-rorinula given abore, it foItoKn tltat tbe pentostf 
froin wbtcb it ix obtaiacd by ozid&lion miut hare one of the abovr 
configurations, anil that all others are deluded. Il tbiu ooty renutimi 
to distinguish between theM two configurations. 

lo order to detennioo the stcreocbcmica] stnu-ture of a pentou, it is. 
th«refore, first necessar/ to determine tbat of th« correajMnding Irihy- 
droty^liiljtrlc iicid. Tbe optical bebaWour of tbeae acids aifords a 
rwidy mcfUJH of ffTncting this. XyUutn, which is o[>licallT actire, \i 
conrcrtcd by oxidittiun into au optically inaclivo tnhydroiyglutanc 
aeid which melta at 13S*. Since au optically inactive anhstnaoeis here 
obtained from an optically active one. not from .i raoemio oumpouml. 
lUa BKUtt be occasioned by intramolecular compensation, which most 
And ezproa^oD lo tbe conlijruration allotted to Ibis piulicular iribr- 
droxyglotaric acid. Proji<«tfi>n-fonnuliD of eon^tonnds wliteh ar« 
optically inactive on account of intramolcoular oouiproaaiion must 
fulfil this oondition: each and its DiirrorimagD ninat be <^apable of 
being made lo coincide by rotation in tbe plane of tbe |»per ; thai 
is, they must be identical, yor, if tbis were not tha case, two enan- 
tiontorphiiua coiilI|i:uratii>ns — tlie fomuU aod Its mitror-lmage-^would 
b« pOMlble. wbllo for intntniolocnlar compensation oalj one oonfl^- 
mtioo is possible. 

Tbe BboTo reasoning may be applied lo the dctennmation of the 
stereochemical stmotare of arabinoee. Eight alereowoDMric fonDuIn> 
arc [Miitsiliie for a pentose, but, by arranging these In pairs of mirror- 
imngm, and talcing ono of each pair, four different typn are obtained : 



STEREOCHEMISTRY OF THE MONOSES. 



871 



H — 

H 



CHjOH 



H — 



— OH 
-OH 
-OH 



H 

H — 
HO 



CHjOH 

— OH 
— OH 

H 



C^ 
^O 



Ah 



H — 
HO 
HO 



CHjOH 



— OH 
H 

H 



H- 



CH-OH 
OH 



HO — 
H — 



o§ 



— H 
— OH 
,H 



u 



in 



^0 

rv 



The mirror-image of I \i represented oa p. 270. 

ArabinoBfl in oooverted by oxidation into an optically aotiTe tri- 
bydrozyglutario aoid. Tbis excludes tbe tribydroxyglatario acids 
wbich could be obtained from types I and IV, since each of theca 
could be made to coincide with its mirror-image, and thus would be 
optically inactive : 



H- 
H- 

H- 



COOH 



-OH 
-OH 
-OH 



COOH 



identical with its 
mirror-image, 



HO- 
HO- 
HO- 



OOOH 

— H 
— H 



COOH 



H- 

rv. HO- 

H- 



COOH 



-OH 

-H 
-OH 



COOH 



TTO- 
identioal with its u 
mirror-image, -ac\ 



COOH 



-H 

-OH 

-H 



COOH 



The fact that hg the aid of tbe cyauhydrin synthesis arabinose can 
be converted into a mixture of glucose and mannoae, wbich on oxida- 
tion yields the optically active saccharic and mannosaccharic acids, 
enables a choice between types II and III to be made. Since in the 

■a ri 

cyanhydrin synthesis only the group C" in CHOH-Cq is altered, the 

conflgaration of the rest of the C-atoms remaining unchanged, sao- 
charie acid and mannosaccharic acid most have tbe stereochemical 
structore 



COOH 



H- 

H- 

HO- 

HO- 



-OH 
-OH 
-H 
-H 



COOH 



COOH 



or 



H- 

H- 

HO- 

H- 



-OH 
-OH 
-H 
-OH 



COOH 



tja 



ORGANIC CHEMISTRY. 



if arebinosG in repreMOtHl by fornmla II. Neither of rhese cnn 
QUtde to coiiii^idfi wicb its mtrmr-imasQ, so thai formula II is umiB 
to mprfjiGnl MTnhlnoM>. FnrniiilA IH u picluded, bIhoo iU aiuimpda 
wonld DKC^iinti; thiti oiiu of the aoidjt meDtaoRed nbore ahould tuiTe 
tlis itOEMobemical constitution 



COOH 



H— 

HO 

HO— 

H— 



-OH 
-H 
-H ' 
-OH 



COOU 

vlilota li MontkAl mi'h its mirror-iinagQ: one of the acids vould tlien 
be opliciilljr io!U!tiTO, wliicli ia not the case. 

Ariibiiiosc liiw, thereforo, « formnta of tlie type II, but il is (llD 
uncerinin nhoihcr it ahould tw repreitcutod by tbo formula givflD 
above, or by its mirroNiuuige. 



XL DIMES 

215. Numerous rfwMM <or hiosc») are known, which are almost 
exclu^vcly derived from hoxtisea, aiid therefore have the EormuU 

C^H^O., = 2C.H„0, - H,0. 

No (Jioses arp known whk-h can be decoinpoBcd intx> a pentose 
and a hexosu; on hyiirolysis, some of thu hexodlcuctt y'w\A twu dif- 
ferent rnoiiitscs, and some only one. 

Thi! hydmlysis ran be effectwl not only by ImhIuik with clijiitc 
acids, but also by the action of enzymes (828). On account of the 
readiness with whinh decomposition with water takes place, it is 
assumed that the mnncKqcK from which n dioRi' t» formed are not 
linked together tliroiigh tlie carbon atoms, hut through one or 
more oxygen atoms. 

Up to the present, succeni in the att^'mpt to synthesize difid^es 
from monosos has been confined to the case of maltose; Croft ffti^ 
found that maltose is produced by the action of an ensv-me called 
taailatt {222) on a eoni-ciitrali'd solution of glucow. A« this 
eniyme is al^ able to ^plii tij; maltose into glucoae, it is eTideut 
that an equilibrium mu^t be reached: 



c»u„o„ + H,0;ir2C,H;A 



firOSE AND LACTOSE. 

The besVknoym dioses, siirh as sumnie or cano-sugar. and larlotce 
[,t>r milk-dugar, have aot ytt bccii prepared syDtbctically. 

Maltose. 

^faUMe in the en-sialJizod state has the formula C,jH„0„ + H,0, 

J«id cnn l>p prrparwi from .starch by the action of diastAso (47); 

litis an important intt^rmediate product in the industriftl produc- 

•tiun nf alrnhnl. 

MalTosf cryst*llizes in small, white netdles, and is strongly 

I drxtri>mt*tor}'. When lioiled with diliitr mineral acids, it yields 
only d-^lucotc. It exhibits all the characteristics of the nionoses ; 
thus, it reduces an all<aline copper solution; yields an osazone. 
moKosaione, (C„H„0„ - 2H,0 - 2H + 2C,H,XH ■ NH,) ; arid it can 
bt oxidized to the iiiounhHsic /»ifi/(n'»i'»Ki> nnVf, C[,H„0„, whieh, 
fin hydrolyaift, spHtis up iiitii (/-glncnsr' and «/-glTicon:c acid, 
CH,()H-(rHOH). {.'(>()H. 

These properties sJiow tliat maltose contains only one of the two 
earhiinyl-groups present in two ciiolec^uleti of (/-|u;lui;uHe ; thus, it 
yieltia aD osantme with two. inatt-ad of four, molecules of phenyl- 
hydrazine, and u inoiioliaaic insitad of u dibasic acid. The Unluii; 
of the two muWuh-a of (/-kIucosl- must, therefore, take place in such 
■ way tliat the carbouyl-oxVKCu of ouiy one molecule enters into the 
reaction. A union of this kind between two monwe molcflulej* is 
called the monoraThnntjl-Uond. If this is denoted l>y the sign <, and 
a free carbonyl-group In a raoleculR by < , then maltocse can be repre- 
eent^dby 

OHi.O, <oc,n,A <. 

uluoine OluiMM 



Lactoie or Sfilk-augar. 

816. iMctose in prrM-nt in milk, and is prepared from it. 

\Mtey is iisiiaU> n(Ui>l>;y«d for Itiia pur[io!ie ; it in tli« liquid which 

romainfl after llio cnjain hut bo«n separnled and tha Hlclmiaed cntlk 

j^bas lx!i:n used for waking cliocso. In thono procensca Ifaa milk ix 

uprivu^t of most of its fats and nlbutDiiious substau(»!«; ttic wbej 

tntaias Dearly all tho lactwc, and a large proportian of the roineral 

'eonMtluents of ttie millc. The lactose Is obtained by evaporation, and 

purified hy rccrjittJilIiLdtioii. 

Ijietosf crystallizes in well-defined, lanp% IiarJ crystals. It has 
kot such a ifwevt ta^tte as sueri>.-<e, and in the mouth resembles sand. 



274 



ORGMNIC CHEMISTKY. 



OD account of the hardness of its crystals, so that it is sometimes^ 
called mnd-syigax. 

Od h}'drolysis, lactoee splits up into i/^alactosc and (^-glucow. 
It shows the reactions of the monoses, and can be proved, by a 
.method analogous to that einployeii for maltose, to contain one 
. free carbon yl-group in the moicculie, so tlmt it is a combination of 
d>^ucose and if-gslactoee, linked by a monooarbonyl-bond. The 
free corbiinyl-gToup iM'toiigK to the rf-gliimse molecule, since lad- 
ose is cnnveii-wl by oxidation with bniinine-watcr into lactohionic 
acid, which is split up by hydnil.vsis into d-galactose and d-gluconic 
acid. Lactofic is, therefore, rcpresciitcd by 

C^„0»<0-C,H,A < 

■UlaUvtOM li-Uluoow 

SacroM or Cane-su^r. 

?17. Sitcroee (sacchoroso) is present in many plants, and is pre- 
pared from Kiigar-lK-et and sugar-raiie. It pryslalliiies well, and is 
verj' rcwlily snluble in water. Jt melts at 360", and »nlidifit>s on 
cooling to an amorphous, gIa.-»>liko ma-ss, which aftrr a considerable 
time becomes cryatalUtie, ^l^■hc^ Ktrongly heated it turns brown, 
being converted into a siibstance called caramcL On hydmlysis, 
sucrose yields rf-glucose nnd rf-fniptosc in equal proportions. This 
inixturois cAlIcd inv€rt-t\iQar,&.i\A is Ificvo-rotatopy, since rf-fr\tctose 
rotates the plane of polarisation more to the left (212) tlum cf-glucHse 
does to the right. Sucrose itself is strongly dextro-notatorj' . so iliat 
the rotation has been reversed by hydrolysia. This is colled iViitit- 
turn, a term also applied to the hydrolysis of other diosc^ and of 
polyoses. Sucrose does not show the reactions characteristic of 
the monnses; thus, it. does not mduce an alkaline cop)>er solution, is 
not turned brown by eanstJc pota.<;h, and does not yield an osaaone. 
Hence, it is evident that thrre are nn free carbonyl-groups in its 
molecule; it may, ihercfon-, be ctmcludei^l that iHtth of these have 
enierctl into reaction in the uninn of the two monosrs. Such a 
linking between two muiioscTs is called a dicarbonyl-hond, ami is 
represented by the sign <0> ; so that sucrose is 

C,H„0, <0> C,H„0,. 

216. The discovery that alcohols are able, under the influence of 
hydrochloric acid, to unite with raonoses with elimination of water, 



SUCROSE OR C^NESUGAR. 



*7S. 



affords an insight into the nature of tlie monocarbonyl-bord and 
ihf dicarbonyl-bontl. Thi- substances thus formed are tailed glueoa- 
iiles, jdnce thvy are in iiiaiiy' ways analogous to the natural glucw- 
ides, siibstariees which are sjJit wp into a siipar, and one iir jnore 
compounds of various kitids,on Iwuling w-ith dilute adds- The arti- 
ficial glucosides arc obtaintnl by the action of one molecule of aa 
alcohol upon a uiouosc : 

C,H„0, + CHjOH = C,H.,0.-CH, + n,0. 

These compounds vrem discovered by Kmiu Firtciiiiit, who has 
ossif^d to them a cotujtitutiun analogous lit some rcapccls X<j that 
oftheacetals (113,2): 



^^P HJOCH, 

Aldnliyd* + Aloaluil 



AcbUI 



In tho formation of glucuside, only one molecule of alcohol acts 
upon the aldose, so that one of the liydroxyl-groujw of Uie latter 
playn the partof a WT.ond alcohol oiolccule: 




CH,OU 

CHOH 



yCHOlH 
/?CHOHj 
aCHOH 

C! +H 

H 



CH,()H 
CHOH 



;9CHOH 
aC HOH 
OCH, 6-OCH, 
H 



The grounds for the aasiimption nf this constitution arc: first, 
these glucasiiica an- readily split up int« their components, wliich 
argues against the cxinti-ncc of a carbon bond Iwtween them ; second, 
the hydroxyl of the >'-C-atom ia aesumcd to Ix; the one which reacts, 
wnM other compounds containing the group — CHOIICO — do not 
yield glucosides; the a- hydroxy 1 -group, therefore, does not react. 
Tlie j'-hydroxyl is, moreover, the most likely to onter into rcaetion, 
«ncc a number of instances of similar behaviour are known, such 
as that of the lactones. 

The combination of two monosca with elimination of one mole- 
cule of water may be represented in a way analogous to the forma- 
tion of a glucu^de froiu an alcohol and a uiunose. Maltose and 




^^ 



ORGAMC CHEMrSTKY. 



lactoee, which are united by a monocarbonyl-bond> and contain 
WW free carbonyl-group, are combined thus: 

CHjOH CH,OH 



CHOH 



I 



oGHOH 



+H 



(CHOH), 
OCH, 



CHOH 
CHO— 
HaO + CHOH 
CHOH 



a 



O 



(CHOH), 



The constitution of cucrose, in which fructose and glucoee ire 
united by a dicarbonyl-bond, may be sho«ni in an analogous way 
tobo 



CHjOH 
CHOH 

CHO— 
CHOH 
CHOH 

c ■ 



CH,OH 
yCHO— 

/9CH0H 
gCHOH 



^\ 



cir,0H 



Snnmse forms fltimpoiinds with bafiCA, called sacpharates ; 
among tht-m arc C,iHaO„CaO SHjO, and C„HnO„-2CaO, which 
are rewlily soluble in wator. When this solutiun h boiled, the 
nearly bisoKiblc tricalcium saccharate Ci3Ux,Ot,-3CaO>3B,0 is 
precipitated. 

UanufactDre of Cane-sugar. 

219. Sucrose is present in solution in the cell-fluid of the 
sugar-beet and sugar-cane. The cell-walla arc lined with a thin, 
cotitinuoua layer of protoplasm, eoiiitiitutiiif; a 8eini-i>enncabJe 
ruembranc (13), whicli pre\cnts the diffusion of the sugar from the 
cells at urdinarj' leni|)eralures. When placed in water at 80*-9CP, 
the piMtopia^iin is killed, coagulates, and drvelops minute rup- 
turta, through whidi the cell-flukl can difTuse. The prooeea 's 
facilitated by cutting up the cane or bttt into pieces 2 to 3 mm- in 
thickness. In order to nialvi' the diffiisinn-priipesa as complete as 
possible with a niininium amount of water, the slices are placed in 
vats throiigli which water eireulatep in such a way tliat the neariy 
exhausted material is acted on by fresh water, while tliat. which la 



CANE-SUi 



only partly cxhausW'4 ooni<'s into contact with the solution already 
obtained, so that the material richoal in .sugar is treaHnl with the 
strongest extract, and vice ittmi (prinoi[)le of the eoimter-ciirrent). 
In this way. a 12-15 per cent. siigar-Rohition is obtainefl, which is 
about the proportion of sugar contained in the beet itself. 

Slaked litne is added to this solution, whereby a double object 
is attained. First, the free acida in the sap, such as oxalic and 
citric acidjt, are precipitatwl, along with tiit' phospliates; i\\v removal 
of thesi' is tiecossary, aiico they would eaiiso inversion on conoeii- 
trating the solution. Second, albuminous and colouring matters 
are precipilaled from the solution. I'or both tliese purposes, it 
is necessary to add ati exwes of lime, part of which goes into solution 
a-s saccharate, which ha.i to be ilecomposed by a current of carbon 
diftxiile, care lH>ing taken Xn leave the liquid faintly alkaline. The 
pmei|iilat*' is t^eparaUnl by a fUter-prvsH, and the liltrate cunceii- 
Iratf-d. In imler lo obtain Ihe luaxiinuni yield of augar.lt is n*ce 
»ary (hat lliis nfticent ration should lake pUice at a low temperature^ 
This is attained by the use of vacuum -]>tuL^. in which the sugar- 
wlution boils under diminishwl pressure. The first product of the 
concentration is a thick syrup, tnoro strongly alkaline than the 
original solution. Calcium earbonate is precipit«te<l by repeated 
treatment with eniboii dioxide unii I ihethiek syrup is almost neutral 
after which it is filtered, and concentrated until crystals of .stigar 
bejpn to separate. The solution i« then allowed to cool, when 
more crystals are obtained, mixed with a syrupy liftuid, whicii a 
removed in a centrifugal machine. This syrup is further crr's- 
tallized by slow agitation with a stirring-apparatus, and the crystals 
are again separated by meaut^ of the centrifugal machine. The 
syrup tlius obtalued (molasses) is worked up for the preijaratton of 
B aJcohol. 

H The cane-sugar ♦hus prepared is not pure; it is brown, and cou- 
Hloins a ctrtain amount of syrup. The crude product is purified by 
HiliMiolving it, demlnurizing with animal charcoal, and couooD- 
"trating in vacuum-pans. 



I 



Qnantitfttlve Eitimation of Cane-iogar. 

SSO. Tlie great pra<*ii(!Ll inijMirlance of cniie-Bugar makes it 
[desirable to liave a quick and accurate methcKl of estimating it 
Ujuantitativety. This is aliuoat exclu-sivety done by exa.miiiing its 



>78 



ORGANIC CHEMtSTRY. 



aqueous Bolutlan with the polarimctcr (87, 2). Since Tncrosc il 
strongly dexlro-nitalnr}' {{a\„ = + Cft-n"), a stnnl! qu&nlity pro- 
<hices Hii appreciable amuiint nf rutation. Thin ih almost inde- 
pcn4leiit nf iht; tcnitjcraturc, and for prat'tiral purpdse* may be 
cnnisidfn-d u» strictly pntportiDnu! to the concent ration. It ia 
obvious that thitt jnttbod wiU only yiirld accurate resultfi when 
no other optically active substances ore present io the aolutioa. 
If such aiibstaneca are present, either they niusi be removed, 
or their efifeel taken into account. The former method U adopieil 
in the determination of the amount of aigsr in beet. The sample 
jfl grated witli a fine rasp, to destroy the cell walls, and a weighed 
quantity of the product is made up to a certain volume wilb cold 
water, whioh dbeolves not only the sucrose, but also optically 
aetivn alhiiminouH substftnceR. The latter are preeipitateiJ with 
lead aci'tatf?, filtiTcd off, and tliu amount of rotatiuii obser\'e<l. 

When another sugar is present in the solution along witti the 
sucrose, it is nt'crei."iary to proct-rrl by the fcetmil methnd. Siip- 
podng gliiGonc iti also prcM^nt, the- rotatory power of tho Noliition, 
which will Xw. ilcxtro-rotatorj-, vf- dctemiinccl. If it be now inverted, 
the solution will either diminish in dcxtro- rotation, or will become 
Ia?vo-rotatorj-, sinee in\'ert— 'iiiRar is Ifrvo-rotfttori.'. The rotatory 
power of an invert-sugar solution obtainecl from a sucrose solution 
of giveu strength being known, th^se two (*bserA'ataons fumii^h the 
data by which the percentage of glucose in c&ne^ugar can be 
easily calculated. 

Teloaity of InTersion of Snorou. 

S21. The equation for uiii molecular reactions (101) may be 
applied to thp inversion of a diliit<r solution of sucnisc. If the 
original atnonnt of the latter pn-jwiit was p, and after a certain 
time the quantity x ha^ been inverted, then the velocity « tn the 
fraction of time immediately following, can be expressed by tlic 
equatiou 

dx 



dt 



k(p-x), 



in whioh ft is a constant. The inversion can be effected by meane 

of different acids, upon the nature of which the \'cIocity of the reac- 
tion is dependent, so that different values an? obtained for the veloc- 
ity constant k. When the values of this constant, and of the clec* 



38o 



ORGANIC CHEMISTRY. 



tion is inseparable from the presence and propagati»m of )-eai;t- 
cellfi. If it were found pnsBible U) tiring alKtut fcrniPiitatian withoul 
tbeir presence, this throrj" would fall lo tiir Kntuiid. KuuAiut 
BucHNGR has recently effected i\m. He trittirtttiil frcisb >'ca:<t with 
eatid. whereby the ixill-walls were destroyed. The dough-like miss 
was subuiitled to great pressure, which expressed n liquid (German, 
PrcKMajt) ; this was si-paraled by filtration from the cells stili float- 
ing ill it. BucHNKR |iri)veti in variuiii* ways that this *' press-fluid" 
caiitaitiK neither livinn: cells tior liviijy proluplasiii : for iiiitiattee, ihe 
yeast niay "be first killed by bringiiiK it into a mixture oC alcobi^ 
and ether; the pre^^is-fluid fmiii this euii nevertheless set up 
active fL-niiciitutioii in a solution of sugar quite as well as wbui it 
was obtained from li^-inp yeast. The fermentation is oaused by a 
dissolved Riihstanee, which, nn atToiint nl it.'< pmpertiefi, such ^^^H 
coagulatifm on warming, must 1h> rlu!«j>f>d with nlhununous bodi^^l 
it iit a kind of <^zyine, In which Hucmnkk has given the name 
zymfiifc. The yciiatM-elb only ha^i' the furit^tinn of produring tymaat. 

The rheiiiical structure of the fuzynurs is Btill wholly unknuMiL 
Meet of thcru have not been obtained in the pure state. Thar 
power of splitting up and deenmposiiig eompoundi^ is atno not under- 
stood. Hitherto, only !vnmll insight ha.s ix'en obtained iiitu the nn- 
diliona upon which their action depends. 

First, the ensynies only act at the ordinary, or at a Rlixhtlr 
elevated, teinperatiire; Mow the freezing-point their arti\-it>- is 
suspended, but returns at the ordinary- temperature; on bc«tti^ 
they are deconipoaed. Second, they are sometini<>s rendered inac- 
tive (■■ poisoned ") by the presence of stiiall ipmntities of cenam 
substances, such as hydrocyanic acid. Ttitrtl, it is ven- icmaifc- 
able that a given enzyme can only produce changes in a few m^ 
Btannca* and has no artioit on oilier similar compounds. That, cl 
the Afferent monosce containing two tu nine C-atoms, oohr the 
trioses. hexwws. ami nonoses undergo the alcoholic fermentatiiK: 
in fact, these are the only onea which, according to their ft 
can be readily converted into CO, and C^ti^OH ; far instanoe 
C,1!,0, - C.HjOlI + COr 

Only the monoscs are capable of being fermentea af 
dio^-9 mu8t firo't be converted into monosce. Yeast cxmi 
enzyme, inveftase, which first splits up sucrose into fmcioer 



FERMBNTMTlOyi AND THE ACTION OF ENZYMES. 



38l 




ghieoee^ This ts proved by the fnct that certain varieties of ycaat, 

L which do not rnntaln invertase, are intrapabtc of fenncntiiig 
Bucrose; thus, Bkykhisck discovered Schizoioceharoimfcea octoa- 
pana, which can ferment mftltose, but not sucrose. This variety 
of yeast contains no iiivfrta.«*, but nialtase, which is the ensyaie 
^ by which maltose is hydmlyzed. 

The property of being split up by enzymes, posseesed by the 
has been proved by Emil Fis<?her lo Ijo intimately i-un- 
ith their stereoclioinical L-diifiguratiuii. The three naturally 
occurring sugars, cf-glucose. rf-nianiiose, and d-tructme, are capable of 
undergoing fennciitEitioii, and there is a ^r^'i^t eiiiiiluiity in their 
configurations, since they differ only in the grouping round two 

Il-alonie: 



H — 
,H0- 



O 

— OH 
H 
OH 



H — 



C^ 

^ 



HO — 
HO- 



— OH 



H — 
H — 



CHjOH 

AJUueam 



— H 
— H 

— OH 
— OH 



HO- 



H — 
H — 



CH,OH 
CO 



— H 
— OH 
— OH 



H — 

HO — 

HO — 

H — 



,H 

O 



— OH 

— H 
— H 
— OH 



CHjOH 



CH,OH 
d-VnwUMM 



CH3OH 



^irari 
po 

I 1.^ 



rf-Galactose, which is also a natural product, hue a somewhat dif- 
'«rent configuration, and is either more slowly fermented by certain 

'icties of yeasi, or not at all. Tlie mirror-iinages of these eoin- 
pounrls, /-gUiCfise. etc., an- not capable of undergoing fermentation. 

The cause of these phcmirnena is probably the asyiiuiietrir strue- 
re of the etizyrnc molecule. Although Unwr si 1 list an res have not 
"been obtained in the pure state, their great resemblance to the ulbu- 
mins, and the probability of their fonnation from them, tvndcr 
their optical activity undoubted ; that i.^, they are to be- looked upon 
as built up of aiymmetrieninleculr^K. 'Hiis has led to the hypothesis 
that there must be a resemblance in molecular nonfiguratinn lietween 
the enzymes and the siibataiiees which they dccompre*ei and that 
when this reeemliianee is wanting, no reaction can take plaer. Kmil 
iecSKR appropriately compares this resemblance in glruciurc to 

,t neceasarj' between a lock and a key, La order that the latter 
may pass the luek. 

The application of the»e views to the chemical processes which 
go oa in the mure lughly developed organisms, leada to the coocep- 



■tha 




9tl3 



ORC/tMC CHEMISTRY. 



lion that generally in reactions ui which proteVd bodies act. as is un- 
doiibl^'JIy the case in the pruluplasm, the ronligiiratioii of tlie 
molecule has the same importance as its structure. Varioiw plie- 
Domeiia tnay be thus explained : Ihc sweet ta.st« pd^acssed by one of 
the optically active asiiaragines, and the absence of taste in the 
other; the different amount to which the three stcreoieonicric 
tartaric acids are oxidixed in the body of a dog fed with them ; the 
fai't tliat, («i snbcutaneoiiK injecti<in of a rabbit with /- or </-ftrabi- 
ntwe, of tli(> fiDit only 7 [xr ci!nt., <if the latter 36 per cent., is 
excretcxl from the body unchanged in the urine; and so on. 

223. Investigation of the stereoiffoineri^in of the mcmoees has 
contributed t<jwanl« explaining why optically activ'e bodies are 
formed in plants, whliet Ifiborator)- sj-nthesea usually produce the 
raconiic forms. It h&s been shown that tim h not tJie case in 
arcifioial syntheses elTeetod with compounds already having an 
asymmetric structure. Mannuse, for example, yields maimuhept- 
onic acid by the cyanhydrin synthesis, and it would be expected, 
from analogy with other cjanhj'drin syntheses, that equal quanti- 
ties of two etercoiHomeric mnnitoheptonic acids would be formed. 
This is, however, not so; onlj' one acid is obtained. This shows 
that the builduig up of a molooulH fnim one which is as\'mn](>irio 
can continue in an asymmetric sense. Sup[K>se that mannose is 
converted into mannononosF by three n'|Maitiuns of the cyanhydrin 
fiynt hi'.si.s, this always going on in only one diri-ction. This nomwe 
might be cu])ablc of bcinK split up into the original hcxosc and a pro- 
duct coDtaining three carbon atoms; the latter should then be 
oplieally aeti\'e, and on^ optieathj active molecule vxnUd haiv oc- 
casioned the formation of aiwOitr. 

The formation of sugar in the plant has liecn proved hy vege- 
table physiologists to take place in the rhlorophyil-grains, which arc 
composed of optically active stibstances. It may be asaumcd that 
the production of sugar results from a combinatioa of carbon dioxide 
. or formaldehyde with these substances, whoso asymmetry has the 
eifeet of making the sugar formed by eoodensation aUo as}-minetri«. 
As the other sulwtanoes which occur in plants are probably fonned 
from sugar, their optical activity is easily understood, «nce they are 
formed from optically active material. 

This by no nieons solves the problems of how the first 
optically acUvc compound arose, and of why nature has not pro- 



STARCH. 



»8s 




TiQ. flB.— RicR-ATARCH, X 8*J. 




Flo. M.— POTATO-BTAHCIl. X MO. 



>84 



ORG/INtC CHEMISTRY. 



which is the fonnula dtxiucod from tbc results of analysis. Oa 
hydrolysis, nearly all t)ic[)olyo5es yield monoscenitb the same num- 
ber c)f C-atonis, but a pfilyose which can be split up iiiU) pentose 
and hex«K<-o seems to be present in the guim of plants. 

Starch. 

926. Starch is the firat observable aasimihition-product o( plant 
It opfurs ill largt? (]iiaiititii!S in the tubers, roots, and seeds of 
many plants, in wliicli it is present tn the fomi of granules differing 
in fomi and size in different plants. Tht-se arc represented in Figs- 
67, 6S, Bud 69. 




Fio. ST.—UvK-nTAKtii. X SSO. 

Starch is insoluble in cold water: in hot Vi-aterit swells up with- 
out dissolving. It yields an intense blue colouration with & dilute 
solution of iixiinc, for whirh this reaction ser\'e8 as a lest. 'WTien 
boiled with dilute aeids, starch is wholly split up, >-iekiing only 
J-glucose, When Btarch-paRte is treated with diafilare, it first 
dis8olve», then the molecule splttji up, with ultiniatc formation of 
maltose and isomallose, C,iH„0„. Both these methods of treats 
ment yield intenmrtiiatt: jiroducts, however; these arc gum-like sub- 
atAUCttt, polyotsca cuntaluiug a smaller number of atoms in the mole- 



286 



OHG^SfC CHf-MISTRY. 



cule than stArch, callrd dcxirins. Dextrin is also obtained by 
heating starch alone, or 1o 1 10" with a email quantity trf nitric aciii. 
Starch docs net show any of the reactions of the monoees; it 
does not reduce an alkaline copper solution, nor resinify with alka- 
lis, and yields no compound with phenylhydrazino. This pmvrs 
the absence of a free carlioiiyl-gmup, so that i\s molecule must he 
represented by 

C,H,„0^<0 C,H„0,<0>C^,oO. 0>C,H^O,. 

It might be EUfi^Bted that the nioleonle of etareh funtains more 
thaa nn« dlcarboiijI-tjoiKi, when tlie fornmlik would be, for example. 

U.H.,0.<0 C.H,,0,<(.»L\H,.O,.O>t".H«0, 0&C.H,,0.< 

<0>C,Q„04.0>C.H,.0,.0>CiII,,0, . . . 0>C*H„O,. 

It does not, since b^'drolyais or a cAmpoiind of Uiis tjpo mtut 
j'teld, in addition lo (/-^lucoeo, it subsiniiCL* ^XMIkO. ~, coatainiug 
two froo carbonji-groups, nnd no such prodiicl liiu bc«n obtaiaed by 
the bydrolysifl of ainrcli. 

Dextrin can unite with phenyl hydmsin*. and exhibit* tho re*** 
tlons or till) initnoKes.Ruch m rvduction nf an alknliiK' copper «o1u1iOB,j 
and tito fornintion of a yvllow colouration with allctitit. U tniul,! 
therefore, bo nsaumod tu contain a (rue carbonyl-groupi 

manufacture of Starch. 

iXt. Tbi- prrwtM by wtiidi starch is niannfncturoi] is tboorctically 
T«ry siniple. When propni'od from potatoes, the latter are fiu«lj 
ground, so an to doatroy the cell-tissue mid lay bare itiestarch^graaulcx. 
Tbo latter are then treated with water in a specially conslrarii-d 
apparatus, soniewlmt rearnililiitK Hftiove, by niuNiia of which ibry are 
washed out of tlio ccli-tiMii», nnd fictile on standing, after wbicb thcf 
art carefully wasbied, and dricil elowly. 

Starch is rtupIoyo<) for many purposes in the arts ; as an adhesive 
pHAte, and for stifri^niD;; linen in luundri«s. In llm latt«r proceits, the 
ttareb-pasti- i*oonv«rted by tho hrat of tliosmoMhin^iron into a stiff, 
sliiniug l»yi.>r of dcictriii, f^onling tite fibres of the liuun. Starch is ol 
great iuip»rlnuc« ih n large oonatiluont of foods. It is tooru fully 
treated of in tbia coouectioii in pUysiulogical text-books. 



Olyoogen, (C,H„0,),. 

tM. 8t}fcogen is a «Qb«tanci! lufuiuibliug starch, and is present in 
the animal organtsm, the other poljoses Iwituc vegrtable products. It 
b usually prepared from Uxor, aud ia » white, atnorpboas powder. 



ceuuiosE. 



»87 



dinotving in water tnth foruAliou of an opnlwocol aoIuUun. Oa 
bjrdralyBis, it jridds ooiy (^glucose. Ai>parenll¥ Ibere are tiittemat 
liiadB of glyoo^D, varying with tlio ftQimnI (roni wbich it ia Uolated. 

CelliiloM. (C,n„0,),. 

229. Cellulose is a polyosc of very high molecular weight. The 
oell-walls of plants consist princi|)ally of this )!ubstiin{^'o, together 
■with liipim, which is probably not a polyo«?, Ccllukific is very 
stable towards dilul*' a*itls atid alkalis. TliiM property in tiiadt- use 
of in the technical preparation of cellulose, in onlt-r to fn-e it fn>m 
the substances present along witli it in the plftiit-niah-rial. 
iinrti, cotton, and paper consist almost exclusively of celluloec; pure 
filter-paper is neiirly rhemieslly pure cellulose. When it is dis- 
solved ill strong Kidphurio iicid, and the solution boiled, after dilu- 
tion with water, it is completely hydrolyzed. Cellulose from eollon- 
w(H>l, paper, etc., yields exchisively fi-glucosc; from cofTee-beans, 
cocoa-nibs, etc., rf-maiinosc. Cellulnsp is converted by treatment 
nnth fulphuric acid containing half in volume of water into a col- 
toidat modification, amylo'd, which gives a blue colouration with 
iodine; thia reaction funiiglies a te^t for cellulose. Tlio latter is 
soluble in an auunoniacal solution of eoppor oxide (Scuwritzeh's 
reagent); from this soluiion it is precipitated cheinieally un- 
changed by acids and salta, and forius an amorphous powder when 
diied. 

Tecluucal Applicatioos of Cellulose. 

SSO. Linen in olituiiint from llit! stiilk of Mik ItiLX-pItitit. The 1iu«ll 
flbros can be obtained from tiio tUi in scvtral ways, since csIIqIosc ta 
rery tiablB townnLi cbetnicnl rmi^^eiits ; thiE enu b« cfTected by immar- 
sion of lliu Hit! hi natter for iv period of ten days lo a furLiiijtiiL, which 
muiutt Difl deciiy of the oxtfirniLl fibre, giving rise to a vory anplRa&aiit 
smell. The process iskiinwii oh "Bleeping." The iliis isftpruid out to 
dry, Hnd is ttivn pasKoit lliroiigti corrugHtod "rullcira" tu looM'ii the 
externnl woody flhro ; Lho latter is slripited off by revolving wooden 
arms called " wipers," this Ijeing called "scutching." Tliu lin«n flbre* 
cno also be obtiviuf il from the llnz by the fiotfon at a very diluto sqIu' 
tlOB of alkali ; tlioy hitve a gray colour, nnd are bleached by eillicr 
being sproad out in the opoa, or by menus of blracbinK-pu*>'dor. 

^per was formerly prepared almost excluttively fntiu llnan rags, 
but is DOW largttly niauafaotune.! from wood and straw, which mtui 
bedividnl Inin fibre*, anil lhe<ie &i>paraud as much im possible from 
tbootber, ao-cniluti iuunuiiiig, ftubtttODces preoeut. Tbi» U etfeoted bj 



J 



sSS 



ORGANIC CHEMISTRY. 



the sulphite metliod, in whicli the uoud ia bcuted under piewure wilb 
asolQtloa c( ftcidsulphltv of cnlciuin. When Bimw is naecl, it is be«t«id 
with caustic sotLi utuler preuure. By Ihis process most of llial 
iacTuiitini; ttubsl aiices aiv di&aolvfd, (Lt tToo<J or slmvr being bleacheil 
at tbesaiiiu uiiie; Itin ci^llulot^ wtiich rr-tiutkiiH can tw roadily Bepkntt«d 
into flno fibres, which id uccosmio' lo 'lie maiiufBCturo of |»per*pulji. 
It b not. boweTer, pmuible to remove »U Ihe lignin by lliis praoesa, 
wilbtbv reHult that wood-paper and atrnw-papcr aunvrcr to the teats 
for ti^oiii, and can be e»ftily rf-cn^^ixed by means of Owee. Ug^nin 
gitOB a yellow colouration with suits of nnJline. and a red colouration 
nitb a solution of pbloruehicinol iu ouiiceiitrated hydrochlorJo acid. 

PurtJtineitt'paper i» prepared byconrorting the outer surface of 
paper Into amyloid (ZW), a process wbivli imparts toughness U> tlw 
paper. 

HltYfttM of CcUnloM. 

SSI. Tliew compouDdii are uf great tt^chnical importance. Wb«D 
ootlon-wool is tr«ated with a mixture of nitric and sulphuric acids, 
dlnitrates to bexan it rates are obtained. Ibis boing dependent u|)oii 
the concentmtion of the acids, and tb* daration of the i>roccss. C«l- 
ItUoae is ai^ilrarily Resumed tu bavu the formula CuBsiO,,, aotbnt 
to Uiedinitrate is aseigned Iho fortniila C.iII,.0.(OSOi)„ and to the 
beiaiiitrate CnHnOjONO,)*- The solution in a mixluru of akirtUol 
and eUier of ilie dinltrate, Irinilrate. and tetranitrate \i Viiown iis 
colltxtion, wbiuh on cvaporatiuii li^aroa an elaatic skin, nnd is vm- 
ploTod in photography. The hvxanitrntf inffuncotton, wbich looks liVe 
cotton-wool, but feels somowhal rough to Ihc touch, and is esleosirelr 
tinployed as an «splosive. It boms quietly wbem a looee tuft of it is 
Ignited, hut can ba mitde to explode by the detonation of a trniall 
amcnnt of mercury fulminate, and yields only gaaeotis producif, 
nitrogen, bydrogun, watcr-vnpon r, akrbon monoxide, aad carbon diox- 
ide. It «xerts a brimnt action (180). and without modification », 
th«r(«fore, unaiiitabio for use in nrliltcry. 

When guncotton is diMolre<i in awtone or ethyl acetate, a geUtitt- 
ous mass Is obtained ; after n'^nioval of the solvent, an amorphoua, 
transparent substance is left, hnving the same diemicnl vomposittoti 
im gtinoottnn, but biirnini; and eiploiling more sloivly. By ibia means 
the Telocity of expl'jsiun can tio so regulated as to malte gnui'oiton 
available for use in artillery, and it b employed in this form under 
the name ■ ■ aniokeless powder." 

The licxuiiitratu ot cellulose is also nsed ia the manufactiiro of 
artificial nilk. In DS CffARnowr.T's method, tlie nitrate is dissiilved 
iu a iniilnre of alcohol and cthur, and the nolution pressed through 
fino glass tubes under a prossare of funy ti> fifty aimo«|)h«ros. Tba 
fllamvnta are received in water, which takes up tho solreot, toanoc 



AMWODEifiyMTrt^^S OF ALDEHYDES AND KBTONES. a89 

Tcry fine thread ; when t«a to twenljr of llie«e are spun togL-thvr. « 
tbread mpable of being wotod ia oUftincd. WhiMi llie fabrio tlius 
preiwred i« treattxl with h solution of calcium iiulpliidtt, obuinnd from 
tlip innk-wiutc in tbo mauiifiic-tura wf Budium carbonate by Ihe 
Le Dla.nc procewiC' Iaorita.nlcOlieiiii»lry," 826;, the NOrgro'ips «t llie 
citrato are «ltmiiint«d, witb prwluution of DCurly pure collulo9» in ft 
form exactly reaeiubliEigsilk. 

AMINO DEBtTATITES OF ALDEHTDIB ARD KEtOlTlfl. 
SS2. Vt!ry ffiv rxnmplea ot tliis class of compountls are known. 

AmitmiwtaJd«/i^<t^, t"H,Nn,.c", axery uusUiUa eampottnd, MB be 

obtained from omituxuMal, CH.NH,.0,^w, „ , , whleh oan be pre- 

pcired tivm oioiiochloraacetal, CBiCl'CUlO0iU*>i. Htuoarim a pg»- 
aibl; the oorroipOLdiug trimettiylamiiioDium bue : 

CH,iNCH,),OH 
ig + H.O 

It is a orpita111n«, excMSlretjr poiaonoos substance, and ia preMOt Id 
certikin pUut«— for oxtiiuple, Load-stvul {A<furia*s muscariw). 

CliitUu is OUR of ihe |>riiicl[>al coiuttliur'diaof the shells of the Crus- 
tacea, suoli lis tlig crub JiudJobslur; whuu hvuled with hydrochloric 
add, it yivlda cfiitoMtnine fi^droc/iioridv, from wliicb the free biue 
diUotamirte, CiHitNOi, cau Ui ubtained by tho action of Rodium 
methoxidc dissolved inineiliyliikoho]. Chitoaamino undergoes achaiigie 
wh<iti ita solution in wethyl idcobol is boiled, since, on cooling, there 
graduiilly neimralbs from ilie lit|uid a crf.il>alline aubslancc, identical 
with /ructttMinine, whioh i^ slowly doveloped io a solatioD of fructose 
In metbj'I alcohol contatuiug auimouia. 





MM.COaH-4^ 



ariisckBiat ■iHtiii of the mnm of aldefavtlie 
Ktdi. It m y i iMMt ia wanpt tnmla^ and caa be pnptnd hy hrat- 
faie<BhroTHnae«dcaod.CHft;,-OOOH.arilh»ater. Itabonsaluu 
tbe oxidaitaaa a< aleekd vitfa Bitrie arkl, by the mrthod deaaUied 
nadergbrnzal (•>■). 

Ad aeai from the lofante pm^ abore. 0yoxvSe mad ccnuins 
one ronkcole of water, whkk aaaot be wrpvtted from t)M> acid ur 
Ita Baha vitbout thrir utfaiyMiig dMompotihjacL For tUs msun, 
Um wai«r b ofi«a aswmed to be in dmrucal combinatiao (158), 
CH(OU),COOH. ash H ta dikral h.nlrat« (MM). In both 

mbatancea the aldchTde-^^roup, — Cq, b umler the influence tif i 

atrongly negative grdup. — OC!, in chlonJ. aot] — CXX)H in fdyox 
Uc acid. The latter, moreover, posseaaes all Uh- prupertie» rharac- 
teristic of aJdehycIra ; it reduces an ammoaiacal silver Mlulioii, fomti 
an additinn-prnditrt with sodium hydrogen sulphite, fields anorime, 
etc. When bailed nith eaustie potash, it is converted into ; 
and oxalic acids, thc^ fonnation of which may be explained by ih 
nasumjitinn ihal one molircuU- tif tb6 umd takrs tip the twn hydni^ 
atotnu, tuid another the oxygen atom, from one molecule of wntcr; 
H*- H 



COOH.C + O + H 

^ u \ . o 



:coooH 



- OOOH-CHjOH + COOH-COOH. 

Pyrorftoemic Acid, CH.-CO-COOH. 

SS4. Pifroracrmif arid, the first meuilx-r of the eeries at ke 
acids, owTs its name to its formation by the distillation of ettl*f^ 
tartaric or racemic acid nith potassium hydrogen sulphate. 
Is {irobahlfi that carlvon dioxide in Bnit flplit off from tartaric vnl> 

jBGOt HCHOH CHOH OOOH. with formation of glyceric at^i. 

190 



PYRORACEMIC ACID. 



49* 



fCH,;o|n ■ C|H|OfH| ■ COOrr, which gives pyroracenuo acid by \asa 
of odc molecule of water; for glyceric acid itself is converted into 
pyroracemic apid by healing with pcitaKsium hydrogen Bulphale. 
PjToraceinie acid can Im obtaintii synlhc^tically by IiydrtJysJs of the 
nitrile formed by the action of potaKsium cyanide on acetyl chloride: 

L CH,.COa — CH,-CO.CN-»CH,-C0.CO^. 

TlnaiaageMral method, for the prfparalion of a-h:lonic adds. 

When heated to 150° with vHlute sulphuric aeid, pyroracemic acid 
Splits up into carbon dioxide and acctaldchyile : 



CH,.CO-|CO,!H - CH,-CjJ + CO,. 



f Pyroracemic atid is liquid at ordinary^ but solid at low, temper- 
atures; it iiiL'Its at 9", boils at 165°, and is ini^cible with water in 
all pniportioiis; its specific gravity is \-'Zl at 20", and it hafi an 
odour rc-sciiibliiig that of acetic acid. It ifi a strunjrer arid than 
propionic acid, for which A' is 0-(K)I:M; for pyromcemic acid K is 
0-56, which must be fixplaineil by nsHuniiiig the pieseiioe of a 
D^^tJvc earbonyl-KToup in juxtapoHition to the cnrboxyl-Kroup. 

»Pyroraeeuiic aci(i ha.s all the propertirs characteristic of ketones; 
it yields an oximc, a hytlnuione, an addition-i)rodiict with hydro-^ 
c>'iuiic acid, etc. 

TIio eleclroljTBis of a T«ry concentrated Rnlntion of pot^issiDm pfro- 

wXn yioltls nooiic acid nud diacctyl. Tliu formnlwu of acetic acid 

anst be looked upon as duo to the liitcractiuti of llie atiioo of llie ncid 

the hydroxyl-ion, after being di»c)inrgiHl at th« aDOd« : 

CH. -CO-COO' + Oir = CH.-CWJH + CO.; 

and that of diiicelyl as reeuItiDg from th« uaioa of tvo acid anions, 
witb etiminailon at CO*: 

Oul-Co'cSo' = l^H.-CO-CO-CH, + »00t 

The potaaaium salti of other kotonic adds arc decomposed by cleo 
Iroiysis In an analoj^iiB manner. 

AoetoBoetic Acid. CH, 00-CHjCOOH. 

238. AcdoaeHic acid is a ;y-kotonie acid. It is not of mueh 
Importance, but its ethyl ester, actXoaceiic eater, is a very interesting 
ooni}K>und. 

Acctottcetic ester is obtained by (Xaisen's condensation-method 




I aM»-cBr€aoc;B» 



TW 



«l tiK 



raft 

TW krtMW ilrnwuiiriliiw ■ •&n«l br 
Hf wlb dJMte ■^iihwii acid, ly with m <HMti 

, Hi* |Ww><m>*iBt atatum, fmrt»o» <ft)Pd>, — <i aleohJ: 

C», aj CIV CO,iQH. _ CH.-00-CH, + 00, + CAOB. 

Iht^atadJktmtS^^"'^ t>^ pla^ "^i™ ■cetaaeelie ester is 
hialcd vMi » wfy caocoiUmied aolBtioii of aloohofic pelarii or aoii«: 

*''+^i^+H^1§H' " CH.OOOH + CH,-CO0H + C^OH. 

The KR«i importence of oeetoAeetic erter for ayntheses arises 
tnm i(f capHhilHy of uiuli>ritMnK thrae two decotnimeitioiis, to- 
gether with t^H> laet that the Na-atom iti aodioacnnarctic ester 
oao bo nibilJtiiterl by a great variety ot groups. If it is replaced by 
a group R, llivrc b obtained the coinpoiiud 

CH,.CO.CHRCO<Xyj„ 



ACETOACF.7IC ESTER SYNTHESIS. 



m 



^hich. bythckptonp decomposition. yiel<Li a ketone Cir,-CO-CH,R. 
this n>acticm affording a gctu-ral inctlicxl of syntliesizing melliyl* 
ketones (110). 
H Tlie annpound cn,-C0-CHK-COOC,H, can b* converted by 
the acid dectimpiwition into acptic aoid, ami an acid of tlie romuila 
RH,C-Cf)OH, so that this is a general inethiKl of preparing luono- 

Ibatiic aci^ls synthetkatly. 
8udium can again react with the compound 



CH.COCHRCOOCjHi, 

with replacement of the hydrogen aloni H, and production of a 
compound wliose Na-atotii can also be exch&nged for the most 
varied groups, yielding substances of the type 



CH,-C0CRR'.C0OC,H(. 

( are converted by the ketone nr aeid decomposition into 
Cn,,CXJ.CHRU' or CHRR'aWH. 



■r 



On aecmint of this pro[)erty, the number of (^impounilR which 
ID bt- synthi-slz<d by the aid of acetoaci-tic i-ster ia v(t>' great, 
le pmei-si, <;ullrd tlie atrtotuxlic m((t syrUhcsia, Is (carried nut in 
JH- way ain;a<ly described for the malonjc ester synthesis (186). A 
*■ examples of this Bynthetical method may be mentioned. 
I, M Hhylnonjfl kftoitf, the princijial conatitiicnt of oil of rue 
(from ftvto gra\toif'ns), can be obtained by the action of n-octyl 
Jide upon sodioaeetoaretic ester: 




CH,CO-CH]Na + I,CJI„-»CH,-COCHC,H„; 

cSooCiU, coocyi, 

nd yields, by the ketone decomposition, methylnonyl- 

CH,CO.CH,C,H„. 

>ctyiacotoacctic ester yields, by the acid decomposition, capric 
arid, CiflH^O,, whoso carbon ehwn niuat therefore be a noniial one 
(144). 

■ 2. Heptylic add, which is obtainable from d-fmctose by the 
eyunhydrin synthesis (212, 2), can be synthetically built up from 
ar*--t<^cetjc ester by the successive introduction of a n-butyl- 




394 



ORGANIC CHEMISTRY. 



groiip and a methyl-group; this proves it to be n-butylmethyl- 
acctic acid; 



CH.COCHNa 

I 

coocyi, 

CH,.COCNaQH, 

I 
COOC,H, 



CH,.CO-CHC.H, 

COOCjH, ~* 

BuLjIaceloacvIii] eMer 



Urtti7l!>UtjiM(iMac(T(lc caur 

tluB yields, by the acid decomposition, 

CH.CH.QH, 

coon 

lletfajrl-n-bueylacvlio aold 

3. y-Kctonic aoids arc obtained by the action of acetoacctic 
ester upon the esti-iB of the a-halogen-substituted fatty acids, fol- 
lowed by the ketone decomposition: 

, R » K 

CH,COCH fNa X |fcH CH,.C0-CH— CH-CO,CA; 

CO^CjH, CO,C,H, ^^0,C,E. 

This yields, by the ketone decomposition, 

CH,-CO-CH,-CHa-CO,H. 

4. When iodiDo acts upon Bodioaoeloacwtio mt«r, the Bodiam is 
removeil, aud Ibe two riisi<luoB uuilu thus : 



CH.CO-CHiKii SftlHC-CO-CH, 

1 I +J'+ i I = 

CO.CH. CO,C.U. 

OHiOOCH CH-OOLH,-) 

+ 2Nal. 



co,c,n. 



10,0.11, 

iMoeeiylnwieiNt'c eMrr is rtirmoi, nnil, when tnjled with a 20 per oont. 
ftolntion of potassium CLirboimle. riMdily H|ilils off curboa dioxide 
aD(] alcohol, with formatioti of cuxtoitykuxttim (SOSJ : 



cn, • CO- cn— CH"- co ■ cii. 

lU I IT 



0,HJO. 



OH 



ICO. 



C.H, 

on 



CH,-OpCH,.CH,CO-Ca,. 




I«7iiliiiic Acid, CH,-COCH,CH,-COOH. 

236. Ltmndinxc acid is the simplest >^-kftoiiic acid; it can bo 
'obtAJned by the syiitlieticAl lui^lhod dcsiTiboii in 235, 3 — from 
acetoftwtic ester by the action of inonochloroucetic ertcr; in tliia 

I instance, in the fonnuU piveii R -= H. It was mentioned (212, 6) 
that licviilinie acid is proilucoil when hexnses are boiled with eon- 
centrated hydrochloric arid, and it is usually prepared by this 
method, which ha.s nut ypt Iwen fully explained. 
l..Eevulimc acid i? crystalline : it melts at SS'S", and boils with 
alight decompopition at HU)". It yielda an oxime and a hydrazone, 
and an addition-product with hydrocyanic acid; in short, it exhibits 
aU the reacUuus charactcmtic of ketuncii. 



HetoKalic Acid, C.I 



^ 



0, + n,o. 



H^ 237. Meeoxalic add is a type of the tiiheim'c krtimic acids. Ita 
constitution is proved by thp formation of <-f%' 'ncsoxalale when 

Idibroinoinalonic estcf, ItrjC(C(X)CydB)„ is boiled witii baryta- 
Water: 
Mesnxalic acid, like glyoxylir arid (233), ran only be obtained 
with one molecule of water. An ester of the anhydrous acid is, 
however, known; it vor>* readily adds' on walor. The constitution 
(a>")H),C(On)j must therefore be assigned t« thp froc add (166), 
,.n*hich has most of tht- properties of ki'toues. in the same way as 
lilf>ral liydratc (204) and Rlyoxylic aci<l show most of (lie rcao- 
Uons of nlilehydfs. When boiltii with water, rocsoxalic acid loses 
irbon diuxide, forming glyoxylic acid: 



(CgEi,OOC),C Hr, + Ba (OH), = (CH.IK.K;),C(()H), + BaBr,, 



^H-C(OH),-CXX)H. 



^ 



is not surprising that a compound containing a carbon aiom 
loAded with four negative groups should split up in this way; the 

Ificnmposition takes place more readily than that of malonic acid, 
hich does not low carbon dioxide till heated above its nieliing- 
ptMnt, to 140'-1.W. 




Hk 



a^S 



ORGANIC CHEMISTRY. 



OxiOafetic Eiter, C,H,(XX;COCH,0OOC^ 

. SM. Oxaia-Ylin titer c«a be obtained, ia AocordAiioe with Ci.usbh^ 
mollicMl (SOS), b} the ooDdensalJon of etbj*! oxalate witb etlijrl aaHlMXx r 

,ONa ^ 

C.H.OOC-COOC.H. - CB,OOC c(oC',H, +HCC0OCH.-. 



'\ 



tx;.H. H 



UbjMtxOM 



AddHkM-iinKluict 
wUb twlliim vUiuside 



Ethyl MMMB 



/ONa 11 1 

-•0,H,OCX;-C=CH.OO0O,H» -• CH,OO0-C0- ;CH,- COOC,H, 

Onl*o«Uo MUr 

OxjUlMtk Mt«r, liku ttootouixitic ester, ckh bo split up with addi- 
(Eon of oao molcculo of vrator; tb« iwo poiaU at irhicb ilecompocsiltDa 
eaii rivcur are iiidi<»tted in the formula by the doited lines 1 and II. 
Dilute salptiuric acid causes deooiii]>o»llion at I, nitli fornuitiou of 
pfmracoRiic acid (BH), carbon dittxldt*, and alcohol. Decompoitilion 
at 11 rcsuUs from tliu actiun of ulknlis, iitid yields oxalk' and neotic 
acidx. The. kctuiiic iialuro of oxalacolic e&ter is shown by tte fonno' 
tion of an oximB and by other reactiaiw. Fro6 oxalacetic add is not 
obtained by saponi ncation of the oster, tiDoe decomposjiion occurs. 
It can, how«Tcr, be nbluitmd othiTuriao; il;t iiivlts yriih dccompositioo 
at 173*. Reiliiutioii witli Hodiiitu aiiiiilgNiu yiolils riiiilie iicid. and this 
roaction, together with the syntbe&JA given aboro and the (oriDation 
of an oiime, eatabllshes the ooustiiution of oxalnoetio ester. 

Ac«ton«dlcarboxjhc Acid, a^OH- CH,- CX>CH,-O0OH. 

290. AcMontKlicarbtixylio acid is formed by tliti action of coocaa- 
tratod sulphurie aeid on cltri« acid, wator^vapotir and earboo ni»D- 
oxido being orolvwl: 



CU,.C(X)U 
-OH 



COO a 



c< 

en. -COOK 
CIlMeactd 



cn..cooH 



= CO 

I 
cii.-coon 

AneiotwdloMbosrlto lofd 



+ OO + HiO. 



Tills decomposit Eon la analogous In that andergoiw by other o-bydroxy- 
acidf into Aldohyd«. and rormio ncid or CO + lIiO at5'|. 

The coiistittilion of nctttortcdicarboxylic acid is inferred from its 
forming with hydrocynnio a«id an addition-product which is the 
inononitril« of citric acid. Foar H-alonu of aoetonedlcarboijIiQ 






'^J 



a 



C«' 



C0 



Of 

4U. 






C^a/ 



fAUTOMERiSM. 



•97 



i/fiapiVBMmMiy n^fia/OtA \>^ i^oA\\\m; this ig iMpUlnvi) ^>y ibe 
I IB the inotecale of two tDDtlirlcao-groupa in uuion witb 
iwgntivfl groups. It Is thus powdbls to introduce in sueccfisioa four 
(lilTerviit nuliolns, wliicli mnkes tliu formatioD of uuioorous deiivii* 
tivcs fe4isibli;. 

Aoelonedioirboxyllo ackl is cryslnll iiw, and mflw nl 1$5', with loss 
of two naolcculw of mrbon Jioxide. nnd tnntintioii of aet^tone. 

Vitij-Iacctic auid (1481 cad be obuiined by tlie aid of acelAnedioArb- 
ozylte acid. It is first Tediic«d to jS-hjdroxj'glutBrie ncid, wtioio Oil 
is then xiib»tStutc>(I by bromine by treaiuieiit witb conoentr-ited 
hydrobromte ndd- 

COOH-CH,-rO-cm,-COOH-.COOHCII,rHOH-CH,COOn^ 

Aoownnlicvboiyllc ocM S-Hf<1r«xyKluurlc achl 

-* COOH.t:H,CHBr.WI,-tXX)H. 

Tho Bodlam salt of the tatter displays the property oomnoD lo 
/9-tifllogcn-subsi ituted acids (ITS). o[ spliitJQg off NaBr and C0>; It 
thua yields tbe deaired vinyl&cctic acid : 

COO |j^ -CHfCH lBr) ^H,CO0N» = 
« NaBr + CO, + CH,:rHOH,-tX>OKa. 

Sodium TiaylBOelMa 



TAITTOHEBISII. 

S40. Ac«t.oacctIc ester, and in general such substancps as 1 : ^ 
which coritjiiii the group — 1'() — CH,— CX^) — , affftnl 
IibUiwps of a rrmojltiible kind of isunicrisni called tautoma-imt. 
impound* of this kind bfhnvc as IhotiRh they contained «ome- 
thc group namrd . sfHiiotitnrw thr itrmip — ('(OJ^)-CH — CO— j 
few exainplts will serve lo nialce this elearer. 
Wieii alkyl-groups are introduced into acetoacetic o«t*r (235), 
become united to a carbon atom: thus, met hy lace toat-etic 
r^ter must have the constitution CH,-CO-Cll(Clf,)-C(X)C^, 
aince by the ketone decompodtion it yields m«thylethylketoTic, 
and by the acid decomposition methylacctic acid, or propionic acid, 
^ncc it. has this coiiEtitiition, the formation of nif>thylnretoacetio 
Eld 18 best explainetl by tnippnaitig that KodioBnetoacetie ester, 
"CH,-COCHNaCOOr,Hj, is firat fonued, the N'a-.itoin being 
then exchanged for a ntcthyl-gmup by the action of methyl iodide. 
The majority of tsubsUtutioiui in aculuucctic rater a^c to be tooktHl 




t^S 



ORGANiC CHEMISTRY. 



upon as tttkitiK pluec in this way, with formation of C-derivativct 
of the cstflp. 

A different effect is produced by the interaction of sodioaocto- 
acclic enter and cMonjcarbonic ester, ClCO()C,H, (24fl), which re- 
Bulbi in the funnution of two auliistaiiL-i-s in different quanUttes. 
The one formed to. eumllcr quantity results by the reaction indicated 
above: 

CH,-CO-CH » 

\x)OC,Hs 

dnoe this substance is identical with the product obt^ned by the 
action of acetyl chloride on sudiomaimiic ester: 



CH, 0OCnN6-€O0C,H, 
+ Cl-COOCjHj 



CH,-C0C1 + NaCH(C00C3nj), -» CH,00-Cn(COOC,HJ,. 

Its constitution also follows fmm its solubility in alkalis, indieatiug 
that it contaiiiis an U-atom replaceable by metals. This must be 
in the Ctl-group. 

The main product uf l\m reaetion is on i»unieric oc»npound, 
which is assumed to have the cuiistituiion 

ai.C-.CHCOOCjH, 

on account of its motho<I of formation and its insolubility in alkalis: 
the latter proves that it does not contain a CH-sroup betn'ecn twu 
carboxyethyl-groups. The formation of a c(>m[M)und of this typo is 
best explain(>d by the iu«uini>ti()T] tliat oodiuacet^iaeeiic est^r has 
the coiistituliun CH,CC0\a):CH-C0OC3H„ as replacement nf the 
Na-atom in this by the group — COOC,H, would lead to the forma- 
tion of a substance of the above constitution. 

An analogous reaction takes place between chlorocarbonic ester 
and sodioacctylacetone; the process is to a Bmall extent in aoconl- 
anoe witli the equation 



CH,-00-CH 



+ 



Na 



CI 



+ Naa, 



■CO-CH, CH^'OCHCO-CH, 
■COOC,H," CO0C,H, 

«noc the compound formed is soluble in alkalis, anil therefore ron^ 
tains a CIt-group in union n-ith three negative groupe; vrhen 



TAUTOMBPISM. 



299 



warmed with nn equivalent quantity of caustic potAsh it readily 
splitjc u[) inUt p»ta»iiuui acttste atid acctoac<!ttc ofter: 



+ H 

CH.-cocn- 



OK 

C O CH, =^Cn,COCH,C0OC^nt + CH,C0OK. 



COOCjH, 
The niaiu reaction, however, takes place thus: 

CH,-C=CHCOCH, CH,C=CH COCHi 

I ■ = i + NaCl. 

ONa + C1-000C,H( 00O0C,H, 

This is proved by the infioliibility of the rompeimd in dilute alkalis, 
which split, it up, even at ordinary tcmpcratureBj into acctyiacctooe, 
alcohol, and carbon dioxide : 



CHCOCH,+CO,+C,HjOH. 



I 



CH,C=CHCOCH, 

icyjC^Hj = CH,-C(OH) 
+HOH 

This makes it> improlrabic that the gnmp — CCKXJiHj la in union 
with a carbon atom. 

When acid chlorides react with acetoacetic ester, it 13 possible at 
wilt 10 obtain a C-dcrivative or an O-iiprivative, that h, a com- 
pound in which the acid group is linked to the rest nf the molecule 
either through carbon or through oxygen. A C-derivalive is ol>- 
tainetl by the usnal method — the trealment of sodioacctoacetic 
ester with the acid chlorida. When, however, acetoacetic eater is 
tnixed with pyridine (386), and the acid chloride allowed to flow 
slowly into the (nL\turf, aii CMerivalivo only is formed: 




CH, CO-CHCXXlCjH, 



COCH, 

C*d<rrl«aci«« itoluijhi In alkalf) 



CH,-0-Clia)OC,H, 
O-COCH, 

OxlfrfvKttve |l"*uluUI« 111 alliKll) 



By moans of such ambipioua reactions, which chara<!tiTize many 
other subrttaiiee.^, it iis not possible to determine whether a body is 
a kHv-compriund, containing the group — CO"CH,'CO — , or nn 
enol-compound, with the group — C(OH):CH-C0 — . It was for- 
merly Ii|ni8l to a:isif;n one of the two formulae to substances which 
exhibited taulonierism, and to explain reactions not in accordance 
with this formula by assuming that Ininsfumiatiun had occurred. 
It 18 now known that « lautotncrie suUlancc, m th< liquid slatecr in 




300 



ORGANJC CHEMISTRY. 



soltUion, cmsisia of a mixture of Oic kcio-eompound and the owf-com- 
pound. the proporlton of each present bi'iii^ dc|«:inli-(il on cortaia 
oonditi'inp, and this vipw AfTnrdfl a salisfactory oxplaiialion of the 
observt'ci facts. 

The fundairicntal plienidnftgon i» (.hnl tmiinmers can roart as 
Llumglt llii-y coriMstc-d ivliiiliy nf the krlr>-cfmiin>mi(l, nr wholly u( 
the eriol-oaifipnuiul. This ia fxplaiiicd as follows. If, from a riiix- 
liiru oi two isoinors capuble of <:lmii;;mf; into oni; miother with such 
reailinesH timt the bnlaiuc bcTwcon thetn is rapidly rcstorw), an 
atl-(>iiipt is made to n>tnovc one of the coinpnnpnts by chemical 
m(!tho(U, the jH't'ond rompoiient should beroint? transfnnned itito 
the first, on arcoiint of the disttirhancr (if the rquiltbriiini; the 
iiuxtiire shtmlil then tract as though it nonBiHti'd wholly of llic fust 
componeul. If a chfiuk-al rraK<rnt which linly rearta with the 
second romponent is ii«m1. the mixture should Ix-have. for the 
Ranic n'asitn, as though the latter were the only substBiio(> present. 
It is, however, possihle to effect the separation of taiitomers l>y 
cheiiiieal ineans — lirst, when the disturbed bulunrc is only Klowly 
rcstopcil; second, by R-aclion» with nearly the same velocity for 
both forms, rcsiiltiiig in difTt-rent products. 

Tlii-iK conJilions nre lo a. ccrtnin extent nttniacd in the rciuitiona 
dvitcritiiH) on pp. 298 and 299 for chloruuHrboiiio estvr, SciiiFr cites 
anotltoi' example, llis addition oE beikz&lanilitic, C*l)(-N;C.'H-C4U», to 
aoeloacetic ester, which also yiehln two JBomeric suliatancM. It ia by 
no menoa certaiu wlii-llicr tlio pTo|wrtiou vf lhe>iaoment formed ia th« 
flftme as that or iIj« iioiionitiric fonm presmu in iha RcetoacclK? ester, 
WcauH it is unknown how far tho ubovc conditious ore fulftllod. 

Experience has shown that the enol-fonn gives an intense colour- 
reaction with ferric ehloride. whieh is not obtained with the kelo- 
form. Thijs gives a ready means of iitentifying a taiitomer, imd cf 
recogniKing the eonvennon of one form into the other; it has been 
applied in various instances', sueh as the investigation of fortnyl- 
phenylaeeliff ester. This siibstanee results, by Claisen's cooden- 
salion-niethod (203), from the action of the ester of phenylacetio 
acid upon that of fortnic acid : 



"^* Elhjl phoaylftreUtc Ktbyl fonnjrJptKiijlBMUl«(Eni>rronn) 

Rtirl formawi 4- 
•odium athMlJe 



TjIUTOMERISM. 



301 



The keto-form, or, in this iiislance, more correcUy, the " aldo-fonn/' 
of tills substance has the forniuU 



■ 






The enol-compound is solid, and molts gradually between 60° and 
70°; tho aldocompouiid is a liquid. In dilute alcoholic solution 
the former )ri\'e8 a dwp violet-blue colouration with ferric chkiride; 
the latter docs not give any colour. If, however, equally concen- 
trated Bolutiona of the enol-form and the aldo-form are made, and 
equal quaatlties of ferric chloride added to each, after some days 
the solutions are alike, the tint of the enol-compouad having beeoinc 
lighter, and the aklo-cotnpoiuid liaving developi>d a blue colour. 
This proves that after stanciing for an ititonal both solutions con- 
tain the aldo-fonn and the eiiol-fonii ami, since the tint i.s the same 
in each solution, in c(|ual anininits. It follows that an equilibrium 
between the opposite transfonnationa exists. 

