摘要:

J O U R N A L THE CHEMICAL SOCIETY. H. E. AIMSTRONG, Ph.D., F.R.S. HORACIC 1'. BROWS, LL.D., F.R.S. J. DEWAR, LLD., F.R.S. l\rYSDHAM R. DI-Ns*r,is: M.A., F.R.S. H. J. €I. FENTON, M.A., F.R.S. c. E. GltOYES, l".ILS. R. Bf iu,nor,L\, F. R. S. H. FORSTER MORLEY, M.A., D.Sc. A. Scow, D.Sc., F.R.S. W. A. TImm, D.Sc., F.R.S. 'r. R. THOKPE, LL.D., V.R.S. &bitor : W. P. WYNNE, D.Sc., F.R.S. 1900 VOl. LXXVII. L O N D O N : GURNEY & JACKSON, 1, PATERNOSTER ROW. 1900.RICHARD CLAY & SONS, LIMITED, LOI~DOX & HUNGAY.J 0 U R N A L OF THE CHEMICAL SOCIETY, TRANSACTIONS. 6onunittec of $!itblication : H. E. AIm:,iiiuNC, 1’11. L)., F.R.S. HORACE T. HEOWN, 1,L.l). , Y.K.S. J. DEWAI:, LL.D., F.E.S. WYSDHAM R. DUNSTAN, Al. A., F.B.S. €1. J. H. FESTON, M.A. :F.Et.S. C.E. GROVES, F.R.S. 1:. MEI.DULA, F.R.S. H. FOHSTEK MOHLICY, 31. il., L).Sc. A. Sco’rr, D.Sc., F.T:.S. T. E. THOEI~E, LL.U., 1C.lt.S. W. A. TILDES, I).Sc., Y.E.S. 6bitDx : IV. 1’. WYNSE, D.Sc., F.K.S. 5 II b - 6 b i t o c : A. J. GIXENAWAY. 1900, Vol. LXXVII. Part I. LUXLiOh-: GURNEY S: JACKSON, 1, PATERNOSTER ROW. 1900.RICHARD CLAY & SONS, LIMITED, LONDON & BUNGAY.J O U R N A L OF THE CHEMICAL SOCIETY, TRANSACTIONS. H. E. ARMSTILONG, Ph.D., F.R.S. HOXLACE T. BROWN, LL.D., F.R.S. J. DEWAIL, LL.D., F.R.S. WYNDHAM R. L)USS’I”AN, M.A., F.R.S. H. J. H. FENTON, M.A., F.E.S. 0. E. GROVES, P.K.S. R. MELUOLA, F.R.S. A. SC’O.I”I’, D.Sc., F.R.S. ‘L’. E. TIIOHPE, LL.D., F.K.S. W. A. TILDEN, D.Sc., F.R.S. H. FoIiSTEfi MORLEY, M.A., D.Sc. ebitnr : W. P.WYNNE, D.Sc., F.R.S. Sub-@bifor : A. J. GKEENAWAY. 1900. Vol. IXXVII. Part 11. LONDON: GURNEY & JACKSON, I, PATERNOSTER ROW. 1900.RICHARD CLAY & SONS, LIMITED, LONDON & BUNGAY.C O N T E N T S . PAPERS COAfMUNICATED TO THE CHEMICAL SOCIETY. I.-The Chlorine Derivatives of Pyricline. Part IV. Constitu- tion of the Tetrachloropyl.iclinep. By TV. J. SELL, M.A., F.I.C., and F. W. DOOTSOK, M.A. . 11.--The Dissociation Constants of very Weak Acids. Ey JAMES WALKER and WILLIAM COIWACK 111.-The Prepzmtion and Properties of Solid Ammoilium Cyanate. By JAMES WALKER and JOHN K. WOOD . IV.-Etherificatioii OF Derivatives of P-Nitphthol. By WILLIAM A. DAVIS . V--Contribution to our linomledge of the Aconite Alkaloids. I’art XV. On Japaconitine and the Alkaloids of Japanese Aconite.By WuNDmni R. DUNSTAN, F.R.S., and HAROLD 31. READ, Assistant Chemist in the Scientific Department of the Imperial Institute . VL-A RIethod of Separation of the various Isomodes con- tained in ordinary commercial Xylidine. By W. K. HODGKINSON and LEOSHARD LIMPACH . V1I.-The Oxidation of Organic Acids in Presence of Ferrous . Iron. Part I. By HENRY J. IIORSTMAN FENTON, At.A., F.R.S., and H. 0. JONES, B.A., B.Sc. . VITT1.-Oxalacetic Acid. Ry HENRY J. HORSTAIAN VENTON, M.A., F.R.S., and H. 0. JONES, B.A., B.Sc. . 1X.-Determination c f the Constitntion of Fatty Acids. Part 11. BJ’ ARTHUR WILLIAhI CROSSLEY and HENRY RONDELE SUEUR . X.-Preparation of Benzeneazo-o-nitrophenol. By J. T. HEWITT XI. -Ethyl Dibromobutanetetracarboxylate and the Synthesis By BEVAN XI1.-The Atomic Weight of Nitrogen.By GEORGE DEAN, B.A. XIII. -Formation of a- and P-Acrose from Glycollic Aldehyde. By HENRY JACKSON, B.A., Fellow of Downing College, Cambridge, of Tetrahydrofurf wan-2 : 5-dicarboxylic Acid. LEAN, D.Sc., B.A. . PAGE I 5 21 33 45 65 69 77 83 99 103 117 129iV CONTENTS. X1V.-Snbstitiitecl Nitrogen Cliloriclcs and their Rclntioii to tlic Substitiition of Hnlogcii in L4iiili(lcs :mcl Aniliiies. Port8 T 1 . ‘L’lic Trichlorophen~~l h c y l Kitrogeii Cldoi*i(les. I<y P. 1). CIIATTAWAY nn(l K. .J. P . ORTON . XV. -The Deconiposition of C’lilomtes, with Special TZcfeiencc to the Evolntion of Chlorine and Oxygen. P a r t I. 13y XV t. -The Interaction of Sulphiii*ic Acid and Potassiiiin Ferrocpiiide. By lbC!ITARD HALIM-RTON ADTE, &LA., B.Sc., and KFXDALT, COLIN BROWXISO, B.A. XVI1.-Action of Allcyl Totlides on the Mercuric Iodide Sulphides of the Fatty Series. Ey SAMJET, SMILES, B.Sc. . Victor MeFer Memorial Lectnre. Ey T. 1‘. TIIORPR, Ph.D., D.Sc., LLD., F.R.S., President of the Cliemicnl Society . XV11I.-F~lectrol~tic I’reparntion of Iiidnliiie Dyes. Ry EMERIQUE CHARLES SZARVASY, Ph.U. . X1X.-Action of Cliloroforni and Potassium Hydroxide on o-Amiiiobenzoic Acid. XX.-Anhydrous Sulpliates of the Form 2M”SO,,R,SO, ; especjally those of Isometric Crystnllisation. Ry FREDERIC R. MALLET SX1.-C-Derivatives of Hydroxytrinzole. By GEORGE YOUNG, Ph.D., and ERNEST WITHAM, B.A., F.8c. . XXI1.-Note on Volhsrd’s Method for the Assay of Silver Bullion. By THOMAS KIRKE ROSE, D.Sc.. XXII1.-The Chlorine Derivatives of Pyridine. Part V. The Constitution of Citrazinic Acid. Formation of 2 : 6-Dichloro- pyridinc and 3 : 6-IXiodoisonicotinic Acid. By W, J. SELT,, MA., F.I.C., niitl F. W. DOOTRON, M A . XXlV.-l’he Forinntion of Heterocyclic Compoiinds. By WIL1,IAM H. SOnlsArT, R.Sc. Ey ~VALTER J. ELLIOTT, M.A. . SIEGFRIED 1?UIIF:MANN alld H. E. STAPLTSTON, Scholn1* of Sh. John’s College, Oxford . XXV.-Studies in the Camphnnc Stcrics. Part T. Nitro- caml)linne. 13y MARTIN ONSLOW FORSTER . SX VI.--The Refraciive and Mngiictic Rotator!- Powers of soitie Bcnxenoicl Hydrocarbons. The Refractive Poworh of Mixtnres. An iinprorecl Speetrometer Scnlc 1to;ider. f3y W. H. PERKIN, LTJ.I>., PILD., F.R.8. , X XVI I.-The Condensation of Formnldehyclc, with 15t hy1 i\Idonate, an(1 Syiitliesis of Pentainethylene-1 : 2 : 4-tricarb- oxylic Acitl.BJ J . FRASK BOTTONLEY 2nd IT. H. €‘Emis, j u n . XXVIIT.-Action of Fiirniiig Nitric Acid on a-Dibromocam- SaIt(1r’s Fellow in tlic liesearcl~ 1,nlm.n tor!- of thc Pli:ti*mn- reiLtica1 society of Great Brihiiu p1lOl’. Ijy /LTtT€IUIt hPWORT11 :Uid EDGAR 31. (?HA!3JIAN, 134 150 160 169 207 318 21 G 224 232 233 230 25 1 267 204 309CONTENTS. v PAGE XXTX.-The A1,sorption Spectra of Aininoiiia, Methylamine, Hydroxylaiiiine, Aldoxirne, ail11 Acetoxinie. By WALTER NOEL HA~WLEY, F.R.S., niid J.\MES J. I h ~ i m , T).Sc., M.A. . XXX.--Riiimoniiiiii Ainidos~ilpli:ite. Ry HDWARD DIVERS and MASATAT~A OGAWA . XXX I.--Prodncts of Heating Ammonium Thiosulplinte, Sulphites, and Tritliionate.13y EDWARD 1)IYERS a i d MARATAKA OGAWA . XXXI1.-The Combinntion of Sulphur Dioxide and Oxygen. By EDWARD JOHX I~USSELL and NORMAN SMITH XXXII1.--Notes on the Estimation of Gaseous Compounds of Sulphur. YXX1V.-Influence of the Nascent State on the Combination of Dry Carbon Monoxjtle ant1 Oxygen. By KDWARD JOHN RUSSELL . XXXV.-Note on the Refraction and Magnetic Rotation of Hexamethylene, Chlorohex~imetliylene, mil Dichlorohexa- methylene. By SYDNEY YOUNG, D.Sc., F.X.S., :\lid EMILY c. FORTEY, . XXXV1.-Campholptic and Isolanronolic Acids. By JAMES WALKER and WILLIAM COI~MACJK . XXXVI1.-Configuration of the Camplioric Acids. By J~b1l.s WALKER and J O H N K. WOOD XXXVII1.-The Constitution of Camphoric Acid. By JAMES w-ALRER . . . XXXI X.-The Maximum Pressure of Naphthalene Vapour.By RICHARD WILLIAM ALLEN, BI. A. University College, Aucklancl, N.Z. . XL.-The Maximum Pressure of Camphor Vapour. By EICHARD WILLIAJI ALLEN, MA., University Cfollege, Auckl:tnd, N.Z. . XLL-Apiiii aiid Apigeniii. Part 11. Note on Vitexin. By ARTHUR GEORGE PERKIN, F.R.S.E. . XLI1.-Yellow Clolouriiig Principles contained in Various Tannin Matters. P a r t V I I . Arctostaphylos Uva wsi, I-lrenut ory lor L C a m p ccch ian? cm , Rh LS ,IIc t opi~ GWZ, My r i c a Gale, Coricwicc myrtifolitc, rcnd .i?obi?ria psewdacacicc. I,y ARTHUR GEORGE PERKIN, F.R.S.E. . XLllJ .-Potassium Nitrito-hydroximidosulphates and the Non- existence of Uihydroxylwuiiie Derivatives. By EDWARD DIVERS, M.D., D.Sc., F.K.S., Emeritus Professor of Chem- istry, and TAMEMASA HAGA, D.Sc., Professor of Chemistry in the Tiiky6 Jmperial TTniversity, Japaii X1,I V.-Jdentiticntion ni id Coiistitiitioii o f Freiny’s Sulphazotised Salts of Yotnssiiim.By EDWARD DrvmS an(1 TAMEMASA H.IC;A . By EDWARD JOHN XUSSELL . . . 318 327 335 340 35 2 36 1 372 374 383 390 400 413 416 423 432 440vi CONTENTS. XLV.-Cainphonic, Homocamphoronic, and Cnmphononic Acids. By ARTHUR LAPWORTH and EDaAR M. CHAPNAN, Salter's Fellow in the Research Laboratory of the Pharmaceutical Society . XLV1.-New Syntheses of Indsne. By F. STANLEY KIPPIKG, Ph.D., D.Sc., F.R.S., and HAROLD HALL, A.I.C. XLVI1.-Pilocarpiue and the Alkaloids of Jaborandi Leaves. By HOOPER ALBERT DICKINSON JOWETT, D.Sc. XLVII1.-Spectrographic Studies in Tau tomerism. The A b- sorption Curves of the Ethyl Esters of Dibenzoylsuccinic Acid.By WALTER NOEL HARTLEY, F.R.S., and JAMES J. DORRIE, M.A., 1lSc. . XL1X.-The Curves of the Molecular Vibrations of Benznati- aldoxime and Benzsynaldoxime. By WALTER NOEL HARTLEY, F.R.S., and JAXES J. DOBBIE, M.A., D.8c. By Sir HENRY ROSCOE, B.A., Ph.T)., D.C.L., LL.D., D.Sc., F.R.S., Hon. R4.D. (Heidelberg), Corresponding Member of the French Academy of Sciences, Emeritus Professor of Chemistry in Victoria University, Vice-Chancellor of the University of London . , Bunsen Meinorial Lecture. . Annual Geiieral Meeting . Obituary Notices . L.-Electrolysis of the Nitrogen Hydrides and of Hydroxyl- rtmine. By EYERIQUE CHARLES SXARVASY, Ph.D. . L 1 .-Coiistitntion of Amarine, of its supposed Dialkyl- and Diacyl-derivatives, and of Isamarine.By FRANGIB R. JAPP, F.K.S., and JAMES MOIR, M.A., I3.Sc. . LI1.-Vapour Density of Dried Mercurous Chloride. By H. BRERETON BAKER, 3I.A. . LII1.-Preparation of Pure Hydrobromic Acid. By ALEXANDER SCOTT . L1V.-A New Sulphide of Arsenic. By ALEXANDER SCOTT . LV.-Researches on the Alkyl-substituted Succinic Acids. Part 1 I. 8-Diprop3'1, a-Diisopropyl, and aa,-Propylisopropyl- succinic Acids. By WILLIAM A. BONE and CHARLES H. G. SPRANKLING . LV1.-The Interaction between Sulphites and Nitrites. By EDWARD DIVERS and TAMEMASA HAGA . LVI1.-Presence of Invertase in some Plants of the Gruminece. LVII1.-Mannogalactan and Laxulomannnn. Two New Poly- By JULIAN LEVETT BAKER and THOMAS HENRY L1X.-The Dissociation Constant of Azoiniide (Hydrazoic Acid). Part I. By JAMES O'SULLIVAN .. . saccharides. POPE . By CHARLES ALFRED WEST, Assoc.l:.C.S. . PAQE 446 467 473 498 509 513 555 59 1 603 GOS 6 46 648 65 1 654 673 691 696 705CONTENTS. vii LX.--New Glucoside froiii Willow Bark. By HOOPER ALBERT 1 ,XI.-BroniinRtion of Renzeiwazophenol. By J. T. HEWITT LX II.-Decomposition of Chlorates. Part 11. Lead Cblomte. LXII1.-Action of Iodine on Alkalis. By ROBERT LLEWELLYN TAYLOR . LXTV.-Alkylation by means of Dry Silver Oxide and Alkyl Halides. By GEORGE DEUCE LANDER, D.Sc. . JJXV.-Hydrosulphides, Sulphides, ant1 Polysulphides of Potass- ium and Sodium. LXV1.-Chlorine Derivatives of Pyridine. P a r t VI. Orientn- tion of some Chloramiiiopyridines. By JV. .J. SELL, M.A., F.R.S., and F. W. DOOTSOS, X4.A. . 1,XVII.-Note on Partidly IIiscible Aqueous Inorganic Solu- tions.By G. 8. NEWTH . LSVII1.-Racemic and Optically Active Forms of Anisrine. By H. LLOYD SNAPE, D.Sc., Ph.D. 1XIX.--Substitnted Nitrogen Chlorides mid Bromides derived from 0- and pAcetotoluidide. By F. D. CHATTAWAY and I<. J . P. ORTON . LSX’.-C)rtlio-snbstitntcc\ Nitrogen Chlorides and Rroiiiitles and the Entrance of Hnlogen into t,lie Ortho-position in the Transformation of Niti-ogeii C1iloridt.s. T3y F. P. CHATT.IWAY niid I<. J . P. ORTON , LSX1.-Nitrogen Clilor.ides clerirnble froin ~~~-Cll~lo~oncetanilide aiid their T~ansforniation. Ry F. D. CHATTAWAT, li. J. P. ORTON, and W. H. HURTLEY LXX11.--Condensation of Ethyl Acetyleiieclicarboxylate with Bases and P-Ketonic Esters. By SIEGFRIED RUHENANN and H. E. STAPLETOX, T>.A., Scholar of St.John’s Clollege, Oxford IJXXII I.--Broiiiiiiation of Benzeneazophcnol. Part 11. By fXXIV.--hctioii of E’oriii;tltlt~liytle 011 Aiiiiiies of the Naphtha- leiie Series. Part [I. By GILBERT THOMAS MORGAN, D.Sc. IXXV- Estimation of Hypoiodites and Iodates and the lteactjoii of Iodiiie 3Ionochloridc with Alkalis. Ry K. J. P, OE~TON and W. L. BLACKMAN. I~XXVI.-IItese,zrc3hes on Silicoii Compounds. Part TI. On Silicodiphenyldiiniide and Silicotripheiiylguanidine. By J XXVI1.-A Study of the Absorption Spectra of o-Oxycarbanil aiid its Alkyl Derivatives in relation t o Tautomerism. By WALTER NOEL HARTLEY, F . R . M . , JAMES J. Donnr~. D.Sc., DICKIN~ON JOWETT, D.So. . and W. G. ASTON . By WILLI~IM H. h D E A U , B.SC. . By w. POPPLEWEI.L BLoxAJr, B.Sc., . JOIIN THEODOI~E 1 h W l T T and T ~ I L L I A M (:I<ORGE ASTON . . J. EMERSON 1tEYNOLDS, D.iEk., M.D., F.R.S. nI.A., and PIIOTIOS G. 1’ALIATSEAS . PAGE 707 713 717 725 729 753 771 7 T5 789 797 so3 804 81 0 S14 830 836 S39viii CONTENTS, PAGE LXXVII1.-Ultra-violet Absorption Spectra of Some Closed Chain Carbon Compounds. Part TI. Dimethylpyrazine, Hexamethylene, and Tetrahydrobenzene. By WALTER NOEL HARTLEY, F.K.S., and JAMES J. DOBBIE, D.Sc., MA. . . 846 LXX1X.-The Constitution of Pilocarpine. Part I. By HOOPER ALBERT DICKINSON JOWETT, D.Sc. . . 851 LXXX.-Isomeric Partially Racemic Salts containing Quinque- valent Nitrogen. Parts I-VI. Hydrindamine Broino- camphorsulphonstes, Chlorocaniphorsiilphonates, and C ~ S - T - Camphanates. By FREDERIC STANLEY KIPPINO, Ph.I)., D.Sc., F.R.S. , . 861 LXXXT.-Constitution of Ethyl Sodiocynnabetate an(l of Ethyl LXXXII. --cis- and trcc?Ls-aa,pp-Tetramet hylglutaric Acids. l3y LXXXII1.-P-Isopropjlglutaric Acid and ris- and trans-Methyl- isopropylglutaric Acids. By F. 1% Howrm, JOCELYN F. LXXX1V.-The Persulphuric Acids. I3y T. MARTIN LOWRY, LXXXV.-Diruethyldiacetylacetone, Tetmmethylpyrone, ant1 Orcinol Derivatives from TXacetyIacetone. By J. X. COLLIE, F.R.S., and 13. I). STEELR, R Sc. (Melbourne), 1852 Exhibition Scholar . . 961 LXXXV1.-Dehydracetic Acid. By J. N. COLLIE, F.R.S. . 971 LXXXVI1.-Decomposition of Hydroxyai~~idosulphates by Copper Su1ph;ite. By EDWARD DIVERS and TAMEMASA HAGA 978 LXXXVII1.-Condensation of Phenols with Esters of the Acetylene Series. Part 1.Action of Phenols on Ethyl Phenylpropiolate. By SIEGFRIED RUHEMASN and FRED. BEDDOW, D.Sc., P1i.D. . 984 LXXXIX-Estimation of Furfuraldehycle. Tty WILLIAM CORMACK . . 990 Sodiomethylcy;~nacetate. By JOCELYN FIKLD THORPE . , 923 JOCELYN F. TIroRPE and WILLIAM J. YOUNG. . . 936 THORPE, WILLIAM UDATJ,, and, in part, H. A. NEALE , . 942 1>.Sc., and Jom H. WEST . . 950 Friedel Memorial Lecture. By J. M. CRAFTS, Professor . . 98.3 XC.-Diphenyl- and nialphyl-ethylenediamines, and their Nitro- derivatives, Nitrates, and Mercnrichlorides. By WILLIAM SLOAN MILLS, B.A., Demonstrator of Chemistiy in the XC1.-Researches on Morphine. Part I. By S. R. BCHRYVER XCI1.-The Oxime of Mesoxamide and some Allied Compounds. XCTI 1.-Phenylacetylchlorainine and its Analogues. By HENRY XC1V.-Derivatives of Cyanocamphor and of Homocsmphoric Queen’s College, Galway .. 1020 and FREDERIC H. LEES . . 1024 By MARTHA ANNIE WHITELEY, B.Sc. . . 1040 E. ARMSTRONG . . 1047 Acid. By AHTHUR LAPWO~~TH . . 1053PAGE X C: V . - - A ~ p r w t , r i c O1~tic;diy Artivt: Sii l p l i 111 Coiiipoultids. cl-Metl~ylethyltlretiIi~ Ylatiriic*hlori.de. By WILLIAM JACK- XCV1.-A New Methotl 0% Estimating Potassium. By R E C F I A ~ ~ D HALIRURTON ADIE and THOMAS BARLOW WOQD . . 1076 XCVII.--Notes on the C'heniistry of Chlorophyll. By LEON MARCHLEWSKI, Ph.D., and C. A. S CHUNCK . . 1080 XCVII1.-Sulvanite, a New Mineral. . 1094 XC1X.-Acetyl and Yhenacetyl Derivatives of Diethy1 &Tar- trate. By JOHN MCCRAE and T. S. PATTERSON . . 1096 C. -Estimation of Atinospheric Carbon Dioxide.By JAMES WALKER . * 1110 C1.-Periodides of Substituted Oxonium Derivatives. By J. N. COLLIE, F.R.S., and B. D. STEELE, B.Sc. (Melbourne), 1851 Exhibition Scholar . . 1114 CIL-Condensation oE Phenols with Esters of the Acetylene Series. Part 11. Action of Phenols on Ethyl Pbenylpro piolate and Ethyl hcetyleuedicsrboxylate. By SIEGFRIED C1II.-Vapour Pressures, Specific Volumes, and Critical Constants of 1 )iisoyropyl and Diisobutyl. By SYDNEY POUSG, D.Sc., F.R.S., and EMILY C. FORTEY, B.Sc. . 1136 C1V.-Vapour Pressures, Specific Volumes, and Critical Con- stants of Normal Octane. By SYDNEY YOUNG, D.Sc., F.R.S. 1145 CV.-Separation of Neobornylamine from Bornylamine. By MARTIN ONSLOW FORSTER and JAMES HART-SMITH, A.R.C.S. 1152 CV1.-Aminoamidines of the Naphthalene Series.(Third Cominunication on Anhydro-bases. ) By RAPHAEL MELDOLA, F.R.S., and LEWIS EYNON, A.I.C. . . 1159 CVI1.-Note on the Elimination of a Nitro-group during Diazotisation. By RAPHAEL MELDOLA and ELKAN WECHSLER . . 1172 CVII1.-A Contribution to the Stereochemistry of Sulphur : an Optically Active Sulphine Base. By SAMUEL SMILES, B.Sc. 1174 C1X.-Condensation of Phenols with Esters of the Acetylene Series. Part 111. Synthesis of Benzo-y-pyrone. By SIEGFRIED RUHEMANN and H. E. STAPLETON, Scholar of St. John's College, Oxford . . 1179 CX.-Contributions to the Chemistry of Hydrotetrazines and (7x1.-Isomeric Dibenzyl Ketone Benzalanilines and Deoxy- benzoin Benzalanilines. Part 11. By FRANCIS E. FRANCIS, Ph.D., B.Sc., Lecturer in Chemistry, University College, Bristol .. . . 1192 sox POPE and khANLISY JOHN 1'EActrEY . . 1072 By G. A. GOYDER . RUHEMANN and FRED. BEDDOW, D.Sc., Ph.D. . . 1119 . Triazoles. By OSWALD SILBERRAD, Ph.D. , . 1185X CONTENTS. PAGE CXI1.-Condensation of Rlethyl Ac~tonedicarboxylate. Con- stitution of Orcinoltricarboxylic Esters. By k'. W. CXIT1.-Contribution to the Chemistry of the Aroiiiirtic Metn- CX1V.-Action of Aromatic Aldehydes on Derivatives of P-Naphthylamine. By GILBERT THOMAS MORGAN, D.Sc. . 1210 CXV.-Action of Hydrogen Peroxide on Carbohydrates in the Presence OF Ferrous Salts. 11. By RUBEXT SELBY MORRELL, M.A., Ph.D., and JAMES MuimAY CROFTS, M.A., B.Sc. . 1219 UXV1.-The Hydroxyphenoxy- arid Yhenylenedioxy-acetic Acids. By W. CARTER aid W. r l ' ~ ~ ; ~ ~ l t LAWRENCE, B.A., Ph.l>.. 1222 CXVI1.-Specific Gravities of the Halogens a t their Boiling Points, and of Oxygen and Nitrogen. By JULIEN T)RUGE/IAN, Ph.D., and WILLIAM RAMSAY, F.R.S. . . 1228 CXVII1.---Hydroferrocyanic Acid. By KEND ALL COLIN CX1X.-The Nature of Metal-aiuiuonia Compounds in Aqueous Solution. Part I. By H. M. DAWSON and J. MCCRAE . 1239 CYX.-Action of Alkalis on the Nitro-compounds of the Paraffin Series. Part 11. Reactions and Constitution of . Methazonic Acid and the Mode of Formation of Isoxazoles. By WYNDHAM It. DUNBTAN, F.H.S., and ERNEST GOULDING, B.Sc. . . 1262 ClXXI.-Arnount of Chlorine ill Rniu Water collected at Cirencester. By EDWARD KINCH, Royal Agricultural College, Cirencester . . 1271 CXXI1.-Hexachlorides of Benzonitrile, Benzainide, and Benzoic Acid. By FRANCIS EDWARD MATTHEWS . , 1273 Nilson Memorial Lecture. By OTTO PETTERSSON, Professor of Chemistry in the University of Stockholm . . 1277 CXXII1.-Degradation of Glycollic Aldehyde. By HENRY J. HORSTMAN FENTON, M.A., F. R.S. , 1294 CXX1V.-Researches on the Alkyl-substituted Succinic Acids. Part 111. Dissociation Constants. By WILLIAM A. BONE and CHARLES H. G. SPRANKLING . . 1298 CXXV.-Genistein. Part 11. By ARTHUR GEORGE PERKIN, F.R.S.E., and LOUIS HUBERT HORSFALL . . 1310 CXXV1.-Luteolin. Part 111. By ARTHUR GEORGE YERKIN, F.R.S.E., and LOUIS HUBERT HORSFALL . . 1314 CXXVIL-Contributions to the Knowledge of Fluorescent Compounds. Part I. The Nitro-derivatives of Fluorescein. DOOTSON, M.A. . . 119(i diainines. By GILBERT THOMAS MORGAN, D.8c. . . 1202 BROWNING, B. A. . 1233 By JOHN THEODORE HEWITT and BRYAN W. PERKINS . . 1324

