摘要:

ACTION OF ACIDIC OXIDES ON SALTS OF HYDROXY-ACIDS. 1451 XC1V.-The Actioiz of certain Aciclic Oxides on Salts of Hydroxy-acids. 111. By GEORGE G. HENDERSON, D.Sc., M.A., and JOHN M. BARR. COMPOUNDS formed by the interaction of antimonions oxide with potassium hydrogen mucate and potassium hydrogen malate respec- tively were described in a former communication to the Society (Trans., 1895, 67, 1030), but, a,s the analysis of these substances showed that their composition was somewhat complex, it appeared1452 HEXDELSON AND BXRR: THE ACTION O F desirable to prepaye other similar salts in order to confirm the for- mulae assigned to the first. This has now been done, and the action of arsenious oxide on primary mucates and malates has also been examined, with the results detailed below.In addition, the action of antimonious and arsenious oxides on salts of certain hydroxy- benzoic acids has been studied, and the investigation of the be- haviour of those acidic oxides towards salts of certain typical hydroxy-acids has thus been completed. Our experiments were then extended to other acidic oxides, and we selected in the first place molybdenum and tungsten trioxides, and in the second place silicon and titanium dioxides. Compounds of the two former oxides with primary tartrates are described below ; titanium dioxide appears to form compounds which are a t present under investigation ; silicon dioxide, on the other hand, apparently does not react directly with primary tartrates. Antimonious Oxide and Primary Malates. Amnlonircm antimoitiomalate was prepared and purified in the same way as the potassium salt already described (Zoc.cit.), observation of the same precautions being necessary in order to obtain a satisfactory yield, €or in this case also the action of the oxide on the malate proceeded very slowly, and prolonged heating of the solution was essential. The new salt. was obtained in large, colourless crystals, which are easily soluble in water and fairly soluble in dilute alcohol ; it decomposes when heated to about 115O, giving off ammonia, and leaving a brown residue which is insoluble in water. The salt also decomposes when an aqueous solution is boiled for a short time, unless excess of antinionious oxide is present. The addition of caustic alkalis or mineral acids to the solution causes immediate de- composition.Analysis of the salt, dried in air, gave the following figures. Calculated for 2Sb20 (C, H,O;NH,) ,:Sb,O (C4H60,) 4,20H20. Found. Sb .......... 25.53 25-1 7 HzO ......... 12.87 12.55 The water was determined in a vacuum over sulphuric acid. The composition of the potassium salt agrees better with a formula similar t o the one given above than with that previously assigned to it. Found, Sb = 25-69, K = 11.42, H,O == 4-52; calculated foP 2Sb~O(C~H~O~K)~,Sb~O(C~H~0~)~,7H~0. S b = 85-76 ; I( = 11.17 ; H,O = 4.51. sent them as double salts. from them by any of the methods emploged. It will be seen that the formulae assigned to these compounds repre- No simpler compounds could be obtainedCERTAIN ACIDIC OXIDES ON SALTS OF HYDROXY-ACIDS.1453 Antimonious oxide dissolves slowly in a boiling solution of sodium hydrogen malate, and after removal of nnaltered malate by crystalli- sation, the addition of alcohol to the solution causes the precipita- tion of a thick, coloui*less syrup, which, when tested qualitatively, was found to contain antimony in abundance, sodium, and organic matter, and which, no doubt, consisted principally of sodium anti- moniomalate. We did not succeed, however, in obtaining the pure salt in a crystalline condition, and the syrup underwent spontaneous decomposition on standing. Arsenious Oxide and Primasy Malates. A8 formerly stated, although arseuious oxide dissolves freely in a solution of potassium hydrogen ma.late, attempts to obtain a com- pound corresponding to the antimony salt were unsuccessful.Ex- periments with the primary sodium and ammonium salts likewise failed, although, in the case of the latter, the existence of a compound was at least indicated. On boiling the oxide in a solution of the primary ammonium salt for some time, allowing excess of oxidc to crystallise out, and then adding alcohol,. crystals separated which were found to contain 12-13 per centt. of arsenic. They were fairly soluble in cold water, but always decomposed when subjected to purification. A salt corresponding in composition to the antimony compound would contain 17.37 per cent. of arsenic, and the crystals obtained might be a mixture of this with a little unaltered malatle. The preparation of a barium salt was also tried, but without success.A?~tiinoiiiot~s Ozide and Prirnavy Mucates. Ananzoniztrn antimowiomucnte, like the potassium salt (Eoc. cit.), was obtained by boiling antimonious oxide for several days with a soln- tion of the primary mucate. On concentrating the solution, a powder separated, which, after recrystallisation fi-om hot water and drying in the air, gave the following figures on analysis. Calculated for F O U I ~ . 2SbO (NH,) CsHsOs, (NH.JC6H,Os,’7LT20. Sb .......... 22.18 22-26 H,O ......... 11.50 11-70 From these figures the compound would appear to be a double salt, but whether this be so 01- not, it behaves exactly like the potassium compound when it is reci.gstallised several times, namely, its com- position changes, and the ,pimple salt is finally obtained. This is seen by the following analysis of the salt prepared by recrystallising the original substaiice until the percentage of antimony remained constant.1454 HENDERSON AND BARR: THE ACTION OF Calculated for Found.SbO(NH4)C4H,08,3 H,O. Sb.. ...... 28.64 28.82 EItO ...... 12-24 12-98 The water was determined in a vacuum over sulphuric acid. The salt is thus obtained in the form of a white, finely crystalline powder, only sparingly soluble in cold, but fairly in hot water. 111 its other properties it closely resembles the potassium salt. In preparing sodiicnz nntimoniomucate, SbONaC4H808,3H,0, a similar process was employed, but there was this difference, that the crude product, when recrystallised twice, had a composition agreeing with that calculated for the simple salt, there being no appearance of the formation of ail intermediate substance, Found.Calculated. Sb 28.13 28.50 H,O ........... 12-77 12.82 The sodium salt is also a crystalline powder, rather more solable in water than the potassium and ammonium salts, but very like them in other respects, On the addition of barium acetate to a solut'ion of the sodium salt, a white precipitate forms after a short time. The powder, washed with water and dried in air, xas found to contain 24 per cent. of antimony, but decomposed when it was heated w i t h water with the object of purifying it by 1-ecrjstallieation. A barium salt corre- sponding to the sodium salt woiiltl contain 25 per cent. of antimony. ............ Arsenious Ozide and P&n ary Mucates. As already stated, the arseniomucate of potassium, owing to its instability, could not be obtained in a state of purity.The same results followed when the preparation of sodium and ammonium salts was tried, for though the oxide dissolved freely in solutions of both salts, and gave crystalline products containing considerable quantities of arsenic, the instability of these was such t,hat no definite com- pounds could be prepared free from adrnixtum with unaltered rnucates . Antim oiiious and A?.seruioibs Oxides u i d JIami?elntes. I n experiments on the action of these oxides on alkali lactatep, thick sjrups were obtained containing some antimony or arsenic respectively, but they could not be further purified, and wlieii a solu- tion of barium lactate was used the results were practically the same.Hence, instead of lactates, we took the alkali salts of mandelic (phenyl-lactic) acid, which crystallise well, in the hope of obtaiiiingCERTAIN ACIDIC OXIDES ON SALTS OF HYDROXY-ACIDS. 1455 crystalline products, but it was found that antimonious oxide was almost insoluble in solutions of these salts, and that, although arsenious oxide dissolved to some extent, apparently it formed no compounds with the mandelates. Antirnonious and Arsenious Orides and Salicylates and Gallates. Having found that antimonious and arsenious oxides react with the salts O F various alcohol acids to form definite compounds, we proceeded to examine the behavioiir of these oxides towards bydroxy- benzoic acids, selecting in the first instance salicylic and gallic acids.The oxides were added to boiling solutions of alkali salicylates and gallstes respectively, but, even after prolonged boiling, no reaction took place. Antimonious oxide was practically insoluble in the solutions, and arsenious oxide merely dissolved to the usual extent in the water of the solutions without forming any compounds with the salts present. In view of these results, experiments with hydroxy- beiizoic acids were not further prosecuted. Mooiybderctiw Tj-ioxide and Primary Tartrutes. To a boiling, aqueous solution of sodium hydrogen tartrate (2 mols.), molybdenum trioxide (1 mol.) was added in small quanti- ties until all was dissolved ; the solution was then filtered, cgncen- trated on the water bath, cooled, and niixed with alcohol, when a white, crystalline powder was precipitated.The crystals were puri- fied by dissolving them in water and reprecipitating with alcohol, repeating the process several times, and finally drying in air. Found. MOO,( NaC,H,O,),, 3H20. Calculated for Mo.. ...... 17.76 18-32 H,O ....... 10.52 10.30 The wat,er was determined in a vacuum over sulpliuric acid. Sodium molybditartrate was t'hus obtained in %he form of a white, Crystalline power, easily soluble in cold water, but only sparingly in dilute alcohol. When exposed to light, or when heated to about go", it decomposes, turning brown. If an aqueous soiution is boiled for some time, it turns blue, pointing to decomposition of the salt and reduction of the rnolybdic acid, and the addition of alkalis or mineral acids also causes decomposition. Molybdenum trioxide was also found to dissolve in a, boiling, aqueous solution of potassium hjdrogen tartrate, the same propor- tions being taken as in the preparation of the sodium salt, and, on the addition of alcohol to the solution, a gelatinous precipitate was formed, which solidified on standing in contact with the mother1456 HENDERSON AND RARR: THE ACTION OF liquor. The crystalline powder obtained in this \my was very soluble in water, but only sparingly in dilute alcohol, aud, like the sodium salt, i t decomposed on exposure to light or heat ; no doubt, it was the corresponding potassium salt, but,, owing to its instability, whicli rendered purification difficult, i t was not analysed.When ammonium hydrogen tartrate was used, the molybdenum trioxide was again found to dissolve, and, when alcohol was added to the solution, R gelatinous precipitate was thrown down ; but, this compound could not be obtained in R crystalline state.Twugsten T&Xide nicd l'&nar$ Ta!rtrates. Sodium fwzgstitartrate was prepared by adcling tungsten trioxide (1 mol.) to a boiling ayueoiis solution of sodium hydrogen tartrate (4 mols.) in small quantities until all was dissolved. I n this case it was necessary to use excess of the tartrate, for otherwise some decomposition took place, and the solubion turned blue when boiled for any length of time. When dissolution o€ the oxide was com- pleted, the solution was conccntrated on the water babli, the excess of tartrate removed by crystdlisntion, and alcohol added t:, the liquid ; a colourless syrnp was then precipitated, which solidified after standing for some time i n contact with tbe mother liquor.The crystals were purified by dissolving them in water and reprecipitating with alcohol, the operation being repeated unt'il the composition was constant. The salt was dried in the air and anslysed. Calculated for Found. W02 (NaC4H40G) r,5H20. W. .. .... .. 28-89 28.39 HZO . . . . . . 13.79 13-88 The water was determined at 100". The salt crystallises in white plates, which are easily soluble in water, hiit only sparingly in dilute alcohol. It begins to decompose when heated t o about loo", and the addition of alkalis or mineral acids to the solution also causes decomposition. Potassiam tungstiturtrate, W02( KC,H,O6),,4~H2O, was prepared and purified in a similar manner. Like the sodium salt, it is pre- cipitated by alcohol as a colourless syrup, which solidifies on standing. It is then obtained as a white, crystalline powder, fairly soluble in hot, but only very sparingly in cold water. It is decomposed by heat, and by the addition of alkalis or mineral acids to its solution, or when its aqueous solution is boiled for any length of time. Analpis of the air-dried salt gave the following figures. Found, W = 28.03, H,O = 12.85; calculated, W = 27-42, R,O = 12.07. The same process was used in prepai+ing the ammonium salt, and crystals were obtained, oE wbich the composition approximatedCERTAIN ACIDIC OXIDES ON SALTS OF HYDROXY-ACIDS. 1457 to the formula W02(NH~CiH~06)2,2H20, but the mlt was not prepared free from all impurity, as it readily decomposes when heated with water. The harizcm sa2t is precipitated on adding bariam acetate to a solu- tion of the sodium salt; it is a white powder, insoluble in water. Analysis of the washed and air-dried precipitate gave the following figures. Calculated for Found. WO2(C4H4Ob=)2Ba. w ............ 27.34 28.35 Ba 21.61 21-11 ............ Chemical Laboratory, Clasgozo und West of Scotland Technical College.