Other inethoils are known by which this transformation of 
tautomers can be rL'cogtuite<l, of which two inay be mcnlioiied. 
Bruiil lias shown tliat rays of light an- nmeh nioru strongly dis- 
persed and refracted by Hubstaiiees containing a double bond tJiau 
by their isomers which do not contain sucli a bond. Since a double 
bond n-Jdilts from the t-noliialion of a ketivfonn, it is [xwsible, by a 
deteni dilation of the disjwrsive and refractive powers, to prove tluit 
in alcoholic solution enol-conijxjunds are trantiformed into kelo- 
compfMindK, ami vice rersa. 

W. H. Pkmkin.Skn.. haadiscovcrcd another aid to tlic invcatiga- 
tJoD of these traiisfim nations in the electromagnetic rotation of 
the plane of polariz.aiion. The plane of a plane-polarued ray, 
passed through a tulK> containing an optically inactive Ribstance, 
is rotatCfl when an electric current is passed thnuigh a win- wduiitl 
round the tulw, enrloMing tlie column of liquid. T\w valw of lliis 
rotation of the p!aii<^ of polarizaiion is eliarac:leristie fur ehemical 
compounds, supposing that (he current, and the length and tem- 
perature of the eolunui, are kept eon^itant: and Perkin found that 
subslaiices containing a double bond in the molecule occasion a 
much gn'ater niiigiietic rotation than their isomers, from which 
such a bond in absent. 



3o» 



ORGAHIC CHEMISTRY. 



llie iave?tigatioQ9 which have been carried out have ipvea an 
Inaght into the conditions upon which the kHitaiion of an enol- 
coiQpouiid, arid the ejiolization of a krt<>-r()mp€mii<J , n«pe<!tively 
dejteitd: aiiioiif; tlipni is thi> tcnipoj-ature. Cl.iis>:n found tliat 
acL'tyldibenzojlniPth&tn?, CH,(X>-CH(C(X;oH,), (beii3Mi,vI = C,H»C(). 
ej. 886), hna tlic kcto-fonn at onlinary tpinpc-raturcB. It is tlieii 
iiti$o)uhlc in alkalJH, and in aqtirnus finlution givns nu colouration 
with ferric ohloride. When hratM to 110°, ami quickly cooled to 
provenl irnmoditttc pc-trariMfonnation, it is found to be converted 
into the enol-form, since it answers tu the colour-test with ferric 
chloride, and is readily soluble in alkalis. 

It lias further been shown ihat the nature of the solvent has a 
gn^at influence upon thatranafomiatiou. Ju solution tii chlorafumi, 
an enol-fomi will remain unchanged fur niontlut, wldlc in alcoholic 
solution it becomes partly or wholly tr&i;9formed into Ibc beto- 
form in the course of a few days. 

pteoue sebttativeb. 

A number of compounds which are assiuued to cent ain the group 
CO 

HC/^CH 

II |l are known; some of these arc natural produeta. They 
HOy/C'lI 

o 

are called pyrone derivatives. Some of tlicm will be dealt with here. 
ChclidonK acid, CjU.Oo, so-CAlletl because it is found in 
Cfielidonium mujiia (greater celandine), funiia ctilourlffii aalta, 
CiHi(i,M,; it alwi yields yellow sails, C,H,0,M„ which are derivett 
from an acid C,H,0,, xantkochdidonic acid; this acid, however, 
when set fife frciiii itf salts, reatiily losft* one molecule nf water, 
being rernnvcrlcd int<» eliclidunic a<rid. By boiling with uikalis, 
the hitter is split up almost quautitativcly into tn'O molecules of 
oxalic acid and fme molecule of acetone: 

Otfcllc anld Awl (Hie 

These facts are explained by the structural formula 

CO 

HC/^CH 
HOOCCv yC-COOH 




Cbvlidoolc ociJ 



CHELIDONIC ACID. ^0% 

in accordance with which the acid can be called pyronedicarooxylic 
add. Xanthochelidonic acid must then have the structural formula 

CO , in which the two hydroxyl-hydrogen atoms 

are also replaceable by metals; or, in its tautomeric form, 

.CH,— COCOOH 
CO 
^CH,— CO-COOH 

The manner in which 3HjO causes the above-mentioned spUttilig- 
up is evident from the equation 



H, O 
,CH;C— COOH JCR C— COOH 

X) ^0 + 3H,0 = CO + ^^g 

\cH:d— COOH \^H C— COOH 

CboUdonioMid H, O 



Moreover, a synthesis of chelidonic acid corroborates this for- 
mula. The starting-point of this is acetone, which by Claisen'b 
method (203 and 235) can be condensed with two molecules of 
oxalic ester: 



,CH, CjHjOOC ■ COOCjHs CH : C < ^^^^s 

CO + = CO + 2C,HaOH. 

^CH, C,H,OOC • COOCjH, ^CH ; C< ^^^jj 



The product is seen to be an ester of xanthochelidonic acid. When 
this is heated with concentrated hydrochloric acid, two objects are 
simultaneously attained — the ester is saponified, and one molecule 
of water split off. These reactions yield a compound with the struc- 
tural formula given above for chelidonic acid, and identical with it. 



y** 



ORGMNtC CHEMISTRY. 



A pyroiie derivative wUicli has rfcciitly attract^^l attiaition is 
XH-CCH, 

do No . 
\;h=cch. 

It can be sj-nthesized from copjKT acotowHic fster and carbonyl 
chloride (849) : 



CH.OO COCH, 



CH.CO COCH, 

I 



CuCI,+ HCv ^ /CH 



HC— Cu-CH 

/ \ / x;o' \ 

CH,OOC +CI, COOCtH, CjH^OOC COOCjH, 

CO 



On saponification with dilute sulphuric arid, two molecules of cartwD 
dioxide arc eimulianeoiiKly elimina1«d fnmi the molecule, 90 that 



CH.CO 



«^\xx^ 



COCH, 

;h. 



ibould result. Its tautomeric form, 



CH.C 



HO OH 



CCH. 



U 



■I I 

o 



H 



homever, loan one molecule of water, yirldinfc dimethylp>'TOQC. 

Dimcthylp\Tonc i« characterised by the formation of additio«v- 
produets with aei<l8, which must be Iwiketi iiptm as Raliii. 
"salts" are formed by dissoivint; dinietliylpyrone in an aqii 
solution of hydrochloric acid, oxalic ari«l, etc.; the>- are ohtatned 
OTstallinc by the spontaneous evapnraiinn of thrar stilntinns. By 
^awJving tJiem in a lar^ qiianlity of water, they arc completely 
fayxlrolysed, so that it is improbable that the acid in them is linked 
to the carbonyl-Rfoup. Collie and TtrKi-E, the diseoverere of these 
oompoumU, accordingly assume the Mranitoiry »/ Uu < a ygB| 




OXOHIUM SALTS. 



atom closing tlie carboa chain, thus attributing to cHmpthylpyr 



/ 



CII-CCHj 

>< 



hydrochloride the stnicttiro CO /^^C\' '^*^* ^^^ "''"i 

these compotinds oxonxum salts, on nrcoiint of tlieir analog}* 
the ainiiiomum aa1t& 

These conipounJji can l>p jinnprl tn lie tnie miUk — elertnilylcs 
Xry various uicthuds. It must Ix- rempmlirnvl tluit aji aiiui-ous aolu-1 
tion of diim-thylpypi'iM- has a neutral reaction with litmus, and timt 
its electric conduct ivity \s vcr>' small. Thus, the oxonium base is 
only feebly basic ; its swUs— if they really deserve this tianie — imist, 
therefore, have the prnperties eharaeteristic of tliR salts of a weak 
baa*. Thejie pmprrtip^ fan be stiniBied up in the statpiiieiit that in 
arjueous solution such salts are hydrolyxed to a high degree, or, in 
other words, are to a large exten) ?plit up into free acid anil free base 
("Inorganic Chemictry ," 239). The aqueous solution of a dinicthyl- 
pyronium ealt actually has all the properties which would be anti- 
cipated for tlie solution of a highly hydrolyzed salt. In the first 
place, ita solution has a slixjuply acid reaetinn: the oxouiuin salt, 
however, is partly present aa such in the solution, as Waldex has 
demonstrated for the picrate of dimethylpyrono. He compared 
the qiiantily of pienc acid extracted from its aqueous solution by 
benzene with the quunlity extracted after addition of <time1hyt- 
p>'roR(> lo the aqucoua Rolutinn. The latter pmvetl to be less in 
amount; this must be explained by HRsuining the partial fonnatinu 
of a salt, whereby the quantity of fme picric arid in l.hn Milution is 
diminishrtl (84). 

Hytlndysis can alwi be detected by observing the deiitx-wion of 
the frcczin^-point. When thin is dcteriniiicd for stibilions of pure 
hydftwhloric acid of different concentrations, and subsequently after 
aildilion of dimethylpynHie to the aeid sniution, the depression of 
the fiin'/ing-jniinl in the latter ease is less iliaii the»um of the de- 
pret«io]i8 causeti by the hydrochloric acid and by the dimethyl- 
pyrone in their pure solutions; further, the difference between the 
Value thus calculate<l and the value observed i» the smaller the 
more the solutions are diluted, ae the following example shows. 
Tlio addition of .1 c.c. of normal hydrochloric acid to 10 c.c. of water 
caused a depressiiMi of 0X4Q''; lhi> addition of «'I262 gramme of 
dimethylp>'rone lo the mixlun* caiwwl a deprewcion of 0936*; the 






3if>6 



ORGAKIC CHEMiSTRY. 



ime qtiantity of dinioiKylpyroiie dissolved In 13 c.c. of watw 
jwered the freezing-point 0- 142'. Thp »\xm of the depressions was 

'thus 0-846* + 0-142* - O-OSS": the difftwnop between this and 
the obaent-d di-|.rfsaioii, 0-936', was tlirnr.fn- (tO,'i2*'. Tunica 
1 e.e. of hydroi:hJoric uticl and thr K&nii.- Cjuanttty (0* 1262 granunc) 
ofdiiiirtliylj>jTon<?wcrc Rddcd to 10 c.c. of water, thcdifferencewns 
only 0-03()', which is in eoii!i|>lete aprwrnont with the theon' o( 
hydnilyiic di!<8>iiciatiou. Tho latter increases with the dilutiwi; io 
fact, a very dilnte snhition of dimethylpjTone + hydrochloric acid 
must behave at* thniigb ihe two sutMlanccs were not in conibinntion 
at all. Partial combination takes place, however, when the solution 
18 more conccntratt-d, and this causes a depression of the freezing- 
poit)t BtnaUer than the ^iini (if the depressions obfier\'cd separately 
for each siilmtance. 

Among the other ways in whiph the salts nf dinielhylpynme 
can be pri>v»nl to Iichave like those of » weak base may be mWi- 
tiom^d the eluelric conductivity method. It was stated Utut a 
solution of the free base is a Vfiy bad conductor; when, Ihcic- 

.fore, the hydrochloride is dissoh'cd in such a large amount of 
water ft.s to be prsrtioally eomplet-ely hydrolyzed, the condueti\'ity 
of this sohitinn must lie equal to that of a solution of pure hydro- 
chloric acid nf the same molecular conn'ntralion. But if tlic solu- 
tion is not 80 dilute, an equilibrium is attained : 



IT -I- a' -I- C^A -^ [C\H,0,'H]' + a'. 

t>lRMiUi7l|»yMii* CMIon if dlmalhrl' 

pyraiie 



I 



In this case there is not as great, a number of free H-ions, whicli an* 
much more mobile than utlicr ratioiLs, and therefore conduct the 
currrnt much better. The wjnductivity of the solution must, therp- 
forr, be stnaller tliau that of hydrochloric acid of the same conci-n- 
tration, and must (lecrease as the equilibrium tends to the ripht- 

1 band ride, that is, RR the solution beeomes more concentrated. This 

fhas, in fact, been verified by px[)erinient. 

The power of forming nxonium salt.'s does not seem to l)c limited 
to dimethylpymne and analogous cnmiKiundB. ItAKVtiR and Vtt^ 
UGEB have shown that compounds rontnining oxygen, belong- 
ing to various claases of organic Ivxlies. such as alcohols, aldehydes, 
6st«rH, etc., are able to yield ci^'st&lline compounds with complex 



OXONIUM S^LTS. 



307 



ids, such as fcrrcwyauic acid; it is possible, ttiougb uat fully 
established, that tlicac ore oxouium salts. Tliey also atleoipted to 
obtain triinfthyloxonium iodide, CCHj),0 ■ I , anaIogi>u3 to the tetra- 
aJkylaiiimoniiirn salt-i, Init vcn-- unBiiccesBful. Timy an- <»f opiiiluu 
al Origxard'b cjtlicr coiiipniiiids of nJkyl magiiBKiiuu itiUidca ^82), 
ch as CUiMgl + (C,U,),0, must, be n>ganicd aa oxonium deriva- 




C,H, 



'>0< 



I 



Tlie pi)WGr of fontimg inie ealts by the addition of acids is eepe- 
ially devtdopc^l in tlie aJkyl-cumtioiincIs of the (■Imiiunts of the mtro- 
:ii group. Kxaiiipli-s of this arp also known wiili sulphur 
iiupoiuidH: au idkyi sulphide, such as (CjHjjjS, can uuil« with an 
yl iodide to form [C3Ht),[Sl, trialkylaolijhoniuiii iodide, from 
ri the free base can be obtained by the action, of moist silver 
oxide. It rt'iiiains to be investigated to what exteut eleriierit^ of 
other groups of the periodic systeui ar» capable of foruiing aualo 
goua compounds. 



CTAHOOEN DEKITATIVX8. 



Cyanogen, C,N^ 
i> V' 241, When mercuric cyanide, HgCCK),, is heated, it splits up 



/ in 



004^1 



into nicrcur>', and a ^as, cuanogcn. At the same lime a browu, 
amorphous polymer, paracj/anogcn, (CN')<. is formed, which is 
verted im heatiu^ Ui a high temperature into t-ymiogen. A belt 
niPthnd for tlic preparalHUi of tin? latter is tlu' interaction of wilu" 
tions of ]»oljis!uuin eyanidf ami copjier Kulphate; cuprir cyanide ia 
forniwl, uod u< oitct.- di;e«m[>o3(-sinlu cuprous cyanide and cyatiugun: 

4KCN + aCuSO, = aX^SO, + C\i,{CN), + (CN),.' 
Tliis reacUoD is aimUiiioiis to that between putiu«uuin iodide and a 
Bolution of copper sulphate, in which cuprous ioriide and free iodiire 
are formed, 

Cj-anogen is nearly relat^'d to oxalic aeid; when ammonium 
oxalate is heated with a dehydrating-agient, such as phosphorus 
pwitoxidc, cyanogen is prmhiced: inversely, when cyanogen is dis- 
solved ill hydroeliluric acid, il takes up four molecules of water, 
with formation of ammonium oxalate. These reactions prove 
cyanogen to be the nitrile of oxaltc aeid, bo that its conatitutioim^J 
formula in NsC— CsN. ^ 

Cyanogen is al»>o soine^^iuit antilogous to the halogens, as is 
indicated by the seeoml nictliod of preparation given above. The 
following facts also stipport this view : potassium bums in cyauoKcu 
in the »ame way as in elilorine, with fonnation of potassium cyanide, 
KCX; when cyjmoKcn is pa.'cwd into cauHlic [M)tash, [M>tasBium 
cyanide, KCN, an<l pittftssium cyanate, KC.NO, are pnKluowl, Uie 
pmeess being analogous to the formation of pi)tB«diun t-hlttride, 
KCl, and potassium hypctchlorite, KCIO, by the artinii of ehloriiK-- 
on eaiwtic potash (" Inorganic Chemistry." 56). Silver cyanide, 
like silver ehloride, is in congi8t<^nce a cheese-like sulMlaiiec, inaJi*- 
ble in wat^ and dilute acids, and soluble in ammonium hydr 



X, maiii»- j 
ydroxtdtagj 



HYDROCYANIC ACID. 



3«9 



At ordinary temperatures cyanogen is a k&s of pungent odour, 
its boiling-point being —20 ■ 7*". It is cxctaaivcly poisonous. It is 
stable at high temperatures, but its afjueous tfolution dccomjxweH 
slowly at ordinary tempprfttures, depositinu a brown, amorphous, 
ftiH'ciilfnt preeipitatp nf nzitlmimr an'ii. t'yanogen is inflwnmabie, 
burning with a peiicli-blrKQuini coloured flame. 

Hydrocyanic Acid. IICK. 

fi43. The salt*! of h;fdroc;f(inic acid C"prui«ic acid") are formed 
Tii'iK-n carbnn, nitrogen, and a .strong W-^e are in ronlact at a reil 
heat; fur esamplp, by ?tron?ly heating a mixture of carbon and 
piitttssiuni carhnnate in a stream of nitrogen. Cf/anidea are alao 
pr*wiuccii wlipn nitrogenous organie substancca arc heated with an 
,ell;ali or alkali-metal (4>. Ammonium cyanide rehiilts wiien am- 
Tnonis'fiaM is led ovlt rcd-liul carbon. 

WTien sparks from an indiici ion -coil are pas&ed tlirougb a inix- 
jtureof acelylene ami nilnigen, hydrocyanic acid is fornied. and, 
I «ince acetylene can be obtained by dJrt^ct synthesis (183). this reac- 
tion furnisliets a nurlliml of building up hydrocyanic acid from its 
ck'iiientp. It is usually prepared by heating potassium ferrocyanidc 
(843) wiih dilute .inlplinric aeict, nnhydmua hydrncyanie acid Iwiiif; 
obtaincK) by fractifiiuU diKtillatinn of the a<|iic^ouH distillate. It is a 
colourlciM Ii<iuitl with an twloiir msembling that of bitter almondu; 
, it lioiU at 26", ami in the snlid stale ineHs at - 14". 

When pun-, hydmcyanir arid ia stable, but its aqueous solution 
i decomposes with fonnation of brovcn, amorphous. in.soluble sub- 
[slanccs; the solution contain.' various conipminds, among them 
joaium fonnalo. 

Like most cyanogen dorivativea, hydrocyanic acid in an cxcesaivoly 
daDgeroin poi«oa. Tlie iolialatiou of hyilmgcn pcrniidd, or of air 
oontaiDin^tiblorine, itt employed aa an aniidotc. Its tozis effect de- 
pendt upon lh« dcgieo of Innlxntlon. na it dooa for the mercury ooio- 
poiinda<" Inorganic Cbcmiis(ry." ST4]. .-to that it miiHt be (lie cynno* 
gen iona llist exert Ibe poisonous .<i(.'tt'>ii. OMicr cvick-iicv leads to thtt I 
aame conclusion ; ttius, iKrtaiwiiRi ferrocTnnidc, vrhoacuqiieoua solution 
contains no cyanogen tonti, Is nan-pobononii. 

Hydrocyanic aci<l must be looked upon aa the nitrilr of forniic 
acid: H-COOH -» H-C\. Its fonnation by tlie distillation of 
iimmonium formate, and the reverse transformation— referred to 




3IO 



ORGANIC CHEMISTRY. 



above — of hyclrocyunic acid into ainntoiiiuin furaiatt: by the lakitig 
Ui> of two molecules of water favour iIiIm view, as docs al«> ihc 
formaUoii of liydnicyaiiic acid when chloroform, H -CCl,. ia wanned 
n-ith alcoholic niiiTnonia and ca«!<tic pot4ish (151). ilethylamine 
is obtained by reduction of hydrocyanic acid : 

nydrncyanic acid is one nf the weakpst acids, its aqueous solu- 
tion having hut. low electric conductivity, 

IlydrocyKKic acid Is preaemc in coiisidonible xmouDls in cenaln 
pUiiti; ii CAii b« otttiunMl from a vegelablo product, amt/gdalin, 
CmHkKOi I, wh[ch in a gluooaide 4811). Hud is fouutl in bitter itliiHiliilt 
and other substances. In coatjict with w&t«v, atnrf^Ialiti 15 deootB- 
poaed by an eiLzyiuo (898), emulain. alM pre.seiu in bitter almonds, 
into beoEAMchyde, b}'<lro>cTftni« aotd. and gluooso: 

C„H.:NO„ + 211,0 = (M1,0+ IK'M ■»- aC.H./),. 

AiiiyrJAlla Boiualdctijdi.- QlucoM 






CyauideB. 

S43. Thp (-yaiiidcs of lUi? aUcali-iiieiaU and of tliealkallnp-earth- 
metals, and ryaiiide of nuTCUry, are («)luhle; other eyacidre are 
itisolublr. All have a gn-at tendency to fonii complex salts, tiiuay 
of which, partimlarly those coiilaiiiiiiK alkiUi-nwdals, an- scthihlr iii 
water, and crystallijw wvll. The prrparation and properties of 
3i:)mc of these Rails are deseribcil in " Inorganic Chemistrj-, " SOB. 

Pota»gium vyanUk, KC'X (or KCy), in obtai'ied by heating 
potassium ferrnryanide, K,Fc(('iN), (or K,FrCy,>, to rednesa: 

K,l-e(CN)« - 4KCx\ + FeC; + N,. 

(Thfi sjinbol Cy ik sorHeliiiieB used to deunt« the radicle CN.) 

Potasjuitni cyanide is readily soluble in wat<>r, and with difficulty 
in strong; alci>hcd: it can be fused without undergoing dccumpof^it ion. 
ITic aqueous Holulitm is unstable; the [HitasHiuni o.vanidc takers up 
two niole('ule:< of » ater, slowly at ordinary- teiiiperat iires and quickly 
on boitinR. with elimination of aiuuionia. aiid production of potas- 
sium formate: 

KCN + 2H,0 = HCOOK + \H,. 

Pota-ssuim cyanide n.Iways has an odour of hydrocyanic acid, owing,] 
to the fact that it is dec^onipospfl by the earljon dioxide of the atmos- 
phere into this compound anil imtasHimn earlionate. 

The aqueous solution of potasauni cyanide has a atrooKly 



POTASSIUM FERKOCYMmDE AND CYANIC ACID. 



ill 



ine reaction, Ihe salt being partially hydrolyzed to hydro- 
aoic aciil anfi raiistic pfjliwli ("InoiiKanic Clipniistry," 239). 
Evidence of thia <l«M;oiiiprwiti«»n \» alsfi affonlrd by thi' possibility 
of saponiTyiiig cstcre with u solution of potassium cyanide, titiB fur- 
nishing at thi? same time a nioihod of iletormining the extent of 
the hydrolytic dcL-oinpoKitioti of tlii> salt. 

PoKis8iwm/(Trocyo»iM?c(" yellow pnisaialeof potash "),K,Fe(CN),. 
stallizea in Urge, sutphur-yt-llow crj'stjijs, ■nilh tUree molcculia oE 
atcr, wliicb can be driven off by the application of gentlu ht'ot, 
iving a white powder. It has been stated (242) tlial this sub- 
:Ancc is not poisoiKuis. f)n warniinj!; with dthtie Kiilphiiric ncid it 
it-Ido hydrnryanic add. When heal*-!! witli rormrUm/f rf sulphurip 
id, carbon monoxide is evolved; in presence of the sulphuric 
id. the hydnicyaiiic add first foniicd takes up two innlecnilcs of 
.■atcT, with prDthictioii uf uiiinmnia tind furmit! acid, the latter 
iuR i»imediat«ly docomiHvscd by the cunccntrate<l»ulphiiric add 
into carbon monoxide and wat-cr (88). This method is often uaed 
for the preparation of caHvin iiionnxide. 

Cyanic Acid, IK'NO. 

244. Cyanic <urid is obtained by heating iUs jiolymer, cyamtric 
acid (847). and paseiiis tjie n-suiiing vapoun* thnHie'i n fn-ciiing- 
tnixtiire. It is a coloiirlrBS h((Utd, atabL- below VP. If tlio flank 
containing it is removed from the freezing- niixtu re. so that the tem- 
perature rises above 0", vipomiiB ebullition bejrin.s, .sometimes 
econiponied by loud reports, and the liquid is ironverted into a 
hite, amorphous solid. This transformation was 6r!*l nl}ser\-ed 
y LiKBio and Wohi-kr, by whom the product was ealled "in-solu- 
ble cyaiiuriu acid ", or e-ifamelulf, which i.** a polymer of cyanic acjtl 
unknown molecular weight, (HCNO),. It ha«, however, been 
tly shown by StiNiiat that the transformation- product con- 
ins only about 30 ptsr cunt, of eyainelide, thy wmainder being 
cyanimcacid; these can be geparat#(l by treatment with water, id 
which cyanielide is only vcrv' spariiutly soluble, and much les.s so 
than cyanuric acid. Above 0^ an aqueoua solution of cyanic acid 
oluuiges rapidly into carbon dioxide and anuiiooia: 

ncNo + n,o = H,N + CO,. 

ooni^tulion of cyanic ai-Jd itself is unknown, but it yields 
of derivatives which may be n^^ordcd as being respectively 



I 

a 
ti 

C' 

V 

ble c^ 
^ f ur 
Hpecen 
groins 




s» 



ORC4NtC CHEMISTRY. 



derived froui normal cyame acid, C^^j . and from igtteyanic acid, 

<z 

Cyanogen cfJoHde. CNCl, may be looked upon ta the chloride of 
normal cyanic acid. It ia a very potsonow liquid, and b<iils at 
IS-S"; it can be oblaJned by the action of cliloriue on hydrocj'anic 
aoid,«nd[iolymeriz(wn'adily tocyojiunV chloride, CjXjCl,. Cyau(>- 
geD chloride Ls ntnivrrli^l liy the action of caiutlic potash into potatt- 
aiuin i-tiloridc and |K>taa»iiini cyanatc: ^ 

CNCl + 2KOH = CNOK + KCl + HjO. 

Egtera of cyanic acid have nnl been isoUitcil; they are probably 
fnrmed in the fintt instaiu-e by the action nf nndium alkoxides ujion 
cyanogen ehloride, since tlie polymer, cyanurif. rsier, (CNOC,HjJ„ 
can be readily separated from the reaction^prodtict (247). 

J^strfH of itocyanit acid, on the other hand, arc well known, and 
are obtained by the aoUon of an alkyl halide on silver cyauatc: 



OQ:N lAg + I 1C,H. - CO-NC,H» + Agl. 

The Isocyanic esters are volatile liquids, with a powerful, stifling 
od'our; tlie.v, too, piilynieme readily, yielding Mocj/anuriic catcr«. 
8Ucha8(c6\C,H,),(217). 

The constitution of ih*? ismtyanic eslers follows from their deconi- 
positirin inlu narban dioxide and an amine, by treatment with water, 
or better with dilutir alkalis : 

CO: N-CH, + H,0 = CO, + NH,-CH,. 

This reaction was first applied by Wurtk to the prcparati<Mi of 
primary amines, whereby they are obtained pure, and free from 
ficcondary and 1crtiar>' aminee. 

It bna liceu stniod (104) thnt primary amiiiM can be obtained from 
acid amidea by Uioactioti of brotniue and citustiv puLaab. Tliia is moro 
economically effected by diiililling a mixture of Iho ncid amide and 
blenohiR^- powder with limo-wntcr. The iDeebaiiism of tbe nwctioD 
lian boi'ii iiivi-^lie«<<'d lij' IIoouewbhft niid van Dobp. The fin! product 
lias beoti i8(i[ate«l; li jKiLAulwiitiitwl amide, with bruoiiiie in uuiori witb 
nitrnBon : li CO-KH, — R-W-NEIBr. The hydrogeu of the amido. 
group rnn be ropiiiomi bjr metals, owing to ilie inSti«nc« of lli« afild- 



THIOCY^NfC ACJD 



3*3 



nsidue. and ttiU ro|)Laeviiiviit Is couilderably faclllMloil \>y ihe intro- 
daciioD o[ 8 Br-atom. Tbo caustic putjish prtscnt cfkiiMsa thv (urmu- 
tton of A compound, R-CONKBr, whlcti is uiisUblo, biU onn be 
isolated. Tbie pot-fueium broivAiii idc rundllj' iinilergo«« Ati iolra- 
roolecixlar tr&UKrorniAtiun, similar Ui tli« Beckmann irftngfornialion 

ait): 

K— N— Br R— N— U 

I changes to 

0=6— R 



0=C-Br 



bromBinldr 



This traDBfortnatiuii-produot Io»ea EBr, with lorniatioii of an Uo* 

N R 
evftsic ester, || . whioh ia deootapOMd by lb« ««t«r pmoot Into it 

00 
primary amine and Od. 



Thiocyanlo Acid, HCNS. 

Z4&. Thiocyanic acid (BiUpfwci/anie and) resembles cyanic acid 
in ita propertipa, but is much niuw slalilp towards watf r. Il nan 
be obtained by treatment of barimn tliitwyaiiale with tlie calculjited 
proportion of dilutt- sulplmric acid. When the sulution is fraction- 
ated under diintmslicd pnissiire, and tlie vapimr passed over ralciuiii 
chiciridi- 1o free it from water, iiilo a vcs^'I cooled by a frctaiiix- 
mixturc, the anhydrovis acid in obtained in the form of a vorj' vola- 
tile. pimsent-smpUiitg Ii(|uid. which nhangcK quickly to a solid 
polymer after removal from the frepzing-inixtiin'. Whcji warmed 
with dilute sulphuric acid, thiocyanic acid takca up one molcriilc 
of "ivater, and decomposes similarly to cyanic acid (244), with 
production of carbon oxysulphide, COS, instead of CO,: 

HCNS + H,0 - H,N + COS. 

Jhtassiutn thiociiaruile i5ut>[Aiuvd by twiliii)CHHolutioao( potiusiiini 
oyanide vilti siilpliur, Amont; oibur upplicntioriK It U uusl iii Voi^ 
BAUD'S method vf silvcr-Litratioii. When silver uilrutc it added to ii 
■olation of potasEiam tbiooyiinate, sUtxr thi'jcj/artate, AgCNS, ia de- 
poeited in tbe forna of awhile, cheeee-like precipitate, iciAoIuble indiluto 
mlDoral aeidi. Fenic thiocyatmit, Fc(rX8)i, has n dnrk blood-red 
colour : its furniutioii is usi-d as n test for ferric anils. Tho red colour 
is due to [he D<iii-ioiiized niolDCulM Fp(CIfS)i, since neittjt^r the forric 
ion nor the thiocyanic ion are coloured in Bolutioo, and the colour 
is intensified if ioniiation is dimiuisbed, for example, br the addition 



314 ORGANIC CHEMISTRY. 

tit more or lli« r«rric uilt or of th« thlocfanate. Tbe red coloor is r^ 
moved \>y sbnkiDg op with cth«r, wIictoas loos cannot be extracted 
bjr this meHris. Mtrcury Clilocjtanat* lias tbe properly of s««ltiDg up 
when deflomfKwed b> lieat ('* Pliamoh'a serpeots ">. 

The constitution of ihiot-yame acid, like tliat of cyanic acid, is 

unknown. miJ it ruscmblcs the lattor in giviiig ristr to two wrics of 

a, o 
esters, tlie f/iiWj^nu; esters, C<\t' , and tbe iaolkioq/anic caters, 



• 



Thiocyanic eaters are obtained by the action of alkyl iodide* 
upon the salts of thiocy&nic acid: 

CX'S 1K"+1 |C,H, = CN-SCjH. + KI. 

They are liquids, insoluble in water, and characterized by a leelt- 
Kke odour. That the alkyl-group in these compounds is in union 
Tnth sulphur U proved by the nature of the products obtained both 
by n_'iiuct ion and oxidation. Rrdut'tioii yields niercaptami anil 
hydnjcyaniL- ai^id, uielhylamijiu Lwing obtained from the la(t<^r by 
further reduction: 

CN.S(V1, + 2H = CXH + HS-C^,. 

Alky l-sul phonic acids, such as CjHcSOjOri (68). are obtained by 
oxidation: 

Under the InBuencc of heat the thiocyanic eetcis are trans- 
formed into isothiocyanic esters; thus, diatillation of allyl thi«- 
cyanaie.CX-.-^^jHa, brinjts sbuut this cliaiige. 

The isotliiwyaiiic esters arc also called mutlard-oHs, after allj't 
isothiQcyanate, to which tlie odour and t^aste of niustard-siitls are 
duL'. Tlie following rfaelioiis prove that IhciC cotnpounds contain 
au alk>'l-group in uoioii with nilruKcn, luid have the coiustitution 

cCii ' ^^^ treated with concentrated sulphuric acid, they 

take up ir&tcr, yieldinf; a priiaar>' amiDC and carbon ox>'8uIpbide : 

RNiCS + II,0 - RNH, + COS. 

They are converted by reduction into a primary* amine and trithw' 
melkylau-, {CH^)j. the lotted probably resulting from the polymeri- 



FULMINIC AOD. 



3'5 



ifttioQ or the thiomethylene, CH,S. first fonned, wliicli is unknown 
in the free 8tat«: 

RN:CS + 4H - K-NH, + CH,S. 

AtMitioii- products of the miistaril-oils uill be described lat^r (254 
luid 255), 

Cjonimif/f, CN'NH,, ja (]htain<-<l in varinus reactions; for in- 
stance, by the action of ammonia upon cyanogen chloride; it is a 
crystalline, hygroscopic solid , and polymerizes readily. I ts hydrogen 
atomR can be replaL-pd by metals; for ('xample, silver yields eilver 
cifanamitlf, CN'-NAgj, which is yellow, and iiisohiblf in dilute 
aniinoniuiii hydroxide, wherein it difTers froni tlie majority of alver 
oompounds. 

Fnlminic Aoil 

M6'. Salts of j'ulminie acid aro obtained by tbo interftction of 
mercury or xilVRr, iittrlc acid, and alcohol, in certain proporlioru. 
Tlic h«3t known of thew is mervury fulminate, HgOiStO., which is 
pnt])arH(l uii ii lar^ ih.'1)1«, Hiitl emi)loyt'd for fltiiiig i>vvc:ti6'«ic>ii caps, 
and for other pnrpoec^. )t has boon monlioiicd (S31) that gunoolton 
cau lie expkxJec! l>y ihe detonatioa of n amall qiuintity oi this sub- 
•taace; and it [miduces Ihu ftami: rcauU iritli ol)ii-r e>i|)losi <'««., »» that 
I lie aoK-jtlled " fiiltulnatinK mercury" |ilay» an i![n|x>rt«nt part In their 
applitntion, 

tiilefr Aiin^iiiott, Ag(ONO), ia mucli more explosive than the mer- 
cnry salt, uuA bene* i» hm «iuplQye<l teehnioally. The exploeioti of 
th«si> «all8 bfl» a hriaaut, ihoiiKh only IiichI. effect ; ihia enabled 
HoiCARn, tbc diacovcrcr of moroiiry fulminar«, to i^xplodo a unial) 
quaiitily in abuUoou williotit injur}' to the latter, tire only effect hejng 
to shatter the leaden sliells cnntainmg the expIosiT^, 

Tree fulmiatc acid is a very unMabte. volatile Hiihatnnce ; it hait an 
odoiir resembling tbat of hydrocyanic aeid, and is L-xces^ively poi- 
aoiiuus. 

According to Net, the fotnnula of rulminic a«id is C=N-OU, cftn- 
taining a divalent carbon atom; when mercury fulminate is troaled 
Willi acetyl chloride, a compound of the forioulB CII)-CO(CNO) isob- 
taiued. Iniireaeneeof hydnwliloricncid llie fiilmiiiHte lakes up water, 
with formation of hydroxy littuiix! and fnmkic acid. It is converted by 
bromine tato a compound, Br,C(NiO*, nilti the coual iculfoDal formula 

Br— C=N-^0 






i 



Br-C=N-0 



316 



ORGANIC CHHMtSTRY. 



CyaDuric Acid and IiocjaAaric Aoid. 

247. Cyamirie Itromide, C,N,Br,. is obtained by hcatinp potas- 
gium fprricyanidp with hmminp at 220°. By hoatirK '■'^i^l' water, 
the bmmide is converted into cyanuric acid. (CNOH),, The lattor, 
however, is usually prepared by the action of heat on urea (252j. 
Two series of esters are derived from this acid, the normol and the 
uocijamiric fit/era, tlie former being called " O-tsters," anil tlw- latter 
"X-osterff." 

The normal cyaniirio estenj an> obtained by the action of Ro<liura 
alknxides on pyaniirir ehloride or bromide. The fomiaiinn of 
aleohol and ryanuric acid on saponification proves the Bikj'l-groijp 
in thpsic estrrs to Im- in imion with oxygen ; for this rconon constitu- 
tional funimlu I Ui asKJgnc-d to tlicni. 



N 



I. 



V 



n. 



RN. ,N.R 

do 



6R 



The isocyanurie esters result when silver cj'anurate is heated 
with an alkyl iixlide. Tlit-ir alkyl-group is linked tu nitrogen, since 
on boiling with alkali, th«'y yii'Id a priirian,' aiiiinp and (rarbim di- 
oxide, a deeomjJOMitinn accnuntpd for in conntituiional formula II. 
The 0-eRteni am formed when an alkyl iodide reacta with mlver 
cyainirate at onlinary trmprraturrs, but their conversion into the 
N-e«tcrs when heated explains tlio difference in the products ob- 
tained at ordinary and at elevated icmpcralures. 

Ki-Asos iiflfi wifyi^'stetl that cyamelide (S44) is t»ocyanurie aelil, 
and is ri'Iated to ilie isdcyaiiuric esters in the same way as cyanuric 
aeid is related to the normal cyanuric esters. The fomiatiou of 
i-yanurie ehloridtr by the aetion of phosphorus jwntODhlori'lr iin 
thi^ normal esters and normal cyanuric acid and the fnci that the 
tso-oHtera, and, as Senibh has recently shown, cyaniolide, do not 
yield cliluridGS under this treatment. 8Up|xvrt this view. 

Important evidence in favour of the ImintKfornLula for cyanuric 
acid has been furnished by Chattawav and Wadmore. who Iiave 
succeeded in repWinK the iiit-tal in potassium cyanurati* by 
clUorine. Tlitiy n-gard the compound formed aa (0:C: N -CI),. 




DERIVATIVES OF CAfiBONIC ACDK 



"248. Carbonic acid. H,CO, or CO(On),. is not knon-n in the Tree 
state, but i8 supposed to exist in the solution of carbon dioxide in 
wnter; it lieoomposcs vory reailily into its ai)}iydridE>, carlM)n i.!i- 
oxide, and WEt«r, It is dibasjc;, and is gi'iK-rally described, with its 
saXta, in inorganic tlwinistry ("Inorganic; Chtinistry," I84j. Some 
of its organic derivatives arc dcalb with in tluti section. 

Carboayl Chloride. COC'l,. 

849. Cwbonyl chloridf- (phoagtne) ia obtained by the sctioii of 
chlorine on L-urbon munoxldo. It was called phosgene by Sir 
HriiPHRY Davy, under the impression that it« formation by this 
means cnn only tnkc place in prrsonce of sunlight, a view sinoe 
proved to Ije incomrt. Ciirbonyl chloride is a pas with a powcrlul, 
stifling odniir; its solution in benzene, in whicli it is readily solu- 
ble, is a cotiunerLnal product. It Is employed in s>"iithi'«e8, both 
in tile laliorat-ory and In the arts. 

The rraetion.s of earljonyl chkiridp iiiditatn that It is the ehloridc 
of carhoniip acid. It is alowly decompo*e<l by water, yielding hydro- 
chloric acid and carbon dioxide. With alcohol at ordinary tem- 
peratures it first forms citlorocaritonic cater; 



a 









By more prolonged troatment witli alflobolt And also In* the action 
of sodium nlkoxidc, carttonie eater, CO(OCjHj)„ is product-'d. By 
the action of ammonia, the two CI-atoin3 in carbonyl chloride can 
be replaced by amid<j-Krou[js, with formation of the anii([e of car- 
bonic acid, urea, (XXNH,), (288). AU these reactions are charac- 
teristic of acid chloride.'^. 

Hie vlilorocftrbonic c«t«r«, alao c«ll«d Mion/ormfA esters, art ool- 
ourIe« liquids of strong odour, uud dislil without decompoMitlon. The; 



3»8 ORGANIC CHEMISTRY. 

arc cniplojrcd for the inlrodncllon of tli« group — OOOCilti Into 
oumpounds (UO). 

Ttio cnrboiifc cs(«ni Are nlso liquids, but are characterixed by the 
pottttcwtiori or nil (tllivroHl odour ; thoy ure insolable in «rtt«r, and ars 
Tsr; rradil; aapooiBed. 

Carbon Dtralphldt, CS,. 

250. Carbon diftdphide is manufaclured synthetically by passing 
tulphur-vapoiir over red- hot. carbon. The crude product has a very 
disaim'oablo odour, which can be removed by duttJlUn^ from fai, the 
pure product being an almost colourless* liighly refractive li<)uid of 
pthcrcal odour. It is InsolubFe iu water, boils at 46^, and \ita & 
specific gravity of l-2{i2 at 20". Carbon di-sulphidt; is poisonous^j 
and. as it is hij;Lly inllaniniablr, miist \>k handled with ea-at rare. 
It is an excellent st>lvent for fats and ()il3, and finds extensive appli- 
cation in the cstraction of those from seeds, It is also employed 
in the process of vulcanizinj? indiarnhber. 

Carbon disulphide is a stable compound, nml resists the action 
of heat, although it is an endotberrnic substance (*' Inorganic 
Chemistry," 119). It is, however, possible to make its va|>our 
cxpli»de by means of mercury ftiiniiiiate. The halocens have little 
action tin it at ordinan,- tempera turos, but in presence of a halogen- 
cnrrier chlorine and bromine can effect substitution, with pro<luc- 
tion of carbon tetraehloridc and tetrabromide respeclively. 

Carbon diinilphidc, like carbon dioxide, ia the anhydiidc of an 
acid, or an anhydrosulphide. With alkali-sulphides it yields tri- 
thiocarbonatea: 

TiaS + CS, = RaCSj. 

lUriimt 

(I'll blacarbaOB la 

Tliis barium salt is yellow, and diasolvcfi in cold water with difficulty. 
By the addition of dilute acids to its sails, frw triihioearbonit acid. 
H^Sj, CAn be i>blain('d in the form nf an oil which dt-composcs 
rradily. The pota.<tKinni salt is (nnployed in the destruction vf 
vine-lice. 

The potassium salt of xnnthic acid is foraicd by thcr&ction <if 
potassium cthoxide on carbon disulphide: 

CS. + KOC^H, - CS 



CARBO}} OXYSULPHIDE AND UREA. 



3>9 



Thi$ is effectecl by sliaking tip rarbon disulphirte witli a solution of 
caustic potash in absolutf alcohol, when potassium xantlia1* sepa- 
rates in the form of yellow, glittering needles. Free lantliic acid 
b verj* unaUble; it owes its name {^urcfros, yellow) to ita cuprous 
salt, which has a yellow colour, and resulte from the spoiitaiicous 
transforinaliou nf ihebruwnish-Uack cupric salt, precipitatwi frtmi 
a siilutioa of copper sulphate by th« addition of a xai]that«. 



Carton Oxysulphide. COS. 

261. Carbon oxysulphije is a coioiirlofiB, lodoiirloas, inflammable 
ga«. aiul it; ubiainrd by tht^ action of sulphuretted hydrogen od 
Uoryanic esters ; 

2C0-NC^. + W^ = COS + CO(NIIC,n»),. 

Mpniion haa b(^n made (246) of it£ formation from liothiocyanie 
esters. It. Is also produced when a mixture nf carhnn monoxide 
and sulphur- vapour \» pussied thmitgh a tube at a ntiHlerate heat. 

Carbon nxysiilplildocitu also tw obtaiiiMl Ijj-n romiirkublu roaoiioo ; 
when cnrboD-disalptiido rapour is piuswd over nid-bal kaolia (aluini- 
tiium wtit»t«l, wliioh pliiyH tlte pnrl uf au oii<lizing>agieDt, on« S-»tom 
of itic (TSt is replaoed by oxygen, and siliooa disulpbido, BiSi, siraul- 

Carbon oxj'siilphide is but slowly absorbed by alkalis. It yield* 
salts with tiictalhr alkoxide.s; the,se may l)e looked upon as derived 
from c&rbonatea by sinmltaneoiis exchange of oxygen for sulphur: 

COS + CjH^-OK = CO 

trt. co<^[J;. 

252. Urea owes Its name to itd occurrence in urine, as the final 
4Jeromp08ition-pnKluct of the albumins in the l>ody. 

An adult «xcret«s about. 1.500 gri-ftnimrA nf urin<>, contniniiig ap- 
proximamly 2 t)rr cent, of urea, in iwi-iity-four houra, &a that tb« 
daily produolioii of itiU aubAtin(>e< nmoimta to about 80 gr»mEuca. To 
obtain utva ft'nm urine, th« latter is flret coiKwntrMpd by evapora- 
tion. att«r whicb nitric aoid is atldad ; una nitrate, CO<MUi)i ' IIMOi, 



3SO 



ORGAHIC CHEMISTRY. 



^- 



(SMjisfireelpitnteil. and, on account nf impuTities, luumjoUon colour. 
Tbesc wlourtng-mattfln Kix- rcmovcO b> dissolving the precipitato in 
wataranil oxiilixing them with polasiiiuni pemmui^uate. The urea 
is Mt free from the Aolution of the nitrate by treaUneiit with b&riuni 
cnrbouiLtti: 

SCON.n.HKO. +B&CO. = SCON.H. + Ba(NO.). + H.0 -l-OOi. 

UTfla nllniUi 

On «vn[Kinitiuii to dryiiMS, a mixture of ure» and barium nitrate is 
obtAined from which tho or^nic cotnpoand can b« M)>anitcd by solu- 
tion in strong kIcoIioI. 

It has been stak-d <24&) that urra is to be looked on as Ihe amide 
of carbonic acid, ou account of ita formation from the chloride of 
this acidf carljonyl chloriite, OOCIj, thU reaction proving its cotistl- 
tution: 

jCl HlNH, /XH, 

+ = TO + 2Ha. 

XjCl H[NH, ^NH, 

OMrbonrl ohlorlda Upm 

A coDfirmatioQ of this view of tho oooRtitution of urea U its fomift- 
lion by ilio &c.{\nn of ammonin on rarbonio c«ter. 

Urea i« foraictl by mlililion of aiitmonia to iiwcyanic acid: 

^^ NNH, 

Ammonium isocyanate dissolved in wa1«r is transformed into urea 
on evaporation of Ilio solution. This is the method by which 
WoHLEB ufT<*ct*d his clasac synthesis of urea (1). 

ThiB reaolion, vrliioh has an important iMiring upon tho bistorf of 
orjciitno (^hi-iiilDlry. has Ihkih sludind in deiail bjr JAKiai WdUtEB and 
Hamiii.v. Thpir researolies have shown that the reveise traoiifonna- 
tion of iirra into unimoniuni ittwyaiintv occun also, ainoe. on ailditioo 
of silver nitrftC«, a solution of pnro nnm in lioillDg watar jrlelds a pre- 
cipitate of silver cyanato. An f.-quitibnum ia sttniaed : 

O0(NH,)f;::O0K HH4. 

Ur^ An-mi'iium 

THien thin ia rpactied, the solution only contains a rmy Hnall percan- 
tagA of iiLoeyanatG. It is almost ind«p«ident of tho tmnperaturs, 
proTiiig ilint lii« trniisfonnalion of the snlrms into one another It 
aocompaiiied by but slight cnloriOe effect (tOO). 



UREA. 



3»» 



The following is a proof tbut tti« formatioD of nrca i« occasioned hj 
tbP iiKvnuitioH of lfHt>ioiig and CON-iORS. Ttie reaciion would Iw 
DRimolcculor if it wcrv eauwd by molfrciilcs of anDmoniam iflooysoate, 
j<nd if it were, on tbe other hand, a reaction between ion*, ilii* Telocity 
equation for bimoleoular renctiona (101) wcmld n)i|>ly (" laorganlo* 
Chemistry," Bli. ax i* ac'ualty i)i« caar. It haa nlNn Ix'en ohaerrcd 
tbitt addition of both animoituiai Hiil|)lintc CKIl.<ii>ii4) m\A voinulum 
ttocyauatc >(CNO>iuiiH) aot'elerm ff!( xhn tniiiHlorinalion into nwn by an 
timouDt equal to that deduced from the liiore&se in concontracion of 
the iona. 

853. It was tnentioned (244) that, isocyanic esters are decom- 
posed by water, with formation of primary aimnos and carbon 
dioxide. If the primary aniine formed is brought into contact with 
a second molecule of isooynnic ester, addition tftlccs place, with pro- 
duction of a. tymmetricai dialkjfl'Urea : 



CO:NR + H,NR' 



/NHR 

CO 
Nkthr' 



This is a general method for preparing symmetrical dialkyl-uiras. 

A mottoalkj/l-urva is obtained by the notioH of ammouin, instoad of 
ao amtae, upou «u inoeyauic astur. 

yNRR 
Unafmrnftrieol dialkfil-urea*, du , nn prepared by tbe letlon 

of tfiocyanic acid on secondary aminos; tho method of procedure is 
analogous to that employed iii WuHLCit'ssyulhesiaof urira, andoonsiata 
in warming a aalution of ttie isocyanat« of a eocoadary amioo : 

CONIINHRB' = CO 

The uiisytuuK'trical dlnlkyl-ureaa are converted by treatment with 
abaoluto (lOOX) nitric acid into nitro-oooipounds. which wore dia- 
eoTered bj Fbanciiixonx and are cAllod nitramwa : 

Urea crj-stallizcs in elongated prisms, the eiyslal* resembling 
those of potassium nitrate; they are very aoliible m water, and 
melt at 132°. Like the amines, urea farms salbj by addition of one 
molecule of a monobasic acid: of these the ttUraie, CON,H.'KNO„ 



S" 



ORG/1 WC CHEMISTRY. 



and Ibc oxalate, 2C0NjH,C,H,0„ di»<xj|\« with difficulty in solu- 
tions of the currospoading acids. 

lu noma of its rcuitious. porlioularlj i& eertaiii ooadfinsatioD- 

pnMCUU, uro* bcluivM u thougli it li«l tli« itruotan C~OH. 

\Nir. 

An cllic^r of thii itourta Is obtained br udditinn r>f moth^l ulcohol to 

ojanniiildv, tlio rOkCLioti being faoililaled by tho preWQM of b;dro- 

ehlorio acM : 

^N yOCK, 

+H00n.= 0=NUi/ ■, 

CTanunUs ll«ttijllttuiirM 

This method of formAiioo indicntcs tlia coDstitution of the com- 
poand, whidi csii also be deduced in other waj's,BiicI» as llie production 
of inelliyl nlilonde on Iieating willi hydroohlorio &oid, which iadicAto 
thitt Ibe ClU-group Is not In uiitoo viiii nitrogen, since tinder this 

/SH. 
lraalin«iit niftfti/titTfa, CO , splits off methyUimine, ClffyHs. 

\snoH. 

Whfn heated, urea melta; it then Ix-gins to evoh-r; s gas. con- 
sisting priueipally of ammonia, but aho contaiiiinK carHon dioxide: 
after a lime the residue solidifies. The fnliowtig reactions tak« 
|)]ace. 

Two nioleculfs of nrpa lose one moIeciUo of ainmouia, with pro- 
duction of liiuret : 



CO 



H,N, 



XjNHrTf) UN 



\co 






?ai,.CO.XH-CO-NH, + NH,. 

BIUMI 



Tills is n crystnllino sutiBlaiiM' which melts At 1VA*, and give« a 
otiaractcristic red caloumtion when copper sglphato and cAuatic |w>taali 
nre addt-d to ita aqueous solution. 

On furtiier heatlnji, biuret unites with a molecule of unaltcrcHi 
urea» with ciiniioation of ammonia, and fomiatiou of cvanuric 
acid (847): 

NH 

!H1nh(X>.nr-oo.nh!h! w CO 



URE^. 



3*J 



I.ik* \\w acid amides, when liealed with bases urea decomjioseB, 
yielding carbon dinxide and ammonia. 

Thia qua*ilit.atit:* titimation (if urea in ttrine U *n «l>«Tatioti of 
ooDfliderable iraponaiiM in pb5^ioIOKical ctieniiilrj, and l« kITk-IoiI bj 
differeat methods. Bukbem's pToeOM drpendftupon tho dccooipoftition 
of urcA Into carbon (lioxidu and ammonia, oa healing vilbaoaiD- 
monlacal solntlca of baryU ; tho carbon dtoxido is ibos coDV«ne<] into 
barium carbonate, which can be csillected and weighed. In Kkofs 
method tbo n itifist^n is qtianiiiaiivelyBet free by treatment of fh*urr-A 
aniuti oti Willi orii: oj cauaUc poi^sli and broiai ne CO«rinan. Bromlauoft . 
i n yhicli poiawm im nyjioftMniltc ll pWAcnt ; ihg r|Uftiit:ty of arw caa 
be calcnlatcct irom the volume of nitrogen libcrnicd Liciim'siilrnllon- 
Toetbod is bflsed upon the forranlicn cf a vbii« prt>eipilate of the com- 
IKMiition200N,H«.HK(SO,).-»Hi[0, when mi^rrurlc utlralo»liilit»nia 
run Into a ditntA lAlution of urea (of about 3 per Mot. concentration). 
IThen •mccks of iliv mt-rciiry Halt baa bcpti iidik-tl. n drop of ili« 1i<|aid 
bran^lit into contnct with n solution of todiam carbonate );ivc6 a yellow 
prei'lpltate of baaii: oiltato of mercarj'. Urine contains anbstances 
L which interfi>re with these molliads of calimation ; an account of tb« 

I mode ijf pnwpdiini by which ihe corirct percenti^ of ur»a can be aa- 

I nttaiaed will bo found In icxi.bookii of physiological 01100118117, 



Polafiaium cjranale and hydrazine liydralc. IIiN'NH. + H,0, roaet 
^■^ touelher, viilh fonnation ot itmicaxbatide, NHi-CO-NHNlIi. a bano 
whioh melts at M*, and oombipea with aldehydea and ketoin-a tiniilmjy 
to liydroi y laminp : 

R..UjO^n,iN-NlI-C0.NU.-*R.-C:N-NH.00-ira,. 

The componnda thua formed arc cidled semifar(iatone.i : they some- 
tiuM oryBtalliM w*ll. and are employed in tlic identification and 
wparation of alilehydes and ketones. 

SeriTatiTCi of Carbamlo Aotd. 



254. Carhamic add, NH,'C(>"OH, which is the spmi-amid« of 
carbonic acid, i:* not kiiowu in the ftxv state, but only tut saHa, c»tcm, 
and chloride. The ammonium w/f U formed by the uoion of diy 
carbon dioxidv wi'h dr)' anmioiiia: 

/OH /OHNH, 

CO, + xu, - C^O ; + Nir, - c=o 



\ 



NH, 



Ammaiilum nrlumai* 



No ppctfipitrfte is formed wbnti carbon dioxide ia pansod iuto as 




JW 



OKCANIC CMEMISTttr. 



aahHiao of okiuni chloride, siiiee tbr multing aiMum 
', CO . is siJuIjIo in vatcr. 

tbe nits of wbsmic acid am hmted hi aolatioa, they 
uhe np water, fonnuiK raib<jnat». 
Ife men oi en r tam i c arid art calird urrfAano. They mrp 
bjr Ihr aetiaa of ammooia or amiskcs t^Wft the cetera of 
add or eUorourhooic acid . 



-y^ OOH. 



* H NH, /XH, 

= 00 +CAOH: 

/OTHtNH, /NH, 
00 -•00 

Uietlmei abo nmiit from Uw aebon of alcohol npoo isocyaourio 






+ HOCjH, - C^ 
NCH, \XHCH, 

a» abo obtained bj boiliiig add azides (IM) witb 



Sae* the aiidcs an cattly prvpaml fram the eMTwpoDdlogacida. and 
the BTcdMUMS nadilr jndid tbr rarrBspoadtng amnm. tbe carboxyl- 
gro^ eaa bf Um aMoa b* «a«l7 f ip to wd br the Kaida>groiip : 

R-COOa — B'OOOCili — B-COSHNH. -< tItx>Xi -^ 
aril ftMT Brdiarito 

-.R-5H00OCH, — R.5Hv 
tTrrthanri (fiadl wHhoitt deeompoeitian; ordinary urcthaQe, 



. m«hs at SI", and ts 7ier\- readily sotnble in vater. Wben 



•cs = 4Ca. 



IXRiyATiyES OF CARBAMIC ACID ANO THIOUREA. 325 

hoilccl with bases, it decumpoeea iato alcohol, carbon dioxide, snd 
aminoiiia. 

Correeponding saiphur dorivatirog cnti bo prepared \>y ftnnlogoiiB 
metlKxtit; rarboii dlsulphttte and alcoholic ummoDia yield (tmtfiurWnm 
Udhiocarbvnatt : 

•NH. 

C8, + aun, = 6> 

This salt is auatablo, aod on troatment iritb more ammoala readily 
Icses suIpbuKlUxl hydrogun, ioimiti^ mnmuiiium tkUx^tuxU : 

CS^M'" + 3NH, = C8:N.NH. + 8(NH.).. 



jiiumoiiluni 
dl UiltM» rbamala 



Ainiuouluai 
IlUocjaiiat* 



Primary amiueaalsoadd on t^, ioa maDQeranalcgoos to ammonia: 

/NUR 

C8, + aNH,K = US 

\8H NH.R 

]a prmenoe of roercnrlo or ferric chlorld«, tlkUKe substituted drthiocar- 
bainaiM ftl«> low »ulpIiur«Hed hjdrofpin readily, yi«lding muatard- 
• ofb (MB) : 

CB/ -« C3NR. 

\8H KH,R 

ThU reaetloD ig osed as a test fnr prini&ry aminM, Kinaa tiMw of tbo 
inustard>oils can be readily detected by thoir cbaracterintic odour. 



Thiourea, rS(NH,),. 

SU. AiDmonium isotJiiiKynvans yieiilx Mi'nurm in a maDneraaa]- 
ogoaa to tho formatiou o£ nrci frum amruuiiiuiu iinxiyaiiiLte (IU8). The 
I raosf carnation of the tliio-campoiind enn in ihJK lii«taii(!ft bi^i i-fTt'etad 
by beating it in tl>6 drj- slat«, but is no mor« otnplctc llian that of 
amnaoniuro cyanat«, aince ibiourea Is converttnl by b>Mt into ammo- 
nium iAOtl>ii>cyAtiAt«. Alkyl-d«rivatlVM of tbiourea rcaiiU from addi- 
tion of nmnionia or amiuw to the mtulard-oits. Die reaction being 
similar to th« formation of alicyl-substituted ureas from isocyitaio 
esters lloe. eU.). 

ThMc mode* of (ormatiou prove tbnt thocoiislilution of (biouroa 
is aipreued by tbe formiiln C^(NII|)>, baing similar 10 thai of urea. 
I)«rtvativa of thiourea Ar« abo koovn, bow<?v«r, wliicb indicaio tbo 



3*6 



ORGANIC CHEMISTRY. 



/NH, 

eiistence of a tantomenc form C— SH (SSS); thai, on addition of an 

alk>l iodide, compouiKlsare obtAiiie<l in accurdaucc willi (he equation 
J^^ / yNH \ 

cf-sia + i|C.n. = / cf sc.u. iiir. 

Tho ftlkyi -group in this compound is In noion with xtili^htir; Tor it 
(lucuiiipuacs niib forniiuloii of moraptaii, and oa oxidncioa yields * 
■ulphonio Mid. 

Thiourea forms welt-do(incd crystals, melting hi 173'. and readily 
solubktt ill water, bul with j;reat difflniilty in aloohol. On troacmenb 
with mercuric oxide, ii loses fii]l|)hurett«d hydrojcta, fonsiog cy^o- 
smide : 

/n|h; n 

CIS = of + H^ 

Gaanidine, CN,Ti,. 

256. (iuanidine is (onneJ l>y the itit^ractiim of aiumoaia and 
ort hot-arboiiic psUts or t-hloropicrici (161). This probably lakes 
place tliruugh atldition of fciur arnitio- groups to the carbon atom, 
the conapouiiil romied thcti losing one molecule of aiiiinouia ; 

/NH, 

OrthoMrbootr- mler NNH, 

This mothoH of preparinp gi]anidin(? provM it to liavR the oormtitu- 
tiniiiLl fi»niiula intlicati'ci, a view whirh (itidHKiipport In t\w Kynthesis 
of tliiscoiiipoutid fixHn animnnia and ryaiiariiidiM'fTpL'UHl by liealing 
tlie latter with au alcoholic: solution of ammonium cliloridc : 



#-^ 



<N 



NH, 



+ NH.Cl 



C=NH HCL 



Guanidine is pcnerally prnpiirpd by healing ammonium thiocyanate ■ 
at lSO°-lSo°. whrn it i^ obtained in the form of gunnidine thlocya- 
nal«, thf rcartion tukinf; place in stages: 

SCNHNH, -CS(NH,), -* H,N ON. 

AniinoDlu.111 Uii^cyAOftic Tblour** C/uumid* 



GUMNIDINE. 



327 



The cyanamidc unites with a molecule of the tinaltcrrd ammoiiiuni 
thiotyanat* : 

CT + NH.HCNS 



^N*H, 



= (c^nhMhcns. 

liiinaidliia thioc>'>n»M 



Guanidino i« a cnlourloM, cr>*8tallino substaiico, and readily 
absorbs moisture and carbon dioxido fniin the atmnsphon?. It is 
a strong base, unlike urea, which has a neutral reaction: the 
strengthening of the basic character, occasioned by exchange of 
carbonyl-nxygcn for an fmido-grnup, is worthy of notice, tluani- 
dine yielda many weU-tlefined, crystalline salts. 



NUroguanidine, C~JiH 



,c^ 



NH-NO, 
^ NH 



is obtBiiifd bv the action of fum- 



ing nitric &e\d upon guaniiliit?; when th<> Aolution in the iitrong 
acid is pourcKl into water, tlic slight solubility of the nitn>fruuni<Unc 
cauiscs it« p^■(^ipitatiun. On rcduclion, it yieldii aminimiuinidine, 

C=NH , which, on boiling wnth dilute acids or alkalis, decom- 

\nh, 

poees willi fonnation of carbon dioxide. ainitKiiila, and diamJtle or 
hydraeine. H.N'N'H, ('' Inorcaitic Chemistry ," 114). areaction which 
p rovea the constitution of nitrog:uanidinc and amino;:iianiiIine. 

An important derivative of guanidiue is arginine, CsH„N,0„ 
obtained from proteid compounds. It can be sj'ntliesized by the 
action of cyananiide on oruithine (200) : 



^ 



C00H-CII(N11,)-CCH,),-NH, + CN,H, 

OrnlUkliiH Crtsunithi 



" G00HCHNH,'(CH,)3NH 

NC:NH. 
NH, 

lit 18, however, not quite certain whether tJie cyanaroide adds itself 
\to the (u-NH,-group, as represeuted here, or to the o-NHj-group. 



imiC ACID QSOUP. 



tST. Vrie aeiH, C,H,N\0„ derives its name from its presence 
aaKuUl viuHim in urino; it is the oeotral puint of an important 
(nop *4 urea dcrivativps. It is closely relftt«d to the ureido^citlg 
ami thr arid-urtldfa (urtidei), wtiicb are ainiiu>acidB aud acid 
aoMiini, roDtainiog the iirea-rvsk'uc, XU,'CO'NH — , tostead of tb 

f V tlowtc oeid, CyB^fi^ nmy be cited as ooe of the acid- 
mtdns; it 13 obtained by the oxi^lation of uric acid. "WTiwi warmed 
W a king time nith allcalb. parabanic a«id tak«« up two moleoulee 
«f «mMr. fomiiti^ urpa and oxalic acid, a resctioii which proves U 
to be osalflurea : 

ySn OHH * 

ro\ OOOH ^ 



1 



00 



CX>OH 



H^ 



-NH OHH 

On CAralol tnatoMM with aDcalb, it takes up only one m 
r, jkUiacatotitricaairf; 




CO— NH-CO-\H, 

OOOH 



+ OHH 



Cfi^mfi^ is M impartHU 

MiB, frOMI VMCS 11 iaOMMMQ Djr 




itaoa wMiBilrieaefai; it 



be pnfmnA br other metbodL It is to be looked on as 

vilk a&afia. it takes np two 
( cawrtBT, wita pnoBCtiDft n VM aHd im iiiaiii acad : 

I 

+ ca 

I 

SH, 



CO Sn + OHH COOH 

00 CO —00 

00 — XH + oaa co oo 



URIC MOD CROUP. 



3=9 



CarboQ dioxide and parabanic acid are produced by the oxidation 
of alloxan with nitric acid. 

AlIaxAD is conveH«I by rmlaotion irtln nllnmntinf, tiiw n-nction 
be!ii|i: analogous to tlio rormation of pinitcoiio frou uOTt^aQ (1&0); 
alloxanitDfl has thererora tbe Btruotura 



^NHCO AM HOv CO-NH 
NHCO 



CO 
\ 



00. NH 



Alloxfti)tin« Is also (orincd direolly from uric *«ld by ev&poniting it to 
dryness with illlule tiliHc Add. When trc*I«d irith aniinflnia, it forma 
« purpIO'Tcd dy«, mu^f^ riii. the nmrnonium salt of purpuric acid; 
to this acid is assigiiml thv conslittition 

/•MI- 00 NIK CQ.NH 
CO ^C V ^00. 



\ 



NHCO 



00- NU 



This romutUon of murnide is omplojod as a ttst far urir acid 
AUoxantine U only soluble with consi<)i>rab'lo difficulty in cold waier, 
and KJvw a fine lilac colour wiilt liarvta-vrmcr . 

Allanloaie is a dfinoinpiiHitinii-ppnduPt of lirir ncid, a fact which 
has an important bearing on the constitution of this comimiind, 
from which it residts on oxidation with pntaiviiiini ix-rniangstiate. 
It has the atruotuie 



/NH-CH— XH-CO-X^ 



CO I 
NHCO 



All*ntalii« 

siocc it can be obtained a>'nthetlcall.v by hcBtiiig glyoxylio acid 
with urea: 

H 



/NHg__H0|-C—|0H_£^ UN CO-NH, 

CO + I nwa 

\NH !H H O|-CO 
Cra* OljDxjllc add 



/NH-CB^NH- CO-NH, 

-» CO I 
^NH-CO 



A]UBtobi« 



lacANBT, ^aemsTiFf 



- -i 

TSt^rtoc ■■rrn. lie- '"' *— ' '' "dev 



T3— : . 

I' „ 






•' =!r.-g: 
TS.—- 



?T- 



VMC ACID GROUP. 



33' 



vhieli, Ilka the anainm, julrls on one tD»lneiil« of IsoejuDlfl ack] 
when brought into contact with poUusium cynnate, rormiii; 
NH— CO 



io i«( N». 



NH— <:iO HlUS 
This BubetADM is pK"tit--uTk iieid, aud only differs from iirio acid 
ill containing tliu duiuenu of luioiher iiink-cule of wautr, wliidi, by 
hoihag will) n lurgo esci^sa of hydrochloric acid of 20 per c«Rt. 
stri;ii);Cli, can be split off in ttie maiiuor iiidicaCixl in Llm fwrcuulai this 
trcalmvnt yi«lds a subsunco wiib tlie cotutitntion assigaed to uric 
acU, and identical with this compoiind. 

Uric acid dissolves with great dilficulfcy in water, but is soluble 
in coiitt-ntrated eulphuric acid, from which solution it is procipitatett 
by addition of wat«r. It forms two series of salts, by exchange of 
ono or two h^i^tgon atotnii re.speciively for metals. Neutral 
sodium urate, CiHpl,<.JjNiiy+ HjO, is* mnrli more readily .loliibte in 
water than acid sodium urate, 2(^H,N,0,Xa + H^O. The neutral 
lithium mit is mfulcratcly noliihle in water. 

L'ric arid is prrscnt in urinp, and is the principal constJtnent of 
theexcrenicntof binU, rcpti]eH,an<lHer[)ent«; it. can tic conveniently 
prepared frotn scrpcnt-cxcrement. In certain patliologicikl di^iusos 
of the human organism, such as gout, uric acid i*i deposited in the 
joints to the form of sparingly soluble acid salts. Un account 
of the solubility of lithium urate, lilhia-water is prescribed as a 
remedy. 