ISSN:0368-1645    

DOI:10.1039/CT90077FP001

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

T H E DISSOCIATION CONS‘L’ANTS OF VERY WEAK ACIDS. 5 By JAMES WALKER and WILLIAM CORMACK. ALTHOUGH the dissociation constants of many hundreds of organic acids have been measured, chiefly by Ostwald and his pupils, the feeble inorganic acids have been practically neglected in this respect. We are, in consequence, without accurate knowledge of the relative strengths of such common acids as carbonic acid, hydrocyanic acid, sulphydric acid, and boric acid, either relatively to each other or to acetic acid, which may be taken as the typical “weak” organic acid with a definite afinity constant. It is the object of the present com- inunioation to supply the necessary data for filling up this blank. The Appccrcctus and Mode of Experiment. As most of the acids investigated were gaseous a t the ordinary tem- perature, a closed form of apparatus had to be devised, which would permit of the solutions being diluted to definite strengths without communication with the air.I n a vessel of the usual type, the loss of gas is very rapid, and accurate dilution is impossible. After several preliminary experiments, the principle finally adopted was that of the syringe. The electrodes were placed a t the bottom of a long tube provided with a piston, which, by its regulated withdrawal, could be made to suck into the tube a measured quantity of the water used for dilution. A sketch of the whole apparatus is given in Fig. 1. The principal tube A was 46 cni. long and 2.2 cm. in diameter. The stem P was made of a glass tube of external diameter only slightly smaller than the bore of A , and was closed at the lower end by a rubber stopper R, which formed the piston, and fitted closely to the walls of A .The external tube was closed at its lower extremity by a perforated rubber stopper provided with slits for the passage of the wires from the electrodes EE. These wires were soldered to copper wires WW, which made connection with the rest of the apparatus through the mercury cups MM, As the tube A was immersed in water for a t least three-fourths of its length in order that a constant temperature might be secured, great care had to be paid t o the insula- tion of the wires from the electrodes, as the conductivity of the water in the thermostat was much greater than the conductivity of the solu- tions investigated.The connections are shown on a larger scale in Fig. 2. The copper wires leading to the mercury cups were covered with gutta-percha, and, as an additional precaution, were surrounded by tight-fitting glass tubes throughout the whole length immersed in the water. The connections, together with the lower end of the6 WALKER AND CORMACK : THE DISSOCIATION tube and the stopper, mere embedded in paraffin wax, a shopt piece of wide rubber tubing being slipped over all before the parafin wax had set. When the apparatus thus protected was placed in ordinary tap water, no current between the wires could be detected with an induc- tion coil and telephone (compare Ostwald, Physico-chemicaZ Mensure- melnts, p. 222) if no liquid were inside the apparatus, The apparatus was filled in the following manner with the solution to be investigated, A bent tube Twas introduced into one of the holes in the stopper so that connection might afterwards be formed FIG.1. FIG. 2. with the measuring vessel N by means of a short piece of rubber tubing provided with a clip. The syringe was now inverted, and the piston withdrawn, so as to leave a little more than 20 C.C. clear space above it. By means of a pipette or burette, 20 C.C. of the liquid to be examined were delivered into the apparatus through the other hole in the stopper, which was then closed by a glass plug, the piston being thereafter forced upwards until the liquid reached the end of the tube 2'. The measuring tube N, which, together with the connection tube, had been previously completely filled with water, was now attached toCONSTANTS OF VERY WEAK ACIDS.7 T, communication between the two vessels being prevented by the pinch-cock C. Both the rubber tube and bent glass tube were chosen of narrow bore so as to prevent mixing of the liquids when the pinch-cock was open. The wliole apparatus was now placed in the upright position in a thermostat containing water a t 18", a t which temperature all measurements in this paper were made. The thermo- stat consisted of a tall enamelled cylinder of about 20 litres capacity, the outer vessel, of a steam steriliser being found very suitable. The mercury cups JfX were fixed in a coppey stage fastened to the rim of the thermostat. The measurements were made mi th induction currents and telephone in the manner described by Kohlrausch and Holborn (Leitvernzogen der EZelctroZyte).For the weakest acids measured, the electrodes were not platinised ; for stronger acids, like carbonic acid, they were platinised with Lummer and Kurlbaum's solution. I n order t o wash the electrodes free from conducting substances after platinisation, we first of all electrolysed a solut,ion of sodium acetate between them as recom- mended by Walker and Hambly (Trans., lS97, 71, 63), after which no difficulty was experienced in rendering them fit for use in a few hours by treatment with water. All the rubber parts of the apparatus were subjected t o the prolonged action of water before being used, and did not affect the conductivity of the purest water we employed during the time necessary for completing a series of dilutions. After the first me:rsurement of the conductivity had been made, the solution was diluted by the addition of 20 C.C.of water, which was admitted by opening the clip C and the stopcock of the measuring tube (a Schiff nitrometer), the piston being then carefully withdrawn until the level of the water in the measuring tube reached the 20 C.C. mark. The clip and stop-cock wcre then closed, and the diluted solu- tion thoroughly mixed by inverting the conductivity vessel several times. The mixing was effected by the glass float Pof approximately the same specific gravity as water. The apparatus was then replaced in the thermostat, and a reading of the conductivity made when tem- perature equilibrium had been established.The solution was again mixed and another reading taken. If this differed from the first, the operations were repeated until a constant value was obtained, which occurred, as a rule, in less than fifteen minutes. The dilution was now continued by the addition of another 20 C.C. of water in the manner previously described, the level of the water in the nihrometer now standing a t the 40 C.C. mark. I n this way, four t o five dilutions by successive increments of 20 C.C. could be made in little more than an hour, without the solution coming in contact with the air during the process.8 WALKER AND CORMACK : THE DISSOCIATION Prepccration of the Whter used f o r Dilution. We found no difficulty in obtaining a supply of water with a con- ductivity of 0.7 x 10-6 in Siemens units, at ISo, by three successive distillations, namely, with alkali, with phosphoric acid, and, finally, with- out the addition of any chemical.The last distillation is the most im- portant, and must be conducted in a room containing no volatile acids or alkalis, the atmosphere even of a well ventilated chemical laboratory being fatal to the preparation of water of the above quality. I n this last distillation, the water was condensed in a tin pipe, the end of which passed through the rubber stopper of a bottle which was further provided with a glass syphon tube and a long, narrow inlet tube for air. I n this bottle, the water suffered no deterioration in quality even when kept for several days. It is essential, if weak acids are to be investigated, that the conductivity of the water used for the prepara- tion and dilution of the solutions should not exceed the above value, otherwise errors of unknown magnitude are introduced into the deter- minations of the conductivity. The conducting power of water of the conductivity 0.65 x is due to dissolved carbonic acid almost entirely, and it will be shown in the sequel that the error thereby introduced into the conductivity of other weak acids is not only very small, but can be estimated and eliminated with moderate accuracy. Carbonic Acid.When carbon dioxide dissolves in water, the solution produced possesses a considerable electrical conductivity, indicating the forma- tion of the acid H,CO,. The conductivity of such solutions have already been measured by Pfeiffer (Ann.Phys. CAem., 1884, 23, 625) and by Knox (ibid., 1895, 54, 44). The solutions studied by Pfeiffer were prepared under pressure, and are therefore somewhat too con- centrated to be of service in fixing the dissociation constant of carbonic acid; the solutions invastigated by Knox, on the other hand, are suEciently dilute to permit of a constant being calculated, although Knox did not seek to perform the calculation himself. KLIOX’S results are given in the following table, the letters bearing their usual signification, namely : v-Dilution, or number of litres in which 1 gram-molecule is p = Molecular conductivity. rn = Proportion of acid dissociated. contained. nG k = Dissociation constant, or the value of the expression - ( I -m)v’CONSTANTS OF VERY WEAK ACIDS.9 I n cnlcu1:tting the dissoci;ited proportion, the molecular conduc tjivitJy of carbonic acid at infinite dilation mas made equal to 536 at 1 8 O , the data used in fixing this number being given below. ?J . 12-61 14.54 18.43 24.9 36.36 53.2 74.3 125 287 1099 p. A 0.731 0.78'3 0.877 1.025 1.233 1.487 1.756 2.300 3,520 7.540 711. 0.002 17 0 4 0 2 35 O.OO86 1 0.00305 0 -003 6 7 0.00443 0.00523 0.00684 0.01048 0.02244 IF. c) .0,37G 379 3iO 375 372 37d 3 'TO 377 386 469 The constancy of the expression k for a tenfold increase in the dilution leaves nothing to be desired. At the two greatest dilutions, the constant increases rapidly owing to the conductivity of the water used in preparing the solulions, for which no correction has been made in the calculation. Before beginning our own experiments on the conductivity of carbonic acid, we made a series of measurements on the conductivity of solutions of sodium hydrogen carbonate, in order to obtain the data necessary for the calculation of the conductivity of carbonic acid at infinite diiutiou.As i t was possible that the sodium hydrogen salt might undergo some degree of hydrolysis at the greatest dilutions we investigated, two series of experiments were made. I n one set, the solution was diluted with water in the usual manner by means of pipettes. I n the other set, the diluent employed vats a solution of carbonic acid, in order that the extent of hydrolysis might be reduced (compare Bredig, Zeit. p1ysik:aZ. Chem., 1894, 13, 214). Both sets yielded practically the same result, as indeed might have been ex- pected, the magnitude of the dissociation constant of carbonic acid indicating that the extent of hydrolysis of sodium hydrogen carbonate would not exceed a fraction of a per cent.even a t the greatest dilution we investigated. The molecular conductivities here, as throughout this paper, are expressed in Siemens units, a O*O2-normal solution of potassium chloride with molecular conductivity equal to 11 2.2 a t 1 So having been taken as the standard of reference. * The molecular conductivities in the abstract of Knox's paper (Zeit. physikal. Cheem., 1895, 17, 186) have been reduced to half the true value by an inadvertence in the recalculation ; the dissociation constant given there is consequently erroneous.10 WALIZER AND CORMAClZ : THE DISSOCIATION V.32 64 12s 256 512 P. 65.6 68.6 71.1 73.9 76-0 These numbers point t o a conductivity of 79.5 for sodium hydrogen carbonate a t infinite dilution (compare Bredig, Zoc. cit., 198). Sub- tracting from this total value the number 41.5 for sodium (Kohl- rausch), we are left with the value 38 for the ion HCO’,. To this we must now add the value 298 for the hydrogen ion (Kohlrausch), and thereby obtain the number 336 as the molecular conductivity of carbonic acid, H*HCO’, a t infinite dilution. The carbonic acid used by us was prepared from marble and hydro- chloric acid, and was washed by passing through two wash-bottles and finally a Geissler potash bulb all filled with pure water. The gas was then bubbled through water of minimum conductivity con- tained in a carefully cleansed bottle.To estimate the concentration of the solution thus obtained, we employed Pettenkofer’s method, the titrations being made with fortieth-normal solutions of bargta and hydrochloric acid. The following table gives the conductivity results for carbonic acid solutions prepared in this way : Caybonic acid, H2C0,, fvom mcwbke. 2). P- 911. k. 31.25 1.038 0.00309 0*0,306 62.5 1.475 0.00439 309 93.7 1.800 0.00536 308 125 2 -083 0 -00 6 20 309 Mean.. . . . . . . .0.0,308 As a very slight amount of impurity, say hydrochloric acid, would considerably affect the conductivity of a weak acid such as carbonic acid, another solution was prepared by passing the gas generated by the slow evaporation of solid carbon dioxide, first through pure water to wash it, and then through water of minimum conductivity.In this way, it was thought that the presence of all conducting impurities would be avoided. As the subjoined table indicates, practically the same numbers were obtained as for carbonic acid from marble.CONSTANTS OF VERY WEAK ACIDS. 11 Cwrboxic cccid, l12W3, jrom solid c a d m i dioxide. 21. lu. 111. k. 27.5 0.972 0 -00 2 8 9 0*0,305 55.0 1.368 0.00407 303 82.5 1.679 0*00500 304 110.0 1.930 0.005’75 302 Mean.. , , . , . . .0*0,304 The value of the constant ca,zulated from our experiments is thus about 20 per cent.. less than t’he value calculated from Knox’s numbers, corresponding to an actual difference in the conductivity of 10 per cent. I n view of the small conductivity of the solutions investigated, this difference cannot be said to be excessive, and is probably to be accounted for as follows.In the first place, the water which we used for the dilutions was of distinctly bett,er quality than that employed by Knox, the conductivity of which varied from 0.95 x lodG to 2.6 x 10-6, and was especially large for the most dilute solutions where its proportionate infliience is greatest. Thus at the dilution 125, the conductivity of the water amounted to 1 2 per cent. of the total con- ductivity of the solution. It is clear, therefore, that this alone might go a long way in accounting for the larger numbers obtained by Knox. The mode of measuring the concentration of the solutions was also different in the two cases. Whilst we used a chemical method for estimating the carbonic acid in the solutions examined by us, Knox determined the amount dissolved by measuring the pressure of carbon dioxide with which the solution was in contact, and then calculating from Bunsen’s absorption coeficient for 18’ by means of Henry’s law.Now Bunsen’s number may ‘be affected by an error of several per cent., as a reference to his paper (Liebig’s Annalen, 1855, 93, 1 ) will show, and it is by no means certain that Henry’s law is accurately true throughout the range of pressures considered. -We are theref ore dis- posed to adhere to our own numbers as being probably the more accurate, notwithstanding the satisfactory constancy of the expression k exhibited when Knox’s values are used in the calculation. Conductivity of Wuter Distilled in Air.On the assumption that Henry’s law was valid, and that the con- ductivity varied inversely as the square root of the dilution, which is very nearly the case for carbonic acid, Knox calculated what the con- ductivity would be if the water was saturated with carbon dioxide a t a pressure equal t o the partial pressure of the gas in atmospheric air. The result given in his paper, viz., 0.56 x 10-6 in reciprocal Siemens units,12 WALKER AND CORMACK : THE DISSOCIATION is, however, erroneous, owing t9 nn arithmetical error in the last equation (Zoc. c i t . p. 57). The correct number deduced from his data is 0.725 x 10-6. A more accurate value can be calculated from the dilution formula, f i t 2 k=- (1 - nqv' as follows. A t 1 8 O , the dilution of a solution saturated with carbon dioxide at a pressure of 760 mm.is, according to Bunsen's absorption data, equal to 24 litres. If the partial pressure of carbon dioxide in air is 0.0003 atmosphere, the dilution of a solution saturated a t this pressure will be 24/0*0003 = 80000. If, then, in the above equation we substitute 0*000000304 for L and SO000 for v, we obtain m=0.144, that is, 14.4 per cent. of the carbonic acid dissolved from normal air by pure water is dissociated into the ions H* and HCO',. From the degree of dissociation m we obtain the molecular conductivity p by multiplication with 336, the maximum molecular conductivity of car- bonic acid a t 1 8 O . From this value, namely, 48.4, we obtain the specific conductivity on dividing by the dilution in cubic centimetres, so that we have the conductivity 4S*4/80,000,000 = 0.605 x 10-6 for water which has been in contact with the atmosphere a t 18".It is highly improbable that Henry's law in an unmodified form can be applied with propriety to such a case as that discussed above. From the study of analogous cases, it appears much more likely that the con- centration of the gas in the air bears a constant ratio to that of the undis- sociatedportion of the dissolved gas, rather than to the concentration of the total dissolved gas. The dilution of the undissociated portion 1 - na thus becomes 80000, and the dilution of the whole gas dissolved 69000. Calculating in the same manner as above described, we obtain the value 0.65 x for the conductivity of water which has been in contact with air.If we use the const,ant derived from Knox's numbers, the values become 0.67 x and 0.71 x 10-6 for the un- modified and modified forms of application of Henry's law respectively. Kohlrausch (Zeit. phgsikal. Chem., 1894, 14, 321) found that water prepared in a vacuum and of conductivity 0.11 x gained in con- ductivity on being left in contact with the air until the value 0.60 x was reached. It is also stated by Kohlrausch and Holborn (Zoc. cit., p. 111) that the lowest conductivity obtainable for water dis- tilled in air is 0.65 x 10-6. It will be seen that these values are in excellent agreement with those calculated from our experiments, so that we may assume with confidence that carbon dioxide is the only substance in the atmosphere which confers conductivity on water.CONSTANTS OF VERY WEAK ACIDS.13 State of Carbon Dioxide in Aqueous Solution. I n what has been said above, it is assumed that all the dissolved carbon dioxide exists in the aqueous solution as carbonic acid, H,CO,. This is by no means necessarily the case, for a large proportion might exist in the solution as carbon dioxide without entailing any alteration in the apparent dissociation constant. We may suppose, for example, that only half of the dissolved carbon dioxide exists in the solution as H,CO, and its dissociation products K* and HCO’,. If v, as before, represents the volume in which 1 gram-molecule of the carbon dioxide is dissolved, irrespective of the condition it assumes in the dissolved state, the dilution formula becomes since the quantity of H,CO,, which was formerly 1, is now only 4.Now, in solutions of this strength which we investigated, m does not amount to more than 0.006, so that we can write the dilution formula in the form k nt2 - _ - V without sensible error. in the solution as H,CO,, this formula becomes If only half of the dissolved gas is contained We have therefore Ic’ = 2k. The real dissociation constant of the acid H2C0, would therefore, in this case, be twice the apparent dissociation constant, namely, equal to 0*0,608. I n general, if 1/n represents the fraction of the total dissolved carbon dioxide which exists in the solution as H,CO,, the dissociation constant for the acid will be nk, where k is the apparent dissociation constant calculated from our experiments.What is here stated holds good, however, only for moderate degrees of dilution and for moderate values of n, for as soon as nz becomes of dimensions approaching those of l/n, the simple formula can no longer be applied. We have assumed above that the proportion of the dissolved gas which remains as (30, is constant and independent of the dilution of the solution. This assumption is justifiable, since the active mass of the solvent water must remain sensibly constant for dilute solutions, and the quantity converted into H,CO, will therefore be proportional t o the quantity dissolved. It is possible, however, that t.he equi- librium is: between the CO, in solution and the wzdissocicctetl H,CO,, ilot14 WALKER AND CORMACK : THE DISSOCIATION the whole amount of H,C03 and its dissociation products.For moderate dilutions and moderate values of n, this latter assumption in no way alters the deductions given above. Since we obtain a constant value of 7c for dilutions up to 125 litres, the value of m cannot be very great-cannot, for instance, well be more than 5, for otherwise Ostwald’s dissociation formula would not be applicable in its simple form.. The agreement, too, between the actual and calculated values of the conductivity of water which has absorbed carbon dioxide from normal air points to the value of n, being small, probably not greater than 2. We may take it, then, as fairly certain that when carbon dioxide dissolves in water, at least half of the dis- solved substance exists in the form of the acid H,CO,. It is only the apparent dissociation constant which is of interest to US, however, for it is that which enables us to calculate the strength of carbonic acid in solution as an accelerator, as a conductor of elec- tricity, or as competing for a base against other acids.A knowledge of the real constant, and of the constant regulating the equilibrium, H,O + CO, = H,CO,, would be of undoubted theoretical interest, but for practical purposes and ordinary solutions, the apparent constant supplies us with all the information necessary for the treatment of problems likely to occur. IIyclrogeiz Su Zphide. I n 1885, Ostwald determined the conductivity of hydrogen sulphide, and found that it was very small. No constant can be calculated from his numbers, however, as at that date the influence of the quality of the water employed in making the solutions was insufficiently under- stood.We therefore made several determinations with the best water we could obtain, and with hydrogen sulphide as free as possible from foreign conducting matter. The hydrogen sulphide was prepared by the action of hydrochloric acid on a very concentrated solution of pure sodium sulphide, and was subjected t o no other purification than thorough washing with water, the final mashing taking place through water contained in a Geissler potash apparatus. If the hydrochloric acid is added at such LZ rate that the disengagement of hydrogen sulphide is slow and steady, the method gives a product of constant conductivity. The strengths of the solutions thus prepared were estimated by adding a measured quantity of the solution to a known excess of silver nitrate solution, filtering, and determining the amount of silver in the filtrate by Volhard’s method.The maximum conductivitly of hydrogen sulphide, treated as theCONSTANTS OF VERY WEAK ACIDS. 15 monobasic acid HoHS, was fixed by means of measurements of the conductivity of sodium hy drosulphide, NaHS (Walker, Pvoc. Roy. 8oc. Edin., 1893-4, 255). These measurements give 58 as the ionic rate for HS', and therefore 356 as the maximum conductivity for hydrogen sulphide at 18". H@rogen sulphide, H*HS'. V. F- m. k. 25 0.426 0.001 19 0*0,572 50 0.599 0~00168 568 75 0.731 0*00205 562 100 0.854 0*00240 577 125 0944 0-002G5 56s Mean.. . . . .0*0,569 Another similar set of experiments a t somewhat smaller dilutions gave the mean value 0*0,574, which is practically identical with the former result. Since the impurity in the water used for dilution is carbonic acid, the dissociation constant of which is known, it is possible to correct the individual values of the conductivity by using the dissociation equations for the separate acids. As Lthe correction in this case, however, is of very small dimensions, it may be neglected without sensible error. An example of the method of calculation employed in the correction will be given when the conductivity of phenol is under consideration. Hydrocyanic Acid. We are again indebted to Ostwald for measurements of the electric conductivity of hydrocyanic acid. H e found the conductivity t o be considerably smaller than that of hydrogen sulphide, but, as before, his numbers are not sufficiently accixrate to permit of the calculation of a dissociation constant, owing to the uncertain correction for the conductivity of the water employed as solvent.I n our experiments we used water of conductivity not exceeding 0.65 x lowG, and even with water of this quality experienced much difficulty in obtaining satisfactory solutions. The method me finally adopted for preparing solutions OF hydrocyanic acid was first t o prepare a liquid acid very nearly free from water, and then allow the vapour of this to pass slowly into the water of minimum conductivity, The liquid hydrocyanic acid was obtained by gently heating a mixture of potassium ferrocy anide nud glacial phosphoric acid with an equal bulk of wnher, and condensing the vapour in a cooled dis- tilling flask.When x sufficient quantity had been collected, the16 WALKER AND COHMACK : THE DISSOCIATION distilling flask mas disconnected from the generating apparatus and attached t o a delivery tube which dipped beneath the surface of the water used as solvent. As the conductivity of the hydrocyanic acid was very small, the solutions were made as strong as was consistent with the theoretical possibility of obtaining a constant value for the expression k. J t was found that non-platinised electrodes gave better results than those which had been platinised. Kohlrausch has shown that the molecular conductivity of potassium cyanide in concentrated solutions (normal and semi-normal) is inter- mediate between the molecular conductivities of equivalent solutions of potassium chloride and potassium iodide.As these two salts have practically the same molecular conductivity for infinite dilution, it was assumed that the conductivity of potassium cyanide would have a maximum value equal to 121.6, which gives 60 for the ion CN’ and 358 for the conductivity of HCN a t infinite dilution. The concentration of the original solution was determined with silver nitrate solution according to Liebig’s method. Hydrocyanic ucicl, H*CN’. V P nz k a 0.0183 0.00005 12 0*0,131 4 0.0262 738 133 8 0.0320 894 133 16 0.0365 1019 130 Mean.. . . . 0*0,132 Another set of experiments gave a mean value of 0*0,14, and several preliminary experiments gave still higher values.We have chosen the smallest value as being the most probable, owing to the fact that any possible impurity would increase the conductivity and thus the constant. The constant as it stands is probably still too high, for even the presence of the carbonic acid in air-saturated water would effect an increase of about 2 per cent. on the mean value. Boilic Acid. Kahlenberg and Schreiner (Zeit. physikuZ. Chem., 1896,20, 547) have shown that in all probability only one boric acid exists in solution, namely, H,BO,, and that in dilute solutions the only stable salt is of the type NaH,B03. From their conductivity numbers, it would appear that the maximum conductivity of the salt Na.H,BO3 is about 75.0 at IS0. Now this number is certainly too great, as Shields has provedCONSTANTS OF VERY WEAK ACIDS.17 that a decinormal solution of borax is hydrolysed to the extent of one- half per cent. The conductivity of the sodium hydroxide produced by the hydrolysis is much greater than that of an equivalent solution of the boric acid salt, so that we must make a deduction of at least 3 per cent. in order t o obtain an approximate value of the maximum con- ductivity of the non-hydrolysed salt ; this would lead to R value of somewhat more than 72. In order to check this result, we made a series of determinations of the conductivity of the salt at 18O, using a 0.025-normal solution of boric acid as dilution liquid in order to diminish the hydrolysis. From our experiments, we deduced the value 71.5 as the maximum conductivity of the salt NaH2B0,, supposing hydrolysis to be absent.This value would give 328 as the maximum conductivity of the acid H,BO, if the dissociation is into theions H* and H,BO',. The boric acid we employed in our experiments was thrice recrystal- lised from pure water in a platinum vessel, and the solution made up by weight. The electrodes used in the final experiments were not platinised, but platinisation did not seem to affect the accuracy of the method or alter the numbers obtained. Boric acid, H*H,BO',. 9. P- rn. k. 11.1 0-0450 0*0000137 0.081 70 22.2 0.0636 194 169 33.3 0,0783 239 171 44.4 0.089 1 272 166 Mean ............ 0'0,169 Another set of experiments yielded the mean value 0.08170. This constant is of the same magnitude as that for hydrocyanic acid, and a similar correction would have t o be applied to eliminate the effect of the conductivity of the carbonic acid in the water employed for dilution. Bock (Ann.Phys. Chem., 1887,30, 638) made some observations on the electric conductivity of boric acid solutions at lao, but the solu- tions he employed were stronger than ours, and the results he ob- tained do not yield a value for k which is even approximately constant. If, however, we take his most dilute solution, which is comparable with our strongest solution, we obtain the following : V. CC. m. k. This value is in excellent accordance with that obtained in VOL. LXXVII. C 8 0.0386 0.0000118 0.081 74 own experiments. our18 WALKER AND CORMACK : THE DISSOCIATION Phenol. Bader (Zeit.physikal. Chent., l890,6, 289) has given numerous data for the conductivity of the phenols and their substitution products. Many of the substitution products yield definite dissociation con- stants, but this is not generally the case with the simple phenols themselves. Thus he obtains for phenol, C,H,*OH, the following values at 25’ : 9. P* k. 60 0.23 077 100 0.41 120 Here the value of the expression k varies greatly, a fact which is possibly due to the character of the water employed in the dilutions. Bader gives no figures from which we can judge the quality of this water. As we suspected that Rader’s numbers for phenol were considerably too high, we determined the conductivity of as pure a solution as we could produce, A quantity of colourless crystallised phenol was shaken up in a stoppered cylinder with successive small quantities of pure distilled water in order to remove any conducting substance which the phenol might contain.A solution of this purified phenol was then made up by weight, the phenol being assumed to have taken up 26 per cent. of water, in accordance with the experiments of Alexkeff. 25 0.1 4 0*0,056 The results we obtained were as follows : t’ . Pa 10 0.0132 m. 0*000041 It will be seen that this value is only about one-tenth of that ob- tained by Bslder for the molecular conductivity under corresponding conditions of temperature and dilution. Rut this value must itself be too great. The specific conductivity of the water used to prepare the solution was 0.65 x 10-6, the specific conductivity of the solution being only twice this magnitude, namely, 1-32 x 10-6.We are not justified in assuming, however, that the conductivity of the phenol is equal to the difference of these two numbers, for if carbonic acid is the impurity present in the water, each acid will lower the dissocia- tion, and therefore the conductivity, of the other, so that the cor- rection will not be so large as at first sight appears. The mode of correction is as follows. For the maximum conductivity of phenol, we have the number 322 according to the rule established by Ostwald for organic acids. The degree of dissociation of the phenol solution is therefore 0.000041 if we take the uncorrected conductivity. The concentration of theCONSTANTS OF VERY WEAK ACIDS. 19 hydrogen ions is therefore one-tenth of this, namely, 41 x and this number is practically correct, since the hydrogen ions are responsible for at least seven-eighths of the conductivity, and the difference in the speeds of the carbonate and phenolate ions vanishes in comparison.The equilibrium in the case of carbonic acid is regulated by the equation (H ions) x (HCO, ions) - - - 3.04 10-7, (H,CO,) the quantities in brackets indicating concentrations in gram-molecules per litre. Now the total concentration of the carbonic acid dissolved from the air is 125 x 10-7 in the same units. If n is taken to repre- sent the concentration of the HCO, ions, we have thus the equation 41 x x ,n - = 3-04 10-7, (125 x lO-T)--n whence n = 9 x 10-7. The number of hydrogen ions coming from the carbonic acid in the water is therefore 9 x 10-7.This deducted from the total concentration of hydrogen ions leaves 32 x 10-7 as the con- centration of hydrogen ions derived from the phenol, so that this number also represents the concentration of the C,H,O ions. Now the product of the hydrogen and phenolate ions in the above solution must be equal t o the product of the same magnitudes for a solution of phenol in water free from carbonic acid. If d therefore represents the concentration of dissociated phenol in the pure solution, we have d2 = 41 x 10-7 x 32 x 10-7 d== 36 x 10-7, whence we obtain as the degree of dissociation of a pure decinormal solution of phenol, n = 0*000036 instead of the uncorrected value, Om000O4l. Using this corrected value, we find k = 0*0,13 as an approximate value of the dissociation constant of phenol, that is, about one-fortieth of Bader’s smallest value of k.Acetylene. Jones and Allen (Amer. CAem. J., 1896, 18, 1 ) give numbers for the conductivity of acetylene which are very much too high, probably as the result of some arithmetical error. The values they obtained when recalculated from equivalent into molecular weights indicate that acetylene is a stronger acid than acetic acid, which is certainly not the case. We made a single experiment in order to determine the magnitude of the conductivity of aqueous solutions of acetylene. The acetylene c 220 THE DISSOCIATION CONSTANTS OF VERY WEAK AClbS. was prepared from calcium carbide and purified by washing in suc- cessive bottles containing silver nitrate solution, the gas being there- after thoroughly washed with pure water.A small quantity of pure water was then saturated with the gas a t the atmospheric pressure. Since water dissolves about its own volume of acetylene a t the ordinary temperature, the dilution of the solution thus obtained would be approximately 23, a number which we confirmed by precipitating with ammoniacal silver nitrate, filtering, and titrating the excess of silver in the filtrate with ammonium thiocyanate. The conductivity of this solution was only one-fourth greater than that of the solvent water, and this slight rise might conceivably be due in great part to the presence of a trace of some conducting impurity. We must there- fore conclude that acetylene has very feeble acid properties, its dissociation constant being less, and in all probability much less, than that of phenol.Xurninar y . The following table contains the dissociation constants of the acids which we investigated, the constant of acetic atid being added for comparison : Acid. k x lolo. Acetic .............................. 180000 Carbonic ........................... 3040 Boric ................................. 17 Hydrocyxnic ........................ 13 Phenol ............................. 1.3 Hydrogen sulphide ............... 570 A better idea of the relative strengths of the acids, however, may be formed from the subjoined table, which shows the percentage dis- sociation of the acids in decinormal solution. The numbers for hydro- chloric and acetic acids are derived from the data given by Kohlrausch and Holborn (Zoc.cit.), the numbers for the other acids being calculated from the dissociation constants found by ourselves. Pewentage degree of dissociation in decinormcc! solution. Acid. Acetic ................................ Carbonic ................................ Boric .................................... Hydrocyanic.. ....................... Phenol ................................ Hydrochloric .......................... Hydrogen sulphide .................. 100 m. 91.4 1.30 0.1 74 0.075 0.01 3 0.01 1 0.0037YREPARATIOK AND PROPERTIES OF SOLID AMMONIUM CYANATE:. 21 These numbers, inasmuch as they are proportional to the avidities, give a practical indication of the strengths of the acids. Thus, if acetic and carbonic acid compete for a monacid base, all three sub- stances being in molecular decinormal solution, the base will be shared between the acids in the ratio 1.3 : 0.174, that is, the acetic acid will take eight parts of the base for one taken by the carbonic acid. Again, if carbonic acid and hydrogen sulphide compete in equivalent quantities for an equivalent of R base, the carbonic acid will take seven-tenths, and the hydrogen sulphide three-tenths. In the extreme case of hydrochloric acid competing against phenol in decinormal solu- tion, the phenol gets only 1 part in 22000. For acids weaker than acetic acid, the degrees of dissociation are in the ratios expressed by the above table for practically all dilutions, since they are, in fact, proportional to the square roots of the dissocia- tion constants. All the acids in the table have been treated as monobasic acids, so that molecular quantities are always considered, not equivalent quantities. We are justified in proceeding thus, for each acid in competing with mother acid for a n insufficient quantity of a base, behaves in the first instance as a monobasic acid. Possibly the assumption would not be quite accurate for the case of carbonic acid competing for a n equivalent of base against phenol, but where the polybasic acid is the weaker of the competing pair, the assumption is in every case justifiable. As to the probable accuracy of the numbers, it may be said that the conductivities and constants €or the weakest acids are undoubtedly somewhat too high. We are of opinion, however, that the error is in no case very considerable, for our results are in close agreement with the hydrolysis determinations of Shields (€‘Id. Mag., 1893, [ v], 35, 365), data now being available for the comparison of the two methods. A discussion of this connection between the conductivities of the weak acids and the extent of hydrolysis of their salts in aqueous solution will appear in another place. UNIVERSITY COLLEGE, DUNDEE.

