摘要:

1376 MORGAN: INFLUENCE OF SUBSTITUTION ON THE CXXXVIII.-Injuence ofXubstitution on the Formation of Diuxoamines und A minoaxo-compounds. By GILBERT THOMAS MORGAN, D.Sc. THE results recorded in a former communication (this vol., 91) showed that 1 -chloro-j3-naphthylamine, unlike the parent base, P-naphthyl- amine, gives rise to diazoamines when treated with diazonium salts. P-Naphthylamine-8-sulphonic acid behaves similarly (Witt, Ber., 1888, 21, 3483), and it may therefore be generally supposed that the presence of a substituent radicle in either of the positions 1 and 8 of the naphthalene nucleus causes the diazo-complex to remain attached to the aminic nitrogen atom situated in position 2. It has been shown more recently by C. Smith (this vol., 901) that a similar effect is produced by hydrogenising the unsubstituted naphtha- lene nucleus, this investigator having demonstrated that ar-tetrahydro- P-naphthylamine does not, as' was formerly supposed, condense with diazonium salts to form aminoazo-compounds, but under these con- ditions furnishes diazoamines.The products of the action of diazotised m-nitroaniline and m-chloro- aniline on the tetrahydro-base could not, however, be isolated, as they are unstable a t the ordinary temperature and rapidly change into resinous subs tames. m-Nitrobenxene-2-diaxoumino-1-chZoronu~?~t?~aZene, obtained by the action of m-nitrobenzenediazonium chloride on I-chloro-P-naphthyl- amine is, on the contrary, quite stable at the ordinary femperature, Part 11-FORMATION OF DIAZOAMINES AND AMINOAZO-COMPOUNDS. 1377 and is readily obtained in a crystalline form.Nevertheless, it shows itself to be less stable than its 0- and pisomerides by decomposing at a temperature nearly 70° lower than the decomposition point of these substances. o~Niti~obenxene-2-dia~~c~~~no-l-chlo~~onaph~haZene closely resembles the p-isomeride already described (this vol., '99), and is prepared in a similar manner. An attempt made to prepare a similarly constituted mixed diazo- amine from diazotised I-nitro-P-naphthylamine led t o a curious and unexpected result. The solution obtained by treating 1 -nitro-P-naphthylamine suspended in hydrochloric acid with sodium nitrite, when mixed with a glacial acetic acid solution of 1-chloro-P-naphthylamine, gave rise t o a diazo- amine which proved to be 2-diazoamino-l-chloronaphthalene, C1,H6C1*N,*NH*C,,H,C1, the yield of this product being such that it could not possibly be derived entirely from the chloro-base actually intro- duced.All the mother liquors obtained in the experiment were examined, but no trace of the nitro-base or its diazonium salt could be found. The aqueous filtrate from the diazoamine still contained a diazonium salt, and was accordingly added t o an alkaline solution of P-naphthol ; the azo-compound thus produced consisted entirely of 1 -chloronaph thalene-2-axo-P-naphthol. The alcoholic washings from the crude diazoamine were evaporated and the oily residue acetylated, the product being identified as l-chloro- aceto-P-naphthalide, . As a result of this examination, it was found that, although the total yield OF the products accounts for the united weights of the two bases employed, yet the substances formed during the reaction are wholly derived from 1-chloro-P-naphthylamine.This result admits of only one interpretation, namely, that under the above conditions the diazonium salt of the nitro-base becomes transformed into the corresponding derivative of the chloro-base, NO,* Cl,H,*N,Cl -+ C,,H6C1*N,~N0,. This rearrangement corresponds with the observations of Meldola and Eyre (Trans., 1901, 80, 1077, and this vol., 988) as to the behaviour of the diazotised dinitroanisidines ; these substances lose nitro-groups occupying the ortho- or para-position with respect to the diazonium radicle in exchange for hydroxyl or chlorine. Moreover, the replace- ment of substituent radicles by hydroxyl has already been observed in diazo-derivatives of the naphthalene series (Gaess and Ammelburg, Bey., 1894, 2'7, 2211 ; Meldola and Streatfeild, Trans., 1895,67, 909).When the diazo-solution, obtained by adding sodium nitrite to 1-nitro-P-naphthylamine suspended in alcoholic hydrochloric acid, is a t once added to an alkaline solution of @-naphthol, the precipitate pro- duced consist,s of a mixture of l-chloronaphthalene-2-azo-~-naphthol1378 MORGAN: INFLUENCE OF SUBSTITUTION ON THE with the corresponding nitroazo-compound. This result indicates that the transformation requires an appreciable interval of time for its completion, This reaction will be made a subject for further research. Concurrently with the above investigation, the study of the action of diazonium salts on the disubstituted m-diamines has been carried on in conjunction with Mr.G. M, Norman. The action of diazonium salts on diamines of the types I, II, and IV, Y X Y has already been investigated, the results indicating that the bases of the series I and I1 form axo-derivatives in practically theoretical amounts, whereas the symmetrically constituted diamines, IV, give rise t o azo-compounds far less readily, the yields being comparatively small. This difference is attributable to the fact that, in the first two series, the diazo-complex can enter a para-position with respect t o amidogen, whereas in series IV only an ortho-position is available. The diamines corresponding with formula I11 actually contain two reactive para-positions, and i t might be supposed that these bases would yield azo-derivatives with great facility.Experiments were ac- cordingly instituted with the view of placing on record the production of azo-compounds from 2 : 6-diamino-p-xylene and 2 : 5-dichloro-m-phenyl- enediamine. In the case of the former base, our investigations were anticipated by Noelting and Thesmar ( B e y , 1002, 35, 628), who described the azo- compound, benzene-3-azo-2 : 6-diamino-p-xylene, obtained from this di- amine by the action of benzenediazonium chloride. 2 : 5-Dichloro-m-p~enylenediccmine is obtained by the reduction of the corresponding dinitro-p-dichlorobenzene, a substance produced by the direct nitration of p-dichloro ben zene. The nitration product consists chiefly, however, of the isomeric 2 : 5-dinitro-1 : 4-dichlorobenzene, the required 2 : 6-dinitro-1 : 4-dichloro- benzene being only a bye-product.This result is of interest, because it affords another illustration of the fact that as substitution progresses the rules governing the orient- ation of the entrant radicles become considerably modified. ForFORMATION OF DIAZOAMINES AND AMINOAZO-COMPOUNDS. 1379 example, the nitration of nitrobenzene or any benzenoid mononitro- compound containing only one other substituent leads to the formation of a metadinitro-compound as the chief product, this result being in accordance with the ‘( meta ” law of substitution. When, however, the molecule already contains two other substituent radicles in addition to the nitro-group, this law seems to be partially abrogated in favour of a tendency leading to the production of the di-para-compound. Thus, nitro-p-dichlorobenzene undergoes further nitration in accordance with the following scheme : c1 The mixture of diamines, obtained by reducing the crude nitration product, is fractionally crystallised from water, the chief constituent, 2 : 5-dichloro-p-phenylenediamine, being almost insoluble in this medium, whilst the isomeric base, 2 : 5-dichloro-m-phenylenediamine, readily dis- solves in the hot solvent.The latter base is shown to be a meta-diamine by giving, with acetic anhydride, a diacetyl derivative, whereas an ortho-diamine would furnish an anhy dro-base ; moreover, it readily yields azo-compounds and does not condense with phenant hraquinone to form an azine.The action of diazo-compounds on the isomeric 4 : 6-dichloro-rn-phenyl- enediamine has already been investigated (this vol., 97), but an azo-compound, produced by condensation with a simple diazonium salt, has not hitherto been isolated. Combination has now been effected by operating with p-nitrobenzenediazonium chloride in alcoholic solution. Under these conditions, p-nitrobenxene-2-axo-4 : 6-dichlo~o-m-phenylene- diarnine is produced; the yield of azo-compound, however, is not quan- titative, but comparable in amount with that obtained from other disubstituted m-diamines of the series IT. There can be little doubt that the property of forming o-azo-com- pounds is common to all aromatic primary m-diamines having the general formula IV, although experiments made on tetramethyl-4 : 6- diamino-m-xylene tend t o show that this capacity for condensation with diazo-compounds is lost when the bases are completely alkylated (this vol., i, 656). The tendency for the diazo-radicle t o enter the ortho-position with1380 MORGAN: INFLUENCE OF SUBSTITUTION ON THE respect t o the aminic nitrogen atoms may manifest itself even when one of the reactive para-positions is unsubstituted. Noelting and Thesmar (Zoc.cit.) have shown that this occurs when benzenediazonium chloride interacts with 3 : 5-diamino-o-xylene, the product consisting of a mixture of benzene-6-azo-3 : 5-diamino-o-xylene and the o-azo-deriv- ative, benzene-4-azo-3 : 5-diamino-o-xylene. An attempt was made to prepare a disazo-compound of tolylene- 2 : 4-diamine containing one of the azo-complexes in the position con- tiguous to the two aminic nitrogen atoms by treating p-bromobenxene- 5-axotolyleme-2 : 4-diamine with p-nitro benzenediazonium chloride i n alcoholic solution ; the experiment, however, was unsuccessful, the products being ill-defined and tarry.EXPERIMENTAL. I. Diaxoarnines from 1-Ch Zoi.o-P-nccphthyZamine. 0- Nttrobenxene-2-diaxoamino- 1 -chloronaphthalene, NO, C,H,N,*NH*CloH,Cl, prepared by slowly adding a glacial acetic acid solution of l-chloro-/3- naphthylamine to a cold dilute hydrochloric "acid solution of o-nitro- benzenediazonium chloride, separates immediately as a light yellow precipitate, even without the addition of sodium acetate, When crys- tallised from benzene, it forms pale yellow leaflets sparingly soluble i n alcohol but dissolving readily in the solvent in the presence of sodium hydroxide to a deep purple solution of its sodium derivative.The diazoamine, when slowly heated, decomposes a t 194', but when more rapidly heated i t remains unchanged below 202-204' : 0.2140 gave 31.3 C.C. moist nitrogen a t 20° and 765 mm. N = 16.84. 0.1564 ,, 0,0682 AgC1. C1= 10.78. 0.1493 ,, 0.0642 AgCI. 01 = 10.64. CI,HI,0,N4C1 requires N = 17.15 ; C1= 10.87 per cent. m-Nit~~benxene-2-diaxoarnino-l-cklorona~~tkalene, produced in pre- cisely the same manner as i t s isomeride, separates from benzene in transparent, yellowish-brown, prismatic crystals, which, when suddenly heated, decompose at 142O, this decomposition taking place at 137' if the temperature is raised very slowly.It should be pointed out that the decomposition temperatures of the diazoamines derived from 1-chloro-P-naphthylamine vary within very wide limits and appear to be considerably influenced by the size of the crystals, the rate of heating, the quantity of the material employed in the determination, and the amount of agitation to which the substance is subjected.FORMATION OF DIAZOAMINES AND AMINOAZO-COMPOUNDS. 1381 The diazoamine is sparingly soluble in alcohol, but dissolves in alcoholic sodium hydroxide to a dark brownish-red solution : 0.2280 gave 33 C.C. moist nitrogen a t 19' and 765 mm. 0.1207 ,, 0.0546 AgC1. C1= 11.19. 0*1726 ,, 0,0773 Ag3l. GI= 11.08. N = 16.80. C,6H110,N,Cl requires N = 17.15 ; C1= 10.87 per cent. Action of Nitrous Acid on 1 -Nitro-P-nap~thyZamine.The solution obtained by adding the calculated amount of sodium nitrite to 3.2 grams of 1 -nitro-P-naphthylamine suspended in alcoholic hydrochloric acid was treated with 3.5 grams of l-chloro-P-naphthyl- amine dissolved in glacial acetic acid; the mixture assumed a dark orange colour and a yellowish-brown precipitate rapidly separated. Water was added to complete the separation of the insoluble product ; the latter was collected, dried, and extracted with small quantities of warm alcohol in order to remove any uncombined bases, the residue being then crystallised from benzene. The crystalline product con- sisted of 2-diazoamino-1-chloronaphthalene, which separated in orange- yellow needles decomposing at temperatures varying from 145-1 59' according to the rate of heating : 0.1708 gave 17 C.C. moist nitrogen at 19' and 768 mm.0.1154 ,, 0.0862 AgC1. C1= 18.47. The final benzene mother liquors gave a further crop of crystals of 0.0916 gave 9.5 C.C. moist nitrogen at 1 8 O and 758 mm. N = 11.94. Hence the only diazoamine produced in the above condensation is due to the interaction of a 1-chloronaphthalene-2-diazonium salt on 1-chloro-P-naphthylamine. The oily residue, obtained by evaporating the alcoholic extract to dryness, became solid on treatment with acetic anhydride, and the product, when crystallised from hot water containing animal charcoal, separated in felted, white, silky needles melting at 148O, the melting point of 1-chloroaceto-P-naphthalide being 147'.The aqueous filtrate from the crude diazoamine was poured into a cold alkaline solution of P-naphthol, the resulting azo-derivative being crystallised from ethyl acetate. After one crystallisation from this solvent, the azo-compound, l-chloronaphthalene-2-a~o-~-~ap~t~oZ, was obtained in a state of purity : N = 8-43, N= 11.52. C,,Hl,N,C12 requires N = 11.47 ; C1= 19 -39 per cent. this compound, identified by the following analysis : The yield of the product is 5 grams. 0.1472 gave 10.7 C.C. moist nitrogen at 1 8 O and 763 mm. 0.0963 ,, 0.0410 AgC1. C1= 10.67. VOL. LXXXI 4 2 C,,H,,ON,Cl requires N = 8.42 ; C1= 10.67 per cent.1382 MORGAN : INFLUENCE OF SUBSTITUTION ON THE This compound crystallises in dark red prisms having a brilliant bronzy reflex; i t melts a t 2 3 4 O , is sparingly soluble in alcohol, but dissolves more easily in benzene ; with concentrated sulphuric acid, it develops a beautiful bluish-purpl e colorat ion.The quantities of 1-chloroaceto-P-naph t halide and azo- derivative obtained in the preceding operations amounted to 1 gram and 2 grams respectively, and together with the weight of the diazoamine accounted for practically the whole of the two bases employed in the experiment. The diazo-solution, obtained by adding sodium nitrite to 1-nitro-@ naphthylamine suspended in alcoholic hydrochloric acid, when immediately added t o an alkaline solution of P-naphthol furnished a mixture of azo-compounds giving the following numbers on analysis : 0.1 180 gave 10.4 C.C. moist nitrogen at 18' and 758 mm.N = 10.16. 0.1105 ,, 0.0303 AgCl. C1= 6.78. These results correspond with the composition of a mixture of 60 per cent. of the chloroazo-compound, CloH,Cl*N,*CloHG*OH, with 40 per cent. of the nitroazo-derivative, NO,*C,oH,*N,*C,oH,'OH, derived from the untransformed 1-nitronaphthalene-2-diazonium salt, 11. Action of Diuxonium X n l t s on Dichloro-m-phenylens- diaminss. [With GEORGE M. NORMAN, B.Sc.1 Preparation of 2 : 5-DicTiEoro-rn~~~en~/Ienedia~ine. p-Dichlorobenzene is readily converted into nitro-p-dichlorobenzene on nitration with 1.5 parts of a mixture containing two parts of nitric acid of sp. gr. 1-54 and three parts of concentrated sulphuric acid. After mixing the reagents together at the ordinary temperature, the reaction is finished on the water-bath.The introduction of the second nitro-group is far less readily effected, and even after repeatedly treating nitro-p-dichlorobenzene with a mix- ture of fuming nitric and sulphuric acids on the water-bath the pro- duct consisted almost entirely of the unaltered mononitro-compound. The nitration was, however, accomplished a t 110- 115* by the action of excess of fuming nitric acid mixed with sulphuric acid containing 10-15 per cent. of sulphur trioxide. The crude nitration product was reduced in quantities of 50 grams with 65 grams of iron filings, 6 C.C. of hydrochloric acid and 400 C.C. of water, the operation being completed on the water-bath. The product mas rendered alkaline with sodium hydrogen carbonate and filtered while hot, the precipitate of iron oxide being washed with boiling alcohol.The aqueous filtrates on cooling yielded a crystalline base melting at 83-85' ; this substance, after repeated crystallisation from water, finally melted at 99-100'. In each crystallisation, careFORMATION OF DIAZOAMINES AND AMINOAZO-COMPOUNDS, 1383 was taken t o employ an amount of solvent insufficient to dissolve the whole of the material. The insoluble residue accumulated in this manner melted a t 162-163', being thus identified as p-dichloro-p- phenylenediamine, the melting point of which is given as 164'. The residue obtained on evaporating down the alcoholic extracts consisted principally of the p-diamine. The isomeric base, 2 : 5-dichloro-m-phenylenediamine, melting at 99-1 OOO, crystallises from water in long, colourless, silky needles which become faintly pink on prolonged exposure to the atmosphere : N= 15.85.0,1246 gave 17.4 C.C. moist nitrogen a t 19'and 751 mm. 0.1309 ,, 0,2136 AgCI. Cl=40*36. C,H,N2C12 requires N = 15.82 ; C1= 40.11 per cent. Diacetyl-2 : 5 -&A Zoro-m-phen ylenediamine, C,H2CI 2( NH Ac),, obtained by warming the base with excess of acetic anhydride, separates from alcohol in minute, white needles melting above 260' : 0.0738 gave 0.0803 AgC1. C1= 26.91. C,oHlo02N2CI, requires C1= 27.20 per cent. The benxoyl derivative, prepared by the Schotten-Baumann process, crystallises from ethyl acetate in felted acicular prisms melting a t 220' : 0*0488 gave 0.0374 AgC1. C1= 18-96. C,,Hl,02N2C12 requires C1= 18-44 per cent. p-Nitro6e~xe~eLe-4-~xo-2 : 5-~icliZoro-m-phesiy~~ned~a~~ne, N02*C6H,'N2* C6HC12( NH,),, results from the action of p-nitrobenzenediazonium chloride dissolved in dilute hydrochloric acid on an aqueous solution of 2 : 5-dichloro-m- phenylenediamine containing excess of sodium acetate ; the yield of azo compound is satisfactory, the reaction taking place without appreciable evolution of nitrogen.The product did not crystallise readily from the ordinary solvents, and on this account, and also because of the small amount of material available, it was not obtained in a pure con- dition. It separates from benzene in dark brown, nodular aggregates : N = 20.26. 0*2158 gave 37.7 C.C. moist nitrogen a t 18Oand 763 mm. 0.1454 ,, 0.1388 AgC1. 471-23.61 C12Ho02N5C12 requires N = 21 -47 ; C1= 21.80 per cent.The high percentage of chlorine is probably due t o the presence of a certain amount of the hydrochloride of the azo-compound which re- sisted the action of sodium acetate. The substance melts indefinitely a t 210-230O and develops a deep purple coloration with concentrated sulphuric acid,1384 FORMATION OF DIAZOAMINES AND AMINOAZO-COMPOUNDS. p-~~trobenzene-2-~~0-4 : 6-dichloro-m-phenylenediami~e is iaomeric with the preceding compound and results from the action of a dilute hydro- chloric acid solution of p-nitrobenzenediazonium chloride on an alcoholic solution OF 4 : 6-dichloro-m-phsnylenediamine, these reagents being present in molecular proportion ; it separates as a dark red precipitate and crystallises from ethyl acetate in beautiful dark red needles melt- ing at 258'.The yield of this azo-compound is about 45 per cent. of the theoretical : 0.1454 gave 26.2 C.C. moist nitrogen at 20° and 769 mm. N = 20.90. 0,1314 ,, 0.1148 AgCl. Cl=21*61. C12H,02N5C12 requires N = 21.47 ; Cl = 21.80 per cent. U,H,Br*N2*C6H2(NH2)2*CH,, produced by adding excess of ammonia to a dilute hydrochloric acid solution containing equivalent amounts of p-bromodiazonium chloride and tolylene-2 : 4-diamine, separates as a yellow, ochreous precipitate, and is purified by crystallisation from benzene ; it separates from this solvent in golden-yellow leaflets, and from ethyl acetate or alcohol in reddish-yellow flakes with a golden lustre, the melting point being 0.2055 gave 32.9 C.C. moist nitrogen at 20' and 757 mm. N= 18-22. 0,1571 ,) 0.0988 AgBr. Br=26.70. C13H13N4Br requires N = 18.36 ; Br = 26.23 per cent. If sodium acetate is employed instead of ammonia in the preparation of this azodiamine, a stable, red hydrochloride is precipitated which is not decomposed by excess of the acetate. The yield of the azo- derivative is practically quantitative. p-Bromobe~xene-5-aeoto Zy Zene-2 : 4-dimmim) 1'79-18O0 : p-Bromobenxene-5-ccxo-2 : 4-dimetyltolylene-2 : 4-diamine, C,H,Br N,*C6H2Me(NHAc),, produced by gently warming the azodiamine with a mixture of acetic anhydride and glacial acetic acid, crystallises from alcohol in reddish- yellow leaflets and melts at 228O : 0.2066 gave 26.4 C.C. moist nitrogen at 1 8 O and 750 mm. N = 14.56. C17H,702N,Br requires N = 14-40 per cent. The dibenxoyl derivative, prepared by the Schotten-Baumann process, separates from alcohol in small, ill-defined crystals melting above 250'. ROYAL COLLEGE OF SCIENCE, LONDON. SOUTH EENSINBTON, S. W.