868. A considerable number of compounds, containing the same 
carbon-nncleus as uric acid, occur in nature, partly in the animal, 
and partly in the vegetable, kingdom. To tlie ff>rmer Ijclong hy- 
jtoxanlhine, C^}i^S^O; xanthine, C^H,X^Oj; and grainijie, C^H^ti^O; 
to llie latter belong the vL-getable buKeu tlu^olirominf , CjH,N\0, : and 
cajfrint:, C\H,^\\()j. In order to assign a rational noincucUitun! to 
these suljotmiiM-a and other membere of the same group. Kmii. 
FtscHEB n^ganls them an diTivnlive.s of purine {p. 3S3), whose 
C-atoms an<i N-atonis are ntinibored us indicated in the formula 



nC' 'C.'NH 



333 



ORG^NtC OiEMfSTRY. 



\tiiilhiiK', th(.<«)bn>niine, and caffeine have the following Ktmctura] 
furinubB and mtimial u^ra: 

NH 00 



. y Nil— CX) V" 

"^ CO C— NHv 

tj 



I. !i ^: 



CO 



C-N(CH, 

J I' 
N(f.:ll,)-C N 

DliiietbrlnuitlilDe, (limtmiailiia, or 



-H; 



N(CH,)-CO 

CO C-X(CH)r. 

[ II Vh. 

N(CtI,)— C— 



Trlnufib]>lxiiii(liiiiv. c?K)Tt-iiie. 
or l:l:T.l(lRicllifl^:S- 

ThflobrcoDine and caSoIne n>«iitt from Llie iritj^CuiioD of nethyl- 
BTonpcv intn xniilhiiio. 

Xtuithtne, CiHtN.O,, is pre.ient tn mII Iho lii«iins of the tiunmii 
body. Il is a uuluurluBs jxxviJvr, nulubb Willi tliWculty in wnti-r, nod 
posvnasing a weak Ijahio olmractrr. <.)n oxidation, it yieliU atloutn 
nod urea. 

Thmibromine, C.ll.X.Oi, oxiatB in cocoa, ntid is prepared from tbU 
in>urr«. It. ia i>nlj- i:<,IiK)itly aoliibleiii wawr, and isconTerted l>y oxida- 
tion itilo ■mottotiirthy I iilloMin unci timttomflhjftmta. 

Onfftlnevtthrhu, ('•IlnNiOi, ia o. coiistLluent of coffee and tea. It 
erystalltsHH witti utie uiulcuuLo of vMer in long, silky iieedloe, and ia 
moderately tmlnble in water. It in generally prepared from toa-duac. 
On cnrofut oxidation it yields dUnethytaliojan and tnonomtihyhirta. 

Tbc pvsition of the mvUiyl-|rruui» in ihcobioiuiiie aud caffeine ia 
provoil by llio formation of thww oildatlon-proiiucU. 

Them ia an ovidi-nf rcBcniljIaiico belwopii the constilutioD of 
urir Bi!i(l aiiil ihiMu of xanthine, llieubroniine, and c«iTeme: 

NH-CO NH-CO 

00 C— J 



-NH 






Xnh/^ 



CO c— Nir 

i_- I 



iCH. 



NH-C— NH^ NH-C- — ^N< 

Vt\C acid ZanUiino 

lliefle formuIsB indieate the possibility nf obtaining xanthine by 
the retiuclion of uric at-id, and up to Ihc year 1897 numerous 
un»ucccssful attempts were made lo prcpure it by this method, • 




PURINE DBRiyMTiyES. 



333 



reaction ultinuitely effected by Emii- Fiscber in that year. He 
lias diseoverod several methods of eonvprting uric acid into the 
three cwmpoimds ineiuiuncd above, iiu-luding oue by wliich the 
manufacture of the tluTainMitically imporlant lawes, theobromine 
and eaffeViie, seems to be pusstble. 

To convert uric acid 'mXx* xanthine, it in first treated wilb pho*- 
phorus oxychloride, yielding S-<Kcy-2:G-dichloropvtTin<; this, ou 
further earefiil treatment with the same rcageut, is eonverted into 
2 :6 :S-trCchioropurine : 



C— NHv 

N— C N"^ 

•t: d^ KTrEchloniiiurtD* 



At 0^ and in presence of hydriodie acid and phosphonium iodide 
this trichluropurinv chajiges inludi-iadopwrine: 

C;HN,CIj + 4H1 = C^HjN.lj + 3HCI + 21. 

Rvdudioii of llitf iHjueuus siilutiun of di-iodoiiunno with zinc-dust 
ylctldK jmrtnt. a wblio or/KUilljne stibBtAnce, meliitig at ilt'-21T, 
aud rcrj- n-nd]!y eolublo in water. Il is a weak bi)«e, Binco It does 
HOI liim red litmuii blue. 



The Cl-atoui H iii trichlnropimnc is very stable towards alkalis, 
while the Cl-atomf< 2 and 6 are dioplaaed with comparative ease; 
when trichloropurinp iH tro&tmlwith siidiiim ethoxide, the Cl-atoms 
2 and 6 are exehangcd for etlioxyl-groupB. On lirating the eom- 
pnund thuH obtainwl with &jgi^0ion of hydriodic acid, the ethyl- 
gniupe are n-placi-d Uy hydnjRen, the Cl-atom 8 being simulta- 
neously exclmnK<^ for an H*atoni, with formfttion of xuntliine: 



N^=COC,H, 
CH,0-C C— NH 

li> 

a:«-Dle(li«Q ' <-iJ( 



I I 
-HOC C— NH 

II > 

tt—C—S 

XAUlhlii* <lkut«inerii; form) 



NH— CO 
-CJO 



C— NH 



XH 



-N 



JUnllilM 



334 ORGANIC CHEMISTRY. 

WTien2:&4icthoKy-8-<3Mon)ii}irine in heatwl wth hydrochbrio 
acid, only ihn ptiiyl-groiips arc replaced by hydrogen, nith produe- 
tioa of a compound of ihc formula 

HN— CO 



coc— : 



NH 




HN-0-; 



On methylaling this siibfitanc&, its three H-atoms are exchanged 
for nKthyI-g^o^lp«, yielding ehlorocajfe'in^, n-hioh can be cnnvcrlwl 
by nascent hydnigvn into calTeTtic. TtiiH is, tliercfore, a niethiKl i>f 
pn>panng GBfTc'iiie from iirlc acid. 

]£wL FiscHEK has disrovcrwl a very characteristic and Mmple 
lucxlc of effecting this methyl at ion — agitating an alkaline. a(]iirou$ 
Bolution of uric aci<I with methyl iodide, whereby the four hydm- 
gon atoms arc readily replaced by methyl-groups, with formation 
of a tctpamothyluric acid. On treating this with phosphonis oxy- 
chloride, POCl,. chlorocaffGYno ie formed in accordance with Ihe 
equation 

3C,N.0,(CM.), + POtn, = 30,Np,(CTIO/1 + PO(OCH,)„ 

and cao be converted by nascent hydrogen into caffeine. 

Electro-redaDtioa of Parine Deriraf ivei. 

Tapel has stated thai eaifeme, xanthine, uric acid, and other 
ninilar comjMmniU, nnlueiblc with difTieitlty by the nrdinan* nioth- 
mls, readily add on hydrogen evolved by plnrtroJ^'sis. I'"or this 
puqKise the comiMiumls are dJj«o!vei! intiiilphurieaeid, the8lren(»th 
n( whieh is varied l^i suit Ifie pnrtieular eompmind, anil lies iK-twi-OD 
50 and 75 per cent. This solution i:i contained in a porwif> cell, and 
a lead cathode immersed in it. This cell is placed in stiJ])hiiric aeid 
of 20 to 60 (jcr cent, slreuf^th, which cunlains the anode, 'llie 
hydntgen evolved at the cathode hy tlie current readily effects the 
n^hirtioii of the above-mentionctl cwmpounds. 

Xanthine ami Ms lioinologuies take up four atoms of hydr 
booomiug transformed into deoxtfdmtxitivts: 

CbH„0,N. + 4H = CJI„ON. + fl,0. 




ntscrno-REDucnoN of purine oERiyATiyES. ns 

TTicsc uru stronger bases llioii tlic-origiiial substances, which have 
very weakly baac propcrtica. 

Thp r(>(hiction of nrir nr.ic! is somewhat renitirkable, requiriug 
ax hydrogen atoms, and yielding purono: 

C,H,(>,N. + SH = CjH.OjX. + H.O. 

It is the carlwn atom fj whose oxygen atom is replaced by hydrogon ; 
At the same limo, two hydrogen atoms an* ad{l[>d at the double Unk- 
ing ni the urio flckl moleniile: 

'NH— «C0 NH— CH, 

KO »C>-'NH\„^ CO CH— NH^ 

/"CO— >co. 

VrlcMicl niniiie 

This structure Is pnivfld l>y the fact that punnie yinlils two mole- 
eiiles of COj on hpalinp; with baryta-water, kh that it must rtmtain 
two nnaltervil iirpa-residiipj*. which nccpNiutatcit thp prpspnrr of the 
carbtmyl-Krciups 3 and S. Thr carlionyl-grnui) 6 can be proved to 
be the one n'duc^ed in xanthine and its homnlofoics- 

Ptironi^ \ii neither a ba^ie ntir an acid, and is nnt attacked by 
oxidizinp-agcntj;. When wanned with a 10 per cent, solution of 
caiutie soUa, it m Iraiu^onneU mtu iio^irmu:, whieh has acidie prop- 
ertiea, and \% readily oxidized. 

Tlie app]icaii(m of ihf electro-i-eduction mi-thod was at first 
attoDiIed by many diflicultics, groaiiy varying yields bcuig obtained, 
even when tht^ process wojt appatviitly earned out in exactly the 
some way. T.vftl hxis both dtsi-overed the cause of this anomaly, 
and indieaU^d a method by which tht< prriceBH can be kept under 
coiitml. His investigations are of general interest, and are worth 
cle«cribiiig m some detail. 

In onk-r to have a method of obwrving the course of the reduc- 
tion jjrucCHS, Tafel closed the porous cell with a fitopjier, through 
which the cathode and a dehvcrj- tube for the g;as were introduce*!, 
cart- beinK taken to make the connections air-tif^ht. A second 
apparatus, exactly similar lo that used for the reduction, but con- 
taining aeid alone, without the purine derivative, was introduced 
into tlie same circuit. Periodieally, tlie gas from both was collected 
at the same time during a apace of one minute. The difference be- 



336 



ORGANIC CHEMISTRY. 



tween these quantities ar gu is a <Iirt»:t mE'&sure of the coursn of 
tJie reduction durini; thai iiiinuic, since it iiidicalos the qumitiiy uf 
hydrogrn uwcl fi)r llic ndtictioii. 

When this quantity is rcpreaeuted ffrapliieally, the abscissiD 
standinf; for the time which has elapsed since the bepinnJnp of t Ik 
experiment, and the ordinales for the ciiiantity of hydrogen iise<i 
for the rwhiclittn, tlie normal course uf ihe latt«?r must Iw indicated 
by Fig, 70, since the quantity cf hydroRca absorbed in the unit of 
tJme mu»t diminiKh in the same proportion as the quantity of unre- 
duced purine derivative. 

Tapel has, however, observed that the addition of traces of a 
platinum or eopper salt, as well as tif rertatn iilher sails, vory 
quickly redure-s the quantity of hyJrogeji al»sorbe?d to nparly zero, 
the grapliic n^prescntatioii in this case for the additi(in (if ' 04 niilli- 




TtHE m VIHVTE* 



Fio. 70.— Normal Rkdoctiok 

CUKVK. 



Fio. 71— Ahnosmal Rbddctioh 

CURTK. 

grammes of platinum for each 100 square centimetres of cathode- 
surface is shown in Fig. 71. This indicates that the slightest con- 
tamination of ihe load of tho eathotJe by certain othei melals is 
sufficient to almost wholly stop the plectro-reduction. 

The followin^t considerations afford an insight into the cause of 
this phrnoinennn. Hydrogen is only evolved hv the passage of an 
electric current through dilute sulphuric acid when the difference 
of potential of the electrodes exceeds a certain value. This is a 
tnininium when plalimini eiectrodes are used, and very nearlv 
coinciiles with the potcnlial difference to be cxiR'cted on thwireticat 
grounds for a reversible hydro)i;en-sulphurie-aeid-o.xvgpn-element. 

"WHien the cathode is nia<le of other metals. Lbc clifiference of 
potential is crcaicr before the evolution of hydrogen ; for this a 
tupertengitm (German. Crfrmipnnnwng) is necessary. This has a very- 
large value for lead, but as soon ns the least trace of platinum or 



b 



ELECTRO-REDUCTION OF PURINE DERjyATiyES. 337 

of certain other metals is brought into contact with the surface of the 
lead cathode, the supertension disappears, and with it the power 
possessed by the evolving hydrogen of reducing purine derivatives. 

This has a deeper lying cause. The diCference of potential 
regulates the energy with which the discharged ions can react, for 
the pressure under which a discharged ion leaves the solution 
depends only upon the difference of potential. Nehnst states that 
by varying the difference of potential it is possible to obtain pres- 
sures from the smallest fraction of an atmosphere up to many 
millions of atmospheres. Heiice, reductions which are unattain- 
ble by other methods and without supertension are possible at 
cathodes where it exists. 



SECOND PART. 

AROMATIC C()Ml*orXDS, XSD SUBSTANCES 
RELATED TO THEM. 



IHTBODOCXION. 



269. With but fow pxwptinns, the ccinipt>un(Js described in the: 
first part of this lunik eoritaiii an open rhaiti. As examples of these 
exceptions, closTd-chain i;»iiipi)un(l!tstirh as the lactones, the anhy- 
dritles nf ch'liasic iirids, and Wiv. urit; at-id groiip may bo nicntioncd. 
The cioiM-d chain «f tltrsc ('oinpoiiiids is very ri-adiiy otx-ned, and the 
dose relationship of (heir methods of forniation and proporlies 
with tliosc of the open-ehain drrivativps, makes it dosirable that 
they should be inchide«l in n deseriplion nf the fatty compounds. 

There exists, liowever, a large number of substances coniaiiiing 
dosed chains of great stability towards every kind of chciiiiral 
reagent, and whoae properties differ in ntany iinpurtjiiit n-^iH-ets 
from those of the fatty compounde. Chief among these is benzene, 
CftH,, with its derivatives. The molecule of heniene rnntain? & 
clnsnd chain of six eartxm aloinit (263) ; tliiH siilislniiee »n<l Us deriV' 
atives comilitiite the gniup of aromatic compounds. Renzcne can 
take lip six hydrogen atoiris. with formation of hejrameth/lrttr, r«ll,j, 
a rompoitnd whirh also contains a closed riLrboii ehaJn of six atoms, 
but approximat c» in pruperlics lo the fatty much mure thaittn the 
aroraaiic group. Compounds of the formula C„Hm are also known, 
containing a closed chain of four or five carbon atoms, and they, too 
liave similar properties to tho fatty eompounds. 

The closed chain, ring, or nuclfus^ in benzene and its deriva- 
tives, and in the closed-chain hydrocarbons C„Uj„, consists of the 
atoms of a mngle element, carbon. Compounds of this kind are 
called komocycHc. 



THE AROMATIC COMPOUNDS. 339 

Closed chains containing atoms of two or more elements are 
also known : pyridine, CbH,N, and its derivatives, have a ring con- 
taining five C-atoms and one N-atom; furfuran, C4H4O, four 
C-atoms and one O-atom ; pyrrole, C,HjN, four C-atoms and one 
N-atom; Ihiopken, C,H4S, four C-atoms and one S-atom; pyrazole, 
CjH^Nj, three C-atoms and two N-atoms; and numerous other 
examples might be cited. Such substances arc classed together as 
hetiTocydic compounds. 

There exists another class of compounds containing condensed 
rings, or two closed chains with atoms common to each. A type 
of those is naphthalene, C|,Hg, containing two benzene-nuciei. Two 
dissimilar rings can also have atoms in common, as in guinohne, 
CjHyN, which contains a benzene-nucleus and a pyridine-nudeus. 

Since numerous derivatives of all these compounds are known, 
the scope of this — the aromatic — division of organic chemistry is 
much more extended than that of the fatty series The descrip- 
tion of the aromatic group is, however, greatly simplified by the 
fact that in it the properties of alcohols, aldehydes, acids, etc., 
already described for the fatty compounds, are again met with. 

The most important of the closed-chain compounds are benzene 
and its derivatives, and these will be described after a brief con- 
sideration of the compounds of the formula CdH„, containing rings 
of three, four, or five carbon atoms. 



POLYMBTHTLENE DEEIVATIVE8. 



I. TBIMETHYLEBE OEEIVATITES. 

CB.V. 
SOO. Trtrntlhylcitu, CiU* = I >CIli. is obtiUiied t^ the action 

CII.'^ 

of Boditim on trimetliykiie bromide, CH,Br-CII,-CH,Br (IM). It 
b a Kaa, wbich liquefies at a I^^eHfl(l^e of from fisa Xo kIx niRi(M(ili«r«. 
and iii not identical with propylene, CHt:CII-Clli, aiiu'v witli liroinino 
it forms an luKliLJuti-iinHluct only very »lon1y under IIjo iuHneuce of 
snnlight, yielding liinifttijlono bromido. This r^nclion, togotbor vrith 
its aynthesia, proves it lo hare the wbovc conatiimlon. 

DerjvatiTes of trini«tliy]etie aro obtained by the action of cihylecM 
tironiide on aodiaoiBlonlccscsr: 



CM, 



Br- 
Br 



+ Nft. 



C(OOO0iH,), = I XCCOOCHO. + SNaBr. 



By Kaponifloation of this eater a dibanic acid is obtainw] vhlch uplits 
off CO, when heated, with formAtion of tnmethi/laiscarbarj/lic acid : 

I^CU-COOH. 
CHi 

n. TETRAKBTHTLEIIE DEBITATIVEg. 

961. TctrnmcthylBii^ iiself Is iiol kuuwu. but it« deriratlvca iiro 
obtaicLud iLtiiilugously in )rinii>lhylvnw compouailii. Wlieii sodiomn- 
Ionic ester reacln with trimfithylono bromidv, the 6»t«r of A ti^ra- 
tntt/tfflenmiicarboj:y[ic acid is (ormm! r 



CH, 

on. 

OH, 



Hr 



+ N*, 



Br 



CH. 



qCOOe.H.), = VHt C!(CO0C,H.). + 



9NaBr. 



CI!, 



m. PEHTAMETHTLENE DZRIV&TITES. 
28S. PontatUKthyloQfl il^rivudvcs can Ito obtalnwl by a similar 
motbod, the Action of tftmmotbyloiiQbrumido oii sodiumalonic ester. 



POt.YMF.THYLENE DERIb'ATtyES. 



341 



When ihocjilciiini salt «t adipio aci<I is aiibmiltcd to drydisUlIa- 
tioD, a keto>dei'ivxlive at pentamelhylvuiji is formed : 



CH,.CH,.CO.|0\ 



OH.-Cll,. [CO O 
C&lclum ofUpAio 



>Cji =: CaCX). + 



y 



oHiCHis^ 



CO. 



OH. -OH/ 

KetU'|ient«> 
nwthfk'ne 

Tlie Structure of this eoinpound U prov«d bj- iU oxiditlion to glaUltio 

acid : 

CH,CH,v CH.OH.OOOH 



CH.CH, 



/ 



CO 



CH,-( 



-COOH 
IJIuInrfD aoIJ 

Pmtauutftjflttit is obtained by (b« rodiiDtion of ibia ktto-derirative, 
tliv carbon )'l* group taking up two Il-atomii, wilb fnrtnnllanof a C'HOH- 
group. By trv>Hliiieiit with hjdriodic ncitl, bydivzfl is fint rvplac«d 
bj iodiae, and llti»lly hy IiyiIro);iMi : 

Cn,.CH^ (.'H,CH,> 



I 
CH..CH, 



/ 



CO 



I '^CHOH 

cn.-CH,^ 



— I 



CM, CH, 



CU.CU, 



CHI — I 



CH.CU.x 



CU, CU.' 



PentaiB«th7tea« is » coltmrlns Ii<]tiid boiling At 50°. 

Afcording t.o the "tonsion thcorj* " of Baever (129), the fonna- 
lion of a I rimethyleiie-ring and a totraincttiylpui'-ring necessitated 
an altiTation in the dirortion of the affinitieg, since only in a 
chain «»f five earbmi a|nm.<4 arr the »niiiili<'.s sufficiently near to 
one anothpr to fomi a ring without Mng hcnt from their direetion 
(169). It followa frntii ti)i» that the pent«tnethyleiie>ritig must be 
v«r>' stable, while the tctrainethylcue-rin^. and still more the tri- 
roothyleiK'-riiijK, liave a t^iiilency to njjen, so as to bring back the 
boiHls to their original dir(.>etioii. These conclusions arc fully s%x\t- 
|Mirtei] by I'xpcritncnl. Triniethylene forms an addition-produet 
with brouiini- (:260).and willi other substaneea, such as liydrioJic 
aci(], whereby the closed chain is opened. The reaction does not 
take place so readily as the addition of brnmine to substances con- 
tailUOg a double bond, mich as propylene, because the iMmda of such 
onnipounds are more alteiwl in direction, and are thi^rehirv niore 
easily broken, than tbos<* n( the clawd rhain of triniethylt-ne. Penta- 
methyleno does not yirld an .iddititui-prodiict with bniniinc, and 
(Uspla>'s the same stalnlity towards nilrio acid and sulplmrit; arid 
a» a saluralL-d hydrocarbon; it thus shows no tendency to opening 
of the ring. 



342 ORGANIC CHEMISTRY. 

A consideration of the great resemblance between the proper- 
ties of pentamethylene and of the saturated open-chain hydro- 
carbons leads to the important conclusion that the formation of a 
ring does not in itself make any aitcraiion in the properties of com- 
pounds (378). 

Analogous to the production of ketopentamethylene by the dry 
distillation of calcium adipate (p. 3411 is that of ketopolymethylene 
derivatives from the calcium salts of the higher saturated dibasic 
fatty acids; thus, calcium pimelate, CyHioOiCa, yields ketohexametkyl- 
ene, and calcium suberate, CgH^O^Ca, yields ketoheptametkylene 
or siAerone. The yield of the diflferent homologues obtained com- 
pletely agrees with Baeyer's theory; for the closed-«hain com- 
pound with five C-atoms it is theoretical, and diminishes rapidly 
for its higher homologues with increase in the nimiber of Oatoms, 
a proof of the instability of the rings containing six, seven, or more 
carbon atoms, of which further evidence is afforded by-the conver- 
sion of hexamethylene compounds and aromatic derivatives into 
pentamethylene compounds by hydriodic acid at a high temper- 
ature. 

Hexamethylene lierii'ativea are described later (270), 




t" 




S63. Certain siibstfliipf>3 fnund in the vegetable kingdom lire 
charact*irizcrl by thi* pdsstwsion of an a^iwablo aroma; siiph are 
oil oj biUtr almon^x, oil oj rarmwati, nil of cumin, Utlsam n/ Tolu., 
gum-benzoin, inniV/n, etc. These vp-gctabloprodiK^ta consist prin- 
ciiwlly of siibstannM of sonicwiiat similar nharnctor, which differ 
from the fatty compounds iti ocintoiiimg much less hydrogen in 
prop<Jrti<tn to thff other ek'nient^i: thus, cj/mene, C,oH„. is obtained 
fminnl) of t-arraway ; lolfifTip,Cj.]lt, from bal^tam of Tolu ; and Aenzote 
acifi, Cjll,0,, from gum-benxoin. The saturated faity coinpounda 
with the same number of C-atoma have the formulie C,aHj„ C;H,^ 
and C,H„0„ rpBpectively. 

Before the nature of the so-called aronuitit: compounds had been 
closely investigated, atid on atcouiit of their ext<»mal similarity, it 
v!Bn cuHtomary to reganl llit'iii as niemlwrs of a fcingle group, jnst 
as ordinary butter and "buUvr of aiiliiiiuny." SbCI^ were elasied 
togcthrr txTftuac of tiicir similarity in eonsislency. This method 
of clufttificiition is still adopted fur eoni|»iund» with analoeovis 
proptTl ic», but of imperfectly understood conislitution, such as the 
bitter principles, vegetable alkaloids, and many vegetable dyes. 

A closer study of the aminalip eonijwtunds ha« Khonni tlmt the 
old and somewhat arbitrary cliiR^ification acrording to exlcmal 
resemblance is well foundeil, sinre all these siibstanr^s may be 
looked upon as derivatives of one hydroearbon, hcmcne., 0,11,. just 
asthefatty compfjuiuisari- to be rrgardi-d a« <ierived fmm nirthane, 
CHi. Thus, on oxidation, toluene yields bcnsoi'c acid, whose cal- 
cium 8alt is converted into benzene by distillation with lime. Tho 
cUbasie terephtlifilic acid, C,11,0«, Is formed by the oxidation of 
cymene. and can be similarly transformed into benzene. 

Tbe discoi-ery of this relation by Kekui.!; brought into promi- 
nence the question of the constitution of benaene, the basis of all the 
aromatic compounds. When its fonnula, C«H«, ia compared with 

343 




344 



ORGANIC CHBMlSTfiY. 



that of the sBttirated parafHn contBiniiig six CVatoniB, hexane, 
C,H,„ it is swn that it contains a much siiislter pcreeiita^ of hydro* 
gen, Bitice thcif are eight I I-atonie fewer in its molecule. It might 
be enggcstecl that benzene, like other hytbwjirboiis pf>or in hydrc^eo, 
8uch asCoH,, aiidC,H,o,c^»ntain8 multiple carWn boiiUs.but the i>rui>- 
ertire of bt^nzetie di» nut admit u! Ihis asKUinptinn. Com[i«unds c<m- 
tttuung a miUliplo earboii bond readily ftinn ad<Ution-pnHluct» with 
thi- hiiloKi-ns, ar^ vitv sensitive U> oxidizing-agents, and easily n-acl 
ttitli Baktbr's rfagcnt. (123): U^hw-iil- lacks tlicse proptTlics. It 
yi<'lda lialoRen mldition-producta very slowly, whureas coniimumls 
with a niu]li|)Ie carbon bond fonii Ihem instantaneously. It musl. 
therefore, be eunclniied that l)on/ene does not contain multiple 
carlxin bonds, and that the carbon atonw in its molecule are Hnkeil 
together in a sprriiil manner. 

Other ron^derutiimii lead to the name t^onclusioD. BACrcii has 

rdiscovcrcd ccrttun dibasic acids, derivable from hcxamcthyleQe 

(tyclohexanc), 

CH,— CH, 

H,C OH,, 

CH,-ai, 



by exchange of hydrogen for carboxyl. Removal of two or four 
hydrogen atorca from th3se hexaniethylene derivatives jiclds com- 
pounds whoflp behaviour shows that they contain a uiultiple earlmn 
bonil. It would be expectwi that the abstraKtioii of six hydrog<Mi 
atonia would prmluee a com|X)unt! of an even inore luuaturaled 
character, but a bc-nzene derivative lacking all the properties ron- 
fen'ed by a double buiitl ia forrit-d instead. The elinuaatiot) of 
(lie third pair of hydrogen atoms from the hexamethyletic doriva- 
tive, unlike that of the first and tievond pair, ocea^citis a sudden and 
complete change in prt)pert ie.t. 

In imler to understaini the manner of Unking of the betizene car- 
bon atf>nm, it i& first iicetrssory to know tlie relative distribution of 
^ts hydnigen and carbon at<ima. Two facta sufhce to dctennine 
this. First, no isomrre of the monosuhBtititHon-prvduda oj 
extst, Seeniid, Ihr disutistttution~prodw^fi exist in three iwmeric 
jomia. Hence, there is ouly one uiouubrotnobenzcne, Cali^Br; but 




COMTiTUTlON OF BENZENE. 345 

thPM dibromobenienes are known, and are distinguished by the 
prefixes ortho, mcla, am! ptira. 

h fnilows from the first of lhe«e facts that the six hydrogen atoms 
aj bcnztmc are o} equal valur; that is, replacement of any one of them 
yields the same monttsiibstitution-prmlurt. Three fonnulfie. in 
wliich the six hydrogen atoms arc of equal value, are posable for 
benzene: 

I. C,(CH,),. II. C,(CH,),. m. (CH),. 

■ It has now to be considered which of these formulte agrees with the 
second f&ct statt^d above. 

A disubatitution-product of a compound with, formula 1 can be 
either 



(■ \^^^ or C (*^«^ 



No other isomers are possible, so that this formula is inadmissible 
as leading to two, instead of to three, isomers. 
With formula 11 (our iRomers itccm p(t»»ible: 

a. fCHX 6. (CHX c. i CX, d. { CH, 
CJCHX CJCIL C]CH, C.]CX,. 

(CH, (CHX (ClU /CH, 

Since the hydrogen atoms in benzene are equivalent, the CH,- 
groups in the bciizcre molecule mtist be similftrly linked, so that 
n = b, and c = rf; in other words, the number of [K)s.sib|p isnmen 
18 reduced to two. Formula II cannot be accepted either, since it 
also fails to explain the formation of three isomeric disubetitution- 
productfl. 

There remains only formula III, in which mck mHton atom is in 
union wiih one fifpiriHifii ulom. Tlie question of the constitution 
of benzene therefore narrows itself to this: given a coinpound C,H,, 
in which each carbon atom is linked to one hydrogen atom, the 
problfm is to find a fomnila which account* for the equivalence of all 
the hydrogen atoms, the formation of three disubatitution-producta, 
and the abeence of double or multiple bonds. It is evident that 
an open carhnn-ehain formula eaniiot fulfil the prescribed con- 
ditions, since the hydrogen atoms attached to such a chain contain 




346 



ORGANIC CHEMISTRY. 



ing terminal and inlenne(imte CH-groupa could not be equal. Tho 
dx hydro^n atoms can only he nr equal value with a ckxcd chain 
of six C-atoois: 



BO 



CH 





OH 
OH 



EuffB&gBmmtoftbeCH-groups also Fulfils the second ooudilton, 
ae is ovidi'Dt from the scheme: 



I 





cx 



yox xclf }Jca uc^ jicB 

CU CH cx 

in which the compounrie C,H,Xj, 1 ; 2 = 1 : 6, 1 : 3 = 1:5, and 1 : 4 ar<r 
isomeric ; the formuliau ul thrcc isoiueis is, therefore, also accounted 
for. 

Ill 1hi« 9flipiii<=. t-acli carbon atom is In iiiiiou with one hydnj^ii 
atom mid two otlit-r carbon atoms, so that IhrL-L- bonds of each car- 
bon atom arc uccountwl for; it only rpniains to aawrtain the mode 
of liiikinic uf tlie fourth carbon bond. A hypothi-tictil explanation 
suggPHtt'd by AKMwTunNc, and also by FiAKVEH, is now regardc<l as 
aCforiling the moKt probable' explanation of the observed foctA. 
They awiunip tliat Ihp ilin^rtidii of the fourth Iiond nf each C-alora 
is t<iwnni.s ihr ci-nljn' of Uic hnizfni-ritiie, and Ihat each bond is 
kept in oquiJibrium by the olht^rs. their niutiial attractn>n catiaing 
the stabilitv of the closed chain. This ccn/ncfonnuta for benzene is 




Such a mode of Unking is vii)ki;<»vni in the faity senes, bo that it 



ISOMERISM OF THE BENZENE DERJVATiyES. 347 

and lacked by those of the fatty series. Hence, this structural for- 
mula not only accounts for the isomerism of the derivatives of 
benzene, but also explains the " aromatic " character peculiar to 
them. 

Nomenclature and Isomerism of the Benzene Derivatives 

264. The different isomeric disubstitution-products are distin- 
guished by the prefixes ortho, meta, and -para, or the positions of 
their substituents are denoted by numbers: 




1:2 "■ I ; 6 substitution-products are called ortAo-compounds. 
1:3 = 1:5 „ ,, „ „ T?i«(a-compounds. 

1:4 „ „ „ „ para-compounds. 

The number of isomeric substitution-products is the same for 
two similar or dissimilar substituting-groups, but not for three. 
Three isomers exist when the three groujw are similar : 






X 

Adjacent or Vjcimil Sjmmetricftl Asymiuetricail 

1:3:8 1:8:5 l.d-i 

When one of the groups is dissimilar to the other two, different 
vicinal derivatives result by substitution at 2 and at 3 respectively, 
and, for the asymmetrical compound, substitution at 3 produces a 
different compound from that resulting on exchange at 4. For four 
similar groups, the same number (three) of isomers is possible as for 
two, since the two remaining hydrogen atoms can be in the ortko- 
position, mefo-position, or para- position to one another. The 
number of isomers possible in other cases can be readily deter- 
mined. 

An alkyl-radicle or other group linked to a benzene- residue, as 



348 ORGANIC CHEMISTRY. 

in C,H,.CH„ or CA-CH,-CH,.CH„ is called a &ide-chain, the 
benzene-residue being called the mtdeus. Substitution can take 
place both in the nucleus and in the side-chwn; when in the former, 
it is usual to refer to the ■position of the substituent relative 
to those already present, the determination of which is called the 
determination of position, or orientation, of the substituents. The 
methods adopted for this will be found in 362 to 366. 



FKOPEKTIES CHARACTERISTIC OP THE AROMATIC COU- 
FOUNSS: 8YBTHESES FROM FATTY COHFOUNDS. 

365. The saturBU>d hydrocarbons of the fatty series are not 
attacked by concentrated nitric nr sulphuric acid, and bxit slightly 
by oxidbing-agertB ; their hftlogrrn-siibslitnted derivatives react 
very readily. The aromatic differ from the aliphatic hydrocarbons 
ill all these points. 

1. Tlie aromatic hyflrocariionB an? readily attacked by concen- 
trated nitric acid, with formation of nitro-f impounds : 



C,H,. | H + HO |NO, = C,H,-NO, + H,0. 

Iiiiri>b«imoe 

"On reduction, these yield amino-iierivalivcs, which proves them to 
be true nitroeomimunds. 

2. On treatment with concentrated sulphuric acid, Uic aromatic 
compounds yield eulphonic acids : 




C,H,- H + HOl-SO,H = C.HcSO.H + H,0. 

bcnxEnniuliiliuDlcacU 

The sulphur of the SOaH-p-oup is linked to a carbon atom of the 
benzene-nucleus, since thiophonol, CaH,..SH, also yields bcnzcDesul- 
phonic acid on oxidalinn : 

3. Tlic aromatic hydrocsrbonB with side-chains are readily 
oxidized to acids, the whole side-ehain lieinR umially oxidized back 
as far as the carbon atom in union with the nucleus, with formation 
of carboxyl, 

4. Chlorobcnzcne and bromobeoMnc have their halogen atoma 
so gtronely attached to the phenyl-Rroup, CoHi, that they arr almost 
incapable of taking part in double decompositions with such com- 
pounds as metallic alkoxidcs, saltSj etc. 

349 



350 



ORGANIC CHEMISTRY. 



S66. \'anoufl syntheses of aromatic from aliph&tic compouDds 
are known ; sonic of tlicnj arc vfn,- readily effected. 

1. Wlien the vapours of volatile fatty compounds ore led throu^, 
a red-hot tube, aromatie substances are amoug the products. Tha* 
condenwition of acetyteuc. C,II,, to benzene by this means is a 
typical example. A sj-nthcas of lienxcne from carbon monoxide is 
deacribeit in 816. 

2. On treatment with sulphuric acid, nectonc is converted into 
metiitflene, or 1:3:5-Lriniethyllienzenc (289): 

3C^,0-3H,0 - C;Hu. 

Other ketones condense »mitarly to aromatic hydrocarbons. 

3. When liberatetl from its sodium compound, acetoacef«lde- 

hydc, CHa-CO-CH, Cp^, at once chanjKcs into l:3:5-triacetyl- 

benxcQC, 

>COCH, 1 
C4iK-<^)CH, 3 • 
^^H:H, 5 

Acetoacetaldehyde can be obtained from acetone and formic ester 
byCL.\isEN'8i'omlen&al.ion-inet]iofl (203). 

Tho InTcrse roaction, tbe c&nvorsioii of aromatie Into fatty com- 
pounds, is also tM».<til>lc. 

I. Wlioii b« !)«)»»- vftpour i» l«d tlirougb a red-liot tube, aoetrleii« u 
produced. Since ncetylcito under the Mime coodlilonsiscODTened Into 
benwni^. it fftllow* ihnt lx)th reactions arc incomplete. 

8. Carcfhnt. 0„II,fOU), <i:3). is oxidiw^ by nitrons acid to 
d/Aj/f/Aij-y/.(rf.j*-(>'Mi</, t'OOU.L'(On>,-0(OH(,-COOH. Thecorialltu-- 
tioii of tliiii acid (ltftjfgilli)TC<i from iUi combinuiK witli two mokeiitMoC 
hydroxylamiiio or of phenyl bydrnzin a, whioh prorcA it to b« n dikotooc; 
iu«l swflilorHl liydrjite. OCI,- 011(01!),. pOMsue* nearly all the prop- 
artios of al'Johy<Io6 {tHH)- On reduction. dihydraxytaTtaiio acid yields 
tartaric nciil, while on tri>atmeiit with a cnncentmicd imlutlon of 
sadium liydrajrcvi) ftiilplii(«, it loses two molecule of carbon dioxide, 
and forma the sulplilte derirallvu of glyozal. 



BENZENI AND THE AHOMATIC HYDROCARBONS WITH 

SATURATED StDE-CHAINa 



Ou-nuDQfaetiire &nd iU B;-prodaots ; Tftr. 

267, Tho arnmalic hy'lrnrarhonH an- used in larfji? qiinntities in 
the manufacture of aniline dyes. aiiJ ary ohtaiueil fnim ooaUlar. a 
by-pixxliict in tho timimfaciiireof gas. A short dcscriptirtn of thig^ 
proc<«s will not, ]x oul of place, since it al«j j-iclils olhi-r products 
of great iuiportaiice in the manufacture of organic chcmicali!. 

CoaJ is Rradufttly heated in iron nr clay retort* of a Q-ehaped 
cross^oction . bring finally raised to a n>d heat: tho gases and 
vapours are rpmoved as cninpli-lely as p^isaiblt- by moans of vx- 
haustere. Coke remainn in the rctwrtu, and is crtiployed as fuel. an<l 
in many metjUlurB;i''-al pnmi-ssi-a, allhiiii.gh for the. latter purpose 
the coke has usually tu be pn-pan-d \>y special nicand. 

ITic distillate conlains three main products. 1. Gasee (illumi- 
nsting-gss). 2. An aqticouR liquid, cDnt^inin^ ammonia and other 
baaie subBtanecs, siicli as pyridine bft.sps. 3. Tar, Tliese are Bepa- 
rated from one another as completely as possible by a series of 
treatments. The crude gas is passpfl over iron ore. to remove ihe 
cyanogen derivalivefl. The piirifying-niateria! Ih employe<l for the 
preparation of potassium ferrocyanidc (843), an important soorce 
of the cyajiogon compoiindB. 

Tar is a lluek. black liquid n-itli a cbaracterisllc odour. Ita 
colour is due to susjiendeJ particles of carbon. It is a complicated 
mixture of neutral, acitlic. _and basic substances. The first an- prin- 
cipally liydrocarbons, chiefly belonKinp; to the aromatin Hc-rics. 
About 5-10 per eent. of the tar consista of aapht halene, and 1 -1 5 per 
cent- of a mixture of b4'nzene and toluene. Phenol is the principal 
acidic constituent of tar. Basic subcitanceK are only present in smi 
quantities, the chief being pyridine and quiuoline, and their homoj 
logucs. 

3SI 



AROMATIC HYDROC^RBOffS. 



ii3 



la the sjaitiesia of Friedgl ami (..'lUPW more thao one allcyl- 
group in genernll}' inlmituciMl, the Toonosubslitution-proOucts anil the 
bigber 8ub»tit utiuD-pruducU bving Bimultaaoouslr fomicct; tliv Uonw- 
logaee ar« soparetecl by fructionttl iIiatill»tioti. 

Tbift r«actii>u ccnostitules a luetLod botbi lor lliti buitiingr up (tnd 
brmlcin; down of il lijdroeaibon. When loliieno, ('•HcCHi, is Inatod 
with itLuminium chlf^ridv, Wnzctii;, Cdli, and xylouo, t'*U,(CHt>i. arc 
fomwU. The nlkyl-groupB of one Iiydrooarbon are exchanged for the 
hydroften of the otbor. TbU leaction cau alio be brouRbt tiboat bj 
thanetion of oosoentrared sulphuric acid upon aromatic hjrdrooar- 
boDi with a natuber of side^hftius, 

3. Like the satiiratcd tatty hydrocarbons, the aromatic hydro- 
carbons are obtfliin\l by (he distillation of the calcium salta of the 
aromatic acidfl with sotla-linte: 



C^,.|CO,ca*+ caO|H = CaCO, + C^,. 

4. Ileiizciie and lU homologucs can be obtoiiuxl by htatiiig the 
eulphonic acids n-ith sulphuric or hydrochloric acid, \h^ decom- 
position being facilitatc«l by the i»tniducti<m r)r Huporhvated Ht«ii.m: 

C,H,(CH,),| Sf>,H + HO lH = C,H,(CH,), + H^.. 

Thi.t invllingi cati bi> eiiiployed in the eepuratioD of the aromatic 
hydrocnrbotig from ihi' jinnillUw, Wh«n varmod with cunceul ralwl 
Bolphuric acid, tins formur iirc converted into sulphonlc wcids iwluhin 
In water ; tho pnmfiiiis are unaotwl on and are iasolublc in wator, so 
that n lucchAnlca] a<'i>aratio[i is thim |nMAihli\ 

Till* nmtliod win also he appHcHl to ihe si^iaratiun of the aromfttic 
bydrocnrbouB tbomsolvL'it, una: iraino oF tbem arc more readily coo- 
rert«d taloBulptiouic atiids Uiitii othort. 



6. Ity heating an alct^hol, aii aruriialio tiyd x>carbi>n, ant) zinc 
cWoridf at 270°-300°. The zinc chloride plays the part of a dehyd- 
ratiiig-agi'Ht: 

cji,|H+~Hoi.cji„ = cji,-c,H„ + n,o. 




iS4 



ORGANIC CHEMISTRY. 



IndiTidnal Mem'beri. 

269. Bonzcne and the aromatic hydrocarbons with saturated 
sltli-cliaiiis are colourless. Idghly refractive eiihatanpcs, liquid at 
onliimry tL-inperatunw, and pnwcsfiing a characlcristic odour. 
T1k->- an; immiscible with water, but nux ill all proportions n-ith 
strong alcohol. Some of th(^ir physical properties are iudicated in 
tlie table : 



1 Kane. 


Fomiuh. 




unSq^ 




C'.H, 

L-,H,-C1I, 
. ,, ^CU, 1 
■^•"•^-fH. 3 
C,[l.fCll.i.<):3;9) 

a.H..c,iu 

C.H,-CliiCII,), 

V II .^*'"' ' 


Bor 
no* 

189' 

164* 

IHtf" 
1&3' 


<l-874 («)"> 

o.sse (is*i 

0.881 (0*) 

o.aia (i4'> 

0.888 (0-1 
0-Mfl (16*1 

0-8ce<so*) 






I>ourupvlLt<tiKune (Cumcne). . . 
jvMvtiiyllaoiiniiivllwn acne 



Benzene was discovered by Faraday in 1825 in a liquid obtained 
by siibiiiitliiij; cuul-^ati to pn^esurc. 

Xylene, or diiiifihylbt'ii)!t'iH-, c-xii(t8 in tliroo istjtiioric forms; 
Tfi-xylirric in tliK priiifiiml toiistilueut of the xylene in tar, being 
70-85 per cent, of llic whole. 

The iHomerlo xylenes can only bo sepnraled with difflculiy; ili«ir 
boilirg- points lie vory eWo tngflhsr, Ihnt of o-xyl«iM being 14**, 
wliilo irt-xyluiie nnd j><:tyler« btjjl ttt 130° And 13S* mpcctivoly. 
ThU makes ilimr sepanilion by rnictioiiHl disiillalioii iniprAeiicjtl>Io, 
bill it can be clCe«tod by Iroatiug tlioiu with sulphuric acid at onli- 
nnrj- tempernturM; m-zjleiie and <>-x>*I«tiv gu into Bolutioii na gol- 
phonio ft(!i<I«, wiillp p-xyU-Tio wmdins undlMolvecl. The tnlpboDie 
acidn of the tnefa-corn pound nnd urMr'-«onipound e&u bo Hparatw] by 
frsoiioiii^l crysinllisAtiou of tliifir sodium sails, ibe <trfAo-salt cryslalli^- 

CymeM, C„H„, ia closely related to the torpones, C„H,„ and ta 
the camphors, C,oH,,0, Bince it can be obtained from Ihem in various 
ways. Cyineim is a coustitiient nt certain etbercftl oils, such aa oil 
vf carravxiy, oil of thyme, and ad o/ eucalyjitut. 



AROMATIC HYDROCARBONS. 355 



HydrogeQ Addltion-prodaots of the Aromatic Hydrocarboni. 

870, When Ibe aromatic hydrocarbons take up two or fonr hydro- 
gen atoms, they lose their aromatic character and acquire properties 
peculiar to unsaturated compounds (468). The centric bonds may 
be supposed to be broken, with formation of double bonds (BIB): 



H H 

H H H.f^'^^H, 



■KDi 



u 



K^ 



KNh"*'h 



H. 



H H 

Dlhf dro be iiwno 

Dihydrobemme, CtH., for example, reacts with a Bolutioa of per- 
manganate and sodium carbonate, and also adds on four bromine 
atoms. Tetrahydrobemene, C,H„, readily adds on two bromine 
atoms. I 

When six hydrogen atoms are taken up by benzene, there results 
hexamethylene, which melts nt 3° and boils at 608°; it has the 
character of a saturated liydrocarbon of the fatty series. Hexa- 
methylene, (CH,)^ or C,H,„ and some of its isomers, are pi'escnt in 
Busstan petroleum; they are called naphthenes. They can be i'ec<^- 
nized as addition-products of the aromatic hydrocarbons from their 
yielding nitro-deri vat ires of these hydrocarbons on treatment with 
nitric acid. They differ from the isomeric olefines in not possessing 
the power of forming addition-products, and in their stability towards 
Baeteb's reagent (ISS). 

Eexamethylene and its Iiomologues can be obtained by the catalytic 
action of freshly- red need nickel on a mixture of hydrogen and benzene 
or its homologues, the reaction taking place at a comparatiTely low 
temperature ^, 126, and 1S8). 

W. H. Pkbsin, Jun., has prepared hexamethylene synthetically in 
the following manner. Chlorobromotrimethyleno reacts with sodium 
etboxide, yielding a chloro-ether : 

Cl-CH..CH,.CH,-Br -h NaOCH. — C1-CH,.CH,.CH,.0C.H.. 
This compound is treated with sodium : 



aCltH,O.CH,-CH,-CH,.[ Ci + Nn, | -* C,n,0(CH,>,-OC^(. 



35^ ORGANIC CHEMISTRY. 

This doable etber ia tbeo treated with hydrobromia aotd, 

C,H,0-{CH,>,-OC,Hj + 2HBr -♦ Br.(CH^,-Br. 
With sodium, the reeuItlDg dibromide yields hezamethyleae : 



OH,-CH,— CH, 
CH,-Cir,-CH, 



Br 


Na 




+ 


Br 


Ka 



CH,— OH,— OH, 

CH,— OH,-OH,' 




MONOSUBSTITUTION -PRODUCTS OF THE AEOMATIC 
HYDEOCAHBOHS. 



I. MOVOBULFHOnC kUlDB. 

271. The formation of these f«nipniinds liaa been described 
already (26&); they arc produced by the action of coocentmt*d 
sulpliuric aciti upon aromatic compounds. In order to separate 
thera from the cxco.'B of sulphuriu acid, use is made of the ready 
solubility of thfir calfliuiu aiid barium salts In water; the proceas is 
mmilnr to the Bpparatioii uf ulhyl hydruypn sulphate from sulphuric- 
acid (60). They ran also be separated from thdr coiieeiilratc<i 
solution containing eulphuric acid I>y the addition of cotmnun salt 
until no more will tlisaolve, when the aodiiim salt of the aulphontc 
acid separates in the solid state. 'Vh\s h dissolved m water, the 
e<iuivalent quantity of mineral acid added, and the free Biilphonie 
acid isolated by exi raetinn with eth<T 

The sulphonic acids an- cnloiirlrw, crystalline substances, gen 
erally hygroscopic, and rrmiily soluble in water. They can be 
rrconvrrted into tlir iironiatic hydrocarbons by treatment al a high 
temperature with hytUvchloric acid, or with superheated slcain 
(268. .1). 

Most of the sulphonatfs ervstallize weEl, and are employed in 
the purification of tlie sulphonic aeid^. On treatment with phot* 
phoruH pentachloride, the latter are converted into chlorides: 

C,H,-SO,-OH - C,H,.Sa-Cl. 

The milpkonic chloridex are very stable ton'Rrds cold water, being 
but «lowly reconverted into sulphonic acids. 

Tlie stUp/iaiuirnnke are formed by the action of ammonium 
cjubouate un the chlorides: 

C,H, • S0,G1 -* C JU • SO, • NH,. 

They are well- cryatalli zed compounds; the determination of their 

3S7 



3fio 



ORGANIC CHEMISTRY. 



Individual Members. 

}^<mt>ehlor<^cnza\c is a colourless liquid ; it boils without decom- 
poRitino at 132°, ami hsB a specific grax'ity of 1-106 at 20". Mono- 
brnmtibmsene, B.I'. 157°, sp. gr. \-\9l ftt 20°. Monmodobemene^i 
B.P. iss*, up. gr. 1 .S61 at O". 

Bctizyl chtaridt. is a colourless Itijuid of stuppfying odour, inten- 
siiird by warming: it lioiis at ITS*^. ami hasiisprrifi<;p"avity of 1 • 113 
at 15°. licneyt iodide is prcparrd Ijv heating benxyl chltiridr with 
potaasium iodide; it melts at 24^ and dccompo^ee when boiled. 
It ha« a powerful -aiid uiiboaraljly irritAting odour, productive of 
tears. 



lodobenune, and other Iodine oomponndB, snbfttituted hi the 
DoeleUH, un add on twu atoms of ohinriiie, wiUi formation of com- 
pounds snoli as pJietij/tiodiiln chloride or iodfAtmetM dtchJoriilt, 
0*Ui-ICli. Wlica digtatod ffitbalkiitui, tbeae givo lotiooD-wmpoumf^, 
such lis iodoMlKjitfii^ C*UfTO, wbicb are amorphous, yellowisb 
solids. Wh&Q heat<xl, or oxIdtE«d with bleaohing-imwdor. these OOID' 
pounds yield iodox}/-<ompounds (German, fodovtriiinduu^t), 

SO.H.-IO =O.H.-I + UH.IO,. 
lodiraytwnteiM 

Todaxyftensene \% or3»talliD» and explodoa wbcn heatad. 

T)ie coimtituMon of these compounds is inferred from their readf I 
coiiv<.-i>ioii into iiKliilx^'iixerift. tijfs l>eiiit: elTected for iodoaob»niea« 
moans of potassium iodide. And for ttxloxyboniene by hjdrocenj 
dioiide, ■mth evolution of oxjrgeiL Tbno siitMlances wonld not be so^ 
readil)- <X)nT«rted into iodobenxene if tbe oxrgeu were attacbed to llw^ 
l>eiix«i:ii--nucleu&. 



<^ 



in. MOKOHTOEIC PHEROLS JUTD ABOHATIC ALCOHOLS. 



274. The hydmxyl-compounds of the aromatic hydrocarlKins 
display the same riiaracteristic difTercnce, occasioned by the utiion 
of the sulwtitueiit with the nucleus or with the side-chain bo 
the halogen derivatives (278). The Oil-group in phenoi (carbolic 
acid) .CgHj-OH, is in union with the micleua.and posseasea a chaioctcr 
unknown in tlip fatty serips. A enmptmntl suph as bemyt alcohol, 
C,H(*CH,OH, winwi* cijiLstitulion follou's from its oxidation to 
bonrnic acid, CJlj-COOH, displays moat of the properties cbsiao 
leristic of the aliphatic alcohols. 



PHENOLS.' 



36r 



I 



A. I'HRNOLS. 

Phenol and eoiiic of its humolo^cs, such as creaol, etc., are 
found in coal-lnr, by the fractional distillation of wluch they are 
ai'ciimulntcd in thp carbolic and creosote oils (267). They are 
isoliiterl by shaking these fractions up with caustic alkali, wliieh 
dissolves the phenols, leaving the hydrorarbons behind. They are 
liljerated from the solution nnlh Riilphiirir acid, and are then sepa- 
rated by fractional distillation. By far the larger proportion of 
the phenol found in commerce is obtained from this source. 

Plienol and its liomoloEuea can further be obljuned by the foUovr- 
in^ methoda. 

1. By fusion of the sail of a Bulpbonic acid with alkali : 

C,llj-S0,K + 2K0H - CHj-OK -t- K^O, + n,0. 

2. By tbt- aelion of iiitmiia acid on aromatle aiiuncs, a method 
analogous to the proparatiw of alcohols of the fatty series from 
amines (72). But whereas on acting upon an aliphatic amine with 
nitrous acid the alcohol is produced din'i-tly, in this rase ven,' im- 
portant intermediate products, the diiuoniuni compounibi (302), 
can be isolated. 

3. Ry the artion nf oxygen upon l)rnzCDC in presence of alumi- 
mum chloride, phenol is ft.niied. 

Properties of tb« Fhenola. 

279. The phenols are in some reupcets comparable with the 
t«rtiar>' alcohols, since in both llic hydroxyl is linked to a eurbon 
atom in direct union with three others, although in the piienols one 
of thede bonds ii of a special kind. IJke the tertiary alcohols, 
therefore, tlio)' cannot l^e oxidised to aldehydes, ketones, of ■It'ids 
coaCaining the same number uf C-atonis. The phenols <Adubit 
many of the charHcteriHtieB of the aliphatic alcohols; tlu<y arn 
oa|mble of fortning ethers, whon alkyl habdes reset with their alkali- 
saltit; they produce esters, forming acetates, for example, with 
acetyl chloride. Phoaphorua peutachloride substitutes CI for their 
OH, although not so readily as in the fatty series. Cut in addition 
to these, the phenols possess .ipccial properties due to thetr much 
stronger aeidie character. When describing the separattoD of 
phenol fn)in oarlioliu «)il (267), it was mentioned that they disscilve 
in caustic alkahs, formhig /Vcrinruicji, such as C^II^-ONa. The 



3<» 



ORGANIC CHEMISTRY. 



alcohob of the fatty eerios do not possess this property in tlie sam€ 
degree. Those which arc iiiRrthible in wntcr do not dissolve in 
caustic alkalbi, and are only convcrtetJ into metallic aIkoxidi>s bj' the 
flplinn of ihp alkali-nietals. This increase in acidic character can 
only be (iccasiotKHi by the iircsicncn of the phrnyl-gmup; in other 
words, tiie jiiu-nnl-ffrvup luia a more nttitUivc cJiaracier than an atJcyl- 
graup. Iti other rcipTCts, Ihc pheiitjls arc weak acids; their aqueous 
solutions are bad conductor? of electricity, and thopKcnoxides are 
decomposed by carbonic acid. 

It is thus seen tliat the prnperties of the hy<lroxyl-gn>up are 
considerably nio<lificd by union with the phrnyl-iaT""ip. Inversely, 
the itifliicncc of Ihr hydnixyi-prtrnp on the U-nzeiic-nucIeus is 
ecjualiy marked, itiakiiiR the ri:iiuiiim)|; hydroKcn atoms iimch more 
readily sulwtitulcd. Henxene is only slowly attacked by bromine 
at ofiiinary temperatures, but addition of bromine-water to an 
aqueous solution of phenol at once precipitat«i trihromophpnol — 
a reaction employed in il.s ipiantitativc cstimatioii. Thewmver^iion 
of benzene into nitrobenzene ncccssitattsi the use of conccntrati-d 
nitric acid, but phenol yields nitropiiciiol on treatment with the 
dilute acid. I*heiiol.s are also much more readily oxidized than the 
aromatic hydrocarbons. 
i~'*On distillation with xinc-dust, the phenols are reduced to the^ 
I correspoiidiiig hydrncarbuns. They can be delectctl by the forma- i 
j tion of a violet colouration when ferric chloride a added to their I 
■(_a<iucou8 solutions. '"^ 

IndividQal Members. 
278. Phenol, or carMic acid, is a (rolourlcss substance, crj-stal- 
lizinK in long iici-dles. It melts at 39-6", unci b<i)il» without decom- 
pcwitiou at 181°. It has & characleriBtie odour, and stn^iy: antiseptic 
properties. It was formerly largely employed in surgery, but to a 
gn-at extent its place lias been taken by mercuric chloride, or 
ccirrodive Miibliuiati;, HgCl,, Phenol is soluble in water, 1 part dis- 
Bolving in 15 at 16°; it can also dUsolve iivatrr. On account of the 
email molecular weight of water, anti the high molecular lowering of 
the freciiing-puint of phenol (75), a aiuttll perceutage of water cai 
phenol to tw liquid at ordinary tempernture.s (14). It follows fror 
the ei^uation ,!iV/ = 75, in which M is the molecular weight of Wftt 
(IS), that .4 , the lowering of tliK freczing-poiiil occasioned by 
presence of 1 per cent, of water, is about 4'2^, 



PHENOLS AND AROMATIC ALCOHOLS. 



363 



The hydrnxytoluenes, Cn,-C4I,'0n, are called crtsols: tboy jirc 
preecnt in coal-tar, l)ut are usually prepared from the corrL-spDrul- 
i«g amino compounds, or sulphonic acids. On oxidation, they arc 
completely decomposed, but when Uie hydrogen of the hydroxyl- 
group \i replaced by alkyl or acetyl, they can, likf toluene itself, 
I>e oxidized to the corresponding acids. Tlie creaols resemble 
phenol in their behaviour towards bromine- water. jvCrcao/, 

CH,<f X*^' '^ * decomposition-product of albumin. 



Thyittol, which is also usc<i as an antiseptic, is hydroxycymene, 

4- 



\CH(CH 



:ccH,),f- 



Acid sulphuric cstcn of pti«tiol nre prasoiit In urine ; thej rcaalt 
from tlio Tlih noil tilt ion (itutrcfiictiDn) nt iilljiiinitjs, since the quautily 
of tbem prctcut ilopcnOs upon tbo oxtunl of tkia process. 

n. AHOMATIC ALCOHOLS. 

277. A type nf these coiiipiimdK !« iurtuyl alcohol, CcTTj-CHjOII, 
which possa'wns nearly all ilic properiics of un alipliatir alroho). It 
can be obtainnt by tn-atincut of benzyl eliloridc witti potafisuim 
acetate, and sapomficotioii of the ester of acetic acid Ihu-s farmed. 
It reacts readily with phoephonw pentachloride, yielding benzyl 
chloride, and forma esters, ethers, etc.; being a primarj' alcohol, it 
can be oxidized to the correHpnndtng atdchyde, bemaldditfde. and 
also to htmoic add. It (litT<'r» frtmi the aliphatic alcnhnlt in its 
behaviour towards sulphiirin acid, which causes resinificatioo, in- 
stead of the formation of th» corrcspunding sulphuric ester, nenityl 
alcohol poeMSscs no phenolic properties; it is insoluble in alkalis, 
and docs not yield the characteristic phenol colouration with ferric 
chloride. 

lieneyl alcohol is a liquid which dissolves with difficulty in water; 
it boils at 206°. and possesses only a faint odour. 

^« - «• 17. STTLFRtnt DESITATITU. 

Ttiiophenai, C,n,-Sn. cnn be obtaiDed by heating phenol wUh 
pbMpliorus p«nlasu1i>bid<!<, 1>,S^ or by reduction of Ibo chlorido of 
bcnieoMu I phonic acid. It bag all the propertiei of iIiq mvrcaptntii, 
partk-nlarly tite power of forming wlt«. Like taoit v<4atil« •alphtiT 
MHopouiiils, il has a diaagneobla odour. 



MONOSI TRO-DERiyATiyES. 



3«5 



For the preparation of aromatic nilro-coinpmirKL'*. The substaiit'e 
is treated with n mixture of nitric and sulphuric acids: 



C.H4- 



•XO, = CANO, + H,0. 



.^^rtJriomed in the nitration would dilute the nitric acid and 
nmrff ^ ictlon if the sulphuric acitl were not present. The mure 
alkvl-croups there are in union with the benzene-inicleus, the more 
readily is the introduction of nitro-groups effected. 



FropttTtlM. 

280. The mononitro-cnmpound-s are very gtablo. and can be 
distillerl without decomposition; their niiro-groups are verj- finnly 
attached. Vnlikc the primary and peeondary nitro-compounds of 
the fatty serjea, the oroniaiic nilro-de-rivatives do not contain hydro- 
gen replaceable by mctalH, since the nitro-group in them is linked to 
a tertiary earbou atom; tsueb an exchange is therefore impu.'sible 
(76). On reduction, the nitro-eompoimds yieki aniinE«, and the 
reaction can be so carried out that various intenuediatc products 
arc isolated (289). 

Moat of tlie nitro-com|)ound3 have a pale-yellow colour, and an 
agreeable odour; they ore usually liquids heavier than water, in 
which they are iufioluble. They arc volatile with Bteam. 



Individual Hembera. 

jVfc(ro6fn»rw ia manufat'turptl in large ijuantilies in the aniline- 
dye industry. Cast-iron vi-ssoU litteil with a stirTing-apparftru.s, 
and kept cool by water, are employed. They are charged with 
berutertc into which a tuixture of nitric and sulphuric acids is allimvd 
to flow. At the end uf tlie reaction, the iiitrobetiztme flouting <m 
the surface of the sulphuric acid, which contains only small tjuaiiti- 
Ue^i of njtrie acid, is wuahed with water, and purified by distillation 
with steam. 

NitTobenrene Is a yellowish liquid, with an odour resembling that 
of IjJtter almonds, for which rL'aatm it is used in perfumery. Its 
boiUug-tx>iiil is 208°, its mclting-poict b-h", and its specific gravity 



3W 



ORC/tNIC CHEMISTRY. 



1 • 19S7 at 25". Ita pn'paratioa od Uie lari^ scale is carried out in 
order to obtain aniline by its ro<luctioD (283 and 292). 

SUrotaluttirs. — When tolufiie w nitrated, the chief products 
are the wr(Ao-c(>in]5ouiid anil para-nompamvi, the mdjt-cnnipound 
being only fnmitnl in Iratit-i*. NS'hii'H i>f the uvo idoiiifrs is i>n«luced 
■□ greater quantity dcpL-nds upon iht-- iiti-thcid of lutratJon unploycd 

OH 1 

Vam-nitrotoluene, C,li, < v,^ a< is iM>Ii<l, melting at fil", and can be 

obtained pure from ilte liquid inixlure of tho isomers on cooling; 
tin- pn.:paraliuu of llii' pure ori/io-comixiund '\» niom troublesome. 



PbeDytBitrometliaae and the pMndo-ajcid». 

B81. PhtiU'initromtthane, CtHfCHiNOi, is an nroinntic compontid 
with a nitro-gruuptu tin- aid«-uliitiii; iliin is vvr<)(!nl frDin ils (ormatior 
b}- lliQ acliuii uf boiixyl clilorMn or loiliil« «ii Kilvcr iiiirilu: 



CiH»'On,| tJH. Ag fyO«= C,H..CH,NO. + AgCl. 

It can bi) reduced lo Iwiistyliimiun, which proves It to bu n true nttrc 
oumpoiitKl. I'hetiylnilromclhtiiK'. ikti<] Wm (lurivntifM Willi aulMtitii<-ni» 
ntt.iciit^d in iliit niioloiui, pi)i<A<.'EJi \\iv rtntnrkivblo proptTly of uiaI- 
ing iti Iwo modiflealioiie wbit'li ar« readilj- t ntiiGfomii!d into oacli 
other. I'hfnyhtitrtiiiii'thnne ii« H litfiiiJ. whoso aqueons solution does 
not rvact vrith f«rrio oliloritlo. Wlit<n it io oonvertod into iu eodiom 
di'rirnlive by tho nation of sodium jilkozide, mid BubeVfiaoiitly set 
freo by tbc iiddiliuii uf a. sirotig mitivral acid, n ciyslalhtw MibufAnce 
of tho enmo conipoeiiion as iilifnyhiitromechane nepnntas oiit ; tha 
n(]uooiis solution of ihin anm)K)iiiid gives n coIoiirKlimi wii.)i ferric 
rhlwidp. AffiT sonii^ houre. Itit-ac crystalsiin? oomplctcly rcconTertwl 
into onliiinry litpiid {itiviiytiiiirumvtbniio. tl. is very ptotnbl4> that tbd 
eodiiim coni)Kiiiiid mid llic anst^blc modifimt ion corrasponding to U 
bnvu iIji.- coiiNliiiitioii 

CH..CH:NO.OH 

Thepres«no« of aliydroxyl-tETotip ixprnvi-il byihofornuilionof dibtfim-- 
hffdramtaie aetd on troatnicut' with bunutyl clilondo ; 

C.U.-CII:3If +CIOC.C<H,-.C,H,-CH-.Nr -• 



*ONa 

Elinjiuciliuia 



■ C.H.-CO— S— O-OCCFU. 
U 

IMbeailirilromuiUc M4d 



PHBKYLNiTROMBTHANE AND THE PSEUDO-ACIDS. 



367 



Aimtlior |iroof of Ibc prosuitoa of a hydroxfl -group is ihat JHnnuro. 
compoQiiilfl, unlike ordinary nitro-compounda, react rigorously with 
plifiiiyl ixocyanAle (M8) ai low teDiji«rH lures. 

From lh« ii[vi:rtliiifj it uiny bu ddJiiced thnt when pliffnylnilrome- 
IhHne. (',tff('ll,NO,. is rouTcrleO intu » luill, it first cbn[i);cs lo an 
bomerio moilifieniiun. luvi-racly. when it in net free fmni its Bodium 
cotiipouiid, ibe iso-moiliUcation is tint producdd, aiid slowly cliuugea 
to tlio ordinary fiiriu. 

Tho dJhilv AciiiH>us KOUiliun or llio inrfo-ititro-dcrivnlive of plicnyl- 
iiilrnmcihanc hffards n strikiDg example of lliia phaaoinoiinn. Tliis 
iiomptmiKl is eolourlesB, but ils sodium salt has a dwp-yellow «o)otir. 
Ou lliu itddilii>a of an cquivnlout quiintily of bydruutilorio Hcid lo its 
dM|)ly linlod •olntloii. ilie yollow cnlour diMppoara Ki>m«wliiit slowly, 
iadicaliog tbo vonvcrsiou of llio isi>-i;oiDpvuiid iuto llio uorroBl. 

TliBdisctmi^sor tlioi'i^biir Is altviiik-il by iinollivr pbcnomcnan ; 
tfae electric coiwluciivity of tlio l»|uid ia considemUy Rrealer iinuio- 
dlatnly after ilie addition of Iho liydrcclilorio noid than it u wvprnl 
miiinles litlor, >vlieii tbc colour Ijfis Doarly \aiiislicd. Tlic cx|ilHiiiitiua 
of lliis is lliHt iliv iHO-form in a true acid, and Is IlKTufore a pomliiclor 
ID aqueous aolutioii, wlule tlio solution of tlio uortoal muditicatlon is a 
noQ-oouductor, and tbvruforu [himosu-s tio acidic ohat^cier. 

Coiupoutids which cbaii|;« to an isi>->i>odiDcatioti ou furuintiaii of 
motHllindBrivfiiivea. are called ntetidti^eii/s . In addiiion to iilu-iijl- 
nttromotliuTmaud its niig-suUtt Itutt-d derivatives, other psoudo-ocidt 
are known, most of wliicb nro Tiiiru-cnnipoiinds, 

Bcftidvs Hid propurti<« itidieatvd above, the pseudo-acids poSBess 
otlicnt by wbiclj Ihcy mny bu di-l«M7tfd, It liiu just lieenatntcd Ibat 
tli« nddilion of a atrann; acid to a pseu<l<>(icidfla1t litinrtiti-^tlivp^iTudn- 
acid, and Hint it ia slowly coinei'tcd into tbd noTniid iiiudilu^ittJOii. 
IiiVL-rst-ly, Itio addition of an i^iulYaloot quantity of caustic alkali Co 
tbe iiorniiil mndincailon nwiUts in its )^a(Iu:d u«utra1ixaUon. This 
'*8low nvutralifflition" ia a characteristic of lh« pseudo^aoids. 