ISSN:0368-1645    

DOI:10.1039/CT9007700005

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

YREPARATIOK AND PROPERTIES OF SOLID AMMONIUM CYANATE:. 21 llI.-The Prxparation and Propevties of Solid Ammo&in~ Cyanate. By JAMES WALICER and JOHN K. WOOD. WHEN a solution of ammonium cyanate (prepared by the double decomposition of silver cyanate and ammonium chloride) is evaporated to dryness, either on a water-bath or in a vacuum at the ordinary22 WALKER AND WOOD : THE PREPARATION AND temperature, the residue is found t o consist entirely of urea, the transformation of the cyanate into urea taking place at an ever- increasing rate as the concentration of the solution becomes greater (Walker and Hambly, Trans., 1895, 67, 746). I n alcoholic and other solutions, the conversion of ammonium cyanate into urea is still more rapid (Walker and Kay, Trans., 1897, 71, 489), so that, in order t o obtain pure ammonium cyanate, it is necessary to prepare i t directly in the solid state.Liebig and Wijhler (Ann. Phys. Chem., 1830, 20, 393) attempted t o prepare it by direct union of ammonia and cyanic acid, both sustances being in the form of gases. They describe their experiments as follows : “When the vapour of the acid was passed into dry ammonia gas contained in a wide glass tube over mercury, the tube became warm and the gases condensed t o a cloud which soon settled on the inner wall of the vessel as a microcrystalline, very voluminous, woolly mass. I n order to obtain it in larger quantity and free from the impurity of mercury, we brought the gases into contact in a dry flask. The cloud which was formed with simultaneous heating of the flask was deposited as a loose, snow-white powder, and a t the mouth of the tube which delivered the cyanic acid gas there was produced a thick woolly vegetation, which, on account of the heat; evolved, soon melted t o clear drops which fell from the tube.” They showed that the loose powder gave the reactions of a cpnate, the clear drops being urea produced from the cyanate by the heat of the reaction.The powder, when left over mercury in presence of ammonia, remained unchanged for n week. Left in a vessel loosely covered with paper, it con- tinuously gave off ammonia, and in two days was almost entirely con- verted into urea. Both the freshly prepared cyanate and the urea formed by its transformation left a residue of much “insoluble cyanuric acid ” (cyamelide) when treated with water.“ From these facts it appears then that ammonium cyanate is a basic salt, which undergoes transformation in to urea with loss of ammonia.” It seemed t o us likely that if we could prevent the heat produced by the union of the ammonia and the cyanic acid vapour from raising the temperature to a point a t which ammonium cyanate was decom- posed or transformed, we might be able to obtain the normal cyanate in the pure state, and free from any admixture of urea or cyamelide. The method we a t first adopted was to mix ethereal solutions of the reacting substances a t the temperature of a good freezing mixture, and this we found t o be successful. A wide glass tube was bent at a n obtuse angle, and the horizontal portion charged with anhydrous cyanuric acid.The other limb passed downwards through a cork closing the mouth of a wide test- tube, and dipped beneath the surface of anhyclrous ether which thePROPERTIES OF SOLID AMMONIUM CYAN ATE. 23 test-tube contained. This ether was kept at a temperature not exceeding - 17O by means of a freezing mixture, The cyanuric acid in the horizontal limb was gradually heated with a Ramsay burner, a moderately rapid stream of hydrogen being at the same time passed through the tube in order to carry over the resulting cyanic acid vapour into the ether, in which the bulk of it dissolved. It is impossible to avoid the condensation of a considerable portion of the cyanic acid vapour t o form cyanuric acid or cyamelide, so that, unless the tube chosen is a t least half an inch in diameter, it is apt to become blocked before the experiment is completed. We now freed the ethereal solution of cyanic acid from cyamelide and other solid matters by filtration through a dry filter, and mixed it with a solution of ammonia in anhydrous ether in such proportions that the acid remained in slight excess.As a rule, the ethereal solution of ammonia was also cooled to the temperature of the freezing mixture, but experiments showed that this was not absolutely necessary. A flocculent, semi- gelatinous precipitate separated as soon as the solutions were mixed, and the temperature did not rise more than a few degrees, the heat of the reaction being mostly absorbed in warming the solvent. The precipitate was collected as rapidly as possible with the aid of a filter-pump, and freed from ether in an exhausted desic- cator over sulphuric acid.I n the case of some samples used for analysis, moisture was carefully excluded during the process of filtration, and the temperature was kept below zero by means of a freezing mixture surrounding the frlter-tube. When the ether had been entirely removed from the precipitate, the latter presented the appearance of a pure white mass, caked together and very friable. It dissolved completely in water, the solution having a perfectly neutral reaction to litmus, so that neither cyamelide nor free ammonia could be present. On the addition of strong nitric acid, there was a copious evolution of gas, and no precipitate of urea nitrate was obtained. Silver nitrate gave a pure white precipitate, soluble in nitric acid, and also in boiling water, from which crystals were deposited on cooling.These reactions all tended to show that the substance was ammonium cyanate free from admixture of the impurities met with by Liebig and Wohler, and analysis served to confirm this conclusion. 0.0607 gave 0,0441 CO, and 0.0382 H,O. 0.0351 C: = 19.8 ; H = 7.0. ,, 13.80 C.C. moist nitrogen at 11.5" and 760mm. N = 46.8. CH,ON, requires C = 20.0 ; H = 6.7 ; N = 46.7 per cent. The ammonia in the ammonium radicle of the substance was estimated by adding a weighed portion to excess of silver nitrate (whereby silver cyanate and ammonium nitrate were produced),24 WALKER AND WOOD : THE PREPARATION AND filtering, and distilling the filtrate with caustic soda, the ammonia evolved being collected in a known quantity of hydrochloric acid, and determined by titration in the ordinary way.0.1026 yielded ammonia which neutralised 17.08 C.C. of N/10 acid. NH,CNO requires NH, = 30.0 ; found 30.0 per cent. The amount of the cyanate radicle was estimated by adding a known weight of the substance to excess of decinormal silver nitrate, silver cyanate being precipitated. Although silver cyanate is perceptibly soluble in water, it is almost insoluble in water containing silver nitrate (Walker and Hambly, Zoc. cit., 747). The precipitate was there- fore washed in a Gooch crucible, first with water containing a little silver nitrate, and then with absolute alcohol until the filtrate gave no reaction for silver.The silver cyanate was then dried a t 120' and weighed. 0.1235 gave 0.3126 AgCNO. NH,CNO requires CNO = 70.0 per cent. These analyses show that the substance obtained by mixing ammonia and cyanic acid in ethereal solution at a low temperature is normal ammonium cyanate free from admixture with other substances, In order to ascertain if it were not possible to prepare pure ammonium cyanate without the medium of a liquid solvent, the gaseous sub- stances were brought together at the ordinary temperature in a diluted state, so that heating might be avoided as far as possible. A current of dry hydrogen was led through a cooled et.herea1 solution of cyanic acid, and then by means of a glass tube to the bottom of a large globe. Into the same globe was led a stream of air which had bubbled through strong aqueous ammonia, and had then been dried by passing over quicklime and solid caustic potash.These gases there- fore carried into the globe gaseous cyanic acid and ammonia re- spectively in a dilute condition. The currents mere so regulated that the reacting substances were delivered slowly, and as they entered at different parts of the large globe, the process of mixing was very gradual, the ammonium cyanate falling as a sort of snow at the bottom of the globe, and forming vegetative growths round the mouths of the delivery tubes. After a sufficient quantity had collected, the substance was a t once transferred to a desiccator, which was rendered vacuous in order t o remove any excess of ammonia or cyanic acid which might cling to the salt.The substance was found, as before, to dissolve in water without residue, and to yield a perfectly neutral solution. It there- fore contained neither cyamelide nor free ammonia,, and analysis showed that it was free from urea. CNO= 70.9.PROPEHTI ES OF SOLID AMMONIUM CYANATE. 25 0.1818 gave 0.4496 AgCNO. CNO = 69.3. 0.1823 ,, 0.451 7 AgCNO, CNO = 69.4. NH,CNO requires CNO = 70.0 per cent,. That the precipitdte obtained by the addition of the substance to the silver nitrate solution was in reality silver cyanate, was proved by converting the silver salt in the Gooch crucible directly into chloride by means of hydrochloric acid, and weighing the silver chloride thus produced. 0.4517 silver salt gave 0,4297 AgCl. Ag = 71.6. AgCNO requires Ag = 72.0 per cent.It thus appears that pure ammonium cyanate may be prepared by the union of gaseous ammonia and cyanic acid, if care be taken t h a t the heat produced by their combination does not raise the temperature of the product to the point a t which i t is transformed into urea. The solid cyanate, when prepared from the gases, presents under the microscope the aspect of very fine needles which show double refraction when examined witah a polarising apparatus. It is very readily soluble in water, and the solution, when evaporated, leaves a residue of urea. On heating in a capillary melting point tuhe, it contracts visibly a t a temperature somewhat above 60° and melts suddenly at a temperature in the neighbourhood of 80°, the exact point depending on the rate of heating and on the tightness with which the substance is packed in the tube. The fused mass, however, speedily resolidifies, and does not melt again until a temperature of 128--130° has been reached.The contraction a t 60' indicates incipient conversion into urea. A t 80°, the transformation takes place so rapidly that enough heat is evolved t o fuse the urea produced, the second melting point of 130' being that of urea. During the first fusion, a small quantity of gas is invariably evolved, and when the experiment was repeated on a larger scale the gas was found to be ammonia. It was noted also that although the original ammonium cyanate was completely soluble in water, the product after transformation left a slight insoluble residue which was apparently cyamelide. This production of small quantities of ammonia and cyamelide constantly accompanies the transformation of solid ammonium cyanate into urea, and sufficiently explains the origin of the impurities obtained by Liebig and Wohler, as well as their inference that the substance produced by the union of gaseous ammonia and cyanic acid is a basic ammonium cyanate.A quantitative experiment was made in order to determine the amount of ammocia given off during the conversion of the solid cyanate into urea. A Lunge nitrometer was filled with dry mercury up to the Greiner aad Priedricb stopcock with which it was provided.26 WALKER AND WOOD : THE PREPARATION AND There was then connected directly to the capillary tube, by means of a small piece of thick-walled rubber tubing, a bulb-tube which contained 1 gram of solid ammonium cyanate.By raising and lowering the mercury reservoir, with suitable manipulation of the stopcock, the bulb was rendered vacuous, and the mercury finally permitted to run back so as to fill it. The bulb was then heated in water at 95O, and after about a minute gas was vigorously evolved. When the trans- formation mas complete, the mercury levels were adjusted and the volume of gas read off, tho capacity of the bulb and capillary having previously been determined ; 1 C.C. of water was then introduced into the nitrometer, and in this the gas dissolved completely. The volume of ammonia obtained in this experiment and reduced to normal con- ditions was 11.4 c.c., corresponding to 0.0086 gram. The quantity of drj7 cyanate which mould produce this amount of ammonia is 0.030 gram, so that me may say that 3 per cent.of the cyanate on trans- formation is decomposed with production of ammonia, the rest of the molecule being probably converted into cyanuric acid and cyamelide. For purposes of comparison with the ammonium cyanate prepared i n aqueous solution by Walker and Hambly, a determination of the rate of transformation into urea mas made. A decinormal solution of the pure ammonium cyanate was prepared, and the progress of its con- version into urea followed by means of silver titration as previously described (Trans., 1895, 6'7, 746). The temperature of experiment was 50.2'. l a t A - x ' t. X. A -x. 55 4.94 17.96 0*00500 97 7.44 14.46 0.00496 186 10.74 12.16 0.00475 298 13.64 9.26 0.00494 -.- Mean ... ... ... ... 0.00491 1 x t ' A - x The mean value for the expression - - here observed is identical with that calculated for the same temperature from the formula used to express the results of all the experiments in aqueous solution (Walker and Hambly, Zoc. cit.). Thennochenzistry of Anzmonium Cycmate. From the displacement by change of temperature of the point of equilibrium between ammonium cyanate and urea in aqueous solution, Walker and Kay (Zoc. cit., p. 507) were able to calculate roughly the heat of transformation into urea of the cyanate in the form of ions,PROPERTIES OF SOLID AMMONIUM CYANATE. 27 They found that the heat of transformation was positive, and of the dimensions of 50 K per gram-molecule, R being equal to 100 cal.It was of interest, therefore, to determine directly, if possible, the heat of transformation of solid ammonium cyanate, and also its heat of solu- tion, for from these data and the known heat of solution of urea the heat of transformation of the dissolved cyanate can be calculated. The accurate determination of the heat of transformation of the solid cyanate into urea presents considerable difficulty, inasmuch as the conversion only takes place readily a t about 80°, and therefore necessitates somewhat complicated apparatus. Since, however, the actual transformation is always accompanied by secondary decompo- sitions, an accurate determination for the pure reaction is plainly impos- sible, so that we contented ourselves with experiments made by means of simple apparatus, which afforded numbers probably within 5 per cent., and certainly within 10 per cent., of the real value.The calorimeter consisted of' two beakers, one within the other, the inner one being supported on cork prisms, and kept from contact with the outer beaker by means of cardboard rings. These beakers were introduced into a double-walled steam oven and rested on a piece of asbestos, which was in turn supported by a stage made of glass tubing. Through the hole in the top of the oven were introduced a ther- mometer, a stirrer, and a wide glass tube for delivering the experi- mental substances, all three projecting into the inner vessel after passing through corresponding apertures in the cover of the outer beaker. The most suitable calorimetric liquid we found to be melted paraffin wax, about 50 grams of which were contained in the inner vessel.The thermometer employed was divided into tenths of a degree, so that hundredths of a degree could be estimated. To perform an experiment, the water in the walls of the steam oven was kept at a constant level and in steady ebullition until the temperature registered by the thermometer in the pa-raffin became constant, which it usually did in the neighbourhood of 96" after about 5 hours, A weighed quantity of mercury of known temperature was then rapidly introduced through the wide glass tube into the inner vessel, and the course of the thermometer was followed for about 10 minutes. From the readings, the weight, specific heat, and original temperature of the mercury, the amount of heat taken up by the latter could be easily calculated.Thus 60 grams of mercury at 14-70", when introduced into the beaker containing 49 grams of paraffin wax, lowered the temperature from 95.SO" to a minimum of 92.12'. The mercury had therefore absorbed 154 cal. from the calorimeter and had thereby lowered the temperature 3*6S0, or making due allowance for the rate of heating, 3*S6". A similar experiment28 WALKER AND WOOD: THE PREPARATION AND made with the same weight of paraffin showed that 152 cal. absorbed by the mercury lowered the temperature of the calorimeter 3.88". After preliminary experiments had shown the approximate value of the heat of transformation of ammonium cyanate, a quantity of this material was chosen so that, by its conversion into urea, it would give to the calorimeter about as much heat as the mercury had absorbed in the previous experiments, all other conditions remaining the same.The weighed quantity of cyanate was compressed into the form of a short cylinder in order that it might be easily introduced through the glass tube into the calorimetric vessel. After the cyanate had entered the paraffin, the thermometer at first fell, owing to the heat required to raise the temperature of the cyanate to the transformation point ; thereafter, the rise was rapid, a maximum temperature being soon reached. By making use of the previous experiments with mercury, the total amount of heat supplied to the calorimeter could be easily calculated, allowance being made for the rate of cooling from the thermometric observations.The heat of transformation was greater than this amount by the quantity of heat necessary to raise the temperature of the cyanate, or its transforma- tion products, from the atmospheric temperature to the maximum temperature observed. I n calculating this quantity, it was assumed that the cyanate had the same specific heat as its chief transformation product, urea. From the experiments, i t appears that the molecwlur h a t of tyansfownation of solid ammonium cyanate into solid urea is 49 K, the chief source of uncertainty lying in the unknown thermal change which accompanies the decomposition of 3 per cent, of the cyanate with formation of ammonia. Another set of experiments made with a modified apparatus in which a Victor Meyer toluene bath was used instead of a steam oveu, yielded a mean value of 48 K as the molecular heat of transformation of the cyanate. I f we accept 49 K as the heat of conversion of the cyanate into urea, it follows that the molecular heat of formation of solid ammonium cyanate from its elements is 738 K, since 787 K is the molecular heat of formation of solid urea, and this must be greater than that of the cyanate by the observed heat of transformation.I n determining the heat of solution of ammonium cyanate, the calorimeter chosen mas of the simple form described by Nernst (Zed. p?hysikaZ. Chem., 1888, 2, 23). The amount of water employed was 200 grams, the water equivalent of the calorimeter being 11.8 grams, as calculated from the weight of materials, and 11 grams as found by direct experiment.The substance whose heat of solution was to be investigated was enclosed in a thin-walled glass bulb weighted withPROPERTIES OF SOLID AMMONIUM CYANATE. 29 mercury so as to sink in the water of the calorimeter. When the temperature had become constant, the bulb was broken and the course of the thermometer observed. In order to test the apparatus, the heat of solution of urea was first determined. The values obtained were -36.1, - 36.6, and - 3 6 . 3 Kfor the gram-molecule, in good accordance with Rubner's number of For the rnokcula~ heat of solution of ammonium cyanate, the mean of two concordant experiments WiLS - 62.3 X, the strength of the resulting solution being about one-twentieth normal. This number is somewhat greater than me had anticipated, being in excess of the corresponding value for potassium cyanate, namely, -52 K, in opposition to the general rule that the potassium salts have greater heats of solution than the ammonium salts of l;he same acids.The divergence cannot be explained by the assumption that a portion of the cyanate is trans- formed into urea during the progress of the experiment. The portion so transformed could a t most have reachedonly 2 per cent. of the total, and the thermal effect of the transformation would have been to diminish the heat of solution instead of to increase it. The heat of transformation of the cyanate into urea in aqueous solu- tion may be calculated from the corresponding value for the solid sub- stance as follows.We may pass from solid ammonium cyanate to dissolved urea in two ways, namely, by transforming the cyanate in the solid state and then dissolving the urea, or by dissolving the cyanate and then transforming it in aqueous solution. The total heat effect must be the same in both cases, so that we obtain the equation : Heat of transformation of solid cyanate + heat of solution of Heat of solution of cyanate + heat of transformation in solution, -36.8 K. urea = or, substituting the numerical values for the gram molecular weight, whence x = 75 K. 4 9 K + ( - 3 6 Zi) = - 6 2 K + X, This value for the heat of transformation of the gram-molecule of ammonium cyanate in aqueous solution is considerably in excess of the value 50 K calculated from the displacement of the equilibrium point with change of temperature.This latter value, however, can only be taken as indicating the sign and dimensions of the heat change, since in the calculation it mas assumed that the transformation was pure, instead of being complicated, as is actually the case, with subsidiary actions which affect the accuracy of the deduction, and, secondly, that the cyanate was fully dissociated at the dilutions considered, an assumption which is only approximate. The number 75 K must there-30 WAT,KER AND WOOD : THE PREPARATION AND fore be accepted as a considerably closer approximation to the true value than the number 50 K, since it is affected by much smaller sources of error. It may be noted that the value observed for the heat of transforma- tion of the solid cyanate is sufficiently great to account for the fusion of the urea which occurs when the transformation takes place suddenly at about SOo.At this temperature, the transformation proceeds at such a rate that the heat evolved cannot all escape by conduction; the temperature therefore rises and the action is accelerated until it pro- ceeds almost instantaneously, with sudden evolution of so much heat that the temperature is raised above the melting point of urea, the heat of fusion of urea being probably less than - 25 K. Rute of Dansformation into Urea. It has been already stated that the substance obtained by Liebig and Wohler remained unchanged for a week in an atmosphere of dry ammonia, whilst in the course of two days it was almost entirely con- verted into urea when exposed t o the air, ammonia being continually evolved during the transformation.Liebig and Wohler were appar- ently of opinion that the presence or absence of ammonia was the determining circumstance in the conversion. This, however, is not the case, as we have found that moisture plays the chief part in determining the rate of transformation at moderate temperatures. Exposed to a moist atmosphere, the cyanate, as Liebig and Wohler observed, is converted into urea in the course of a few days. If left in a desiccator over sulphuric acid, the cyanate in the same length of time remains practically unchanged; and in an exhausted tube in presence of phosphoric oxide the cyanate shows little sign of altera- tion even after several months.Two tubes were prepared, one with dry (but not specially dried) cyanate, the other with the same material and a minute trace of moisture introduced from the end of a fine capillary. These tubes were sealed off and heated at the same temperature for the same length of time. I n the tube containing the added moisture, 27 per cent. of the cyanate had been transformed into urea, whilst in the other tube only 2 per cent. had undergone transformation. As might be expected, temperature has a great influence on the rate of transformation. It has already been indicated that the transforma- tion proceeds at a noticeable rate when the temperature reaches 60' for then a distinct diminution in volume is visible when the substance is contained in a, capillary tube. An experiment with ordinary dry cyanate showed that in the course of two hours 80 per cent.of the cyanate was converted into urea at that temperature.PROPERTIES OF SOLID AMMONIUM CYANATE. 31 I n order t o ascertain the effect of temperature on the rate of trans- formation of carefully dried cyanate, the following experiment was made. Four small tubes were charged with weighed quantities of cyanate and placed in tubes which were slightly wider than themselves and contained a layer of phosphoric oxide on the bottom. These outer tubes were then rendered vacuous and sealed off, After ten days, the tubes, without being opened, were heated at various temperatures, either in thermostats or in boiling liquids, for such lengths of time as preliminary experiments had shown would bring about approximately the same extent of transformation. The times required for the con- version of 3.5 per cent.of the cyanate into urea are exhibited in the following table : Temperature. Time in hours. 3 3" 50 40 19 45 7 57 1.1 The dried cyanate, like the freshly prepared material, passed rapidly into urea, with fusion when the temperature was raised to a little over 80". The rate of transformation we found to be by no means proportional t o the amount, of cyanate present, as the following figures indicate. The cyanate used was contained in vacuous tubes and dried for five days over phosphoric oxide in the manner desciibed above, the tem- perature of transformation being 57". Time in hours. Percentage traiisforined. 1 5.4 2 1914 5 58.6 10 95.1 I n the first hour, only 5-4 * per cent.was converted into urea, whilst in the second hour 14 per cent. of the original amount, or 14.7 per cent, of the amount remaining after the first hour, underwent transforma- tion. Between the second and fifth hours there was transformed hourly, on the average, 16 per cent. of the amount of cyanate which remained at the beginning of the time, and in the last period of five hours there was an hourly average transformation of 18 per cent. of the amount of cyanate present at the commencement of the period. There are thus evidences of a gradual acceleration of the action as it progresses. This we might expect, since the transformation is one in a condensed two-phase system. The action is probably not uniform * This number is greater than the corresponding number in the temperature experiments quoted above, on account of less perfect drying.32 PREPARATION AND PROPERTIES O F SOLID AMMONIUM CYANATE, through the whole mass, but proceeds from definite points or nuclei, the rate increasing as the surface of contact between the two phases increases, as it does in the crystallisation of an over-cooled liquid, or the conversion of one crystalline modification into another.So far as we have observed, there is no tendency to the reverse transformation of urea into ammonium cyanate in the solid state. After being heated for a long time in a vacuous tube at l l O o , dry urea was found to be unchanged, dissolving completely in water with forma- tion of a perfectly neutral solution which gave no precipitate with silver nitrate.After heating for 6 hours at 129', that is, just below its melting point, i t was found to have slightly decomposed with pro- duction of ammonia, but the presence of cyanate could not be proved in the residue. Whether the ammonia and cyanuric acid produced by heating urea to a still higher temperature are entirely the decomposition products of urea and biuret, or are in part derived from ammonium cyanate into which a portion of the urea may have been transformed, is a point to which we can at present give no definite answer. Waddell (J. Physical Chem., 1898, 2, 525) has shown that solid ammonium thiocyanate does not suffer transformation into thiourea below a temperature of 110'. When fused, however, at temperatures of 150' and over, it is gradually converted into thiourea, the rate of transformation rising rapidly with the temperature.I n this case, the transformation is not complete, equilibrium being attained when the fused mass contains 80 per cent. of thiourea and 20 per cent. of thio- cyanate. The existence of a similar state of equilibrium between urea and ammonium cyanate cannot be ascertained, owing to the decom- position which these substances suffer when in the fused state. There can of course be no such equilibrium between the solids, for when two mutually convertible solids are in contact with each other, there is no real equilibrium between them except a t one definite temperature, the transition or inversion point, a t which temperature they may be brought together in any proportion without either undergoing change.I n the fused state, on the other hand, the substances are miscible, and thus form but one phase instead of two, the system thereby gaining an additional degree of freedom, so that equilibrium may be attained at any temperature, the composition of the system changing according as the temperature varies. What the transition point of ammonium cyanate and urea may be, we are not in a position to determine. All that can be said is that it is above 80', and in all probability very far above that temperature.DAVIS : ETHERIFICATION OF DERIVATIVES OF ,B-NAPHTHQL. 33 Substituted Ammonium Cyanates. When dry ethylamine was gradually mixed with the vapour of cyanic acid, the two substances united to form a light, colourless powder, the solution of which, in water, gave a precipitate of silver cyanate when brought into contact with silver nitrate solution. The white powder, therefore, consisted, in part, a t least, of ethylammonium cyanate. On standing for some time, it showed indications of lessening in bulk, and eventually it liquefied. The liquid, however, soon set to a solid mass, which, when dissolved in water, gave no precipitate with silver nitrate. The phenomena encountered here are consequently similar to those met with in the case of ammonium cyanate, the only difference being that the ethylammonium cyanate is rapidly converted into ethyluren at a much lower temperature than suffices €or the rapid transformation of ammonium cyanate. An ethereal solution of aniline, when mixed with an ethereal solu- tion of cyanic acid, gave no immediate precipitate, but the solution deposited a crystalline substance on standing for Mome time. The crystals which separated, however, did not behave as phenylammonium cyanate, but as phenylurea. A similar result was obtained with p-toluidine as base ; the crystalline substance which separated from ths ethereal solution on standing proved to be p-tolylurea, and not ptolplammonium cyanate, These substituted ammonium cyanates therefore pass much more readily into the corresponding ureas than ammonium cyanate itself. UNIVERSITY COLLEGE, DUNDEE.