ISSN:0368-1645    

DOI:10.1039/CT8966901451

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

CERTAIN ACIDIC OXIDES ON SALTS OF HYDROXY-ACIDS. 1457 XCV.-Some Derivatives of Pyopionic acid, o f Acrylic ucid, ccnd of Gluturic acid. By WILLIAM HENRY PEXBIN, jun. ! ~ E S E researches originated in an attempt to prepare synthetically an acid of the formula CH*COOH \/- C(CHS)*COOH which Bredt (Ber., 1893, 26, 3049) first proposed as being a very probable expression of the constitution of camphoric acid. The starting point selected was a~~-trirneth~lprop.;Mzic acid (methyl- isopropylacetic acid), and this was prepared by a method already described by Romburgh (Iiec. ITrav. Chim,., 1886,6,236), namely, the distillation of methylisopropylmalonic acid. CH(CH3)2*C(CH,) (COOH)2 = CH(CH~)2~CH(CH~)*COOH + Cop The very carefully purified acid was then converted into ethylic 2-brmotrimethyZpropionate, CH(CH,),*CBr( CHr,)*COOC,H5, by first treating it with phosphorus and bromine (Hell, Ber., 1881,14, 891 ; Volhard, Annalen, 1887, 242, 161), and subsequently pouring the product into absolute alcohol.If now this ethereal salt were treated with alcoholic potash, i t should yield an unsaturated acid, CsBl0O2, and in the formation of this acid it was anticipated that the elimination of hydrogen VOL. LXIX, 5 F1458 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, bromide would take place between the bromine atom and the B-hydrogen atom marked * thus : C&(CH3)z*CBr(CH3)GOOC2H, + 2 K 0 H = C(CH,)2:C(CH3)*COOK + C,H5*OH + KBr + HzO, with formation of apB-triiitethylacl.yl~~ acid, and not between the bromine atom and a hydrogen atom of the a-met,hyl group, to form a-isopropylacrylic acid, CH(CH3),*CBr(CH3)*COOC2H, + 2KOH = CH(CH,)2*C(:CH,)*COOK + C2H5*0H + KBr + H20, because i t is generally found that the hydrogen atom in the C H of the isopropyl group reacts much more readily than the hydrogen atoms i n methyl or ethyl groups.Now, as Auwers and many others have shown, the ethereal salts of ap-unsaturated acids readily condense with the sodium derivative of ethylic malonate, forming additive products ; for example, in the case where ethylic acrylate is employed, the substance formed is ethylic propanetricarboxylate : (COOC2H5)2CH2 + CH,:CH*COOC,H5 = (COOC,H,)2CH*CH2*CH,.C 00 C2H5. As this reaction takes place in all the cases which have so far been investigated, it seemed probable that if etlhylic tri methylacrylate were digested in alcoholic solution with the sodium derivative of ethylic mttlonate, a similar condensation would take place, and that ethylic trimethyl;propanetricarboxylate would be formed, thus : (GO 0 C2Ha),CH2 + C (CH3) 2:C (CH,).COO C2H6 = (COOC2€3,)2CH*C (CH,)2*CH(CH,) *COOC2H5.This ethereal salt would be a most interesting substance in many ways, as, apart from the capabilit,y, which it would possess, of form- ing a sodium compound, ( C 0 0 C2H,),CNa*C ( CK,) ,*CH( CH,) COO C2H6, and its consequent value in synthetical work, it would, 011 hydrolysis, yield a tribasic acid, which, when heated, would lose 1 mol. of carbon dioxide, with formation of ap/3-t,.iineth?llgZutaric acid. ( C 0 OH) zCH* C ( C Ha) 2. C H ( CH3) * C 0 0 H = C 0 0 H* C H2* C ( C H,) 2-C H (C H3) *C 0 OH + C 0 2 .It would be very interesting to synthesise this aeid, in order to compare the synthetical acid with an acid which L. Balbiano (Rer., 1895, 28, 1507) obtained from a product of the oxidation of cam- phoric acid with cold potassium permanganate, and which this chemist considers to be c+@trirnethylglutaric acid.OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1459 I n using ethylic trimethylpropaneti~icarboxylate for the synthesis of camphoric acid, i t was next proposed to treat its sodium derivative with ethylene chlorhydrin, in order in this way to prepare ethylic hydroxyet h y ltrimeth y lpropanetricarbozy late, thus : (C 0 OC2H5)2CNa.C( CH,),*C H( CR,) G O OCaHj + C H,Cl*C H,*OH = (CO OCsHj),*C (CH,*CH2OH).C(CH3),*C H (CH3) *CO OC2H5 + NaCl, a decomposition which might be expected to proceed in this way, since a strictly analogous reaction, namely, the synthesis of ethylic hydr- oxyethy lacetoacetate, CH3*CO*C H( CH,*C H2.0H)*C0 0 C2H5, by the interaction of ethylene chlorhydrin with the sodiam compound OE ethylic acetoacctate, has been accomplished by Chanlarow (Annalen, 1884, 226, 326).On hydrolping the ethereal salt thus obtained, the corresponding tribasic acid would be formed, and this, as it is a derivative of malonic acid, should, when carefully heated, lose 1 mol. of carbon dioxicie, with formation of It ydroxyetl~yItrtmeth?llglutaric ucid. ( C 0 0 H ) 2C ( C: H2*C H,*O H ) C ( C H3) ,*C H ( CH,) C 00 H = Lastly, as Bredt’s formula for camphoric acid represents this sub- stance as containing a 5-carbon ring, and as this ring is generally produced with great ease, it seemed possible that, by treatment with dehydrating agents, or by other means, an acid of this formula might be formed by the simple elimination of mater from hydroxyethyl- drimethylglutaric acid, thus : C 0 0 H* C H ( C H 2.CH2.0 H) C (C H3) 2. C H (C Ha) C 0 0 H + C 0 2 . CH-COOH CHCOOH /\ H z y )C(CH3), + H,O. j H 9*CH3 COOH In investigating the various reactions described above, very un- expected difficulties were met x i t h , necessitating a very careful examination of the methods of preparation and behaviour of a large number of interesting substances which had not previously been pre- pared, and I beg now t o lay before the Society an account of some of the experiments which have, so far, been carried out, reserving the description of the others for a future occasion. A s preliminary experiments soon showed that the preparation of pure a,@,&trirnethylpropionic acid, CH(CH,),*CH( CHJ*COOH, in quaotity required much time, and was a matter of considerable diffi- 5 ~ 21460 PERKIN : SOME DERIVATITES OF PROPIONIC ACID, culty, and as the preparation is a very expensive one, it was thought best, in the first place, to experiment with isoraleric acid (PP-&- methylpropionic acid), CH(CH,)2*CH2*COOH, in order to discover the conditions which would probably be most favourable for the sub- sequent work with the trimethyl acid.Pure isovaleric acid was brominated in the presence of phosphorus in the usual way, and the product converted into ethylic a-bromo- valerate, CH(CHJ2*CHBr*COOC2H5, by treatment with alcohol, the conditions for obtaining the best yield being carefully determined.In order now to eliminate hydrogen bromide from this brominated ethereal salt, if was either hydrolysed by means of alcoholic potash, CH(CH,)~*CHBI**COOC~H~ + 2KOH = C(CHs)2:CHCOOIC + CzH5*OH + KBr + H20, or digested with quinoline (compare Weinig, Annaten, 1894, 280). In the firat case, dimethylacrylic acid is at once obtained, whereas,. in the second case, its ethereal salt is produced, and as in the subse- quent experiments the latter waR nearly always required, the second method was most frequently employed. Dimethylacrylic acid has already been described by various investigators (see p.1469) : i t is a beautifully crystalline acid, which melts at 70' ; ethylic dimethyl- acrylate is a colourless oil and boils at 155'. The condensation of ethylic dimethylacrylate with the sodium derivative of ethylic malonate was next invest+ ted, and found t o proceed normally, ethylic dimethylpropnnetricarboxylate being formed,, thus : (COOC,H,),CH, -+ (CH,),C:CH*COOC2H, = (C 00 CZH,) ,CH*C( C H,) 2. CH2*C 00 C2H5- But the determination of the conditions for obtaining thc best yield of this condensation product gave a considerable amount of trouble, as, in working under the conditions usually employed, only a very small yield of the substance is obtained ; * ultimately, however, a method was devised by which it is posbible to prepare considerable quantities of this ethereal salt.Etlhylic dimethylpropanetricarboxy- late is a colourless oil, which boils at. 203' (60 mm.) ; on hydrolysis, * An abstract of this work on ethylic dimethylprop~netricarboxylate containing a description of @&dimethylglutaric acid and some of its derivatives, appeared some time since in the Proceediitgs (W. Goodwin and W. H. Perkin, jun., 189$, 64). Auwers (Ber., 1895, 28, 1130 ; Annaleia, 1896,292, 145), not knowing of this publication, eubsequently investigated the same subject, and obtained results which confirm, in a welcome way, those described here. Auwers also noticed that the yield of ethylic dimethylpropsnetricarboxylate, obtained by condensing ethylic dimethylacrylate with the sodium derivative of ethSlic malonate under the ordinary conditions, was very small, being only about 8 per cent.of the theoretical.OF ACRYLIC ACID, AND OF GLUTARlC ACID. 1461 it yields the corresponding tribasic acid (m. p. 173'), and this, when heated at 200°, loses carbon dioxide, with formation of /3,3-dimethyl- glutaric acid. ( C 0 OH) ,CH*C ( CH,),*CH2- C 0 0 H = This melts at lolo, and, when treated with acetic anhydride, is converted into the anhydride, C ( C H 3 ) 2 < ~ ~ $ ~ > 0 , which melts at 124O, or 23' higher than the acid itself, a very unusual thing, and especially interesting when it is remembered that camphoric acid, whicb is supposed by Bredt t o be a derivative of dimethylglutaric acid, yields an anhydride mhich melts 29-30' higher than the acid itself does. Dimethylacry lic acid yields a well cha.racterised anilic acid, COOH*CH2*C(CH3)2*CH2*CO*NH-C6Hs (m.p. 134O), and this, at its boiling point, is converted into the corresponding anil, C 0% + C 0 0 H. C H2* C (C H3) 2.C H 2.CO OH. which melts at 156-157'. One of the most remarkable points in connection with this acid is its abnormally high dissociation constant, the value found by Dr. James Walker being K = 0.0200. Dr. Pfaff subsequently examined the acid obtained by Auwera and Avery (Annalen, 1896, 232, 147), and confirmed tvhe above result, his determination giving the value K = 0.0220. The dissociation constants in the glutaric series gener- ally vary between 0*0050 and 0*0060, the only other exception to this rule, which has so far been observed, being, as Auwers points out, the aaa,-triruethylglutaric acid, C 0 OH* C (C H3) 2.C H2* C H ( CH,)*C 0 0 H, which has the low dissociation constant K = 0.0035.This point is again interesting in view of the possible connec- tion between camphoric acid and ljp-dimethylglutaric acid, but in this respect the values for the two acids are widely different, the dissociation constant of camphoric acid (K = 0~00225) being abnormally low . While the above experiments were i n progress and Dearly com- pleted, a similar series of reactions, starting with aPP-trimethylpropi- onic acid, CH(CH,),.CH (CX&COOH, in the place of isovaleric acid, were being pushed forward. In the first place, this acid was treated with bromine in the pres- ence of phosphorus, under the same conditions as those employed in1462 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, the case of isovaleric acid, and the product was decomposed by the addition of alcohol.In this way n very good yield of ethylic a- brom 0- app- trimeth y lp ropion a t e, C H (C H,) ,* C R r (C H3) CO 0 H, was o b- tained as a colourless oil boiling at 130° (100 mm.) without decom- position. This ethereal salt, on hydrolysis with alcoholic potash, or when digested with quinoline, behaved, to all appearance, exactly as described above in t'he case of ethylic bromisovalerate, yielding, in the first instance, an oily acid boiling at 204-205', and, in the second case, an ethereal salt boiling, not very constantly, at 162-167' ; and for a long time it was believed t h a t these reactions proceeded in the following manner : (1) CH(CH3),*CBr(CH3)*C:OOCZH, + 2KOH = (2) CH(CH3),*CBr(CH3)*COOC2H6 = HBr + C(CH3)2X(CH3)*COOK + KBr + H,O + C,H,*OH; C (CH3) 2: C( CH3)*COO C,H5 ; that the acid was, in fact, trimethylacyylic acid, and the ethereal salt ethy lic trimethylawylate. As the work progressed it was, however, soon seen that it was most important to be perfectly sure that the constitution of these substances is that given above, and this was found to be a dificult matter, and entailed many months' work.A quantity of the acid boiling a t 200--205° was prepared by t h e hydrolysis of ethylic bromotrimethylpropionate, and also by t h e hydrolysis of the ethereal salt produced by digeating this bromo- ethereal salt with quinoline, the oily acid obtained in both cases appa- rently having the same composition. When this oily acid is allowed to stand for a long time in a cool place, it gradually deposits thick prismatic crystals ; these were collected and purified by recrystallisa- tion; they then melted at 70-'71', and were subsequently proved to consist of pure a@/?-trimethy Zacry Zic acid, C (CH,),:C(CH,)*COOH. This acid combines with bromine to form a/3-dibro~~ao-a~~-trimethyl- propionic acid, CBr(CH,),.CBr(CH,)*COOH (m.p. 1 9 1 O ) ; with hydrogen bromide it yields p- bromotrimethylpyopionic acid, CB 1. (CH3) 2.C H ( C H3)' C 0 0 H (m. p. 8S0), and with hydrogen iodide, p-iodotrimethylpropionic acid (m. p. €32'); the formation of these substances, which takes place almost quantitatively in each case, was used as a means of characterising and identifying the acid.In order to prove that the above acid was in reality trimethyl- acrylic acid, it was necessary to prepare it by some method which left no doubt as to its constitution, and this was ultimately accom-OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1463 plished by employing a reaction which was first devised by Frank- land and Duppa, and which has lately come into some prominence owing to the researches of Reformatsky and others. Frankland and Duppa showed that a-hydroxy-derivatives of the fatty ac.ids may be prepared synthetically by the action of zinc on a mixture of methylic oxalate and an alkylic balo'id ; methylic hydroxy- isobutyrate, for example, is formed when zinc acts on a mixture of methylic oxalate and methylic iodide (AnnnZen, 1865, 133, 80) ; this reaction may be conveniently represented thus : Q(CH,),*OZnI COOCH, (?(CH3'2'0H + ZI~(OH)~ + HI.COOCH, Ir. I + 2H20 = + Zn(OCH3)I. + 2Zn + SUH,I = COOCH, C(CH3),*OZnI COOCH3 1. I COOCH, Reformatsky (.Journal of the Russian Chemical Society, 1890, 22, 49) subsequently extended this reaction to ketones aEd ethereal salts of a-halogen fatty acids, and succeeded in this way in spthesising P-hydroxy-fatty acids. As an example of this important method, the action of zinc on a mixture of acetone and ethylic monochlor- acetate may be given. I. (CH3)2C0 + CH2CI*COOC2H5 + Zn = C(CH,)2(OZnC1)*CH2.COOC2H5. OH*C(CH3)2*CH2*COOC2H5 + Zn(OH)* + HCI. With the aid of this reaction, trimethylacrylic acid may be pre- pared in a way which clearly proves its constitution, and in carrying out the experiment on this point, I was fortunate in having the assistance of Dr.J. F. Thorpe. When a mixture of acetone and ethylic a-bromopropionate is treated with zinc, under snitable conditions, condensation readily takes place, with formation of a peculiar zinc compound, the reaction evidently proceeding in the following way : (CH3)2C0 + CHBr(CH3)*COOC2H, = C ( CH3) 2 ( 0 ZnB r) C H ( C H,) C 0 0 C2H,. This zinc compound is decomposed, on treatment with water and dilute sulphuric acid, with formation of efhyZic t3-hydrozy-aPP-lri- inethyZpopionate, a thick, colourless oil which distils at 105' (30 mm.) without decomposing. 11. C(CH,)~(OZUC~).CH~.COOC~E~ + 2H20 = C(CH3)2(OZnBr)*CH(CH3)*COOC2H6 + 2H20 = OH*C(CH3)2*CH(CH3)*COOC2H5 + Zn(OH)2 + HBr.This ethereal salt, on hydrolysis, yields the corresponding hydroxy- acid, a colourless oil which distils at 160' (35 ram.), and which is1464 PERRIN : SOME DERIVATIVES OF PROPIONIC ACID, very readily acted on by concentrated aqueous hydrobromic and hydriodic acids, yielding P-brornot,rimethylpropionic acid, CBr( CH&.CH( CH,) GOOH, and /3-iodotrimethylpropionic acid respectively, substances which are identical with the acids already mentioned as being produced by the addition of hydrogen bromide and hydrogen iodide to trimet hylacrylic acid. Lastly, trimethylacrylic acid (m. p. 70') is obtained when [3-bromotrimethylpropionic acid is treated with alcoholic potash, CBr(CH3)2*CH(CH3)*COOH = C(CH3)2:C(CH3)*COOH + HBr; and as this same acid is also formed by the elimination of hydrogen bromide from a-bromotriniethylpropionic acid, it can only Lave the constitution represented by the formula C(CH3)2:C(CH,)-COOH.These experiments proved conclusively that the ethereal salt formed by the action of quinoline on et hylic a-bromotrimethylpropionate as described above, consists, certainly in part, of ethylic trimethylacrlp- late, and for a long time it was thought that it, was composed wholly of this compound. On this assumption, the experiments on the con. densation of this ethereal salt with the sodium compound of ethylic malonate were proceeded with, and a condensation product was obtained, which was naturally supposed t o be ethylic trinzethylrpro- pa netricar boxytate, (COOG;?H,)2CH2 + C(CH3)2:C(CH,)*COOC*H6 = (COOC,H,)2CH*C (CH&*CH( CH,)*COOC&H,.Unfortunately the yield of this new substance is very small, milch smaller, indeed, than the yield of ethylic dime thylpropanetricnrb- oxylate from ethjlic dimethylacrylate, and a large number of experi- ments carried out under the most varyiug conditions failed to increase the yield to more than about 10 per cent. of the theoretical. The substances used in this reaction are so difficult to prepare that it, was almost impossible to continue the experiments unless the yield of condensation prod uct could be considerably increased, and in order bo get over the difficulty, experiments on the action of ethylic a- bromotrimethy1propicinate on the sodium derivative of ethylic malon- ate were next instituted. In this decomposition, which takes place readily, it was, of course, possible that the two substances would react normally, with formation of ethylic methylisopropglethanetri- carboxylate, thus- (COOC2H5),CHNa + COOC2Hb*CBr( CH,)*CH(CH,), = (COOC2H,),CH*C(COOC2H,)(CH,)*CH(CH,), + NsBr.but, judging from the behnviour of other a-bromo-ethereal salts, such as, for example, e th y lic a-bmmoisobuty ra t e, CB r (CH,) ,*COO C2H5, nnder similar Gircumstances, it seemed probable that the reactionOF ACRYLIC ACID, AND OF GLUTARIC ACID. 1465 would take place in two stages, that is, that ethylic trimethylacry- late, C(CH3),:C(CH3)*COOC2H5, would be first formed by the elimi- nation of hydrogen bromide, and that this unsaturated ethereal salt would then condense with the ethylic malonate present to form ethylic trimetl~ylpropanetricarboxylate, as explained above.It was thought likely that, at the moment of formation, the ethylic trimethylacrylate might condense more readily with the ethylic malonate, and give a larger yield of condensation product. Both these assumptions were found to be correct., as not only did a careful comparison or" the product obtained prom that it was identical with the condensation product obtained on digesting the sodium derivative of ethylic mrtlonnte with the supposed ethglic trimethylacrylate as described above ;* but the yield was also considerably larger, being, indeed, sometimes considerably over 20 per cent. of the theoretical, and as this method of preparation involves fewer operations, and therefore requires much less time, it was used in all subsequent preparations of this ethereal salt.In the course of a careful investigation of the condensation pro- duct obtained by either of the above methods, several facts came to Jight which made i t doubtful whether, after all, the substance was really eth ylic trime th ylpropane tricerboxy iat e. The condensation product, on hydrolysis, yields a beautifully crystalline tribasic acid, which, when heated at 200°, readily loses l. mol. of carbon dioxide, with formation of a crystalline dibasic acid, which should be a&%trimethyl- glutaric acid. (COOH),CH*C( CH,),*CH( CH,)*COOH = CO, + COOH*CH2*C(CH~),*CH(CH~)*COOH. The acid thus produced is very similar to the acid which Balbiano (Bey., 1895, 28, 1507) obtained from camphoric acid, and which is very probably ap/3-trimethylglutaric acid; the former melts at 94-95O, and gives an anilic acid, meltingat 258-159', whereas the latter melts at 89", and yields an anilic acid melting at 150°, but the anhydrides of the two acids differ consideqably, that from the acid obtained by me melting a t 53", whereas the anhydride of Balbi_a_no's acid melts at But, because the acid is not identical with Balbiano's acid, it does not prove that it is not apl/3-trimelhylglutaric acid, for the reason that the constitution of Balbiano's acid is not known with certainty ; 80-a 10.* These experiments were conducted, in the usual manner, in alcoholic solution ; in x2lene solution, aleo, the reaction proceeds in the same way, which is rather remarkable, as usually the uneaturated intermediate substance is not so readily formed from a-bromo-ethereal salts under these conditions, the product consisting, a t all events to a large extent, of the normal ethane dqivative.1466 PERKIN: SOME DERIVATIVES OF PROPIONIC ACID, the latter might, for example, quite well be aap-trimethyl~lutaric acid, COOH*C(CH3),*CH(CH,)*C&*COOH, nevertheless it seemed desirable to further investigate the subject, and, as the result, it was ultimately conclusively proved that the synthetical acid is not tri- met h ylglu t aric acid, but a-isop ropy1 g lu t aric acid, C H (CH3) 2*CH (C 0 0 H) *CH2* CH, C 0 0 H.On oxidation with chromic acid the acid yields, besides acetic acid, only succinic acid, whereas from trimethylglutaric acid under these circumstances trimethylsuccinic acid should be formed.C H ( C H3) C H (C 0 0 H) CI&-C H2* C 0 0 H. ' Isopropylgluhric acid. C 0 OH*/ CH2- C (CH3),*C H ( CH,) C 0 0 H. ' Trimethylglutaric acid. Subsequently it was shown that the acid is identical with the isopropylglutaric acid, which, for the sake of comparison, was syn- thesised by Mr. Heinke and myself from the product of the action of ethylic /%iodopropionate on the sodium compound of ethylic isc- propylmalonate, by hydrolysis and subsequent elimination of carbon dioxide. I. C H (C H3) 2.CN a ( C 0 0 C2H5) + I* CHz*C Hz* C 0 0 C,H, = NaI + CH (C H&*C (C 00 C2H5)z*CHz*C H2.C 00 C2H3. I I. C H (C H3) 2. C ( C 0 0 H) Z*CHz*CH2*C 0 OH = C02 + CH(CHa)2*CH(COOH)*CHz*CHz*COOH* A careful re-investigation of the whole matter showed that when ethylic a-bromotrimethylpropionate is treated with quinoline, the product does not consist entirely of ethylic trimethylacrglate, but is x mixture of this subdance with ethylic a-isopropylacrylate, the elimination of hydrogen bromide from the brom-ethereal salt having taken place in two directions. CH (CHs),*C (C 0 0 C2H5) : C H2, ...... - . I:. (CH,) 'L GH- C B r (C 0 0 C2H5) *C H3 = C(CH3)2:C(COOC2H',)-CH3 + HBr. . ........................... I....... . 11. (CH&CH*CBr (C 00 C2H,) CH3 = (CH&J3H*C(COOC2H5):CH2 + HBr- When these mixed ethereal salts are digested with the sodium derivatire of ethylic malonate, the ethylic isopropylacrylate alone enteis into the reaction.OF ACRYLIC ACID, AND OF GLUTARIC ACID.1467 (COOC2H5)zCHz + CH2:C(COOC2&)*CR(CH,), = (CO OC2H,),C H a C H,* C H (C 0 OC,H,) *C H (CH,) 2.. Ethylic isopropylpropanetricarboxylate. The ethylic trimethylacrylate takes apparently" .no part in the con- densation, and, indeed, the latter snbstance may be, at all events, partially recovered from the product of the action. This behaviour of ethylic trimethylacrylate is very remarkable, and, so far, without parallel ; very probably t.he further investigation of the condensation of a/3-unsaturated ethereal salts with the sodium, derivatives of ethylic malonate and allied compounds mill show the nature and number of the groups, which, when attached to the double band, render the condensation a matter of difficulty, or, in some cases, prevent it altogether.During the course of these experiments, and while it was thought that the condensation product described above had the constitution, (CC)O C2H5) ,CHt* C( C H,),*CH( C H)3* CO 0 C,H5, experiments were being made on the introduction of the group -CH,-CH,*OH, at the point marked t, for the reasons given at the commencement of this paper. These experiments were not in the first instance actually made with this condensation product, owing to the great difficulty of obtaining it in any quantity, but with somewhat similarly constitnted sub- stances which could be more readily prepared. Arguing from t h e results of Chanlarow's experiments on the action of ethylene chlor- hydrin on the sodium derivative of ethylic acetoacetate (Annulen, 1884, 226, 326), it seemed probable that the best way of achieving the object in view would be to treat the sodium compound of this condensation product with ethylene chlorhydrin, but although many experiments were made on the action of this substance on the sodium derivatives of ethylic methylmalonate, ethylic isopropylmalonate, and on the corresponding mono-substitution derivatives of ethylic aceto- acetate, in no case could more than traces of the hydroxyethyl sub- stitution product be isolated, the unaltered ethereal salt being in all cases recovered almost quantitatively.This want of success led to the investigation of the action of yphenoxyethylic bromide, C6H5-O-CH2*CH2Br, on the sodium deri- vatives of ethylic malonat e, ethylic methylmalonate, and similarly constituted compounds ; a description of tbese experiments, all of which gave satisfactory results, has already appeared in the Transac- * A careful examination of the mother liquors from the crystallisation of the isopropy lpropanetricarboxylic acid resulting from the hydrolysis of the ethylic salt produced by the condensation failed to reveal thc presence of even traces of tri- methylpropanetricarbox~lic acid.This acid may, neverthelees, of course have been ,present in small quantity and have escaped detection.1468 PEBKIN : SOME DERIVATWES OF PROPIONIC ACID, tions of this Society (W. H. Bentley, E. Hawortb, and W. H. Perkin, jun., 1896, 69, 161). While this preliminary work was in progress, the action of phenoxyethylic bromide and sodium ethoxide on ethylic dimethyl- propanetricsrboxylate wa8 being investigated, became this ethereal salt is much more readily prepared than the substance now known to be ethylic isopropylpropanctricarboxylate. In this case it was expected that the reaction would proceed thus.( COOC2H,),CNa*C ( CH3)2*CH2*COOC2H5 + CH2Br*CHz*O*C6H5 = (C 0 0C2H6) 2C (C H2*CHz*OC6Ht,)*C ( CHJ2*CH2*C OOC2H5 + NaBr. But on hydrolysing the product, an acid was obtained, which was not derived from an ethereal salt of this constitution ; this was sub- sequently shown to be diphenoxyethylmaloliic acid, (C6H,*O*CH2CH2)2C( COOH),, and identical with the acid obtained by the action of phenoxyethylic bromide and sodium ethoxide on ethglic malonate (Trans., 1896, 69, 169), a reaction which was, in fact, studied in order to prove the identity of the two acids.It seems probable that during the course of the above reaction the ethylic dimethylpropanetricaboxylate undergoes, i n the first instance, partial decomposition into ethylic malonate and ethylic dimethyl- ncrylate, (COOC2H,)2CH*C( CH,)2*CH,*COOC2H, = (COOC,H,),CH, + C(CH3),:CH*COOC,HS, a kind of decomposition which has been observed in other cases, but which is particularly remarkable in the present instance as being the exact reverse of the process which results .in the formation of the ethereal salt, namely, by the condensatlion OE ethylic malonate with ethylic dimethy lacry late in the presence of sodium ethoxide. The regenerated ethylio malonate then reacts with the phenoxyethylic bromide and sodium ethoxide, with formation of ethylic diphenoxy- ethylmalonate, ( c6H5*o*cn2-CH2)2C( COOC2H5)2.At first sight it would seem more likely that ethylic phenoxy- eth 9 lmalonate, C,H,O* C H2*CH2- CH (C 0 0 C2 H5)2 (this vol., p. 16 7), would be formed in this way, but probably the decomposition of the ethylic dimethylpropanetricarboxylate into ethylic malonate and ethylic dimet'hylacrylate is a gradual one, and thus the ethylic maloriate would always be in the presence of excess of sodium ethoxide and phenoxyethylic bromide. Although these experiments did not seem to indicate that there was much chance of the study of the action of phenoxyethylic bro- mide on the sodium compound of ethylic isopropylpropanetricarb-OF ACRYLIO ACID, AND OF QLUTARIC ACID. 1469 oxylate" giving the desired results, it was nevertheless decided to investigate this point, and the result was certainly unexpected, as the reaction in this case was fonnd to proceed i n a perfectly normal manner, thus.( COOCzH5)aCNa*CH,*CH( COOCzH5)*CH (C H3)2 4- C H:,Br*C H2*0*C6H5 + NaRr- The yield of ethylic phenoxyethy lisopropy lpropanetricarboxylute thus obtained is certainly not good, but there was no indication of i~ decomposition of the molecule similar to that observed i n the case of ethylic dimethylpropanetricarboxylate. On hydrolysing the product of the above reaction, the correspond- i n g tribasic acid is obtained as a beautifully crystalline substance, which melt? at 180°, decomposing a t the same time into carbon dioxide and phenoxyethylisopropylglutaric acid (m. p. 93"). COOH*Q H*CH,-QH*COOH C6H6*O*CH2-CH2 CH(CH& (COOC,H,)zC( CHz*CHz*OC6H,) *CH:,*CH( COOCzH,)*CH( CH,), When digested with hydrobromic acid, this acid yields quantities of phenol, and a new crystalline acid, which is probably bromethyl- isoprop yl gI u taric acid. COOH*$IH*CH,*qH*COOH CEzBr*CHz CH(CH3), This acid and the corresponding hydroxy-acid, which is formed by boiling the bromo-acid with sodium carbonate solution, appear to have very interesting properties, and will be made the snbjectl of a further investigation, the results of which I hope to lay before the Society in a short time.Some of the experimeuts described ilr this paper were carried out with the assistance of Dr. J. F. Thorpe and Mr. W. Goodwin; whew this has been the case I have stated the fact at the commencement of the section in question.I beg to thank these gentlemen, and also Messrs. W. H. Bentley, E. Haworth, and J. L. Heinke, for their valuable assistance during the whole course of this investigation. E x P E R I M P N T A L. j?,3-l)imethylacrylic acid, C(CH3),:CH.COOH. [With W. G o o ~ w r ~ . ] This acid has already been prepared by Miller (Annulen, 1881, 206, 261) by the elimination of water from /?-hydroxyisobntylformic Q This was of CouPee suppojed at the time to bs ethylic trimethylpropanetricarb- ox J late.1470 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID. acid, ( CH3)2C(OH)*CH2*COOH, by boiling it with dilute snlphuric acid, and by Duvillier ( A m . Clzim. Phys., [ 5 ] , 19, 428), by the action of sodium ethoxide on ethylic a-bromovalerate.Subsequently Weinig (Ai:nale?h, 1894, 280, 253) showed that a good yield of ethylic dimethylacrylate may be obtained by boiling ethylic a-bromovalerate with diet hylaniline. In our experiments, we used one of the two following processes, according as we required the free acid or its ethereal salt. 1. The hydrolysis OC ethplic a-bromovalerate with alcoholic potash. 2. The removal of hydrogen bromide from ethylic a-bromovalerate by means of quinoline. lMethod I. Prqaration of Dimethylacrylic acid.-Potash (100 grams) is dissolved in a small quantity of boiling 80 per cent. alcohol, the Eolution heated on a water bath in a flask connected with a reflux condenser, and then pure ethylic a-bromoisovalerate (100 grams) added as rapidly as possible through the condenser, As soon as the very rigorous action has siibsided, the heating is continued for about half an hour ; water is then added, the clear brownish solution evaporated unlil free from- alcohol, acidified, and extracted three times with.pure ether.The ethereal extract is dried over calcium chloride, the ether dis- tilled off, and the residue fractionated under the ordinary pressure, when nearly the whole passes over between 185' and 195' as a colour- less oil which, on standing, becomes completely filled with long, colourless crystals. These were freed from adhering oil by means of the pump, and purified by recrystallisation from light petroleum (b. p. 50-60') ; the oily mother liquor from the crystals, on careful fractionation, yields more of the crystalline acid ; ultimately a con- siderable quantity of aa unpleasant smelling, oily liquid is left which does not crystallise at ordinary temperatures, and the nature of which we have not investigated.Dimethylacrylic acid crystallises from light petroleum in long, colourless needles which melt at 69", and are readily soluble in alcohol, ether, and hot, light petroleum, sparingly soluble in water. The analpis of the acid gave the following results. C = 59.97 ; H = 8.02. I. 0.1439 gave 0.3164 C02 and 0.1040 H20. Ir. 0.1600 ,, 0.3495 ,, ,, 0.1157 ,, c' = 59.56; H = 8.03. C,H802 requires C: = 60.00 ; H = 8 0 per cent. Preparation of Ethylic DirnethylacryZate.-In the pre- paratiori of this ethereal salt, ethylic a-bromisovalerate wag digested with quinoline instead of with diethylaniline as proposed by Weinig (Anwalen, 1894, 280, 253), because i t was found that the former reacted more vigorously than the latter, and yielded a product con- Nethod II.OF ACRYLlC ACID, AND OF GLUTARTC ACID. 1471 +aining only traces of bromine ; the whole method requiring much less time than when diethylaniline is employed.Pnre ethylic a-bromisovalerate, in quantities of 50 grams, is heated i n a reflux apparatus with freshly distilled cod tar quinoline (75-100 grams), a thermometer being placed in the Iiquid to allow of the temperature being observed. At about 170-175', and as soon as the reaction sets in, the flame is removed ; the whole boi!s gently for some time, the temperature rising spontaneously to 190'. As soon as the .action has subsided, the liquid is heated at 185-190' for 10 minntes, the dark brown product poured into excess of dilute hydrochloric acid, extracted with ether, the ethereal solution washed with hydro- chloric acid, dried over calcium chloride, and the ether distilled off.If the ethereal salt is required free from bromine, it is again heated with about hslf its weight of quinoline in the same manner as before, and ultimately carefully fractionated ; after three fractiona- tions, almost the whole passes over between 154' and 155' as a colonr- less oil of penetrating odour. An analysis gave the following results. 0.1530 gave 0.3660 GO, and 0.1341 H20. When digested with excess of potash in methyl alcoholicz solution, ethylic dimethylacrylate is completely hydrolysed in less than one hour; it is not necessary to digest for 12-14 hours, as Weinig (Zoc.cit., p. 254) states. In order to isolate the dimethylacrylic acid, the product of the hydrolysis is evaporated with water until free from alcohol, acidified, extracted with ether, and purified as described under Method 1. The ethglic dimethylacrylate used in this research was prepared partly by the action of quinoline on ethylic a-bromisovalerste, as described above, and partly by the etherification of pure dimethyl- acrylic acid. I n the latter case, the pure acid (50 grams) was dissolved in absolute alcohol (100 grams), concentrated sulphuric acid (50 grams) added, and the whole allowed to staud over night. Water was then added, the ethereal salt extracted with ether, the ethereal solution washed with water and dilute sodium carbonate solution, dried over anhydrous potassium carbonate, and the ether distilled off.The residual ekhereal salt, on fractionation, distilled almost constantly at 254-155', but it did not give very good results on analysis. C = 65.24; H = 9-43. C7HI2OZ requires C = 65.62; H = 9.37 per cent. Found. I--- 7 Theory. I. 11. 111. CiHlZOZ. 33 ... .. .. . . 9.17 9.21 9.22 ,, 9.37 ,, C.. ........ 65.01 64.91 64-75 p. c. 65.62 p. c.1472 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, Ethylic L)imethylpropanetricarboxylate, ( C 0 0 C2H5) 2CH* C (C Ha) .L*C €I2* C 0 OC2H5. I n order to prepare this substance, pure ethylic dirnethylacrylat,e was digested i n alcoholic solution with excess of the sodium derivative of ethylic malonate, the quantities usually employed being the following.Ethylic malonate.. ........ 160 grams Sodium ,, .......... 23 ,, Alcohol ,, .......... 250 ,, Ethylic dimethylacrylate , . , 80 ,, [ Wi tli W. GOODW IN. 1 .The sodium was dissolved in the alcohol, the slightly warm soln- tion mixed with the ethylic malonste, the ethylic dimethylacrylate then added, and the whole heated in a reflus apparatus (or, in some cases, in soda-water bottles) for eight hours at 60', and then for eight hours on ft water bath. The opaque, slightly brownish pro- duct was mixed with water and dilute hydrochloric acid, extracted twice with ether, the ethereal solution well washed with water and dilute hydrochloric acid, dried over calcium chloride, evaporated, and the residual oil purified by fractionation under reduced pressure (60 mm.).After a considerable quantity of unchanged ethylic dimethylacrylate and ethylic malonate had passed over, the thermometer rose rapidly to 195O, almost the whole of the residue distilling between this tem- perature and 210'. Pure ethylic dimethylpropanetricarboxylate distils at 203' (60 mm.). Auwers (Zoc. cit., p. 113) found the boiling point to he 194' (43 mm.) ; he does not appear, however, to have analysed his product. The analyses of the ethereal salt prepared by us gave the following results. C = 58-00 ; H = 8-30, 11. 0.158 ,, 03375 ,, ,, 0.1183 ,, C = 58.25; H = 8-32. C,H,,Oe requires C = 58.33 ; H = 8-33 per cent. Ethylic dimethylpropanetricarboxylate is a moderately thick, colourless oil, which, when heated in small qnsntities, distils under the ordinary pressure almost without decomposition.The yield of this ethereal salt, obtained under the above conditions, Taried considerably in different experiments, amounting, as it did in more than one case, to over 40 per cent. of theory, whilst in one or two cases the yield was as low as 21 per cent. Auwers, in his experi- ments on the condensation of ethylic dimethylacrylate with etliylic malonate in alcoholic solution, obtained only 8 per cent. of the theoretical yield of this ethereal salt ; bst he worked under different eonditions from those we employed. I. 0.132 gave 0-2809 CO, and 0.0986 H,O.OF ACRYLIC ACID, AND OF QLUTARIC ACID. 1473 Dimethylpropanet?-carbo~yZ~c acid, (C OOH),CH*C (CH,),*CH,*COOH. In order to prepare this acid, 20 grams of pure ethylic dimethyl- propane t ricarbox ylate, in me thy1 alcoholic solution, was digested with excess of potash (20 grams) for two hoursin a reflux apparatus. The solution was then mixed with water, concentrated on a water bath, boiled until quite free from alcohol, cooled well, acidified, and extracted 20 times with ether.The ethereal solution, after drying over calcium chloride, was evaporated, and the residue allowed to stand over sulphuric acid in a vacuum desiccator until it had almost completely solidified. After standing for six days in contact with porous porcelain, the crystals, which were colourless and free from oil, were dissolved in a little water, and the solution filtered and saturated with hydrogen chloride, the whole being well cooled during the operation. The acid soon commenced t o separate in sandy crystals, which, after 24 hours, were collected, drained on a porous plake, dried at looo, aud analysed with the following results.0.1501 gave 0,2585 COa and 0.0815 H,O. C = 46.99; H = 6.04. Dimethylpropanetricarbooylic acid softens at 168", and decomposes a t 173' with rapid evolution of carbon dioxide. It is readily soluble in water and alcohol, much less SO in ether, and only very sparingly in hydrochloric acid, so that when its concentrated aqueous solution is saturated with hydrogen chloride the acid separates almost completely. The pure substance is very stable, and may be heated at 100' for a considerable time without appreciable decomposition. Salts.-A neutral solution of the ammonium saltpf the acid gives no precipitate with coppey sdphate or with barium or calcium chlovides ; but on the addition of lead acetate, a voluminous gelatin- ous precipitate is produced. The silver salt, CeHsOsAg3, was prepared by adding silver nitrate to a slightly alkaline solution of the ammonium salt ; it is a white, curdy precipitate, insoluble in water.After well washing and drying, first over sulphuric acid and then at loo', the following results were obtained on analysis. C8H,,0s requires C = 47.06 ; H = 5.88 per cent. I. 0-1809 gave on ignition 0*1108 Ag. Ag = 61-26. 11. 0-2159 ,, ,, 0.1325 ,, Ag = 61.37. C8HgOsAg3 requires Ag = 61-71 per cent. pp-Dimethylglutaric acid, COOH*CH,*C(CH,),*CH,*COOH. [With W. GOODWIN.] This acid is formed when dime thylpropnnetricarboxylic acid is VOL.LXIX. 5 G1474 PERKIN : SOME DERJVATIVES OF PROPIONIC ACID, heated above its melting point,. In carrying out this decomposition quantitatively, the following belinvionr was observed. 7.1825 grams of the tribasic acid heated in a wide test tube at 185-190' for 3-4 minutes lost 1.6070 gram = 22.4 per cent., but on continuing the heating for half an hour, the loss was 2.92 gram or 26.7 per cent. Theoretically, for the elimination of one molecule of carbon dioxide, the loss should he! 21.5 per cent. ; this agrees with the results obtained on heating the acid for a short time at 185- 190'. The further loss on prolonged heating is due to anhydride formation, and, to a small extent, to sublimation. The residue from this experiment solidified completely on cooling.It was powdered, dissolved in water, and the solntion saturated with hydrogen chloride. On standing, beautiful, colourless crystals sepa- rated, which, after drying at looo, gave the following results on analysis. C = 52.42 ; H = 7.72. PI. 0.1538 ,, 0.2962 ,, ,, 0.1071 ,, C = 52.53 : H = 7.73. I. 0.1694 gave 0.3256 C02 and 0.1177 H20. C7HI2Oc requires C = 52.50. H = 7.50 per cent. ,pp- Diinethylg lutaric acid is a colourless, crystalline substance which melts at 10Lo. It is very readily soluble in water, alcohol, and ether, but only sparingly in hydrochloric acid, benzene, and light petroleum ; i t crystsllises well froni water in colourless needles, but is most readily and economically obtained pure by recrystallisation from hot hydro- chloric acid, as described above, as in this way very little remains in the mother liquor.S i l v e ~ Salt, C7H1,Ag2O4.--This salt mas prepared by adding silver nitrate to the slightly alk a 1' me solution of the ammoninm salt. It is a white, insoluble precipitate, which, after well washing with water and drying a t looo, gave the following results on analysis. C = 22-38 ; Salts of pp-Di?nethylgZzlt~.ric acid. I. 0.1608 gave 0.1320 GO2, 0.0403 H20, and 0.093 Ag. H = 2.79; Ag = 57.83. 11. 0.201 on ignition gave 0.1159 Ag. C,H,,Ag2O4 requires C = 22.46 ; H = 2.66; Ag = 57.76 per cent. Ag = 57.66 A neixtral solution of the ammonium salt shows the following behaviour with reagents. Calcium cliloi-ide and Barium chloride give no precipitate even on boiling.Copper acetate gives no precipitate in the cold, but, on boiling, a light blue, apparently crystalline precipi- tate separates. Lead acetate also gives no precipitate in the cold, but, on warming, the solution rapidly becomes turbid, and an amorphous lead salt separates.OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1475 Ethylic Dimethy Zglutnrate, cOOc,H,.Ca,*C(GH,>,*CH~*~OOC,H~. This was prepared by dissolving the pure acid i n absolute alcohol, adding concentrated sulphuric acid (+ vol.), arid allowing the mixture t o staud for two clays ; it was then heated in the water bath for two hours, mixed with water, and the oily ethereal salt extracted with ether. The ethereal extract was washed well with dilute sodium carbonate, dried over anhydrous potassium carbonate, evaporated, and the resid ual oil purified by distillation under reduced pressure, when almost the whole quantity passed over a t 170-172" (100 mm.).C = 60.89 ; I€ = 9.28. 11. 0.1407 ,, 0.3126 ,, ,, 0.1184 ,, C = 60.59 ; H = 9.35. C,,H,,04 requires C = 61.11 ; H = 9.26 per cent. Ethylic dirriethylglutarate distils, apparently without decomposition, at 241-243' (755 mm.), or only slightly higher than efhylic glutarate, which boils at 237" ; it has a faint odour somewhat resembling that of ethylic succinate. I. 0.2011 gave 0.4488 CO, and 0.1680 H,O. Dimethy Zg Zutar ic An?) y dr ide, C (C H3) < CHZ*CO CH,. > 0. [With W. Goouwr~.] Dimethylglutaric acid dissolves readily in hot acetic anhydride, and if the solution is heated in a test-tube in a sulphuric acid bath until the excess of acetic anhydride has distilled oE, the residue solidifies on cooling to a hard, crystalline cake.The crystals were spread on porous porcelain until free from mother liquor, and dried at 100' ; they then melted a t 124', and, after recrystallisation from acetic anhydride, a t 124-125", C = 58.72 ; H = 7-20. 11. 0.1249 ,, 0.2674 ,, 0.0803 ,, c' = 58.79; H = 7.19. C~H1003 requires C = 59.16; H = 7-04 per cent. Dimethylglutaric a&$ride cry s t a k e s from acetic anhydride, in which i t is very soluble, in thin plates; these, aftor drying well between filter paper, smell of acetic anhydride, and become quite sticky in the water oven, and remain so for at least an hour, so that it is possible that these crystals consist of a mixed anhydride of acetic and dimetbylglutaric acids, which, on heating, decompose into acetic anhydride and dimethylglutaric anhydride ; this point has, however, not been further investigated.Dimethylglutaric anhydride is readily soluble in benzene, but only sparingly in light petroleum (b. p. 40-50'), it dissolves, however, in petroleum boiling a t 110-120°, and on cooling ci.ystallises out in plates. It is insoluble in cold water, b u t on heating it melts under water, and rapidly dissolves. 5 ~ 2 I. 0.1376 gave 0.2960 CO, and 0.0892 H,O.1476 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, Dimethy7gZutaraniZic acid, C 00H*CH2*C (CH,),*C H,*U O*N EI*C6H5, and Dintet77yZglutaranZ1, C(CB,),<cHf.co>N*C,H,. CH *CO If a solution of dimethylglutaric anhydride i n a little benzene is mixed with the calculated quantity of freshly distilled aniline, the mixture gets hot and rapidly begins to deposit crystals ; these, after being collechd and drained on porous porcelain, are crptailised two or three times from dilute alcohol.0.1461 gave 7.7 C.C. moist nitrogen at 17' and 7.56 mm. N = 6.12. Di~ethylglzctarnnilic acid melts at about 134O, but if slowly heated it softens at about 128' and melts at 131'. It is very readily soluble in alcohol and chloroform, but only sparingly in water, benzene, and light petroleum; it crystallises from dilute alcohol in small, hard, glistening prisms, and very beautifully, in similar form, when its solution in chloroform is allowed to evaporate spontaneously. DimethyZgZutarnniZ is obtained by heating the anilic acid to boiling for 10 minutes, in a test-tube; water is given off, and, on cooling, the residue solidifies completely.After recrystallising t mice from dilute alcohol, the anil is obtained pure in colourless, glistening plates, which melt at 156-157'. 0.1380 gave 7.8 C.C. moist nitrogen at 18" and 760 mm. N = 6.52. C,,H,JO, requires N = 6.45 per cent. Dimethylglutaranil is readily soluble in alcohol, benzene, and CL3H17N03 requires N = 5.96 per cent. chloroform, but only sparingly in water or light petroleum. a/3/3- Trimethylpropionic acid, C H (C H3),*C H (CH,) *C 0 0 H. This acid has already been prepared by Markownikoff (Zeit. f. C H (C H3) 2*C H ( C HJ C N,, by hydrolysis, and also by Romburgh (Rec. Trav. Chinz., 1886,5, 231) by the hydrolysis of ethylic methyl isopropylacetoacetate, and by the distillation of methylisopropylmalonic acid, Chem., 1866, 502) from methylisopropylcarbinyl cyanide, CH3.C 0 *C ( CH3) (CSHT) *C 0 0 CZHs, C ( C H3) ( C3H7) ( C 0 0 H) 2- In preparing large quantities of this acid, I have used exclusively the latter method: as, however, the isolation of the pure acid was found t o be a matter of considerable difficulty, I give the method of preparation in full.In the first place, ethylic methylmalonate was prepared by the action of methylic iodide on the sodium derivative ofOF ACRYLIC ACID, AND OF GLUTARIC ACID. 1477 ethylic malonates in alcoholic solution, great care being taken by using a slight excess (about 5 per cent'.) of the calculated quantity of sodium, and a considerable excess of methylic iodide, that the product should be as free from ethylic malonate as possible. I n subseqiiently introducing the isopropyl group into the carefully fractioned ethylic methylmalonate, the following method was found convenient.Ethylic methylmalonnte (345 grams) is mixed with sodium (46 grams) dissolved in alcohol (500 grams) in a large flask con- nected with a very long reflux condenser ; isopropylic bromide (260 grams) is then added, and the whole very gently warmed, the action being kept well under control, otherwise the whole begins to boil very vigorously, and much isopropylic bromide escapes through the condenser. As soon as the principal reaction is ovm, the mass is heated to boiling for six hours, the bulk of the alcohol distilled off, water added, and the oil which separates extracted three times with ether; the ethereal solution, after washing well with water and eraporating, deposits a nearly colonrless oil, from which, by repeated fractiona- tion, 330 grams, or about 75 per cent.of the theoretical yield of nearly pure ethylic methylisopropylrnalonate, boiling at 21 7-222', can be obtained. 0.1451 gave 0.3190 CO, and 0.1162 H,O. C,,H,,O, requires C = 61.11; H = 9.26 per cent. This ethereal salt was hydrolysed by digesting it for two hours with potash (260 grams) dissolved in purified methylated spirit ; water was then added, and the product heated first on a water bath and finally boiled over a free flame till quite free from alcohol ; the concentrated solution was then acidified and extracted six times with pure ether.The ethereal solution, after drying over calcium chloride and evaporating, deposited about 280 grams of an oily acid, which still contained some ether, and, on standing, rapidly began t o crystal- lise. This crude product was now heated at 180-200' until the evolution of carbon dioxide had ceased, and the residue distilled with- out, in the first imtance, attempting to fractionate. The crude distillate always contains traces of propionic and iso- valeric acids, and it is remarkable that pure methylisopropylacetic acid can only be isolated from this with very considerable difficulty, Q I n carrying out thie prepamtion with large quantities of material, the rnethylic iodide must be added very cautiously in small quantities to the alcoholic solution of the sodium derivative of ethylic malonate, the whole being well cooled during the operation, otherwise the action is very violent, and if care be not taken, the liquid boils most vigorously, with loss of methylic iodide from volatilisation, and frequently from frothing over.C = 60.80; H = 9.03.1478 PERKIN : SOXE DERIVATIVES OF PROPIONIC ACIII, repeated fractionation from a flask fitted with a long colonna being necessary, in order to effect as complete a separation a s possible. Ultimately, however, about 180 grams of an oil boiling constantly at 189-190' were obtained, which consisted of nearly pure methyl- isopropylacetic acid, as the following analyses show. I. 0.1606 gave 0.3622 CO, and 0.3.440 H,O. C = 61-50 ; H = 9.96. I I .0.1314 ,, 0.2952 ,, ,, 0.1220 ,, C: = 61.27; H = 10.34. C,H120, requires C = 62-07 ; H = 10.34 per cent. Tq-imethyZpmpionic acid is a most disagreeably smelling mobile Rornbzcrgh (Zoc. cit.) found prac- liquid, which boils at 189-190'. tically the same boiling point, namely, 189-191 '. Ethy Zic a-Bromotrimethy~~oloio?Lute, C H (CH&* C Br (C H,)*C 0 0 C,H,. The bromination of methylisopropylacetic acid is very readily carried out by treating the acid bromide with bromine according to Volhard's method (Anizalen, 1887, 242, ISl), and as the result of a number of experiments, the followiiig quantities were found to give the best results. I n a flask, into the neck of which along condensing Cube is ground, methylisopropylacetic acid (50 grams) is mixed with phosphorus pentabromide (75 grams) and allowed to remain for about one houP, until the formation of the acid bromide is complete.Dry bromine (85 grams) is then added in about six portions, the flask being cooled between each addition ; the liquid is then heated gradually on a water bath to about 50-60°, until the action is nearly complete, and finally at 100' for two hours. The well cooied product, which is usually coloured, owing to the presence of a slight excess of bromine, is poured in a thin stream into three times its volume of absolute alcohol, the vigorous action being allowed to proceed without cooling ; after standing overnight, water is added, and the bromo-ethereal salt is extracted with et*her. The ethereal solution, after washing with water and dilute sodium carbon- ate solution, drying over calcium chloride, and evaporating, deposits a somewhat brownish oil, which, on fractionating twice under reduced pressure (100 mm.), boils for the most part constantly at 130', the yield being usual17 good, although, in one or two cases, not inconsiderable quantities of some higher boiling Substance was obtained.The analysis of the pure substance gave the following result. 0.2035 gram substance, heated with fuming nitric acid and silver nitrate at 180' for four hours, gave 0.1722 gram AgBr = 36.0t per cent. of bromine. C,HI5BrO, reqnires Br = 35.89 per cent.OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1479 Ethylic a-bromotrinaeth~~r~p~onate is a heavy, very pungent smell- ing, colourless oil, very similar to ethylic a-bromisovalerate in its general properties.Trimeth y Zac~y Zic acid, C (C H,) 2: C (C H3) *C 0 0 H. As stated in the introduction, this acid was first prepared by the hydrolysis of ethylic methylisopropylbromacetate with alcoholic potash. Potash (100 grams) was dissolved i n the smallest possible quantity of SO per cent. alcohol in a flask connected with a long reflux con- denser, the solution heated on a boiling water bath, and hhen the pure bromo-ethereal salt (100 grams) added as rapidly as possible through the condenser tube. After the very vigorous action had subsided, the whole was heated to boiling €or about an hour, water was added, t'he brown solution evaporated until quite free from alcohol, aciditied, and extracted five times with pure ether. The ethereal solution was then dried over calcium chloride, evaporated, and the residue fractionated two or three times under reduced pressure, and subsequently &.the ordinary pressure, in order to separate the trimethylacrylic acid as far as possible from a considerable quantity oE a-hydroxytrimethyl- propionic acid (p.1486), which is formed at the same time. In this way, an oily acid was obtained, boiling constantly at 204-205' (under 100 mm. pressure it boils at 150'), and consisting of a mixture of the two isomeric a.cids, isopropylacrylic acid and tri- methylacrylic acid. It gave the following results on analysis. 0,1641 gave 0.3760 CO, and 0.1320 H,O. C6H,,0, requires C = 65-15; H = 8.77 per cent. During the winter months, this oily acid gradually deposited a quantity of beautiful, prismatic, four sided crystals ; these were col- lected with the aid of the pump, drained on porous porcelain, and recrystallised from l i g h t petroleum. The new substance was thus readily obtained in a pure state, and gave the following numbers on analysis.C = 62-64 ; H = 8.94. 11. 0.1441 ,, 0.3334 ,, ,, 0.1155 ,, C = 63.10; H = 8-90. C(CH3),:C(CH3)COOH requires C.= 63.15; H = 8-77 per cent. TrinaethyZac~ylic acid, when moderately rapidly heated in a capillary tube, softens at 67', and melts at 79-71'. I t is readily soluble in hot light petroleum, benzene, alcohol, ether, and chloroform, sparingly in hot water. The hot concentrated aqueous solution becomes milky on standing, and then gradually deposits crystals, but, on slowly cool- ing a hot dilute aqueous solution, the acid crystallises well in long, colourless needles.C = 62.5; H = 8.93, I. 0.1312 gave 0 3014 CO, and 0.1056 H,O.1480 PERKIN: SOME DERIVATIVES OF PROPIONIC ACID, The solution of the pure acid in sodium carbonate decolorises potassium permanganate, but not nearly so rapidly as many other unsaturated acids. Triinet h3ZacryZic Anilide, C( C H3) z:C ( CHJ *C 0 *NH*C6H5. This substance was prepared in the following way. Pure tii- methylacrylic acid was mixed with excess of freshly distilled phos- phorus trichloride, and, as very little action appeared to take place in the cold, the whole was heated on the water bath for about 15 minutes. On fractionating the product, a considerable quantity distilled a t 145-150', and evidently consisted of trimethylacrylic chloride, C(CH3)2:C(CH3)*COC1.This was dissolved in pure dry ether, mixed with excess of aniline, and, as soon as the very vigorous action had subsided, the whole was treated with water and extracted with ether. The ethereal solution was washed first with dilute hydrochloric acid and then with sodium carbonate, dried over anhydrous potassium carbonate, and the ether distilled off, when a syrupy residue was obtained, which, on standing, gradually solidified, In order t o purify this crude substance, it was ground up with cold light petroleum, collected on a filter, and recrystallised twice from boiling light petroleum (b. p. 70-80"). 0,2133 gave 14.0 C.C. moist nitrogen at 20" and 765 mm. N = 7.55. T~imethylacrylic anilide melts at 93-94', and crystallises from hot light petroleum in beautiful, glistening plates.It is readily soluble in alcohol, ether, and benzene, sparingly in light petroleum, and almost insoluble in water. ClzHl5NO requires N = 7.41 per cent. Dibromotrimethyl33ropionic acid, CBr(CH,),*CBr(CH,)*COOH. A solution of trimethylacrylic acid in chloroform decolorises bro- mine rapidly, and if, after the addition of the calculatled quantity of bromine, the liquid is allowed to evaporate spontaneously, a semi- solid residue is obtained, consisting of impure dibromo trimethyl- propionic acid. The crude product was left in contact with porous porcelain for some days until the oily impurities had been entirely absorbed, and the solid residue purified by recrystallisation from light petroleum (b.p. 100-105'). 0.1547 gram substance, heated with nitric acid and nitrate of silver at 180°, gave 0.2128 gram AgBr ; Br = 58.54. C6H,,,Br20, requires Br = 58.40 per cent. Dibromotrimethy kropionic acid is very sparingly soluble in cold light petroleum, but dissolves fairly readily on warming, and separatesOF ACRYLIC ACID, AND OF GLUTARIC ACID. 1481 again, on standing, as a heavy, white, crystalline powder. When heated in a capillary tube, it sinters at 185', and melts at 190-L9lo wit,h rapid evolution of gas. P- Bromotrimethy ~ r o p i o n i c acid, CBr (CH,),*C H (CH,) *COOH. In order t o prepare this substance, finely powdered trimethylacrylic acid (1 gram) was mixed in a test tube with 5 C.C. of fuming hydro- bromic acid saturated at 0'. On gently warming the mixture, the acid completely dissolved, but very soon an oily layer formed on the surface.After standing for 10 minutes, an equal volume of water was added, and the crystals which separated were collected, well washed with water, drained on a porous plate, and dried over sulphuric acid in a vacuum. As the substance could not be satisfac- torily recrystallised, the colourless, crystalline mass obtained in this way was directly analysed. 0.1431 gram substance, heated at 200' with nitric acid and nitrate of silver, gave 0.1375 gram AgBr. Br = 40.92. CsHl,BrOz requires Br = 41.02 per cent. p-BromotrimetjLylpro~ionic acid, when heated in a capillary tube, softens at 83' and melts at about 87-88'. It is readily soluble in most, organic solvents, but practically insoluble in water.When boiled with water, it is rapidly decomposed with separation of hydrogen bromide. p- Iodotrimeth yZpropionic acid, CI (CH, ),*CH( C H,) GOOH. Trimethylacrylic acid dissolves readily i n f nming hydriodic acid (sp. gr. 1-96> in the cold, and, on standing, the solution gradually deposits beautiful crystals of P-iodotrimethylpropionic acid. After diluting with water, the crystals were collected, washed well with water, and dried on a piece of porous porcelain over sulphuric acid in a vacuum. The analysis of the glistening, crystalline mass thus obtained gave the following results. 0,1439 gram substmce, heated with silver nitrate and nitric acid at 170°, gave 0.1390 gram AgI. I = 52.23. CsH,,IO2 requires I = 52.48 per cent. p-Iodotrimethylpropiolzic acid melts at 80--82O, and, when heated in a test tube, i t rapidly decomposes wifh separation of iodine and evolution of hydrogen iodide; it also decomposes on exposure to strong sunlight, with separation of iodine.It is readily soluble in alcohol, light petroleum, chloroform, and ether, but almost insoluble in cold water. Cold concentrated nitric acid decomposes it instantly, with separation of crystals of iodine.1482 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, Condensation. 