Aiiotbrr crlixrlnn for tbein is illustrated by dtiiitro«thai]e, witldi, 
aftor boing litK-riitcd from its sodium salt in accordnoca with, ibo 
equation 

taoiiinlLroriliftuii 
is BO rapidly converted into the notxanl compound, CHi-CH<jfQ'i 

lluit a cbnng« il] lltu i-leotric conductivity of ibo solution can scarcely 
boobocrved even at 0*. Tlie cieutrat refiotion of tl»onlkiili-derlvativ<« 
of tho nonconducting or weiikly-condiicling hydnigcn comiKMind 
DDTcrtlicItrss iiidicatei) the «j;intvuco of a |«eiido-acid. An acid which 
, i> BO weali that its solution is a bud ooiiductor of cleclriclly. yields 



368 ORGMMC CHEMISTRY. 

AlluU-«dU which ond«rgo ttroDji hrdrolftk dusocklion. and th»r«- 
for« hate astrongljr allcaliiw nnctioii ("Inorguiio Cbemutry,*' tU|. 
Soob a •nbstHDW as »oiiliodttiitroetliaue, whow &oluti<ra is uot alkalmi;, 
m»l therefore be derived from an acid oiher than (linitroeiliaiip, »iiu« 
thi« MbMance hat a MMitral reaction aod 1« a ooo-coiidQCtor ia aquo- 
oos eolutioo. 

Among the other raethoOa of det«otiDg pModo-aeids, (be adding oa 
or ammonia maybe [DentJoneO. A irDeacld. w ban dlaaolTed in banzda* 
or«DO(h«r bydrocaTboo, oombiDcs tnttaaianMiuly ihth dry aounonil 
to form aa inaolabte ammoDiuiu salt. A pseudo-mdd. on Ibecootniry, 
either does not add oa Ntli, oroaly»Iovrlr, being ioth«lattvrca&o firat 
eooTerted into a true acid. 



TIL MOnOAHIHO-COIIPOnilSfl. 

282. The amino-compounds of the aromatic M'rips, with the 
NH,-group attach«l to the ring, are almost exclusively obtaiiiml by 
reduction of the cnrrrapoDciing nitro-compoiinds. Ttiis is effected 
by the action of tin and hydrochloric acid, irou-fiUiigs and acetic or 
hydrochloric acUl, or by other rea^cots. On the manufacturiag 
Bcalo it te ii£uaJ to employ iron-filings aiid liydroclUuric acid. 

Amines can be obtained from phettoU by heating tJicm at 300'^ 
with ammonium zinc chloride. 

The aromatic aminos are colourless liquids of high boiling-point, 
or sTilids, and have a rharacterislic odour. With water, the ali- 
phatic amines form stronger bases than ammotiia, but the aqueous 
siihitiuiu) of the aromatic amines pasaess only weakly l>a.'uc pro- 
perties; thus, they do nut turn red litmus blue, aiul !iearc(>ly con- 
duct an electric ciirreut. The aromatic amines yield <ialt«i, how- 
ever, althoufrh tiiese have an acid reaction in solution, on account 
of partial liydrolyas. The ne|:fttive cliaraeterof the phcnyl-group, 
already alluded to in coitRecti<m nith phenol (376), coo^dcrably 
modifies the nBtun> of the ainido-gnmp ; the liehaviour of diphenyl- 
aiiiine and t riphenylamine in particular betrajn this influence. 
With Htrong acid:i the former can yiirld ."uilta, which, however, aro 
completely hydrolyzcd by addition of much water; the second no 
loRKcr uiiitoj^ with acids. 

Substitution of the amido-p^iup for hydrogen produce* the e&mo 
effect u]K)n the benzene-nucleus as substitution of the hydroxyl- 
grotip for hydrogen, niakinjE the rest of the hydmpen atoms of 
the nucleus much more easily replaced; thus, aniline is mUilj 



MOftO^MINO- COMPOUNDS. 



3*9 



converted by bn)raiiie-waler into tribroinoaniline. Moreover, the 
amines aro much niura reatlUy oidJized tliari the hyJruoarbons. 

By uicaiis of an alkyl li&JiUi', the Iiydrogeo atoma iu l]i« aiuiito- 
group of the primary aromatic ainiiies, like those ui the aintdo- 
group of the primary aliplmtic amines, can be replaced by an alkyl- 
group: 

C,H,NH, + CH.I - C,H.-NH(CH,).HI. 

Secondary and lerliary bases and also strongly basic quaternau^ 
armmmiuin basos, sucli as C*K6'N{CH,),-0H, are known. 

The anilitit-a are ilL-rivativos of aniline. C'bHj-NHi. and its horao- 
logues; lliey ore acid amides, in which one aniido-hydrogen atom 
is replaced by a phenyl-group. AtxianUidc. CaHcNH-COCH^ 
emplnywl att a fobrifuge under the name " aiilifpbrine." is a lypp of 
these compcmnds. The aiiiliili'!i aiv prwluetd by boiling aniline 
with the correspondiog aoid; acetaiiUide ijs obtain«l by heating 
aniline with glacial acetic acid: 



CH^NHIH + HUlOC-CH, = C3fNH-C0CH, + Hp. 



UEKHTHirTKiN found tbat the velocity of formation of acetaDllidn 
it much Icse (or an vxc^tta of aniline tlixn for an excess of glndfil 
aoeUo noid, nlthougti uu llidoriitical ijrouiiils the velouicy at rorciutioTi 
ebottldbe lbc»in)« in both case*; for at each moment ft should bo pro- 
portional to the i^rocliicc of the concent nit iodh uf (lie glacial acclio 
aoid (v) and of tho anilino (■/), bonig thcpufore expressed by 

jf = A-oy, 
in which k is coii&tant, 

Tiio (li fferetit-a between liieory and eiperiment can be Tarioosljr 
exitlalaed; for iiiaiance, on tho ground that tbci reaction hi the two 
oases Inkea place lit dilforetit media. Tliu important isaueQce of Ike 
medium liaa been mentioned (Tl), 

Aldehydes react xrith aromatic amines with elimiiiatiou of wat«r : 






ronuAldi-tifiln 



M»thjton«<llphon]rlilliiniln« 



Primary aromatic aminfs show the rarhylamino iraetion; with 
nitrous acid they yield diazonium compounds (302). 





283. Aniline was first obtained by the dr>' dintillation of indigo 
{anil) ; hence il» name II is manufacturrti by the action of hydro- 
chloric acid and iron-filings on nitMKnaene conlainwl in a cost^iroD 
cylinder fitted with a slirring-apparataB : 

C^Np, + 3I''8 + 6UC1 = C,H,M[, + 2H,0 + SFeCl,. 



IS remarkable that in this profi'ss only about one-fortieth of the 
hydrocldoric aciil required by the equation is needed for the reduc- 
tion. This is probably because iron-filtnga and watpr are able to 
|i»,»eductJou in presence of fermu*! chloride. Lime ia added 
MM W tbe r&duction is complete, and the aniline is distillod with 
steam. 

AniliiH- 18 altio obtained by thf fk'rtPo-r«luc1ion of niiro-b«n;^ 
t'M (292). 

Aniline is a colourless liquid, anil, unless perfectly pure, turns 
brown in Uie air, the culoitr clianKe being probably due to the prcs- 
oDce of traceii of a\ilphiir eompountls. It is only slightly st^ublo in 
water; it boils at ISO'*, and has a Hpccific gravity of 1*024 at 1G°. It 
eau be reeonvertod into nitroljfnzfue by ctTlain oxidizinp-ageiils, 
variouti intern letllalt- product*, sueh as nilrowilieiizeiie, G,H,>NO, 
being obtained. Anilijie midergoes oxidation eoniewhat readily; 
lh« co[iip<iundr< tiitJi< ijbtaiiicd will be described luicr (389). 

An aqueous solution of free aniline gives a deep-violet colouration 
n*ith blea<;hLng-[Kiwder solution; an aniline Kalt in acid solution is 
colrtun-d tlar](-greeri to blnek by pntjissiiini dichnimate. These 
two n:&(aion.s, and that with wixhI (23S), M?rve a» U-sis for ftitiline. 
The bteucliiug-puwdcr reaction U particularly delicate. 



Homologues of AnIUae. 

Ortho'toluidine and pftra-^^/uidllM, CH,-C»H,'?«I1^ arc formed 
by the reduetion of the corresimnding nitnvcompounds; the <>rtho~ 
compound is a liquid, li.P. 199-4*; the pnra-compound Is solid, 
-M.P. 42-5*. The different solubilities of their oxalic-acid salts 
are made use of to separate them. 



! HOMOLOCUES OF ANIUNE AND SECONDARY AMINES, 37 1 

'■m-TfAuidine can only be'obtaiaed indirectly. p-Tolaidine is con- 
Terted into its acetyl-derivatire, 0Hi-0(H4-NH0iHi0, which on 
nitration yields 

0.0. 

NHC,H,0 

The acetyl-gronp in this compoand is split off by boiling with hydro- 
chloric acid, after which the amido-gronp is eliminated by the method 
described in SOS, 3. On redaction, the m-nitrotolaene thas formed 
yields m-tolnidine. 

The monoamino-derivfltives of the xylenes are called xylidines. 
Six isomers are possible, due to differences in the relative 
positions of the methyi-groups and the amido-group in the 
ring. Some of the toluidines and the xylidines are employed in 
making aniline dyes, and are, therefore, manufactured in large 
quantities. 

Secondary Anunes. 

284. Dipkenylamine, CgHs-NH-C,Hn is a type of the true 
secondary aromatic amines. They arc formed by heating the 
hydrochlorides of the primary amines with the free amines: 



C,H,| NH,-HC1 + H| HX-C,H, = NH,a + HN(C,H,),. 

Diphenylamine can also be obtained by the action of bromobenzene 
on potassium anilide, C,Hj ■ NHK. 

Diphenylamine is a solid, M.P. 54°; it has an agreeable odour, 
resembling that of some flowers. 

Diphenylamine is a very sensitive reagent for the detection of 
nitric acid, liquids containing which produce a deep-blue colonr with 
its solution in concentrated sulphuric acid. This reaction can only 
be nsed to detect nitric acid in the absence of other oxidiziug-sub- 
stances, such as bromine-water, permanganate, etc., with many of 
which diphenylamine also gives a blue colouration. 

The method of formation of the mixed aromatic-fatty amines, 
such as methykmiline, C^-NH-CH,, has been already indicated 



TERTIARY /iMiNES. 



373 



it of hydrochloric-acid gas, tiie alkyi-proups are split off, with 
fonnatioD of aniline and alkyl chloridL-s. Whon the hydrocfilorides 
of the alkyl- anilines are sirongly heated, the alkyl-groups linked to 
nitrogen are transferred to the benzene-ring; this can be explained 
by assitmiiig that deuompoeitiou iutu alkyl chloride and aiuliuc- first 
laln'i? filare as just described: 

1, c^/Nii(c,iij)na = c,n,-NH,,+ c,n^. 

This is tlifii foIlnwKd by tlie rcaclioo indicated in equation II: 
I 11. C,H.-i\H. + C,H,C] = CeH.<^J,^'fjp,- 

^1 Tliese roaetjons explain the formation of the hydrochInri<lp of 
^» jKtoluidine, by the interjicl km of metliyl alcohol and atiiliai! Iiydro- 
rhloride at a high t^'nippriiture. lly this process it is possible to 
obtain even ■pmlainrlhylatninohcnzcne, C„((;Hj)jNH,. 
^_ Uimethylaniliue and other dialkyl-anilines possess the remarlt- 
Hjkblo property of having their /vH-atom rcwliiy replaceable by differ- 
ent grouiJs, Thus, dimethylaniline reacts readily with nitroii» at^id, 



with fnrtnation of nitrogodimethytaniline, ( )JJ 



NCCH,),, eflfcetcd 



by the addition of potassium nitrite to the solution of the tertiary 
base ill liydroehlorir' acid. This iiitros<M;oinpound eryslalliM's 
in well-defiiied leases of a fine green colour. It melts at 85", 
and yields a hydrnehlnride crystallising in yellow needk*. On 
oxidation with pntasaiiini ^wrniianganate, the nitropo-group is con- 
■Srertcd into a iiitro-group, with formation of i^nitr&dimdkylaniline. 



C IL <^<^^i'> ^ 



4* 



On boiling w-ith caustic soda, the amido-group of nitrosodi- 
methylanihne is rompli^toly split off, with formation of dimcthyl- 
imuuc and nitruHuphenol: 



k 



C^.<Xo"»'' + H,0 - C,H,<5^^ HN(CH,),. 



NltnHKililielinl. 



This reaction ia employed in the preparation of pure dimethyl- 
I amine (72). 



374 



ORGANIC CHEMISTRY, 



The i^liydrogca atom of tlimethylarulinc can react with sub- 
stances other tluLD nitrous acid; thus, aldehydce readily yield a 
condensation-product ; 



C|,H,-CH 



Q + hIc &K!;- C.H.-CH[C^.N(CH^J.. 



The constitution of this cnmpound ui deduced from ita relation to (rv 
phcnrjlmclhatif. ('H(C,Ur,), (366). With dimcthvlaiiilinc, carbonyl 
chloride yields a p-derivativc of bcnzophcnonc, C,Ht'CO'C,H,: 



\ 



Cl + H 



Cl + H 



C:,H/N(CH,), ./C,H,-N(CHO, 

= CO , + 2Ha 

C,H, • N(CH.), \C„H, • N(CHO, 



When diniethylaniliii(>, and ottier analogous tertiary* amines, are 
treated with hydrogen pen)xide al ftO*-70°, ihey yield compounds 

C,H^N(CH,)^ 
Bueh as dimetkijlaniline oxide, t whom constitution 

O 
follows from its being remlily reducible to dimothylanilioo. 



CLaatemary Bases. 

286. Quaternary' bases are formed by the addition of alkyl 
hfllidcs to the tertiary arotnatic-fntty amines, artd treatment of the 
salts thus funned ftitli moist siKrr iixidp. These subelanccs are 
strong bases. On heating, they split up into an alcohol and a 
tertiary amine, wherein they differ from the aliphatic animooium 
base* (73). 

AUeiDjits have been made to Bpht up the qunternary Rmmoiiiafo 
hases con taininft four diflsimiUriirroiips into optically «ctivfl 00 iii|>oiK!nt«. 
These ooiupounds of the lypo SR,R,R,R.X, fii which X in aii aoul- 
rtuliclt', vruukl ovrc their optical ncLivity to ibv prEsonco uf na asym- 
melric nit)'0!fen atom. TliU tlLK!oiup(>SLliuti hiu Iwi.'n n-cently effected 
by Pope. Betut/tphevt/lailj/imeihj/kimniotiium hydroxide. 



B01T(0n,C.H.)<C.lI.)(CH.)(CU.). 



Q^ytTEHN^RY BASES AND BENZYLAMINE. 



375 



mUM vlth the strongly opticRtlj itctlro tJ.cnmphoR«ii]|)liai)[o Hvid; 
tlie salt obtniniMt in fnictioi»illy oryelallizLMJ from ncclonv, a solvent 
wkiob is not so likely Lo dmompose it into nlcohol urid tertiar/ \M&e im 
&oIvfinl8 containing n liydrosyl-groiip. By this mejiiia tlie bane can li« 
Bplit up inio lis dextro-rotatory »nd l»vo-rotalory comixment* A 
ooni])lclu <lc uiuii.it rat iuu of lh» jiosiLioii tiiid direotiou of the bonds of 
til* |i«HlAviiltM]t uiirogpti utoiii \m* ixil yd been glvt>ii. 

That certain tcrtinry amines poaseaa tho property of forming 
addition -prod nets nitli alkyl Imlidps, vrbilct others do not, is probably 
alao espltcnltlo on AtcreochGiDtcal grounds. TtiuR, to account for tfao 
fuel that, nithniigh lri|)ih«oyl amine niid diphenylnielhylaniiiie do nut 
form aJditiuu-pruducta willi methyl lodiiW, Iribt^uzytuiuiuc ia capable 
of doing BO, It is asKDiuoil Ibat the plionyl-groujtit of Mto liro former 
compouuds arc so sttuatoil iu rclnCiou to the nitrugon atom tbal no 
spara is k'ft for CIlil to approach it. If, liowover, ibo tliri'o benzene. 
nuclei of tripheny limine are removed to a distance from Ibe N'Sluiu 
by the iolroduction of three CTTi-groups. na in tribenzytamine, suffi- 
ei«fit apace ia left for CH.I to approach th« N-atom. 

Benzylamine. C,HjCH,NH,. 

287. Bemylamine is a type of the amines with Nil, in tbo 
aadc-chaiti. It can be ohtainnJ by the varinus tncthfHls einploycil 
in the preparation nf aliphatic amines, surh as the action of benzyl 
chloride upon ammonia, by which dttn-Tutjlamine and iribemytcmiM 
are alsu ftirnu-fi; uil'lition of hyilnjgcn to bcnzonilrjle, C,Hj"CX; 
reduction of phenylnitromothftnc, CoHjCHj'XO,; otc. Its iiiPthoilA 
of fomiatioii and its properties prove that bonxylamine belongs lo 
the primary ariincs of the fatty scries: thus, it does not yiold lUa- 
zonium compounds; and itsaqucousAolution has a strongly alkaline 
reaetion, proving it to be a much stronger base than aniline, iu 
which the NH,-group is under the direct influence uf the phcnyl- 
gruup. 

neoxylaniin? Is a li<[uid of ainmoniacal odour; it boils at iSo^, 
is volatile with steam, and has a specific gravity of 0'9S3 at Iff^. 
it abiiiorbs c&rbou dio.iiUc from the air. 



Culioalc Acid D«TlvatiT«i of Aniline. 

nt. Only a tow of t1>e numerous compounds of this claa can be 
described here, rfinisilurerinvir. CHtNU-UO-OCMI.. is formed by 
tb« iaterattioa of chlorocnrbonic ester and nnilino ; it is a solid, nod 
iiwlt4 ni 52'. Wbea distilled with phosphorus pentoiide, ii yields 



> 



J7fi 



ORGANIC CHEMISTRY. 



phtngl isocyanate, CiHt-KiOiO, a ooloarlen liquid prodoetlir* of 
tMn, which boils at 166*. It b aometimes nnployed in tti« dctcctioa 
oF OII-groiiCM or Kllt-groap* in oompounds, Riiics Id pivsmee of 
thoM, subfttituted urothuiw fend ur*a rospectivcl)' an obtained. VHh 
wXLet it };ieldaEjiD[ni*trical(f//iAr»y^f(rM, CO(NU-C*Q»}i, kcryttalUne 
•ub»laDC« melting at SSV <»>>. 

Salphor DeriTStirei of Aniljoe. 

Snlphiir dorJTstlres of Anilino, slmlliu- to tho eomiMilllda deectibed 
in 94ft HD(1 lU, are also knoKn. One of tboM is phenyl muMtard-oS, 
C,n^-N:0:S, which baite at 3S2*. It ia obtained b; boiling cJr;i/Wn^- 
tfihurea, CS(^\l-CJti)t, ii'iih hydrochlorio nciil : dlphenyllhloarea 
itaeK id formed by healing carbon dlinlphidc with anilioe: 




Tin. INTEaiCEDIATE PBODTTOTS DT THE BEDTCTIOir OF ABOMATIO 
niTBO-COMPOOHDB. 

289. On reduction, the iiitro-conipoimds of the aliphatic series 
yield amines directly, from wIiirK the alkyl-gmupa an- qilit off Iw 
oxidation; fthylamine, for cxamplo, B eonvcrtod into acetic acid 
and aminonia. In tho aromatic K«>ri<«, on the nther hand, iot«rm(s 
tliatt> product* fan Ix? obtained buth m the reduction of jiitrtMjom- 
potmdf^, and somclimns alsn iii thr nxitlation of thr amines. Only 
tlie compoundu drrivrd from nitrobi-nzrnn and anilijie will be 
described here, ulthough umucrous substitution-products of tlie 
same type arc kno»-n. 

In acid solution, the nitro-compounds are din?ctly reduced to 
the corresponding arainoderivativis, but in alkaline solution yield 
subfltanoes containing two bcnzene-rcinducs. Nitrobenzene yields 
in succcsiiun 



1. Nitro-compmmd 

2. Awjxy-compound 

3. Axo-compound 

4. Bydraio-cumpoimd 

5. Amino-Gom pound 



C,H,-N=NCJI, 
C„H,NH— NHCA 



390. AtOTjtbentene la obtained b; boiling Qitrobentens witb 
alooboUe potash, and ii also formed in th* ozldaifon of aniline vrilh 
potaaaium pernunganale In aloohollo solution. It forms ligfat-jellow 



REDUCTIOK-PRODUCTS OF NITROBBSZENB. 



377 



«78Ul8 melting nl 38*. When vartned with coDcenirated sulphuric 
Bsid, it is tmnsforaMid into hytlr<fX]/tu<Aent«n« : 



CH.X- — N.CIl, 



.c,n.-\=ycMi.-oH. 

1 l]rdnri)'*sc>beii»Dii 



It is readil}- attacked by vurioiu reduciDg-ageaU. 

S9t. Azobcnzcne, C^Hj'NtN-CjHg, IS ffirmed bythe reduction of 
nitrobfnzcni* with a solution of stannous chloriclp in excess of caustic 
potash, and also by dUtilling azoxybeiizene vritb iron-filings. It 
is prodti»'<l along 'vvHth asoxybenzciic by the oxidation of auUine 
with potiissiiim pprnmnganatp. 

Azoboname forms wellnlcfined, orangi-n'd cryslabt. niplting at 
66", and boiling without dfcomptwitiun at 295". It is n very stable 
compound, ami is insnlubkr iu water. Its ci>i;siitutioii follows 
from its yieldiof; aniline on rttluction. 

Jiydrazohemenc, C„H»'NH— NH ■C,Hj. is fonned by the action 
of zinff-tlust and alcohoiic pota.*h upon azobonzenc or nilro- 
benaono. It is a coiourlass, rry.st«llin(! siibstancf , and melts at 126°. 
Strong reduring-agents convert it into aniline; on the other hand, 
I it is reailily oxidizcnl to azobenzene, this transformation being 

^B i^Owly effected by atmospheric oxygen. It is also oxidised to the 
^^ aeo-compound by ftrric cldoride. 

I The most characteristic reat^iion of hydrazobeiizcno is its con- 

I version into benzidine, whereby the benzeu^nuelei are, as it were, 

I turaed end for «nd ; this is eflFected by the action of strong acids : 

f Thi 

I ofb 

L *^ 
■ 1 



^O^XH-Nh/o^ - H^-C,H.-C,H,NH,. 



tl jrdnuo ht-nvmn 



Bsutdiav 



That a dinminodiphenyl is thus formed is pmveil by th« conversion 
of benzidine into diphcnyl, C^Hj-CgH^. The aniido-g.xiups occupy 
the jxiro-po^tions : 

' ' ' ' >NH,. 



By reducing azobenzene in acid solution, benzi4line is formed 
directly. It is characterized by the sparing solubility iu cold watar 
o( its sulphate. 



■ai 



J78 ORGANIC CHEMISTRY. 

The amido-fcroups iit bcDxidiiis Arc proved in varioiia mifa to 
oceupy Itifi paro-po«ilion: for vximiple. a hjdraiobeiiMno whose 
p-hydKigvii atoms tiATe be«n aubstituled «nnnot be converted into 
bensiiliiiH. lii twrUin liislancw oompouiidB of ibis kind can umlfr|^ 
a remitrknblQ intramolGGvlAr trAQiformalion, known aa the Mntiflin»- 
trAnsronnaLioii. forming cIvriratiToe of dipheDylamino by the tDmintr 
of ouly one of tb« beozeDO-DUClci : 



p-AonUmiclobjrilnuDbeiunw 



p-A (11 III ciphanjrl'p-aociani htt^ 
piitnjtjBiInt 



Electro- redaction of Nltro-compon&ds. 

292. Thi-n* is reason lo believe that in tlie future eloctric 
raetlKxIs will bp uswl more and more, for the electric current affords 
a means nf varying the pressiire and cnrcentration of the c«;>m- 
jiuunds taking part iii reactions in the preparation of organic 
compound", which is not othenvTse attainable, Hyitsaid it is poe- 
sihle t" t'Pfeel ni?w syiilheaci) or to inifirove those alrwidy known. 
An cxplaimlion of the mode of altering this pn-ssuro and conceutra- 
tioii is uc'cessary liere. 

It wfta 8tat4.ti (258) tliut alteration in the difference of potential 
of llie electnides causiw coiiaiderahlo variation Ju Ihc pr««ure at 
which the dischargtsj ions leave the solution. In rwluction- 
|)mppR'«?M till- Mime effect is attain<Ki by using riiffercnt reducing- 
agent«. ^Tion a fotnpmnid yiflds a neries of intermediate products 
on In'atniciit with different reiiueing-agpnts of iiiereasing strength, 
this can abo In- rffccted by incrL-asiiig the potential at the cathode, 
where h>'ilrufien its evolved. 

Hcgarding variation m the concentration, it must be remem- 
bered that the electrolytic i)mceB8 takes place only in the immediate 
neighhourluHtd of the eleelrodeji. When the surface-area of thoi 
clpctrmles is alten-d, the strength of the current remaining tlie same, 
the number of ions discharged at unit surface varies ia direct' pro- 
I)ortion; it is therefore powsilde, by scleeting niiitable eleetrodcs, to 
cause the concentration of the iona discharged at them to ^-ary 
within wide limits. The "strength" of the reduciiig-ftgciit depends 
upon the (liffenmce of potential, but its eoncenlrution is controUe<I 
by the density of the current (1$9). In reactions in which the 



ELECTRO RBOUCTlOfi OP ftlTRO-COMPOUNDS. 



37S 



diacharged ions must act on one another, as la the synthesis of 
dibasic acids (loe. cU.), a current of higli deiimty \b necessary; oo 
liie other hand, in recluctiaus which iiuist take place a*) far as pos- 
sible at all jiartK nf the liqiiiii, largo cathodes, which giveacurretiiof 
small «h;n!iily, muat be used. 

Oa reduction, the Ditro-eooi pounds ultimately yield ainines, but 
a numl)fr nf iitti-nnLtdiatc! rtituction-products can be isolated. For 
this reason the electro-rpcliiotion of nitrobenaene and iw derivatives 
is of both thoorpticHl and practiejil iiii|»)rtanre; it has been found 
posable to gi\'e a (-(iinptete and saliefactoty explanation of the 
mechanism r»f this i)nHTe»i. 

A distinction must be drawn bctwrarn primary- and sccondaij" 
redurtion-pnKhicts. Tlii: primary pr<K.'cs8 is 



MLrObFMU'lir 






(•„Hj-N"HOH 

PtipnylhrdrnTjI. 






Th« |ir«-soii<w of nilro«obeiiu}no c»n tic (l«tecut(l liy tbo addition 
of hydnuylnmiiio to the liqwicl, with which it ruactB with loss of 
one molecule uf vnler, and formnlion of iJiitioiiium hydroxide, 
C^llfXiOH; on lidding •t-na|ililli(il, atiii»i-dv€ is priKliicod (SSO). Tlio 
fortniiiion of ptioiiylliyilroiylnniiiio aim lin provnl by nddinf; benznU 
dehjdv, n'icli which it yields bouzylidciici'liuiiyniydroxyluniiue: 

C.Ht-NHOH + <X;ir (:,H,= ll,0 + C.HjN OH-C.Hi. 

BiBiiuildrbyilo v. / 

On rapid reduction of nitrobenzene disftolvcd in nioderately con- 
centrated stdphime acid, with nddition of alcohol to increase the 
solubility, the primary prtn'<'ii!i just dnscriboii takes platre, about 
90 per cent, of the tlworetiral yield of aniline Iwlng obtaintil. In a 
strongly acid »tiliition, however, the phcnylhydroxylaniinc is very 
quickly converted into ;>-anunopiienol : 

c,ii,xHou - Hoc,n,-\n,. 

This sulwtjince is not further peducefl. Sinee phenylliyclroxylamine 
undergoes the same tnin.sforniatinn, thniiph niiieli more slowly, in 
presence of more dilute acid, it is evident that in the latter case 
the theoretical jncld of aniline cannot be quilt- ohtained, even when 
the velneity nfreiluction i^■ ureal. 

Jn alcoholic-alkaline solution the electro-reduction of nitro* 
beiixeno i* accompanied by two secondary proccssca. 

I. NitrawticnRcne reacts with phenylhydroxylamine, yielding 
Azoxybeniene: 



3So 



ORGANIC CHEMISTRY. 



C^,NHOH + C^,NO 



C„H,N NC^ + H^. 





In preBeoce of alkali this reaction prciccctU ituich nton* quirkly than 
thp further rciluctian of phciiylbytlroxvlaimni'. !hj that only small 
quantilios ■>f aniline arc formed, and higlitT ivduotjon-prwluots 
of axoxyhcnzpnc, <'hiof ainong thiwe being hyilraznljpnzene, obtained 
as the main part of thp yield. 

2. HytirajujlH-nzrni! is atlackcil by IHr unreduced nitrnljenzene 
with fnniiatiiJii of azolH^nwne and azoxy benzene : 

3C,H,NHNHC,H, + 2CeH,N0, - 3C,H, ■ N : N "CaH, + 
+ C,H»X NC,H, + 3H,0. 

O 

Since hydraitnbenzpnc in alkaline solution is qtiickly osicliEcd by 
atnwjspherii; oxygun to azobeiizcue, the yidd of the latter is very 
BOtxi. 

A much higher tvnsioii is required at the cathode to reduce 
hydrasobcnsciie t<f aniline, so that in atkalinr eulution the reduc- 
tion-process ceftsOB witli the production of the former. 

llABEit has conibiiifMl all tlu^He jiriniary and st'condar>' reactions 
in the followiiig scheme, the VL-nieal arrows Indicatiug primary, and 
the oblique ones secondary, reactions: 

,C,H,-NO, 



_C, H,- NO 



C,H,N;NCH. 








C.H.-NHOH 



C,iivNH-NH-C,Hj 



Fio. 7a.— RABBn-a Et-Bcnto-aEoocnoii Scnua. 



PHOSPHORUS AND ARSENIC DERJ^ATiySS. 



381 



n. PHEITYL-COMTOITRDB COSTAUflXO OTHBB XUMKKTS 

Phoiphonit and Arsenic Derivatiret. 

S9S. CoTnponndsof phoBphoms and nnenic with ATomatio fafdnv 
cnrbon:*, and hayiiiK const hut ions similar to those of the nitro^com- 
pouniJit, luo-compniiDdB, mid amlno-ROtnpAunJji, are linowii. 

Ph»tstUiwiftrn:rnr. CjlTiPO,, ciiniitjt be obtained analogoualy to 
nitrobn'^nEiHio, by the iiiiiM-ncllori of mutapltosphorlc acid and bciiwuei. 
It is prt'piircd by tlic ncttou of phrtiylphaafihinic acid upon ils cbloridu: 

Qni-POfOIIl, 4. C,H,.POCI, = SCBfPO, + 8HCL 

PUtiiTlpliiwplilak CIiI'OtIiI* 

ucId 

It is a whit«, crystAlliti«, odonrless ponder. 

Pheiti/tiihogphiur. CiITi-PK„ U obtaliM^ by HlMWttng p/wtphfn^t 
chlaridf, C^Hj-l'dj, wiih oloohol, in a current of carbon di«xiil«. It 
is a liquid witli ii vKi-j iiriictrniirij; odour. It cannot bo ubtaioed hy 
the nxluetion of phoephinohonjcnc. 

Phoaphdmizenf. C.D'cPiP'C.ni, is obtained by treating phenj'l> 
pbospliine with ph«epb«nyl chloride: 

{;[i, p Kvrir, |p-c,u, = c.Hj.P: p.c.ifj + sua. 

It ia A pale-yclIow powder, insolubie in vtaUt, nicoho), and cth«r. U 
Is «n«T:gettca)ly oxidized by vreak tittric acid, formiag photphenylous 

add, OPr-H . 

\ou 

Pboaplieuyl chtoridfl, 0,Hj-PCl„ the starting-point in the prepara- 
tion of these aud other aromatio phosphorus deriv.iiive», can be pre- 
pared, aa caa Its homolngUMi, by healing; arrtmnllc hydivicarlnMis wlllt 
ptaMpborus trioblorida and nluniiniuni chloride under a reflux-con- 
deiiscr. 

Ayainohemme. C^ll^-AsO,, is obtalTicd by tho elimination of watot* 
trora phenylarsinic acid. CgU^- AsOiOll),, under tho intluenoeof heat. 

Araftwitemem, OoOj.As : Aa-0,Hj, is formed by tho reduction of 
pheaj/lartenu: artde, CaHg-AsO, with pbodphoruua acid. It forms 
yellow iieodl4>Jt, and is coDVert«d by osidation into phcnylarslnie acid 
©.HjAaOcOII),. 

Osa|iarli«n of tlw Aronutlo DMrlyatlTM ol Nlirvgan, Fboipbonu, and 

AtkoId. 

861. Tlie following comtwundii iira known : 



Klirobenwiia 

„ c<n,po, 

AnIiioljeiiMiiv 



AM>1n*MMII« 

an,.p,i',H, 

Fbo«|il)olirD(ei]e 

anaoobenatDo 



Pbenrlunloe 

C4H..PH, 

ttwarlphoiphloo 



3Sj organic CHUMISTRY. 

SaiMtances In tlio flnt eoluniii mtty bo Inoked upon aa d&rived from 
Iho Hiera-atids. IIONO,. IIO-PO,. II<)-AM>,. by exehari((o «f liyfirosj-l 
for i>lK<njI. iiixl liL-iicu (.-iLUiiot linvi* acidit? proporl im. Thfi nitrngon Hciil, 
IljSO,, or ON(OH)i, corre)«]i»n<I in^ u> [ihinspliuric HCid, II,PO». luid 
snenic aci>d, II,.V>0,, is not krinv.-ri, ntiil Hucurtlingly iiitrnlXMtZL'nudocs 
not uaiU) nitli wiiU-r, wliilu iibosiiliiiiDbonzciiD nud nreiaobcoitcnfl yield 
111* oorr«!jn>m5iTig Jioiils, pbt-njlpliospliinio aaid, r,ITj.pO(0n)„ and 
pben>]&raiiiic ncid, C,ll«-<VsO(OHi,. Pliii»|ilioric nL:iiI dixfit not yield 
P,(\ on heating; arsenic nctd yttrlils A«,Oj. Siinllftrly, |)li<w]ihino- 
1>eiiEene oaiiuot be obtained by liiMtiiii;; pliciiylplioapliinic ncid, itliilfl 
phunjIarsiiiiL' neid tg cniiTorlod Into nmimbunzmio by litis Irt-alrnenr. 

Tbc mcttitxlM uf rormation of tliv coiopouada of the second column 
also differ grtnitly from oiiu anollier. Th^y aro all oulourcd, (be moet 
deeply limed being azobcni^uc. ^'itrobiiiizune imd ursLtiobuiuEetie 
yield aioU-nzi'iie nnd arsL'nobfiiizone on nHliiclinii; the oxygen of 
phd^hinoWuKt'iiv is l«o firmly lirikvil to phunpljorus to itdmit of tfaia 
reaction. On ri^iiicliuii vlib liyilrugvii, luobL-iizeiivyidtUpbuiiylHiniiitr; 
Cblorlno cuqvotU phospbobuoxoDe Aiid ArsciiobouBouftiuto lliocorrc- 
spoiidirig chlorine ilerivativex. C^tlj.pCI, and C,II,.AbOI,. 

The diffuronoo bofifvpn llie two compauiids iu Ibo last coluiun is 
diid to ihe .iiroi))! aflluny W'lwcM'n p1i(»phorui> nnd oiyjcen. Aniline 
ontitiot be oxidisud to iiii itcid, wliile pheiiylphuopbiiio is vury ruiidily 
cnnverled. uveii by ibc iwygi-n of the atcttospherc, Into jpAenyfjiAw*- 
phimti4<uHil, t',llj.I'0,II,. 

Aromatic Metallic Componnds. 

889. Mcrciirj-, (in, li>a<l, ami tiingiii^iuin aw the only metals which 
yield nromalic compuiiniU, nud Uivsn arc of much Xesa inij)or(ance (ban 
the metallic com [wunrts of ihofnKy scrips. M^t^r^-pht-n'/l^ IIg(C,U^„ 
la obtained by (bo net ion of Bodiiim auinlgum upon hromobenzj^nc. It 
\i ory3(al1ine, and reaotnblos lliu L-orrespoiidiii); alkyl-derivatives in ita 
stability when l-xpomhI !u air. WIiqii ila vH[K)iir is pasnoil tlin)n>;h a 
redhftl lulu?, it splits up into mert'urj' and di}ili«ayl; tho saino offect 
is parlinlly priMlucinl by tu dinLilhition. M'licn inercury n<:iiia(« ut 
lieatud wttU bunzuRC at tlU°. there nuniUs pbenylmorciiry acetiUo, 
CaHfllg-OUC-L'U,, the uculiu add tsnll of tlm biuw phenyltQeroury 
hydroiide. C,H,-Hg-OU. 

Aromatic maicacatiuu compounds arc referred to in S7S. 



SENZO'lC ACID AND IT9 DEBIVATIYES AKD HOMOLOOUES. 



BeDMic Aoid, C^Hj-COOH. 

298. Bcmo'ic acid can be prepared by a great variety of 
methods, of which the most irnt">rtaiit will bo iJcscribcd. 

i. liy the oxidatioa of aay arooiatic hydroearbon with a ade- 
chain: 

C,H,-aH,„.»-.C,HrC0OH. 

Toliifne is P])pcially 8cr\'i«eable for this purjjoee, since it can bo 
readily obtainwl. In Uw manufacture of IieiizoTc acid, toluene is 
not directly oxii.U/:fi:l. but is ireal^Hl at its boiling-point with clilorine. 
Bcntolrichloritk, CHj-CCIj, ia first formed, and on heating with 
water is converted into benzoic acid: 




Gl H 

b H 



OH 

OH - n,o 

OH 



c,H,-cooH + ana. 



Benzo5e acii! thus prejjared often contains trace*) of efJorob€mo'!e 
ociW,C.H,C1G06h. 

2. By the oxidation tif aromatic alcohols or aldehydes, Huch as 

benzyl alcohol, C,H»-CH,OH, or beazttldfhyde, C^C^Iq; also by 

the oxidation of alcohols, aldehydes, or ketones %vitli longer side- 
chains; in fact, from »11 pompoundH containing a side-chain wth 
one carbon atom directly linked to the bonKone-niieieus. 

3. By the irtrofluction of the nit rile-group into the benzene- 
nucleus, and hydrolysis of the iicmonitriic, CHs'CN, thus formed. 

iThe introduction of the nitrih^-uruup can be cffeetwl in two ways. 
(fl) By diawitiziiig aniline, and treating the diasonium salt with 
potassium cyniiidc (308, 5). 
(b) By distilling sodium benzenesulphonate with potassium 
cyanide: 
C,H,-SO,K + KCN = C,H,-CN + IvSO,. 



383 



iu 



ORGANIC CHEMISTRY. 



A. By the action of carbon dioxide and sodium ou bromobea- 
«cne, whereby sodium benzoute is formed : 

CJI,Br + CX), 4- 2Na = NaBr + CeH,CO,N*a. 

5. By the action of varinus dprivativoR nf rarbonic acid, instead 
of carbon dioxide lUtelf, upau benzene, subalances readily convert- 
ible intu ln-nKoTn oriel bfiiig fiirtncil. 

(«) Bcjifittno and curbotjyl L"bi(iridt_' roaot topcthrr in jirrwnce of 
aluminium citloridc, with formation of benzoyl chloride, the chloride 
of benzoic acid, and hydiYJchluric tund: 

C,H, 1H -f Cfl -COCl = C.HjCCX^l + HO. 

ll«U(o) I vlilurlde 

Benzoyl ohlnride is readily converted into benBOic acid bj- trcht- 
ment with water. 

(h) BcnKiriL- ami aluminium rhinmie react with carbamic 
chlnridf, Cl'CONH, (fonntid by passing i;arl>onyt chloride over 
h<^atcd flminonium chloride), yielding bcnzamide, the amide of 
Iwnzoio acid : 



Cj gH + al -COXH, = C,H,-CONH, + HQ. 



(c) Bromol>enH>ne is converted by stxlium and chloro-carbonic 
ester into bcazoTc ester: 



c.H,Br+a] cooc,n. 



+ 



Na Na 



CaH(-CO(")C,H, + NaQ + XaBr. 



Benzoic Mid is a oonstituent of many natural resins and balsams, 
such as (;uiu-beiizuin and Peru and Tolu balaam. It in also prcacut 
asliippuric: acid (200) in the urine of horses. It was funnerly pre- 
pared principally from gura-benzom, from which source the benzoic 
acid wvii Ba a m(<<licaiiii>nt is HtiU aometimca obtAined. It is & 
whit*? sdUd, rrj-sijiUizing in leaf-like cryatoln mchiiiK at r21'4*. 
It sublimes reailily, anil b«iiU at 2.50"; it can l)e purified by dixtilta^ 
tion with steam, with whicti ib is readily volatile. Its alkali-itulLs 
dissolve easily in water, while must of those with other bae«a aro 
only solubk: with diOiculty. 



BENZOIC ^CID. 



385 



Tb« solubilit; curve (" InoTj^Dio CtiomUtir," nS) of bensolo 
has been tbo subject of cnr«fiil invcstigntion, en ACOOUnt of itA in- 
tareBiiag c!iar«cu>p (Fig. 78). The solubility inoreaaes Bomewliat 




O — ^ «•«■»!«■( I/O' no ULf 

FlO. 78.— SOLfBlUlT CDKVE 0¥ BttKZOlC ACTD IS WATER. 

mpidly vrllb increajw of HftniKTftture ap to flO* (AB). At Ihta tem- 
perature, tbo oeid tnclta bcncalh tlic water, bo thitt two Ii(|ai<]H roAult; 
one is nu aqiK-ouB aoltition, contAining IIW of acid (point fl); tha 
otiier cuDBiats itrinci pally of ilie ocid, of which tl contains 95-kP< 
{point D). Above thia L«in|M!rnture an t-ffect like Ibat dc-seribed in 
74 is prudiici^d: lli« uiutuiil Hohibility of tb(«e lajere in roproflculcd ia 
IIm! i>nrt JtCt> of Uio cupvu, of which BC corrofiponda to the »quoou8 
layer, and DC to ihc acid one. Tiie coTiiiMisilioii uf Oie iwo layers bp- 
«oiiiea more and more aliko la tho tompdrnturci riw«, sinew the waler 
diflsolvfls mom bensolc add, iviid the iit'id mori! wator: at 1 16' tbey are 
Idcntlcftl in composition; thai la, tlie liquid baa again bocome licMno* 
geoeouB. 

If inopu benzoic acid is ad(l«d to thonoidlayoronly.ntflO'. itisneo- 
essary to raise the teiuperntin'e in orrlcr lu keep »I1 iho ncid fuacd; tbo 
line I>F is thus obtained, eiidinj; at F at the tucttlngpoint of pure 
bonJHjIi; tieid, I2t-i'. TSF therefore repDMonls the moltiiig-poiut curve 
of the Hcid, oil lulditioii of h)croasiug amounts of wnter. 

Derivativei of Bentoic Acid. 

SW. Boixwjl cUoridr , C,H,'COC1, can be obtained by the adion 
of phoephot^s ppntucliloride or oxycliloridc iipoti benzoic ocitl, or by 
the method of 296. 5a ; it is a liquid of diaagrrcable odour, and boib 

pr 

at lft4^ It is inajiufaclurwi by ti-eating benzaldchyde, Cellj-CQ, 

with clJorine. Uulike acetyl chloride, which is rapidly docom- 



3W 



ORCAMC CHEMISTRY. 



posed, it is \'crj- slowly bcI<h1 upon by water at ordinary tciupi^ra- 
turcs. 

Benzoyl chloride is employed in the introduction of tJio benzoyl- 
pDup, C,H,-00 — , into compounds. Tliia Is readily effected bj- a 

mcthoti discovered b v Bat-masn and i-ViiniTKN . whioli consiata-ia 
shaking up the substance in alkaline iwKition with bciizoyl chloride. 

Bntzanitiik. C,UjCO — NH-C,IIj, is prepAred by dropping sisnlt 
qunnlities of caualic poiiuli Aiid iM.-ni'^ylcliloritleintoanillDe, a.w\ slink- 
ing lli« miiliiiv, vrbich id kept cu<jI. Finitlly, oiutlc potnith is ntUlml 
whh constant itliakiiig until ihustodlof U^tizuylcbloridotiiis vnoLshcd. 
Tbe bcnzatillido U colloctutl on n filter, and is obtained perfe«11y pure : 

c,iij-xn iTTci.coc'.H. + Kou = c.Hj.xncJOCin. + Kci + h,o. 

Brmolc anhydride, C,H,C0"O'COC,TI„ is formed by the inter- 
action of & iienzciatt; and benzovl chloride: 



C,K,COO |Xa + Cl| -Oa.'JI, - KaCl + CA00-O-COC.H,. 

At ordinary- teniperatures it is verj' stable towards water, but ia 
deeoin[H»Pil when iMjiled wilh it, yit'lding l)pn7.oic acid. 

The formation of ethyl bctuoiUe is ttoinctimcA employed as a test 
for ethyl alcohol, Hince it poesiasscs a charucleristic peppemiint-like 
odour, 

Benzamide, C,H|,'0ONH,, can be prepared by the action of 
ammonia or animnniuni rarbnnate on benzoyl chloride. It ia 
crj'Btalline and diniorphoiis, melting at 130°. It ffa.s stated (104) 
tiiat, on account of the influence of the negative acetyl-group, the 
hydrogen atttms of the amido-group in aceta-midc are replaceable by 
metals. Bensamide dispUiy» tliis property to an even greater 
extent, this being dye to the more negative character of the bensoyl- 
group; fur the veIupb of the dissoi'ialian constants for aoetie acid 
and for benzoic acidrespociively are ii = 0'CX)18and A' ^ 0*0060. 

Wlicn tho silver eonipounj of Vniamide is IrcalM with an »Ikyl 
kxlido at ordinary lempcmtun-s, an O-etlier, V/uolc tmituxHur, 

CaH^'O^uu* *) i> formed. Ttie conBlitation of l)ii«-8tib6tAO«o b 

provfid t)y itR yinlding ammonia and alcohol, iitst«'ad of ethylamiue 
atwl twazoto acid, vben treated with alkalis. When, liowever, tba 



BENZOIC ACID AND ITS HOMOLOGUES. 387 

silver compound is treated with an alkyl iodide at 100', a N-alkjl, 

CgHj-O^Ji ' ', is formed. This is proved by tlie decomposition of 

the latter substance into ethylamine and benzi^Ic nciii, so that the 
silver compound must havo a different constitution at ordinary tem.^ 
peratures and at 100' (MT). 

Bemonitrile, CjH(-CN, the methods of producing which were 
described in 296, 3, can also be produced similarly to the aliphatic 
Tiitrilps; fpr example, by the action of phosphorus pentoxide upon 
bcnzamide. It is a liquid with an odour resembling that of bitter 
almonds, and boils at 191°. It has all the propvties characteristio 
of the aliphatic nitrilea. 

Eomoli^iieB of Benzoic Acid. 

MB. The toluic acula, C,H, < pqoH' ""^ formed by the oxidation 
of the corresponding xylenes with dilute nitric acid. p-Toluic acid is 
one of the oxidation-products of the turpentine oils, which are first 

converted by oxidation into oymene, CHi^ ^CH(OHi)i. The tolulo 

acids only dissolve to a small extent in cold water, 

Fhenylao^ic acid, C.H.-CHi-COOH, is isomeric with them, and 
can be obtained by the method indicated in the folloning scheme: 

C.H»-CH,-C1 + KCN-*C.H.-CH,.CN->C.H..CH,COOH. 
Benirl ehloiida BeoKyl cr>nld« 

It is readily distinguished from the toluio acids by oxidation, which 
converts it into the monobatic benzoic acid, while the toluio acids 
yield the dibasic phthalio acids (380). 
/COOH 
ZylUs acidt, C,H,^CH, , have properties corresponding to those 
\CH, 
of beowlo aoid ; they, too, are only slightly soloble in cold water. 




ABOMATIC ALSEHTSES AlTD KEIONES. 



/; 



Aldehydes* 

TJ 

S99. BcmaldthyAt, C^Hi-C/?, is the best-known of tJie aromatic 

aldehydes. Lila» tj(^ aliphatic nhlohydra, it \r formwl by the osdda- 
tlon of the corresfHMulin}!: alcnhol, Ix^nzyt akohol, CflH,'CH,On, 
and by disfillalion of a, iiiixtiirn of a b<?iizoate and a formate. It 
is mani/fact unrd by lieatiiiR haiziti chlorUk, C'bHjCH • CI,, with water 
and caloiuin carb<.>tiat4^, a inctliud whose aliphatic analogue is of DO 
practical importance : 



C.H,-CH 



*-'= + H 



^'^- no 

OH "*" 



C,H,-cJ + 2Ha 



Ttie following mcltitNla arc otnplojod in tho prciiamUon of Its 
homologiies. 

1. Oliloro^jalic ester in rDowwI to react with an aromatic hydro- 
oarfaon iu presence o( aluminium oliloride, wlwn l-ho ester of aa 
a-kfltooic acid Ih proiliicccl : 

c,H, + cico— crxxi.ir, = nci + o,h,.co-cooc,h^ 

CI>l'0rO'O3>ilJi> ««ur 

The froo a«id ia obtained by flaponiftcalion, anil ou dry distillatioa 
]066S OOf, with formation nf the aldehyde : 

CHt-COOO,!! = CH,-oJ + CO,. 

S. An ftromn.l[(] tiyilmcarhnn is tn>nt(v(I with n. mixture of carbou 
nonoxide iinil*b.vdri>cbtvrit; acid in i>n.-»ciicc of nluoiininm cfalondo 
andatracsurciiproiuotibrido. It niiiyl)i!aMuinL<d that formyl chlor- 
ide, HOOOI, is obtaiDod tu nu intcrmcdiato product : 

CH,-CH, + ClOOH = HOI + Cn,.C,H,.c2. 

8. Anhydrous hydrooyaaic acid and liydrocliloric add are brongfat 

388 



AROMATIC ALDEHYDES. 



Z^9 



into contact nilli aromniic hydrocarbons, when fUdehydes are pro- 
<ln4ed, tUQ aidime boing fornifrd as &q iaiormodi&lo prodaot : 

cn, + cira + nci = c.h,-ch \rr.iici; 

Benialillini! Iijijruchlurhla 

tyij.oniNU.Hci +n,o = c.H^.c5 + nh,ci. 

Benxalrlehyclc is found in nature as a constituent of amygdalin, 
CapU,,N*0„ (242); on Ihie account, it ia called oil oj bUlcr almonds. 
It i:} a li()uid of agrccalile odour, is ^liglitly soluble; in water, boils 
at 179°, and has a specific prnvity 1-[)d(>1 at IS"* It has most of 
the propcrtips of the atiplmtic aldehydes : it is rpn<lily rtxidized, even 
by the oxygen of the atmnspliem («ijK>ciiLlIy when cijiosed tr) sun- 
light), reduces an anummiacal silver soliitinn with fDrmation of a 
nunor, >'iel*U a cr>'8tallirir additiou-pniduct with sodium hydrogen 
sulphite, a<l<l» on hydrocyanic at^id and hydrogen, forms on oxlitic 
and a phcnylhydmzonc, etc. 

There are, however, points in which it <lilTere from the fatty 
aldehydes. Tims, with ainninnia it dots not yield a compotiml like 
aldehyde-ammonia, but pniduci-s bijriTfAaiiamulr, (CftEI»CH)jN,, 
formed by tlie union of three incjlccules of bciizalili:Iiy(lc and two 
molecules of anuiionia: 

3CAC^ + 2n,N - CC,H.CH),N, + 3H,0. 



ITie behaviour of the aromatic aldehydes towanls alcoholic 
potash is characterifitic, one molecuieof the aldehyde being oxidized, 
and the otiier redueed {ef.. however, 117); thus, beuzaldehyde 
yields potassium benzoate and benzyl alcohol: 

2C,H.-c5 + KOH - C,H,-COOK + C,H,-CH,(>H. 

^H The aromatic aldehydes condense readily with dimethyUmlino 
^^ or phenols, forming dejivatives of tripheuylmetlmne : 



39° ORGANIC CHEMISTRY. 

It lias b«en obaerved that darinic llie (ucidation of TariotM sob- 
bIadcos ip the air, tt* niucti tayfcva is roadcrci) "nctirc "m it taken ap 
'by tha »iit»UiiCie uii(k-r oxiiliilioii (" luurgniiicl-litmiiiitr}-,^ SSI); thia 
ia true of benxalilohyilo. If il ia left for sevorn) weclta iu eooiact vitfa 
walpr. indlgoHiilplionlc acid, ami iiir, the juiind aiiKHiiit of oaygvn la 
nsvil np in oiidizini* ilio in<lif»<> demaliv^ as in eouverlin^ Iho bciizal* 
di-hyde inin beiiEolc add. Baktkr baa shown tbat bentoj*! hydrugen 
|H'Toxide, (',[|,CO-0-OII, U formed as an Intcnncdialo prodact, and 
oildises the iiidifcoxi'lrlionicaeid, bmnj; f tiwlf ivdaoedto bemnfo «cid: 

c,H,-cno + o, = o.Hi.co-o-on ; 

CJkOOO.Cm + Indigo = C.IT,.C00H -f Oxldlaed iniligD. 

Th< oxUIftlton of bciiialdebjrde In tlie air must iticnifora be ooraidand' 
to tttkeplaM ttiua: 

c.n.cno + o, = c,H,co.oon; 

QHrTO-OOH + CHjCHO = 8C.H»-000H. 

BlKTiB has, In fact, proved thai lionxayl liydro(ceii jMroxide dissolvoi 
when added to bcnz4ild«hj'dv, but Ihnt tbv liquid gmduaUx otwDgoa to • 
aoUd mass of pure benzoic acid. 

Zatones. 

300. Tho aromatic kfiones can be subdiviiitd into the mixed 
aronmtic-fatty kfUiii<«, ami ihe true aiY)riiatic kcrtom's, Thr best- 
known member of the first class is acetophcnonc, C^IfC'O-CH,; 
it OHii he nhtHJnptl by distilling a mixture af c-jUciiim aoplatc and 
bpniooto, or morp n-adily by the adtiitiiin of altiminiuin elilnndo to 
a niixtuTe i>f l>pnzene and ncptyl ehlnriile. It is a oryKtalline stib- 
stanixT of agreeable odour, melting at 20" and boilinj; at 200°; it is 
rflElitly Hobibli! ill water, ami po»<essca all the pn)|icrti€s of the 
alipliatic ketones. It itt (-mploycd as a aoporitic under the name 
" bypnone." 

Benznphcnonf , C,Hj-CO'C,H,, is a true aroniatic ketono, and 
can bp obtaineil by the dry distillation of calcium benxoate, or 
by the action of Ijmzene and alurainium chloride upon bciuoy 
clilnridr, or carbnnyl cliloride. This compound, although a Into 
aromatic derivative, behaves exactly like an alipliatic ketoue; 
on reduction, it yields 6CTwAyrfro/,CBll4-CHOH*CnH,; bcnspinocon*, 

<C,H,),0— -f CC^J,^ is amultancoualy formed (156). 
On OU 



/IROM/iTIC KETONES AND O'XIMES. 391 

Although the mechanism of Friedel and CBArTS' synthesis (868, 3) 
of the hoDDolognes of benzene has not been aatiafactorily explained, 
B0E8BEEN has put forward a complete explanation of the synthesis 
of aromatic ketones. Ho has proved that the acid chloride first unites 
with the aluminium chloride : 

CH.COCl + Aid. = C.H.COCI-AICI,. 

On addition of one molecule of benzene, one molecule of hydrochlorio 
acid is evolved, nith formation of a crystalline compound : 

CH.-OOCl-AlCl. + C.H, = C.H».C0-C.H.-A1CI, + HCI. 

On addition of water, a quantitative yield of the ketone is obtained : 

C«H.-C0-C.H,.A1C1, + «H.O =C.H,CO.C.H. + AlCl..nH,0. 

The reaction therefore takes place in three stages. 

Benzophenone exists in two modifications; one of these is un- 
stable and melts at 27°, and the other is stable and melts at 49°. 
The difference between these two is a purely physical one, since 
different derivatives of them are unknown. 

Ozimea. 

301. Investigation has shown that some of the oximes of the 
aromatic aldehydes and ketones exhibit a peculiar kind of isomerism. 
Thus, there are two isomers of benzaldoxime, hemBji^aldoxime, a 
liquid boiling without decomposition, and bemsynaldoxiTiie, which 
is solid, and on treatment with acetic anhydride readily loses water, 
f onning benzonitrile : 

C^jCIH 

III = C,H.-C=N + H,0. 
N|OH 

The onfialdoxime yields an acetyl-derivative with acetic anhy- 
dride. 

It has been proved that no isomers of the ketoximes p,>C;NOH 

exist, when R and R' are similar ; two isomers are known when 
these groups are dissimilar. Benzophenone oxime and its derivatives 
furnish examples of this. In spite of many attempts to prepare 



39" 



ORGANIC CHEMISTRY. 



an isomer, benjophenone oxime-ia only known in ooe modiBcatioix. 
When, howeve-T, hydrogen in one plienyl-gmup 13 substituted, two 
isomeric oximes can be obtained. Monnchtnrobenzophenone, 
C,H» ■ CO • C,H,Cl, monobrtJmdbt-nzophcnone, C^H. ■ CO • C^n.Hr, 
ttjlylphcny Iket^Mic, CH» "C.H, ■ CO ' C^Hj, anw>-lphcnyIketone, 
CH,U-CaH,'CC)'Ci|1Is, anil many utbcrs, arc examples of ketones'] 
which yield two isomeric oxinics. 

After several ineffcetual attempts in explain such isomerism 
by the ordinarj* stnietural fornuila-, the following stcrcochemieat 
explanation of the obsened ^acls lias been Mlopted. It is assumed 
that the three nffinitips of the N-atom are directed towards the 
angtes of a tetruJicdron, the nitrogen atom itaolf b4^iig situated at 
the fourth angle: 




Wlien the three nitTogen bonds are linked to carboQ, as in the 
nitriles, the following spscial representation is obtained: 




Stereoisomcriisin is here impoasible: expcrienoe has shown that none 
of the nunierous nitriles katnm ocoun in two fonns due to isomerism 
in thcCN-groupp. 

A^Tien, however, the nilmgrn atom is linked to carimn by two 
bonds, two isomeric forms become possible: 





STBREOISOMEMSM OF THE AROMMTfC OXIMES. 
l&eMean be mun> readily repn-senlcd by 



393 



X-O-Y 



X— C— Y 



li-z •"- z-11 



I', will be ob8or\TH Ihat different oonliguntioiifl for siich eompoiinda 
are ntily obtainwl wliwi X and Y are dItTerent, since, when they are 
nmilar, the figures beoome identical. Tliis agrct'^i witlri the fauti 
etateJ above. 

It CAU Also be del«rmhii»l which confiftiiration belongs to each 
isomer, lliu iwu tsoaierlc twuMltloxiiues li&va ttia roriuuiiu 



CH.— 0-H 

II 
N-OII 

Bcnw^naldutUao 

L 



and 



cii,— c— n 

I! 
IIO-N 
Benua n n ftldoslma 
U. 



In tonnula I, H find OH aro nwimr togntlier tlmn in ronntiU IT, 
irhioh explains the roni]iocu nnlh which oii« tuolcculo of irnter ia 
«plit oft rrom one nidaxime (<yw). ^n*! ■"»' trom the otiior (anti). On 
thl^ nccouiit uouliitu ruCion I is lussigued to tho «^(taldoxime, and coo- 
con fisuraliou n to tliotiJif/rilJoiiinc, 

Tho conflgiiralion of the Itotoiiinoa can be dotermincd by (h« 
BeckuaMK trituHforrantioii ill2», hA U mndc clear \n tltu fullovriag 
eiauiplo. Tvo Isomera of nQisylphenylketoxinifi arQ known, 



CU.O-C.H»-C— C.H, 

II 
2(-0H 



and 



CH,OCH,— 0— CiD, 

HO-A • 



IL 



the Bnt melting at. 137' and tho socood at US'. Bf the Bickmakk 
tranaforiDHtion, tho oximo of Uiglicr tnnltiug-|infnl j'kililit tho ]tniUd« 
of aiiiitic aoid ; that of lower mcUiiig- point, the nttisiJo of bonsotc 
H«>d. Tbe former muHt th^reforo tiavB cootlguniiioii X. and (be 
Becoud coiiflKumtioti II, bocauiio io I th« groups OU and 0,11^ ar« 
o«it to «acb other, and exchange plBces, 



CH.OC,H.-C-On 

II 



CH,0 0,H,— C=0 

SU-O.H,' 



394 ORGANIC CHEMISTRY. 

prodocing the anilide of aniBio acid, CH,O-0aH«-CO0H ; vrhile in 
II, anisyl (OH,0-C,Ut— ) and OH are next one another, and exchange 
plaoee, yielding the aniside of benzole aoid : 

HO— C— 0,H, 0-0-OA 

il . -* I - 

O^O.OA~N CH.O-C.H.-NH 



SIAZOCOHPOUNDS ANB HYDRAZINES. 



I. siAzo coMrounDs. 

Thp (liazo-oonipounils rjf the aroiiiatic scri€«, dwcnvopod by 
Cbjess ill 1S80, are not merely o! tlieiirelical irupuruiiicc. but play 
an important part in the maoufacture of dyes. In the fatty series 
only Qmino-coinpouiids of a special kind arc capable of yielding 
fliaKu-com[K3UiicliJ (201), while their funiiutiuQ is a general reaction 
of the primary aromatic atniiios; the propertif o} undrrgoitig dituo- 
li'tuti'on IS diaracttrixlk of aroiruilk amines. 

Diazo-comixiunds are substances containing tbe Jicroup — N, — . 

jTIicj' are divided into two claHscs: the dinzonium compounds, with 
properties analogous t^ ammonium compounds, from which their 
name is derived; and the true diazo-eoiii]jouinIs, in which the group 

[ — N, — ha* tht- w)iiKlitutiou — N = N — . 

The diazonium compounds ihemselves arc of slight importance, 

' «jid are usually not isolated. The numerous traiutformtitioiis which 
they can undergo, however, with fomialion of a great number of 
derivatives, account for the great importance of these substancee 

(in the chemistry of the aromatic comijounds. 
Diazonium eonipoundK art- fomiwJ by the action of nitrous add 
«D tJie salts of aromatic amines: 



C,H».NH,-HNO, + HNO, = 2H,0 + C,H».N,.NO,. 

Atilllno niiritt* n<>nuiDaillkionliiin nlirat* 



V 



TUs is usually carried out by adding a solution of sodium nitrit* 
to one onntaining nn ecjuimolecular pmpnrtion of iJie amino-.'^Ut 
and an equivalent quantity of a free mineral acid, the reaction- 
mixturc Ix-ing c(H>led by the addition of ice, ua the dinzomum 
cnmpraunds decompose very readily; a solution uf the bennenc- 
diazonium salt is thua obtained. In order ^to isolati! eurh a KtUt 
u)>efuctuduizfm\umehlf^de, CaH,-N,-C'l, in the nolid state, a small 
uantity of concentrated hydrochloric acid is added to an alcoholic 
eolullon of aniline hydrochloride, and then amyl nitrite, whereupon 

39i 



396 



ORGANIC CHEMISTRY. 



the dlazonluni cKloiide ci>-staUizcs out. The r]r>- duuonium salts 
are exceaaively explosive, and must tht-rrfon- he handlttl with grrat 
core; tJiey arc quite hai'inlc^ in aqueoim ttalutioD, and an it iit tin- 
neowwarj* t^ isolate them in order to employ them in reactions, 
they are seldom pneparwl in the soliii state. 

The group X.X of the diaroniiim compounds, of whieh X is an 
acid-refiidue, is only linked to one carbon atom of the benzene* 
nurlcuH, for all their transform ati<iii.s produce svdwtances contmning 
a group likewise linked to only one carbon atom of ihe nucleus. 

The constitution of the diaBOiiiuni-group, ^-NjX, can be de- 
ilueed from the following considerations. In many respects the 
group CbIIj'N) — bohaves similarly to an alkali-metal, and srill 
more to the ammonium radicle. With strong mineral acids it 
forms colourless fiahs of ofviitral reaction, like KCl and Nir,Cl, 
while itji Halts with carlmnic arid rraemhic? the alkuti-earbonstcs in 
haviii£ an alkaline reaction, due to hydrolytic dis3H>ciation. The 
conductivity of the diazonium mXln of hydrochloric and other acids 
sliou'8 that they arc a^ strongly ionixed as KCl and XH^CI. Simi- 
larly, diazonium chlorides yield platinum double salts, such as 
(C,HiN,Cl)jPtCI,. which diswlvc with rliflicnlty in water. Otber 
double salts, such as (C^HjNjC'UAuCl,. have also been obtained. 
Free bfrnentdiatonium hjAroxuic, C,H»-X,-OH, ia only known in 
ai|uem])i ."lohilion, which has a strongly alkaline reaction. It is 
obtained by In'stirigthe a^iueoua solution of the chloride with silver 
oxide, or by the a<!dition of the wiuivalent quantity of barj'ta-watrr 
^o the sulphate. It is cdloiirlcss, like causlic-imtash solution, but 
thi-ouch dcconipusitiou gradually deposits a flocculent, resin-like 
substance. 

The existence of a pentavalont N-ntnm in the diazoniiim salts, 
just as in those of amnumiiim, mii-st thcn-fon! be a»«uniL-d, the basic 
properties of each being due to its presence. Two formube are 
therefore posMble : 

C,H,N=NX or CA>r^N- 
As will be proved in 303, the preference must be given to the second. 



Beaetions of the Diftzonium CompouDdi. 

303. Many of the reactions of the diazonium compounds aie 
characterized by the elimination of the group — N, — as free nitrogen 



REACTIONS OF THE DIAZONIUM COMPOUNDS. 397 

from the molecule, and its replacement by a substituting-group 
linked by a single bond to the benzene-nucleus. Extended re- 
search has revealed the best conditions for obtaining nearly quanti- 
tative results in most of these reactions. 

1. Refilacemerd of the Nj-group by kydroxyl. — ^This is effected by 
allowing the aqueous solution of the diazonium salt to stand, or by 
warming it: 

C,Hs-N,-Cl + HOH = C,H(-OH + N, + HQ. 

2. ReptacemerU by an alkoxyl-group, — ■ CnHjn^,. — This is car- 
ried out by boiling a diazonium salt with alcohol ; 



C^-N,- |HS0, + H1 0-C,H, = C^O.C,H, + N, + H^,. 

3. Replaeement of the diazonium-group by hydrogen. — Under cer- 
tain conditions the diazonium salts do not yield alkoxyl-com- 
pounds with alcohols, but produce the corresponding hydrogen 
compound, the alcohol being converted into aldehyde : 

NO, C,H^-N,-a + CjHsOH = NO^.C.Hs + N, + HQ + CH,0. 

p>Nitn>beDzaaedlubiiluin NiimtwnMuo AceUldehrds 

chloiids 



By this treatment, p-diazobenzenesulphonic acid, 



when treated with methyl alcohol under dimiaished pressare, jlelda 

only beozenesnlphonic acid, the diazonium-group being therefore only 

replaced by hydrogen. Under a pressure of 30 atmospheres, however, 

flO H" 
only anisolssalpbonic acid, CaHj<Qj,Jj , is formed, N, being replaced 

by the methoiyl-gronp, — OCH,. 