ISSN:0368-1645    

DOI:10.1039/CT9007700021

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

DAVIS : ETHERIFICATION OF DERIVATIVES OF ,B-NAPHTHQL. 33 IV.-Etherification of Derivatives of ,&Naphthol. By WILLIAM A. DAVIS. IN the following pages, an account is given of the etherification of derivatives of P-naphthol by heating the naphthol with a mixture of alcohol and sulphuric acid (Henriques, compare Gattermann, Annalen, 1887,244, 72). It is shown that, whereas @naphthol yields an almost theoretical amount of ether, most of its derivatives can only be very partially etherified. As no action occurs at the ordinary temperature, in the first series of experiments a mixture of 2 grams of purified naphthol with 2 grams of the alcohol and 0.8 gram of sulphuric monohydrate was gently boiled during 6& hours on the sand-bath in a test-tube attached to a condenser. VOL.LXXVII. D34 DAVIS : ETHERIFCCdTLON OF DERIVATIVES OF B-NAPHTHOL. To free the ether from unchanged naphthol, an excess of dilute caustic soda was then added, and the mixture gently warmed, a preliminary experiment having shown that this could be done without hydrolysis or dissolution of the ether taking place. The ether was collected on a tared filter-paper, which had previously been exposed in a weighing bottle in a vacuum until its weight was constant, and after being thoroughly washed, was dried in a vacuum desiccator and weighed. The results obtained are given in Table I. Owing t o a considerable proportion of the alcohol being converted into ethyl ether by the action of the sulphuric acid at the temperature at which the mixture boiled, it was generally observed that the latter separated, after about 3 hours, into two layers, of which the upper contained the alcohol and sulphuric acid, whilst the lower consisted of the naphthyl ether and unchanged.naphthol. Owing to this separation, little etherification occurred after the third hour. It was found, how- ever, that at loo", whilst the formation of ethyl ether was largely pre- vented, that of the naphthyl ether was not interfered with ; in addition, the disturbing influence which is undoubtedly exercised on the etheri- fication by varying the rate of ebullition was entirely excluded. Table I1 gives the results obtained at 100'. In these experiments, the mixture was heated during a much longer period than in the experi- ments recorded in Table I, and a definite limit of etherification was attained ; it is doubtful whether this limit had been reached in the first series of experiments, as will appear on comparing the two sets of results.The method of heating a t first adopted was to surround the tube containing the etherification mixture with boiling water, but the results obtained were, in some cases, vitiated by moisture permeating the cork; subsequently the lower portion only of the tube was heated by passing it through a cork fitted into the neck of a steam-bath con- structed from a sheet-iron can by soldering six short tubes 1 inch in diameter round the central neck. A condenser, fitted to the central neck, served to keep the volume of water in the can practically constant. Table I11 gives the results of experiments carried out a t looo, using methyl instead of ethyl alcohol; these values are probably not quite so trustworthy as those of Table 11, for two reasons.First, the mix- ture used boiled below loo", and a considerable decrease in its amount occurred owing to the formation of methyl ether; secondly, a small proportion of the naphthyl ether sublimed, and thus a change in the condition of equilibrium was introduced. The latter circumstance probably accounts for the fact that the amounts of ether obtained with methyl are higher than those obtained with ethyl alcohol ; in experi- ment 2, especially, much sublimation occurred. The results obtained with 3-bromo-%naphthol are possibly slightly higher than the trueDAVIS : ETHERIFICATION OF DERlVATIVES OF @-NAPHTHOL.35 B-Naphthol....... ................. , , . . . . . . . . . . . , . . . . . . . . , . . . . 3'-Bromo-2-naphthol . . . . . . . . . . . . l-Bromo-2-naphthol . . , . . . . . . . . . 9 9 ,) ..... * ...... values, owing to the fact that 3'-bromo-2-methoxynaphthalene does not melt below 100' when warmed with dilute caustic soda, so that small quantities of unchanged naphthol probably remained occluded ; more- over, much of the product sublimed. The alcohol used boiled at 66*0-66*5O under 759 mm. pressure. Similar experiments were made with propyl alcohol (b. p. 96-25-97' under 74'7.5 mm. pressure) ; the results are given in Table IV. I n the case of 1 : 3'-dibromo-2-naphthol, resinous substances insoluble in caustic soda were formed owing to the occurrence of secondary change.6 64 6* 64 62 TABLE I.-EthwiJication at the boiling point. No. ?f experi- ment. 1 2 3 4k 5 6 7 8 9 10" 11 12 13" 1 4 15 16 17 18 19 20 21t 2 2 t 23 24 25 26" 27 28" 29 30 Naphthol. Time in hours. 9 , 7 , Y9 Y , >> 7 ) a . . . . . . . . . . . ) ) ... ... ..... , , ,, ...... . ..... ,) ...... * ..... . . . . . . . . . . . . 1 - Chloro-2-naphthol . . . . , . . . . . . . l-Iodo-2-naphthol . . , . . . . . . . . . . . . 1 : 3'-Dibrorno-2-naphthol. .. , . . 9 , 7 , ............ 9 , Y ) ,? $ 9 9 , ,, , l 9 ) 7 ) .... ... ..... , , ,) ...... I ..... ,) ............ ,, .... * ....... ,, ....... ..... ,) ............ 7 7 ... ......... . . . . . . . . . . . . 1 -ChIoro-3'-bromo-2-naphthol. Y 9 9 7 # ) * 7 ) 9 , ), * 62 1 : 3~Dichloro%-naphthl .... ..:I 64 9 3 .. . . . . . 9 , Tribromo-2-naphthol (m. p. 155") .. .... .. . ... .. . . . . ..:. .. ... 1 -Ni tro12-naphthol. . , . . . . . . , , . . . . I 61 Percentagl yield of ether. 83 .O 84.1 68-0 69.7 9 -7 20'2 23 -1 2'1 4 '1 5.0 8 *1 10.0 9'4 7'6 9.7 1'4 1 -25 0 *7 3 '4 0'0 0.0 3 -9 2.3 0.9 1 '5 0'0 0.0 0.0 0 '87 1' Map. of product weighed. 36" 37 77-78 76-77 54-56 55-58 64-65 62-64 6 4-6 5 55-56 55-56 in form 74-76 79-80 79 89 89-90 88 65-70 54-58 - - 65-67 75 74 74 - - - 96-98 M.p. of pure ether. 37.50 37-5 80 80 66 66 66 66 66 66 58 58 94 94 94 94 94 94 94 77 77 77 77 d. - - - - - 104 In all experiments except those marked * and t, the proportions in grams mere-naphthol : ethyl alcohol : sulphuric acid = 2 : 2 : 0-8 ; in those marked with an asterisk, the moZeculas* proportions mere the same as in the etherification of /3-naphthol, namely, 1 mol.naphthol : 3-12 mols. alcohol: 0.59 mol. acid. I n two experiments, Nos. 21 and 23, 0 236 DAVlS : ETHEHIFIC'ATLON OF DEHLVATIVES OF @-NAPHTHOL. the proportion of sulphuric acid was the same as in the experiments with /3-naphthol, but 2 grams of alcohol were used. Unsatisfactory results were obtained in experiments 5,6,7, 14,15,and 16 with l-bromo- and 1 : 3'-dibromo-%-naphthol, owing to the fact that the mixture was boiled too rapidly, this giving rise to compounds insoluble in dilute caustic soda, which seriously interfered with the purity of the ether. Moreover, on filtering the dilute, alkaline solution of the unchanged naphthol, oxidation apparently occurred, and the solution became purple in colour, depositing a finely-divided purple or brownish powder in the pores of the filter paper, thus preventing further filtration.I n the later experiments (Nos. 8, 9, 10, 17, 18, 19), the ebullition was careful regulated and the filtration hastened by using a filter-pump ; under these conditions, the ether weighed was nearly pure. The melt- ing points given in the table serve to indicate the degree of purity of the products weighed. TABLE 11. --EtheriJimtion at 1 OOO. Proportion8 :-Naphthol : ethyl alcohol : sulphuric acid = 2 : 2 : 0.8 grams. No. of experi- ment. 1 2 3 4 5 6 7" 8 9 10' 11* 12 13 14* 15* 16 17 18 19 20 21 22 Naphthol. B- Naph thol ........................ I , ........................ Y ? ........................ I > Y 9 ................................................ 3'-Bromo-2-naphthol ........... 1 -Bromo-2-naphthol ............ Y ) ,, ........... ,, .......... l.C~loro-2-naphthol ........... ) ? JY 9 , ,, ........... ,) ........... 3, .......... 1 : 3'-Dibromo-2-naphthol. .... 1 -Chloro-3'-bromo -2-naphthol , I Y , ), ........... , , .......... , Y 2 9 , I * 1 : 3-Dichloro-2-naphthol ..... 1 . Nitro-2 -naph thol .............. l-Nitro-3-chloro-2-naphthoI . . 1 : 3 : 4-Trichloro~2-naphthol.. - Tjmc hours 111 24 3 t 11 2 20 15 20 6 t 6 i 159 20 25 11 20 16 20 20 20 20 164 64 - ~ Percentage yield of ether. 73'6 83'9 90.5 91'2 S9'1 88.7 3 '2 15'2 17.0 0-5 2 '1 9*3 8 '4 0.36 1*3 6.0 0.0 1.9 0.0 0.0 0 ' 0 0.0 M.p. of product weighed. 37-38" 37 ,, ?, ?9 62-64 62-64 63-64 55-56 55-56 56 56 - 82-85 84-86 67-76 - - - ...- M.p. of pure ether. 37'5" 37.5 9 , 9 , ? ¶ 80 66 66 66 58 3 ) ? ) Y , 94 9 3 ii 77 104 - - - I n the experiments marked *, the mixture was heated in boiling water ; in all others, the steam-bath was used.DAVIS : E'L'H 1CRIFICA'l'ION OF' DERIVATIVES OF B-NAPHTHOL. 37 TABLE 111.--Methylation at IOOO. I'y*oportions : Napht,hol : methyl alcohol : siilpliiit-ic acid = 2 0 : 2.0 : 0.8 grams. No. of experi- ment. 1 2 3 4 5 6 7 8 9 10 11 Naphthol. B-Naphthol.. ....................... ,, ......................... ,, ......................... 1-Rromo-2-naphthol ............ 3'-Broino-2-naphthol ............ Y 9 ,, ............ 9 9 ,, ............ 1-Chloro-2-naphthol ........... 1-Nitro-2-uaphthol .............. 1 : 3'-Dibroino-2-naphthol ......1 : 3'-Chlorobromo-2-naphtl1ol - Time in hours. 20 20 20 20 20 182 20 9 9 9 , $ 9 9 9 - Percen t a g yield of ether. 91 *15 95'9 91.3 21 *2 22 '4 98 -7 9 i -1 7 -45 5-4 0.0 0.0 M.p. of product weighed. 71-72" 7 1 71-72 80 104 104 60 73-76 80-81 - - M.p. of pure ether. 72' 72 72 82-83 82-83 105 105 68 100 126 - TABLE IV.--Propglation at looo. Proportions :-Naphthol : propyl alcohol : sulphuric acid = 2 : 2 : 0.8 grams. No. of experi- men t. 1 2 3 4 5 6 7 8 9 10 11 12 13 Naphthol. Time in hours. I- &Naphthol, ....................... 3'-Bromo-2-naphthol ............ 1-Bromo-2-naphthol .......... , , ......................... 9 , , , ........... 9 9 ,, ............ 1-Chloro-2-naphthol ............ I , ,, ............I 1 : 3'-Dibromo-2-naphthol.. ....7 ) ,, ............ l-Chloro-3'-bromo-2-naphthol. 1 : 3-Dichloro-2-naphthol.. ..... l-Nitr0-2-naphthol.~. ............ 12 20 20 20 20 20 20 20 16 20 20 20 20 Percentag yield of ether. 94 -5 93 *3 93 -8 92'0 12-7 12'9 0.75 0 *o 2.8 0.58 0'0 0 '0 de M.p. of product weighed. 38" 37-38 62 62 29 25-28 oil 45", dirty ompositj 56 - - - M.p. of pure ether. 39.5" 39.5 63.5 63-5 35-36 9 9 - - 75 60.5 n - - P-N'phtAyE Methyl Ethers. 3'-Bromo-2-methoxynaphthaZene, C,,H6Br*OMe, prepared by heating R mixture of 5 grams of 3'-bromo-2-naphthol (Armstrong and Davi?, Proc., 1896, 12, 231) and 5 grams of methyl alcohol during 10 hours at looo, is sparingly soluble in alcohol, moderately so in benzene, ethyl38 DAVIS : ETHERIFICATION OF DERIVATIVES OF ,&NAPHTHOL.acetate, chloroform, or acetone, and crystallises from acetic acid in balls of small, white needles; it melts at 105". 0.2342 gave 0.1875 AgBr. C,,H,OBr requires Br = 33.74 per cent. 1 -Bromo-2-methoxynup?~t?~a~ene, CIoH6Br* OMe, was prepared by heating 4 grams of 1-bromo-2-naphthol with 2.7 grams of methyl iodide, 1.4 grams of potassium hydroxide, and 10 grams of methyl alcohol during 5 hours in a sealed tube at 100'; it crystallises best from light petroleum, forms t h h , lustrous plates, and melts at 82.5'. Br = 34.07. 0,1643 gave 0.1290 AgBr. Br = 33.42. CllH,OBr requires Br = 33.74 per cent. 1 -ChZoro-2-rnethoxynap7~thaZene, C,,H6C1* OMe, prepared in a similar manner, crystallises from alcohol in thin, colourless plates, and melts a t 68'. 0.2100 gave 0.1571 AgC1.C1= 18-50. C,,H90Cl requires Cl = 18.41 per cent. 1 : 3'-Dibron~o-2-snethoxynaphthalene,CloH,Br,~OMe.-When 5 grams of I : 3'-dibromo-2-naphthol are heated with 2.5 grams of methyl iodide, 1.4 grams of potassium hydroxide and 12 grams of methyl alcohol in a s6aled tube during 6 hours at loo', a portion of the naphthol is not acted on, and only about 50 per cent. of the theoretical quantity of 1 : 3'-dibromo- 2-methoxynaphthalene is obtained ; it crystallises best from alcohol in small, nearly colourless plates and melts at 1009 0,1316 gave 0,1552 AgBr. C,,H,OBr, requires Br = 50.62 per cent. 1-ChZoro-3'- bromo-2-methoxynnp?~thaZene, CloH,CIBr*OMe, prepared in a similar manner from 1 -chloro-3'-bromo-2-naphthol, crystallises from hot alcohol in thin, colourless plates, which are at first transparent, but become slightly opaque as the solution cools, possibly owing to a change in crystalline form ; i t melts at 92.5'.Br = 50.20. 0.1428 gave 0.1747 AgCl + AgBr. AgCl + AgBr = 122.33. Cl1H,OC1Br requires AgCl + AgBr = 3 22.00 per cent. P-NaphthyZ Ethyl Ethers. l-Bromo-2-ethoxyn~pht~~a~n~,CloH,Br.OEt, is best prepared by adding bromine (1 mol.) drop by drop t o a solution of P-ethoxynaphthalene in glacial acetic acid, but is also formed by ethylating 1-bromo-2-naphthol; it crystallises from light petroleum in colourless plates and melts at 66".DAVIS : ETHERIFICATION OF DERIVATIVES OF @-NAPHTHOL. 39 3‘-Bro,,io-2-etho~L.ytici2,?~thuZeiie, C,,H,Br*OEt, is best prepared by heating n mixture of 5 grams of 3’-bromo-2-naphthol, 5 grams of ethyl alcohol, and 2.0 grams of sulphuric monohydrate during 6 hours at 100’ ; i t crystallises from alcoliol in colourless plates, melts at SOo, and is easily soluble in benzene, acetic acid, chloroform, ether, ethyl acetate, or light petroleum. 0.1382 gave 0.1041 AgBr.C,,H,,OBr requires Br = 31.88 per cent. On one occasion, a mixture of 20 grams of 3’-bromo-2-naphthol with 20 grams of ethyl alcohol and 8 grams of sulphuric acid was, by an oversight, boiled more vigorously than was intended, and nearly the whole of the alcohol evaporated; as a consequence a considerable quantity of 3’-bromo-2-naphtholdisulphonic acid (Arm strong and Davis, Proc., 1896, 12, 231) mas formed. On removing this by adding water, a small quantity of a heavy oil remained undissolved; on washing this with a little alcohol, it solidified to a dark, greyish powder.Ths alcoholic washings were poured into water and the precipitate obtained crystallised from light petroleum containing a small quantity of benzene, when small, colourless needles separated melting a t 125” ; these were insoluble in aqueous caustic soda and therefore did not consist of unchanged 3’-bromo-Z-naphthol, which melts a t 12’i0, but the quantity of substance obtained was insufficient to determine its nature by an analysis. The greyish powder left undissolved by the alcohol was crystallised from glacial acetic acid ; it separated in colourless plates melting a t 169’ to a deep red liquid ; after crystallisation, it became very sparingly soluble in glacial acetic acid and was insoluble in aqueous caustic soda.On analysis, the following numbers were obtained : Br = 32.05. 0.2140 gave 0.1813 AgBr. 0.2768 ,, 0.2327 AgBr. Br=35.79 ,, Br = 36-06 per cent. These results and the properties of the substance suggested that it was somewhat impure di-3’-bromo-2-naphthyl ether, ( CloH6Br),0. The quantity of substance obtained, however, was so small as to pre- clude further purification, but the view as t o its nature was con- firmed by a comparison with the dinaphthyl ether, Di-3‘-bromo- 2-nczphthyl etheris prepared by boiling 2 grams of 3’-bromo- 2-naphthol with 30 grams of 50 per cent. sulphuric acid during 12 hours in a reflux apparatus; the yield in these circumstances is small, most of the naphthol being recovered unchanged ; it crystallises from glacial acetic acid in colourless plates and melts at 170-171’, the melting point being unchanged by mixing it with the substance melting a t 169” which was believed to be identical with it,40 DAVIS : ETHEKIFICATION OF DERIVATIVES OF P-NAPHTHO L.0.0954 gave 0.0824 AgBr. C,,H120,Br2 requires Br = 37.22 per cent. l-ChZoro-2-ethoxynapl~t?~at?ene, CloH,C1*OEt, prepared by heating 1-chloro-2-naphthol (2 grams) with ethyl bromide (1.3 grams), caustic potash (1.0 gram), and absolute alcohol (12 grams) during 3 hours a t 1 OO", crystallises from alcohol in beautiful, colourless leaflets and melts at 58'; it is easily soluble in benzene or light petroleum, and very soluble in chloroform, ethyl acetate, or acetone. Br = 36.86. 0-2051 gave 0.1414 AgCl.C,,H,,OCl requires C1= 17.17 per cent. 1 : 3' : Dibromo-2-ethoxynaphthalene, CloH,Br2*OEt, is best prepared by gradually adding bromine (2 mols.) to @-cthoxynaphthalene dis- solved in four times its weight of glacial acetic acid, and subsequently warming a t 100'; it crystallises from light petroleum in beautiful, lustrous needles and melts at 94'. Its structure follows from its being formed when 1 : 3'-dibromo-2-naphthol is heated with the theoretical quantity of ethyl bromide and caustic potash in absolute alcohol during 5 hours at 100'. C1= 17.04. 0.1540 gave 0.1756 AgBr. C12HloOBr2 requires Br = 48.49 per cent. 1 -Chloro-S'- brorno-2-ethoxyaapl~thaZene, Cl,H,C1 Br OE t, obtained by heating l-chloro-3'-bromo-2-naphthol with ethyl bromide (2.5 grams), sodium hydroxide (1 gram), and absolute alcohol (15 grams) in a sealed tube for 6 hours at loo', crystallises from alcohol or light petroleum in thin, colourless, lustrous, elongated plates and melts at 77.5'; it is very soluble in benzene, chloroform, ether, acetone, or ethyl acetate.Br = 48.52. 0.1 829 gave 0.21 30 AgCl + AgBr. AgCl + AgBr = 1 16.5. C,,H,oOCIBr requires AgCl + AgBr = 116.1 per cent. P-Naphthyl Prop$ Ethers. @-Propoxynaphthalene, according to Bodroux (Compt. Tend., 1898, 126, 840), is formed on heating @-naphthol with propyl iodide and alcoholic potash, but it is best prepared by gently boiling a mixture of P-naphthol (10 grams), propyl alcohol (10 grams), and sulphuric monohydrate (4 grams) during 6 hours. It crystallises best from alcohol in long, colonrless needles, and melts at 39%' as stated by Bodroux. 3'-Bromo-2-propoxynaphthalene, CloH6Br*OPra, prepared in the same manner as P-propoxynaphthalene, crystallises from hot iLlcoho1 in beautiful, thin, transparent plates ; before crystallisation is corn-DAVIS : EC'HERIFICATION OF DEltIVnTlV ES OF B-NAPHTHOL.41 plete, nowever, white, opaqne balls of needles form, whilst these alone are obtained if the ,?mount of alcohol used has been sufficient to prevent crystallisation commencing until the solution has cooled to the atmospheric temperature. The transparent crystals apparentIy contain alcohol of crystallisation, but this is lost so mpiclly on exposure to the air that its amount could not satisfactorily be deter- mined ; when the plates are exposed to the air for 6 days, they crumble to powder, and are then free from alcohol, as the following analysis indicates : 0.2051 gave 011456 AgBr.Br = 30°21. C,,H,,OBr requires Br = 30.18 per cent. The pure snbstance melts at 6305'~ but after solidification melts quite sharply at 56' (three determinations), although after 36 hours the melting point has again risen to 63.5'; i t crystallises from glacial acetic acid or light petroleum in small, globular aggregates of whit'e ceedles and is very soluble in chloroform and ether. 1-B.r~omo-2-popoxync~phtl~alelze, CloH,Br*OPra, is best obtained by adding bromine (1 mol.), dissolved in an equal quantity of glacial scet,ic acid, drop by drop to a cooled solution of @-propoxynaphthalene in glacial acetic acid ; an oil separates which is washed with water and caused to solidify by surrounding it with ice; on crystallising from alcohol, nearly colourless, small, prismatic flakes are obtained melting a t 35-36'.It is also formed on heating 1-bromo-2-naphthol with propyl bromide (6 grams), ca.ustic potash (2.3 grams), and propyl alcohol during 5 hours a t loo', but the yield is poor (compare 1 : 3'-dibromo-2-propoxynaphthalene). 0-2032 gave 0.1428 AgBr. Br = 29.85. C,,H,,OBr requires Br = 30.18 per cent. 1 : 3'-Dibvomo- 2-propoxynupht?Lalene, CI,H,Br,*OPr", is best obtained by gradually adding 2 mols of bromine to /I-propoxynaphthalene dissolved in glacial acetic acid; it crystallises from alcohol in well-defined, slightly yellow prisms and melts a t 78". When 1 : 3'-dibromo- 2-naphthol (7.5 grams) is heated with propyl bromide (3.0 grams), caustic potash (2*3grams), and propyl alcohol (20 grams) in a sealed tube during 7 hours at 100°,a considerable proportion of the naphthol is not acted on, a portion is decomposed, giving rise to resinous products, and the yield of ether is small.0.1032 gave 0.1134 AgBr. C,,H,,0Br2 requires Br = 46.50 per cent. l-Chlo~*o-3'-bromo-2-popoxynaphthal~ne, C,,,H5CIBr*OPr,, obtained from l-chloro-3'-bromo-2-naphthol by the propyl bromide method, Br = 46.77.42 DSVIS : EFHlCRlF[rlATI9N OF DERIVATIVES OF @-NAPHTHOL. cryst;illises from alcohol, in which i t is moderately soluble, in large, nearly colourless, very thin plates, and melts a t 60.5.’ ; on analysis : 0.1848 gave 0.2050 AgCl + AgBr. AgCl + AgBr = 110.9.C,,H,,OClBr requires AgCl + AgBr = 110.6 per cent. BiscussioI~ of Iiesults. The results tabulated on pages 35-37 serve to show that a single halogen atom in position 1, contiguous to the hydroxyl group of @naphthol, has a most remarkable effect in limiting etherification, the effect being least in the case of methyl and greatest in that of propyl alcohol. Chlorine has an even greater effect than bromine, and n nitro-group in position 1 entirely prevents etherification. That the position of the halogen is the main determining cause of its influence is clearly brotight out by the fact that 3’-bromo-F-naphthol is etherified as easily as the unbrominated naphthol, but it will be seen that, on introducing bromine into position 3’ in either l-chloro- or l-bromo-@naphthol, the production of ether is considerably diminished.These results stand in striking contrast to those obtained in the well-known experiments made by Victor Meyer and Sudborough, since extended by others,” on the etherification of substituted benzoic acids. I n the case of benzoic acid, a single group in the ortho- position has little influence, whereas two such groupp, iF they do not altogether prevent etherification (01, Br, I, NO,), greatly affect either the rate a t which it takes place or its extent (CH,, OH, F). Victor Meyer has sought to find an explanation of these facts in stereo- chemical considerations, and has regarded the influence exercised by various radicles as dependent on their volume; but, strange to say, he has taken mass as the measure of volume.? Such a hypothesis appears to be by no means justified by facts.Thus the order of inhibitive influence of different radicles on the formation of ethereal salts of ortho-substituted benzoic acids appears from Kellas’ results to be C1, CH,, Br, I, NO,; but the order of the relative weights is CH,, C1, NO,, Br, I, and that of atomic volumes, CH,, 01, Br, NO,, I (Graham-Otto, I, 3, 449), or according to Traube (Alzncclelz, 1896, 290, 43) C l = B r = I (13~2)~ OH, (19.2), NO, (20). From Goldschmidt’s values for the velocity coeflicients, the radicles * V. Meyer and Sudborough, Ber., 1891, 27, 510, 1580, 3146 ; Lepsius, ibid., 1635 ; V. Meyer, Ber., 1895, 28,182, 1254, 2773, 3197 ; 1896, 29, 830, 1397 ; van Loon and V. Meyer, ibid. , 839 ; Golduchmidt, Ber., 1895, 28, 3218, Kellas, Zeit. plzysi- kal.Chem., l897,24, 221 ; Wegscheider, Monatsh., 1895,16, 75 ; Ber., 1895,28, 1474, 2535 ; Monatsh., 1897, 18, 629 ; Sudborough and Feilmann, Proc., 1897, 13, 241. For a discussion of this point, see V. Meyer, Ber., 1895, 28, 126 ; 1896, 29, 843 ; Wegscheider, Ber., 1895, 28, 126, Monatslb., 1897, 18, 635.DAVIS : ETH ERIFICATION OF DERIVATIVES OF &NAPHTHOL. 43 should stand, as regards retarding influence, in the order Br, C‘H,, NO,, but in the case of the naphthyl ethers, the order appears from my results to be Br, C1, NO,. So that the observations of Goldschmidt and of Kellas, as well as my own, are in accord neither with the arrange- ment by atomic weights nor with that by atomic volumes ; consequently, there appears to be a factor governing the etherification of both carboxylic acids and phenols * of which we are a t present in ignorance.Even if we consider, as Mudborough and Feilmann have suggested that the etherification is determined by two factors, (1) the stereochemical influence of the configuration, (ii) the strength of the acid as measured by its affinity constant, we are brought no nearer to an explanation of the extraordinarily great inhibiting influence of a nitro-group compared with that of other groups.? Wegscheider (Monntsh., 1895, 16, 75, and 1897, 18, 629) has given reasons for considering that, in the etherification of carboxylic acids under the influence of alcohol and concentrated sulphuric acid or hydrogen chloride, an intermediate compound is formed by addition t o the carboxyl group, as was originally assumed by Henry (Ber., 1877, 10, 204l), and later work has strengthened this hypothesis (compare Lloyd and Sudborough, Trans., 1899, 75, 580); he has suggested that phenols undergo etherification in a somewhat similar * Sudborough and Lloyd (Trans., 1899, 75, 467, 580) give a bibIiographyof papers dealing with the influence of ortho-substituted groups on the etherificatioii of acids, the hydrolysis of ethereal salts, and of acid chlorides, amides, and nitriles ; the results obtained by Kdster and Stallberg (AnnitZen, 1894, 278, 207) belong t o the same category.Contiguous groups also exert au important influence on the preparation of oxiines and phenylhydrazones of aromatic aldehydes and ketones (Kehrmann, Ber., 1888, 21, 3315 : 1694, 27, 3344 ; J.pr. C l ~ m . , 1890, [ii], 40, 257 ; Hantzsch, Ber., 1890, 23, 2769 ; Feith and Davies, Ber., 1891, 24, 3546 ; Petrenko-Kritschenko, Ber., 1895, 28, 3203 ; Bauin, Ber., 1895, 28, 3207, V. Meyer, Ber., 1896, 29, 830) ; the formation of imido-ethers from nitriles (Pinner, Ber., 1890, 23, 2917) ; and many other more complex interactions (compare Busch, J. yr. Chm., 1895, [ ii], 51, 113 ; 52, 273; 1896, 53, 414 ; lS97,55, 356; Jacobson, Annctlen, 1895, 287, 118 ; 1898, 303, 290 ; Ber., 1898, 31, 890 ; Anschutz, Rer., 1897, 30, 221 ; Bischoff, Ber., 1897, 30, 2478, 2772 ; 1898, 31, 3324 ; Scholtz, Ber., 1898, 31, 414 and 627 ; 1899, 32, 2261 ; Wedekiiid, Ber., 1898, 31, 1746 ; Friedlander, Monatsh., 1898, 19: 627 ; Paal and Schilling, J.pr. Chem., 1896, [ii], 54, 277 ; Paal and Benker, Ber., 1899, 32, 1251 ; Paal and Hartel, ibid., 2057). The presence of ortho-alkyl groups in aromatic ketones and ketonic acids also determines very largely the behaviour of these compounds on hydrolysis (Louie, Ann. Chirn. Phys., [vi], 1885, 6, 206 ; Elbs, J. pr. ChenL., [ ii], 1887, 35, 465 ; V. Meyer, Ber., 1895, 28, 1270 ; Muhr, ibid., 3215, and Weiler, Ber., 1899, 32, 1908). Victor Meyer, in discussing the atomic volume value, suggests “dass das Estergesetz uns ein Mittel in die Hand gebe die relative Raumerfullung der Atoine in den organischen Verbiiidungen mit einaiider zu vergleichen.” The varying in- hibiting influence of the same clement in acids and in phenols seems to preclude the acceptance of this suggestion.44 DAVIS : ETHEltIF'lCATLON O F DERIVATIVES OF 6-NAPRTHOL.manner, and that initially they give rise to keto-dihydro-derivatives (Monatsh., 1895, 16, 140). According to this view, P-naphthol would he first converted into the componnd H" and on losing water this would yield P-ethoxynaphthalene. Evidence to a certain extent in favour of this view may be found in the behaviour of @naphthol in contrast with that of phenol. Experiments made by Mr. Panisset, at Dr. Armstrong's suggestion, show t h a t phenol and parabroruophenol may be partially etherificd by means of alcohol and sulphuric acid, but that they yield at most about 25 per cent. of ether. Inasmuch as benzene and its derivatives are less prone to form additive compounds than are naphthalene and its derivatives, and the former are generally less readily attacked than the latter, the fact that phenol is less readily etherified than naphthol is in accordance with the view that addition precedes substitution (compare Armstrong, Trans., 1887, 51, 258 ; Armstrong and Rossiter, Proc., 1891, 7, 89).Now if benzene is represented by KekulB's formula, it is a matter of indifference on which side of a CO,H group the double linking is placed, but i t is not unlikely that, in bromobenzoic acid, for example, it is between the iinbrominated carbon atoms, so that there is a n active ethenoid linking in the immediate neighbourhood of the carboxyl. But it may well be that in P-naphthol no such shift can take place, and t h a t when the linking between positions 1 and 2 is rendered comparatively inactive by the introduction of a.radicle into position 1, the combining power of the compound is greatly reduced. Victor Meyer's observations on the etherifkittion of 2-chloro- or 2-hydroxy-1-naphthoic acid and of 3-chloro- and 3-hydroxy- 2-naphthoic acid are equally in accordance with this view : the former are not attacked whilst the latter are readily etherified. There can be no doubt that 1-derivatives of 2-naphthoic acid will prove equally unsusceptible. Although the structure of the nucleus has a distinct influence, i t would appear that it is rather the specific attracting power of the radicle which is eventually etheritied that becomes affected and diminished by the introduction of negative radicles into the nucleus in its neighbourhood.Armstrong, indeed, has suggested this in ex- planation of the phenomena, observed by Victor Meyer, and has pointed out (Proc., 1896, 12, 42) that '' the formation of a salt is presumably preceded by that of a combination of acid and ' alkaloid,' from which water is then eliminated. J u s t as the acid attractingJAPACONITINE AND THE ALKALOIDS OY JAPANESE ACONITE. 45 power of theNH, radicle in aniline is affected by the introduction, say, of chlorine, so in like manner, the ‘ alkaloid ’-attracting power of the carboxyl group may be assumed to vary as radicles are introduced in its neighbourhood in place of the hydrogen, more particularly in the case of benzenoid compounds.” Whatever the ultimate explanation of the behaviour of benzenoid acids and phenols, there can be little doubt that the phenomena of etherification must be viewed from the same standpoint as those of substitution generally, as there is complete parallelism between them. Armstrong has recently called attention (Proc., 1899, 15, 176 ; Chew. News, 1899, 80, 164) to the effects produced by introducing alkyl radicles in place of the hydroxylic and aminic hydrogen in phenols and smines, and to the remarkable manner in which the formation of sub- stitution derivatives is inhibited. It is clear, in fact, that the influence of radicles in the nucleus on etheritication, and, on the other hand, of etherification on the occurrence of substitution in the nucleus is reciprocal. This is further shown to be the case by the difference in the influence exercised by radicles according t o their position-a single radicle in the meta-position relatively to the carboxyl of benzoic acid exercising less influence on the rate of etherification by alcohol and hydrogen chloride than does the same radicle in the para-position and much less than it does in the ortho-position. It is impossible t o overlook the parallelism which such facts present with the phenomena of substitution expressed iu the well-known “ ortho-para ” and “ meta ” laws. CHEMICAL DEPARTMENT, CITY AND GUILDS OF LONDON IKSTITUTE CENTRAL TECHNICAL COLLEGE.