ISSN:0368-1645    

DOI:10.1039/CT9028101376

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

DECOMPOSITION OF NORMAL CUPRIC ACETATE 1385 CXXXIX.-OE>serziatio.ns on the Phenomena and Pq-oducts o f Decomposition when No~rnal Cupric Acetate i s Heated. By ANDREA ANGEL, B.A., Dixon Scholar, and A. VERNON HARUOURT, M.A., F.R.S., Lee’s Reader in Chemistry, of Christ Church, Oxford. Ce me sont pas toujours 2es r6suZtats des opzrations chimiques qui fournissent Ze plus de Zunzikres aux Chimistes-observateura ; l’ezamen des dafzrens ph6nomdjzes qzci accompagnent ces opdrations, est souvent un mogen de saisir des v6ritks fugitives, pour ainsi dire, qu’il aurait %tb impossible d’apercevoir autrement.”* THE changes which verdigris, or cupric acetate, undergoes when heated, attracted the attention of chemists during a long period,? the heating of this salt being in use as a method of preparing concentrated acetic acid.I n 1754, M. de Courtanvaux, happening to rectify on a very cold day some I ‘ radical vinegar ” obtained from Dutch verdigris, observed with surprise the freezing of the distillate. Another winter, eight years later, he repeated this observation, and made others. The first six fractions from a distillation of five pounds of verdigris were successively more dense and more acid, the seventh was more acid but less dense; and, unlike the others, when it was heated it gave off a n inflammable vapour. I n 1773, M. de Lassone observed that the weight of cupric acetate * M. dc Lnssone. Sur les ph6nornhes que presentent la distillation du Verdet t Previous papers on the sawe subject : Courtanvaux, dIemoires d e Z’Acadbmie, 1754. Lassone, Hiptoire de I’Acnd.Boyale dcs Sciences, 1773, 26, and Memoires, 60 ; Chaptal, Annales de Chiinie, 1793, 25, 321 ; 1’198, 28, 113. et du sel drt Saturne (Histoire de 2’Acadhaie Boyale des Sciences, 1773, 20). also Crell, Chem. Jot~wial, 1780, 4, 103. Ad&, ?, ,, 1798, 27, 299. Proust, 2 , ,, 1799, 32, 35. Dnrracq, ,, ,, 1802, 41, 264. Fourcroy, ,, ,, 1802, 42, 225. Proust, Journal dc Physiqw, de Chiwiie, et d’Histoire Natzwdle. Messidor, An. 13. Derosnes, Annales de Chimie, 1807, 63, 267. Mollerat, ,, ,, 1808, 68, 88. Ghenevix, ,, ,, 1809, 69, 1. Gehlen, Schweigger’s Journal fur Cheinia u n d Ph,ysik, 1812, 4, 23. Vogel, Journal de Phannacia, 3815, 1, 339. Berm1 IUS, Poggendorfs Annalen, 1824, 2, 262. Wohler, Lie3ig’s Annnlcn, 1836, 17, 137. ROUX, Revue ScicnliJiqzce et Industr’iclle, 1846, [ii], No.8, p. 5. Foerstw. B ~ T . 1892, 25, 3419. VOL. LXXXI 5 A1386 ANGEL AND HARCOURT : PRODUCTS OF DECOMPOSITION subjected to distillation exceeded that of the liquid product and solid residue, and inferred that some gas had escaped. H e also noticed and described a white, crystalline sublimate, lighter than flowers of zinc, which was a cuprous salt. Between 1798 and 1802, several chemists took part in a controversy as to whether the aeetous acid of vinegar and the acetic acid, or radical vinegar, obtained by the destructive distillation of cupric acetate, were different, as had hitherto been believed, or identical. Chaptal, Fourcroy, and Berthollet supported the old view. Crystallised verdigris was copper acetite.When this substance was heated, there were carbon and copper in the residue. By an elimination of carbon and by taking oxygen which had been in combination with the copper, the acetous acid of the salt was changed into the acetic acid of the distillate. Chaptal also prepared from ordinary vinegar and from radical vinegar two acids of the same density, but differing in their power of neutralising potash and in several other properties. It had not yet been observed that a more and a less dilute acetic acid may have the same density. Adet, Proust, and Darracq maintained and proved the identity of the two acids. Acetous ” acid, distilled with sulphurous acid to preclude oxidation, resembled that from the distillation of copper acetite ” and yielded similar salts.Copper acetate, prepared by saturating radical vinegar with copper oxide, had the same crystalline form, and decom- posed when heated with the same phenomena as copper ;;acetite ” extracted from verdigris. With mercury, lead, iron, and tin, the behaviour of the two acids is the same. Copper ‘‘ acetite ” precipitated by sulphuretted hydrogen gives acetic acid, and here there can have been no oxidation. Distillation of vinegar from calcium chloride yields an acid exactly resembling that from copper acetate, and there is no separation of carbon. Finally, Fourcroy and Berthollet admit that they are convinced. Some years later, 1806--1809, Proust, the brothers Derosnes, Mollerat, and Chenevix made further observations on the distillation of cupric acetate. For shortness’ sake, we will again summarise a group of observations.The white sublimate was observed, but mistaken for dehydrated cupric acetate, About 20 kiIos. of ‘( verdet ” yielded on distillation nearly 10 kilos. of liquid and left a residue, mistaken for copper oxide, weighing 6% kilos. The variations in density of the liquid distillate, which did not correspond to the variations in acidity, and the formation of an inflammable liquid were observed. Soon after, the discovery was made that when acetic acid is progressively diluted with water, the density first increases and then diminishes. The inflammable liquid, called pyroacetic ether or spirit, was acetone. It was well shown by Chenevix that the copper in the residue is metallic copper, and thatWHEN NORMAL CUPRIC ACETATE IS HEATED.1387 it is associated with a small proportion of a black substance which he regarded as carbon. Further observations of these changes were made in 1812 by Gehlen, who showed that the light sublimate was anhydrous cuprous acetate, and that the gases evolved were not hydrogen or hydrocarbons, as previous observers had stated, but consisted of carbon dioxide and carbon monoxide. I n 1815, A. Vogel published fresh observations on the distillation of acetate of copper. He notes, as others had, that the salt decrepitates, and does not fuse in its water of crystallisation. The white crystals which formed in the neck and a t the bottom of the retort he takes to be anhydrous acetate, since in damp air it became of a blue colour; the gas evolved is carbon dioxide mixed with one- fifth its bulk of a hydrocarbon ; the residue consists of copper, cuprous oxide, and carbon. I n 1824, Berzelius observed that when verdigris is gradually heated there is obtained a t a certain period a white sublimate which fills the body of the retort with a light, woolly crystal- lisation.He states that this substance is cuprous acetate, and that it did not change on exposure to moist air. Attempts made by him and by previous observers to produce the same substance by the reduction of cupric acetate with copper were unsuccessful. The last observations we have found were made by Roux in 1846. He heated copper acetate in an open tube, the loweia part of which was plunged in a bath of fusible alloy. Up to 140°, water with but little acid was given off.He gives also the temperatures a t which acetic acid is formed and a t which the white sublimate and the gaseous pro- ducts appear; these temperatures are much higher than the tempera- tures a t which such changes occur when heat is applied very slowly and the substance is in a vacuum. To the many sets of observations of which a summary has been given, containing much that is contradictory and not much that is quantitative, the authors have added another, which, though still incomplete, will, they hope, add materially to our insight into a change of an interesting but very complex character, and contribute some useful suggestions of apparatus and methods for the prosecution of similar inquiries. When a few crystals of normal cupric acetate, Cu(C,K$I,),,H&I- (prepared from the commercial salt by recrystallisation of a hot aqueous solution acidified with acetic acid), are heated in a test-tube, acetic acid is given off and condenses on the walls of the tube, copious brown fumes are evolved, and a bright, continuous, metallic coating of copper is deposited on the bottom and sides of the tube.As the coat- ing is produced where the salt is not in immediate contact with the glass, i t must be deposited from some volatile compound containing copper, The nature of this volatile compound was first investigated. 5 A 21388 ANGEL AND HARCOURT : PRODUCTS OF DECOMPOSITION For this purpose, some of the salt was pIaced in a porcelain boat in a horizontal glass tube, which was connected through a smaller tube, in which a bulb had been blown, with a second similar tube.The bulb was filled with cotton wool. The tube containing the boat was gradually heated, and the second tube, through which any gaseous products would pass, was kept a t a temperature a little below a red-heat. To exclude air, hydrogen was passed slowly through the apparatus during the heating. LYhen the salt was heated, moisture was evolved and a slight, copper-coloured mirror, which did not after- wards increase, was formed in the heated part of the second tube. The coctents of the boat became partially white, and a white deposit was observed above the boat on the tube. When this white deposit was heated, it WAS destroyed and a deposit of copper appeared on the glass tube. No brown fumes were evolved.It appeared probable from this that the white substance was a volatile copper compound ; that the slight mirror at first formed was due to the decomposition of a little of the compound which was carried forward, and that the non-increase of the coppery mirror might be due t o the cotton-wool becoming wet with acetic acid and thus decomposing the sublimate and preventing it travelling forward. I n a second experiment, the salt was heated gradually up to the boil- ing point of water, but no change in its appearance could be noted ; on heating it to a higher temperature in an air-bath while dry hydro- gen was passed over it, the white deposit was again observed, and in this case it was distinctly crystalline. The temperature of the bath when the white substance appeared was 195-200°.In a subsequent experiment, in which the temperature was raised more gradually, sublimation commenced at 173". I n these experiments, only small quantities OF the white substance were obtained, and transmission of steam and of the vapour of acetic acid caused no increase. The bebaviour of the salt when heated in a vacuous tube was next investigated. A tube of the shape shown in Fig, 1 (p. 1389) was made, and the lower compartment filled with the salt. The ap- paratus was then exhausted by means of a Sprengel pump, arid the small tube by which the pump had been attached was drawn off and sealed. The tube containing the salt was then immersed, as shown, in a bath of melted paraffin (Fig. 2, p. 1389). The side-tube and bulb were to collect the liquid given off, the bulb being immersed in a dish of cold water to promote condensation. With this apparatus, no change was observed up to 130°, when a little liquid collected in the bulb.The next change noticed was a slight coppering of the faces of the crystals, which occurred at about 195O. The temperature was allowed to rise fairly quickly ; at 235O, the copper-WHEN NORMAL CUPRIC ACETATE IS HEATED. 1389 ing appeared to be slightly redder, especially on the parts of the salt touching the sides of the glass. No further change was noted until 245O, when the salt appeared dull and paler. The redness had not increased or spread to any portion not in contact with the glass. At 2 4 6 O , a sublimate appeared for the first time on the top of the crystals.The red patches disappeared (possibly owing to their being coated over with the white substance), and t,he whole of the salt lost its blue tint and became of a warm grey colour. Liquid continued to distil over, and no other change mas noted until 260°, when some very small, glittering, crystalline particles appeared which disappeared again FIG. 2. n FIG. 1. at 273*. The top of the upper compartment of the apparatus had in the meantime become coated with sublimate, but this was washed down from time to time by condensed liquid; finally, however, the distillation of liquid ceased, and the top of the apparatus remained coated with sublimate. The whole of the substance in the lower bulb appeared of a chocolate-brown colour. After allowing the apparatus to cool, it was divided into three parts by sealing off a t the side tube and in the middle.On heating the tube to seal off, the softened glass blew out, showing that a volume of fixed gas in excess of the capacity of the tube had been formed.1390 ANGEL AND HARCOURT : PRODUCTS OF DECOMPOSITION To investigate these products, and in particular to collect the gases formed and to prevent contact between the liquids which are condensed and the sublimate, a different form of apparatus was needed. The form which was finally adopted may be seen by reference to Fig. 3 (p. 1391). Description, of Apparatus shown in Fig. 3. The tube in which the salt is heated is divided into two com- partments, A and U, by a constriction, in which a small bulb, H, is placed, to prevent the salt falling down into the lower or sublimate chamber, U.The sublimate chamber is drawn out below into a narrow tube, bent as shown, J, and terminating in a capillary point, P. The tube is fixed by means of a rubber cork, W, into a wider tube, B. The tube B is filled with oil, and is heated by means of a ring-burner cpnsisting of a series of hard, glass tubes, 2, seven in number, of the shape shown in the figure, which allows of their being set close to, or furtber from, the tube B. The burner tubes fit into a wide glass chamber, I , which is supplied with gas by an inlet tube, T'. The gas, after a preliminary regulation by a gas-governor, passes through the regulator, F, before entering the inlet tube T. This regulator, P, allows of the temperature being kept con- stant for a long time at any desired point.For this purpose, the temperature is set approximately by taking out or putting in oil a t x, and the final adjustment is made by raising or lowering the fine tube A' ; a pin hole, B' in A', acts as a by-pzss when trhe expansion of the oil in B raises the mercury in the regulator up to the end of the tube A', andsoprevents the burners from being put out. By this vertical arrange- ment of the tube in the oil-bath, different zones of temperature are ob- tained, the object of which is to allow the sublimate to condense at a point where the temperature is still sufficiently high to prevent the acetic acid condensing also. Below the level of the burner-tips, the temperature of the sublimate chamber falls off rapidly, and the acetic acid and water condense at the bottom, apart from the sublimate, and flow down into the drawn out tube and thence into the washing bulbs.The tube B is supported by a clamp (not shown in the figure) at the narrow portion of the neck, below the two side tubes X and Y. D and D' are two semicircular sheets of tin plate, partly shutting in the space enclosed by the wide, outer glass cylinder, C, which keeps up the temperature and prevents a draught from disturbing the flames. A thermometer, G, registers the temperature of the bath. 3 is a plate of mica to act as a shield. The drawn out tube, J, is fitted by a gas-tight mercury joint (shown in section in Fig 4, about its actual size), so that the capillary tube, V, delivers the liquid freely from its point into the tube of the washingWHEN NORMAL CUPRIC ACETATE IS HEATED, 13911392 ANGEL AND HARCOURT : PRODUCTS OF DECOMPOSITION bulbs, R.The washing bulbs, B, are six in numtw, and are so arranged that when held by one end there is a continual fall fro= the first t o the last bulb,so that they may be conveniently washed out. The three bottom bends form three points of a triangle, and allow of the bulbs standing on the balance pan or any flat surface without support. The bulbs are chwged with water (3 or 4 C.C. in each pair), rather less being placed in the pair of bulbs nearest the capillary, as the main quantity of acetic acid and water from the decomposition of the salt is arrested there. By keeping the three portions of water separate, the washing is made much wore complete, since only that portion of the acetic acid vapour which escapes from the first pair of bulbs after the water in it is nearly saturated passes into the second pair, and only the residue of this into the third pair.The result is that practically the whole OF the acetic acid is stopped, whereas this is not the case if the three portions of liquid are in communication. To prevent the distillation of liquid which is apt to occur when the vacuum is good and the atmosphere moderately warm, the bulbs are enclosed in a bath of ice and water which is wrapped round in cotton wool, P. AS the contact of the glass of the bulbs with the zinc of the bath, 0, has sometimes caused fracture, some folds of flannel, &, are placed on the bottom of the bath.The bulbs are connected by another mercury joint, L, with a drying tube, S, containing pumice moistened with sulphuric acid in the upper part and sulphuric acid in the lower. The drying tube, 8, is connected by another mercury joint, M, with the Sprengel pump by which the gases are drawn off and collected. The washing bulbs and drying tube are of a form convenient for weighing. The Action of Heat on Copper Acetate. The first result of the action of heat on the salt is a forms- tion of liquid. With the apparatus described, i t is somewhat difficult t o determine exactly the temperature at which this occurs, but in one experiment i t was observed at 1 1 5 O . When the tempera- ture has reached 150--160°, the surface of the salt appears coppered in parts. This coppering occurs also when the salt is heated in carbon dioxide or hydrogen. It appears on the parts of the salt immediately touching the glass, and spreads somewhat irregularly over the surface of the salt, but never becomes uniform over the entire sur- face.The coppery deposit appears a long time before any trace of sublimate is seen, and occurs whether the salt is powdered or in crystals; i n the latter case, however, the smooth surfaces of the crystals give the coppering a more metallic appearance. The next noteworthy change is the deposition of sublimate and theWHEN NORMAL CUPRIC ACETATE IS HEATED. 1393 evolution of gas. These two changes occur together, and the tempera- ture a t which they occur is about 230'. In some experiments, the sub- limate has been observed at 215", and in others lower than this.The formation of sublimate ip, however, so extremely slow that a com- plete experiment at these lower temperatures is impracticable. I n one instance, the experiment was continued for a, week and the tempera- ture kept below 312' the whole time ; it was afterwards found t h a t the decomposition was even then incomplete, and on reheating the residue a t a higher temperature a small additional sublimation occurred. For this reason, in the later experiments, the temperature was allowed t o rise fairly rapidly t o 230°, at which temperature the decomposition can be completed in st reasonable time. When about 8 grams of salt are used and the gas is pumped out at a convenient rate, the experiment can be completed in about 9; hours after the appearance of the sublimate.If the pressure of the gases is allowed to rise, the decomposition is retarded. The sublimate always appears at a point in the sublimate chamber just below the level of the tips of the burners, and spreads down- wards. At this part, there is a very steep gradient of temperature. I n one experiment, the temperatures of the extreme limits within which sublimate was being deposited were approximately determined by raising and lowering the thermometer. At the lower limit of the sublimate, the temperature was 103", and at the upper limit 170'; the width of this zone was only 8 or 10 mm. The first portions of the sublimate are almost invariably crystalline; as sublimation becomes more rapid, its appearance changes : i t becomes grBPuular and nodular, growing out from the sides of the tube until a cake is formed a t the top by the sublimate meeting in the centre.After this cake is formed, the sublimate increases upwards slightly, but only for a very short distance. After a time, the bottom of the deposit gradually becomes moist thraugh a condensation of acetic acid, and a green band is formed which spreads slowly upwards. Finally, if the experiment is prolonged, the top of the sublimate becomes of a darker colour. Condensation of liquid and evolution of gas go on more and more slowly, and finally the decomposition comes t o an end, and all that remains of the salt is a reddish-brown residue in the top chamber. The drawn out tube, J (Fig. 3), is then sealed off, the burner extinguished, and the apparatus allowed to cool.After the tube has been removed from the oil-bath, the chambers A and U (Fig. 3) are separated by sealing off. The following tables give the results of the experiments so far as the amounts of the different products obtained are concerned ; after- wards the different products are dealt with separately :1394 ANGIIL AND HARCOURT : PRODUCTS OF DECOMPOSITION 1 Experiment 32. Experiment 34. /I Experiment 35. Salt grams. taken, in l 11- 10'5094. Pef::!t' 8'5886. Residue ..................... Sublimate ................. Acetic acid .................. Water -I- a trace of acet- one ........................ Carbon dioxide ............ Carbon monoxide ......... 1-1-11- 3 '4628 0'3581 4.807 O*7712i 0.8935 0.1526 32.95 3'41 45.73 7'34 8.50 1'45 I 2'7904 0.3616 1 3-5960 0.6331 0.7333 0.1235 I-I-//- Total ..................110.4452 I 99.38 ij 8,5979 I Per cent 100. 32.49 4.21 46.04 7 -40 8 *54 1.44 100*12 8.7741. 2.9221 0.2247 4.069 0 -6637 D-7822 0.1142 8 -7759 Per cent. 100. 33.31 2.56 46'38 7.57 8.91 1-30 100'03 * The amount of acetone formed in thi$ experiment was found to be 0'0013 gram, or 0.01 per cent. The Cases from Copper Acetats heated in a Vacuum. Although many chemists have observed the evolution of gas which occurs when cupric acetate is heated, no two of them agree as to the composition of the gaseous mixture. Thus, Gehlen finds the mixture to be 6 vols. of carbon dioxide and 5 vols. of carbon monoxide ; Vogel, 4 vols. of carbon dioxide and 1 vol. of carburetted hydrogen; Roux, a mixture of carbon dioxide and a combustible gas; Chenevix, 2 vols.of carbon dioxide and 3 of hydrocarbon, In the present experiments, the gases collected after washing with water consisted only of carbon dioxide and carbon monoxide, approxi- mately 4 volumes of the former to 1 of the la4tter. I n some of the earlier experiments, it was found that the gases contained some acetic acid vapour, which had to be washed out before they were analysed. When the last form of washing bulbs (shown in Fig. 3) was used, the acetic acid was completely stopped. As none of the chemists above-mentioned washed the gases with water, it is probable that some acetic acid vapour was mixed with the permanent gases and consti- tuted the '( hydrocarbon " which several mention.The gas was collected over mercury a t the exit of the Sprengel.pump in tubes holding about 40 C.C. The amount of carbon dioxide was estimated by absorption with potash and the residue exploded with an excess of oxygen. A second absorption by potash and, in some cases, an estimation of the residual oxygen by absorption with pyrogallol or explosion with hydrogen, completed the analysis. We found, as others must, that when the The method of analysis was as follows.WEEN NORMAL CUPRIC ACETATE IS HEATED, 1395 Portion XI, 32 : Taken for analysis.. . . . . . . Carbon dioxide , . . . . , . . , , . . Carbon monoxide . , . . ,. . . . gas in which oxygen is to be estimated by pyrogallol is unmixed oxygen, the potash used must be very strong. I n some cases, one portion of gas was divided into two parts and each half analysed separately.Portion XI, Expt. 32, and Portion TI, Expt. 34, were treated in this way, and the numbers obtained were : 45 -05 34 $1 10 '39 44.90 First part. Portion 11, 34 : Taken for analysis ... . , , . . . Carbon dioxide .,. ... . . . , , . Carbon monoxide .. , .. . . . . 42.67 35.51 7-00 I Second part. 47.50 36 -41 10.93 47'34 -- 51.64 42.93 8'46 51 '39 First, per cent. 100 76 d60 23.06 99'66 100 83-22 16-42 99.64 Second, per cent. 100 76-65 23-01 99'66 - 100 83-16 16-39 99.55 A table is given on p. 1396 which shows the results of the ana- lyses of the gases from different experiments, from which it mill be seen that the mean ratio 30, : GO is approximately 4 : 1, that in the first portions of gas collected the proportion of carbon dioxide is in- variably greater than this, and that it then diminishes as the decom- position of the salt proceeds.The temperature of the salt was kept within a degree or two of 230° and the pressure of gases upon it at 2 or 3 CM. The time required for the collection of each portion of gas was about three-quarters of an hour. The evolution was rather more rapid at the beginning and showed a sudden decrease a t the end. I n most cases, the gas was collected under as low a pressure as pos- sible. It was found inexpedient to reduce the pressure below about a couple of centimetres of mercury, because water then evaporated quickly from the washing-tube into the sulphuric acid drying-tube and there was a danger of sulphuric acid spirting back into the bulbs, I n Expt.35, an attempt was made, by collecting the gases at different pressures, 113, 2/3, &c., of an atmosphere, to see whether the pressure influenced the ratio of carbon dioxide to carbon monoxide. It was found that a t the higher pressures the proportion of carbon dioxide was slightly increased.l L - 6 6 ......... I ~ ? O ; L - .................. oz.ol 03 .................. 08,68 z03 71 *aidrum 30 'ON €6.66 49.81 92.18 66-61 10.08 09-81: 9P. 18 13. oz 96.84 16-91 60.E8 'XI ' I I I A 'A 'A1 '111 'IX I 'X ''32 *Lax3 h 0 .. E-c ffi cg c3 mWHEN NORMAL CUPRIC ACETATE IS HEATED. 1397 As the gas formed and collected consecutively in separate tubes had been found to consist wholly of carbon dioxide and carbon monoxide, in the later experiments only a few complete analyses were made, and in most cases the carbor, dioxide was absorbed and the residue taken t o be carbon monoxide.Where, in the tables, the numbers wouldadd up to 100 exactly and the spaces have been left blank, the carbon monoxide was determined by difference. I n Expt. 30, the analysis was made, during the repair of the gas analysis apparatus, by absorbing and weighing the carbon dioxide present, passing the rest through a tube over red hot copper oxide, and absorbing and weighing the carbon dioxide produced. It will be seen that the differences in the proportion of the two gases, in portions collected successively, far exceed the differences shown by two analyses of the same portion. There are, therefore, a t least two changes, of which the gases are products, whose relative rates vary slightly as the decomposition of the salt proceeds, but are not greatly affected by changes of temperature or pressure.The Lipid Products. The liquid products of the decomposition of normal copper acetate at a gradually increasing temperature are water, acetic acid, and a trace of acetone. The amount of acetone found in these experi- ments is extremely small, for example, in Expt. 32, it was 0.01 per cent. With some other acetates, for example, lead and calcium, acetone is the principal product, and some previous observers, working on a large scale, have obtained acetone from copper acetate. The brothers Derosnes, using more than 20 kilograms of the salt, got several ounces of acetone. The cause of the difference would seem to be that in distillations on a large scale substances produced a t a lower temperature come into contact subsequently with the sides of the re- tort and with other substances at a much higher temperature, and thus secondary changes occur.This complication is avoided when we work with small quantities and raise the temperature very gradually. I n the present experiments, it has been noticed that if the experiment is prolonged the top of the sublimate becomes discoloured, and if greatly prolonged, some of it is destroyed and a coppery deposit is formed on the sides of the sublimate chamber. I n a good experiment, the amount of this decomposition is very small, and is probably com- parable in amount with the trace of acetone formed.If the acetone were a primary product of the decomposition of the cupric acetate, it would not be formed in such very small quantities. If, however, it is a product of the decomposition of the sublimed cuprous acetate, which is itself only a small product of the reaction and is only_desomposed1398 ANGEL AND HARCOURT : PRODUCTS OF DECOMPOSITION to a small extent, the minute amount of acetone formed is accounted for. Cu,(W,H,O,), == C,H,O + Cu,O + CO,. A possible equation is : Estimation of Water, Acid, and Acetone. After the washing-bulbs had been weighed, they were emptied and washed, the liquid was made up to a known volume, and a portion taken for titration with standard alkali. The acetone was estimated in another portion by Messinger’s method, which depends on the conversion of the acetone into iodo- form by a standard solution of iodine in presence of potash solution, and estimation of the residual iodine by standard sodium thiosulphate and starch.Three molecules of iodine are required to convert one molecule of acetone into iodoform. The method was first tested with known quantities of acetone and found to be satisfactory, The water was estimated by difference. The Xublimate. The white substance, here called the sublimate, has been known for a long time as a product of this decomposition. Originally described as ‘‘ flowers of copper ” it was afterwards found to be cuprous acetate. The small amount of it formed (1/1280 of the amount of the salt decomposed is given as the quantity by Lassone) has, however, hitherto prevented any analysis of it being made.The amount obtained varies in different experiments ; the largest amount obtained in these experi- ments was 4.21 per cent. (Expt. 34). Also i t is very easily decomposed. As ordinarily prepared, by heating cupric acetate, it is apt to contain traces of acetic acid, and this causes it to turn green when exposed to the air; if it is free from acetic acid, it is fairly permanent, Water turns it yellow, forming cuprous oxide or hydroxide. When it is obtained by heating the salt in a tube through which hydrogen is passed, it forms beautiful, transparent, leafy crystals, and the first portion that appears when the salt is heated in a vacuum is always crystalline. I t can be resublimed in a current of gas (hydrogen, carbon monoxide, &c.), but decomposes on strong heating, leaving a coppery deposit.The sublimate chamber, after being sealed off, was cleansed from all traces of oil. A file mark was then made near one end and a crack led nearly round it, so a s t o allow air to enter slowly. After the sir had entered, it was weighed. The tube was then parted at the crack and the contents washed out into a porcelain dish. The sublimate resisted the action of the water for a short t h e (it was not very easily wetted by water) The analysis of the sublimate was made as follows.WHEN NORMAL CUPRIC ACETATE IS HEATED, 1399 and then turned orange and red and also partly green. As the sublim- ate could not be who1Iy:removed from the glass by water, a little dilute hydrochloric acid was used to dissolve i t off.After having been washed and dried, the tube was weighed, the difference giving the amount of sublimate taken for analysis. As the amount of sublimate was small, not more than 0.2 to 0.3 gram, the whole of it was generally used for an estimation of the copper. A little nitric acid was added to produce the cupric salt and the liquid diluted and heated to boiling. The copper was precipitated with caustic soda and estimated as copper oxide. Two determinations of different samples gave 52-15 per cent. and 51.57 per cent. of copper respectively, the theoretical amount in cuprods acetate, Cu,(C,H,O,),, being 51 5'8. Fhe Residue. The residue is a soft, light, reddish-brown powder. When crystals of the salt have been heated, they retain their form more or less in the residue.Under a magnifying glass, numerous glittering particles can be seen, and if one of the little nodules of the residue is pressed with a spatula, on a flat surface so 8s to crush it, it is seen to consist, in addition to the small metallic specks, of a brown- ish-black, amorphous substance resembling some form of carbon. If the residue is powdered and then washed with a stream of water, a partial separation of the metallic particles from the carbonaceous material can be effected. This separation, however, is not complete enough for analysis. When ignited in a crucible open to the air, the carbonaceous mate- rial glows and burns away, while the copper is converted into copper oxide. The copper appears t o be entirely in the metallic state, and is only mechanically mixed with the carbonaceous matter.The residue amounts almost exactly to one-third of the salt taken. It varies, how- ever, slightly in amount in different preparations, and this variation is connected with the variation in the amount of sublimate obtained; the greater the amount of sublimate, the less is the amount of residue, as may be seen by reference to the table of the results of experiments 32, 34, and 35. Although this residue has often been examined, and is stated to con- tain copper, cuprous and cupric oxides, and carbon, no analyses of it have been given beyond a statement of the percentage of a substance '' which had all the properties of carbon." It was hoped to determine the composition of this substance by a combustion.It was found, however, that in no case did the amount of carbon, obtained as carbon dioxide, suffice t o make up with the copper the full amount of sub- stance taken ; alsoa little water wasalways formed. The black substance1400 ANGEL AND HARCOURT : PRODUCTS OF DECOMPOSITlON must therefore contain oxygen and hydrogen as well as carbon. The numbers obtained in the combnstions were : Copper. Carbon. Hydrogen. Oxygen by diff. Total. Expt. 32 ...... 90.39 6.02 0.237 3'353 100 Expt. 34 ...... 90.14 5.s3 0.30 3.73 100 Expt. 35 ...... 91.58 6.00 0.2 1 2.2 I 100 It was noticed during the combustion in Expt. 34 that moisture appeared in the calcium chloride tube before there waa any sign of carbon dioxide, and before the substance, which was placed in a porce- lain boat, had begun to glow.This pointed to the substance contain- ing moisture, and on trial it was found to be hygroscopic and to lose weight over sulphuric acid. When a little of the residue was placed on blue litmus paper and moistened with distilled water, a red spot appeared. The black substance is slightly soluble and may have an acid reaction, or it may have retaitied or recovered from the contents of the nearly vacuous tube a little water and acetic acid. Carbon dioxide, being one of the products of the reaction, seemed n suitable gas to employ for passing over the residue t o assist in removing whatever is volatile. Accordingly, in order t o prepare some quantity of the residue and examine the carbonaceous material, an experiment was made on a larger scale, in which about 46 grams of the salt were taken instead of the usual 5 or 10 grams, and dry carbon dioxide was passed through during the whole of the heating, which wa8 continued during three days; the residue obtained had the usual appearance.Dilute nitric acid of semi-norma1 strength was employed to extract the copper. The results showed that the extraction was complete, After the usual washing and drying, the substance was placed in a porcelain boat within a glass tube heated to 105' and a stream of dry air was passed over i t for five hours. The combustion still showed deposition of water before the substance began to burn visibly. There was no residue of cupric oxide i n the boat, or sublimate in the combustion tube above. The presence of a little water would throw the carbon too low, and the hydrogen and oxygen too high; in view of this, the formula which best represents the com- position of the substance is C1,H,O,: Found C = 65.30 ; H = 2.1 1 ; 0 = 32.59 per cent.C,,H,O, requires C = 65.99 ; H = 2.01 ; 0 = 32.00 ,, That water is given off before a compound of carbon, hydrogen, and oxygen enters into visible combustion is, of course, no evidence that the hydrogen and oxygen which form the water were not constituents of the substance. If, howevor, it be assumed that all the waterWHEN NORMAL CUPRIC ACETATE IS HEATED. 1401 Total ............... In 100 of CU(C,H~O~)~,H,O collected in the combustion was attached as water to the actual substance, and the mess taken for combustion be reduced accordingly, there remains, as the actual substance, a compoiind of carbon and oxygen of which the most probable formula is C1,O, : Found C = 80.56 ; 0 = 19.44 per cent. Cl,O, requires C = 80.50 ; 0 = 19.50 ,, The composition of the residue may also be arrived at by subtracting from the quantities of copper, carbon, oxygen, and hydrogen in the copper acetate originally taken, the quantities of each element in all the volatile products. It will be seen that the composition thus calculated accords well with the results of analysis, leaving no doubt that the black Substance, which, in admixture with metallic copper, forms the residue after prolonged heating of the salt in a vacuum, contains a considerable amount of oxygen. 1-75 31.78 Experiments 34 and 35. Masses of each eIement from 100 of Cu(C,H,O,),,H,O. Hence, in residue ............ Jn residue, by analysis ...... (Mean of Expts. 34 and 35) 1 Copper. 30'03 29.9 2'18 In sublimate ............... {I .33 In water .................... - ......... {I - In carbon dioxide In carbon monoxide ...... -I Sum of two experiments (to be divided by 2) 1 3'51 I Carbon. 0 -82 0'5 18-42 18'55 - - 2-33 2 '43 0 '62 0 '56 44-23 22.11 24'06 1.95 1 '94 Hydrogen. 0'10 0 '06 3 *07 3 '09 0.82 0.84 - - - - 7.98 3.99 4*04 0.05 0 *08 Oxygen. 1.10 0.67 24'55 24'73 6.58 6'72 6'21 6 '48 0.82 0 '74 78'60 39-30 40'11 0.81 0 '98 The excess of oxygen and hydrogen in the composition of the residue VOL. LXXXI. 5 B1402 McKENZIE : THE RESOLUTION OF fl-HYDROXYBUTYRIC shown by analysis is doubtless due to the hygroscopic character of the substance and the small quantity available for analysis. The authors hope to make a similar examination of the phenomena and products when copper formate is gradually heated in a vacuum. DR. LEE’S LABORATORY, CHRIST CHURCH, OXFORD.