4. RepUtcemerU of the diazonium group by halogens. — ^This is 
effected by treatment of a solution of diazonium chloride either 
with cuprous chloride dissolved in concentrated hydrochloric acid 
(SANDMBTia), or with finely-divided copper (Gatterwann) ; 

C,^-N,-CI - C,H,-C1 -I- N9. 



398 ORGANIC CHEMISTRY. 

Cuprous chloride, nod dnetf-dividM] copper, bave hcra a catalptHs 
KCtion ; it ifl jirobaUo thnt n coptier vompouiiil is rormed m an iotor- 
m«dtH(« jtroduct, aiid m ».ttt:rva.riU AtictimimiuHi. 

Itcplacumviil \)j bnniiiin: m cnrrk-d out- in the same way: thus, in 
the preparation of brotuobuuzGiie, a soltitioii of polassJum bmrntilu is 
lukkd Id ail viiiiifOLis itiiliitii>u tit twiiwiiudiaxDiiiiim aiilpliaxi con(»iiiing 
froe siilplitit'ic nrriit ; i>n nddiiioii of i!n)i[N;r-diui to tiiU mizturo, 
iiilroguii ificvolvcil, atHi brnTnnhoiiBBtic is lormwl, 

KeplacenierU by iodine takes pinw ivnrlily when a warm Boluiion 
of polawiuin iodido Li add^d tu a diaKDUluui tiuIpliateaolutivD ; it n 
unoftCMSsiirjr to employ copper or cuprous ctiloride. 

5. Replacctnenf 0/ Oie dioioniwn group by the Cti-ifroup. — This, 
too. readily takes i*iaoc in presence of copper compounds. T'te 
solution of the (liazanium salt is uliled Ixi oni.' of potassium cupraus 
cyaiiiJe: 

C,H,.N,.Cl + KCN = C.BI,.Crf + N, + KSI. 



Thi« rc&rtion is »f gmat. tmportuiicr for the 8>'nth«>iB of aromatic 
[■acids, which can be got by hyrlroIyzinR the nitrilw thus obtained. 

6. Olfier rwctifjiu van bo carriiMl ont l^y Ircnliiig dtaiMiiinoi aalls 
with siilpljiircttitd livdr(i|'L<i). tvliloh ywWs C'litiiiuiinds i>iiit;iiiiiDF; 
sulpiiuc linked lu tht; bcitzciic-iiuclDiia. Uy llii& trmlmctit, b(!i>r,<>iie* 
dinzoniiim ctdoride jiolds phenyl sulphide, K-gll^iS, two molcoii1«s of 
tiiu cliluride reiiclliig n'illi <mio of HiiliMiiirullcd )iy<lrof:cn. 

Tli4> Ni-tii'r>np onii tiUo bn r«pliiri!d by uroiDiiiio liydrocitrbon- 
rcsidues ; thus, ttipficnf/l, C«II,-Oo1l,, is oblaintMl by Irv.-iling dry bfna- 
etiediaxotii urn ctdoridf with btiiiz^'iie iu preaanoa of a small iitiantitfof 
aluuiiiiium ciilurida : 

CHj-N.-oi + H-cn, = c,ir,.c,iTt + N, + hi:l 

Tlioso reactinno illustrate the ini|>firt&nce of the dtazonium salts 
as int4?niifdiale products in the pn-pni-aliim of iuiin<Ti«i»siih.stanres. 
Since rhey arr ilcrivrd fniin the utnincs, which an- prri«in-(i by the 
reduction of nitro-^om pounds, it i^ evident that tJic nilTalinn of 
aromatic derivatives is a r<-8ction of great iniportjiice, for the nitro- 
group can he rc|)laped at will by almost all ot iter t'lements or groups 
l^ meanaof the amiuo-twm pounds and diazonium corapoutida. 

Haktzsch baa eiplsitied the reactions of the diazoiiium ouiti|H>unds 
by tuBumiug that tliey lbe[aa«lv«B do not eutt-r into rcuctiou, biit are 



REACTIONS OF THE DIAZONIUM COMPOUNDS. 399 

first converted iato a Ayndiazo-oompouiid, which then decomposes 
with evolution of nitrogen. The formation of phenol must then bs 
T^resented thus : 

CA OH C,n» OH C,H,OH 

( [ I _, Phenol 

NBlf + = HOI + N=N NbN; 

I «tntDUio- 

Cl H IvdroUdA 

DUtODtum 
olilorlda 



and that of chlorobenzene thus : 

0,Hi CI C,Hj CI C,H,CI 

ibi 



J I I I —4 ChlorobeaMna 

N=N + = N=:N 



I I nnDlOio- 



H chlorlds 

The reactions between diazonium salts and alcohol are explained 
■aa follows : 

C,H, 00,H, /C.H, OC,HA C.H,-OC.H, [ra^Jtonof. 



NbN+ I 
CI H 



/C,Hs OC,HA C,H,-OC.Hb 

V N=N / ~* N=N 
CI-H Cl-H 



C,H( H CjHj — H [FomiMIon of » hydrocarbon]. 

NhN + I -* NsN 

CI CiHjO CIOC,H( [Splitting up Into HCl and aldahyde, C,H,OJ, 

As these transformations of diazonium salts cannot be explained 
bfi the other possible structural formula, Cgllg-N .^ N>X, it is evident 
that it must be rejected (802). 

Moat of the syndiazo-corapounds are very unstable, however; they 
change readily into anfidiazo-compouiids, in which it is assumed that 
the phenyl-group and acid-residue are far removed from one another, 
and can therefore no longer unite: 

C,H. X *?«^' 

N=N 



u 



(jmlXazo-com pound; antfDlaio-com pound: 

C«tli Kiid X can unite C|Hi and X cannot UDita 

with one anolher with one another 

In oertain cases, such as that of the diazocyanides, Hantzsch baa 
been able to isolate these intermediate products, and thus afford a 



400 



ORGANIC CHEMISTRY. 



proof of tbesa riows. For «x«ropl«. wlisn cyanidfs arencldecl lo diazo- 
tizedp-cliloroitnilinc, Cl-CaU,-Ml,. p-chlorobcnzoDitrile, 01-C(tI,-CK, 
is not, inimcdJHiely fortnvd; it is possible to isolate a yellow inierm^- 
di»l« |jroducl, ClO^IIi-Ni-CN, wbicb yk-lds j»-<)lilorobeDJoiiilrileafler 
«iJditi«ii ot co[j|H-r-Uuii[, i)ie ncUon being accoinpunied by mi energelio 
OToluIiou lii iiicrofjcn. This y«11oiv iiituriocdiato j?>GliloroboDz«De- 
jyfiiliazocyriulde i». )iuw«vei, vury uiiBtabI«. anO sp«(<di)jr changrs lo 
Ml isODtcr ([b« <iii^'-com]K)ui)dj which does not react with copper- 
dost. The fitcronclieniicRl llieory thus Affords a satisfactory explsoa- 
Uon of tbu obii^Tvvtl [>bpiiuotena. 

It mi|:)itU-Kii)U!tntlfd tbaLtb« iin»iablt! primary prodrjtlsitiaKoninaL 

ejAnidc, i . This cannot be tbe caw, for &acti n CTanldc' 

N 
toast ha?* proiwni^-s niiHlogons to those ot potassLum cyanldtt, it must 
be colourless, liko tlio oHit-r dlAzonium uUt«, have an alkolloo reaction 
in aqueous solution, anil conduct tbe electric current, wbereiu tlio 
aaslabit! pnmnry product possotwcx none of iheM properties. 

Mnrt'ovcr, rni uuiaolc cIcriTativc, CniO.O.U,NcON, was diacoTcrod 
'by lU-VTZscB, nliich toust be looked upon as a diflE'iniiim cyanide, 
oincu itA »i|ui-aii.<) Aoliition does poaaesa all these propenioR. 

Bcnn>nitdi.-ucuniuin hydroxide ia a BlroD;;bn.<te, bm n<Acls villi allcalia 
h) i\ manner tiuilti iitikiinwii nnioii)j: the slroDic mineml bn»(«. Wliea 
a (11a.taniiim «iilt in i\iUlv*\ lo a atron); .viUiiion of cauitUc potaitli, 
a pota&sium derivative. (',II.-S.-OK. sc[wraic» out. Tlic rvaclioo 
talcc-8 placf) not only in conceiilrattd but also in dilute solutiotts. 
Wlxni ti ilihilo fioluliciii nf bi?iii'.fitedi»Koniuin liydroxido in tn-aird wiib 
an 4>quiTn]0ul quantity of caustic scidn in diliitt' soluiioo, tlie molcctilnr 
condiictdrlty of llie mixtum iscunsidvrably 1rs« llinn llii; sum of ihe 
twoeloclrie oontluetlvlijcs of the solulioiiM sci>«rati'ly : ii rollovathata 
porlioti of ttie ions (ClIiNuO/ + II' and Na' + OH', wliicli have bnm 
brouglit into oontaut, bavu fbangnd to tbe nou-imiizeil &tato— anion of 
H' and Oil' — that ta, tlio formation of a sail niufil bavc occnrrod. 

ThtiH, the d)ii7.oninni bydroxido, which is n alrnit;; Iwso, op]>ean to 
behnvu liko ku acid also. Siooo this ia very improbublfl, IlAiO'MiTB aa- 
SQincs that an «<c|utlil>rium oxista in tliu a^utxius solution iMrtwwQ tb« 
diazoniuio hydroxide and tbo syndiazoliydroxide (p. 8S9}: 



C.H»N-On _ C,H»N 



N 
Dlaxunlitm 



HON 

lijdraiUl* 



Beiapposes tbat tbo alkali dcrivatiTea araderiTed from tbe latter 
QOtBpound. 



DIj^ZO-COMPOUNDS. 



401 



804. The importftnce of the diazoniiim compounrts is not con- 
fired to reactions in which the nitrogen atoms are eliminated, idtioe 
important tlprivativ«t. in which tliey are retained, are known, 

1. Dinzoam\itn~rom'pnun/is are olitaiiieil by the actiiia of primary 
and secondary amines upon clifuioniuin ealta: 



CA-?frlCl_+H,NHC^, = C.fr,N,-NHC„II, + Ha 

DbumimlnoboDswie 

They aro also obtained when nitrous acid reacts trith Tree aniline 
instead of an aniline salt. It may he siijiposrH that in this reaction 
benzcnediazoniiini hydroxi<ie, or rather benzrnediazohydmxide, is 
first formed, and ta at once attackcifl by a molecule uf thu aniline still 
present; 



1. C,Ha-NH, + UNO, = C^Hi-Xj-OH + H,0. 



II. C,Hs'N,-; oH + H NHC,tf, « C^,-.V:N-NHC,H, + H,0. 



BftD.n[)c<liaiol>7iIri ziila 



Tile diazoamino-rompoimda are crystalline and have a yellow 
colour: they do not unite witli acitU. In aeid hoIuiIou, they are 
converted by treatment with nitrous acid into diazuniuni salts : 

C^*N:N*XHC,H,+ HN0j + 2Ha = 2C«UjN, + 211,0. 

The most characteristic property of the diazoainino-nimpounds 
b their rratly tran»fnnimtion iiilo isomers, the rtmirtaata-rem'poundt: 



DlAtOOJllIoobFIIMDr 



A ni ICUM«Oh*D*HI« 



Tliia ia best carried out by adding aniline hj'dmchloride to a solu- 
tion of diazoaminobeiiiene iu aniline, and warming the luixlure OD 
the water-bath. 

The aniido-group in aminoaaf^xmene is in the para-pusition to 
the azo-group. When the para-poGiCton is alreafly occupii-d, tbe 
amido-group tokcs up the or(/(f>- position. Aminoanobenzene and 
many of its derivatives are dyes (320). 



401 



ORGANIC CHEMISTRY. 



The ftbove equxtion iadicAlas tliat tliA iraii'ifoniialton of diazo- 
aiDinoheTiz(<n« into fttninoaKibeiizene is ft unimoSeculftr reaction (*' In- 
organic Cbemintry." 50). Ooldsc-iimjdt provc<l by MptTitntrit thtit 
this riow H curruol. Il« <liti9nlv«d diiizixtiatiioWrixi'iie in aniline, And 
fleii>rmiii<!d iho quARiity of diasnaminobenscnQ Htill prcaeDL after t-ho 
lapsQ of Icn4)wn periods of time. 

Tlie aiiilint! liydmcliloride iianally &ili)i>(l in i?jirryiiig out tills expeH* 
ment \\n» iiMirrly nt-ntAlylic itccptfrntlii^rlTrct upon liio rvactiort; Ibis 
is pi'ovcil by lliu UQiform kEicrooiso in itio volucily ranslatit vriib Id* 
CKtific in llio amuuiil of nnilino hydrochlondo, mid in oth&r ways. 

It lias also been sbown tliat when different nails of aniline are 
employed, their catalytic inflaonco vnries in nmaiint, and is almost 
proiwrlional lo their detcree of innimtion-ln aqneous eoliitlon. This 
vriut provoil )>y Goi.DRCHHinT for the aalllne salts of dtolilopoacotic and 
tTicliloruno.-tic ut-ids. 

TliU pliKUouiuiiou twn be ccpl&iued by tho nfisuniptiou that aniline 
salts are decomimsed into free nc^id nnd nailliio wlieii di&solTcd ia 
aniline, in a manner Himilar to tho BeliiTif;-frea of miUa fruui their 
nAti;r orcrystblliiHtticin wlicn di»aolvi^ In wiitui- aiii] by I he further 
aHMiiiiiiiinn lliat (lie Gl;glit ionization niiderguno by Ww fn-o iickd la 
thomiilinu — such solutions being vt-ry poor conductors of tbv cloclrio 
curmul — is jjruporLioual to tli0 di-gruu uf jouixatioo in iiquiwus so- 
lutioo. 



2. Diazonium ttalts unite wit!i tertiary smioeH at the para-po^ 
tion: 






3. They react similarly n-ith phenols, furniing hffdroxyaso-cma- 
poumta. This lakes placo ia presence of alkalis: 



C.H,-i\,-i Cl + H JC^.OH 
rbMioi 



C,n*->-':N-C«H,OH + HCl. 

UjdrcixymKibeajEs ih 



A nurn>)or of important dyes are also derived from fit/droxy^] 
azobmsaie (322). 



n. HTDBAZIRES. 



805. TTic most important derivative of liydrazine is phenyU 
hydrazirip, Cnllj-.MPNH,. whinVi bas Wen refurrwl to several times 
in the fatty 5«rJes in connectjoa with its action ou alduhyilea, 



PHENYUIYDRAZINE. 



403 



ketones, and sugars (11 2, 208, ami 212.) It U formed by the reduc- 
tion of thi- dlazotiiunt salts; for example, from betut«nediasomum 
chloride by tlic at-tion of the calculated quantity of etannous chlo- 
ride dissolved in hyitroehlorie at;id; 

C,Hi*Ni'a -I- -IH - C,H,-NH— N*H,-HCI, 

It can also be formed by transfonuhig the diaKoniuni salt intn a 
diaxosiilphonal* b_v means of alkali-suipliilH, reducing the dia;tmiil- 
phonatc nith xinc-tlust and ac<*lic' acid, and splittiug i>ff the sulpiiu- 
group by boiling with hydrochloric acid: 

I. C,Hj-N,-C! + NarSO, = C,H,-X:N-.SOj.\a -1- Naa 

Bndluiri cllaiobvnK^MHllplienllU 

n. CA'N:N-SOj^a -f 2H = C„H;-XM-XH-SO,ya. 

Sodliiiii I>h^nylbTlJnkIlamlipboIla■« 



nr. Coir,'NH-NH-SO^a+H,0 



C.IIsNlINmj-f-XaHSO.. 

Ptit-i)fliiydr«iliM 



k 




Thie apparently roundabout way in Bimplc in practice, since the 
intormciiiatJ? proibmts (lt> not, no«l to be iKolatnl. It i,s suflidoni lr» 
mix tlir .solution of the diaxonlitni salt with that of t\\v f.\\\\t]nW, 
then to add the acclir arid and j;inr-<lu«t, and filfor off tJie excess 
of the latter, Thr iiltrnte is then bi)il(<l with fuming hydrochlnric 
acid, whcr(!ii[M>n the hydrochlorid**, (.-gi^li'.MI'.Mlj'iK'l. sfparatcs 
out, since it i« soluble x«th diflieulty in water, and almost itisoluble 
iti hydroehloric acid. 

Phenylhydraitine is a colourless, oily liquid, tnndng brown in 
the air. Its melting-point is I7'5*, and its boiling-point 241°; 
when boiled under onliiian- prc«anre, it imdcrgCM-s tiligbt decompoai- 
tion. It is only slishtly soluble in water. 

I'henylhydrazine is split up by ^nerRPtic reduction into aniline 
and ammonia. It is ven." wnsitive townnis oxidixiuji agenls, its 
sulphate iKinp oxidixed tn the dliizoniuin siilt by niiTcury oxidp. 
Oxidation usually gora further, however, the nitrogen being elimi- 
nated from the molecule. I'or fxamplc, an alkaline copper solu- 
tion converts it into water, nitrogen, a.n<\ benzene. Fhcuylhydra- 
zinc has n wholly ba.sic character; it yidds well-defineil crj-stallino 



404 ORGANIC CHEMISTRY. 

Phenylhydrazine is proved as follows to have the constitutional 
formula CaHj'NH'NHj. A secondary amine is converted by 
nitrous acid into the corresponding nitrosamine: 

C^-N<Hj,-C,H.N<NO. 

HonometbfUnillDe NltraaometbjIaDUlne 

On careful reduction, this substance yields melhylphenylhydreusme, 
CBH(N*<pjr', which can also be obtained from phenylhydrazine 

by the action of sodium, one hydrogen atom being replaced by the 
metal. On treatment of this sodium compound with methyl iodide, 
the same methylphenylhydrazine is formed: 

C,H,NHNH, -. C,H,N<2^ -^ CJI,N<^. 




COUPOUNDS COVTAXKINa A5 UNSATUKATKD SISE-CHAIS. 



Hydrocarbona. 

WW. Stiirolf, C,n,-CH:CH^ which derites its nrnno from its 
occurrence in storai, c«n be obtained hf tieiiuiig oliinamic acid. 
C,IIj-0n:CH.C0Oir, which spins off CO,. it is n. liquid of ftsrce- 
al))e cidoiir. nnd lioils al UR', It is mm <TleiI nii lieatjiig. and also 
slowly oil siniidin^ «t ordiiiJiry i»'inpi.>rnl Hres, intra a ^lasa like mn»a 
called met asly role, » polymer of niiktiown innleciilnr weight. Sljrole 
bns ilie power, chiimcUTiBlie of siibsluni;«'a oontAiiiin; A double bond, 
of formlti? ftddiiion-iirodiicls. On treRrmeiit with iiliric nciil, it. 
jiifHt nitrastyrote. C,II(('iI:Cn-NO„ with llift nlrogtonp in (bo 
fttdu'Clmin. Tho i-unntiintinti ot iMh omiMxind follows rrom ita fortna* 
tioa by the condt-n^tinn "f brnz.ildchydo with nitrometbaue, under 
tbe cMalyiic influence of lUcobolic potnsh : 

C«^'-*-"|b"TTl.iCH.NO, = C.»*Cn:C'K.NO. + H.O. 

Phmylaettl/ime. C^IT, C *, CR, can be obtaine<1 by trpaUng teoto- 
pbmionc wilii idiosphnnis pentncblarido, and nrtinicoii lliu rctmltipg 
oompoiiTKl. (_',H, COIj-CH,. with oau»tjcpoi»sh: or frwni jihmijlpropi • 
olic ficid, C|(lj C ;C-C00n. by nlow diitlllnlioii with Anitiiio. In 
roitny rcspectiS it rDsembiM nceiylcnu, ylcMing mctnllic derivatires, for 
exampie. On solution in coiiccntrntcd sulpburio acid, it titkoa np one 
mol«cLle of w&ter. (nrming aci-topheiiona. 



AUoholi B.nd Aldebydet. 

807 Cinnnmie alcohol, C'^H, cn :CHCH/>H, \% the only repr». 
aentotiveof liii:*o alcohoU which need he iiienlloned here. It is n 
crysIalliTio Buhsranec wiiU nn odour of hyacinih*. nnd 1« pmirnt m An 
estCT ill slornn. ('artful oxidnlion conv^rU it iatocinnamic acid, nod 
mors vigorouit oxidaiion inta benxolo noid. 

S06, CinnamaUlthydt. CJI^ Cn:CHCg, ii)thechi«r cODeliiu^nt 

of oil of cinnamon, from which it can bo obtained by uieani of 



4o6 ORGANIC CHEMISTRY. 



• 



tt« au1pbit4 compound. It is an oil of aKre«abIe odour, and twils at 
246*. Ic is re<titiifl«l by ilmng aoidn, nnd <rielila a oompound 
^]((-«II)^U|)i <''^l) aimnonia, iu tho s4imu wiiy u Wasaldefajde (9W>. 

Acids. 



309. Of these, n«na»JiVaftW,C,Hs-CH:CH -coon, is the most 
iinporliuU. \t\s |)ri-s('iit in sniiipl]at»Lms,and instorax. It is manu- 
fac'Liirud by a. synthetic melhml (liseovt-reel by W*. H. I'ebkis, Sen. 

BeiiialdeliyJc is hcatwl with acetic auhydridc, in presence of 
sotliuni acetate us a catalytic ogiMit : 

C,H,cJJ+HjCHCO O CO CH,'*C,H,CII:CH0O'OCOCH,+ 

HeuxaUebjril'i Awlli- nuhj-driila 

+ H,0 - C,Ht-CH:CH0OOH + HO-CX)-CH,. 

Chitwnilc Kill AcmJc Mdd 

Perkin's synthesis can be carrietl mit wilS aubetitutcU bcnz- 
aldehytlcn on the one hand, and with homologues of acetic acid or 
with dibasic acids on iht- otIuT, so that it in piwsible to obtain a 
great number of uusaturaicd aromatic acids by its ait). 

OinnniDic ncid cAn aIso boobtmiicil by the nction of bvtixnl cUlnriilo 
^Sllj, CjlIj.CllCI,. [i|«)ii sudiiim ncvlule. It ciiii furlUor bo syoibo- 
iicod bj' l)i(d con<]t:<ti6ittion of makinic &cid uilti beiixuldohyde, wbtcli 
takes placB KEdiljr uiiditr tho catHlylio icBnoaco of ammoQiit. ou« 
molecule of carbon dioxido bciDg splil off: 



llklaiileacM 



rCSnnamic acid ia a rrA-xtalllne substance, melts at 131*, and di*- 
aolvea ivith dillifully in wltl water. In all respccte it posSKSftes thn 
character of u substance with a double bond, and thci^ore foniis 
a<Idition-productJt and reduces Baeyer^ reagent (188). Its con- 
stitution indirates tliat twu slcivuisoiners are pussible: 



C,Ha-C-H 

H-C-COOH 



and 



C,1L— C-H 

cooH-0— n 



An isomer, oHocinRamic acid, is known; it is readily transformed 
into unltnary ciniiauiic ucid. 




POLY-SUBSTITUTED DERIVATIVES COHTAINIirG 
SIMILAR SITBSTITTTEHTS. 



310. Tlie number of poly-siibslitiitrd dprivativca of benzene 
and ils honiologiH-s Is vpry grrnt. The hydrogen atoms of these 
hydmcarbons ran be rc-plarnd nnt only by two or more amilar 
groupfl, but also by two or more ilifforrnt gn>iips. For rach liiwib- 
st it ution- product and for each irUubstitut ion-prod uet of beii^en* 
three isninors arc possible when the siibstitucntu ar* similar. In 
the homologues of benzene, substitution can take plaw wholly or 
partly in the siiie-cihain ; thus, the following isomers arc theoreti- 
cally possible for a com;iH>imd C,LI/^I,: 



^^ cai 

(5) 



a/~~\cii, ci/~^H, 
ci ci 

(2) C3) 



ca 



(4) 



CI 



a 




H, 



CJ (^ 



(6) 



(7) 



^ 



tS) 



(9) (10) 



A large proportion of the niimerous compounds thoorelically 
possible is kno*-n. Only a few of the chief of them ran be consid- 
ered here. 

It would be impossible to lic^crilx! for carh of these compounds 
how thepoffltions of ils subetiluciit^ {oriental ioji) has bwn deter- 
mined, so lliot a summary ttill be given of the methods of orien- 
tation in 352 to 3fi6. 

40J 



4o8 



ORGASIC CHEMISTRY. 



I. rOLTSUirKORIC ACIDS. 

Stl. When b«DE«ne and iia hvmuloKues are treftt«d vith fuming 

lUlpfaDrie will, duul^ihonio »nil iruulfilioitit: xcide. twj similMr in 

prop«rtie« to the Biono^utphonic &eiA», nrt fortued. Cntler thU ircat- 

nwnt, b«uieii« yields m^flUttipfio/iK acUl, whicb. on prolougMl liraliog 

9 partlnUy convertod into tho jHtutiiphonic aeid. 



II. POLYHALOOEH DBBIT&TITXS. 

312. ThpBp can Ije nbtainpii by the dirpct actinn of ohiorine or 
Ijroniinc iipim tin- nninialir hydmrflrhons. If one lialoKcn atnni is 
already prrsrnl, 5iiI)ntLtiiti[>ii takrs place principally in the p-posi- 
tion, a smaU quantity of the fl-cnmpound being also formed. m-Di- 
chiortihemtnt or m~<iibromr^(nzent is obtained from »^d^nitPoben,- 
stcnp (318) hy reducing to dinmine and subscciupiilly diazotizing, 
3l has bifen found possible by prnlnnRwl halogenalion to replace the 
rix hydrogen atnms of henzpne by halogen, C,CI, (JuLixs' chloro- 
■cnrhon) ig thus obtained in the form of roIonrlcM needles meking at 
229*. h has not hr-cn pafisibl« to replace all the hydrojwn atoms 
in toluene by chlorine; it ha« ouly been coaverted into Ulra- 
<filorobfraotrkhloride. CjHCl,'CCl,,opinti) pcntaefiloii^>auat rMoride, 
C,CI,'CKCIj. On further clilorination. the moleeule spiit^ up. 
Examples of this phenomenon are alwj found in the fatly series. 

The same nieih'ods can be einployed in the prepaiaiion of the 
polyhalfigen derivatives of the honiologues of benzene, at have been 
described for the monohalos;en deiivatives (273)> If it i-a desircil 
to Kulutituie in toluene the nielhyl-hydmgen atoms aJnnc, thi« 
hydn)carb(>n is treated with chlorine or bromine at tlie builirtg-fxiinl : 
there are obtained in succession btnv/l chtnride, CHj'CHjCi. henznl 
chloride, O.H/CHCI.. and benzolrithloridc. C^H^-CCl,. When the 
object is t4> siibstitu(«^' Liydn^gt-n only in the liog, chlorine iaallon-cd 
to react at ordinary temperatures iu presence of a trace of iodine. 
To prepare n ennipoiin<l siifh as CoH;CI'CH,Cl, both methods mu«t 
be employed in Micr!P-'i.''ion. 

Benzal chloride, C,H^CHCi, (B P- 206'), and benzotriehloride. 
G.H, CX'i, {B.P. 213°), are of technical iniiHirtauce, benzaldehyde 
(289) is obtAinoil from the fonncr, and Itensoic acid (396) from t-ho 



latter. 



B4Dieaft«nd Home o( its hoino1ogi]«s nlao yi«ld addition-products 
With cblorina nnil bromine. From lieiiienu is obtained beniene 



DIHYDfUC PHENOLS. 409. 

chloride, C,H,CI„ and bemene hexabromide, C,H»Brg. Both nro ob- 
tained by treating benzene with eicess of the halogen in presenoo of 
Bunlight; the chlorine derivative is known in two isomerio forms. 

nt. POLTHTDBIC FHEHOU. 

313. It was stated in 875 that phenol ia miicli more readily 
attacked by oxidizing agents than is Ixmzeno itself. The polyhydrid 
phenols possess this property to an even greater extent, many of 
them behaving as powerful reducing-agents when dissolved in alkalis. 

Sihy^ric Phenoli. 

OH 1 
The o-compoiind, C,H« j-jti g, catechol (pyrocatechol or pyro- 

catcchin), is a constituent of many resin.*?, and can Ix) pn^parcfd by 
fusing o-phenolsulphonic acid with caustic jKjtash. 
^ Catecho l is cn'stalline anti readily soluble in watiT, alcohrt], 
and ether. It melts at 104°, Its alkaline solution is fir«t tunned 
y --^.^gi^een by atmcepheric oxidation, and then black. Its aqii<><>iiii 
^"^ solution precipitates metallic silver from silver-nit rat*; solution at 

ordinan.' temperatures, and givi-s a gn-ffii colouration with ferrie 

i WH 1 

chloride. The monomethyl ether. C',H4<..j\ ',,. w cailwi giutiacol; 

it is present in the tar obtained by the drj' distillation of i>v*:rh- ' 
wood. When heated with hydrir»dic acid. guaiac(»l yieldn cate- 
chol and methyl ifxlide. 

Resorcind {resorcin). or m-(hhydrrjxyV?nzene, ''tH«</||| -it '^^n 

be obtmned by fiLsing m-phenylenedbiulphonic aeid, C,II^< '^.'u ■,, 

mth caustic potash : this L* the meihfKl by which it ui manufacturrr'L 
It yields a deep-violet ctiouratinn with ff-rric chloride; brominf?- 
watCT converts it into trihromoregarcinol. It u* a «flouri*»LS. cr^>tiJ- 
line substance melting at 1 IS', and rf;adily ^»luble in wafrr. alcihol, 
and ethCT. It quickly turns brown, ouine to the aeiion of th^ air. 

Qunurf (hydiTMjuinone), or p-riihydroxy'r^rrtwrriT. ::j:\'^ at U/fi. 
Its chief characteristic is the hjss on oxi iari/.-n <'• •.■ki, hydrr«^-n 
atoms with formation fA ipiiw/w. (.\H/*. 316 . -TJ<?h ^ r^aJLy 
reconverted into quinol by Tf^vur.i'-T.. Tr.-? t^vi^.^ n5'rK\ 'd 
quinol is employe*! in phot'jgrap'r.y : r -.'rx- ■.'z-^s.ynftz.; '/. tt*T^ 



4tO 



ORGANIC CHEMISTRY 



tive*. With ammoiiia it givos a red-brown oolnuration, due to 
the formatinn f»f rttmplex derivatives, like its isomers, it ia 
readily soluble- in vatc-r. 



Trihydrio Phenola. 



OH I 



314. Pyrogallol (pvmgallir acid}, C,H^)H 2. is obtained by 

XOH 3 

healluQ ffallk acli! (345), CO, b»'iiig split off; 

C,H,(OH)/C(K)H = (VI/OII), + CO,. 

tlallli' HL-lit i'xriiKollul 

Pyrogallol fonns crystals melting at 132°, and is readily soluble 
in water. It i« a stnniK n-durinp-nfrriit in alkaline Mtliition: for 
example. Jt rapidly iilwurijs thf usygt-n of Ihr atiiKisjdicrf, with for- 
nitttionof a brown colouration. J'or this reosctri it is employed in 
gns-annlypis to renicue nxygrn from mixturps. It U also iised as r 
developer in j)h<>tography. 

Am 1 

yhloroglucinol (Bvmmetricai trihvdroxybon2€no).C^,^OH 3, 

^OH 5 
is formed by Fiinng various resins T\Ttli caMstio potash. It w 
crystalline, and pivcw a deep-violot eotouratiim with feme oliloridc. 
A remarkable nynihcsi^ of plduroglucinol lias been diseovered by 
liAKYKH. When aodiomaloiiic ester (166) '^ heated, three mole- 
cules condense, t^ilJi eliminat ion of three inulecidcd of alcohol: 



COOC,H,- 



t\H,0|CO 
HlCSa f.s-^ Hj— COOCjHj 



CO 
.— CN'aC 



3C^0H + 



COOC,lI.-CXa CNa-COOPft 
OC CO 
CNa 



COOC^,H, 



TRIHYDRIC AND HIGHER PHENOLS. 



4" 



On acidifying tliis crincloiiBatkin-product, the wHiiuni atonu are. 
rpplareii hy hydrogpn, witli fonnutifm nf ph^nrixjlucnM^tricnrborylic 
ater. When this substaiiCL* is fused with oaundr potash, tlie 
ethyl-rarboxyl-eroiips ( — COOC,Hi) arc ahstractvii, mid replaced 
by hydrogen, phlorogiucinol resulting. 

Phlurojclucinol should ihurtifure lisve the ooDsliluUon 

CO 

H.U CH, 

I I ; 

00 00 



Yn 




■H, 

in other word*, it ia a bczarnctlij'lcnc in nhiob three of tlim raotliylcne 
Ktoups, =C'H„ hmvn bwit rcpliiwd hy carbonyl, =C0; U atuxi, Ihcm- 
fore, bo calk'd trikttohframrUiijiritr ]l has lieen proTed thxl pliluro- 
gluciiiol doe3 hehn.vd as thoiigli ii hnif thia coiiatitutioai Ihiu, with 
lhn?e niftlcctile* at hydroxy lam inc ii yielOs ii trioxiiuu. On IIju oth«r 
hnnd, plilnroghicinol has lh« charHCUT of « phenol; (or oxaiuplu, tl 
yiHds A Iriiicelale willi acetyl ohloridt;. Ir nists. iherefnre. In tvo 
t.tntoniDric forms, ag n hoxamoT hylonn dorivntivo and Ha trUiydrozy- 
benxcni-: 

It 
\, 



HO 



OH 



hI<|>i„ 



OH 

This is a mnnrkable example of the alt^ralion of the positions of the 
Atoms ithu liyilro(i;«ii of th« Oll-nr^ups] in the molocuie, resultiUK >n 
the convenioii of u benzene derirntive into a derivative of Iiexa* 
methvteno. 



Higher Phenola. 

315 The chief of these is heMilii/flr»xjiit)U«n«, C^'OH],. whoee 
potatsium derivative, potassium oarkmyi, C.rOR),, is fonDed in (he 
}>reparation of potasaiuia, and develops no cspluivo ehAracwr on ex- 
posure to llic :iir (" InorgADlu l.'hLt»i»lry,'*MTj. It can be oblalned 
by henting poinsslum In n current nf airbon (nonoxl(1r>, n ilinvet syn- 
theaid of a dcnvai Ivl- of bcn/nii-. Pimiiluiion vilh ziiii'-tliist coiiTcrts 
tesahyilroiybcn/i.-nn into bi^nKi'nij. It \i a while, cry»lAlline KulMtaiioe, 
and undersoca oimaiion vcr} rcadiiy. 



4" 



ORCMWC CHEMiSTRY. 



IT. QDIHOItES. 

916. Thtt quinonts are gutjstaiicL>s dorivod by the eliminalion 

of two hydroxj'l-hyiirogen atoms from aromatic dihydroxy<lcriva> 

tives: 

CJT.(OH), - 2H - C,H,0^ 

Thp simplest <|iiinonp is henzotjuinoTie. r,n,Oj, and is generally 
rallrtl quitwne. It ie obtained l>y the (ixiiiiilitm of many p-tifTivii- 

tJvTS of bensenr, such as p-aininopiiool C^,<\|.' ., sulphanilic 
Mid, C,H,<^j V, ., and p-phonolsiilphonic aci<i, C,H^<j^ jj y 

and aUo by the oxidation of aniline wit h chroroic acid — tho ordinary 
nu-thud of prp[mratioD. It is (Um> fonncd by the oxidation of 
quinol (,313), though the laiter is usually prepareil by the re- 
duction of <jiiinone. The two other ilihydroxj-benzfnes, (m- and 
0-) do not yield quinones on oxidation. Tlus property is possessed 
only by }>-dihy<ln>xy-i)€Tivativcs of benzene and xia subetitutinn- 
producta, and by higher phenols contaimng Oll-groupe in the para- 
puKition. 

The riulnones have iimially a yetlov colour, and a peculiar, pun- 
gent odour; they volatilizf with ateatn mth partial decomjxisiiion, 
and have oxidizing properties. The coustitution of benzoquiuone 
is best expressed by 

CO 

HC CH 



^ 



Such a formtila requires that Ix-nzoquinone should be a diketooe, 
nndrontaiii two double bonds; its pnipertlfs show that it docs both. 
lt:i kctonic cliaraclcr ia inferred from it« yielding with hydroxyl- 
omiiic first a guincne moMzinu, and then a ^inotu dioxime/ 



C=NOH 
HC CH 



and 



C-NOH 

HC CH 

il » 
HC CH 

C=NOH 



QUSNONiS. 



4'3 





The presence of double bonds is proved by its power of forming 
additiou-products; benzoquinone Id chloroform solution can tiUce 
up four atoms of bromine. Accortling to this oonstitution, Ixmzo- 
quinone is not a true benzene derivative, but the p-diketoite of 
a dlhydrobeDzenc; 

CH, 

/\ 

HC CH 

The forrnfttion of benzoqiiinone from quinol is. another example 
of the conversion of ec-iilriL- bonds into double bonds when two of 
the former disappear (270); 

C-0 

HC/NlH 

\)H C=0 

Some apparent exceptions to Uaber's Bchemc [292) for the 
electro-reduction of nitrocompounds may be mcrtione<l here, be- 
eauac they are cxplaineil by aasuininK tlial iiuirmiic drrivativcs are 
formed OS intcnnediate products. The?*' exceptions havii Ijcvn 
observed in the reduction of hij^her-aulistitutpd ritrobcnxenc <leriv- 
Atives in alcohol if-alkaline Holution. According to thp srhpmr-, azn- 
derivatives shnul)! Ih' the chief pri»dut'ts under tliese ciituiitioiis, 
whereax it in found tiiat in sonic inslunces amincit an- prine-ijiiilly 
prxMhicifl. Thus, ilic main proiluct obtained from p-nitniiiilinr i<t 
p-plienylfiKiiiuniinc, whili- under the same conditions m-nitrtuiiline 
in a normal manner yields m-dianiinoastobfnBPno. This difference, 
however, is rradily explainud by the fact that p-nilratiilinp gives 
rise to (jiiinone derivativt-s, whereas vi-nilratiiliiie d<K« not; tin 
reduction of p-nitraniline to the corresponding hydroxylanmie, the 
latter readily splits off one molecule of water, yielding quinonc 
di'iniidc: 

NH,-C,H/KO, - NHj-CJI/XrrOH - Mr:fVI,: Nil; 

ti ViimnlliriF* f--Vniluc>|ih»')*jrlhjfiJr"iif limine yu»iiiiiiu tli>iEjild« 

and the l&ttcr in readily retluced to ;>-plienylcnedianiine: 
NU:C-,H,:NH + 2H - H,.\'-(J,H/XH,. 

^•I'tlrll> loilnllAIIIIDK 



4(4 



ORGANIC CHEMISTRY. 



m-Nitruiiilinc is unable to form a <(uinunc ciRrivative, and is, there- 
fore, reduced normsily in ftccorrlance with the scheme 

TetnKh}oro<iiitni>ne, or chlornntl. C,Ci,0,. \* oblflitK-d by the ao-'J 
tioii uf chlorine i>n etui none, and iiino by thU'UXifhiliuiiofiniitty organl 
8Ubstnnu(« with liydroclilorii! ncld mid potAHSiiim cblorate. It Eornu 
yellow, glistening k-uvm, ni\<\ is nn oxidizLRS-ageiil. 

817. Pontamothyl^ne yjoliis r^markAble quimmoji. obtAiacMl by th» 
oxidation of hexnhydroxylciiKcno in nlknlinc Hultiiion. Among them 
U<:roeoiiic add, CjlI,Oj, which has an intcnae yi>l!o«" ootour, ftod Is 
convuru'd Ijy wwik ri^iliicinK-ngiiTits iiiio a colourltvu subatancc, from 
wliifh eiviooTiic fict'l onii bo oblalncti hy oxidntlon. On oxidnlion, 
croconic uuid ia trnnfiruniiud into Icuconia add, C|0( -f 4B)0. ThU 
eompautid has tho consti union 

CO -CO 
Oc/ \C0 + 4H,0, 

ilnc« it yioMs a pontoximo or th« fnrinulii (C: XOH],, 
V. POLTNITBO-DEBIVATIVEB. 

S18. m-Dj'ni'/rotenzfnf is obtained by the nitration of benzene 
with a mixture of codceDtratdt sulphuric acid and fuming mlric 
acid; it forms rolniirlests needles melting nt 00°. On reduction, it 
yields ni-phtti'/fcncciiamine, and is on this account, employed in the 
preparation of aniline dyes; it is also used in the manufacture of 
exploKiVL'g, since it can be exploded by merciin,' fulininato. In 
addition lo the m-conipciund, sniull iiuaiititii'S of o^tniirobenume, 
and traces of the fy-iienivtit-e are formed. On stronger nitration, 
effected by a mixture of nitric and fuming suljihuric acids at 140", 
m-dinitrobenzcne is converted into sifmmeincal trinitr 
(1:3:5), which mcH« at 121*. 

The hydrogen atoms and nitro-groups in the polynjtrobenzenee 
are much more readily replaced than those in mononitroljenzenG. 
Thus. wj-dinitroljeri7.enc is converted hy oxidation into dinUrophmal, 
and trinitrobcnzcnc into picric add, or trinitrophcnol ; 

NO, NO, NO, NO, 

TJO, ^^O, ^JO, NO, 



POLYmTRODE/UyMTifES /IND POLYMMINO-COMPOUNDS, 415 

By the notion of sodium ethoxidc anil methoxide respeelivelj-, 
one of the tiitrogroups iii o- and p-dinitrobpnxeJie can be quanti- 
tatively replaced by OC,H, and OCH,: 

C„H,<-;;^ + NaOCH, - CJR,<^^* + NaNO^ 

It is remarkable that this fcubstitution docB not take plaee vritta 
m-duiil robetufiw. 

When boiled with caustic soda, o-dinitrobenzeiie yiulds niiro- 
phenol, and when hi-at*d with alcoholic ammoiua, nitranitinc: 

;N0, i+NaOH yOH 

C^,< NaNO, + C,h/ . 

XNO, 2 \nO, 

n H- ^NO, 1 -J- HXHj _ ,. „ ^NHj , ,„.,. 
^""«^N0, 2 '"•"*^N0, "^ ^^^^»- 

TrinitriAufi/lxi/hiii; coalHinlng a [ertmry liutyl-groui). bun an 
odour rcsombhn^ musk. It u sold under the iiiLni« "ftrtlflclAl 



TT. POLTAHIXO-COHPOtTHDS UTS THEtB DESITATITEB. 

819. Theap are obtainrd by the n-duntion of pnlynitro-derivo- 

tivca. m-Pheniflenediamine, C,H,<».tr' ,, is got from benzene by 

nitration and sul(si'<]u<'nt riiluction. 

The p-dcrivaiive can be prepared by the reduction of amino- 
azobon>!etie (304) with Lin and hydrochloric acid, ajiiline and 
p-phenylenediainine I>fiiig fonnyd: 

+ H,.H, 

OrtA^Mliamino-com pounds react readily with l:2-diketone9, 
yielding (luinoxaliTiea : 

- ( ] T +2H,0. 




H, 



Like the polyhydric phenols, the polyainino-eompounds are veiy 
readily oxidized. Tbey arc coIoOrless, but many of them arc turned 
brown by oxidation in the aJi. 



41 6 



ORGANIC OfEMISTRY. 



Au-dyu. 

320. The azo-derivalivpfl of the polyamino-compounds are 
known as ajo-rfi/c-8; ihpy are or great teclinieal unporiance, being 
extoriMVcly employed in ilyting wool, silk, aiid eotton. Tbey are 
asobeiiBenes in which hydrogen aloins have been repUced by aiiiido- 
groups. These are not the uiily dyes; derivatives of aiobenzcnc 
in which liydrogen ia replaced by hydroxyl or by Uie sulpho-group 
can likewise be aaploycd in dyeing. Some of these will also be 
described here. 

It, Ls finrt npocssary to state certnin facts reganling dyes in 
general. It has been pn)ve<l by experiimce tliat it is not by any 
means evcr>' colon ring-matter which can dye the eulx«tai)cea 
itaiiivd aljovc; that ia, colour thtin so tliat the dye cannot siibtse- 
quciitly be reniuvid by rubbing, or wasliiitK with water or soap. It 
is, therefore, ncccssarj- to make a distinction between eoloured sub- 
stances and dyes; for exampJe, aKotjcnzene has & dwp yellowish- 
r«l colour, but is not a dye. The introduction of an aniido- 
groupj however, converts it into aminoaitobenzene^ which is a dye. 
Witt has j>iit forivanJ the theory that the coU>uring-f)owrr of a 
Cf^Ripound dcp(;ndi3 upon two fuc:tors. The; tinil of these is the 
presence of crrt-ain groups, which he e&Ms ehromophons, among 
which are the azo-group. — N^X — , the nitro-proiip, and othcK. 
Subslorces containing a ehroinophore-growp, along with XH,, OH, 
SO,H, or in general a group which imparts to them an acidic or 
basic eharactfr, are dyee; this is ilhistrated by amiiioazobenzrne. 
Another example is nitrobenzen*-, which han a paic^yellow colour, 
and contains the chromophore nitro-group, but i« not a dye; on the 
other hand, p-iiit raniline and p-iiitroplictiol are dyes. 

SSI. ]n iiinny cases it is sii9iuiE<nt loimitii-rsu I ho silk, woAt, orcoi* 
Ion to be (Ijed innsolution'of the clyo. Binoc it wiu dissolvi^ at flnu 
bttt cannot bo removed by washing tbo fabric HHer it faas boeiwlyi.'d, ibr 
dye must linrc imJrrgoiiu u cIiiiDgc. It is iiMuninl ttint it uniuu villi 
the coiiMitui-tita of the aniinnl or vegctnbta 0br«:( to form a ootiapouiKl. 
a kind of .salt, Riiice dyta alnaya have a Iwsic or ocldio ctianictcr. A 
proof of thifl will bo given for rManiliae (ifJ). 

In other cases the t»Me ilnes not tiiko up the dye when Immersed 
in ite solution ; it hns boeii repeatedly obserTed that dyed which be- 
come direrlly flieilon nDimnI fnlirics, etich as silk and wool, do nut 
dye vt>)i<'tftb]« fnbric^. like cuttoit, tinlees Iho nalfiriid to bo dy«1 has 
nndergiUMt a sjiwiid prtK^ess, called mordatilhig : thnt is. n Biilistnnoe 
muat ^jo HfpoKiK'il iti rbe fabriu lo^ the dye, siiwe llio laruT u-ill ttat 



AZODYES. 



417 



oniio with tbo fibres theTngvH-ps. Such siibelnnoeB AN OftUad nmnlanUi 
th«y kro iisitdlly salte of woivk biuv«i or nckt« ; la^h WW RlaBtinium 
acetate, farrio B^ils, compounds of tin ("pink salt," 3nCV 8NU4CI), 
Tlie woieii mttlerial itt tboruuKbly soaked iii a solution o( one of these 
•alts, and tlwu sprt-iul out and exiKAcd to ilia uc^tion of ntfinm nt a 
euitablo temperature. The tail uodcrgoM hydrolytic dooompoaUion, 
and the base or aoici, far example slumiiiium hydroxide, or alnniiic 
acid, u deposited Iii a Qqg al«te of division iu Ibo fabric. The dyo 
aaitm vHh thiH baite or avid, forming an insoluble coupound wbich 
>a not romovcd by waahiug. 

322. Azim1}'(« ore (ibttuneU by treating diuzMitiuni chlorides 
with aronmtjc amines or with phenols : 

CA•^^iMIHi<f~">^'(CHO, = C,Ha-N:N-C,H,-N(CH,),+ HCI, 

IlliuiauEum cUoriJii liJuMClif luiilliui UliuvtbykiiilitcibuuaiTaa 



C^- N, ja+51<^~\0H = C JI,- N : N ■ C,H.- OH + J[CI. 

HTdraijrBiiibiniiR ar 



when l>asiiT anrl noidip dyes ari> rrspetrtivply prodiirrd. It was mcn- 
tioiied in 304 that the rDnihinatinn of a dis7oniiini chlnridc »nd an 
ammatio amine smnrtimcs yields the diflzoamino-compound as an 
inlcnncdiatt- product, which rait l»r wHivrrtrti Int^i thr aminnaiio- 
drrivalivc hy vonninp wilh the atiiiiic hydnjchloridr. In lliia 
fnrmflliol) of aminnazn-pnni pounds and hydroxynzo-t-onipoundF, 
the para-II-atnm always reacts wnth the diazonium chlorido; when 
this atom is replaced by a siilM%titnenl, the formation of dye either 
docs not take place or is verj- incomplete. 

t23. In prcimring hydroxyazo-dyca, llm solulioii of Lho diaTniiium 
cliloridD ia kepi vool niih ice, and is slowly added to the alkaltne naiu- 
tion of tbe pbcnol or iu niilpbonic ai-id ; caru in talEcn to keep the iv 
aelion-miximv !iliL{htly nlknliiu<. etinco nthcrwiso the liyilKiohlurlo acid 
liberaliNl w-uuh) tiiiidci' thu forinntiua uf tb<! dyi?. After (he sotuliona 
haro been rtiisi>d, itiv dyo it "uilled out " tjy ttui.iildition uf t'otnmon 
salt, vhicli pTticipi intcs it iii flocculcut mnucs. It is frvcd from water 
by m«^ia« of fili(<r-praiwos, and put 00 the market ettbor in the dry 
state or as a paste. 

Aminoazo-dyos st\> prepar<Ml by mlsln; lho aqueouit golulion of the 
diaxciiiuni cUlohdu nilh that at thc^iri^aiutioniniuoMiIt, thccolouring- 
iiiatter Iwiiig Mib«u<)iii>nlly enltvd out. It is Kutnutimes iioowuary to 
omploy an idcolinhc soluiian. 

Tbesimpleat nzo-dyesaroyi'llow; on the iniroductJonoralkyU^roups 
w pbeuylffroujifl, and iu ^'envral ou iuoreiase of nioleciilar weight. 



ORGANIC CHEMISTRY. 



thoir ^lour changes through ornngo nrul rod lo violot imd bine Thvy 
arc crysulli lie, and meat of tb«Ri iiro iosolublo ia water ood soluble 
in alcohol. Itisl^iid of tbo axo-dyvft tlietna«Iv«a, it is often be(t«r 
1« vmploy ihoir stilplKniic ucitls, ubiainiil)l« from Ibem by the asn&l 
in«tliod — trcniiQctit. with concoutratml sulphuric actd. 

324. A sliort *lct«-pip!ion of some of ilieeedyea nmy be giv-cn here. 
AnUin^ydlov! is a salt of iiminoazi)b«'iuene; it is now Beldom 
uaed, its place having bwn taken by oLht;r j-cUow dyta. 

Chn/aohline or diaminnaziibptiwne, C^ij'N:N'C4nj<^|»', is 

obtaiaed from bfiizeiicdiaionium cliloriile and jri-phcnylencdianiinc. 
It yjelda a Iiytlniclildridc. crviitalliKinK in nwrdlcs of a nxtdisb colour 
and fairly i^uluble tu watc-r: titb salt dyua wuul and ailk diructly, and 
cottr>n wiiich hax bwii niordamc-d. 

Sistnartk-broum, XHj'C.H/N ;N-C9H,<;^-jj', (triaminoazo- 

beniton^?), is manufactured by diazotiziiig oiic of the NU,-Broui 
in 77i<plir>ny|pnrrliain)iie, and lit-ating tlic product Ibus obtained 
with a sevutid molecule of tliis bas« : 



IICI + 




.:<^xa. 



Nil, NH, 

Even a rcry dilate solution nf nitrous noid gites a broum oolonra- 
Uou with frcpbcDylttiicdiauiiDt, due lo tbo ronnalioii of Btsmarek- 
browii or n'hiuil KulM^tnixioit : lliitt ivaelinn furnishes a rery delicaie 
twt for iiiiroiis ncid, mid is coi^^ivyud in vrntvr-aiinly«i». 

Hf^Jinthine, or dipioiUvliuninoaz(ibi'niiiJr iPM |lphariip Afitl^ is pro- 
pnrcfi liy the intpraelinn of bptuoiidliazoniiini initphonic add 
dimcthylanilinc hydrocldoridc in atiueous solution : 



HtyS C,H/N,[ OH + H |C,ll.-.\'CCJi,), - 

- HjO + HO,S-C«H,-N:N'C,H,-X(CH,)^ 

II is not ofti-n used as a dye, but its sodium salt, which has a yeDnw 
oolour, and Is turned red by acids, is employed us an indicator in 
volumetric atialyslH under the name jnelhyl'orange. 

Rt90Tvin-ytlf/w, HO^CaH«N:NC,H,<yJJ, (dihydrosyaio- 

bcnxenpBulphoiiic acid), is oblainetl from tcsorcinol C31S) ojid 
bcniEcnediiLZoniurn sulphanic acid. 



PHTH/tLlC ACID. A^9 

The diazo-dyes are split up into aminocompounds by energetic 
reduction with tin and hydrochloric acid. Thus, aminoazobcnzcne 
yields aniline and p-phenylencdiamine : 

C.H.-N=N-C,H,-NH,-*C,Hs-NH, + C,H,<5;Jg|J. 

This decomposition on reduction affords a means of determining 
the constitution of these dyes, and indicates the nicthods by which 
they are obtained. For example, Bismarck-brown is converted bj' 
reduction with tin and hydrochloric acid into a mixture of equi- 
moleeular amounts of diaminobenzouo and triaminobcnzene. Since 
the molecule splits up at the double bond of the azo-group, it fol- 
lows that the constitution of this compound is 

NH,C.H-N:;X-C,H,<JJ2'- 

This also indicates that the dye can be obtained by diazotizing a 
molecule of diaminobcnzcne, and treating the product with a 
second molecule of diaminobenzene, in accordance with the equation 
on page 418. 

Til. FOLYBABIO ACIDS AND TEEIB DESITATITEB. 
DIHAS1C ACIDS. 
325. The dibasic acids arc the most important members of the 
series of aromatic polybasic acids; they are called plilhalic acids, 
a name derived from naplitlialvnv, from which one of them can be 
obtained. Three isomers arc possible, and all of tliem are known. 
Like all polybasic acids, they yield neutral and acid esters and salts, 
acid amides, amino-acids, etc. On distillation with lime, they are 
converted into benzene. 

Phthalic Acid. 

Phthalic acid is the oriAo-dicarboxylic acid of benzene, and hes 

the formula, ^•H,<™^,j, „■ ^^ is obtained by the oxidation of 

aromatic hydrocarbons with two side-chains in the or(^o-position, 
or their derivatives with substitucnts in the side-chains. It is 
worthy of note that chromic acid cannot be employed in this 
oxidation, since it splits up or/Ao-derivativcs (completely into COj 
and HjO. Phthalic acid is employed in the preparation of artificial 
indigo (399), and is manufactured by oxidizing naphthalene (370), 
C,oH,, by heating it with very concentrated sidphuric acid. 

Phthalic acid is crj'stalline, and readily soluble in hot water, 



K^ 






,^.yr 



ORGANIC CHEMISTRY. 



.O A itfkohol, and rther; it has no definite melting-point, since on heat- 
ijtf (y ing it splits off waU'r, yielding phtfialic anhydride, which sublimes 
in beautiful, long ncvJU-s : 

Ces—Or- 

326. If tho' fnllowcd the onlinary ruursc of the reaction form- 
ing acid chluridt-s, iihosphonLi pentachloridc and phthalic acid 

would react to produce a chloride of the constitution ^'(H«<pJ^. 

That they do not, and that ph0)alyl chloride has the structure 

CCl, 

can be proved in varioiis ways. When aluminium chloride reafitS^ 
with fihllialyl chloritle in presence of benzene, tliere results a com- 
pound nith the formula 

>0 . 


called phlhalophejume, whose ennstitntion follon-s from its formation 
by the elimination of water fn)m tri phenyl carbinolcarljoxy lie acid: 



C,H / \o,H- 



X-OIOH 

Triphnnvlrai'lilrKil. 
carliuxyllc uviil 



-K/) = C,H. 



\x) 



>0 . 




llitliBlophMioDa 



Another proof of the conslilution iiidieated above for phthalyl 
ehlnride is the fact that, reduelnii-agenls, such as sodium amaljeam 
Bn<l water, or zinc and tiydrucltloiiL- acitl, caiwe the replaocmcnt »f 
its halogen atoms by hydrogen, with fonnation of phlhalide. This 

-CH, 
substance has the constitution C,H,i >0, Binco on treatment 

XX) 
with caustic soda, it yields hydraxymfthylhrnzoie add ; 






^COOH 



This proves it to be a lactone, and not a diatdchyde, C,Ht< fiiiy as 
would be cxpcctud if ttic formula of phthalyl chloride n-crc 

327. The oxygen of the carbonyl-group in phthalic anhydride 
can also take part in other reactions; thus, when this substance ifl 
heated with phenols and sulphuric aciJ, phl/uUeins art? formed: 

/C,H.OH 

H,o + c>H,<; >0 



C,H.<f|L 



+ 



W^ 



CJI.OH 
O.H.OH. 

I'boiiul 



ri>«iioiphiiMWii 



I 



mUiaJlcaiihjilrEilo 

Phaudphthnlcin, thn fiimplcst member of the phthaleiii series, 
ia a yellow powder; on account of its phenolic characttr it dieaolvcs 
in alkaline solutions, with formation of a fine red colour, and is a 
sensitive indicator for alkali tiic try. 

Reteorcinol-phthnltm or flxumscein Ja charaetprized by thn display 
of an intense yirllowiah-grwii Huortscence in alkaline solution. It 
owes its name to this property, which affonls a delicate lost for 
phthalic anhydride, i)lilliulir iicid. and iiMorcinol, Kincc fluorescence 
Ls exhibited by tncrc tracf» of lluoruact-'in. It ia preparrd by heating 
■together reBoreinnI and phthnlie anhydride at 210°, in presence of 
xinc chloride as a d['hy<IratinK;-ajiPiit. <>ii trvatmont willi bromine, 
fluorescein yields tctrabromnfliKtresceiii, whose pota-ssium deriva- 
tive, C,ftH,Br,0,K„ I' the beautifhl dye, tmin. 

niie constitution of the phthftlrins is infrrrerl from their being 
convertible into derivatives of IriphcnyUnethane (366). 



328. f'hihalimide. C^H^t^ >NH. is of importance on account of 

it» application by (Jaiikiki. Ui l!io synlhosis of primar>' ninincs with 
guhstitutpd alkyl-gnnips. It is obtained by passing dry ammonia 
over heate<I phthalir jinhytlridi-. The iinido-hydrogen is replace- 
able by melali^: tluiH, thi- potassium compound is precipitated by 
the ai'tioti af fau«tie i>utush upon the alcoholic solution of the imide. 
Wlien potassium phthtihmide is treated with an alkyl halide, the 
mi*lal is replaced by ulkyl: on hcntinj; with aciils or alkallt;, a 
priinarv amine, free from secondary and tertiary amines, is split 
off: 




CHEMISTRY. 



yGO 

I< >N 



ejl*< >N|K + Br|C;.H„., 









®-h«<^nI + nh,c.h^... 



Variously suhsiitutcd alkyl JialUIwf caii be employed in this 
n-action; thus, from ctiiyU-nL' brotiijcle, CHjUrCH.lir, is olitaiiiLii 
bromoethylamine, XHj-CHjCHjBr ; iwtu Kliykocbromliydrin, 
CH,Br-CH;OH, hydroxtjfthytamint; \H,-CH,-CH;OH; etc. 

Anntlier nxniiiplc is ICuiL Fisii»:hw syt\\\\csm nf omUHine (200). 
Putassitiiu ptithuliniide u bruugbt into contact wtlb trinietbylene 
bruiuiilc : 



-CO 



e^<^.X>N| K + Br lCH,CH,CH^r 



.CO 



C,n,<^^>N-CHaCn,CH,Br. 



The componnd cbtauicd is treated with cthylsndiomatonate, and 

yiclda C,H, < ^ > N 'Cir, • CH, ■ CU, ■ CH(00OC,H()„ wliusc icrliary 

hydrngrn ntom c-uii be siibKtilutcd by braniinc. Saponification 
and q>lltting off <»f CU^ give 

G,H,<^>NCH,CH,-CH,-CHBrCOOH. 



Jy heating with aqiieouB anuiiunia, Br is liuui roplacwl by NH|. 
Subsequent heating with concentrated hydrocIUoric acid yields 
ornithine: 

G^<^>NCH,CH,-CH,-Cn(Niy -COOH • 
+ 20HH 

- G.H*<S2^S + H^CH,GH,'CH,-CH(NH,)-eOOH. 

These examples make it eviricnt tliat this method can be ap- 
plied to the preparatJoQ of tbv most variously substituted primary 
amines. 



ISOPHTH^UC MSD rF.M-PHWAUC ACIDS. 



•4*J 



39fl. UoooewERPr and tak Dorp found thAt ammonia reacU with 
pbthalyl uMoridc, jieldiiig o-cgaruArtuolc acid. C(H,<qqq|.; it 
most be usumed tbat nu iso-imidt of phtliallc acid Is formed as an 



latcrisedlfttc product : 




cliUirMfl 



c=Nn 



o,n,<'> 



CO 
Uo-lm.lde 



yCN 

x;ooH 

a-Cyanabctiaola 



Allbougli tlioy have uot been ahlo to isolate th« iBO-iinide tbelf, they 
bnvv pro))arot] n numl>er of UeiivacivM in which tbo imi do- hydrogen ts 
replncod by hydrocnrbon-restdaes. 



liophthalic and Terephthalic Acida. C.ir,{COOTD, (t; S) and <1:4X 

330. liffphthaUf. tv^Ut can bo obtained by the oxidation of com- 
fwuiKls with [WO Hidc-chaina in ibo wirtn-posilion, nnd also by tbo 
oxidAtinn of r^in (coloikhotiiuui) uitti iiitric ociO. It diasolvea mth 
dilGculty in vaier, nnd does notyJf<ld na anhydride. 

TfrcfihtTiaiic acid enn be pivpnred by so versl methods; fflrciAmpIei 
by ihi- oxidnliuii »f lurptintiiif. !t is rilmo.u insoluble in naler, alcohol, 
Riiil L'thur. It d'K'K iiiit iiK-U timlcr ilii>ordlnnry prr^unni, hi]l«t high 
toiiiperaturi-5 sublimits wiibouL decora positiou. Like tho iao-ocid, it 
does uot form an juiiiyilndo. 

HIGHER I'OLYBASIC ACIDS. 

sat Tried rboxy1i(!, lotmcarltoxylic, pentacarboxyllc, and hexa- 
earboxylic n.e\t\< iim known. The inoitt rfimnrkAblt; U tho Ifuit, mdliHe 
acid, on nccounC of it« pi'oence iu lliv miuiTiil ttoney-ftone, found tn 
browu-coul sesniA. Uonuy-slono \i thu nluiiiinum Milt of aaollitic Mid, 
and \n\» ihc forinuU C,.0„A5, f ISII,0: U forma yellow qii.idrfillo 
oclalii?dra. MelliLiu avid m prodiid'd by tho oiidaOon of wood-charconl 
with an alkidiiie solutjon of poi;ii<sium poriDanfmnaie iM). It oo'^i^l- 
Uzii» in Qne needles, aud is readily solubls in water and alcohol. On 
hoMiDg. U loses tvro molecules of carbon dioxide and two moleoulmoC 
water, with formatiou ot pgrvmeUitie anhj/drid*, 

which takes ap water, and Y\e\As, pitromtiatie acid, C,H,(0001]),. 




DERIVATIVES CONTAINING TWO OB MO&E DISSIIULAB 

SDBSTITUENTa 



r. nTLPHO-DEEITATITM. 

EalogCD Sdlphonio Acidi. 

332. Amon^ Uiesc may bi- im-iitiuiirtl the three bivmobeTuene- 

stdi^umic adds, iHi of which yield reflorcino!,X),H.<j^|r -,, onfuiaon 

with caustic potasli. This is one of the c»impsratively few cases of 
substitution in which the substitutinK- group occupies a different 
po^iliun from the one rpplapeil by it, Othor similar e3C&mplea will 
be referred to later (352). 

PhenolanlphoDic Adda. 

383. Oiiho-phmohulpliariir anil itg,Ta.-pht7iolsulphonie acids arc 
obtainod by dissolving phenol in concent ralwl sulplmric acid; ih« 
ta-arid is prYKlucod wbtn ni-bcrizcncdwu I phonic nriil is fused with 
caustic! [KiIbhIi. The o-acjd in cljamcttTized bv bfiiig readily con- 
verted into tlip p-cf)mp«und, even <wi evaporBtloti of its aqueous 
sobition. PIiciioI i« much lutiff n-adily Milphonnted than beiuene, 
its solution in Kulphurir acid In-iiiK t mnsftrntird intn the two above- 
mentioned acids even at ordinary tciupcTaturcs. 

rtPlionoUiiIphoiiTc ftptd is emplnjed as an siittiip[»i<e unclar thp 
nanifl "(kve|it«]," or "wMtolic jitid." Pi-ifntopii/tatofsttip/ionie add 
Is also tised for llio Kame p(ir|KMc, under the nsmo "MKtolodoL" 

p-Aminobenxenesulphonic Acid or Sulphanilic Acid. 

334. Svlpfianilic ucid is obtained by hcutiiiK unitincwith fuminf; 

milphuric ocid. I jkc its isntncrs. it is soluble with difficulty in cohl 

water. Tiic basic prnp^Ttics of aniline air grpatly wpiikcncd by the 

introduction of the sulpho-f^oup into the rinR, for sulphanilic arid 

cannot yield salts with acids, while the sulpho-group reacts \k\\\\ 

bases, forming salts. The fonnula of sulphanilic acid is probably 

SO 
C«II«<»u* >; lliatis, it ia an iimer salt. On fusion with caustic 

484 



SULPH/fNtUC AOD AND SACCHARIN. 



4«5 



potaah, it does not yield aniinophenol. tia might be ejcpected, but 
aniline. Oxidation with chromic acid converta it into quinonc. On 
pouring a mixture of eodium sulphaniUtc and sodium nitrite In 
aqueous solution bito dilute !«ulphunc acid, an inner salt of itemene- 
diazomum sulphonic acid is precipitated, as it is nearly insoluble in 
water: 

This compound is of great importance In the preparation of aSo- 
dyesBUch asA«/uinfAtn« (324). 

SolphobeDzoic Acids. \ 

835. Tbe imido-dcrivative of o-sulphobenzoic acid, 

luiown as saccharin, is about three hundred times u BWect as sugar> 
and on this account is 8om(;tinie« t'lnploytMl as a substitute for it, - 
Direct stilphniiation of Iwiizoie acid yit^lds m-aulphoht-maie aeut 
alnioel exclusively, so tliat saccliarin cannot be prepared by this 
means. Il is obtained fnim tolufiie, which, on tn-aluivnt with 
sulphuric acid.yiddf* a uiL\luro uf f^- and o-toltceitcaulpftanie acidt, 
the f<irHivr IwiiiK the chivf protluct. The o-acid is converted into 
its sulplmmide, the mclhyl-p-ovip of which 13 then transformed into 
earboxyl by oxidation with potassium permanganate. On halting, 
this oxidation- product loses one molecule of water very readily, 
forming Mic<'b»nn: 

fkSiilpljHiiiidt- lit loT.inTi.' bimI SaruJisrlu 

Saccharin is a white, cryslalliue powder, soluble with difficulty 
in cohl watiT, und readily Bolubk- in alcohol and ether, 1 1 takes up 
one molecule of water, yictdinR the suIphamideoE o-sidphobenzoio 
acid, wliich docs not powtes-t a swert tnste. 