ISSN:0368-1645    

DOI:10.1039/CT9007700033

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

JAPACONITINE AND THE ALKALOIDS OY JAPANESE ACONITE. 45 V.-Contribution to our Knowledge o f the Aco~zite Alkaloids. Part XV. On Japaconitine and the Alkaloids of Japanese Aconite. By WYNDHABI R. DUNSTAN, F.R.S., and HAROLD &I. READ, Assistant Chemist in the Scientific Department of the Imperial Institute. THE examination of the physiologically active alkaloid which exists in Japanese aconite roots has already formed the subject of several communications to this and other societies ; but in view both of the conflicting statements as to its composition and relationship t o aconitine and of the more recent work which has been carried out by one of US on aconitine and pseudaconitine (the crystalline, toxic alkaloids of46 DUNSTAN AND READ : JAPACONITINE Aconitum NapeZZus and A .ferox respectively), it was thought desirable that the investigation should be extended to the alkaloids of Japanese aconite. Japanese aconite roots seem to have come into commerce about twenty years ago ; they are now imported regularly, and are regarded as more toxic than those of A. Napellus. An exhaustive report by Dr. A. Langgaard on (‘Japanese and Chinese Aconite Roots” was published in 1881 (Arch. Pharrn., 18, 161), and from this it appears that, although the native practitioner employs many varieties of aconite, that most frequently used and exported is (( Kuza-Uzu,” which has been identified by various authorities as A . Chinense, A . Fischevi, and A crystalline alkaloid was first obtained from Japanese aconite roots by Paul and Kiogzett (Pharm. J., 1877, [iii], 8, 173).The alkaloid was soluble in ether, insoluble in water, and formed uncrystal- lisable salts. From the results of a single combustion for carbon and hydrogen, and one nitrogen determination, the formula C,,H,,O,N was adopted. This, however, was not controlled by the analysis of the platinum salt, This alkaloid was said not to suffer hydrolysis into benzoic acid and a basic substance. I n 1879, Wright, Lug, and Menke extended their investigations of the alkaloids of other aconites to those of Japanese aconite. The general results of their work (Trans,, 1879, 35, 387) may be briefly stated as follows : 1. The roots imported from Japan were considerably richor in active crystalline alkaloids, as well as in non-crystalline bases, than A.Napellus. 2. Only one crystalline alkaloid, named japaconitine, was present. This melted at 184-186”, and the formula C66H,8021N, was proposed, the base being regarded as the sesqui-apo-derivative of a parent sub- stance having the formula C,,H,7012N. 3. Japaconitine formed readily crystallisable salts, especially with nitric, hydrochloric, and hydrobromic acids. The hydrobromide has the formula C66H880,1N,,2H&? 4- 5H20. 4. The alkaloid could be entirely extracted from the roots by means of alcohol alone. 5. When hydrolgsed, japaconitine furnished benzoic acid and a new base, jspaconine, which was amorphous, and formed amorphous salts. 6. When either the parent base or the hydrolytic base is benzoylated, a derivative was formed containing four benzoyl groups for every C,, originally present.4. Lycoctonum respectively. For the hypothetical parent base, the formulaAND THE ALKALOIDS OF JAPANESE ACONITE. 47 was proposed, whilst japaconitine, being the sesqui-apo-derivative, was given the formula I n 1885, K. F. Mandelin examined a specimen of japaconitine pre- pared by Merck, and stated that the alkaloid from Japanese roots agreed in chemical and physical behaviour with aconitine derived from A . Xape llus. Liibbe '(Chem. Centr., 1890, ii, 14s) arrived at the same conclusion, working with material which he extracted from '' kuza-uzu " roots im- ported direct from Japan. The alkaloid which he isolated crystal- lised in rhombic prisms melting a t 183-184'. It must be noted that the proof of the identity of his base with that obtained from A .Napellus by Wright rests on the results of a single combustion, Still more recently, Freund and Beck (Bey., 1894, 27, 723) have stated that " they have no doubt of the identity of the alkaloid from both sources," although they do not give any details of the work which led them to this conclusion. The roots from which we have extracted the alkaloid used for this investigation were purchased in commerce as Japanese aconite roots. Mr. E. M. Holmes, F.L.S., Curator of the Pharmaceutical Society's Museum, kindly examined a specimen of these, and informed us that they are undoubtedly ordinary Japanese roots, such as described by Langgaard (Zoc. cit., and Pharrn. J., 1881, [iii], 11, 1043), and known in Japan as " kuza-uzu." I. JAPACONITINE.Extraction of the Alkaloid. We have extracted the alkaloid by the following method. The finely ground root is percolated with a mixture of amyl alcohol and wood spirit, in the proportion of 1 part of the former to 5 of the latter. The wood spirit is distilled from the mixture under reduced pressure on a water-bath, the temperature of which is kept below 60'; the residual solution of the alkaloids in amyl alcohol is extracted with dilute (0.5 per cent.) sulphuric acid, and the latter thoroughly washed with ether to remove all traces of aruyl alcohol. The alkaloid is now fractionally precipitated by sodium carbonate or ammonia from the aqueous solution of the sulphate, and is extracted by shaking with ether. When the whole of the bases soluble in ether have been removed, the extraction is continued with chloroform.The aqueous mother liquors still contain a small quantity of alkaloid, The complete exhaustion takes a considerable time.48 DUNSTAN AND READ : JAPACONITINE a certain proportion of which may be removed by saturating the solu- tion with sodium sulphate and then shaking with chloroform, The ethereal solution is now washed with water to remove traces of alkali, and calcium chloride is added. The latter serves a double purpose in precipitating most of the colouring matter extracted by the ether, and at the same time drying the solution. Since the calcium chloride does not show any tendency to combine with the alkaloid, this method is very advantageous in avoiding a great deal of subsequent purification. The dried and filtered solution is caref iilly distilled, and, when sufficiently concentrated, the nearly pure jap- aconitine crystallises out in minute, colourless rosettes of prismatic needles.Prom the mother liquor, a further quantity of crystalline japaconitine may be obtained. The best method for working up the solution in chloroform is to wash it with water to remove traces of alkali, evaporate to a small volume, drive off the residual chloroform with a current of air, and then to add ether to the pale brown varnish which remains. The greater part of the varnish dissolves in the ether, and on pouring off and evaporating the latter solution, more crystal- line japaconitine is obtained. The extract left undissolved by the ether will be described later (see page 62).Proprt ies of Japaconitine. The crystalline base obtained in this manner melts at about 195-196'. For the final purification, it is converted into a salt, preferably the hydrobromide, by dissolving in the diluted acid and evaporating the neutral solution in a vacuous desiccator until crystals form. The crystallisation may be considerably hastened by well stirring the solution with a glass rod. We have found that, in evaporat- ing the solution, it is well to avoid entirely the aid of heat, since the saving of time ef3Fected is more than counterbalanced by the discolora- tion of the resulting salt. Having recrystallised the salt, either from water or from a mixture of alcohol and ether, until the melting point remains unchanged, the base may be regenerated in the usual manner.When thus purified, japaconitine crystallises from ether, alcohol, or chloroform in colourless, anhydrous rosetkes of needles, The base recrystallised from ether was analysed. 05518 lost 0.002 after 30 minutes a t 100'. Loss = 0.362 per cent 0.6267 ,, 0.0003 ,, 90 ,, looo, LOSS =0*047 ,, The base therefore does not combine with the solvent. Many attempts were made to obtain large crystals for crystallo- graphic measurement, but these, unfortunately, have been unsuccessful. This difficulty in obtaining large crystals of japaconitine contrastsAND THE ATJKATAOIDS OF JAPANESE ACONITE. 49 sharply with the ease with which, by the same methods, t'he well- defined, hexagonal prisms so characteristic of nconitine are obtained. The largest jnpaconitine crystals we have succeeded in preparing were obtained by the gradiial precipitation of a solution in dry chloroform with light petroleum.These were kindly examined for ns by Mr. W. J. Pope, who describes them as follows : '' The crystals of japaconitine are very small, transparent, colourless needles possessing a brilliant lustre; the sides of the needles are made up of two pairs of parallel prism faces. A number of measure- ments of the prism angle showed this to have the value 77" 35'- 77" 54' ; no measurements in which the end faces of the needles were involved could be made owing to the minute size of these end faces. " The extinction in the prism faces is straight, and on examination in convergent light the interference figure of a uniaxial substance, or of a biaxial substance with a very small optici axial angle, is seen ernerg- ing in the angle between the prism faces; the double refraction is negative in sign.On examining the crushed crystals microscopically, pieces may sometimes be found in which the optic axial interference figure occupies the centre of the field; some pieces show a uniaxial figure, whilst in others the interference figure is biaxial with a very small optic axial angle. ''On comparing the above description with that of aconitine given by Tutton (Trans., 1891, 59, 288) or of pseudaconitine by Pope (Trans., 1897, 71, 352), co points of similarity are traceable ; it must there- fore be concluded that japaconitine is crystallographically different from both aconitine and pseudaconitine." Japaconitine is very soluble in acetone, wet alcohol, and chloro- form, and, when amorphous, in dry alcohol and in ether.When crystalline, it slowly dissolves in boiling ether and alcohol. I t is almost insoluble in dry light petroleum, and is but slightly soluble in water. It is readily crystallised by the addition either of water to its solution in alcohol or in acetone, or of petroleum t o its solution in chloroform, or in alcohol and ether. The pure base melts at 204.5" (corr.) to a clear, pale yellow liquid, which, a few seconds later, effervesces rapidly with the evolution of acetic acid. XpeciJic Rotation of Japaconitine Lubbe (Zoc. cit.) has stated that a 3 per cent. alcoholic solution of japaconitine is inactive. We find, on the contrary, that both alcoholic and chlorotorm solutions are dextrorotatory, like those of aconitine (Dunstan and Ince, Trans., 1891, 59, 281).VOL. LXXVIJ. E50 DUNSTAN AND READ : JAPACONITINE ( I ) In chloroform. [a], = + 20.26' (mean). ,lo" = + 0.622' ; I = 2 dcm. ; c = 1.602 ; [all: + 19.41'. d 5 " = +0.6'; 1=2 dcm.; c=1*42; [a]: +21*12O. ,lSSO = + 17" 2'; I= 2 dcm. ; c=0*605 ; (2) In alcohol. [aID= +23*6O. The specific rotatory power of jspaconitine is therefore much greater than that of aconitine, which is only + 11Oin alcohol (Dunstan and Ince, Zoc. cit.), whilst in chloroform we find it to be + 14.61Oat 18'. + 2306~. Determination of Methoxyl Groups in Japaconitine. The number of methoxyl groups in the base was estimated in the 0.1806 gave 0.268 AgI. CH,O = 19.58. C,,H,707N(OCH,)4 requires CH,O = 19.1 6 per cent.usual manner, using a slight modification of Zeisel's method. 0.1852 ,, 0.279 AgI. CH,O= 19.87. Japaconitine therefore, like aconitine, contains four methoxyl groups. Combustions of Japaconitine, The pure base was burnt in a current of oxygen, using cupric oxide 0.2857 gave 0.6534 CO, and 0.2005 H20. and a silver spiral. C = 62.37 ; H = 7.79. 0.2814 ,, 0.6410 CO, ,, 0.1790 H,O. C = 62.12 ; H=7*06. 0.1888 ,, 0.4338 CO, ,, 0.1198 H,O. C=62.66; H=7.05. 0.2049 ,, 0,4740 CO, ,, 0.1322 H20. C = 63-09 ; H= 7.16. Mean, C = 62.56 ; H = 7-26 per cent. Two combustions for nitrogen by the absolute method, using lead ehromate, furnished the following data : 0.3035 gave 8.892 mg. moist nitrogen. N= 2-92. 0.3105 ,, 7.864 mg. moist nitrogen. N= 2.53.C34H490,,N requires C = 63.06 ; H = 7-57 ; N = 2.16 per cent. We therefore adopt this formula provisionally as best representing the composition of japaconitine. This formula differs only very slightly from that proposed for aconitine by Freund and Beck (Ber., 1894,27, Salts of Japaconitine. 433). Japaconitine, like aconitine, furnishes a number of well crystallised salts. Japaconitine hydvochlmide is readily obtained by dissolving the pure base in dilute hydrochloric acid, the solution being left faintly acidAND THE ALKALOIDS OF JAPANESE ACONITE. 5 1 to litmus. The salt crystnllisee out in plates melting at 149-150'. When crystallised by dissolving in alcohol and precipitating with ether, lustrous rosettes of hexagonal plates, melting at 1 49-150°, are obtained.The salt crystallised from aqueous alcohol and ether contains three molecular proportions of water. 0.7800 lost 0.0640 after 1; hours at 105-110°. 0.3230 gave 0.0604 AgC1. Cl=4.62. C,,H,,O,,N,HCl+ 3H20 requires C1= 4.81 ; H20 = 7*3 per cent. It has already been shown (Dunstan and Ince, Zoc. cit., Dunstan and Cam, Trans., 1897, 71,350) that although aconitine and pseudaconitine are dextrorotatory, their salts are lsvorotatory. Japaconitine also exhibits this peculiarity. The tri-hydrated salt dissolved in water was used for the following determination : Loss =8*2. = - 1.466' ; I = 2 dcm. ; c = 3.076 ; [ u ~ ~ " = - 2 3 . 8 O . A determination of the specific rotation of aconitine hydrochloride was made a t the same temperature for comparison : u1V= - 1.433'; I = 2 dcm.; c = 2.315 ; [cty:= - 30.9'. Japaconitir~e hydrohomide crystallises readily from water, or from alcohol and ether, The crystals deposited from the latter solvents are very similar to those of the hydrochloride, being rosettes of hexagonal plates. The salt crystallised from aqueous alcohol and ether contains four molecular proportions of water. 1.2860 lost 0.1044 after 2 hours at 105-110'. 0.3060 gave 0.0726 AgBr. C,,H,,O,,N,HBr + 4H20 requires Br = 10.00 ; H,O = 9.00 per cent. Japaconitine hydriodide crystallises from water in minute rosettes melting at 195-197'. When recrystallised from alcohol and ether, the salt melts at 207*5-208*5°. Japaconitine nitrate crystallises from water in minute rosettes of needles melting a t 173-177'. When recrystallised from alcohol and ether, the salt contains one molecular proportion of water and melts a t 194', effervescing sharply a t 199'.The water of crystallisation is not lost until the salt is heated to 115--120'. When dried, the salt melts at 172-173'. Loss =8*11. 0,3320 ,, 0.0278 ,, ,, 100-110'. LOSS ~ 8 . 3 7 . Br = 10.09. After being dried at looo, 0.5315 lost 0.01 a t 115-120' for 18 hours. The hydrated salt gave the following numbers on analysis : Loss = 1.9 per cent, E 252 DUNSTAN AND READ : JAPACONITINE 0.1762 gave 0.3620 CO, and 0.1 145 H,O. C = 56.03 ; H = 7-29. C,,H,SOllN,HNO, + H,O requires C = 56.04 ; H = 7.14 ; H,O = 2.47 per cent. Japacondtine thiocyanate is prepared by adding an aqueous solution of ammonium thiocyanate to an aqueous solution of japaconitine hydrochloride, The crystalline salt, melting at 1 20°, is immediately precipitated if the alkaloidal solution is strong.When dissolved in alcohol and precipitated with water, the salt crystallises in lustrous needles. These melt at 190-1 92'. Aconitine thiocyanate, crystal- lised from water, melts at 145'; crystsllised from alcohol and ether, it melts at 193-195'. Japaconitine aurichlovide is obtained as a bulky, amorphous, canary- yellow precipitate by the addition of an aqueous solution of auric chloride to an aqueous solution of japaconitine hydrochloride slightly acidified with hydrochloric acid. The precipitate is quickly filtered, washed with water until the washings are neutral, and then dried in a vacuum. The amorphous aurichloride is readily soluble in alcohol, chloroform, or acetone, slightly soluble in water.A few minutes after the amorphous salt is dissolved in a little alcohol, the greater part of it separates in minute, golden-yellow, opaque needles which melt at 231' (uncorr.). The same salt may be prepared by precipitating (1) methyl or ethyl alcohol, or acetone solutions with ether or with water, (2) chloroform solutions with ether or with ether and petroleum. In each case, crystalline japaconitine aurichloride, melting at 231', is obtained. On two occasions we have obtained yellow crystals of an auri- chloride melting at a much lower temperature. First, by dissolving the amorphous salt in dry chloroform and allowing the solvent to evaporate spontaneously, yellow prisms separated. These melted in- distinctly at 152-154'.They were recrystallised by dissolving in chloroform and precipitating with ether, when similar prisms melting at 153' were obtained. On attempting to recrystallise these from alcohol, it was found that they Separated from that solvent almost immediately after solution, in the opaque, small, canary-yellow rosettes which we find t o be so characteristic of japaconitine auri- chloride. On the second occasion, a crystalline, golden-yellow aurichloride, melting indistinctly at 154-160°, was obtained after the addition of dry, light petroleum to an alcoholic solution of the amorphous salt. These crystals dissolved in chloroform, and on the addition of ether were precipitated in opaque rosettes melting at 231'. They were therefore japaconitine aurichloride.One of us has already shown (Dunstan and Jowett, Trans., 1893, These rosettes melted at 231'.AND THE ALKALOIDS OF JAPANESE ACONITE. 53 63, 994) that aconitine aurichloride may exist in three distinct iso- meric forms, the nature of the solvent and of the precipitant being apparently the factors which determine the production of these modi- fications. Although we have been unable to find the exact conditions for the formation of the salt of japaconitine melting at 154-156", it is evident from these results that japaconitine aurichloride exists in a t least two isomeric forms. The stable modification melting a t 231", being that most generally produced, we propose to name japaconitine a-aurichloride, and the unstable variety, melting indistinctly at 154-1 6O0,japaconitine P-ccurichZo&te.The melting points of aconitine a-, /3-, y-aurichlorides are 135.5O, 151-152", and 176" respectively. I n this connection, i t is of interest to note that japaconitine and aconitine, when mixed, may, by a tedious process, be separated by repeatedly fractionating the aurichlorides of the mixed bases by crystallisation from alcohol and from a mixture of alcohol and ether. Japaconitine a-aurichloride, melting a t 231°, crystallises out in the first fractions, and aconitine P-aurichloride, melting at 151-152" in the later fractions. Japaconitine a-aurichloride forms neither a hydrate nor an alcoholate. The crystalline salt, after being dried on a porous tile, lost no weight, either when allowed to remain in a vacuous desiccator for several days, or when heated in the water oven.A determination of the gold and chlorine gave the following results : 0.2408 gave 0.0474 AU and required 9.8 C.C. of N / l O AgNO, (of which 983 C.C. =3*55 C1) for complete precipitation of the chlorine. Whence AU = 19.68 ; C1= 14.69 per cent. The salt was burnt for carbon and hydrogen, but the determina- tion of the latter was of no value. 0,2014 gave 0.3010 CO,. C= 40.76 per cent. per cent, C3PH49011N,HAuC14 requires AU = 19.95 ; C1= 14.38 ; C = 41 *33 Physiological Action of Japaconitine. The physiological action of japaconitine is being investigated by Professor Cash. It may be etated here that it is an intensely toxic alkaloid which, in general, acts like aconitine, the resemblance between the two alkaloids being very close indeed.It produces the characteristic tingling of the lips, tongue, and skin, with long-continued tactile and thermic perception at the seat of applicatioii. It slows and then accelerates the heart, producing a sequence of ventricular upon auricular action. The death occasioned by it appears, however, to be primarily respiratory. Whilst the lethal59 DUNSTAN AND READ : JAPACONITINE dose of japaconitine towards frogs (Ranu esculenta and R. tempomria) and mammais is not identical with that of aconitine, the difference in toxicity is not great, moreover the variation in the effect produced by an equal dose is one rather of degree than of kind. Action of Methyl Iodide on Japaconitine. MethyGapaconitine. When japaconitino is heated in a closed tube to a temperature of 110-112' with a slight excess of methyl iodide, a crystalline methiodide is formed.This methiodide crystallises from the mother liquor with extreme readiness in large rosettes of colourless needles which melt 0.2240 dissolved in alcohol and precipitated with silver nitrate, st 224-225'. furnished 0.0690 AgI. I = 16.64. C,4H4,011N,CH3T requires I = 16.09 per cent. On adding dilute potash to an aqueous solution of japaconitine meth- iodide, a flocculent precipitate of rnethygapaconitike, C3,H,,0,,N*CH3, is thrown down. This base may be readily extracted by chloroform or ether, and crystallisqs from the latter in minute rosettes of colourless needles, which melt a t 206'. A combustion of the pure base furnished the following data : 0*1142 gave 0.2670 CO, and 0.0790 H,O.Methyljapaconitine ccuyichloride crystallises from a mixture of alcohol and ether in minute rosettes which melt at 223-225O. The readiness with which japaconitine furnishes a methyl derivative is another point of difference between it and aconitine (Dunstan and Jowett, Proc., 1894, 10, 96). C = 63.76 ; H = 7.69. C35H51011N requires C = 6354 ; H = 7.71 per cent. Action of Acetyl Chloride on Japaconitine. By allowing acetyl chloride to act on japaconitine for some hours a triacetyl derivative melting at 166' is formed. I n addition to tbis, a small quantity of a derivative very soluble in aIcoho1, and melting at 184-186', is produced, but the amount obtained was too small for further examination. Priucety$'apaconitine, C34H46011N( COO CH,),, crys tallises in colourless rosettes melting at about 166'.It is not very soluble in alcohol, and may thus be easily separated from the derivative melting at 184-186'. It is soluble in ether and in chloroform, but insoluble in water. Tricccetyljccpaconitine. 0.1043 gave 0.2357 CO, and 0,0697 H,O. 0-2475 C = 61-63 ; H = 7.41. ,, on hydrolysis with potash, 29.5 per cent. acetic acid. CaH55014N, requires C = 62.09 ; H = 7-1 1 ; C2H,0, = 31.04 per cent.AND THE ALKALOIDS OF JAPANESE ACONITE 55 11. JAPBENZACONINE. Hydrolysis of Japaconitine. When japaconitine is hydrolysed, it furnishes acetic acid, and a new crystalline base, which from its analogy to benzaconine, the hydrolytic base from aconitine, we purpose naming jupbenxaconine.This hydro- lysis may be effected in neutral, in alkaline, or in slightly acid solution. The last is the most convenient, since in the presence of alkalis, the new base, japbenzaconine, readily suffers further hydrolysis into benzoic acid, and another base, japaconine (vide ilzfra). Although any of the salts of japaconitine may be used for the hydrolysis, we have found the sulphate to give the most satisfactory results. 0.41 22 gram of japaconitine was neutralised with dilute sulphuric acid and the solu- tion heated in a sealed tube for 9 hours at 115-130'. The slightly discoloured solution was then neutralised with soda. A definite amount of decinormal sulphuric acid was now added and the benzoic acid, a small quantity of which is invariably produced, removed by shaking with benzene.The aqueous portion and the washings from the benzene were titrated with soda (1020 C.C. = 4.9 H2S04) of which 6.6 C.C. were required, equivalent to 9-41 per cent. acetic acid. The equation C34H49011N + H,O = C2H,02 + C,,H,701,N requires 9-27 per cent. The identity of the acid was proved by an analysis of its silver salt. 0.1485 gave 0.0957 Ag. C2H,02Ag requires Ag = 64.66 per cent. The identity of the benzoic acid, extracted by benzene, was deter- mined by its melting point, which was 121', as well as by other of its physical characters (vide infra). No methyl alcohol or other product could be detected. The hydrolysis, therefore, takes place according to the equation given above. Wright and Luff do not record the production of acetic acid during the hydrolysis of japaconitine, nor did they observe the formation of japbenzaconine.Their account of the hydrolysis is that the japaconitine is decomposed, forming japaconine and benxoic acid. Ag = 64.44. Properties of Japbenxaconine. The new base is precipitated from the aqueous solution of its salts by the addition of alkali, and may be partially removed by shaking with ether. Its complete removal necessitates a vigorous shaking with chloroform. By the evaporation of its ethereal solution, jap- benzaconinc is obtained as a, colourless varnish. The latter readily56 DUNSTAN AND READ : JAPACONITINE dissolves in dilute hydrochloric acid, the solution, after partial evapo- ration and stirring, yielding a crystalline salt. Although no difficulty attends the crystallisation of the salts of japbenzaconine, many at- tempts were made to crystallise the base before it was accomplished.The following method finally proved successful. A slight excess of dilute ammonia was added to an aqueous solution of the pure hydrochloride, the white flocks of the precipitated base dissolved by shaking with ether, and the ethereal solution washed and dried over calcium chloride. The dried solution was filtered into a stoppered bottle, and sufficient light petroleum added to produce a faint opalescence. A considerable quantity of amorphous japbenzaconine separated, and after standing 2 or 3 days the clear mother liquor was poured off into another bottle. After several days, minute rosettes appeared. These melted at 176"; further small quantities of crystals having the same melting point were obtained by the careful addition to the mother liquor of small quantities of light petroleum. When purified by recrystallisation from a mixture of ether and petroleum, the base melted a t 183'.It could also be crystallised by dissolving in alcohol and precipitating with water. The crystals thus obtained melted at about 180'. Jspbenzaconine, therefore, diff ers very markedly from benzaconine in the fact that it may, when pure, be fairly readily crystalliaed. The only well-defined crystals we have obtained were rhombohedra1 plates. When dissolved in dilute acids, the solution is distinctly bitter, and quite free from the tingling sensation so characteristic of japaconitine and of aconitine. The base, crgstallised from ether, is anhydrous.0.1967 lost 00003 after 1 hour at 103", that is, 1.53 per cent. Spec;fic rotation of japbenxmonine. I n alcohol. C Z ~ * ' ~ = + 1.633'; 1=2 dcm. ; c=2.033; 1aJ1g5"= f40.16". The specific rotation of benzaconine is + 4.48 (Dunstan and Harrison, Japbenzaconine is therefore nearly ten times Trans., 1893, 63, 443). more optically active than benzaconine. Combustions of japbenzaconine : 0.1922 gave 0.4510 CO, and 0.1505 H,O. C= 63.99 ; H= 8.7. 0.1857 9, 0.4365 CO, ,, 0.1252 H,O. C=64*10; H=7*49. C,,H&,,N requires C = 63.47 ; H = 7.76. Salts of Japbenxaconine. The salts of japbenzaconine crystallise with extreme readiness. Japbenxaconine hydrocklo&ie crystttllises f 1'0111 water in Minute When recrystallised from alcohol and rosettes melting at 244-2459AND THE ALKALOIDS OF JAPANESE, ACONITE.57 ether, the melting point is raised t o 253'. alcohol and ether, contains one moleciilar proportion of water. The salt, crystallised from 0.2234 hydrated salt lost 0.0044 H,O after 1; hours at 100'. 0.2009 hydrated salt lost 0.0057 H,O after heating hour at 110'. 0.1950 hydrated salt gave 0.0416 AgC1. Cl=5*27. H,O = 1.97. H,O = 2.33. 0.2066 ,, ,, 0,0446 AgC1. C1= 5.34. C,,H,70,0N,HC1 + H,O requires H,O = 2.73 ; 01 = 5.38 per cent, Specific rotation of the hydrated hydrochloride in water. d2"" = - 0.8'; .J= 2 dcm. ; c = 2.028 ; [ a]:30 = - 19-73' The specific rotation of benzaconine hydrochloride, dissolved in water, was taken for comparison. ~~'23" = 0.7C5O ; I = 2 dcm. ; c = 1.492 ; [ a]:30 = - 25.1 3'.Combustions of the anhydrous hydrochloride. 0,1894 gave 0.4175 CO, and 0.1240 H,O. C = 60.11 ; H = 7.27 0.1925 ,, 0.4242 CO, ,, 0.1281 H,O. C=60*09 ; H=7*39. C,,H,70,0N,HC1 requires C = 59.95 ; H = 7.49 per cent. Jnpbenxccconisie Iqdrobrornide crystallises from water in minute prisms, and- from alcohol and ether in rosettes melting indistinctly Japbenzaconine aurichloride is precipitated in amorphous, yellow flocks on mixing aqueous solutions of auric chloride and of japbenz- aconine hydrochloride. The dried amorphous salt crystallises immedi- ately upon t h e addition of dry alcohol, the crystals melting at about 2 12O. The salt may be readily crystallised from alcohol or chloroform hy precipitation with ether. The melting point varies with the nature of the solvent, the crystals from alcohol melting at 219', and those from chloroform and ether at 288'.By the addition of water to a n alcoholic solution, the salt is precipitated in oily drops. The crystal- line aurichloride is anhydrous. Analysis of the salt furnished the following results. 0.3320 gave 0.0675 Au and 0.189 AgCl. :tbout 205-217'. Au= 20.33 ; C1= 14.08. C,,H,70,0N,HAuCI, requires A u = 20.84 ; C1= 15.02 per cent. The hydrochloride of the regenerated base crystallised readily from water, melted at 246', and was identical with japbenzaconine hydro- chloride. A urichlo?.-jcc3,beiLxa con ine. -1V he 11 a I I a1 coholic so1 u ti on of j ap- benzaconine aurichloride, t o which a few drops of light petroleum58 DUNSTAN AND READ : JAPACONITIXE have been added, is allowed to stand for about a week, colourless, well- defined, lustrous octahedra are obtained.These octahedra, after re- crystallisation from alcohol and ether, melt a t 178" with the separation of a considerable quantity of gold. The mother liquor from which these crystals separated furnished a small quantity of colourless rosettes of needles melting at about 230" and containing gold. The quantity obtained was unfortunately too small for further examination. The octahedra, melting at 1 7 8 O , crystallise without any attached solvent. An analysis furnished the following data : 0.2332 gave 0.053 Au and 0.078 AgC1. C,2H,,0,0N=AuC12 requires Au = 22.6 ; C1= 8-23 per cent. The hydrochloride of the regenerated base crystallised from alcohol and ether in beautiful, lustrous rosettes melting a t 252-253", and identical with j ap benzaconine hydrochloride. Au=22.72 ; Cl=&27 III.JAPACONINE. Hycli*oZysis of Jccpbenxaconine. Japbenzaconine is slowly hydrolysed by strong alkalis or by cold dilute sulphuric acid, more rapidly on heating. The complete hydrolysis is, however, by no means easy to effect, since the continued heating with alkalis leads to the resinification of the hydrolytic products. This is obviated to a certain extent by carrying out the hydrolysis either in alcoholic solution, using an alcoholic solution of sodium hydroxide, or in a sealed tube. The former method was the one which we foucd most satisfactory, and gave fairly concordant results when the percentage of benzoic acid was determined.2.9015 grams of japbenzaconine were dissolved in alcohol, warmed, and a 30 per cent. alcoholic solution of sodium hydroxide added. The mixture was allowed to stand for 24 hours. Dilution with water pro- duced no precipitation of japbenznconine, showing that the hydrolysis was complete. The solution was neutralised with sulphuric acid, the alcohol removed by evaporation on a water-bath, and the aqueous solu- tion, after acidifying with sulphuric acid, extracted with benzene. The benzene solution was extracted with dilute soda, and the latter acidified with sulphuric acid and extracted with ether. The dried ethereal solu- tion furnished, after careful evaporation, 0,589 gram of benzoic acid (m. p. 121*5O) =19*98 per cent. The following equation therefore represents the hydrolysis, the calculated quantity of benzoic acid being 20.16 per cent.C52H47010N + HgO = C,H,* CO2H + C'25H,,O,N. The acid solution from which the benzoic acid had been removedAND THE ALKALOIDS OF JAPANESE ACONITE. 59 was now rendered alkaline, and extracted, first with ether and then with chloroform. The ether removed nothing from the solution, and the chloroform only a trace of alkaloid which was readily extracted again by shaking with water. The residual solution was therefore neutralised with sulphuric acid, and evaporated to dryness. The residue, most of which was sodium sulphate, was extracted with alcohol, the alcoholic solution made alkaline with sodium hydroxide, evaporated to dryness, and the brown alkaloidal residue dissolved in chloroform ; the chloroform solution gave, after evaporation, a very hygroscopic, dark brown varnish.This varnish, which was strongly alkaline to litmus and readily reduced Fehling's solution, was purified by neutralising with aqueous sulphuric acid and removing the greater part of the colouring matter by boiling the solution with charcoal. The pure base, japaconine, was obtained by precipitating the solution of the sulphate with barium hydroxide, filtering, and evaporating the aqueous solution. It was finally purified by the fractional precipitation of a solution in chloroform with ether. Most of the colouring matter is precipitated in the first fractions, the later fractions being almost colourless japaconine. Pwperties and Composition of Japc6conine. Thus purified, japaconine is a colourless, exceedingly hygroscopic, powder which we have so far been unable to crystallise.It is readily soluble in water, alcohol, chloroform and acetone, but almost in- soluble in ether and petroleum. It melts indefinitely between 9 7 O and 100'. Its specific rotation in water is + 1 0 . 8 8 O . algO = +0*4"; Z=2 dcm.; c=1.837; [ u ] F = +10*88O. Combustions of the amorphous japaconine. 0.2010 gave 0.4480 CO, and 0.1460 H,O. C = 60.78 ; H = 8.07. 0.1855 ,, 0.4058 CO, ,, 0,1193 H,O. C = 59.65 ; H= 7.14. 0.1634 ,, 0.3645 GO, ,, 0.1108 H,O. C = 60.17; H= 7.53. C,,H,,O,N requires C = 59.88 ; H = 8-58 per cent. The salts of japaconine crystallise with great difficulty. None crystallise from water, and those which we have crystallised from alcohol and ether are so hygroscopic that we have, unfortunately, been unable t o examine them completely.Japaconine hydrobromide crystallises from alcohol and ether in rosettes of colourless, triangular plates melting sharply at 22 lo. Jccpaconine hydrochloride crystallises froin alcoholic solution after the addition of ether. Japaconine oxalute crystallises in colourless, dumb-bell shaped rosettes.60 DUNSTAN AND READ$: JAPACONITlNE A strong aqueous solution of the hydrochloride gives no precipitate with auric chloride or platinic chloride, arid the aqueous solution of the aurichloride is quickly reduced. Fehling's solution is also reduced when boiled with a solution of japaconine. In its general behaviour, japaconine resembles aconine ; its salts, however, crystallise much less readily than those of aconine.IV. PYROJAPACONITINE. Efeect of Heat on Japaconitine. It has already been shown (Dunstan and Carr, Trans., 1894, 65, 1'76 ; 189'7,71, 350) that aconitine and pseudaconitine decompose when heated at their melting points, furnishing acetic acid and new bases which were named pyraconitine and pyropseudaconitine respectively. We find that japaconitine behaves in a similar manner. When heated at about 200-210' for 10 minutes, the base gradually darkens, and finally melts, with the evolution of acetic acid. The amount of the latter, estimated by titration with decinormal soda solution, varies from 8.4 t o 8.9 per cent. The amount required for a loss of one molecule of acid from one molecule of japaconitine (C,,H,90,,N - C,H,O,) = 9-27 per cent.I n addition to the loss of the acetic acid, there is almost invariably a further loss varying from 3 to 4-5 per cent., the nature of which has not been determined. The dark brown varnish which remained after the evolution of the acetic acid was readily purified by dissolving in dilute sulphuric acid, exactly neutralising the solution with soda, and boiling with charcoal for a few minutes. Ammonia was added to the colourless solution thus obtained, and the bulky, flocculent precipitate of the pyro-base extracted by shaking several times with ether and finally with chloroform. The ethereal solution was dried with calcium chloride and evaporated to dryness, a pile yellow varnish being thus obtained. This varnish was dissolved in dilute bydrobrornic acid, and the solution evaporated t o a small bulk on a water-bath.After vigorous stirring, minute crystals of the salt separated, which melted a t 240° (pyraconitine hydrobromide melts at 282'). The base was regenerated and extracted with ether, and the ethereal solution, after partial evaporation, dried with calcium chloride, filtered into a stoppered bottle, and light petroleum added until a n opalescence formed. Colourless needles of the base crystallised after standing a few days. These, after crystallisation, melted at 167-- 168'. The alkaloid, like pyraconitine, is lzvorotatory. 2 0 " = - 3.33' ; Z = 2 dcm. ; c = 2.529 ; [u]z = - 65.89.AND THE ALKALOIDS OF ,JAPANESE ACONITE. 61 On combustion, tohe crystalline base furnished the following results : 0.1081 gave 0.2582 CO, and 0.0685 H,O.C=G5*14; K= 7.04. 0.1079 ,, 0.2572 (20, ,, 0.0652 H,O. C=64*92 ; H=6.71. C32H4,OgN requires C = 65.41 ; H = 7.66 per cent. A methoxyl determination by Zeisel's method shows that pyro- 0.1950 furnished 0.2810 AgI. C3,H,,0gN requires, for 3 inethoxyl groups, CH,O = 15.8 per cent. japacotdine, like jspaconitine, contains four methoxyl groups. CH,O = 19.00. 9 9 9 9 4 ?, ,, CH30=21-l ,, Pyrojapaconitine furnishes well crystallised salts. P?pojapaconitine hydrobromide sepasates from water in minute, colourless crystals melting a t 241". When this salt is recrystallised by dissolving in alcohol and precipitating with ether, it melts at 208-2209", but, after solidification, it remelts at about 237-238'. The melting point of this (208') variety is unchanged by repeated recrys- tallisation from dry alcohol and ether, but when recrystallised from water the salt melts at 241'.The salt, crystallised from its aqueous solution, contains two mole- cular proportions of water, one only of which is lost a t 100". 0.7140 lost 0.0293 H,O after 2 hours at 100'. H,O=4.10. 0.4415 ,, 0.0180 H20 ,, 70 minutes a t 100-130°. H,O = 4.8. The speci6c rotation of pyrojapaconitine hydrobromide in water is - 102.5°. - - 5.616'; I = 2 dcm. ; c = 2.7388 ; [ CC]~D~.= - 102.5". On analysis, the salt, dried a t looo, furnished the following data : 0-1815 gave 0.3706 C02 and 0*1030 H,O. 0.1910 , I 0.3910 CO, ,, 0.1110 H,O. C=55*83 ; H = 6.45. 0.4235 ,, 0.1160 AgBr. Br = 11.65. C = 55 68 ; H = 6-30. C3,H,,OSN,HBr + H,O requiresC = 55.97; H = 6.99; Br = 11.66 per cent.Unsuccessful attempts were made to prepare an anhydrous hydro- bromide by a direct method. Pyrojapaconitine aurichloride is precipitated in bulky, yellow flocks on the addition of aqueous auric chloride to an aqueous solution of pyrojapaconitine hydrochloride. It crystallises very easily from its solution in alcohol or chloroform after either spontaneous evaporation or the addition of ether. The melting point of the salt varies with the solvents from which it is crystallised, t h a t from chloroform melt- ing at about 160-161', and that from alcohol and ether at about 188-1 89".62 DUNSTAN AND READ : JAPACONITINE The following results wore obtsinetl by the analysis of the salt (m. p. 360-161") crystallised from chloroform : 0.3389 gave 0.0697 Au and 0*2025 AgC1.Au = 20.56 ; C1= 14.78. The salt (m. p. 188-189') crystallised from alcohol and ether gave 0.1742 gave 0.2656 CO, and 0.0740 H,O. C = 40.01 ; H = 4.72. 0.1694 ,, 0.2502 CO, ,, 0.0696 H20. C=40*28 ; H=4*56. C32H4,0gN,HAuCl, + H,O requires C = 40.63; H = 5.07; AU = 20.84 ; C1= 15.02 per cent. C32H,509N,HAuC'1, requires C = 41 -43 ; H = 4-96 ; AU = 21 -25 ; C1= 15-31 per cent. the following data : No aurichlor derivative could be obtained. V. PYBOJAPACONINE. Hydrolysis of Pyrojapaconitine. Pyrojapaconitine is hydrolysed with extreme readiness by alkalis, The products of the hydrolysis being complete in less than an hour. the reaction are benzoic acid and a new base, pyrojapaconine, C,,H,,O,N + H20 = C6H5* C02H + C2,H4,0,N.Pyrojapaconine may be extracted from its aqueous alkaline solution by shaking either with ether or chloroform, preferably the latter. Light petroleum precipitates the substance from the ethereal solution in colourless, amorphous flakes melting at about Z 23 -1 2 8 O . The base is very deliquescent. Its specific rotation is - 73.96'. a2'= -4.3'; Z=2 dcm.; ~ = 2 . 9 1 0 6 j [a]r=73.96°. Combustions of pyrojapaconine furnished the following results : 0.1495 gave 0.3385 CO, and 0.1060 H,O. C! = 61-75 ; H = 7 87. 0.1499 ,, O933'70 CO, ,, 0.1035 H,O. C=61*31; H=7*67. C,,H,,O,N requires C = 62.1 1 ; H = 8.48 per cent. All attempts to crystallise either the base or its salts were unsuccess- The aurichloride is soluble in warm water, but separates in a It is soluble in alcohol, and the deep yellow ful. vitreous mass on cooling.solution becomes colourless after long standing. TI. THE AMORPHOUS ALKALOIDS OF JAPANESE ACONITE. In working up the crystalline japaconitine used for the preceding Work, a small amount of an amorphous base was accumulated. This base furnished a hydrochloride, which crystallised readily fromAND THE AJ,RAJ,OIDS OF JAPANESE ACONLTE. 63 water in the minute crystals so characteristic of japbenzaconine hydrochloride, and melted at 241-242'. By rccrystallisation from alcohol and ether, the melting point was raised to 24GD. This is the melting point of japbenzaconine hydrochloride. I n order t o completely confirm the identity of this substance, a small quantity was converted into the aurichlor derivative by adding light petroleum to an alcoholic solution of the aurichloride.Colourless octahedra of aurichlorjccpbenxnconine me1 ting at 179' separated. The amorphous base which accompanies japaconitine io Japanese aconite roots is therefore japbenzaconine. The amount is exceedingly small (about 1 gram from l l g kilos.) as compared with the quantity of benzaconine contained in the roots of Aconitum Napellus. The results of this investigation, which has occupied us for several years, seem to leave no room for doubt that the crystalline alkaloid (japaconitine) of Japanese aconite, though closely resembling aconitine, the crystalline alkaloid of A. Napellus, is chemically a distinct individual. The chief differences which we have established between them and their derivatives are summarised in the folIowing tables : 1.-Japaconitine and Aconitifie.Substance. Ja paconitine ..................... Aconitine ........................ Japaconitine hydrochloride,. . Aconitine hydrochloride ...... Japaconitine hydrobromide.. . Aconitine hydrobroniide ...... Japaconitine hydriodide ...... Aconitine hydriodide ......... Japnconitine aurichloride ... Aconitine aurichloride ......... Triacetyljapaconitine ......... Triace tylaconitine ............ Melting point. 204'2" 196-1 97' 149-150" 149" 172-173' 163" 207-208" 226" (a) 135'5' ( B ) 152" ( Y ) 176" 166-167 207" Specific rotation. + 20.25" in chloroforrr + 14 -6" in chloroform - 23 '8" in water - 30.9" in water - 30 .So in water Remarks. Prismatic needles Hexagonal prisms64 JAPACONITINE AND THE ALKACOIIM OF JAPANESE ACONITE. I1 .--Japbenxaconine crnd Renxnconine. Melting point. Substance. Specific rotation. Remarks. Japbenzaconine ................. Benzacoiiiiie .................... f 40*16" i i i alvohol + 4 '48" in alcohol ltcctnngular plates Uncrystrtllised 182-1 83" 125" JapSenzaconine hydrochlorid Renzaconine hydrochloride . . - 19'73" in water - 28.7" in water 205-217" 282" Japbenzaconine hydrobromidl Benzaconine hydrobromide.. Japbenzaconine aurichloride. Benzaconine aurichloride.. ... Aurichlor-japbenzaconine ..... Aurichlor-benzaconine ....... 228" 125-135" 178" 204" 0 c tahedra 3ectanplar prisms Japaconine and Aconine. Melting point. Substance. Specific rotation. Remarks. Japaconine ....................... Aconine ........................... 97-100" 132" -t 10.88" in water f23" in water Amorphous, very hygroscopic Amorphous, very hygroscopic Japaconine hydrobromide . . , 221" Uncry stallised Japaconine hydrochloride . . I Aconine hydrochloride.. ....... 175'5" - 7-71" in waterSEPARATION OF ISOMERIDES CONTAINED IN XYLIDINE. 65 Pyrojapaconitine and Pyraconitine. Substance. Py rqjapaconitine .............. Pyraconitine .................... Pyrojapaconitine hgdro- chloride Pyraconitine hydrochloride.. Pyrojapnconitine hydro- bromide Pyraconitine hydrobromide.. Pyrojapaconitine aurichlorid Pyraconitine aurichloride.. ... Pyrojapaconine ................ Pyraconine ....................... Melting point. i53--16a0 167'5" 175-176" 248 9 5 " 161" Specific rotation. - 85-89" in alcohol Inactive - 102'5" - 46'8" in water - 73'96" in water - 90.99' in water Remarks. Crystalline Uncrystallised Uncrystallised Uncrystallised The conclusions to be drawn from our results as to the composition and properties of japaconitine are not in agreement with those of Wright and his fellow-workers. Neither can we confirm the opinions which have been advanced by Blandelin, Liibbe, and by Freund and Beck, all of whom regard japaconitine as identical with aconitine. For the present, we reserve a discussion of the exact nature of the relationship between japaconitine and aconitine, as we are not yet in a position t o decide finally which formula to select for either alkaloid as most correctly expressing its composition and the composition of its derivatives, SCIENTIFIC DEPARTMENT, IMPEEIAL INSTITUTE, S . W.