ISSN:0368-1645    

DOI:10.1039/CT9028101385

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1402 McKENZIE : THE RESOLUTION OF fl-HYDROXYBUTYRIC CXL.-The Resolution of 6-Hydroxybutyrzc Acid into its Optically Active Components. By ALEX. MCKENZIE. OF the three P-hydroxybutyric acids, two have previously been described. The inactive acid was prepared by J. Wislicenus (Annalen, 1869, 149, 205) by the reduction of ethyl acetoacetate with sodium amalgam. The Z-acid is an important biological product discovered by Minkowski (Arch. exp. Path. Pharm., 1884,18,35,14’7) and Eiilz (Zeit. Biol., 1884, 20, 165) in the urine of patients suffering from Diabetes meZZitzts. It is excreted in very large amount, more particularly when the patient is in the coma stage; Magnus-Levy, for instance, who has lately made an exhaustive study of the bearing of this acid on diabetes, cites one case where he found so much as 119 grams in one day.It is not yet known by what process such large quantities are produced in the organism, although it now appears to be established that the acid is not a product of albuminoid decomposition. In this paper, the preparation of the d- and I-acids from the inactive compound is described. The alkaloidal salts formed by the inactive acid are easily soluble in most solvents and are not readily crystal- lisable. Quinine was found to be the most suitable alkaloid for effecting the resolution, the salt of the I-acid being easily crystallisable and less soluble in water than that of the d-acid. 1-Acid. An aqueous solution of inactive P-hydroxybutyric acid (prepared by Wislicenus’ method) was neutralised by heating with 180 grams of quinine, and the clear, syrupy solution (450 c.c.) cooled and sown with a nucleus of the I-acid-Z-quinine salt prepared from the acid obtained from diabetic urine.After remaining for 24 hours a t 7*, the semi-solid mass was separated, and the filtrate, which in the course of three months did not crystallise, was laid aside to be subsequently treated for the isola-ACID INTO ITS OPTICALLY ACTIVE COMPONENTS. 1403 tion of the d-acid. The solid was fractionally crystallised from water. The solutions, when cool, were sown each time with a nucleus of the pure salt and the crystallisations conducted at temperatures varying from 6 O to 8". As the quinine salts of the d- and Z-acids melt within 2" of one another, melting point determinations were of little service as an indication of the progress of the resolution.Further, the difference in optical activity between the two salts is so slight that determinations of [ u ] ~ in successive crops are also of little value. In the special case of this acid, however, the rotation of the naturally- occurring I-isomeride has been accurately determined by Magnus-Levy (Arch. exp. Rath. Pharm,, 1901, 45, 389), so that, when the separation had reached a certain point, portions of successive crops were decom- posed in the manner described below and the rotation of the resulting acid examined. The water of crystallisation was estimated in the air-dried product : C20H2402N,,C,H,0,,4~H20 requires H20 = 15.9 per cent. Sixty grams of the Eacid-kquinine salt were finally obtained.1*1808, at looo, lost 0,1876 H,O. The air-dried salt is much more soluble in hot water than in cold, from which it crystallises in needles grouped in rosettes. It is easily soluble in cold ethyl alcohol and in hot ethyl acetate, moderately so in boiling chloroform, and sparingly so in boiling acetone, ether, benzene, or carbon tetrachloride. The air-dried salt melts indistinctly between 60' and 70"; when deprived of its water of crystallisation, it melts at 124°5-125*50. The specific rotation of the air-dried salt was determined in ethyl alcohol : H,O=15*8. Z=4, ~ ~ 2 . 8 1 4 , - 14*62', [u]F - 129.9". The kacid was prepared from diabetic urine according to Magnus- Levy's method (Zoc. cit.) and was converted into quinine sdt. The latter resembled the above described product in crystalline form, melting point, and rotatory power, the specific rotatory power of the air-dried product being The 60 grams of the quinine salt were dissolved in cold water, decomposed by a slight excess of normal caustic potash solution, and kept at 0" overnight.After removal of the quinine, the filtrate was concentrated and then shaken several times with chloroform to ensure the removal of quinine. After addition of normal sulphuric acid solution equal in amount to the alkali previously added, the P-hydr- oxybutyric acid was extracted with ether in a continuous extraction apparatus. The acid was obtained first of all as a syrup; an aqueous solution, the concentration of which was determined by titration against - 129.0' (c = 2.8052). 5 B 21404 MCKENZIE : THE RESOLUTION OF B-HYDROXYBUTYRIC - 1.62" 2 '87 1 7 5 1'38 normal potassium hydroxide solution with phenolphthalein as indicator gave the following result : 1 = 4, c= 8.3304, ay - 8-31', [ a y - 24.9'.On standing for several months over sulphuric acid in a partial vacuum at about 4O, the syrup solidified. The acid is easily soluble in most of the common solvents and melts at about 45.5-48O. It was found impossible to get the melting point sharper, as the acid is exceedingly hygroscopic. The specific rotation, where the con- centration was estimated by direct weighing, was determined with the following results : - 24.8" 17.5 1 7 5 17-3 Solvent. 1 1. 1 c. Water ........................ ............. Ethyl alcohol.. . . . . . . . . . . . . . .. . . . . , . , . .............. I I 2 3.264 J 9 8.2072 $ 9 4.994 4 1 *9976 t. 2 0" 18 16 The rotation is only slightly affected by the presence of alkaline uranium nitrate (Walden, Ber., 1897, 30, 2859). A solution with c=O*328 gave UF -0.21' (Z=2), whereas for a solution of this con- centration in the absence of the alkaline uranium nitrate, the rotation is calculated to be uD - 0.16' (I = 2). The sodium salt having [a]g - 14.5' (c = 8.518) was analgsed : 0.3430, dried at llOo, gave 0.1963 Na,SO,. C4H,03Na requires Na = 18.3 per cent. For the purpose of obtaining a nucleus of the quinine salt of the I-acid, it has been already mentioned that the acid was prepared from urine by Magnus-Levy's method. The optical activity of the acid so prepared agreed with that recorded by him.Dr. G. A. Finlayson and Dr. J. J. R. Macleod kindly provided specimens of the urine of patients in the coma stage of Diabetes mellitus. In the preparation of the acid, it is convenient to perform the requisite ether extractions in a continuous extraction apparatus. Magnus-Levy found [ a ] F - 24.23' (c=11*0) for the acid and -14.15' (c=7*317) for the sodium salt, water being the solvent in each case. These results accordingly establish the identity of the naturally-occurring acid with the syn- thetical product. The values of the specific rotatory power of the acid as determined by Magnus-Levy and myself are in excess of those by Minkowski and Kulz and are very little altered by changes of temperature and con- Na= 18.6.ACID INTO ITS OPTICALLY ACTIVE COMPONENTS.1405 centration. The solutions do not exhibit the varying rotations observed with other aliphatic hydroxy-acids, such as lactic (Wislicenus), gluconic (Tollens), glyceric (Frankland), and malic (Walden), which are due to strongly active anhydrides. d-Acid. I n the resolution of an inactive acid by an alkaloid, it is often difficult, after removal of the alkaloidal salt of one of the active forms, to isolate the other salt from the mother liquors. Should it be pos- sible, however, in the case of the inactive acid t o find a metallic salt which is a dl-mixture, and not an s*-compound, and which can be readily separated from its solutions by crystallisation, the resolution may be conveniently carried out (compare Marckwald, Ber., 1899, 32, 1089).This could not be done in the present instance, as the majority of the metallic salts of the P-hydroxybutyric acid do not, lend themselves t o separation from their solutions by crystallisation. The silver and cadmium salts were the only two which appeared likely to be suitable, but it was found, by aid OF the well-known criterion of Bakhuis- Roozeboom for distinguishing between a solid dkconglomerate and a solid r-compound, that those salts are r-compounds and not dl-mix- tures. It was found that the d-acid-Z-strychnine salt is less soluble in ethyl acetate than the I-acid-Z-strychnine salt, and the former salt was finally separated, the crystallisation being conducted at first from alcohol and finally frcim ethyl acetate. From the acid with [.)a + 2 - 5 O (c = 17*056), recovered from the quinine mother liquors, the strychnine salt was prepared by digestion with the base in ethyl alcohol solution and allowed to crystallise a t the temperature of the laboratory for several weeks.The result- ing crystalline magma was drained on porous plates and the pro- duct (35 grams) repeatedly cryatallised from anhydrous ethyl acetate. The progress of the resolution was observed by decomposing the filtrates from each successive crystallisation and noting the activity of the acid. I n solutions of similar concentration, the following values for [a], were thus obtained : + 9-6', 109', 13.0°, 14*0°, 1 9 - 7 O , 22*3O, 23*1°, and 24-49 As the [a]= of the Eacid has been found to be 2 4 * 9 O , the strychnine salt was therefore pure after eight crystallisa- tions.It crystallises from ethyl acetate in glassy, rectangular prisms grouped in rosettes, and a solution of the air-dried salt in ethyl alcohol gave [u]Y -33.8' (c= 1.256). The salt begins to decompose at 250°, so that melting point determinations were of no aid as an indication of the progress of the resolution. Recourse was therefore had to the alkaloidal method.1406 McKENZIE : THE RESOLUTION OF P-HYDROXYBUTYRIC The salt was dissolved in water, in which it suffers considerable hydrolytic dissociation, and the acid was prepared from it by the method already described for the I-isomeride. The resulting syrup crystallised immediately on addition of a nucleus of the I-acid. The specific rotation, where the concentration of the dried solid was determined by direct weighing, gave a value agreeing within the limit of experimental error with that of the I-acid, thus : I - 2, c = 2.226, ubw + 1.08', + 24.3'.On analysis, 04452 dissolved in water required 425 C.C. N/10 potassium hydroxide solution for neutralisation. C,H,O, requires 42.8 C.C. for the same amount. The specific rotation of the potassium salt agreed with that of the potassium I-salt. The d-acid-Z-quinine salt crystallises from water in silky, radiating needles. 0.3'717, at looo, lost 0.0153 H,O. The hydrated salt melts at 108-114°, the anhydrous salt at The air-dried salt contains 1H,O which is lost at 100" : H,O = 4.1. C,,H2,0,N,,C,H,0,,H,0 requires H,O = 4.0 per cent. 126.5-1275O. The air-dried salt dissolved in ethyl alcohol gave : Z=2, ~=3*1100, u:' - 7*85', [u]? - 126*2O, a value only slightly lower than that of the I-acid-Z-quinine salt.Both active acids in the form of syrups may be kept for months in a partial vacuum over sulphuric acid without crystallising. A crys- talline nucleus of the I-acid causes immediate crystallisation, not cjnly of the I-syrup, but also of the &syrup ; similarly, a nucleus of the d-acid causes crystallisation of the d-syrup and of the I-syrup. The two active nuclei behave, in fact, as if their crystalline forms are identical, and this is not what would be expected if the idea, originally expressed by Pasteur, is universally correct, namely, that isomerides which in solution exhibit opposite signs of rotation are hemihedric when in the crystalline form. In the light of the observations just mentioned, it was cb p ~ i o r i un- likely that an active nucleus would cause crystallisation of the inactive syrup, a conclusion borne out by experiments on the pure syrup and its concentrated aqueous solutions a t temperatures varying from 30' to that of boiling liquid air.I n this connection, the following experi- ment may also be mentioned. Diacetylracemic anhydride, prepared by acetylating racemic acid by Thiele's method, was obtained as a syrup which, when kept for several hours, did not crystallise until a crystalline nucleus of d-diacetylracemic anhydride was introduced. Crystallisation then gradually proceeded and the solid, withdrawnACID INTO ITS OPTICALLY ACTIVE COMPONENTS. 1407 Sodium salt ............ Potassium salt .........Zinc salt ............... Magnesimz salt ...... long before the crystallisation was complete, proved to be inactive. Comparison may also be made with experiments on mandelic acid (McKenzie, Trans., 1899, '75, 964) where the addition of an active nucleus to a supersaturated solution OP inactive substance yielded inactive products in every case. These negative results were attri- buted to the possibility of hemihedrism being either absent or masked in the active nuclei employed; the d-nucleus had the same effect as the Z-nucleus, the two forms inducing crystallisation as if they were identical in crystalline form. Separation of an optically active product by sowing an active nucleus either into supersaturated solutions or into superfused liquids of the inactive form is quite exceptional, the only cases on record being the experiments of Qernez with sodium ammonium racemate (Compt.rend., 1866, 63, 843), of Purdie with zinc ammonium lactate (Trans., 1893, 63, 1143; Purdie and Wallace Walker, Trans., 1895, 67, 616), and of Ruff with the benzylphenylhydrazones of erythrose (Ber., 1901, 34, 1362). I n the first of these cases, it is known that the hemihedrisrn of the active forms is such as is evident from crystal measurement alone; in the two latter cases, the crystals have not been measured. The following polarimetric observations were made with aqueous solutions of salts of the synthetical Z-acid : 8 518 3.4072 1.3629 4 '3'142 1.7497 22.2125 8'885 3.554 1.4216 14.3937 5.7575 2.303 i c. I - t. 15" 17 $ 9 12 $ 9 18 7 9 I ) ¶ ¶ 13 2 J Y ? - aD.- 4.93" 1 -95 0 *75 1.08 0 *83 7.97 2-93 2-17 0'81 5-15 1 *86 1.41 - 14.5" 14.3 13 -8 12.3 11.9 17 '9 16 *5 15.3 14-2 17'9 16.2 15.3 [ ID* - 18'3" 18'0 17'4 17'5 16.9 24.3 22.4 20'8 19.3 20 *6 18.7 17-6 With aliphatic hydroxy-acids generally, the molecular rotation of the acids varies considerably with concentration and the values for dilute aqueous solutions of the normal salts are very much higher than those for the free acid. The rotations of P-hydroxybutyric acid and its salts are exceptional in this respect. It has already been mentioned that change of concentration has little influence on the value for the specific rotation of the acid, and it will be seen from the1408 MCKENZIE : THE RESOLUTION OF P-HYDROXYBUTYRIC above figures that the salts rotate in the same direction as the acid but to a less degree.There is here no indication of the disturbing effect which the hydroxyl group in other cases is known to exert on optical activity. Consideration of the rotations quoted led to the conclusion that the optical activity of the anhydride of /3-hydroxy- butyric acid cannot differ much from that of the acid. The following experiments proved this to be the case. When inactive P-hydroxybutyric acid is heated a t loo’, it is par- tially converted into an anhydride. In one experiment, for example, where the inactive acid was heated for 30 hours a.t looo, the behaviour of the resulting syrup on titration with alkali was similar t o that ob- served by Wislicenus with lactic acid (Annalen, 1872, 164, 181) ; the amount of alkali required for neutralisation in the cold was very much less than what would have been required on the assumption that the syrup consisted of the acid alone, whilst the solution, which in the cold had been made feebIy alkaline, became acid in reaction, gradually at ordinary temperature, and quickly on boiling.When the kacid is heated at loo’, it suffers partial conversion into an anhydride, which, unlike the anhydrides of lactic and glyceric acids, for instance, rotates in the same direction as the parent acid, but to a less extent. No crotonic acid was observed to be produced at this temperature. 1.1516 grams of the I-acid, a t 100’ for 21 hours, lost 0.0354 gram, and the product, when dissolved in cold water, gave a value for [a], about 4’ helow that of the acid : I = 2, c = 4.4648, UF - 1*S7’, [ u?: - 20.9’.The anhydride present was estimated by the method used by Wis- licenus for lactic acid. In 1.07 grams of the product, the quantity of acid was found to be 0.40 gram, and of anhydride 0.68 gram, on the assumption that the anhydride has the formula CH,* CH( OH)*CH,-CO* 0 CH( CH,) CH,*CO,H.* The constancy of the rotation of the active P-hydroxybutyric acids in aqueous solutions is thus understood. An aqueous solution of the acid may be regarded as containing some anhydride due to the “autocatalysis” brought about by the free acid present (Henry, Zeit. physikal. Chem., 1892, 10, 96), but as the rotation of the anhydride differs so little from that of the acid, a small amount of the former present in the solution cannot be detected by polarimetric observation.In marked contrast to the corresponding salts of active lactic acid, the rotations of the sodium and potassium salts are little influenced by * I t should be mentioned that the heating of the E-acid at 100” does not cause The product, recovered from the potassium salt remaining partial racemisation. from the preciding estimation, had the rotation of the pure 1-acid.ACID INTO ITS OPTICALLY ACTIVE COMPONENTS. 1409 changes of temperature and concentration. As usual, the Landolt- Oudemans law holds good. The ionic molecular rotation cannot be deduced from observations on the acid, which is not suEciently ionised in aqueous solutions having a rotatory power large enough in a 400 mm.tube to permit of determinations from which conclusions might be drawn. The ionic molecular rotation, deduced from the determinations on the salts, has a value of about 17’. The zinc salt shows a distinct variation with concentration, the molecular rotatory power falling with dilution. This can be attributed to the low degree af electrolytic dissociation which zinc salts are known t o exhibit. A notable instance of the influence of this factor on optical activity is afforded by the observation of Purdie and Irvine (Trans., 1901, 79, 962) on the zinc salt of d-dimethoxysuccinic acid, the [MY,” of which varies from - 14.4’ (c = 4.3690) to + 88.4’ (c = 0.546 1). Partial Resolution of P-Hydroxybutyric Acid in, the Living Oqjanism. The first reference to the fate of /I-hydroxybutyric acid in the living organism is by Albertoni (Amh.exp. Path. Phccrtn., 1884, 18, 238), who did not detect acetoacetic acid as a decomposition product. Minkowski (Arch. exp. Path. Phwm., 1893, 31, 182) found in the case of a dog which had been made diabetic by extirpation of the pancreas and then fed per 05 with sodium I-/3-hydroxybutyrate, that the urine gave a strong ferric chloride reaction and likewise the Lieben iodoform test. From this research and from that of Araki (Zeit. physiol. Chem., 1894, 18, l), it was established that P-hydroxybutyric acid is converted in the organism into acetoacetic acid and acetone (compare also Waldvogel, Centr. inn,. Med., 1898, 33, 845 ; Ahrens, Inaug. Dissert. Gottinyen, 1899). With the view of throwing some light on diabetic coma, Stern- berg (Virchow’s Archiv, 1898, 152, 207) examined the action of in- active sodium P-hydroxybutyrate by injecting this salt into the jugular vein of frogs and cats.He was unable to find any P-hydroxybutyric acid in the urine subsequently examined. Likewise, when the acid was taken into the human system per os, the presence of acetone or acetoacetic acid could not be detected. Sternberg concludes that the acid was entirely oxidised. When an inactive resolvable substance is not entirely oxidised in the organism and can be partly recovered from the urine, it seemed probable, in the light of the experiments of Marckwald and McKenzie on the fractional esterification and hydrolysis of stereoisomerides (Ber., 1899, 32, 2130 ; 1900, 33, 208; 1901, 34, 469), that a partial resolu- tion of inactive substance would occur under those conditions.This view received a certain support from Brion’s observation that I-tartaric acid is more rapidly oxidised in the organism than d-tartaric acid1410 MeKENZfE : THE RESOLUTION OF @-HPDROXYBUTYRIC (Zeit. physiolr. Chem,, 1898,25, 283), although in Brion's experiments the problem becomes somewhat complicated from the fact that bacterial influence must be considered, the acids having been given per 0s. Neuberg and Wohlgemuth, on the other hand, have recently found (Zeit. physiol. Chem., 1902, 35, 41) that when r-arabinose is injected into rabbits, either subcutaneously or intravenously (when bacteria can have no influence in resolving the sugar into its active components), a product consisting of r- and d-arabinose is recovered in the urine.The same investigators have also observed that I-arabinose is more readily attacked in the organism than d-arabinose. From two separate experiments in which inactive potassium and sodium P-hydroxybutyrates respectively were injected subcutaneously into dogs, I have found that (I) acetoacetic acid and acetone were present, (2) a small portion of the P-hydroxybutyrates was not attacked, (3) this product was laworotatory. This result indicates that d-P-hydroxybutyrate is more readily decomposed by the organism than the I-isomeride. Twenty-three C.C. of an aqueous solution containing 9 grams of inactive potassium P-hydroxybutgrate were injected subcutaneously into a dog, the urine of which, passed during the 24 hours previous to the injection, had been examined by Magnus-Levy's method and found to contain no P-hydroxybutyric acid.Three hundred and fifty C.C. of urine were collected during the next 36 hours, and in this any bacterial growth had been prevented by the presence of thymol. Ammonium sulphate was added and the product evaporated to a small bulk and filtered. After addition of sulphuric acid, the solution was extracted with ether in a continuous extraction apparatus. Water was added to the residue from which the ether had been evaporated and the solution was filtered from a trace of hippuric acid, The filtrate was next distilled in steam until 100 C.C. of the distillate required less than 0.2 C.C. of N potassium hydroxide solution for neutralisation.Practically no volatile fatty acids were present. The residue, which was strongly acid t o neutral litmus paper but did not turn congo-red paper blue, was neutralised by 6.1 C.C. of N potassium hydroxide solution. The solution of potassium salt, decolorised as far as possible by animal charcoal and evaporated to 12 c.c., gave &' - 0.38O ( I = 2), whence [alD - 2.6'. 0.9 Gram of salt was recovered from the 9 grams used. The acid obtained from the salt was also distinctly lzevorotatory. In a second experiment, made with 7 grams of inactive sodium salt, similar results mere obtained. The urine collected after the injection gave a coloration with ferric chloride solution and also the Lieben iodoform test and a little P-hpdroxybutyric acid with a leevo-rotation was isolated from it. The urine before the injection did not contain acetoacefic acid, acetone, or P-hydroxybutyric acid.The solution ofACID INTO ITS OPTICALLY ACTIVE COMPONENTS. 1411 recovered P-hydroxybutyric acid gave uhp - 0.16’ ( I = 2) and this was converted into sodium salt, which had the rotation u]D9” - 0.12’ (Z = 2). The sodium salt recovered amounted to 0.8 gram. As the injections were made subcutaneously, the partial resolution of the acid into its optically active components- cannot be ascribed to the action of bacteria, and does not fall under the head of either of Pasteur’s methods for resolving inactive substances. The author’s thanks are due to Dr. Allan Macfadyen for performing the injections. The following hypothesis may be advanced to account for the partial resolution described.The d-constituent of the inactive substance combines in the organism with an asymmetric complex (C), the I-con- stituent combines with the same asymmetric complex, but the rate of combination can in each case be different. On the assumption, firstly, that the combination of the inactive acid with C is incomplete, and that the two products (d-acidfC) and (Z-acid + C) are entirely oxidised, it irc obvious that an optically active acid may be obtained. On the assumption, on the other hand, that the combination of the inactive acid with C is complete, and that the two products (d-acid + C ) and (&acid + C) are not entirely oxidised, the oxidation of those products can proceed at different rates, as they are not “Spiegelbilder.” Unequal amounts of (d-acid + C) and (Z-acid + C ) may thus be formed and, by elimination of C, the resulting mixture may contain the 9.- (or dZ-) acid with an excess of the one active stereoisomeride.Other possibilities, for example, where the combination of the inactive acid with C is incomplete, and where (d-acid + C) and (Z-acid + C ) are not entirely oxidised, are more complex and need not be discussed. In order to show that a partial resolution of the acid is possible where the asymmetric complex (C) is a substance of known constitu- tion, experiments with Ementhol and I-borneol were made (compare Marckwald and McKenzie, Zoc. cit,). On account of the tendency of /3-hydroxybutgric acid to pass into crotonic acid, the temperature con- ditions under which the esterifications were conducted had to be kept rather low.The amount of esterification was accordingly slight, but the partial resolution was nevertheless quite marked. 14.6 Grams (1 mol.) of inactive j3-hydroxybutyric acid were heated with 21.9 grams (1 mol.) of Lmenthol a t 100’ for 8 hours. The pro- duct was dissolved in ether, and the unesterified acid removed by ex- traction with an aqueous solution of sodium carbonate. The solution of the sodium salt was completely freed from menthol by extracting it with ether, and then concentrating by evaporation. It was then acidified and extracted with ether. The resulting acid was made up to 25 C.C. with water, and then gave UF - 0*08O (I = 4). The mixture of esters remaining after the removal of the unesterified acid was hydrolysed by alcoholic potash, and, after complete removal of1412 CAIN AND NICOLL: THE RATE OF menthol, the acid was obtained as before. Its aqueous solution, made up to 25 c.c., gave UY + 0.05' ( I = 4). The total acid recovered was found by titration to be 13.2 grams, of which only 1.1 grams had been est erified. The inference from this experiment is that, of the two active acids, the d-isomerids is the more quickly esterified by menthol. When 14.6 grams of the inactive acid were heated with 21.9 of menthol for 3 hours at 130°, 12 grams of unesterified acid were recovered, and this, when made up to 25 C.C. with water, gave &" - 0 - 1 1 O (I= 4). On the other hand, the acid obtained by hydrolysing the mixture of menthyl esters, instead of being dextrorotatory, was practically inactive, a phenomenon which can be ascribed t o partial racemisation, the d-acid- I-menthyl ester and the I-acid-Z-menthyl ester being racemised at different rates. When 8.5 grams of inactive acid were heated with 12.6 grams of Lborneol a t 100' for 10 hours, 6 grams of unesterified acid were recovered. This, when made up to 25 C.C. with water, gave ay - 0.30' ( I = 4). The hydrolysis of the esters yidded 1.1 grams of acid, the aqueous solution of which, made up to 25 c.c., gave ar + 0 * 1 7 O (Z=4). The work described in this paper was carried out by aid of the Grocers' Company's Research Studentship. CHEMICAL DEPARTMENT, JENNER INSTITUTE OF PREVENTIVE MEDICINE, LONDON, S.W.