U. BaiMEH CEKIVATITES. 
Halof^en ^henola 
336. Orlbfw7i?nrop/i»-iio/ and psrH-c/i/omp/ifTiof are formed by 
the direct ctilorinatiou of phenol, and al»o by reduction of the 



42& 



ORGANIC CHEMISTRY. 



balogcD nitro-benzpnes and subBcqiient cliazotization of the com- 
pounils formed. They have a pungent odour. Uy fusion with 
caustic potash, the haUigpn can be replaced l)y hydroxy), although 
it 13 not always the corrt'siMJiidiiig hydroxy l-«jiii|M)UiHt wluch is 
formed. Tho inljiKluctiim of halogen ronsiilcrahly augmtrnt* the 
aeidir charartf-r nf the phenols; thus, trichlnrnpheno] decomposes 
carljonatcs. It was inrntimirfl in 276 that, the presence of hydroxyl 
in th« ring corsidcrabiy fa<'ilitat(w the substitution of Ihp hydrogen 
atott].s by haloKPii. Iodine, however, can only substitut* ia pres- 
ence of an oxidizing-agent, to remove the hydriodic acid formed; 
since, uidess this were oxidized, it would take away the iodine atom 
froR) iodophenol. 

Halogen Benzoic Acidi. 

837. 'Vhv mH:(imp(nimi ran be obtained by direct chlorination 
of benzoic acid, but can be more readily prepared by diazotising the 
corresponding amino-rrnnpound. This is also the best method for 
the preparation of the wrtAo-halogen and pnra-halogeii benzoic acida. 
Phosphorus pentarhloride does not react readily with lUe hydroxy- 
boiizoTc acids; hence the halogen benzoic acids caiinot be satis- 
factonly prepareii by its aid. 

As would be expected, the acidic character of benzoic acid is 
strengthened by the intriKluetion of halogen; the diesociation con- 
stant /C of Uu- halogen beiizoie at-ida \& greater than that of hejiz- 
oip api<l itself. Fur benzoic acid, K is O-Oofl, for o-ehlnnilienzoTc 
aeiil 132, for m-chlorobenzoie acid ()■f)l.^.'>. fur /M'hloroI>enzoTc 
acid 0-0()9.'l. This shows that the chlorine atiun in the wrtAn-posi- 
tion exercises the greatest influence and that in the ^JCim-pofution 
the least, wliile for t he m-eompound K is iiitenuLHliate in value. 

Combinations of halogen wit h l he .sulpho-group are referred to ia 



nZ. STDROXn. OBBITATITZS. 

ITitni&opbeuol. 

838. This compound reacts in certain respects as though it had 

NO 

the e^institution ^i^*<i)i{^ although it*) (onimtiou from quinone 

and hydroxylamine points to the constitution C^^„ . It is 

formed by the action of nitrouB acid upon phenol, or of caustic 
>8sh upon nitrosodimethylaniline: 



mrROSOPHENOl MND KtTRCM'HF.NOLS. 



4J7 



¥ 



•^* OH " » '^OH ''■ "*°* 

0N<^^fN( CH.)7T"?| QH = H.\(CH,), + ON<^^OH. 

Like other oximes, nitrosophenol, or quinone oxime, unites with 
It ifi a colourless compound, pr>'stflllizinR in nrodlcs which 
won turn brown on exposure lo air. On oxidalioii nnd roductinn, 
St behaves as t1iou|rh it were nitrosophenot, yielding nitrophonol 
and aniinophenolrespectively. 

Vitraphenola. 

83B. Tho increased rcfttliiicss with which the hydrogpn atoms of 
the nucleus can bp substitutpd after a hydroxyl-groiip has been 
introduced intn henzcnp is illustrated liy tin? behaviniir nf the 
- phenols InwaniB nilric acid. Wiiilr it in ni-rcissiLry to i-nipliiy mn- 
centrated nilric acid in order to obtain nitrobenzene from bt^nzone, 
phenol is converted by dihite nitric aeid at low teniperatnres into 
wfAo-nilrupiienol and pnrfl-nilrophoiiol, 'lliese two iauniera ean be 
BSparated by distillation nitli steaili, with which only the or(Ao- 
compound is volatile. Mela-mi'i'ropArTiof ean be prepared from 
mrfH-iiitraniline by the diazo-reactinn. ^r/Ao-nitraniline and paror' 
nitraniline, but not mcta-nitramlino, yield mlrophenols directly by 
fusion with potash : 

NH, OH 

Qno.' '"" + """"^ ^ CTo. '"" " ™- 

NO, NO, 

Tlua shows that the suhstitucnts in benzene ore mueh more readily 
replaced when there are .several of them than v^'hen there is 
only one. Thpaddie charaeler nf phenol is strengthened in the 
nitrophenohi ; they ilrrnmpnsf! all rnrhnnatcs, although nitrophenol 
is precipitated fnmi a solution of an alkali-nitrcipheiio.xide by carbon 
dioxide. 

340. The best-known nilrophenol derivative is picnc add, or 
l:2:4;6-trinitrophcnol, 



NO. 



NO,<i 




OH 



1/ 
NO. 



4a» 



ORGANIC CHEMISTRY. 



This substiLnec has long bM-n kiiown, and Is produced by the action 
of concentrated nitric acid upon a large vaiiety of substances, such 
as silk, leather, remriH, aniline, indi^. rtc. It is prepared by dis- 
solving plicnol in concentrated sulphuric a«id, and carefully adding 
small quantities of this solution to concontrated nitric acid of 1*4 
sp. gr. An energetic reactidii lakes place, after which the reaction- 
nuxtUTV 18 wanned for Koria> time on a w&t«r-bath; on cooling, 
picric acid crj-slalliw-s out. It cannot be further nitrated : in 
other words, it is the ftnal pruduct of the action of nitric acid on 
phenol. Tliis explains itjt resulting from the action of nitric acid 
upon such heterogeneous 8\ibstances. 

Soli^l piprie Beid has only a ven,- falrl-yellow eolour when pure, 
but its nqunous solution is deep-yellow. It is a strong acid, and, 
therefore, undergoes considerable ionization when ilissolv-ed in 
water, the yellow colour being characteristic of the anion, since t.he 
solution of this acid in petroleum-ether, in which no ionization 
occurs, is colourless. It ie eillghtly sohible iu cold wat«r, and is not 
volatile with steam. It molts at 122°. 

A coiiaideration of the fnllowing reactions ahowa that picric add 
Is comparable with Ihi- rarlioxylie acids. Phosphorus penta- 
chloride repUces the hydnixyl-group by chlorine, with formation 



of picryl chloride, ' ^j 




which has the character of aa 



acid chloride. Thus, it is decomposed by hot water into hydro- 
chloric acid and picric acid, and with ammonia yields picramide 

^^^mv'^'l^'^- t^iiver picralc and methyl iodide yk-ld the 

methyl ether; thia has the properties of an ester, being saponified 
by boiling with concentrated caustic alkalis, an<l yielding picrainide 
on treatim-nt with ammonia. Thcte faets afftird further evidence 
of the renmrkable increase in tlie reactivity of the hydroxyl-group, 
due io the preseui-e uf tho three nitro-groups. 

I*icric acid yiirUls well-tlefmed crystalline sails, of a yellow or red 
colour, ivhich arc explosive. The potassium salt diasolvce with 
difficulty in water, and the ammonium salt explodes by percussion, 
although the acid it.solf doe.s not. 

Picric arid yields moleculaT compounds with many aramatie 
hydrocarbons; for example, with naphthalene a compound uf the 



MTROPHENOLS AND AMtNOPHENOLS. 



4*9 



formula C,(,H,C,H,(NO,),OH. These rryataliizc w-cU, and aitj 
winietime? employed with advantage in the »'paratUm of hyilro- 
carbtms. or in their idfntifitration by means of the nicltiag-points 
of thesp fumpnumls. Pk'ric acid is readily (.'UmtimlHl from tbem 
by the actiiin tif aiiimunia. 

I'imr- arid can be ttsttd for with an atjueoiis solution t>f polas- 
sium cyanide, which yields a red colouration due )o the funnution 

I of isttpurpuric acid. 

Picric acid Is cmpKiycd as an explosive, usually in the fnrm of its 
animoniuni salt, which ienvos nt> residue on explosion, and is a eon- 

^Blitucnt of ■■ lyddite.** It Is ako used as a dye, imparting a jxllow 

, colour to wool and silk. 

Slyphnic acid, C,H;v,,,'?, is a Ivw of a nitrated dihytlroxy- 

bcnaone. and is obtiuited by the action of rxild nitric aeid upoh 
rcsorciiiol, as well as from wfrtaln gum-rej«ns by the same meaiis. 
The conversion of ni-nitrophenol into styphnic acid by the action 
of nitric acid is a remarkable reaction, the formation of a liydroxyl- 
group taking place simultaneouely with the nitration. 



AmiDopheaalt, 

841. Aininophciiols are foniial by the reduction of nitrophenols. 
TIic acidic character in these compounds is so weakcnrd that tliey 
do not combine with bases; on the other hand, tliry yield salts with 
acids. In tile freo state the aminophcnolfi arc colourless eoUds, 
crj-stallizing in leaflets, and readily Himed brown by atmospheric 
oxidalinn uith formation of a resin. Their hydroelilorides anj 
more stable. 

a-Ami7iaphenol yields compounds by the substitution of acid- 
rcaiducs in the amido-proup; tlicsc at once split off water. They 
toe cb1Ic<1 ankydro-bascB : 



^|6"C-H, 



'0 



li 



AcMyl-drrlrikil*« 




:.CH,. 



8Ui» Dj lainliwp aaaoU 
Aiitiydro bAM 



On treatment with acids, amiaspheaol and acetic acid are regen- 
erated. , 



<Sb. 



--T — 



•430 



ORGANIC CHEMISTRY. 



^■Am-nojihenal is obtained by the cl«etro-roduciion of iutrt>-^ 
benzene in acid solution (293) . 

Tlw alkaliue sotiitimi of p-mni nopheuot rapidly MqiottW ft 
colour uulese sodium sulphite is present. This solution la Mid 
the namo " rbodinal," and ia used as a pbotagraphic developer. 

LuuiiRF. U»8dJacoTered c«rtfiiu ^ueralcooditions which aroHMtia, 
corupoiiiids must fulfil lo ^« iiTail.iWe ag phologntphic developot 
Tliey must eithtr contoifi Mnw* pydroxyl-gronps or AmJdo-jn^>aiH. or 
at least one of eacli. In order ttiat the deraloping action ma)- not b« 
interfered with \vlien subsiituenis are pTesent in the amido group ad 
In llie hj(]roiyt-)[roiip, luit lew* than two such UDSubsiittited gTOupa"* 
must bo present in the molecule. 

A dcriTailrG of p^minophenol used in medicine is phenaixtin oc 

atvti/lp/ienetlfUnf, ^t^i<.Kif ^ nrt' **>* ncutamino-d*rivatiT» of 

pheiietole. C,n,-OC,l!t. 

SullA of I: Q:4-rliftminf>i>hi>nol ar« cmploj-«d as photographic de- 
TclopvRs uuder t}i« namo "amidol." 

Monohy droxy-acld*. 

343. The most important of tiic monohydroxy-acida Is 

OH 1 

o-hyiiroxy benzoic acid, or aalicylU acid, ^ii^^t'^cOQVf 2* '* 

derives its name from salicin, a gliicosidc in the bark and leaves of 
the willow (jw/ii); on hydmlj-Ms, this substance splits up into 
aaligfmin andgluooRc: 

C„H„0, + H,0 = C,H,0, + C,H„0^ 

Wllcia SslleralD Ulnuuva 

Saligcnin U the almhol rorroBpnnding to salicylic acid, into vhieh 
it is converted by oxidation: 

Snllicoiiiu Sallcy Ik acid 

Salicylic acid \s present as methyl ester in oil of winter-green 
(Guaithfrta profunifcens) , from which the acit.1 is still obtained for 
plianiiaceutical U)«e. It can also be prepared by the action of 
nitrous acid on anthraniHc acid.o-aminolienzoTc acid (351), by fus- 
ing (^^hlorobenzoic or o-broniobenzoic acid with caustic potash, and 
by other nictliods. 

Salicylic acid in mantifactured by a process discovered by Kolbg, 
In nhicb sodium phenoxide is licatcd with carbon dioxide in an 



SMUCYuc ^ao. 




autoeUrc at 130°. Sodium phenyl carbonate, CaHj-O— COONa, is 
formed as sui iutcrmediate product, and on beating is converted 
into sodium salicylate: 

C,H»0\a + CO, = CJIe-O-COOPfa; 

^•**»*^t>.CO0Na ~ ^'^^'^OEI 

When COt i« passed over potaasinm phenaxide below 150', sallcylld 
acid ppsulls; but at Ji liiglit-r tetnpemtare, 220*, ^hydroxjfhvmQlc aeid 
U (oniied. Sodium plienozide, on tlie olhor band, yields only salicylic 
acid at 220* . 

Salicylic acid is a white, crystalliiio powder, which dissolves 
with difficulty in cold wnler, niid molts at 159*. When carefully 
healed, it sublimpR, but nii rapid heating sjjlila up into phenol 
and carbon dioxide. With hromiiie-watcT it yiflds a prcoipital© 
of tliL' formula C*ll,nr,'01tr. It gives a violet eolimration with 
ferric chloride, both in aqiirous and alcoholic solution, wiiert^as 
phenol dissolved in alcohol doca not. Wlien hoiltil with calt'ium 
chloride and ammonia, a BoUition of salicylic acid precipitate* basic 

calcium salicylate, CbH,<^ > Ca; this affortls a means of aepa- 

ratitiK salicylic acid from it« isomers, which do not give tlua 
reaction. 

^ftlipylie at'id is a powerful autiseptii', iind is employed a.« a 
preservative for foods and such beverages aa beer. It is not, how- 
ever, completely innocuoua. 

When Ihc acid is lu'sled to 220", it Insr« carbon ditixidc and 
water, with formation of wiicylic phenyl csUt : 






OH 



CO, + H^+C.H,<^So(,^ 



This compound is employed as an ontiaeptic under the name 
"salol." By heating to 300°, its sodium derivative is converted 
into the sodium salt of phenylsalicylic acid: 

"-«"«"^C0OC,Hs ^""'^^COONa- 

iTli« otiAycirfile of salicylic aaid UliroTod try Ilia eryoscopjc d«t«r- 
mlnattoo of ita aolecuUr weight to haro a moloculo of the fnrniuta 




49* 



ORGMNtC CHEMISTRY. 



/(yi,<Q >) ; it 1« i>btiiiii«<l by tbo action ol phosphorus axy- 

•Mortde opon ibe Add. This anliyclride onrstallite) with trro mole- 
•dM«f chloroform, which dm driven off on WNrmiug. Tkia process 
sm lonn ri y as«d in \hv pn.'piini(iou of pure clilororomi. 

S49. Mcta- wid pftra-Ayrfrori/ftmajFc aeiSt j-ield no colouration 
vitK kfTw chloride. Tlioir biuiic barium saite are insoluble. 

FMin ilio fnotibnt tlio niniio«iibsilttition-prodn«U of beoMOc an 
■ok knovii in JHOinerio forms, iho coDdiisioii U drawn that xXm six 
kydro^i ntoiiis or botiKOfio nro of equal value tMS). Tho followiug ia 
a Bun direct proof of tliin cttoality. 

Phitio) in converted bj- tb« aotion of phospboraa bromide into 
IroMobeiiionn, which yicldA bcnEoTo acid when tmttcd witb carboo 
Anxiile and aodiiiiD (108. 4j : 

C,n,-OH — C,n, Br -» a,H,-COOH. 

If the iKttiitoii of tli« hydroxyl -group in ph«nol ia denoted bj- a, the 
pgailion of the «arboxyl-group in the beiuwie ncid obtaii>ed frum it 
Biuil also be denoted by a. 

Tlicro ore three isomeric hydroxy ben sole aciila, all of fchicti can bo 
eonrerted into, or ubl«itiod from, beiuutc acid ; tbwe luay be denoted 
by •;(<, ti:-;, and a:d, a baing the [loaition of (be carboxyl-group. 
and fr, c. and d of tho hydrosji-group. By cllminaiion of CO», nil of 
tli«w yield phenol, proving; that the poaitionx of tho hydrozyl-ffroups 
ar« of equal Tnliic Uoroover, since benxolo ncid is oblaioed rn>Ri 
pb«nol, a mnst bo equal in rnlue lo Iho otb«r three, ao that 
-0 = 6 s a = d. 

It Iiiu slill to )>e proved ib»t tho two remaining positioiu e and / 
are equal in rnUio to tho other four. Tbo staning'polm for thin 
second part of lUii proof is bviizulc acid, the poailion of vrhoao e^r- 
boxfl-group may aKniii bo indicated by a. On brominatloit it yiclda 
a bromobenzolc ticid (Mcfa), which, since it oan bo eonvortcd into a 
hydroxy he nxolc ncid, muai have ita Br^atom either at 6, c. or d. IaI 
it be arbitrarily aasunied th.u it ia niiualcd ate. On nitration, thl« 
bromobenzolo acid yields two im>nicric hromonitrobeiuoto acids, whose 
iBomeriSDi can evidently only be diit to a dilTereuce in position of tbo 
nilro-group, sinoo. in both, tho carboxyl ia at a, and t)ic Br at c. 

These two bronionitrobetizotc aeida can be so rednood that the 
iiitro-i;roup is converted into an amido-gruup, and the bromioe 
atom roplnoed by hydmgim at ih« aame time. The «anM aminobM- 
zolo acid multa from LfK.')i. This 'is only potalUe vben tbo pasitioaa 
oeoDpied by Ihenitro-^ronpa relative to a are identical. The amino* 
add thus obtained is antbraniltc a<nd (SSI), which ia readily ooowttol 



EQUALITY OF SIX HYDROGEN ATOMS OF BENtEUE. 433 

Into lij-droiybensoie acid (salicylic «cid). It followtt that the ntiro- 
groiip ill one of ihe iaomi'Ttc bromoiiitrobciiEolc MCida is ivt h, c, or d. 
As it was arbitrarilj' aaaumed that tho Bralnm is at c, then (he choice 
lici between h and il ; niippoM) it to be h. 

Thti nitPtvgToup in llie other brornonitrobejiKoTo add eannot l>« 
aiCtuledHt </. since llie ainiiiobotiKurcHclil obtaitivd from it vruiiM tlieu 
bo d : <i, and thortiforc difForcnt from the amino-ncid a : b, just as the 
hydroxybeiizolc acid a : ti dirfcrs from a .b and a :c; nhcrcaa expcri> 
ment provea that the tiro amino-acids are idoiitical. The nitro^group 
In the other bromonilrobcnzoic acid miisl therefore be at e or/; let It 
be arbitrarily supposed to bo at/, and it follows that b =/, 



cn,-oooH- 






•Br c, 

, CH.^coon a 

^ \nO, 6 

/Br c 

^ c.n,f-coou« 

^MO, / 



r n /coon 

^•'^VNa.6=/. 

Auiiinuiilic Mli 



The equiilily of lli« [losition e with th« others U proved simitarly 
Anthraiiilic acid (a : fr=/) is converted into hydroxybcnzoic (sivlicyiic) 
acid, which on nitnilioii yields two JBomerio nitrosniioylic acids, whoee 
hydroxy! cim be ^xohaogud for liydroKtMi by a pruccita wlitoh uc^ not 
be dmtcrll)ed here. Itoth ylnld the %an\t. nil roh^riKoTc acid, from winch 
follows ibc cqiiivaluncL- rclntivu to a of Ibo two positions occupicKl by 
the uitrO'groups iu the iBomeni. One of these positioni is c. since on 
redactioo this nitrobcnsolc acid yields fM-aiDioobenKolc acid, which 
cat] be converted into the above-tnentlonnd iicbromohertEoTc add a : c. 
Tie nitro-gronp in Ihs other nilrosnllcylio acid cannot be in th« posi- 
tion 6 = /, Hs the niLmlKiiiujlc B«i<] obtained fmm it dcjcs not yield 
anthmnilic acid on reduction; position d ii also oxclndcd, since it 
would not allow the Iwo uiiro!*enzoio acids lo he identical. There 
remains therefore only the poeilion «, from wbieh it fotlowa that 
c = e. Hence, a =:t = c = d = e =/: 



Aultiraiillic adil 



COOH « 
on b=/ 



<i 



\no, r -^ 
/CO0!I a N 
C,H.^OIt b=/ 

NnO, e 

ISMueric bilroMli«]'lic ftOidl 



/COOH a 

^'"'\N0. c = t 
Kltrabeamtc acU 



4iBtnol>oDsotG Mid 




434 



ORGANIC CHEMISTRY. 



Bfhydrozy-acids. 



y€OOH 1 



344, Among thcs^, protocaUchuic add, CgE^Oll 3, may 

NOH 4 

be mentioned. It is obtained from many reana by fusion with 
potash, and sj-ntheticoJIy by h<^ating catechol with ammoniunijj 
carbonate, the Intttr mcthiid being a striking cxampie of (ho rwwli-' 
ness with which the carboxyl-groiip can eumetiniGS be inlrodueed 
into the ring. It Is easily soluble in n-ater; it reduces an ammoo-j 
iacal xilvrr solution but nut an alkaline copper one. It gives 
characterwtic reaction with ferric chloride, yielding a KTcen colour,] 
which rliangcs to blue and finally to red, on ftddition of a very 
dilute BolutioQ of sodium carbonate. 



It 



Trihydroxy-ftfiidf. 

,COOH I 
/oh ^ 

346. The best known of these is gallic add, C,H,^ , j{J J. 

OU 5 

is ft constituent of g^U-nuts, tea, and dim-diri, a material used in 
tanning. It is usually prepared by boiling tannin with dilute 
acids. It cryFtlatl izi>» in fin<> needier, readily soluble in hotwater.i 
It was mentioned in 314 that the acid loses CO, on heating, fcnrn-' 
ing p>TogaiIol. Gallic acid rrducra the italts of Kold and silver, and 
gives a hluiBh-black precipitate with ferric chloride. In alkali 
Bolution it is turned brown in the air by oxidation, in the same way 
as pyrogallol, 

GnlllG Hold in uKed in the maDufacluro of b)u»-b]ack iiik. For Ifala 
purpoM iu n(|U«ouB aolulion is oiixod with a aoluliou of ferrous sa\- • 
p]i%t« conCalnltig a traceof free Kiilpliunc acid. Without llio acid, i 
forroua sulpliutc nuuld quickly oxidize iu tho air, giving a tbiclc, blnck 
jirvcipilntu witli the gnllic acid; Ibts oxidHtioD isrelartled iu k n-maik- 
able mnuncr by the addition of a very amaU qiiantit)' of su}phiii 
acid. Ax sood us tliu solution is broujiht into contact with paper, tbe^ 
free acid is neutralized by tho alumina always preasnt in the lattef, 
anil, Its oxidation is no loiigor pnivenicd, llic wriiing In drying tarns 
deep-blaclc. As the mixture of the aolntions of ferroua sulphate and 
gallic acid hn_s only a faint browii colour, which would make the fr 
writing nlmoRt invisible, indigo^nrmine is added to tbe mixture, Thi 
Imparts lo the ink coming from the iwu n darV-bluo colour, whkb 
cbangos by the abore-mentlonod process to a deep black. 



Ty4NNlNS. 



43S 






The tannins, ot tannic ociclB. an verj' closely related to gallics acid, 
and are widely distriliiited in tht vegetaMp kiiigdotn. The tannitis 
are coiniiounds which htl- wilubk- in wdtc-r, have a bittt-r, astringent 
taste, yield a dark'bluc or green prenipitate with fviric Kalt«, con- 
vert substances cfniiaining gelatine— such as animal hides— into 
leather, and precipitate albumiaB from their solutions. Some of 
the tannins are plucnades. 

The most typical tanning-material is tanniv or tannie anil, con- 
tained in oak-bark. It is a derivative of gallic acid, into wliii-h it is 
vcrtejd by boiling with dilute hydrochloric acid. Taonin is 
optically aetivc, and seems to have a somewhat complicated molee- 
ular structure. 

It is best obtained from gall-nuts — jiatholo^cal excrescences on 
the leaves and branches rif tlie oak, raiiKed liy an insect. Turkish 
gall-nutit are esperially rich in tannin, ^nekliiig &s much as 65 jkt 
i«cut. 

TAnnln ImpurtaiUtchariLcterUtiQ bEtt«rtAstc to many t>OT«nLgct— to 
tua nhii'Ii lias been too luniu; hifuBtKl, for inKlaiice. Tlie iidditiou of 
milk romoTrs this hitlcf Imio, b««ause the IhiiDin forms na in«olublo 
oumpouiitl wilh tbo nlbumin pnacnt in Ihc milk. 

Tannin is a white (somctimea yellowish), amorphous powder 
ily soluble in ^vater, only slightly in alcohol, and insoluble in 
her. It forms salts with two equivalents of the metals, ami pre- 
icipitales many alkaloids, such as strychnine and quinine, from 
.heir atiiieouB solutions (401). 

A liistinction is drawn between the difTerent kiods of tatuiing- 

|sul>fi1ance8, which have properties analogous to those of tannin, but 

iffcr from it in composition. They are named after the planta in 

hich they are found; kino-tannin, cateehu-iannin, moringa-lannin, 

coffte-iannin, oak-tatinin, quinine-tannin, and others are known. 

S46l The taunins aroiis«cl in fM-didaa Hni In tlia tanmnt/ nf hida. 

Id miikiag leather, tbo hidu is naturatiMl vritli tliti tnaaiD, bocaiisa 
wiUiout this treattoenC It cannot b« usi-il in lliv mauufmotur« of shoes, 
etc., ftince it soou dries to a biiri]. honi-iiko substance, or in the luoiai 
condiitou becomes rollun When saturated wilh tauniu it lemnins 
pliant, aud docs aot docomiKisc. 

The skin of nu animal coDsisIs of thrtw Utycrs. the epidermis, tba 
cuticle, «ud the fatty-layer. The cuticle being I he part mttdc im* 
leaOiiT. the two oilier layers arc removed b; susi^nding (li« hides ia 
running «at«r, ahea th« epidermis and fatly layer iH^m to devom- 



43* ORGANIC CHEMISTRY. 

pose. And lire ouUf removed by meAns of a blunt knife. AlteniAte 
horiEoatal la>'9n of tbe hides thus prt-pared and oak-bark or sonw 
other matonal coataining lantiin Are plAced in l&ri:^ troughs or ¥«(<(, 
wbich are ihen fllled with water. At the end of six or eight w< 
the hi(l«a arc tnkeii out and pl&ccd in a aecond Tat cootjiinlog freih* 
bark of utrougcr qiuilily. This ii contiuuecl nllh increaAin^lf ooowa- 
trAled tADDlD-solutiotu tintil tbo bidM aro porfeetl; tftQD«d, tb« proceat 
lasting ta long as two nr three years, Accordiog to the thictnt^i of ihe'l 
hide. Whelher a hide is tborougbly utnrated or tAOticd maf be 
Judged from ih« appi-anince of iis cnM»«eclloii, or by trentmcnl wiih 
dilut« Acetic acid ; if this ttoatmetit tDAkcs ft awt^ll up InlcriiAlly, It 
shows that the conirersion into Irathcr is incomplete. It is still a, 
natter of doubt whether lanniof; is a tnecbanioAl or a ehemrcal proMMvl 
According Co some, lh« Uimln U .'*imi>ly de]Mniied mechanically in the 
t)id<M ; Recording to others, ehctnicnl union takes pUco lielweom the 
tissue of the hide and the tanaio. The first view it hold by Dioot 
chemists. 



Acids CoDtaiaing Hydiroxyl or Carboxyl In the Side-chaios. 
347. Three different types arc here posdWe: 

1. OH in thesitU'-chaiii, COOH in the ring; 

2. COOH ill the sitlc-<hftm, OH in the ring; 

3. OH and COOH IwUi in the fude-chaiii. 

The following are repreaontatives of these three claaees. 

Oil OH I 

1. Htjdroxymcihyllf^TJsoii- acid.CtHt<.,Qka «' "** mentioned 

in 826. It yields phthalide by separation of frat^r, and u 

CH CI 
obtained by UiiliiiK v-X'jlylcnc chloride, C,H,<(-.u*™, with water 

and lead nitrate. 

OH 

2. p-lIydroxyphmylpTvpionic acid, f'i*'4<(:u .riL.mOH ** 

of some inipf)rtance owing to its relation to tyrosine (M.P. 235") — 
which derives its nanie from its presence in old cheese, and is pro- 
duced when alljiniiiiis, such as. thf> white of ogg. hom, hair, etc, 
are boiled witti hydrochloric or sulphuric aeid. Ite formula 

Al 
UC,H„NO„andils slnicluro HOC,H..CH,.C^OOH; it is 

a-unino'acid correaponding to p-hydro.x>'phenylpropiooic acid. 



HYDROXYCINNAMfC AND MASDEUC ACIDS. 437 

fan amino^vid. tl yields salts with acids as well as with 

OH 
i>//3«lh»iyanmimK:an'rf,CflIl4<f^tj.pTT.pQj^tT, exists in two 

forms, cumaiic add and cunuirinic add, which art; easily converted 
into cufh titiitr. Cumarinic uciii is nnt known in the free slate, 
but only in the fonn of aalt^, siiw.K it iil nnre la^irH a inolnculc of 
water when set free, yielding cumarin, the arcmialic principle of 
wood-ruff {Aipenda odomla). Cimiaric acid, on the other hand, 
does not yield a corresponding anhydride; reniuvn! of water pro- 
duct* cumarin. wliith is converted into salt* of cuniarinin acid l>j 
treatment with alkalis. This behaviour recalls llial of fiiniaric 
and inalei'c acids (170), and it may be assumed that this is a similar 
east of stereoisomerism. Both acids may Uitn be represented as 
follows; 



H-CC,H,-OH H-C-C.H,-OH 

II -H,0 

H-u-a "" 



HOOC-C-H 



■COOH 



ti< 



CmnarUaciiI: 
«• naoorrHHiNHidfPic 
•■ilifdrlilw 



Ciimnirliilc acid: 

only knirwii 111 llir torin 



H-CC.H, 

II >o. 
H-COO 

Cuinai'tu 



Cumarin can he obtained from 
oynihesis (309): acetylcumaric acid, C„II,< 



9alicylaldehyd« by Perkin's 
0|C,H,0 



is first 



■CH:CH-COOIH' 
formed, and is converted into cumarin by healing, acetie acid being 
split n(T, 

3. Mandelic acid lias both hydroxyl and carboxyl iii the side- 
chain. Its coastitulion is CflH,-CHOHCtXJlI, as its synthesis 
frnm heiualdeliyde and hydrocyanic acid indicates. The mandelic 
Acid fiiuiid in nature is Ixvo-rotatory; the s>-nlhellcal acid can be 
split up by the action of eulttires obtained from mildew (PeniaUium 
^aucum), the dextro-rotatory acid being left intact- The decom- 
pOEilion is also effected by the fnrmalion of the einchonine salts, 
when the salt of the dextro-rotatory acid rrystalUies out first. 

Bydrozy-aldehydva. 

8U. These can be obtained artificially by a synthetical method 
generally applicable to the preparation of aromatic hydroxyalde- 
hydes. It cnitsitits in treating the phenols in ethereal solution ivitli 
anhydrous hydrocyanic acid and hydrochloric-add gas, it being 




438 



ORGANIC CHEMISTRY. 



BOinetimes sn advantage to add a small quantity of zinc chloride as 
conilensing-agcnt. This mode of s^'nthcsis was discovered by 
Gattkhmann, whose name it Ijears. The hydrochloride of an 
imide is formed as an iatenncdiate product, and can sometiinea boj 
isolated; 

C,H,OH + HCN + HQ = C,H,<^^^.j^.jj.jjj^ 

On treatjucnt with warm water, the imide-salt is converted mto 
fibc bydroxyaldehyde and ammonium chloride: 

p-Hydroxybmtatdckydc is here obtained from phenol. 

/OH 1 
Salicytaldrhyde, CoHjN^p^Ilo. occurs in volatile oU of spiratL 

The »-hydroxyaldehydc8 colour the skin deep yellow. 

To this class of substanccH beInng3TOnt?/i7i,C«IIjr-0CU|3* ** 

\OH 4 

metli\'l ether of pjiocatechualdoh yde. 1 1 is the aromatic principle of 
vanilla, and is prepared on tlio large scale bv oxidizing igocugenol, 
.Oil 



• C,H,^OCH, lids substance is obtained by boiling fuj^eno/, 

K \CH;CHCH, I 

, with alcoholic potash, which alters the posH 



/OH 

VHj CH:CH, 

tioQ of the double linking in the side-chain. Eugenol is the chief 
coijstiluetit of oil of cloves. 

For conipoumis containing the hydroxyl-tcrtnip and the sulpho- 
group or the hah^gens, (■/.•(oppcctively 333 and 338. 

IT. coHroimis with the mTBo-osour and amido oroqp. 

Nltranlllnei. 

349. These compounds can be obtained by the partial redoe* 
lion of dinitro-compound3 by means of ammonium sulphide. 
Another method for th«ir production consists in the nitration of 



NlTROBENiOIC AND AMfNOBEHZOlC ACIDS. 



439 



anilioee, though if nitric ncid in allowtxi to act directly on this base 
the resulting [jrodunts arp inosUy th(»s«t)f nxidatioti. If nitration 
18 to be carried out, the ainid(»-group inust lie " protected " against 
the aotion of this arid, cither by first converting the aniline into 
acctanilidc, or by causing the nitric &t:'«\ to react in preerncc of a 
large quantity of sulphuric acid. When the acetyl-compound \i 
employed, p-n\(raniHn(r is the chief product, o-n\tTan\linc being 
formed when milphum acid is used. 

In these substances thi^re in a weakening of the basie eliaiacter, 
m-ntfrantTtTur, for example, yielding salts which are decomposed by 
water. 



The 0-, m-, and p-nitranl lines, Cf\\t< \ j^' ^"^ yellow, crystalline 

Their melting-points are 



I 

^Kcorri pounds, readily soluble in alcohol. 
Hiespeotively 71°, 114°, and 147*. 



Kitroheazok Acids. 



350. The mf(a-conipnund is the principal product obtainetl by 
nitrating benzoic acid ; some of the wiAo-acid and a very small quan- 
tity of the parn-aeid arc formed at the same time. The orlho- 
Icompotind !.•; lje.st obtained by the oxidaiiou of ort/io-nitrutoluene, 
and is characterized by an intensely sweet taste. 
The introduction of the uitro-group raust-fi a large increase in the 
Value of the diaaociation cunstant K, which for iH-nznic acid itself 
ie 0006, for o-nitrobcnzoie acid 0-616, for the m-acid 0-0345, and 
for the p-flcid 0-0396. 'I"hc melting-points of these acids are respec- 
tively 148^ 141^ and 241°. 



I 



Aminobe azoic Acids. 

3&1. The most important of these is the o-acid, called anlkranUic 
oeiti, first obtained l>y the oxidation of indigo. It hft.s quite the 
charaetcr of an uinino-ncid, yielding KaltK with both arids and bases. 
It possesses a sweet taste, and slightly anlLseptic prnpertles. It is 
obtained by the method of IIimjcikwf.rfk and va.n I>irp (244). by 
treating phthalimide with bromine and raufllic potash; the potas- 
sum salt of phthalaminic aeid is fir^t formed, and then changes into 
anthranilicacid: 



ORGANIC CHEMtSTRY. 



C^<gg>NH 

MiltuJiinJdB 



-* ^•"i< COOK •^ ^ ''' wi 

PaUiHluRi fiJktbmluitlukte 



t\X)H* 



jAnthranilie acid melU at 146*, and can be sublimGd witliout 
composition; it is readily soluble iii water ajid in alcohol. By the 
Ithod given above It is prepared technically for the synthesis of 
fSgo, bteachiug-powder being substituted for the caustic potash 
it bro[uino< 




0RI25TAn01I OF AAOUATIG COUFOTnTOS. 



303. Orientation is the dctcnni nation ot thn positions wKich 
the side-chains iir stilwtitufiita in tlic bcnzcnc^ring occupy in- 
relation to one another. A dcsi'riptiori of a number of the most 
important eubstitutod bcuzcne derivatives having been given in 
the foreg()iti(; paries, it bcconit>s necessary to funiiah an insight into 
tliG mL'thiidg hj' whieh orientation is carried out. 

These rest on two tniiin principles. 

1. Heiative lirlmiti'italitm aj pasUian. — Thv compound, the posi- 
tion of whose siiiKitituentt) is unknown, is converteil into another 
with known positions; from this it is inferred that the first com- 
pound has its siibstiluenLs tirraiiK'H) .•^iniitarly tu the si-eond. If, 
for e.vaniple, Uie eonslitulion of one of the three xylenes is rectuired, 
the hydroearboQ can be oxidized; the particular phlhalie acid 
formed indicoU"s the positions of the methyl-groups i» the xylene 
uud(;r exaininulion, |>rovided the positions of the carboxyl-groujis in 
the three phthalic acids are known. 

In order to apply thw methnd, it is ncceswar)' to know the posi- 
tion.'t of the .lulistituenlH in a atiuil) nunil>er of rompounds, and it 
is further a-tsiinied that the ptmitionK of the Kubstituent!) remain 
the same cluriiig Xhv nnirsc of the rractioii.'* which have to be 
mafle use of. ICxprriencc has shown tliat this is true in most 
caBce, although the poation of the uide^hain dcK's alter in a few 
reactions. 

It WAS «(at«d In S8SI thftt the throo bnnuMiulpIianle aeljt an ,$oa- 

Tcrtet) into Rsorcinul by fusiuH nilli cuiietio [xitiub, Thers SM tfStsr 
exanplea of cliiingc of position wbrii llic «iil(ilio-group is replftccd hj 
the hydroijl group, hj fu&ton with caualic nlkslis. 

In order to avoid erroneous conchiwons, it is. therefore, desirable 
in casts of doubt to check the determination of position by convert- 
ing the substance into another coinpcnind. 

2. Abatiute deirrmination o} pustlion. — Thia is the detennina- 
tioo of the pa>utions of the subKlltueuts without having recourse 
to other compuimds tlic positions of whose subatituents arc 



ORGANIC CHEMISTRY. 



knows. A general method is afTtyrdcHl by Kornes's principle, by 
which it ie possible to ascertain whelher subslances C^H^X,, con- 
(aiuuig two 8ub«titii(.'iit8,are ortho-, meta-, ur par(iH:uii)iKiuiulK; this 
is Kffei-twl by ik-tennining the number of trisubstilution-productg 
c«.>rTv»poiuliiig to them. 

Whrd a tliinl gniup, Y, ifl introdufied into an ortho-compound, 
r,H,\,. whether Y is the same tis or different from X, only (wo 
tt>oiiK>ni CM) be formed, 

X X 

and 





the IntmdiicUoii o( a tlurd group into a mWu-compound renders 
(hoaibli' llir furnmtioii of ^wee isomers, 

XX X 




JX' "^ T 



(>• 



in the case of n para-cninpoiind the introduction of a third 
Ipyiclda only otic triaub»tituti«n-|irx"lijct, 

X 

1Y 



In addition to this getieral niethnd, there are others for special 
own), several of which nmy be mentioned here; it will be obecn-cd 
ijiat they fully subiitantiate the conclusions already arrived at by 
K0llNCR*6 nielhod. 

1. AbMlute determiaation of poBitioo for or/Ao-coiopounda. 

353. For the orthoser'wB, the strocture of a dibromobensene 

inielting at - P is tletemiined by means of Kobkeh's principle; this 

'body yields two isomeric nitrodibromobeuzenee. The constitu- 

Uon of a xylene boiling at 143** and melting at —26", has also 

been established by this method; it gives nx to tn-o isomeric 



OIUENTATION OF AROMATIC COMPOUNDS, 



443 



nltroxylenes when treated with nitric acid. This xylene is con- 
verted into pbthalic acid by oxidation, showing ttiat the latter is 
an ortAo-compound. 

That the carboxyl-groups of this acid are in the ortAo-position 
was also determined by a different method, by means of the 
oxidation of naphthalene, C,jHg, a hydrocarbon which is con- 
verted into phthalic acid by this treatment. This fact showa 
that its structure must be CoH^ < C<H^, in which the group C^H^ is 
linked to two positions in the benzene-ring. When naphthalene is 
treated with nitric acid, nitronaphthalene is formed, and is con- 
verted by oxidation into nitrophthalie acid. The group C^H^ has, 
therefore, been converted into two carboxyl-groupp in this case also; 

NO.-C,H,<C.H<-* NO,-C,H,<gggg. 



HltronaphtbAiene 



NlCrophthallc acid 



If, however, the nitro-group is reduced, and the aminonaphthalene 
thus obtained oxidized, phthalic acid is formed. Hence, it follows 
that the group CjH^ forms a second benzene-ring with the two car- 
bon atoms of the benzene-ring, so that naphthalene must be repre- 
sented thus: 




The oxidatjon of nitronaphthalene and aminonaphthalene is 
expressed as follows ; 

/\C00H 




COOH 



XO, 



and 







HOOC/^ 
HOOcl^ 



ORGANIC CHEMISTRY. 



This shows that phthalic acid murt be an orMo-compound, because 
if it be BESurD«d to have the mna-structurp, for example, tiaphttia- 



lene must be ro)>n«eiit«l by the formula 




. which leads 



at once to a contradiction, sinre there cnuld not thpn he a benzene 
derivative prodiired by the oxidation of both uitruiiaphtliak-De and I 
aiui noriBphlhalenc. 

2. Abiolate dct«nDiDation of potitios for m/-(<i-ooinponodB. 

354. The proof that mesitylcne is s>'mnictrical trimethylbonzenc 
(1:3:5) isstated by I^dknburo as follows. 

H 

If this compound has the eoostitution )|| Ju *< ^^ thre« 

CH, 

hydrogen atoms dirpctly linked to the benzene-ring must be of 
equal value. If this can Im* proved, the stnictun- of mesitylene b 
established. 

The proof of the equality ia na foUowa. On nitratiag mesiljlene a 
dlBltKMXXnpoiincI is obtaioetL If the hydrocarbon ia represeowd to; 

I. C,(CH»>,HHU, 
the dinitro-compAuud ma; be arbitrarilj nssumed to be 

One of thenitro-KTOu}»sof ihedioiiro-«oinpoand in nKluecd.andih* 
reaultiiis fimfno-orepound ia oonrfrricd ioio an acvlyl derivative i 
luppocu! that Ihu acnt)'t><Ieriv8Uve ia 

III. (.VC'U,),NO,NU(C,H,0)H. 

This )ut»tanc« can bo A|caln ottnit<td. wrjien then must result 

c;(Ci!,i,Nb,!rmc,n,oiNb,. 

It is possible to eliminale the acHylamido-gronp. NU(C1T,0). froa 
tblit uvmpounit by sapoiiiflrntion, Riibi«qu«nt diazotisatioo, et& la 
this irajr a dinitromoaltjli^ne wiih ibo formula 



ORiENT^TtON OF AROMATIC COMPOUNDS. 



445 



ined, And U tound to be id«nticttl with ch« former dtnitro-pro- 
duct,th« nitro-groups q( wbic'ii Araataandfr. Frotnthiiitfolloiri ihnt 

a" = H'. 
NitroEDflsidl ne, a :h. whose Roelyl^compound Is rspreMntfrd by for- 
malA III, furnishes a further proof chat II' = II'. 

When tliD ainidosiroup \» etimitiated from this by meaas of the 
dia2a-r«ne(ion, there is formed 

tV. CVCn,),NO,HH. 
Tliis is reduced and convened inUi an iic«tyUcoRi pound, ocotj']- 
meftidine. 

C!,(cn.),wii<c,n,o)HH. 

This compMHid can bo again nilrati-d, yielding 

0,(Cfl,SNn(C,TI,0>NO,U, 
it) whioh it is of no coiiaeqiiAiice whmhvr liiv nitro-gronp is ia ths 
poBition h or c, sinco (lie equality of these poaitioiia I'olatira to a has 
been already proved. 

Oil vliiuiiiatinK the acelylrunido-KToup from tbe sukstanci! lut ob- 
. talne<]. -t Rjotionltmmeiiirylvnr ts produced. Identical willi t ho cumpound 
IV; it Tollows that «=&=(■, which cooipktce tho proof of the 
Mjiiality of the threw hydrogen aiunis. 
From the known «tn.siitution of mesitylene it is possible lo 
deduce the stnidvirr of niany ottier compounds. For exariiple, 

/COOH 
jwrtial oxidation converts it into mtsitylenic acid, C,H,;--CH, , 

which is in turn converted into xylene by distillation witli limi;; 
this compound mnst be iwcfa-xylene. Oxidation converts this 
m-xyleiie into isophthalic iicid, shnwing that the cartx)xyl-group3 
in the latter occupy Uic Tm'^a-pusition, These determinations of 
positiun tiavc! been fully substantiated by the application of 
KCiLNKii's. principle. Thus. NijLTlNo lias prepaatl three isomeric 
nitnixylenw. in which the relative positions of the iiicthyl-groupa 
are the same as in the xylene obtained from mceJtyleuic acid. 

Among other mrfa-eoinpounds in which the position of the 
j;roupi> has been independently cstahlished, there may be men- 
tioned a dibromolienzene boiling at 2211*. K6hnkk proved that 
corrpsiHindinjit to thi--! substaiire are three isomeric tribromobenz- 
enes and thn-c nilrfHlibntjiLiiben;:enes. In ronclusion, it may he 
mentioned that tho phenylenediamine which melta at 62*" can be 
obtained from three different diiiminobcnzolc acids by eliminalion 
of CO„ 80 that it also must be a fnrfa-comDound. 



44« 



ORGMHIC aiEMISTRY. 



3. Absolattt determination of poiition for para-c«mpound». 

355. KOrner's principie has bwn of gn?Bt sorx'ice in determining 
the const i tut inn of some members nf ih*- ;xim-scries. For example- 
from the sylene boiling at 13S°. an<i melting at 1.1*. it was only 
possible to obtain one mtroxylene; the- phenylenetliaminc meltinK 
at l-K)" can only be obtaioed from oii« diaminobctuolo acid by 
splitting off CO,; ete. 

These del4>rniiriAtion5 of jMiaitJim have hern cunSmuKl in an- 
other way. Thiis, a hydn>xybeiizoTe acnd melting at 2l(I* ha»i 
Iicoti proved to have the jwra-croiistilntinii. It is obtaint^l from n 
bnMnobnizoi i: acid, which can !«■ got fnim nnJiiiary bromotoliimr. 
the latter IwiiiK convert il»h; into a xylene from which tcrephthiilic 
acid can be ohialned by oxidation. ;>- Hydroxy benzoic acid affords, 
therefore, a valuable basis for orientation. 

The proof can bo Klalinl as follows. The start inp-point is bromo- 
benxoic acid, obtained dirr-rtly by the Imimiiiation of benzoiV aeid. 
Oil nitration, two ianmeric tiitrobromobenwi'c acids arc fonoed, 
either of which yield* on reducticm the same aniinobenzoic acid 
antbranilic acid; this can be converted iittii Nklicylic aeid by itieai 
of the diaxo-reaction. It follows that in lH>th the isomers Ihf niiro- 
gnnip must bo Hituatrd syniniPlrieHlly to the rarboxyl-group: nt 
2 or fl, or at .1 or ft, if thf earboxyl-p otip is at 1 . The same reason- 
injK (•stablisht'S tin- posittmi of the hyilnixyl-ftnmp in salicytir acid. 
CuncrmiiiK the pcwiliun of the bronune atom, it ik evident that it 
cannot be at 4, Wcautir tw<> iwinicric tiilrtK'om|M)undi) whieh woiiid 
yield the samo aininobcDzoio acid, ou nxluction, could ant be 

;«bt*ined from Br/^ yCOOH, The bromine atom, must, thrny 

iore, occupy the w/u-potatioti or "fMo-iw'sition to the cnrboxyl- 
group. A hydroxybeiuoic acid tucUinK at 2U0*, obtained by tliiis 
meaiLt,- must thpjpfore be meta nrortho. Since Uie Isomeric mlieylic 
.aeid ean al.so be only » mf/o-rniiipoiind or an or(/t»-rompound, 
there remains nn possibility, except the para -structure, for the third 
Jiydroxylwaizoic acid rnel I ing at 210*. 

Detennin&tioa of position for the Trisubatituted and higber- 
tabstitnted derivatives. 

aS6. This can u-sually bo efTi-ited by a»M?ertainirig the relation in 
which they stand to the diderivatives of known coufctitutioa. Fur 




ORIEHTATtON OF AROMATIC COMPOUNDS- 



example, since a certain chloronitroaniline, CBlI,a(NO|)(NH,>, 

U obtained by nitratiog m-chloroaiiilme, <^ yCl, and jrields 

■^p^hloronitrobcnzene, NO,Q^ ^Cl, by exehauge of the amide- 

group for bydrogen, it follows that it bos the constitutioo 
NH, 

NO,<f~)>Gt. 

A more oonipticaled ciample of orientation U afforded bj the way 
In which the posilions of thn groups In pterie acid an> asoenained. 
Careful oiiraiion coavertd [ibcuul into tiro nioaonttropbeaolai 




OH 



0" 



and 



M.P. «' 



M.P. 114' 



Om of tlicw must be the ortAo-compound and the other tbo 
para-iiompounA, txicxiise iha ibird nicroplienol caa be obtainiK] twia 
w-dinilrobcnwjiw— the oi>n«titutlon of vhich \iM been proTwl by 
il8 reduction to rii-phcuylt^nvdiutuinc i8M)— by reduclion to mcUt- 
nitraniline, and subsequent Mchntigi* of Nil, for OH by dluolizing. 

When further nitratcil, both DitraplicDob yield the same dioitro- 
phenol, which can tberetoro only havo tha formula 



\VO, 



ThenioiioDLtrophet]o1.whlchni«luat 114*, iseonrorted byoKidatioa 
into qniiione, and must. (her«fom, be tho ;wra-ooRipni)nd, For tha 
body melting at 4A* thcro n^miuns onlj' iho orilto-ttr\icl\m. On 
nilrntioti tliia o-nJtrophcnol yieldt, in addition to the 1 :3 :4-()ini- 
Iraplictiol (OU at 1), another dtnitropbcnol wtlh Ita groupa at 1 : 2 : 6, 
OH 

i ,y jNOij f^p p,j conversion of this ieto iu melhyl ether, and heat- 



448 



ORGANIC CHEMISTRY. 



ing the bitter with &looholl« unmonift, the {^up OCHi is repUc«(l bj 

NH,;»ndthteiab»lAno«, which lia» the fonnuU'^O*! 1^^*, U »a- 

Tert«<l bj' tho sabstitutioD of bydrogen for the NEIi-groap into ibo 
ordinal*)-, or meta-, dinitrobsnzeae. Tliiu. ve h&ye two diaitropbeBois 
of kuowQ Btrueture, 

OH OH 

NO./\lTO, 
and I J • 

10, 

Further nitrittion conrens both of thQS«> into picric add, vhidi mtuC, 
tlienforo, hare tho cooatitution 

OH 



lifo. 



wo. 



From the known conitltnllon of picric acid maf bo iaferred the 
posiliun uf Ihu groups in ordinary Irinitrobonzcno, since Itiia com- 
poiiiKl ia Tf^julily oiidiKil to picric noid (3111. This lrinitrob(>Tizeii« 
must, accordingly, hare th« aymniotricjil »lructure. 

lafluenoa of the snbstituenta oa each other. 
367. This influpnce is vpr}' irnportJint, and manifests ttself in 
varioiiB ways. It airpcls the ptiisiiion which the Biibtititumts 
take up in relation to om* another, when introrluced Rimiiitancotisly 
or in succetwion into thc^ IvnzrnoniicleuN. \.cX us ctmsukT 6rst 
the fiiniplrst ra.sc, thp introilticticin of a srcond atom or grmip into a 
mono5iil>slitiitr(l conipnuii<I CHgX. It js fmind that one of the 
three possible isomers is always obtained as the chief product, the 
second isomer being prodiicpd in less quantity, while the yield of the 
tlurd isnjiiiiT is very uiiall. For example, when beiiwjie acid is 
nitrated at 0'*, SO-2 p«-ceut. of mela-, 18-5 p*>r cent, of ortho-, and 
only 1-3 per ci?nt. of pam-nilrobenitoic acid an? formed. On nitra- 
tion at30°,mlrobL'D«unf yii-lds 90-9 p<'r reui. of the mtia-fS-l per 
cent, of the orlho-, and 1 per cent, of th(^ para-compaaad. It has 
often been stated that the introduction of a second group resulis in 
the formation of only one or two isomers; but wbea a eticfol 
examination lias been made w to the presence of the third isonwr, 
it has been shown to be present in minute quantity; so that it is 



45« 



ORGANIC CHEMISTRY. 



OrtAo-groupflsomclimwexcrt a remarkable influence in rEiarding 
or iMUtially prevuiiling reaclioris which otherwise take place readily. 
Amongnthera which have been observed, thefulhiwingare examp!«i. 

It is known thai when un a('i<l \» disKolvcil in cxcetiS of alx<(>luto 
alcohol it can br alniont c|uaiitibativcty cnnvrrtixl into an 
ester by parsing through it a current of hydrochloric-acid pas (99j. 
Victor Mbysr and his pupils found, however, that eeterifica- 
tion of acids containuig two groups in the ortAo-positJon relative 
COOH 

to carboxyl, Xf ^X, was by no raeana complete when carried out 



in this manoer. On the other hand, when the acid has been con- 
verted into an cater (by means of the alver salt and an alkyl halido) 
the ester so formed can only bo saponifioil with great dHRctilty. 
When th« two substitiientii occupy any of the other potiitians, 
those peculiarities do not manifest themselves, or at least not 
^ to the samrextent. Ketnnes substituted tn the two ortAo-poa- 
CH. 

Mam, <C "^CO'll, where H is lui Hlkyl-radicle, cannot be can- 

into oximes, wherein thev differ from all other ketones 
CH, 

(Ka-Uiniethylatiiline,<f ^NH„isnot converted by treatment with 

CH, 
an alkyl iodide into a quaternary base; pen tamothylbenjconi trite, 
C^CH,),CN, cannot be saponified to the corresponding acid; the 

/NO, 2 
melliyl-hvdmgBn in o-o-dinitnitolueiie, Cfln,^CM, 1, rannot be 

\N0, 6 
rcplaretl by halogens even at a high teniperatutie (200*) ; this is also 
true of l:2:4-dinitrotohiene; Auwt;rw and Jamieson Walkkr were 
unable, in spite of Qumcrous attempts, to effect the hydrolysis of 

OH 

o-uitroiaUc>'Uc nitrile, f ^CN , to Oic corresponding acW, 
OH 



INFLUENCE OF THE SUBSTITUENTS ON EACH OTHER. 45' 

Groups occupying positions further removed sometimes exert 
a similar effect. One of the NOj-groups of symmetrical trinitro- 
benzene is easily replaced by OCH, through the action of sodium 

NO, 
methoxide, but for trinitrotoluene, NOj<^ yCH,, this is not 

NO, 
found possible: the methyl-group prevents exchange of the nitro- 
group even in the para^position. 




TERPEI7ES AND CAMFAOBS. 



358. Atl the toqipups h»vo the cmpiripal composition C,H„, but 
most of lliosf which have i)eeii exflmined have the moloeiilar for- 
mula CjftH,«. The true terpeiics. C,oH,,, will Lhercfore lie (iescribed 
here, ami the Hemi-tirpcnes. C»H,. as well aa the poly-ttrpena, 
(C»HJx, left almost oulof iiccouni. 

Most camphors have the fornmlft C|oH,,0, but Boroc varieties 
of the formulip r,„II„OainlC,„IIj^<>ftre known. 

Both the terpeiips ami camphors, which are nearly relate*! to 
one another, arn widnly rlistrihutrd throughnijt the vegelablo 
kingdom; the spccirs of Pimis arc particularly rich in terpenes, 
and yk'hi oil of turtjontine, a mixture of thcst- hydnwurbona, n-hcn 
iliittillud with steam. Common or Japan camjjfior. C,pH,/), is 
obtained in the same way from the camphor tree {Ijturus cam- 
fhora) and Hnmeo camphnr or iKirneol, r,oH,,0, fpom Dryohalanopi 
aimphora. Many ethereal oils roiisLst chiefly of compounds C,,H„ 
and C,J!„0. 

The tcrpe nf^ nrc fhjpfly lif]nid>i — verj' few are soUds— which boil 
at temperatures ranpinj; from loH" to 190°. They have a charac- 
teristic 0<lour, are tolerably stable towards alkalis, but are eaailj' 
decomposed on treatment with acids, or on being heated to a high 
teniperamre. Somt* of lliom are oplti-ally atlive. 

The camphors are solid, erystalliae gulwlaiicca, and are very- 
volatile even at ordinary tem|K?rature8. Tliey can be sublimed. 
and arc cliarat'ttTiiied by u peculiar odour. I^)nie varieties are 
optically active. The convertibility by various means of the tcr- 
penc9 and the camphors into arnmatic bodies betrays their relation 
to the latter. Thus, p-t^luic n^cid and lerepluhalic aoid, alonp with 
other compoundn, are rjbtained im oxidizing terpenes with nitric 
acid. In particular they an* related to njmcne; this aromatic hydro- 
caiboa caii be obtaiQcd from the tcq^ciics by the action of Iodine, 

4Sa 



TBftPENES. 



453 



for example, and from camphor by moans of dchydraling-sgcaLs, 
BUch as phosphorus pentoxido : 



C.,H.. 4 I, = ('..H,, + 2H1; C.,H,^J - H,0 

T^rpttfn CyttitiUa Oiiii|)Uor 

Terpsnea. 






SS^. The natural ethereal oils C,o]I,b have difrerent physical and 
chemical properties, acronling to the particular plant from which 
thej- have been obtained. In default of iiielliods by wliich Uw 
isomers cntild be sharply ilistinguishcd from one another, it was 
fomierly supposed that there was a ^teat number of cuiii|>uuiidh 
with the formula C'loH,,. ^V-^u.^cn succeeded in preparing well- 
dcfinod crvKtalhne derivatives of iJie compotrnda C',oH,„ and thus 
in dL>:ting:iiUhin^ the esisting woniors. It was found by this means 
that the niitiiral etheri>al oils are prineipally mixtures of such 
isomers, of which fifteen liave been identified. They Br« claaaified 
into two main gronpfi. 

1. Subfltaiicefl with (he formula C,^H|„ which form addition- 
products with only one molecule of HCl or with two Br-atoms. 

2, SubslanoeKwiih the formula C,,H,„ which form addition-pro- 
ducts with twa innleeuleH of HCl or wilh four Br-Htoins- 

Some particubirs regarding the individual membOTS are given 
below. 

Pinene is the ma«t widdy distributed of all the tcrpenes; it is 
the principal constituent of German and American oil of turpentine. 
Tlic Hrst contains i-hielly a la-vo-rotatory, and the second a dextro- 
rotatory, modification. The boiling-point of this substvtoe is 
ISS^-iei', and its specific gravity nSB-0-89. Wilh nitroayl 
chloride, NOCI. pinene yields nn addiiinn-pmducl. C„H„N'( ►CI, 
froiii which HCl h split off by healing with alcoholic piitaali, 
yielding a compound, Cj^H^NO, niVroaoptnnw. Thb can be 
reduced to a has*-, C,«HuNH,. pinylamiite. whose hydrochloride on 
beating iradily decomposes into aniniunium chloride and cymenp, 
C,«H,4. Pinene unili» with one molecule of HO to forma solid 
crj-stailine mafis, C,„H„C1. meltitiR at )25°; Ihh substance is calhxl 
artificial camplior, and strongly re8eml>tes natural camphor in its 
external appearance and odour. 

On healing artificial camphor, C„H,^1, with anhydrous flodium 
acetate and glacial acetic acid (a general method for splitting off 



454 



ORGANIC CHEMISTRY. 






lw(lroehIi)rif acid from tcrpow? hydrochloride*), there is formed 
mmphene, one of the few fioliil eonijjomiUs Jiaviiip the ooropoailioti 
C,,lij ,. It is cr>-sta.Uine, melus al 30°, and is known both in the 
dtrxlro-rolalon- and lan'o-nitatoo' niotlUication!*; il has an oJmir 
like tuqx'nt inc and ramjiiinr. and is not a natural pnxlurt. Oxida- 
tiim with chniniic acid coiivrrli^ raiiiphcnc itil<» camphor. It is 
likewise obtainable in the rcverBc way from camphor: bomeol is 
convprl<Nl rrio caniplicnc by the spiittiiig off of water. Camphene 
forms an adttiiion-product with otaly one molfculc of HCl, the com- 
pound C,«H,,C] which is formed being isomeric with artificial 
carnplmr. 

360. Among the siibetanntt C„H,a \M>ich add on two molecules 
of HCl arul fuur bromine iUmieJimontru ami dipenlme deserve 
^KCial mcniion. Limoncno is the principal constituent of the 
etliereal oil oblaiiied from oranf;c-rind, and is also present in nu- 
merous other ethereal oils, such as oil of citron, oil of bcTgamot, etc. 
Dipixitene appears to exist as such only in Oieum n'mr. but is 
formiHl by heating limoncne and other Icrpenes lo 250' to 300*. It 
ia. therefore, present in ethereal oils in whose preparation a high 
tL'injKTalurc has been employed. a» is the case with Ruasian and 
Swedish turiKMitine. 

Limonenc if< strongly dextro-rotatory, and its tetrabromidc is 
also optically activo. On the olhpr hand, dipi?nleno and its tetra- 
bromide are optically inactive, ami the nddition-producls w^hich 
Umonenc and dipentenc >*ield with the hydm^n halidi-s are 
identical and inactive. The latter yieki dipentcne by the iq-ilitlinK 
off of hydrogen halide, fto thai hinonene can in this way be converte^l 
into dipetitene. 

Wallach diHcovcred in pine oil a liydnwarlyTU. Ci„n,fl, which 
nilales llit- plant- nt pilarizulion l» Hm? U'fl to tlii' san»e (^\le-nt u 
limoncne to the right, niid which fnmi its genrral character is to be 
l<M)kfd H[>im HM thf ojiliral antitlu-^ia of lirtioncnc. When tliis 
laro-Hmomnr. ia mi.\nl with thr ih-xlrn-innditirntion, dipcnti-nr. is 
form<%l, from which it followH that dipcnleno is to be regarded as 
the racemic modification of t he limoricncs. 

Pinene can bt- fonvertwl into <iipentene as follows. By the actteo 
of water containing nitric acid, it taki's tip three molecules of water, 
fonning lerpiji Ayt/m/f. C,„Hs/)^ f H.O. On JM-ating, this lows a 
iiioIwuIl' of water, yielding Urpin, CH^Oj. which by the usual 



45* 



OUGANIC CHEMtSTRY. 



linkings in its molecule. It in converted by oxidation into an alde- 
hyde, C,aH,«0, gcranial, nhHwing that it must be a primary alcohol. 
Geranial is sometimes also called citral, owing to its presence in 
oil of citron. On heating nith putaistum pyroeutphate, eilral 
nt-stly IoR«* watiT, being converted into rvmene, C,^,,. Cieraninl 
also loses water when treated with potassium pyrosulphate, yielding 
a tetpene, C,»H„. !;<7yiwiVnr, Ix)iling between 172* and 176"- From 
its additive power, this rompound seems to contain three double 
linkings in the moleaile. 

Closely relatetl to geraatol are linaUd (from oil of linalcts), and 
rhodincl (from oil of rosee). They have also the formula C„»H,,0, 
and are converle^l into nlral by nxklation. This is pmhably 
aceompanie«i by an alteration in tbe positions of the double lick- 
ings present in tbe compound. 

The ConxtitDtion of the Terpenes and Camphors. 

362. A coiiipound C,^„ lias six hydrogen atoms Ices t haii a sat- 
urated fatty liyUnjcarlion of ten carbon atoms. C,.Hb. An aro- 
matic hydrocarbon with saturated side-chains and ten earlmn atoms 
has the formula C,oH„. The terpones, thrreforp, f^<'iii)y a poetttoit 
intermediate between the nroniatir and the saluralcd fatty scries. 
Their propcriies correspond with this view: on the one hand. Ihey 
are leadily converted into aromatic compounds, especially eymene; 
on the other, they exhibit many of the properties of aliphatic com- 
pounds. The difference of six hydrogen atom? between them and 
the ^aturatcd hydrocarbon'! with ten carbon atoms nii^ht liccnu^rd 
by the presence of three double linkings, which, indeed, sceni lo 
be preseni in gemniene. .Since, however, the other terpenes do not 
add six monovalent ntom<t, but some only four, and others only 
two such atoms, they mu-st contain one or more clo-^ed chains 
of C-atom<{. in addition to double linkings. As in each rk»ed 
chain there are two atom? of hydrogen 1cm in the molecule 
than in the corresponding open cliain (liexane, CaH,, ; hexa- 
mcthylcne, CaHu). it fdlon-s that in the terpeocs which add 
4Br and 2HCI, there nwi^l Ix* one closed cliain and two double 
linkings; and in the terpenes which add 2Br and IFICl, one 
double II nking and tw-o closed chains. The problem is to determine 
which are the ring-systems in the different terpenes. and what ate 
the [Hisiiiuiis of the double linkings In the molecules. These two 




CONSTtTUTtON OF THE TERPENES AND CAMPHORS. 457 

questkitui liave not yet been fta(i}tfacto*-iIy answ«re(l for all tcrponc-s. 
For nearly all, twu or mure coiislitutioiial forniulir have been pro- 
potiptl, aitiuiig which no (leriiiit(> Sfli-otion has Ix^on inacte up t(v 
the prrsrnl. Owing to the reailinfss with which many terpencs 
yicUl cynicnc, it is supposed that the carbon-nucleus of this com- 
pnutiil, a closed hexagon, ia present in them, with methyl and 

isopnipyl in the pam-posjtion: CH, — 'C / — CH(CH,),. Tlip 

positions of the double liiikings in this nucleus have been deter- 
mined for ter|)enes which yield tctru-additiun-products; for sodic 
of thetn with considerable certainty. Fnr example, tbo adjoining 
formula u* almost imivrrsnlly asaJRned to limoncno, 
one of the double liitkiiifis l)einK in the sido-cliain. 
Tliis fornnila explains the different behaviour of 
the two double linkinjzs, owing to their V>eing situ- 
ated within and without the ring respectively; 
linionenc adds on only one molecule of HCI by 
treatment with dry hydrochloric- acid gas; tlie 
serond double linkinf; is only bnikeii by treatment 
with mnist. hydrnphlorie-acid pas. [t furl her ex- 
plains the npliral activity, since ihe ratbnn atom 
which is marke<l with an asterisk (*) is asymmetric. 

Terpinnlene also gives letra-addilinn-pmdiicts, and has. there- 
fore, two double linkings. One of these is situated in tliccymcnc- 
nucleus, betwcentwolertiaiy C-atoipa: 

CH CH, 

'\_/ 

CH, CH, 

Terpinclrne 

This la proved by the fact that Ihiji body yields a ciystulline. blue 
addition-pimUict wUh nitrosyl chloride. This ia a chaiactciisUo 
of compouitds which have a <loublc linking between Icrtiaiy carbon 
atoms >C=C<, as has been indicated in the case of seveial such 
substances. 

Compounds with the formula C,„H„. which can only take up 
one molecule of IICl or twn halogen atoms, must have two closed 
rings. A hexagon of carbon atoms is also supposed to exist in 
Ibcse. In the ca&c of pinene the second ring is probably fo.ir-sidctl: 



CH, 

C 
HC/\CH, 

H.cl^/'CH, 

r 

GH, CH, 

LltD«l)C(IF ■nil 
dlpcttlTM 



A. 



45» 



ORCASIC CHBMiSTRY. 



HC 




Baeter assigns to thU compound 

the adjoining formula, in wliich the 
ifiopropyl-grtmp of cyniciie ia linked 
by its tertiary carbon atom with tlie 
mcfi-carlion atom of llic tictOKun. 
This formuin at tril)iilrK two six- 
sided rings and one four-sided ring 
to pinene. In «amphene the ter- 
tian,* carbon atom of lh«' iwii»ni|>yl- 
groiip 13 linknl t<i thir lii'iuwuvriiig "^ 
at the }Mra-pc«ilion, so tlmt it con- 
tains one six-si(i<'(l ring ami two 
five-sidcil rinRK. Analopoiis constj- 
tuti(H]al formula arc assigned to 
the other tcrpen<^, C,(,n,fl. 