ISSN:0368-1645    

DOI:10.1039/CT9007700045

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

SEPARATION OF ISOMERIDES CONTAINED IN XYLIDINE. 65 VL-A Method of Separation of the various Isomerides contained in ordinary co mmercia 1 Xy lid h e . * By W. R. HODGKINSON and LEONHARD LIMPACH. ORDINARY technical, or commercial, xylidine, obtained by the nitration and subsequent reduction of the coal tar xylene distilling between * This is a continuation of some work on xylidines and xylenols (compare Trans., 1892, 61, 420 ; 1893, 63, 104). VOL. LXXVLI. F66 HODGRINSON AND LIMPACH : A METEOD OF SEPARATION OF 136' and 142', contains, with the exception of the symmetrical 5-arnino-nz-xylene, all the possible isomerides from the three xylenes. The main constituents are the 4-amino-na-xylene and the 2-amino-p- xylene, which together make up about 70 per cent, of the total bases, In the present paper, an account is given of a process for effecting a complete separation of all the isomerides present in commercial xylidine, making use of the method aIready devised by one of the authors for the isolation of 4-amino-m-xylene as acetate, and of 2-amino-p-xylene as hydrochloride (Germ, pat., 39947, of Septembeic 19th, 1886; Eng.pat., 11822, 1886), and of 2-amino-rn-xylene by means of its formyl derivative (Ber., 1899, 32, 1008). 4- Amino-m-xylens. When acetic acid is added t o ordinary xylidine, the acetate of the 4-amino-rn-xylene is the only one to crystalliae out, The method we have worked out, and employed t o obtain the different xylenols, de- pends in the first instance on this fact. As an example, 300 gramv of commercially pure xylidine were treated with slightly more than the necessary amount of glacial" acetic acid to convert the 4-amino-rn-xylene into its acetate,? The crystallisa- tion of the acetate commenced a t once, and was practically completed after 24 hours standing.The crystals were separated in a centrifugal separator (a filter pump would be equally effective), and, after press- ing, were found to be almost pure 4-amino-m-xylene acetate. As a rule, the yield of the base by this method amounts to from 40 to 42 per cent. of the original xylidine. The acetate was hydrolysed with sodium hydroxide, and the base converted into the formyl derivative, which, after the first crgatal- lisation from dilute alcohol, melted a t 113.5'. 2 -A mino- p-x y Zene . The filtrate and mother liquors contain a considerable amount of the 2-amino-p-xylene 2 and smaller quantities of 3-amino-o-xyIene, 4-amino-o-xylene, and 2-amino-m-xylene.To this mixture, hydrogen chloride (ordinary strong solution) was added until the whole dissolved. On cooling, the 2-amino-p-xylene hydrochloride crystallised out, and after a couple of recrystallisations was obtained quite pure. * Glacial acid is not absolutely necessary ; 80 per cent. acid acts quite well, but the product takes a longer time to cryatallise. t This can be ascertained sufficiently nearly on a very sinall scale, '$ This is valuable for the production of pseudocumidine.THE VARIOUS ISOMERIDES CONTAINED IN XYLIDINE. 67 It may be remarked that the product obtained in the first crystal- lisation is sufficiently pure for conversion into pseudocumidine.Some of the product from the first crystallisation was made into the formyl derivative. This melted a t 116-117', aEter the first crystallisation from weak alcohol. As indicated by this method, about 30 per cent, of this isomeride is, as a rule, contained in ordinary xylidine. 2-Amino -m-xy Zene. The residue (filtrate) from the para-base now contains the two ortho- and the meta-isomerides. We find that the 2 -amino-m-xylene can be very completely separated in the following manner. The mother liquors are evaporated in a retort. After the excess of acid and water has distilled off, the contents of the retort become semi- solid. On now gently heating, the hydrochloride of 2-amino-m-xylenc sublimes in very beautiful, silky, needle-shaped crystals. One re- sublimation gave a perfectly pure product.From 300 grams of xylidine we have obtained 1OA6 grams of this salt, indicating the presence of 2.7 per cent. of this isomeride. Another method, adapted for larger operations, is to distil off about 20 per cent. of the contents of the retort by heating rapidly; the distillate then solidifies very quickly. It can then be converted into the formyl derivative, and easily be obtained perfectly pure by one cry stallisation. The formyl derivative of 2-amino-m-xylene crystallises in very beautiful, long needles which, when slowly heated in the usual way, melt at 164O, but when rapidly heated, melt only at 176-171'. It is completely hydrolysed after boiling for 6 hours with alcoholic potassium hydroxide, The acetyl derivative melts a t 177", and also crystallises in long needles.The base distils completely a t 216' under 735 mm. pressure (therm. in vapour), and has a sp. gr. 0.980 at 15'. From this isomeride, we have obtained, by diazotisation, the m-2- xylenol." It crystallises from water, in which it is somewhat soluble, in long, hard crystals, and from dilute alcohol in long prisms. It melts at 47' and boils at 199.6' (therm. in vapour) under 738 mm. pressure. * We have prepared a number of derivatives from this xylenol, which we hope to describe, with others, later.68 SEPARATION OF ISOMERIDES CONTAINED IN XYLIDINE. 3-Amino-o-xylena. The black residue in the retort, from which the 2-amino-m-xylehe hydrochloride had been sublimed, consisted of the hydrochlorides * of the two ortho-bases.? It was dissolved in water, and the bases, set free by the addition of excess of sodium hydroxide, were separated from the alkaline liquid, distilled in steam,$ and then converted into their formyl derivatives.This is particularly easily accomplished by the simple addition of the necessary amount of formic acid, of 28 per cent. strength, and heating on a water-bath. The two formyl compounds were now separated by taking ad- vantage of a slight difference in their rate or facility of crystallising. After standing for a few days, the mixture became semi-solid; the liquid portion was then pressed out, and the solid portion recrystal- lised. They were hydrolysed by alcoholic sodium hydroxide, and the base converted into the acetyl derivative, which melted a t 132'. This base, therefore, is 3-amino-o-xylene, and the amount contained in xylidine amounts roughly t o 9-11 per cent.The first batch of crystals melted a t 100-102°. 4-Amino-o-xylene. The mother liquor pressed from the formyl derivative of 3-amino-o- xylene consists for the most part of that of 4-amino-o-xylene, with small quantities of the other bases which have escaped separation. It is very difficult to induce this formyl derivative to crystallise. Cooling with a freezing mixture to -20' for some time was without result. It was therefore hydrolysed, and the base separated. This dis- tilled over completely at 222' (therm. in vapour), and after standing for 3 or 4 months during the winter, formed large, monoclinic crystals, which melted at 48'. A formyl derivative prepared from them was induced to crystallise by considerable cooling and agitation, and the base obtained from this crystallised material by hydrolysis melted at 5 2 O . There is therefore no doubt it is the 4-amino-o-xylene. We have prepared considerable quantities of the xylenols corre- sponding to these xylidines, and will shortly give an account of some of their derivatives. WOOLWICH AND ERLANGEN. * For some purposes these may be used without further purification. -t About 20 to 25 per cent. of these isomerides is contained in ordinary xylidine. $ These bases also distil alone without decomposition,

ISSN:0368-1645    

DOI:10.1039/CT9007700065

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

OXIDATION OF ORGANIC ACIDS 1N PRESENCE OF IKON. 69 VIL-The Oxidation of Organic Acids in Pyesence of Ferrous Iron, Part I. By HENRY J. HORSTMAN FENTON, M.A., F.R.S., and H. 0. JONES, B.A., B.Sc. THE oxidation of various organic substances by means of hydrogen dioxide and other agents in presence of small quantities of iron salts, has formed the subject of a considerable number of communications to the Society and elsewhere (compare Fenton, Chem. News., 1876, 33, 190; 1881, 43, 110; Trans., 1894, 65, 899; 1896, 69, 546; Proc., 1898, 14, 119; B d . Assoc. Reports, 1895, 1898, 1899; Fenton and Jackson, Trans., 1899, 75, 1 ; Cross and Bevan, Trans., 1898, 73, 463; 1899, 75, 747; Morrell and Crofts, Trans., 1899, 75, 786; Martinon, Bull. Xoc. Chim., 1885, [ii], 23, 196). The present paper deals with a continuation of this investigation, which is being carried out by the authors with a view of arriving at further general conclusions as to the nature of the reaction, the subjects selected for examination being various acids of typical con- stitution.Hydrogen dioxide has been employed as the oxidising agent in quantities corresponding to one atom of oxygen, or less, per molecule of acid, and the experiments have been carried out at low tempera- tures (0' to 15'). Larger proportions of oxygen and higher tempera- tures will probably give rise to interesting modifications in the results, and these will be studied on a future occasion. The iron, which is always used in the ferrous condition, is generally added as a salt of the acid operated upon, but in some cases ferrous sulphate or acetate is employed.The following is a brief outline of the method employed in carrying out the initial experiments : I. The acid (1 mol.) was dissolved in, or in some cases mixed with, a small quantity of water, cooled by ice, and hydrogen dioxide was added in proportion corresponding to about 11. The experiment was repeated under exactly similar conditions, but, with the previous addition of ferrous su1phat.e solution corre- sponding to Q at. of iron, the dioxide being added in quantity corre- sponding to about & at. of oxygen in excess of that required to oxidise the iron. The mixtures were kept in ice and tested for free hydrogen dioxide after five minutes and again after thirty minutes, chromic acid or titanic aoid being used for this purpose.With the following acids, strongly marked indications of free at. of oxygen.70 FENTON AND JONES: THE OXIDATION OF hydrogen dioxide were shown in both series of experiments even after 30 minutes ; acetic, monocliloracetic, oxalic, malonic, szcccinic, dibromo- mccinic, fumavic, maleic. Considering the small proportion of dioxide employed, these acids may therefore be considered, at any rate for the present purpose, as inactive towards the reagent. I n the case of formic, glycollic, lactic, glyceric, tartronic, P-hydroxy- butyric, tartaric, wzalic, saccharic, mucic, pyvomucic, cmtylenedicarb- oxylic, acetonedicc~rboxy~ic, dihydroxytartaric, dihydroxymaleic, benxoic, and picric acids, however, a rapid (generally almost instantaneous) oxidation takes place in experiment 11, that is, in the presence of the ferrous salt, all tracos of the dioxide disappearing within five minutes, whereas in experiment I, where iron is absent, strongly marked indications of the dioxide remain after 30 minutes.Citric and P-iodopropionic acids behave similarly, but the oxidation in presence of iron is less rapid. Pyruvic acid alone appears to be immediately attacked by hydrogen dioxide, either with or without the presence of iron. I n the case of nearly all of the above acids which are 'active' towards the reagent, the products appear to be of great interest, new substances being obtained or oxidations effected which are not possible by other means. The systematic study of these changes, although in some cases direct and simple, yet often, in others, presents peculiar difficulties owing to the unstable nature of the products." It is evi- dent, therefore, that the complete investigation of these products, together with those of several other acids which suggest themselves, will occupy a very considerable time, and it is considered desirable in the present communication t o give an account of results which have been obtained up to the present date.Glycollic Acid. The pure crystallised acid (1 mol.) was dissolved in water, mixed with a small quantity of ferrous acetate (4 at. or less of Fe), the mixture cooled by ice, and hydrogen dioxide (1 at. of oxygen) slowly added, On addition of phenylhydrazine acetate (1 mol.), a dark coloured precipitate is immediately formed, which soon turns orange- red and increases considerably in quantity on standing.This preci- pitate was washed, dried, and purified first by crystallisation from a mixture of ether and light petroleum, and then from a small quantity of hot ethyl acetate (a small quantity of light yellow, insoluble matter remains which appears t o be ferrous oxalate). This product crystnllises in orange-yellow needles which melt and decompose at * Compare, for example, the identification and isolation of dihydroxymaleic acid (Trans., 1894, 65, 899 et seq.).ORGANIC ACIDS IN PRESENCE OF FERROUS IRON. PART I, 71 137", and corresponds entirely with the hydrazone of glyoxylic acid, CH(N,H*C,H,)*CO,H, which was prepared by Elbers from calcium glyoxylate (Annabn, l8S5, 22'7, 341).0.2120 gave 31.7 C.C. nitrogen at 18" and 752 rum. N = 17.30. C,H,0,N2 requires N = 1'7.07 per cent, The yield of crude hydrazone is nearly equal to the weight of acid used. Lactic Acid. When this acid is oxidised in a similar manner, a very considerable evolution of heat occurs, and, in order to obtain the best results, it is necessary to add the oxidising agent very slowly, and to take especial care to keep the mixture cold; i t was found advisable also to use only about one-half the calculated quantity of oxygen. The reason that these precautions are necessary is probably to be found in the great instability of the product towards hydrogen dioxide (see pyruvic acid), On adding phenylhydrazine acetate (1 mol. in proportion to the dioxide employed), a greenish or yellow precipitate of pyruvic acid hydrazone, CH,*C(N,H* C6H,)*C0,H, is obtained, whicb, when washed with a little cold alcohol and recrystallised from hot alcohol, separates in the form of long, pale yellow, transparent needles, which, when quickly heated, melt at 192'.0.2102 gave 29.1 C.C. nitrogen at 22" and 758.3 mm. C,H,,02N2 requires N = 15.73 per cent. N = 16.03. I'ccrtronic Acid, This was prepared from dihydroxytartaric acid in the manner previously described by one of the authors (Trans., 1898,'73, 72). The aqueous solution was mixed with ferrous sulphate (a at. Fe) and hydrogen dioxide corresponding to rather less than 1 at. of oxygen slowly added. On the addition of phenylhydrazine hydrochloride (1 mol. in proportion to the oxygen employed) a bulky, brownish- yellow precipitateof mesoxalicacid hydrazone, C(C0,H),:N,H*C6H5, was obtained, This, when recrystallised from hot alcohol, was obtained in long, transparent, pale yellow prisms, which melted at 170-1 71" when quickly heated." The yield of hydrazone is nearly equal to the weight of acid oxidised.0.2342 gave 27.5 C.C. nitrogen at 20.5" and 753 mm. C,H,O,N, requires N = 13.46 per cent. * Elbers (Zoc. cit., 355) gives the melting point of this hydrazone as 158-164", but Clemm (Bcr., 1898, 31, 1451) fouud that, if quickly heated, it melts a t 174". N = 13.57*72 FENTON AND JONES: THE OXIDATION OF The direct oxidation of tartronic to mesoxalic acid has not hitherto been effected, although OF course the converse change is well known. It is possible that the process may be found advantageous for the preparation of mesoxalic acid, especially since tartronic acid is so easily obtained by the method above mentioned.Glyceric Acid. The pure acid, free from glycerol, was oxidised in the manner above described, the iron being added in the form of ferrous glycerate. The action is immediate, and but little heat is evolved. One mol. of hydrogen dioxide appears to be used up almost quantitatively since, on the addition of any further quantity, but not before, the free dioxide can be detected in the mixture. The resulting solution, when made alkaline with caustic soda, gives a beautiful wiolet colour, which is much intensified on the addition of ferric chloride. Treated with a mixture of alcohol and ether, the iron is nearly wholly precipitated, and the solution, on evaporation, leaves a thick syrup, which, when made alkaline, gives again the violet colour with ferric chloride.The substance, purified in this way, reduces ammoniacal silver nitrate, very slowly restores the colour to a rosaniline salt bleached by sulphurous acid, and gives precipitates with lead, barium, and silver salts. On adding phenylhydrazine acetate (1 mol.), a bulky, orange pre- cipitate is at once produced. The yield of crude substance (air- dried) is about equal to the weight of acid oxidised. It was purified by washing with a little cold benzene and recrystallising from hot benzene, from which it separates in aggregates of short prisms which melt at 203-205O. These, on analysis, gave N= 19.5 per cent, The specimen prepared in this way, however, mas found to contain a trace of iron, so that for further analysis i t was purified by the method mentioned below.On heating the substance with a strong solution of sodium carbon- ate, i t dissolves t o a yellow solution which dyes wool, &c., a bright lemon-yellow colour. Beautiful, yellow glistening plates or needles separate as the solution cools, and these, when dried a t looo, melted at 235-237O. On decomposing this sodium compound with hot dilute hydrochloric acid, the original substance separates as an orange precipitate which, when recrystallised from hot benzene, melts a t 2074 Dried at 1000 it gave, on analysis, the following results : 0.1201 gave 0.2817 CO, and 0,0532 H,O. 0.1295 ,, 22.5 C.C. nitrogen at 19O and 760 mm.N = 20.37. C= 63.96 ; H =4.92. C,,HI4N4O2 requires C = 63-82 ; H = 4.96 ; N = 19.85 per cent,OR(3ANIC ACIDS IN PRESENCE OF FERROUS IRON. PART 3. 73 Nastvogel (Annulen, 1888, M8, 8 5 ) obtained a substance of this composition by acting upon dibromopyruvic acid (1 mol.) with phenyl- hydrazine (2 mols.). It formed orange crystals which melted a t 201-203°, and its properties exactly corresponded to those of the substance obtained in the present case. The sodium salt was obtained in a similar way, and melted at 231". From its mode of formation and properties, he assigned to it the formula and termed i t the osazone of glyoxal-carboxylic acid. Lxter, W. Will (Bey., 1891, 24, 400) obtained this osazone in an entirely different way. H e treated a solution of collodion-wool in alcoholic ether with a 10 per cent.solution of caustic soda for about 24 hours a t ZOO, and obtained an acid which had reducing properties, and, with phenylhydrazine acetate, gave an osazone, melting a t 205O, identical with the above. Analysis of the calcium, strontium, and other salts of the acid indicated the formula C,H,O, for t h e latter, so that it must be either hydroxypyruvic acid, CH,(OH)*CO* CO,H, or the semi-aldehyde of tartronic acid, CHO*CH(OH)*CO,H, either of which would, of course, give the osazone in question. From the facts that the acid is not oxidised by bromine, and that it is not altered by heating with lime water or baryta water, Will concluded that i t is hydroxypyruvic acid. By acting upon an alcoholic solution of the osazone with hydrogen chloride, he obtained a substance crystallising in reddish-yellow needles and melting a t 1 4 9 O , which at first was considered to be the ethyl ester, but later (Zoc.cit., 3831) was shown to be a pyrazolone CO *NPh derivative, NHPh*N:C<CH:& , It is, in fact, identical with the phenylhydrazine ketophenylpyrazolone which Knorr obtained by heat- ing the osazone with acetic anhydride (Bey., 1888, 21, 1201). In order further to confirm t h e identity of the osazone a t present under consideration with that of Nastvogel and Will, it was converted into the pyrazolone by the method employed by the latter. The alcoholic solution of the osazone was saturated with dry hydrogen chloride, allowed t o stand for some time, evaporated to dryness on a water-bath dissolved in dilute soda solution, filtered, and acidified with dilute sulphuric acid.The precipitated substance, on recrystallisation from alcohol, was obtained in beautiful orange needles melting at 1 4 8 O . From these results, it is evident t h a t the oxidation product of glyceric acid may be either ( I ) the semi-aldehyde of tartronic acid, (2) hydroxypgruvic acid, or (3) the semi-aldehyde of mesoxalic acid. In order to throw further light upon the question, a solution of the oxidised product, prepared from a known weight of glyceric acid, was7s FENTON AND JONES: THE OXIDATION OF mixed with a quantity of bromine corresponding to more than 2 atomic proportions in excess of that required to oxidise the iron present. After standing for 24 hours at the ordinary temperature, with repeated shaking, the’free bromine was removed by sulphurous acid, and sodium acetate and phenylhydrazine acetate added.The resulting precipitate was found to be identical in every respect with that originally obtained, and the yield was but little diminished. Further experiments were made, using a considerably larger excess of bromine, and also allowing the mixture to stand for over a fortnight, but in all cases the result- ing liquid gave strong evidence of the presence of the original sub- stance, an intense violet d o u r being obtained on testing the mixture with ferric chloride and alkali after removal of the free bromine. It appears therefore that the substance is incapable of oxidation by bromine, in presence of water, at the ordinary temperature. Heated with bromine on a water-bath for several hours, the substance is slowly oxidised; the resulting product has not been fully examined, but appears to be neither tartronic nor mesoxalic acid.With excessof freshly precipitated silver oxide, again, very littleoxida- tionresults at theordinary temperature, the mixture, even afterstanding for some days and subsequent removal of the silver, showinga strong reaction with ferric chloride and giving the same osazone with phenyl- hydrazine. When heated for some time a t about 40°, the oxidation proceeds more quickly, but the product, after removal of silver, appears to be only oxalic acid, A copious precipitate of phenyl- hydrazine oxalate is obtained on adding the acetate, whereas the hydrochloride gives only a slight precipitate resembling the original osazone.If the original solution (containing iron) is mixed with a large excess of baryta water, the violet precipitate which is formed remains permanent, even on heating f o r two or three hours on a water-bath. These facts afford fairly strong evidence that the oxidation product is not aldehydic, and consequently that the acid under consideration is hydroxypyruuic acid. The absence of the other two acids i n minute quantity is of course not absolutely certain, since small traces of tartronic or mesoxalic acids might not be detected in the products mentioned. The properties of the substance coincide in fact very closely with those of the acid obtained by Will from collodion. I n Will’s papers, however, no mention is made of the remarkable colour reaction with ferric chloride, which is certainly the most striking property of the present substance.This colour reaction is very similar t o that pro- duced by dihydroxymaleic acid, and the authors were at first inclined to believe that the product might be dihydroxyacrylic acid, CH(OE):C(OH)*CO,H, which would be formed from glyceric acid byORGANIC ACIDS IN PRESENCE OF FERROUS IRON. PART I. 75 removal of two non-hydroxylic hydrogen atoms (compare Proc., 1898, 14, 119). It is of course possible that this may represent the initial reaction aud that the product afterwards undergoes tautomeric change, becoming hydroxypyruvic acid. Malic Acid. On addition of hydrogen dioxide to a solution of this acid contain- ing a little ferrous salt, the colour of the liquid immediately becomes deep red, much heat is evolved, and carbon dioxide is given off.If, however, the solution is carefully cooled by a freezing mixture and the hydrogen dioxide added very slowly, the action proceeds without any appreciable evolution of gas. I n the following experiments, the acid was dissolved in very little water and the required quantity of iron ( ferrurn redacturn about Q at.) dissolved in the liquid." The hydro- gen dioxide was used in quantity representing rather less than 1 at. of oxygen. On adding phenylhydrazine acetate (1 mol. in proportion to the oxygen employed) to the resulting liquid, a very copious, bright, orange- yellow precipitate is formed immediately. The yield of this precipitate (air dried) considerably exceeds the weight of acid oxidised.This substance dissolves sparingly in most cold solvents, but fairly easily in hot alcohol, benzene, or chloroform. It may he crystallised from any of these solvents, but the last appears to give the best result, It is thus obtained in brilliant, long, orange-yellow prisms belonging to the prismatic system, and melting at 217-219°. Distinct specimens prepared on different occasions, and all melting within the above range of temperature, gave the following results on analysis : 1. C=63*30. H=5.17. N = 20.10. 11. C=63.35. H = 5-47, N = 20.21. 111. C = 62.S". H = 4.95. N = 20.07. IV. C=63*31. H = 5.12. N = 20.26. Assuming that the product is derived from an acid containing four carbon atoms these numbers correspond best with those required for a derivative of dihydroxytartaric acid or of dihydroxymaleic (or isomeric) acid.C,H,O, + 3N,H,C,H5 - 3H,O requires C = 63.46 ; H = 4-80 ; N = 20.19 It will be shown in the following communication (p. Sl) that this sub- stance is the result of further action of the oxidising agent upon the product which is first formed. It was evident, in fact, that the action * It is now found, however, that the addition of ferrous sulphate or acetate answers equally well. C,H,O, + 3N,H3C6H, - 3H20 ,, C = 63.15 ; H = 5.86 ; N = 20.0976 OXIDATION OF ORGANIC ACIDS IN PRESENCE OF IRON. of phenylhydrazine does not in this case afford direct evidence as t o the nature of the reaction under investigation, and the problem was therefore attacked in a different manner.The experiments which were made resulted in the isolation of oxalucetic m i d , and from the special interest which attaches to this substance, the authors have thought it advisable to give an account of this part of the investigation in a separate paper. The following acids have been only superficially examined : Mucic and Xuccharic Acids, when oxidised in the above manner, yield products which give brown precipitates with phenylhydrazine acetate, and when made alkaline with caustic rjoda give deep red- violet colours, which are intensified by the addition of ferric chloride. If the action is analogous to that of tartaric acid, it is evident that these products may be of much interest. They are very unstable, however, and it will doubtless be a matter of some difficulty to isolate them. Pyromucic Acid turns an intense but transient violet colour, and pic& acid gives an intense green colour ; both products react with phen ylhydrazine. Acetylernedicarboxylic Acid is immediately attacked in presence of iron-the solution becoming dark brown. The solution now gives an immediate precipitate with phenylhydrazine, which is quite different from the precipitate slowly formed with the original acid. Acetonedicudoxylic Acid.-This is similarly oxidised when iron is present, the change taking place rather more slowly than in the pre- ceding cases. The product gives an intense purple colour with alkalis, which is intensified on addition of ferric chloride. This colour is quite distinct from that given by the original acid with ferric chloride, which is destroyed by alkalis. Belzxoic Acid is immediately oxidised, the result giving a violet colour with ferric salts, presumably due to the formation of salicylic acid. It is the intention of the authors to make a complete study of these products, and to extend the observations to a large number of other acids. It is evident that several general conclusions might already be suggested by the foregoing results, but it is considered preferable to defer such considerations until the investigation is completed. Part of the expenditure which has been incurred in carrying out this research has been defrayed by funds kindly placed at the dis- posal of one of the authors by the Government Grant Committee of the Royal Society,