ISSN:0368-1645    

DOI:10.1039/CT9028101402

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1412 CAIN AND NICOLL: THE RATE OF CXL1.-The Rate of Decomposition of Diazo-compounds. By JOHN CANNELL CAIN and FRANK NICOLL. IN view of the extended use, on the large scale, of aqueous solutions of diazo-salts, it is surprising how little has been published on the subject of their stability. In the manufacture of azo-colours, the diazo-salt is usually ‘; coupled ” very shortly after its preparation, but in the production of the so- called “ice colours ” on the cotton fibre, the solution often has to stand for a considerable length of time. It is therefore of much importance to know the proper conditions under which the solution will remain undecomposed, of which the moat important is the temperature. The chief point of interest, however, lies in the study of the rate of Purt I.Diazo-compounds of the Benzene Series.DECOMPOSITION OF DIAZO-COMPOUNDS. PART I. 1413 decomposition of diazo-salts, and the investigation of this for a number of compounds has been the subject of our work during the past year, The decomposition of an aqueous solution of a diazo-salt is, in most cases, a simple one, and belongs to the class of unimolecular processes for which me have the well-known expression 1 A - log = C (a constant). Measurements of the rate of decomposition of these compounds were first made by Hausser and Muller (Bull. Soc. Chim., 1892, {iii], 7, 721 ; 1893,9,353 ; also Compt. rend., 1892, 114, 549, 669,760,1438), 1 A t A - x who determined the value of - log - for the diazo-salts from Aniline (sulphate and hydrochloride). 0-, m-, and p-Toluidine (sulphate), 0-, m-, and p-Aminobenzoic acid (sulphate), m- and p-Sulphanilic acid, a t a temperature of from 40' to 64'.The results obtained showed that only the diazo-salts from p-sulph- anilic acid and p-toluidinesulphonic acid gave a constant value for p-Toluidine-2-sulphonic acid, 1 A - log -, all the others giving gradually diminishing values. t A - x Hausser and Muller explain this unexpected result, in the case of diazobenzene only, by adducing experiments in evidence of a specific retarding action " of the phenol formed during the decomposition. Hantzsch (Ber., 1900, 33, 2517) measured the rate of decomposition Aniline, p-Anisidine, p-Toluidine, $-Cumidine, p-Bromoaniline, and showed %hat at 25' all these substances gave a constant value for of the diazo-salts from the hydrochlorides of 1 A t 4-32 - log -.Hantzsch suggests that the non-agreement of his results with those of Hausser and Muller may be due to the existence of secondary re- actions set up at the high temperature of the experiments (40' to 64'). We have therefore measured the rate of decomposition of diazo- benzene chloride at temperatures frqm 20' to 60' in order to deter- mine, if possible, the temperature at which such secondary reactions might set in, this point being shown by the diminishing values for C. We shall show that, under- the conditions of our experiments, the1414 CAIN AND NICOLL: THE RATE OF figures for diazobenzene chloride give a constant value for the above expression at all temperatures between 20° and 60°.Similar results were obtained with the diazotoluene chlorides. The full list of amines and diamines, from which we have prepared and examined the corresponding diazo-salts, is as Eollows : Aniline, Benzidine. 0-, m-, and p-Toluidine. 0-, m-, and p-Nitraniline. Dianisidine. oo-Dichloro benzidine, psulphanilic acid. Tolidine. p-Aminoacetanilide. Most of the experiments of Hausser and Muller, and all those of Hantzsch, were made with solutions obtained by dissolving the pure, dry diazo-salt in water. The former chemists prepared the diazo-solu- tions from 0- and m-toluidine sulphate by adding a solution of sodium nitrite to an acid solution of the amine ; they state, specially, that addition of sodium sulphate to a solution of dry diazo-p-toluene sulph- ate in pure water has no effect on the rate of decomposition, and conclude that it is immaterial whether the solution is prepared one way or the other.Hantzsch (Zoc. cit.) states (and we have also found) that the presence of free mineral acid has no effect on the reaction. All our solutions have been prepared directly, as on the large scale; and as our results for diazobenzene chloride agree fairly well with those of Hantzsch, we feel justified in criticising those of Hausser and Muller from the point of view of our own. The method we used for determining the rate of decomposition was, in principle, the same as that used by the chemists to whom we have referred, namely, measurement of the volume of nitrogen evolved from time to time. The arrangement used for doing this was nearly the same as that of Hantzsch, who connected a flask containing the diazo- solution by means of a capillary tube with a nitrometer ; we have used a water-jacketed Hempel’s burette, and an ordinary purette also water-jacketed.In the determinations above 30°, we interposed a very small, spiral condenser, so as to avoid any error due to the in- complete cooling of the hot nitrogen. The question as to the measurement of time is the next considera- tion. It being, of course, impossible to bring the flask containing the diazo-solution to the required temperature instantaneously, it is necessary to fix on some point from which to reckon the time of reaction, so as to make the error as small as possible. Hausser and Muller, indeed, attempted to determine the theoretical starting point from the volume of gas evolved in successive periods of time after the right temperature was reached. By extrapolation, theyDECOMPOSITION OF DIAZO-COMPOUNDS.PART I, 1415 found the length of time which would have been required for the evolution of the gas produced during the heating of the solution. But there are certain objections to this method, for, in the first place, the “curve of the rate” (taking volumes as ordinates and times as abscissa) seems to have been produced backwards by freehand draw- ing, as by using Laplace’s interpolation formula we obtain a slightly different result, and, secondly, the first few numbers obtained in these experiments (as Hantzsch proves) are much too low, owing to some of the nitrogen (at first a large proportion) remaining dissolved in the solution, From a large number of preliminary observations, we believe that the method of Kantzsch, which we have adopted for reckoning the starting point, gives us a point which can only differ from the theo- retical point by a very few seconds.The flask then, having been nearly filled with the diazo-solution and connected by a two-holed caoutchouc stopper carrying a thermometer and a capillary tube with the measuring burette, was quickly heated to the temperature of the experiment by a Bunsen flame. The flask usually contained pieces of broken glass for purposes of adjustment and was well shaken during this operation to avoid overheating. The time was reckoned from this point, and the flask plunged into a water-bath which was kept a t the right temperature by a gas regulator. The gas evolved was now measured from time to time, and in many experiments the flask was heated to a higher temperature unti1,on cooling to the temperature of the bath, no increase in volume of the nitrogen was observed.This total volume of nitrogen determined experimen- tally always agreed well with the volume calculated from the amount of diazo-salt taken. The correction for the expansion of the liquid and the small volume of air in the flask was always- determined experimentally and sub- tracted from the readings of the burette. In the following tables, A is the total volume of nitrogen at the temperature and pressure of the experiment calculated from the weight of diazo-salt contained in the solution ; x is the corrected volume of nitrogen at the same temperature and pressure evolved during the time t (in minutes), C is the constant calculated according to the equation 1 A c=-log - t A - X .1. Diaxobenxene Chloride. 9.3 Grams of aniline (1/10 mol.) dissolved in 30 C.C. of hydrochloric acid of sp. gr. 1.16 (3/10 mol.) cooled with ice and 6.9 grams of sodium nitrite added (100 C.C. of a solution containing 69 grams NaNO, per1416 CAIN AND NICOLL: THE RATE OF litre). therefore contained 10 grams of diazobenzene chloride in a litre. made in the above proportions was used for each experiment : The solution thus obtained was made up to 1400 c.c., and A fresh solution Thirty-five C.C. were taken in each experiment. Temperature 20". 1. A=60 C.C. (13", 750 mm.).t. 116 3 31 159 180 192 355 393 422 43 9 458 481 1282 1329 1354 1424 X. 9.7 C.C. 11.1 ) ) 13% ), 15.3 ,, 16'2 ,, 26'3 ), 29'8 ,) 30-5 ), 31.5 ), 32-6 ,) 51.4 )) 33'7 )) 52.8 ), 53-9 ,) 54.5 ) ) C. 0 '000 6 6 0'00068 0'00070 0 -0 00 70 0 -000 7 1 0'000 7 0 0.00076 0 -00073 0.00073 0-00074 0*00074 0'00066 0'00069 0*00073 0.00073 Range 16 to 91%. Mean 0.00071 2. A=61 C.C. (14") 741 mm.). t. 45 1 474 486 506 532 545 578 596 607 1382 X. 31'4 C.C. 32.6 ), 33'2 ), 34'4 ) ) 36.4 ,) 37'4 ,, 39.2 ,, 40-1 ), 40.5 ,) 55.3 )) C. 0'00069 0*00070 0 *00070 0-00071 0 '00 074 0*00075 0 '000 7 7 0.00078 0.00078 0.00074 Range 52 to 92%. Mean 0'000736 Mean of the two experiments, 0'00072, Taking the first experiment, it will be seen that no value for C is recorded until 116 minutes have elapsed.The numbers obtained before this time are much lower and gradually increase until they become constant. This apparent departure from the law is due to the fact that the solution must become saturated with nitrogen before the correct volume is measured in the burette. That this is the correct explanation was very clearly proved by Hantzscb, and we have therefore left out these irregular figures from our tables. That there are considerable sources of error both a t the beginning and towards the end of the reaction is obvious, and we shall therefore usually note the range of the reaction through which our observations extended (thus, for example, " range = 20 to 60 per cent." means that our numbers extend from the point at which 20 per cent. of the diazo-salt has been decomposed until 60 per cent.hae been decomposed). The rangeDECOMPOSITION OF DIAZO-COMPOUNDS. PART I. 1417 E:f:ze oft. of our observations is usually considerably wider than that of Hausser and Muller or Hantzsch. The above numbers agree fairly well with those obtained by Hantzsch at a temperature of 2 5 O , whose results for C varied in four experiments from Om0O064 to 0.00072, the range covered by three experiments being 12 to 62 per cent. (The fourth experiment was made according to an admittedly more inexact titration method.) There is not much difference in the constants at these temperatures, but, as will be seen, the constants increase enormously at higher tem- peratures. C. Extreme values of 2. Lowest. Highest. -____ Series. 0.00278 0.00278 I.A=60*45 C.C. (16", 756 mm.) 11. A=59*8 C.C. (lS", 761 mm.) 0-00305 0'00305 I. A=59*7 C.C. (IS", 765 mm.) It. A=59'7 C.C. (13'5", 7565 mm. 45 to 382 53 to 314 16 12 12 8 15.4 C.C. to 56.1 C.C. (range 25 to 92 %) 17.2 C.C. to 53.0 C.C. (range 30 to 90 %) 25 to 75 81.5 to T8-5 Temperature 30". * 2 3 5 C.C. to 46'5 C.C. (range 40 to 78 %) 27.8 C.C. to 47.2 C.C. (range 46 t o 80 %) 0 *00864 0 -00902 Mean.. Mean. 0.002947 0 -002956 0.00295 0*00876 0-00879 0.00877 * The figures obtained in this and the following experiments are of the same character as those in the experiments a t 20". We have therefore arranged our results in an abbreviated form, giving, however, one set of figures in full for each substance. We made our next experiments at a temperature of 50°, the same as that at which Hausser and Muller worked.We have already mentioned that our experiments were not made under the same conditions as those of the above chemists, but apart from this there is much that is open to criticism in the figures which Hausser and Muller give, A serious error occurs in the numbers for diazobenzene chloride (Bull. Xoc. Chim., 1892, [iii]] 7, 721) which we quote here. We have added a new column showing the values for C, which we obtain on calculating out Hausser and Muller's results. VOL. LXXXI, 5 c1418 CAIN AND NICOLL: THE RATE OF Experiment 1.-Solution contained 6-25 grams of diazobenzene chloride per litre. A = 660 C.C. t. 16-5 26 -5 36.5 46.5 56.5 x. I C. (Hausser and Muller) Recalculated, C. and N. ~~~ 0.0303 0'0285 0,0262 0.0232 0'0205 Range 31 to 66 per cent, 0.0099 0'0099 0 -0087 0-0074 0'0063 Zxperiment 2. -Solution contained 9.47 grams of diaxobenzene chloride per litre (the solution used in our experiments contained 10 grams per litre).A = 453 C.C. 12.6 17.6 22'6 27'6 32'6 42'6 0. 206 C.Ch 255 $ 9 285 9 , 305 9 9 317.5 ,, 332.5 ,, C. Hausser and Muller) 0'0360 0'0348 0'0332 0.0317 0'0299 0'0267 Range 45 to 73 per cent. C. Recalculated, C. and N. 0.0209 0.0204 0'0190 0.0176 0*0160 0.0135 There is thus a very great discrepancy which we are quite unable to account for. We were led to check these results after drawing a curve showing the course of the decomposition. It was obvious that the curve could not represent the reaction. We may add that we have recalculated all the numbers given in the various experiments by Hausser and Muller and find them to be correct.Turning now to the figures given in the same paper for diazo- benzene sulphate, we find that four experiments were made with three different solutions, containing respectively 3'38, 6.7, and 10.8 grams of diazo-salt per litre. The corresponding values for C did not differ very much from each other ; hence Hsusser and Muller conclude that the decomposition is not influenced by the concentration, The numbers for C, however, in each experiment are not constant, they gradually diminish as the decomposition goes on j thus inDECOMPO!UTION OF DIAZO-COMPOONDS, PART I. 14 1 9 Exp. I they diminish from 0.0298 to 0*0210. Range 49 to 80 per cent. 9 , 2 9 , ,, 0.0289 ,, 0.0177.), 44 ), 82 ,? 9 ) 3 9 , ), 0.0325 ,, 0.0191. ,, 45 ,, 84 ,, 31 4 ) J ,, 0.0334 ,, 0.0206. ,, 50 ,, 86 ,) From these numbers, Hausser and Muller conclude that the phenol formed in the reaction has a specific retarding action, and to prove this made a fifth experiment, to which phenol was added. From the result of this, they claim to have shown that their ex- planation was a true one, but on comparing the figures obtained, me do not think the conclusion is justified. The solution contained 22.5 grams of diazo-salt per litre, with 10.5 grams of phenol per litre, and the values for C diminished from 0.0259 to 0.0216 (range 48 to 89 per cent . ) . We have compared the values of C in the above experiments at points representing equal amounts of decomposition. Thus, when 56 per cent.had decomposed, the value of C in two experiments mas 0-0284 and 0,0318, and in the phenol experiment 0.0259. When 66 per cent. had decomposed, we find C=O*O267, 0.0297, and in the phenol experiment 0.0255, Here the value for C in the phenol experiment is less than that in the two ordinary experiments, although these differ from each other more than one of them differs from the phenol experiment. But a t a, later stage we find : A t 75 per cent. decomposition the value of C was 0-0230 and 0,0221, and in the phenol experiment 0.0248. At 80 per cent. decomposition the value of C was 0*0210 and 0,0222, and in the phenol experiment 0*0242. Here the value for C in the phenol experimeut is greater than that in the other experiments. Experiments were made (Hausser and Muller, Zoc.cit.) adding, in- stead of phenol, phenylsulphuric acid, sugar, and oxalic acid, and from equally unconvincing data the authors conclude that substances con- taining the benzene nucleus retard the reaction, whilst those belonging t o the fatty series have no action. We think, however, that the results of Hausser and Muller do not lead to this conclusion, and in order to test this point further we have made experiments also at 5.0' t o see if, under the conditions of work- ing, the addition of phenol has any effect on the reaction. We think our numbers prove conclusively that there is no trace of either a retarding or accelerating action produced by this substance.1420 CAIN AND NICOLL: THE RATE OF Temperature 5 09 The solution contained 10 grams of diazobenzene chloride per litre as before.In Experiment 3 (p. 1421), the solution contained 4-57 grams of phenol per litre, this being the same proportion of phenol to diazo-salt as that in the experiments of Hausser and Muller : -~ t, -_____ 5.5 6 6 -5 7 7.5 8 9 10 12 13 15% 17 19 21 23 26 30 1. A=58*3 (7') 753 mm.). IL'. 17.7 C.C. 19.3 ), 20.85 ,) 22.55 ,, 24 Y , 25'4 ,, 27-8 ,, 29 9 3 , 33% ), 35.4 ), 39.1 ,) 41.0 ,, 43.1 ,, 45.0 ), 46.5 ,) 48-4 ) ) 50.25 ,) Range 30 to 84 %. C. 0.0286 0'0291 0.0295 0.0303 0.0307 0'0311 0.0313 0'0312 0.0311 0'0312 0.0311 0*0310 0'0307 0'0306 0'0301 0.0296 0.0287 Mean 0.0303 t. 9 9.5 10 11 12 13 14 16 18 20 22 24 26 2. A=58*3 ( 7 O , 753 mm.). X. 26.0 C.C. 27.3 ), 28.5 ) ) 30% ,, 32.6 ,) 36.0 ,, 38.85 ,, 41.3 ,, 43.25 ,, 45.0 ,) 46'45 )) 34.4 ,, 47.7 ) ) C.0*0285 0.0289 0.0291 0'0294 0.0296 0'0298 0.0298 0.0296 0-0297 0.0294 0 '0292 0.0288 0.0285 Range 44 to 80 %. Mean 0.0293 Mean of experiments 1 and 2, 0'0298. These figures show very clearly that the addition of phenol to the diazo-solution has absolutely no influence on the course of the re- action. A fourth experiment was made a t this temperature with a solution of different concentration, namely, containing 5 grams of diazo-salt per litre :DECOMPOSITION OF DIAZO-COMPOUNDS, PART I. 1421 i-I t. 8 9 10 12 13 16 17 18 20 22 24 27 30 16.4 C.C. to 45-4 C.C. (range 28 t o 77 %) 17.4 C.C. to 44'8 C.C. (range 30 to 76 %. X. 24.3 C.C. 27.1 ), 29.5 ,) 33'6 ), 40'6 ,, 41.9 ), 43.0 ), 45'3 ,, 47'1 ,, 48.5 ), 50-3 ,) 51.8 ,, 35'4 ,, 0.102 0'1181 0.102 0.111 Mean ...Range 40 t o 86 %. I. A=58*7 C.C. (7", 748 mm.) 11. A=58*7 C.C. (8" 750mm.) 0-028i 0.0289 04293 0.0296 0'0297 0.0305 0,0305 0 -0303 0-0304 0.0302 0'0298 0'0291 0'0286 9 10 11 13 15 17 21 24 28 15.1 C.C. 17.2 ,, 18'9 ), 20'3 ,, 22.6 ,) 23'8 ,) 25'1 ,, Mean 0.0296 Range 50 to 83 %. C. 0.02'15 0.0283 0.0286 0'0287 0.0287 0'0283 0'0278 Mean 0.0283 The very slightly less value of C in experiment 4 is sufficiently accounted for by the greater proportion of nitrogen which can be retained in the more dilute solution : thus, as Hausser and Muller and Hantzsch have shown, the concentration has no influence on the course of the reaction : Temperature 60". Extreme valueg of t. 1; to 69 1.5 to 6 r C. Extreme values 0.11 03 0-1078 ~ 0.1090 An examination of the values for C at the various tempera- tures shows that they increase enormously as the temperature is raised.This is seen very clearly in the curve where the following values for C are ordinates and the temperatures are abscissze :1422 CAIN AND NICOLL: THE RATE OF 166 147 188 199 222 Temperature. 20° 30 40 50 60 26.4 0'00178 0'00184 0*00189 29.4 32.6 33 9 0'00190 36 2 0'00189 CURVE No. 1. 26'3 29'3 32'4 33.8 36.3 C. 0-00072 0.00295 0*00877 0-0298 0.109 0.001 77 0-00183 0-00187 0'00189 0-00191 2. Diaxo-o-toluene Chloride. 10.7 Grams of o-toluidine (1/10 mol.) dissolved in 30 C.C. of hydro- chloric acid of sp. gr. 1.16 (3/10 rnol.), cooled with ice and 6.9 grams of sodium nitrite added (100 U.C. of the normal solution).The solu- tion of diazo-o-toluene chloride was made up to 1400 C.C. and therefore contained 11 grams of diazo-salt per litre, Thirty-five C.C. mere taken in each experiment, Temperature 20'. ~ ~~ 1. /I 2. Az58.3 (8*5", 758 mm.). 11 A358.3 (8V, 758 mm.). I I i I t. 147 166 188 199 222 2. 1 c.DECOMPOSITION OF DIAZO-COMPOUNDS. PART I. 1423 t. 236 299 388 430 474 X. 37.; 42.7 47 '5 49.2 50 '4 Range 45 to 85 X. 24 to 74 27 to 60 Temperature 20" (continued). 19-2 C.C. to 41.9 C.C. 0.0069 (range 31 to 70 %) 21'1 C.C. to 37.7 C.C. 0-0068t (range 35 to 62 %) C. 13 to 30 29.2 C.C. to 46.8 C.C. (range 50 to SO %) 10 to 24 23.8 C.C. to 42.5 C.C. (range 40 to 70 %) 0~00190 0.001 91 0*00188 0.00187 0 *00183 0'0229 0,0225 236 286 295 384 433 455 1.5 to 6.5 1'5 to 7 37.7 41 *9 42'6 47-3 49.2 49'8 16.6 C.C.to 44.7 C.C. (range 28 to 75 %) 16-7 C.C. to 46'3 C.C. (range 28 to 79 %) Mean 0.00187 11 Range 45 to 85 %. 0 *oo 19 1 0*00193 0'00193 0 '00 189 0.00186 0'00184 Jlean 0'00187 Seiies. I. A =60'6 C.C. (8*5", 730 mm.) 11. A=60*6 C.C. (8'5", 730 mm.) J. A=58'8 C.C. (8", 750 mm.) 11. A=58'8 C.C. (8", 750 mm.) 1. A =58*8 C.C. (SO, 750 mm.) 11. A=58'8 C.C. (8", 750 min.) Mean of the two experiments, 0.00187, Lowest of t. -4 I- 0.0954 0.0961 C. Highesl 0.0073 0-00713 Mean I . 0'0247 0,0244 Mean.. 0'103 0.113 Mean.. Mean. Om0O708 0*00704 0.00706 0.0240 0.0236 0.0238 0.0997 0.1057 0.1027 -1424 CAIN AND NICOLL: THE RATE OF The collected values for C are therefore : Temperature. 20° 30 40 50 C. OgO018'7 0*00706 0.0238 0.1 027 graphically represented by the following curve : CURVE No.2. Our results again differ from those of Hausser and Muller, who measured the rate of decomposition of diazo-0-toluene sulphate (Bull. Xoc. Chim., 1893, [iii], 9,353). The diazo-salt was prepared in exactly the same way as was ours, except that we used,hydrochloric instead of rrulphuric acid. The concentration of our solution was very near that employed in Hausser and Muller's first experiment, their second solution being tsvice as strong. Their experiments were made at 40° and the results were : 1, value for C gradually diminished from 0.026 to 0.020 ; 2, value for C gradually diminished from 0.0251 to 0.020. As is seen above, we obtain a constant value for C = 0.0238. Hausser and Muller do not offer any explanation of their results, 3. Bhxo-m-toluene Cht?oride.The diazo-salt was prepared from m-toluidine exactly as in the case of o-toluidine.DECOMPOSITION OF DIAZO-COMPOUNDS, PART I. 1425 Temperature 20". I. A=60*8 C.C. (12'5", 740 mm.) 11. A=60'9 C.C. (12'5", 739 mm.) I. A=60*2 C.C. (12", 746 mm.) 11. A=6O'O C.C. (12", 747 mm.) ~ ~~ ~ ~~ 1. ~ A=60'9 (12*5", 739 mm.). 11 11 8 8 t. 135 143 160 176 192 206 226 282 313 324 347 22.6 C.C. to 44.7 C.C. (range 37 to 74 %) (range 40 to 72 %) 23'4 C.C. tQ 43.6 C.C. 2. 0'0245 0.0253 28 '3 29 -7 32.5 34-7 37'1 38'7 40.8 45'2 47.2 48.0 49 *1 Range 47 to 81 %. C. 0*00201 0.00203 0-00207 0 000208 0'00213 0.00213 0.00213 0*00209 0'00207 0'00208 0*00205 Mean 0-00208 2. A=60'9 (12.5", 739 mm.). t. 97 109 122 135 143 160 176 206 226 243 282 324 350 X.22'4 24-8 27 '0 29 '0 30-2 33 '1 35 3 38'6 40-5 42'1 45 '1 47 '9 49 -7 Range 37 to 82 %. Extreme values of t. 40 to 122 38 to 113 84 to 24 84 to 22 C. 0*00205 0 -00208 0~00208 0'00208 0'00208 0 -0 0213 0'00214 0'00212 0~00210 0'00210 0'00208 0'00207 0~00210 llean 0'00209 Mean of the two experiments, 0*002085. Extreme values of x. Temperature 30". 28.6 C.C. to 52.2 C.C. (range 47 to 86 %) 26'9 C.C. t o 50.7 C.C. (range 44 to 84 2) Tempsrature 40". Lowest. 0.0069 0.00665 C. Highest 0*00712 0 '00720 Mean. 0.0256 0.0268 Mean.. - Mean. 0 '00702 0.0069 0-00696 0.0252 0.0262 0'0257 -1426 CAIN AND NICOLL: THE RATE OF d - 0 2 Series. !4 2 - .;: We have for the values of C, Temperature. zoo 30 40 C. E::f:r Extreme values of 2. Lowest. Highest.Mean. oft. -- ' I 1- C. 0*002085 0.00696 0.0257 A=58*9 C.C. (8", 749 ma.) graphically represented by the following curve : 9 300 to 4310 7.8 C.C. to 54.6 C.C. (range 13 to 92 %) CURVE No. 3. Hausser and Muller's results (Zoc. cit.), for diazo-rn-toluene sulphate prepared in solution (that is, as above) diminished from 0-0305 to 0.0219 at 40°. The concentration in this experiment was the same as ours. Two other experiments with solutions of different concentration gave different., although still diminishing, values for C. 4. Diazo-p-toluene Chloride. The diazo-salt was prepared from p-toluidine exactly as in the case of o-toluidine. Tempratwe 30'.DECOMPOSITION OF DIAZO-COMPOUNDS. PART I. 1427 Temperature 40'. 66 to 208 24-5 C.C. to 48.3 C.C. (range 41 t o 81 %) 80 to 144 28'2 C.C.to 41.2 C.C. (range 47 to 70 %) 80 to 181 28.2 C.C. to 45.7 C.C. (range 47 to 78 %) 0-0035 0.0035 0.0035 20 to 46 20 to 62 24-5 C.C. to 42'4 C.C. 1 (range 41 to 71 %) 24.7 C.C. to 48.8 C.C. (range 41 to 81 %) 27'3 C.C. to 46.8 C.C. (range 46 to 78 %) 20'2 C.C. to 49'3 C.C. (range 34 to 82 %) 0.0445 0.0450 2. A=59*1 (8*5", 748 mm.). 1. 8-59.1 (85", 748 mm.). -- 0. t. C. C. t. 2. 180 200 230 260 301 372 057 491 580 634 19.7 21.6 24.1 265 29.6 33.9 38.8 40 *7 43 *3 45*0 0.000978 0'000988 0'000989 0 -000994 0*00100 0-000995 0-001011 0'001032 0*000988 0'000981 210 230 260 301 368 454 491 580 630 22'3 23 -9 26'4 29 *4 34.0 39 -0 40'7 43.5 45e4 0'000980 0 *00097 9 0*000989 0'000993 0*001011 0 '001032 Om0O1032 0.000997 0'001007 Range 33 to 75 %.Mean 0'000995 Range 37 to 76 2. Hean 0*001002 Mean of the two experiments, 0 *000999. - d u o 0 p d $ 4 2 % - 9 6 5 8 9 8 11 - L I C. Series. Highest 0.00368 0*00360 0'00358 Mean.. 0*0119 0-0128 Mean.., 0.0463 0'0479 Mean ... Mean. 0*00361 0 -003 56 0 -00356 0.00358 0*0118 0'0122 I I- I. A=59*1 C.C. (a", 747 mni.) 11. A=59*1 C.C. (So, 747 mm.) 111. A=59*1 C.C. (SO, 747 mm.) I. A=59*5 C.C. ( S O , 742 mm.) 11. A=59*6 C.C. (So, 740 mm.) 0.0115 0*0116 0'0120 0.0455 0,0467 0'0461 - I. A=595 C.C. (8.5", 743 mm.) 11. A=59*5 C.C. (8'5", 743 mm.) 6 to 15 4 to 171428 CAIN AND NICOLL: THE RATE OF Collecting all the results for diazo-p-toluene chloride, we have : Temperature. 30° 40 50 60 70 or graphically the following curve : CURVE NO. 4. C. 0*000209 0*0009 9 9 0*00358 0-0120 0.046 1 Hantzsch obtained the value 0.000081 at 25O, and Hausser and Muller numbers diminishing from 0-024 to 0*018 for the sulphate at 64O.The above experiments on diazobenzene and the diazotoluenes ex- tend over a wide range of temperature, and show that at all these temperatures the rate of decomposition is in accordance with the law, thus confirming Hantzsch’s results at a low temperature and being opposed to those of Hausser and Muller at higher temperatures. Of the substances still to be described, only one (diazo-p-sulphanilic acid) was examined by IIausser and Muller, who found a constant value for C. We have therefore only measured the rates of decomposition of the following diazo-salts at one or two temperatures.DECOMPOSITION OF DIAZO-COMPOUNDS.PART I. 1429 ~ j t. 5. Diazo-p-sulpianilic Acid. 17.3 Grams of sulphanilic acid were dissolved in water and caustic sod:i. Forty C.C. of hydrochloric acid of sp. gr. 1.16 (4/10 mol.) were added and then 6.9 grams of sodium nitrite in solution. The solution of diazo-salt was made up to 1400 C.C. and then contained 15.7 grams of diazo-salt per litre. Thirty-five C.C. mere taken in each experiment. ~ l1 15 20 32 35 43 51 76 90 Temperature 60". 25 30 35 45 51 59 66 76 90 t. 1 2. 1 18'1 21-3 23'9 28 -3 31.6 33 '4 35.7 38'9 42 -9 Series. C. o(1 3; Extreme d g! values Pi ?G! o f t , +? 0*00640 0'00652 0'00648 0 *00635 0 -00658 0 .ooe19 0 -0061 6 0 -0 0 6 21 0.00633 16'4 C.C. to 44.7 C . C . (range 28 to 75 %) 20'2 C . C . to 42.9 C . C . (range 34 to 72 %) 0.0681 0.0711 0.0696 0.0712 0.0744 0.0723 Mean ...0.070S I. A=58.7 C.C. (go, 752 mm.) 11. A=58-7 C.C. (go, 752 mm.) c. 2* I 9 2 to 9 8 2.5 t o 8 8-6 11.8 15.5 22-3 23 *7 27.1 29 *9 38'2 42'5 0'00625 0'00649 0-006E5 0.00648 0'00641 0-00625 0'00606 0.00601 0.00621 Range 30 to 72 %. Mean 0'00636 11 Range 15 to 72 %. Mean 0.00631 Mean of the two experiments, 0.00633. Temperature 80". G. Extreme values of x. We have drawn a curve through the two points given by the above determination, and it is interesting to observe that from this curve the value for C a t 64O, the temperature a t which Hausser and Muller1430 CAIN AND NfCOLL: TEE RATE Ol made their experiments on this substance, corresponds almost exactly with the value they found, namely, 0.0106, as the mean of four experiments.CURVE No. 5. We are here, for the only time, in agreement with Hausser and Muller’s results, and it is important to note that their experiments were made (I) with the solid diazo-compound, (2) in three different concentrations. 6. Diazo-o-nitro6enzene Chiwide. 3*45 Grams of o-nitraniline (1/40 mol.) were dissolved in 11 C.C. of hydrochloric acid of sp. gr. 1-16 (4.5140 mol.) and diazotised by the addition of a solution of 1.73 grams of sodium nitrite. The diazo- solution was made up to 700 C.C. Seventy C.C. of this solution were taken in each experiment. This solution differs from the corresponding ones from aniline and the toluidines in being more dilute; instead of a diazo-solution con- taining 1/10 mol. in 1400 c.c., we have 1/20 mol. in the same volume, and, as is well known, it is necessary to use a fairly large excess of acid in order to diazotise the nitranilines successfully, so that we have here 44 mols.of acid to 1 mol. of base, We do not think that these changes are sufficiently great t o prevent us from comparing the con- stants for the diazo-salts from the nitranilines with those from the other amines examined. This diazo-salt is exceedingly stable : at 70°, only about 50 per cent. was decomposed after 174 hours, so that we have determined the rate of decomposition at looo,DECOMPOSITION Ol? DIAZO-COMPOUNDS. PART I. 1431 Temperature 100". 2. A=59'1 (8'5', 748 mm.). 1. A=59'1 (8*5", 748 mm.). C. t. 2. C. t. 5'5 10 17 25 35 45 55 65 79 115 135 z. 7 17 20 31 35 45 50 70 80 90 100 5 *1 11.6 13 '2 19.5 21 *5 26.1 28'3 35.5 38-6 41 '2 43-5 0 *00560 0.00553 0.00549 0.00561 0.00561 0*00.562 0.00566 0.00569 0.00515 0.00576 0.00578 4.0 7.1 11 '2 15.6 20.8 25.3 29.4 32-6 37 '4 45'7 48'9 0.00553 0-00556 0*00537 0.00532 0.00538 0.00539 0 -00543 0 '00536 0-00551 0 -005 60 0*00565 Range 9 to 73 %.Mean 0.00564 Range 7 to 82 %. Mean 0.00546 Mean of the two experiments, 0.00555. 7. Diaxo-rn-mitrobenxene Chloride. The diazo-salt was prepared from m-nitraniline exactly as in the case of o-nitraniline. Temperature 809 1, A= 59.9 (13", 753 mm.). 2. As59*9 (13', 763 mm.). t. C, C: t. (E. &. 74 81 99 148 164 181 212 230 254 277 9s 60 70 85 100 120 157 168 206 219 0*00303 0'00307 0.00306 0*00308 0 *003 12 0.00319 0*00328 0*00313 0'00319 24 '1 26 '1 29.1 ao ~6 39 -5 41.7 44.6 47.7 49 -5 50% 52 *6 0'00302 0.00307 0.00310 0.00314 0 *00316 0.00315 0.00326 0.00326 0'00330 0-00313 0*00330 20'5 234 26 9 30-4 34.6 41 '0 42'7 46.3 47.9 Range 40 to 88 %.Mean 0'00317 Range 34 t o 80 %. Mean 0'00312 Mean of the two experiments, 0*003145.1432 m 53 d 2 4 z 3 14 14 CAIN AND NICOLL: THE RATE OF Extreme values o f t . 4 to 25 2 to23 Temperature 1009 C. Highest. Extreme values of x. Series. Mean. 0'0322 0-0329 0.0325 Lowest I. A = 58'2 C.C. (So, 758 mm.) 11. A=58'2 C.C. (8", 758 mm.) 14.8 C.C. t o 49.6 c.c (range 25 to 83 %) 8.3 C.C. to 48'2 C.C. (range 14 to 81 %) 0.0315 0.0324 0.0332 0.0334 Mean ... 8. Diaxo-p-nitrobenzene Chloride. This diazo-salt was prepared from p-nitraniline exactly as in the case of o-nitraniline. Temnperatz~re 80".1. A=58'3 ( 8 V , 758 mm.). 2. A=58-3 (8*5', 758 mm.). -- t. C. C. t . X. 0. 22 25 28 32 36 41 46 53 66 76 a2 96 0'00784 0 -00748 0'00748 0*00756 0 -00750 0.00751 0*00730 0.00734 0.00714 0*00728 0.00737 0.00742 25 28 32 36 41 46 53 58 66 71 89 96 19.9 22 '0 24'6 26-9 29 '6 31'5 34.7 36'6 39.0 40'4 45 -1 46.5 0.00726 0-00735 0'00744 0.00747 0.00751 0.00731 0 -0074 1 0 '00740 0.00727 0.00722 0.00725 0-00723 18.1 20'4 22'3 24'9 27.0 29.6 31.4 34.5 38 -6 42 -0 43'8 47.0 Range 31 to 80 %. Mean 0.00739 Range 34 t o 80 %. Mean 0'00734 Mean of the two experiments, 0-00736. The foregoing figures show that, in each case, the reaction is a unimolecular one, and before describing our experiments on the remaining substances, namely, aminoacetanilide and the diamines of the benzene series, we shall now discuss the results up to this point, as the decomposition of the diazo-salts of the latter substances is not quite so simple.I n most of the above series of experiments, the valueDECOMPOSITION OF DIAZO-COMPOUNDS. PART I. 1433 of C seems to rise to a maximum at about the point of 50 per cent. decomposition. This is no doubt due t o the slight increase of tem- perature in the flask (sometimes 0.5' to 1") produced by the heat evolved in the reaction. Before proceeding t o compare these constants more closely, we must here .remark that the solutions of the diazo-salts from aniline, the toluidines, and sulphanilic acid mere all equivalent, that is, contained the same number of molecules. The amount of free hydrochloric acid was the same, but there was an extra mol.of sodium chloride present in the diazo-solution of sulphanilic acid, as we started from the sodium salt. I n the case of the diazo-salts from the nitranilines, although their diazo-solutions were all exactly equivalent among themselves, yet it wag necessary to use a larger amount of hydrochloric acid, and it was found more convenient to make up the solutions to half the concentra- tion of the previous ones. We think that we are quite justified in comparing the constants of the diazonitrobenzene salts with those of the other substances, as Hantzsch has shown very clearly (Zoc. cit.) that difference in concen- tration has no effect on the rate of the reaction in the substances which he examined, and this is, of course, applicable to all unimolecular reactions.Hantzsch has also shown that the presence of hydrochloric acid has no influence on the rate of decomposition. Comparing first of all the values for C for the three diazotoluene chlorides and diazobenzene chloride, we find that the introduction of the methyl group in the ortho- or meta-position in the latter makes the compound less stable, but in the para-position renders i t much more stable. Of the diazo-o- and diazo-m-toluene chlorides, the m-compound is the less stable. This conclusion is the same as that at whkh Hausser and Muller arrived (Bull. Xoc. Chirn., 1893, [iii], 9, 353). The introduction of the acid groups SO,H and NO, has the effect of enormously increasing the stability. Diazosulphanilic acid is much more stable than diazo-p-toluene chloride, and all three diazonitro- benzene chlorides are much more stable than diazosulphanilic acid.I n the case of the diazoriitrobenzene salts, the most stable is the ortho-, then comes the meta-, and lastly, the para-cornpound. The influence of the position of the nitro-group on the stability of the diazo-compound is thus quite different from that of the methyl group. We have collected the values for C in the following table and curve (p. 1434) : VOL, LXXXL Z D1434 - Temp- erature. 20" 30 40 50 60 70 80 90 100 Aniline. 100 90 80 70 60 50 40 < 30 20 10 0 Toluidine. Sulph- anilic Ortho. 1 Meta. I Para. 1 acid* CAIN AND NICOLL: THE RATE OF Ortho. Meta. -1:- - - 1 - l - - - I - Diazo-salts from Para. - - - - 0'000999 0'00358 0.012 0 *00072 0 '00295 0.00877 0'0298 0*109 - - - - 0'00633 0*00187 0 -00 706 0'0238 0.1027 - - - 0.00208 1 0 '00696" 0.0257 - - - - * This figure appears to be slightly too low.CURVE No. 6. 0.02 0.04 0.06 0'08 0'10 0'12 Before we can compare the stability of, for iniltance, diazo-p-nitro- benzene chloride with the diazochlorides from aniline and the tolu- idinee, it is necessary t o know whether the ratio of the constants at different temperatures is the same.DECOMPOSITION OF DIAZO-COMPOUNDS. PART I. 1435 S ~ l p h - By putting the value of C for diaaobenaene chloride at each tempera- ture equal to unity, and calculating the corresponding values of C for the three diazotoluene chlorides, we obtain the following : Nitraniline. Temperature. Ortho. Meta. 20" 30 40 50 60 Para.Diazobenzene I Diazo-o-toluene Diazo-m-toluene Diazo-p-toluene chloride. chloride. I I chloride. , chloride. 1 2.6 1 1 2-4 1 2.7 1 1 , 3.4 I I - I 2.9 2.36 * 2.9 - - 0 *07 0.11 0.12 0.11 * See note on previous page. We shall, therefore, not be far from the truth if we compare diazo- pnitrobenzene chloride (at 80') with diazosulphanilic acid (at SOo), diazosulphanilic acid (at 60') with diazobenzene chloride or diazo-p- toluene chloride (at 60°), and hence obtain a comparison between the stabilities of these diazo-sat ts. Carrying this out, and putting the value of C equal to unity for each substance successively, we obtain the following numbers, which show the relative rate of decomposition of each diazo-salt for any given temperature. (For comparing diazobenzene chloride and the diazo- toluene chlorides, the constants at 40' have been used.) Diazo-salts from .Aniline. - 1 8.7 16 '6 160 378 2195 Toluidine. 1 2 7 23'8 4 5 ' 1 435 1028 5962 1-08 2.9 25-7 48'7 470 1110 6436 - 1 1.9 18-3 43 -1 250 - 1 9-6 22-8 132 - 1 5.8 I 1 2 -36 13.7 The very great stability of diazo-o-nitrobenzene chloride is thus seen at a glance; i t is more than 6000 times as stable as diazo-m-toluene chloride, the rate of decomposition of the latter being 6436 times greater than that of the former. We may here remark that Hantzsch 5 ~ 21436 CAIN AND NICOLL: THE RATE 0% 0*00301 1 ' 35 56 69 95 19'4 0.00184 94 2o I 1;:; I 0.00231 392 0-00064 334 1238 i ~ 0.00034 1119 found diazo-p-toluene chloride to be about 8 times more stable than diazobenzene chloride ; this agrees with our result (8.7).By using this table and the table of constantg, it is easy to find what percentage of any of the above diazo-salts would be decomposed in a given time. For instance, if a' solution of diazo-p-nitrobenzene chloride is prepared and kept at 20' for 1 week, the amount of decom- position may be calculated as follows. The constant a t 20' would be the constant for diazobenzene chloride (0*00072) divided by 160 = 0.0000045 ; t = 1 week = 10080 minutes, so we have : 10.5 1 0 00245 17'0 0.00215 19.3 0*00;84 25.5 1 0.00074 37 -1 0-00039 1 A . c = - log - t A - x ' log ____ loo whence 1 0*0000045 = - 10080 100-x' x = 9.9; thus, 9.9 per cent. of thediazo-solution a t 20' would be decomposed in one week. 9-Diaxo-p-cLcetclminobenzene ChZoride.Fifteen grams of p-amineacetanilide ( l / l O mol.) were dissolved in 30 C.C. of hydrochloric acid of sp. gr. 1.16 (3/10 mol.), the solution cooled, and 6.9 grams of sodium nitrite added. The solution thus obtained was made up to 1400 C.C. and contained 19-75 grams of diazo-salt per litre. We have measured the rate of decomposition of the diazoacetanilide at 80' and looo, and a t each temperature find that the value of C diminihes very rapidly. Temperature 80".DECOMPOSITION OF DIAZO-COMPOUNDS. PART I. 1437 Temperature 100". A=58'6 (SO, 751 mm.). - __ t. 2. ~ ~ 3 8.9 10 18.1 47 27-7 173 39.4 282 45-3 472 51 '6 ____.-____ C. 0 0238 0.016 0.0059 0'0028 0'0023 0 0019 The reaction is thus not a unimolecular one, being obviously com- plicated by the simultaneous decomposition of the diazo-salt and elimination of the acetyl group by the free mineral acid.By using acetic acid instead of hydrochloric acid, the hydrolysis does not take place, and the reaction proceeds in accordance with the law. The p-aminoacetanilide was diazotised as before, but 3/10 mol. of acetic acid was used in place of the mineral acid. Temperature SO". t. 3 4 6 10 12 14 17 20 23 28 33 36 40 48 60 84 X. 4'5 6-3 9'5 12% 14'2 16'3 18.5 21'3 24.3 27'3 31'6 35'2 36.8 38'8 42'2 46'3 C. 0'0110 0.0117 0'0121 0'0117 0'0114 0*0111 0*0111 0'0108 0'0109 0'0111 0.0112 0~0111 0'0110 00108 Oo0104 0'0101 Range 7 to 75 %. Mean 0*0111. t. 6 10 12 14 1 7 20 24 28 36 62 a ~ x. 8'6 11 *1 13'2 15'1 17-1 20'3 23'5 27 *5 31 -1 37 '4 48'5 0'0109 O'G108 0'0105 0'0102 0'0101 0'0102 0-0104 0*0107 0'0109 0-0113 0'0108 Range 1 4 t o 78 %.Mean 0-0106. Mean of the two experiments, 0'01085.1438 CAIN AND NICOLL: THE RATE OF 100 140 189 232 420 The diazoacetate is thus about 6.5 times more stable than diazo- sulphanilic acid. I n examining the tetrazo-salts prepared from the diamines, benz- idine, tolidine, dianisidine, and oo-dichlorobenzidine, we have ob- served singular differences in their behaviour. It is obvious that there might be a difference in the stability of the diazo-groups of any one substance, If this were the case, the re- action could not proceed unimolecularly, as an intermediate substance mould be formed containing a single diazo-group, which would then proceed to evolve nitrogen. The effect of this on the value of C (calculated as if the formula for a unimolecular reaction applied in this case) mould be either t o diminish or increase it.I n two cases, namely, the tetrazo-salts from benzidine and tolidine, the value of C gradually diminishes; in the case of the tetrazo-salt from dianisidine, the value increases, but in the case of the tetrazo- salt; from oo-dichlorobenzidine, the value is constant, showing that the two diazo-groups in this substance are decomposed a t the same rate. 22.1 0-00203 100 21 -9 0 *o 020 1 33.0 0.00187 189 33.2 0 -001 89 36'5 0.00179 232 37'0 0'00184 28.0 0~00200 140 1 27.8 0.00198 45.5 0.00151 420 1 45'4 0*00161 I 10. Tetraxodipr7lenyZ Chloride. 9.2 Grams of benzidine (1/20 mol.) were dissolved in 30 C.C. of hydrochloric acid of sp.gr. 1*16 (3/10 mol.), the solution cooled, di- azotised with 6.9 grams of sodium nitrite, and made up t o 1400 C.C. Thirty-five C.C. were taken for the experiments : Temperature 60'.DECOMPOSITION OF DIAZO-COMPOCNDS. PART I. 1439 Temperature 60". A=59*0 (lo", 754 mm.). 33 53 71 95 248 23.3 31 '2 35.7 40.2 50.5 0.0066 0.0062 0.0057 0 0052 0 '0034 The reaction is thus not a unimolecular one, as the vaIue of C is not constant. We are of opinion that the intermediate compound, diazoy -h ydrox ydi pheny 1 chloride, OH* C6H,*C, H, *B ,GI, is continually being formed and decomposed. 11. Tetraxoditolyl Chloride. The solution of this salt mas prepared as the preceding one, substi- tuting 10.6 grams of o-tolidine for the benzidine : Temperature 50".t. 36 57 79 104 144 309 I 23'6 30.9 36 '6 41 -2 45.1 52.3 0*0062 0-0057 0.0054 OmO051 0.0044 0.0031 36 57 79 104 343 385 X. 22 *5 30.6 36-5 40.5 43'8 51 '2 C. 0.0058 0 0056 0.0054 0 %04 9 0-0042 0.0023 Here, again, the reaction is not unimolecular, probably due to the formation and decomposition of the intermediate diazop-hydroxydi- tolyl chloride, OH*C,H,Me*C,H,~~e*N~*cl. 12. Tetruxo-oo-dichlorodiphenyl Chloride. The solution of this salt mas prepared as No. 10, substituting 12.6 grams of oo-dichlorobenzidine for the benzidine :1440 THE RATE OF DECOUPOYI'I'ION OF DLAZO-COMPOUNDS. Tenzperature 10 0" A=59-9 (9*5", 741 mm.). C. t. X. 9 20 46 109 161 185 202 3 *9 7.5 15.2 31'1 38.9 43'0 45.3 Range 6.5 to 75 %. Mean 0'00294. 0'0033 0.0029 0.0028 0.0029 0.0028 0'0080 0-0030 'l'he decomposition in this case follows the lam.* 1 3. Telraxo-oo-dirnetlhoxydiphenyl Chloride. The solution of this salt was prepared as No. 10, substituting 12.2 grams of dianisidine for the benzidine : Temperature 100". 1. A=59*2 (lo", 752 mm.). t. i x. 69 27 -7 80 38'4 87 1 35.2 119 45 -5 149 1 53'0 C. 0.0035 0.0037 0.0040 0'0043 0.0045 0'0053 OYjO65 2. A = 59.1 (lo", 753 mm.). t. 61 73 92 104 116 129 156 2. 22.6 28.0 35-6 39.8 43 '4 47 0 51.9 C. 0.0034 0.0038 0'0043 0.0047 0'0050 0.0053 0 -0058 This reaction also is not unimolecular. As the tetrazo-salt from dichlorobenzidine is the only salt which decomposes in accordance with the law, we can compare its constant only with those of the foregoing table. It is seen that its constant at 100' (0.00294) is less than that of o-nitroaniline (0-00555), so that it is 1.9 times more stable than the latter. * The product of decomposition is not the dihydroxy-compound, as in the caw of benzidine and tolidine. I am investigating this at present.-[J. C. C.]CAMPHORSULPHONIC ACID (REYCHLER). 1441 As regards the remaining substances which do not conform to the law, we can of course only very roughly compare them among them- selves. We may say that the stability of the tetrazo-salt from diztnisidine is of the same magnitude as that from dichlorobenaidine; then comes the tetrazo-salt from benzidine, about as stable as diazosulphanilic acid, and, lastly, the tetrazo-salt from tolidine is about five times as stable as diazobenzene chloride. We are at present engaged in studying the decomposition of diazo- salts of the naphthalene series. We wish to thank Messrs. Levinstein, Ltd., Manchester, for kindly supplying us with the pure aminoacetanilide and dichlorobenzidine used in this work. CHEMICAL LABORATORY, MUNICIPAL TECHNICAL SCHOOL, BURP, LANCASHIRE.