383. It hiiti bf-cn nii-ntjonod that 
the fiMmphonf liave iho forniiila Cj^H^O, 
C,ofr,/>. C,„n,,0. MPiithoI is an ex- 
ample tif a cotnpniitid with thr first: of 
these fonriul8\ It is an alcnliol, sm], 
accDiilitie; to itM formula, (;oiitain5 two 
hydrogen atoms Itss than « sattiraiwl 
aleohol, C,^HjjO, Since menthol does 
uul funii addition- pnHltict^, it muat 
liave (lie one cloMHl-ring structure. 
Tlie readiness of its conversion into 
c>inenc icidicates that it eontaiiBK a 
oymeiu>-nucleus, its t-oii^litutiou Uring expressed by the adjoiaing 
formula. 

A eompound with tho formula C,„]I„0 can only 
liave an open chain, if it ha.s double or treble 
iiuking)! in il^ molcculr. This is tiie case with 
geraniol, C,„II,,0, which Iul-* twn double Itnkirigs. 
Konieol, whirh is iaoinrric; with it, does not jiosscsfl 
any addilive power, and Jtd deficiency in hydrogen 
compared to a saturated compound must be 
cBiwCKi by the preaeiii-e of two closed rings, the 
same liciug then true of ordinary tamphor, C,»H|^. 
Tlie oxidation of camphor affords a closer imnght into its consti- 




CH, 

"A 
f 

C.H, 

HmnkAl 



OH 



CONSTITUTION OF THE TERPENES AND CAMPHORS. 459 



tution. Bredt has shown that the first product obtained by its 
oxidation is camphoric add, which on further oxidation yields 
camphanic acid, the latter yielding camphownic acid on still further 
oxidation. It may, therefore, be assumed that the two first-named 
acids, as well as camphor itself, have the same carbon-nucleus as 
cainphoronic add. 

The constitution of the tribasic camphoronic acid follows from 
the result of its decomposition when submitted to dry distillation, 
a treatment which splits it up into trimethylsuccinic acid, isobutyric 
acid, and carbon dioxide. This is accounted for by the formula 

^g»>C-COOH 
CH,— C— COOH , 



CH— COOH 

the formation of the first acid being represented by the decompo- 
sition A, and the second by B. 

From a consideration of these and other known properties of 
these substances, Bredt assigns to them the following constitutional 
formulae : 



CH,- 



-CH CH, 



CH, 



-CH- 



-COOH 



CH, 



CH,-C-CH, 

-t 



-CO 



CH 
CH, 



.-i-CH. 

C COOH 



CH, 

Camphor 



CH,- 



\ 
\ ■ 
No. 

CH,— C— CH, 



-COOH 



CH,- 



-C- 



-CO 



CH, 

Campboric acid 

COOH COOH 

! 

CH,— C-CH, 

CH, C GOOH 

CH, 

CamphoroDic acid 



CH, 

Camphanic acid 



The formation of cymene from camphor is indicated in the fo> 
muia of the latter by a dotted line, showing the breaking of the car- 



46o ORGANIC CHEMISTRY. 

bon bond in such a mamier that the isopropyl-group takes up the 
pora-positioD to the methyl-group. 

Recent work affords confirmation of the correctness of Bhedt's 
formulifi, that of the one for camphor being proved as follows. 
According to it, there are two asymmetric C-atoms in the molecule, 
indicated in the formula by bolder type. When, however, tho 
CO-group is transformed into CHj, the asymmetry of both atoms 
vanishes, and the molecule must become optically inactive, pro- 
vided Bredt's formula is correct. This does, in fact, take place. 





364. The simplHt possible compound of tbis nature is oiie 
cnntAioing lw« Ix^nzene-nuclei directly linked to one another, la 
addition to this tlifjre are nompoundu in uhit-li 1l»r Ix-nzenp^niwlei 
are indirectly CDniiecl*d l»y a carbon atom, or by a rliain of 
carbon atoms. A few of tliesc substances will be deacnbcd in this 
section. 

Dipheiiyl.C,H,C,H.. 

Diphenyt can be prepared by Frmt;'s sj-nthcfiis (268) from 
bromobfnzenc and sodium. Another method for ttio prcpsration 
of the derivatives of dtphenyl, the conversion of hydrazcjbeiiu4ie 
into benzidine, was menlinned in 891, On removing the atnido* 
groups from benrJdine by niesnfl of the diazo-reartiun, diphenyl is 
formed. This methf>d of formation also afTonls a proof of the 
con3tilution of benzidine. 

The iirejiaralinn <if diphenyl is usually efTeeted by passing ben- 
zene-vapour throiiph a red-hot tube. It is converted by oxida- 
tion inio beozorc aeid; this, together with iis synthesis by FirrKi'a 
methtHl. is a proof of itseon.-ititulii>n. 

Diphenyl forms larjje, tabular, colourless cryslalTi, n^adily soluble 
in alcohol and ether. It melts at 71°, ami boil.t at '2b-\°. 

The isomeric suhslit-iltinn-prnducts of dipheuyl are much more 
numerous than thn^e of Ijenzene; a nionosiibstitiilion-pn"iduet eaii 
exist in three isomeric forms, the sulMiliturnt being in the orffio: 
meta-. and jwm- positions to {he bond lirtween the benzene-nuclei; 
in a diaobptitntion-pHKhict, l>oth substituenta may be linked to 
the same benzene-nueleus, or to different Iwnzcne-nuclei, etc. 

Benzidine is of teelinical iniporlancc, because many of the 
azo-dyes are derived from it. 

461 




463 



ORGANIC CHF.MISTRY. 



Di phenyl methftoe. C,H,CH,C,Hs. 

368. DiphenyUnelhane can be obtained from benayl chloride, 
C,HbCI1,CI, or from methylene chlonijc, CHjCl,, by the action of 
bcn?«ne aiid ahiniinium ohloridp, \\s lii)iiinlofrii(>8 ftre obtained by 
the octiun (jf btnizom* and t'niipent rated siilphtirie acid upoa aldo- 
liydejs; thus, aft'taldclivde yields ax-diphaiylflhaJte : 

^" " " CH 

niC.TL = <^"_.r^Mii 



CH,-C 



'' ^ h!c;h: 



en, c<^.«jj^ + H,o. 



When derivatives of benzene are substituted for benzene itself, 
many derivatives of di phony lmetha.iiL' ran Ijo obtained by the 
a{>plipaiioii of the syntlitws just mentioned. 

OipheiiyliiiL'tliaiif is crystalline; ii melts at 2fi* boils at 262*, 
and has an ndnur resembling that of orange-peel. Oxidation with 
chromic acid converts it into bemophenone (300). 

A derivalivo of diphenylniQiliitno, in whicti tbd be D£i>a»- nuclei are 



■till directly Unlced, is^Etomiff, 



c,n/ 



II is foriDod by leading 



the vnpour of diplicnylmailiant! throuKli a red-hot tiilw. It cry»tallitcs 
from alcohol in lliicrescenl leaflets, from which ittlerivfaitsnnme. Ii 
Uielta at 113*, and buils a.% 293°. U jriuldared uvudles vtith picric acid. 
Tlie cniigtil(Hii>n of niioreii« \s. thiix nxiAbliihod. U Is couvcrted 
by tho action of oxidiziug-agciits into tiiphent/knrkttvne, wbtcb ha*J 



tlio formula 






CO, Ibis being proved, by its TortiiatiDn when the 



V 



C<U,-CO|0. 
Ciielnm soit ot diphenie acid, { | /C;i. is distilled. Diphentc 

c\H,- icotr 

acid, for itn ]uii-l, » obuiiiod from »• bydninobcnxolc acid by tbe b«aa-j 
tdiiie-tranKroiiiiHlion cS9li. ami ftiibM/i^iicnl rliminalion of ibe amide 
grouptt ; 

! Ill 

coon UOOC HOOO COOH 

It follows tiiat the carhoiijl-gmup in diiihenyleiieketoac is linlccd at 

tho orMo-positioii la bolh thft bfttiicne-nucloi; it hn«. ihcrefore, tha 

structure 

.and Iluoreno itmelf 





H, 



TRIPHENYLMETHANE AND ITS DERiyATiyES. 4^3 

This receives con&rmfttion from the fact that pbthalic acid ia the only 
product obtained by its oxidation. 



Triphenylmethane and its DerivativeB. 

366. Triphenylmelhane, CHCCjHs.),, is formed from benzal chlor- 
ide, CflHj ■ CHClj, by the action of benzene and aluminium chloride ; 
from benzaldehyde and benzene in presence of a dehydrating- agent, 
such as zinc chloride; and from the interaction of chloroform and 
benzene in prraence of aluminium chloride. It crystallizes in beau- 
tiful, colourless prisms melting at 93°; its boiling-point is 359°. 

A series of important dyes, the rosanilines, is derived from this 
hydrocarbon. Triphcnylmethane itself is not employed as a basis 
for their preparation, simpler substances which are converted into 
its derivatives being used instead. The formation of the dye takes 
place in three stages; that of malachile-green furnishes an example. 

\Vhen benzaldehyde and dimethyianiline arc heated with zinc 
chloride, tetrametkyldiaminotripkenylmethane is formed; 



H ^ 



C,H.-C:|0+jj 



H 



<3>N(CH,),_„(. ,p„ p C,H.N(CH,), 



The carbon atom of the aldehyde group, therefore, furnishes the 
" methane carbon atom " of tri phenyl met hane. 

This substance is also called leucomalnchile-green. It is con- 
verted by oxidation with PbO, in hvdrochlorie-acid solution, into 

*. r K- 1 C,h1c[C,H,\{CH,)Jj .... , 

the correspondmg carbinol, ah ' "'"'^h is a colour- 

less, crystalline substance, like the leuco-compound from which it 
is derived. Being an amino-base, it is capable of yielding salts; 
thus, it dissolves in acids with the formation of colourless salts. 
When such a solution is warmed, water is split off, and the deep- 
green dye produced. The latter, either as a double salt with zinc 
chloride, or as an oxalate, is known as malaMte-green. This split- 
ting-oft of water may be represented in several ways; it is usually 
supposed to take place thus: 



.464 



ORGANIC CHEMISTRY. 



C,H,N(CH,),riCl 



i^Hl'^^^^ 



N(CH,),.T1!CI 



-H,0 



C,H,. 



N(CH,),' 




h 



According to this mode of reprcfli-ntation, the process is analogmis 
to the fnrmolion of quinone frnm quinol. in which the colourless 
quinol is convi^rted into thedeep-ycllow quinone. 

The three slages neeessnry to the formation of the dye fnay» 
therefore, be definf^d iw f()II(iw"fl- 

1. Forniatioii of a Icuca-husc (coJourless), a derivative of 

2. Formation of a eolour-tiafe (eoloiirloss), a derivative of 

H0.C{C,H,N1U),; 

3. Formation of ihi^di/e, a derivative of 



p(C,H,NH,-Ha), 



Rcdiiclion converts the dyes bat-It u^aiii into thfir Icuco-basea, 
two hydrogen utoms being tal<cn upduriii)r the reaction. 

Cn/N(«/-i\W('((hcxanietlij'Uriaminotr(phci)ylniiClhiinc) fumitilirs an 
cxeellcrit e\amjtle of a phenomenon also exliibili-d by other ans- 
lof!OUE basic substances. When on equivalent quantity of a base is 
added to a salt of crystal -violet, Uio liquid still remnin>i coloured, 
haa u 8troii): alkaline reaction, and eoaducle an clcctrie current; Lite 
eohition sliiwly hecomes colourless or standing, wIiph il is no longer 
ulkaliiii.-, iind ile [Hiwer of conduiMinK an elcclrio current ha* ceased. 
Tlie liquid now contains a colnitr-hrt-sc Thej*p [ilinnorneoa are 
an&logouit to the conversion of nvids into p^eudo-scidii (SBl). For 
this reason the col(iur-bii.se mny be looked ujion as a pftudo^taxe. 
Accordinc to tliis view, on addition of the equivalent quantity of 
JIaOII to L-rysliil-vioh-t, the Inie hase. 



CCH.),Nt:.H.>C 
tCH,J,N C.H. ^ 



— ^Ull 



is at first present in thcwJutJon; this true base, however, after ataixl- 
ing for several hours at 25°, climiges into the colour-base (pseudo^ 

base)* 

(CH.>,N C.H.>p,C\H..\(CH,V 



TRIPHBNYLMETHANE DYES. 4^5 

Hantzbch has been able to assign the character of a pseudo-base 
to certain substances other than those mentioned on p. 464. 

PararosanUine is obtained by the oxidation of a mixture of 
p-toluidine (1 molecule) and aniline (2 molecules) by means 
of arsenic acid or nitrobenzene. The methyt-group of toluidine 
is thus converted into the " methane carbon atom ". of triphenyl- 
metbane : , 

X.HrNH, C,H,NH, 

CH,/ C,H,NH, + 30 = HO~C. C,H,NHj + 2H,0. 
C.H.NH, \C,H,NH, 

This colour-base yields a red dye with acids, from which it can 
be precipitated by alkalis. It is converted by reduction with zinc- 
dust and hydnwhloric acid into paraleucaniline, HC(C9H,NHj)j, a 
colourless, crystalline subslancc which melts at 148° and is recon- 
verted into the colour-base by oxidation. The constitution of 
paraleucaniline is shown by its yielding triphenylmethane when its 
amido-groups are removed by the diazo-reaction. On the other 
hand, paraleucaniline can be obtained by the nitration of triphenyl- 
methane, and subsequent reduction of the trinitro-derivative thus 
formed. Paraleucaniline is converted by oxidation into triamino- 
triphenylcarbinol, which, like malachite-green, splits off water un- 
der the influence of acids, forming the dye : 

C^C.H.NH, -H,0 - C^„H^NHi 
i \C,H,NH;HC1 V',H,:NH,C1. 

OH 

Another important dye related to triphenylmethane is rosaniline. 
Its preparation is similarly effected by oxidizing a mixture of aniline, 
o-toluidine, and p-toUiidinc in equimolecular proportions with 
arsenic acid, mercuric nitrate, or nitrobenzene. In this reaction the 
methane" carbon atom is obtained from p-toluidine as follows: 

NH, ■ C.H. ■ CH, + C,H/CH,)NH, /*^'""' < N H, 

p-Toiuidiae ;:;^''^'S"*' +30 = JI0C^C,H,NH, +2H,0. 

-I- 0,Hs-I\Hj \CgH,N"H, 

The hydrochloride of the rosaniline ba'^c containing one etjuiva- 
lent of hydrochloric a(rid is called niat/enla. This siil)stance forms 



466 



ORGANIC CHEMISTRY. 



beautiful green cn*Eta]« with a metallic lustre, which dissolve in 
water, yielding a goUilion of an intense <leep-rpil cdimr. 

The colour of the majtenta-sohilicin is due to the monovBlrnt 
cation, (C„H„N,). becauw such sohitions are almost completely 
innised, a.*< is shown hy the slight incrra'f of Ihrir iimlreiilar rtin- 
(luclivity on (tirtlier dilutioti, Momivrr. the fioluliims of all the 
tiiajijeiita salts— ehloride. bromide, sulphate, etc.— exhibit the same 
obsorption-spectnini Ot solinions of ciiiliiriolpcular enneenlration, 
which Ih an iiHliration of the picwnee of a coiistiluent common l« 
all of thum (the ealion). 

Tbe BRita contaiuinji; three cqaivnlcntA or nclfl an j-ellow, tlie red. 
monovnleut. ention Imrinj^ beoii cunvcrlcd into (lie jrllow. triviilRUt 
one ; MR II n-Kiilt. nt i lii«. iiingnnln dissulvml in otiwss of hydnx-hlunc 
ovUI, (fields a nc-nrl> colourlnB aolulioii. Theee salta arc, bowovor, 
v(.<ry i-cHiJity liytlrolyxeii, as sbown by tUe reappeamnoe of ttw pnI 
colour when lliin suhiUou in bjrdrochlorio acid is [louird inlo irater. 

Many derivatives of pararosaiiilbie and rosaniliuc are known, in 
which the hyiiropcii atom* of the aiiiido-gToii[ts liove been replaced 
by alkyl-radielee'. They are all dyes. The violet colour lMtroiiie& 
dix>]j4>r an the nimihcr of methyUf^roiips present inerea^e^ {323). 
PenlAmethylpararoisaniline isHold under the name" methyl-vinlet." 
'niien one hydrngi'U uloin in 4>a(^h nf the amido-^Hipit of rosanUinc 
18 replace<l i>y phj'iiyl, a blue dyr is formed, called " aniline^ihie." 

Tli« »lkyl-giv>U[« nere fomierlf inimdaced into pnramaaDitiBe 
ta th« ordiuArjr way, by means of an alkj-l «)doh(li> or ereti iodUl* 
Tlicw innthai:!* liave hing siiictt gifeo pUc« io others, Iwiter soilnl 
to tbe pr*>i>anitiDii of (bv ulkyl-dorivatirct. Fur vxitmple. methyl* 
vtoltt is obt»iiii;il \ij iliu oxidxlioii of •tlmeiliylaiiiliiiu with potiu- 
sium cblonito ami ciipric; chloride ; tbo mcttiario carboti atom is to 
tbis case obluinMl from on« or llin mei hyl-^roups. 

Aniliue-bloi', or tripbetiytrowiiiiline bydr<x-lilorid«, isobtafaed by 
hentiiix rosniiltinc wiih aiialiiieaiid j> weak nci<l.8ucli as beanie acid, 
vrh»r<j by r.hc amido-groupa iu the ro«nnitino an> repliio«<] by aailldo- 
groups, (be ammoiiiA wl free entering iuto pumbiDntioii nilb the 
acid, Tbis procew is «XACIIy analugoait to the fonoatiou of dipheoyl* 
aralDft from aniline hydrochloride aud aiitttiie (2fi4). 

367. Dyes formed from hydroxy! -derivatives of triphpnyl- 
mcthanc arc also knon-n, but are much le$.s valuable tbaji lho«e 
jiiat dcecril>ed, on account of their being difhcult to fix. Roaotie 



m^ 



TRIPHENYLMETHYL AND DIBENZYL 4^7 

CaH,<QTj' 
acid, q/t- ti qtt obtwned from rosaniline by means of the 

diazo-reaction, is an example of such dyes. 

Malachite-green and the pararosaniline and rosaniline dyes colour 
wool and silk directly, and calico after it has been mordanted. 

It was stated in 321 that the fixing of dyea upon vegetable or 
animal fibres must be looked upon as a chemical combination of the 
compounds contained in the fibre with the dye, analogous to the 
formation of snits. The following is a proof of this. The co1our-ba,ie 
of rosaniline is colourless; when, however, wool or silk is immersed 
in its colourless solution, it becomes gradually coloured, as though 
an acid had been added. This can only be explained by supposing 
that a conii)ound in the fibre unites with the colourless base, forming 
with it a salt of the same colour as a solution of the dye in water. 

The phthaleiiis, dyes related to triphcnylnicthane, have been 
mentioned already (327). 

GoMBERG lias shown that zinc reacts with triphenylchloro- 
mc(hane, yielding a compound with the formula CC9H5)3C. This 
he proved by analysis, and by the cryoscopic determination of 
its molecular weight. This compound can be precipitated in 
crystalline form from a benzene-solution by the addition of acetone 
or ethyl formate. 

This substance, triphenylmelhyl, is very remarkable, for it is 
the first known instance of a compound containing a trivalent 
carbon atom. It possesses notable additive- power; thus, it com- 
liines at once with the oxygen of the air, with formation of a i>er- 
oxidc, CCbHj)iCO — O-CCCgHJ,; it instantly decolourizes iodine 
solution, yielding triphenylmelhyl iodide. With ether it yields a 
crystalline substance of the composition 2(C,Hs),C + (CiHj)^©. 



^ 



Bibenzyl and its Derivatives. 

368. Dibenzyl, CoH^ • CH^ ■ CH, ■ C^H;, can be obtained by the 
action of sodium upon benzyl chloride: 



C,H,-CH,| CHNa, + CI |CH,-C,H,=C,H,CH,.CH,C,H,-K2Naa 

This method of formation shows it to be symmetrical diphenyl- 
clhane. It melts at o2^. 



468 



trgj^nic chemistry. 



^ 



■.i 



Symmttriail diphcrttjUthykm . C,H.CH:CH-C,H„ M.P. 12.7*, 
ie usually callod ntiibcnc. It cnn be obtained in various wnyjf, a 
tX]>icAl mpthod being the distillation of the phenyl eater of fumaric 
ftcid, wKich eliminates two molecule!) of CO,: 

C,H,|^l-CII:CH-|COjC,[i, = L»CO, + C.H,CH:CHC,II^ 

Stllbi>ii« forma an &cUlitit>n<^»rwlittct with bromtttc, from which 
tatan, CJitC=CC,Hf '» oblained by splitting off 2HDr. Tolan 
can he reconverffd into stilbeme by curprul rudurtion. 

p-0i«Mii'niM/i7Afnf, NHj-CiHifH:!'!! (■,H,-MI„ran he nlitaioLil 
by Irpiitment of /i-nit rrtbpnxyl chloride, (TH, ("■(!, H,-Nf)., with alco- 
holic; [lotit.-'h, and siilwcrnicnt rt-duction of (lie \)-(hniirauiiUn:nc thus' 
fonnc-d. It i» ihi^l as a butJH for t3)e (nvpuratioci of ccrlnin dyt^ 

Derivativi*« of dilx*tuyl are (ihtaiii(><l by tt>e coiulons&tk>n oE 
henaalileliyde i n presence of potassium cyanide ; tor ex&mple, 
baizo'iit U thus fortnfd: 

C,H»-C^;^gcc^j = C,H,CO CHOH-CjH,. 

B«nKO>D 

It has the character of a ketone alcohol, siiief U lakes up two hydro- 
gen Rtonis, iiiili fiinmififin nf a dihydric kIcoIioI, hytirobtmain, 
CaHj-CUOH-CllOH <',Hi; on oxJdalicjn ii yk-klsu tlikrtone, UtuiI, 
C.Hs-COCOC.Hi. Hcnitoiii fontuiiis tin; K"»up — CHOH-CO — , 
which is prcrril iti the suiiurs (806). U also l>o^,sps*^eft proper- 
tics vharactcristic of the sitgars; Ihu^i, it redures iin ulkaliue copixr 
solution, and yields nit (j^aione. 

Itenzll is a yellow, crys.tftl]inf f-iiUslanfe. As a <likotonc it' 
unites wiiK two molecules of hydravylainiiii- lo form a »li«»xin»p. 

*M. Bcntildinzimt cvists in Ilirpo i-iomcrie forinH, Ihe number 
Oicoreilcally jjuvi'blc from h con-idcration of the »terc>oi»omcri$ta of 
nitrog«'n derivntive.'* (801): ^ 

C,H. C^C (-.H, C.H, G-C C,H, C.H.C C.C,H " 



l! 






NOH HOK 



J OH Hoi. 

fitrtibeusiiaioxl me 



\0H NOH 

JnipflllMIlliyiDXllDO 

One of lh«e ositnes vciy rMdily yifhh iin unhydritie, and is Ihcr^. 
fore assumed to have tho two hv droxyl-groups in close pruximitv 
the ityn-fnriniiU. One of (he oilier ilioxitncs is the moHt Kiahl ■ t 
the three compound*, nnd mn be obtained by varioua tnt>an><- th 
third dioxime ran be reudiJy Iran^formeU into this Ktahlc modific ° 



BENZIUC ACID. 4^9 

tion. It is im>bable that the stable dioxime has the symmetrical 
or a?ifi-formula, so that the ampki-torm.v[& must be that of the un- 
stable modification. 

When heated with alcoholic potash, benzil takes up one mole- 
cule of water, undei;going an intramolecular transforTnation^ with 
production of hemUic acid, a reaction analogous to the formation 
of pinacolln from plnacone (166): 

G^ COCO-CA + H,0 = cS^^^COOH- 

bensllic Mid 




CONDENSBD BENZENE-RINOS. 

3T0. Condensed-ring catnpoiinds contain two or more closed 
cluuns, with C-atoinB common to both. Such compounds arc pres- 
ent in tlie higher-boiling fractions of coal-tar (267), Next to the 
phcaols, napiiihfiicne is the principal panstituont of the Kcond 
fraction, carbolic oil, and of tlit? ihiril fraplinri, crecsote oil. The 
aiithraoeno oil contains anlhractnc anil phcnajiihn-nc, in additioa 
to otJier hyilroparbons. 'I'hvse three compounds and some of their 
derivative;) will be do«cri(x-d here. 



I. HAFBTEALEKT. C,„Ht. 

This hydrorarhoti is present in cimsiderable qiiantilj" in cotd-tar, 
from which it is readily obtained pure. The cnide cryHtaU of 
naphtlialenc prccipitAtc on ctjoUiif; fniin the fraction panning over 
between 170° and 230°, and are se|>arat<'d from liquid impuritie 
by pressure, which are further <.'!iiiiiimted by conversion into noa-i 
volatile sulphonic aeids on warniing the crude product with small 
quantities of concentrated tulpliuric acid, and di&tilling with steam 
or subliming, when pure naplitlialeiie comes ovtr. 

It crystallises in shining plaies. melting at 80". and boiling at 
218". It is insoluble in water, but readily soluble in hot nieoholj 
ftnd ether; it dissoh-es to a very email extent in aOd aJcnhol. It 
has a chorfteteristie odour, and is very volatile; it is always prraent 
in coal-gas, whate illuninating power U to a large extent due to 
its presence. It is extensively employed in the manufacture of 
dyes. 

The formation of naphthalene on passing the x-apcmm of manyJ 
compounds through a red-hot. tribe, a proceea somewhat simihu' tol 

ithat which takes place in the retorts of the gas-work» (S67>, ex- 

IplatDs its occurrence In coal-tar. 

470 



NAPHTHALEUB. 47' 

The constitutdoQ of u&phthaJeDe was pnn'ed io 3fi3 io be 

H H 

H H 

Thin view iii eonfirm<vd by tite two fallowing syntheses. 

1. o-XyljIiiiw bromide w canvprteii by treatment with 9odio> 
ethanetctmcarboxylic ester tiit« hydronaptUhakruMraearitaryHe 
eater: 

,ai,]ST NaC(COOC^,), .CH,— C(COOC,HJ, 

^CH,Dr NaCtOOOCjH^, ^CH,— C(COOC,H,), 

o-Xrlyhn* brooatil* ' 

On .inpunifif.^ition, t)ii.« rompniind ^plit.i ciif two molecules of carbon 
dioxide, forming ht/dreutaphUioiett^UarliHiTtfiic arid: 

XH,— CUCOOH 

C^< 1 

^CH.-t'H CXX)H 

nbotw silver salt rcitdil)' loecs t«-o mvltMruIrs of carbon dioxide und 
two atointi of hyclroicfn. yiddin^ iiai>)iihiilcnc. 

2. On bcBtinc jilii-nyli»fjcrotonic wid ii coiivcrt«d into a-noph- 
thol, a liydraxyl-dcrivativf of napIilliiilcDe: 



H CH 

HO 

Ptieiiyliux-riiUinli: aclil 



~H,0 - 



CO 

OH 



Nopbthalene behaves in all respects as an aromatic hydrocarbon: 
with nitric ncid it yields a iiitro-derivative, with sulphuric acid a 
eulphonic acid ; its hydroxyl-derivatives have the phenolic character ; 
the amino-corapoiinds undergo the diaro-reaction; etc. The great 
reeeniblancc in prcipprlJL's between benzene and naphthaJene indi- 
cates simUaxity of structure, aud to the latter is ajsdgued the 
formula 




i 



47 » 



ORGAWC CHBMtSTRY. 



Partial hydration converts the centric bonds in naphthalene, 
like those in benzene, into double bonds, since naphthalene dihydride, 
C,oH,o. readily fotTiis an addition-product with bniminc, like other 
aubstancra containing a doubie bond. 

3T1. Naphthalene yields a much greater number of substitution- 
pnxiuetK tlian Ijenzene, the riiimber obtained eorrosponding to 
those tlieoretieally possible fop a compound with the above for- 
mula; tliiB fact supports the constitution indicated. 

A cooipouud of the formula 





must yield Ivso isomorie monosubstitution-products. Substitutioi, 
can take place at a carbon atom directly linked to one of the two 
C-atoms common lo both HngRO. ■(. 5, or 8), or at one of the othera 
(2, 3, 6, or 7). which are also similar to one another. Two series 
of monoBubetitution-produtts are in fact known; those in which 
the hydrogen at I, 4, .5, orK has lieon replaeed are calWl "-deriva- 
tives; when liydrngi'n is subntiUited at 2, 3, S, or 7, the products 
are termed ^-derivatives, 

A gn-at tmnilHT of [|isllbstitutioll-|t^>dll<■l^ Is possible; for two 
similar subsIitiiL-nts it is 10, and for two di»»iiiiilar substituents 14: 
many of these have beca obtouied. The ten isonwrrs a«; denoted 
by the numbers 

1:2. 1:3. 1:4. 1 ;5, l:fi, 1:7. 1:8, 2:3, 2:6, 2:7. 

In any other arrangement the grouping is identipal \^■^th one ol 
these; thus, 2:.') = 1:B. and li:0 = 2:7, p\€. Knr three siiniW 
fiubstitiients the mimber nf powiible isomers is niiich Rrt^ater and 
still Kreat-er fm- three <lisdimilar ones. The difiubNtitution-proclucls 
witli the Hubslilueiits in rlie wanie ring are eallod ortho rtivla and 
jwiw; when they are in different riiijrs, the oompovmda are usuallv 
disliiiKiiished by numlxTs, or aomctinies l»y letters • thiia "~ 
compound 4:5 1'* also intlicatcd by *n*' , and one 3 : 6 bv BS' Tl 
positions 1:8 and 4:5 are also called the PTi-pnsJtions • in «■ 




I 

I 



twn respects thcso rpscmble the orMa-poationa. For ex&m. 
pcn-nap/UhcUcn^icarboxylic add, 

/^^V-CXK)H 
/^~S~COOH 

reserablw o-phthalie acid in being able to form an anhydride. 

372. On account of the great number of isoiiit-rs, the orientation 
of naphthalene derivatives is soinetinies very difficult, and 
positions occupied by the substituents in many of those which are 
known are still uncertain. Tlie same method of orientation is 
employed as for the bcnisenc derivatives, the conversion of com- 
pounds whose side-cliaitLs occupy unknown positions into utheia 
with Hulistitiientfi whosi! piwititms have l«vn det^rmineii, 

OxidaUoii is another important aid in their urientalton, and ia 
employed t« Jetermiiie whether the suhstituents are attaehed to 
the aoinc or to different rings, as iv<'ll as their pa-ation relative to 
one another. Thus, suppose the position of the uitrfH-Rroupfl in a 
dinitro naphthalene has to be determined. If it yield* phihalic 
acid on oxidation, the two nitro-gToujiFt mii.it be in union with the 
same ring, that one which ha-s been removed by oxidation. If a 
dinitrophthaUc afid is formed, thiK ai»o |imve.H that the two nitro 
gnjups an- linked to the same ring, and ihe orientation of these 
gnnipM in this arid should indicate their relative poation in the 
naphthalene derivative. Lastly, if oxidation yields a mononitro- 
phthalic acid, one nitro-grtinp is atlnched to raeh rinp, and oripnta- 
tioti of the mononilrophlhalic acid obtained will determine tha 
position of one of the nitrogroups. 

SnbBtitation-prodnoti. 

373. The homologues of naphthalene — methyl-derivatives. 
ethyl-<ierivativp8, etc. — are unimportant; thry can be prepared 
by FlTTlc'ti method, or that of I' itifDtL and Crafts (288. 1 and 2). 

a.M ethyl naf^hlhiiUiir is ii liquid, mid Ix^iln at'J-J(P'24'J°; i9-inrthyl- S 
naphthalene is « solid, und inettj'iit 3"."": both arc prwi-nl in cotil-lar. ^^ 
On oxidation, they yield "-na-phthoU and fl-naphlhok acid respect- 
ively, which rpMemble btTiioIc sriti in tlieir properties, and are con- 
verted into naphthalene by di^tillstiun with lime. 

a-Chtoronaphthalcne anil a-bromonaphihalene are respectively 
formed by the action of chlorine and bromine upon bcnltng naph- 



I 

I 

1 




474 



ORGANIC CHEMISTRY. 



thalene. Although their halogen alom is not so firmly linked 
that in monochlnrolimzcnR or inonobromobenitene (86ft), ihey 
arc not decnmiinf'Cil on hniling with alkalis. This also holds koixI 
for Uie ct)rrcs[njinliiis ;S-couipoumU, wluch are not »>blaiii«l by th» 
direct action of halogpnfi upon naphtlialciie, but can be pn-parpd 
from othtT ,'3-coiiip«mHl«, HUrh a.4 ainino-iU'rivalivi's, sulpho-dcrivtt- 
tivce, etc.. tn- thp iiu-tluHiN ilcvcribtHl under tx>n2cnp (303,4). 

874. The priHliK't nbtainei] by the action of conrentmtpd nitric 
arid upon naphthnlcnc is very inijxirtant for thr oricntatlnn of the 
naphthalruc licrivutivas: it is tr-jiUronaphtfialnic, SI.P. (il°, wliich 
is provwl to belong to the a-serios by its conversion into the same 
naphthol as is obtaiiio<l from piieiiylisocrotonic acid (370). 

ThL' position of th»? substiluents in a preat numbor of mono- 
siil)«titution-product!4 can i>o determinix] from a knowlodgt; of that 
of lilt* nitro-group in this nitn_maphihak'ne. for the mtrcv-group 
can lio reUucerl to an aniido-groiip. which is rcplatfable by numerous 
atoHia or groups by means of the dittzo-a-action. If a monosub- 
stituted naphthalene is known to be an n-coinpound, iis i!«»mcr 
must belong to the ;'?-flnrip,«. 

378. On heating niiphthalpne with cnncentrated sulphuric acid 
at a temperatun* not excw^^ling Sif, the two isomeric miphthalene- 
monosulphonic acufs are fnrmrd; nt IfWonly the,.9-acid b obtained 
owing to the conversion nf the a-cnmpound into its,?-i80iner. Btith 
arc erj'Htalline, and vcn,- hygmjicopic. 

On fusion with caustic potash, the nnphlhalenesulplionic arida 
are convened into ^)il}ihtl>u^li.C^„H,■OH, with properties very similar 
to thow! of phenol. They art* presenl in eoal-tar. a-.\'/ipAMof 
melts at il.i*. and lioits at 2S2*: /i-naphlhot melts at 122*, and boil« 
at 2^". 'Hie hydrti.\yI-group in lhcs(« r(ini|M)UndK can be replaeod 
much more n-adily ihun that in phenol. They di.ssotvp in alkalis. 
With ferric chloride /r-niiirliihul yields a flocculent, violet prrcipi- 
Ite; /9-uaphthol gives a green colouration, and a )>recipiiatc i»f 
^ff-dinopftihol, H(J-C,nH,-(",„na'OH. ITie violet precipitate obtained 
with a-uaphtliol is |3os«b!y en iron derivative of a-dinaphlhof. 

376. a-\aplith>jfaminr. and ^^-napfitlDjlammt. C,yH,XTrj, eon 
bo obtained by the reduction of the corresponding niltu-detivalives, 
but are usually prepared by heating o--na])h1hol and ^-naphthol 
n^peetively with the ammnnia compound of xinc rlilortih- nr of 
-alcium chlori<ie. rt-Xaphlhylaminc la a solid, melting at StTYond 



SUBSTITUTION-PRODUCTS OF NAPHTHALENE. 475 

has a faecal odour; /?-naphthylaminc melts at 112°, and is nearly 
odourless. A mode of distinguishing between tlie isomers is afforded 
by the fact that the salts of the 'f -compound give a blue precipitate 
with ferric chloride and other oxidizing-agents, while those of the 
/^-isomer do not. 

These bases are of technical importance, since the dyes of the 
congo-group and the \)enziipurpurim are derived from tliem, and pos- 
sess the imjwrtant property of dyeing unraortlanted cotton. 

Congo-red is formed by diazotizing benzidine, and treating the 
product with a sulphonic acid of naphthylaniine; the dye is the ao- 
' dium salt of the acid thu» formed : 

H,NC,H.— C,H,.XH,->aN,-C,H«— C,H,-X,a + 2C„H,<|^^-> 

Beultllne BenzitlLaedlazcinlum chloride NaplilhytamiiiesuJ 

plioiiii; acid 

CuDgo-red 

The acid it&elf is blue. 

The benzopurpurins differ from congo-red only in having a 
methyl-group attached to each benzene-nucleus of the benzidjne- 
group. 

377. Some polysubstituted naphthalene derivatives may be 
mentioned. 

Dinitro-a'Tiaphthol is obtained by the action of nitric acid upon 
the monosulphonic or disulphonic acid of 'f-naplitliol. Its sodium 
salt is Martius' yellow; it dyes wool and silk directly a golden- 
yellow. Nitration of (c-naphtholtrisui phonic acid yields dinilro- 
naphtholsulphonic acid, whose p<:)tasMiuni salt is naphlhol- yellow; 
it resists the action of light better than Martins' yellow. 

Naphlkionic acid is one of Jhu longest known naphthalene deriva- 
tives: it is I'.^naphthyluminesiilphonic^dd, 




NH, 

and results from the interaction of a-naphthylamino and stdphuric 
acid. It is crystalline, and only slightly soluble in water; it is 



476 



ORGANIC CHEMISTRY, 



manufactured for the preparation of conRo-rcd and other dyea. 
Sohitiors of its Bailw liiRplay an iiitrnat; n-ddisii-blue fluorescence. 

a-Naphihaquinone, ^.',^,lUO,. i? formed by the oxidation of many 
tf-dcrivativf-B, and of sonic diderivativos, of naphthalcnp. It is 
usually prepared from naplithaleiie it«e]f by oxidation with a boiling 
fiolullon of chromic acid in glacial acelic acid, a motliofl of formation 
which has no parallel among lliose for the preparation nf thr mr- 
reapriiding benzene derivatives. It rr>'stallize3 from alcohol in 
doep-yellow noodlca, melting at 125°. It resembles benzoquinonc 
not only in colour but in it« other profwrties; thus, it has a char- 
acteriiitie, pungent odour, and is very volatile, eubtiniing readily 
at 100" ; it is easily reducetl tu a dihydroxynaphthslene by sulpbur- 
ous acid. For these reasons the structural formula 








H 
J 
U 



is assigned to it, analogous to that of benzoquinonc. In support 
of this view is the faet that on oxidation it. yields phthalic acid, 
proving both oxygen atom-s to be attachecl lo the same ring: more- 
over, hydroiylamine converts it into an oxime. Knowing the 
cnnstitution of a-naphtharininone ta be 1:4, it is possible to deter- 
mine that of other diderivntives. If, cm oxidation, ihey yield this 
quinone by elimination of the substiluents, the latter must occupy 
thcpflra-position. 

{i-Saphtkaqitmnne, CjoHaO,. is formed by the oitid&tioQ of atnioo- 
naphthol ( 1 : 2"' which proves its structure to be 




O 



o 



Its properties arc very different from those of the «-quinonc. It 
crystalliiefi in red ncetUes, and decomposes without melting at 115®, 
being therefore noti-volatile; it is also odourless. Sulphurous acid 
reduces it to 1 : 2-iiihydroxynaphthaleue. 



ADDITION-PRODUCTS OF NAPHTHALENE. All 

Addltion-produoti. 

378. Naphth&lene and its derivatives yield addition-products 
somewhat more readily than the benzene derivatives. The best 
known are those formed by the addition of four monovalent atoms, 
such as hydrogen or chlorine. It has been proved by the oxidation- 
method, and in other ways, that the four atoms are always added 
to the same ring. 

On passing chlorine over naphthalene at ordinary temperatures, 
there results naphthalenetetracfUoride, 

H Ha 

hOO-' 

H HCl 

a well-crystallized, colourless substance, melting at 182°. On 
oxidation it yields phthalic acid, and is converted by alcoholic 
potash into dicMoronaphtkalene, CioHgClj. 

On reduction with sodium and boiling amyl alcohol, /?-naphthyI- 
amine yields a tetrahydro-derivativc, C,oH,,NHj, a compound with 
most of the properties characteristic of the aliphatic amines: it is 
strongly alkaline, absorbs carbon dioxide from the air, has an 
ammoniacal odour, and cannot be diazotizcd. All four hydrogen 
atoms are in union with the same ring as the amido-group, 

H H, 






H H, 

ance, on oxidation with potassium permanganate, this substance 
is converted into o-hydrocinnamiccarboxylic acid, 

p „ .CH,CH,.COOH 
^»"*^COOH 

which must evidently result from a tetrahydro-derivative with the 
above structure if the oxidation takes place at the C-atom linked 
to the NHj-group. Moreover, the hydrogen addition-product does 
not take up bromine, another proof that the four H-atoms are 



47* 



OflG^NfC CHFMISTRY. 



atteched to the same bcniPQe-nucleUB. The entrance (rf two liytlro- 
gen atoms int^) eiLch ring niuitt produce a compound with double 
boncb, which woiilcl yield an addiliou-product with bromine. 

The cinnplctr irKcniblancc Ix-twifn /?-t<'trahy(iroiiaphthylttmine 
and the aliphaltp atnitiPB is anttthpr conliniiatiou of the view that 
the ring-stnioture does not in itself occasion any marked peculiarity 
in the chfiiiical prnpi^rtips of a compound (262). This compound 
may lie looked iipoi! as benxene with a saturated side-chain, 
—CH, ■ CH, ■ CII(Nir,) ■ CK,—, linked to two orfAo-C-atonia. 

o-N'aphthylaiiiiiic ran alw> 1>l> reduced by aniyl alcohol and 
Bodiiun, but the tHrahydro-dmvative formed is quite different 
from that ohtaincil from ;?-iiaphtliylaniiiie, for it possesses all the 
propertieif characleriatic of llie aromatic amines: it can bo diaxo- 
tized, and lia* not au ammoniacal odour. Since it, too, docs not 
form an additioa-pirieluct with bromine, its constitution is 

fl. . B 




This proves that the four hyiirogen atoms in it also are in union 

with Ihe same nucleus, but not the one linked to the aniido-group. 

In support of tlus are iu completely aromatic character, and the 
hfact that, on oxidation with potassiuiit pennanganate, the ring 
■" containing the arnido-group is removed, with formation of sdipic 

acid CIM), 

CHa 

/\ 
CH, COOH 



CHjCOOH 
CH, 



Tetrahydrv-a-naphtkjflaminf must, therefore, bo looked upon as 
aniline contfunins a saturated side-chain, — CHj-CHj-CHj-CH, — , 
linked to two ort/i*>-C-al«m3. 

n. AllTH&aCEirE. Ci,Uia' 
379. Ardhracenc is present only in small proportions in coal* 
tar, the percentage varying between 0-25 and 0-*5 per cent; 



ANTHR/tCENE. 479 

* 

notwithstanding this, it is the basis of the manufacture of an 
important dye, alizarin (388 and 383), 

By fractionation of anthracene oil (287), the so-called "60 per 
cent, anthracene" is obtained; this is mixed with one-third of its 
weight of potassiiun carbonate, and distilled from an iron retort. 

O TT 
This removes certain impurities, among them carbazole, ■' * > NH, 

C.H, 

which is present in considerable proportion in the crude anthracene, 
and is thus converted into a non-volatile potassium derivative, 
(CeHj),N ■ K. The distillate consists almost wholly of anthracene 
and phenanthrene, which are separated by means of carbon 
disulphide, in which only phenanthrene is soluble. On crystalliza- 
tion from benzene, the anthracene is obtained pure. 

It crystallizes in colourless, glistening leaflets, with a fine blue 
fluorescence; it melts at 213°, and boils at 351°; it dissolves readily 
in boiling benzene, but with difficulty in alcohol and ether. With 
picric acid it yields a compound C„H,,-CjH,(NO,),OH, which melts 
at 138°. 

Various modes of preparing anthracene are known which give 
an insight into its constitution. One of these is its syntheas 
by AfJscHiJTz's method from benzene, aluminium chloride, and 
tetrabromoethane ; 

BrCHBr /CH\ 

C,H,+ T +C,H,-C^/T >C,H, + 4HBr. 

BjrCHBr X;h/ 

This proves that anthracene contains two benzene-nuclei imited by 
the group CjH„ a view further supported by its formation on heat- 
ing o-tolyiphenylketone with zinc-dust: 

From this it follows that the CjHj-group is linked to ortAo-C-atoms 
in at least one benzene-nucleus; the formula of anthracene may, 
therefore, be written 

()l^«>O.H,. 



48o 



ORGAmc CHEMISTRY. 



The central group C,II, U also linked U> orlho^-a\cms in the aeeond 
beiiKene-nucIciiB. This ie proved, for example, by the synthesis 
of anitirnociip from o-lmmHibonzyl hmmido and fiodiuiii. in which 
a diliydrtxJorivattve Li first fcirnieti, awl ifi ri-adily converted itito 
anthracene bv oxiiialion : 



a 



jBr Na, Br| H^ 



CH,[BrNajBr 




»3rcinM(benirl liromlil* 



CH, 



4Nanr + 



CH 




-2H 



CH, 




CH 

AntbrscviK 



This conatitiitioii Indii-ateR that niithracene should yield a very 
larfie mimljor nf is(inn?ric mibstilulion-pro<lucts, that of the mono- 
subHtitutiftQ-pnxlucta being three. N'lmiberiug the carbon atoms 
thus, 




then I •= 4 = 5 = 8, 2 = 3 = 6 = 7, and 9 = 10. Fifteen dtEuiv 
stilulion-products with similar grt)ii[w are jmssible. A verj* cotiaid- 
erabte nunilxT of anthnu-rnr derivatives is knmvn, ulthmigh it is 
small in comparifton wit.h the t-jiormoiis number theoretically 
possible. 

The orientation of the anthraecro derivatives is effected simi- 
larly lo llwfie of riaphlliaU-iie (372), uxidatiuu and a study of 
resulting product* being an important aid. '^ gl 

Sulxtitntion-piodactt. 

380. Anthraqurnone, C„H,Oj, Is one of the most impor 
derivative* of antbraeene, from which it is obtairietl by oxidation 
with snch agcnlts &s nitric and chromic acids. Authrareiic is so 
readily converted into anthraquinooe by nitric acid that it is not 
possible to nitrate it. 



ANTHRAQUINONB, 48 1 

Anthraquinoixe is proved to have the struetiire 

CO 




CO 



since it is formed by the interaction of phthalic anhydride and 
benzene in presence of a dehydrating-agent such as aluminium 
chloride: 

C.H,<gg> |0 + H, |C.H, = C^<gg>C,H«+H,0. 

Fhtballc aubydrida 

This reaction takes place in two stages: o-benzoylbenzoic acid, 

CO- P H 
CeH,<p„^j} *, m first formed, and loses one molecule of water, 

forming anthraquinone : 

CO 

C^./^CeH, - H,0 = C.H.<^>C^. 
X;00H ^^ 

Itl. The central group in anthraquinone can be proved to be in 
union with two o-C-atoma in each benzene-nucleus — another proof 
that the same \9 true of anthracene. The same method is em- 
ployed as in the proof of the constitution of naphthalene (US) : one 
of the benzene-nuclei is distinguished by the introduction of a sub- 
stituent, so as to identify the one broken by the oxidation. 

On treatment with benzene and aluminium chloride, bromo- 
phthalic anhydride reacts like phthalic anhydride, yielding bromo- 
(mikraquinone by elimination of water: 

I CO " I ' « 

Br.C^,<S>0 -» BrC.H./'^C.H. -> BrC.H,<^>C,H,. 

Bromoan ibraqulnatie 

Since thia compound is derived from phthalic acid, the two 00- 
groupe must be substituted in the or(Ao-position in nucleus I, Its 
Br-atom can be replaced by a hydroxyl-group, by heating with 
potassium carbonate at 160°, and the kydroxyanthraquinone thus 
fonned oxidized by nitric acid to. phthalic acid, the formation of 



48> ORGANIC CHEMISTRY. 

which {troves aucloua II to li&\e been unacted upon, aad to be alM> 
substituted in the orthO'^tmHoia: 



U 



u 



HOCtH|< (Y%'**'t"» HOfTl^ • •' 



PbiluJi«Hid 



The constitutional rormuln or unthraqiuitone indicates that onljr 
two isomeric morniFiibslitiition-prodiicts are po»iible, This has 
been verified by eKperimeiit — a further proof that the formula is 
correct, 

382. Anthraqmnoiic cr>'St&IUzcs from glai-ial lurctic arid in light- 
vrIIow neodlt'S, mcltinK at 277°, At higher teinp<TatiiiTa it sub- 
limit very readily, foriiiinK '"UK. sulphur-yellnw prisnis. It is vcr>- 
stable, and is not easily attacked by oxidiBing-ogents, or by con- 
centrated nitric or sulphuric acid. 

The name Rwihraqmntme is in snmo mensiire ineorroct, for this 
substance lacks some nf the pro|KTties characteristic of quiuopcs, 
such as ready reduction, great volatility, pungent odour, etc.. aud 
has much more the charanter r>f a diketnnr. M'ith fiised caustic 
potash it yields benzoic acid, and with hydroxylaniinc an oximc. 
On warming with zinc-dust and caustic-soda solution, it forms 
ioanthraTuA, 

CHOH 

which in alkaline solution is converted into anthraquinone by atmo»> 
pheric oxidation. Oxaiilbronot dissolves in alkalis, the solution 
having a deep blood-red colour. 

This property of oxaiitlirunol makes its formation a delicate test 
for anthrafjtiiiione. It is carried out by wanninft the i<ubdtaQOC to 
1m tested will) Einr-dit5t and caustic-soda Holminn; IT nntliniquinone 
is present, a blood-r«l colouration is developed, and in destroyej 
by shaking up the mixture witli air. 

Oxygeii is rendered "nctivo" (8M) in the oxidatioa of oxan- 
thranol, hydroRen prroiidc b»'ing formed in addition to anthraqui- 
noac. Afl in other instancea of oxygen being rendered active, for 
every atom of oxygen employed for oxidation, one atom i« used up- 
in the formation of hydrt^cn pnoxide. 



ANTHRANOL AND ALIZARIN. 483 

On reduction with tin and hydrochloric acid, anthraquinone is 
converted into anihrarwd, 

a substance of weak phenolic character, which is slightly soluble in 
cold, and readily in boiling, alkalis. Its formation is to be looked 
upon as resulting from the splitting-off of water from an interme- 
diate product, a dihydric alcohol; 

• *^C0 "^* ■ *^Ch|OH| '^^^ * W"4C 1 >t^sii«- 

AfithraquiDOnB 

AmnraDol 

When anthraquinone is more strongly reduced, by heating with 
zinc-dust, it yields anthracene. 

Alizarin, or dihydroxyanthraquinone, is the most important 
derivative of anthraquinone, and is a dye of a splendid red colour. 
It was formerly manufactured from madder-root, which contains 
a glucoside, rvberythric acid, C„HjgOn, yielding glucose and alizarin 
on boiling with dilute sulphuric or hydrochloric acid; but it is now 
prepared almost whoUy by a synthetical method. It is one of the 
or;ganic dyes known to the ancients. 

In preparing alizarin, the anthracene is first oxidized to anthra- 
quinone with sodium dichromate and sulphuric acid. Heating 
with concentrated sulphuric acid at 100° converts various impiui- 
tiea into sulphonic acids, the anthraquinone remaining unchanged; 
on dilution, these sulphonic acids dissolve, so that pure anthra- 
quinone is left after filtering. This is then heated to 160° with 
fuming sulphuric acid containing 50 per cent, of sulphur trioxide, 
the main product being the monosulphonic acid. Its sodium salt is 
only slightly soluble in water, and separates out when the acid is 
neutraUzed with sodium carbonate. On fusing with sodium hydrox- 
ide, the sulpho-group is replaced by hydroxj-l. A second hydroxyl- 
group is simultaneously formed, its production being considerably 
facilitated by the addition to the reaction-mixture of potassium 
chlorate as an oxidizing-agent: 



484 



ORGMMC CHEMtSTRY. 



,00. 



C^,<^>C3,SO^ft + 3NnOH + O => 

Sodium aii(Ikr»i|iil[iaDo- 

- C,H,<^>C,H,(ONa),'+ 2H,0 + Na^^ 



The dyo is set f roe from the sodium s*lt by ailditton of an acid. 

Alizarin crystallizfs in red prisins, and siiMimes in orange 
needles, mt-lting at 2Sl)''-290'; it is nearly insoluble in water, and 
sliKhtly Bolnbk- in alcotmi. Oti account of its phenolic character, 
it dissolves in alkalis. It yicldfi u diacctatc. <Jn distitlatioD vntii 
jsine-diLst. it is cwnvertwl into anthracene, a reaction which gave 
the fiisl iiisi^ht into the eonstitution uf nlizarin. 

Tlie value of alixariii as a dye depends upon its power of forming 
fine-culourei.1. Ini^oUihie compound-s, called iakts, with metallic 
oxidw. Wlien a fabric is mordant*fl with one of these oxides, it 
van Im* dytti with alizarin, the colour depending on the oxide used. 
The ferric oxide eoniptiuml of alizarin is violet-black, the chromium 
oxide coinpoinid claret-colour, the calcium oxide compound blue, 
the aluminium and tin eom|Hiuniis various sliaden of red (Turkey- 
red), etc. 

383. Hie method by whii;h alizarin is prepared proves it to be a 
<ierivativp nf anthraqiiinnne, but it haa now U» bii deterinincil what 
poKitiotw the hydrnxyl-Rruups occupy. The formatioii of alizarin 
when phthalic onhydri<le is heated at 1.50" witJi catechol and 
Bidplmrie arid proves lliom tn be in the same benzene-micleiis; and, 
since till- liydroxyl-groujw in catechol occupy the o-jxwition, tJie 
same must be true of alizarin : 

Phthkllc Auhydrldo Oalei-hal AN/nrtn 

It follows that the choice lies between the two structural formulffl 



PHENASTHRENE. 



485 



The result of nitration prov«s that fonnula I is correct. Two 
isomeric niononitro-derivalives are oblained, with the nitro-proiip 
in the same micleus as the hydroxyl-groupe, since both can bo 
oxidized to phlhalic aeitl. Foimula 1 alone admits of the formation 
of two such mononitro-derivatives. and must therefore be correct. 

Other liydroxyl-dt-riviil ivfs of snihrnqninone nrp nlxo dyes. 
This ifl so only when two hydroxyl-groups arc in the o-po»ilion to 
one anothpr. In addition to these, derivalivts of anthraquinon* 
cnntainitiK liydro\yl-gri>ijp8 and amido-Kraups, or only amido- 
groups, are also valuable dyes. 



in. prekahth&ekg. o„h„, 

384. Phfn'fintkrene is isomeric with anthracene, and is present 
with it in "anihracene oil,'' they arc sppsratrd by the nidhocl 
already drei-ribcil (379). It crystallizes in colourk-ss. lustruus 
plates, which dissolve in alcohol more readily than anthracene, the 
solution having a blue fluorescence. It melts at 90% and boils at 

On oxidation with chromic acid, it yields fiiat phenanUira- 
j^ijMne (p. 486), anil then diphcnic acicl (3W), 

Tliis proves that phenanthr^'ne poswpssfs two benzene-nuclei directly 
linked to one annthor, and is thcrefdro a diphrnyl derivative, and 
also a di-ort/io-coiiipfHind. Uiphenyl with two hydrogen atoms 
substituted, — C„ll,t'nH, — , or — C,.H, — , differs from phenan- 

i thrent by C..H,. This must link together two (^-positions, 30 that 

L phcnanthrcne has the constittnion 

L This 



/ 



This structure finds support in the conversion of atilbene into 




486 ORCAmC CHEMISTRY. 

pKenanthrene, on passing its vapour through a K-d-hot tube, a 
method of forinati{>n analogous to that of iliphonyl from benz- 
ene (361): 

CH-CJl^ CH-C,H, 

\ -H» = T| I . 

CH-CeH, CH-C^. 

8t II bMiH PlieiiaaUiriina 

It is seen from the above const it iiticmal fammla that the group 
CH : CH, which is unitcil with four C-aloiiis nf <Uphriiyl, Uius yiehls a 
fresh ringofsixC-atoiiis. Thi; question arist'S whclhrr thin Ih& tnir 
bcnzcnc-rinf;; if it is not, the link C,H, must bo assumed to contain 
B dttiible bonJ. This ciiicslion is diEficult to answer. On tho one 
liaml. phpnanlhrpne displays aromatip properties; for example, its 
yielding phenanthraquinone. which resembles other quinones in 
being reducal by sulphurous acid to dihydroxyphenanthreoe, 



C,H,— C-OH 

II 
.— C-OH 



C.H.- 



the existence of a hrnmophenanthrene. in which tlie bromine 
atom is very firmly Hnkr-d, and is nut attaclced by alcoholic potash 
at 170*. and whose structure \s proved by ita oxidation to phenan- 
thraquinone to be 

C,H,— CBr 

I II ; 

CaH— CH 

and the fact that phcnanthrcne is not acted upon by Baeyer's 
reagent for double bonds (123): aH point to the aromatic character 
of this ring. On the other hand, however, the ^loup C,H, adds on 
bromine very readily, and is attacked when pheiianthiene is oxi- 
diaed — reactions characteristir of an ordinary unsaturated group. 

C„H— CO 
Pkenanthraquinonf, \ | , is a ytllow, erj'Stalline sub- 

C.H.-CO 
Btonce melting at 200^, ami boiling without dernmposition above 
360*. Its (likelonic chaiat'ter folltms from its yielding dideriva- 
tivcs with sodium hydrogen sulphite, and with hydroxy lamine. It 
b odourless, and non-volatile with steam. 



FLUOMNTHENE, PYRENE, AND CHRYSENE. 



487 



IT. TLTTOXAiriHSirB, FTBSHX, AXD CEB7IBHX 

3tS. Other hydrocarbons possessing condensed rings and a 
greater number of carbon atoms are also known. Among theae 
are fiuoraTilhene, C,,H,u with the formula 



pyrene, Ci^i^ with the probable formula 




and chryaene, Ou, H,,, with the formula 

C,H4— CH 

CjgHf — CH 

These compounds are present in the coal-tar fractions coming over 
above 360°, and also in a peculiar substance called "stubb-fat," ob- 
tained in the distillatioa of mercury ores from Idria. 



HETEROCYCLIC COMPOinfDS. 

S88 Hie compounds hitherto conddorpd all contain a ring of 
i.earbon atoms only, aiul can be cla!*siil tof;i'tVier under the name 
Ihomocifclif conjpouiKls, It was ineiitioncJ in 259 that riug-systeros 

arc also known posseesing not only carbon atoms but also those of 
k other ek'ments. Sulwtances rnntaitiing ring? of this kind are rlaJ<»('d 
' together aa hticrocyclie compounds. A few of these and their <leri\'a- 

tives will be considered. 



I. FTBIDINE, CjH.N. 

Pyridine and some of its homologues arc eonstiincnts of coal- 
tar. On mixing the*'liglit. oil" (267) with Bulphnrie acid, they 
absorbed by the latt{>r. and separate on nddiiion nf }>ndiuni rar-^ 
bonatc in the form of a dark-brown, basic nJI, from which pyridine 
and its homolognrs are obtained liy fTartionaJ diiil illation. Pre- 
pared by this method, pyridine is never quite pure, aliiv'a>'S con- 
taining small proportions of ilH homoloj^ies. 

Another source of pj-ridine is " Dippel's nil ," a liquid of extrpmely 
diaagroeabie odour, obtained by the dry distiltalion of boneu nhieh 
have not been deprived of their fat. It is a very complicated sul>- 
6tance. contnining. in addition to the pyri<line bases and qiiiitnliDe, 
many other nubatanccs, nucli as nitriles, amines, and hydrix-arbons. 

Pyridine is a colourless ltqui<l boiling at Ilo^, and with a spes:ific 
E|gravily of 1 0033 at 0*; it is niiseible with water in all proportions, 
has a strongly alkaline reaction, and a very charaeieriKiic txlour 
reminiscent of tobacco^moke. It is very stable, being unattaeked 
by boiling nitric or ehroniic acid. It reacts with siilpbnrir a*-id 
only at high temperaturt?3,yieUlij)gasu)phonicaeid. T|r- halngens 
have very slight action on it. On very energetic reduction witlt 
hydriudic acid at 300°, it yields normal iM'nlani' and ammonia. 

Being a base, It yields sails with aeiiis, mostly rea<Hiy soluble in 
water. The forrocj'anide dissolves with dlfliciilly, and Is employed 
in its purification. With platinum chloride, tbc hydrocblorida 

488 



CONSTITUTION OF PYRiDINE. 



489 



yields a double salt, (C(ngN)^I,rtCl„ freely soluble in WAtcr. On 
boiling this solution, two molecules of hydrochloric acid are clinii- 
naled.wilh produptioii of a yellow compound, (C4H(N),rtCI„whidi 
K niily slightly H>]uljle in wat«r; this reaction affords & delicate test 
for pyridine. The following test is also vpry delicate. On warm- 
ing the base with methyl iodide, an enet^tic reaction takes place. 
»nth formation of an addition-product, CjHjN-ClIgl, When this 
is warmed with solid potash^ it givca ofT & vcr>* pungent and dia- 
Sgrecable CHluur. 

387. Many tnt-thods for the synthesis of pyridine and its homo- 
logufs an; known, although but few of these afford in«ght into its 
constitution. Among them is the formation of pyridine from quino- 
lioeaiid [x-ntamotliyIenediaminc(182). When the hydrochloride of 
tho latter is gubmitted tu dry distillation, piptridine, or hexahydro- 
pyridinp, is pniduced, and can be oxidized to pyridine by heating 
with sulphuric arid : 

H 
XH.CH.NHHJICI XH.-CHj. >CCH 

CHZ |— -»Cn< >NH-.HC< >N. 

^CH.-ClLiNH, -Vn,-CH/ ^CCH 

Another metho<l of preparing pyridine, which is carried out at 
low temperatures and. therefore, afftinls even more t ruslwiirthy 
evidence of its constitution, is from '-chlomamylamine; when an 
aqueous solution of this substance ie healed on a water-bath for 
some time, it is transformin] into the hydrochloride of piperidine: 



/nj .^^H| — CH, — CI 



••ClilorMi my kuiiio 



'C".<ch;::?h;»^'«'Hci- 



f-Chloronmylnmin«» wa« thhs obtained by GABRtet. ^-Clilofo- 
propylphfnyl tithcr, obtriiDi-d from chloro trim ethylene bromide and 
eodiuin phenoxide, rvactu thus wit It sodioinaloolc ester: 

C,H,0 CH, Cn,CH,a + NaCH(COOC,Hj, - 

- C^iO-CH,-CH,CH,CH(COOC',H,),. 

On saponilicatian of this ester, and subsequent heating of the acid 
obtained, ODS molecule- of earhon dioxide is epiit off, with formation 
of «-phei>oxy%-aleric acid, C4I(0'(CH^,.CO0H. When tJiis acid 



•49° 



ORGANIC CHEMISTRY. 



Is liHt«d vith iMd thioe]rftn«t«, It i« conceited into tboeorrMpond- 
ing Dttrile. C»tIO-(CII,),.CS, which is reduwd by BoJiiim atwl 
alcohol to •-phenoxyam}'! amine. C,HjO-(CH,),-NH,, On hoftting 
with bydracliloric acid, the phenoxyU group Jn ibii amine ix replaced 
by chlorine. 

Since pyridine is coidly redu'ccd to pipcridinc by sodium aud 
olcliohol. and pip«ridiuc can be oxidized to pjTidine, it may be 
assumed that pyridine has tlic s&me clos«d chain as piperidiae; 
that Is, one of five C-atoius and one N-atora. Moreover, iljcan be 
proved iliatthe N-atom in pyridine is not linked to hydrogen; for, 
while pipcridinc I)08S«S3C3 the cliaractcr of a 3econdar>' amine, yield- 
iiif. a, iiiiniso-derivativi; for example, pyridine hoe tliat of a tcrtiarj- 
amine; thus, it yields an atIdition-product%\-ith methyl iodide (386), 
ami the iodine atom in this substance, like that in other an^monium 
iodides, can be cxchan^d for hytiroxyl by means of moinl silver 
oxide. 

The number of iwjnieric subetitutJon-products, like that of 
benzene (263),. indicates that forh rarhon, atom is in union tcUh one 
hydrogen atom, A substance of tlie formula 




should yield three monosubstilution-prochMrts, 2 — 6(a), 3 = 5((S), 
and i{y). Moreover, for aimilar dubetitueots, eix disubslitution- 
pHHlurUi are possible: 2:3-6:5; 3:4 -5:4; 2:4 - 6:4; 2 :6, 3:3, 
and 2:5 = 6:3. Tliis agrees with the results of experiment. The 
mode of linking of thno oiit of the four valencio-s of each carbon 
atom is thus established, and that of two of the three nitrogen 
valencies; it rcmainK only tti determine how the f<nirth valency of 
each carbon atom and the third of tiic nitrogen atom are distributed 
in the molecule. 

The same argumcat wliieh led to the asauinplion of the centric 
formula f<ir l>enzcne (2M) am applicable here. The great stabihty 
of pyridine towards energetic chemical reagents proves that it does 
not possess flnuble bonds. Further atialngica with b<!n;(rne support 
the aaamnption of a similar comstitutJon. Only the side-chains of 



I 



PYRIDINE ASD ITS HOMOLOGUES. 



4»l 



both compounds are attacked h}' oxidising- agents; nith sulphuric 
ai'id, both jield sulphonic acids, which are coiiverttd by fusion with 
caustic potash into hydtnxyKIcrivatives, and by heating with 
jjutassiuni cyanide into cyaniilea. The hydroNyl-derivativcs of 
pyridine have a phenolic cliaracter: they yield characteristic colour- 
ali'ins with ferric chloride. The OMistiUitioQ of pyridine must, 
then-fore, bo 

CH 




'A 



bckS/CK 

N 

It muil be lookfd upon at benzene in wAkA »ti« of th( CH-grouj>s nas 
been rcplacfdbij'S. 

NotwithstaiidtiiR these nnnlogii^, thfrc are great differences in 
tlio l>ctinvi(Mir nf bcnienonnd pyridine, one of thorn iwing thnl pyri- 
(litiL- doi-s not udnilt of nitnition. 

The principle of the oriontatioii «f p>Ti(iiae is the same as that 
f)f b<'nzene — cimversioii of a compound t»f iinknuwn gtmi-tiin" iiit<i 
one with its sidt'-fhainK in knoivn ptisitioiis. The nKinotiarbnxylic 
and diipaxlxixylic arids have acni'cd as the mam basis for its orienta- 
tion: the iiiclhod of o.srtTtuiiiin(i llif portions ocrupii-d by the 
carboxyl-groupa in tht-ae conipomuls ip described in 890. 

Homoto^ufrB of Pyridlae. 
388. The honiologues of pyridine are the methylpjiidines or 
picolinee, dimethyl pyridines or hiiidinea, ai.d trimethylpyridincs 
or caUidi.nf9. Many of them can be obtained by more or less com- 
plex methods; thus, ^-picoline is formed by the distillation of 
acroleiR-ammunia (M7), and eollidiue by the JistiUation of eroton- 
aUlehydivaimiionia. Tliw furtnalioii of pyridine and its homohiKiies 
by the drj' distiltation of bones depends upon these reactions; under 
the influence of heat, the fat present yields aL-roIein, wlilcb reacts 
with the annnonia n-aulting from the heating of the albumins, 
forming pyridine buses. 

Hantskch has diaco^'ered an important syntliesis of pyridine 
derivatives — the condensation nf one molecule of aldchyde-AJiamoua 
nith tn'o molecules of acetoacetic eater: 



493 



OKGANIC CHEMISTRY. 



CH,i 



K. 



o<!h 
c^,oocch, ch,cooc^, 

ch,.co coch, 

HNB. 
CH, 

aH.oocc^ ^CCOOC,H, 

II + 3H,0. 

,CCH, 

H 
I>Ili]n]nwi>llidlne<lk«rlKnqtllc Mt«r 

On oxidation Willi iiitmiitt ni^id, tSiiii .>(ubstAnce loses two Tl- 

onv from the CH-Kn)U|i hikI orn- from Ww NH-group, with foiDHh ' 

lion of eollkiiiu'dK'urlKixylii^ clliyl t'stcr. On capon i fie at ion of Mm 

wtlh caiutic tmbu;<h, and HubsiM|ucnt hi-jititig of the potusaium salt 

with quickliniv, tJi<! carboxyl-groups ure B|)lit off, and coUidinej 

a 

distils over. 