ISSN:0368-1645    

DOI:10.1039/CT9007700069

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

FENTON AND JONES : OXALACETIC ACID. 77 VII1.- Oxalacetic Acid. By HENRY J. HORSTMAN FENTON, M. A., F.R.S., and H. 0. JONES, B.A., B.Sc, IN the preceding communication, it is shown that malic acid is very energetically oxidised by hydrogen dioxide in presence of ferrous iron. The oxidation is attended with considerable evolution of heat, and unless special precautions are taken to keep the temperature low, carbon dioxide is evolved and pyruvic acid is Found in the liquid. On shaking up the original oxidised mixture with ether, scarcely anything could be extracted, and the addition of salt, sodium sulphate, &C., did not much improve the result. I n the initial experiments, which were made in studying the oxidation product of tartaric acid (Trans., 1894, 65, 901), it was shown that the addition of strong sulphuric acid to the mixture greatly increased the yield on extraction with ether, and in the present instance the same is found to be the case.By adding slowly about one-tenth its volume of strong sulphuric acid to the oxidised mixture, with careful cooling, and repeatedly shak- ing with ether, a considerable quantity of substance can be extracted. I n the first experiments, no special care was taken to keep the mix- ture well cooled during oxidation and during the addition of sulphuric acid, I n this case, the ether extract, on evaporation, gave a syrupy residue with a small quantity of a white, crystalline substance. The syrupy portion, when dissolved in water, gave immediately a white precipitate with phenylhydrazine acetate which, when recrystallised from alcohol, melted at 192O, and had all the characters of pywvic acid hydrazone.0*1494 gave 20.9 C.C. nitrogen a t 25' and 749.4 mm. C,H,,,O,N, requires N = 15.73 per cent. It was afterwards found that if great precautions are taken to pre- vent rise of temperature during the operations referred to, the ether ex- tract, when concentrated to a small bulk, deposits the white, crystalline substance in considerable quantity, and, on further evaporation, usually solidifies to a white mass. The method of proceeding is as follows : Malic acid (1 mol.) is dis- solved in the least possible quantity of water, and zt ferrous salt is added in quantity corresponding to about 4 at., or less, of iron. The nature of the ferrous salt is immaterial, and the sulphate, acetate, or malate may be employed.The mixture is cooled by ice and salt until N r- 15.85.78 FENTON AND JONES : OXALACETIC ACID, it begins to freeze, and hydrogen dioxide (20-volume strength"), cooled i n a similar way, is added in very small quantities a t a time with care- ful mixing, in proportion amounting to nearly 1 at, of oxygen. The liquid assumes an intense blood-red colour as soon as the first few drops of the dioxide have been added, The solution is now mixed with about one-tenth of its volume of strong sulphuric acid, great precautions being taken, as before, to prevent the temperature from rising more than a few degrees, and is repeatedly extracted with ether. The ethereal solution gives an intense blood-red colour with ferric chloride, so that the progress of the extraction, is easily tested ; even after 26 extractions, a further yield may be obtained.The ethereal extract is concentrated to a small bulk and the residual solution, on cooling, begins t o deposit the white, crystalline acid, the quantity being much increased on stirring, It is kept in a desiccator, partially exhausted, until the whole has solidified, and is then quickly washed three or four times with cold water, draining well each time with the aid of s pump. The yield of pure substance is about 22 per cent. of the acid oxidised. Properties.-The subst-ance separates from its solution in ether, acetone, or water, in white, crystalline aggregates which dissolve vety slowly in cold water and easily, but with decomposition, in hot water.It is rather more soluble in ether, easily soluble in alcohol or acetone, and scarcely soluble in chloroform or benzene. It crystallises from a mixture of acetone and benzene in blade-like crystals belonging to the prismatic system, and has a great tendency to form close aggregates. The aqueous solution gives an intense blood- red colour with ferric salts, which is scarcely affected by dilute mineral acids. Heated in a capillary tube, it melts with sudden decomposition a t 176-180". Analysis of the substance dried in a vacuum desiccator gave the following result : 0.1766 gave 0,2361 CO, and 0.0488 H20. C = 36.46 ; H = 3.07. C,H,O, requires C = 36.36 ; H = 3.03 per cent. Owing to its sparingly solubility in appropriate solvents, and to its in- stability a t high temperatures, the molecular weight could not well be determined by the freezing or boiling point methods.It will be shown, however, that the methyl ester dissolves easily in acetic acid, so that the value is easily determined in that case. Titration with Alkalis.--The acid was dissolved in cold water and * In later experiments, the dioxide has been allowed partially to freeze until the strength of the liquid portion is about doubled, and this procedure is found to be very advantageous, owing to the smaller quantity of water introduced.FENTON AND JONES : OXALACETIC ACID. 79 titrated with pure caustic soda solution containing 0.01507 Na per c.c., prepared from metallic sodium. Phenolphthalein was used as indicator, and special precautions were taken to exclude carbon dioxide.05188 required 11.85 C.C. soda solution for neutralisation, the calculated amount for a dibasic acid of the formula C,H,05 being 11.99 C.C. After boiling the aqueous solution for a few minutes, carbon dioxide is evolved and the neutralising power is nearly halved, thus 0.6097 gram of the substance was heated for 5 minutes and then required 8.2 C.C. of the alkali, the calculated amount being 7.0 C.C. After heating for half an hour, a nearly similar result was obtained. On acidifying the resulting solution with acetic acid and adding phenylhydrazine acet- ate, a nearly white, crystalline precipitate was obtained which melted at 192O, and had all the other characters of pyvzcvic acid hydmxone. Barium Salt.-A solution of the acid was exactly neutralised with pure soda and an excess of barium chloride added.The resulting white precipitate was well washed and dried in a vacuum desiccator. C,H,O,Ba + 2H20 requires Ba = 45.2 1 per cent. 0.4780 gave 0.3677 BaSO,. This salt, when treated with ferric chloride, gives a deep, brick-red colour. Calcium, strontium, lead, and silver salts, similarly, give white pre- cipitates, the silver salt being quickly reduced on heating. Methyl ester, C,H20( CO,CH,),.-This was obtained by dissolving the acid in methyl alcohol, cooling the solution by ice, and partially saturating with dry hydrogen chloride. After the mixture had re- mained for about 24 hours, it was allowed to evaporate over solid potash and sulphuric acid, and the resulting solid crystalline mass well washed with cold water, in which i t is scarcely soluble, then with a little cold methyl alcohol, and was finally recrystallised from hot methyl alcohol.It is thus obtained in beautiful, transparent, oblique prisms which melt at 77". The following results were obtained on analysing the substance dried in a vacuum desiccator : C = 44.89 ; H = 4.75. Ba = 45-23, I. 0*1418 gave 0,2334 CO, and 0.0607 H,O. 11. 0.1571 ,, 0.2598 GO, ,, 0.0712 H,O. C =45*10 j H=5.03. C,H,05 requires C = 45.00 j H = 5.00 per cent. Three molecular weight determinations by the freezing point method in the same quantity of acetic acid gave the following numbers, the calculated molecular weight being 160 :80 FENTON AND JONES : OXALACETIC ACID, Solvent. Substance. Depression.Mol. weight. I. 13-90 0.1290 0.243 148.9 11. - 0.2908 0.532 153.3 111. - 0.4038 0.753 150.5 The alcoholic solution of this ester gives the deep red colour with ferric chloride. The analysis, molecular weight, melting point, and other properties show that this substance is identical in every way with methyl oml- acetate, which mas obtained Ly Wislicenus from the action of sodium on a mixture of oxalic and acetic esters, the melting point of which is given as 74-76'. Action oj Phenyllydraxine 012 the Acid. When the acid (1 mol.) is dissolved in a little cold water and mixed with phenylhydrazine acetate (1 mol.), the solution at first remains clear, but after standing for some minutes it gives, on stirring, a pale, straw-coloured, crystalline precipitate of the hydrazone of oxalacetic acid, CO,H* CH,= C(N,H*C,H,)*CO,H, which is seen under the micro- scope to consist of transparent, oblique prisms.This product is nearly pure, giving, on analysis, N = 12.14 per cent. After recrystallisation from cold, dry ether, however, the crystals are lustrous and perfectly colourless. After drying in a vacuum desiccator, they yielded the following results on analysis : 0.1232 gave 0.2422 CO, and 0.0499 H,O. C = 53.61 ; H = 4.50. 0.1841 ,, 19.3 C.C. nitrogen at 17' and 767 mm. N = 12.49. C,,H,,O,N, requires C = 54.05 ; H = 4.50 ; N = 12.61 per cent, The pure substance, when slowly heated, turns yellow, and without melting shows signs of decomposition at 95-100' ; if suddenly heated to a little above looo, the decomposition is violent. The yellow product of decomposition, however, melts at 182-183O.This hydrazone dissolves in concentrated d p h u r i c acid with a deep red colour, and on addition of ferric chloride to the solution a fine purple colour is produced. It resembles in this respect the hydrazone of the methyl ester. Wislicenus (Ber., 1886, 19, 3225) and Bnchner (Ber., 1889, 22, 2929) have shown that the hydrazones of ethyl and methyl oxal- acetates when acted on by dilute alkalis or acids, lose the re- spective alcohol and water, giving rise to a sparingly soluble acid having the formula CloH,O,N,, which begins to decompose without melting at 240-250°, and melts at 263'. This substance is shown t o be 1-phenyl-5-pyrazolone-3-monocarboxylic acid. This acid gave aFENTON AN11 JONES : OXALACETIC ACID.81 red colour with nitric acid, a scarlet with nitrous acid, and a dark blue with ferric chloride in hot aqueous solution. It was considered probable therefore that the hydrazone at present under consideration might behave in a similar may, and such is found to be the case. On heating the original pale yellow substance with dilute sulphuric acid, it is changed in a few minutes into a voluminous, white, crystalline magma, which dissolves sparingly in boiling water, and separates on cooling in beaut,iful, transparent needles. On heat- ing, these turned yellow and showed signs of decomposition at about 343O, and completely melted a t about 260". For analysis, the sub- stance mas dried at 100'. 0.1804 gave 21.2 C.C. nitrogen at 18.5" and 764 mm. C,oH,O,N, requires N = 13.72 per cent.The colour reactions of this product coincided exactly with those mentioned above, and in fact it is identical in every respect with the acid obtained by these authors. N = 13.SS. Action of Phenglhgdyaxine on the Methyl Ester. The ester (1 mol.) was dissolved in methyl alcohol and mixed with phenylhydrazine acetate (1 rnol.) ; the clear mixture, on standing in a desiccator over potash and sulphuric acid, soon deposited brilliant, colourless, transparent plates, which, when recrystallised from methyl alcohol, melted at 11 7". Buchner (Zoc. cit.), by the action of phenylhydrazine on methyl acetylenedicarboxylate, obtained the hydrazone of methyl oxalacetate : The product which lie obtained melted a t l l r S O , and the properties correspond exactly with those of the compJund obtained in the present instance.Oxidution OJ the Acid in preseizce of Iron. It was pointed out in the preceding communication (p. 75) that the product obtained by oxidising malic acid in presence of iron gave, with phenylhydrazine acetate, a, bright orange precipitate which crystallised from hot chloroform in prisms, and melted at 217-219'. The composition of this compound does not correspond with that of a direct derivative of oxalacetic acid, but of a more oxidised product. It appeared possible that this was the result of oxidation of a neighbouring group by the phenylhydrazine, but such does not appear to be the case, since no such substance can be obtained by the action VOL. LXXVII. G82 FENTON AND JONES : OXALACETIC ACID, of excess of the reagent on pure oxalacetic acid.Probably, there- fore, the oxidation is due to the hydrogen dioxide, a portion of the oxalacetic acid being further oxidised. Although only the calculated quantity of oxygen, or less, was added, it is of course possible that the product may be attacked as readily as the malic acid. In order t o test this hypothesis, pure oxalacetic acid (1 rnol.) was mixed with a little ferrous sulphate, and hydrogen dioxide (1 mol.) added under the conditions previously mentioned. On now adding phenylhydrazine acetate (1 rnol.), an o~ange precipitate wits obtained :exactly similar t o that orginally obtained from the malic acid oxidation, which, when recrystallised from chloroform, melted at 2 19'. Heated with sodium carbonate solution, it gave a crystalline sodium salt, and in fact showed exact similarity in every respect. The orange compound obtained from malic acid on different occa- sions was remarkably constant in composition and melting point, whereas a t firfit sight it might be supposed, on the above explanation, that it should be mixed with variable quantities of the hydrazone of oxalacetic acid.The latter compound, however, does not begin t o separate for several minutes, or in dilute solutions for over half an hour, whereas the orange compound comes down immediately ; the hydrazone, moreover, cannot be recrystallised from hot solvents, and would consequently be easily separated by the treatment described, The nature of this further oxidation product has yet to be in- vestigated.It gives a brownish-violet colour with ferric salts in alkaline solution, and the authors are inclined to conjecture that it may be the isomeric form of dihydroxymaleic acid, namely, CO,H* CH(OH)*CO*CO,H. Oxidation of the Acid by Bromine. When the acid (1 mol.) is mixed with glacial acetic acid and treated with dry bromine (1 mol.), the colour of the latter quickly disappears, and, after a short time, fumes of hydrogen bromide are evolved, A similar result is obtained by using water in place of acetic acid. The product in either case, when mixed with excess of caustic soda, gives an intense violet with ferric chloride, exactly resembling that produced by dihydroxymaleic acid with the same reagents. The authors have reasons, however, for thinking that this product is isomeric and not identical with the latter acid, and very probably it is identical with the product obtained in the previous experiment by oxidation with hydrogen dioxide.A further study of this reaction is in progress. From the foregoing results, it is evident that the oxidation product of maleic acid described above is free oxalacetic acid. Whether thisDETERMINATION OF THE CONSTITUTION OF FATTY ACIDS, 83 acid is to be regarded as C0,H*CO*CH2*C0,H, or as the tautomeric hydroxyfumaric acid, CO,H* C(OH):CH* CO,H, is, of course, a problem gimilar to the much discussed question of the constitution of ethyl acetoacetate. Either formula would equally well explain its forma- tion in the present case, and the reaction with phenylhydrazine, although lending support to the ketonic formula, is of course not oonclusiye. Nef (Armalert, 1893, 276, 230) by the hydrolysis of ethyl ethoxy- fnmarate, obtained an acid corresponding approximately in composi- tion to that required for the formula C,H,O,; it melted at 172O, gave a dark red colour with ferric chloride, and when treated with phenyl- hydrazine hydrochloride, gave the phenylpyrazolonecarboxylic acid above mentioned, This acid appears to be hydroxyfumaric acid, but since it was not obtained in a pure state a strict comparison with the present acid cannot be made ; the two acids may be identical or may represent the tautomeric (desmotropic) forms. Michael and Bucher (Bey., 1895, 28, 2511; 1896, 29, 1792) state t h a t oxalacetic acid is obtained by the action of water on acetoxy- maleic anhydride, and by acting with hydrochloric acid in the cold upon ethyl oxalacetate, unsymmetrical ethyl diethoxysuccinate, &c. There are only the bare statements, however; no details, analyses, or description of the acid are given. Nany interesting reactions of the acid suggest themselves, and these the authors hope shortly to investigate,