19 Aceto?be with Ethylic a-B1.onzopl.opiorante. Pormation of Eth y lic p- H~di.oxy-alj~-trimeth~~p~op~o~~at e, 0H.C (CH3)2*CH(CH,)*COOC,H,. [With J. F. THOKPE.] This condensation was studied, as explained in the introduction, with the object of synthesising trimethylacrylic acid, C ( CH,) ,:C (C H3) *C 0 0 H, and its derivatives by a method which could leave no doubt as t o their constitution, and the results obtained served to prove conclu- sively that the solid acid (melting at 71') produced, as already described, by the hydrolysis of ethylic bromotrimethylpropionate,. was in fact this acid, and not isopropylacq-lic acid, C H (C H3) 2.C (:CH2) C 0 OH, a s was at one time thought to be the case.The first step was to prepare ethylic P-hydroxy-app-trimethylpro- pionate, and this is accomplished as follows. Acetone (90 grams) is mixed with ethylic a-bromopropionate (182 grams), ar?d the mixture poured on to an excess of dry and carefully cleaned zinc in a moderately large flask connected with a reffux a,ppa- ratus. The zinc, which should be in the form of turnings, must be quite free from oil, and it is also essential that it should be quite dry.We found it necessary to wash it several times with hot caustic soda, then with dilute acid to remove any oxide, and finally to wash i t well with water and dry it with alcohol and ether. Experi- ments conducted with zinc which had not been treated in this way were always unsuccessful. The flask containing a little of the zinc in contact with the mixture is now gently warmed on the water bath, when, as boon as the temperature has risen to about 50°, the action usually commences and continues very energetically ; the flask is removed from the water bath if necessary, but as a rule the excess of acetone employed serves to prevent the temperature from rising too high.When the reaction has subsided, if i t is found that nearly all the zinc has disappeared, more is added, and the whole ultimately heated on the water bath for about 2-3 hours ; a t the end of this time the contents of the flask will have become quite thick and slightly colonred. The syrupy liquid is poured off as far as possible from the un- changed zinc, and mixed with water ; this causes the mass to become nearly solid, owing to the separation of a white zinc compound, which, however, disappears on adding dilute sulphuric acid and shaking vigorously. The oil which separates is extracted by means of ether,OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1483 the ethereal solution is washed three times with dilute sulphuric acid in order to remove the last traces of zinc, dried over calcium chloride, the ether distilled off, and the residual oil purified by careful fractionation under reduced pressure (30 mm.).A considerable portion of the product distils below looo, and appears tolconsist essentially of ethylic propionate and ethylic acry- late, the former produced by the reduetion of, and the latter by t,he elimination of hydiaogen bromide from, the et hylic a-bromopropiona te employed in this synthesis. About 50 per cent. of the whole distils at 105' (30 mm.) as a moderately thick, colourless oil of very faint odour, which after redistillation gave the follomiiig I-esults on analysis. C = 60.16; H = 10.08, 11. 0.1309 ?, 0.2872 ,, ,, 0.1198 ,, C = 59.82; H = 10.16. C,H,,O, requires C = 60-00; H = 10 00 per cent. This substance consists, therefore, of pure ethylic P-Jydroxy-a/3/3-tri- 1.0.1186 gtve 0.2616 C02 and 0.1076 H20. meth ylpropionate. /3-Hydrox y-app- t ~ i m ei hy Zpropionic acid, 0H.C ( C H3) 2*C H (CH,) * C 0 0 H . [With J. F. THORPE.] I n order to prepare this acid, the corresponding ethereal salt just described was mixed with excess of a solution of potash (14 mols.) in pure alcohol, and heated on the water bath for two hours. Water was then added, the solution evaporated until quite free from alcohol, acidified, and extracted several times with pure ether, the extraction being much facilitated by saturating the solution with ammonium snlphate. The ethereal solution was carefully dried over calcium chloride, filtered, evaporated, and the thick, syrupy residue purified by distillation in small quantities under reduced pressure ; almost the whole passed over at 160' (35 mm.) as a very thick, viscid, colour- less oil which, on analysis, gave the following numbers.I. 0.1888 gave 0.3814 CO, and 0.1592 H20. C = 55.08 ; H = 9.37. If. 0.1318 ,, 0.2650 ,, ,, 0.1106 ,, C = 54.83; H = 9.32. C,H,,O, requires C = 54.54 ; H = 9.09 per cent. /J-Hyd?.ozy-aPS-trimethylpi-opionicc acid is a very thick syrup, which even on long standing does not show any signs of crystallising. I t is readily soluble in water, the solution having a strongly acid reac- tion. When distilled in large quantities (100 grams), it decomposes with elimination of water and formation of trimethylacrylic acid. The dissociation constant for the electrical conductivity of this acid at different concentrations was determined by Dr.Ewan, who found K = 0.00333.1484 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, /3- Bromo-apB- t rim eth y Zpropionic acid, CBr ( CHJ 2 * C H ( CH,) C 0 OH. [With J. P. THORPE.] This substance, which is identical with the bromo-acid obtained by the addition of hydrogen bromide to trimethglacrylic acid (p. l48l), is obtained by dissolving /3-hyclroxytrimethylpropionic acid in fuming hydrobromic acid (saturated at -10'). The mixture becomes warm, and, on standing, the bromo-acid rapidly separates in lustrous plates, which, after washing with water and drying on a porous plate oyer sulphuric acid in a vacuum, melt at 86-88'. 0.2012 gram substance, heated at 180' with silver nitrate and nitric acid, gave 0.1919 gram AgBr.Br = $0.98 per cent, C,H,,BrO2 requires Br = 41.02 per cent. E th y 1 ic /I- bromo-a Pp-t rimeth y lpropionaie, C(CH3)2Br*CH(CH3)*C:OOC2H5.-[With J. F. THORPE.] In order t o prepare this compound for some synthetical experi- ments described below, the etcherification of the corresponding acid by means of alcohol and sulphuric acid, and by saturating the solu- tion of the acid in alcohol with hydrogen chloride was tried, but with very unsatisfactory results. Ultimately, however, the ethereal salt was prepared in considerable quantity, with ease, i n the following way. The pure dry bromo-acid (10 grams) was mixed with phosphorus pentachloride (12 grams) and allowed t o stand until the somewhat energetic action had subsided: the whole was t,hen heated on the water bath for 15-20 minutes, and the product poured into absolute alcohol and allowed to stand over night.On adding water, a heavy, brownish oil was precipitated; this was extracted with ether, the ethereal solution well washed with water and dilute sodium carbonate, dried over calcium chloride, and the ether distilled off. The residual, somewhat brownish oil did not appear to distil without decomposi- tion ; but after standing over sulphuric acid in a vacuum for a few days, i t gave the following results on analysis, showing it to consist of the nearly pure ethereal salt. 0.2103 gave 0.1760 AgBr. Br = 35*96. C,H1502Br requires Br = 36.16 per cent. Many experiments with this substance mere made with the object of synthesising aPP-trimethglglutaric acid so as to be able to compare it with the acid Balbiano obtained by the oxidationof camphoric acid with cold potassium permanganate (Ber., 1895, 28, 1507) ; the method of procedure will be well understood fi-om the following equations.OF ACRYLIC ACID, AND OF GLUTARIC ACID.1485 I. (COO C2H,),CHNa + CBr (C H,) ,*C H (C H,)*COOC,H, = (CO OC,H,),CH*C (CH,),*CH (CH,) *CO OC,H, + NaBr. rr. (COOH),CH~~:(CH,),~CH(CH,)~COOH = C 0 OH.CH2.C (CH3)z.C H (CH,)*C OOH + C02. The action of the brom-ethereal salt on the sodium derivative of ethylic malonate was tried under various conditions in alcoholic and xylene solution, but only very small quantities of a high boiling con- densation product were formed in any case, and similar results were obtained when ettylic cyanoacetate was employed.Apparently in all these experimeuts the bromo-ethereal salt is to some extent decom- posed with elimination of hydrogen bromide and formation of ethylic trimethylacrylate ; the reaction, however, is evidently a complicated one, as is shown by the fact that in all the above experiments the pro- duct was found to contain considerable quantities of ethylic ethane- tetracarboxyl ate (COO C2H5),CH.C H (COOC,H,) 2. p-Iodo-app-trilnethyZlrro~'ionic acid, C ( CH,),I*CH(CH3)-COOH. /3-Hydroxytrimethylpropionic acid dissolves readily in fuming hydriodic acid, and, on standing, crystals of the above substance separate rapidly. The crystals were collected, washed with water, dried on a porous plate over sulphuric acid in the dark, and analysed.0.1296 gave 0.1252 AgI. I = 52.39. C6H,,T-O2 requires I = 52.48 per cent. This acid melts at 80' and is identical with the compound obtained by the addition of hydrogen iodide to trimethylacrylic acid (p. 1481). When it is treated with phosphorous pentachloride, and the product is poured into alcohol under exactly the same conditions as described in the case of the corresponding bromo-acid, it yields a heavy ethereal salt, which cannot be distilled without decomposition; it was not analysed. Trimethylucrytic acid, C(CH3),:C (CH,)*COOH.-[With J. F. THORPE.] This a3d is produced when alcoholic potash, or weak alkalis, such as the sodium derivative of ethylic malonate, act on ethylic P-bromo- trimethylpropionate. It was first obtained from this ethereal salt, in the following manner.The low boiling fractions from the product of the action of the bromo-ethereal salt on the sodium derivative of ethylic malonate (see above) were hydrolysed by boiling for three hours with an excess of alcoholic potash. The alkaline solution was then evaporated with water until free from alcohol, acidified, and extracted with ether ;1486 PERKIN : SOME DERIVATIVES O F PROPIONIC ACID, the ethereal solution after being dried over calcium chloride was evaporated, and the residual oil fractionated under reduced pressnre. The fraction boiling at 135-137' (50 mm.) solidified on cooling, and the crystals, after being drained on a porous plate and crystallised from water, consisted of pure triniethylacrylict acid melting at 70-71'. 0.2201 gave 0.5085 CO, and 0.1737 H,O.C6H,,O2 requires C = 63.15 ; H = 8.77 per cent. The silver salt, C6H9Ag02, was obtained as a white precipitate sparingly soluble in water, on adding silver nitrate t o the nentral solution of the ammonium salt. C = 63.00 ; H = 8.79. 02002, on ignition, gave 0.0970 dg. C6HgAg02 requires A g = 48.77 per cent. After these experiments had been carried out, it was found that the same acid was obtained by the hydrolysis of ethylic p-bromo- trimethylpropionate with alcoholic potash ; and the acid obtained in both cases was found to be identical with the trimethyacrylic acid obtained by the hydrolysis of ethylic a-bromotrimethylpro- pionate (p. 1479). As this was an important point, a sample of the tri- methylacrylic acid obtained from the /%brom-ether.eal salt by means of alcoholic potash was dissolved in chloroform and treated with bromine under the conditions described on p.1480. The resulting dibromide melted at 190-191", and was identical in all respects with the dibromotrimethylpropionic acid previously obtained. Br = 58.10. C6H,,Br0, requires Br = 58.40 per cent. Ag = 48.73. 0.1398 gave 0,191 AgBr. ol-Rydroxytr~methylpropionic acid, CH(CH,),*C (OH) (CH,)*COOH. I n distilling t'he crude acid obtained by the hydrolysis of ethylic a-bromotrimethylpropionate with alcoholic potash, a mixture of isopropylacrylic acid and trimethylacrylic acid at first passed over as explained on p. 1479 ; the thermometer then rose rapidly, and a thick colourless oil distilled over which after standing for some months deposited prismatic crystals.These were collected, drained on a porous plate, and purified by recrystallisation from light petroleum (b. p. 60-80'), when they were obtained in the form of glistening, colourless needles which, on analysis, gave the folio wing numbers. C = 54.73 ; H = 9.20. 11. 0.1601 ,, 0.3225 ,) ,, 0.1305 ,, C = 54.90; H = 9.06. 111. 0.1765 ,, 0.3511 ), ,, 0.1451 ,) C = 54.25; H = 9 12. C6H,,03 requires = 54.54 ; H = 9-09 per cent. I. 0.1931 gave 0.3874 CO, and 0.1598 H,O.OF ACRYLIC ACID: AND OF GLUTARIC ACID. 1487 cr-Hydrozytri~,2efhy~,.opio?ii~ acid melts a t 75-77', but not very sharply. It is very readily soluble in water, the solution possessing a very strong acid reaction. It is readily soluble in alcohol, ether, OY .chloroform, moderately in benzene, and sparingly in cold, light petroleum.When thrown on to the surface of water, the crystals of the acid rotate in a very vigorous manner and dissolve rapidly. The dissociation coilstant for the electrical condnctivitly of this acid a t different concentrations a t 2 5 O , was found b y Dr. Ewan to be K = 0.01135. It is remarkable that this value should be so high in comparison with the constant (K = 0.00333) for the corresponding p-hydroxy-acid (p. 1483). Salts of a- Hydrox ytrinaethy Zpropionic acid. The silver salt, C,H,,AgO,, obtained as a white precipitate on t h e addition of silver nitrate to a strong neutral solution of the ammonium salt of the acid, is sparingly soluble in cold water, but dissolves readily on boiling, and the hot solution on cooling deposits the salt in a beautifully crystalline condition.f Ag = 45.19. 0.2445 gave 0.1105 Ag. CsH,,Ag03 requires Ag = 45.18 per cent. This silver salt is not Feadily acted on by light, and may be dried a t 100' without decomposition ; its solution in dilute ammouia is only very slowly decomposed on boiling. A neutral solution of the ammonium salt of the acid shows the following behaviour with reagents. Copper acetate no precipitate in the cold, but, ,on boiling, a pale blue crystalline copper salt sepal-ates ; this gradually decomposes on prolonged boiling, especially if a little alkali be present, and cuprous oxide is precipitated. Barium and calcium chlorides, and lead acetate give no precipitate. Action of Hydrobroinic acid and Hydriodic acid O?L a-Hydroaytri- methyZpp.1.opionic acid.-This reaction was investigated in the hope of easily obtaining a-bron~otrimethylpropionic acid, C H (CH3) 2.C BI*( CH,) *C OOH, and a-iodotrimethylpropionic acid, CH(CH,),*CI(CH,)*COOH, for comparison with the cor~esponding @halogen derivatives which had been prepared from a-hydroxytrimethylpropionic acid and trimethyl- acrylic acid by the methods described on pp.1484-1485. It was found that p-hydroxytrimethylpropionic acid reacts very readily with con- centrated hydrobromic and hydriodic acids in the cold, formiiig the corresponding 8- halogen derivatives, but the behaviour of the tori-e- sponding a-hydroxy-acid is very different in this respect. The latter dissolves very readily in the concentrated halo'id acids, but no action1488 PERKIN : SOME DERIVATZVES OF PROPIONIC ACID, appears to take place, as was shown by the fact that, after remaining a t the ordinary temperature for 12 hours, no crystals had separated, and a drop of the liqiiid dissolved in water formed a clear solution.The solutions were then sealed up in tubes and heated in boiling water, but even then the action seemed to take place very slowly, the liquids only becomiiig turbid after two hours' boiling. After eight hours, the tubes were allowed to cool, when, on opening them, a considerable pressure was noticed, which was found to be due to carbon dioxide, and, on pouring the contents of the tubes into water, a heavy oil was precipitated in each case. This was extracted with ether, the ethereal solution washed well with water and dilate sodium carbonate (and, in the case of the hydriodic acid experiment, also with sodium thiosulphate to remove iodine), evaporated, and the nearly colourless, oily residues fractionated.After twice fractionating, in the case of the hydro- bromic acid experiment a small quantity of a heavy oil was obtained, which boiled at 115-120', and on analysis gave the following result. 0.1420 gram heated with silver nitrate and fuming nitric acid at Br = 51.10 per cent. C5HllBr requires Br = 58.98 per cent, Although, owing to the difficulty of purifying the small amount of material at my disposal, this analysis does not agree well with the formula C5HIIBr, i t seems probable that this bromide is identical with methylisopropylcarbinyl bromide, CH(CH,),*CHBi**CH,, which Wischnegradsky (Annalen, 1878, 190, 357) obtained by the action of hydrogen bromide on isopropylethylene, C H(CH,),*CH:CH,, and which boils at 114-116'.The formation of this substance would be readily explained by the following equation : CH(C€33)2*C(OH)(CHs)*COOH + HBr = 200' for 4 honrs gave 0.1711 grain AgBr. CH(CH,),*CHBr*CH, + C02 + H,O, but it is certainly remarkable that an a-bromo-fatty acid, which one ~ o u l d expect to be formed in the first instance, should lose carbon dioxide in this way, as this is a decomposition usually only shown by p-bromo-derivstivea. The oil obtained from the hydriodic acid experiment distilled roughly a t 125-130°, and is possibly methyliao- propylcarbinyl iodide, CH(CH&CHI*CH,, which, according to Wischnegradsky (A.nnnlsn, 1878, 190, 337), boils at 127-128' ; i t was not analysed.Preparation of the mixed Ethereal Salts of Isopropylacrylic acid and of Trimet h y lncry lic acid. The greater portion of these mixed ethereal salts used in the first experimeuts in this research was prepared by the etherification ofOF ACRYLlC ACID, AND OF GLUTARIC ACID. 1489 the mixture of isopropylacrylic and trimethylacrylic acids obtained by the hydrolysis of ethjlic a-bromotrimethylpropionate by means of alcoholic potash, as explained on p. 1462 (Method I). The action of quinoline on the brominated ethereal salt (Method I T ) was not inves- tigated until mosh of the experiments described in this paper had been completed. Method 1.-The mixed ethereal salts were prepared by dissolving the mixed acids (1 vol.) in absolute alcohol (3 vols.), and adding concentrated sulphnric acid (1 ~01.1.After standing overnight, water was added, the oily layer extracted with ether, the ethereal solution washed with sodium carbonate solution, dried over anhydrous potassium carbonate, evaporated, and the residual crude ethereal salt purified by repeated fractional distillation. Although this ethereal salt has been prepared in large quantities (500 grams) on several occasions, it has always been found very difficult to obtain a product of anything like constant boiling point, and, for this reason, in the experiments described in this paper the fraction 162-1'75' was usually employed. It is, of course, possible that the ethereal salts of the two acrylic acids may boil at different temperatures, but it is .more probable that the product contains small quantities of ethylic a-hydroxytrirnethylpropionate, produced .by the action of the sul- phuric acid on the unsaturated acids during the process of etherifica- tion, and this is borne out by the results obtained by the analysis of different fractions, which were always too low.I (b. p. 163-165') ; I. 0.1240 gave 03020 CO, and 0.1094 H20. C = 66.43 ; H = 9.80. 11. 0.1561 ,, 0.3758 ,, ,, 0.2360 ,, C = 65.66; H = 9.67. 111. 0.1404 ,, 0.3379 ,, ,, 0.1218 ,, C = 65.64; H = 9.64. CBHlaO2 requires C = 6'7.60; H = 9.86 per cent. The presence of the impurity, whatever it may be, in the fraction 162-175', does not interfere with the experiment for which it was employed (condensation with ethylic malonate), except, of course, in so far as it may affect the yield of the condensation product.Method II.-A mixture of ethylic a-bromotrimethylpropionate (100 grams) and quinoline (200 grams) was heated in a metal bath in a flask connected with a retlnx apparatus, the temperature of the mixture being observed by placing a thermometer in the liquid. When the temperature had risen to 175-180°, the reaction set in, and on removing the flame the liquid boiled, though not violently,for some minutes, the thermometer rising to about 19.5'. As soon as the action had subsided, the mixture was heated to boiling for 10 minutes, the well-cooled, dark reddish-brown product poured into an excess of dilute hydrochloric acid, and the oily layer extracted twice with ether.I1 (b. p. 166-168') ; I11 (b. p. 168-172"). VOL. LXIX. 5 H1490 PERKIN : SOME DERIVATIVES OF PROPLONIC ACID, After well washing with dilute hydrochloric acid and drying over calcium chloride, the ether was distilled off and the residual oil pnrified by repeated fractionation, when the greater part was found to distil between 162' and 175O, the quautity obtained being about 60-70 per cent. of the theoretical yield. This fraction, on analysis, gave only approxirna,tely correct results. 0.1364 gave 0.3344 C02 and 0.1209 H20. C8H,,02 requires C = 67.60; H = 9.85 per cent. In order to prove that thia ethereal salt was a mixture of the etbereal salts of isopropylacrylic and trimethylacrylic acids, it was hydrolysed by boiling with alcoholic potash in the usual manner.The acid obtained distilled at 148-150' (100 mm.), and, 011 standing in a freezing mixture, deposited crystals of trimethylacrylic acid. The filtrate from these crystals did not solidify on cooling, and was proved to contain isopropylacrylic acid. Apparently, then, the elimination of hydrogen bromide from ethylic a-bromotrimethylpropionate proceeds in the same way, whether alcoholic potaah or quinoline be employed, a mixture of iso- propylacrylic acid and trimethylacrylic acid, or their ethereal salts, being formed in both cases. C = 66.86 ; H = 9.86. Condensation of Rthylic Isopropylacrylate with the Sodium Derivative of Ethylic Malonate. Formation of Ethylic a-Isopropylpropane- aa,a,-tricarboxylate, (COOC~H~)zUH*CHz*CH(C,H7)*COOC,H,.The study of the reaction which takes place when trhe mixed ethereal salts of isopropylacrylic acid a i d trimethylacrylic acid are treated with the sodium compound of ethylic malonate has been made the subject of a very large number of experiments, carried out under very varying conditions, a description of which would occupy too much space to be given here. The product formed in every case was ethylic isopropylpropanetricarboxylate produced by the condensation of ethylic isopropylacrylate with ethylic malonate, the ethylic tri- methylacrylate, as explained in the introduction, apparently taking no part in tho reaction. The yield of condensation product was found to be much influenced by the purity of the unsaturated ethereal salts ; thus, for instance, when the mixture of eth ylic isopropylacrylate and ethy lic trimethyl- acrylate had been fractionated four times with a column, and the fraction 162-175' employed, a yield of 20 per cent.of the theoretical was obtained, whereas, in one case, where the ethereal salts had been fractionated only once, and the fraction 160-177° used f o r the con- densation, the yield was only 8 per cent.OF ACRYLIC ACID, AND OF GLUTARTC ACID. 1491 Ultimately, the condensation was usually carried out in the €01 low- ing way. I n a flask connected with a reflux condenser, sodinm (46 grams) was dissolved in absolute alcohol (500 grams), and then, while still slightly warm, first ethylic malonate (320 grams) and then the mix- tiire (164 grams) of the ethereal salts of isopropylacrylic acid and trimethylacrylic acid were added ; the product was subsequently heated for one day a t GOO, and then for two days on a water bath.The opaque, somewhat dark-coloured product was mixed with twice its volume of water, acidified with bydrochloric acid, and extracted three times with etlier ; the ethereal solution was washed well with water and dilute sodium carbonate, dried over calcium chloride, evaporated, and the residual oil fractionated under reduced pressure. The yield of crude product and the weight of the various fractions obt,ained varied very much, without any apparent cause ; the follow- i n g result was obtained in one case, where the products from an experiment carried out with the quantities given above were weighed. The yield of crude product was 244 grams, and this on fractionation under reduced pressure (80 mm.) gave the following fractions : Below 160° = 98 grams.160-220 = 16 ,, 220-235 = 92 ,, Residue = 16 ,, the fraction below 160" consists principally of ethylic trimethylacryl- ate, unchanged ethylic isopropylacrylate, and some unchanged ethylic malonate.* The fraction 220-235' is nearly pure ethylic isopropyl- propanetricarboxylate. The latter, on refractionation, boiled almost constantly at 208-210 (45 mm.), and gave the following resultst on analysis. I. 0.1610 gave 0.3486 COz and 0.1247 HzO. C = 59.04 ; H = 8.60. 11. 0.1392 ,, 0.2998 ,, ,, 0.1075 ,, C = 58.74 ; H = 8.50. 111. 0.1888 ,, 0.2796 ,, ,, 0.1000 ,, C = 59.20 ; H = 8.63. CI5Hz6O6 requires C = 59.60 ; H = 8.61 per cent.Ethylic isopropylpropanetricarboxylate is a thick, perfectly colour- less oil which boils at 208-210° under a pressure of 45 mm. ; it is isomeric with the ethereal salt obtained by treating the sodium com- pound of ethylic isopropy1malonat)e with ethylic P-iodopropionate (see p. 1507), and which has the formula (C 0 OCzH5)zC (C,H,) CHz* CH2.C 0 0 C2H5 ; It A large amount of tlie etliylic malonate eniployed in the above prepayation is t These analyses were carried out with the products obtained from three hjdrolysed during the prolonged heating. &ff erent preparations. 5 H 21492 PERKIN : SOME DERIVATIVES O F PROPIONIC ACID, both ehhereal salts are very similar in properties, and boil practically at the same temperatmre, and both, on hydrolysis and subsequent elimination of carbon dioxide, yield the same isopropylglutaric acid.E - Isoprop y 1p yopane- m,al- tricarboxy Eic acid, (C 00 H) ZCH*CHa* C H ( Cs H7) *C 0 0 H. The ethylic isopropylpropanetricarboxylate, prepared as described in the last paragraph, although it gives good repults on analysis, is not quite pure, but contains traces of other ethereal salts, and on this account, €or a considerable time, i t was found impossible to obtain crystalline isopropylglutaric acid from it by hydrolysis and subsequent elimi- nation of carbon dioxide. The oily acid obtained in this way refused to crystallise after standing for a month in a cool place, and even after converting it into its anhydride, fractionating this and regenerat- ing the acid, the product did not, crystallise.Ultimately it was discovered that pure isopropylpropanetricarboxylic acid may be readily purified by the following method, and that this pure acid, on subsequent heating at 180", yields piire isopropylglutaric acid which crystallises quite readily. Ethylic isopropylpropanetricarboxylate (40 grams) is hydrolysed by boiling for one hour with pure potash (50 grams) dissolved in mebhylic alcohol; the clear liquid is then mixed with water, and evaporated on a water bath, with the addition from time to time of small quantities of water, until every trace of methylic alcobol has been removed. The concentrated solution of the potassium salt, after acidifying, is extracted 10 times with pure ether (free from alcohol), the ether evaporated, the oily residue dissolved in twice its volume of water, and the solution saturated with hydrogen chloride, the temperature being kept below 40' by cooling with ice-cold water.During this operation, crystals begin to separate, and, on standing for two days, the bulk of the tribasic acid separates i n crystalline crusts ; tbese are collected on the pump, washed with concentrated hydrochloric acid, and purified by solution in water and saturation with hydrogen chloride as before. C = 49.36 ; H = 6.50. 11. 0.1243 ,, 0.2235 ,, ,, 0.0735 ,, C = 49.04; H = 6.57. C9Hl4O6 requires C = 49-54 ; H = 6.42 per cent. Isop~op~jlpropanetricart~o~~y lic acid, when moderately rapidly heated in a capillary tube, melts at 165' with rapid decomposition, due to evolution of carbon dioxide and formation of isopropy lglutaric acid, but if slowly heated, the decomposition takes place at a lower tem- perature, generally about 158".It is very readily soluble in water, I. 0.1130 gave 0,2045 CO, and 0.0661 H,O.OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1493 the solnt,ion possessing a very strong acid reaction, but it is only sparingly soluble in concentrated hydrochloric acid ; it dissolves also readily in alcohol, and moderately so in ether. Salts of Isopropylpropanetricayhoxylic acid.-The siltier salt was pyepared by adding silver nitrate to a fairly concentrated warm solu- tion of the ammonium salt. It is a white, amorphous precipitlate, which, after washing well with warm water, and drying first on a porous plate over sulphuric acid in a vacuum, and then at loo', gave the following result on analysis.0.3464, on ignition, gave 0.2064 Ag. C9HllAg306 requires Ag = 60.11 per cent. A neutral so1ut;ion of the ammonium salt gives no precipitate with calcium chEoride or copper acetate, but a white, gelatinous precipitate is formed with lead acetate. On the addition of barium chhide, no precipitate is produced at first, but on standing, or more rapidly on warming, an insoluble crystalline barium salt separates. Ag = 59.58. From the experiments already described i t seemed probable, as stated in the introduction, that when a mixture of ethylic isopropyl- acrylate and ethylic trimethylacrylate is digested with the sodium derivative of ethylic malonate, that the former alone undergoes con- densation, the latter remaining unchanged ; in order to determine, therefore, whether this was really the case the foliowing experiments were made.Experiment I.--The oil boiling below 160' (80 mm.), obtained in fractionating the product of the action of the mixed ethereal salts on ethylic malonate, as described on page 1491, was collected from several operations, carefully fractionated with a column, and the fraction 160-175' digested with a large excess of the sodiuni derivative of ethylic malonate in alcoholic solution, for about three days. The product was isolated as before, and, on fractionation, yielded a small qixantity of ethylic isopropylpropanetricarboxylate, shomiiig that small quantities of ethylic isopropylacrylate were present in the ethereal salt employed. The large quantity of oil of low boiling point, which was obtained during the fractionation, was again treated with ethylic malonate as before, and yielded now only traces of ethy lic isopropylpropanetricarboxylate ; it was very carefully frac- tionated, and the fraction boiling at 160-175O hydrolysed by boiling with alcoholic potash, and the acid obtained fractionated under reduced pressure, the fraction 135-142' (90 mm.) being collected separately.Owing to the mildness of the summer weather, this oil, which should contain the recovered trimethylacrylic acid, showed no signs of crystallising ; it was, therefore, dissolved in chloroform,1494 PERKIN : SOME DERlVATXVES OF PROPICNIC ACID. and titrated with bromine until the colour remained permanent, when about 80 per cent. of the theoretical quantity of bromine was absorbed, shon-ing that this crude acid must contain a small quantity of some saturated acid as impurity.On allowing the chloroform to evaporate spontaneously, crystals gradually separated from the oily residue : these were collected, spread on a porous plate, and recrys- tallised from light petroleum ; the substance then melted a.t 185-190°, and had all the properties of dibromotrimethylprupionic acid, CBr ( C El,),* C Br ( CH,) * CO OH. C,H,,Br,O, requires Br = 58.40 per cent. 0.1391 gave 0.1906 AgBr. Br = 58-58. The formation of this substance shows that when the mixture of ethylic isopropylacrylate and ethylic trimethylacrylate is digested with the sodium derivative of ethylic malonate, sowe of the latter, at all events, remains unattacked, even when the operation is repeated three times.Ahpeiiment 11.-Attempts were now made to determine whether any of the ethylic trimethylacrylate had taken part i n the reaction, in which case e thylic trimethyl propanetricarboxylate must have been formed, and, on hydrolysing the product of the condensation, tri- methylpropanetricarboxjlic acid, (C 0 0 €1) ?C H*C: ( C H3) 2*C LT ( C H3) C 0 0 H, would be obtained mixed with large quantities of isopropylpropane- tricarboxylic acid. If this were the case, the former acid muRt be contained in the hydrochloric acid mother liquors, from which the latter acid had crystallised out as explained on p. 1492. These mother liquors were collected, extracted about 20 times with pure ether, the ether evapo: rated, and the residual oily acid, dissolved in a little water, was saturated with hydrogen chloride, the whole being well cooled during the operation.After standing for a fortnight, the crystals of isopropylpropane- tricarboxylic acid which had separated were removed by filtration through tt platinum cone, the filtrate again extiacted with ether, and the treatment with hydrogen cbloride repeated. Lastly, the small quantity of acid which did not crystallise was heated at 180°, and the 1-esidue etherified by treatment with alcohol and sulphuric acid, when an oily, ethereal salt was obtained which distilled, for the most part, at 170-172' (90 mm.). As the acid obtained from this on hydrolysis did not solidify, it was converted into the anhydride by boiling with acetic anhydride, and the product (3 grams) fractionated, the fraction 170-175' (30 mm.) being reconverted into the acid ; the oily acid mas thenOF ACRYLIC ACID, AND OF OLUTARIC ACID.1495 dissolved in a little water, and the solution saturated with hydrogen chloride, On standing, about 1 gram of a crystalline acid separated which melted at 90-93', and consisted evidently of isopropylglu- taric acid, since it gave an anhydride melting at 53', and an anilic acid melting at 156-158'. As far as can be judged from these experiments, it appears that ethylic trimethylacrylate is not capable of condensing with ethylic malonate, and I hope to prove this definitely by experiments with pure e t hylic trime t h ylacry late. Isopropylqhttr& acid, CH (CH,),*CH (C OOH)*CH2*C H2*COOH.In order to prepare this acid, pure isopropylpropanetricarboxylic acid is heated in an oil bath at 200' until the evolution of carbon dioxide has entirely ceased ; the residue is dissolved in boiling water, and the solution, after cooling, saturated with hydrogen chloride. After standing overnight, the colourless crystals which separate are collected on a platinum cone by the aid of the pump, washed with concentrated hydrochloric acid, and reci*ystallised by dissolving them in a little water and saturating with hydrogen chloride as before. The analysis of this acid gave the following results. I. 0.1485 gave 0.2970 CO, and 0.1073 H20. C = 54.54 ; H = 8.03. 11. 0*1188 ,, 0.2385 ,, ,, 0.0858 ,, C = 54.82 ; H = 8-02. C8H,,OI requires C = 55.18 ; H = 8.05 per cent.It is readily soluble in water, and crystallises from the hot, concentrated solution, on cooling, in magnilicent, colourless prisms ; it is sparingly soluble in concen- trated hydrochloric acid, and is, therefore, most economically purified by saturating the aqueous solution with hydrogen chloride. The finely powdered crystals dissolve readily i u alcohol or ether, and moderately i n cold benzene, but the acid is almost insoluble in light petroleum. Isopropylglutaric ucid melts at 94-95O. Salts of Isopropylglutaric acid. The silver salt, C8H,,Ag204 was prepared by adding silver nitrate t o a slightly alkaline and fairly concentrated solution of the ammo- nium salt; the white flocculent precipitate was collected, washed with water, dried at loo", and analysed. I.0.2510 gave 0.2239 C02, 0.0702 H20, and 0.1396 Ag. C = 24.55 ; H = 3.10; Ag = 55.58. Ag = 55.70. 11. 0.2487, on ignition, gave 0.1385 Ag. CeH,,Ag20t requires C = 24.74; H = 3.10 ; Ag = 55.65 per cent. A dilute neutral solution of ammonium isopropylglutarate gives no precipitate with barium nitrate or calcium chloride. Copper sdphate1496 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, gives a bright green, gelatinous precipitate, and 2ead acetate, on warm- ing, a white, flocculent precipitate. E t h y Zic Isopropy l g Zutarate, C 00 C2Hs*CH (C&) C H2* C H2*C OOC2H5. This ethereal salt was prepared by dissolving the crude acid (obtained by heating pure isopropylpropanetricarboxylic acid at 200') in 4 vols. of absolute alcohol, and adding 1.5 vols. of concen- trated sulphuric acid.After standing for two days, water was added, the oily ethereal salt extracted with ether, the ethereal solution washed with water and sodium carbonate, dried over anhydrous potassium carbonate, and the residual oil purified by distillation under reduced pressure. Ethylic isopropylglntarate is a colonrless oil, having a strong, ethereal odour ; it boils at 158-160' (45 mm.). 0.1251 gave 0.2860 GOz and 0.1079 H20. C = 62.35 ; H ClzHz2O4requires C = 62-61 ; H = 9.56 per cent. = 9.59. yH2* CH2* CO CH(C~H,)*C o>O- Isopropylglutaric Anhydride, This is readily prepared from isopropylpropanetricarboxylic acid by heating it at 200' until the evolation of carbon dioxide has ceased, dissolving the residue in freshly distilled acetic anhydride, heating the solution to boiling for 10 minutes, and then placing it over solid potash in a vacuum desiccator.After some days, the crystals of the anhydride are collected, left in contact with porous porcelain until colourless, and then recrystallised from boiling light petroleum (b. p. 50-60'). The following results were obtained on analysis. 0.1448 gave 0.3280 CO, and 0.1007 H20. C = 61.17; H = 7.72. 0.1490 ,, 0.3336 ,, ,, 0.1017 ,, C = 61.06; H = 7-56, C8H1103 requires C = 61.54 ; H = 7*68 per cent. IsopropylgZutaric anhydride melts at about 53", but not quite sharply, and the melted substance, on cooling, sets to a transparent, jelly-like mass, which, on rubbing, soon becomes cryatalline and opaque. It is only sparingly soluble, even in boiling light petroleum (b.p. 50-SO'), and is almost completely deposited on cooling in very voluminous, feathery masses, consisting o€ slender needles, somewhat resembling cotton wool in appearance. It melts in boiling water, and dissolves only very slowly ; on concentrating the solution and allowing it to stand, isopropylglutaric acid separates in magnificent, colourless prisms.OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1497 Isopropy Eghtaranilic acid, C 0 OH*C Hz*CH2*CH ( C3H,) *CO*NH*CSH5, or COOH*CH(CsH7)*CHz*CH,*CO*NH*C~Ha (3). In order to prepare this substance, 0.9 gram of pure isopropyl- glutaric anhydride was dissolved in 5 C.C. of pure dry benzene, and 0.7 gram of freshly distilled aniline added ; this occasioned a con- siderable rise of temperature, and i n about a minute the whole crys- tallised.The crystals were collected, dyained on porous porcelain, and recrystallised from dilate methylic alcohol, when beautiful, colourless, glistening crystals were obtained, which gave the following results on analysis. 0.1384 gave 6.8 C.C. moist nitrogen at 18" and 755 mm. N = 5.64. C,H,,NO, requires N = 5.62 per cent. ~sTsopro~ylglutaranilic acid softens at 150°, and melts at 158-1 59'. It is readily soluble in alcohol, but only sparingly in benzene, light petroleum, or water. It does not appear to give off wster, even when heated at 250°, but when heated to boiling for some time in a test-tube, decomposition takes place, probably with formation of the anil; as, howevey, the product waB not readily purified, and I had very little substance at my disposal, the matter was not further in- vestigated.Oxidation of Isoproyylylutnric acid. Isopropylglutaric acid is only very slowly attacked by potassium dichromate and sulphuric acid even on boiling; 10 grams of the acid heated to boiling with 15 grams of potassium dichromate, 40 grams of concentrated sulphuric acid, and 300 C.C. of water for 10 days in a reflux apparatus, still contained unreduced chromic acid. The oxidation takes place, however, much more rapidly when the acid (10 grams) is digestled with chromic acid (30 gramsj and sulphuric acid (50 grams, diluted with 200 C.C. of water), the reduction of the chromic acid being complete after three days' boiling, The product from both experiments was distilled with steam until the condensed water ceased to have an acid reaction, the distillate was boiled with excess of barium carbonate, filtered, the filtrate evapo- rated to a small bulk, and precipitat,ed with silver nitrate.The white crystalline silver salt was collected with the aid of the pump, washed with water, dissolved in boiling. water, the hot solution filtered from traces OE reduced silver, and allowed to stand; the glistening crystals of pure silver acetate which separated were collected, dried at IOO", and analysed. 0.1940, on ignition, gave 0.1252 Ag. Ag = 64.54. The residue from the steam distillation was boiled with excess of CH,-COOAg requires Ag = 64.67 per cent.1498 PERKIN : SOXE DERIVATIVES OF PROPIONIC ACID, caustic ~ o ~ I I , , filtered from the chromium hydroxide, and the latter repeatedly washed with water; the combined liquors were then evaporated to a small bulk, acidified, and extracted three times with pure ether (A), and then again SO times with pure ether (13). The ethereal solution A, on evaporation, deposited a greeuisli crystalline acid, which, on recrystallisation from hydrochloric acid, at once yielded an acid, melting at 92-95', which proved to be uiiattacked isopropylglutaric acid. 0.1489 gave 0.2991 GO2 and 0.1075 H20.C,H,,02 requires C = 55.18 ; H = 8.05 per cent. The ethereal solution B, on evaporahion, yielded a greenish crys- talline mass, which contained only slight traces of isopropylglutayic acid. On repeatedly fractionally crystallising this substance from hydi*ochloi*ic acid , beautiful colourlesr;l crystals were ultimately obtained, which melted at 183-185', and consisted of pure succinic acid, as the following analysis shows : C = 54.78 ; H = 8.02.0*1100 gave 0.1639 CO, and 0.0523 H,O. C4H,04 requires C = 40.68; H = 5.10 per cent. No other acids could be isolated from the products of the oxida- tion, and it therefore follows that when boiled with chromic acid and sulphuric acid, isopropylglutaric acid is oxiilised with formation of acetic and succinic acids. C = 40.66 ; H = 5.28. Action of E'thplic a-Bronzotrimethylpropionate on the Soditmh Desizatit-e of Ethylic Jfalonate in Alcoholic Solutiorc. I n studying this decomposition, sodium (6 grams) was dissolved in alcohol (75 grams) in a flask connected with a reflux condenser, ethylic malonate (40 grams) and ethylic a-bromotrimethylpropionate (56 grams) were added, and the whole allowed to stand for some time.Very little action seemed to take place in the cold, but, on gently warming on a water bath, sodium bromide separated rapidly, the separation, after half ail hour, being apparently so complete that in the earlier experiments the action was stopped a t the end of this time ; subsequently, however, it was found that a very much larger yield of condensation product could be obtained if the liquid was kept in vigorous ebullition for 2-3 days. At the eiid OE this time, the alcohol was distilled off from a salt bath, the residue mixed with watw: the oil which WRS precipitated extracted with ether, the ethereal solution washed, well dried over calcium chloride, the ether distilled off, and the light brown, oily residue fractionated under reduced pressure (100 mm.).OF-ACRYLIC ACID, AND OF GLUTARIC ACIJ). 1499 About half of' this product distilled between 125' and 145O, the thermometer then rose rapidly, the greater bulk (22 grams) passing over between 222' and 230' (100 mm.) ; the latter, on refractiona- tion, distilled for the most part constantly at 220' (100 mm.) as a colourless oil, which gave the Eollowing numbers on analysis : 0.1501 gave 03255 GO, and 0.1168 H,O.C = 59.14 ; H = 8.65. The careful examination of this substance showed that it was not C,sH2606 requires C = 59.60 ; H = 8.61 per cent. ethylic methylisopropylethanetricarboxylate, but that it consisted of very nearly pure ethylic isopropylpropanetri- carboxylate (which it was expected would be formed during this reaction), identical with the product obtained by condensing ethylic isopropylacrylate with the sodium derivative of ethylic malonate (p.1491) ; this was proved in the following. way. The ethereal salt was hydrolysed with alcoholic potash, and the tricarboxylic acid isolated and purified exactly as described in the case of isopropylpropanetricarboxy~ic acid (p. 1492). The crystalline product, like the acid just named, melted at 163-165' with decom- position, and gave, on analysis, the following numbers : 0.1695 gave 0.3064 GOz and 0.1008 H,O. C = 49.30 ; H = 6-56, C9H,,06 requires C = 49.54 ; H = 6.42 per cent. 011 heating this acid at 200°, carbon dioxide was evolved, and the residue, after being twice recrystallised from hydrochloric acid, melted at 94-95', and consisted of isopropylglutark acid, as was ahown by converting it into its anhydride (m.p. 33'). and into isopropylglu- taranilk acid (m. p. 157-159'), and also from the results obtained on analysis. (C OOCaHb) C (CH,) (C3H,)*CH (COO CZH5)2, 0.1472 gave 0.2956 GO, and 0.1065 H,O. C,H,404 requires C = 55.18 ; H = 8.05 per cent. There can be no doubt that the product of the action of ethylic bromotrimethylpropionate on the sodium derivative of ethylic malotiate in alcoholic solution, is ethylic isopropylpropanetricarb- oxylate. C = 54-77; H = 8.10. Action of h'thylic Bromot,-imethylp'rprop~onate on the Xodiuin Derivative of Ethylic Maloiaate in Xylene Solutioiz. As stated in the introduction to this paper, it has often been found that in cases where a glutaric acid derivative is formed by t h e action of an a-bromo-ethereal salt on the sodium derivative of ethylic malonate in alcoholic sohition, a widely different result mar be1500 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, obtained by substituting xylene for alcohol as the solvent, the product consisting then for the most part of a derivative of succinic acid.In order t o determine whether this would be the case in the present instance, the following experiment was made. Sodium (3 grams) was melted under boiling xylene and the whole violently agitated so as to bring the sodium into a state of the finest possible division, ethylic malonate (20 grams) was then added, and the whole heated to boiling in a reflux apparatus until the sodium had completely dis- appearzd ; ethglic a-bromotrimethylpropionate (28 grams) was then added, and tbe mixture heated to boiling for two days. The brownish product was shaken with water and a quantity of ether, the ethereal solution was beparated, washed well with water and dilute hydro- chloric acid, dried over calcium chloride, and the ether and xylene distilled off, at first under ordinary, but subsequently under reduced pressure.On fractionating the oily residue under 100 mm. pressure, the greater portion distilled below 160°, only about 6 grams passing over between 210' and 230'. The latter portion, on refractionation, passed over between 218' and 222' as a colourless oil, which, on aualpsis, gave the followii~g results. 0*1680 gave 0.3632 CO, and 0.1296 H?O.CI5Hz6O6 requires C= 59-60 ; H = 8-61 per cent. That this substance consisted, in this case also, at all events for the most part, of ethglic isopropylpropanetricarboxylate was proved in the following way. The ethereal salt, on hydrolysis, yielded a tricarboxylic acid which melted at 163', and at slightly higher temperatures decomposed, yielding an acid which, after recrystallisation, melted at 96-95' ; this acid gave an anhydride melting at 53", and an anilic acid melting at 156-158' ; it was, therefore, evidently isopropjlglutaric acid. It is, of course, quite possible that, in this experiment, some cthylic methylisopropylethanetricarboxylate may have been formed, but the quantity present in the product of the reaction can only have been small.C = 58.96 ; H = 8.58. Action of Yheiaoxyethylic Bromide, CsHoO*CH2*CH2Br, on the Sodium Dsrivutive of Ethy lic Dirneth ylpropanetricarboxylate, (COOC,H,),C l3.C (CH,),*CH,*C OOC2Hb. The reason for investigating this reaction haB been mentioned in the introduction to this paper; the experiment was carried out as follows. Sodium (5 grams) was dissolved in absolute alcohol (70 grams) in a Bask connected with a reflux apparatus ; the solution, when nearly cold, was mixed with ethylic dimethylpropnnetricni*boxylak (62OF ACRYLIC ACID, AND OF OLUTARIC ACID. 1501 grams), then phenoxyethylic bromide (45 grams) was added, and the whole gradually heated to boiling on a water bath. No action appeared to take place until the temperature had risen to about 50', then sodium bromide began to separate rapidly, and after heating to boiling for four hours the liquid had a neutral reaction.Water was now added, the oily product extracted four times with ether, the ethereal solution well washed with water, dried over calcium chloride, and evaporated, when 88 grams of a very slightly coloured oil was obtained ; t h i s was not analysed but directly converted into the corre- sponding acid by hydrolysis. %'or this purpose, the oil was heated for four hours in a reflux apparatus wiih potash (80 grams), dissolved in pure methylic alcohol, the bulk of the alcohol was then distilled off, water added, and the neutral oil (phenoxyethyl ethyl ether, C6H50*CH2*CH2*OC2H5, see p. 1503) which separated was extracted with ether ; the aqueous solution was then evaporated on a water bath until quite free from alcohol, and the cold, moderately concentrated solution acidified with hydro- chloric acid.This caused the precipitation of a viscous oil, which, however, on adding ice and shaking well, solidified in the course of half an hour, to a hard, ochre-coloured mass. In order to purify it, the crude substance was ground up with water, well washed by means of the pump, dissolved i n dilute sodium carbonate, and the brown solution heated on a water bath with purified animal charcoal for an hour ; after filtration, the liquid was very much lighter coloured, and, on the addition of hydrochloric acid, gave an almost colourless, oily pre- cipitate, which, however, very rapidly solidified. The solid acid was collected, washed with water, left in contact with porous porcelain for a few days, and then purified by recrystallisation from dilute acetic acid ; it was thus obtained iii the form of colourless prisms, which, on analysis, gave the following numbers.I. 0.1106 gave 0,2676 GO2 and 0.0626 HzO. C = 65.99 ; H = 6.33. IT. 0.1392 ,, 0.3381 ,, ,, 0.0750 ,, C = 66.23 ; H = 5.98. (C6H5*O*CH2*CH2)zC(COOH)2 requires C = 66.28; H = 5.81 p.c. This acid melted at about 150-152' with decomposition, and was found, on examination, to be diphenoxyethylmalonic acid, identical with the acid which was subsequently prepared by the action of phenoxyethylic bromide on the sodium derivative of ethylic malonate, and is described i n a previous paper (Bentley, Haworth, and Perkin, this vol., 169).Sults of Di~he?aoxyethylnialonic m i d . These have not been previously described. The siZver saM, ( C6H50*CH,*CH,)C(COOAg)2, was obiained as a curdy, white precipitate on adding an excess of silver nitrate to1502 PERKIN : SOME DERIVATIVES OF PROPIONIC ACID, the slightly alkaline solution of the ammonium salt of the acid. It was collected, well washed with water, dried on a porous plate over sulphuric acid and t8hen for a short time in the water oven. C = 40.09; C,,H,,Ag20s requires C = 40.86; H = 3.22; Ag = 38.71 per cent. Thedilute solution of the ammoilium salt of this acid shows the 0.1981 gave 0.2907 C02, 0.0621 H,O, and 0.0759 Ag. H = 3.45; Ag = 38.31. following behaviour wit11 reagents. Calcium Chloride.-A heavy, white, amorphous precipitate.H n ~ i z ~ n ~ Chloride.-A white, amorphous precipitate, which, on boiling, apparently becomes crystalline. Copper XuZphate.-A light blue gelatinous precipitate, insoluble in water. Lead Acetate.-A white, gelntinous precipitate, which, on boiling, cakes together to a caseous mass quite insoluble in water. Dip henox yet h y lace tic acid, ( C6HD* O*CH2*C H,) H* C 0 0 H. When diphenoxyethylmalonic acid is heated at 180', it is rapidly decomposed wit,h evolution of carbon dioxide and formation of diphenoxyet,hylacetic acid, the reaction taking place quantitatively, as is shown by the following experiment. 9.0224 grams of the pure dibasic acid, heated in a small flask in an oil bath, lost 1.1574 gram of CO, = 12.83 per cent., whereas accord- ing to the equation { C,H,.O*CH2*CH,),C (COOH),= (C6H6*O*CH,*CH2),CH0COO€€ + Cot, the calculated loss is 12.78 per cent.The residual monobasic acid was dissolved in dilute sodium carbonate, and the solution digested with purified animal charcoal and filtered; the filtrate was then acidified with hydrochloric acid, and the precipitated acid, which at first was oily but which soon solidified t o a hard cake, was washed with water, and purified by I ecrystallisation from dilute alcohol. 0.1264 gave 0.3334 CO, and 0.0751 H20. C = 71.93 ; H = 6.60. (C,H6*O*cH2*CH2)2CH*COOH requires C = 72.00 ; H = 6.67 p. c. It melts at 87-88' and is identical wit,h the acid obtained from the sodium compound of ethylic malonate by the action of phenoxyethylic bromide (Bentley, Haworth, and Perkin, this vol., 169).The follon-- iug salts of this acid, which have not been described, were prepared when the acid was first obtained. The silver salt, (CsH,*O*CH2*CH2),CH*COOAg, obtained on adding silver nit'rate to a slightly alkaline solution of the ammoilium salt of the acid, is a caseous precipitate, which after repeated washingOF ACRYLIC ACID, AND OF GLUTARIC ACID. 1503 with water, becomes quite brittle. It was ground up, washed well with water and then with methylic alcohol, and dried over sulphuric acid. C = On analysis the following results were obtained. I. 0.2480 gave 0.4830 GO2, 0.1068 H,O! and 0.0646 Ag. 53.11 ; H = 4.78 ; Ag = 26.05. IT. 0.1240 gave 0.0326 Ag. The dilute neutral solution of the ammonium salt shows the follow- Ag = 26.45. C,,H,,AgO, requires C = 53.07; H = 4.67; Ag = 26.53 per cent.ing behaviour with reagents. Calcium Chloride.-A white gelatinous Frecipitate, almost insoluble Barium Nitrate.--No precipitate even on boiling. Copper XuZphate.-A light blue, caseous precipitate, which, on Lend acetate.-A white, caseous precipitate, which, on warming in water. boiling, becomes granular. with water, becomes pasty and apparently decomposes. Phenoxyethy l Ethyl Ether, Ce&'O*C H2*CH2*O*C2H5. During the hydrolysis of the product of the action of phexoxy- ethylic bromide on the sodium compound of ethylic dimethylpropane- tr-icarboxylate it was found, as stated on p. 1501, that a considerable quantity of a neutral substance mas formed. The product from several experiments was collected, dissolved in ether, washed with water, dried over calcium chloride, and the ethereal solution eca- poi-ated ; on submitting the oily residue to fractional distillation, the greater portion boiled at 227-229*, and gave the following results on analysis. 0.1.502 gave 0.3974 CO, and 0.1150 H20.C,oH,102 requires C = 72.28 ; H = 8-43 per cent. There can be no doubt that this substance is phenoxyethyl ethyl ether, produced by the action of sodium ethoxide on the phenoxy- ethylic bromide used in the experiments. C6H5*0-CH ,*CH,Br + NaOC,H, = C6E1[5.0.CH,.CH?*OoC?~5 + NaBr. It is a colourless oil possessing a penetrat'ing odour somewhat similar to that of benzyl ethyl ether, C6&,-CB2*O*C2H5. C = 78-16 ; H = 8.50.1504 PERKIN : SOME DERJYATIVES OF PROPIONIC ACID, Action of Pheizoxyethylic Bromide, C6Hs*O*CH2GH,Br, on the Sadiun~ Foimation of Deyivative of Ethylic Isopropyl@-opanetricarboxylate.Pheizoq et hy lisoprop y lpropanetricarbox y lic acid, (COOH),? ---CHa*$JH*COOH CH2*CH2*O*Cp,H5 CH (CH,), In carrying out this experiment, 1.2 gram of sodium was dissolved in 15 grams of absolnte alcohol, and, after cooling well, 15 grams of ethylic isopropylpropanetricarboxylate was added ; the yellow solu- tion thus produced was mixed with 11 grams of phenoxyethylic bromide, and the whole heated in a reffnx apparatus on the water bath; at first very little action appeared to take place, but after a time the liquid became suddenly cloudy and quantitiee of sodium bromide separated rapidly. After heating for 10 hours to boiling, the product, which was still alkaline, was mixed with water, and extracted five times with ether; the ethereal solution was washed well, dried over calciuni chloride, and evaporated, when 22 grams of a yellow oil were ob- tained, which did not solidify after standing over sulphnric acid in a vacuum for two days.This oil, on examination, proved to be a mixture ; it was therefore not analysed but converted into the corresponding acids, by boiling for two hours with methyl alcoholic potash (20 grams). The alkaline product was evaporated until free from alcohol, extracted with ether to remove any neutral oil (phenoxyethyl ethyl ether), again evapo- rated, the residue dissolved-in water, and, after cooling well, acidified with dilute hydrochloric acid. The yellowish scmi-solid mass which was thus precipitated soon became quite solid, especially after adding ice and shaking well; it was collected, ground up with water, and washed with the aid of the pump, the mother liquors being preserved for subsequent investigation (see below). In order to purify the crude acid thus obtained, it was dissolved in dilute sodium carbonate, digested with purified animal charcoal, filtered, and the filtrate, after cooling with ice, acidified with hydrochloric acid, the whole being stirred during the operation. I n this way an almost colourless precipitate of nearly pme phenoxyethylisopropyl- propanetricarboxylic acid was obtained, which, after washing and drying, resembled starch powder in appearance ; in this condition, i t melted at 178-180° with vigorous evolution of gas. This product was now dissoIved in much pure ether, the ethereal solution evaporated to a small bulk, and allowed to stand in a closed flask, when the pure acid separated in hard, glistening, crystalline crusts ; these crystals were washed with ether, dried at loo", and nnalysed with the following results.OF ACRYLIC ACID, AND OF GLUTARIC ACID. 1505 I. 0.1080 gave 0.2368 CO, and 0*0640 H20. C = 59.80 ; H = 6.58. IT. 0.1032 ,, 0.2286 ,, ,, 0.0630 ,, c = 60.41 ; H = 6-78, C17H120, requires C = 60.36; H = 6.51 per cent. Phenoxyethylisopropylpropunetricurboxylic acid, when heated in a capillary tube, softens at 178" and melts at 179-180° with I-apid decomposition into carbon dioxide and the corresponding dibasic acid. It is readily soluble in alcohol, but only sparingly in benzene, light petroleum, chloroform, and cold water; the finely divided sub- stance dissolves with difficulty in boiling water, and crystallises out again on cooling almost completely in curious nodular masses. The yield of the phenoxy-acid obtained by the above method is only 4-5 grams from 15 grams of ethylic isopropylpropanetricarboxylate, whereas, assuming this ethereal salt to be pure, over 17 grams should have been obtained. One reason for this is the formation of consider- able quantities of phenoxyethyl ethyl ether during the reaction, and thus a portion of the e thylic isopropylpropanetricarboxylate employed takes no part in the decomposition, and remains unchanged in the crude product of the reaction. On hydrolysing this crude pro- ductl, as described above, and precipitating the phenoxy-acid with hydrochloric acid, isopropylpropanetricarboxylic acid remains in the filtrate and in the mother liquors from the purification of this acid, and is easily recovered by neutralising with sodium carbonate, evapor- ating to a small bulk, acidifying, and extracting 10 times with pure ether. After drying over calcium chloride and distilling off the ether, the oily residue was etherified by treatment with alcohol and sulph- uric acid, and the ethereal salt, after -purification by distillation under reduced pressure, was employed in subsequent operations. Ultimately a good yield of phenoxyethylisopropylpropanetricarb- oxylic acid may be obtained in this way ; but the preparation of this acid is, nevertheless, a very tedious one, many weeks being required in preparing it-even in small quantities. Phertoxyethylisopropylglutaric acid, COOH*~H-CH2-FH*COOH CH,*CH,*O*C,H, CH(CH,), - When phenoxyethylisopropylpropanetricarboxylic acid is heated at 180-19U0, it rapidly loses carbon dioxide, and, apparently also, water vapour, and is converted into a colourless oil which, on cooling, does not solidify, even on long standing, and may possibly consist of the anhydride of the dibasic acid. It was dissolved in boiling dilute sodium carbonate, the solution filtered, acidified, and extracted with pure ether, the ethereal solution dried over calcium chloride, evaporated at a low temperature, and the residual oil allowed to stand for two VOL. LXIX. 5 11506 HEINKE AND PERKIN : ETHYLIC &IODOPROPIONATE days, when it had almost completely solidified. Considerable diffi- culty was experienced in endeavouring to recrystallise the acid, but ultimately this was accomplished by dissolving the crude substance i n a large quantity of light petroleum (b. p. 100-120°), boiling with animal charcoal, filtering, and allowing the solution to stand for some days exposed to the a i r ; nodular crystals then separated, which, after washing with light petroleum (b. p. 40-45'), gave the following numbers on analysis. 0.1317 gave 0.3161 CO, and 0.0899 H,O. C = 65.43; H = 7.50. 0.1431 ,, 0.3415 ,) ,, 0.0969 ,, C = 65.10; H = 7.51. C16H2205 requires C = 65.30; H = 7.49 per cent. Phenoxyethylisopropylglutaric acid melts at about 90-93O ; it is readily soluble in alcohol and ether, but almost insoluble in water. When heated for some time in a water bath, it is converted into an oil which, on cooling, sets to a transparent jelly; this does not ciyitallise, even on mbbing with a crystal of the pure acid, and, therefore, may possibly be the anhydride of the acid, especially as i t dissolves in cold sodium carbonate with difficulty.