In lliia sj*Ti(hp*ii» lUTtAlilntiyde may be n>plaecd by other 

hydfe.and aci-toauctJL' i-wttT l)y the vstnTs of ctthrr ;3-ketonic &cid> i. 

that it affords a nH'tiKxl of prc|>!tririg iiuiiutuu» pyridine dcrivnlivw. 

Some of the honiologULW of jjyridine can lie oblaineil from it bv 

the action of an alkji iodido, an ailditioti-proUuct Ixrinjir formed 

On Iitatiiig this to 300°, the alkyl-group becomes detached from 

the nitrogen atom ami links itself to a carbtm atom a n-action 

fcuuluiious lo the forniation of tuluidiiie by hi^athig luethylaiiiline 

hytlrochloride to a high t-cmperaturc {285) . 

a-AUylpyridinr » of tiieurptical imporUincc. Laden-duro et 
tained it by the mndeiisaticm of a-picoUne with acetaldehj-de • 

NOU, CH, + OCHCH, = NC^H.-CH: Cll-CH + HO 
By iU Hid he effected the first synthesis of a natural alkaloid, that A 
coniiiw'.C,H„N(40S). «.AllyIpyrKhno was reduced with sodii-' 
and boiling alcohol, yielding "-pnjpj/pipcrid-iTi* 

H ' 

NH 



DERiyATiUBS OF PYRIDINE. 



49S 



whicli dUTcra only from aatural coruTae in being opiirally inactlTe^ 
whereas ihc alkaloid is optimally active. Tliis sulislanc-c was re-- 
solved into a dPXtro-rotator>' and a In-vo-nrtBlory miKlificatJon by 
fractional frystallizfttioTi of its tartralc. the dcxtro-rotalory isomer 
pniviiig Ui lit* identical with natural coniine. 

TTie conslitutionBl formula of this eompouml indicates that tlie 
carlwn atom in iinimi with Ihp propyl-gmiip is awmnieiric. ,^-Pn>- 
pylpiperidinc and >'-propylpiprridinc do not contain an aH>'mmetri(? 
carbon atom, ard should tlirifforc \k optically inactive, which is a 
proof of the 'f-stnicture of coLiine, as well as of picoline, from which 
lit is deriv<-d. A further proof i« tlwt coniTin? KpUUi up into animonia 
d normal oetaiio when strongly heated with liydrioilie aeid. 
us treated, a ^-propyl pi jjeridiiie or ^--propylpiperidine luust 
yield an octane with a branched side-chain. 

Pipcriditif 15 |)rcscnt in pcppiT in combination as piperine, 
C,,H„NO,; on bailing; with alkaJii^, it yields piperie add, C„H|„0«, 
and pi|ipridiiir, liy addition nf one innlcnilc of water. Pipcrine 
miixt, thi'H'lorp, ho looked upon as a substituted lunidf^ of pipcric 
aeid, fontaiuiiig the piixiridine-reiiidiip, C\H,(N — , inxtcod of tlie 
NKf^roup: 

(yi,^'-C„H,0.. 

Piperjdine is a eoluurktis liquid, boiling at 106", with a charac- 
teristic |top]xT-likn ndnur and strnnply marked baaic pnipcrtica. It 
ia beet obtained by tiie electro-reduction of pyridine. 



FyrlduieQarboxylia Acids. 
389. Three pyriditwmojwcarboxyiic acids are known : 







COOH 
N 

nci>lliiic ftdd M 



f^^COOH 
N 

KlooUiklc •«»<#) 



COOH 







N 

iKmlcollok *cld if) 



The orientation of the carboxyl-Eroups in these acida can be carriccl 
out as follows. It was stated in 388 that the side-chain in coniine 
occupies tlie ff-position. ')ii oxidation, this sulistanec yields picol- 
{iiic acid, by conversion of the propyl-group into a carlxixyl-groiip, 
and elimination of the six added hydrogen atoms. Kcolinic acid 
is therefore the n-carlwxylic acid. 



494 



ORGANIC CHEMISTRY. 



Niroiiiiic ncid is proved ia have the ^-constiLutioo thus: quino- 
Imc (395) ha« the formulii 




It is naphthalene in which onr of tlic rt-^II-Rrniips lias hrcn replaced 
by N. On oxidation, quinoliiic yields a pj-ridircdicarbosylic acid, 
quiwAinic acid, wliich must therefore have the structure 

fiCOOH 
•^'COOH 



On heating this acid, one moletule of oarbon dioxide '» eliminatM. 
with fommtioii of nicotinic arid. Since the carboxyUgroup in 
piailinic ai-iil lias been proved to occupy the *r-posiiion, nicotinic 
acid must be tiic /9-acid; there remains only the y-etructure tor 
isonicotinie iipid. 

The pyridincnionocftrboxvlir arids are formed by the oxi^lation 
of the homologues of pyriilinp conlmning a side-chain. Nicotinic 
arid derives its name frnin ius funriatuut by ihc oxidation of nicotine. 
The mnnocarlinxylic aridH art- i-rj-filidlinn, and possess both a basic 
and an acidie characlcr. As bases, they yield salt.s with acids and 
double salts with platinum ohioride and mercuric chloride etc ■ 
As acids, ihey fomi salts with bases, the copper salts bcine oftoi 
employed in their seporntion. 

Picolinic aeid can be dist Inguiahed frona its isomers bv tw 
prupertiea: on heating, it splits off CO, more rea^Hly than they d 
with formation of pyridine ; and it gives a ycllowjsh-red colouration 
with ferrous sidphate. Quinolinic aeid ans^vcra to tho Rame t 
it may, thereforf, be conclude*! that they are apiilicablo -to '■ ^ 
with a carboxyl-group in the flr-iJojdLion. 



1 



TOO. By Itie aid of thesy reactions it is possible to dptorminr t'hii 
positions of the carboxyl-KroUTw in the six PUritiinedicarhoxuliJ 
On hpatinp with Rlneial arotic ncid, dipicolinic arid B\A'tK « 
tnoleculu of CO,, funiiirig picoliDic acid; on healine al - ' 




PYRIDINECARBOXYUC ACIDS- 495 

two molecules of CO], yielding pyridine. It must, therefore, have 
the aH'-structure 



HOOc'v^COOH • 



N 

Quinolinic acid was proved in 8S9 to have the "^structure. LuHd- 
inic acid answers to the ferrous sulphate test, and, on heating, 
readily loses one molecule of CO,, forming isoQicotioic acid; this 
proves it to be an a7-coinpound, 

COOH 

.'COOH ' 

N 



Isocinchomeronic acid also gives the colouration with ferrous sul- 
phate, and is converted by heat into nicotinic acid. It cannot be 
the a^-oompound, this structure having been proved to be that of 
quinolinic acid, and must, therefore, have the ajS'-constitution, 

HOOC,^ 

l^COOH- 

N 

The positions of the side-chains in four of the six possible isomers 
have thus been established. For the two other acids there remain 
the structures pp" and fiy, 

COOH 
HOOC/NCOOH ^^j j^COOH. 

N N 

When strongly heated, cinchomeronic acid yields isonicotinic acid 
along with a small proportion of nicotinic acid; under similar condi- 
tions dinicolinic acid yields only nicotinic acid. They cannot be 
B-compounds, for they do not give the colouration with ferrous sul- 
phate; it may, therefore, be concluded that cinchomeronic acid has 
the ^-structure, and dinicotinic acid the pp* structure. 

391. Pyridine may be looked upon as derived from benzene by 
replacement of one CH-group by N. Other closed-chain com- 
pounds are known, derived from benzene by replacement of two 
CH-groups by O, N, or S, respectively. Such are furfuran, C4H4O; 
pyrrole, C,HjN; and thiophen, C,H,S. 



49* 



ORGANIC CHEMISTRY. 



n. FTOroBis, c,»,o. 

Furfuran, B.P. 36", is itsolf of liitle importance; two of its 
sub8titutiun-produ(.-l«> must be cnnsidi^red in some detail. 
To furfuran is assigoeil the ring-formula 

HC — CH 



Hi! h. 



V 

This is supported by tHp resemhlancp in properties between somo 
of its derivalives, such as juTJtimliiehjde (furfural or furjUTole), 

C,HjO'Cf:,aiid the correspond! nji iM^nzene derivatives. Moreover, 

the O-atom can l>r pmvc*! to Im- linkt^d similarly to tliat of ethylene 
oxitlt (ISei, sinn- nn trcatmrnt with soLliuiii. hydrogen is not 
evolved fmm furfuran, which pmvps (he absence of a hydroxyl- 
group: and stiipc it is not acted on by hydroxylamine or phenyl- 
hydrazine, which indicates that it does not contain a e&rbonyl- 
gnmp. 

Furfuran derivatives can bo obtained from thi? 1 :-l-dikctones, 
K-CO-CHj-CHj-COR, by trealownit with dehydratinji- agents, 
Buch as acetyl chloride. This reaclifni may be looked upon as the 
nwilt of the t-otiverslon of the dikclnnc into on unstable form« 
R-C;CHCH:C- R, which then splUa off water; 

OH OH 



"r<oiH 



- H,0 - 



HC=:C/^ 

Hc=c<; ' 

^R 



Tlufl method yields ^rt'-substituted furfuran derivatives, the 6- 
atonis ID furfuran being denoted a? in the scheme 



V 



M 



FURFURALDEHYDE. 497 

This syntfaeds of furfuran derivatives is likewise a proof of their 
constitution. 

The meet important derivatives of furfuran are furfvraldehyde, 

C4H,0-Cq, and pyromucic acid, C4H,0-C0OH, both of which have 

long been known. 

Furfuraldehyde is prepared from pentoses by the method men- 
tioned in 211. It has the character of an aromatic aldehyde; like 
benzaldehyde (299), it is converted by alcoholic potash into the 
corresponding acid, pyromucic acid, and the corresponding alcohol, 
fwfuryl alcohol, C^HjO • CH,OH : 







l^COOH ■** IJcHjOH. 
O O 

FortimldehTde Pjromuolo mcU Piuturyl aloohol 



With ammonia it yields furfuramide, (CjH^OjNj, analogous in 
composition to hydrobenzamide (299). Just as benzaldehyde con- 
denses in presence of potassium cyanide to benzoin (368), furfur- 
aldehyde under the same conditions yields the similarly constituted 

H 
jvTOln, C^HjO-C-CO-C^HjO. The resemblance in properties be- 

OH 
tween the two compounds is, therefore, very striking. 

Furfuraldehyde is proved to have the ar-structure l^ varoua 
means; for example, by its formation from pentoses (211), which 
may be represented thus ; 



HO H 



(^-CHOlH CH=^^ 



CH-C^ 



OH CR 



HO H 







PmiIom Parfimtdehyda 



Furfuraldehyde results from the elimination of three molecules of 
water under the influence of hydrochloric or sulphuric acid. It is 



■*98 



ORGANIC CHBMiSTRY. 



a colourless, oily liquid of ogrcciiblc odour, and boils at 162°. A 
\vi3t for it is described in 211. 

Ah its nainp indicatos, pyromucic acid is fonncd by the dry 
dlstUlatUm uf mutic acid (812, 6). It can abo be obtained by 
oxidiaing furfuraldeliyde with flttver oxide. It m crystalline, niclta 
ut i;i*2*, can be readily sublimed, and dissolves freely in hot water. 
W lien heated at 275° in a sealed tube, it splits up into carbon dioxide 
and fiirfnran. 

r'yniiinieie neid wholly \zc\% the charaeter of an arriniatic com- 
pound : its pru]KTties in no way ri^sfinbk* those of l)eiiz(jic acid, but 
are like those of the un.saturat«l fatty acids. Thus, it eaadly under- 
gors oxidation; it almost instacitaaLi»u«ly dcctilourizea Baeyeb'S 
reaKviit (123), and readily odds four bromine atoms. Hence, the 
distinguishing characteristics of the ber zone- nucleus are absent, so 
that the formula 

HC=CH 

I >o. 

HC=C 

COOH 

with two double bonds, must be assipned to it. 



' m. FTBBOLE. C.IItN. 

3'92. pyrrole is present in coal-tar, and in " Wppel's oU " (388), 
It is a colourless liquid of chloroform-like odour, and boils at 131*. 
The vapou"^ of pjirole and Us ilerivatives impart a carmine-red 
colouration to a wood-shaving iiioi.st('npd with hydrochloric acid, 
due to the formation of an amorphous substance, pyrroic-red. 
This is a delicate test for these compounds. 

Pyrrok* can be aynthesizt'd by distilling succinimide (169) with 
ziHc-dust, wliieh proves its constitution: 



j—CiY 

Suocioliii'i]'* 



L 



CH--cn 

I >NH. 

CH=CH 
Pyrroto 



Pyrrole derivativea are obtained from l:4-dikctones by t]-eat>- 
ment with ammonium acetate, a process analogou.s to the formation 
of furfuran dt^rivatives from these substaiuips (3dl): 



PYRROLE MKD TMOPUEN. 



499 



^f=*\[0H7H 



H 



M'Pyrrolft 



l:4-blkDiuM 



Pyrrole has to some extent the charactw of a secnndary amine. 
The hy<lri»p'n linkfii U> uitroKt'ti can be replaced hy [Kitas.viiini, wilh 
frimmtmii of poiassio-pyrrole, C\H(?JK. which n-afta with B.lkyl 
Iiolidcs, ockl chloriJea, etc., yicMiitg "N-subslHutior-proJiicta;" 
that IB, pyiTftle derivatives with siikstitiicntii in union with the 
N-fttnin. 

Pyrrole resemblpR lienReiie in properlips munh mom clnsdy than 
furfuraii tlors, h<^ing much mnrr wtnWe than the latter. As a result 
of this, it cliH-s iiut yifUl lulilitioii-prodiicls wiili halogens. On 
rciluctioii with ziiic-iJu»t aiiJ awlic aciii, htmrvi-r, it tuke£ up two 
hydrogen atoms, with foniiation of dikyelropyrrofc* or pifrroline, 
CjHaNII, which adds on two atonLs of bromine. This behaviour 
is ver>' like that of benzene and its partial Iy-liydrat<?d derivatives 
(870), For these and other reastjns. pyrrole is assumed to 
centric bonds, aad its formula l^ccomea 




IV. THioPHEK, c,n,a. 

393. Thiophen has the itioat aromatic character of the com- 
poundtt inentioncfi at the bugiiiiutig of 591. 

It i.4 present in the crude benzene obtained from coal-tar (267) 
to the extent of about 0-5 per cent.; if-s honiologues, thiololen or 
methylthiophen,and thioxm tir tliinethylthiophcn, are contained, in 
tolnene and xylene from the some source. 

"Tbo CnK»iCAL Socirrv or Londoh cmptnys tlir nuue dih^/dnprmU 
fortLe cam)ioun(l C.n,N, atul Utrahi/dropprroU for C,H,N. tn lli» nomeneU- 
lura of (h« (J situ.tN CsBWiCAL SociBTT tlji.- ccTrotpnadiDg toruB ftr< pgrrotiH 
uih] pt/rrolidiii. — TrahalatiML 



joo 



ORGANIC CHEMISTRY. 



Thiophcn WM first obtained by Victor Meyer by agitating 
eoal-tar benzene with anmll amounts of concentrated sulphuric 
acid till it c<'a»xl t/i give the indo-phimin rtiietitm, a blue eolouratiun 
with isatin (398) and concentrate<l sulphurie acid. By tluH tr^aU 
roent the ihiopben is converted into a sulphouic acid, from wbich it 
can be r^ciicrated by tlie a<'tioii of suix-Tlicatt-d stcain. 

Thicipheu can be ajnilheeized by vurioua innthod^, the most 
iporUuit bdjig the interaction of auccinic acid and pentasulphide 
'•flC phosphorus. On heatinfi a mixture of tiiesc substances, a vlgw- 
4]Ud reaction enaite^, carbon di.siilphide is evolved, and a liquid, eao- 1 
sisting chiefly of thiophen, distiU over. 

It is fl enlourlesfi liqni<i. boiling at 84", a temperature which' 
differs little from the boiliug-pnint of benzene (80-4*). It, lias S 
funt, non-characteristic odour. It is heavier than water, its 
•pedfic gra\ily being 1-062 at 23°. 

Bromine reacU) eMergetically with thiophcn, forming ehicSy 
dibromoihiajtiu-n, C^HgBrjS, along with a small proportion of tha' 
monobronwMlmv alive. 

The lumiologina of tiiiophen can be obtained by Fimo's syiw ' 
thi'.sijt (268) and by other melhods; for inatance, by hcuting 1:4- 
diketoiire with pentaxulphide of phosphonia, a mode of synthesis 
which proves the constitution of the tluophcu bomologuea. ThuSi , 
acetonylacctone yields dimelfiytthwphen : 



KCH, 
OH 
I •OH 
HC=C< 

\CH, 

(unatsulp funn) 



^ClI, 

u'-noMttirlUiicftbni 






Since, however, thinphen has all the protw-rties of an aromatic com- 
pound, it mu.st also \m BKiuine<i to posst-sa centric, and not double^ 
bonds, «o that it-s constitution i»i represented by the following scbema 
whicli also shows the mode of denoting the carbon atoms 



V' 



THIOPHBM. 



501 



ofl'-Dittlkyl-thiophens arc obtaiued from l:4-diketone8; the 
/J-alkyl-coinpoimris cAn be jireparwl bj' auotlier niethixl. It was 
etati^i (p. 500) that thioplien results from the interaction of suc- 
cinic acid and pciilasulpliitlc of phosphorus; 



H,C— OOOH 

nij-oooH 

BihcIbIohU 



H 



HC-Cv 

HC-C^ 
H 

Thloptteo 



■Rimilarly, a m<moalky)-siiccinic and symmptrical dialfcyl-succinic 
acid reapcctivdy yiu-ld a^-alkyl-thmphen and ft/?;?'-aIkyl-thiophcn: 



CH,CH-COOH 

crr,-cn-cooH 

BjrmiriaiTlwl dlniaih;]. 
•uoclnlo •dd 



CH,C-CH 

I >S. 
CH,-^'-€H 

llilLip'bBn 



Tho known strueturp of tliost- coinpouiuU pan Iw cmploypd ns 
a basis for the orientatioii uf \\w derivatives of tliiophen. 

The two monocarboxylic acids, U'thiopliencarboxylic acid and 
fi'thiophencarhoxylic acid, 



\JfX>Oll and 



iCOOH 



poseffs the remarkable property, when a cold aqueous solution con- 
taining both of them is crystalliited slowly, of forming a mixture 
which caiinot hv rosolvefl into its cmnponcnt^. On oxidiiiiip a 
mixture of n-lhiotolen and .J?-thiotolen, an apparmtly honioge- 
tieous acid is obtained: from its method of formation, however, it 
can only be a mixture of the cnrreKpfmdinE arids, 

Thiophmketonex am prepared by Friekel antl Crafts' reaction 
(288) ; thus, acetothienonc or a-thiinyilmefhylkctonf. C,H^-COCH, 
is obtained frmn aec?ty! chloride thiophen. ami aluminium chloride. 
These kptones are reatlily oxidijtt^d to ihiopbenearboxylic acids, 
a good method nf preparing these compounds. 

A thiophmaulphonic acid is also known; it is more easily fonned 



50J 



ORGANIC CHEMISTRY. 



thajt berizpiieeulphonic acid, u'tiich funiish^ a methtxl of popoTAlinf; 

tliiophpii and txfiizene (p. 500). On (liatillation with potassiuni 

cyaiinlp, it foniw the coirtspciiiding nitrilc; but XW siiJphogmup 

is not rxclianji^cil f(ir hydroxyl by fuHion with caiiMic potasti. It is 

possible, however, to obtain a tfiiopiicnpftcnoi by the ioteracUon of 

aminothiophen hydrochloride and aitrDiu'itcid, which, yields a 

NO 
nitrated hydroxyl-dcrivative, C4HjS<Qtj*. This compound greatly 

nfcmbles p-nitrophenol; thus, it dissolves in alkalis, yielding a 
solution of yeliDw colour. 

On vulatilizliig (hiophen in a curmit of air, and passing the 
rpsidtin)» gajwmus mixture into carefully cociled, fuming nitric acid, 
the principal product Is dinilrotltwjyfifn, altliough nufnonilrolhiophen 
is also fomicd. The tatter U a solid, meJttng at 44°, and boiling at 
224**; it haa au odoiir like llinl of nitrobenzene. On redurlion, it 
yields aminothiaphcn, or tMophtnine, wliich differs from aniline in 
being very (instable; it qiiiekly ehangi?8 to a varnish-like mass, but 
its hydrticliloridf is .stable-. It does not yield diazo-oonipounds, 
but rwiPta with benzentdianonimn elilori<le, fonning a crystalline, 
orange dye. 

Many other ttiiopKen derivatives have been obtained. chtrBy 
through the researches of ViCTon Meyer. The examples which 
have been cite<l siitfioe to indicate the great analogy subasiing 
betn^een the propertien nf thioplien and those of benzene. 



7. PTBA20LE. C,H,N,. 

894. Pyrarolr is obtained by the action of hydrazine, NH,-NH» 
on eiMchlorhydriu (l^SSj ; 



CHj— CH 

iCll 



H,N-NH|H 



CH— CH 

II II 
N CH. 



Hydrr^n is simultaneously eliminated, which Is effected by 
ploying excess of hydrazine; one molecule of this takes up *\ 
atoms of hydrogen, forming two molecules of ammonia. This syo- 
thesis proves that pyrnznle has the above formula, so that it n)ay bo 



PYRAZOLE. 



503 



regarded as pyrrole in whieh one of the CH-groupe dm been 

roplseod by N. 

It is crystalline, melts at 70*, aiul is very stable. It yields 
only a weak base, for its aqwous solution has a neutral reaction. 

Pyrazole itself does not give impoiiajit derivatives, but such 
arc obtained from a dihydm-prmkict, ptfrazcAinc, C,H,N',. formed 
by the action of hydrazine hydrate on acrolein. This subetaace has 
the formula 

CH— CH, 

Yh 

Bromine converts it into pyrazolc. A ketonic derivative of f^Taxo- 
line its called pyratoUme, anti has the fnnauia 



CH— CHj 
N COj 

XH 



Bubslitution-productfl of it arc obtained by the interaction of accto- 
acetic ester and phonylhydraEinc: 







CH,— CO 

H,C 



+ 



jyN 



:-C0 • |OC,H, H|yC,H, 



CH,-C=N 

I >N.G,H». 

H^C-CCK 



MfihylplitTiylpiiriuoItme is thus formed. Methylpheiiylbydrazine, 
C,lIs-Nir'NH-('Hs. eondcasL-a similarly with acetoacetic ceter, 
yielding a diinethylplieuylpyrazolone with the fonaula 

CHjC-NCCH,) 

This is anlipjirine, C„TT|,,N,n. which was discovered by Knobr, 
and is extensively employed in nii-dicinc as a febrifuBc. It ciys- 
tallizw in white leaflets melting at 113''; it cannot be distilled 
without undergoing decompnfltioa. It is readily soluble in water 




504 ORGANIC CHEMISTRY. 

and alcohol; the aqueous solution g^ves a red colouration with 
ferric chloride, and a bluish-green one with nitrous acid. 

Antipyrine is manufactured by condensing pheoylhydrazine and 
acetoacetic ester to methylpheDylpyrazoloiie, and subeequeotiy 
introducing a methyl-group into this compound by heating it with 
a mixture of methyl alcohol, methyl iodide, and caustic potash. 

Many other ring-compounds are known, conttuning rings of six, 
as well as of five atoms, but these an beycmd the scope of 
this book. 



CONDENSATIOV-PBODUCTS OF BENZEHE ASS 
HETEROCYCLIC HDCLEI. 

395. Only three of the compounds of this class ■n-ill be described: 
^tno^in^, isoquinoline, nnd indole. The first two are relat-ed to the 
alkaloid^, and the last is important on account of its relation to 
indigo. 

I. QDIHeLIIIE. C.HfN. 

Quinnline is present in c-tial-lar and btine-oil, but it is difficult 
to nbtiiin it pure from tliese sources, Jt is usually prepared by 
Skiuui-'s sjTilhesis, which is describfd below. It is a colourless, 
hiphly refractive liquid uf cliaroeteristic odour; it boils at 236*, 
and lias a specific gravity of 1 ■ U)S1 oi 0°. It has the eharacter of 
a tertiary ha.se, so that it possesses no hydrogen linked to nitrogen. 
It yields sall-s wilh arids; the dichromate, (C,H,N),HjCrjO,, dis- 
»o]ves i,\ith fliffieuHy in water. 

Qiiinoline can be s>T»the.'*ized by various methods which prove 
its constitution. Its synthesis was first effect*'*! by KoNics, by 
passing allylaniline-vapour over red-hot oxide of lead: 



H CH, 

H/^H\CH 



H H 

h/\/\h 



W-*"°- "W" 



+ 2H,0. 



AllrknIIlM 



Skraup's synthesis consists in Iiealinjc together aniline, glyc- 
erol, sulphuric acid, and nilro benzene. In presence of sulphuric 
acid as a dcliydrating-agent, the glycerol lusts water, forming 
acrolein, whieh unites with the aniline to acrolein-anilinc, 
C,Hj-N:CH'CH:CH,. In Koxigs' synthesis the oxidizing-agent 
is the lead oxide; in this it is the nitrobenzene, which ia reduced 
to aniline. Arsenic acid can be substituted for nitrobenzene. 

505 




50 6 



ORGMMC CHEMISTRY. 



Babyer and Drewsen ha^■e discovered another method of sjm-- 
thctiis which proves the constitution of quiiioHine; it cuiuii^ts in tho 
reduction of o-nitrocimiamttldehydp. Tliiw is firet converted into 
an itilt'nnediatc produft, the corresponding amino-coni pound, the 
H-at<)nis of the NH,-groijp of this substaiica being subsequently 
dimioated along with the 0-atom of the aldehyde-group : 



R CH 



H 

H' 




H NiH, I 

O'Am lDDcUniDtiuldehril« 






H H 

s(X)" 

H N 



The last RynthpBis proves quinnline to be an ortAo-subetitutod 
bennene; the cnnstitiilinn <if thj: ring coiitaiTiing the N-atom has 
now to be dctirniincd. This is ofTected by oxidatloa, which pro- 
duces a diba»c add, quinolinic acid, 

H 

hooc/\h 

HOOcL Jh' 



V' 



which on distillation with quicklime yields p>*ridine. From these 
facts it must be conchided that cininoliiie contains a benzene- 
iiueleus and a pyridine-nucleus, witli two or(Ao-C-atom3 commnn 
to both. It may be regarded as naphthalene, in whitJi one of the 
a-CW'HTmtps ktjs hem rrpfncfd by N, It was mentionwl (S63, 
370, ond 387) tliat the assumption of centric bondt w the most 
probable explanation of the structure of benzene, naphtluilciic, and 
pyridine. The analogy between these substances and quinolinc la an 
indication that it, too, possefises centric bondSf so that it has 
the formula 



i<IXI>i. 




ORIENTATION OF Qt^lNOUNE DERiyATlFES. S"? 

The number of isomeric substitution-products is very large. 
The seven hydrogen atoms occupy dissimilar positions relative to 
the nitrogen atom, so that seven monosubstitution-products are 
possible. Twenty-one disubstitution-producta are possible for 
similar substituents, while the number of triderivatives possible is 
much greater, etc. 

396. There are three methods for the orientation of quinoliue 
derivatives. 

First, the relative method (362, 1). 

Second, oxidation. This usually removes the benzene-nucleus, 
leaving the pyridine-nucleus intact, and thus furnishes a means of 
determining which substituents are present in each of these. 

Third, Skraup's synthesis — an important aid to orientation. 
It can be carried out not only with aniline, but with many of its 
substitution-products, such as homologues of aniline, nitranilines, 
aminophenols, and other derivatives. The quinoline compounds 
thus obtained have their substituents in the benzene-nucleus. 
But this synthesis also indicates. the positions of the side-chains 
when an ortAo-substituted or a para-substituted aniline is used; thus, 

/ 
can only yield 






X NH, X N 

OrQia 



and ^(\ only ^QQ^ 

IH, N 

Fara 



X X 

while 1 I can yield 

NH, 
Mtta 

All four possible quinoline derivatives with substituents in the 
benzene-nucleus can, therefore, be prepared by Skraup's synthesis. 




5o8 



ORGANIC CHEMISTRY. 



Tlio nomoriclature of the quiaoliiic derivatives Is indicatetl in 
the scbeine 




Many of the Icnnw'Ti qiiinriline derivalivps arc obtainetl by 
Skhaup's mcthixl, a unmllrr niiinltf'r diret'llj' from qiiiiuiIinR. The 
Rulphonip acids arr Iipsi prppurpd by th* latter metliod. On fusion 
with caustic pnliu^h, tht-y arc mnvcrird into hydrnxyquincilim-s; 
when Iieatt-d witli iwitassium cyanidr, thry yield cyan<H]iiinolincs, 
which oil hydrolysis pivr rarb«ixyhp ucide. 

CariiosUjril is 2-hydroxyqiiinolinc; it ean bo synthesiMd by the 
eliniinatiou of v>'&t4>r front o-aminocinnamic acid: 







IH^COH 

It has a phenoiic character; thus, it dissolves in alkalis, aiid is 
reprecipitated by CX\ 

n. ISOQUmOLIHE. C,[I,N. 
S9T. leoquinUinf is present iu coal-tar, from which HooGBmutrr- 
anri VAN DoBP iHolatM it in the form of it» MpariniJy nolublf 
fii]lphaU>. It is a rnlnuripss Aulistaixrc with an ociour like that of 
qtiiRoline; it iiiHtfl at 2\°, Mtid h«il« at 237°. 

The following tynthetix iiidicjiu?)t Iih constitutinn. On heating, 

CH. CX)OH I 
2' 



18. 



C^.< >NH. 



the ninmomum salt of homophlhalic acid, C«H4<(.qAii 
ooovert«d into fionuiphlhalimide: 

XH COONH, 
C,H,< - 211,0 - NH, - v,^.,v 

NCOOXH. \C0 

tli^Diniliilialimld* 

On treating with phosphonis oxj'cliJorido, each O-ntoin is replaced 
by two Cl-alonis, 2HC1 being aubscqucntly split off, with fonuatioct 
of dichlvroisoqmnoline: 

cHjn 

aioHl 




N. 



Y 

Dl ch I or«lioq«i In nil n e 



ISOQi/INOUNE AND INDOLE. 509 

Reduction with hydriodic acid and phoephoruB converts this sub- 
stance into isoquinoline, which differs from ordinary quinoline in 
that the N-atom of the pyridine-nucleus is not directly linked to 
the benzene-nucleus. 

The products obtained by the oxidation of isoquinoline support 
this view of its constitution. The benzene-ring is removed from 
one part, and the pyridine-ring from the other, so that cincbome- 
ronic acid (*W) and phthalic acid are formed: 




HOOC/\ /^/N /\COOH 

HOOC\/N '•^X/N \/C00h" 

Cfncbonieroiiic odd rhthalic kcid 



Since the constitution of isoquinoline is decided by the synthesis 
described above, it is thus possible to infer from it that of cincho- 
meronic acid, and this method leads to the same conclusion as that 
previously arrived at from other considerations (loc. cU.). 

m. IKBOLE, CgHfN. 

898. The relation between indigo and indole, mentioned at the 
beginning of 896, is made evident by the following series of trans- 
formations, most of which were discovered by Baeyer. 

On treatment with nitric acid, indigo, C,bH,oN,02, yields an 
oxidation-product, isalin, CgHjNOj, which can also be synthesized 
by treating o-nitrobenzoyl chloride with silver cyanide; on hydrol- 
ysis, the resulting nitrile yields o-nitrobenzoylfonnic acid : 



C»H,<jTQ?j,j2-*C^«<CQ?Qj^-^CoH^< 



NO, 



COCOOH. 

robenxo 
chlorjdo C7MiId« formic acid 



D-Nltrobeniojl o-Nitrobenxo?! o-Nitrobenxoyl- 

• ■ .|d 



On reduction, the nitro-group in this acid is converted into an 
amido-group, water being split off simultaneously, and isatin 
formed. It has therefore the constitution indicated by the 
equation 

o-AmtiiobeQMirirormic add !■■([□ 

On reduction with zinc-dust and hydrochloric acid, isatin takes up 
two hydrogen atoms, forming dioxindole, CaH^NOj. This com- 



5IO 



ORGANIC CHEMISTRY. 



pwind also results by tlie elinuiuition of wstpr rrom the unstable 
o-aminomandelic acid, which dcUrrmiiies its constilutioD : 



Nil H /NH 

»-lKilBoa*D4»li« mU I 

OH 

Ijioxlndotn 

On reduction with tin and hydrochloric acid, dioxiodolc yialAx 
inindatt, CgHiNO, which is also obtainoil by rc^uctioo of (MUlro- 
phciiylaoulic acid aud suUswiuc-iit cliniiiiation of water: 



C,H.< 



NHIH 






'ndtit. 



wn tlislillfd with zinr-dust, oxindole is convert-ed into ii 
C,H,X, which must, thcrcforp, have the sinicture C,H,<^*^H; 
or, written in another way, 




NH 



/( therefnrf poiarsitfa a bmsmf-ttuetvu$ condenatd mth a pj/mU' 
nufi^^s. Il d»e!<, iQ fai-l. (li»|ilay sumc of the propertirs character- 
istic of pyrrnlr; ihus, it U a very wvak base, anil giv<9 a red colour- 

atkni with hvdrt>chlnric acitl. 

NH 

fi-MfihifiindaU, or ikatole, C,H,^ ^f-'H* •* prweot in tee«. 

Tt b abo found in a spccini of wood grown bo India, aod if 
formed in th« putrefactive decay of albutoio, or by fusing albomio 
with caustie potash. Skatole is characterised by it< dintgreeable 
odour. 

luljfo. 
The constitution of indieo is inferred from its formation from 
itaiia dUoridc, obt^oed by the interaction of isatin and phosphorus 



I 



INDIGO. 



s»» 



pentachlorido: on rPclucUoQ with zinc-dust and acetic add, it is 
tnuisformed into indigo: 



N 



cjB.<(^>cci + ac<^>c»H, 



+ HH H 



N 



H 



= CJS,<^>C=C< ^>CJI, + 2Ha 

Sinceon treatment with siilphurio aeii!, and subsoquent reduc- 



tion, o-dinitradi-pkitiyUiiactiylene, 



C.H,CsC~CsCC.H, 



13 COC- 



NO, NO, ' 

verted into indigf'. the two isfttiti-residues in the latter must be 
united by a rarbon bond. 

399. Indigo ha« long liceu known as one of the finest blue dyes, 
and is very permaiifnt, (H-ing unafT(>ctt*d by light, aridx, alkalis, 
or nasliing. It is prepared Jrtmi certain plaata, among them /nrfi- 
po/tTrt t\nctaria and Ivploshfcka. These ore eultivatrd on a large 
scale in iit-ngal in Intha — whence the dye deri\e» ita name — as well 
as in Central Americn, Java, and other countries. IndJgo is not 
present in the plant an siieh, but in combination at the f^lucoside 
indirnn, which is chiefly in the Inaves, and ean be extracted with 
hot water. It is crystalline, and has the formula C„1I,,N0, + 3H,0. 
In additinn to the Klucoaiile, the leaves contain an enzyme, whose 
activity, like that of all enzymes, i« destroyed by hntlivg water; 
hence, when indienn itseU is to be preparc<i, hot water must be 
employed in the cxlraclion. With cold water, both indican and 
the unchanged enzyme dissolve, and the glucoeidc splits up into 
glucose and indoxyl, C,HjXt>. or 

NH 



C,H,< 



C(OH) 



>CH, 



a Hiibslaiicc wliieh \a moderately stable in acid solution, but in Hilute 
alkaline solution is quickly oxidized to indigo by atmottpheric 
oxyKCn. 

The manufacture of indigo from the plants containing it is 
carried out by the method indicated. The leaves of the indigo- 
plant are allowed to remain immersed in lukewann wat^r fnr some 
hours; the aqueuu:! extract is "eburned" by a revolving water- 
wheel with woaien paddles, which aerates it, and thus oxidizes the 
indoxyl to indigo. The oxidatioti-prncess is farilitated by the 
addition of slaked lime to make the liquid faintly alkaline. The 



5" 



ORGANIC CHEMISTRY. 



indigo formed sinks to tlio bottom, ie rcmovetl by filtrBtion, and 
dried. U is put on tlie niarkui in tKc fimu of Bmall cubes. 

In addition (o the blue dye, iniiigoiin, romintTcia] indigo con- 
tains inJiff>Kiuten, iinliKf>-lm>wn, and intiiKo-rwI; these ran be 
oxtraclcfl by watrr, alroluil, and ulkalin, in whirh indiKotin \s insol- 
ublf. The tattrr '\3 u dttrk-bluu pwwdi-r, which, wlica rublmd, has 
ft copp^r-likc tustrc. It can be sublimed in vacuo, so that it is 
possible to dctprniinp its vnpmir density. It is insoluble in most 
solvents, but can be prj'stalliied from nilrobeiizonc or aniline, U., 
dissolves in filming gulphuric acid, with formation of ailph 
acids. 

On account af the great indii^txial importance of indign, maaj 
fttlcmpls have been made to synthesize it. One of these is commer- 
cinlly pviooessful, (■nahtin;; the artifirial priMhict. to be sold at the 
enme price as natural indigo. It yieldi^ pure indigotin, whirh m aa . 
advanlagc in some cases. 

Tliis melhiid is employed by the B.ADisriiE Axiux- vfiit Soda- 
pAuatK of I.udwigehafen-nn-Rhiiie. Aittliranilic acid, or o-nniiiit>- 

benxoiio acid (351), ^•H«<^,(j(^'j^. rombines with monochloroacetic 

»cid to form phciiylglycocoll-<^corboxylic acid : 



^•"•^COOH 



NH|H + ClIiI^COjH 



_. r H ^NH H^C- CO,[H 

^ '"^^ClO |0H """ ' 

rbeiirl4tIro»oall-oacarbciK;ltc b«Ii1 



Oq f^ion with eatiMic soda, this compound is trauafonaod inUi 
indoxyl, C,n4<p.,.i,. :^CH, which in alkaline solution is con* 

verled by ntmo.'ipheric oxidation into indipo. 

The manufacture of indigo by this method has been rend- 
ered possible by the discovery of a satisfactory manufacturing- 
jiroeess for anthranilir arid. This substance isnbtained by oxidizing 
naphthalene to phthalic acid <326), which can \x converted into 
anthrunilio acid, with intermediate production of phthaliniide 
(351). 

On reduction, indigo takes up two hydn>gen atoms, with for- 
mation of indigo-whUe, C^HiiXjO,, a wliite, crystalline substance, 
whose phenolic character ia pnn-ed by ils solubility in alkalis. la 
alkaline eolutioo it is speedily reconverted into iudigo by atmoa- 



DYEING IVITH INDIGO. 513 

pheric oxidation, a reaction employed in dyeing with this substance. 
The dye is first reduced to indigo-white, and the fabric thoroughly 
soaked in an alkaline solution of this compound; on exposure to 
the air, the indigo-blue formed is fixed on the fibres. This process 
is technically known as " indigo- vatting." 

The reduction of indigo to indigo-white is variously carried out 
in the dyeing-industry according to whether wool, silk, or cotton 
is to be dyed. Reduction is best effected with a salt of hyposul- 
phurous acid, HjSjO^ ("Inorganic Chemistry," 83), for the two 
fcst named. The solution is mixed with zinc hyposulphite, and 
treated with excess of milk of lime, which precipitates zinc hydrox- 
ide. The indigo is mixed with water, and warmed to about 60° 
■with this solution of calcium hyposulphite, a concentrated alkaline 
solution of indigo-white being obtained in a short time. On 
■adding sufficient water to this in the dyeing-vat, the bath is ready 
for use. 

The hyposulphite reduction-proc^s possesses the advantage 
that the reduction stops at indigo-white, so that almost none of the 
indigo is lost 



■i 



ALKALOIDS. 

400. Plants of wrtain ffliii5[ies contain substances, usually of 
complex I'oinpcwitioii and basic charac-icr, callKcl alkaioifis. Thoir 
classificatioa in one gtxjup in of uld Htaiicling, ami had its origin in 
an itlca aiinilar to tlial which prr-vaiW conctrning the vegt'lablo 
acid?; (1) prior tn Uic iJctcTtiiinatKm of thpir ronstitu tion. JuHt as 
the latter have bran subdiviiler^ into diftercnt classes, such as 
monobasic, polybasic. aliphatic, and aromatic acids, so it has bt-wmic 
apparent that the individiml alknlouint can bo nrranf;c<l in very 
difT^nnt elafuM-!!. MoKt or the iilkaloiils arc, hon-evcr, related to 
pyritiine, qiiinotino, or isnqiiinoliiip, while a smaller number Ik-Ioe 
to the aliplmtir series. Some of the latter class were described^ 
along with the compounds of similar chemical character, aniuo^ 
them are betairu- (200), nntscarine (232), choline (162). caflcine anc 
Ibeobromine (248). (.tnly alkainiils which are dcrivalivfj* of pyrid-1 
ine will be desrriboil here; to these the name alkaloids, in its 
mote restrietcd sense, is applied, the other substances bein^ known 
u VGigetabte bases. 

401. It is seldom that an alkaloid \» pres*nt in more than one 
family of plants; many oE these do not contain them. Almost alt 
alkaloids are pre»ipnt in dicotyledonous planta. Only a few, sueK 
as coniine and nicotine, are litjuids; most of them arc erj-stalline. 
Many are optically actU'e and la-'vo-rotatory, it being very excep- 
tional for them to exhibit dextro-rotation. They hove an alkaline 
n-artion and a bitter taste; most of them aiv initolnblc in water, 
more or less soluble in ether, and readily soluble in alcohol. Most 
are inaoliiblo in alkalis, but dissolve in acids, forming salts which 
are sometimes well-defined, crj-stalline substances. 



PROPERTIES OF THE ALKALOIDS. 



5»5 



OtJDEBANB obBcrvi>d tliiit tlip gpecific rotatOTj- power (ST, S) of 
the alkaloid t-alUi of atrouR aeide m nqueoufl solution depends only 
on lh« allcalnid, aiid is not iiiHutricpd by the nature of iho acid- 
radidc; while for Ibt.* salts of vrcak acids it depends on the nature 
of botli the alkaloid find tlic ftcid. This ia accounted for by the 
theoiy of electrolytic diseociation : vlien dissolved, the Ralta of 
strong acids are almoEt coniplcttfly lomini^d, so that in solutions of 
equiinolecular concentration tliero is always the ««ni» amount of the 
optically anive cation present ; the salts of weakscidii, however, are 
to a great extent nan-ioni2ed, 60 that they possess u different 
(oDulIiT) Bpecilic rotatory power. 

Many allcaloicis can W ideiitified by eharaetcristiR colour-rcao- 
tjons. Some substances prpcipitatc many of tlie alkaloids from 
tlieir B(|Ucous or acid solution; siich gcntral nlktiloid-rfaiicnis are 
ttiiiiiia (345), phoephnmnlyhtlic acid, mercuric potaseium iodide, 
KI-Hgl, ("Inorganic Chcmistn,'." 148 and 873), and othere. 
Some alkaloids aro cxeeefuvely pwisrmoua 

Strong t*a is sometime* employed as an antidote, the tunnio 
present precipitating the alkaloid, and rendering it innocuous. 

Most of the alkaloids air- tertiar>' amines, so that they yield arldi- 
lion-piTMhicts with methyl iodide; none of them possesses the 
character of a primarj- amine. Many contain acid- residues or 
methoxj'l-grmips; the fonner are split off by saponifieation, effected 
by healinp with bascB or aeida, the latter by heating with hydriodic 
add, which yieldH methyl iodide. Hydrnxyl-gronps ean bo ttnteii 
for in the onlinary way with acid chlorides or acetic anhydride (98 
and 96). On ilry dislillatitm, or nn heating with zinodust, sub- 
stituted pyridines an? eonictimrs formed. 

On account of the complex constitution of tlic alkaloids, the 
structures of ninny of them have not hitherto been determined, 
80 that a rational elaswiicatioii is not yet [jossible. 

402. In the exirariion of the alkahkU Irani planla the latter are 
cut Up into fine pieces and lixi\iate(l witli acidified water in a 
conical vat tapering towards the bottom, where there i.s a layer 
of flome material such as glaea-wotd or lint. The cfTeet of this 
is that the acidified water pradually sinks through a (hick layer of 
the substance under extraction, n process technically knowu aa 
"percohition." Dyes, earbohydratcs, inoncianic ealta, etc., are 
dissolved out along with the alkaloids. When the alkaloid ts vols- 



5'6 



ORGANIC CHEMISTRY. 



tile ^ith st«&m, it can be separated by this means from the liquid, 
after making tlic noixture alkaline; when it is comparatively inaol- 
ublp, it fan be obtaJnpd by filtration. Furthfr purification te 
always ncfr^sxary, Hiid it; cfTected by cryetallizuig the free alkaloid 
or one of iu salts several times. 



IHDlVlDUat ALKALOnM. 

CoDJine, C.H,.N. 

403. The synthcsiK of coniine is described in 388, It is present 
in spotted henilook (Conium maculatum), and is a colourless liquid 
of stupefying odour. It boils at 167°, is but slightly soluble in 
water, and is veiy poisonous. 

Hiootina, C,oH„N,. 

404. Nicotine in present in cnml»n«tlnn with malic and citric 
aeitJs in the Iravrs of thr lobacco-plant {Nicotiann tabacum). It is 
a coloiirlrss, oily liquid, whirh is la^vo-rotat-nry , and readily soluble in 
wat-cr. It has a tobacco-iikr odour, which is not nearly so marked 
in a freshly-distilled sample m in one which has stood for eoine 
time. It boiU at 246"*', and is excessively poisonous. It quickly 
turns brown on exposure to air. It is a ditertiary l>ase; on oxt^lalion 
with potassium permanganate, it is converted into nicotinic ackl 
(389) , proving it to be a ^-dfrivalive of pyridine. It is assumed to 
contain a pyridine-nuclous. and a hytlrogenatcd pynole-nucleua 
whoee N-atom is in union with a methyl-ftroup. 

Atropine, C„H„NO,. 

105. Atropine is present iti tlie berry of the deatlly nightshade 
{AtrojM beUadontia) an<l ill tlie thorn-apple, the fniit of Datura 
stramonium. It is erj-stalllne, mplt.i at llo-.')'', and is very poison- 
ous, il exercises a "mydriatic" action — that is, when dropjjed 
in dilute solution on the eye, it expaiiila the pupil; for this n^asou 
it is employed in ophthalmic surgery. It is optically inactive. 
On heating with hydrochloric acid or caustic soda to 120°, it takes 
up water and splits up into^'optnc and tropic acid : 

C.,H„NO, + H,0 = C,H„NO -t- C;H,„0,. 

Jktro(>lii« Ttoplae Tfopt« add 

It can be regenerated from these two substances by the action 
of hydrochloric acid. Atropine is, therefore, the tropine ester 
of tropic add, which is a-phenyl-^hydn>xypropionic acid. 



HYOSCYAMINE, COCAINE, AND MORPHINE. S'T 

CbH,-CH<«5?jtt ■ The constitution of tropine is probablya 
carbon ring of seven atoms with a "nitrogen-bridge," 

H,C— CH— <;H, 
N-CH,CHOH. 

H,c— CH — in. 

This formula explains the formation of various substitution-pro- 
ducts, derivatives of tetrahydropyrrole* or pyrrolidine (ring I), of 
piperidine (ring II), and of heptamethylene (external carbon-ring). 

Hyoicyamine, C„Hj,NOj. 

406. Hyoscyamine is isomeric with atropine, into which it is 
■converted by the action of alcoholic potash; it can also be split up 
into tropine and tropic acid. The isomerism is probably stereo- 
chemical. 

Cocaine, CHaNO^. 

407. On account of its use as a local amesthetic, cocaine is the 
best known of the alkaloids present in coca-leaves {Erytkroxylon 
coca). It is crj'stalline, is readily soluble in alcohol, and melts at 9S°. 
On heating with strong acids, a benzoyl-group and a methyl-group 
are split off, with formation of ccgonine, CjHjjNOj, so that the 
formula of cocaine may be written C,H„NO,(OCH,)(COCoH(): by 
benzoylating and methylating ecgonine, cocaine is regenerated. 
Ecgonine is a carbonyl-derivative of tropine. 

Morphine, C,jH„NOs. 

408. Morphine is the longest-known alkaloid; it was obtained 
from opium in 1806 by Serturner. Opium is the dried juice of 
the seed-capsules of Pnpaver somniferum, a variety of poppy. It 
is a very complicated mbcturc, containing caoutchouc, fats, resins, 
gum, sugar- varieties, albumia^, mineral salts, meconic acid, some 
more organic acids, and other substances, together with numerous 
alkaloids. Twenty of the last-named have been identified; of these 
morphine is present in largest proportion, and constitutes about 10 
per cent, of opium. 

Morphine is crystalline, and melts with decomposition at 230°; 

* Of. (ootnot*. p. 4TO. 



5i8 



ORGANIC CHEMISTRY. 



it is slightly soluble in wat^?r, without, odour, nnd is pmpioyed as an 
aiindv'Tie rimI narcolic. On distillation with zinc-dust, it yiclils 
pymjie, pyridine, qumolinc nnil pliensnthrene. It is a torliiry 
base, an<l also possesses a phenolic character, since it is soluble in 
alkalis. 

Narootine. CjjHj^'O,. 

409. NareoHne is )>rosent io opium to the extent of about 6 per 
cent.. it« percenlas'^ bfiiij; next to that of inorpliinc. Il is cn,-stalline, 
melts at 178*, and is slightly poisonous. It \» a weak, tertiary 
banc, it» salts readily undergoing h>*droIylic decomiKwilioti. It 
contains llirre mctlioxyl-jKroiips, so that its fornnila can be mitten 
C,4I„N'0,(OCH,)3. jVormxwCnc lins the fomnila C„II„NO,(OII),. 
On hydmlysis, nnrcolJnp yields the anhydride of moconinic acid, 
or mrrrmin, C,„H,oO,, and fotaminr, Ci,I],,NOg, which is a di-riva- 
tive of isoquinoline. HroniiDe coDverts narcotine into dibromo- 
pyridine. 

doinine, C'jjH^NjOi. 



410. The bark of certain trees of the Cinthona and Rem 
families contains a prtat number of nlkaloiibt; of these twcnty-four 
have been i-fnlated, hut it is pmbuble that more am present. The 
most important of th^-m is quimnc, nn ari'nnnt. of its antt-febrile 
(ffeet Citiffioninr. C„HjjN,0,. is the next hpst-knnwn; its phjTsio- 
lugienl prtion is similar to that of qninine. but less pronounced. 

Ilk addition to alkaloids, these barks cont^n Tarious acids, sucli 
Ad (luinic, quinovic, and qiiinotannic acids; indiffeTcnt subetances, 
such as iniiiKivin, quina-red. etc.. are al«) pxeeeat. 

Quinine is wry slijihliy soluble in water, and a, lievo-rotatory; 
in the anhydrou.* stale it luelts at 177*, and at .57° when il con- 
tains thnr nKileculfsof waterof crystalhr-ation. UisualronEbusc. 
and both N-atoms are tertiftry. It unites willi tvro equivalents 
of an acid. In dilutir solutiun the salts of quinine c.'diibil & splendid 
blue fluorescence, which serves as a test for the base. 

The eonatitution of quinine has been partially elucidated, chiefly 
througb the researches of Kon«;s. It seems to contain two ring- 
systems, and to possess a hyclro.xyl-group and a mcthoxyl-group, 
8o that its formula may be written 

CH,0-C4I,N-C„H,»(0H)X. 



J 



STRYCHNINE. 



5'9 



^"ecordantc with the nomenclature in 396, the first of these riiig- 
Q'stems is G-niethuxytiuiruilitip, a wtnp<nin<l which is obtained 
by fudng (|uiiiiiie \vith catintie [Kitash. The second ring is prob- 
ably similar to the one assiitned to be present in tropiue (406). 

Strychnine, C,tHjjN,Or 

411. Three extremely poisonous ulkuluuU, 6try<Jinine, hrucim, 
and curarinf, arc present in the seeds of Slryciinns nw-J I'^micu, as 
well at in others of the Strychnos fnmiU'. lattle is known of the 
chemical nature of curarine. although it has been much studied 
from s physiological stan(l|)oint ; whrn atlm inist<>reiJ in sniail doses, 
it produces total paralysis. Strychnine and bnicine cause death, 
preceded by tetanic spaama — that is, contraction of the muscles; 
ourarino is, therefore, employed an an antidote. 

Stryehnine id crystalline, and tnclta at 265° ; it is altuost icuKiluble 
in water. It ia a monoliydrie, tertiary baae, only oni> of its N-atonia 
exliibituig basic propertiL<£. On futiiuii with caustic potash, it 
yields quinoline and indole; and when distilletl with slaked lime, it ia 
converted into ;3-ptcoline (38&). Heating with slnc-dust produces 
c&rbftzolo(379>au(lother6ubstAace8. 



AIBTJUms. 

418. This section contains a short account of the albumins, 
which are compounds of great importance in the animal ami vege- 
table kingdoms, but of such complicated stnicture that their chem- 
ical investigation is a matter of extremr difficulty. Their great 
phvfiologieal importance is made apparent by the fact that the dry 
material in animal bodies— apart from the mineral constituents and 
fat« — (ron^sls almost wlioUy of albumins, by tht-ir being an esKenttal 
consiliiupiit of each living plaiit-eell, and by their forming the most 
important part of liuman and animal food. An aiiinml can exist 
without i&ls and carbohydra.l'eA for a protracttnl iK'riod, btit its 
death is assured by the withdrawal of albuniins from its nourish- 
ment. 

The investigation of the albumins i.'J rendered difReult not onlv 
by their complicated Ktnirture, hut a\t^ by the fact that, with few 
exceptions, they do not crj-stallize, and cannot be di.stilled without 
undergoing dccnnipnsition, so that advant,age cannot be taken of 
t<h«K valuable luib in the itiolation uf individual eubstances. More- 
over, many of the albumins ehanRo very readily into other sub- 
stances, and the distinctions between the different varieties ftro 
sometimes by no means marked. 

The aibiimins, proUids, and olhuminoids are closely relatwl, and 
Are cloaseil together imdcr the name proteins. The true, or native 
allmiiiins will be first considcrctl. Since they aometiinea exhibit 
great differences in physical an<l chemical behaviour, it is nece^acy 
to first state the general properties charaetoristic of the albumins. 

They contain only five elempntfi, and do not fliPfer much from OMJi 
another in comjKtKitJon. an the following table shows : 

Carbon 50-55 per cent. 

Hydrogen 6- 5-7 -3 „ 

Nitrogen 15-17-6 ,. 

Oxygen 19-24 „ 

Sulphur 0-3-2-4 „ 

Those of one variety, called nueieins, also contain phospVio 



ALBUMWS. 



5»« 



r 



Both nitrogen and sulphur arc linked in the albumin molecule in 
more ways than one. A portion of the nitrogen is readily eliminated 
in the form of ammonia by treatment with a hot, dilute solution 
f caustic potasli. although the greater part is not removed by this 
means. On warming the albumins with caustic potash, a portion 
of the sulphur is similarly spht off in the form of potawium sul- 
phide, which can be recognized by the formation of a black precip- 
,il«le of lead sulphide on addition of lead acetate; ihc remainder of 
sulphur can only bo tletected by completely breaking up the 
te, which isetTecte<l by fusion with caustic potash and potas- 
sium nitrate. It frtllnn's that the albumin molecule must contain at 
least two atoms of mlphur. 

Up to the present it has not; been poR=dblc to give an empirical 
formula for albumin: attempts to detcniiino the molecular weight 
by the eryoscopic method (14) lead to tiie conclusion that tt must b* 
verj' great, the number obljiined being about 15,000. 

413. The 8olu(4<uis^of the albumins are all optically active and 
Iffvo-rotatory, 

The albnminK are collwida ("InorRanie (lhejnLsir>-," 186) — that 
i«, do not diffuse thrfiugh parchment-paper. Advantage is often 
taken of this in sepfirating them fmiii rbU.'!! and other crystalloids 
(foe. ct'r). Very few have been ohtainerl crystalline, among them 
serum-albumin; most of them are white, amorphous powdvrs 
with no definite melling-pf>int.s. (Jn heating, they carbonize, with 
evolution of gOBes. 

Some albumins can he " salted out '' from their solutions, others 
-Muinot. This is an important aid in identifying and separating the 
different varieties ; usually eumoiun »ialt or magnesium sulphate is 
empIovL'd. It is n^markable that not only all albumins, but pro- 
teins in gL-neral ran be coniplcicly "salted out" from llu-ir k»1u- 
in both neutral and acid liquids by saturation with ammonium 
phate. The naltvo albumuis can be fractionally precijjitated 
aqueous solutions by gradually increasing the eoneentration of 
c ammonium -sulphate solution. The point of concentration at 
'hieh a salt begins to precipitate an albumin i.s just a.s charac- 
ristic for the latter as, for example, the solubility is for a 
crystalline substance. ftTien the '* salting-out 'I is effected at 
ordinary temperatures, it causes no change in the properties of 
the allnmiins; their solubilities are the same after as before the 
operation. 



tJous 




i" 



ORGANIC CHEMISTRY. 



Addition of alcohol precipitates the atbuminB UDchim|;:ed rroro 

• an aqueous solution; strong alcohol cc<t^uiai<a them, as tiao does 

IbeBtiug with water. Fur each native albumin there i;: a definite 

looagiilatioii-poiiit; in other words, tacli alhumin cnaftnlatni: at a 

definite temperature. On coagulation, the differences in Ntlnbilitr 

between the albuniniK viuilsh; they arc all rendered insoluble in 

neutral wolventK, and can Ik- hroughl into snliition apun only by 

treatment with dilute caustic alkalis or with mineral acids. A solu-^ 

tion, which behaves exactly like those thus obtained, c&a be pr^* 

pored by boUiofr uneoBgulaled albumins nith a large cxoam of 

acetic acid or with caustic alkali. 

In this process the native and coajzidated albumins undergo a 
Ichanp'. which is calle<l dmaiuralion. When this is effected with 
Lalkali, the product is termed an aJbumiTuUe ; when an arid is eni- 
ploywl, a eyntonin or and albumin. Botli these eubstanccs differ 
in composition from the ordinary albumins; since, as mentioned in 
413, when thuR treiitrd. they oplit off nmnionia and sulphuretted 
hydrogen. The albuminate nnd .vyntonin are quite insoluble in water, 
and arc, therefore, precipitated by neutralizing their solutions. 

414. DfcimijwjfitioTt' products. — I*rn!(»nped Ixiiling with dilute al- 
kalis or mineral arid» dcconipoHcs the albumins, water being taken 
up.and ammonia, sulphuretted hydrogen, and a series of amino-acids 
formed. Sinee these eonstituu- ihc decoriiposilion-produeta of sU 
albumins, it follows that the latt^-r only differ from one another in 
the proportions in which the.sc are present. These amino-acids are 
tyuaim (347)— which proves that the albumin molecule conioina, 
benzene-nuclei — latcine, aspartic add, amino^utaru: or gliUeuninic 
0<n'rf(200); diamino-acids, ftueh as amilhinf (200), itrffinine {2M) 
id others, are also obtained; of all Ihese leucine is formed in 
^greatestaniovint. Tlie same amino-acids a.Tv produced by (he actiun 
of the ferment tri/psin, which is pawiit in the pancreatic gland: 
decompoation due lo putrefactive decay produces onimatic com- 
pounds, such as inddc, skataU, phenylacelie and, fKnuA, cthoI,' 
and 60 on, in larger proportion. It is probable that the nitro* 
genous substances arc the primary decomposition-products ; while 
such substances as earbonic arid, acetic acid, and its bomo- 
loguta up to caproi'c acid, formed by an oxidizing action, or by the 
^action of caustic alkalis or of acids, on the albumins, are probably 
iuoed by the subsequent decomposition of the amino-aeids. 



ALBUMINS. 



5*3 



The albumins are precipitated from solution by various sub- 
stances, either by coagulation or by the formation of comjiounds 
in«ihible in water. Coagulation is effectecl by the addition of min- 
eral acids, preferably nitrii: acid, since an exotrss of hydnwhloric and 
[Other acids rediseolves the albumin, with fonnatioo of a ayntooin; 
this (loes not take placo with nitric acid. 

The fonnalion of cnmpnimds insoluble in wat*>r results on addi- 

, lion of salt« of most of the heai'y metals, especially copper suljtliale, 

kferric rhloride, and an acidified solution of mercuric chloride. Tlie 

Sumiiis, therefore, brhave like weak adds, which with the o\iili» 

f^bflBemetalsyieldcompoulld9o^ the nature of salts. Tfaia acidic 

iture Is indicated by the fact that neutral solutions of aJbuiuin 

[partly disfe-olve freshly-precipitated ferric hydroxide. The fomm- 

' tioa of eo()f)er a1btm)inali>£ furnishes a gooil tnethnd of obtaining 

lumins free from lumeral coiistituent.s. which are alwa^*)! present 

I A greater or less extent ; on addition of an iui<l to these copper 

cnmpouud.-4, the ulbumlti ja set free af;ain in the dcnat urrrl state. 

Some weak atids yield insoluble compounds with albumin, which, 
therefore. Iwhavr-s also like a ho^c; in this respect it exhibits com- 
I>Ie1e aralogj' t-f) it.s main decompositifin-products, the amuio-arJds. 
Among these weak aeids are tannic arid, pin-ic acid, jthospliotun'isU'r 
ccid, and others. The albumins are completely precipitated fruui 
solution by phoephotungstic acid, a metho<l employed, along with 
of coagulation by boiling, and precipitation with alcohol, ui 
rate liquids from the albumin dissolved in them. The acitUc 
and baaic properties of the albmnino recall thtMo of tho poeudo-acida 
(381) and (Jseudii-haitPB (S80); tluiK, in the frw state they have a 
neutral reaction towards uidiealnre, but the reaction remains neu- 
trvl when stronu iicida and Iwu-m-s arc added (281). 

415. Various Icstx jar olbumiTUs arc known, among which the 
following may be mentioned. 

1. MiUon's n-a^ent, which is a solution of mercuric nitrate con- 
laining nilroui^ acid, yields a red, coagulated mas» on boiling. 

2. Tito rnntfimpwtrin-rfueU'nn, which consists in the foraiatitm 
of a yellow colouration on treatment with warm nitric acid. 

3. The biuni-rcmiion, which depends upon the formation of a 
fine violet^re<l colouration when caustic potash is added to all>u- 
Biin, and Ihen a dilute {2 per cent.) solution of copper sulphate 
drop by dmp. Thia reaction derives its name from the fact that 
biuret, rm ffluiilar treatment, gives this colouration (2&3). 




S»4 



ORGANIC CHEMISTRY. 



The albumins can be classified into the following proups, 

1. Native or true albumins, which arc srubilincied into four 
groups. 

(q) The albumins, including »eruin-albuniin, egg-«lbumln, milk- 
albumin, miiscloslbuniin. 

(6) GlobuliiM, inctiiiling serum-globulin and vegetable-globuUii. 

(c) Coagulablc aUAtmvm, including fibrinogen, myofdo, and ^u- 
ten-protekiis. 

trf) XueUa-atbumina, in(?tu(ling casein and vitcUin. 

3. Becompositlon-prodDctB of the trne albnmlni. 

(a) Dtnatunil atbumiits, including acid albumins (ayntonins) 
and albuminates. 

{b) AlbumoKB and peplorus. 

3. Proteids, compounds of albumin with other, usually very 
complicated, eubstanccs. 

(a) Nitdea-proU'ids, compounds with nucleHo add. 

(fc) HirmoglobiTW. 

(r) Gtueo-proitids. compounds with carbuhydrates (mucins). 

4. Albuminoidi. 
Some particulars may be g^vcQ roganling the various claasn' 

namvd. 

The aibumins arc thp host known and most readily obtained of 
the albuminous boilirs; all of them form welUleRned cr>-slai8, 
and are therefore among the few substances of the class which are 
known to be individual chemical compounds. Th^ fUsmh-e in 
water, and tn dilute acids, nlkali», and .snlt:-f^olutiaiis. 

Their neutral erilutione cannot be salted out with nodium chloride, 
magnc^um sulphate, or a scml-saturatcd solution of ammonium 
sulphate — a method of separating them from the globulins, which 
always occurs along with them. 

The globtiiins arc further distinguished from the albumimt by 
being insoluble in water, although they dissolve in dilute, neu- 
tral salt-soluttune, and in solutions of aUtali-carbonates. At 30" 
they can be completely salted out by magnesium sulphate, and partly 
bj' wdium chloride. They have not been obtainc^d crystalline. 

Coagulahip albumins have the property of assuming the glaronus 
state, intermediate between solution and ctiagulatlon. In this con- 
dition they arc itiNtlublc in water and salt-aolutions, but ran be 
made to coagulate uiitlcr llic influcuet: of heat, strong aloobol, etc- 



ALBUMINS. 



5«S 



1 

I 






■ 



The nxicUo-albumim contain phoephoms, and for this reason 
formeriy classed ■with the nucleo-proteids (416). Thoy are 
iWpty (iistinguiBhed froni them, however, by yieliling xanthine 
baseH flinuiig their dectiinpuidtitm-product*. The iiucleti-albuniins 
have H dUliiictly acidic character; all (if iherii turn bhie litmius red, 
and in tlic free atato art cmly eliKhtly soluble in water, though readily 
«ohibl« in Uic form nf thrir alkuU-Kalt^ or aiiinu}n)uiii saltis. The 
aolulions of their salts do not coagulate, and can be boiled without 
undergoing any change. 

Dcnaturtd albumin was referred to in 413. 

Albumosts and pcpfones can be obtained from all prot«Ins by 
'suitable hydrolyss. They have the albumin rharnrler. boing insol- 
uble in alcohol, and an-swering to the xanthnprntein-tcjit and biuret- 
test (415, 2 and S). They rn^iilt from the notion of gastric juice 
on proteins, Tlicy an- to Ik- looked upon as intf rnicdiatc products 
in the hydrolysis of albumins, the albimioecs being nearer tlie pro- 
tcina. and the pcploiies nearer the aniiiio-acids. 

The albunioscfi arc the soluble decoiupusiiiun-produets of albu- 
m : they cannot be coagulated, but can bo salted out by Kahs such 

aiiununium sulphate. 

The peptones arc the final, raniptesl decomposilion-produeta of 
the iifttiv* albumins; their colour-reactions (especially the biurct- 
reaction), their contttitiition, and their physiolngieal behaviour 
indicate that thoy should bb Hassed with the albumins, but they 
caunot undergo further dceomposiUon without being eonvertcd into 
substances of wholly different character, the aniino-acids. 

416. Nearly related to the true albumins are the proieids, com- 
pounds of albumin with other subslancee, usually of a very com- 
plex nature. Like the true albumina, they are insoluble in alcohol, 
by which most of them are eoagulaltnl. 

Xueieo-proUids derive their name from the fact that they are 
the prineipal consUtueni t>f the cell-nuclei. Tliey are compounds 
of albumins with nitdcins — that is, compotmds of albumin with 
phosphoric acid or a nucleic acid. A nucleic acid ia piKisphoric acid 
which is partially saturated by uuion with basic substaiifcs, such 
as hj-poxan thine, guanine, xanthine, etc., and is to be looked upon 
as an amide. The composition of the nucleTns differs eonsiderably 
from that of the inie albumins; Iheyeonlnin about 41 per cent, of 
on, 31 per cent, of oxygen, and 57 percent, of phosphorus. 




5>6 



ORGMHIC CHEMISTRY. 



The nucleTns have a markeflly acidic character; thoy are insol* 
able ID water and dilute acidi:, bul snluble in caustic alkalis. Tbey 
answer to the same coUiur-tPsts as the albumins. 

There is not much djffereni^ in c mnpfisition between the nucleo- 
proteiidB and the tnic albuniuis. this b