ISSN:0368-1645    

DOI:10.1039/CT9007700077

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

DETERMINATION OF THE CONSTITUTION OF FATTY ACIDS, 83 IX.-Determination of the Constitution of Fatty Acids. Part 11. By ARTHUR WILLIAM CROSSLEY and HENRY RONDEL LE SUEUR. IN the first part of this research (Trans., 1899, 75, 163), it was stated that among the acids then examined none contained alkyl groups in the a-position, and a s in such a case a new point of con- siderable interest is raised, we decided to prepare an acid of this type and submit it to the process there described, The acid selected was ethyl- isopropylacetic acid [a-isopropylbutyric acid], C,H,*CH(C,H,)*CO,H, which we have succeeded in preparing in large quantities from ethyl malonate. As the preparation is attended with many difficulties, we give full details of our experiments. Ethyl cyanoacetate has recently been used in synthetical work in- stead of ethyl malonate, with marked success ; we have also prepared ethylisopropylacetic acid from this substance a8 a starting point, but G 284 CROSSLEY AND LE SUEUR: DETERMINATION OF THE the method is not to be recommended, as the yield of pure acid is not nearly so good as when ethyl malonate is employed.Following the usual course of procedure when two alkyl groups have to be introduced into ethyl malonate, we first attempted to intro- duce the heavier isopropyl group and then the ethyl group, but after a, long series of preliminary experiments, of which it is not necessary t o give the details, we found that the yield of ethyl ethylisopropyl- malonate so obtained was, relatively speaking, very small ; it could, however, be increased to 75 per cent.of the theoretical by reversing the order of introduction of the alkyl groups, but even then the introduction of the isopropyl group is not an easy matter, the most satisfactory conditions being the following. After treating ethyl ethylmalonate with the calculated quantities of sodium and isopropyl iodide, the portion of the resulting liquid 'boiling below 230' (ethyl ethylisopropylmalonate boils at 230-235') was again treated with sodium and isopropyl iodide (see page go), by which means the yield of pure disubstituted ethyl malonate was increased from 46 to 75 per cent. of the theoretical. The liquid resulting from the hydrolysis of ethyl ethylisopropyl- malonate separates on distillation into two main fractions, one boil- ing at 202-205' (consisting of pure ethylisopropylacetic acid) and the other at about 165-175'.We were at first much puzzled to account for the presence of this liquid of lower boiling point, which had not the characteristic odour of a fatty acid, but smelt more like an ester. On consulting the literature of the subject, we found that Paal and Hoffmann (Ber., 1890, 23, 1497) noticed that when diethyl isoamylmalonate is hydrolysed with alcoholic potash, there is formed, besides the corresponding malonic acid, a considerable quantity of ethyl hydrogen isoamylmalonate, C , H I l * C H < ~ ~ ~ H , which on distillation loses carbon dioxide with production of ethyl isoamylacetate, C,H,1*CH2-C02C,H,. A similar series of reactions appears t o take place in the above instance ; the hydrolysis of diethyl ethylisopropyl- malonate gives rise to ethylisopropylmalonic acid,C,H,* C(C,H7)(C0,H),, and ethyl hydrogen ethylisopropylmalonate.On distillation, both these substances lose carbon dioxide, with the production of ethylisopropylacetic acid and its ethyl ester. The latter constitutes the fraction boiling at 165-175', as was proved both by preparing a specimen of pure ethyl ethylisopropylacetate, which was found t o boil at 164-165', and by hydrolysing the fraction boiling at 165-175', when it yielded pure ethylisopropylacetic acid. We were in all cases obliged to resort to this process of double hydrolysis, for no matter whether we employed 4 or 6 mols. of potass- ium hydroxide, we always obtained considerable quantities of the 2 2 5CONSTITUTION OF FATTY ACIDS.PART XI, 85 fraction boiling at 165--175O, even when the heating was continued for 16 hours. The derivatives of ethylisopropylacetic acid, prepared for the pur- pose of characterisation, are described in detail in the experimental part of this paper. It is interesting to note that the melting point of the amide is as high as 1 3 4 O , for Burrows and Rentley (Trans., 1895, 67, 511) found that the amide OF a similarly constituted and isomeric fatty acid (methylisobutylacetic acid) melted a t 90°, which, as they remark, is a very low meltiug point for an amide of a higher fatty acid. On comparing the physical constants and chemical properties of ethylisopropylacetic and methylisobutylacetic acids, the need of some accurate method for the determination of the constitution of such compounds is well brought out.Methylisobutylace tic acid, CH,. CH( C,H9)*C0,H. Acid ............ B. p. 204-205" Ethyl ester.. .... 17 1 65 -- 1 6 6 Chloride 9 , 152-153 Anilide ......... M.P. 110-111 9 9 90 Amide.. .......... Paratoluidide 1 ) S6 ......... ... Ethylisopropylacetic acid, C,H,*;CH (C, H 7) CO@. B. p. 202-203O 9 , 150-153 M.p. 114-115 ?, 164-165 9, 134-1 34 -5 Y 9 122-123 It will be noticed that the boiling points or melting points of the isomeric derivatives are almost identical, except in the case of the amides and paratoluidides, two derivatives which are not, as a rule, employed for the characterisation of fatty acids, but which, in view of the above, would appear to be worth more general investigation and use.In applying our method to ethylisopropylacetic acid, we first con- verted it into the ethyl ester of the corresponding a-bromo-acid, which was then treated with diethylaniline (see p. 95). From a glance at the formula of ethyl a-bromo-ethylisopropylacetate, it is evident that the elimination of hydrogen bromide may take place in two ways : (CH,),CH* $7Br*CO,Et (CH,),C:y.CO,Et (CH,),CH*fi*CO,Et 7H2 or VH 7% 3 CH3 CH3 Ethyl BB-dimethyl-a- Ethyl B-methyl-a-iso- e thy lacrylate. propylacrylate. and from oxidation experiments we conclude that both reactions occur. It appears, however, that the greater portion of the resulting unsaturated ester is ethyl pp-dimethyl-a-ethylacrylate, that is to say, the hydrogen atom of a CH group is more easily removed, along CH,86 CROSSLEY AND LE SUEUR: DETERMINATION OF THE with the bromine atom, than one of the hydrogen atoms of a CH, group.Diethylaniline therefore seems to exert a certain selective action in such cases, a point on which we hope shortly to furnish more definite information. That the course of the reaction would be twofold was t o be expected from experiments which have been described by W. H, Perkin, jun. (Trans., 1896, 69, 1466, 1490), who has shown that when ethyl a-bromomethylisopropylacetate is treated with quinoline or alcoholic potash a mixture of ethyl trimethylacrylate and ethyl isopropylacryl- ate is obtained. (CHJ,CH*FBr C0,Et (CH,),C:$!*CO,Et - and CH3 CH, Unfortunately, no definite information is given of the ethyl esters produced, but it is shown that ate does not react with the sodium compound (CH,),CH*fl*CO,Et as to the amounts ethyl trimethacryl- of ethyl malonate, CH,.wherea8 ethyl isopropylacrylate does, and calculating from the experi- mental data given, it would appear as if the original mixture of unsaturated ethyl salts consisted of approximately 70 per cent. of the former with 30 per cent. of the latter, thus pointing to the fact that in this case also the hydrogen atom of the CH group is the more t-eadily eliminated. When the mixture of acids resulting from the hydrolysis of the unsaturated ethyl esters is oxidised first with potassium permanganate and then with a mixture of potassium dichromate and dilute sulphuric acid, acetone, acetic acid, propionic acid, and iaobutyric acid are obtained, as was to be expected, P/3-dimethyl-a-ethylacrylic acid giving rise t o acetone and propionic acid, and /3-methyl-a-isopropylacrylic acid to acetic and isobutyric acids by rupture of the double linking. When 25 grams of the acids were oxidised, we obtained, in separate experiments, 1.136, 1.84, and 2.07 grams of acetone.I n the first two instances, the acetone was estimated by the iodoform method, and in the third by precipitation of the p-bromophenylhydrazone. We thought at first that by determining the amount of acetone produced we should get some idea of the proportion of the two unsaturated acids present, but from what follows it will be evident that no such information can be gathered from this experiment. Unfortunately, it is also impossible to accurately estimate the amounts of the various fatty acids produced, but acetic acid is obtained in largest quantity, propionic acid next, and but very little isobutyric acid, Had no side issues to be considered, the amount of propionic acid should be propor- tional t o the amount of acetone, and the amount of acetic acid pro- portional to that of isobutyric acid, but in neither case does this hold good, there being much less acetone than would correspond toCONSTITUTION OF FATTY ACIDS.PART 11. 87 the amount of propionic acid, and much more acetic acid than would correspond to that of isobutyric acid, The explanation of this is not difficult to find, for we have satisfied ourselves that, under the conditions employed, both acetone and isobutyric acid are further oxidised, and thus confirm the statements of Schmidt (Bey., 1874,7, 1363) and Hercz (AnnuZen, 1877, 186,258).Supposing, then, that acetone and isobutyric acid are formed in our experiments as primary oxidation products, they would immediately encounter an excess of oxidising agent, and consequently mould both be largely converted into acetic acid, a fact which would account for the relatively large amount of this acid and for the small amounts of acetone and isobutyric acid which we find. In order to make our experiments more complete and also to supply supplementary evidence, we are a t present investigating more closely the question of the oxidation of the lower fatty acids. Applying the results of our experiments to the determination of the constitution of the acid in question, which for the moment we may presume t o be of unknown structure, the argument would be as follows, Analysis gives the molecular formula C,HI4O2, and as the acid is capable of bromination by Volhard's method, the bromine atom must occupy the a-position.By eliminating this bromine atom together with a neighbouring hydrogen atom, an unsaturated substance is formed, whence it follows that, in the latter, the double bond is between the a- and P-carbon atoms, and that the carbon atom of the 00 or C02H group of any ketone or acid produced from this un- saturated substance by oxidation at the double bond must also have occupied either the a- or P-position in the original acid, I n the case under investigation, we find acetone as one oxidation product, therefore the carbon atom of the ketonic group must have occupied either the a- or P-position in the unsaturated acid, A con- sideration of these alternatives leads to the following results : (1) Occurrence in the p-position.-It follows from what has just been said that the correct grouping of five of the seven carbon atoms is (CH,),C:C*CO,H.Only two carbon atoms are not accounted for, and as there *is but one unsatisfied bond, these must be attached as an ethyl group, so we get as the formulae of the unsaturated and saturated (ethylisopropylacetic) acids. The unsaturated acid, on oxidation, would give acetone and propionic acid, both of which we have been able to identify. ( 2 ) Occurrence in the a-position.-We should then have the following88 CROSSLEY AND LE SUEUR: DETERMINATION OF THE CH grouping, CHS>OCO,H, which, as it necessitates the acceptance of a 3 '* quinquevalent carbon atom, may be a t once dismissed. It might, however, be urged that all the acetone comes from the further oxidation of isobutyric acid.Then, arguing on the same lines as above, we may first place the carbon atom of the UO,H group in isobutyric acid in the P-position, and obtain the following grouping for six out of the seven carbon atoms : (CH,),CH* CH:G*CO,H leading to (CH,),CH* CH:v*CO,H QH3 for the unsaturated acid : an acid which would give acetic and isobutyric acids, together with acetone from the latter on oxidation, but from which it would be impossible to obtain propionic acid. If the carbon atom of the CO,H group is placed in the a-position, we obtain the formula for the unsaturated and the saturated acids.The former would give acetic and isobutyric acids on oxidation, whilst the latter is ethyliso- propylacetic acid, from which acetone and propionic acid can be ob- tained as already shown (p. 8'7). We ccnclude therefore that : (1) With an acid of the type of ethylisopropylacetic acid, our method works just as well as in the cases previously examined (Zoc. cit.). (2) The elimination of hydrogen bromide from the ester of the corresponding bromo-acid takes place in two ways (p. 85). (3) Acetone and propionic acid result from the oxidation of Pp-di- methyl-u-ethylacrylic acid, and acetic and isobutyrio acids from the oxidation of P-methyl-a-isopropylacrylic acid. For the general application of this method, all fatty acids map be divided into four groups : Group I.-Those containing two hydrogen atoms in the a-position, and either one ortwo in the P-position. The theoretical considerations connected with acids of this type have already been given (Crossley and Le Sueur, Trans., 1899, 75, 161), and the process has been carried out with valeric, isovaleric, and isobutylacetic acids.Group 11.-Those containing only one hydrogen atom in the a-position, and either one or two in the P-position. The present communication gives the theoretical considerations and a practical illustration of the method as applied to an acid of this type. Ethylisopropylacetic acid is a particularly good example, be- I n all three cases, the method works well.CONSTlTUTION OF FATTY ACIDS. PART 11.89 Acid. Qroiip I. Group 11. Group 111. A Butyric acids .. ,,. . .. . , . . , . . Valeric acids . . , .. . . . . . . , , . . 1 Hexoic acids . . # ... , . . . . . , . 3 3 1 Heptoic acids ... ... .. . ... .. . 7 6 3 1 2 1 1 cause it contains only one a-hydrogen atom, but two P-carbon atoms, t o one of which there is attached one hydrogen atom, and to the other two hydrogen atoms. Group 111.-Those containing no hydrogen atoms in the a-position. With an acid of the constitution CR,*CO,H, our method cannot be employed, for it is well known that, unless an acid contains an a-hydrogen atom, it cannot be brorninated by Volhard’s method, as tohe molecule breaks up under these conditions (compsre Reformatzky, Be?*., lS90, 23, 1594; Aumers and Bernhardi, Be?*., 1891, 24, 2210).There are, however, so,few acids of this ty1;e, that, given a fatty acid incapable of being brominated by Volhsrd’s method, without decom- position, this in itself would be strong evidence as to its constitution. Group 1V.-Those containing two hydrogen atoms in the a-position and none in the P-position. We cannot ascertain t h a t an acid of this type has been described. It seems probable that such an acid should result from the product of the interaction of ethyl sodiomalonate and dimethylethylcarbinyl bromide, Group IV. A 1 1 E x P E R I M E N T A L. 1, E t IL y li s o p Y o p y l u c e t i c A c i cl. Prepavation of 23th y lisopropy lucetic Acid from Ethyl Eth ylmalonat e. After making a number of preliminary experiments, large quantities of ethyl ethylmalonate were worked up in the following manner.24 -8 grams of sodium (I mol.), dissolved in 300 C.C. absolute alcohol,90 CROSSLEY AND LE SUEUR: DETERMINATION OF THE were mixed with 200 grams of ethyl ethylmalonate (1 mol.), 190 grams of isopropyl iodide (1 mol.) were gradually added, and the whole heated on a water-bath for 15 hours. The greater portion of the alcohol mas then distilled off, and after adding water, the whole was extracted with ether, the ethereal solution dried over calcium chloride, and the ether evaporated. After distilling the residue three times in air, using a fractionating column, the following fractions were collected : Below 210 "... ...... 9 grams 225-230° ......... 28 grams. 210-225 .........66 ,, 230-235 ......... 113 ,, An analysis of the fraction 230-235' gAve the following numbers : C = 62-57 ; H = 9.55. 0.1182 gave 0.2712 CO, and 0.1016 H,O. Ethyl ethyZiso~ro~yZma7onate, C,H5* C( C,H7)(C0,C,H,),, is a clear, colourless, mobile liquid possessing a pungent, rather unpleasant smell, and boiling a t 232-233'. The yield of ester obtained is only 46 per cent. of the theoretical, but this can be materially in- creased by again treating the lower fractions with sodium and isopropyl iodide, in proportions calculated on the supposition that the fraction 225-230' contains 25 per cent. of unchanged ethyl ethylmalonate C,,H,,O, requires C = 62.60 ; H = 9.56 per cent. 210-225 ,, 50 ,, 9 , ?, 9 9 below 210 ,, 100 ,, >, 9 , ,? I n this way, 70 grams of liquid boiling between 230-235' were obtained, thus bringing the total yield of ethyl ethylisopropylmalonate up t o 75 per cent.of that theoretically obtainable from the ethyl ethylmalonnte employed. EthyZisoprop~ZmccZonic m i d , C2H5*C(C3H7)(C02H)2, was obtained by hydrolysing the ester with alcoholic potash, and after recrystallisation from benzene was analysed. 0.1670 gave 0.3370 CO, arid 0.1194 H,O. This acid is insoluble in cold light petroleum (b. p. SO-loo'), readily soluble in acetone, alcohol, or water, and crystallises from benzene in beautiful, glistening needles melting at 131-131*5'. At a higher temperature, it evolves carbon dioxide, giving rise to the corresponding fatty acid. The silver salt, prepared in the ordinary manner, is a white, curdy precipitate.0,2032 gave on ignition 0.1134 Ag. C= 55.04 ; H=7*94. C8H,,0, requires C = 55-17 ; H = 8.05 per cent, Ag=56°80. C,€l,,O;,Ag, requires Ag = 55.67 per cent.CONSTITUTION OF FATTY ACIDS. PART 11. 91 EthyZisopropyZcccetic acid, C,H,*CH(C,H7)*C02H.-422 grams of ethyl ethylisopropylmalonate were heated for 10 hours on a water-bath in quantities of 100 grams a t a time with 150 grams (6 mols.) of potass- ium hydroxide dissolved in alcohol. Water was then added, the alcohol evaporated, and after acidification with sulphuric acid the whole was extracted with ether, the ethereal solution carefully dried over calcium chloride, and the solvent evaporated. The residue, after heating to eliminate carbon dioxide, was repeatedly distilled, using a fractionating column, when the following fractions were collected : Below 190 O.........69.5 grams. 196-200' ...... 12.0 grams, On further distillation of the portion boiling between 200-205°, pure ethylisopropylacotic acid boiling constantly at 202-203' was obtained. It is a clear colourless, oily liquid, with a disagreeable and penetrating odour, similar to that of other acids of the fatty series. It is readily attacked by potassium permanganate in alkaline solution. 190-196 ......... 18.0 I , 200-205 ...... 128.0 9 , 0.1466 gave 0.3476 CO, and 0.1412 H,O. C7HI4O2 requires C = 64.61 ; H = 10.77 per cent. The siZvei* salt, prepared in the usual manner, is a white caseous 0,1988 gave on ignition 0,0902 Ag. C7H,,0,Ag requires Ag = 45.57 per cent. We were for some time unable to account for the large fraction boiling below 190°, of which the major portion passes over between 165' and 170'; fhrther experiments showed, however, that the latter temperature is about the boiling point of ethyl ethylisopropylacetate (164-165'), and the course which the reaction is supposed to follow has already been explained in the introduction (p.84). The whole of the liquid boiling below 200' was therefore again hydrolysed with alcoholic potash, when a further 60 grams of pure ethylisopropyl- acetic acid were obtained, thus increasing the yield to 80 per cent. of that theoretically obtainable from the corresponding disubstituted malonic ester. C=64*66 ; H=10-71. precipitate. Ag= 45.39. Preparation of EthyZisopropyZacetic Acid from Ethyl a-Cyanoacetate.Ethyl a-cyanoacetate was first converted into ethyl a-cyanobutyrate, C2H5* CH(CN)*CO,C,H, (b. p, 208--209O), by heating with sodium and ethyl iodide in alcoholic solution. Three soda-water bottles, each containing 6 grams of sodium dis- solved in 60 c . ~ , absolute alcohol, 31 grams of ethyl a-cyanobutyrate,92 CROSSLEY AND LE SUEUR: DETERMTNAT'ION OF THE and 40 grams of isopropyl iodide, were securely corked, and heated in a water-bath for 20 hours, Water was then added to the contents of the bottles, and the whole extracted with ether, &c. ; the resulting liquid was then fractionated, using a column, with the following results : Below 205' ......... 11.5 grams. 230-225' ......... 35-5 grams. 205-215 ......... 3.5 ,, 225-230 ......... 23.0 ,, 215-220 .........10.5 ,, A nitrogen determination in the Fraction 225-23OOgave the follow- 0.1416 gave 10 C.C. moist nitrogen at 23' and 766 mm. Ethyl a-cy(moet?$isopropyZacetate, C,H,* C( C,H,)( CN) C02C2H5, is a clear, colourless liquid having a faint odour of peppermint, and boils a t 226-227' under 756 mm. pressure. The yield is poor (20 per cent. OF the theoretical), but may be increased to 50 per cent. of the amount theoretically obtainable from the ethyl cyanobutyrate used, by again treating the lower fractions with sodium and isopropyl iodide, on the same principle as described in the preparation of ethyl ethylisopropyl- malonate (p. 90). Dilute sulphuric acid seems to be the best agent for hydrolysing this ester, but the results are not very satisfactory, and the yield of fatty acid is small. The ester was boiled for 30 hours with four times its weight of 55 per cent. sulphuric acid, and after dilutiug with water the whole was extracted with ether, the ethereal solution dried over calcium chloride, and the ether evaporated. On fractionating the resulting liquid, the major portion distilled between 200' and 205", and by repeating the process an acid liquid was obtained boiling at 202-203' and having all the properties of ethylisopropylacetic acid.It gave a white, insoluble silver salt, which was analysed : ing numbers : N = 8.02. C1,H1702N requires N = 7.65 per cent, 0.1532 gave on ignition 0.0702 Ag. Ag = 45.82. C7H,,02Ag requires Ag = 45-57 per cent. The p-toluidide crystallised from light petroleum (b. p. 60-SOo) in slender, glistening, silky needles melting a t 121-122' (compare I f ethyl cyanoethylisopropylacetate is heated with dilute sulphuric acid only for 15 hours, the greater part of the resulting liquid was found to boil between 160-170°, a small amount passing over between 230' and 240°, which solidified on cooling.The fraction 160-170" consisted probably of the nitrile of ethylisopropylacetic p. 94).CONSTITUTION OF FATTY ACIDS. PART IT. 03 acid, which, from analogy, would be expected to boil a t about this temperature ; moreover, when heated with dilute sulphuric acid, this fraction is converted into ethylisopropylacetic acid. The solid fraction (b. p. 230-240") crystallised from light petroleum in white, silky needles melting a t 133*5-134" (see p. 94) and consisted of ethyliso- propylacetamide.0,1338 gave 12.8 C.C. moist nitrogen a t 17" and 752 mm. N = 10.98. C,H,,ON requires N = 10.85 per cent. I n one of the first experiments me made on the hydrolysis of the above ester, a portion was heated for 12 hours with 5 times its volume of concentrated hydrochloric acid, but, as on extraction with ether, &c., the boiling point of the resulting liquid mas found to be that of the original -ester, the whole was heated with concentrated aqueous potassium hydroxide for 15 hours, during which process considerable quantities of ammonia were evolved. The residue extracted from the acidified liquid was found to boil for the most part below 200°, and n small portion boiling between 230' and 240' solidified on cooling. This substance crystallises from water, or, better, from light petroleum (b.p .80-100°) in beautiful, silky needles melting a t 122--122*5O, and does not sublime when heated in a dry test-tube. 0.1416 gave 13.8 C.C. moist nitrogen a t 23.5' and 760 mm. N = 10.95. C,H,,ON requires N = 10.85 per cent. Although resembling ethylisopropjlacetamide, it melts at a tempera- ture 13 degrees lower, and we have, so far, been unable to satisfactorily prove its exact nature, the amount obtained being very small, Derivatives of Ethglisopopylacetic Acid. Ethyl ethylisopropylncetute, C2H,* CII( C,H,) * CO,C,H,.-Pure ethyl- isopropylacetic acid was dissolved in absolute alcohol, dry hydrogen chloride passed in to saturation, and the whole left for 24 hours. After pouring into water and extracting with ether, &c., it, was found that very little of the ethyl salt had been formed, as nearly the whole of the residue boiled between 200' and 2 0 5 O , and consisted therefore of un- changed acid. This observation appears t o be in accord with those of Menschutkin and others, who have shown that acids of this type are not readily esterified in this manner.After several further fruitless experiments, the following method was adopted. 10 grams of the pure acid were dissolved in 25 C.C. of absolute alcohol, and after adding 10 C.C. of concentrated sulphuric acid, the vhole was heated on a water-bath for 8 hours; water was then added, and the oil which separated was extracted with ether. The ethereal94 CROSSLEY AND LE SUEUR: DETERMINATION OF THE solution was washed with dilute sodium carbonate, then with water, carefully dried over calcium chloride, and the ether evaporated, On fractionating the residue, 11 grams (91 per cent.) of a liquid boiling constantly a t 164-165" under 765 mm.pressure were obtained, 0.1486 gave 0.3708 CO, and 0.1510, H,O. The ester is a clear, colourless, mobile liquid with a characteristio, penetrating smell. EthyZisopropp?acetumide, C,H,* CH(C3H7) COwNH2.-The ester was heated in a sealed tube with concentrated aqueous ammonia for 12 hours at 180°, but was recovered unchanged. The same result was obtained when alcoholic ammonia was employed, Some of the pure acid was then heated for 10 minutes in a reflux apparatus with the calculated quantity of phosphorus pentaohloride. After distillation, the crude chloride boiling between 150° and 153O was slowly poured into concentrated aqueous ammonia, when a white solid separated, which was collected, spread on a porous plate, crystal- lised from light petroleum, and analysed, 0.1166 gave 11.0 C.C.moist nitrogen at 21Oand 764 mm. N = 10.80. C,HI,ON requires N = 10.85 per cent. The amide is but slightly soluble in chloroform, benzene, or acetone, but readily in alcohol or water, and crystallises well from either light petroleum or water in long, white, silky needles melting at 134-134.5O. When heated in a test tube, it sublimes in needle-shaped crystals. EthyZisopropykccetarLilide, C,H,* CH(C,H,) *CO*NH* C,H,, prepared by heating the pure acid with twice its weight of pure aniline for 24 hours, was purified in the usual manner, and finally by recrystal- lisation from light petroleum (b.p. 100-120°), from which it separated in clusters of small, glistening needles melting a t 114-1 15O. It is insoluble in water, but readily soluble in alcohol, chloroform, acetone, or ether. C = 68.06 ; a= 11.33. C,H,,O, requires C = 68.35 ; H = 11 -39 per cent, 0.1580 gave 9.6 C.C. moist nitrogen at 20' and 762 mm. C,,H,,ON requires N = 6.83 per cent. EthyZiso~opyktcetpara~oZ~~~~de, C2H5* CH(C,H7)* CO*NH* C,H7, pre- pared and purified in a similar way to the anilide, crystallises from light petroleum (b. p. 60--80°) in glistening, feathery needles melting at 122.5-123O. It is insoluble in water, but readily soluble in the ordinary organic solvents, even in the cold. N=6*36, N = 6-96.0.1994 gave 11.0 C.C. moist nitrogen at 19' and 762 mm. C,,H,ION requires N = 6.39 per cent.CONSTlTUTION OF FATTY ACIDS, PART 11, 95 11. E t h y I a- B r o m o e t h y I i s op r op y l a c e t a t 8. Ethyt a-bromoethylisopropyhcetate, C,H,* CBr(C,H,) * CO,C,H,.- Ethylisopropylacetic acid was treated in quantities of 50 grams at a time with 4 grams of amorphous phosphorus and 120 grams of dry bromine (Volhard, dnnalen, 1887, 242,61). On pouring the resulting bromide into alcohol, very little heat is developed at first, but on standing the temperature gradually rises, and eventually it is necessary to moderate the reaction. The resulting ester of the bromo-acid is a colourless, mobile liquid, possessing a pungent, characteristic smell somewhat resembling that of peppermint.It boils constantly a t 135-136' under 59 mm. pressure, and is obtained in almost theoretical amount (92-93 per cent.). 0.2440 gave 0.1950 AgBr. Br = 33.97. C,HI7O,Br requires Br = 33.76 per cent, Treatment of Ethyl a-Bromethyli~opi~opyZ~1cetats with BietJhylaniline, 356 grams of the ester were treated in portions of 50 grams (1 mol.) a t a time with 63 grams (2 mols.) of freshly distilled diethyl- aniline, and worked up in the manner already described (Trans., 1899, 76, 166). As the residual liquid was found to contain traces of bromine, it was again heated with 1 mol. of diethylaniline for 8 hours, and then distilled in air. After five distillations, the follow- ing fractions were collected under 748 mm. pressure : 170-175' ......2 grams. 185--200' ...... 5 grams, 175--180 ...... 170 ,, Above 200 ...... 28 ,, 180-185 ...... 5 ,, The frccction boiling at 175-1SO'was found to be entirely free from 0.1094 gave 0.2774 CO, and Oa1008 H,O. C,H1,O, requires C = 69.23 ; H = 10.25 per cent. So far this is the only instance in which we have found it possible to entirely eliminate bromine by using diethylaniline ; as a rule, the analyses of such unsaturated esters do not lead to satisfactory results, owing t o the presence of small amounts of halogen. This fraction, amounting t o '73 per cent. of the product, is a clear, colourless, mobile liquid possessing a very pungent odour of peppermint ; although of fairly constant boiling point, it is not a simple substance, but as the oxidation experiments show, consists of a mixture of ethyl P/3-dimethyl-a-ethylacrylate and ethyl p-methyl-a-isopropylacrylate. bromine, and gave the following numbers on analysis : C = 69-15 ; H = 10.24.96 CROSSLEY AND LE SUEUR: DETE€iMINATION OF THE Hydrolpis of the Mixed Esters.170 grams of the mixed esters were hydrolysed in two portions with 120 grams of caustic potash dissolved in alcohol. The mixture of acids obtained from the product had the remarkable property of boiling quite constantly at 136O under 55 mm. or at 203-204' under 760 mm. pressure. It is a clear, colourless liquid, with a faint but sharp odour ; i t rapidly decolorises a chloroform solution of bromine, and also an alkaline solution of potassium permanganate. Oxidation of the mixed Unsaturated Acids. The mixed acids were oxidised (cornpare Trans., 1899, 75, 165) in quantities of 25 grams, first, with 23 grams of potassium permanganate and then with 60 grams of potassium dichromate dissolved in dilute sulphuric acid.During the second operation, an absorption apparatus was connected with the end of the condenser, in order to avoid loss of acetone. The oxidation took place very readily, in spite of the fact that the acids are insoluble in water, and was complete i n from 3-4 hours. The product wa8 distilled with steam until no more acid passed over, the distillate carefully neutralised with potassium hydroxide, again distilled with steam, and the second distillate treated with a n alcoholic solution of p-bromophenylhydrazine, when a copious precipitate separated.This was collected and recrystallised from light petroleum, when small, glistening leaflets of the p-bromophenyl- hydrazone derivative of acetone, (CH,),C:N*NH*C,H,Br, were ob- tained melting at 94-95" (compare Neufeld, A?znat!en, 15135,248, 96). C9HllX2Br requires Br = 35.24 per cent. The contents of the distillation flask were evaporated to dryness, and the potassium salts, rendered anhydrous by heating at 100" i n a n air oven, were distilled with concentrated sulphuric acid, when a good deal of charring occurred. The liberated fatty acids (13-14 grams from 25 grams of the unsaturated acids) were dried by standing over concentrated sulphuric acid and then distilled fractionally, when no substance of higher boiling point than 160" was obtained. I n subsequent experiments, the process was somewhat modified, inasmuch as the potassium salts were dissolved in dilute sulphuric acid, and the whole extracted 10 times with pure ether.The ethereal solution was dried over calcium chloride, the ether removed by evapora- tion, and the residual fatty acids distilled, the following fractions being collected : 0.1212 gave 0.0994 AgBr. Br = 34-90, 100-1 1 0" 125-1 35" 145-150" 110-1 25 135-145 150-160CONSTITUTION OF FATTY ACIDS. PART 11. 97 The thermometer rises very rapidly from 160' t o 200°, at about which temperature the residue passes over, and consists presumably of incompletely oxidised acids, The various fractions were further purified by drying over anhydrous sodium sulphate and repeated distillation. Fraction boiling at 100-1 25".-This contains aeetic acid, CH,*CO,H.A portion of this fraction boiling at 118' was converted into the silver salt, which after recrystallisation from water was analysed. 0.1288 gave on ignition 0.0834 Ag. C,H,O,Ag requires Ag = 64.67 per cent. A further quantity of the acid boiling between 117-119' was con- verted into the anilide, which crystallised from water in pearly scales melting at 112-112.5". 0.1024 gave 9.2 C.C. moist nitrogen at 20' and 764 mm. N= 10.33. Fraction boiling at 135-1 45".-This contains propionic acid, The silver salt, prepared from a portion of the acid Ag = 64.74. CH,*CO*NH*C,H, requires N = 10.37 per cent. CH,*CH,*CO,H. boiling at 140°, gave the following numbers on analysis : 0.1520 gave on ignition 0*0908 Ag. C,H50,Ag requires Ag = 59.66 per cent.The anilide prepared from the acid boiling between 139-141' crystallised from light petroleum in glistening leaflets melting at 103-104' (compare Trans., 1898, 73, 34). Ag = 59.73. 0.1429 gave 12 C.C. moist nitrogen at 20" and 753 mm. C,H,*CO*NH*C,H, requires N = 9.39 per cent. Fraction boiling at 150-1 60°.-This contains isobutyric acid (CH,),CH*CO,H. The portion of this small fraction boiling between 153" and 157" was converted into the calcium salt by heating the acid dissolved in water with pure calcium carbonate, filtering, and evaporating the filtrate in a vacuum, when radiating clusters of silky needles were obtained, in which, after drying in air, the water of crystallisation was determined. N=9.51. 0.3536 lost 0.0702 at 155".0.2368 gave 0.1536 CaSO,. (C,H,O,),Ca requires Ca = 18-69 per cent. According to Chancel and Parmentier (Compt. red., 1887,104,477), calcium isobutyrate should contain 5H,O, requiring 29.6 per cent. H,O, but, as has repeatedly been shown (Trans., 1898, 73, 15, 35 ; also 1899,75, 185), the salt prepared i n the above manner contains H,O= 19.85. Ca = 19-07. VOL. LXXVII. H98 DETERMINATION OF THE CONSTITUTION OF FATTY ACIDS. water corresponding more nearly with 4H,O (25.17 per cent.), the amount depending to a large extent on the length of time during which the salt has been exposed to air (Trans., 1898, 73, 15). The unusually small proportion of water found above appears to be due to the facts that, first, as the calcium analysis shows, the salt was not quite pure, and, secondly, when the solution of the salt was evaporated sufficiently for it to crystallise, the surface became coated with a crust, from which, on account of the small amount of material, it was very difficult to completely detach the crystals.As mentioned on p. 95, when ethyl a-bromoethylisopropylacetate is treated with diethylaniline, 28 grams of a substance boiling above 200' were obtained, besides the unsaturated esters, On distilling this under 65 mm. pressure, 8 grams were found to boil below 200°, and 14 grams between 205-2109 As both fractions contained nitrogen, it was thought that an ethyl ester of an anilino-acid might have been produced, for, as Bischoff (Bey., 1898, 31, 3015) has shown, these substances are formed by the action of dimethylaniline on the ethyl esters of a-bromo-acids of the fatty series, but it appears not to be so in this case, The fraction boiling below 200' was treated with ;alcoholic potash, the alcohol evaporated, and a small amount of an insoluble nitrogen- ous substance removed by ether.On acidifying and extracting with ether, 7 grams of a liquid boiling between 207-209' were obtained, which exhibited all the properties of the mixture of unsaturated acids described on p. 96. A portion was converted into the silver salt and analysed. 0.1708 gave, on ignition, 0.0788 Ag. The fraction boiling at 205--210' was again distilled, and a portion 0.1558 gave 0,4264 CO, and 0.1288 H,O. 0.2261 N = 7.06. 0.2090 ,, 11.9 C.C. ,, > ? ,, 15' ,, 770 mm. N=6.76. C,,H,,O,N requires C = 73.64 ; H = 9.71 ; N = 5.05 per cent. These numbers do not agree with those required for the ethyl ester of the corresponding anilino-acid. Some of the liquid was then heated with excess of alcoholic potash for 7 hours, Water was added and the alcohol evaporated, when on extracting the alkaline liquid with ether, nearly the total weight of liquid originally taken was obtained. It boils constantly at 290-295O under 750 mm. pressure, is a thick, pale yellow liquid with a marked blue fluorescence, and gave C = '76.52, Ag=46.13. C7Hl10,Ag requires Ag = 45.96 per cent. boiling at 207-208° under 60 mm. pressure was analysed : C: = 74.64 ; H = 9.18. ,, 13.6 C.C. moist nitrogen at 16' and 766 mm.HEWITT : PREPARATION OF BENZENEAZO-0-NITROPHENOL. 99 H=8*99, N=7*31 per cent. as the mean of three closely agreeing analyses. It dissolves in concentrated sulphuric or hydrochloric acids, but is thrown out of solution on adding water. With concentrated sul- phuric acid and a crystal of potassium dichromate, it gives a rose-pink colour turning to greenish-brown. Concentrated nitric acid dissolves it, and on evaporation a rose-pink colour is developed. Potassium permanganate is readily decolorised by it, but no definite oxidation product could be isolated, and we have so far been unable to decide the nature of this substance. Our thanks are due to the Research Fund Committee of the Chemical Society for a grant defraying in part the cost of the materials used in this investigation. CHEMICAL LABORATORY, ST. THOMAS’S HOSPITAL.

ISSN:0368-1645    

DOI:10.1039/CT9007700083

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

HEWITT : PREPARATION OF BENZENEAZO-O-NITROPHENOL. 99 X. -Preparation of Benxeneazo-o-nitrophenol. By J. T. HEWITT. BENZENEAZO-O-NITROPHENOL being required for some work on which the author of the present communication is engaged, an attempt was made to prepare it in a more satisfactory manner than according to Noelting’s process, which consists in adding a solution of a phenyl- diazonium salt to an alkaline solution of o-nitrophenol (Bey., 1887, 20, 2997). Diazotisecl amines combine but slowly with o-nitro- phenol, and during the process considerable decomposition sets in, the yield being small. Direct nitration of benzeneazophenol gave p-nitro- benzeneazophenol (Noelting, Zoc. cit.), the method consisting in carrying out the nitration in a strong sulphuric acid solution. It seemed possible, however, by altering the conditions of the experiment, that substitution might take place in the phenol nucleus, and that if so, the desired o-nitro-compound would be obtained, as it was very improbable that the nitro-group should enter in the meta- position, whilst the para-position is already occupied by the azo-group, The desired result mas obtained, the necessary conditions being that the nitric acid is sufficiently dilute and the temperature carefully regulated.* * E. Tauber (Ber., 1893, 26, 1872) has described the nitration of phenolazo. benzenesulphonic acid in strong sulphuric acid, and obtained a nitro-derivative100 HEWlT'r : PREPARATION OF BENZENEAZO-0-NITROPHENOL. 10 grams of benzeneazophenol (powdered) are stirred up and thoroughly moistened with a cold mixture of 20 C.C.nitric acid of sp. gr. 1.36 and 60 C.C. mrtter. The mixture is then carefully warmed on the water-bath, the temperature being gradually raised t o about 40° (the temperature of the water-bath should not be above 45'). After about 20 minutes, a smell resembling that of o-nitrophenol is noticeable, the mass becomes thicker, and eventuiillg bubbles of gas make their appearance. At this stage, when the contents of the beaker have become a stiff paste, in which the thermometer will stand upright, they are added to an excess OC cold water, and the insoluble part collected rapidly with the aid of .a pump and well washed. After drying at looo, the weight of yellow precipitate is generally 74 grams, and the melting point about 122' (not quite sharp).Noelting gives 126' as the melting point of benzeneazo-o-nitrophenol ; after three recrystsllisations from benzene, the melting point of the above product was found to be constant at 126.5' (128.5' corrected ; the remaining melting points in this paper are all corrected for the apparent expansion of the mercury of the thermometer). The com- position of the substance was controlled by an analysis. 0.1200 gave 0.2572 GO, and 0.0390 H,O. 0*1377 ,, 21.0 C.C. moist nitrogen at 16'and 762 mm. N= 17.76. C,,H90,N, requires C = 59.21 ; H = 3.73 ; N = 17.32 per cent. If considerable quantities are desired, benzeneazophenol may be nitrated in much greater amount than 10 grams at a time, and after checking its melting point, the product can be used for most purposes without recrystallisation.As benzeneazo-o-nitrophenol could be obtained in considerable quantities, it was considered desirable t o characterise the compound more closely than had hitherto been done. The substance crystallises in small light yellow needles, gives a pale yellow powder, and forms yellow solutions in organic solvents. In strong sulphuric acid, it dissolves with a red colour, and the careful addition of water to the solution at first precipitates a red sulphate which, however, very readily gives the yellow nitrophenol on further addition of water. Whether the precipitate so obtained is a hydrate or the free azophenol, has not so far been determined. Farmer and Hantzsch state in a recent paper (Ber., 1899,32, 3098) t h a t this azophenol (or, U=58*46 ; H=3*61. with the nitro-group in the ortho-position relatively to the hydroxyl. He expressly mentions in his paper that he has chosen such a sulphonio acid derivative as otherwise the nitro-group would enter the benzene, and not the phenol, nucleus.The course of the substitution really depends on whether an azophenol reacts as such, or as a salt of a mineral acid.in their nomenclature, Nitrochinoln-PhenyZhydl.azofi) gives neither hydrate nor hydrochloride. The existence of the sulphate shows, however, that the azophenol is capable of forming salts with strong acids. Solutions of the azophenol in fixed alkalis and ammonia are of a distinct red shade, in fact, the difference of colour between the free phenol and its alkaline salts strongly recalls the relationship in colour between o-nitrophenol and its alkali salts.The sodium salt separates in red needles on concentration, and in neutral solution gives, with solutions of metallic salts, the following precipitates. Silver Nitl.de.-Light orange precipitate, practically insoluble, even in boiling water. Nagnesium Chloride. -Orange precipitate, dissolves somewhat in boiling water, and separates in groups of small needles on cooling. Zinc #ulphata.-Bright yellow precipitate, becoming crystalline on warming, slightly soluble in boiling water. Cadmium SuZ'hute.-Orange precipitate, very slightly soluble. Mercuric ChZo&de.-Yellow precipitate, appreciably soluble in boil- Calcium CIJoride.-Orange red precipitate, very slightly soluble in Strontium Chloride.-Similar precipitate to that with calcium Buvium Chloride.-Scarlet precipitate, very sparingly soluble in Lead A cetate.-Orange precipitate, insoluble.Copper 8uZphute.-Dirty orange precipitate, insoluble. Cobalt Nitrate or Nickd Chloride.-Reddish-brown precipitate. Manganese SuZphate.-Orange precipitate, somewhat soluble in Stunnous ChZovide.-Bright sulphur-yellow precipitate. I l ' e . n . 0 ~ ~ SuZphate.-Dark brown precipitate, soon turning green. Ferric ChZoride.-Bright sulphur-yellow precipitate. Aluminium SuZphute.-Bright yellow precipitate. Chrome AZum.-Yellow precipitate, not quite so clear in shade as that with aluminium. It is somewhat striking that the colours of the precipitates should vary so much. The very slight solubility of the barium salt contrasts strongly with that of the barium salts of benzeneazophenols containing the substituents in the benzene nucleus, which may be recrystallised easily from boiling water and are obtained as orange needles contain- ing 4H,O.The acetyl derivative, C,H,*N :N*C6H,(N0,)*O*CO*CH,, is easily VOL. LXXVII. I ing water. boiling water, chloride, but somewhat redder in shade. boiling water, from which it separates in very slender, long needles. boiling water.102 HEWITT : PREPARATION OF BENZ ENEAZO-0-NITROPHENOL, obtained by warming 2 parts of the azophenol, 2 parts of fused powdered sodium acetate, and 5 parts of acetic anhydride for 1 hour on the water-bath. It separates in a Bocculent state on pouring into water, and may be obtained as yellowish-brown prisms by recrystal- lisation from glacial acetic acid or benzene.It melts at 120.5O. 0.1237 gave 0-2644 CO, and 0.0428 H,O. C = 58-29 ; H = 3.85. 0.1103 ,, 14.5 C.C. moist nitrogen at 21" and 756 mm. N = 14.89. C1,HllO,N, requires C = 58-90 ; H = 3.89 ; N = 14.77 per cent. The acetyl derivative is easily soluble in acetone, ethyl acetate, or pyridine, less so in chloroform or benzene ; methylated spirit dissolves it sparingly in the cold, but fairly readily on warming, as does amyl alcohol. It is sparingly soluble in ether and insoluble in light petroleum. The benzoyl derivative,C,H,*N:N*C,H,(NO,)*O* CO* C,H,, is obtained when equal weights of the azophenol and benzoyl chloride are boiled gently for 1 hour. After pouring the product into water and leaving it until it has solidified, it is powdered, warmed with a little alcohol, and washed with repeated small quantities of cold alcohol on the pump.It separates from benzene in small, yellow crystals, melts a t 132O, is easily soluble in hot benzene, acetone, or chloroform, sparingly so i n alcohol or light petroleum, and is only dissolved in very small quantities by ether. N = 13.07. 0,1127 gave 12.4 C.C. moist nitrogen a t 13" and 764 mm. C19H,,04N, requires N = 12-72 per cent. The difference in the behaviour of benzeneazophenol on nitration, when the operation is effected with dilute acid or in concentrated sulphuric acid solution, might be explained if benzeneazophenol had the constitution, C,-H,*N:N* C,H,*OH, usually assigned to it. Phenofs undergo substitution much more readily than benzene derivatives, in which no hydroxyl or amino-groups are present, and hence nitration might be expected t o occur in the phenol nucleus.On the other hand, when nitration takes place in a sulphonic acid solution, a salt of the azophenol with a mineral acid is being nitrated, and if to these salts a formula is assigned, such as that which Hantzsch (Ber., 1899, 32, 3091) gives to the hydrochloride, the result is also easily explicable. Quinones are substituted with comparative difficulty, amines, on the contrary, with ease, an ortho- or a pars-deriva tive being produced. Hantzsch, however, assigns a similarLEAN : TETRAHYDROFURFURAN-2 : 5-DICARBOXYLIC ACID. 103 quinonoid structure to the free azophenols, and this seems to be hardly reconcilable with the experiments just described. It may be pointed out that the colour of the free azophenols much more closely corre- sponds to that of their ethers and esters, which undoubtedly possess the azo-structure, than to that of their salts with mineral acids for which the structure of quinone-hydrazone derivatives is probable, The author desires to thank Messrs. Clncher and Likiernik for help afforded in this work. EAKr LONDON TECHNICAL COLLEGE,

ISSN:0368-1645    

DOI:10.1039/CT9007700099

出版商:RSC    

年代:1900

数据来源: RSC