ISSN:0368-1645    

DOI:10.1039/CT8966901457

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

1506 HEINKE AND PERKIN z ETHYLIC &IODOPROPIONATE XCV1.-Action of Ethylic P-Iodopropionate 032 the Sadium Derivative. o f Ethylic Isopj-op ylrnalonate. By J. L. HEINKE and W. H. PERKIN, jun. THESE experiments which were instituted, as explained in the intro- duction to the preceding paper, with the object of obtaining addi- tiocal evidence of the constitution of isopropylglutaric acid, were conducted as follows. Sodium (6 grams) was dissolved in absolute alcohol (75 grams), the solution cooled, and very carefully puriJed ethylic isopropyl- maloiiate (55 grams) and ethylic P-iodopropionate (50 grams) were add.ed, when a somewhat energetic action set in, the mixture becoming quife hot. As soon as the action had subsided, the mixture was heated for four hours on a water bath, in a reflux apparatus, water WRS then added, the oily product extracted three times with ether, the ethereal solution washed well with water containing a little sulphurous acid, to remove traces of iodine, dried over calcium chloride, evaporated, and the residual oil fractionated under rediiced pressure (100 mm.).Between 150" and 210°, about 20 grams came over, the thermo- meter thcn rose rapidly to 220°, most of the residue distilling at 225-235", and this portion, on refractionation, distilled almost con-AND DERIVATIVE OF ETHTLIC ISOPROPYLMALONATE. 1507 stantly at 228-230" (100 mm.) as a thick, colourless oil, which, on analysis, gave the following numbers. 0.1604 gave 0.3490 CO, and 0.1236 H,O. C = 59.34; H = 8.56. 0.1444 ,, 0.3 159 ,, ,, 0.11 23 ,, C = 59.64; H = 8.65.T his e t h y lic a -isopropylpro23ane-aaol,- tricar box y 1 c te, C,,H,06 requires C = 59-60; H = 8.61 per cent. ( C 00 C,H,) 2C (C3H7) *C H,*CH,*C00 CzHj, is isomeric with the ethereal salt, (COOC,H,)2*CH.CH,*CH (C3H7) *COOCZHs, described i n the preceding paper, and obtained by the action of ethylic ol-bromotrimethylpropionate on the sodium derivative of ethylic malonate, or by condensing ethylic malonate with ethylic isopropylacrylate. Both of these ethereal salts are thick, colourless oils, the former boiling apparently rather higher than the latter. Hydrolysis of Ethylic a- Isopropy lpropane-aau,-triearboxylate. Forma- tio )t of a - Isopr op y .?propane -aa aI - trica r boz y lic acid, and of Isopropy lg 1% - tayic acid. The hydrolysis o € et hylic isopropyl propanetricarboxylate was carried out by boiling the pure substance in a reflnx apparatus with twice the calculated quantity of alcoholic potash for four hours ; the product was mixed with water, evaporated on a water bath till free from alcohol, acidified, and extracted 10 times with pure ether. The ethereal solntion was dried over calcium chloride and evaporated at a low temperature, when an oily acid was obtained which did not crystallise, even when left for some days over sulphuric acid in a vacuum.The analysis gave numbers indicating that the substance consisted of nearly pure a-isopropylpropane-aml-tricarboxylic acid. 0.1423 gave 0.2607 CO, and 0.0810 H20. C9Hlr0, requires C = 49.54; H = 6.41 per cent. This acid differs from its isomeride, described in the preceding paper, in that, when its solution i n water is saturated with hydrogen chloride, the acid does not separate in a crystalline form, and it has, so far, not been possible to obtain the substance in a crystalline state by treatment with various solvents.When heated at 200°, the tribasic acid is decomposed with evolution of carbon dioxide and formation of isopropylglu taric acid ; this was best purified as follows :-The crude acid was digested with acetic anhydride, and then converted into its anhydride; this was frac- tionated under reduced pressure, when almost the whole distilled a t 217-2.22" (100 mm.) as a colourless oil which rapidly solidified on C = 49.95 ; H = 6.33. 5 1 21508 HEINKE AND PERKIN : ETHYLIC P-IODOPROPIONATE standing.The crystals were spread on porous porcelain until free from oily mother liquor, and the residual, colourless, crystalline mass recrystallised from light petroleum. 0.1762 gave 0.3969 CO, and 0.1210 H20. C8H120, requires C = 61.54; H = 7.68 per cent. This anhydride melts at 53-54', and crystallises from light petroleum in the same characteristic woolly masses as the isopropyl- glutaric anhydride described in the previous papel-. When treated with aniline in benzene solution, it yields isopropylglutaranilic acid {m. p. 158'), which was analysed with the following result. C = 61.43; H = 7 6 3 0.2966 gave 11 C.C. moist nitrogen at 15' and 955 mm. N = 5.65. Cl,H,,NOs requires N = 5.62 per cent. Lastly, if the anhydride be dissolved in boiling water, the solution .concentrated, saturated with hydrogen chloride, and allowed to stand, hard, colonrless crystals of isopropylglutaric acid separate, which melt at 9&95', and resemble in all respects the crystals of isopropyl- glutaric acid obtained in the manner described in the previous paper.0,1470 gave 0.2963 CO, and 0.1067 H20. CeH,,O4 requires C = 55.17; H = 8.04 per cent. While these experiments were in progress and nearly completed, we heard from Professor Auwers that he had instituted similar .experiments in conjunction with Mr. A. W. Titherley." These chemists studied the action of ethylic P-iodopropionate on the sodium derivative of ethylic isopropylmalonate, and thus obtained an ethereal salt boiling ai; 19i" (33 mm.), which, although not analysed, was obviously identical with the ethylic a-isoproyylpro- pane-aaa,-tricarboxylats obtained by us, and which distilled, as stated above, at 228-230" (100 mm.).This ethereal salt was then hydrolysed by boiling with hydro- chloric acid, and thus converted into a remarkably stable crystal- line diethylic salt of the formula (m. p. 68-6S0), which appears to resist the further action of the acid; when boiled with alcoholic soda, however, it is hydrolysed, with formation of a syrupy acid, wbich evidently consists of not quite pure isopropylglutaric acid. As soon aa Professor Auwers heard that we were investigating this subject and had already -obtained pure isopropylglutaric acid, he did not continue his experi- ments, but kindly left the completion of the research to us.* The results of these experiments have since been published in the Annalen, 1896,292, 217. C = 55.07 ; H = 7-93. (C 00 C2H5) 2C (CZH,) *CH,*CH2*COOH9AND DERIVATIVE OF ETHYLIC ISOPROPYLMALONATE. 1509 Pflztane-a y p , - t etracarboxy Zic acid, (CO OH) 2C ( CH2*CH2*C0 OH),. In our first experiments on the action of ethylic P-iodopropionate on the sodium derivative of ethylic isoyropylmalonate, a sample of the latter was employed which boiled a t 209-211', and which, although it had been carefully prepared, must evidently, from the results subsequently obtained, hare contained some unchanged ethylic malo- nate. This fraction was treated with sodium and ethylic P-iodo- propionate, as described on p. 1506, and the product distilled undey reduced pressure (30 mm.), when, after the ethylic isopropylpro- panetricarboxylate had passed over, a considerable fraction was obtained, boiling at 230-235'. After again fractionating, this oil gave the following results on analysis. 0.1411 gave 0.2957 COz and 0.1019 H,O.C17H2BOA requires C = 56.67; H = 7-78 per cent. The further examination of this substance showed that it was ethylic pentane-aVya,- tetracarboxylate, identical with the compound obtained by Emery (Bey., 1891, 24, 282) by treating the sodium compound of ct hylic nialonate with e thy lic P-bromopropionate. C = 57.13 ; H = 8.03. (COOC2H5)2CNa2 + 2CH,BrGH&OOC2H5 = Emery gives the boiling point of his ethereal salt as 215' (13 mm.). From the ethereal salt, the corresponding tetracarboxylic acid, which is not described by Emery, niay be obtained in the following way.It is hydrolysed by boiling with an excess of alcoholic potash for two- hoars in a reflux apparatus, the solution mixed with water, boiled until free from alcohol, evaporated to a small bulk, acidified, and extracte8 at least 30 times with pure ether, as the acid is only sparingly soluble in ether and very difficult to extract. After drying tho ethereal aolu- tion over calcium chloride and evaporating to a small bulk, crystal- line crusts are deposited on standing; these were collected, washed with ether, dissolved in a very little water, and the solution saturated with hydrogen chloride, when almost the whole of the acid separated as a colourless, sandy powder, which gave the following results on analysis. (COO C2H,),C ( CH2G H2*COOC2H5), + 2NaBr.0.1321 gave 0.2112 CO, and 0.0594 H20. C9Hn0, requires C = 43.55 ; H = 4.84 per cent. Pentalze-a.ly~.,-tetracar~oxylic acid, when heated in a capillary tube, decomposes rapidly at about 185-187' with vigorous evolution of gas, and form a tion of pentane-z ya,- tricarboxylic acid. C = 43-61 ; H = 4.99.1510 BENTLEY AND PERKIN ON v-ACETOBUTYRIC ACID. Pentane-a~a,-tricarboxyZic acid, C 0 OHGH (C H2*CH2*C: 0 OH) 2. This acid was prepared by heating the corresponding tetracarb- osylic acid at 200" until the evolation of carbon dioxide had ceased. The syrupy residue was diseolved in hot water, and the solution, after cooling, saturated with hydrogen chloride, but no crystaliisation took place even on long standing ; when, however, the solution was placed over solid potash in a vacuum desiccator, beautiful colourless prisms separated after some days; these were collected, dried at 90°, and anal y sed. C = 47.03 ; H = 6.29. 11. 0.1431 ,, 0.2478 ,, ,, 0.0768 ,, C = 47.23; H = 5.97. CeH,,Os requires C = 47.06; H = 5-88 per cent. Pentane-acya,-tricarboxylic acid melts a t 114-115' with slight Emery (Bey., 1891, 24, 284) gives the melting I. 01785 gave 0.3078 COz and O*lOOL HzO. previous softening. point a t 106-10i".