ISSN:0368-1645    

DOI:10.1039/CT9028101412

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

CAMPHORSULPHONIC ACID (REYCHLER). 1441 CXLI1.-Studies of the Terpenes and Allied Compounds. The Sulphonation of Cumphor. I. Camphor- sulphonic Acid (Reychler): the Formation of An- h ydramides. By HENRY E. ARMSTRONG and T. MARTIN LOWRY. ALTHOUGH in determining the structure of camphor to be that repre- sented by the formula chosen, with remarkable felicity, 6y Bredt, in 1893, chemists have decided an issue which had long engaged attention, the problems offered by camphor and allied compounds are still many and intricate. No substance known t o us suffers rearrangement of its parts and undergoes a complete change of type more readily than does camphor-for example, under the influence of dehydrating agents. Such changes appear the more remarkable when it is remembered that it is but a mono-ketone derived from a ‘ phane ’ or saturated cycloid hydro- carbon : indeed, no better illustration can be given than that which camphor affords of the extraordinary effect exercised by oxygen in promoting change. There can be little doubt that the ketonic group is the centre from which the primary influence proceeds in all cases.But great as is the advance in our knowledge, the ‘‘ mechanism ” of many of the changes involved in the passage from camphor to com- pounds of other types is still far from being understood, and we are1442 ARMSTRONQ AND rAowRty : SOLPHONATION OF without any clue as to the manner in which it is formed, and as to the part which camphor and compounds such as the terpenes play in nature : in this connection, the fact that camphor is so rarely met with whilst terpenes are of universal occurrence is in itself remarkable.The problems which the substitution derivatives of camphor offer are in some respects peculiar. Usually the hydrogen atoms of the CH, group contiguous with the CO group are first affected ; in fact., nearly all the known substitution derivatives are of this type. It is only on sulphonation that camphor behaves “ abnormally,” the sulphonic group entering one of the median methyl groups in the so-called Ir-position; and not only is the action abnormal in respect of the position occupied by the sulphonic group, but it also involves the ‘‘ optical inversion” of the camphor. It is therefore obvious that the sul- phonation either involves, or is attendant on, changes in the molecular structure of the camphor other than those which ordinarily accompany the process.On this account, the further study of the action of sul- phuric acid on camphor became desirable ; the discovery made by Reychler in 1898 (BUZZ. SOC. Chim., [iii], 19, 120) that camphor can be easily sulphonated in another manner, and without undergoing inversion, accentuated the importance of extending the inquiry. Reychler’s method consists in merely adding camphor (3 parts) to a mixture of acetic anhydride (4 parts) with ordinary concentrated sulphuric acid (2 parts) ; the sulphonic acid gradually crystallises out a t the ordinary temperature, the greater part separating within two or three days. The extreme ease with which the camphor is sulphonated is altogether remarkable, but the most noteworthy circumstance in connection with the acid is that whereas only a single series of salts and a single sulphochloride were obtained by Reychler, he described two distinct compounds formed by the action of ammonia on the sulpho- chloride-the one melting at 223’ and the other a t 132’.These he regarded as camphorsulphonamides of the formula C,oH,,O(SO,*NH,), and the analytical results which he quoted are in accordance with this conclusion. As determinations of molecular weight made by the boil- ing point method-with the object of ascertaining whether perhaps the two compounds were not polymerides-gave similar values ap- proximating to the formula C,oH,70,NS, we were content at first to accept Reychler’s view, especially as on substituting piperidine for ammonia we obtained two undoubtedly isomeric piperidides of normal composition’. It appeared to be not improbable, in fact, that the crude sulphonic acid was a mixture of stereoisomeridea, and that Reychler had succeeded in separating the isomerides only in the case of the amides (compare Lowry, Trans., 1898,’73, 569, 986).But we were obliged to abandon this explanation on finding that the properties of the sulpho- chloride were unaffected by recrystallising it repeatedly. Ultimately,CAMPHOR. I. CAMPHORSULPHONIC ACID (REPCHLER). 1443 observations were made which led to the discovery that either of the compounds could be obtained at will. It was found that by making use of a dilute solution of ammonia, only the compound of higher melting point-which is apparently the normal product -was formed ; whereas if a concentrated solution of ammonia were used and the interaction allowed t o proceed unchecked, the compound of lower melt- ing point was obtained, but in admixture with a greater or less propor- tion of the compound of higher melting point, Precisely similar results were obtained with the sulphobramide which we prepared from the acid.But no variation in the proportion in which the two piper- idides were produced was noticed on varying the conditiuns of inter- action ; and in conformity with Reycbler’s statement, we could obtain only a single anilide. As the compounds formed by the action of ammonia answered to the descriptions given by Reychler, i t did not seem necessary to analyse them.Bearing in mind the ease with which the sulphonation is effected, it was not unnatural to suppose that the camphor had undergone sul- phonation in the a-position, and that we were dealing with stereoiso- meric a- and a’-sulphonamides, the formation of which from a single acid could be accounted for on the assumption that the ketonic group took part in the interaction. This view received support from the observation made at an early stage of the inquiry that the supposed amide of lower melt- ing point was converted into that of higher melting point by merely warming it either with a mineral acid or with bromine-the very agents which are most frequently active in bringing about stereo- isomeric change. We therefore continued to accept Reychler’s con- clusion that the two compounds were isomeric, and referred to the compounds as stereoisomerides in our preliminary communication (Proc., 1901, 17, 182).On applying Reychler’s method to a-chloro- and a-bromo-camphor, i t was found that although these were sulphonated somewhat less readiIy than camphor, they gave rise to acids isomeric with those described by Kipping and Pope ; these were obviously derivatives of the Reychler acid, as they could be converted into derivatives of this acid by reduction. Each of the acids gave but a single sulphonamide. Whereas, however, the bromosulphonamide gave on reduction the labile camphorsulphon- amide (m. p. 132’), the chlorosulphonamide-which was much less readily reduced-gave the stable compound melting at 223’. On attempting to prepare the bromo-acid by the reversed method from camphorsulphonamide and bromine, two brominated compounds were obtained, the one melting at 166’, the other a t 186’.Neither OF these was identical with the amide prepared directly from bromo- camphorsulphonic acid, but as both, on reduction, gave the supposed ‘‘ camphorsulphonamide ” melting at 2234 they were obviously related1444 ARMSTRONG AND LOWRP: SULPHONATION OF to it in some simple way. Eventually they were found to be anhydr- ides formed by the withdrawal of the elements of a single molecule of water from the bromosulphonamide. The one melting at 186' was readily obtained from the a-bromocamphorsulphonamide by merely boiling this with acetic anhydride, whilst both were formed on digest- ing the amide with bromhydric acid.Bearing in mind the manner in which they are prepared and their behaviour on reduction, it is probable that the anhydride melting at 186' is directly derived from dibromo- camphorsulphonamide, whilst that melting at 166' is the stereoisomeric a'-bromo-compound. As the two compounds described by Reychler as camphorsulphon- amides were both found to be unaffected by acetic anhydride, our belief in the existence of two isomeric amides derived from the acid remained for some time undisturbed, especially as we had been able to prepare two undoubtedly isomeric piperidides. The formation from camphor- sulphonic acid of two isomeric SuIphonamides could not well be explained unless they were regarded as stereoisomeric a- and a'-compounds, but as the investigation proceeded, we were impressed by the difficulty of ob- taining direct proof that the Reychler acid was in reality an a-derivative of camphor, particularly after we had discovered that its sulphobromide was converted into P-bromocamphor and sulphur dioxide when decom- posed by heat.Eventually we were led to take the step of controlling the statements put forward by Reychler. It was then discovered that whilst the compound melting at 132' had the composition of camphor- sulphonamide, the supposed amide melting at 223O was not an isomeric substance but the anhydride of which we had previously obtained stereoisomeric bromo-derivatives ; and that although it could not be obtained by means of acetic anhydride, it was readily prepared by heating the sulphonamide above its molting point.Whilst i t affords proof that Reychler's acid is a single substance, the evidence thus far adduced throws no light on the nature of the acid, and is compatible with the view that it is an a-derivative: in other words, that sulphuric acid behaves, under certain conditions, in what may be said to be a normal manner towards camphor. The sulphonatiori is effected with remarkable readiness, almost more readily than bromination, and it might therefore be anticipated that the action would proceed in the same manner in the two cases. But as no trace of camphoric acid is formed on oxidising Reychler's acid with nitric acid, it is difficult to believe that the acid can be an a-derivative. It may be mentioned here, as an indication that the in- troduction of the S0,H group increases the stability of the molecule, that a-bromocamphorsulphonic acid is only very slowly oxidised when boiled with nitric acid-even in presence of silver nitrate.Passing to the positive evidence as to the nature of the acid, atCAMPHOR. I. CAMPHORSULPHONIC ACID (REYCHLER). l4+5 present we have but one fact, namely, that P-bromocamphor is readily obtained by decomposing its sulphobromide. Hitherto, it has always been found that the chloro- and bromo-compounds prepared by decom- posing sulpho-chlorides and -bromides contain the halogen in the posi- tion originally occupied by the sulphonic group, even in the cases in which the sulphonic acid is capable of undergoing isomeric change. There would be no reason to doubt this in the case of camphor were it not that the /I-bromo-derivatives have been prepared by a process of isomeric change from the a-derivatives, and it would therefore not be surprising if a similar transfer were to take place under thesomewhat drastic conditions involved in the formation of a simple bromo-deriva- tive by the decomposition of a sulphobromide.Evidence that the two a-positions are free in Reychler’s acid is afforded, however, by the fact that what appear to be isomorphous mixtures of chlorobromosulphonamides are obtained by the action of bromine on a-chlorocamphorsulphonamide, and of chlorine on the a-bromamide, whilst the a-bromo-compound appears to give only a single substance when brominated, and the a-chloro-compound but a single dichloro-derivative.But this evidence is of a much less striking character than that obtained in the case of the chlorobromocamphors (Lowry, Trans., 1898, 73, 569), and cannot be regarded as affording any conclusive proof of the position of the sulphonic group. A second argument to the same effect is afforded by the fact that P-bromocamphor cannot be sulphonated to any appreciable extent under conditions which determine the sulphonation of a-bromocamphor, which is especially remarkable when it is borne in mind how easily camphor is sulphonated and that a-bromocamphor is sulphonated with- out difficulty; there is no reason to suppose that a bromine atom in the P-position would exercise so complete a n inhibiting influence as to prevent all action if the a-position be that attacked on sulphonation.In further support of this argument, it may be pointed out that whilst a-bromocamphor is not attacked by hydroxylamine, a hydroxime is ob- tained without difficulty, not only from p-bromocamphor (Forster), but also from camphorsulphonic acid. Assuming the foregoing arguments to be sound, the only conclusion we can draw is that the Reychler acid is a /I-derivative of camphor, The anhydrosulphonamides,” to which reference has frequently been made, are compounds of considerable interest if the lesson which their formadion conveys b3 considered. I n ordinary cases, the sulphon- amide is formed directly from the sulphochIoride, and there is no extraneous group which can come into play, but in camphor the CO group must also be considered. If it be supposed that, instead oE the interaction taking place ‘‘ normally ’’ between ammonia and the S0,Cl group, the CO group is affected and unites with the ammonia,1446 ARMSTROKG AND LOWRY : SULPHONATION OF and that subsequently hydrogen chloride and water are eliminated, a closed chain would be formed in the following manner : *?*OH --f *?*OH + 4 .*SO,CI NH, *SO,*NH *SO,*N The tendency of the ammonia to combine with the ketonic group would be less, it may be supposed, the higher the temperature, and the S0,Cl group would therefore exercise the superior attraotion at higher temperatures. I n point of fact, the amide is only formed from camphorsulpho-chloride and -bromide when the action is allowed to proceed uncontrolled ; the more carefully the operation is conducted, the greater is the amount of anhydro-compound formed ; and this may easily be made the sole product, but the amide is never obtainedalane.This argument finds further support in the fact that the bromo- and chloro-sulphochlorides yield only the amide. It may be supposed that the introduction of the halogen leads to a considerable reduction of the attractive power of the ketonic group ; and it may be noted incident- ally that the non-formation of a hydroxime from a-bromocamphor affords direct evidence that the a-halogen atom does exercise such an inhibiting influence. An explanation of the action of acids, which are far more active as ‘I dehydrating agents ” than even acetic anhydride, is easily given on the assumption that the first product is an additive compound, thus : I n a similar manner, when acetic anhydride is used as dehydrating agent, the action may be supposed to involve the formation of an intermediate additive compound of the acetal type.It remains only to refer to the two camphorsulphopiperidides. It does not seem probable that these are stereoisomerides, as all attempts to convert them into one another by the action of mineral acids have been unsuccessful. I t appears to us that their formation is most satis- factorily explained by assuming that a series of changes takes place similar to that involved in the formation of the anhydramides. The piperidide melting at 140°, which can also be prepared by reducing a-bromocamphorsulphopiperidide, is probably a piperidide of the normal type, C,,H,,O*SO,*NC,H,,, formed in the normal manner.The forma- tion of an isomeride may be accounted for on the assumption that an additive compound of ths aldehyde-ammonia type is formed, which is converted into a sulpholactone by the subsequent elimination of hydrogen chloride ; thus :CAMPHOR. I. CAMPHORSULPHONIC ACID (REYCHLER). 1447 A t present, however, no proof of the correctness of such an explan- ation can be given. CamphorsuZphonic Acid (Reychler). In preparing the acid, either ordinary concentrated sulphuric acid or the monohydrate may be used; but acid containing 10 per cent. of sulphuric anhydride gives less satisfactory results than the weaker acid. For most purposes, it is sufficient to allow the liquid to drain away from the crystalline magma and then to wash the crystals with acetic acid until they are nearly free from colour ; but the acid can be further purified by recrystallising i t either from acetic acid or from ethyl acetate; it separates from the latter solvent in large, trans- parent prisms.Our observations serve to confirm Reychler's state- ments as to the physical properties of the acid. CamphorsuZphochZoride.--TnTe have found that the melting point and rotatory power of this compound are not altered by repeatedly recrys- tallising it from ether, chloroform, and light petroleum ; nor were they different when the acid used in preparing i t was recrystallised four times alternately from acetic acid and ethyl acetate. Constants.-[ u?: + 31 -1' (Solv. - chloroform ; c - 10 grams per CarnphwsuZpho6romide (n. sp.").-In preparing this, it is necessary to work with moderately small quantities, t o use a slight excess of the potassium salt rather than of the pentabromide, to leave the liquid pro- duct until firm and solid, and to avoid all local heating when the product is ultimately ground up with crushed ice; if these precautions be not observed, and especially if excess of pentabromide be used, the yield is very small and the product impure.The sulphobromide can be purified by recrystallising it from dry ether, from which it separates in large, four-sided tablets. I n working with large quantities, the wet substance may be dissolved in chloroform, and the solution having been dried by means of calcium chloride, the sulphobromide is pre- cipitated by adding light petroleum after distilling off as much as possible of the chloroform.Constants.-M. p. 9 3 O [ u]F + 26.0' (Solv. - chloroform ; c - 10 grams per 100 c.c.). * These letters are affixed so as to indicate the new compounds deecribed in the paper. All the compounds which are described were analysed : the results which were obtained are expressed by the formuls which are given. As the substances are all well defined, and are related t o each other in a very simple manner, no question can arise as to the interpretation which should be given to the results, and the numbers are of no independent value: to aave space, therefore, the analytical values are omitted.-[H. E. A.] 100 C.C.).1448 ARMSTRONG AND LOWRY : SULPHONATION OF Carnphorsulphoncide, C,,,H,,O*SO,-NH,, is only formed by the interaction of the siilphochloride and ammonia when a concentrated solution of the latter is used and the action is allowed to proceed violently; even then, the amide is always mixed with more or less of the anhydramide described below, from which it is distinguished by its moderate solubility in hot water.To separate the two compounds, the crude product is boiled with a little water ; the undissolved part is almost pure anhydramide, but the substance which separates from the aqueous solution as it cools is still impure and must be recrystallised at least twice. The amide is also produced when a-bromocamphorsulphonamide is reduced with zinc dust and acetic acid. Constants.-M. p. 132' (Reychler, 127'). [a]'D7" + 1 - 5 O (Solv. - chloroform, c - 10 grams per 100 c.c.).The b. p. of 7.099 grams of benzene was raised 0.158' by 0.1145 gram, 0.406' by 0.3795 gram, 0.588' by 0.6975 gram :. Mol. wt. 272, 352, 446; calc. 232. Ca~~~ol.su~~Lonunh~dramide, CloH,,NSO,, is the sole product of the interaction of ammonia and the sulphochloride when a dilute solution of ammonia is used, even when the mixture is heated in the water- bath. It crystallises well from a large bulk of boiling alcohol. The conversion of camphorsulphonamide into this compound takes place under somewhat remarkable conditions, being readily determined by acids, whilst ordinary dehydrating agents are relatively ineffective. When the amide is merely covered with concentrated chlorhydric, bromhydric, or sulphuric acid, it soon dissolves, but the anhydramide separates from the solution in the course of a few minutes; it is of interest, as an indication of the strength of the acid, that the conver- sion of the amide into the anhydramide may be brought about in the course of a few minutes by boiling it with a concentrated solution of camphorsulphonic acid.Camphorsulphonamide crystallises unchanged from acetic anhydride. If it be heated above its melting point, gas (water vapour) is given off at about 170', and the liquid solidifies at about 200' and again becomes liquid when the melting point of the anhydramide is reached. Constants.-M. p. 223' (Reychler 220'). [a]F - 33.5' (Solv. - chloroform ; c - 5 grams per 100 C.C. The b. p. of 7.130 grams of benzene was raised 0.543'by 0.324 gram, that oE 6.958 grams 0.560' by 0.4650 gram, and that of 7.130 grams 0.760° by 0.7070 gram :.Mol. wt = 265, 280, 348 ; calc. 214. Camp~orsul23honucnilide, C,oH,,O-SO,*NHPh.-Reychler's observa- tion that only one anilide is produced by the interaction of aniline andCAMPHOR. I. CAMPHORSULPHONIC AClD (REYCHI'ER). 14 49 camphorsulphochloride is confirmed by our experiments. substance is obtained on reducing a-bromocamphorsulphonanilide. Constants.-M. p. 1 1 9 O . [ a ] r + 67.3O (Solv. - chloroform, c - 10 grams per 100 c.c.). Cccmphorsulphon-p-bromccnilide (n. sp.).-This compound may be pre- pared either by brominating the anilide just referred to, or from p-bromaniline. It is only slightly soluble in spirit, from which it crys- tallises in flat needles, but somewhat more soluble in acetic acid.Constants.-M. p. 167'. [ a]1;' + 56.4' (Solv. - chloroform ; c - 10 grams per 100 c.c.). Camphorsulpho~iperid~d~$.--Of the two isomeric piperidides formed by the interaction of piperidine and camphorsulphochloride, the more soluble is produced only in small quantities, and we have not succeeded in altering the conditions so as t o effect any noticeable alteration in the proportions in which the two substances are formed. The less soluble-which is the principal product-can also be prepared by reducing a-bromocamphorsulphopiperidide, and on this account is prob- ably the normal piperidide, C,,H,,O~SO,-NC,H,,. As the tmo piper- idides do not undergo change into each other when digested with con- centrated chlorhydric acid, they cannot well be stereoisomerides.Carnphorsulphopiperidide ('2) (n. sp.).-Constants.-M. p. 140'. [ a ] : + 32.2 (Solv. - chloroform ; c - 5 grams per 100 c.c.). The piperidide crystallises from dilute spirit in long, glistening needles. It was obtained from a solution in acetone in stout, glistening crystals which were measured with the following results : The same System.-Orthorhombic. Axial ratios.-a : b : c = 1.1 722 : 1 : 0.8978. Poorrn8 present.-a{ loo), c{OOl}, p { 1 lo], r{ 1011, p{O1 l}. The form p(O11) was observed only twice and the form ~(001) is frequently missing. Ha6it.--Stout prisms, slightly elongated along the b-ixis and often flattened parallel to a face of the form ~(101). VOL. LXXXI.1450 ARMSTRONG AND LOWRY : SULPHONATION OF Angles observed. (CT =loo : l 0 j rr =I01 : 101 re =lo1 : 001 rr = l o 1 : I01 ac =100:001 ap =loo : I10 pp =110 : 110 pq = 110 : 011 r p = l o 1 : 110 rq = l o 1 : 011 r p = l o 1 : 110 Limits.Number of observations. ___ 30 6 10 15 6 26 14 24 2 2 19 ~ ~~ 1 52'18'- 52'55' 1 105 4-105 20 1 37 13- 37 42 I 74 17- 75 9 89 50- 90 7 I 49 15- 49 50 80 40- 81 5 66 27- 67 3 ~ 59 26- 59 40 ' 115 55 -113 33 j 53"48' Mean. 52'33' 105 12 37 27 74 46 89 58 49 32 80 50 66 45 53 48 59 33 113 15 Calculated. - 105" 6' 37 27 74 54 90 0 80 56 66 45 53 48 59 27 113 15 - isoCamphorszc~hopiperidide ( 1 ) (n. sp.).-Constants.-M. p. 56'. [ a]r + 3 3 . 6 O (Solv. -chloroform ; c - 10 grams per 100 c.c.). This compound is excessively soluble in almost all solvents; it can be obtained in large, transparent crystals by allowing its solution in dilute alcohol to evaporate slowly. Brilliant crystals were obtained from light petroleum which were measured with the following results : System,- Orthorhombic.Axial rcctios.-a : b : c = 1*1080 : 1 : 0.9814. Forms present.-af100), c(OOl), p(110), ~(101). The form ~~(100) Habit.-Usually stout crystals flattened parallel to a face of the is always small and frequently absent. form ~ ( 1 1 0 ) . Number of observed* 1 I cr = O O l : lo! rr =I01 : 101 ar = l o 0 : A01 rr =lo1 :A01 i p p = 110 : 110 p p =110 : 110 cp =001: 110 p r =110 : J O l pr = 110 : 101 24 11 8 12 8 8 16 32 20 Limits. ~ 41" 2'- 41O.58' 82 47 - 83 20 47 59 - 48 52 96 48- 97 16 84 5 - 84 22 63 27- 63 52 95 42- 95 55 116 0-116 37 89 50- 90 12 Mean. 41"32' 83 0 48 26 97 0 84 10 95 50 63 38 116 20 89 59 Calculated.I 83" 4' 48 28 96 56 84 8 95 52 116 22 90 0 -CAMPHOR. I. CAMPHORSULFHONIC ACID (REYCHLER). 1451 a-~1.oniocamp?~orsuZ~~onic Acid (n. sp.). a-Bromocamphor and a-chlorocamphor are readily sulphonated by means of a mixture of acetic anhydride (4 mols.) and sulphuric acid (1 mol.). The best results have been obtained by keeping the mixture duringa day or two at, atmospheric temperature, and then heating during two hours on a water-bath. Under these conditions, 80 or 90 per cent. of the material is sulphonated, but if the heating be prolonged, a large amount of insoluble matter is produced, and it is very difficult to purify the product. When sulphonation is effected, the cold mix- ture is poured into water, the solution then filtered and boiled for several hours with animal charcoal until the greater part of the acetic acid has been volatilised, when the liquid is again filtered%d neutralised with lime.The calcium salt separates from the properly concentrated solution ; if the product be brown in colour, the colour may be partially removed by washing the salt with spirit before recrystallising it. CuZciurn a-6romocumphorsuZpAonnte, (C,oH1404SBr),Ca + 6H,O, crys- tallises from hot water in pearly scales or in flat, transparent plates; it dissolves readily in hot, but only sparingly in cold water. Potassium a-brornocamp?~orsuZp?~onucte, C,,H,,OBr *SO,K + 4H20, crys- tallises from water in transparent, efflorescent tablets, and is more soluble than the calcium salt. a-Brornocu~pl~o~suZp~oc~Zo~ide, C,,,H,,OBr*SO,CI, dissolves readily i n chloroform and ethyl acetate, but less readily in ether and benzene ; it separates from these solvents in large, transparent prisms.It is an exceedingly stable substance, which can be kept during several months without undergoing change. Constants.-M. p. 65'. [u]: + 104" (Solv. - chloroform ; c - 10 grams per 100 c.c.). a-Bromoc~rnphorsuZphobrornide.-This compound is less stable than the chloride, undergoing hydrolysis slowly when exposed t o the air. If it be heated above 130°, it decomposes into sulphur dioxide and ap-dibromocamphor (m. p. 11 5O). Constants.-M. p. 61'. [a]? + 119" (Solv. - chloroform; c - 4 grams per 100 c.c.). a-BromocclcmioirorezlZphonarnide.-This compound crystallises from hot water or spirit in needles.When reduced by means of zinc dust and acetic acid, it yields camphorsulphonamide (m. p. 132'). When boiled with acetic anhydride, it is converted into the anhydramide ; a dibromo-derivative of the anhydramide is obtained when it is sub- jected to the action of bromine. 5 ~ 21452 ARMSTRONG AND LOWRY : SULPHONATION OF Constants.--M. p. 156O. [ U]T + 106' (Solv. - acetone ; c - 5,grams a-Brornoc~~phorsulp~anilide dissolves very readily in spirit, from Constants.-M. p. 106". [a]: + 177" (Solv. -chloroform ; c - 4.2 a-Bromocam~horsu~ho~ipe~id~~e separates from spirit in prismatic Constants.-M. p. 123'. [ u]F + 1 11' (Solv. - chloroform ; c - 3 per 100 c.c.). which i t crystallises in minute, felted needles. grams per 100 c.c.). crystals. grams per 100 c.c.). On reduction, it yields the piperidide melting at 140'.a- Chlorocanap~~su123T~onic Acid (n. sp,), Calcium a-Chlorocamphorsulphonate, (C,oH,404SC11),Ca t GH,O.-This salt crystallises from hot water in pearly scales. The barium salt, which is less soluble than the calcium salt, crystal- lises from hot water in minute, white scales. The potassium salt re- sembles that of the bromo-acid. The ammonium salt, although very soluble in water, may be obtained in large, glistening, transparent plates by allowing the solution to evaporate spontaneously. a-Chlorocam~hol.sul?~ochloride separates from ether in large, trans- parent crystals, which remain unchanged on exposure to the air. Constants.-M. p. 60". [a]:'" + 80.8O (Solv. - chloroform ; c - 5 grams per 100 c.c.).a-~~~orocam~horsu~~~~o~rorn~de,--Th~s compound was but partially examined. I t decomposes, when heated, into sulphur dioxide and a chZorobromocamp?kor melting a t 9s" ([.ID + 69*7'), agreeing in its pro- perties with that obtained by crgst,allising until the melting point and rotatory power were unchanged the pa-bromocblorocamphor pre- pared by heating a-chlorocamphor with bromine in sealed tubes (Lowry, Trans., 1898, 588). a-ChEorocnmphorsu123E.onccmide crystallises from hot water or spirit in needles. On reduction, by means of zinc dust and acetic acid, i t yields camphorsulphonanhydramide (ni. p. 223'). It is converted into the chloranhydramide by acetic anhydride, and on chlorination affords the dichlori-tnhydramide. Conetants.-BL p. 141". [a]F -+ 83.2' (Sdv.- acetone ; c - 6 grams per 100 c,c.),CAMPHOR. 1. CAMPHORSULPHONIC ACID (REYCHLER). 1453 Derivatives of Cumphorsul~~honan~ydrtcmitle contnining IIdogen (n. sp. >. The anhydride of camphorsulphonamide, described on p. 14-18, is the parent member of a series of compounds of which no fewer than eight have been isolated; in the majority of cases, the sulphonamides and the sulphonic acids from which these are derived are unknown, the anhydramide being the only derivative which has been prepared. The anhydramides are invariably produced when the sulphonamides are acted on by halogens, the substitution being accompanied by loss of the elements of a molecule of water. In the cases in which stereo- isomerism is possible, two compounds are usually produced ; in other cases, but one is formed, and whilst only one compound is produced when the anhydrides are made from the sulphonamides by the action of acetic anhydride, when t h e dehydration is effected by mineral acids, a mixture of stereoisomerides may be formed. Stereoisomerides con- taining two different halogen atoms are obtained as isomorphous mixtures, but those containing a single halogen atom are not iso- morphous, and can be separated in the ordinary way by fractional cry stallisation, a-Bromocc~mphorsulphonunh?/drumide, CloH1,O,NSBr.-This compound is a very well-defined substance.It was first obtained by us by subject- ing camphorsulphonamide, dissolved in acetic acid, t o the action of bromine at about looo, and crystallising the product 15 times from spirit, acetic acid, and acetone.It was subsequently prepared by heat- i ng a-bromocamphorsulph onamid e wit h concentrated brom hyd ric acid. Theee methods usually give rise to a mixture of stereoisomerides ; t h e a-compound, however, is the sole product when a- bromocamphorsulphon- amide is heated with acetic anhydride. Jt separates from spirit and acetic acid in flat needles, and from acetone in orthorhombic prisms or tablets ; on reduction, i t yields camphorsulphonanhydramide(m. p. 2 2 3 O ) . [ u]gp + 99m30(Sol~. - acetone ; c - 5 grams per 100 c.c.).' This value is that obtained with the substance prepared by the third of the methods described above; that prepared by the first method gave [a]? + 97.8, and t h a t prepared by the second gave Constants.-M. p.186'. [ a ] F +9s*g0. The crystals were examined with the following results : System. -0rt horhom bic. Axial ratios.-a : b : c = 1.4659 : 1 : 2.1519 = 1 : 0.6821 : 1,4680. Porms p*ese.nt.-aflOO}, c(OOl}, q{O11}, r(101}, r'{ IOZ), p(1 lo}. Habit.-Usually prisms elongated along the a-axis, but sometimes tabular crystals in which the face q is largely developed, or in prisms1454 ARMSTRONG AND LOWBY: SULPHONATION OF elongated along the axis of 6. The dominant forms are c, p , and q ; the forms a and r are only occasionally observed. Angles observed. c : 'I (001) : ( O l l ) (7: q (011): (011) p : q (110) : (Oil) p: q (110) : (011) p : c (110):(001) q : T' (011) : (102) q:r'(Oll) :(l02) c : r' (001) : (102) r': r' (102) : (102) u : r' (100) : (102) T : r' (101) : (102) a : ?- (100) : (101) p : r (110 : (101) q : r (011) : (101) q : r (011) : (101) - Number I f obser- vations.24 14 2 .t 29 12 4 4 15 7 2 2 1 1 3 2 ~~ Limits. 64O49'- 65"19' 49 3 9 - 50 6 41 20- 41 36 138 24 -i38 41 89 52- 90 6 70 2 - 70 8 109 51-110 1 107 17 -107 31 53 31 -*53 46 19 27 - 1 9 40 34" 6' 62 17 36 5- 36 34 76" 8'- 76"20' 103 30 -103 47 Mean. 65" 44' 49 52 41 29 138 31 90 0 70 5 109 54 36 17 107 26 53 38 19 33 34 6 62 17 76 15 103 38 Calc. - 49'51' 138 31 90 0 70 8 109 52 36 17 107 26 53 43 19 27 34 16 62 15 76 16 103 44 - Angles of l,oH,,OCIBr, 64'53' 50 14 41 38 138 22 90 0 69 56 110 4 36 2 107 56 53 38 19 28 34 30 62 17 76 5 103 55 Optics; properties.-The plane of the optic axes is*(OlO), the axis of cc is the acute bisectrix, and the optic axial angle is large.An optic axis is seen emerging through each of the faces of the form ~'{102}. The crystals exhibit a very striking similarity t o those of &a'-di- bromochlorocamphors (Trans., 1898, '73, 585), as may be seen on com- paring the axial ratios and also the angular measurements in the last two columns of the above table. CloH,,O,NSBr, 1.4659 : 1 : 2.1519 = 1 : 016821 : 1.4680, C,oH,,C)CIBr,, 1.4661 : 1 : 2.3332 = 1 : 0.6821 : 1.4550. The resemblance is far closer than that which exists between com- pounds so closely related as aa'-dibromocamphor and aa'-bromochloro-CAMPHOR. I. CAMPHORSULPHONIC ACID (REYCHLER). 1455 camphor, and is all the more remarkable because there is no similarity of structure apparent in the compounds. The chief difference between the crystals is one of habit : the dibromochlorocamphors usually crys- tallise in prisms elongated along the b-axis, whilst the anhydramide is usually developed along the a-axis.It may also be pointed out that in these crystals the ratios a : b and c : a are almost identical, and that the c : a ratio agrees closely with that of the dichloranhydramide described on p. 1457, although the latter differs widely in the u : b ratio. C,,H,,O,NSBr, a : b = 1.4659 : 1. c : a = 1.4680 : 1. CloH,,OCIBr,, u : 6 = 1.466 1 : 1. C,,H,O,NSCI,, c : a = 1 *45 10 : 1. a'-B.).omocam~horsuZ~~onanhydrum~d~, -On one occasion, in attempt- ing t o prepare the compound just described by brominating camphorsul- phonamide, a product was obtained melting at 166O and of considerably lower rotatory power, [ a]y + 4 0 ~ 5 ~ (Solv.- acetone, c - 5 grams per 100 c.c.). A similar product was obtained by subjecting a-bromo- camphorsulphonamide to the action of bromhydric acid. The values obtained on analysing these products showed them to be identical in composition with the a-anhydramide, and there can be little doubt that i t is the stereoisomeride. Usually, when the second method is adopted, a mixture is obtained the melting point of which is near t o 166qalthough the compound melting a t 186'may be its chief constituent. The character of the product is easily ascertained by determining its rotatory power. a-Chlorocanaphorsulphonanhydramide, CloH,,O,NSC1, was first ob- tained on attempting to chlorinate chlorocamphorsulphonamide. It is readily formed on heating a-chlorocamphorsulphonamide either with acetic anhydride or with chlorhy dric acid.It crystallises from spirit or acetic acid in long, silky needles which are often several centimetres in length ; it is more soluble in acetone than the bromo-compound, and crystallises from this solvent in large, orthorhombic tablets. [ a]F + 59*5O (Solv. - acetone ; c - 5 grams per 100 c.c.) and 61.2'. The latter value is that found in the case of the substance prepared by the acid method, the former that of the product obtained on attempting to chlorinate the amide. The action of chlorine on camphorsulphonamide was not studied so fully as that of bramine, owing to the great difficulty of regulating the degree of chlorination, I n almost every case, the dichloranhydr- c : u = 1.4550 : 1.Constants.-M. p. 167O.1456 ARMSTRONG AND LOWHY: SULPHOlYATlON OF amide was produced ; but on one occasion a substance was separated by fractional cry stullisation, melting at 147O, of low rotatory power, [ a ] r + 16.9", which was probably an isomeride of the a-anhydramide. The crystah of a-chlorocamphorsulphonanhydramide were examined with the following results. Owing t o the small number of measure- ments made, the axial ratios may be incorrect to the extent of a few units in the third decimal place. A!ystem.-Orthorhom bic. Axicd ratios.-a : b : c = 1.589 : 1 : 1.022. Fo~rns present.--Q(100}, b(0101, c(OOl}, r(101), pi1 10). Angles observed. ?lumber of observations. Mean. Calculated. a : r 1OO:lOl 9.: c 101 : 001 a : c 100 : 001 a : p 100 : 110 p : b 11O:OlO a : b 100:010 57"15' 32 43 90 0 57 49 32 11 90 0 - 32"45' 90 0 32 11 90 0 - Optical properties.-There is a good cleavage parallel to the form a{100), and an optic axial figure can be seen through the cleavage face.The optic axial plane is parallel to b(010), and the acute bisectrix is parallel to the axis of a. The optic axial angle is small and the double refraction positive. No very close relationship exists between the axial ratios of the chloro- and bromo-compounds. Most probably the value taken for the c-axis of the bromo-compound should be halved to render the measure- ments comparable, thus : a-Bromanhydramide ... ... .. 1.4659 : 1 : 1.076 a-Chloranhydramide ......... 1.589 : 1 : 1.022CAMPHOR. I. CAMPHORSULPHONIC ACID (REYCHLER). 14.57 l - 69" 9' 19 28 36 1 55 25 110 51 90 0 53 59 63 42 58 9 107 26 64 44 - Of the four anhydramides containing two halogen atoms, two aye ob- tained as isomorphous mixtures, two of the products appear to be single substances. aa'-Diclzlorocam~horszc~lzonccn~ydi.amide may be prepared by chlorin- ating either camphorsulphonamide, or a-chlorocamphorsulphonamide, or a-chlorocamphorsulphonanhydramide : the amide is dissolved in acetic acid and the liquid heated on a water-bath while a n excess of chlorine is passed into i t ; on allowing the solution to cool, the di- chlornn hydramide separates in large, transparent prisms or needles, n nd when recrystallised from spirit or acetic acid forms long, silky needles melting at 172'.When the substance is repeatedly recrystallised, the melting point rises to 1 7 6 O , but the rotatory power remains constant at [aID + 6 O ; the product is therefore t o be regarded as a single substance and not as an isomorphous mixture.The compound is reduced by zinc dust and acet'ic acid to camphorsulphonanhydramide (m. p. 223'). The following measurements were made of crystals of the dichlor- anhydramide deposited from acetone. System.-Orthorhombic. Axid rcctios.-a : b : c = 1,1096 : 1 : 1.6097. ~'ormspresent.-a(lOOt, c{OOl), r { l O l ) , r'{102), q = { O l l t . Hubit.-Prisms elongated along the b-axis. 110 46 90 0 53 58 63 40 5s l C 107 27 72 34 Limits. a : r 1OO:lOi r : r 101 : l o 1 I r : r' 101 : 102 c : r' 001 : 102 r : r 101 : l o 1 ~ n : c 100:001 :.I" 1TJO : 102 q : q 011 : o i i c : q 001:011 q : r 011:lOl q : r 011 : i o i q : r' 011 : 102 q : rr 011 : 102 a : q 1 O O : O l l , c : r 001 :I01 j I ' _ _ _ _ _ 27 13 15 21 , 8 I 19 1 2 24 11 1 9 ' I! 1 11 14 I 34"lgr- 34"53' 63 40- 69 31 19 1 3 - 19 31 35 48- 36 3 55 9 - 55 45 110 36 -110 53 89 25- 90 24 53 49 - 54 6 63 34 - 63 49 57 59 - 58 26 107 1 3 ---lo7 41 72 6 - 72 53 64 38 - 64 54 115 0-115 21 89 48- 90 8 Calculated.1458 AHMSTRONG AND LOWRY : SULPEONATION OF 0pticaZpoperties.-An optic axial figure can be seen through the faces of the form c{OOl).The optic axial plane is (010) and the axis of c is the acute bisectrix; the optic axial angle is small, the disper- sion is strong, u>p, and the double refraction is negative. aa'-Di bromoctLmphorszclphonanhyclranzide, C,,,H, ,02NSBr2, is best prepared by adding an excess of bromine t o a solution of cam- phorsulphonamide in acetic acid, and heating during several hours on the water-bath; it can also be prepared in a similar manner From a-bromocamphorsulphonamide and from the two isomeric brom- anhydramid es.It crystallises from acetic acid or spirit in long, silky needles. When reduced, i t yields camphorsulphonanhydramide. As specimens prepared by different methods had the same rotatory power, i t is probable that a single substance, not an isomorphous mixture, is produced. Constants.-M. p. 195'. [ a]r - '7.2" (Solv. - acetone ; c - 5 grams per 100 c.c). Dibromocamphorsulphonanhydramide crystallises from acetone in The following results were obtained in measur- transparent prisms.ing the crystals. 8ysfem.- Orthorhombic. Axicd vutios.-a : 6 : c = 1.8981 : 1 : 1.8202 = 1.0428 : 0.5494 : 1. ~ormspi.esent.--cc{lOO), c(OOl), q(O11 f , q'{Ol2),p(llO), o ( l l l ) , e.{101), The form o f l l l } , which is not shown in the figure, truncates Hubit.-Usually prisms elongated along the b axis, but also tabular r'{lO2}. the corners formed by the faces p (I r. crystals in which the form ~ ( 1 0 0 ) predominates.CAMPHOR, I. CAMPHORSULPHONIC ACID (REYCHLEK). 1459 Angles observed. Q : T (100) : (101) c : r (OOl):(lOl) r : r (101) : (101) a : T' (100) : (10'2) c : r' (001) : (102) r ' : r' (108) : (~102) r : r' (101) : (102) a: : e (100) : (001) c : q (001) : (011) q : q (01 1) : (011) c : q'(OO1) : (012) 2': 4' (012) : (012) q : 4' (011) : (012) a :p (100) : (110) p : p (110) : (110) p : p (110):(110) a : q (100):(011) a : q' (100) : (012) c : p (001) : (110) p : 0 (110) : (111) c : 0 (001) : (111) q : r (011) : (101) q : p (011) : (110) p : r (110):(101) r': q (102) : (011) p : 0 (011) : (111) o : r' (1 11) : (102) p : q' (110) : (012) T': 4' (102) : (012) r':p (102) : (110) q': 1' (012) : (101) 0 : q' (110) : (012) 0: T (111) : (101) 0:T'(lll):(lo2) 0 : T' (111) : (102) Number of observations.30 23 14 35 25 15 30 26 25 12 27 11 14 16 8 8 4 4 4 1 1 6 4 4 4 2 2 4 4 4 2 2 2 1 1 Limits. 30" 1'- 46"29' 43 33- 44 2 92 5- 92 44 64 8- 64 37 25 2t- 25 51 51 4- 51 24 17 58 - 18 26 89 48 - 90 11 61 5 - 61 17 57 32 - 57 41 42 10- 42 25 84 28- 84 42 18 47 - 18 59 62 5- 62 19 55 31 - 55 40 124 16 -124 32 89 5 5 - 90 6 89 59- 90 3 90 0 - 90 1 25'56' 64 4 69'30'- 69"40' 39 12 - 39 21 71 7- 71 15 64 10- 64 15 54 52- 54 56 60 54 - 60 59 53 23 - 53 27 48 6- 48 17 78 19- 78 30 57 44 - 57 46 30 44 - 30 51 91 34 - 91 37 77035' 102 23 Mean.46'12' 43 48 92 28 64 24 25 37 51 13 18 10 90 0 61 12 57 36 42 18 84 36 18 54 62 13 55 35 124 26 90 0 90 0 90 0 25 56 64 4 69 35 39 15 71 11 64 13 54 54 60 56 53 25 48 11 78 24 57 45 30 48 91 36 77 35 102 23 Calculated. - 43048' 92 24 64 23 25 37 51 14 18 11 90 0 61 13 57 34 84 36 18 55 62 13 55 34 124 26 PO 0 50 0 90 0 25 55 64 5 69 40 39 10 71 10 64 16 54 El 60 53 53 27 48 10 78 23 57 44 30 49 91 37 77 42 102 18 - OpticaE p.ope&es.-An optic axial figure can be seen through tbe faces of the form a(100). The optic axial plane is (010) and the axis of a is the acute bisectrix; the optic axial angle is large, the dis- persion small, and the double refraction positive, aa'-ChZorobromocampho~szcZphonanhydrccmides were prepared by the action of bromine on a-chlorocamphorsulphonamide and of chlorine on U-bromocamphorsulphonamide. The product obtained by the former method separated in crystals from the acetic acid used as solvent in the bromination process, and when recrystallised from acetic acid was obtained in long, silky needles, which melted a t 172' ; [a]E + 7.8" (Solv.-acetone ; c - 5 grams per 100 c.c.). After it had been recrys- tallised seven times, the melting point rose to 173', [ a l D falling to + 4*3', and after thirteen crystallisations the melting point was 1 7 4 O , Fa], + 2.4'.The product obtained by the action of chlmine on a-bromocamphor- sulphonamide cryfitallised well from the acetic acid, and when recrys-1460 ARMSTRONG AND LOWRY: SULPHONATION OF tallised from acetic acid was obtained in white needles, which melted at 192O, the value of [a]"" being - 38.3' ; after six crystallisations, the melting point was 194O, and [ It will be noticed that the products obtained in the two ways differ very considerably in their properties, and to a far greater extent than is observed in the case of the corresponding chlorobromocamphors. This may be accounted for on the assumption that as the anhydramides no longer contain the CO group, they are lees liable t o undergo stereoisomeric change than are the compounds in which this group is present.On this assumption, the product in each case consists mainly of the compound formed by direct substitution. A similar explanation may be given of the stability of the isomeric bromocamphorsulphon- an hydramides. The following results were obtained on measuring crystals of the bromochloranhydramide prepared by the action of bromine on a-chlorocamphorsulphonamide : - 42.2'. System.-Orthorhombic. Axial ratios.-a : b : c = 1.9014 : 1 : 1.8369 = 1,0351 : 05444 : 1. ~ormspresent.-a{lOO), c{OOl}, r{101), ~'{102}, q{o11}, q'{012}, ~ ( 1 1 0 ) . Habit.-From acetone prisms elongated along the b axis or stout tablets in which ~ ~ ( 1 0 0 ) is the dominant form. Angles observed. u : r 1 O O : l O l n : r' 100 : 102 c : T' 001 : 102 r:r'lOl :lo- q : p 011:011 c : q' 001 : 012 g : q' 011 : 012 p : p 110 : i i o a : p 100 : 110 Number of observations. 4 21 20 5 11 26 22 18 9 Limits.Mean. 45'49'-46" 1' 64 1 - 6 4 30 25 36-25 37 17 55 -18 41 42 17 -42 56 18 26-19 1 62 5-62 29 55 21 -55 37 57 8 - 5 i 21 ! 45"58' 64 13 25 47 18 11 57 13 42 34 18 48 62 16 55 29 Calculated. 45"59' 64 13 18 14 57 8 18 52 62 16 55 29 - -CAMPBOR. I. CAMPHORSULPHONIC ACID (REYCHLER). 1461 Optical popertie8.--dn optic axial figure can be seen through the form a(100), the acute bisectrix being parallel to the axis of a, and the optic axial plane perpendicular to the axis of b. The optic axial angle is very large, and the dispersion is too slight to be noticeable. The double refraction is positive in sign. The results obtained on measuring crystals of the isomeric chloro- bromanhydramide prepared by the action of chlorine on a-bromocamphor- sulphonamide were as follows : 8ystem.-Orthorhombic. Axial ratios.-a : b : c = 1.8873 : 1 : 1.8099 = 1.0506 : 0.5521 : 1. Rorms present.--a(1OO}, c(OO1}, r'(102}, p { l l O ) , q(O11}, q'iO12;. Habit.-From acetone brilliant prisms, elongated along the axis of b. Angles observed. a : T' 100 : 102 c : r' 001 : 102 q : p 011 : 011 c:q'001:012 q:p'011:012 a : p 1 0 0 : ~ l O p:p 110 :110 Number of observations. 26 22 3 12 9 21 12 Limits. 64"12'-64'31' 25 26 -25 43 57 49-58 2 4'2 1-42 14 18 45 -19 0 61 55 -62 30 55 313 -55 57 Mean. 64"22' 25 38 57 54 42 6 18 58 62 5 55 50 Calculated. - 25'38' 57 48 42 10 18 56 55 50 - Opticcd poperties.-An optic axis can be seen emerging through the faces of the form r'{102), the optic axial plane being perpendicular t o the axis oE b. The optic axial angle is very large, amd a complete optic axial figure was not observed ; the position of the acute bisectrix and the sign of the double refraction were therefore not determined. The optic axial dispersion is very slight. The properties of the four disubstituted anhydrnmides are summar- ised in the following table, a pair of values indicating the effects of fraet ional recrys tallisa t ion :1462 ARMSTRONG AND LOWRY: SULPHONATION OF Dibromo- ............... Chlorinated hromo- ... Brominated chloro- .. Dichloio- ............... Anhydramide. 1 M. p. [a], (Acetone). 1 Axial ratios. 195" - 7-20 1.8981 : 1 : 1'8202 192" t o 194" 1.8873 : 1 : 1'8090 172 to 174 +7*8" to +2'4" 1.9014 : 1 : 1'8369 172 t o 176 + 6" 1'1096 : 1 : 1.6097 -38'3" t o -42'2" It will be seen that the chlorination product melts at about the same temperature as the dibromanhydramide, whilst the bromination product resembles the dichloranhydramide. The rotatory powers of the chlorobromanhydramides lie outside the limits of the dichlor- and dibrom-anhydramides, an effect which may be ascribed to the asymmetry of the a-carbon atom when linked to two different radicles. The crystallographic data are somewhat striking : the first three members form a very close isomorphous series, the axial ratios of the dibrom- being intermediate between those of the chlorobrom-anhydramides, but the constants of the dichloranhydramide belong to an altogether different series, approaching somewhat to the monochlor- and mono- brom-anhydrsmides. It is not improbable that in this case we are dealing with an isodimorphous series.