ISSN:0368-1645    

DOI:10.1039/CT8966901506

出版商:RSC    

年代:1896

数据来源: RSC

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1510 BENTLEY AND PERKIN ON v-ACETOBUTYRIC ACID. XCVT1.-Note on y-Acetobuty-ic acid, CH;CO.CH;CH;CH;COOH. By W. H. BENTLEY and W. H. PERKIN, jun. DURING the course of an investigation on sulphocamphylic acid, the results of which, it is hoped, will soon be ready for publication, a ketonic acid was obtained, which had many properties in common with, and was for a long time thought to be, yacetobutyric acid. This acid has already been prepared by Wolff (Annalen, 1883, 216, 129) from ethylic rtcetylglutarate, by hydrolysis with dilute hydro- chloric acid, CH3*CO*CH(COOC2H,)*CH2*CH2*COOC2Hs 4- 2H2O = CH,*CO*CH~*CHz*CRz*COOH + CO2 + 2C2HS*OH, and by Lipp (Bey., 1885, 18, 3251), by the oxidation of acetobutylic alcohol, CR3*C 0.C Hz*C H2.C Hz* CH2*OH, with potassium dichromate and snlphuric acid.It is a colourless oil, which boils at 274-275" with siight decom- position ; it solidifies in a freezing mixture with difficulty, the crys- talline substance melting at 13O, whilst with water i t yields st crystalline hydrate, CH3.C(OH)2*CH2*CH&'H2*COOH, which melts at 35-36O. As these properties of acetobutyric acid proved to be altogether insufficient for the purposes of comparison with thc acid obtained from sulphocamphylic acid, we have prepared considerable qwmtities of the former and carefully examined two new derivatives,BENTLEY AND PERKIN ON ~~-ACETOBUTYRIC ACID. 1511 namely, the oxime, CH& (NOH)*CH2~CB2*CR2*COOH (m. p. 104- CH,*CH2*CH2*COOH 105O), and the semicarbazone, CH3*'C<N,NH,C0.NH2 (ma P. 173-174'), which are well characterised, and will serve in future for the identification of the acid.A t the same time, we have introduced some improvements into the preparation of this acid, and hope that the followicg short account will be of value to subsequent investigators. Pyeparation of y- Acetobuty ric acid, CH,*CO*CH,*CH2*CH2-COOH. The method which we employed in the preparation of this acid was similar to that recommended by Wolff and mentioned above, namely, by the hydrolysis of ethylic acetoglutarate. Sodium (3.4 grams) is dissolved in alcohol (45 grams), and to the well-cooled solution, first ethylic acetoacetate (19 grams) and then ethylic P-iodopropionate (33 grams) are added. The reaction takes place readily, the mix- ture getting quite hot; after standing for half an hour, the whole is heated on a water bath for two hours, water is then added, and the oily product extracted with ether.The ethereal solution after being well washed with water containing a little sulphurous acid to remove traces of iodine, is dried over calcium chloride, evaporated, and the oily residue, which weighs about 26 grams, is purified by distillation under reduced pressure (50 mm.). The crude substance commences to boil at 130°, but, after a few drops have passed orer, the tempera- ture rises rapidly to 190°, and nearly the whole passes over between this and 200°, a small quantity only of a residue of high boiling point remaining in the retort. Pure ethylic acetylglutarate is a colourless oil, which boils at 195-197' (50 mm.); on analysis, it gave the €0110 wing result. 0.1180 gave 0.2478 COz and 0.0845 HzO.C = 57.27 ; H = 7-94, CllH1806 requires C = 57.39 ; H = 7.83 per cent. It is best to distil this ethereal salt under reduced pressure, as it is then readily obtained pure, whereas, if distilled at the ordinary pres- anre, as recommended by Wislicenus and Limpach, it decomposes somewhat, owing to the high temperature at which it boils (271-272'). In order to obtain acetobutyric acid, the fraction of the ethereal salt distilling at 190--200° (50 mm.) is boiled in a reflax apparatus with 5 vols. of dilute hydrochloric acid (1 vol. of concentrated acid to 2 vols. of water). The oily layer rapidly disappears with evolution of carbon dioxide, and hydrolysis is complete after five hours, allhough Wolff recommends boiling for 8-10 hours. I n order to isolate the product, Wolff fractionated the hydrochloric acid liquid direct, but thir always causes considerable decomposition of the acetobntyric acid,1512 BENTLEY AND PERRIN ON v-ACETOBUTPRIC ACID.and we found that a much better result was obtained by proceeding as follows. The acid liquid, while still warm, is saturated with ammonium sulphate, and the acetobutyric acid, nearly the whole of which separates on the surface as an oily liquid, is extracted six times with ether. The ethereal solution is dried over calcium chloride, evaporated, and the residual, almost colourless oil is fractionated under reduced pressure, when almost the whole distils at 195--200° (65 mm.), the yield being about 85 per cent. of the theoretical.0,1322 gave 0.2676 C02 and 0.0926 H,O. C6HloOs requires C = 55.38 ; H = 7.69 per cent. The acetobutyric acid prepared in this may was a perfectly colour- less, moderately thick oil, which when mixed with a little water rapidly solidified to colourleas crystals of the hydrate C = 55.20 ; H = 7.79. CH3.C (OH)2*CHz*CH2*CH2*COOH. Oxidation with Nitric acid.-A few grams of the pure acid were gently heated with nitric acid (sp. gr. 1.2) in a reflux apparatus, when oxidation SOOLL commenced, red fumes being copiously evolved. After boiling for about two hours, the product was diluted with water, evaporated to dr-yness on the water bath, and the crystal- line residue, after being left in contttct with porous porcelain until colourless, was recrystallised from concentrated hydrochloric acid.The colourlesfi crystals which separated melted at 180-183", and were found to consist of pure szcccinic acid, the oxidation having taken place at the epCH2 group marked *, CH,* C0.C kz*CH2*CH2*C OOH. It was at first thought probable that the reaction might take place in snch a way that glutaric acid mould be produced ; probably this acid is formed when bromine in presence of potash is used as the oxidising agent, as in this case quantities of tetrabromomethane, CBr4, are deposited in a crystalline condition. Oxirne of Acetobu.tyric acid, C H3*C (NOH). CH2*CH,*CHz*C0 OH. This was prepared by dissolving hydroxylamine hydrochloride (5 grams) in a small quantity of water, adding acetobutgric acid (6 grams) and then, after cooling, mixing the clear solution with a concentrated solution of potash (7 grams).After 20 hours, the liquid was acidified, saturated with ammonium sulphate, and extracted at least 25 times with ether. The ethereal solution was dried over calcium chloride, evaporated, and the solid residue purified by recry stallisation from benzene. 0,1563 gave 13 C.C. moist nitrogen at 18" and 760 mm. N = 9.60. CsH,,N03 requires N = 9.65 per cent.ACTION OF CHLOROFORM, ETC., ON BlEThMIDOBENZOIC ACID. 151 3 The oxime of acetobutyric acid crystallises from benzene in colour- less prisms, and melts at 104-105°. It, is readily soluble in alcohol, water, and hot benzene, but only sparingly in ether, light petroleum, or cold benzene. Acetobut yric acid semicm?mzone, CH3*( cH2* H2' co H. N-NH-C O*NH2 In order to prepare this substance, semicarbazide hydrochloride was dissolved in a very little warm water, the solution mixed with an equal quantity of hot concentrated sodium acetate solution, the acetobutyric acid added, and the clear liquid heated to boiling for a few seconds ; on cooling, the semicarbazone rapidly separated in crystals, which, after standing over night, were collected, washed, and purified by recry stallisation from a little hot water. 0.1016 gave 20 c.c moist nitrogen at 19' and 758 mm. C7H,3N30, requires N = 22.46 per cent. N = 22.56. Acetobutyric acid semicarbazone, when heated in a capillary tube, softens at 168O, and melts and d.ecomposes at 173-174'. It is readily soluble in hot water, and crystallises from the solution on cooling in colourless, glistening needles.

ISSN:0368-1645    

DOI:10.1039/CT8966901510

出版商:RSC    

年代:1896

数据来源: RSC

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ACTION OF CHLOROFORM, ETC., ON BlEThMIDOBENZOIC ACID. 151 3 XCVI 11. -A c t ion of Chloroform ai 1 d Pot ussium .Hydroxide on, l%?etarnidobenxoic acid. By WALTER JOHN ELLIOTT, M.A. AS the action of chloroform and potash on amido-acids of the aro- matic series had not been investigated, it seemed of interest to ascertain whether the presence of the carboxyl group would cause any vayiation in their ordinary action on compounds containing the amido-group, especially as Dr. Ruhemann and the author have shown that, in the case of phenylhydrazine, the reaction is not normal, the substances formed not being isonitriles (Ruhemann and Elliott, Trans., 1888, 53, 850; Ruhemann, Trans., 1889, 55, 242). In the early experiments, a solution of potash in alcohol was used, but a solution in water was afterwards found to give a better yield.5 grams of metamidobeneoic acid dissolved i n spirit were added to 8 solution of 15 grams of potash also dissolved in spirit., and the mix- ture was heated on a water bath in a flask furnished with a reflus condenser; 8 grams of chloroform were then carefully added, and the whole boiled for some time. On cooling, diluting considerably with water, and acidifying with dilute hydrochloric acid, a yellow, amorphous precipitate was thrown down after a time; in some of1514 ELLIOTT: ACTION OF CHLOROFORM AND the experiments, a slight isonitrile odour was detected before acidi- fying. After collecting and washing the product, attempts were made to purify it by crystallisation, but no solvent for i t has yet been found ; it is insoluhle in water, alcohol, ether, chloroform, benzene, petroleum, acetic acid, and acetone ; consequentl;p, its purification has been a matter of great difficulty, increased by the fact that it does not melt below 300°, arid darkens and decomposes above that tern- peratwe.It has, however, acid properties, dissolving in alkalis and in sodium carbonate solution, conseqnently an attempt was made to purify i t by dissolving i t in sodium carbonate Bolution, boiling with animal charcoal, and acidifying, but no precipitate was thrown down, and, on shaking with ether, nothing was removed from the solution. The substance must, therefore, be decomposed by hot alkaline solu- tions ; it was found, however, t o be reprecipitated by acids from cold alkaline solutions, and t h i s method of piirificntion was tried.After washing the reprecipitated substance, it was dried a t ZOOo and analysed. Since the substance does iiot melb, the relative purity of different specimens could only be determined by analysis. The numbers I, 11, and III were obtained by analysis of the repro- cipitated substance, the crude product (after washing with hot water and hot alcohol) giving the results I V and V. I. 11. 111. IV. V. Sldehyde. Carbon .. .. .. .. 57.4 56.66 - 55.4 55-72 58.18 Hydrogen . . .. . . 4.3 4.48 - 5-02 5.13 4.24 - 8.16 - - 8.48 Nitrogen . . . . . . . - As the results of analysis given above show that the percentage of carbon is less than in metamidobenzoic acid itself, the substance cannot be an isonitrile; but it led me to examine the reactions of the product with Fehling’s solution and with phenylhydrazine, with a view of ascertainirig whetber it was an aldehyde or allied compound.A compound having the composition NH,*C6H3( COOH)*COH would have the percentage composition given above in the last column, headed “ Aldehyde ” ; these numbers are in fairly close agreement with the results of analysis. B’ehliug’s solution is readily reduced by it on heating, and almost decolorised even at the ordinary temperature. When suspended in dcohol and treated with a quantity of phenylhydrazine calculated on the basis of the aldehyde formula, the Substance dissolves slowly a t ordinary temperatures, and readily on heating, yielding a deep red solution from which red crystals are precipitated on the addition of water. These reactions indicate that the product is an aldehyde or a compound allied to an aldehyde.In order to obtain further evidence of the aldehyde nature of thePOTASSIUM EYDROXIDE ON METAMIDOBENZOIC ACID. 151 5 product, an aqueous solution was substituted for the alcoholic solu- t,ion of potash, in fact the ordinary method for the preparation of hydroxy-aldehydes from phenols was used ; this was found to give a far better yield. 10 grams of the acid were dissolved i t 1 a solution of 20 grams of potash in about PO0 C.C. of water, 14 grams of chloroform gradually added, and the whole boiled for about three quarters of an hour; the solution was then boiled with animal charcoal for a short time, filtered, cooled, acidi6ed with acetic acid, and left for five or six hours, when about 6 grams of the crude product were deposited.As all other methods of purification had failed, fractional pre- cipitation from the potash solution was tried. The solution acidified with acetic acid was allowed to remain for two hours, filtered from the precipitate which had formed, and again allowed to stand for several hours. The precipitate then formed was well washed with warm water, and dried in il vacuum. Theory for r--J-- 7 CSHjNOP I. 11. 111. Carbon ........ 58.18 57.80 58.11 - Hydrogen. ..... 4.24 5.02 4.7’4 - Nitrogen ....... 8.48 - - 8-36 Found. The substance, therefore, has the empirical formula, CeH,NO,. With the ammoniacal solution of the acid, silver nitrate gives a jellowish precipitate, which readily decomposes.The barium salt was then prepared by adding barium chloride to a neutral solution of the acid in ammonia, the yellow precipitate was collected, washed with water, and dried in a vacuum. On analysis i t was found to contain ‘29.97 per cent. of barium, theory requiring 29.46 per cent. for a salt of thc formula (C8H,N03),Bn. Since the acid was decomposed when boiled with alkalis, it seemed possible that it might also decompose when boiIed with water. 5 grams of the pure acid, when boiled for some time with water gradually dissolved, yielding a clear yellow solution, from which, on cooling, clusters of yellow crystals were deposited ; more of the sub- stance being obtained on shaking the mother liquors with ether, and crystallising the residue left on distilling off the ether.The crystals resembled metamidobenzoic acid in appearance, and melted at the same temperature (174”) ; this was confirmed hy the result of an analysis. Theory for NH2.C6H,.COOH. Fouud. Nitrogen.. ........ 10.21 10.4 Hence on boiling with water metamidobonzoic acid is formed. The fact that a solution of the acid in an alkali, after being boiled and1516 ELLIOTT: ACTION OF CHLOROFORM AND acidified, gave nothing when shaken with ether, is due to the met- amidobenzoic acid formed having combined with the mineral acid to give a salt insoluble in ether. The Pherbylhydrazine Compourtd. Owing to the small yield of this compound, and the fact that it is not very stable, the examination is incomplete, but enough infor- mation has been obtained to wawant a suggestion as to its constitu- tion.Five grams of the pure acid were suspended in alcohol, 3.5 grams of phenylhydrazine added, and the mixture gently heated until solu- tion was complete. After filtering, water was added, and the red precipitate collected and purified by several recrystallisations from dilute alcohol or benzene. It crystallises from alcohol in red needles, which soften and decompose slightly when heated for any length of time at looo, hence the substance should be dried i n a vacuum, The pure dry product melts at 116O, and decomposes with some vigour a t a higher temperature. It is soluble in alcohol, ether, and benzene, and slightly so in water. Found. 7 Theory for --J--- C14H13N4* I. Ir. III. IT. Carbon . . . . , . 71.18 70.75 70.72 - - Hydrogen .. . . 5.08 5.41 5.28 - A Nitrogen . . . . . 23.73 - - 24-11 24.07 This substance, therefore, has the empirical formula C,H,N2, and contains no oxygen. When treated with hydrochloric acid, a dark coloured product is obtained which is easily decomposed by washing with water, yielding the original compound ; it is, however, slightly soluble in the acid, forming a crimson solution. The red compound appears to have, therefore, feeble basic properties ; with dilute sulphuric acid also, it forms a dark coloured product, decomposed by water; strong sulphuric acid dissolves i t with a deep bluish-green coloration. The alcoholic solution dyes a deep yellow, which is turned crimson by acids, but the latter colour is destroyed by water. These facts are accounted for if the substance is considered to be a disazo-compound, with the following formula : and another reason for this formula is given later. In order to ascertain whether any other product was obtained by the action of phenylhydrazine, the original filtrate from the red com- pound was diluted with more water and shaken with ether, and the ether distilled off, The residue, which conkained phenylhydrazine, was crystallised from alcohol and the product purified by several CsK5*N:N*CH:CH*N:N*CsH, ;POTASSIUM HYDROXIDE ON METAMIDOBENZOIC ACID.15 17 recrystallisations from alcohol and from water; it then melted at 173", and, on analysis, was found to contain 10.20 per cent. of nitrogen ; it is, therefore, metamiilobenxoic acid. No other com- pound could be isolated.An attempt was also made to obtain a hydrazone in the usual way, but without result. When the barium salt is suspended in alcohol and heated with phenylhydmzine, the solution becomes deep red, and, on filtering, and adciing water to the filtrate, a red substance is precipitated which has all the properties of the red crystals mentioned above ; the quantity obtained, however, was insufficient for analysis, the yield being small. Conclusion. The results of analysis of the acid formed by the action of chloro- form and potash on metamidobenzoic acid point to the formula CeNH703, but, unlike the aldehydes, it forms no condensation product with strong ammonia solution, and no compound with sodium hydro- gen sulphite solution; moreover, it is insoluble in a,ll solvents. With phenylhydrazine, it yields no hydrazone, but only metamido- benzoic acid and an azo-compound of the formula Cl4Hl2N4, and, when boiled with water and alkalis, it decomposes, yielding meta- midobenzoic acid.These reactions are explained if the following constitution is assigned to this compound :-c7NH602*CH( oH)*co*c7NH60z, that is, diamidodicarboxybenzoh. This constitution will explain the ease with which the compound decomposes. When boiled with water, i t is oxidised, giving metamidobenzoic acid and carbon dioxide. A similar reaction takes place when the compound is boiled with alkalis, With phenyl hydrazine, an osazone is probably first formed according t o the following equation : 2H20 + az, but the hydrogen instead of reducing the phenylhydrazine, as is usually the case, reacts on the osazone and sets free metamidobenzoic acid ; at the same time, a molecular transformation takes place with the formation of a disazo-compound of the formula CeH,*N:N*CH:CH*N:N*C~H~. A similar molecular transformation takes place when phenylhydr- azine acts on the naphthaquinones, azo-compounds being formed instead of hydraxon es.1518 JOKETT ON ATISINE, The react,ions between chloroform, aqueous potash, and various other aromatic compounds, such as phenylhjdrazine and metanitro- benzoic acid, are now being investigated, and I hope to be able to communicate the results t o the Society in a short time. My thanks are due to Mr. F. Beames, R.Sc., for help rendered during the courss of this research. !The G?*amnnr ,School, BristoZ.

ISSN:0368-1645    

DOI:10.1039/CT8966901513

出版商:RSC    

年代:1896

数据来源: RSC

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1518 JOKETT ON ATISINE, XCIX.-Cont~.i~utio.lis to ouq' Knowledge of the Aconite Alkaloids. Part XIII. On Atisine, the Alkaloid o f Aconitum heterophyllum. By HOOPER ALBERT DICKIMON JOWETT, L).Sc. Lond., Research Fellow of the Pharmaceutical Society. AMONGST the many species of Aconitum known to botanists, t<here is one-Aconitzcm hetem@ylZum-which especially attracts attention, because it is not poisonous. I n this respect it differs from the other species of Aconitum which have been chemically examined. The roots of this plant are sold in the Indian bazaars as utis, or atees, and have long been used in India on account of their medicinal value, b u t very little is known concerning the chemical constituents of the root. I n 1873, Broughton (Blue Book, h'ast India Cinchona Cultivation, 1877, 133) isolated an nlkalojid from the roots of t,he plant, to which 'he gave the name atisine, aid proposed for it the formula C46H,,N,0,. The nlkaloi'd was only obtained as a n amorphous varnish, yielding, however, a crystalline sulphate and hydrochloride.The platini- chloride was also prepared, and the formula above given was deduced from the analyses of this salt, which, however, have not been published. Tn 1679, Wasowicz (Arch. Pliarm., 214, 193) isolated the same alkaloi'd from the roots of the plant, and also aconitic acid. Hc adopted Broughton's formula for atisine with very slight! modifica- tion, and prepared the halojid salts in the crystalline condition. The hydriodide was found to be only sparingly soluble in cold water, arid could thus be easily purified by recrystallisation ; on analysis, results were obtained corresponding with the formula, CP~H,,N~O~,HI, H20.In 1879, Dr. Alder Wright (Year Book of Phamaacy, 1879, 422) proposed for atisine the formula, C22H,IN02, based on a single ana- lysis of the amorphous aurichloride, the quantity at his disposal being too small for further examination.THE ALKALOID OF ACONLTUM HETEROPHYLLUM. 1519 In the course of the investigation described i n this paper, the properties of the base and its salts have been carefully determined. A satisfactory method has been devised for the extraction of the roots and the preparation of pure material, and the presence of aconitic acid, mentioned by Wasowicz, has been confirmed. Extr*actioiL of the Alkaloid fyom the Root, and its PzcriJicatioia.The solvents, previously used to extract the alkaloXdal salts from the aconite roots, hare been chiefly alcohol acidified with 1 per cent. tartaric acid, or more recently amylic alcohol (steam-dist,illed fusel oil). After a number of experiments with different solvents such as light petroleum, ether, alcohol, &c., had been made, it was found that the most satisfactory results were obtained by using a mixture of methylic arid amylic alcohols, in the proportion of three volumes of methylic alcohol to one volume of arnylic alcohol, the commercial wood spirit and fusel oil being employed for this purpose. The advantages of this solvent for the extraction of the roots are (i) the roots are completely extracted in a very short time, and the percolate does not contain very much colonring matter, resin, $c., although more than if amylic alcohol alone were used ; (ii) the percolate can be reduced to a small bulk without very much heating, as the methylic alcohol can be distilled off at a low temperature under diminished pressure, thus prevenhg decomposition of the alkaloid by heat ; (iii) the alcoholic solution thus obtained deposits a large quantity of fat and colouring matter, from which the alcohol containing the alkala'id in solution can be separated by decantation.The alkalo'id can then be extracted by shaking the alcoholic solution with 1 per cent. aqueous sulphuric acid, and following the methods described when amylic alcohol alone is used. This solvent, which has since been successfully employed for the extraction of other species of aconite roots, possesses the advantage of both methylic and amylic alcohols with none of their attendant disadvantages.About 60 lbs. of the root in fine powder were extracted by per- colation with t'lie above medium, and the percolate obtained, which was of a daiak brown colour, was distilled over a water bath, when most of the methylic alcohol, together with a little amylic alcohol, was removed. On standing, the alcoholic solution deposited a large quantity of very dark coloured fat, which was separated by decanta- tion; the solution in amylic alcohol mas then repeatedly shaken with 1 per cent. aqueous sulphuric acid until no more alkaloid was extracted, the acid liquid shaken twice with chloroform to remove aniylic alcohol, and then, after neutralisation, concentrated by evaporation on a water bath.The concentrated solution, which was7 520 JOWETT ON ATISINE, dark coloured, was rendered alkaline by aqueous sodium hydroxide, and then repeatedly shaken with ether or chloroform until no ap- preciable amount of alkalo'id mas any longer extracted. It is not possible, however, by this method to extract the whole of the alkaloid from the aqueous liquid. The ethereal (or chloroform) solution, after being washed once or twice with water, is distilled, and the residue dissolved in dilnte sulphuric acid, using as small an excess as possible. The solution thus obtained is dark brown, and still contains in addition t o the alkaloidal salt, a large quantity of resinous aiid colouriDg matter, which prevents crystallisation when the solution is evaporated, These attendant impurities are best removed by fractionally pre- cipitating the alkaloid with aqueous sodium hydroxide, the first fractions containing nearly the whole of the impurities, whilst the later fractions consist of almost pure alkalo'id ; this fractionation is repeated several times, until the acid solution of the alkaloid is almost colourless.The freshly precipitated alkalo'id, after being col- lected and washed, is suspended in water and dissolved in exactly the right quantity of dilute hydrochloric acid to form a neutral solution of atisine hydrochloride. This, when slowly evaporated on a water bath, yields crystals, which are collected and re-crystallised once 01' twice from water, and then from alcohol ; on adding ether to tho alcoholic solution until there is a faint permanent turbidity, and then setting it aside in a stoppered bottle, fine needle-shaped crystals of the pure hydrochloride are obtained.These are collected and dried in the usual manner. For the extraction of the remaining traces of alkaloid in the different filtrates obtained during fractionation, and in the mother liquor after extraction with ether, a different method is employed. The solution is rendered faintly acid and excess of po tassio-mercuric iodide added, the precipitate thus produced is first thoroughly washed several times by decantation with water, and then suspended in water, and decomposed by passing hydrogen sulphide through the mixture ; the precipitate is then collected, extracted by boiling water until no more is dissolved, and the aqueous extracts mixed and allowed to cool ; on standing, very faintly coloured crystals of atisine hydriodide separate, which may be purified by recry stallisation from hot water.A few crystals can be obtained by concentrating the original filtrate, but owing to the sparing solubility of the salt in cold water, scarcely anything is left in the mother liquors. In this way the whole of the alkaloid is obtained as the sparingly soluble crystalline hydriodide, and the easily soluble hydrochloride, the amount of hydriodide contained in the mother liquor being so small that it may be neglected.THE ALKALOIII OF ACONITUM HETEROPHYLLUM. 1521 The total amount of alkaloyd contained in the root is small, from 0.2 to 0.3 per cent., and no evidence was obtained of the existence of any alkalo'id other than atisine.IdentiJication of Aconitic acid from the Root. As the melting point of the acid obtained by Wasowice did not agree with that recorded for aconitic acid by other observers, I pre- pared the acid from the root, and examined its properties. It was isolated by means of its lead salt, which was then decomposed by hydrogen sulphide, and purified by crystallisation from water until its melting point was constant. It is a white, ci*ystalline substance, very soluble in ether or water, and, when dried at loo', melted and decomposed with effervescence at 191.5' (corr.). Aconitic acid melts, and decomposes with effervescence, at 191'.On analysis, the acid and its silver salt yielded the following data. 0.0382 acid required 12.5 C.C. N/20 soda, 0.0758 silver salt gave 0.0494 Ag. Ag = 65.17. Calculated for CSH606, 13.1 C.C. and 63.45 per cent. silver. The acid is thus proved to be aconitic acid. Composition and Properties of Atisine and its Salts. The base, which has ouly been obtained as a colourless varnish, is prepared as follows. The aqueous solution of a salt (preferably the hydrochloride) is rendered alkaline by sodium hydroxide, and the alkaloid, which is precipitated in white flocks, is extracted by shaking with ether ; the ethereal solution, after being shaken with a little water until free from alkali, is dried with calcium chloride, and the ether removed by distillation. The base is thus left as an amorphous, colourless varnish, which is slightly soluble in water, freely soluble in alcohol, ether, or chloroform, and insoluble in light petroleum.It readily undergoes decomposition when heated, becoming brown, and forming a resinous substance. All attempts to crystallise i t from various solvents failed. Its alcoholic solution is laevorotatory, although the salts are dextrorotatory, a determina- tion yielding the following results. a[19'] = - 2.64"; 1 = 2 dm; c = 6.728. Whence Atisine hydrochloride, C22HslN02,H C1, is prepared by dissolving the base in exactly the requisite quantity of aqueous hydrochloric acid, and crystallising the salt from the aqueous solution thus obtained. It may also be crystallised from alcohol by the addition of ether. As VOL.LXIX. 5 K1522 JOWETT ON ATISINE, thus obtained, the pure hydrochloride forms long, transparent prisms, occurring either singly or in rosettes. The crystals are anhydrous, as there is no loss in weight when they are heated at 100-130" for five hours. The salt is very soluble in water and alcohol, less so in benzene and acetone, and sparingly in dry chloro- form ; it is insoluble in ether and in light petroleum. When dried at loo", it melts and decomposes with effervescence at about 296O (corr.). The aqueous solution is dextroro tatory, two determinations yielding the following results : (i) a[19"] = +0*61"; I = 2dm; c = 1.691. Whence Whence (ii) a[24'] = +0*38"; I = 2dm; c = 1.002. loo 0*38 = [a],,.= +18.90. 2 x 1.002 Mean of two determinations.On analysis- 0.1776 of salt gave 0.0684 AgC1. The molecular weight of the salt, determined by the depression of [a]= = +18.46'. C1 = 9.53. C22H3J",,HC1 requires C1 = 9.38 per cent. the freezing point of glacial acetic acid, gave the following result: Weight of salt taken.. . . .. . . Weight of solvent.. . . . . . . . . Depression of freezing point. . = 0.16'76 = 5.327 = 0.34" 3.146 0.34 39 x - = M = 360.8. C,H3,NO2,HC1 requires 377.4. Atisine hydrobromide, C22H,,N0,,HBr, prepared in a similar manner to the hydrochloride, crystallises from a mixture of alcohol and ether in long needles, which are anhydrous. It is freely soluble in water or alcohol, less so in chloroform, insoluble in ether, and melts and decomposes with effervescence at 273" (corr.). The aqueous solution of the salt is dextrorotatory, a determination giving the following results : a[15"] = +0*386"; 1 = 2dm; c = 0.7915.Whence Whence .A tisine hydkodide, C22H,,N O,,HI, cannot be obtained by the action of aqueous hydriodic acid on the base, since iodine is liberated, and a coloured substance--probably an iodo-derivative-formed. It is,THE ALKALOID OF ACONITUM HETEROPHYLLUM. 1523 however, very easily prepared by adding Mayer's reagent to a solu- tion of a salt of atisine, and treating the precipitate as before described. Atisine hydriodide is also precipitated on adding aqueous potassium iodide to a strong aqueous solution of an atisine salt. The hydriodide is best purified by dissolving it in boiling water, when, on cooling, an abundant deposit of crystals is obtained.It may also be crystallised by the spontaneous evaporation of an alcoholic solution, or by the addition of ether to the solution. The crystals are anhydrous, transparent plates or tables, occurring singly or in rosettes ; they are very sparingly soluble i n cold, more so in hot water, sparingly soluble in alcohol or acetone, and almost in- soluble in chloroform, ether, light petroleum, or benzene. A determination of the solubility of this salt in water gave the following results : I. 6.9924 solution at 90" gave 0.0926 salt. 11. 8.7992 solution a t 15O gave 0.0182 salt. Hence 1.3 grams of salt dissolves in 100 grams of water at 90". Hence 0.2 -"ram of salt dissolves in 100 grams of water at 15". The pure salt, when dried at loo", melts and decomposes with effervescence at 279-280" (corn.).The aqueous solution of the salt is dextrorotatory, two determinations yielding the following re- sults : (i) a[19'] = + 0.19"; I = 4dm ; c: = 0.1808. Whence (ii) a[19'] = +0.lo; I = 2dm; c = 0.1'74. Whence loo *.' = [a]= = +28*7'. 2 x 0.174 Mean of two determinations [a]= = +2'7*4'. On analysis, the salt furnished the following results : 0.1652 gave 0.3468 GO2 and 0.1086 H,O. C = 57-02 ; H = 7.30. 0.0914 ,, 0.1904 GO, ,, 0.0598 H20. C = 56.77; H = 7-28, 0.1926 ,, 0.097 AgI. I = 27.21. 0.0926 ,, 0.0462 AgI. I = 27.02. 0.2636 ,, 0,1312 AgI. I = 26.89. 0.3753 ,, 11 C.C. moist nitrogen at 13" and 755.4mm. N = 3.44 C22H31N02,HI requires C = 56-29 ; H = 6-82 ; N = 2.99; I = 27.07 per cent. Atisine nitrate, CZ2H3,NO2,HNO3, is best obtained by adding a slight excess of aqueous silver nitrate to a hot aqueous solution of the pure hydriodide, filtering off the silver iodide, carefully removing the excess of silver nit-rate by dilute aqueous hydrochloric acid, filtering1524 JOWETT ON ATISINE, off the precipitated silver c h i d e , neutralisiog the filtrate with dilute ammonia, and concentrating the aqueous solution on the water bath.On cooling, the salt crystallises out in very well-defined hexagonal plates, which are best purified by recrystallisation from alcohol and ether. The cryRtals, which may occur singly or in rosettes, are, like the other salts of atisine, anhydrous ; they are soluble in water, particularly in hot water, fairly so in benzene or acetone, more so in alcohol, sparingly in chloroform, and insoluble in ether or light petroleum.The dried salt melts sharply at 252' (corr.). The aqueous solution is dextrorotatory, a determination giving the following result : a[i80~ = + 0.580; I = 2am; = 1.0255. Whence loo 2 x 1.0255 o'58 = [a]" = +28*3O. On aualysis, the following data, were obtained. 0.144 gave 03458 GO2 and 0.1032 H20. C = 65.48 ; H = 7.96. 0.182 ,, 0.4368 ,, ,, 0'1302 ,, C = 65-43; H = 7-94. 0,1588 ,, 9.5 C.C. moist nitrogen at 13Oand 761.5 mm. N = 7.08, CzzH31N02,HN03 requires C = 65.34 ; H = 7.92 ; N = 6-93 p. c. In the determination of the nitrogen contained in the hydriodide and nitrate, a difficulty was encountered similar to that described by Dnnstan and Carr in the case of aconitine (Proc., 1896, 48), and concordant results were only obtained by mixing the salt with pow- dered copper oxide and lead chromate, and conducting the combustion in a vacuum.Atisine aurichloride, Cz2R3,NO2,HAuCl4, prepared by the usual methods, could only be obtained as an amorphous powder, soluble in alcohol, but insoluble in ether or light petroleum. 0.0682 gold salt, on ignition, gapve 0*0202 Au. C22H31N02,HAnClo requires Au = 28.82 per cent. Atisine platinichloride, ( C22H81N02),,HzPtC16, is a yellow crystalline powder, sparingly soluble in cold, more so in hot, water, and melts sharply at 229O (corr.) with effervescence. Au = 29.61. 0.0609 gave 0.011 Pt. The result of these analyses of pure material confirm conclusively the formula for atisine (CZzH3,NO2) proposed by Wright. When atisine is treated with alkalis or acids under varying con- ditions, no acid is eliminated, but a new base is formed.To prepare the latter, atisine i n alcoholic solution is heated with alkali for some houra, either in a sealed tube or in a reflux apparatus ; the liquid is then neutralised with aqueous sulphuric acid, the alcohol removed P t = 18.06. (Cz2H~1NO2),,H2PtCI, requires Pt = 17.78 per cent.THE ALEALOID OF ACONITUM HETEROPHYLLUM. 1525 by distillation, the solution rendered alkaline with aqueous sodium hydroxide, and extracted with ether. On distilling off the ether, a non-crystalline, colourless varnish is left ; none of the salts could be obtained crystalline, but the anrichloride and platinichloride were prepared and analysed, and the figures obtained on analysis agree best for a base represented by the formula C22H3,N02,H,0.0.171 gold salt gave 0.239 CO, and 0.0784 HzO. C = 38-01 ; H = 5.08. 0.1026 gave on ignition 0.0292 An. An = 28.4. Two separate fractions (I and 11) gave on analysis : Au = 28-06. 11. 0.0370 ,, 0.0104 ,, Au = 28.10. Au = 28.08 per cent. The platinichloride, which melts at 236' (con-.), was analysed : 0.0536 gave 0.0094 Pt. Pt = 17.53. (C,,H,,NO,,H,O),,H,PtCJ, requires Pt = 17-21 per cent. The same bnse was obtained when atisine was heated in aqueous solution with dilute sulphnric acid, the analysis of the platinichloride thus formed giving the following result : I. 0.0588 gave 0.0165 Au. C~H,N02,H,0,HAuC14 requires C = 37-82 ; EI = 4-87 ; 0.0298 salt gave 0.0051 Pt. Calculated, Pt = 17.21 per cent.When the hydriodide is heated with fuming hydriodic acid, no methylic iodide is formed, thus proving the absence of methoxyl groups in the molecule. When atisine hydriodide is heated with soda lime, a white sub- stance sublimes which has the odour of a cresol ; this is insoluble in cold water, slightly soluble in hot water, but easily in alcohol 01' ether. Lack of material prevented the further examination of this decomposit,ion product. Professor Cash, of Aberdeen, who has examined the physiological action of atisine nitrate, reports that in small doses it is not toxic, and that its action in some respects resembles that of aconine. Pt = 17.11. The results of this investigation show that atisine does not present any close analogy to the alkalo'ids of the other well known species of aconite ( A . napellus, ferox, japonicum). The molecule is apparently less complex and much more stable, and since it yields a hydrate when heated with alkalis or acids, i t might be inferred that i t is the anhydride of atisine monhydrate ( C22H,3N03). There would thus be a relationship between these bases similar to that existing between aconine and pyraconine. The material used in ihis investigation was collected in India, at FOL. LXIX. 5 L1526 DOUCJAL: EFFECT O F HEAT the instance of the Scientific Department of the Imperial Institute, a,nd the inquiry has been conducted in the Research Laboratory of the Pharmaceutical Society. In conclusion, I desire t o express my warmest thanks to Professor Dunstan, both for having suggested the research, and for the very kind encouragement given to me during the progress of the work.

ISSN:0368-1645    

DOI:10.1039/CT8966901518

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

1526 DOUCJAL: EFFECT O F HEAT C - E f e c t of Heat on Aqueous Solutions of Clz~onze Alum. By MARGARET DOUIE DOUGAL. IT has long been known that when an aqueous solution of chrome alum is heated, its colour changes from violet or purple t’o green ; the alteration, which begins at about 70°, is apparently complete in a few minutes, even in nioderately strong solutions, a t 100’. On evapo- ration, the green solution yields a green, nou-crystalline mass. If the liquid is allowed to stand, the green colour persists for some time, especially if the solution is dilute, but it gradually reverts t o the original purple, and ultimately the solution deposits the dark purple octahedra of ordinary chrome alurn. Various explanations have been given of this phenomenon. According t o Schrotter (Aqiqa.Plzys. Chem., 1841, 53, 513), Lowel (J. Phuym., [3], 7, 32l), and, more recently, I h r d (Compt. Tend., 84, l089), the alteration of colonr is simply the result of the change of bydration ; Berzelius (Ann. Phys. Chem., 61, 1) and Premy (Compt. rend., 47, 883) considered it was due to the formation of a basic salt, whilst Fischer (Kustney’s arc hi^, 14,164) and Jacquelain (Conzpt. rend., 24, 439) surmised that it was the direct effect of the separa- tion of the chromic sulphate from the alkali sulphate. None of these explanations is altogether sufficient. I t might be inferred from Graham’s work on liquid diffusion that, chrome alum would undergo dissociation in aqueous solution even in the cold, and therefore tlhe mere separation of the chromic sulphate from the potassium sulphate would not alone account for the change.That the solution experiences a profound change on heating is obvious f r o a the circumstance, pointed out by Favre and Valson (Cowpt. rend., 74, 1023), that only a, portion of the sulpliuric acid present in the green solutioii is pre- cipitable in the cold by barium chloride, and that prolonged boiling with barium chloride is needed to effect its entire separation as barium sulphate ; whereas the violet solution at ordinary temperatures at once yields up its sulphuric acid to barium chloride. The greenON AQUEOUS SOLUTIONS OF CHROME ALUM. 1527 solution further differs from the violet in containing, as first shown hy Kriiger ( A m . Phys. Chem., 61, 218), free sulphuric acid. At Professor Thorpe's suggestion, and under his direction, I have been led to investigate this phenomenon, in the expectation that the true explanation might be found to depend upon the formation of Recours's chromosulFhuric acid, which is known to behave towards barium chloride in the remarkable manner above mentioned.The inquiry was begun in the early part of 1894, in the labora- tory of t,he Royal College of Science, South Kensington, but, owing to other engagements, its completion has been delayed. I n view of the recent work of Monti ( N . Cirn., 1896, 43, 212-216) and of W. R. Whitney (Zeits. physikal. Chern., 1896, 20, 40), I am zow induced to put together the results I have obtained. A variety of physical methods may be employed to throw light upon the nature of the change attending the alteration in colour of the chrome alum solution.Sprung has studied the variation in the viscosity or internal friction of the violet and green solutions, and Lecoq d e Boisbaudran, by dilatometxic observations, has noticed the change in density. I find that the alteration in density of even a dilute solution of chrome alum, after boiling, may readily be detected by the specific gravity bottle. A weighed amount of chrome alum was dissolved in a known volume of water, and portions of the solution were heated to about 100' under such conditions that no evaporation was possible. The weight of the green liquid required to fill a specific gravity bottle was then determined, a precisely similar experiment, under identical conditions of temperature, &c., being made with the violet solution.The several weights of the two solutions obtained in three experiments were as follows : Violet solution. Green solution. Grams. Grams. I. ......... 100.4028 100- 376 5 IT. ......... 101-2537 101.1712 111. ......... 2025096 102.3567 The first experiment was made on a 1 per cent,. solution, the second on a 2$ per cent., and the third on a 5 per cent'. solution. The actual amount of the change depends on the duration of the heating and on the lengt'h of time which has elapsed since the green solution had been prepared. I t will be observed, however, that in all cases the green solution was less dense than the violet solution; hence the transforniation is accompanied by expansion, the result probably, of the production of the free sulphuric acid. I have, further, made a series of observations on the relative rates of the diffusion of the green and violet solutions.The method 5 L 21528 DOWAL: EFFECT OF HEAT adopted was that of Graham. Two pt-ecisely similar flat-bottomed glass crystallising dishes, of equal diameter and depth, and of about 100 C.C. capacity, mere placed each at the bottom of a flat-bottomed glass dish of about 1000 C.C. capacity, and of equal depth and width. These were placed on felt. Each of the smallel* dishes was then filled up to a definite point with the solution to be diffused. The dif- fusion experiments were carried on in an underground room of fairly uniform temperature, into which the direct sunlight never penetrated. The solutions to be converted into the green variety were boiled for several hoursin a flask connected with a reflux condenser.They were cooled as rapidly as possible by means of ice, and were allowed to stand in the cellar where the experiments were made, together with the violet solution, until both had acquired the temperature of the air. Every known precaution was taken to make each pair of experiments as strictly comparable as possible. The required amount of water, which, meanwhile, had been standing along with the flasks containing the chrome-alum solution and the necessary apparatus in the diffusing room, was run in fyom a dropping funnel, the end of which was furnished with a narrow, glass tube, drawn out till merely a fine jet of liquid passed, and bent at right angles, so that the water as i t flowed impinged on the side of the outer basin, and, in falling, made as little disturbance as possible in the water already in the dish.As the water reached the top of the dish containing the chrome alum solution, it was allowed to impinge on the side in such manner that the overflow of the water into the inner vessel should be as gentle as possible. The depth of the pure water above the level of the chrome alum solution was about the 8ame as that of the solution itself. The outer vessel was covered with a glass plate, a bell-jar placed over the whole, which was then covered with brown paper. In this way it was hoped that the temperature-change would be as little as possible. At the end of the period of diffusion a small glass plate, which was gently introduced into the liquid by means of a stout platinum wire, arranged so that it held the circular plate by three hooks and was readily detachable, was adjusted so as to cover the small dish. The diffusate was then syphoned off into a beaker, the few drops remaining in the dish and on the surface of the plate being removed by a finely pointed pipette. The chromium iu each diffusate was determined by precipitation with ammonia in the usual way, and the sulphuric acid in the filtrate estimated by boiling with hydrochloric acid and barium chloride, Iu all, seven independent pairs of experiments were made with two different solutions, each containing about 1 per cent.of chrome alum. The results may be tabulated as follows :ON AQUEOL-S SOLUTIONS OF CHROME ALUM.1529 Cr. ---. 0 ‘0446 0 -0345 0 9490 0 -0652 0 -0656 0 -0670 0 -04’76 Volumo of solution of chrome nluin. 0’1’742 0*1.158 0 ‘2035 0 -2697 0.2802 0-2859 0.1’7’78 90 *o C.C. 2 , 2 1 1&0 :: 150.5 ,, 143.0 ,, 64.5 ,, 0.0393 0.0314 0 -0465 0 -0641 0.0629 1 0.0643 i 0.0469 Volume of water into which diffu- sate p s d . Violet solution. Green solution. SOJ. - -~ 0 -1818 0 -1 531 0 *2184 0 293 1 0 *2929 0 -3101 0 *1788 All the experiments made are given. In considering the results it will be understood that the several pairs are, strictly speaking, only comparable with one another, as the conditions in the case of one pair and another were not necessarily the same ; time, temperature, atrength of diff usate, amount of init’ial change, amount of retrogres- sion, &c., d l affecting the results.I n the outset there was nothing to determine the best strength on which to make the observations. In dilute solutions the retrogression from green to violet is slowest ; but, on the other hand, the actual mass of the salt diffused depends on the initial strengt-h of the chrome solution. In every case it is noticed that the green diffusate contains less chromium and more sulphuric acid than the violet solution ; this is compatible with the assumption that the green solution contains a colloidal, and therefore slowly diffusing chromosulphuric acid. So far as they go, then, these results are in harmony wit’h the coii- clusion already drawn by Monti and, by inference, by Dr. Whitney, t h a t when a solution of chrome alum is heated, it is resolved into a mixture of potassium sulphate, chromylsulphuric acid, and free sulphuric acid.As Whitney has shown that only one-sixth of the sulphuric acid originally present in the chromic sulphnte is changed into free sulphuric acid, whereas Favre and Valson found that the green solution gives up one-third of the sulphuric acid present in the original chromic sulphate to barium chloride, in the cold, we may formulate the entire change as follows : The general result, however, is unmistakable. ~[C~.I,(SO,)~,K~,SO,] + H,O = [C1~~O(SO,)~]SO~ + 2K2S04 + HgSO,. The curious fact that the green solution of chrome alum, on heating, transforms its contained snlpharic acid into a state in which it, is not precipitnble in the cold by barium chloride, has its analogy in the remarkable behaviour of certain cobaltamines. Thus, as Jiirgensen bas shown, chloropurpureo-sulphnte does not yield hydro-1530 POPE : THE REFRACTION CONSTANTS cbloric acid on heating with concentrated sulphuric acid, nor does its solution give a precipitate with silver nitrate. We must assume, therefore, as in the case of the chromosulphnric acid, that one portion of the acid radicle has not the same relation towads the rest of the compound as the other. It is hardly to be expected that the fact of the elimination of the acid radicle, as free sulphuric acid, in the course of the change of the violet chromic sulphate to the green compound will be found to be singular. The observations of Gerlach would seem to show that iron alum behaves in a, somewhat similar manner. The curious behaviour of aluminium acetate, discovered many years ago by Crum, appears to be a, phenomenon of the same order. Here, too, we observe the gradual elimination of acetic acid, dissipated because i t is volatile, with the simultaneous formation of a colloidal substance. 1 desire, in conclusion, to express my thanks to Professor Thorpe for his advice and assistance in the prosecution of these experiments.

ISSN:0368-1645    

DOI:10.1039/CT8966901526

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

1530 POPE : THE REFRACTION CONSTANTS CI. -.The Rt@uction Constunts of Crystalline Salts. By WILLIAM JACKSON POPE. THE investigation of the refi-actiou equivalents of liquids by Gladstone and others, has led to results which have so materially advanced our knowledge of moleciilar s tructuro that it is perhaps remarkable that no similar results have yet been obtained with crystalline sub- s tames. During the last 30 years, laborious determinations of the densities and refractive indices of long series of salts have been made by Topsije and Christiansen, Soret), Tutton, and others, often with the express object of obtaining a direct relationship between refracttire power and chemical coniposition ; this, however, the most important aim of such work haa not hitherto been attained. Proof is advanced in the present paper that the molecular refractions of crystalliue singly or doubly refracting salts are practically additive quantities, so that the inter-relationship of the refraction constants arid the density, on the one hand, and the composition of a salt, on the other, is of an extremely simple nature, and that on this assumption the refraction constants of a large number OE salts examined by the authors named above can be very closely correlated.The refractive index r , either of aliquid or of an isotropic solid, does not vary with the direclion, and may be a t once combined with the molecular volume in any of the usual ways in order to obtain the molecular refraction. Consequently, using the Gladstone formula,OF CRYSTALLINE SALTS. 1531 the molecular refraction of all cubic crystalline substances is obtained from the formula, V(r-1), where V is the molecular volume.If the crystalline substance be anisotropic, possessing either two or three principal indices of refraction, it is not immediately apparent in what way these several indices should be combined in order to yield a single refraction constant. Two cases must be here dis- tinguished, the one of uniaxial substances having two principal refractive indices, and the other of hiaxial crystals possessing three principal indices of refraction, A uniaxial crystalline substance has an extraordinary refractive index e and an ordinary one 0 ; the optical indicatrix of such a crystal is a spheroyd of which the principal circular section has the radius 0, and the axis of revolution has the semi-diameter e.The 40~ee7.r volume of this spherojid is --, and is equal to t,hat of a sphere of 3 radius T = $‘ox This mean refractive index, r , is a single refraction constant comparable in kind with the refractive index r of an iso- tropic or liquid substance. In a biaxial crystalline Substance, the opt,icd indicatrix is an ellipsoid, having for its three principal semi-diameters the three prin- cipal refractive indices a, p and “1 ; the mean refractive index of a biaxial substance is that radius vector ’i’ of the indicatrix which is the radius of a sphere equal involume t o the ellipso’id. The volumes of the ellipso’id and the sphere are 4ug*pr $1.7 5i- and __ 3 3 respectively ; the required mean refractive index 1- is therefore the geometric mean of the refractive indices a, /3 and “1.When a doubly refracting substance, having the principal refractive indices 01: 13, and c/, or o and e , is melted, and thus made amorphous, the wave-surface becomes a sphere of radius, r = or ,;/Z, provided no change attends the melting beyond the destruction of the regular orientation of the mass units of the crystal. Similarly, if the crystalline substance be dissolved in a solvent, if dissolution have only the purely physical effect of destroying the regular arrangement of the mass-units, the end result, so far as the specific refraction is concerned, would be the same as that of dissolving an isotropic substance again of refractive index r = q F v or TX It should therefore be possible to use the values of r thus obtained for calculatiag the molecular refractions of crystalline doubly1532 POPE : THE REFRACTION CONSTANTS refracting substances in n manner slinil~r to that used in the case of liquids, and the refractive index of an isotropic substance and the mean index T of an anisotropic one should be quantitias of the same kind, and have the same physical significance.Instea,d of calculating T as a geometric mean, it may be obtained as an arithmetic mean with sufficient accuracy f o r the experimental nurnbei-s, and much greater convenience in working ; so that The use of these approximate values of r introduces no appre- ciable error, except when substances of extremely high double refi-ac- tion are being dealt with; consequently, excepting in a few such cases, the arithmetic means will be used.Further, the results obtained by using a molecular refraction formula of the Gladstone type will alone be discussed in the present paper ; au investigation, however, 0; the Lorenz and Lorentz formula has been commenced, in order to ascertain which of the two types of expression is the more applicable to crystalline substances. On displacing T in the Gladstone formula V(r-1) by the appropriate functions of the refractive indices of the crystalline substances to be considered, the expressiou naturally takes three different forms, corresponding with the three type3 of optical indicatrix possible amongst crystalline Substances. The molecnlar refraction formula is thus .................. V(r - l)..(11, for cubic crystals ; for those belonging to the hexagonal and tetm- gonal systems it is ( 9 ) 9 v{ (+ - l} ................ 20 + e whilst for rhombic, monosymmet,ric, and anorthic crys tnls the expres- sion to be used is ............ v{(" + + y)- l} (3) * The fact that formule (2) and (3) should be for anistropic sub- stances what the ordinary Gladstone formula is for liquids, has been shown by Dufet (Bull. Xoc. franc. de Min., 1887, 10, 77), who also used the expressions for calculating the molecular refractions of a series of sodium arsenates and phosphates. Dufet, Eowever, only applied the method of calculation to a small number of salts of somewhat complcx nature, and consequently failed to obtain any general results; it is probably owing fo this circumstance that the importance of the formuh has not been recognised by those who have worked at refraction constants.O F CRYSTALLINE SALTS.1533 1 *32889 1 -33038 1 -33113 1 -33298 1 -33622 1 ‘33713 It having now been demonstrated that expressions (2) and (3) are merely expanded forms of the Gladstone formula, and that their use is necessitated by the complex optical properties of anisotropic substances, these formulse will be used without further comment, as occasion arises, in connection with the various crystalliim substances dealt with in the following pages. 5 -9304 5 ‘95’73 5 -9708 Ci -0042 6 *0445 6 *G790 It is, in the first place, of great importance to determine whether liquefaction or dissolution causes the molecular refraction of a crys- talline substance to change ; satisfactory data seem available in one, and only one, case, namely, that of water and ice.The refraction constants of water, an easily purified substarce, have been determined by many observers to a degree of accuracy far greater than is neces- sary for our purpose. In the first part of Table I, van der Willigen’s values for the refractive indices of water for various lines in the spectrum, at a, temperature of 2 0 * 2 O , and a density of 0.99885, are given ; the third column gives the molecular refractions calculated fi-om the molecular volume, and the corresponding refractive indices. The refractive indices, o and 6, oE the hexagoual uniaxial ice have been accurately determined by Pulfrich (Am. Phys. Chem., 1888, 34, 326), and are given in the second part of Table I ; the determina- tions were made at Oo, and Bunsen’s value, namely, 0.91674, for the density of ice at that temperature is used in calculating the mole- c u l s ~ refractions.The differences A between the molecular refrac- tions in the liquid and solid state, are stated in the last column of the table. TABLE 1. Water. 1- A . . . . B .. .. c .. .. D . . . . E .. .. F .. .. 1 -30496 1 *30M5 1 -30715 1 -30911 1-31140 1 -3 1335 Ice. e. 1 *30626 1 ‘3W75 1 *30861 1 *31041 1 -31276 1 * 31473 2.. - 1 -80539 1 -30688 1 -30764 1 -30954 1 -31185 1 a 31381 V(r - 1). -- 5 *98’rS 6.0255 6 *0404 6 *0778 6 -1231 6.1666 0 -0574 0 -0682 0 -06‘36 0 ‘0’736 0 9’786 0 -0876 A glance at Table I suffices to show that the molecular refraction of liquid water is not identical with that of ice, but that the differ- ences between them are of the order of 1 per cent., a quantity which cannot be accounted €or as experimental error ; in fact, calculating the value of ? a D f o r ice from the value for water, on the assumption1534 POPE : THE REFRACTION COSSTANTS that the molecular refractions are the same in the two states, we get the value 1.30579, which is smaller than that of either the ordinary or the extraordinary refractive index of ice.It follows, consequentJy, that the molecular refraction of a crystalline substance is not neces- sarily the same as that of the same substance in the liquid state. I n a recent paper by Tutton (Trans., 1896,69,507), which contains a large number of data respecting the refraction coilstants of crystals, the conclusion is drawn (p.525) that "the matter in a crystal ha^, for refraction purposes, the same average effect as the same matter uncrystallised." This conclusion evidently does not hold in the case of ice and water and, as will be presently shown, is not generally true. In the case of a salt dissolved in water, the molecnlar refraction of the dissolved matter changes more rapidly with the concentration i n concentrated than in dilute solutions ; morcover, an inspection of the curves obtained by plotting concentration against molecular refraction shows that in dilute solutions the change of curvature is not rapid, and even in strong solutions the curve deriates but little from a straight line. By continuing the experimentally obtained cuives outside the limits of the experiments, the molecular refraction of the salt in an infinitely dilute or 0 per cent., and i n an infinitely concentrated or 100 per cent., solution can be determined ; these two values would be, in terms of the electrolytic dissociation liypothesis, the molecular re- fractions of the wholly dissociated and the non-dissociated salt.Owing t o the paucity oE experimental data, such a method of calculating the inolecular refraction in an infinitely concentrated solntion only gives a very poor approximation, but the results obtained show at least that as the concentration of the solution increases, the molecular re- fraction of the dissolved salt continually approaches that of the same salt in the crystalline state, as calculated by the method described above .Thus, Gladstone and Hibbert (Trans., 1895, 67, 838) quote the numbers used in Table I1 for the molecular refractions of rubidium and caesium sulphates in aqueous solutions. The concentration of the aqueous solution is st'ated in column 2, and the corresponding molecular refraction for the C line is given in column 3 ; column 4 gives the molecular refraction in a 100 per cent. solution calculated from the values in the two solutions of highest concentration, on the assumption that the refraction-concentration curve is a straight line through these two concentrations u p to 100 per cent. Column 5 contains the molecular refract'ions of the solid salts, calculated by expression (3) from Tntton's number8 (Zoc. tit.).1534 POPE : THE REFRACTION COSSTANTS that the molecular refractions are the same in the two states, we get the value 1.30579, which is smaller than that of either the ordinary or the extraordinary refractive index of ice.It follows, consequentJy, that the molecular refraction of a crystalline substance is not neces- sarily the same as that of the same substance in the liquid state. I n a recent paper by Tutton (Trans., 1896,69,507), which contains a large number of data respecting the refraction coilstants of crystals, the conclusion is drawn (p. 525) that "the matter in a crystal ha^, for refraction purposes, the same average effect as the same matter uncrystallised." This conclusion evidently does not hold in the case of ice and water and, as will be presently shown, is not generally true.In the case of a salt dissolved in water, the molecnlar refraction of the dissolved matter changes more rapidly with the concentration i n concentrated than in dilute solutions ; morcover, an inspection of the curves obtained by plotting concentration against molecular refraction shows that in dilute solutions the change of curvature is not rapid, and even in strong solutions the curve deriates but little from a straight line. By continuing the experimentally obtained cuives outside the limits of the experiments, the molecular refraction of the salt in an infinitely dilute or 0 per cent., and i n an infinitely concentrated or 100 per cent., solution can be determined ; these two values would be, in terms of the electrolytic dissociation liypothesis, the molecular re- fractions of the wholly dissociated and the non-dissociated salt.Owing t o the paucity oE experimental data, such a method of calculating the inolecular refraction in an infinitely concentrated solntion only gives a very poor approximation, but the results obtained show at least that as the concentration of the solution increases, the molecular re- fraction of the dissolved salt continually approaches that of the same salt in the crystalline state, as calculated by the method described above . Thus, Gladstone and Hibbert (Trans., 1895, 67, 838) quote the numbers used in Table I1 for the molecular refractions of rubidium and caesium sulphates in aqueous solutions. The concentration of the aqueous solution is st'ated in column 2, and the corresponding molecular refraction for the C line is given in column 3 ; column 4 gives the molecular refraction in a 100 per cent.solution calculated from the values in the two solutions of highest concentration, on the assumption that the refraction-concentration curve is a straight line through these two concentrations u p to 100 per cent. Column 5 contains the molecular refract'ions of the solid salts, calculated by expression (3) from Tntton's number8 (Zoc. tit.).1536 POPE : THE REFRAUTION CONSTANTS conclude that it was used merely becawe, in the cages of the few salts which the author compared in the two states, i t happened to give practically the same molecular refraction f o r the crystalline salt, as was found in solution. The calculation of the mean molecular refraction of ci-ystalline substances from two of the three principal indices of refraction, thus neglecting one index which is of similar physical significance to the other two, can only be used in those cases in which the median refractive index /3, chances to be the arithmetic mean of the two extreme ones a and y.In Table 111, column 1 gives the two metals present in the double sulphate, column 2 gives Tutton's molecular refractions for the salts, and column 3 gires the molecular refractions calculated from expres- sion (3) ; columns 4 and 5 give the increase in molecular refraction for Tutton's numbers and my own, on passing from zt salt containing potassium to one containing rubidium, from the rubidium to the cesium salt, and from the potassium to the caesium salt ; these three quantities are arranged in sets of three, each corresponding to a particular dyad metal.TABLE 111. Metals in srtlt. GMg ...... Xb2Mg.e . . . CsZMg.. .... K2Zn ...... Rb2Zn ...... Cs2Zn. ...... K2Fe ....... Rb2Fe ...... KZNi ....... Rb2Ni.. .... Ca-Ni ...... K,Co ....... Rb,Co,. .... C&o. ...... I(2CU. ...... RbCUu.. .... cs,cu ...... RbzMn ..... (:Ei,J'lU. ..... Cs,Cd ...... K2SO4.. .... Rb&3OI.. ... CS,SO+, . , . . CS2Fe. ...... Rb2Cd.. .... Xolecular refrac- tion. Tutton. 92 -41 97 '73 107 '42 95-90 101 * 22 110.75 96 '92 102 -03 112.00 96 -33 101 50 111 -25 96 *63 101 -91 111'76 97-29 102 -54 111 -80 102 -95 112 -499 105 '80 114 -58 32 '30 37 -79 47 -77 Pope. 92 -08 97 -443 107 '21 95 -65 101 -07 110-69 96 -35 101 -88 111 -90 96 *16 101 -42 111 -27 96-38 101 -78 111 90 96 *87 102 -16 111 *52 102 074 112 -34 105 *61 114.41 38 -35 37 -74 47 -81 Tutton. - 5 -32 9 -69 15 '01 5-32 9 -53 14 -85 5.11 10 -07 15 *18 5 *l'r 9 9 5 14 * 92 5 -28 9 '85 15 '13 4 -25 9 '26 13 -51 9 -54 8 -78 5'39 9 -Y8 15 '37 -.- Pope. ~- 5 '443 9 -73 15 -13 5 -42 9 *62 15 *M 5.53 10 002 15 -55 5 -26 9 -85 15 -11 5 *40 9 -92 15 -32 5 -29 9 -36 14.65 9 -60 8 -83 5 4 9 10 -07 15 * 56 - - Molecular refraction xblcnlated. -- - 97 -48 107 -21 95 '63 101 '03 110.76 96 -53 101 *98 111 -66 96 -11 101 -51 111 -24 96 *a 101 '84, 111 -57 96 -68 102 -08 111 *81 102 -68 112 '41 105 '16 114 '89 - - -OF CRYSTALLINE SALTS. 1537 I(, to Rb,. The mean and limiting values of these three differences are tabulated in Table IV.Rbz to CS,. I(, to CS~. TABLE IV. Mean. Limits. I Mean. 1 Limits. . 1 Limits. Tutton.. . . Pope . . . . . I-- -- 4.25-5.39 5 *26-5- 53 4-30 4.30 4.49 4.36 -- 4-27 4-40 4.69 4-45 --- 5 -07 S *7&10 '07 9 -56 13 -51-15 *37 5 '40 8 '83-10 *07 9 -62 14 *65-15.56 I I 1 --- Mean. . . . . . . . . Mean. - 3 -55 14 97 15 -13 The limits of the differences are very much closer with my values that with Tntton's amongst the differences between corresponding potassium and rubidium salts, the mean deviation from the mean of my values is less than a quarter of that of Tutton's. A lack of uniformity amongst the latter might very naturally be expected to attend the neglect of the median refractive index p. It has now been shown tha.t within very narrow limits a constant increase i n molecular refraction occurs on changing one of the potas- sium double salts to a rubidium or cesium salt, if the dyad metal remains the same ; i t is also easy to demonstrate that on changing the dyad metal, whilst keeping the alkali metal the same, a practically constant increase occurs.The increase in molecular refraction for the ray C which occurs on passing from a magnesium salt to any of the others is given in Table V. TABLE V. Mg to 1 Zn. j 3.57 I 3.59 ' 3-48 Ni . 4 -08 3 -94 4 -06 4 -03 Co. I Fe. ~ I--( cu. -- 4 -so 4 *68 4 -31 4 -60 ,-- Xn. Cd. - 8 '13 7 -23 7 '68 ~ ~ Knowing the molecular refiaaction of one of these double salts, it is now possible t o calculate that of any of the others by merely adding or subtracting the average differences for the alkali metals (Table IV) and the dyad metals (Table V).The numbers given in the last column of Table I11 are calculated in this way from the molecular refraction of magnesium potassium sulphate ; the agree-1535 POPE : THE REFRACTION CONSTANTS ment between the found values in column 3 and the calculated values in column 6 is very close. This agreement at once suggests as highly probable that if tlle molecular refractions of other series of salts weye dealt with, these constaiits would turn out t,o be, iu the main, additive ones, and that it would be possible to calculate with fair accuracy the molecular refraction of a crystalline salt, froni a table of atomic refractions ; this view was found to be fully confirmed on examining the refrac- tive indices and molecular volumes of a large number of other salts.Amongst the double salts discinssed above, there seems but little indication that the molecular refraction is other than A purely additive property, probably because most of these salts are iso- morphous and of the same type ; dealing with salts of various con- stitutions, however, it may possibly be shown that the atomic refractions are merely average numbers and really vary with the type, just as Perkin (Trans., 1896, 69, 1025) has recently found with the molecular rotations of liquids. The molecular refractions of crystalline salts are, in t,he main, tho sums of definite increments of refraction due to the atoms or radicles contained in the molecule. By assigning definite refraction constants to the various inorganic basic and acidic radicles, it becomes possible t o calculate, with fair approximation to the founcl values, the molecular refraction of any particular crystalline salt ; the particular values of the various refraction constants are cal- culated by a process of trial and error froni the observed values of the molecular refractions of the solid salts.Table VI gives these atomic or equivalent refractioii constants for a large number of basic and acidic radicles for the D my. TABLE VI. Radicle. --- Na. ........ Li ........ K ......... Rb ........ cs.. ....... NH4 ...... Sr ........ Ba ........ Pb ........ T l . . ....... 211 ........ Xi ........ Mg ....... Refraction equivalent. 4 . 1 4 a 4 5 7 -64 10 -31 15 -25 11 ‘38 13 *95 18 *94 30 -02 22 -14 8 -81 12 -40 12 *84 Radicle.-- Go. ...... Pe” ..... Fe’” ..... cu ...... Mn.. .... Cd ...... 81. ...... Cr”’ ..... Ga ...... Cl ....... Br.. , . , , . NO,. .... r ........ Refraction equivalent. 13 -18 13 -38 23 ‘03 13 -5z 14 ’04 16 *53 14 *61 22 *25 16 ‘52 10 -99 17 -26 29 -08 13.47 Radicle. so,. ..... SeO,. .... CrO,. .... ClO, .... ErO, .... sao, ..... YIICI, .... SiB, ..... &PO, ... H2As04. . H,O (of crystal- lisation) Refraction equi d e n t . 17 -08 24 ‘11 37 ‘13 17 -86 23 ‘0 34 *30 86 -5 11 *51 21 -6 27 ‘72OF CRYSTALLINE SALTS. 3 539 Ln Table VII, these refraction equivalents are used in order to calculate the molecular refractions given in column 6 ; t’he values deduced from the observed values of the refractive indices and mole- cular volumes by the use of formuls (1), (2), and (3) are stated in column 5.Column 4 denotes the crystalline system of the salf, column 3 indicates the authority for the experimental data, and columns 7 and 8 state the real and percentage differences between the found and calculated values. I n the few cases in which data for only one salt containing a particular radicle are available, the equivalent refraction of the radicle has been calculated from the molecular refraction of that salt alone; these cases are denoted by dashes in the columns of differences. Twenty-five of the salts were examined by Tnttotl (T) ; it will be noticed that in their case the agreement between the observed and calculated values is very perfect. Another set of 45 salts was ex- amined by Topsoe and Chr.ietiansen(T and C) (Ann.C h i m Phys., 1874, [5],1, 5), in the hope that the results might lea8d to some generalisa- tion of the kind now brought forward ; the agreemeut between the found and calculated values is here not quite so good as in tlhe case where Tutton’s data were used, owing probably to greater experi- mental error. Many of the values (G) are taken froin Gladstone and Hibbert (Trans., 1895, 831), and some ( B ) are from a recent papei. by Le Blnnc and Rohland (Zeits. physikaZ. Chem., 1896, 19, 261) ; the latter seem to have been determined by Le Blanc’s method (Zeits. physilial. Chem., 1892, 10, 433), the accuracy of which has not yet been satisfactorily established. The long series of alums (S) examined by Soret (Arch. Sci. Fhys. ATat., 1884, [ 3 ] , 12, 553) is also used in the table. These salts belong t o the cubic system, and con- sequently no complication arises as in tbe case of salts possessing several refractive indices.Gladstone (Phil. Mag., 1885, 20, 162) was thus able to deal with Soret’s data, and used the refractive indices obtained for the C ray. Several of the experimental values were obtained by Dufet (D). It is to be observed that although fire different crystalline systems are fully represented, necessitating the different manipulation of the refraction constants, the agreement between the obsei~ed and calcn- lated molecular refractions is of t’he same order in each system. The differericcs between the observed and calculated values, further, are of somewhat the same order as the experimental error may be judged to be in most cases; although none of the authors whose data are employed give any indication of the magnitude OE the experimental error, the latter is in some cases undoubtedly large, as may be seen by comparing those salts of which two determina- tions, apparently of equal acc1ii’acy, are qnoled.The expelimental1540 POPE : TRE REFRACTION CONSTANTS .... _ _ ~ . .... - ........... ... h W P $ k u) 5 . . . . . - . . . . . . . . . . . . ...... .~ - .. - n .. ~~ -. . ~~. . - __ ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - ^ . . - - - " - - - ^ - - . . - . . . . . . . . . . . . . . . . . . .......... . ...... ~~ ~. .... __ - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : : : : : : Q : :t'9. 1- 9v. 2 - T I . O + 8P. 0 + 16.0 + 88.0 + €0. 8 + W.O+ 08. 8- 08.0+ 99. z + 19.0 + 80*2+ €P.O+ 98.0- 09.0- 80.0 + 92. o+ 4s. o+ 10- 0 + 92.0- &V- 1 - €1.0+ 479.0- 02.0 + v2.0 + - ................................... O'H9'913~S~H 0"H 9 '98!SnM 0zH9'gd!S% 'OzH9'9d!SUZ ' 'OzH9'9d?S!N I ' OZH9'96?Sn3 ............... 96!SZ(pHN) * a * Q~HS*O~S!N 06H9"OaS%41 OZHL"0WW OUE4"0S% ................... OzH4"OSnZ .................. O~HS'~OS!N ........................ O~EL"OS!N OaF'H tOS"s3 oszq21 OSQ O~ HP ( P ~ a ~ ) ~ 3 Z ( * ~ ~ ) .......... o~HH~';(~o~s)~o~(~HN) oZ H~'~(~o~s)!N~OHN) O ~ H 9 ' z ( ( P ~ a ~ ) a a z PHN) oZmLz ( P ~ a ~ ) ~ ~ z ( b ~ ~ ) o ~ H ~ ' ~ ( p ~ ~ ~ ) % z ( + ~ ~ ) O ~ H S ' ~ ( p ~ a ~ ) ~ ~ z ~ ~ j ................... .................. I ................. ................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .................. ................... .................... p .............................................. ......................... .......... . . p p .......... .......... .......... .......... .............. .............. 0:H 9':( '0 a S)nEf)I O6H9'"('0~S)03"H .............. .----- 'w3 V9 €9 29 T9 09 6V ' s g m LP 9P 9f w €V zv 19 OP 66 86 t 8 96 sf8 'PI SF: Z I T8 OE 62 82 0w w TABLE VIL-canbinued. cn ,,I& Difference A. Number. 61 NH4H2POJ.. ................... ti2 NaH2Y0,,2H,0 ................ 63 NaH2P04,H,0.. ................ 64 KH~ASOJ...... ................ 65 NH4H&04.. .................. 66 NaH2As0J,2H20.. .............. 6'7 N~LB~AEO~,H,O.. ............... 68 NR~AI~(SO~)~,~~H~O ............ ......... ............. 6'3 (NH4)?812(S04)2,24H20 70 K?A1,(804)1,?4H20 71 ............. 9 9 ............OF CRYSTALLINE SALTS.1543 I : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......... ....-.,..--.-.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....,........... ......... . . . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I . . . . . . I . . - . . . . I d : : : . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Y . . . . . . . . . . . . . . . . .ow . . . . . - . . n I ) - - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . - . - . . . - . . . . . * . . . . . . - . . . . - - . . . . .'FABLE VII-continued, i Number. Salt. 109 110 111 112 113 114 115 Mg (Br03)2,6H20 ............... Zn ( Br03) 2,6H20. ............... Ba(NO&. ..................... Sr(N03)2.. ..................... ........................ Pb(N03)s ...................... )) ...................... Obsei-r er. I I V(!r - 1). Observed. Crystalline sptem. D. T. afid C. B. T. and C. I% 9 ) Cubic.. ......... ,, ........... )) ........... ), .......... ) ) ........... ,) ........... ............. 86.88 93 -10 45.96 45 -80 40 *66 57 -14 5'7 026 Calculated. -- 89 so1 92 *60 45 -88 45 -88 40 '89 56 -96 56 -96 w crc * rp. Difference A. Real. ---- + 2 -13 -0.50 -0 S O 8 + 0 nos + 0 -23 -0.18 -0 -30 Percentage.+ 2.4% -0.54 -0 '16 + 0 -16 + 0 '57 -0 -31 -0.53OF CRFSTALLIXE SALTS. 1545 error, due probably to impurity of the salts, is in the case of the indium alums so great that no trustworthy value for the atomic refraction of indium could be calculated. The atomic and equivalent refractions given i n Table VI differ not a little from those which previous workers in this subject have deduced from observations made on solutions. This, although rather inconvenient f o r purposes of comparison, is perhaps not wholly a disadvantage, as it may assist in correcting some of the very generally prevalent fallacies re3pecting atomic refractions. These numbers are 'purely empirical values, and d3 not necessarily possess any connection with the refraction constants deduced froin observations made on the free elements themselves (compare Briihl (Zeits.physikal. Cheuz., 1891, 7, 1). It does not indeed at first sight seem a t all logical to deal with atomic constants in the case of so highly constitutivz a property as molecular refraction, although as a matter of practical convenience it is found necessary. This being premised, i t is of little moment that the atomic refrac- tions now given differ from those previously employed; those in Table VI answer well for a large number of substances of fairly similar types, namely, metallic salts, but when accurate data sha 1 have been compiled from measurements made on large numbers of compounds of widely different types, doubtless the atomic refrac- tions in Table VI whilst undergoing multiplication will also have to undergo some revision.At the same time the list is sufficiently accurate to substantiate my view that the molecular refractions of solid salts are, in the main, the sums of definite so-called atomic or equivalent refractions. It should perhaps be pointed out that Mallard (Trait6 de Cristal- lographie, 1884, 2, 490) has giren a table of refraction constants of various oxides which may be used for calculating the molecular refractions of a number of minerals, more especially of silicates. This branch of the subject has, however, apparently not been further developed. The immense progress which has been made during the past half century in organic chemistry has been almost wholly due to the comparative ease with which methods, both physical and chemical, of determining molecular constit.ution have been devised. Similarly, the fact that so little is yet known of the constitution of inorganic compounds is in great measure due to the diEiculty of attacking such substances without profoundly altering them ; the peculiar action of water, usually the only available solvent, on them, and the infusibility and sparing solubility of most inorganic compounds, also increase the difficulty of determining their constitutions. The r e d t is that amongst inorganic compounds practically no chemi-1546 LAPWORTH AND KIPPING : cal means of determining constitution are available, inasmuch a3 the substances must of necessity be examined in the solid state. Almost the only applicable methods of arriving at the constitution of inorganic compounds are thus necessarily physical ones, and, as is well known, such methods have not as yet been applied to any great extent to solid substances. The use of so highly constitutive a property as that of molecular refraction in the study of inorganic compounds may thus be expected to throw much light on the consti- tution of such complex subst'ances, for example, a8 the salts of tung- stic, molybdic and phosphoric acids. Chemical Department, Central Techizical College, South Kensington, Londost.