ISSN:0368-1645    

DOI:10.1039/CT9028101441

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1462 ARMSTRONG AND LOWRY: SULPHONATION OF CXLIIL-Studies o f the Tapenes and Allied Compounds. The Xulphonation of Camphor. 11. B-Brorno- camphor and its heifiivatives. $-B~*omocumphoric Acid. By HENRY E. ARMSTRONG and T. MARTIN LOWRY. IN seeking to determine the constitution of the Reychler camphor- sulphonic acid and of the other acids described in the previous communication, we naturally availed ourselves of the method used with such brilliant success in our laboratory by Kipping and Pope, which led them to discover the r-series of derivatives of camphor. It was t o be expected that if the Reychler acid were an a-derivative, its sulpho- chloride and sulphobromide would be decomposed by heat and give rise to ordinary a-chloro- and a-bromo-camphor respectively. The earlier experiments made from this point of view were unsatisfactory, and later experiments have shown that the decomposition takes place in a normal manner only under certain conditions.No difficulty was experienced in preparing a dibromocamphor fromCAMPHOR. 11. &BROMOCAMPHOR AND ITS DERIVATIVES. 1463 the bromide of the a-bromocamphorsulphonic acid prepared by Reychler's method (p. 1451) ; the compound so produced, however, was not the ordinary a-derivative but the /3-compound which was first prepared by Swarts and subsequently investigated by Knchler and Spitzer. Kachler and Spitzer had found that the ,@compound gave rise t o a dibromonitrocamphor when nitrated, so that there could be little doubt that only one of its bromine atoms was present in the a-position ; but as Swarts had shown that a-dibromocamphor was converted into the isomeride by merely heating it with hydrogen bromide, it was not improbable that the somewhat drastic treatment to which the sulpho- bromide was subjected had led to the transfer of a bromine atom, and the production of /3-dibromocamphor i n such a manner could not be regarded as final proof that the sulphonic group was not in the a-position, As the constitution of ,3-dibromocamphor had not been determined, we undertook the further investigation of this compound, and succeeded in obtaining from it a P-bromocamphoric acid isomeric with the w-acid investigated by Wreden, in which bromine displaces the tertiary hydro- gen atom in camphor, and also with the isomeric r-acid discovered by Kipping, in which bromine displaces hydrogen in one of the median &ethyl groups.The discovery led us t o persevere in the attempt to prepare P-bromocamphor from the Reychler acid, and i t was soon found that a '6 normal "mdecomposition of the sulphobromide could be effected by heating it rapidly, in quantities of 10 grams at a time, in test-tubes over the bare flame, but that if heated slowly it gave rise only t o '' condensation " compounds. Thus 30 grams of sulphobromide decomposed with great care by simply heating it under reduced pressure at 130°, gave no trace of bromocamphor. The amount formed, however, was small under all conditions. The bromocamphor obtained from the sulphobromide melted at about the same temperature as the ordinary compound, but a mixed melting point at once revealed a difference, a mixture of the two substances melting below 70" instead of at 76O; as it gave P-bromocamphoric acid on oxidation, there was no doubt that the new product was the hitherto unknown P-bromo- camphor.d great improvement in the method of preparing this P-compound was ul tiwately effected by carrying out the decomposition of the sulphobromide in a solvent. The discovery of P-bromocamphor must be credited, however, not only t o us, but also to Dr. Forster, who obta-ined it by the direct action of bromine on the compound which he originally described as hydroxy- camphene (compare Proc., 1901, 17, 245). Although his method is a more tedious one than ours, and gives a smaller yield, i t has the advantage of being applicable to the preparation of P-chlorocamphor,1464 ARMSTRONG AND LOWRY : SULPHONATION OF which we have r o t yet succeeded in preparing from camphorsulpho- chloride.P-Bromocamphor(n. sp.).-In preparing this substance, the formation of condensation products can be very largely avoided by carrying out the decomposition of camphor sulphobromide in a solvent of high boiling point, especially if a large quantity of solvent be used, Commercial xylene has proved to be an eminently suitable liquid, as its boiling point ( 1 3 7 O ) is just above the temperature (130') a t which the decomposition takes place, and it may readily be separated by means of steam. The following method allows of the preparation of P-bromo- camphor in quantities of 50 grams a t a time and with relatively little trouble; the operation lasts two days, but i t is not difficult to obtain about 50 grams of product each day.Four quantities of 40 grams of dry potassium camphorsulphonate are each ground in a mortar with 63 grams of phosphorus pentabromide; the liquid is left until it becomes a firm solid. Finely divided ice is then carefully added, together with a little sulphite t o remove bromine .; the white, powdery sulphobromide is ultimately drained on the filter-pump and then dissolved in xylene. The xylene, of which about 500 grams are required for 160 grams of potassium salt, is separated from water and the solution is left overnight in contact with calcium chloride. TO effect the decomposition, the dry solution is boiled in a Jena flask over a small flame during about 20 minutes, and the hydrocarbon is then distilled off by passing a current of steam into the liquid. The xylene distils off very rapidly and is carried over with about its own weight of water; when most of the xylene has been removed, the rate of distillation is somewhat checked in order that the solid bromocamphor may be held back in the condenser, whilst a certain amount of xylene is still carried forward by the water.When the whole of the xylene has been removed, the receiver is changed and the distillation carried out rapidly; 1 gram of bromocamphor is carried over by about 50 grams of water, The yield of P-bromocamphor is usually about one- third of the weight of potassium salt used or about 40 per cent. of the theoretical quantity ; under the conditions described, the weight of non-voIatile condensation product is only about 20 per cent.of the weight of P-bromocamphor produced. Loss of material occurs almost entirely in preparing and handling the very unstable sulphobromide ; probably the weight of sulphobromide in the dried xylene solution is only 50 per cent. of the theoretical quantity, and of thia 80 per cent. is converted into /3-bromocamphor and 20 per cent. into condensation products. A smaller yield is obtained on the first occasion, as some 10 or 20 grams of bromocamphor are carried over with the xylene, but the full yield is obtained in subsequent experiments if the xylene beCAMPHOR. 11. &BROMOCBMPHOR AND ITS DERIVATIVES, 1465 used repeatedly. The properties of F-brornocamphor are in some respects very like those of the a-compound. Its melting point is only two degrees higher than that of the isomeride, but it has a much lower rotatory power.per 100 c.c.). We are indebted to Dr. Perkin, sen., for determination8 of the magnetic rotatory power and refractive power. Magnetic .rotatory power.-The substance was dissolved in ethylene chloride ; the solution contained 43.75 per cent. of the bromocamphor and its composition may be represented by the formula CloH1,OBr + 3C,H,C12. Bromine converts it into up-dibromocamphor. Constants.-M. p. 78". [a]y + 19.2' (Solv. - acetone ; c - 3.33 grams Relative density of solution : d 15"/15', 1,3082 ; d 25'/25*, 1,2984. The relative density of a similar solution of a-bromocamphor was d 15'/15O, 1.2993, or 0.0089 less (this vol., 310).Magnetic rotation (twice determined) : t Sp. rot. Mol. rot. 15.3" 1.2887 28-903 Less 3 mol. C2H,C1, 16.455 3101. rot. C,,,H,,OBr 12.448 This value is lower than that of a-bromocamphor, which is 18.761, the difference amounting to -0.313. A similar kind of difference was found to exist between ua- and ap-dibromocamphor, although in this case the difference only amounted to about 0.100 (this vol., 31 1). Ref~*active power.-This was determined with the aid of the solution in ethylene chloride, __ P I p d k?-Bromocamphor. a-Bromocarnphor. Diff. Ha ............... 87.756 88.083 0.327 H, ............... 89.480 89.872 0.39 1 H, ............... 90.517 90.919 0.398 I n both cases, the P-compound gives the inferior values; the superiority of the a-compound may be ascribed t o the cooperative influence exercised by the bromine atom and the ketonic group in contiguity./3-Bromocamphor separates from light petroleum in well-formed crystals, of which the following measurements were made : VOL. LXXXI. 5 F1446 ARMSTRONG AND LOWRY: SULPHONATION OF &,&em.-Orthorhombic. Axial ratios.-a : Z, : c = 1.062 : 1 : 0.822. -8"ormspresent.--cc{lOO), b{010), p{110), r(101). The form ~ ( 1 0 1 ) is always small and frequently absent. Ha6it.-Stout prisms, elongated along the axis of b, and often flattened into plates in which a(100) is the dominant form. Angles observed. a : r (100) :(101) : p (100) : (119) p : r (110) : (101) T : T (101) : ( i o i ) a : 6 (100) : (010) p : b (110) : (010) b : T (010) : (101) p : (110) : ( i o i ) .Limits. Number of observations. 18 10 14 11 11 4 2 2 56°37f- 52" 1' 76 13- 76 32 80 50- 90 15 46 34 - 46 55 43 6- 43 26 64 50 - 64 57 114 58-115 0 a9 5 6 - 90 7 Mean. 51"49' 76 23 90 0 46 43 43 16 90 0 64 53 114 59 Calculated. - 76'22' 90 0 46 44 90 0 64 42 115 18 - Optical properties.-A n optic axis emerges almost perpendicularly t o the faces of the form r(101) ; the optic axial plane is therefore parallel to the form b{OlO), the acute bisectrix is parallel to the c axis, and the optic axial angle is about 76'. The double refraction is positive in sign. The crystalline symmetry of P-bromocamphor is intermediate be- tween that of its isomerides ; thus 7r-bromocamphor crystallises in forms belonging to the tetragonal system, P-bromocamphor is ortho- rhombic, and a-bromocamphor is monosymmetric.afl-Bibi*omo-a'-nitrocarnphor,-As Kachlor and Spitzer have shown, this compound is the chief product obtained on heating ap-dibromo- camphor with nitric acid. The substance we prepared in this mannerCAMPHOR. 11. P-BROMOCAMPHOR AND ITS DERIVATIVES. 1467 crystallised from acetic acid in brilliant, transparent needles or prisms, but it was necessary to recrystallise it eight times from acetic acid t o free it from admixed tribromocamphor, and t o raise the melting point to that given by Kachler and Spitzer (139O). A very considerable amount of dibromonitrocamphor-apparently unmixed with tribromocamphor-is obtained on oxidising P-bromo- camphor with nitric acid. I n this case, the liberation of the necessary bromine must be due to the oxidation of the bromocamphor beyond the bromocamphoric acid stage.Constants.-[ u]F - 25.7' (Solv. -acetone; c - 4.74 grams per 100 c.c.). aa'P-(rribromoc~cm~l~or.-This substance was separated from the im- pure once-crystallised dibromonitrocamphor above referred to by reduc- ing the nitro-compound with absolute alcohol and the calculated amount of caustic potash. It remained as an insoluble residue, which was easily purified by recry stallisation from dilute spirit, from which it separated in long, white needles. The compound prepared by Swarts, by heating ap-dibrornocamphor with phosphorus pentabrornide, was doubtless this substance. To judge from the evidence afforded by a mixed melting point, it is isomorphous with the dibromochlorocam- phors obtained on brominating a-chlorocamphor (Lowry, Trans., 1898, '73, 731). Constants.-M.p. 66". [a]: + 2" (Solv. - acetone ; c - 2.42 grams per 100 c.c.). P-Bromocamphoric Acid, CsHI,Br(C0,H)2 (n. sp.).--'l'his acid is ob- tained on oxidising either P-bromo- or up-dibromo-camphor with nitric acid (d. 1-4). On evaporating the acid, i t separates as a crystalline powder, indistinguishable in appearance from camphoric acid, P-Bromocamphoric acid dissolves much more readily in nitric acid than in water, in which it is only slightly soluble ; i t does not crystal- lise well from organic solvents. The acid may be freed from neutral impurities, either by washing the crude substance with chloroform, or by dissolving it in dilute ammonia and precipitating with nitric acid.When heated, it softens a t about 205' and melts at 208-210°, liberating gas. I n its physical properties, the acid and its anhydride present a remarkably close resemblance t o T- bromocamphoric acid, but the two acids differ considerably in chemical properties. A solution of the ammonium salt is not precipitated by calcium chloride. A number of attempts were made to convert the acid into a camphanic or hydroxy- camphoric acid by heating its alkaline solution, but in no case was a product free from halogen obtained; the bromine atom appears to be f a r less readily displaced than is that in T-bromocamphoric acid.1468 ARMSTRONG AND LOWRY : SULPRONATION OF Constants.-[a]:" + 39.3' (Solv. - alcohol ; c - 5 grams per 100 c.c.) P-Bromocamphoric AniLydride (n.sp.).-This may be prepared by boiling a solut,ion of the acid in acetic anhydride during two or three minutes ; it crystalliscs magnificently from hot dilute acetone in long, glistening, flat needles. The anhydride has no acid action, and does not dissolve in a solution of sodium carbonate even when this is boiled for a few seconds. Constants.-M. p. 142'. [ a]g - 2.8' (Solv. - acetone ; c - 5 grams per 100 c.c.). rr-Bromocamphoric anhydride La]F - 37.4' (Solv. -acetone ; c - 43 grams per 100 c.c.). Monoinethyl Bvomocamphorate.-HHydrogen chloride was passed into a solution of the acid in methyl alcohol, and the liquid was then allowed to evaporate ; a stiff and sticky mass remained which was redissolved in methyl alcohol. The salt separated slowly in a crystalline form as the liquid evaporated. It was recrystallised twice from dilute methyl alcohol, and was then obtained in glistening, white flakes. Constants.-M. p. 140'. [a]: + 53.6' (So1v.-acetone ; c - 4.79 grams per 100 c.c.). isoCamphoronic Acid.-This acid was obtained on boiling P-bromo- camphor with nitric acid and silver nitrate until silver bromide was no longer produced ; as we have not been able to prepare it by oxidising P-bromocamphoric acid in a similar way, i t is probable that the latter acid is not the intermediate product of oxidation when silver nitrate is used. Our product formed beautiful, trans- parent prisms melting a t 166". The identity of the acid from bromo- camphor with isocamphoronic acid was directly proved by a com- parison of the angular measurements with the values given by Zepharovich (Tien, Akad. Ber., 1876, 73, i, 19) : Zepharovich. A. and L. o i f : 100 75'25' 75'25' 011 : 100 '74'57' 74'56' o i l : 100 67'6' 67O11