ISSN:0368-1645    

DOI:10.1039/CT8966901530

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

1546 LAPWORTH AND KIPPING : C I I.-Dei-ivati rcs of Ca mphene-su7phonic acids. By AR'rHUR LAPWORTH, D.Sc., and FREDERIC STANLEY KIPPING, Ph.D., D.Sc. AMONG the many changes which camphor undergoes, one of the most interesting is its conversion into acetylortho-xylene [2Me : Ao = 1 : 2 : 41 by concentrated sulphuric acid ; aud, although this reaction may be expressed by the simple equation CioHiGO + 2 0 = CioHiZO + 2H20, there can be no doubt that the change is a very complex one, and that oxidation is accompanied by a profound molecular rearrange- ment. Partly in the hope of obtaining some product, the study of which might throw light on this curious reaction, and partly in order to t r y to obtain sulphonic derivatives of camphor, an investigation of the behaviour of camphor towards sulphuric acid under various con- ditions was commenced several years ago, and it was then ascertained that camphor is vigorously attacked by anhydrosulphuric acid at ordinary temperatures, giving, amongst other products, a mixture of optically isomeric camphorsulphonic acids (Trans., 1893, 63, 548).The isolation of these compounds directly from the crnde product being impracticable, i t was necessary, in the first place, to convert uhe acids into the corresponding sulplionic chlorides by treating t'he mixture of sodium salts with phosphorus pentachloride in the usual manner. Dextrorotatory camph orsulphonic chloride and nn optically illactive modification of this compound, were then separated in a crystalline condition from the oily product thus obtained, but a veryDERIVATIVES OF CAMPHENE-SVLPHONIC ACIDS.1547 considerable proportion of the prodnct refused to crystallisc, and was not further investigated at the time. The probability that the constituents of this residue might be derived from intermediate products in the conversion of camphor into acetylortho-xylene, or from substances resulting from the partial breakdown of camphoy, has induced us to take up the examination oE this oil again, in spite of its uninviting character ; it is a record of this work whicb. we now communicate. The original oily mixture of sulphonic chlorides, prepared from the crude prodnct of the sulphonation of camphor in the mannei' previously described (Zoc. cit., pp. 549-552), contains, and apparently consists en tirelg of, four well-defined, crystalline compounds-namely, the dex trorotatory and optically inactive carnphorsulphonic chlorides which were formerly kolated, and two optically inactive sulphonic chlorides of the composition CloHl4C1*SO2C1, which we propose to name u- and p-chlorocampheneszLl~~~nic chloride rcspectively.These names are assigned to the two optically inactive isomerides mainly because their molecular composition indicates that they are derived from a chlorocamphene, and because the conditions under which they are formed froin camphor are, doubtless, such as might a t the same time bricg about the transformation of camphor into chlorocamphene. When camphor is submitted to the action of phosphorus pentachloride, it gives, as is well known, a dichloride cf the composition C,,H,,C12, which is changed to camphcne by the action of sodium on its ethereal solution; if, however, this dichloride be heated alone, or with quinoline (Marsh and Gardner, Proc., 1894, 57), it loses the elements of bydrogen chloride, and is converted into chlorocam phcne.It seemed very probable, therefore, t>hat the action of excess of phosphorus pentachloride c n the sodium salt of camphorsulphonic acid might bring about not mcrely the formation of the sulphonic chloride in a normal manner, butl also tbat of an unstable dichIoro- sulphonic chloride, which might then lose the elements of hydrogen chloride. NaO+332-C,H,,<?H2+ Cl-S0,~C,Hl,<~H2 - Cl-SO,~C,H,,< CH i I co c c1, cc1' A compound formed in t'his way from an optically inactive 01- racemic camphorsulphonic acid, by reactions analogous to those which are known to occur in the case of camphor, would have the composi- tion of the isomeric sulphonic chlorides in question, and would be derived from EL chlorocamphene identical or isomeric with thak referred to above ; the names which we have given to the two new compounds seem, therefore, to be appropriate.The fact that two isomeric, optically inactive chlorocamphexie-1548 LA PKORTH AND RIPPING : sulphonic chlorides are obtained under the above conditions is capable of several interpretations, but, in absence of facts, little would be p i n e d by discussing the relation between the iwo. The study of the properties of the two isonierides confirms the vicw that they arc derivatives of camphenc ; having fully established their coinposition by the preparation and analysis of the correspond- ing amides, we made attempts to oxidise or otherwise break clown some of the various componnds.These experiments, however, were a11 unsuccessful owing to the great stability of the substances, in which respect they show a marked relation to camphene, and behave, indeed, as might be expected of camphcne derivatives. In r;pite of the lack of success which has just been mentioned, several interesting facts have been established during the inrestiga- tion. Thus a-chlorocamphenesulphonic chloride exists in t RO definite physical modifications, both of which have been examined crystallographically, arid differ in melting point by only 4'; the melting point of the P-sulphonic chloride is the same as that of one of the modifications of the a-compound, but the crystals a.re not suitable for goniometrical measurement.Both compounds are so slowly hydrolysed by hoiling water, and are so readily volatile, that they may be distilled in a current of steqni without any very large qumtit-y being decomposed--n behaviour rarely met with in the case of sulphonic chlorides generally ; even more remarkable, however, is the fact that the decomposition of the a-compound by water at moderately high temperatures yields not only the corresponding u-chlorocan~phenesulp~onic acid, CloHliCl*S03H, by interaction with water in the normal manner, but also a dichlorocnmphene, which is formed in accordance with the equation C,oH,,CI*SO2Cl = CI,,HI,CI, + SO?.The latter change occurs almost quantitatively when the sulphonk chloride is heated with water at EO', and is, we believe, the first case in which such a decomFosition has been observed undcr the given conditions. a-Dichlcrocamphene is also formed when the a-sulphonic chloride is heated alone at 160-1€0', a behaviour which is analogons to that of many of the sulphonic chlorides and bromides of camphor, and which seems to be especially characteristic of snlphonic derivatives containing the group -CH,*S02X (X = C1 or Br). a-Dichloro- camphene is chiefly remarkable on account of its great stability ; i t crysiallises in needles and is very volatile, its vapours having a strong, rather pleasant, smell. 6-C hlorocamphenesnlphonic chloride is hydrolysed by boiling water, but only extremely slowly; the action in t h i s case takes the ordinaryDERIVATIVES OF CAMPHENE-SULPHOKIC ACIDS. 1549 course, the corresponding sulphonic acid being formed.Tbo decom- position which the P-sulphonic chloride undergoes when heated alone seems, however, to bc analogous to that of the a-compound, inas- much as sulphur dioxide is evolved, and a volatile, neutral oil is produced ; as a considerable qnantity of tarry matter is also formed, and the yield of P-dichlorocamphene is comparatively poor, we did not prepare the latter in quantity sufficient for a thcrough examination. ~ - C h l o r o c a ~ n ~ h e n e s u ~ ~ o ~ i c acid, CloH14C1*S03H, which, like the isomeric a-cornpound, shows all the ordinary properties of substances of this class, undergoes a curious intramolecular change when it is warmed with mineral acids, being transformed into a neutral snb- stance insoluble in water ; the nature of this isomeride has not been definitely established, but it seems probable that it is a SdphoZnctone, C,,H,,CI<i> , derived from a saturated hydrocarbon (cnmnphan) of the composition CloH18.It is well known that certain unsaturated acids of the type >C:CH*[CH,],,-COOH (n = 1 o r 2) are converted into saturated lactones of the type >C*CH,*CH,*YO I o r >CH*CH*CH,.CH,*$lO by intramolecular change, either on distillation or under the influence of mineral acids, and, as p-chlorocamphenesulphonic acid probably con- tains an unsaturated group, >C:&[$].*CH,-SO,H ; i t seems likely that a similar intramolecular change may occur, a lactone containing the complex >CH*&*[hln*CH2*SO2 I being formed.s 0 2 I 0 1 0 I-.-- 0 The properties of the neutral substance are conformable with this view of its character, and, therefore, for the sake of reference we name the compound ~-shlorocanipl~ansulpliolactone. EXPERIMENTAL PART. The yellow oil, obtained by the action of phosphorus pentachloride on the mixture of sodium salts of the sulphonic acids produced by the sulphonation of camphor, constituted the raw material for this investigation. This oil is repeatedly extracted with light petr- oleum, atl first a t ordinary temperatures with petroleum boiling at 20-30°, and subsequently at higher and higher temperaturas with various fractions of petroleum boiling a t temperatures rising to about llOo.Iu this way a very rough separation of the four con- stituents of the mixture is effected ; the camphorsnlphonic chlorides, particularly the optically active modification, ara, when purified, much more sparingly soluble than the chlorocamphene derivatives,1550 LAPWORTH AND KIPPING : mid are, therefore, contained in the later extracts, froni which they are deposited in a crystalline condition, almost entirely free from the more soluble camphene compounds. The solutions, from which the crystals of camphorsuIphonic chlorides have been separated, yield, on spontaneous evaporation, first, fnrthev quantities of crys tallinc materia1, and then a deposit of a yellow oil ; the crystalline products, consisting of mixtures of varying proportions of sulphonic chlorides of camphor and of chlorocamphene, vary considerably in character ; they are collected in such a way that those of similar appearance are brought together.The yellow oil, deposited from the later extracts, is then fractionally extracted with petroleum in the same way as before, and is thus separated into one or two crystalline por- tions (which are added t o those of similar appeamnce already obtained), and a portion which remains liquid. These liquid portions are mixed with the large deposits of oil which separate (dmost free from crystals) from the first extracts of the original crude prodnct, and the whole is ngnin systematically extractcd as before until the solutions cease to yield any crystalline material when left undis- turbed for a few days.The various petroleum solutions are then allowed to evaporate, and the oily residues placed aside in a cool place ; during the minter months the oils gradually solidify, and the crystalline material is then separated with the aid of the filter pump, and spread on porous porcelain. I n this way practically the whole of t h e original product is eventually obtained in a crystalline condition. The final separation of the four sulphonic chlorides is accomplished by taking the various crystalline fractions which have been collected, and submitting them to fractional crystallisation from light petr- oleum ; a detailed description of this tedious and troublesome process would not be of rery much yalue, because the operator must judge more from the appearance and melting-point of each deposit than from its mere solubility. It may be noted, however, that various fractions of light petroleum (b.p. 20--30°, 40-50°, and 70-80") must be used in order to effect the desired separation ; further, that, although the purified comphor.;dphonic chlorides are much mere sparingly soluble than the camphene compounds, they are frequently met with in the most soluble fractions, even after repeated crystalli- sation. As soon as the camphor compounds have been to a great, extent freed from the chlorocamphene derivatires, a little ether added to the petroleum aids the final separation ; fhera is, in fact, very little difficulty in isolating the camphorsnlphonic chlorides, but the separation of the two camphene compounds is much more troublesome, partly owing to their being frequently deposited in an oily state, especially in presence of a trace of camphorsulphonic chloride, partly owing to their great solubility in the only solvent which can well be used. Finally,DERIVATIVES OF CAMPHENE-SULPHONIC ACIDS.15 31 however, two main fractions are obtained, one being the a-compound in the form of small nodular crystals melting at about 84', the other, the isomeride, in large, transparent plates melting at about 75'. The former is practically pure ; the latter, however, cannot apparently be obtained from petroleum in a pure state, and must, therefore, be purified by one or two crystallisations from methylic alcohol, whereby it is obtained in long, transparent needles, which melt at practically thc same temperature as the massive crystals of the a-compound, namely, at 83-84". a- Chlorocam23ltenesulphonic Chloride, CloH14C1*S02Cl.a-Chlorocamphenesulphonic chloride is one of the principal COE- stituents of the original crude oil, whereas the @-compound is present in comparatively small quantities. Having been separated in the manner already described, it may be further purified by a final crystallisation from a mixture of benzene and petroleum. A specimen prepared in this manner, and melting at 83-84', was analysed witth the following result : C = 45.23 ; H = 5-38. 0.1759 gave 0.2919 CO, and 0.0852 H,O. CloH14C1*S02Cl requires C = 44.7; H = 5.2 per cent. a-C blorocamphenesulphonic chloride separates from cold, light petroleum, chloroform, o r benzene, in the form of beautiful trans- pnrcnt crystals, which melt at 83-84"; if fused and allowed to solidify, it melts at 87-88", a probable indication of dimorphism.It is extremely soluble in benzene, chloroform, acetic acid, sthylic acetate, acetone, and ether, and it dissolves very readily also in hot,, light petroleurn (b. p. = 60-70'), but is much less soluble in the cold liquid ; in methylic alcohol it is somewhat sparingly solnhle, being dissolved rather freely by the hot liquid, but separating, for the most part, as the solution cools. When heated with water, i t sinks as an oil, but a small quantity passes into solution ; on cooling, i t is first deposited as an oil, finally separating in the form of long, semi-transparent needles ; it maly be boiled with water during several days without undergoing hydrolysis to any considerable extent.I t rolatilises to some extent in aqueous vapour, and, when very impure, may be obtained in a crystalline state by subjecting it to distillation in steam; at the same time, however, a minute amount undergoes decomposition into sulphur dioxide and dichlorocamphene. When heated with water in sealed tubes a t 120', it is almost entirely con- verted into dichlorocamphene. It is very rapidly hjdrolysed when heated with solutions of soluble metallic hydroxides, a metallic chloride and a chlorocamphenesnlphonate being produced. a-Chlorocamphenesnlp honic chloride, like t,he sulphonic chloride of a-bromocamphor, is exceedingly stable towards ordinary oxidising1552 LAPWORTII AND KIPPING : agents; i t may be boiled with nitric acid (sp.gr. = 1.4) during several minutes, and be subsequently recorered practically unchanged. When boiled with fuming nitric acicl, however, i t is slowly acted on, nitrous fumes and chlorine being evolved, whilst a marked oclour of chloropicrin is perceptible ; after several hours boiiing, the action becomes distinctly less rapid, and if the liquid at this point be diIuted and evaporated on the water bath, precaution being taken to get rid of all nitric and sulphuric acids, the oily mixture on dilution deposits a srriall quantity of a substance insoluble in water ; but the oils, how- ever treated, do not evince the slightest tendency to crystallise ; they consist, doubtless, of snlphonic acids, as very little sulphuric acid is formed during the oxidation, and i t is probable that the substance insoluble in water is a sulpholactone analogous to that obtained by us on oxidising ammonium bromocamphorsulphonate with nitric acid (Proc., 1896, 77).I n the hope of obtaining derivatires of the sulphonic chloride con- taining more halogen, we have investigated the action of bromine on the compound. On mixing a solution of the chloride in chloroform with bromine, it is coloured yellow, but the colour gradually dis- appears, hyqrogen bromide being evolved. The liquid, on evaporation, deposits a colourless oil, from which we have not succeeded in obtain- ing any crystalline matter. Similar experimeuts made with solutions of the substance in petroleum and ether proved equally fruitless.The crystallographic properties of a-chlorocamphenea ulp honic chloride were carefully studied, the behavioor, on fusion, of the crystals deposited from petroleum, &c., having indicated that the substance is dimorphons. Repeated endeavours were made to isolate the two modifications by crystallising the substance from various solrents under diverse conditions, and it was thus discovered that, although in almost every case the crystais obtained belonged to the anorthic system, and melted at 83-84", yet when crystallised from hot methylic alcohol the chloride separated in comparatively simple crystals, obviously different in type from those obtained in other wajs. They were of orthorhornbic sjmmetry, and melted at 87--8S0. The t w o forms were submitted to a somewhat detailed examination, and the following data were obtained.The first modification, melting at 83-84", is deposited from solu- tions of the sulphonic chloride in acetone, ethylic ace Me, ether, benzene, chloroform, light petroleum, or cold methylic alcohol. Crystals obtained from petroleum or chloroform consist of magnifi- cent, transparent, anorthic prisms with a calcite-like lustre ; t,hose from cold meihylic alcohol form plates, which, although they bear no obvious resemblance to the foregoing, j e t are found, on measure- ment, to bc derived from the same forms.DERIfhTIVES OF CAMPHENE-SCJLPHONIC ACIDS. 1553 Crystalline System : Anorthic. u : b : c = 0.6668 : 1 : 0.8396. a = 79" 46', p = 96" 32', "1 = 88" 5'. Forms observed : a ( i ~ ~ ) , b(oio), c(ooi), ppio), q(o2i), o ( l i i ) , or(iii.).F I G . 1. FIQ. 2. The following angular measurements were obtaiued : No. of Angle. measurements. Limits. Mean. Calculatcd. 26 41" 19'- 41' 59' 41' 48' - np = 100 : 110 QO = 100: iii oto = 111 : 111 19 '73 24- '74 32 73 67 73 53 = Iii : 100 48 34 - 18 48 46- 49 35 49 13 - 18 56 26- 57 29 56 59 - ph = 110: 010 26 43 10- 48 51 ba = 010: loo 24 89 4- 90 5 89 38 89" 38' ac = 100: 001 4 69 13- 70 8 69 41 69 51.5 cp = loo: 110 12 81 0- 81 58 81 34 81 30 = ooi : ioo 4 110 22-110 45 110 34 110 8 . 5 43 26 - 130 = 3.19: 111 14 45 57- 49 51 oc = iii: OOI 12 48 28- 49 32 49 10 49 4 C d - 001 : I1I 4 125 39-126 11 125 5& 125 57 otC = iii : ooi 4 53 42- 54 a 53 54 54 3 bo = 010 : I1I 4 75 43- 76 36 76 16 76 4 ho' = 010 : ili 7 73 50- 74 46 74 10 74 3.5 bp = 010: 021 3 43 35- 44 23 44 0 43 41 = iii : 010 4 103 31-104 1 103 44 103 56 o'b = iii : oio 7 105 23-106 12 10.5 50 105 56.5 cL = 001 : 010 8 69 13- 70 8 69 48 69 51 qc = 021 : ooi 3 65 59- 65 52 66 35 66 25 pq = 110: OZI 6 5'7 25- 57 59 57 41 57 31 qof = 021 : iii 8 45 13- 45 53 45 31 45 31 otP = iiI : i i o 8 76 29- $7 2 76 54 76 58 The crystals obtained from solutions of the sulphonic chloride in chloroform or petroleum crystallise in the more massive habit depicted1554 LAPWORTH AND KIPPING : in Fig.1, whilst those cbtained from cold metbylic alcohol assume the plate-like form of Fig. 2. The measurements obtained from the former were not so concordant as those from the latter, owing to the sub- stance being more readily soluble in chloroform and benzene than in methylic alcohol, re-solution, therefore, taking place more freely i n the former instance.In the prismatic crystals (Fig. l), the forms n(100), b(010), and c(OO1) are most strongly developed, the last- mentioned being almost invariably the largeut on the crystal ; the form a( 100) is usually corroded, and gives exceedingly poor images ; m{111) and o(I11) are usually discernible and give good reflections, whilst q(O2l) has been noticed only on two crystals, one face of the form being present in both cases. In the plate-like crystals, the predominating form is p(llO), which is always bright and gives excellent images; of the other forms b(010) and q(O%) are always present, whilst the pinncoid ~(001) occurs but seldom, and, as in the case of the prismatic crystals, is usually deeply corroded. There does not appear to be any definite cleavage, although slices may occasionally be separated approximately parallel to the three pinacoiids a(100), b(010), and ci001).The acute optic axial bisectrix appears t o emerge somewhere in the angle between b(010) and p(110), but owing to the brittle nature of the crystals the orientation of the axial plane could not be determined with any certainty. The axial angle is wide ; the double refraction is rather strong and negative in sign. The dispersion is strong. The second modification of a-chlorocamphenesulplionic chloride is obtained when the modification just described is melted and allowed to cool. It is also obtained, as has already been mentioned, when the sulphonic chloride is crystallised from hot methylic alcohol, and then forms brilliant, transparent tables or pyramids, which melt at 87-89', and remelt at the same temperature, When allowed to remain, eithci- in the solvent or in the open air, they are seen to develop white patches, which are sharply defined from the transparent portion ; these patches, in a few days, extend through the whole mass of the crystal, renderiag it quite opaque, and the crystal then melts at 83-84', thus showing that the opacity is caused by a reversion of the substance or the crystal to the first or anorthic modification. The crystals lend themselves very well to goniometrical examina- lion, and thc following are the results which have bcen thus obtained : Crystalline System : Orthorhombic.a : b : c = 0.9030 : 1 : 0.9358. Forms observed : a{100), b(010), ~(lll), and ~ ( 1 1 0 ) .DERIVATIVES OF CAMPHENE-SULPHONIC ACIDS. 1 555 FIG. 3, Thc following angular measurements mere obtained : No. of Angle. observations. Limits. Mean. t o 2- 010 : 111 32 56’ 45’- 5i0 10’ 56” 59’ 00 = 111 : 111 1G 65 51- 66 28 66 4 PO = 110: 111 20 35 15- 35 54 35 37 00 = 111 : 111 1 G 108 29-109 19 108 45 t r = 110: 010 25 47 46- 47 67 47 50 ~rp = 100: 110 22 4L 54- 43 17 42 8 00 = 100 : 111 6 52 40- 53 3 52 54 PO = 111 : iii 4 74 1 - 74 26 74 9 bn = 010 : 100 16 89 49- 93 7 93 2 ob = 100: oio 16 89 51- 90 7 89 57 Calculated. 66” 2’ 108 4G 47 55 42 5 52 54 74 13 90 0 90 0 - - The crystals, as a rule, are unsymmetrically developed tables or pyramids, with brilliant faces ; the latter yield fairly good images, even when the crystals have become quite opaque owing to rever- sion to the anorthic modification.The form o(ll1) is usually the largest, but is sometimes reduced t o a mere strip; in the latter instance, t( 0101, usually small, becomes the predominating form ; a(100)) is invariably small, but yields perfect images, as do the forms ~(110) and b(010). The reflect’ions from o ( l l 1 ) are rather poor. There is no definite cleavage. The acute bisectrix emerges parallel to the axis 6, the optic axial plane being c(OG1). The double refraction is positive and fairly strong, the optic axial angle being rather wide. The dispersion is slight. a- Clr. iorocamphenesulphonamide, CloE14C1.S0,*NL12.I n order to prepare the amide, the sulphonic chloride is finely powdered and added to about 10 times its weight of strong aqueous ammonia containcd in a stoppered bottle, and the whole vigorously shaken ; after a short time the powder seems to suddenly change in crystalline form, becoming much mcwe bulky, but no development o€ heat is noticeable. At the end oE about four hours, the liquid and1556 LAPWORTH AND KIPPING : crystals are transferred to an evaporating basin, the ammonia allowed to evaporate, and the crystals separated and washed with cold water; the residue is finally crystallised from dilute alcohol and dried at 100'. 0.1669 gave 0.2975 CO, and 0.1015 H,O. C = 48.6; H = 6.76. 0.1593 ,, 0.2817 ,, ,, 0.0955 ,, C = 48.2 ; H = 6.66.C,oH14Cl*S02*NH2 requires C = 49-12 ; H = 6-43 per cent. a-Chlorocamphenesulphonnmide is readily soluble in alcohol, ether, acetone, and ethylic acetate, somewhat less readily in cold benzene, and only sparingly in chloroform, petrolenm, and water. It is dis- solved by dilute alkalis, and is reprxipitated on the addition of acids. It crystallises from nearly all solvents in thin plates with a satiny liistre, but from its solution in chlomform i t is precipitated by light petrolenm in the form of feathery, skeleton-like forms. It is probable that this subst.ance is dimorphous, as on one occasion i t was found to fuse sharply at aboutl 135O, and then to solidify imme- diately, melting once more at 161--162O, its usual melting point ; after solidifying, it melts at the latter temperature.The crystals deposited from the alcoholic solution on spontaneous eraporat ion are small rhomboidal plates truncated at their acute a,ngle. The extinctions in polarised light bisect the angles of the rhomb, and under convergent polarised light the large face of the crystal is seen to be perpendicular to an optical bisectrix, probably the acute. The crystals are therefore orthorhombic, the large face being a pinacoid (100) cut off by the four faces of the dome (0111, which make an angle of about 79" with one another, and are trun- cated at the acute angle by the form (001). When melted upon a microscope slide under a cover glass, the amide solidities in arbore- scent forms, which lie perpendicular to the bisectrix seen in the crys- tals above mentioned.The axial mgle is large, the doubIe refraction being very weak and positive in sign. Hoping to obtain the corresponding derivatives of camplrene by the reduction of chlorocamphenesulphonic acid derivatives, and regarding the amide as the most suitable compound with which to experiment, we have closely examined its behaviour towards reducing agents, but without success. It is not changed when its alkaline solu- tion is heated during several days with a large excess of sodium amalgam; it also resists the actionof zinc dust and ammonia at looo. The stability of the chlorine atom in presence oE alkalis is also very remarkable ; the amide, when heated for several hours with boiling strong soda-lye prepared from the metal, does not gire a detectable quantity of sodium chloride.The dispersion is slight.DERIVATIVES OF CAMPHENE-SULPEONIC ACIDS. 15.57 a- Chlorocampheneszl~hanilide, C,oR,,C1*SO,*NH.C,H,. When a-chlorocamphenesulphonic chloride is heated with aniline for a, short time on the water bath, it gives a dark browu product, from which it is somewhat difficult to isolate the anilide. If, haw- ever, the sulphonic chloride and aniline are dissolved together in ether, and the solution is allowed to remain in a stoppered bottle during three or four days, aniline hydrochloride is deposited in con- siderable amouut, and only a slight discoloration ensues. The anilidc is easily obtained h o r n the praduct by evaporating the et.her at ordinary temperatures, washing the residue with dilute hydrochloric acid and water successively, and then crystallking i t twice from dilute alcohol.An analysis of this compound was deemed unneccs- sarg, but it was proved to contaiu chlorine by qualitative tests. a-Chlorocamphenesulphanilide dissolves readily in alcohol, ethy lic acetate, arid acetone, but is rather less soluble in ether and chloro- form, and dissolves only with difficulty in benzene ; it appears to be insoluble in light petroleum and i n water. When slowly heated, it, begins to darken a t about 810°, arid melts at 234", but when the capillary tube is plunged into sulphuric acid at 2 3 4 O , the anilide remains solid up to about 237'. It crystallises from hot methylic alcohol in long, beautiful, colour- less, striated plates, their ends being obliquely truncated at about 45O ; they probably belong t o the anorthic system.When examined i n polarised light, the errtinctions make angles oE abont 5 5 O with the sides of the plate. Examined under a 2%'' immersion objective iu convergent polarised light, an optic axis is seen to emerge at the edge of t,he field, corresponding with the direction of greatest Icngth. of the crystal ; the double refraction is weak. a- Ch lorocamphenes.ltl~)?honic acid, C,oH,,Cl*S 0,H. As has already been mentioned, a-chlorocamphenesulphonic chloride exhibits great stability towards boiling water, and even after boiling with a large excess of water during a week only a small proportion undergoes hydrolysis ; decomposition may be hastenkd by carrying out the process in sealed tubes in toluene vapour, but under these conditions a large quantity of dichloro- camphena is formed.The best way to prepare the acid is to heat the sulphonic chloride with SL solution of barium hydroxide, lvhich produces almost instantanems hydrolysis without causing the re- moval of the second chlorine atom ; the barium in solution is then precipitated by the careful addition of sulphuric acid, and the filtered solution of the sulphonic acid is repeatedly evaporated until free from hydrochloric acid. VOL. LXIX. 5 N1558 LAPWORTH AND KIPPLNGI : When the syrup finally obtained is kept in a desiccator, it grada- ally sets t o a mass of thin plates, which appear t o contain water of crystallisation ; after hrtring been sprenl on porous earthenware oyer sulphuric acid and then dried at 100' until constant in weight,, i t may be further purified by crystallisation from hot benzene, from which i t is deposited in small plates.a- Chlorocamphenesulphonic acid dissolves very readily in water and alcohol, and is also somewhat readily soluble i n ethylic acetate, acetone, chloroform, and hot benzene ; it dissolves somewhat sparingly in ether, and appears t o be quits insoluble in light petro- leum. Its aqueous solution has a bitter, somewhat astringant, taste, and dissolves zinc readily, evolving hydrogen. When the anhydrous acid is slowiy heated, it gradually becomes dark brown, and a t 264-265' swells up considerably, evolving gases, amongst which sulphurous nnhFdride is perceptible by its odour, finally forming a fairly limpid liquid. The crystals deposited from hot benzene are beau- tiful, small, elongated, glistening plates of ill-defined outline ; on examination in polarised light, they usually show very brilliant interference colours, and, in convergent light, some individuals show an optic axis emerging perpendicularly. The optic axial angle is fairly large, and the double refraction is strong whilst the dispersion is rather slight.The following metallic salts of the acid were prepared from the latter by neutralising its aqueous solution with the corresponding me taliic carbonates. Potassium a-cli ~oroca~nphe,aesulpholzate crystallises from water in .small, well-defined, elongated, orthorhombic prisms showing the forms (loo), (LIO), and (111). The small size of the crystals made it impossible to determine their optical properties.The subst,ance dissolves readily in water, and is precipitated by strong potash, it is nearly insoluble in acetone and in strong alcohol. Sodium a-chZorocamphenesulphonate crystallises from hot water in ill-defined plates, but is obtained in well-defined pyramidal crystals on allowing the aqueous solution to evaporate spontaneously. It is insoluble in acetone, but dissolves slightly in strong alcohol. The double refraction is very weak. Attempts were made to cause the separation of the sulphonic group from a-chlorocamphenesulphonic acid by heating it a t high temperatnreu with hydrochloric or sulphuric acid. In every case it was found that, where partial hydrolysis had occurred, the prodnct had at once carbonised, and nothing but unaltered acid and a charcoal- like mass could be obtained.DERIVATIVES OF CAMPHENE-SULPROXIC ACIDS.1559 a-Dichhrocamphene, C,,K,,CI,. The study of the decomposition products of the sulphonic chlorides and bromides of camphor derivatives, more especially in the case of ar-dibromocamphor, having yielded such interesting results, the effect of heating a-chlorocamphenesulphonic chloride was carefully investigated in the hope of eliminating sulphurous anhydride, and thus obtaining a dichlorocamphene which might serve as the start- ing point for further experiments. It was found that a-chlorocamphenesulphonic chloride does, in fact, undergo decomposition at elevated temperatures, and that the change is analogous t o that which occurs in the case of the camphor derivatives p~eviously studied, the products being cc-dichlorocam- phene and sulphur dioxide a-Dichlorocamphene may be prepared by simply distilling the puri- fied camphenesulphonic chloride, but, as the distillate is usually con- faminated with unaltered snlphonic chloride it is better to keep the temperature at 160--180° until the evolution of sulphur dioxide is at an end ; the brownish liquid residue is then distilled, and the crys- talline product purified by crystallisation from alcohol.A less impure product is obtained if t.he sulphonic chloride is heated at a temperature of 130-140°, with about five times its weight of water, for about 48 hours. Although, under these con- ditions a small quantity of tho snlphonic chloride is converted into the sulphonic acid, yet the greater part suffers the above-described decomposition, and the a-dichlorocamphene, after distillation with steam, is obtained practically free from impurity.A sample which had been recrystallised from alcohol and dried over sulphuric acid gave the following results on analysis : 0.1495 gave 0.3212 CO, and 0.0959 H20. C = 58-59; H = 7-13. 0.1956 ,, 0.2710 AgC1. C1 = 34.2. C~,,HlaC12 requires C = 58.61; H = 6.84; C1 = 34.67 per cent. a-Dichlorocamphene is excessively soluble in light petrdleum, benzene, ethylic acetate and acetone, but less readily in methylic and ethylic alcohols, and nearly insoluble in water. I t is deposited from a cold solution in rnethylic alcahol as beautiful, t.raasparent needles or prisms, whose sides are composed of lustrous faces, but whose terminations appear as if broken off, so that their gonio- metrical examination was useless ; from dilute alcohol it crystallises in curious fern-like forms which are made up of aggregations of fine needles. It melts at 72-73', sublimes readily when heated alone, 5 ~ 21560 LAPWORTH AND KlPPING : and is excesaively volatile in aqueous vapour ; its odour is remark- ably powerful, and i s reminiscent of fresh india-rubber.When a solution of a-dichlorocamphene in acetic acid is heated with a large exce.w of zinc dust, frae from halogen, it appears to snffer decomposition, as, after d.lution and filtration, the solution gives a distinct precipitate with silver nitrate; the quantity 80 reduced, however, must b3 very small, as the substance precipitated G n dilntion melts only a few degrees below the melting point of the pure compound, and is easily shown to be unaltered dichlorocam- phene.All other attempts to effect its reduction proved equally futile. The substancs in acetic a2id solution does not appear t o be oxi- dised by cold potassium psrmanganate, and when heated with aqueous oxidising agentq, such as nitric acid, i t sublimes almost im- mediately, thus escaping oxidation ; in all respwts it was found to be an extremely stable substance, and for these reasons its study was n ~ t carried farther, p- Ch lorocamphmesulpho,z ic Chloride, CIoHI,Cl.S 0,Cl. The impure /3-chlorocamphenesulpEonic chloride (m. p. abou t 75'1, separated from its isomeride in the manner already described, was purified by repeated crystallisation from light petroleum (b.p. 30- 40°), and was thus obtaified in large plates melting a t 77-7s"; as this preparation seemed to be homogeneous, and its melting point did not alter on further crystallisation from light petroleum, a sample mas analysed, with the following resuIts. 0,1532 gave 0.2529 CO, and OsOS20 H,O. C,oH,4Cl*SOzC1 requires C = 49-66 ; H = 5 21 per cent. Although this analysis, no doubt, correctly represents the composi- tion of the substance, all specimens purified in the above manner are still slightly impure, an3 the melting point given in the preliminary notice (77-78') u-as on this account somewhat too low, since, by using a solvent such as metbylic alcohol, in which the two chlorides are more nearly equally solubk, the meltiug point of the ,+suIphonic chlolide may be finally raised to 83-84', which is the same as that of the ordinary form of the a-sulphonic chloride.P-C hlorocamphenesulphonic chloride does not appear to be dimorph- ous like the a-compound, although i t assumes two habits entirely dit€erent in appearance ; from light petroleum it is deposited in large, transparent plates, which become white and opaque on exposure to the air, or when gently heated in contact with the supernatant solution ; fwm hot mzthylic alcaliol it crystsllises in beautiful, long, trans- paraat needles, which completely traverse the mother liquor, being C = 45.02 ; H = 5 94.DERIVATIVES OF CAMPHENE-SULPHONIC ACIDS. I 561 usually terminated only by the Fides of the containing vessel. These needles belong to the tetragonal system ; a thin transverse section of one of them, when observed i n convergent polarised light, is found ta be perpendicular to the optic axis of a uniaxial figure ; the same appearance is observed when a small quantity of the substance is allowed to solidify between glass plates, when the compound crystal- iises in fern-like forms, whose appearance is indistinguishable from ammonium chloride, all the branches making 90" with one another.The double refraction is strong and positive in sign. P-Chlorocnmphenesulphonic chloride is much more freely soluble in most solvents than its isomeiide, liquids, such as benzene, chloro- form, and ethylic acetate, dissolving it to an almost indefinite extent ; it is also readily soluble in cold light petroleum (b.p. = 25-4OO). As indicated above, however, it is somewhat sparingly soluble in cold methylic alcohol. It shows much the same stability as its isomeride towards various agents. It is scarcely affected by boiling water, and may be boiled with it during several days without undergoing much decomposition, but is almost instantaneously hydrolysed by boiling solutions of metallic hydroxides, yielding the corresponding sulphonates. It is readily volatile i n steam, and this fact may be taken advantage of i i i effecting the crystallisation of the lasb portions of crude oils, which contain large qaantities of the P-sulphonic chloride. It is slowly acted on by a solution of bromine in chloroform, but the product, as in the case of the isomeric chloride, is not readily purified, and has not yielded a trace of crystalline matter.Its beha- viour towards nitric acid also resembles that of its isorneride; the oxidation product, after elimination of nitric acid, yielded a small quantity of a colonrless substance, insoluble in water, but soluble in acetic acid, probably a sulpholactone, together with a large quantity of rion-crystalline matter, doubtless consisting of a mixture of snl- phonic acids. /3- Ch lorocamphenesuZpho)iamide, CloHlrC1*S02*NR2. This compound is prepared by treating the sulphonic chloride with cold aqueous ammonia in the usual wanner, and is readily purified by crystallisation from metbjlic alcohol, A specimen F'BS dried at loo3 and analysed. C = 48-11 ; H = 6.68. O.li12 gave 0.3020 GO, and 0.1014 H20.C oH14C1*S0zNH2 requires C = 48.12 ; H = 6.42 per cent. f3-Chlorocamphenesnlphonamide crystallises from cold alcohol or et hplicsacetate in curious, ill-defined, striated plates, which melt at 156-157" It differs considerably from its isomeride in regard t o its1562 LAPWORTH AND 3IPPlNG : solubility in various liquids; tbus, whilst the latter is only sparingly soluble in chloroform, the former dissolves readily ; the a-derivative appears to be insoluble in petroleum, whilst tthe &derivative is appx- ciably soluble. On adding petroleum to hot solutions of the two amides in chloroform, crystals are deposited, which are quite distinct, the a-sulphonamide giving flocculent aggregates of flat plates, and the /3-sulphonamide a precipitate of well-defined minute needles.The p-sulphonamide is readily soluble in cold ether and benzene, and dissolves sparingly in water, in all cases being more freely soluble than the isomeric substance. It crystallises from water in thin, striated plates. When melted upon a microscope slide beneath a cover glass, it solidifies in white, detached areas, which, on examina- tion under a A'' immersion objective in polarised light, show a biaxial interference figure exactly resembling that seen on subjecting the a-sulphonamide to similar treatment. The double refraction is positive in sign, and weak. p-C hlorocamphenesulphonamide is readily soluble in alkalis, and dissolves to some extent in aqueous ammonia, being precipitated in both instances on the addition of acid. It sublimes when gently heated in a test-tube, and solidifies in the form of striated plates resembling those from alcohol or hot water.This amide was sub- jected to the same series of experiments as was the isomeric substance, and showed the same great stability; thus the action of reducing agents was carefully investigated, and in all cases it was found that they failed to displace any appreciable quantity of halogen. Hydr- iodic acid a t 100" was found t o attack the substance, iodine bcing liberated, but the quantity of amide reduced was probably n o t estimable. The amide was also boiled during several hours with ib strong solution of pure potash, and here again tlie liquid: on rtcidifica- tion and filtration, gave only a faint precipitate on the addition of silver nitrate.p- Chlorocampheneszdp7~ aniZide, CloHIPCI*SO2*NH.C6Hj. /3-Chlorocamphenesulphonic chloride and aniline interact vigor- ously, and unless care be taken the anilide is associated with oily impurities, which render purification very t,edious ; the anilide is best prepared in the manner described in the case of the a-compoiind, the reddish oily product being purified by fractional precipitation from alcohol, and subsequent treatment with animal charcoal ; the filtered solution of the less highly coloured portions then deposits the anilide in moss-like aggregates, and, after recrystallisation from cold dilute methylic alcohol, the substance is practically pure. /3-Chlorocamphenesulphanilide is excessively soluble in ether,DERIVATlTES @F CAMPBENE-SULPHONIC ACIDS.1563 benzene, chloroform, acetone, acd ethylic acetate, but is rather less so in petroleum and alcohol ; it is slightly soluble even in water, and is deposited from the solution as a colourless oil, which gradually solidifies. It crystallises from dilute alcohol, on spontaneous evapo- ration, i n fern-like masses of beautiful plates melting a t 103-105°; from almost every other solvent, however, it separates as an oil. The very small size of the crystals put tbeir optical examination out of the question; if, however, the substance be solidified between glass slips, it shows in convergcnt polarised light a biaxial interference figure, whose bisectrix is perpendicular to the slide ; the axial anglc is rather wide, the double refraction being weak and positive in sign.p . Chlorocamphenesuly hoizic acid, CIoH,,C1* S03H. As /3-chlorocamphenesulphonic chloride is hydrolysed only with great difficulty by water; the sulphonic acid is most quickly pre- pared by boiling the chloride with baryta-water, in which it dissolves with great readiness. I f the solution of barium hydroxide be strong, the barium salt crystallises out and may be filtered off and purified. The solution of the sulphonic acid, prepared from that of the barium salt by cautious addition of sulphuric acid, is concentrated on the water bath, diluted with alcohol, and evaporated once more, these processes being frequently repeated. It is imperative, however, that the solution should never become very concentrated so long as any hydrochloric acid remains, otherwise the sulphonic acid is partially transformed into the insoluble substance described later, and partially into a black gummy liquid from which nothing crystalline can after- wards be isolated.When, however, the hydrochloric acid bas been expelled and the solution finally evaporated nearly to drgness, the whole is diluted and allowed to remain in a desiccator during a few days, when it sets to a mass of crystals imbedded in a syrup. The mass may then be spread upon porous earthenware, or it may be quickly triturated with a small qnantity of ethylic acetate and filtered, in eit-her case the sulphonic acid remnias behind and may be then purified by drying it a t 100' and crystallising from benzene. /3-Chlorocampheaesulphonic acid is excessiyely soluble in water, b u t is not very deliquescent in damp ail..It cqstallises from water in leaflets which appear to contain water d crystallisation, for they fuse below the true melting point of the substance, and at 120° evolve bubbles of gas, presumably water-vapour ; it is also readily soluble in ethey, ethylic acetate, and acetone, less readily in chloro- form and benzene, and moderately soluble in iight petroleum. When anhydrous, it crystallises from benzene o r ether in four-sided leaflets, whilst from its solution in petroleum it ie deposited, on1564 LAPWORTH AND KIPPING : cooling, in well-defined needles which appear to be crystallographi- cally identical with the leaflets. The anhydrous crystmalls melt, without decomposing, tit 78-79', and may be heated to 130° without being much discoloured o r decomposed; at about 1 4 2 O , however, there is a sudden disengagement of gases, among which sulphurous anhydride may readily be detected. The crystals, both the needle-like form from peti-olenm and the plate-like form from ether, appear to pertain to the monoclinic system, They are elongated, flat leaflets, the two longer sides being cut very obliquely by two others; the extinction is parallel to the longer side and the large face of the crystal is probably parallel to the optic axial plane.The characteristic property of this sulphonic acid is the readiness with which it changes in presence of strong hydrochloric acid into an isomeric substance insoluble in water. It forms a number of well- defined salts, of which the following have been examined. Potassium /3-chlorocarnphelzesulphonate may be prepared by neutral- ising the solution of sulphonic acid with potassium carbonate, evaporating nearly to dryness, and then allowing it to crystallise.It is sliglitly soluble in alcohol ; the crystals from its aqueous solu- tion are liquefied by acetone, but are not dissolved by it. If forms small, thin, four-sided rectangular plates which belong to the ortho- rhombic system, and the optic axial plane is parallel to the large face, the double refraction is very weak, its sign, however, could not be determined owing to the orientation of the axial plane. Sodium P-chlorocamphenesu Zplion ate, prepared in a similar manner, crystallises in very thin plates. I t is very solu'ble in water and in methylated spirit, but is insoluble in acetone.Barium p-chlorocamphenesu1phonate.-The preparation of this salt has already been described. When quickly crystallised from hot solutions, it separates in long, transparent needles, whilst on elow evaporation it is deposited as well-defined, elongated, six-sided plates. It is readily soluble in water, but insoluble in alcohol and acetone. The crystals belong to the orthorbombic system, the extinc- tion being parallel to the longer sides of the plates, and the optic axial plane parallel to the large face. The obtuse bisectrix is parallel to the longer side of the plate, the optic axial angle being small, the double refraction weak and positive; the dispersion is very weak. The double refraction is rather weak. When a solution of ~-ch~orocamphenesulphonic acid in hydro- chloric acid is evaporated to dryness it leaves a dark-coloured pastyDERIVATIVES OF CAMPHENE-SULPHONIC ACIDS.1565 mass, which, on trituration with water, affords some considerable proportion of an insoluble substance ; a further quantity of the same product may be obtained by repeating the evaporation of the soluble portion after addition of hydrochloric acid. If thrown on to a filter and washed with water, the compound gradually loses all colour, and finally forms a, ~ h i t e , ca,mphor-like mass which is best recrjstal- lised from methylic alcohol. A qualitative examination served to show that the substance con- tained chlorine and sulphur; a portion, which was dried over sul- phuric acid in a vacuum and then burnt, gave the following result : C = 48.04 ; H = 6.42. 0.3446 gave 0.2547 CO, and 0.0835 H,O. C1,HlaCIS03 requires C = 47.90 ; I3 = 5.99 per cent. /3- C hlorocamphenesulpholactonc dissolves very readily in acetone, ethylic acetate, chloroform, benzene, and ethylic alcohol, but is some- what sparingly soluble in cold methylic alcohol, and is not soluble to any appreciable extent iu water. It crjstallises from xnethylic alcohol in radiate tufts of minute needles, or in elongated plates, and, on application of pressure, aggregates in much the manner as camphor does. It melts at 183*5--184*5O, without decomposing, and, after solidifying, melts again a t the same temperature. The compound is insoluble in boiling sodium carbonate solution, but dissolves slowly in hot solutions of barium and potassium hydroxides ; its solution in barium hydroxide, after elimination of excess of barium by means of carbonic anhydride, and evaporation to dryness, yields a sticky barium salt which dissolves readily in water and alcohol, but which has not been obtained in a crystalline form ; the sulphonic acid prepared from this salt showed a similar disincli- nation t o crystallise, and did not yield the parent lactone by the action of hydrochloric acid. The lactone did not suffer any ap- preciable loss of halogen in undergoing hydrolysis with baryta or potash. /3- Chlorocamphenesulpholactone dissolves readily in hot aniline, but without apparent alteration, being almost entirely recovered on dissolving the base in bydrochloric acid. It is likewise unaffected by alcoholic ammonia or by cohobation with fuming hydrobromic acid during some hours. When warmed with hydriodic acid, a portion appears to undergo some slight. change as is manifested by the liberation of iodine, but the original substance was recovered almost completely a t the end of the operation. It is not more readily oxidised with nitric acid than is the parent /3-chlorocamphenesulphonic acid ; it dissolves in the hot liquid but without production of brown fumes even after prolonged heating ; on evnpcrat ion i t is once more obtained unchanged ; chlorine is not1566 PERKIN AND HUMMEL : THE COLOURIWO MATTERS liberated in this instance, as the addition of silver nitrate fails to cause any precipitate of silver chloride. Chemica 1 Department, Central Y’echnica 1 College, City and Guilds of London Ihstitute.

ISSN:0368-1645    

DOI:10.1039/CT8966901546

出版商:RSC    

年代:1896

数据来源: RSC

摘要:

1566 PERKIN AND HUMMEL : THE COLOURIWO MATTERS CII1.-The Colotwiq Matters occurrhg ill cccrioiis Bj-itish Plctnts. Part I. By ARTHUR GEORGE PERKIX and JOHN JAMES HUMMEL. SIWE the introduction of coal-tar colours, comparatively little atten- tion has been paid to the colouring matters of plants, especially of British plants ; it is well known, however, that, in the past, many of these have been employed in dyeing, and that this is the case even at the present time in remote districts, notably in the Highlands of Scotland, some few native plants being used for this purpose. By means of an extended series of dyeing experiments,* it has been ascertained by one of us that many British plants appear to be sufficiently rich in colouring matter (chiefly Yellow) to make them worthy of chemical examination.Jn many cases this will probably be a matter of some difficulty, partly because it is not always easy to obtain the requisite quantity of raw material, and partly because the amount of colouring matter present, even in the best circumstances, will be only very limited. The study of the various natural yellow colouring matters is particularly interesting, however, at the present time, because their chemical constitution, of which chemists have long been ignorant, is now being gradually made known, and it may be that Eome of those occuri*ing in British plants will fill up gaps in the comparatively limited series with which ve are at present acquainted. Even in the event of many proving to be identical with those already known, the investigation sliould still have an interest as showing the wide distribution of certain colourirlg matters hitherto only known to exist in a few plants.The Colowing Matters contaitied iir the Yellow IVaZZ$ou~er (Cheirantlins ckeiri). A preliminary dyeing experiment with the purplish-brown petals of the common garden wallflower showed them to be comparati~elg rich in colouring matter, but since the colour with alumina \xis not * The results of these dyeing experiments will be communicated ekewhcrc at a later date.OCCURRING IN VARIOUS BRITISH PLANTS. 1567 pure, being greenish-olive yellow, a similar experiment was made with the bright yellow Aowers of the variety known as " Cloth of Gold." As expected, these yielded a bright yellow with alumina mordant, and, indeed, their general dyeing properties were very similar to those of such well-known dye-stuffs as quercitron bark, &c, For t-he purpose of chemical examination, a pound of the flowers was extracted with boiling water, and after allowing the decoction to cool, and filtering off deposited flocculent matter, the filtrate was acidified with sulphuric acid, and boiled.On cooling, a moderate quantity of an olive-yellow precipitate separated ; this was collected, washed, dried, and examined as follows. The semi-crystalline product was digested with boiling alcohol, when the colouring matter passed into solution and a nearly colour- less, crystalline residue of calcium sulphate was left. On evapo- ration, the alcoholic extract deposited crystals, but these were intermingled with a wax-like substance, which could not be readily removed by recrystallisation ; the concentrated solution was, therefore, poured into a large volume of ether, the mixture washed several limes with water, and then extracted with dilute alkali, which removed the colouring matter, leaving the wax in solution in the ether. The alkaline liquid was neutralised, the precipitated colouring matter again dissolved in ether, and the ethereal solution evaporated to dryness.On examination, the bright yellow product was found to consist of two substances, for, when suspended in boil- ing acetic acid, and treated with hjdrobromic acid, an orange- coloured, crystalline hydrobromide was produced, but intermingled with particles of a yellow substance, which refused to react with the Iialoi'd acid in this way.Experiment, moreover, showed that these two Substances were readily distinguished from one another by t h e difference in their solubilities in alcohol ; this was sufficiently marked to render their separation comparatively easy. As the more soluble colouring matter was present in by far the greater proportion, this was first examined. It was best purified by crystallisation from alcohol and water, and was thus obtained in the form of glistening, yellow needles. 0.1362 gave 0.2549 CO, and 0.0325 H,O. CI5Hl007 reqnires C = 59.60; H = 3-31 per cent. Dilute alkalis dissolved it with a yellow coloration ; with lead acetate in alcoholic solution, an orange-red precipitate was formed, whilst alcoholic ferric chloride gave a dark green coloration.Treated with mineral acids in the presence of acetic acid, orange to orange-red crystalline compounds were produced, SO that it is evident that not this but the mwe insoluble colouring matter was uureactive with C = 59.82; H = 3.10.1568 PEREIN AND ETUMMITL : TIIE COLOURIX'GI MATTERS the haloid acids. Digested with acetic anhydride and sodinnl acetate in the usual way, an acetyl compound was obtained, crjstal- lising from alcohol in colourless needles melting a t 189--19lo. 0 1271 gave 0.2730 CO, and 0.0477 H,O. C = .W58 ; H = 4.16. C,,H5Oi(C2H,O), requires C = 58.59 ; H = 3-90 per cent. The colourhg matter was digested with fused alkali a t 180-200° for half an hour, the melt dissolved in water, neutralised with acid, and the products of the action extracted from the solution with ether.The small quantity of crystalline matter thus obtained was found to be a mixture of two substances which could be readily seprrrated, in that, in aqueous solution, one only gave a precipitate with lead acetate; on decomposing this, it yielded a substance crjstallising from water in colourless needles melting a t 195O, and identical with protocntechuic acid. The filtrate from the lead precipitate gave the yhloroglucinol reac- tion. There coiild be no doubt, therefore, that tjhe more soluble colonring matter, C15H1007, is puercetin, a fact which was further corroborated by its dyeing properties being identical wit'h those of quercetin pre- Fared from quercitron bark. Spaiingly Soluble Colouring Matfey.--This was purified by several crjstallisations from alcohol, and was thus obtained in the form of minute, yellow needles.0.1141 gave 0.2533 C 0 2 and 0.0420 H,O. C,,H,,O, requires C = 60.75 ; H = 3.79 per cent. Although considerably less soluble in alcohol and acetic acid than quercetin, yet, in its principal reactions, it closely resembled it, for it dissolved in dilute alkaline solutions with a yellow colour ; with lead acetate, it gare an orange-red precipitate ; and with alcoholic ferric chloride a dark green coloration. As before stated, when treated with halo'id acids in the presence of boiling acetic acid, it did not yield a compound with the acid, although, with sulphuric acid in a similar manner, an orange-rcd, crystalline substance was produced. Its behaviour in this respect corresponded with that of the known methyl ethers of quercetin, rhnmnetin (quercetin mononiethyl ether), rhamnazin (quercetin dimetl yl etl.er), a a d quercetin tetramethyl ether, which have been previously studied by one of us and L.Pate ('rrans., 1895, 650 ; 1F96, 1443), and it was, therefore, suspected that this colouring matter also contained a methoxg-group. An experi- ment by Zeisel's method gare the following result: C = 60.54; H = 4.09. 0.1437 gave 0.1040 AgI. CH, = 4.62. C15H,0,*OCH, requires CH, = 4.68 per cent.OCCURRING IN VARIOUS BRITISH PLINTS. 1569 It, therefore, contained one methoxy-grodp. To the hydriodic acid residue, after dilution with water, sodium hydrogen sulphite solution was added, and the yellow, floxulent product collected arid crysta!- lised from dilute alcohol ; it was thus obtained as a glistening mass of yellow needles, and appeared to be pwsrcstin. This wag coqfirmed by converting it into an acetyl corupound; the latter crystallised from alcohol in colourless needles melting a t 189-191', and was found to be ideiiticrtl with acetylquercelin.Tho colouring matter, C16H1?07, is, therefore, a quercetin monomethyl ether. The only known monomethyl ether of quercetin is rhamnetin, present in Pers:an berries i n the form of a glucoside, xanthorham- nin. As, in appearance and ganeral properties, the colouring matter, C16H,20,, was very similar to rhamnetin, it seemed possible fhat the two were identical ; to determine this point, the small quantity of the substance, ClsH1207, that remained was converted iuto an acetjl compound, and this crystallised in colourless needles melting at 195-196'.It, therefore, appeared that this siibstance could not be rhamnetin, for the melting point of its acetyl compound is given by Liebermann and Hormnnn ( B e y . , 11, 1618) as 181--18;3O, and by Herzig (Monatsh., lW3, 9, 548) as 183-185O. Since the publica- tion of these papers, however, it has been shown by one of us and J. Geldard (Trans., 1895, 67, 496), that Persian berries contain, not only rhamnctin and querceth, but a third substance, rhamnaziri, and it was thus possible that the melting point of acetylrhamnetin might be higher than that given above. Experiments, however, with rhnmxietin, which had been submitted to puriticstion in various ways, failed to support this supposition, the acetyl compound in each case melting at 185-186'.Moreover, when the acetyl compound cf rhamnetin and that of the substance Cl6H;,O, were crystallised from alcohol side by side, and under similar circumstances, they could be readily clistinguiBhrd from one another; for, whereas the latter always separated as a semi-solid, spongy mass of hair-like needles, the crystals of the former, which were considerably larger in size, readily sattled down in the mother liquor on agitation. There could be no doubt, therefore, that the substance, C16H1207, is a new quercetin monomethyl ether, and for it we propose the name Isorhamnetin. As it is not possible to obtain a further supply of the flowers Lill next summer, some time must elapse before attempting to decide the position of the methoxy-group in this substance. Eren f,hen the small amount of this product which is present in the plant, must recder this a work of considerable difficulty, and may delay the results shill fprther.The t o t d quantify of isorhamnetin obfained from tho flowers being not mom than 0.4 gram, sufficient mas not available f o r any thorough1570 PERKIN AND HUMMEL: THE COLOURXNO MATTERS dyeing experiments. A single trial, using the ordinary striped mop- danted calico, indicated that its properties, i n this respect, were, also, closely similar to those of both quercetin and rhamnetin-these two colouring matters themselves yielding in this way almost identical shades. Experiments in this direction will b3 carried out in detail when more of the colouring matter is to hand.The Colouring Matter in White Hawthom Blossom (Cratagus Oxyacantha) . Examination having showed that white hawthorn flowers contain it yellow colouring matter, and, the present season being particularly favourable, about 20 lbs. of the flowers were collected for examination. These were treated in the manner above described in connection with the examination of wall-flowers. In this case the precipitate obtained was of a rich chocolate-brown, and, although produced in moderate quantity (as will be seen below) it yielded, ultimately, a very small quantity of pure colouring matter. The isolation of the pure colouring matter from this product, by t.he methods usually found serriceable for such a purpose, gave exceedingly unsatisfactory results, as, in each instance, it was so contaminated with resinous matter, that its purification could only be accomplished with con- siderable loss.Eventually a method, similar to that previously employed for the isolation of the colouring matter of Quebracho coloyado (Trans., 1896, 69, 1303), was found to be the most service- able. For this purpofie, the crude product was dissolved in alcohol, poured into a large quantity of cold water, excess of sulphnric acid added, and the mixture heated to the boiling point. As the tempera- ture rose, the suspended, brown, flocculent precipitate gradually aggregated, forming a black, tarry mass, and the digestion was con- tinued until the supernatant liquor, at first somewhat milky, became clear; this, after decantation, mas extracted with ether, and the extract evaporated, a light brown, sticky product being thus obtained, from which crystals of the colouring matter separated after long standing.Digestion with boiling chloroform remored from this some of the impurity, these extracts being placed aside for examin% fion (A). The residue was now further purified by. crystallisation from dilute alcohol, but still contained a brown matter which could not be removed by similar treatment ; i t was, therefore, converted into an acetyl derivative. This, which crystallised from alcohol in colour- less needles, was decomposed in the usual way, and the regenerated colouring mattel* crystallised from dilute alcohol. By this means only 0.5 gram of the purified product was obtained, but i t is most probable that a portion was retained by the tarry matter mentionedOCCURRING IN VARIOUS BRITISH PLANTS.1571 above. It was subsequently found that, by treating an aqueous decoction of the flowers with lead acetate solution, decomposing the precipitated lead compound with sulphuric acid, and extracting the acid solution with ether, the colouring matter could be obtained in a condition which lent itself more readily to purification. At this time, however, no more raw material was available, though, fortu- natcly, the quantity of substance obtained by the former method was found to be sufficient for the identification of this colouring matter. C = 59.40 ; H = 3.61. 0.1100 gave 0.2396 CO, and 0.0358 H,O. C1,H,oO, requires C = 59 60; H = 3.31 per cent.It formed a glistening mass of yellow needles, readily soluble in alcohol, mid soluble in alkalis with a yellow coloration. In alcohoIic solution, lead acetate yielded an orange-red precipitate and ferric chloride a dark green colorcdion. With mineral acids, it yieIded crjs- talline compounds. AcetyZ Derivutiz;e.--By crystallisation from alcohol this mas obtained 8 6 colonrless needles melting at 189-191'. 0.1195 gave 0.2556 CO, and 0.0437 H20. C = 58-33; H = 4.06. Action of Fused AEkaZi.-For this purpose, but 0-1 gram WBS arail- able. The products of the action were readily separated by means af lead acetate in aqueous solution, in that ouly one of them yielded a, precipitate with this reagent. By decomposition, i n the usual way, the lead compound yielded a trace of a crystalline substance, a solu- tion of which gave with ferric chloride a green coloration, from whicli it appeared to be protocatechuic acid.The filtrate from the lead pre- cipitate gave the phloroglwcinol reaction. As was to be expected from the above results, a dyeing trial corroborated the fact that the colouring matter of hawthorn blossom i s quercetin. On nllo.cviiig the chloroform extract (A), obtained during the puri- fication of the colouring matter, to evaporate spontaneously, it deposited a very small quantity of crystalline substance intermingled with a brown sticky product. B y recrystallisation, first from benzene and then from water, it was obtained in colourless needles melting at 177-17&', and subliming unchanged, soluble in dilute alkalis, but yielding no coloration with ferric chloride in aqueous solution. The quantity available was far too small for analysis, and its examina- tion must, thereEore, await a further supply of raw material, Its general properties, however, suggesteii that it might be veratric (dimethylprotocatechuic) acid. It will be of interest also, if possible, to isolate and study the sub- stance which yields the brown precipitate when the extract is digested C15H507(CZH30)5 requires C = 58.59 ; H = 3.90 per cent.1572 CEATTAWAY: THE CONSTITUTION OF THE with boiling dilute acids. This reaction snggests that it is possibly's catechin-like compound, the brown prodact, i n its nature, resembling t h a t formed when either catechin, or cyanomaclurin is similarly treated. That the above colouring matters exist in these flowers in the form of glucosides there c m be little doubt, and at a convenient opportunity they will be subjected to examination. For the present, however, it appears to us that more interest is attaf;hed to the examination of the colouring matters themselves than to their glucosides, it being possible that in some of these plants missing members of the qnercetin or xanthone series may exist. Clothworkers' Research Laboratory, Dyeing Department, T'orkshire Col Eege.

ISSN:0368-1645    

DOI:10.1039/CT8966901566

出版商:RSC    

年代:1896

数据来源: RSC