ISSN:0368-1645    

DOI:10.1039/CT9028101462

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年代:1902

数据来源: RSC

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CAMPHOR. III. OPTICAL INVERSION OF CAMPHOR. 1469 CXLIV.-Studies of the Teq-penes and Allied Compounds. The Xulphonation of Camphor. 111. The Optical Inversion of Ccmnphor und the Mechanism of Betem- and Meso- sulphoiaation, of Homo- and Hetero-brornanation, and of Dehydration. By HENRY E. ARMSTRONG and MARTIN T. LOWRY. THE formation of isocamphoronic acid, CH,X*CH(CMe,X)*CH,X (X = C02H), on oxidising P-bromocamphor, would appear t o be almost conclusive proof that the bromine atom is not present in a methyl group; consequently, of the two formulae which, as Forster has pointed out (this vol., 267), account for the conversion of P-bromo- camphor into campholenic acid by the action of alcoholic potash, that which he preferred is to be regarded as highly probable, namely : CH,-YH-CH, CHBr-CMe-CO I p 2 1 .It is improbable that both of the c 6 pentaphane ’ I rings (Armstrong, Proc., 1890, 6, 227) in P-bromocamphor would be broken if the bromine were present in a methyl group-especially in view of the results obtained by Kipping on oxidising the rr-derivative. Until proof to the contrary be given, it may therefore be assumed that, of the three series of derivatives of camphor now known : the a- or homo-ketonic series is that in which hydrogen is displaced in the methylene group next the CO group ; the p- or hetero-ketonic series, that in which hydrogen is displaced in the methylene group next the ‘‘ mono-methylated ” carbon atom ; and the X-or meso-series, that in which hydrogen is displaced in one of the median methyl groups. There can be little doubt that the Reychler sulphonic acid belongs to the p- or hetero-ketonic series; were it an a-compound, it can scarcely be doubted that i t would yield some camphoric acid on oxidation.The manner in which the p- and rr-derivatives are formed merits special consideration. As we have previously remarked, the ketonic group is probably in all cases the “centre of attraction,” the point of departure of all changes. The formation of the homo-ketonic a-derivatives-alpha-1470 ARMSTRONG AND LOWRY : SULPHOKATION OF brornination, for example-may be pictured as taking place in the following manner : I n discussing the conversion of aa'-dibromocamphor into up-dibromo- camphor, and similar changes, under the influence of hydrogen bromide (Swarts), it is important to take into account the evidence recently brought forward by Forster favouring the conclusion that the carbon atoms in camphor are so situated that a trimethylene ring or triphane is easily formed by the union of the two carbon atoms on either side of the monornethylated carbon atom in camphor.The introduction of the bromine into the P-position, in fact, may be pictured as involving the following changes in the CH*CHMe*CO group: CH,*CMe*C(OH)Br -+ CMe< ?*OH CH CMe<X(?" + Br, -+ CHBr*CMe-CO + HBr. A similar explanation may be given of the formation of the P-sulphonic acid, The sulphonatiug agent is apparently a n acetyl- sulphuric acid whicb on combining with the ketonic group mould give rise to a compound containing the group CH,*CMe C( OAc)( 0 *SO,H), convertible by loss of sulphuric acid into the triphane derivative: By a reversible process, the latter might pass over into the &acid, becoming first CH(SO,H)*CMe*C(OAc), and then CH(SO,H)*CMe*CO.I n undergoing conversion into up-dibromocamphor, aa'-dibromo- camphor must obviously be reduced by the hydrogen bromide a t some stage in the process and tbe CBr, group converted into the CHBr group of a-bromocamphor ; the change may be pictured as taking place in the following manner : Y B r 2 + ~ ~ r --3 CBr, I YEr2 +H -+ yBrH+Br,+HEr. co C(0H)Br C(0H)Br Br co Whether this change occurs initally or whether-and to what extent-tribromination precedes reduction is open to question, but the latter is perhaps the more probable, inasmuch as camphor cannot be directly tribrominated in any complete manner although tribromo- camphor is readily formed as a bye-product on oxidising up-dibromo-CAMPHOR.III. OPTICAL INVERSION OF CAMPHOR. 1471 camphor with nitric acid, and a-chlorocamphor is convertible into a mixture of stereoisomeric pact'-chlorodibromocamphors. The process of rr-sulphonation must involve the opening of one of the rings a t an early stage. I f the rupture occur between the two methylated carbon atoms, everything is accounted for-including the optical inversion to which Kipping and Pope have directed attention as being so remarkable, and which, it is to be remembered, also takes place to a slight extent when bromocamphor is sulphonated (Kipping, Trans,, 1901, 79, 370). That such a rupture actually takes place, under certain conditions, follows necessarily from Bredt's proof (Annalen, 1901, 314, 369) that one of the products of the action of sulphuric acid on camphor is carvenone, which he regards as formed from dihydrocarvone : YHMe, Mey:CH, YH,mC--I-YH YH,*CH-$?H, CH,*CHMe* CO CH,*CHMe*CO Carvenone.Dihy drocarvone. The production of the latter compound is proof, not only that the ring is broken, but also that one of the methyls is attacked. This might well happen if, in the first instance, the ketonic group were t o combine with sulphuric acid, and then, by a reversal of the process, acid were to separate in such a manner that a n atom of hydrogen would be withdrawn from the contiguous methyl group, giving rise momentarily to a compound containing the group represented by the formula : 1 I CH;C*CH2 6H, I'U I .CRle-b*OH u Owing to the presence of two unsaturated carbon atoms, the molecule thus produced would be subjected to strains in two directions, both of which would tend-as shown by the arrows-to weaken the hold upon each other of the two methylated carbon atoms, and there- fore might well cause their separation, directly giving rise t o the dihydrocarvone postulated by Bredt. By combination with sulphuric acid, a compound might then be formed which, on being deprived of the elements of a molecule of water, would, by a reversal of the process, give rise t o camphorsulphonic acid. The process may be represented by the following scheme : H,C-YH--CH, Mey:CH, H,C'-CMe -CO CH,-CHMe-CO I MeQMe I 2 FH,-CH---~H, -+ f-1472 ARMSTRONG AND LOWRY : SULPHONATION OF CH2 PH Me$WH2*S0,H -+ H,C-CH-- I vH2* CH-YH, f- I MeF*CH2*S03H 1 .C.H,*CHMe* CO H,C-CMe-CO But an acid thus produced mould be optically active like camphor. To account for the racemisation, i t is necessary to postulate the occurrence of changes affecting both the asymmetric carbon atoms in camphor. The asymmetry of the carbon atom next the ketonic group might readily be reversed in sign by I‘ enolisation,” owing t o the presence of the hydrogen introduced in breaking the ring; but the “reversed ” compound could not take part in the re-formation of camphorsulphonic acid. On this account, and because the product of sulphonation is mainly racemic, i t is necessary t o suppose that a further change takes place involving the reversal of the asymmetry of the second carbon atom. This may be accounted for by supposing that, under the influence of the acid, dihydroeucarvone-or, more probably, the isodynamic dihydro- eucarvenol-is produced, and that equilibrium is established, not only between this compound and dihydrocarvone, but also with camphor, as shown in the following scheme : Camphor d - t 1.-+ f- - I @H /\ H27 QH2 H2C co \/ @HMe Me\/M6 y-0 SO,H Me\/Me c I1 C /\ 3 3 2 7 7H2 \/ H,C C*OH CiUe - ( d f I.) (d + I.) (Inactive.) Both the forms of dihydrocarvone required to give the two forms of camphor would then be present. I n justification of this argument, Butlerow’s experiments (Annulen, 1877, 189, 44) on the oxidation of isodibutylene may be quoted, in which i t was shown that under the influence of sulphuric acid i80- dibutylene is converted into an isomeride, an equilibrium being estab- lished between the two compounds, so that products of oxidation are obtained which are derived, not, merely from the hydrocarbon taken, but also from an isomeride.And not only was this the case, but evidence was also obtained of the presence of two alcohols in equilibrium with the hydrocarbons :CAMPHOR. III OPTICAL INVEBSION OF CAMPHOR. 1473 CH,\,CH, CH,\/CH, --+ ?*OH --+ g YH f- I .f- 3\/ 7% CH CH,*OH CH,. QH f- 7% -+ QH2 C Jle, CMe, CMe, CMe, Leading, as it does, to a highly racemised product, the sulphonation of camphor must therefore be regarded as a process involving a com- plex series of changes in which equilibrium is established between no less than three isomeric ketones, and the proportion of dihydroeucar- vone present must be the determining factor in regulating the extent to which racemisation takes place.It is of interest to note to how great an extent the presence of bromine in the a-position deter- mines the equilibrium in one direction, so that scarcely any racemisa- tion is effected when bromocamphor is sulphonated. The formation of acetyl-o-xylene (together with carvenone) by the action of sulphuric acid on camphor (Armstrong and Kipping) may almost be regarded as proof that the rupture of the median ring is accomplished through the intervention of the ketonic group. Whilst we did not think i t necessary t o postulate the formation of a direct linkage between the ketonic: carbon and a median methyl, such a linkage must evidently arise if the transference of a methyl group from the one position to the other is to be explained.The following scheme may serve in a measure to indicate the course of change : VOMe H2C!-CB-CEJ2 H,C-CH-OH, CH 1 I Mel*OH I H2Q /'\ 5!H2 H,C CMe(0H) H,C'-CMe-C*OH H,C-Chle-UMe(OH) \ / It is well known that by the action of '' dehydrating " agents on camphor, a variety of benzenes are formed (compare Armstrong and Miller, Ber., 1883,16,2255), and that when care ia taken to carry outthe decomposition at as low a temperature as possible, the products appear to be practically all C,, derivatives-of which four are formed: cymene, metacymene, 1 : 2 : 4-dimethylethylbenzene, and 1 : 2 : 3 : 5- tetramethjlbenzene ; higher and lower benzenes are only formed when the conditions are such as to favour the occurrence of secondary changes.It is therefore probable that the transference of methyl groups involved in the production of several of the hydrocarbons may be conditioned by reversible intramoEecuZar changes such as are con- templated above, rather than by a succession of analytic and synthetic operations of the type determined by aluminium chloride, f o r example, VOL. LXXXI. 5 G1474 SULPHONATION OF CAMPHOR. 111. The production of mstacymene by means of phosphorus pentasul- phide and of zinc chloride may be accounted for if it be supposed that a triphane ring is first formed by the interaction of the ketonic group and the (ortho) methyl group attached to the contiguous carbon atom ; and that this ring is subsequently broken in such a manner that methyl becomes attached to the carbon atom of the ketonic group, meta t o the propyl group formed by scission of the linkage across the hexa- phane system.This argument is equally applicable in explanation of the oxidation OF the ortho-methyl group which is involved in the formation of ketopiaic acid from chlorocamphane (turpentine hydri- chloride), and of camphoic acid from camphene. To explain the formation of tetramethylbenzene, one of the chief products of the action of iodine, and which is also formed by the action of k n c chloride and of phosphorus pentasulphide on camphor, it is necessary to suppose that both the meso-methyls may be brought into connection with the hexaphane system.Assuming that one of the methyls were tranbferred t o the ‘ I keto- position ” in the manner shown above, in discussing the formation of acetyl-o-xylene, a compound would be formed from which the ele- ments of a molecule of water might be withdrawn in two ways : either in such a way as to give rise to the formation of the group CH,:C from the median *C*OH group, or in such a way as to involve the coupling of the ketonic group with the P-carbon atom. If, in either case, the change were to be reversed, hgdroxy-compounds would be formed (either T‘ or p), which would give rise, if deprived of the elements of water, t o a (r’P)-tetr.aphane derivative, corresponding t o the pp-corn- pound formulated on page 1473. If the tetraphane ring thus formed were subsequently broken, so as t o Sever the connection between the median carbon atom of camphor and that which had previously been associated with it in the form of methyl, the methyl group would be transferred t o the P-position ; three methyl groups would then bo con- The production of benzenes from camphor in the manner contem- plated involves the withdrawal of hydrogen at some stage in the pro- cess ; it is unnecessary to discuss the manner in which this may take place, but it may be pointed out that, however carefully the operation be conducted, a large proportion of resinous matter is always formed, and it may be that the withdrawal of hydrogen is in some way con- nected with the formation of this; it is noteworthy that even zinc chloride gives rise to the production of a not inconsiderable amount of the saturated hydrocarbon, C,,H,,.Lastly, it is of interest to note, as a further illustration of the influ- ence of bromine as a depressant of activity, that bromocamphor does tiguous.ACTION OF NITRIC ACID ON BROMOPHENOLIC COMPOUNDS. 1475 not give rise to hydrocarbons under the influence of dehydrating agents. We are inciined to think that the views advanced in this communi- cation may be of some value in arriving at the synthesis of camphor and that the recognition of reversible changes as playing a part in the formation of camphor and terpene derivatives generally may be of importance. CHEMICAL DEPARTMENT, CITY AND GUILDS OF LONDON INSTITUTE, CENTRAL TECHNICAL COLLEGE.

ISSN:0368-1645    

DOI:10.1039/CT9028101469

出版商:RSC    

年代:1902

数据来源: RSC

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ACTION OF NITRIC ACID ON BROMOPHENOLIC COMPOUNDS. 1475 CXLV.-The Action of Nitric Acid on Bwmophenolic Compounds. By WILLIAM ROBERTSON, A.R.C.S. IN the course of the work on 2 : 6-dibromo-4-nitrosophenol (Forster and Robertson, Trans., 1901, 79, 686), attention was drawn to the simultaneous replacement of bromine by nitroxyl and oxidation of the nitroso-derivative to bromodinitrophenol by means of nitric acid. It seemed desirable t o determine, if possible, the conditions under which the bromine was liberated from benzenoid substances, as, although observations had been made, no extensive study of this subject had been undertaken. It is known that when tribromophenol is gently heated with nitric acid, the bromine atom in the para-position is first replaced and subsequently that in the ortho-position.If, how- ever, 2 : 6-dibromo-4-acetylnminophenol be treated with nitric acid, the operation must be carried out in an acetic acid solution and close to its freezing point, 2-bromo-6-nitro-4-acety~aminophenoZ being obtained, The presence of the acetylaniino-group in the para-position relatively to the hydroxyl causes the bromine to be very easily replaced. Armstrong and Lewis have shown (Proc., 1900, 16, 157) that benzoyl exerts a very remarkable inhibiting effect on certain reactions with phenols. The corresponding benzoylamino-compound was therefore prepared and nitrated, but the action of the nitric acid was found to be only very slightly slower than with the dibromoacetylaminophenol, 2 -bromo- 6-nitro-4-6enxoylccminopheno I being the resulting product.Auwers has pointed out (Ber., 1902, 35, 457) that 2 : 6-dibromo- 4-methylnitro-1-ketodihydrobenzene in contact with water passes into 3-bromo-5-nitro-p-cresol, that is, the nitro-group appears to wander 5 G 21476 ROBERTSON: THE ACTION OF into the meta-position, replacing the bromine atom. Now in the case of dibromoacetylaniinophenol, the replaceable bromine occupies the meta-position relatively to tke acetylamino-group, and it might be supposed, arguing from Auwers’ work, that the first substance formed would be a nitroketone which would immediately change into the benzenoid compound thus : Orton (this vol., 490, 806), in nitrating s-trihalogen anilines, found that bromine in the para-position, but never in the ortho-position, mas replaced by a nitro-group, and that the nitroarnine which could be isolated as an intermediate compound yields the same product on standing in an acetic acid solution containing a drop of sulphuric acid as was obtained in the direct nitration.As Orton points out, it is not necessarily correct to assume that the nitroamines occur as intermediate products, and, as in the case of phenols, there is no experimental evidence in favour of the view that nitrates are formed, the nitric acid would appear to act directly on the quinonoid tauto- meric form. If the hydrogen of the hydroxyl were replaced by other groupings, it might be supposed therefore that no liberation of bromine woulrl occur, or at all events that the action would be much slower. Accordingly, the acetyl derivatives of tribromophenol and 2 : 6-di- bromo-4-nitrophen01, 2 : 4 : 6-tribromoaniso1~1, 2 : 6-dibromo-4-nitro- anisole, and 2 : 6-dibromo-4-anisidine, and its acetyl and benzoyl deriva- tives were prepared, and it is of interest that in no case when the ex- periments were carried out on these substances under similar conditions was replacement of bromine by nitroxyl observed.Inasmuch as 2 : 3 : 4 : 6-tetrabromo-5-nitrobenzoic acid can be prepared by the nitration of the bromo-acid (Meyer and Sudborough, Ber., 1894, 27, 1584), the conclusion that a quinonoid form is essential for the liberation of bromine is strengthened. The investigation was accordingly extended to the hydroxybenzoic acids. When the dibromo- derivatives of salicylic and p-hydroxybenaoic acids are treated with nitric acid, the carboxyl group as well as a bromine atom is displaced, and in both cases 2-bromo-4 : 6-dinitrophenol results.When, however, tribromo-m-hydroxybenzoic acid is treated in the same way, two bromine atoms are replaced by the nitro-group, but the carboxyl group is not affected, and the resulting product in all probability is 2-6romo-NITRIC ACID ON BROMOPHENOLIC COMPOUNDS. 14'77 4 : 6-dinitro-3-hydroxybenxoic acid. The acetyl and methoxy-derivatives of the 0- andp-hgdroxy-acids behaved in the same way as the simple bromophenols. EXPERIMENTAL. p-Nitrosophenol, prepared according to the directions of Bridge (Annalen, 1893, 277, SS), was oxidised by nitric acid in the hope that the yield would be a much better one than is tbe case by the direct nitration of phenol. Baeyer and Caro used well cooled concentrated nitric acid to obtain the nitrophenol, but when the experiment mas conducted at 0' with nitric acid of sp. gr.1.42, I found 2 : 4-dinitro- phenol to be the product. The method finally employed wasas follows : 400 C.C. of dilute nitric acid (50 C.C. of acid of sp. gr. 1.42 to 150 C.C. of water) were heated to 40" and 50 grams of nitrosophenol gradually added in small portions. The reaction proceeded smoothly, and after all the nitrosophenol had been added, a dark red solution was formed which suddenly became a pasty mass of light brown needles. After one recrystallisation from water (with the aid of animal charcoal), the needles melted a t 114O and were almost white. The yield of recrystallised product was 60 per cent.of the phenol taken, the yield by direct nitration of phenol amounting to 15 per cent at most. Derivatives of 2 : 6- Dibromo-4-aminophenol, 2 : 6-Dib~omo-4-cicetylan~inophenoE.--Fifty grams of p-nitrophenol were dissolved in glacial acetic acid and two molecular proportions of bromine added to the cold solution. There is considerable develop- ment of heat, the temperature rising to 45-60', The whole was allowed to stand for 12 hours, poured into water, filtered, and washed. I n this way, a theoretical yield of 2: 6-dibromo-4-nitrophenol (m. p. 142') was obtained. The reduction of this compound to the corresponding amino-derivative was effected by tin and hydrochloric acid. The best yield is obtained by using only a very small quantity of hydrochloric acid, as in excess of that reagent the stannochloride of the base is insoluble.The mass became warm on covering the amine (m. p. 190') with acetic anhydride, solution occurred accompanied with a violet coloration (compare Meldola, Woolcott, and Wray, Trans., 1896, 69, 1324), and finally the whole solidified to a white paste. It may here be remarked that the violet colour, although noticeable in the large majority of cases, was not always observed. Meldola and his pupils ascribed the colour to an oxidising effect of acetyl peroxide; here, a t all events, i t would seem to be due to some impurity in the base. The product is sparingly soluble in hot water, but dissolves easily in alcohol, acetic acid, or alkali, and the needles melt a t 185-18691478 ROBERTSON: THE ACTION OF The crystals from acetic acid contain acetic acid of crystallisation and melt at 178-179". On exposure to the air, they effloresce and then melt at 185'.Holz (J. pr. Chem., 1886, [ii], 32, 68) states that the substance forms small, glistening plates melting a t 173-1 74", whereas Friedlander and Stange (Ber., 1893, 26, 2262) describe it as crys- tallising in needles soluble in alkali and melting a t 185' : 0.1751 gave 0.2140 AgBr. Br=52*01. C8€€,02NBr2 requires Br = 5 1 *78 per cent. Action of Nityic Acid.-The acetyl compound suspended i n glacial acetic acid and cooled to near the freezing point of the solution was treated with 13 mols. of nitric acid. Bromine wasimmediately liberated. The yellow product obtained on pouring the solution into ice water, after being washed and dried, was crystallised twice from methyl alcohol.The melting point of 6-bromo-2-nitro-4-acetylaminophenol is 230' : 0.1532 gave 12.8 C.C. nitrogen at 14' and 766 mm. 0.1316 ,, 0.0902 AgBr. Br=29-23. The substance is very soluble in the usual organic solvents. All attempts to hydrolyse the compound proved futile. 2 : 6-Dibrorno-4-be~zoyZarninophenol.-This compound was prepared from the corresponding aminophenol (Forster and Robertson, ZOC. tit.) in order to compare the influence of the benzoyl and acetyl radicles : N = 9.91. C8H70,N,Br requires N = 10.18. Br = 29-09 per cent. 0.1211 gave 0.1227 AgBr. C,,H,O,NBr, requires Br = 43 e l 3 per cent. It gives the nitro-derivative with nitric acid in precisely the same way as the acetylamino-compound, but the temperature required for the nitration is 18-20'.The product, 2-bromo-6-nitro-4-benxoyZamino- phenol, easily dissolves in organic solvents and crystallises in small, yellow needles from methyl alcohol. After several crystnllisations, it melts at 247' : Br = 43.12. 0.1341 gave 0.0729 AgBr. C,,H,O,N,Br requires Br = 23-74 per cent. 2 : 3 : 6-~~i6romo-4-cccetyZam~~op~e~oZ.--Eighty grams of dibromo- acetylaminophenol were dissolved in glacial acetic acid, and while the solution was still warm one molecular proportion of bromine was added. After standing for twelve hours, the red prisms which had deposited mere filtered off on the pump, washed, and dried. When dried, the crystals gradually became of a light brown colour and the mass weighed 77 grams.From the mother liquor, by addition of water, a yellow precipitate was obtained weighing 3 grams, which Br = 23-14,NITRIC ACID ON BROMOPHENOLIC COMPOUNDS. 147'3 consisted chiefly of bromoanil (m. p. 299-300O). The tribromoacetyl- aminophenol, after three recrystallisations from alcohol, formed white needles which melted a t 224' with decomposition : 0.1141 gave 0.1653 AgBr. Br=61*66. C8H,02NBr3 requires Br = 61 *85 per cent!. When nitric acid mas poured into an acetic acid solution of tri- bromoacetylaminophenol a t the ordinary temperature, only a tar, small in amount, was obtained. On heating, the only recognisable products were oxalic acid, dibromodinitromethane, and probably bromoanil. Action of Nitric Acid on the Acetyl Derivatives of 2 : 6-Dih1~orno-4-nit1*0- phenol and Tg-ibromophenoL-When nitric acid of sp.gr. 1.5 is poured on either of these acetyl compounds, bromine and nitrous fumes are liberated, but on dilution with water the original substance only is obtained, the action of the acid being apparently destructive. The melting point of tribromophenylacetate is 84", Schunck and March- lewski (Annalen, 1194, 278, 347) give 82". Anisole Derivatives, 2 : 6-~ibromo-4-nitroccnisole.-An attempt to prepare this compound from the corresponding silver phenate and metbyl iodide giving only a meagre yield, it was thought t h a t the yield might be improved by the employment of Lander's method of etherification (Trans., 1900, 77, 729). The dibrornonitrophenol was dissolved in absolute alcohol and the silver oxide and methyl iodide added in Lander's proportions.After heating for three hours, the filtered solution was poured into dilute alkali, filtered, and dried, In this way, a 60-65 per cent, yield was obtained, and the unaltered phenol mas recovered from the alkaline filtrate. Heating for four hours did not materially increase the yield. The white needles from alcohol melted at 123O ; Korner (Gaxxetta, 1874, 4, 390) gives 122.6". 2 : ~-Dibromo-4-ccnisidi.ne.-The reduction of the nitroanisole by t i n and hydrochloric acid is slow owing to t h e insolubility of the compound in the acid. The amine is very easily soluble in the usual organic solvents, and crystallises best from light petroleum in small, white, glistening leaflets melting at 66'.Stadel (Annalen, 1883, 217, 70) ob- tained this compound, but does not give its melting point : 0.1537 gave 0,2054 AgBr. C7H,0NBr, requires Br = 56-94 per cent. The acetyl derivative, prepared in the same way as the dibromo- acetylaminophenol, forms long, slender needles from methylated spirit, and melts at 206'. It is sparingly soluble in boiling water or potroleum, Br = 56.87.1480 ROBERTSON: THE ACTION OF moderately so in benzene, and easily so iu alcohol, methyl alcohol, ethyl acetate, acetic acid, or chloroform : 0,1860 gave 0.21 78 AgBr. C,H,O,NBr, requires Br = 49.53 per cent. The benzoyl derivative, prepared by means of the Schotten-Baumann reaction, crystallises from alcohol in needles which soften at 174" and melt a t 180". It is easily soluble in methyl alcohol, acetic acid, or alcohol, and moderately so in benzene, but almost insoluble in hot water : Br = 49.83.0,1553 gave 0.1524 AgBr. It is noteworthy that tribromoanisole and the above anisole derivatives do not liberate bromine when treated with nitric acid in the cold or at 30-403 Br = 41.76. C,,H1,O2Nl3r, requires Br = 41.99 per cent. 3 : 5-Bi6romosaZicyZic Acid. According to LeIlmann and Grothmann (Ber., 1884, 17, 2728), this acid can be most easily prepared by dissolving salicylic acid in glacial acetic acid in the cold and adding five atomic proportions of bromine. The liquid, after being allowed to stand for one hour, is poured into water and afterwards digested for some time with water to get rid of a volatile impurity. The product is finally converted into the barium salt, from which the pure acid is liberated.These direc- tions were carried out up t o the prolonged digestion with water, and a s the acid melted at 216" (compared with 221' for the pure acid) i t was regarded as comparatively pure. This, however, is by no means the case, as on attempting to prepare the acetyl derivative from the product melting at 216O, the substance obtained in a state of purity waa the cccetyl derivative of tribromophenol: it melted a t 84", and a mixture of it with a specimen of tribromophenyl acetate also melted at 84" ; further, it contained Br= 64.51 per cent. (calc. Br = 6 1-34 per cent.), was insoluble in caustic soda, and when hydro- lysed gave a product melting a t 94O, tribromophenol melting at I n order to ascertain the relative proportion of dibromosalicylic acid to tribromophenol, the crude brominated product (m. p.202') was submitted to steam distillation ; tribromophenol passed over slowly (m. p, 9 2 O ) , and the liquid remaining in the flask after filtration and cooling deposited white needles melting a t 220-221'. I n this experiment, 28 grams of tribromophenol and 14 grams of the dibromo- acid were obtained. Bromination in chloroform leads to the formation of 5-bromosalicylic 92-95".NITRIC ACID ON BROMOPHENOLIC COMPOUNDS. 14S1 acid (m. p. 1 6 4 O ) , and as, in a subsequent experiment conducted according to Lellmann and Grothmann’s directions. it was observed that gas was evolved clfter pouring the acetic acid solution into water, the excess of bromine was destroyed by the addition of sodium bisulphite, 5-bromosalicylic acid being again obtained, but no tribromo- phenol. Finally, the bromination was found to proceed easily in the presence of iodine.Ten grams of salicylic acid were dissolved in glacial acetic acid and 9.7 C.C. of bromine (2.5 mols.) and one gram of iodine were added while the solution was hot. After being allowed to stand for one hour, the solution was heated for a short time, and when cold poured into a concentrated solution of sodium bisulphite, when the acid separated out as a white, crystalline precipitate. This proved to be a mixture of the dibromo- with the mono-salicylic acid, the dibromo-compound largely predominating. The two compounds can, however, be easily separated by fractional crystallisation from glacial acetic acid in which the dibromo-acid is the less soluble.From 25 grams of salicylic acid, 40 grams of pure 3 : 5-dibromosalicylic acid mere obtained, together with 5 grams of an acid melting a t 163O, and therefore probably 5-bromosalicylic acid. This is a 75 per cent. yield compared with 30-35 per cent. which can be obtained by Lellmann and Grothmann’s method. The melting point of the acid is 231’ ; Lellmann and Grothmann found 223O (Zoc. cit.) : 0.2284 gave 0,2919 AgBr. A noteworthy point about this acid is that it decomposes carbonates with difficulty. Action of Nitric Acid.-On addition of dibromosalicylic acid to nitric acid of sp. gr. 1.42, there is no liberation of bromine in the cold, but on very gently warming, the mass goes into solution with evolution of gas and bromine.After heating for two minutes on a water-bath, the liquid was poured on t o ice and the yellow solid, after being collected and washed, crystallised from water. The resulting yellow needles melted at 117’ and a mixture of this substance with bromodinitro- phenol also melted at 1 1 7 O , thus identifying the product. The needles were recrystallised from alcohol and analysed : Br = 54-39. C7H,0,Br2 requires Br = 54.05 per cent. 0.2530 gave 0.1827 AgBr. Br = 30-73. C,H,O,N,Br requires Br = 30.41 per cent. I n this experiment, therefore, the carboxyl group in addition to a bromine atom has been replaced by the nitro-group. From 10 grams of dibromosalicylic acid, 7.5 grams of 6-bromo-2 : 4-dinitrophenol were obtained.Acet3l-3 : 5-dib?~on~osccZicyEic acid, prepared in the usual may, me1 ts1482 ROBERTSON: THE ACTlON OF at 156' and crystallises from dilute alcohol in needles or leaflets. It is sparingly soluble in water or light petroleum but easily so in the other solvents : 0.1820 gave 0*2035 AgBr. Br = 47.35. C,H,O,Br, requires Br = 47.34 per cent. Nitric acid of sp. gr. 1-42 to which a few drops of concentrated acid of sp. gr. 1.5 had been added liberated only a trace of bromine at 60'. Methyl dibromo-o-methoxybenzoate was prepared from dibromo- salicylic acid by Lander's method, alcohol again being used as solvent. It crystallises from petroleum in beautiful, long prisms which melt at 52' (compare Peratoner, Gaxxetta, 1886, 16,417). Dibromo-o-methoxy- benzoic acid, prepared from the ester, melts at 194" (Zoc.cit). Neither of these compounds liberates bromine when treated with nitric acid of sp. gr. 1.42 a t 60'. The acetyl derivative of 5-bromosalicylic acid does not seem to have been prepared hitherto; it melts at 168' when crystallised from alcohol : 0 2274 gave 0.1658 AgRr. Br= 31.03. C,H70,Br requires Br = 30.89 per cent. 3 : 5-Dibromo-khydroxybenxoic Acid. Hlasiwetz and Barth (Annalen, 1865, 134, 276) found that by the action of bromine water on p-hydroxpbenzoic acid they obtained tri- bromophenol. Beilstein makes the statement, evidently founded on this observation, that bromo-p-hydroxybenzoic acid cannot be obtained by direct bromination. Hahle (D.R.-P. 60637) obtained the mono- bromo-acid, but on attempting further bromination tribromophenol was the sole product.After the experience gained in the bromination of salicylic acid, it seemed advisable to re-examine the behaviour of p-hydr- oxybenzoic acid towards bromine. It was found that dibromo-p-hydr- oxybenzoic acid can be easily and readily obtained by carrying out the bromination iii acetic acid in the presence of iodine and pouring the product into sodium bisulphite solution in the same way as with sali- cylic acid. The yield is 80 per cent. of the theoretical, and the melting point 267-2668'. Methyl dibromo-p-methoxybenzoic acid was found to melt at 90-91'; Balbiano (Gaxxetta, 1883, 13, 66) records 91.5-92' (corr.) as the melting point. 0.2285 gave 0.2897 AgBr. On nitration, this acid yielded 9-bromo-4 : 6-dinitrophenol, just as in On analysis : Br = 53.95.C7H,0,Br2 requires Br = 54.05 per cent. the case of dibromosalicylic acid.NITRIC ACID ON BROMOPHENOLIC COMPOUNDS. 1483 The acetyl! derivative crystallises from alcohol in needles melting a t Nitric acid of sp. gr. 1.42 did not liberate bromine from it 207O. a t 60’ : 0,2527 gave 0.2810 AgBr. Br = 47.32. C9H604Br2 requires Br = 47.34 per cent. Balbiano (Gaxxetta, 1884, 14, 10) records that 2 : 6-dibromo-4-nitro- a.nisole results from the action of fuming nitric acid on dibromoanisic acid. I n this case, therefore, the carboxyl group but not the bromine atom has been replaced by the nitro-group. The ethyl ester was prepared by Fischer and Speier’s method (Ber., 1895, 28, 3252). It melts a t 99’ and crgstnilises in needles from alcohol : 0,2556 gave 0.2969 AgBr.Br = 49.43. CgH80,Br2 requires Br = 49.38 per cent. 3 -Bromo-4-rTLyd~~oxy6enzoic acid has been prepared by Hahle (Eoc. cit.), who does not give its melting point, and by Paal (Re?.., 1895,28,241 l), who obtained it as white needles melting at 148O, by the oxidation of the corresponding aldehyde. It may be obtained by brominating p-hydroxybenzoic acid in acetic acid solution in the absence of iodine, and purified by the method recommended by Pad, namely, crystallisa- tion from ethyl acetate and petroleum : 0.1575 gave 0.1377 AgBr. Br = 37.21. C7H,03Br requires Br = 36.87 per cent, The acetyZ derivative, melting at 155O, crgstallises from alcohol in needles : 0.1839 gave 0.1347 AgBr. Br = 31.17. C,H70,Br requires Br = 30.89 per cent.Bromination of m-Hgdroxybenxoic Acid. Ten grams of m-hydroxybenzoic acid mere dissolved in glacial acetic acid, gently warmed, and three molecular proportions of bromine added. After the expiration of one hour, the crystals ‘‘ A ” which had deposited were filtered off, and the mother liquor was evaporated, when an oil ‘‘ B,” which quickly solidified,. was obtained. By repeated fractional crystallisation from hot water, a product consisting of small tufts of glistening needles, which melt.ed a t 201--202O, was ultimately obtained. This proved on analysis to be a dibrorno-m-hydr- oxybenzoic acid crystallising with one mol. of water : Product (( B ” .-It was soon found that this was a mixture.1484 ACTION OF NITRIC ACID ON BROMOPHENOLIC COMPOUNDS.0.1282 lost 0.0076 H,O. H20= 5.93. 0.1983, dried for 4 hours a t l l O " , gave 0-2504 AgBr. C7H40,Br,,H20 requires H20 = 5.75 per cent. C7H40,Br2 requires Br = 54.05 per cent. As the determination of the constitution of this acid lay outside the scope of this inquiry, and the amount of m-hydroxybenzoic acid at my disposal was small, the further investigation of the substance was not attempted. A substance melting at 212' and consisting of hair-like needles was also obtained, Gut was too small in amount for examination. Product B " consisted mainly of tribromo-m-hydroxgbenzoic acid and melted a t 144O. T~ibromo-in-h~droxy6enxoic Acid.-Werner (Bzsll. Xoc. Chim., 1886, [ii], 46, 876) obtained this acid from m-hydroxybenzoic acid by using bromine water, but it was thought better to adopt the following method of preparation. Fivo grams of m-hydroxybenzoic acid were made into a paste with glacial acetic acid and three mols. of bromine were added. Heat was developed, and after allowing the mixture to stand for two hours water was added and the mass filtered off, washed, and dried on porous earthenware. On recrystallisation from water, the needles melted at 146--147O, which is the melting point recorded by Werner. Action of Nitric Acid.-The experiment on tribromo-m-hydroxy- benzoic acid was carried out precisely in the same way as with dibromo- salicylic acid. On pouring the product into water and filtering, a yellow solution was obtained which deposited a yellowish powder on concentration. Iii was recrystallised twice from water, in which it is freely soluble, and melted a t 217-218" with decomposition. The cal- cium salt is somewhat explosive. Determination of bromine in the substance shows that two atoms of that element have been replaced by nitroxyl, the resulting acid being a bromodinitro-m-hydroxybenzoic acid, and probably the 2-bromo-4 : 6-dinitro-acid : Br=53*74. I t is probably 4 : 6-dibromo-3-~ydroxybenxoic acid. 0.1928 gave 0.1192 AgBr. The acetyl and methoxy-derivatives of this acid were not prepared Br = 26.31. C7H,07N2Br requires Br = 26.06 per cent. owing to lack of material. In conclusion, the author wishes to record his indebtedness to Pro- fessors Tilden and Wynne for valuable suggestions and help given to him in the course of this inquiry. ROYAL COLLEGE OF SCIESCE, LONDON. SOUTH KENSINGTON, S.W.

ISSN:0368-1645    

DOI:10.1039/CT9028101475

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年代:1902

数据来源: RSC

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DERIVATIVES OF NORMAL CX LVI. - De riva t ives AND ISO-BUTYRYLPYRUVIC ACIDS. I485 of Normal and iso-Butyivylpyruvic Acids. By ARTHUR LAPWORTH and A. C. OSBORN HANN. THE compounds described in the present communication were prepared during the course of an investigation on theactionof sodium ethoxide and ethyl oxalate on the benzylidene derivatives of certain ketones, a reaction which, in the case of benzylidenemesityl oxide, appeared t o result in the formation of benzaldehyde and oxalyl derivatives, probably of acetone or the original rnesityl oxide. I n order t o obtain further evidence on the point, the interaction of ethyl oxalate and the benzylidene derivatives of some saturated ketones containing the acetyl group was studied, but the experiments did not lead t o the results which were anticipated.The formation of esters of acetylpyruvic acids by the condensation of ketones, containing the acetyl group, with ethyl oxalate has been studied by Claisen and his pupils in the case of acetone, acetophenone, mesityl oxide, &c. (Bey., 1888, 20, 2184, 3189 ; Annulen, 291, 132), and oxalyl derivatives of numerous ketones, esters, and nitriles have been isolated by other chemists. The free ay-diketonic acids obtainable from the ketones of lower molecular weight do not appear to have been prepared, a fact which is perhaps accounted for by the instability of the acids under the conditions which lead t o their formation from the esters, namely, alkaline hydrolysis, as this may result in condensation (Rer., 1890, 22, 3271) or the usual decompositions to which P-diketones are prone.On endeavouring to prepare the free acid from ethyl isobutyryl- pyruvate, me were much struck by the properties of a sparingly soluble compound which was obtained on acidifying the liquid which is formed when the ester is treated with strong potassium hydroxide under certain conditions. Analysis of the compound showed that it contained a small quantity of potassium, and i t was at first supposed to be a condensation product, but further investigation has shown t h a t it is an acid potassium salt containing 1 mol. of potassium isobutyryl- pyruvic acid and 3 mols. of the acid itself. Sodium hydroxide does not yield a similar compound. With normal butyrylpyruvic acid, a sparingly soluble potassium salt is also obtained, but this contains invariably a larger proportion of potassium than in the former instance, and we conclude that it is formed from 1 mol.of the normal salt and 2 mols. of the acid ; as in the first case, the corresponding sodium compound could not be obtained. The properties of these compounds recall the peculiarities of the quadroxalates, and their existence is interesting in the light of1486 LAPWORTH AND HA": DERIVATIVES OF the views expressed byAbegg and Bodlander (Zeit, acnovg. Chem., 1899, 20, 481) as.to the nature of such acid salts, The free acids, obtained by treating solutions of these salts with mineral acids, are very difficult to extract with ether unless the aqueous liquid is first treated with a very considerable proportion of strong sulphuric acid.They could only be isolated as oils, but had all the properties of ay-diketonic acids, whilst the two butyrylpyruvic esters doubtless exist as a mixture of the ketonic and enoEic modifi- cations. We have not yet been able to determine whether ethyl n-butyrylpyruvate is to be represented by the structure CH,E t *CO *CH,*CO*CO,E t, or the alternative one, CH;CO*CHEt~CO*CO,Et, although we believe the former to be the more probable, having regard to the exceptional readiness with which ketones containing the acetyl group afford oxalyl derivatives. EX P E R I M E NT AL. Ethyl isoButyryZpyruwccte, (CH,),CH*UO*CH2*CO*C02*C2H5. A mixture of 20 grams of methyl isopropyl ketone and 40 grams of ethyl oxalate is gradually added to a solution of 5.7 grams of sodium in 70 C.C.of anhydrous alcohol. absolute alcohol " is not sufficiently dry for use in this condensation. The liquid becomes bright yellow in a few moments, and a t the end of two o r three hours sets to a mass of crystals of the sodium derivative of ethyl isobutyryl- pyruvate. The crystals are removed by filtration, washed with a little alcohol, and recrystallised from a mixture of alcohol and ether. The free ester is easily obtained by shaking the sodium compound with dilute hydrochloric acid, and a further quantity may be recovered from the alcoholic mother liquors by shaking these with acidified copper acetate solution and decomposing the resulting crystalline copper derivative. The ester forms a fairly mobile liquid with a faint yellow colour, and may be purified by distillation in a vacuum. It boils with some decomposition a t 230-232' under atmospheric pressure. On analysis : Ordinary 0*3842 gave 0.6067 00, and 0.1954 H,O.C,H,,O, requires C = 58.1 ; H = 705 per cent. The substance shows no signs of crystallising at - 10'. Like other ay-diketonic esters, it dissolves readily in dilute alkalis, yielding solu- tions of a light yellow colour, and forms a number of sparingly soluble metallic derivatives. Dissolved in alcohol, it gives a brilliant, claret-coloured solution on addition of a drop of ferric chloride, It condenses readily with C = 58.3 ; H = 7.6.NORMAL AND ISO-BUTYRYLPYRUVIC ACIDS. 1487 hydrazines, affording sparingly soluble compounds which have not been closely examined. When a drop of piperidine is added to a mixture of the ester and a fatty aldehyde condensation ensues, the temperature rapidly rises, and water separates in a few minutes.The sodium derivative, CyH1304Na, separates from a mixture of alcohol and ether in fine needles. It is somewhat readily soluble in water, b u t less readily so in alcohol, ethyl acetate, acetone, or benzene, and is decomposed by acetic acid forming the free ester. Its solution in water affords characteristic precipitates with solutions of most metallic salts, The crystals probably belong t o the monoclinic system ; in plane polarised light, most of them show oblique extinction; in convergent polarised light, some are seen to have an optic axis emerging perpendicularly through the large faces, and the axial plane is identical with the plane of symmetry.On analysis : 0.1730 gave 0.0588 Nx2S0,. Na= 11.0. C,H,,O,Na requires Na = I1 *O per cent. The copper derivative, (C,H,,O,),Cu, may be obtained from the sodium compound or by shaking the free ester with a saturated solution of copper acetate. It separates from alcohol in bluish-green needles and is soluble in all the usual media with the exception of water. On analysis : Cu= 14.7. (C,H1304),Cu requires Cu = 14.5 per cent. 0.2524 gave 0.0468 CuO. The calcium derivative, (C,H,,O,),Ca, is precipitated in an amorphous form on mixing aqueous solutions of the sodium derivative and calcium chloride. It is practically insoluble in water, but dissolves very readily in ether, ethyl acetate, acetone, or hot alcohol. It separates from the last-named solvent in fine needles.On analysis : 0.3708 gave 0.1272 CaSO,. The barium compound, (CgH1,O,),Bri, closely resembles the calcium 0.2909 gave 0,1344 BaSO,. Ba= 27.2. The cobalt derivati~e,'(C~H~,O,)~Co, is highly characteristic and is formed as a very sparingly soluble yellow precipitate consisting usually of minute needles. It dissolves fairly readily in the usual organic media, and separates in well-formed needles from hot alcohol : Co= 14.1. (C,H130,),Co requires Go = 13.7 per cent. Ca= 10.0. (C9H1,0,),Ca requires Ca = 9.7 per cent. On analysis : derivative in appearance and solubility. (C,H,,O,),Ba requires Ba = 26.9 per cent. 0.3106 gave 0,0594 Co,O,.1488 LAPWORTH AND HA": DERIVATIVES OF The zinc, magnesium, nickel, lead, and aluminium compounds are all sparingly soluble in water, and for the most part crystalline.HydroZgsis.-When ethyl isobutyrylpyruvate is dissolved in excess of somewhat dilute alkali, it is slowly hydrolysed and in thecourse of a few hours addition of a mineral acid causes no precipitate, thus indicat- ing complete hydrolysis; the liquid almost invariably emits an odour of methyl isopropyl ketone, so that the acid formed evidently undergoes further decomposition to a small extent. Extraction of the acidified liquid with organic solvents does not afford any crystalline material, and only a small amount of acid residue is left on evaporating the extracting agent; this may be increased in amount, however, by adding a large excess of strong sulphuric acid to the well-cooled liquid before extraction.Finally, the following method of hydrolysis was employed. The dry sodium derivative of the ester, in amount not exceeding 5 grams, is placed in a mortar, and a 50 per cent. potassium hydroxide solution is added drop by drop while the whole is triturated, until the mixture forms a thick, opaque paste. It is then allowed to remain for not more than one minute (by which time the material has usually assumed the form of a nearly colourless, transparent liquid), diluted with water, and acidified with hydrochloric acid. The liquid deposits a mass of colourless crystals which may be purified by crystallisation from ethyl acetate or by solution in dilute potassium hydroxide and reprecipitation from the filtered liquid by means of hydrochloric acid. The substance melts sharply at 11 1-1 12' ; it is sparingly soluble in cold water, but dissolves readily in dilute alkalis or ammonia.Its aqueous solution is strongly acid and expels carbon dioxide from carbonates. When warmed with water, it is rapidly decomposed, an odour of methyl isopropyl ketone becomes perceptible, and oxalic acid may be detected in the liquid, Its liquid in dilute alkalis has a distinct yellow colour. The crystals of the substance are flat, rhomboidal plates j in con- vergent polarised light,an optic axis of a biaxial figure is seen to emerge obliquely through the large faces. 0.4476 gave 0 0594K,S04. K = 5.9. 0.2651 gave 0.0351 K,SO,. K = 5 9. Three specimens prepared on different occasions were analysed : 0.6482 ,, 0,0856 K,SO,. K = 5.8, C7H,0,K,(C7H,,04), requires K = 5.8 per cent.After admixture with dried and finely divided silica for the purpose 0.1496 gave 0.2771 CO, and 0.0801 H,O. of decomposing any potassium carbonate, (7-50.5 ; H=6.0. C7H,04K,(C7H,,04), requires C = 50.2 ; H = 5.8 per cent.NORMAL AND ISO-BUTPRYLPYKUVIC ACIDS. 1489 Attempts were made to determine the equivalent of the compound by titration against standard sodium hydroxide solution in presence of phenolphthalein; the end reaction, however, was so indefinite as t o render the result worthless. The aqueous solution of the substance gives, on addition of ferric chloride, a deep claret-coloured solution eFactly resembling that which the original ester affords. With copper sulphate, a bright green solution is formed. After neutralisation with cold ammonia, the solution gives no pre- cipitate with calcium chloride until it is boiled, when a copious deposit of calcium oxalate is produced. BenzyZidenemethyZ isoPropyE Xetone, (CH3),CH*GO*CH:CH*C6H5.- A mixture of methyl isopropyl ketone and benzaldehyde in molecular pro- portion, suspended in a 2 per cent.sodium hydroxide solution, is shaken at intervals during a week, and the product afterwards extracted with ether and isolated by fractional distillation under diminished pressure. It boiled with slight decomposition at 284-286' under atmospheric pressure, was an oil with a characteristic odour and showed no tendency t o crystallise at - 15'. On analysis : 0.2476 gave 0.7470 GO, and 0.1770 H20. C,,H,,O requires C = 82.7 ; H = S.0 per cent.The oxinze, C,,H,,ON, was prepared by warming the ketone with dilute alcoholic solution of hydroxylamine hydrochloride and caustic soda, and was precipitated on addition of water as a semi-crystallin'e mass which was purified by crystallisation from light petroleum, It dissolves somewhat readily in the ordinary media with the exception of water, and separates from light petroleum in curved, tooth-shaped crystals which melt at 131-132'. When warmed with dilute hydro- chloric acid, it is rapidly hydrolysed, affording the original benzyl- idene compound boiling at 274-276". C=82*3 ; H= 7.9. On analysis : 0.2268.gave 0.6355 GO, and 0.1690 H,O. C,,H,,ON requires C = 76.2 ; H = 7.9 per cent. The sernicarbazone, C,,H,,:N*NH= CO-NH,, dissolves readily in hot alcohol, acetone, ethyl acetate, benzene, or chloroform, but much less readily in the cold liquids, and is very sparingly soluble in light petrol- eum.It separates from a hot solution in ethyl acetate in the form of rectangular plates or prisms which melt and decompose at 166-167". The substance is easily hydrolysed by means of hot dilute hydrochloric acid. On analysis : C = 76.4 ; H = 8.2. 0.1 787 gave 0.4427 CO, and 0.1 182 H20. C = 67.5 ; H = 7.4. C,,H,70N, requires C = 67.6 ; H = 7.4 per cent. VOL. LXXXI. 5 H1490 DERIVATIVES OF NORMAL AND ISO-BUTYBYLPYRUVIC ACIDS. Eth yZ n-Buty rylpyruvate, CH,* C H, CH, COO CH, CO GO,* C,H, (?) . This substance was prepared from methyl n-propyl ketone by a process exactly similar to that previously employed in making the isomeric ester, but the condensation appears to proceed more slowly than in the latter instance.The ester forms a nearly colourl'ess liquid, which boils and decom- poses at 228-232' under ordinary pressure, and in general exhibits properties which resemble very closely those of the corresponding isobutyryl compound. On analysis : 0,2721 gave 0.5787 00, and 0.1876 H20. CgH1404 requires C = 58.1 ; H = 7-5 per cent. The sodium derivative, C,H,,O,Na, separates from alcohol in long, yellowish needles, and is somewhat readily soluble in water and in most of the ordinary media with the exception of light petroleum. On analysis : C = 58.0 ; H = 7.6. 0.2821 gave 0.0980 Na,S04. C,H,,O,Na requires Na = 11.0 per cent. The copper derivative, ( C,H,,O,),Cu, dissolves in the usual solvents with the exception of water, and forms small, greenish-blue, flattened prisms.Cu= 14.3. (C,HlsO,),Cu requires Cu = 14.5 per cent. Na= 11.3. A specimen crystallised from ethyl acetate was analysed : 0.2705 gave 0.0485 CuO. The calcium and barium derivatives crystallise in white needles from ethyl alcohol. The nickel compound forms pale green needles soluble in ethyl acetate or alcohol ; the cobalt derivative is yellow and crystallises from alcohol. The fmv-ous compound is bluish-purple. Hydrolysis.-When ethyl n-butyrylpyruvate is hydrolysed with strong potassium hydroxide in the mode previously described (p. 1488) and the alkaline liquid is strongly acidified, a sparingly soluble potassium salt is obtained which may be purified by crystallisation from cold ethyl acetate. Unlike the potassium salt of isobutyrylpyruvic acid, however, it forms asbestos-like needles ; these, in polarised light, are seen t o have oblique extinction, the angles varying widely accord- ing to the orientation of the crystals. Three distinct specimens were analysed : 0.7239 gave 0.1188 K,S04. K = 7-4. 0.3493 gave 0.0593 K,SO,. K = 7.6. C7H904K,(C7H,o04), requires K = 716 per cent. C7H,0,K,(CgH1004)1 requires K = 7.6 ; C = 49.2 j H = 5.6 per cent, 0.3647 ,, 0.0640 K2S0,. K = 7.8. 0.2052 gave 0.3676 CO, and 0.1034 H20. C=48.9 ; H=5.6.LAPWORTH AND HA" : MENTHYL PORMYLPHENYLACETATE. 1491 The aqueous solution of the compound, even after neutralisation with ammonia, affords no precipitate with calcium salts until the solution is boiled, when calciunz oxalate is precipitated. On addition of p-nitrophenylhydrazine acetate, a light yellow, microcrystalline precipitate is produced. In general, the chemical properties of this salt closely resemble those of acid potassium isobutyrylpyruvate. CLIEAIICAL DEPARTMENT, T 11 E G 0 LD s M I TH S' INS TIT U T E , NEW CROSS, S.E.

ISSN:0368-1645    

DOI:10.1039/CT9028101485

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

LAPWORTH AND HA" : MENTHYL PORMYLPHENYLACETATE. l.kc)I CXLVII.-Opticakly Active Esters of ,&Ketonic and &Aldehydic Acids. Part I. Menthy1 Formyl- phe rLy lacetate. By ARTHUR LAPWORTH and A. C. OSBORN HANN. IT is well known that the desmotropic forms of such substances as P-diketones and nitroparaffins differ markedly in many physical properties, such as density, refractive, absorptive, and dispersive power, and magnetic rotation, and that by means of these properties it is frequently possible to determine to which of two possible forms a compound may be referred under given conditions, and, in many cases, to follow the change of one form into another. In these cases, however, it is not easy to follow the changes rapidly in dilute solution. When the compounds themselves are optically active, however, observations on dilute solutions may be very rapidly made, and, as Lowry has shown (Trans., 1899, 75, 2-24>, may somebimes afford an accurate method of estimating the relative amounts of the two forms present at any time.In spite of the value which LOWrfS method of investigation by the observation of mutarotation may certainly possess, as shown by his own experiments on nitro- and 7r-bromonitro-camphor, and by those of Forster on nitrocamphane (Trans., 1900, 77, 260) and benzoyl- camphor (Trans., 1901, 79, 987), the principle has not yet been widely applied, the reason being, no doubt, that the number of active labile compounds of the kind which may be prepared i n a perfectly straightforward way is limited. I n order that the method may be employed to the greatest advantage, it is, of course, necessary that both desmotropic forms should be isolable.Nevertheless, even when only one of the two forms can be isolated in 5 H 21492 LAPWORTH AND HANN: OPTICALLY ACTIVE ESTERS OF the pure state, but the other exists in solution and has a different rotatory pgwer, as in the case of nitrocamyhor, mutarotation may be observable and the effect of agents on the velocity of change studied with advantage, especially since it is clear that when the two forms exist in equilibrium in solution a trace of an agent which affects the velocity of the change in one direction should affect that of the reverse change in a similar manner. Some of the most interesting and most debated cases of tauto- merism exist among the esters of P-ketonic and P-aldehydic acids, such as acetoacetic, formylphenylacetic, and acetoneoxalic acids, and it occurred to us that among the esters formed from these and active alcohols of high molecular weight, one or both of the two forms might be crystalline, and therefore capable of complete purification ; moreover, it seemed that by observations of the mutarotation, the question of the nature of the agents which accelerate or retard the change might be easily investigated.It might appear, at first sight, very improbable that she two forms of such esters would differ sufficiently in rotatory power, as the position in the molecule at which the desmotropic change occurs is somewhat remote from the centre of asymmetry. Nevertheless, the well-known large divergencies which exist between the rotatory powers as calculated by Guye’s method and those actually observed, as well as the very marked effect which is produced on the rotatory power of many compounds by varying the concentration and solvent, made i t seem quite possible that the differences between the properties of the two forms might in some cases be sufficiently large for the purpose.The first optically active ester of the type which we succeeded in preparing was menthyl formylphenylacetate ; the same compound has been independently prepared by Cohen and Briggs (Proc., 1902, 18, 172), and for the same purpose, and the results of these workers serve in the main to confirm our own. The corresponding ethyl ester was prepared by Wislicenus (Be?., 1895, 28, 767; 1896, 28, 742; Amnden, 1896, 291, 147; 1900, 312, 34) by the action of metallic sodium on a mixture of ethyl phenylacetate and ethyl formate, and we have found that a similar process, in which the corresponding menthyl esters are used, affords a fairly good yield of menthyl formylphenyl- acetate.The ethyl ester appears to be capable of existing in two rnodifica- tions. One of these is oily at the ordinary temperature and generally exhibits the properties of a true hydroxymethylene or enolic com- pound, both in its chemical and in its physical characters; thus, its solutions are rapidly coloured violet by ferric chloride, it dissolves readily in alkalis, and gives a copper derivative at once when its alcoholic solution is treated with copper acetate solution ; its specific,@-KETONIC AND @-ALDEEYDIC ACIDS.PART I. 1493 refractive power (Briihl, AnnuZen, 1896, 291, 217) and its absorptive power with regard to rapidly oscillating electrical vibrations (Wis- licenus, AmnaZen, 1900, 312, 32), are also i n agreement with the formula OH*C:CPh*CO,Et. The second modification has the chemical and physical characters of an aldehydic acid of the formula CHO*CHPh*CO,Et, The two forms me produced when solutions of the sodium derivative are acidified ; precipitation by carbon dioxide usually leads t o the production of the enolic form, whilst strong mineral acids in excess produce the aldehydic modification. The two forms are found t o be interconvertible, both at high and at the ordinary temperatures, and also in solution.It was found, moreover, that there are two stereoisomeric forms of the enolic modification, and isomeric copper and benzoyl derivatives were prepared. I n the case of the menthyl ester we have not been able to detect any tendency to persist in the ketonic form. Under all conditions in which Wislicenus found that the oily ethyl ester is produced, me have invariably obtained one and the same compound, and this we believe t o be the aldehydic form of the ester for the reasons stated on p. 1495. On the other hand, we have indications that equilibrium between the two forms is attained extremely readily in alcohol, and the importance of the non-production of a coloration with ferric chloride in benzene or chloroform solution may perhaps be over-estimated, as ethyl aceto- acetate or phenol gives only a faint coloration under these conditions.Further, we have found that, unlike the aldehydic ethyl eeter, the substance reacts rapidly with cold phenylcarbimide, interaction being complete in less than three days. From the description given by Wislicenus of the properties of the two ethyl esters, we are led t o think that the rapidity of change of the aldehydic into the enolic form and vice uersd mmt be far greater in the case of the menthyl ester, a difference which is very difficult to understand. We have also failed t o observe any indication of stereoisomerism in the metallic derivatives of the menthyl ester, Satisfactory evidence that we had been dealing with the menthyl ester of formylphenylacetic acid was afforded by the fact that when the substance is warmed with solutions of phenylhydrazine i t afforded diphenylpyrazolone, which is aIso obtained when Wislicenus' ethyl ester is treated in a similar way.With regard to the point which is held to be of the greatest importance in this investigation, namely, that of the mutarotation, the results were very disappointing. I n the first place, the amount of the mutarotation is very small, and this is the case in chloroform. I n the cases of oxygenated solvents such as alcohol, acetone, or ethyl acetate,1494 LAPWOR'I'H AND HA" : OPTICALLY ACTIVE ESTERS OF little or no mutarotation could be observed, and w0 believe this indicates that equilibrium between the two forms is attained too rapidly for observation, although it is impossible to decide this point satisfactorily.Moreover, the mutarotation in chloroform was so small that we do not feel justified in attaching any importance to the results of the experiments which were made on the influence of agents on the change, and i t may merely be stated that acceleration appeared to be caused both by acids and by bases. EX PER I M E N TA L. heparation of MenthyE Fo~rnplphenylacetate, CH 0 CH (C,H,)*CO,*C, -The rnenthyl phenylacetate required for these experiments was made by heating a mixture of 50 grams each of phenylacetic acid and menthol and 5 C.C. of sulphuric acid on the water-bath for six hours, dissolving the product in ether, washing repeatedly with sodium carbonate, drying with potassium carbonate, and distilling in a vacuum.The fraction employed boiled at 210-215Ounder 34 mm, pressure, had a sp. gr. 0.99, and a rotation [.ID - 68.15'at 16*5', and was found to be pure enough for the purpose for which it was required. I n the first attelhpt to convert it into the hydroxymethylene deriva- tive, sodium and amyl formate in absolute ethereal solution were used. The product appeared t o consist of a mixture of the amyl and menthyl esters and did not crystallise. Menthyl formate was therefore pre- pared ; i t boiled at 215--217' under atmospheric pressure. The following process was found to afford the best yield of the desired product. Sodium (2.3 grams) in thin shavings was placed with 200 C.C. of dry ether in a dry flask cooled by R stream of water. A mixture of 30 grams of menthyl phenylacetate aad 20 grams of menthyl formate was then added in small quantities at a time ; the sodium dissolved fairly readily and the liquid acquired an orange-yellow colour.After the operation was completed, the whole was allowed to remain for several hours, when it was poured into about 500 C.C. of cold water and well shaken with it. The light yellow, aqueous layer was then run off, extracted twice with pure ether, and finally freed from the ether which remained dissolved by means of a stream of air. On adding a few drops of dilute acetic acid, an immediate precipitation of an oil occurred ; -on stirring, this rapidly became converted into a white, pulverulent solid, and the addition of acid was then proceeded with. The product was col- lected on a filter, allowed to dry in the air, and crystallised from hot light petroleum, from which i t separated at once in a nearly pure form.On analysis:@-KETONIC AND &ALDEHYDIC ACIDS. PART I. 1495 0.2773 gave 0.7680 CO, and 0.21 16 H,O. C,,H,,O, requires C = 75.7 ; H = 8.6 per cent. Menthyl formylphenylacetate is readily soluble in almost all the usual organic media ; it dissolves readily also in hot light petroleum and separates on cooling in the form of magnificent, transparent pyramids or prisms, which are sometimes nearly a centimetre in thickness. During the crystallisation, flashes of light are usually observable, even in daylight ; this is the result of the property of tribo- luminescence, which the compound possesses in a remarkable degree, and appears to be caused by the cracking of the crystals owing to the change of temperature; the phenomenon is rendered more obvious by warming the vessel to which the crystals are adhering.The crystals lose some of their transparency when kept, sometimes slowly, at other times rapidly, and it is interesting to note that the power to exhibit triboluminescence diminishes with the transparency. The crystals are tetragonal prisms and shorn the forms (110) and (101). Tbey are frequently elongated in the direction of the c-axis. The double refraction is strong and positive in sign. The compound melts quite sharply at 82--83* and exhibits very little tendency to persist in the liquid condition, even after it has been kept in the fused state for more than an hour ; after solidification, it melts a t the same temperature as a t first.It seems likely, therefore, either that the tendency for the compound to become converted into the tautomeric form is slight, or that the change occurs with great rapidity; the latter view appears to us to be the more probable. When the solid is dissolved in benzene, chloroform, or light petroleum and a drop of an ethereal solution of ferric chloride is added, no coloration is developed at first. On standing, however, the liquid slowly becomes a faint reddish-violet, a change which is brought about rapidly by heating the solution to its boiling point. Again, if the solution in benzene is boiled for a few minutes and then cooled before the ferric chloride is added, a faint coloration is observable as soon as the reagent is added.A much more striking effect is produced if a trace of a base such as pyridine is introduced before or after the addition of the ferric chloride, when a deep violet coloration is at once developed. The development of the colour in alcoholic solution is much more rapid. If some of the powdered substance is placed in a test-tube, dissolved in alcohol, and at once treated with ferric chloride, a reddish-violet coloration is produced, and the intensity of this increases in a few seconds to a maximum. If an alcoholic solution which has been kept for some minutes or has been previously boiled and cooled is used, the maximum coloration appears to be developed instantaneously. These facts, as well as the circumstance that the solid and more stable form of the corresponding ethyl ester has the C = 75.5 ; H = 8.5.1496 LAPWORTH AND HANN: OPTICALLY ACTIVE ESTRRS OF aldehydic constitution, lead us t o believe that, in the present case, the solid is the aldehydic form of the ester.We have made many attempts to obtain a second form of the ester, but without success, By adding a solution oE the sodium derivative of the ethyl ester to excess of acid, an oily modification may be isolated, but under similar conditiohs we have always obtained the solid form of the menthyl ester; it is true that, for tl few moments after precipitation, the material forms an oil, but it invariably solidifies within twenty seconds, unless the sodium derivative has been pre- pared by using alcoholic sodium ethoxide ; i n this case, however, it is largely the presence of alcohol as an impurity which accounts for the smaller tendency to solidify, as may be shown by adding a little alcohol to water containing a small quantity of the finely-powdered solid in suspension, when the compound sometimes becomes oily, but solidifies once more if washed with water two or three times.There is, moreover, no reason t o suppose that the oily character which the material sometimes assumes under such conditions is connected with conversion into another form. In order to determine whether the compound exhibited mutarotation, which would serve to indicate a tendency t o undergo change into i t s desmotropic form, its rotatory power in various solvents was measured immediately after solution, and again after the solutions had been kept for various periods.In 2 per cent. solution in absolute alcohol, i t had [a], -64.9", and no alteration was observed after two days. To hasten any very slow change which might have been going on, a trace of piperidine was added, when the rotation fell t o - 63.9' immed ately and did not alter appreciably with time, so that the effect was probably not due to mutarotation at all. In chloroform solution (2 per cent.), the initial specific rotation mas [a], - '74.6' and fell slightly after the lapse of some days t o -71.3". Experiments were also made with solutions in benzene and petroleum, and in both cases a very slight fall of rotation with time occurred. I n no case, however, was the fall sufficiently great to render it likely that we should obtain any really useful results by studying the effect of agents on the change, and although several experiments were made Ghich appeared to indicate that both acids and bases accelerate the change, we do not feel justified in placing any reliance on them.The sodium derivative, ONa*CH:CPh*C0,*CloH19.-The ester is rapidly dissolved by alkali hydroxides with the formation of an opal- escent liquid, from which the ester is reprecipitated on addition of acetic acid. If the alkaline solution is too concentrated, much hydr- olysis occurs, and menthol is formed in considerable amount. How- ever, it is possible t o precipitate the sodium derivative of the ester from its aqueous solution by the addition of strong, aqueous, ice-cold&KETONIC AND P-ALDEHYDIC ACIDS.PART I. 1497 sodium hydroxide, when it appears in the form of thin plates with a pearly lustre, and may be crystallised from a mixture of benzene and absolute alcohol, It may also be obtained by adding sodium in the form of thin sheets or wire t o an ethereal solution of the ester. On analysis : 0.4168 gave 0.880 Na,SO,. C,,H,,O, Na requires Na = 7-1 per cent. The copper derivative, Cu(O*CH:CPh~CO,*C,oH,,),.-This is formed when a solution of copper acetate in water is added to a dilute alcoholic solution of the ester, and is precipitated in the form of a green oil which slowly solidifies, It is readily soluble in light petroleum, benz- ene, carbon disulphide, or ethyl acetate, separating from these on evaporation as a gum; i t is less readily soluble in methyl or ethyl alcohol, and crystallises from the former in green needles or prisms which melt and decompose at 92-95'.When the crystals are ex- amined in polarised light, they show varying angles of extinction; their double refraction is weak. Na= 6.8. On analysis : 1.9701 gave 0.2410 CuO. Cu= 9.7. (C,,H,,O,),Cu requires Cu = 9-4 per cent. The acetyl derivative, OAc*CH:CPh~CO,*C,,H,,, made by warming the ester with pure acetyl chloride on the water-bath for a short time, crystallised slowly from dry ether ;' these crystals were freed from adherent oily matter by being spread on porous earthenware and recrystallised from methyl alcohol. On analysis : 0.2122 gave 0.5687 CO, and 0,1591 H,O. C = 73.1 ; H = S.3. C,,H,,O, requires C = 73.2 ; H = 8.1 per cent. The compound is readily soluble in most of the usual organic media with the exception of light petroleum, in which it is rather more sparingly dissolved.It separates from methyl alcohol in fine needles melting at 51-52'; it solidifies very slowly on cooling to a mass of long needles. The crystals, in polarised light, show straight extinction ; the double refraction is strong, and the directions of greatest elasticity and length are coincident. The compound is insoluble in dilute alkalis and is slowly hydrolysed by these on boiling; when i t is heated with strong sulphuric acid, the odours of acetic acid and menthene are given o f f . The tenxoyl derivative, OBz*CH:CPh*C0,-ClOHl9, is precipitated as a n oil when the aqueous solution of the sodium derivative of the ester is shaken with benzoyl chloride.It showed no tendency to solidify, even when left for several weeks or when distilled in a vacuum, and then differs from the corresponding ethyl ester, which solidifies when1498 LAPWOltTH AND HA" : MENTHYL FORMYLPHENYLACETATE. subjected to this treatment. It gave the following results on analysis : 0.3132 gave 0.8794 CO, and 0.2161 H,O. The phenylcarbamate, NHPh*CO*O*CH:CPh*CO,~C,,H,,.-When phenylcxrbimide is added to the finely powdered ester, no noticeable development of heat occurs ; the solid slowly dissolves, and in a few hours a clear liquid is obtained if excess of the reagent is employed. If molecular proportions of the two materials are used, the whole finally sets to a semi-solid mass, which may be washed with a little light petroleum, spread on porous earthenware, and finally crystallised several times from ethyl acetate.C = 76.5 ; H = 7.6. C26H3004 requires C = 76.S ; H = 7.4 per cent. On analysis : 0.2825 gave 0.7658 CO, and 0.1872 H,O. C,,H,,O,N requires C = 74.1 ; H = 7.4 per cent. The compound is sparingly soluble in chloroform, carbon tetra- chloride, benzene, or light petroleum, and somewhat sparingly so in methyl alcohol; i t dissolves readily, however, in ethyl acetate or warm ethyl alcohol. It crystallises fairly well from ethyl acetate and melts somewhat indefinitely at 235-237O when slowly heated. The crystals are small needles and in polarised light show straight extinction; the directions of greatest elasticity and length are a t right angles. When melted on a glass slip beneath a cover glass, i t solidifies completely to masses of long needles making up broad patches with aggregate extinction.Action of Hydroxylamine and of Hydraxine on Menthyl _Formy@henyt- acetate.-Numerous attempts to prepare the pure oxime were made. When an alcoholic solution of the ester is mixed with a strong aqueous solution of bydroxylamine, or when aqueous solutions of the sodium derivative of the ester and hydroxylamine hydrochloride are mixed, a viscid, colourless oil separates a t once; this oil has the general properties of an oxime, being somewhat soluble both in dilute acid and dilute alkali, but all attempts to obtain it in a crystalline fqrm were unsuccessful. Efforts to prepare crystalline hydrazones of the ester were equally unsuccessful ; when solutions of the ester in either alcohol or acetic acid were mixed with the acetate of hgdrazine, phenylhydrazine, or p-nitrophenylhydrazine, or with t h e two latter in the free state, no precipitation occurred even when the mixtures mere allowed to remain for some weeks. If the solutions containing phenyl- hydrszine were heated, a crystalline material separated which was collected ; it crystallised from acetic acid in small plates and melted at 196-198'. On heating the compound with strong alkalis or acids, no menthol C = 73.9 ; H = 7.4.LAPWORTH AND HAKN : MENTEIYL ACETOACETATE. 1409 or menthene was liberated, and further investigation proved that the substance was identical with the diphecylpprazolone which had been previously obtained by -similar treatment of ethyl formyl- phen y lace ta te. Our thanks are due to the Research Fund Committee of the Chemical Society for a grant defraying most of the expense of this work. CHEMICAL DEPARTMENT, THE GOLDSMITHS’ INSTITUTE, NEW CKOSS, S.E.

ISSN:0368-1645    

DOI:10.1039/CT9028101491

出版商:RSC    

年代:1902

数据来源: RSC